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History of Technology

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Heroes and Villains - A little light reading

Here you will find a brief history of technology. Initially inspired by the development of batteries, it covers technology in general and includes some interesting little known, or long forgotten, facts as well as a few myths about the development of technology, the science behind it, the context in which it occurred and the deeds of the many personalities, eccentrics and charlatans involved.

"Either you do the work or you get the credit" Yakov Zel'dovich - Russian Astrophysicist

Fortunately it is not always true.

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You may find the Search Engine, the Technology Timeline or the Hall of Fame quicker if you are looking for something or somebody in particular.

See also the timelines of the Discovery of the Elements and Particle Physics and Quantum Theory.

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The Content - It's not just about batteries. Scroll down and see what treasures you can discover.


We think of a battery today as a source of portable power, but it is no exaggeration to say that the battery is one of the most important inventions in the history of mankind. Volta's pile was at first a technical curiosity but this new electrochemical phenomenon very quickly opened the door to new branches of both physics and chemistry and a myriad of discoveries, inventions and applications. The electronics, computers and communications industries, power engineering and much of the chemical industry of today were founded on discoveries made possible by the battery.


It is often overlooked that throughout the nineteenth century, most of the electrical experimenters, inventors and engineers who made these advances possible had to make their own batteries before they could start their investigations. They did not have the benefit of cheap, off the shelf, mass produced batteries. For many years the telegraph, and later the telephone, industries were the only consumers of batteries in modest volumes and it wasn't until the twentieth century that new applications created the demand that made the battery a commodity item.

In recent years batteries have changed out of all recognition. No longer are they simple electrochemical cells. Today the cells are components in battery systems, incorporating electronics and software, power management and control systems, monitoring and protection circuits, communications interfaces and thermal management.

History of Technology from the Bronze Age to the Present Day

Circa 3000 B.C. At the end of the fourth millennium B.C. the World was starting to emerge from the Stone Age.

Around 2900 B.C., Mesopotamians (from modern day Iraq), who had already been active for hundreds of years in primitive metallurgy extracting metals such as copper from their ores, led the way into the Bronze Age when artisans in the cities of Ur and Babylon discovered the properties of bronze and began to use it in place of copper in the production of tools, weapons and armour. Bronze is a relatively hard alloy of copper and tin, better suited for the purpose than the much softer copper enabling improved durability of the weapons and the ability to hold a cutting edge. The use of bronze for tools and weapons gradually spread to the rest of the World until it was eventually superceded by the much harder iron.

Mesopotamia, incorporating Sumer, Babylonia and Assyria, known in the West as the Cradle of Civilisation was located between the Tigris and Euphrates rivers (The name means "land between the rivers") in the so called Fertile Crescent stretching from the current Gulf of Iran up to modern day Turkey. The ancient city of Babylon which served for nearly two millennia as a center of Mesopotamian civilization is located about 60 miles (100 kilometers) south of Baghdad in modern-day Iraq. (See Map of Mesopotamia).

Unfortunately this accolade ignores the contributions of the Chinese people and the Harappans of the Indus Valley, (Modern day Pakistan) who were equally "civilised" during this period practicing metallurgy (copper, bronze, lead, and tin) and urban planning, with civic buildings, baked brick houses, and water supply and drainage systems.

From around 3500 B.C. the Sumerians of ancient Mesopotamia developed the World's first written language. Called Cuneiform Writing from the Latin "cuneus", meaning "wedge", it was developed as a vehicle for commercial accounting transactions and record keeping. The writing was in the form of a series of wedge-shaped signs pressed into soft clay by means of a reed stylus to create simple pictures, or pictograms, each representing an object. The clay subsequently hardened in the Sun or was baked to form permanent tablets. By 2800 B.C. the script progressively evolved to encompass more abstract concepts as well as phonetic functions (representing sounds, just like the modern Western alphabet) enabling the recording of messages and ideas. For the first time news and ideas could be carried to distant places without having to rely on a messenger's memory and integrity.

Hieroglyphic script evolved slightly later in Egypt. Though the script appeared on vases and stone carvings, many important Egyptian historical scripts and records were written in ink, made from carbon black (soot) or red ochre mixed with gelatin and gum, applied with a reed pen onto papyrus. Produced from the freshwater papyrus reed, the papyrus scrolls were fragile and susceptible to decay from both moisture and excessive dryness and many of them have thus been lost, whereas the older, more durable clay cuneiform tablets from Mesopotamia have survived.

Historians seem to agree that the wheel and axle were invented around 3500 B.C. in Mesopotamia. Pictograms on a tablet dating from about 3200 B.C. found in a temple at Erech in Mesopotamia show a chariot with solid wooden wheels. Evidence from Ur indicates that the simpler potter's wheel probably predates the use of the axled wheel for transport because of the difficulty in designing a reliable mechanism for mounting the rotating wheel on a fixed hub or a rotating axle on the fixed load carrying platform.

Sumerian mathematics and science used a base 60 sexagesimal numeral system. 60 is divisible by 1,2,3,4,5,6,10,12,15,20,30 and 60 making it more convenient than using a base 10 decimal system when working with fractions. The Mesopotamians thus introduced the 60-minute hour, the 60-second minute and the 360-degree circle with each angular degree consisting of 60 seconds. The calendar adopted by the Sumerians, Babylonians and Assyrians was based 12 lunar months and seven-day weeks with 24-hour days. Since the average lunar month is 29.5 days, over 12 months this would produce a total of only 354 days as against a solar year of 365.25 days. To keep the calendar aligned to the seasons they added seven extra months in each period of 19 years, equivalent to the way we add an extra day in leap years. Despite decimalisation, we still use these sexagesimal measures today.

The Mesopotamians discovered glass, probably from glass beads in the slag resulting from experiments with refining metallic ores. They were also active in the development of many other technologies such as textile weaving, locks and canals, flood control, water storage and irrigation.

There are also claims that the Archimedes' Screw may have been invented in Mesopotamia and used for the water systems at the Hanging Gardens of Babylon.

2500 B.C. Sometimes known as the "Second oldest profession", soldering has been known since the Bronze Age (Circa 3000 to 1100 B.C.). A form of soldering to join sheets of gold was known to be used by the Mesopotamians in Ur. Fine metal working techniques were also developed in Egypt where filigree jewellery and cloisonné work found in Tutankhamun's tomb dating from 1327 B.C. was made from delicate wires which had been drawn through dies and then soldered in place.

Egypt was also home to Imhotep the first man of science in recorded history. He was the world's first named architect and administrator who around 2725 B.C. built the first pyramid ever constructed, the Stepped Pyramid of Saqqara. Papyri were unearthed in the nineteenth century dating from around 1600 B.C. and 1534 B.C. both of which refer to earlier works attributed to Imhotep. The first outlines surgical treatments for various wounds and diseases and the second contains 877 prescriptions and recipes for treating a variety of medical conditions making Imhotep the world's first recorded physician. Other contemporary papyri described Egyptian mathematics. Egyptian teachings provided the foundation of Greek science and although Imhotep's teachings were known to the Greeks, 2200 years after his death, they assigned the honour of Father of Medicine to Hippocrates.

2300 B.C. The earliest evidence of the art of stencilling used by the Egyptians. Designs were cut into a sheet of papyrus and pigments were applied through the apertures with a brush. The technique was reputed to have been in use in China around the same time but no artifacts remain.

2100-1600 B.C. The Xia dynasty in China perfected the casting of bronze for the production of weapons and ritual wine and food vessels, reaching new heights during the Shang dynasty (1600-1050 B.C.).

Circa 2000 B.C. The process for making wrought iron was discovered by the Hittites, in Northern Mesopotamia and Southern Anatolia (now part of Eastern Turkey), who heated iron ore in a charcoal fire and hammered the results into wrought (worked) iron. See more about wrought iron

1300 B.C. Fine wire also made by the Egyptians by beating gold sheet and cutting it into strips. Recorded in the Bible, Book of Exodus, Chapter 39, Verse 3, - "And they did beat the gold into thin plates, and cut it into wires, to work it. in the fine linen, with cunning work."

The Egyptians also made coarse glass fibres as early as 1600 B.C. and fibers survive as decorations on Egyptian pottery dating back to 1375 B.C.

1280 B.C. Around this date, after his escape from Egypt, Moses ordered the construction of the Ark of the Covenant to house the tablets of stone on which were written the original "Ten Commandments". Its construction is described in great detail in the book of Exodus and according to the Bible and Jewish legend it was endowed with miraculous powers including emitting sparks and fire and striking dead Aaron's sons and others who touched it. It was basically a wooden box of acacia wood lined with gold and also overlaid on the outside with gold. The lid was decorated with two "cherubim" with outstretched wings. In 1915 Nikola Tesla, in an essay entitled "The Fairy Tale of Electricity" promoting the appreciation of electrical developments, proposed what seemed a plausible explanation for some of the magical powers of the Ark. He claimed that the gold sheaths separated by the dry acacia wood effectively formed a large capacitor on which a static electrical charge could be built up by friction from the curtains around the Ark and this accounted for the sparks and the electrocution of Aaron's sons.

Recent calculations have shown however that the capacitance of the box would be in the order of 200 pico farads and such a capacitor would need to be charged to 100,000 volts to store even 1 joule of electrical energy, not nearly enough to cause electrocution. It seems Tesla's explanation was appropriately named.

800 B.C. The magnetic properties of the naturally occurring lodestone were first mentioned in Greek texts. Also called magnetite, lodestone is a magnetic oxide of iron (Fe3O4) which was mined in the province of Magnesia in Thessaly from where the magnet gets its name. Lodestone was also known in China at that time where it was known as "love stone" and is in fact quite common throughout the world.

Surprisingly although they were aware of its magnetic properties, neither the Greeks nor the Romans seem to have discovered its directive property.

Eight hundred years later in 77 A.D., the somewhat unscientific Roman chronicler of science Pliny the Elder, completed his celebrated series of books entitled "Natural History". In it, he attributed the name "magnet" to the supposed discoverer of lodestone, the shepherd Magnes, "the nails of whose shoes and the tip of whose staff stuck fast in a magnetic field while he pastured his flocks". Thus another myth was born. Pliny was killed during the volcanic eruption of Mount Vesuvius near Pompeii in A.D. 79 but his "Natural History" lived on as an authority on scientific matters up to the Middle Ages.

600 B.C. The Greek philosopher and scientist, Thales of Miletus (624-546 B.C.) - one of the Seven Wise Men of Greece (Miletus is now in Turkey) - was the first thinker to attempt to explain natural phenomena by means of some underlying scientific principle rather than by attributing them to the whim of the Gods - a major departure from previous wisdom and the foundation of scientific method, frowned upon by Aristotle but rediscovered during the Renaissance and the Scientific Revolution.

He travelled to Egypt and the city state of Babylon in Mesopotamia (now modern day Iraq) and is said to have brought Babylonian mathematics back to Greece. The following rules are attributed to him:

  • Any angle inscribed in a semicircle is a right angle. Known as the Theorem of Thales it was however known to the Babylonians 1000 years earlier.
  • A circle is bisected by any diameter.
  • The base angles of an isosceles triangle are equal.
  • The opposite angles formed by two intersecting lines are equal.
  • Two triangles are congruent (equal shape and size) if two angles and a side are equal.
  • The sides of similar triangles are proportional

Using the concept of similar triangles he was able to calculate the height of pyramids by comparing the size of their shadows with smaller, similar triangles of known dimensions. Similarly he calculated the distance to ships at sea by noting the azimuth angle of the ship from a baseline of two widely spaced observation points a known distance apart on the shore and scaling up the distance to the ship from the dimensions of a smaller similar triangle. In this way he was able to calculate the distance to far off objects without measuring the distance directly, the basis of modern surveying.

Thales also demonstrated the effect of static electricity by picking up small items with an amber rod made of fossilised resin which had been rubbed with a cloth. He also noted that iron was attracted to lodestone.

Thales left no writings and knowledge of him is derived from an account in Aristotle's Metaphysics written nearly 300 years later and itself subject to numerous subsequent copies and translations.

530 B.C. Pythagoras of Samos (580-500 B.C.) an Ionian Greek, is considered by many to be the Father of Mathematics. Like Thales, he had travelled to Egypt and Babylon where he studied astronomy and geometry. His theorem. "In a right-angled triangle the square on the hypotenuse is equal to the sum of the squares on the other two sides" is well known to every schoolchild.

Around 530 BC, he moved to Croton, in Magna Graecia, where he set up a religious sect. His cult-like followers, were enthralled by numbers such as prime numbers and irrational numbers and considered their work to be secret and mystical. Prior to Pythagoras, mathematicians had dealt only in whole numbers and fractions or ratios but Pythagoras brought them into contact with √2 and other square roots which were not rational numbers.

Pythagoreans also discovered the Divine Proportion, also called the Golden Mean or Golden Ratio, an irrational number Φ (Phi) = (√5+1)/2 ≈ 1.618 which has fascinated both scientists and artists ever since.

(See examples of The Divine Proportion).

None of Pythagoras writings have survived and knowledge of his life and works is based on tradition rather than verified facts.

Circa 500 B.C. Cast iron was produced for the first time by the Chinese during the Zhou dynasty (1046-256 B.C.). Prior to that, it had not been possible to raise the temperature of the ore sufficiently to melt the iron and the only available iron was wrought iron created by heating iron ore in a furnace with carbon as the reducing agent and hammering the resulting spongy iron output. Furnaces of the day could reach temperatures of about 1300°C which was enough to melt copper whose melting point is 1083°C but not enough to melt iron whose melting point is 1528°C. By a combination of the addition of phosphorus to the ore which reduced its melting point, the use of a bellows to pump air through the ore to aid the exothermic reduction process and the use of improved high temperature refractory bricks forming the walls of the furnace to withstand the heat, the Chinese were able to melt the iron and cast it into functional shapes ranging from tools and pots and pans to heavy load bearing constructional members as well as fine ornamental pieces.

Cast iron was not produced in Europe till around 1400 A.D.. Gun-barrels and bullets were the first cast iron products to be manufactured but it was not until 1709 when Abraham Darby introduced new production methods that low cost, volume production was achieved.

See more about Chinese Inventions.

460 B.C. Another Greek philosopher Democritus of Abdera developed the idea that matter could be broken down into very small indivisible particles which he called atoms. Subsequently Aristotle dismissed Democritus' atomic theory as worthless and Aristotle's views tended to prevail. It was not until 1803 that Democritus' theory was resurrected by John Dalton.

380 B.C. Greek philosopher Plato (Circa 428-347) composed the Allegory of the Cave as part of his major work, the Republic.

He believed that there were patterns or mathematical relationships, we now would call "science", behind natural phenomena which were often hidden from the observer and difficult to observe directly.

In his allegory he described a community of prisoners permanently chained from birth to the floor of a cave facing a blank wall with no possibility to look elsewhere. See diagram of Plato's Cave. Behind the prisoners was a low wall concealing from them an elevated walkway or stage. People could walk around this stage, out of sight of the prisoners, carrying 3D objects or puppets above their heads. A fire behind the stage next to the back wall of the cave illuminated these moving objects which cast shadows on the blank wall in front of the prisoners. Any sounds of the people talking, or other movements, echoed off the walls so that the prisoners believed these sounds came from the shadows.

For the prisoners, these shadows were the reality. This was their World. They had no way of knowing that a different true reality existed. If the reality were explained to them they would probably not believe it.

The cave allegory illustrated fundamental issues in science such as:

  • The observer's perception of reality suffers from incomplete information and the difficulty of interpreting the information which is avavailable.
  • It is dangerous to infer anything about reality based on our experiences.

Plato's observations still hold good today, 2400 years later, particularly with particle physics where all is not what it seems.

350 B.C. The Greek philosopher and scientist Aristotle (384-322 B.C.), student of Plato, provided "scientific" theories based on pure "reason" for everything from the geocentric structure of the cosmos down to the four fundamental elements earth, fire, air and water.

Aristotle believed that knowledge should be gained by pure rational thought and had no time for mathematics which he regarded only as a calculating device. Neither did he support the experimental method of scientific discovery, espoused by Thales, which he considered inferior. In his support it should be mentioned that the range of experiments he could possibly undertake was limited by the lack of suitable accurate measuring instruments in his time and it was only in the seventeenth century during the Scientific Revolution that such instruments started to become available.

Unfortunately Aristotle's "rational" explanations were subsequently taken up by St Thomas Aquinas (1225-1274) and espoused by the church which for many years made it difficult, if not dangerous, to propose alternative theories. Aristotle's theories of the cosmos and chemistry thus held sway for 2000 years hampering scientific progress until they were finally debunked by Galileo, Newton and Lavoisier who showed that natural phenomena could be described by mathematical laws.

See also Gilbert (1600), Mersenne (1636), Descartes (1644) and Von Guericke (1663) and the Scientific Revolution.

Aristotle was also a tutor to the young Alexander the Great.

Like many sources from antiquity, Aristotle's original manuscripts have been destroyed or lost and we only know of Aristotle's works via series of copies and translations from the Greek into Arabic, then from Arabic into Latin and finally from Latin into English and other modern languages. There's much that could have been lost, changed or even added in the translations.

332 B.C. Alexander the Great conquered Egypt and ordered the building of a new city on the Egyptian, Nile delta named after himself - Alexandria. When he died in 323 BC his kingdom was divided between three of his generals, with Egypt going to Ptolemy (367–283 B.C.) who later declared himself King Ptolemy I Soter (not to be confused with Claudius Ptolemy (90-168 A.D.)) and founded a new dynasty, replacing the Pharaohs, which lasted until the Roman conquest of 30 B.C.

Ptolemy Soter's grandest building project in the new capital was the Musaeum or "Temple of the Muses" (from which we get the modern word "museum") which he founded around 306 B.C. A most important part of the Musaeum was the famous Library of Alexandria, which he conceived, and which was carried through by his son Ptolemy II Philadelphus, with the object of collecting all the world's knowledge. Most of the staff were occupied with the task of translating works onto papyrus and it is estimated (probably over-estimated) that as many as 700,000 scrolls, the equivalent of more than 100,000 modern printed books, filled the library shelves.

Great thinkers were invited to Alexandria to establish an academy at the library turning it into a major centre of scholarship and research. Euclid was one of the first to teach there. Ultimately the library overshadowed the Musaeum in importance and interest becoming perhaps the oldest university in the world.

It was at the library that:

  • Euclid developed the rules of geometry based on rigorous proofs. His mathematical text was still in use after 2000 years.
  • Archimedes invented the a water pump based on a helical screw, versions of which are still in use today. (The actual date of this invention is however disputed).
  • Eratosthenes measured the diameter of the Earth.
  • Hero invented the aeolipile, the first reaction turbine.
  • Claudius Ptolemy wrote the Almagest, the most influential scientific book about the nature of the Universe for 1,400 years.
  • Hypatia, the first woman scientist and mathematician invented the hydrometer, before she met her untimely end during Christian riots.

Alas the ancient library is no more. Four times it was devastated by fire, accidental or deliberate, during wars and riots and historians disagree about who were the major culprits, their motives and the extent of the damage in each case.

  • 48 B.C. Damage caused during the Roman conquest of Egypt by Julius Caesar
  • 272 A.D. An attack on Queen Zenobia of Palmyra by Roman Emperor Aurelian
  • 391 A.D. An edict of the Emperor Theodosius I made paganism illegal and Patriarch Theophilus of Alexandria ordered demolition of heathen temples. This was followed by Christian riots the same year and 415 A.D..
  • 639 A.D. The Muslim conquest of Alexandria by General Amr ibn al 'Aas leading the army of Caliph Omar of Baghdad.

But even without the wars, the delicate papyrus scrolls were apt to disintegrate with age and what was left of the library eventually succumbed to the ravages of major earthquakes in Crete in A.D. 365 and 1303 A.D. which caused tsunamis which in turn devastated Alexandria.

300 B.C. Fl Greek mathematician Euclid of Alexandria (Circa 325-265 B.C.) a great organiser and logician, taught at the great Library of Alexandria and took the current mathematical knowledge of his day and organised it into a manuscript consisting of thirteen books now known as Euclid's Elements. Considered by many to be the greatest mathematics text book ever written it has been used for over 2000 years. Nine of these books deal with plane and solid geometry, three cover number theory, one (book 10) concerns incommeasurable lengths which we would now call irrational numbers.

Proof, Logic and Deductive Reasoning

The "Elements" were not just about geometry, Euclid's theorems and conclusions were backed up by rigorous proofs based on logic and deductive reasoning and he was one of the first to require that mathematical theories should be justified by such proofs.

An example of the type of deductive reasoning applied by Euclid is the logical step based on the logical principle that if premise A implies B, and A is true, then B is also true, a principle that mediaeval logicians called modus ponens (the way that affirms by affirming). A classical example of this is the conclusion drawn from the following two premises: A: "All men are mortal" and B: "Socrates is a man" then the conclusion C: "Socrates is mortal" is also true.

In this manner Euclid started with a small set of self evident axioms and postulates and used them to produce deductive proofs of many other new propositions and geometric theorems. He wrote about plane, solid and spherical geometry, perspective, conic sections, and number theory applying rigorous formal proofs and showed how these propositions fitted into a logical system. His axioms and proofs have been a useful set of tools for many subsequent generations of mathematicians, demonstrating how powerful and beneficial deductive reasoning can be.

An example of Euclid's logical deduction is the method of exhaustion which was used as a method of finding the area of an irregular shape by inscribing inside it a sequence of n regular polygons of known area whose total area converges to the area of the given containing shape. As n becomes very large, the difference in area between the given shape and the n polygons it contains will become very small. As this difference becomes ever smaller, the possible values for the area of the shape are systematically "exhausted" as the shape and the corresponding area of the series of polygons approaches the given shape. This sets a lower limit to the possible area of the shape.

The method of exhaustion used to find the area of the shape above is a special case of of proof by contradiction, known as reductio ad absurdum which seeks to demonstrate that a statement is true by showing that a false, untenable, or absurd result follows from its denial, or in turn to demonstrate that a statement is false by showing that a false, untenable, or absurd result follows from its acceptance.

In the case above this means finding the area of the shape by first comparing it to the area of a second region inside the shape (which can be "exhausted" so that its area becomes arbitrarily close to the true area). The proof involves assuming that the true area is less than the second area, and then proving that assertion false. This gives a lower limit for the area of the shape under consideration.

Then comparing the shape to the area of a third region outside of the shape and assuming that the true area is more than the third area, and proving that assertion is also false. This gives an upper limit for the area of the shape.

No original records of Euclid's work survive and the oldest surviving version of "The Elements" is a Byzantine manuscript written in A.D. 888. Little is known of his life and the few historical references to Euclid which exist were written centuries after his death, by Greek mathematician Pappus of Alexandria around 320 A.D. and philosopher and historian Proclus around 450 A.D.

According to Proclus, when the ruler Ptolemy I Soter asked Euclid if there was a shorter road to learning geometry than through the Elements, Euclid responded "There is no royal road to geometry".

269 B.C. The greatest mathematician and engineer in antiquity, the Greek Archimedes of Syracuse (287-212 B.C.) began his formal studies at the age of eighteen when he was sent by his father, Phidias, a wealthy astronomer and kinsman of King Hieron II of Syracuse, to Egypt to study at the school founded by Euclid in the great Library of Alexandria. It kept him out of harm's way in the period leading up to the first Punic war (264-241 B.C.) between Carthage and Rome when Sicily was still a colony of Magna Graecia, vulnerably situated in strategic territory between the two adversaries. Syracuse initially supported Carthage, but early in the war Rome forced a treaty of alliance from king Hieron that called for Syracuse to pay tribute to the Romans. Returning to Syracuse in 263 B.C. Archimedes became a tutor to Gelon, the son of King Hieron.

Archimedes' Inventions

Archimedes was known as an inventor, but unlike the empirical designs of his predecessors, his inventions were the first to be based on sound engineering principles.

He was the world's first engineer, the first to be able to design levers, pulleys and gears with a given mechanical advantage thus founding the study of mechanics and the theory of machines.

Archimedes also founded the studies of statics and hydrostatics and was the first to elucidate the principle of buoyancy and to use it in practical applications.

  • Though he did not invent the lever, he explained its mechanical advantage, or leverage, in his work "On the Equilibrium of Planes" and is noted for his claim "Give me a place to stand and a long enough lever and I can move the Earth".
  • Archimedes' explanation of the theory of the lever is based on the principle of balancing the input and output torques about the fulcrum of the device so that, the input force multiplied by its distance from the fulcrum, is equal to the weight (or downward force) of the load multiplied by its distance from the fulcrum. In this arrangement, the distance moved by each force is proportional to its distance from the fulcrum. Thus a small force moving a long distance can lift a heavy load over a small distance and the mechanical advantage is equal to the ratio of the distances from the fulcrum of the points of application the input force and the output force. He applied similar reasoning to explain the operation of compound pulleys and gear trains, in the latter case using angular displacement in place of linear displacement.

    We would now relate this theory to the concepts of work done, potential energy and the conservation of energy. See also hydraulic, mechanical advantage described by Pascal.

  • He is credited by the Greek historian Plutarch (46-120 A.D.), with inventing the block and tackle / compound pulley to move ships and other heavy loads. The use of a simple, single-sheaved pulley to change the direction of the pull, for drawing water and lifting loads had been known for many years. This device did not provide any mechanical advantage, but Archimedes showed that a multi-sheaved, compound pulley could provide a mechanical advantage of n where n is the number of parts of the rope in the pulley mechanism which support the moving block. For example, a block and tackle system with three sheaves or pulley wheels in the upper block and two sheaves in the lower (suspended) block will have five sections of the rope supporting the load giving a mechanical advantage of five. Pulling the rope by five feet with a force of one pound will draw the pulley blocks one foot closer together, raising the load by one foot. The tension on the rope will be the same throughout its length, so that the five sections of the rope between the pulleys, together provide a combined lifting force of five pounds on the lower block. Thus the affect on the load is that the mechanism multiplies the force applied by five but divides the distance moved by five.
  • Similarly, Archimedes was familiar with gearing, which had been mentioned in the writings of Aristotle about wheel drives and windlasses around 330 B.C., and was able to calculate the mechanical advantage provided by the geared mechanisms of simple spur gears. Archimedes is however credited with the invention of the worm gear which not only provided much higher mechanical advantage, it also had the added advantage that the "worm", actually a helical screw, could easily rotate the gear wheel but the gear wheel could not easily, if at all, rotate the worm. This gave the mechanism a ratchet like, or braking, property such that heavy loads would not slip back if the input force was relaxed.
  • It is said that he invented a screw pump, known after him as the Archimedes' Screw, for raising water by means of a hollow wooden pipe containing a close fitting wooden, helical screw on a long shaft turned by a handle at one end. When the other end was placed in the water to be raised and the handle turned, water was carried up the tube by the screw and out at the top. However such devices probably predated Archimedes and were possibly used in the Hanging Gardens of Babylon. The Archimedes' Screw is still used today as a method of irrigation in some developing countries.
  • He also designed winches, windlasses and military machines including catapults, trebuchets and siege engines.
  • It is claimed by some that Archimedes invented the odometer but this is more likely to be the work of Vitruvius who described its working details.
  • Fanciful claims have also been made that he designed gear mechanisms for moving extremely heavy loads, an Iron Claw to lift ships out of the water causing them to break up and a Death Ray to set approaching ships on fire. See more about these claims below.

Archimedes' Mathematics

While Archimedes was famous for his inventions, his mathematical writings were equally important but less well known in antiquity. Mathematicians from Alexandria read and quoted him, but the first comprehensive compilation of his work was not made until Circa. 530 A.D. by Isidore of Miletus.

  • Archimedes was able to use infinitesimals in a way that is similar to modern integral calculus. Through proof by contradiction (reductio ad absurdum), he could give answers to problems to an arbitrary degree of accuracy, while specifying the limits within which the answer lay.
  • Though mathematicians had been aware for many years that the ratio π between the circumference and the diameter of a circle was a constant, there were wide variations in the estimations of its magnitude. Archimedes calculated its value to be 3.1418, the first reasonably accurate value of this constant.
  • He did it by using the method of exhaustion to calculate the circumference of a circle rather than the area and by dividing the circumference by the diameter he obtained the value of π. First he drew a regular hexagon inside a circle and computed the length of its perimeter. Then he improved the accuracy by progressively increasing the number of sides of the polygon and calculating the perimeter of the new polygon with each step. As the number of sides increases, it becomes a more accurate approximation of a circle. At the same time, by circumscribing the circle with a series of polygons outside of the circle, he was able to determine an upper limit for the perimeter of the circle. He found that with a 96 sided polygon the lower and upper limits of π calculated by his method were given by:

    223/71 < π < 22/7

    In modern decimal notation this converts to:

    3.1408 < π < 3.1428

    The value of π calculated by Archimedes is given by the average between the two limits and this is 3.1418 which is within 0.0002 of its true value of 3.1416.

  • More generally, Archimedes calculated the area under a curve by imagining it as a series of very thin rectangles and proving that the sum of the areas of all the rectangles gave a very close approximation to the area under the curve. Using the method of exhaustion he showed that the approximation was neither greater nor smaller than the area of the figure under consideration and therefore it must be equal to the true area. He was thus able to calculate the areas and volumes of different shapes and solids with curved sides. This method anticipated the methods of integral calculus introduced nearly 2000 years later by Gregory, Newton and Leibniz.
  • He was also able to calculate the sum of a geometric progression.
  • He proved that the area of a circle was equal to π multiplied by the square of the radius of the circle (πr2) and that the volume and surface area of sphere are 2/3 of a cylinder with the same height and diameter.
  • Thus he showed that the surface area A of a sphere with radius r is given by: A = 4 π r2 and the volume V of a sphere with radius r is given by: V = 4/3π r3 which he regarded as one of his proudest achievements.

  • He also developed fundamental theorems concerning the determination of the centre of gravity of plane figures.
  • In an attempt to calculate how many grains of sand it would take to fill the Universe, Archimedes devised a number system which he called the Sand Reckoner to represent the very large numbers involved. Based on the largest number then in use called the myriad equal to 10,000 he used the concept of a myriad-myriads equal to 108. He called the numbers up to 108 "first numbers" and called 108 itself the "unit of the second numbers". Multiples of this unit then became the second numbers, up to this unit taken a myriad-myriad times, 108·108=1016. This became the "unit of the third numbers", whose multiples were the third numbers, and so on so that the largest number became (108) raised to the power (108) which in turn is raised to the power (108).

Myths and Reality

As with many great men of antiquity, few if any, contemporary records of Archimedes works remain and his reputation has been embellished by historians writing about him many years after his death, or trashed by artists, ignorant of the scientific principles involved, attempting to illustrate his ideas. This is probably the case with four of the oft quoted anecdotes about his work.

  • It is claimed that Archimedes used a mirror or mirrors on the shore to focus the Sun's rays, the so called Death Rays onto attacking ships to destroy them by setting them on fire. (The Greeks had much more practical incendiary missiles available to them at the time and catapults to throw them long distances)

  • Similarly it is reported that Archimedes used his compound pulley system connected to an Iron Claw suspended from a beam to lift the prows of attacking ships out of the water causing them to break up or capsize and sink. (The ships would have to be almost on the beach, directly in front of the defensive claw, to be in range of these machines.)

  • He was also familiar with geared mechanisms and it was claimed by third century historian, Athenaeus, that Archimedes' systems of winches and pulleys would enable a few men to launch a huge boat into the sea or to carry it on land. These mechanisms were illustrated by Gian Maria Mazzucchelli in his 1737 biography of Archimedes. It is quite clear from the drawings that the wooden gear wheels would have been unable to transmit the power required and the tensile strength of the ropes employed is also questionable.

  • Over the years, in the absence of written records, other artists and illustrators have tried to depict Archimedes devices and mechanisms. Examples of how the artists have imagined these devices are shown in the page about Archimedes' Machines

  • The most widely known anecdote about Archimedes is the Eureka story told two centuries later by the Roman architect and engineer Vitruvius. According to Vitruvius, King Hieron II had supplied a pure gold ingot to a goldsmith charged with making a new crown. The new crown when delivered weighed the same as the ingot supplied but the King wanted Archimedes to determine whether the goldsmith had adulterated the gold by substituting a portion of silver. Archimedes was aware that silver is less dense than gold so he would be able to to determine whether some of the gold had been replaced by silver by checking the density. He had a balance to check the weight, but how could he determine the volume of an intricately designed crown without melting it down or otherwise damaging it?
  • While taking a bath, he noticed that the level of the water in the tub rose as he got in, and realised that this effect could be used to determine the volume of the crown. By immersing the crown in water, the volume of water displaced would equal the volume of the crown. If any of the gold had been replaced by silver or any other less dense metal, then the crown would displace more water than a similar weight of pure gold. EUREKA!!!. It was reported that Archimedes then took to the streets naked, so excited by his discovery that he had forgotten to dress, crying "Eureka!" (Greek: meaning "I have found it!").

    The test was conducted successfully, proving that silver had indeed been mixed in. There is no record of what happened to the goldsmith. It is claimed today that the change in volume would probably have been so small as to be undetectable by the apparatus available to Archimedes at the time.

    There is no question however that he devised a method of measuring the volume of irregularly shaped objects and also understood the principle of buoyancy and its use for comparing the density of the materials used in different objects, but the story of him running naked through the streets is probably apocryphal.

All of these stories probably contain a major element of truth and it would not be surprising that Archimedes was well aware of, and had publicised, the theoretical possibilities involved in these schemes, but whether they could have actually been successfully implemented with the available technology and materials of the day is open to question. The principles were correct but the scale and effectiveness of the devices described in biographies written hundreds of years later was doubtful. There is unfortunately no corroborating evidence to back up these later descriptions of the military exploits. If the naval siege defences had been so successful, why would they not have been subsequently adopted as standard practice and why did they not appear in historical accounts of the battles?

Death of Archimedes

By 215 B.C. Hostilities between Carthage and Rome flared up once more in the second Punic War and in 214 B.C. and Syracuse sided once more with the Carthaginians and so came under siege by the Romans under General Marcus Claudius Marcellus. Archimedes skills in designing military machines and mechanical devices were well known, even to the Romans, and were called upon in the defence of Syracuse during these hostilities.

Greek historian Plutarch (C. 46 – 120 A.D.) gave two accounts of Archimedes' death in 212 B.C. when Roman forces eventually captured the city after a two year siege. The first describes how Archimedes was contemplating a mathematical problem on a diagram he had drawn in the dust on the ground when he was approached by a Roman soldier who commanded him to come and meet General Marcellus who considered the great inventor to be a valuable scientific asset who should not be harmed. But Archimedes declined, saying that he had to finish working on the problem. The soldier was enraged by this, and ran him through with his sword, much to the annoyance of Marcellus.

The second account explains that Archimedes was killed by a soldier while attempting to rob him of his valuable mathematical instruments.

Recent examination of all the accounts by both Carthaginian and Roman historians of the details of Archimedes' death have however reached a different conclusion. As we know, history is often written by the winners. The counter view is that Archimedes' death was the state-sponsored assassination of an enemy of Rome, a key player, whose inventions were vital to the defence of Syracuse. The nations were at war. Why would Archimedes be so oblivious to the danger he was in? Marcellus' feigned sorrow and anger after the event were a cover for his guilt at ordering the death of the World's greatest scientist at the time.

250 B.C. The Baghdad Battery - In 1936 several unusual earthenware jars, dating from about 250 B.C., were unearthed during archeological excavations at Khujut Rabu near Baghdad. A typical jar was 130 mm (5-1/2 inches) high and contained a copper cylinder, the bottom of which was capped by a copper disk and sealed with bitumen or asphalt. An iron rod was suspended from an asphalt stopper at the top of the copper cylinder into the centre of the cylinder. The rod showed evidence of having been corroded with an acidic agent such as wine or vinegar. 250 BC corresponds to the Parthian occupation of Mesopotamia (modern day Iraq) and t jars were held in Iraq's State Museum in Baghdad. (Baghdad was not founded until 762 A.D.) 1938 they were examined by German archeologist Wilhelm König who concluded that they were Galvanic cells or batteries supposedly used for gilding silver by electroplating. A mysterious anachronism. Backing up his claim, König also found copper vases plated with silver dating from earlier periods in the Baghdad Museum and other evidence of (electro?)plated articles from Egypt. Since then, several replica batteries have been made using various electrolytes including copper sulphate and grape juice generating voltages from half a Volt to over one Volt and they have successfully been used to demonstrate the electroplating of silver with gold. One further, more recent, suggestion by Paul T. Keyser a specialist in Neat Eastern Studies from the University of Alberta is that the galvanic cells were used for analgesia. There is evidence that electric eels had been used to numb an area of pain, but quite how that worked with such a low voltage battery is not explained. Apart from that, no other compelling explanation of the purpose of these artifacts has been proposed and the enigma still remains.

Despite warnings about the safety of these priceless articles before the 2003 invasion of Iraq, they were plundered from the museum during the war and their whereabouts is now unknown.

A nice and oft repeated story but there is a counter view about their purpose.

The Parthians were nomadic a nomadic tribe of skilled warriors and not noted for their scientific achievements. The importance of such an unusual electrical phenomenon seems to have gone completely unrecorded within the Parthian and contemporary cultures and then to have been completely forgotten despite extensive historical records from the period.

There are also some features about the artifacts themselves which do not support the battery theory. The asphalt completely covers the copper cylinder, electrically insulating it so that no current could be drawn without modifying the design and no wires, conductors, or any other sort of electrical equipment associated with the artifacts have been found. Furthermore the asphalt seal forms a perfect seal for preventing leakage of the electrolyte but it would be extremely inconvenient for a primary galvanic cell which would require frequent replacement of the electrolyte. As an alternative explanation for these objects, it has been noted that they resemble storage vessels for sacred scrolls. It would not be at all surprising if any papyrus or parchment inside had completely rotted away, perhaps leaving a trace of slightly acidic organic residue.

240 B.C. Greek mathematician Eratosthenes(276-194 B.C.) of Cyrene (now called Shahhat, Libya), the third chief librarian at the Library of Alexandria and contemporary of Archimedes calculated the Circumference of the Earth. Considering the tools and knowledge available at the time, Eratosthenes results are truly brilliant. Equipped with only a stick, he did not even need to leave Alexandria to make this remarkable breakthrough. Not only did he know that the Earth was spherical, 1700 years before Columbus was born, he also knew how big it was to an accuracy within 1.5%. See Eratosthenes Method and Calculation.

He invented the discipline of geography including the terminology still used today and created the first map of the world incorporating parallels and meridians, (latitudes and longitudes) based on the available geographical knowledge of the era. He was also the first to calculate the tilt of the Earth's axis (again with remarkable accuracy) and he deduced that the calendar year was 365 1/4 days long and was first to suggest that every four years there should be a leap year of 366 days.

Eratosthenes also devised a way of finding prime numbers known as the sieve. Instead of using trial division to sequentially test each candidate number for divisibility by each prime which is a very slow process, his system marks as composite (i.e. not prime) the multiples of each prime, starting with the multiples of 2, then 3 and continues this iteratively so that they can be separated out. The multiples of a given prime are generated as a sequence of numbers starting from that prime, with constant difference between them which is equal to that prime.

220-206 B.C. The magnetic compass was invented by the Chinese during the Qin (Chin) Dynasty, named after China's first emperor Qin Shi Huang di, the man who built the wall. It was used by imperial magicians mostly for geomancy (Feng Shui and fortune telling) but the "Mighty Qin's" military commanders were supposed to be the first to use a lodestone as a compass for navigation. Chinese compasses point south.

See more about Chinese Inventions.

206 B.C. - 220 A.D. During the Han Dynasty, Chinese historian Ban Gu recorded in his Book of Han the existence of pools of "combustible water", most likely petroleum, in what is now China's Shaanxi province. During the same period, in Szechuan province, natural gas was also recovered from what they called "fire wells" by deep drilling up to several hundred feet using percussion drills with cast iron bits. These fuels were used for domestic heating and for extracting metals from their ores (pyrometallurgy), for breaking up rocks as well as for military incendiary weapons. The heavy oil was also distilled to produce paraffin (kerosene) for use in decorative oil lamps from the period which have been discovered.

Percussion drilling involves punching a hole into the ground by repeatedly raising and dropping a heavy chisel shaped tool bit into the bore hole to shatter the rock into small pieces which can be removed. The drill bit is raised by a cable and pulley system suspended from the top of a wooden tower called a derrick.

The fuels were later named in Chinese as shíyóu rock oil by Shen Kuo just as the word petroleum is derived from the latin petra rock and oleum oil.

It was over 2000 years before the first oil well was drilled by Edwin Drake in the USA and he used the same percussion drilling method as the Chinese.

See more about Chinese Inventions.

140 - 87 B.C. Paper was first produced in China in the second century B.C.. Made by pounding and disintegrated hemp fibres, rags and other plant fibres in water followed by drying on a flat mould, the paper was thick and coarse and surprisingly it was not used for writing but for clothing, wrapping, padding and personal hygiene. The oldest surviving piece of paper was found in a tomb near Xian and dates from between 140 B.C. to 87 B.C. and is inscribed with a map.

The first paper found with writing on it was discovered in the ruins of an ancient watch tower and dates from 105 A.D. The development of this finer paper suitable for writing is attributed to Cai Lun, a eunuch in the Imperial court during the Han dynasty (202 B.C. - A.D. 220).

Paper was an inexpensive new medium which provided a simple means of communicating accurately with others who were not present without the danger of "Chinese whispers" corrupting the message, but more importantly, it enabled knowledge to be spread to a wider population or recorded for use by future generations. A simple invention which, like the printing press, brought enormous benefits to society.

See more about Chinese Inventions.

27 B.C. - 5th Century A.D. The Roman Empire. The Romans were great plumbers but poor electricians.

The Romans were deservedly renowned for their civil engineering - buildings, roads, bridges, aqueducts, central heating and baths. Surprisingly however, in 500 years, they didn't advance significantly on the legacies of mathematics and scientific theories left to them by the Greeks. Fortunately, the works of the Greek philosophers and mathematicians were preserved by Arab scholars who translated them into Arabic.

Circa 15 B.C. Some time between 27 B.C and 15 B.C. Roman architect and military engineer, Marcus Vitruvius Pollio, completed "De Architectura" or "On Architecture: The Ten Books on Architecture". It is a comprehensive manual for architects covering the principles of architecture, education and training, town planning, environment, structures, building materials and construction methods, design requirements for buildings intended for different purposes, proportions, decorative styles, plans for houses, heating, acoustics, pigments, hydraulics, astronomy and a ranges of machinery and instruments.

His philosophies about architecture are summed up in the Vitruvian Virtues that a structure must exhibit the three qualities of firmitas, utilitas, venustas - meaning that it must be solid, useful and beautiful.

Included in Book 10 of the study are designs for military and hydraulic machines, including pulleys and hoists and designs for trebuchets, water wheels and armoured vehicles which have had an undeniable influence on the inventions of Leonardo da Vinci. See more about Vitruvius water wheels.

Amongst Vitruvius' designs are instructions for the design of an odometer which he called a "hodometer". It consisted of a cart with a separate, large wheel of known circumference mounted in a frame. The large wheel was connected through the intermediate gear wheel of a reduction gear mechanism to a horizontal disk with a series of holes around its rim each containing a small pebble. A single hole in the housing of the horizontal disk allowed a pebble to fall through into a container below when it arrived above the hole. As the cart was pushed along the ground, one pebble would fall into the container for each revolution of the intermediate gear wheel. The distance traveled could be calculated by counting the number of pebbles in the container and multiplying by the circumference of the large wheel and the gear ratio. Vitruvius also proposed a marine version of his device in which the distance was calculated from the rotation of paddles.

There are some who attribute the design of the odometer to Archimedes, but there is no strong evidence to support this.

Unfortunately none of the original illustrations from "De Architectura" have survived. Nevertheless the books have deeply influenced classical architects from the Renaissance through to the twentieth century. He was perhaps a little too influential though, through no fault of his own, since his style was so sublime that it captured public taste, stifling further innovation and generations of architects merely copied his ideas rather than developing alternative styles of their own.

Vitruvius has been called the world's first engineer to be known by name.

1 B.C.

1 A.D.

Circa 50 A.D. In the first century A.D. several spectacular aqueducts were built by Roman Engineers and though many of them are still standing and in some cases still in use, there are unfortunately no records of who actually designed and built them. Two which stand out are the Pont du Gard near Nimes in France, the other at Segovia in Spain.

(See pictures of these two Roman Aqueducts)

In the absence of records the design and construction of the Pont du Gard has been attributed to Marcus Agrippa, the adopted son-in-law of Emperor Augustus at around the year 19 B.C. However recent excavations and coins depicting the Emperor Claudius (41-54 A.D.) found at the site suggest that the construction may have taken place between 40 and 60 A.D. The aqueduct supplied Nimes with water and is nearly 30 miles (50 kilometres) long. The section over the river Gard has arches at three levels and is 900 feet (275 metres) long and 160 feet (49 metres) high. The top level contains a channel 6 feet (1.8 metres) high and 4 feet (1.2 metres) wide with a gradient of 0.4 per cent to carry the water. The bottom level carries a roadway. The three levels were built in dressed stone without mortar.

Some researchers have estimated that the Segovia aqueduct was started in the second half of the 1st Century A.D. and completed in the early years of the 2nd Century, during the reign of either Emperor Vespasian (69-79 A.D.) or Nerva (96-98 A.D.). Others have suggested it was started under Emperor Domitian (81-96 A.D.) and probably completed under Trajan (98-117 A.D.). The aqueduct brought water to Segovia from the Frio River 10 miles (16 km) away. Its maximum height is 93 ft 6 in (28.5 metres), including nearly 19 ft 8 in (6 metres) of foundations and it is constructed from 44 double arches, 75 single arches and another four single arches giving a total of 167 arches. The bridge section of the aqueduct is 2240 feet (683 meters) long and changes direction several times. Like the Pont du Gard, it was built from dressed stone without mortar.

Circa 60 A.D. Greek mathematician Hero of Alexandria conceived the idea of a reaction turbine though he didn't call it that. He called it an Aeolipile (Aeolus - Greek God of the Wind) (Pila Latin - Ball) or the Sphere of Aeolus. It was a hollow sphere containing a small amount of water, free to rotate between two pivot points. When heated over a flame the steam from the boiling water escaped through two tangential nozzles in jets which caused the sphere to rotate at high speed. See diagram of Hero's Aeolipile.

Alternative designs show the water boiled in a separate chamber being fed through a hollow pipe into the sphere through one of the pivots.

It has been suggested that this device was used by priests to perform useful work such as opening temple doors and moving statues to impress gullible worshippers but no physical evidence remains and these ideas were never developed and the aeolipile remained as a toy.

Hero is also credited as being the first to propose a formal way of calculating square roots.

See more about Reaction Turbines.

See more about Steam Engines


150 A.D. Some time between 150 A.D. and 160 A.D. Greek astronomer and mathematician Claudius Ptolemaeus, Ptolemy a Roman citizen of Alexandria, (not one of the Ptolomaic Kings) published the Almagest "The Great Book". In it he summarised the all known information about astronomy and the mathematics which supported the theories. For over a thousand years it was the accepted explanation of the workings of the Universe. Unfortunately it was based on a geocentric model with uniform circular motions of the Sun and planets around the Earth. Where this ideal motion did not fit the observed movements, the anomalies were explained by the concept of equants with the planets moving in smaller epicyclic orbits superimposed on the major orbit. It was not until Copernicus came along 1400 years later that Ptolemy's theory was seriously challenged. The Almagest was however a major source of information about Greek trigonometry.

In a similar vein to the Almagest, Ptolemy also published Geographia which summarised all that was known at the time about the World's geography as well as the projections used to create more accurate maps.

200 Greek philosopher Claudius Galen from Pergamum, Asia Minor, physician to five Roman emperors and surgeon to the Roman gladiators, was the first of many to claim therapeutic powers of magnets and to use them in his treatments. Galen carried out controlled experiments to support his theories and was the first to conclude that mental actively occurred in the brain rather than the heart, as Aristotle had suggested. Like many ancient philosophers his authority was virtually undisputed for many years after his death, thus discouraging original investigation and hampering medical progress until the 16th century.

But see Vesalius.

400 Greek scholar Hypatia of Alexandria took up her position as head of the Platonist school at the great Library of Alexandria, (in the period between its third and its fourth and final sacking), where she taught mathematics, astronomy and philosophy. The first recorded woman in science, she is considered to be the inventor of the hydrometer, called the aerometer by the Greeks. Claims that she also invented the planar astrolabe are probably not true since there is evidence that the astrolabe dates from 200 years earlier, but her mathematician father Theon of Alexandria had written a treatise on the device and she no doubt lectured about its use for calculating the positions of the Sun, Moon and stars.

Hypatia still held pagan beliefs at a time when the influence of Christianity was beginning to grow and unfortunately her science teachings were equated with the promotion of paganism. In 415 she was attacked by a Christian mob who stripped her, dragged her through the streets, killed her and cut her to pieces using oyster shells. Judging from her appearance as depicted by Victorian artists, it's no surprise that the local monks were outraged. See Hypatia 1885 by Charles William Mitchell.

426 Electric and magnetic phenomena were investigated by St Augustine who is said to have been "thunderstruck" on witnessing a magnet lift a chain of rings. In his book "City of God" he uses the example of magnetic phenomena to defend the idea of miracles. Magnetism could not be explained but it manifestly existed, so miracles should not be dismissed just because they could not be explained.

619 In 1999, archaeologists at Nendrum on Mahee Island in Ireland investigating what they thought to be a stone tidal pond used for catching fish uncovered two stone built tidal mills with a millstones and paddle blades dating from 619 AD and 787 AD. Several tidal mills were built during the Roman occupation of England for grinding grain and corn. They operated by storing water behind a dam during high tide, and letting it out to power the mill after the tide had receded and were the forerunners of the modern schemes for capturing tidal energy.

645 Xuan Zhuang the great apostle of Chinese Buddhism returned to China from India with Buddhist images and more than 650 Sanskrit Buddhist scriptures which were reproduced in large quantities giving impetus to the refinement of traditional methods of printing using stencils and inked squeezes first used by the Egyptians. A pattern of rows of tiny dots was made in a sheet of paper which was pressed down on top of a blank sheet and ink was forced through the holes. Later stencils developed by the Chinese and Japanese used human hair or silk thread to tie delicate isolated parts into the general pattern but there was no fabric backing to hold the whole image together. The stencil image was printed using a large soft brush, which did not damage the delicate paper pattern or the fine ties. These printing techniques of composite inked squeezes and stencils foreshadowed modern silk screen printing which was not patented until 1907.

700 - 1100 Islamic Science During Roman times, the flame of Greek science was maintained by Arab scholars who translated Greek scientific works into Arabic. From 700 A.D. however, when most of Europe was still in the Dark Ages, scientific developments were carried forward on a broad front by the Muslim world with advances in astronomy, mathematics, physics, chemistry and medicine. Chemistry (Arabic Al Khimiya "pour together", "weld") was indeed the invention of the Muslims who carried out pioneering work over three centuries putting chemistry to practical uses in the refinement of metals, dyeing, glass making and medicine. In those days the notion of alchemy also included what we would today call chemistry. Among the many notable muslim scientists from this period were Jabir Ibn Haiyan, Al-Khawarizmi and Al-Razi.

By the tenth century however, according to historian Toby Huff, the preeminence of Islamic science began to wane. It had flourished in the previous three centuries while Muslims were in the minority in the Islamic regions however, starting in the tenth century, widespread conversion to Islam took place and as the influence of Islam increased, so the tolerance of alternative educational and professional institutions and the radical ideas of freethinkers decreased. They were dealt a further blow in 1485, thirty five years after the invention of the printing press, when the Ottoman Sultan Byazid II issued an order forbidding the printing of Arabic letters by machines. Arabic texts had to be translated into Latin for publication and this no doubt hampered both the spread of Islamic science and ideas as well as the influence of the outside world on the Islamic community. This prohibition of printing was strictly enforced by subsequent Ottoman rulers until 1728 when the first printing press was established in Istanbul but due to objections on religious grounds it closed down in 1742 and the first Koran was not printed in Istanbul until 1875. Meanwhile in 1734 Deacon Abdalla Zakhir of the Greek Catholic Maronite Monastery of Saint John Sabigh in the Lebanon managed to establish the first independent Arabic printing press.

Islam was not alone in banning the dissemination of subversive or inconvenient ideas. Henry VIII in 1529, aware of the power of the press, became the first monarch to publish a list of banned books though he did not go so far as banning printing. He was later joined by others. In 1632 Galileo's book "Dialogue Concerning the Two Chief World Systems", in which he asserted that the Earth revolved around the Sun rather than the other way round, was placed by Pope Urban VIII on the index of banned books and Galileo was placed under house arrest. Despite these setbacks, European scientific institutions overcame the challenges by the church, taking over the flame carried by the Arabs and the sixteenth and seventeenth centuries became the age of Scientific Revolution in Europe.

776 Persian chemist Abu Musa Jabir Ibn Haiyan (721-815), also known as Geber, was the first to put chemistry on a scientific footing, laying great emphasis on the importance of formal experimentation. In the period around 776 A.D. he perfected the techniques of crystallisation, distillation, calcination, sublimation and evaporation and developed several instruments including the alembic (Arabic al-ambiq, "still") which simplified the process of distillation, for carrying them out. He isolated or prepared several chemical compounds for the first time, notably nitric, hydrochloric, citric and tartaric acids and published a series of books describing his work which were used as classic works on alchemy until the fourteenth century. Unfortunately the books were added to, under Geber's name, by various translators in the intervening period leading to some confusion about the extent of Geber's original work.

830 Around the year 830, Baghdad born mathematician Mohammad Bin Musa Al-Khawarizmi (770-840) published "The Compendium Book on Calculation by Completion and Balancing" in which he introduced the principles of algebra (Arabic Al-jabr "the reduction" i.e. of complicated relationships to a simpler language of symbols) which he developed for solving linear and quadratic equations. He also introduced the decimal system of Hindu-Arabic numerals to Europe as well as the concept of zero, a mathematical device at the time unknown in Europe used to Roman numerals. Al-Khawarizmi also constructed trigonometric tables for calculating the sine functions. The word algorithm (algorizm) is named after him.

850 Historian of Chinese inventions, Joseph Needham, identified 850 as the date of the first appearance of what the Chinese called the "fire chemical" or what we would now call gunpowder. Around that year, a book attributed to Chinese alchemist Cheng Yin warns of the dangerous incendiary nature of mixtures containing saltpetre (potassium nitrate), and sulphur, both essential components of gunpowder. Such chemicals mixed with various other substances including carbonaceous materials and arsenic had been used in various concentrations by alchemists since around 300 A.D. when Ko Hung proposed these mixtures in recipes for transforming lead into gold and mercury into silver while others later used them in attempts to create a potion of immortality.

After Cheng Yin's warning, similar mixtures were soon developed to produce flares and fireworks as well as military ordnance including burning bombs and fuses to ignite flame throwers burning petrol (gasoline). The first example of a primitive gun called a "fire arrow" appeared in 905, and in 994, arrows tipped with burning "fire chemicals" were used to besiege the city of Tzu-t'ung.

Most of these military applications were merely incendiary devices rather than explosives since they did not yet contain enough saltpetre (75%) to detonate. It was not until 1040 that the full power of the saltpetre rich mixture was discovered and the first true formula for gunpowder was published by Tseng Kung-Liang. After that, true explosive devices were developed including cannon and hand grenades and land mines.

Around 1150 it was realised that an arrow could be made to fly without the need for a bow by attaching to the shaft, a bamboo tube packed with a burning gunpowder mix. This led to the development of the rocket which was born when larger projectiles were constructed from the bamboo sticks alone without the arrows. A text from around that time describes how the combustion efficiency and hence the rocket thrust could be improved by creating a cavity in the propellant along the centre line of the rocket tube to maximise the burning surface - a technique still used in solid fuelled rockets today.

In 1221 Chinese chronicler Chao Yu-Jung recorded the first use of bombs which we would recognise today, with cast iron casings packed with explosives, which created deadly flying shrapnel when they exploded. They were used to great effect by a special catapult unit in Genghis Khan's Mongol army and by the Chinese Jin forces to defeat their Song enemies in the 1226 siege of Kaifeng.

See more about Nobel and Explosives.

920 Around the year 920, Persian chemist Mohammad Ibn Zakariya Al-Razi (865-925), known in the West as Rhazes, carried on Geber's work and prepared sulphuric acid, the "work horse" of modern chemistry and a vital component in the world's most common battery. He also prepared ethanol, which was used for medicinal applications, and described how to prepare alkali (Al-Qali, the salt work ashes, potash) from oak ashes. Al-Razi published his work on alchemy in his "Book of Secrets". The precise amounts of the substances he specified in his recipes demonstrates an understanding of what we would now call stoichiometry.

Several more words for chemicals are derived from their Arabic roots including alcohol (Al Kuhl" "essence", usually referring to ethanol) as well as arsenic and borax.


1040 Thermoremanent magnetisation described in the Wu Ching Tsung Yao "Compendium of Military Technology" in China. Compass needles were made by heating a thin piece of iron, often in the shape of a fish, to a temperature above the Curie Point then cooling it in line with the Earth's magnetic field.

1041 Between 1041 and 1048 Chinese craftsman Pi Sheng produced the first printing press to use moveable type. Although his designs achieved widespread use in China, it was another four hundred years before the printing press was "invented" by Johann Gutenberg in Europe.

See more about Chinese Inventions.

1086 During the Song Dynasty (960-1127), Chinese astronomer, cartographer and mathematician Shen Kuo, in his Dream Pool Essays, describes the compass and its use for navigation and cartography as well as China's petroleum extraction and Pi Sheng's printing technique.

See more about Chinese Inventions.

1190 The magnetic compass "invented" in Europe 1400 years after the Chinese. Described for the first time in the west by a St Albans monk Alexander Neckam in his treatise De Naturis Rerum.

1250's Italian theologian St Thomas Aquinas stands up for the cause of "reason" reconciling the philosophy of Aristotle with Christian doctrine. Challenging Aristotle now became a challenge to the Church.

See also the Scientific Revolution

1269 Petrus Peregrinus de Marincourt, (Peter the Pilgrim) a French Crusader, used a compass to map the magnetic field of a lodestone. He discovered that a magnet had two magnetic poles, North and South and was the first to describe the phenomena of attraction and repulsion. He also speculated that these forces could be harnessed in a machine.

1285 The earliest record of a mechanical clock with an escapement or timing control mechanism is a reference to a payment to a clock keeper at (the original) St. Paul's in London. The invention of the verge and foliot escapement was an important breakthrough in measuring the passage of time allowing the development of mechanical timepieces.

The name verge comes from the Latin virga, meaning stick or rod. (See picture and explanation of the Verge Escapement)

The inventor of the verge escapement is not known but we know that it dates from 13th century Europe, where it was first used in large tower clocks which were built in town squares and cathedrals. The earliest recorded description of an escapement is in Richard of Wallingford's 1327 manuscript Tractatus Horologii Astronomici on the clock he built at the Abbey of St. Albans. It was not a verge, but a more complex variation.

For over 200 years the verge was the only escapement used in mechanical clocks until alternative escapements started to appear in the 16th century and it was 350 years before the more accurate pendulum clock was invented by Huygens.

1350 Around this time the first blast furnaces for smelting iron from its ore begin to appear in Europe, 1800 years after the Chinese were using the technique.

See more about Cast Iron and Steel.

1368-1644 China's Ming dynasty. When the Ming dynasty came into power, China was the most advanced nation on Earth. During the Dark Ages in Europe, China had already developed cast iron, the compass, gunpowder, rockets, paper, paper money, canals and locks, block printing and moveable type, porcelain, pasta and many other inventions centuries before they were "invented" by the Europeans. From the first century B.C. they had also been using deep drilling to extract petroleum from the underlying rocks. They were so far ahead of Europe that when Marco Polo described these wondrous inventions in 1295 on his return to Venice from China he was branded a liar. China's innovation was based on practical inventions founded on empirical studies, but their inventiveness seems to have deserted them during the Ming dynasty and subsequently during the Qing (Ching) dynasty (1644 - 1911). China never developed a theoretical science base and both the Western scientific and industrial revolutions passed China by. Why should this be?

It is said that the answer lies in Chinese culture, to some extent Confucianism but particularly Daoism (Taoism) whose teachings promoted harmony with nature whereas Western aspirations were the control of nature. However these conditions existed before the Ming when China's innovation led the world. A more likely explanation can be found in China's imperial political system in which a massive society was rigidly controlled by all-powerful emperors through a relatively small cadre of professional administrators (Mandarins) whose qualifications were narrowly based on their knowledge of Confucian ideals. If the emperor was interested in something, it happened, if he wasn't, it didn't happen.

The turning point in China's technological dominance came when the Ming emperor Xuande came to power in 1426. Admiral Zheng He, a muslim eunuch, castrated as a boy when the Chinese conquered his tribe, had recently completed an audacious voyage of exploration on behalf of a previous Ming emperor Yongle to assert China's control of all of the known world and to extract tributary from its intended subjects. But his new master considered the benefits did not justify the huge expense of Zheng's fleet of 62 enormous nine masted junks and 225 smaller supply ships with their 27,000 crew. The emperor mothballed the fleet and henceforth forbade the construction of any ships with more than two masts, curbing China's aspirations as a maritime power and putting an end to its expansionist goals, a xenophobic policy which has lasted until modern times.

The result was that during both the Ming and the Qing dynasties a succession of complacent, conservative emperors cocooned in prodigious, obscene wealth, remote even from their own subjects, lived in complete isolation and ignorance of the rest of the world. Foreign influences, new ideas, and an independent merchant class who sponsored them, threatened their power and were consequently suppressed. By contrast the West was populated by smaller, diverse and independent nations competing with each other. Merchant classes were encouraged and innovation flourished as each struggled to gain competitive or military advantage.

Times have changed. Currently China is producing two million graduates per year, sixty percent of which are in science and technology subjects, three times as many as in the USA.

After Japan, China is the second largest battery producer in the world and growing fast.

1450 German goldsmith and calligrapher Johann Genstleisch zum Gutenberg from Mainz invented the printing press, considered to be one of the most important inventions in human history. For the first time knowledge and ideas could be recorded and disseminated to a much wider public than had previously been possible using hand written texts and its use spread rapidly throughout Europe. Intellectual life was no longer the exclusive domain of the church and the court and an era of enlightenment was ushered in with science, literature, religious and political texts becoming available to the masses who in turn had the facility to publish their own views challenging the status quo. It was the ability to publish and spread one's ideas that enabled the Scientific Revolution to happen. Nowadays the Internet is bringing about a similar revolution.

Although it was new to Europe, the Chinese had already invented printing with moveable type four hundred years earlier but, because of China's isolation, these developments never reached Europe.

Gutenberg printed Bibles and supported himself by printing indulgences, slips of paper sold by the Catholic Church to secure remission of the temporal punishments in Purgatory for sins committed in this life. He was a poor businessman and made little money from his printing system and depended on subsidies from the Archbishop of Mainz. Because he spent what little money he had on alcohol, the Archbishop arranged for him to be paid in food and lodging, instead of cash. Gutenberg died penniless in 1468.

1474 The first patent law, a statute issued by the Republic of Venice, provided for the grant of exclusive rights for limited periods to the makers of inventions. It was a law designed more to protect the economy of the state than the rights of the inventor since, as the result of its declining naval power, Venice was changing its focus from trading to manufacturing. The Republic required to be informed of all new and inventive devices, once they had been put into practice, so that they could take action against potential infringers.

1478 After 10 years working as an apprentice and assistant to successful Florentine artist Andrea del Verrocchio at the court of Lorenzo de Medici in Florence, at the age of 26 Leonardo da Vinci left the studio and began to accept commissions on his own.

One of the most brilliant minds of the Italian Renaissance, Leonardo was hugely talented as an artist and sculptor but also immensely creative as an engineer, scientist and inventor. The fame of his surviving paintings has meant that he has been regarded primarily as an artist, but his scientific insights were far ahead of their time. He investigated anatomy, geology, botany, hydraulics, acoustics, optics, mathematics, meteorology, and mechanics and his inventions included military machines, flying machines, and numerous hydraulic and mechanical devices.

He lived in an age of political in-fighting and intrigue between the independent Italian states of Rome, Milan, Florence, Venice and Naples as well as lesser players Genoa, Siena, and Mantua ever threatening to degenerate into all out war, in addition to threats of invasion from France. In those turbulent times da Vinci produced a series of drawings depicting possible weapons of war during his first two years as an independent. Thus began a lifelong fascination with military machines and mechanical devices which became an important part of his expanding portfolio and the basis for many of his offers to potential patrons, the heads of these belligerent, or fearful, independent states.

Despite his continuing interest in war machines, he claimed he was not a war monger and he recorded several times in his notebooks his discomfort with designing killing machines. Nevertheless, he actively solicited such commissions because by then he had his own pupils and needed the money to pay them.

Most of Leonardo's designs were not constructed in his lifetime and we only know about them through the many models he made but mostly from the 13,000 pages of notes and diagrams he made in which he recorded his scientific observations and sketched ideas for future paintings, architecture, and inventions. Unlike academics today who rush into publication, he never published any of his scientific works, fearing that others would steal his ideas. Patent law was still in its infancy and difficult, if not impossible, to enforce. Such was his paranoia about plagiarism that he even wrote all of his notes, back to front, in mirror writing, sometimes also in code, so he could keep his ideas private. He was not however concerned about keeping the notes secret after his death and in his will he left all his manuscripts, drawings, instruments and tools to his loyal pupil, Francesco Melzi with no objection to their publication. Melzi expected to catalogue and publish all of Leonardo's works but he was overwhelmed by the task, even with the help of two full-time scribes, and left only one incomplete volume, "Trattato della Pintura" or "Treatise on Painting", about Leonardo's paintings before he himself died in 1570. On his death the notes were inherited by his son Orazio who had no particular interest in the works and eventually sections of the notes were sold off piecemeal to treasure seekers and private collectors who were interested more in Leonardo's art rather than his science.

Because of his secrecy, his contemporaries knew nothing of his scientific works which consequently had no influence on the scientific revolution which was just beginning to stir. It was about two centuries before the public and the scientific community began gradually to get access to Leonardo's scientific notes when some collectors belatedly allowed them to be published or when they ended up on public display in museums where they became the inspiration for generations of inventors. Unfortunately, only 7000 pages are known to survive and over 6000 pages of these priceless notebooks have been lost forever. Who knows what wisdom they may have contained?

Leonardo da Vinci is now remembered as both "Leonardo the Artist" and "Leonardo the Scientist" but perhaps "Leonardo the Inventor" would be more apt as we shall see below.

Leonardo the Artist

It would not do justice to Leonardo to mention only his scientific achievements without mentioning his talent as a painter. His true genius was not as a scientist or an artist, but as a combination of the two: an "artist-engineer".

He did not sign his paintings and only 24 of his paintings are known to exist plus a further 6 paintings whose authentication is disputed. He did however make hundreds of drawings most of which were contained in his copious notes.

  • The "Treatise on Painting"
  • This was the volume of Leonardo's manuscripts transcribed and compiled by Melzi. The engravings needed for reproducing Leonardo's original drawings were made by another famous painter, Nicolas Poussin. As the title suggests it was intended as technical manual for artists however it does contain some scientific notes about light, shade and optics in so far as they affect art and painting. For the same reason it also contains a small section of Leonardo's scientific works about anatomy. The publication of this volume in 1651 was the first time examples of the contents of Leonardo's notebooks were revealed to the world but it was 132 years after his death. The full range of his "known" scientific work was only made public little by little many years later.

Leonardo was one of the world's greatest artists, the few paintings he made were unsurpassed and his draughtsmanship had a photographic quality. Just seven examples of his well known artworks are mentioned here.

  • Paintings
    • The "Adoration of the Magi" painted in 1481.
    • The "Virgin of the Rocks" painted in 1483.
    • "The Last Supper" a large mural 29 feet long by 15 feet high (8.8 m x 4.6 m) started in 1495 which took him three years to complete.
    • The "Mona Lisa" (La Gioconda) painted in 1503.
    • "John the Baptist" painted in 1515.
  • Drawings
    • The "Vitruvian Man" as described by the Roman architect Vitruvius was drawn in 1490, showing the correlation between the proportions of the ideal human body with geometry, linking art and science in a single work.
    • Illustrations for mathematician Fra Luca Pacioli's book "De divina proportione" (The Divine Proportion), drawn in 1496. See more about The Divine Proportion.

Leonardo the Scientist

The following are some examples of the extraordinary breadth of da Vinci's scientific works

  • Military Machines
  • After serving his apprenticeship with Verrocchio, Leonardo had a continuous flow of military commissions throughout his working life.

    In 1481 he wrote to Ludovico Sforza, Duke of Milan with a detailed C. V. of his military engineering skills, offering his services as military engineer, architect and sculptor and was appointed by him the following year. In 1502 the ruthless and murderous Cesare Borgia, illegitimate son of Pope Alexander VI and seducer of his own younger sister (Lucrezia Borgia), appointed Leonardo as military engineer to his court where he became friends with Niccolo Machiavelli, Borgia's influential advisor. In 1507 some time after France had invaded and occupied Milan he accepted the post of painter and engineer to King Louis XII of France in Milan and finally in 1517 he moved to France at the invitation of King Francoise I to take up the post of First Painter, Engineer and Architect of the King. These commissions gave Leonardo ample scope to develop his interest in military machines.

    Leonardo designed war machines for both offensive and defensive use. They were designed to provide mobility and flexibility on the battlefield which he believed was crucial to victory. He also designed machines to use gunpowder which was still in its infancy in the fifteenth century.

    His military inventions included:

    • Mobile bridges including drawbridges and a swing bridge for crossing moats, ditches and rivers. His swing bridge was a cantilever design with a pivot on the river bank a counterweight to facilitate manoeuvring the span over the river. It also had wheels and a rope-and-pulley system which enabled easy transport and quick deployment.
    • Siege machines for storming walls.
    • Chariots with scythes mounted on the sides to cut down enemy troops.
    • A giant crossbow intended to fire large explosive projectiles several hundred yards.
    • Trebuchets - Very large catapults, based on releasing mechanical counterweights, for flinging heavy projectiles into enemy fortifications.
    • Bombards - Short barrelled, large-calibre, muzzle-loading, heavy siege cannon or mortars, fired by gunpowder and used for throwing heavy stone balls. The modern replacement for the trebuchet. Leonardo's design had adjustable elevation. He also envisaged exploding cannonballs, made up from several smaller stone cannonballs sewn into spherical leather sacks and designed to injure and kill many enemies at one time. We would now call these cluster bombs.
    • Springalds - Smaller, more versatile cannon, for throwing stones or Greek fire, with variable azimuth and elevation adjustment so that they could be aimed more precisely.
    • A series of guns and cannons with multiple barrels. The forerunners of machine guns.
    • They included a triple barrelled cannon and an eight barrelled gun with eight muskets mounted side by side as well as a 33 barrelled version with three banks of eleven muskets designed to enable one set of eleven guns to be fired while a second set cooled off and a third set was being reloaded. The banks were arranged in the form of a triangle with a shaft passing through the middle so that the banks could be rotated to bring the loaded set to the top where it could be fired again.

    • A four wheeled armoured tank with a heavy protective cover reinforced with metal plates similar to a turtle or tortoise shell with 36 large fixed cannons protruding from underneath. Inside a crew of eight men operating cranks geared to the wheels would drive the tank into battle. The drawing in Leonardo's notebook contains a curious flaw since the gearing would cause the front wheels to move in the opposite direction from the rear wheels. If the tank was built as drawn, it would have been unable to move. It is possible that this simple error would have escaped Leonardo's inventive mind but it is also suggested that like his coded notes, it was a deliberate fault introduced to confuse potential plagiarists. The idea that this armoured tank loaded with 36 heavy cannons in such a confined space could be both operated and manoeuvred by eight men is questionable.
    • Automatic igniting device for firearms.
  • Marine Warfare Machines and Devices
  • Leonardo also designed machines for naval warfare including:

    • Designs for a peddle driven paddle boat. The forerunner of the modern pedalo.
    • Hand flippers and floats for walking on water.
    • Diving suit to enable enemy vessels to be attacked from beneath the water's surface by divers cutting holes below the boat's water line. It consisted of a leather diving suit equipped with a bag-like helmet fitting over the diver's head. Air was supplied to the diver by means of two cane tubes attached to the headgear which led up to a cork diving bell floating on the surface.
    • A double hulled ship which could survive the exterior skin being pierced by ramming or underwater attack, a safety feature which was eventually adopted in the nineteenth century.
    • An armoured battleship similar to the armoured tank which could ram and sink enemy ships.
    • Barrage cannon - a large floating circular platform with 16 canons mounted around its periphery. It was powered and steered by two operators turning drive wheels geared to a large central drive wheel connected to paddles for propelling it through the water. Others operators fired the cannons.
  • Flying Machines
  • Leonardo studied the flight of birds and after the legendary Icarus was one of the first to attempt to design human powered flying machines, recording his ideas in numerous drawings. A step up from Chinese kites.

    His drawings included:

    • A design for a parachute. The world's first.
    • Various gliders
    • Designs for wings intended to carry a man aloft, similar to scaled up bat wings.
    • Human powered flying machines known as ornithopters, (from Greek ornithos "bird" and pteron "wing"), based on flapping wings operated by means of levers and cables.
    • A helical air screw with its central shaft powered by a circular human treadmill intended to lift off and fly like a modern helicopter.
  • Civil Works
  • Leonardo designed many civil works for his patrons and also the equipment to carry them out.

    These included:

    • A crane for excavating canals, a dredger and lock gates designed with swinging gates rather than the lifting doors of the "portcullis" or "guillotine" designs which were typically used at the time. Leonardo's gates also contained smaller hatches to control the rate of filling the lock to avoid swamping the boats.
    • Water lifting devices based on the Archimedes screw and on water wheels
    • Water wheels for powering mechanical devices and machines.
    • Architecture: Leonardo made many designs for buildings, particularly cathedrals and military structures, but none of them were ever built.
    • When Milan, with a population of 200,000 living in crowded conditions, was beset by bubonic plague Leonardo set about designing an a more healthy and pleasant ideal city. It was to be built on two levels with the upper level reserved for the householders with living quarters for servants and facilities for deliveries on the lower level. The lower level would also be served by covered carriageways and canals for drainage and to carry away sewage while the residents of the upper layer would live in more tranquil, airy conditions above all this with pedestrian walkways and gardens connecting their buildings.
    • Leonardo produced a precision map of Imola, accurate to a few feet (about 1 m) based on measurements made with two variants of an odometer or what we would call today a surveyor's wheel which he designed and which he called a cyclometer. They were wheelbarrow-like carts with geared mechanisms on the axles to count the revolutions of the wheels from which the distance could be determined. He followed up with physical maps of other regions in Italy.
  • Tools and Instruments
  • The following are examples of some of the tools and scientific instruments designed by da Vinci which were found in his notes.

    • Solar Heating - In 1515 when he worked at the Vatican, Leonardo designed a system of harnessing solar energy using a large concave mirror, constructed from several smaller mirrors soldered together, to focus the Sun's rays to heat water.
    • Improvements to the printing press to simplify its operation so that it could be operated by a single worker.
    • Anemometer - It consisted of a horizontal bar from which was suspended a rectangular piece of wood by means of a hinge. The horizontal bar was mounted on two curved supports on which a scale to measure the rotation of the suspended wood was marked. When the wind blew, the wood swung on its hinge within the frame and the extent of the rotation was noted on the scale which gave an indication of the force of the wind.
    • A 13 digit decimal counting machine - Based on a gear train and often incorrectly identified as a mechanical calculator.
    • Clock - Leonardo was one of the early users of springs rather than weights to drive the clock and to incorporate the fusée mechanism, a cone-shaped pulley with a helical groove around it which compensated for the diminishing force from the spring as it unwound. His design had two separate mechanisms, one for minutes and one for hours as well as an indication of phases of the moon.
    • He also designed numerous machines to facilitate manufacturing including a water powered mechanical saw, horizontal and vertical drilling machines, spring making machines, machines for grinding convex lenses, machines for grinding concave mirrors, file cutting machines, textile finishing machines, a device for making sequins, rope making machines, lifting hoists, gears, cranks and ball bearings.
    • Though drawings and models exist, the claim that Leonardo invented the bicycle is thought by many to be a hoax. The rigid frame had no steering mechanism and it is impossible to ride.
  • Theatrical Designs
    • Leonardo was often in demand for designing theatrical sets and decorations for carnivals and court weddings.
    • He also built automata in the form of robots or animated beasts whose lifelike movements were created by a series of springs, wires, cables and pulleys.
    • His self propelled cart, powered by a spring, was used to amaze theatre audiences.
    • He designed musical instruments including a lyre, a mechanical drum, and a viola organista with a keyboard. This latter instrument consisted of a series of strings each tuned to a different pitch. A bow in the form of a continuously rotating loop perpendicular to the strings was stretched between two pulleys mounted in front of the strings. The keys on the keyboard were each associated with a particular string and when a key was pressed a mechanism pushed the bow against the corresponding string to play the note.
  • Anatomy
  • As part of his training in Veroccio's studio, like any artist, Leonardo studied anatomy as an aid to figure drawing, however starting around 1487 and later with the doctor Marcantonio della Torre he made much more in depth studies of the body, its organs and how they function.

    • During his studies Leonardo had access to 30 corpses which he dissected, removing their skin, unravelling intestines and making over 200 accurate drawings their organs and body parts.
    • He made similar studies of other animals, dissecting cows, birds, monkeys, bears, and frogs, and comparing their anatomical structure with that of humans.
    • He also observed and tried to comprehend the workings of the cardiovascular, respiratory, digestive, reproductive and nervous systems and the brain without much success. He did however witness the killing of a pig during a visit to an abattoir. He noticed that when a skewer was thrust into its heart, that the beat of the heart coincided with the movement of blood into the main arteries. He understood the mechanism of the heart if not the function, predating by over 100 years, the conclusions of Harvey about its function.

    Because the bulk of his work was not published for over 200 years, his observations could possibly have prompted an earlier advance in medical science had they been made available during his lifetime. At least his drawings provided a useful resource for future students of anatomy.

  • Scientific Writings
  • Leonardo had an insatiable curiosity about both nature and science and made extensive observations which were recorded in his notebooks.

    They included:

    • Anatomy, biology, botany, hydraulics, mechanics, ballistics, optics, acoustics, geology, fossils

    He did not however develop any new scientific theories or laws. Instead he used the knowledge gained from his observations to improve his skills as an artist and to invent a constant stream of useful machines and devices.

"Leonardo the Inventor"

Leonardo unquestionably had one of the greatest inventive minds of all time, but very few of his designs were ever constructed at the time. The reason normally given is that the technology didn't exist during his lifetime. With his skilled draughtsmanship, Leonardo's designs looked great on paper but in reality many of them would not actually work in practice, an essential criterion for any successful invention, and this has since been borne out by subsequent attempts to construct the devices as described in his plans. This should not however detract in any way from Leonardo's reputation as an inventor. His innovations were way ahead of their time, unique, wide ranging and based on sound engineering principles. What was missing was the science.

At least he had the benefits of Archimedes' knowledge of levers, pulleys and gears, all of which he used extensively, but that was the limit of available science.

Newton's Laws of Motion were not published until two centuries after Leonardo was working on his designs. The science of strength of materials was also unheard of until Newton's time when Hooke made some initial observations about stress and strain and there was certainly no data available to Leonardo about the engineering properties of materials such as tensile, compressive, bending and impact strength or air pressure and the densities of the air and other materials. Torricelli's studies on air pressure came about fifty years before Newton, and Bernoulli's theory of fluid flow, which describe the science behind aerodynamic lift, did not come till fifty 50 years after Newton. But, even if the science had existed, Leonardo lacked the mathematical skills to make the best of it.

So it's not surprising that Leonardo had to make a lot of assumptions. This did not so much affect the function of his mechanisms nor the operating principle on which they were based, rather it affected the scale and proportions of the components and the force or power needed to operate them. His armoured tank would have been immensely heavy and difficult to manoeuvre, and it's naval version would have sunk unless its buoyancy was improved. The wooden gears used would probably have been unable to transmit the enormous forces required to move these heavy vehicles. The repeated recoil forces on his multiple-barrelled guns may have shattered their mounts, and his flying machines were very flimsy with inadequate area of the wings as well as the level of human power needed to keep them aloft. So there was nothing fundamentally wrong with most of his designs and most of the shortcomings could have been overcome with iterative development and testing programmes to refine the designs. Unfortunately Leonardo never had that opportunity.

"Leonardo the Myths"

Leonardo was indeed a genius but his reputation has also been enhanced or distorted by uncritical praise. Speculation, rather than firm evidence, about the performance of some of the mechanisms mentioned in his notebooks and what may have been in the notebooks which have been lost, has incorrectly credited him with the invention of the telescope, mathematical calculating machines and the odometer to name just three examples.

Though he did experiment with optics and made drawings of lenses, he never mentioned in his notes, a telescope, or what he may have seen with it, so it is highly unlikely that he invented the telescope.

As for his so called calculating machine: It looked very similar to the calculator made by Pascal 150 years later but it was in fact just a counting machine since it did not have an accumulator to facilitate calculations by holding two numbers at a time in the machine as in Pascal's calculator.

Leonardo's "telescope" and "calculating machine" are examples of uninformed speculation from tantalising sketches made, without corresponding explanations, in his notes. Such speculation is based on the reasoning that, if one of his sketches or drawings "looks like" some more recent device or mechanism, then it "must be" or actually "is" an early example of such a device. Leonardo already had a well deserved reputation as a genius without this unnecessary gold plating.

Similarly regarding the odometer: The claim by some, though not by Leonardo himself, that he invented the odometer implies that he was the first to envisage the concept of an odometer. The odometer was in fact invented by Vitruvius 15 centuries earlier. Leonardo invented "an" odometer, not "the" odometer. Many inventions are simply improvements, alternatives or variations, of what went before. Without a knowledge of precedents, it is a mistake to extrapolate a specific case to a general conclusion. Leonardo's design was based on measuring the rotation of gear wheels, whereas Vitruvius' design was based on counting tokens. (Note that Vitruvius also mentions in his "Ten Books on Architecture", designs for trebuchets, water wheels and battering rams protected by mobile siege sheds or armoured vehicles which were called "tortoises".)

It is rare to find an invention which depends completely on a unique new concept and many perfectly good inventions are improvements or alternatives to prior art. This applies to some of Leonardo's inventions just as it does to the majority of inventions today. Nobody would (or should) claim that Leonardo invented the clock when his innovation was to incorporate a new mechanical movement into his own version of a clock, nor should they denigrate his actual invention.

It's a great pity that Leonardo kept his works secret and that they remained unseen for so many years after his death. How might technology have advanced if he had been willing to share his ideas, to explain them to his contemporaries and to benefit from their comments?

1492 Discovery of the New World by Christopher Columbus showed that the Earth still held vast unknowns indirectly giving impetus to the scientific revolution.

1499 The first patent for an invention was granted by King Henry VI to Flemish-born John of Utynam for a method of making stained glass, required for the windows of Eton College giving John a 20-year monopoly. The Crown thus started making specific grants of privilege to favoured manufacturers and traders, signified by Letters Patent, open letters marked with the King's Great Seal.

The system was open to corruption and in 1623 the Statute of Monopolies was enacted to curb these abuses. It was a fundamental change to patent law which took away the rights of the Crown to create trading monopolies and guaranteed the inventor the legal right of patents instead of depending on the royal prerogative. So called patent law, or more generally intellectual property law, has undergone many changes since then to encompass new concepts such as copyrights and trademarks and is still evolving as and new technologies such as software and genetics demand new rules.

1500 to 1700 The Scientific Revolution and The Age of Reason

Up to the end of the sixteenth century there had been little change in the accepted scientific wisdom inherited from the Greeks and Romans. Indeed it had even been reinforced in the thirteenth century by St. Thomas Aquinas who proclaimed the unity of Aristotelian philosophy with the teachings of the church. The credibility of new scientific ideas was judged against the ancient authority of Aristotle, Galen, Ptolemy and others whose science was based on rational thought which was considered to be superior to experimentation and empirical methods. Challenging these conventional ideas was considered to be a challenge to the church and scientific progress was hampered accordingly.

In medieval times, the great mass of the population had no access to formal education let alone scientific knowledge. Their view of science could be summed up in the words of Arthur C. Clarke, "Any sufficiently advanced technology is indistinguishable from magic".

Things began to change after 1500 when a few pioneering scientists discovered, and were able to prove, flaws in this ancient wisdom. Once this happened others began to question accepted scientific theories and devised experiments to validate their ideas. In the past, such challenges had been hampered by the lack of accurate measuring instruments which had limited the range of experiments that could be undertaken and it was only in the seventeenth century that instruments such as microscopes, telescopes, clocks with minute hands, accurate weighing equipment, thermometers and manometers started to become available. Experimenters were then able to develop new and more accurate measurement tools to run their experiments and to explore new scientific territories thus accelerating the growth of new scientific knowledge.

The printing press was the great catalyst in this process. Scientists could publish their work, thus reaching a much greater audience, but just as important, it gave others working in the field, access to the latest developments. It gave them the inspiration to explore these new scientific domains from a new perspective without having to go over ground already covered by others.

The increasing use of gunpowder also had its effect. Cannons and hand held weapons swept the aristocratic knight from the field of battle. Military advantage and power went to those with the most effective weapons and heads of state began to sponsor experimentation in order to gain that advantage.

Scientific method thus replaced rational thought as a basis for developing new scientific theories and over the next 200 years scientific theories and scientific institutions were transformed, laying the foundations on which the later Industrial Revolution depended.

Some pioneers are shown below.

  • (600 B.C.) Thales The original thinker, deprecated by Aristotle.
  • (300 B.C.) Euclid promoted the disciplines of proof, logic and deductive reasoning in mathematics.
  • (269 B.C.) Archimedes followed Euclid's disciplines and was the first to base engineering inventions on mathematical principles.
  • (1450) Johannes Gutenberg did not make any scientific breakthroughs but his printing press was one of the most important developments and essential prerequisites which made the scientific revolution possible. For the first time it became easy to record information and to disseminate knowledge making learning and scholarship available to the masses.
  • (1492) Christopher Columbus' discovery of the New World showed that the World still held vast unknowns sparking curiosity.
  • (1514) Nicolaus Copernicus challenged the accepted wisdom of Ptolemy which had reigned supreme for 1400 years, that the Earth was the centre of the Universe, and proposed instead that the Universe was centred on the Sun.
  • (1543) Andreas Vesalius showed that conventional theories about human anatomy, unquestioned since they were developed over 1300 years earlier by Galen, were incorrect.
  • (1576) Tycho Brahe made detailed astronomical measurements to enable predictions of planetary motion to be based on observations rather than logical deduction.
  • (1600) William Gilbert an early advocate of scientific method rather than rational thought.
  • (1605) Francis Bacon like Gilbert, a proponent of scientific method.
  • (1608) Hans Lippershey invented the telescope, thus providing the tools for much more accurate observations, and deeper understanding of the cosmos.
  • (1609) Johannes Kepler developed mathematical relationships, based on Brahe's measurements which enabled planetary movements to be predicted.
  • (1610) Galileo Galilei demonstrated that the Earth was not the centre of the Universe and in so doing, brought himself into serious conflict with the church.
  • (1628) William Harvey outlined the true function of the heart correcting misconceptions about the functions and flow of blood as well as classical myths about its purpose.
  • (1642) Pascal together with Fermat described chance and probability in mathematical terms, rather than fate or the will of the Gods.
  • (1643) Evangelista Torricelli's invention of the barometer led to an understanding of the properties of air.
  • (1644) René Descartes challenged Aristotle's logic based on rational thinking with his own mathematical logic and attempted to describe the whole universe in mathematical terms. He was still not convinced of the value of experimental method.
  • (1656) Christiaan Huygens invented the pendulum clock enabling scientific experiments to be supported by accurate time measurements for the first time.
  • (1660) The Royal Society was founded in London to encourage scientific discovery and experiment.
  • (1661) Robert Boyle introduced the concept of chemical elements based on empirical observations rather than Aristotle's logical earth, fire, water and air.
  • (1663) Otto von Guericke devised an experiment using his Magdeburg Spheres to disprove Aristotle's claim that a vacuum can not exist.
  • (1665) Robert Hooke invented the microscope which opened a window on the previously unseen microscopic world raising questions about life itself.
  • (1666) The French Académie des Sciences was founded in Paris.
  • (1668) Antonie van Leeuwenhoek expanded on Hooke's observations and established microbiology.
  • (1687) Isaac Newton derived a set of mathematical laws which provided the basis of a comprehensive understanding of the physical world.
  • (1700) The German Academy of Sciences was founded in Berlin.

The Age of Reason marked the triumph of evidence over dogma. Or did it? There remained one great mystery yet to be unravelled but it was another 200 years before it came up for serious consideration: The Origin of Species.

1514 Polish polymath and Catholic cleric, Nicolaus Copernicus mathematician, economist, physician, linguist, jurist, and accomplished statesman with astronomy as a hobby published and circulated to a small circle of friends, a preliminary draft manuscript in which he described his revolutionary idea of the heliocentric universe in which celestial bodies moved in circular motions around the Sun, challenging the notion of the geocentric universe. Such heresies were unthinkable at the time. They not only contradicted conventional wisdom that the World was the centre of the universe but worse still they undermined the story of creation, one of the fundamental beliefs of the Christian religion. Dangerous stuff!

It was not until around 1532 that Copernicus completed the work which he called De Revolutionibus Orbium Coelestium "On the Revolutions of the Heavenly Spheres" but he still declined to publish it. Historians do not agree on whether this was because Copernicus was unsure that his observations and his calculations would be sufficiently robust enough to challenge Ptolemy's Almagest which had survived almost 1400 years of scrutiny or whether he feared the wrath of the church. Copernicus' model however was simpler than Ptolemy's geocentric model and matched more closely the observed motions of the planets. He eventually agreed to publish the work at the end of his life and the first printed copy was reportedly delivered to him on his deathbed, at the age of seventy, in 1543.

As it turned out, "De Revolutionibus Orbium Coelestium" was put on the Catholic church's index of prohibited books in 1616, as a result of Galileo's support for its revolutionary theory, and remained there until 1835.

One of the most important books ever written, De Revolutionibus' ideas ignited the Scientific Revolution (See above), but only about 300 or 400 were printed and it became known (recently) as "the book that nobody read".

1533 Frisian (now Netherlands) mathematician and cartographer Gemma Frisius proposed the idea of triangulation for surveying and producing maps. Because it was often inconvenient or difficult to measure large distances directly, he described how the distance to a distant target location could be determined locally, without actually going there, by using only angle measurements. By forming triangles to the target from reference points on a local baseline, and measuring the angles between the baseline and the lines between the reference points and the target at the vertex of the triangle, the distance to the target could be calculated using simple trigonometry. It was thus easier to survey the countryside and construct maps by dividing the area into triangles rather than squares. This method was first used in 600 B.C. by Greek philosopher Thales but was not yet commonly adopted. Triangulation is still used today in applications from surveying to celestial navigation.

In 1553 Frisius was also the first to describe how longitude could be determined by comparing local solar time with the time at some reference location provided by an accurate clock but no such clocks were available at the time.

1543 Belgian physician and professor at the University of Padua, Andries van Wesel, more commonly known as Vesalius published De Humani Corporis Fabrica (On the Structure of the Human Body), one of the most influential books on human anatomy. He carried out his research on the corpses of executed criminals and discovered that the research and conclusions published by the previous, undisputed authority on this subject, Galen, could not possibly have been based on an actual human body. Versalius was one of the first to rely on direct observations and scientific method rather than rational logic as practiced by the ancient philosophers and in so doing overturned 1300 years of conventional wisdom. Such challenges to long held theories marked the start of the Scientific Revolution.

1551 Damascus born Muslim polymath, Taqi al-Din, working in Egypt, described an impulse turbine used to drive a rotating spit over a fire. It was simply a jet of steam impinging on the blades of a paddle wheel mounted on the end of the spit. Like Hero's reaction turbine it was not developed at the time for use in more useful applications.

See more about Impulse Turbines.

See more about Steam Engines


1576 Danish astronomer and alchemist, Tycho Brahe, built an observatory where, with his assistant Johannes Kepler, he gathered data with the aim of constructing a set of tables for calculating the position of the planets for any date in the past or in the future. He lived before the invention of the telescope and his measurements were made with a cross staff, a simple mechanical device similar to a protractor used for measuring angles. Nevertheless, despite his primitive instruments, he set new standards for precise and objective measurements but he still relied on empirical observations rather than mathematics for his predictions.

Brahe accepted Copernicus' heliocentric model for the orbits of planets which explained the apparent anomalies in their orbits exhibited by Ptolemy's geocentric model, however he still clung on to the Ptolemaic model for the orbits of the Sun and Moon revolving around the Earth as this fitted nicely with the notion of Heaven and Earth and did not cause any conflicts with religious beliefs.

However, using the data gathered together with Brahe, Kepler was able to confirm the heliocentric model for the orbits of planets, including the Earth, and to derive mathematical laws for their movements.

See also the Scientific Revolution

A wealthy, hot-headed and extroverted nobleman, said to own one percent of the entire wealth of Denmark, Brahe had a lust for life and food. He wore a gold prosthesis in place of his nose which it was claimed had been cut off by his cousin in a duel over who was the better mathematician.

In 1601, Brahe died in great pain in mysterious circumstances, eleven days after becoming ill during a banquet. Until recently the accepted explanation of the cause of death, provided by Kepler, was that it was an infection arising from a strained bladder, or from rupture of the bladder, resulting from staying too long at the dining table.

By examining Brahe's remains in 1993, Danish toxicologist Bent Kaempe determined that Brahe had died from acute Mercury poisoning which would have exhibited similar symptoms. Among the many suspects, in 2004 the finger was firmly pointed by writers Joshua and Anne-Lee Gilder, at Kepler, the frail, introverted son of a poor German family.

Kepler had the motive, he was consumed by jealousy of Brahe and he wanted his data which could make him famous but it had been denied to him. He also had the means and the opportunity. After Tycho's death when his family were distracted by grief, Kepler simply walked away with the priceless observations which belonged to Tycho's heirs.

With only a few tantalising facts to go on, historians attempt to construct a more complete picture of what happened in the distant past. In Brahe's case there could be another explanation of his demise. From the available facts it could be concluded the Brahe's death was due to an accidental overdose of Mercury, which at the time was the conventional medication prescribed for the treatment for syphilis, or from syphilis itself. This is corroborated by the fact that one of the symptoms of the advanced state of the disease is the loss of the nose due to the collapse of the bridge tissue. Brahe's hedonistic lifestyle could well have made this a possibility. Kepler's actions in purloining of Brahe's data could have been a simple act of opportunism rather than the motivation for murder.

1593 The thermometer invented by Italian astronomer and physicist Galileo Galilei. It has been variously called an air thermometer or a water thermometer but it was called a thermoscope at the time. His "thermometer" consisted of a glass bulb at the end of a long glass tube held vertically with the open end immersed in a vessel of water. As the temperature changed the water would rise or fall in the tube due to the contraction or expansion of the air. It was sensitive to air pressure and could only be used to indicate temperature changes since it had no scale. In 1612 Italian Santorio Santorio added a scale to the apparatus creating the first true thermometer and for the first time, temperatures could be quantified.

There is no evidence that the decorative, so called, Galileo thermometers based on the Archimedes principle were invented by Galileo or that he ever saw one. They are comprised of several sealed glass floats in a sealed liquid filled glass cylinder. The density of the liquid varies with the temperature and the floats are designed with different densities so as to float or sink at different temperatures. There were however thriving glass blowing and thermometer crafts based in Florence (Tuscany) where the Academia del Cimento, which was noted for its instrument making, produced many of these thermometers also known as Florentine thermometers or Infingardi (Lazy-Ones) or Termometros Lentos (Slow) because of the slowness of the motion of the small floating spheres in the alcohol of the vial. It is quite likely that these designs were the work of the Grand Duke of Tuscany Ferdinand II who had a special interest in thermometers and meteorology.

1595 Swiss clockmaker Jost Burgi invented the gravity remontoire - constant force escapement which improved the accuracy of timekeeping mechanisms by over an order of magnitude.

See more about the remontoire

1600 William Gilbert of Colchester, physician to Queen Elizabeth I of England published "De Magnete" (On the Magnet) the first ever work of experimental physics. In it he distinguished for the first time static electric forces from magnetic forces. He discovered that the Earth is a giant magnet just like one of the stones of Peregrinus, explaining how compasses work. He is credited with coining the word "electric" which comes from the Greek word "elektron" meaning amber.

Many wondrous powers have been ascribed to magnets and to this day magnetic bracelets are believed by some to have therapeutic benefits. In Gilbert's time it was believed that an adulteress could be identified by placing a magnet under her pillow. This would cause her to scream or be thrown out of bed as she slept.

Gilbert proved amongst other things that the smell of garlic did not affect a ship's compass. It is not known whether he experimented with adulteresses in his bed.

Gilbert was the English champion of the experimental method of scientific discovery considered inferior to rational thought by the Greek philosopher Aristotle and his followers. He held the Copernican or heliocentric view, dangerous at the time, that the Sun, not the Earth was not the centre of the universe. He was a contemporary of the Italian astronomer Galileo Galilei (1564-1642) who made a principled stand in defence of the founding of physics on scientific method and precise measurements rather than on metaphysical principles and formal logic. These views brought Galileo into serious confrontation with the church and he was tried and punished for his heresies.

Experimental method rather than rational thought was the principle behind the Scientific Revolution which separated Science (theories which can be proved) from Philosophy (theories which can not be proved).

See also Bertrand Russell's definition of philosophy.

Gilbert died of Bubonic plague in 1603 leaving his books, globes, instruments and minerals to the College of Physicians but they were destroyed in 1666 in the great fire of London which mercifully also brought the plague to an end.

1601 An early method of hardening wrought iron to make hard edged tool steel and swords, known as the cementation process, was first patented by Johann Nussbaum of Magdeburg in Germany though the process was already known in Prague in 1574. It was also patented once more in England by William Ellyot and Mathias Meysey in 1614.

The method employed a solid diffusion process involving the diffusion of carbon into the wrought iron to increase its carbon content to between 0.5% and 1.5%. Wrought iron rods or bars were covered with powdered charcoal (called cement) and sealed in a long airtight stone or clay lined brick box, like a sarcophagus, and heated to 1,000°C in a furnace for between one and two weeks. The nature of the difusion process, resulted in a non-uniform carbon content which was high near the surface of the bar, diminishing towards its centre and the bars could still contain slag inclusions from the original precursor bloom from which the wrought iron was made. The process also caused blistering of the steel, hence the product made this way was called blister steel.

See more about Iron and Steel Making

1603 Italian shoemaker and part-time alchemist from Bologna, Vincenzo Cascariolo, searching for the "Philosopher's Stone" for turning common metals into Gold discovered phosphorescence instead. He heated a mixture of powdered coal and heavy spar (Barium sulphate) and spread it over an iron bar. It did not turn into Gold when it cooled, as expected, but he was astonished to see it glow in the dark. Though the glow faded it could be "reanimated" by exposing it to the sun and so became known as "lapis solaris" or "sun stone", a primitive method of solar energy storage in chemical form.

1605 A five digit encryption code consisting only of the letters "a" and "b" giving 32 combinations to represent the letters of the alphabet was devised by English philosopher and lawyer Francis Bacon. He called it a biliteral code. It is directly equivalent to the five bit binary Baudot code of ones and zeros used for over 100 years for transmitting data in twentieth century telegraphic communications.

More importantly Bacon, together with Gilbert, was an early champion of scientific method although it is not known whether they ever met.

Bacon criticized the notion that scientific advances should be made through rational deduction. He advocated the discovery of new knowledge through scientific experimentation. Phenomena would be observed and hypotheses made based on the observations. Tests would then be conducted to verify the hypotheses. If the tests produced reproducible results then conclusions could be made.

In his 1605 publication "The Advancement of Learning", Bacon coined the dictum "If a man will begin with certainties, he will end up with doubts; but if he will be content to begin with doubts, he shall end up in certainties".

See also the Scientific Revolution

Bacon died as a result of one of his experiments. He investigated preserving meat by stuffing a chicken with snow. The experiment was a success but Bacon died of bronchitis contracted either from the cold chicken or from the damp bed, reserved for VIP's and unused for a year, where he was sent to recover from his chill.

There are many "Baconians" who claim today that at least some of Shakespeare's plays were actually written by Bacon. One of the many arguments put forward is that only Bacon possessed the necessary wide range of knowledge and erudition displayed in Shakespeare's plays.

1608 German born spectacle lens maker Hans Lippershey working in Holland, applied for a patent for the telescope for which he envisioned military applications. The patent was not granted on the basis that "too many people already have knowledge of this invention". Nevertheless, Lippershey's patent application was the first documented evidence of such a device. Legend has it that the telescope was discovered by accident when Lippershey, or two children playing with lenses in his shop, noticed that the image of a distant church tower became much clearer when viewed through two lenses, one in front of the other. The discovery revolutionised astronomy. Up to that date the pioneering work of Copernicus, Brahe and Kepler had all been based on many thousands of painstaking observations made with the naked eye without the advantage of a telescope.

See also the Scientific Revolution

1609 On the death of Danish Imperial Mathematician Tycho Brahe in 1601, German Mathematician Johannes Kepler inherited his position along with the astronomical data that Brahe had gathered over many years of pains-taking observations. From this mass of data on planetary movements, collected without the help of a telescope, Kepler derived three Laws of Planetary Motion, the first two published as "Astronomia Nova" in 1609 and the third as "Harmonices Mundi" in 1619. These laws are:

  • The Law of Orbits: All planets move in elliptical orbits, with the Sun at one focus.
  • The Law of Areas: A line that connects a planet to the Sun sweeps out equal areas in equal times. See Diagram
  • The Law of Periods: The square of the period of any planet is proportional to the cube of the semi major axis of its orbit.

Kepler's laws were the first to enable accurate predictions of future planetary orbits and at the same time they effectively disproved the Aristotelian and Ptolemaic model of geocentric planetary motion. Further evidence was provided during the same period by Galileo (See following entry).

Kepler derived these laws empirically from the years of data gathered by Brahe, a monumental task, but he was unable to explain the underlying principles involved. The answer was eventually provided by Newton.

Recently Kepler's brilliance has been tarnished by forensic studies which suggest that he murdered Brahe in order to get his hands on his observations. (See Brahe)

See also the Scientific Revolution

1610 Italian physicist and astronomer Galileo Galilei was the first to observe the heavens through a refracting telescope. Using a telescope he had built himself, based on what he had heard about Lippershey's recent invention, he observed four moons, which had not previously been visible with the naked eye, orbiting the planet Jupiter. This was revolutionary news since it was definitive proof that the Earth was not the centre of all celestial movements in the universe, overturning the geocentric or Ptolemaic model of the universe which for more than a thousand years had been the bedrock of religious and Aristotelian scientific thought. At the same time his observations of mountains on the Earth's moon contradicted Aristotelian theory, which held that heavenly bodies were perfectly smooth spheres.

Publication of these observations in his treatise Sidereus Nuncius (Starry Messenger) gave fresh impetus to the Scientific Revolution in astronomy started by the publication of Copernicus' heliocentric theory almost 100 years before, but brought Galileo into a confrontation with the church. Charged with heresy, Galileo was made to kneel before the inquisitor and confess that the heliocentric theory was false. He was found guilty and sentenced to house arrest for the rest of his life.

In 1612, having determined that Jupiter's four brightest natural satellites, Io, Europa, Ganymede and Callisto, (also known as the Galilean Moons), made regular orbits around the planet, Galileo noted that the time at which they passed a reference position in their orbits, such as the point at which they begin to eclipse the planet, would be both regular and the same for any observer in the World. This could therefore be used as the basis for a universal timer or clock which in turn could be used to determine longitude.

Galileo carried out many investigations and experiments to determine the laws governing mechanical movement. He is famously reputed to have demonstrated that all bodies fall to Earth at the same rate, regardless of their mass by dropping different sized balls from the top of the Leaning Tower of Pisa, thus disproving Aristotle's theory that the speed of falling bodies is directly proportional to their weight but there is no evidence that Galileo actually performed this experiment. However such an experiment was also performed by Simon Stevin in 1586.

In 1971, Apollo 15 astronaut David Scott repeated Galileo's experiment on the airless Moon with a feather and a hammer demonstrating that, unhampered by any atmosphere, they both fell to the ground at the same rate.

Galileo actually attempted to measure the rate at which a body falls to Earth under the influence of gravity, but he did not have an accurate method of measuring the time since the speed of the falling body was too fast and the duration too short. He therefore determined to "dilute" the effect of gravity by rolling a ball down an inclined plane to slow it down and increase the transit time. He expected to find that the distance travelled would increase by a fixed amount for each fixed increment in time. Instead he discovered that the distance travelled is proportional to the square of the time. See more about Galileo's "Laws of Motion"

In 1602 his inquisitive mind led him to make a remarkable discovery about the motion of pendulums. While sitting in a cathedral he observed the swinging of a chandelier and using his pulse to determine the period of its swing, he was greatly surprised to find that as the movement of the pendulum slowed down, its period remained the same. His curiosity piqued he followed up with a series of experiments and determined that the only factor affecting the period of the pendulum's swing was its length. It was independent of the arc of the swing,the weight of the pendulum bob and the speed of the swing. By using pendulums of different length Galileo was able to produce timing devices which were much more accurate than his pulse.

It can't have been easy, counting and keeping a running total of pendulum swings and heart rate pulses at the same time.

About 40 years later, Christiaan Huygens developed a mathematical equation defining the period of the pendulum and went on to use the pendulum in the construction of the first accurate clocks.

See more about Oscillators and Timekeeping

1614 Scottish nobleman John Napier Baron of Merchiston, published Mirifici Logarithmorum Canonis Descriptio - Description of the Marvellous Canon (Rule) of Logarithms in which he described a new method for carrying out tedious multiplication and division by simpler addition and subtraction, together with a set of tables he had calculated for the purpose. The logarithmic tables contained 241 entries which had taken him 20 years to compute.

Napier's logarithms were not the logarithms we would recognise today. Neither were they Natural logarithms with a base of "e" as is often misquoted. Natural logarithms were invented by Euler over a century later.

Napier was aware that numbers in a geometric series could be multiplied by adding their exponents (powers) for example q2 multiplied by q3 = q5, and that division could be performed by subtracting the exponents. Simple though the idea of logarithms may be, it had not been considered before because with a simple base of 2 and exponent n, where n is a whole number, the numbers represented by 2n become very large very quickly as n increases. This meant there was no obvious way of representing the intervening numbers. The idea of fractional exponents would have, (and did eventually) solve this problem but at the end of the sixteenth century, people were just getting to grips with the notion of zero and they were not comfortable with idea of fractional powers.

To design a way of representing more numbers, while still retaining whole number exponents, Napier came up with the idea of making the base number smaller. But, if the base number was very small there would be too many numbers. Using the number 1 (unity) as a base would not work either since all the powers of 1 are equal to 1. He therefore chose (1-10-7) or 0.9999999 as the base from which he constructed his tables. Napier named his exponents logarithms from the Greek logos and arithmos roughly translated as ratio-number.

Napier's publication was an instant hit with astronomers and mathematicians. Among these was Henry Briggs, mathematics professor at Gresham College, London who travelled 350 miles to Edinburgh the following year to meet the inventor of this new mathematical tool.

He stayed a month with Napier and in discussions they considered two major improvements that they both readily accepted. Briggs suggested that the tables should be constructed from a base of 10 rather than (1-10-7) and this meant adopting fractional exponents and Napier agreed that the logarithm of 1 should be 0 (zero) rather than the logarithm of 107 being 0 as it was in his original tables. Briggs' reward was to have the job of calculating the new logarithmic tables which he eventually completed and published as Arithmetica Logarithmica in 1624. His tables contained 30,000 natural numbers to 14 places.

Meanwhile in 1617 Napier published a description of a new invention in his Rabdologiae, a "collection of rods". It was a practical method of multiplication using "numbering rods" with numbers marked off on them. Known as Napier's Bones", surprisingly they did not use his method of logarithms.(See also the following item - Gunter)

Already old and frail, Napier died the same year without seeing the final results of his work.

Briggs' logarithms are still in use today, now known as common logarithms.

Napier himself considered his greatest work to be a denunciation of the Roman Catholic Church which he published in 1593 as A Plaine Discovery of the Whole Revelation of St John.

1620 Edmund Gunter professor of astronomy at Gresham College, where Briggs was professor of mathematics, made a straight logarithmic scale engraved on a wooden rod and used it to perform multiplication and division using a set of dividers or calipers to add or subtract the logarithms. The predecessor to the slide rule. (See the following item)

1621 English mathematician and clergyman, William Oughtred, friend of Briggs and Gunter from Gresham College, put two of Gunter's scales (See previous item) side by side enabling logarithms to be added directly and invented the slide rule, the essential tool of every engineer for the next 350 years until electronic calculators were invented in the 1970s.

Oughtred also produced a circular version of the slide rule.

1628 English physician Robert Harvey published "De Motu Cordis" ("On the Motion of the Heart and Blood") in which he was the first to describe the circulation of blood and how it is pumped around the body by the heart, dispelling any remaining Aristotelian beliefs that the heart was the seat of intelligence and the brain was a cooling mechanism for the blood.

See also the Scientific Revolution

1629 Italian Jesuit priest Nicolo Cabeo published Philosophia Magnetica in which electric repulsion is identified for the first time.

1636 The first reasonably accurate measurement of the speed of sound was made by French polymath Marin Mersenne who determined it to be 450 m/s (1476 ft/s). This compares with the currently accepted velocity of 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph), or a kilometre in 2.91 seconds or a mile in 4.69 seconds in dry air at 20 °C (68 °F).

(For reference, note also that the speed of light is 300,000,000 m/s compared with the speed of sound of around 343 m/s.)

Seventeenth century methods of measuring the speed of sound were usually based on observations of artillery fire and were notoriously inaccurate. Since the transit time of light over a given distance is negligible compared with the transit time of sound, by measuring the delay between seeing the powder flash from a distant cannon and hearing the explosion, the time for the sound to cover a given distance and hence the speed could be estimated. For practical measurements the distance of the artillery from the observer had to be a kilometre or more to obtain a reasonably long delay of a few seconds which could be measured by available means. Even so, the only available methods for measuring such short times were by means of a pendulum or by counting the observer's own pulse beats which were hopelessly imprecise, error prone and dependant on operator reaction times.

Furthermore, because the effects of temperature, pressure, density, wind and moisture content of the air on the speed of propagation were unknown, they were not taken into account in the measurements.

Variations on the above procedure are still used today as traditional folk methods of estimating the distance to a lightning strike by counting the seconds between the flash and its following thunderclap.

Alternative set-ups, used at the time, for calculating the speed of sound involved creating a sharp noise in front of a wall or cliff and measuring the time delay before hearing its echo. The round trip distance to the wall and back divided by the time gives the speed of sound. Echo delays in practical, controlled sites are usually very short. A distance of 100 metres to the reflecting surface (200 metres round trip) results in an echo delay of only around half a second. This leads to great difficulties in measuring the time delay with the crude equipment available.

Milestones in the Understanding of Acoustics and Sound Propagation

  • (Circa 350 B.C.) Aristotle was one of the first to speculate on the transmission of sound, writing in his in his treatise "On the Soul" that "sound is a particular movement of air".

  • 1508 Leonardo Da Vinci, using a water analogy, showed in drawings that sound travels in waves like the waves on a pond..

  • 1635 Pierre Gassendi, French priest, philosopher, scientific chronicler and experimentalist and a friend of Mersenne, is reported to have measured the speed of sound as a somewhat high 478 m/s (1568 ft/s), though this experiment was not documented in his workbooks. Using the artillery method he compared the low rumbling sound from a cannon with the higher pitched sound of a musket from the same distance and concluded that the speed of sound is independent of the pitch (frequency).
  • Gassendi was an anatomist and did not believe the wave theory of sound. He believed that sound and light are carried by particles which are not affected by the surrounding medium of air or wind through which they travel. In other words, sound was a stream of atoms emitted from the sounding body and the speed of sound is the velocity of the moving atoms, and its frequency is the number of atoms emitted per second.

  • 1636 Marin Mersenne, in contrast to his friend Gassendi, held the more rational view that sound travelled in waves like the ripples on water. Using a pendulum to measure the time between the flash of exploding gunpowder and the arrival of the sound. He determined the speed of sound to be 450 m/s (1476 ft/s). As measurement techniques improved it was revised to a more accurate 316 m/s (1036 ft/s).
  • He also established that the intensity of sound, like that of light, is inversely proportional to the distance from its source and showed the speed to be independent of pitch as well as intensity (loudness).

    The same year Marsenne also published his "Harmonie Universelle" describing the acoustic behaviour of stretched strings as used in musical instruments which provided the basis for modern musical acoustics. The relationship between frequency and the tension, weight, and the length of the strings was expressed in three laws known as Mersenne's Laws as follows:

    The fundamental frequency f0 of a vibrating string (that is without harmonics) is:

    1. Inversely proportional to the length L of the string (also known as Pythagoras Law).  f0∝1/L
    2. Inversely proportional to the square root of the mass per unit length μ.                       f0∝1√/μ
    3. Proportional to the square root of the stretching force F.                                              f0∝F

    The three laws can be combined in a single exression thus:

    f0=1/2L. √(F/μ)

    Known as the "Father of Acoustics", Mersenne regularly corresponded with the leading mathematicians, astronomers and philosophers of the day, and in 1635 set up the informal, private Académie Parisienne where140 correspondents shared their research. This was the direct precursor of the French Académie des Sciences established by Colbert in 1666

  • 1660 Giovanni Alfonso Borelli and Vincenzo Viviani working at the Accademia del Cimento in Florence improved the sound timing techniques resulting in more consistent results and a value of 350 m/s (1148 ft/s) was generally accepted as the speed of sound.

  • 1660 Robert Boyle using an improved vacuum pump, showed that the sound intensity from a bell housed in a a glass chamber diminished to zero as the air was pumped out. From this he concluded that sound can not be transmitted through a vacuum and that sound is a pressure wave which requires a medium such as air to transmit the sound. See also the luminiferous aether and the transmission of light.

  • 1687 Isaac Newton in his Principia Mathematica showed that the speed of sound depended on the density and compressibility of the medium through which it travelled and could be calculated from the following relationship using air as an example.
  • V = √(P/ρ)

    Where: V is the sound velocity, P is the atmospheric pressure and ρ is the density of the air and the ratio P/ρ is a measure of its compressability.

    Newton used echoes from a wall at the end of an outdoor corridor at Trinity College, Cambridge to estimate the speed of sound to verify his calculations but the calculated value of 295 m/s (968 f/s), was consistenly around 16% less than his measured experimental values and those achieved by others at the time.

    The unexplained difference is attributed to the assumptopns made and not made. These include the following:

    • Newton used a mechanical interpretation of sound as being "pressure" pulses transmitted through adjacent fluid particles.
    • When a pulse is propagated through a fluiid, particles of the fluid move in simple harmonic motion at a constant frequency and if it is true for one particle it must be true for all adjacent particles.
    • Possible errors due to temperature, pressure, moisture content and wind, elasticity of the air and whether they were constant, proportional or non-linear were mostly unknown at the time and were consequently ignored.

  • 1740 Giovanni Lodovico Bianconi, an Italian doctor demonstrated that the speed of sound in air increases with temperature. This is because molecules at higher temperatures have more energy and vibrate more quickly and since they vibrate faster, they can transmit sound waves more quickly.

  • 1746 Jean-Baptiste le Rond d'Alembert, a French philosopher, mathematician and music theorist deduced the Wave Equation relating the velocity of a sound wave v to its frequency f and wavelength λ, based on studies of vibrating strings, as follows:
  • v = f λ

    The relationship also applies to electromagnetic waves.


  • 1802 Pierre-Simon Laplace and his young protégé Jean-Baptiste Biot rectified Newton's troublesome error and followed up by publishing a formal correction in 1816. They explained that in a pressure wave, when the sound wave compresses and rarefies the air in quick succession, Boyles Law does not apply because the temperature does not remain constant. Heat is liberated during compression part of the cycle, but because of the relatively high frequency of the sound wave, the heat does not have time to dissipate or be reabsorbed during the low pressure half of the cycle. This causes the local temperature to increase, in turn increasing the local pressure and raising the speed of the sound correspondingly. Thus Newton's calculations were brought into line with the experimental results.
  • In modern terms, the rapidly fluctuating compression and expansion of air through which the sound wave passes is an adiabatic process, not an isothermal process).

1642 At the age of eighteen, French mathematician and physicist, Blaise Pascal constructed a mechanical calculator capable of addition and subtraction. Known as the Pascaline, it was the forerunner of computing machines. Despite its utility, this great innovation failed to capture the imagination (or the attention) of the scientific and commercial public and only fifty were made. Thirty years later it was eclipsed by Leibniz' four function calculator which could perform multiplication and division as well as addition and subtraction.

Pascal also did pioneering work on hydraulics, resulting in the statement of Pascal's principle, that "pressure will be transmitted equally throughout a confined fluid at rest, regardless of where the pressure is applied". He explained how this principle could be used to exert very high forces in a hydraulic press. Such a system would have two cylinders with pistons with different cross-sectional areas connected to a common reservoir or simply connected by a pipe. When a force is exerted on the smaller piston, it creates a pressure in the reservoir proportional to the area of the piston. This same pressure also acts on the larger piston, but because its area is greater, the pressure is translated into a larger force on the larger piston. The difference in the two forces is proportional to the difference in area of the two pistons and the hydraulic, mechanical advantage is equal to the ratio of the areas of the two pistons. Thus the cylinders act in a similar way to a lever, as described by Archimedes, which effectively magnifies the force exerted. 150 years later Bramah was granted a patent for inventing the hydraulic press.

The unit of pressure was recently named the "Pascal" in his honour, replacing the older, more descriptive, pounds per square inch (psi) or Newtons per square metre (N/M2).

Besides hydraulics, Pascal explained the concept of a vacuum. At the time, the conventional Aristotelian view was that the space must be full with some invisible matter and a vacuum was considered an impossibility.

In 1653 Pascal described a convenient shortcut for determining the coefficients of a binomial series, now called Pascal's Triangle and the following year, in response to a request from a gambling friend, he used it to derive a method of calculating the odds of particular outcomes of games of chance. In this case, two players wishing to finish a game early, wanted to divide their remaining stakes fairly depending on their chances of winning from that point. To arrive at a solution, he corresponded with fellow mathematician Fermat and together they worked out the notion of expected values and laid the foundations of the mathematical theory of probabilities.

See Pascal's Triangle and Pascal Probability

Pascal did not claim to have invented his eponymous triangle. It was known to Persian mathematicians in the eleventh and twelfth centuries and to Chinese mathematicians in the eleventh and thirteenth centuries as well as others in Europe and was often named after local mathematicians.

For most of his life Pascal suffered from poor health and he died at the age of 39 after abandoning science and devoting most of the last ten years of his short life to religious studies culminating in the publication (posthumously) of Pensées (Thoughts), a justification of the Christian faith.

See also the Scientific Revolution

1643 Evangelista Torricelli served as Galileo's secretary and succeeded him as court mathematician to Grand Duke Ferdinand II and in 1643 made the world's first barometer for measuring atmospheric or air pressure by balancing the pressure force, due to the weight of the atmosphere, against the weight of a column of mercury. This was a major step in the understanding of the properties of air.

1644 French philosopher and mathematician René Descartes published Principia Philosophiae in which he attempts to put the whole universe on a mathematical foundation reducing the study to one of mechanics. Considered to be the first of the modern school of mathematics, he believed that Aristotle's logic was an unsatisfactory means of acquiring knowledge and that only mathematics provided the truth so that all reason must be based on mathematics.

He was still not convinced of the value of experimental method considering his own mathematical logic to be superior.

His most important work La Géométrie, published in 1637, includes his application of algebra to geometry from which we now have Cartesian geometry. He was also the first to describe the concept of momentum from which the law of conservation of momentum was derived.

See also the Scientific Revolution

Descartes accepted sponsorship by Queen Christina of Sweden who persuaded him to go to Stockholm. Her daily routine started at 5.00 a.m. whereas Descartes was used to rising at at 11 o'clock. After only a few months in the cold northern climate, walking to the palace for 5 o'clock every morning, he died of pneumonia.

1646 The word Electricity coined by English physician Robert Browne even though he contributed nothing else to the science.


1651 German chemist Johann Rudolf Glauber in his "Practise on Philosophical Furnaces" describes a safety valve for use on chemical retorts. It consisted of a conical valve with a lead cap which would lift in response to excessive pressure in the retort allowing vapour to escape and the pressure to fall. The weight of the cap would reseat the valve once the pressure returned to an acceptable level. Today, modern implementations of Glauber's valve are the basis of the pressure vents incorporated into sealed batteries to prevent rupture of the cells due to pressure build up.

In 1658 Glauber published Opera Omnia Chymica "Complete Works of Chemistry", a description of different techniques for use in chemistry which was widely reprinted.

1654 The first sealed liquid-in-glass thermometer produced by the artisan Mariani at the Academia del Cimento in Florence for the Grand Duke of Tuscany, Ferdinand II. It used alcohol as the expanding liquid but was inaccurate in absolute terms, although his thermometers agreed with each other, and there was no standardised scale in use.

1656 Building on Galileo's discoveries, Dutch physicist and astronomer Christiaan Huygens determined that the period P of a pendulum is given by:

P = 2 π √(l/g)

Where l is the length of the pendulum and g is the acceleration due to gravity.

Huygens made the first practical pendulum clock making accurate time measurement possible for the first time. Previous mechanical clocks had pointers which indicated the progress of slowly rising water or slowly falling weights and were only accurate to large fractions of an hour. Huygens clock enabled time to be measured in seconds. It depended on gearing a mechanical indicator to the constant periodic motion of a pendulum. Falling weights drove the pointer mechanism and transferred just enough energy to the pendulum to overcome friction and air resistance so that it did not stop.

Huygens pendulum reduced the loss of time by clocks from about 15 minutes per day to about 15 seconds per day.

In 1675 Huygens published in the French Journal de Sçavans, his design for the balance spring escapement which replaced the clock's pendulum regulator, enabling the design of watches and portable timekeepers.

The pendulum clock however remained the world's most accurate time-keeper for nearly 300 years until the invention of the quartz clock in 1927.

See more about Huygens' Clocks

Huygens also made many astronomical observations noting the characteristics of Saturn's rings and the surface of Mars. He was also the first to make a reasoned estimate of the distance of the stars. He assumed that Sirius had the same brightness as the Sun and from a comparison of the light intensity received here on Earth he calculated the distance to Sirius to be 2.5 trillion miles. It is actually about 20 times further away than this. There was however nothing wrong with Huygens' calculations. It was the assumption which was incorrect. Sirius is actually much brighter than the Sun, but he had no way of knowing that. Had he know the true brightness of Sirius, his estimation would have been much closer to the currently accepted value.

1658 Irish Archbishop James Ussher, following a literal interpretation of the bible, calculated that the Earth was created on the evening of 22 October 4004 B.C.

1660 English mathematician and astronomer, Richard Towneley together with his friend, physician Henry Power investigated the expansion of air at different altitudes by enclosing a fixed mass of air in a Torricelli/Huygens U-tube with its open end immersed in a dish of mercury. They noted the expansion of the enclosed air at different altitudes on a hill near their home and concluded that gas pressure, the external atmospheric pressure of the air on the mercury, was inversely proportional to the volume. They communicated their findings to Robert Boyle a distinguished contemporary chemist who verified the results and published them two years later as Boyle's Law. Boyle referred to Towneley's conclusions as "Towneley's Hypothesis".

See also Towneley's improvements to the pendulum clock timekeeping mechanism. Another of his ideas for which others appear to have got the credit.

1660 The Royal Society founded in London as a "College for the Promoting of Physico-Mathematical Experimental Learning", which met weekly to discuss science and run experiments. Original members included chemist Robert Boyle and architect Christopher Wren.

See also the Scientific Revolution

1661 Huygens invents the U tube manometer, a modification of Torricelli's barometer, for determining gas pressure differences. In a typical "U Tube" manometer the difference in pressure (really a difference in force) between the ends of the tube is balanced against the weight of a column of liquid. The gauges are only suitable for measuring low pressures, most gauges recording the difference between the fluid pressure and the local atmospheric pressure when one end of the tube is open to the atmosphere.

1661 Irish chemist Robert Boyle published "The Sceptical Chymist" in which he introduced the concept of elements. At the time only 12 elements had been identified. These included nine metals, Gold, Silver, Copper, Tin, Lead, Zinc, Iron, Antimony and Mercury and two non metals Carbon and Sulphur all of which had been known since antiquity as well as Bismuth which had been discovered in Germany around 1400 A. D.. Platinum had been known to South American Indians from ancient times but only became to the attention of Europeans in the eighteenth century. Boyle himself discovered phosphorus which he extracted from urine in 1680 taking the total of known elements to fourteen.

Though an alchemist himself, believing in the possibility of transmutation of metals, he was one of the first to break with the alchemist's tradition of secrecy and published the details of his experimental work including failed experiments.

See also the Scientific Revolution

1662 Boyle published Boyle's Law stating that the pressure and volume of a gas are inversely proportional.


The first of the Gas Laws.

The relationship was originally discovered in 1660 by English mathematician Richard Towneley but attributed to Boyle. Both Towneley and Boyle were not aware that the relationship was temperature dependent and it was not until 1676 that the relationship was rediscovered by French physicist and priest, Abbé Edme Mariotte, and shown to apply only when the gas temperature is held constant. The law is known as Mariotte's Law in non-English speaking countries.

See also Boyle on Sound Transmission

1663 Otto von Guericke the Burgomaster of Magdeburg in Germany invented the first electric generator, which produced static electricity by rubbing a pad against a large rotating sulphur ball which was turned by a hand crank. It was essentially a mechanised version of Thales demonstrations of electrostatics using amber in 600 B.C. and the first machine to produce an electric spark. Von Guericke had no idea what the sparks were and their production by the machine was regarded at the time as magic or a clever trick. The device enabled experiments with electricity to be carried out but since it was not until 1729 that the possibility of electric conduction was discovered by Gray, the charged sulphur ball had to be moved to the place where the electric experiment took place. Von Guericke's generator remained the standard way of producing electricity for over a century.

Von Guericke was famed more for his studies of the properties of a vacuum and for his design of the Magdeburg Hemispheres experiment. In 1650, in a challenge to Aristotle's theory that a vacuum can not exist, like many of Aristotle's theories, accepted uncritically by philosophers as conventional wisdom for centuries and encapsulated in the saying "Nature abhors a vacuum", von Guericke set about disproving this theory by experimental means. In 1650 he designed a piston based air pump with which he could evacuate the air from a chamber and he used it to create a vacuum in experiments which showed that sound of a bell in a vacuum can not be heard, nor can a vacuum support a candle flame or animal life. To demonstrate the strength of a vacuum, in 1654 he constructed two hollow copper hemispheres which fitted together along a greased flange forming a hollow sphere. When the air was evacuated from the sphere, the external air pressure held the hemispheres together and two teams of horses could not pull them apart, yet when air was released into the sphere the hemispheres simply fell apart.

(See Magdeburg Hemispheres picture).

See also the Scientific Revolution

1665 Boyle published a description of a hydrometer for measuring the density of liquids which was essentially the same as those still in use today for measuring the specific gravity (S.G.) of the electrolyte in Lead Acid batteries. Hydrometers consist of a sealed capsule of lead or mercury inside a glass tube into which the liquid being measured is placed. The height at which the capsule floats represents the density of the liquid.

The hydrometer is however considered to be the invention of Greek mathematician Hypatia.

1665 The Journal des Sçavans (later renamed Journal des Savants), the earliest academic journal to be published in Europe was established. Its content included obituaries of famous men, church history, and legal reports. It was followed two months later by the first appearance of the Philosophical Transactions of the Royal Society.

1665 English polymath, Robert Hooke published Micrographia in which he illustrated a series of very small insects and plant specimens he had observed through a microscope he had constructed himself for the purpose. It included a description of the eye of a fly and tiny sections of plant materials for which he coined the term "cells" because their distinctive walls reminded him of monk's or prison quarters. The publication also included the first description of an optical microscope, and it is claimed, was the inspiration to Antonie van Leeuwenhoek who is often credited himself with the invention of the microscope. Hooke's publication was the first major publication of the recently founded Royal Society and was the first scientific best-seller, inspiring a wide public interest in the new science of microscopy.

See also the Scientific Revolution

1666 The French Académie des Sciences was founded in Paris by King Louis XIV at the instigation of Jean-Baptiste Colbert the French Minister of Finances, as a government organisation with the aim of encouraging and protecting French scientific research. Colbert's dirigiste economic policies were protectionist in nature and involved the government in regulating French trade and industry, echoes of which remain to this day.

1668 Dutch draper, haberdasher and scientist, Antonie Phillips van Leeuwenhoek, possibly inspired by Hooke's Micrographia (see above) made his first microscope. Known as the "Father of Microbiology" he subsequently produced over 450 high quality lenses and 247 microscopes which he used to investigate biological specimens. He was the first to observe and describe single-celled organisms and was also the first to observe and record muscle fibers, bacteria, spermatozoa, and blood flow in capillaries. Van Leeuwenhoek kept the British Royal Society informed of the results of his extensive investigations and eventually became a member himself.

1668 Scottish mathematician and astronomer James Gregory published Geometriae Pars Universalis (The Universal Part of Geometry) in which he proved the fundamental theorem of calculus, that the two operations of differentiation and integration were the inverses of eachother. A system of infinitesimals, which we would now call integration had been used by Archimedes circa 260 B.C to calculate areas. Later, the concepts of rate and continuity had been studied by Oxford and other scholars since the fourteenth century. But before Gregory, nobody had connected geometry, and the calculation of areas, to motion, and the calculation of velocity.

A more general proof of the relationship between integrals and differentials was developed by English mathematician and theologian Isaac Barrow. It was published posthumously in 1683, by fellow mathematician John Collins, in the Lectiones Mathematicae which summarised Barrow's work, carried out between 1664 and 1677, on the relationships between the estimation of tangents and areas (called quadratures at the time) which mirrored the procedures used in differential and integral calculus.

In 1663 at the age of 23 Barrow was selected as the first Lucasian professor at Cambridge. In 1669 he resigned his position to study divinity for the rest of his life. The Lucasian Chair and the baton for developing the calculus were passed to his student Isaac Newton who was already developing his own ideas on its practical applications around the same time, twenty years before the publication of his Principia Mathematica.

Meanwhile Gregory was one of the first to investigate the properties of transcendental functions and their application to trigonometry and logarithms. A transcendental function "transcends" algebra in that it cannot be expressed in terms of a finite sequence of the algebraic operations of addition, multiplication, and root extraction. Transcendental numbers are not rational, algebraic numbers which can be expressed as integers or ratios of integers. They are the sum of an infinite series. Examples of transcendental functions include the exponential function, the logarithm, and the trigonometric functions. Transcendental numbers include π and the exponential e (Euler's number)

Gregory developed a method of calculating transcendental numbers by a process of successive differentiation to produce an infinite power series which converges towards the result but he was unable to prove conclusively that π and e were transcendental. The proof was confirmed many years later after his untimely death at the age of only 36.

English mathematician Brook Taylor applied Gregory's theory to various trigonometric and logarithmic functions to produce corresponding series which he published in his book Methodus incrementorum directa et inversa in 1715. These series became known as Taylor expansions. Scottish mathematician Colin Maclaurin subsequently developed a modified version or special case of the Taylor expansion, simplifying it by centring it on zero which became known as the Maclaurin expansion.

Taylor and Maclaurin expansions are used extensively today in modern computer systems to provide mathematical approximations for trigonometric, logarithmic and other transcendental functions. See examples.

1675 Boyle discovered that electric force could be transmitted through a vacuum and observed attraction and repulsion.

1676 Prolific English engineer, surveyor, architect, physicist, inventor, socialite and self publicist, Robert Hooke, considered by some to be England's Leonardo (there were others - see Cayley), is now mostly remembered for for Hooke's Law for springs which states that the extension of a spring is proportional to the force applied, or as he wrote it in Latin "Ut tensio, sic vis" ("as is the extension, so is the force"). From this the energy stored in the spring can be calculated by integrating the force times the displacement over the extension of the spring. The force per unit extension is known as the spring constant. Hooke actually discovered his law in 1660, but afraid that he would be scooped by his rival Newton, he published his preliminary ideas as an anagram "ceiiinosssttuv" in order to register his claim for priority. It was not until 1676 that he revealed the law itself. The forerunner of digital time stamping?

In 1657 Hooke was the first to propose using a spring rather than gravity to stimulate the oscillator in clock timekeeping regulators, eliminating the pendulum and enabling much smaller, portable clocks and watches. He envisaged the back and forth bending of a straight flat spring to provide the necessary force, but it was Huygens however who later made the first practical clocks based on this method.

The following year, Hooke invented the Anchor Escapement the essential timekeeping mechanism used in long case (granfather) pendulum clocks for over 200 years until it was gradually replaced by the more accurate deadbeat escapement.

See more about Hooke's clock mechanisms.

Hooke was surveyor of the City of London and assistant to Christopher Wren in rebuilding the city after the great fire of 1666. He made valuable contributions to optics, microscopy, astronomy, the design of clocks, the theories of springs and gases, the classification of fossils, meteorology, navigation, music, mechanical theory and inventions, but despite his many achievements he was overshadowed by his contemporary Newton with whom he was unfortunately, constantly in dispute. Hooke claimed a role in some of Newton's discoveries but he was never able to back up his theories with mathematical proofs. Apparently there was at least one subject which he had not mastered.

1673 Between the years 1673 and 1686, German mathematician, diplomat and philosopher, Gottfried Wilhelm Leibniz, developed his theories of mathematical calculus publishing the first account of differential calculus in 1684 followed by the explanation of integral calculus in 1686. Unknown to him these techniques were also being developed independently by Newton. Newton got there first but Leibniz published first and arguments about priority raged for many years afterwards. Leibniz's notation has been adopted in preference to Newton's but the concepts are the same.

He also introduced the words function, variable, constant, parameter and coordinates to explain his techniques.

Leibniz was a polymath and another candidate for the title "The last man to know everything". As a child he learned Latin at the age of 8, Greek at 14 and in the same year he entered the University of Leipzig where he earned a Bachelors degree in philosophy at the age of 16, a Bachelors degree in law at 17 and Masters degrees in both philosophy and law at the age of 20. At 21 he obtained a Doctorate in law at Altdorf. In 1672 when he was 26, his diplomatic travels took him to Paris where he met Christiaan Huygens who introduced him to the mathematics of the pendulum and inspired him to study mathematics more seriously.

In 1679 Leibniz proposed the concept of binary arithmetic in a letter written to French mathematician and Jesuit missionary to China, Joachim Bouvet, showing that any number may be expressed by 0's and 1's only. Now the basis of digital logic and signal processing used in computers and communications.

Surprisingly Leibniz also suggested that God may be represented by unity, and "nothing" by zero, and that God created everything from nothing. He was convinced that the logic of Christianity would help to convert the Chinese to the Christian faith. He believed that he had found an historical precedent for this view in the 64 hexagrams of the Chinese I Ching or the Book of Changes attributed to China's first shaman-king Fuxi (Fu Hsi) dating from around 2800 B.C. and first written down as the now lost manual Zhou Yi in 900 B.C.. A hexagram consists of blocks of six solid or broken lines (or stalks of the Yarrow plant) forming a total of 64 possibilities. The solid lines represent the bright, positive, strong, masculine Yang with active power while the broken or divided lines represent the dark, negative, weak, feminine Yin with passive power. According to the I Ching, the two energies or polarities of the Yin and Yang are both opposing and complementary to each other and represent all things in the universe which is a progression of contradicting dualities.

Although the I Ching had more to do with fortune telling than with mathematics, there were other precedents to Leibniz's work. The first known description of a binary numeral system was made by Indian mathematician Pingala variously dated between the 5th century B.C. or the 2nd century B. C..

In 1671 Leibniz invented a 4 function mechanical calculator which could perform addition, subtraction, multiplication and division on decimal numbers which he demonstrated to the Royal Society in London in 1673 but they were not impressed by his crude prototype machine. (Pascal's 1642 calculator could only perform addition and subtraction.) It was not until 1676 that Leibniz eventually perfected it. His machine used a stepped cylinder to bring into mesh different gear wheels corresponding to the position of units, tens, hundreds etc. to operate on the particular digit as required. Strangely, as the inventor of binary arithmetic, he did not use it in his calculator.

His most famous philosophical proposition was that God created "the best of all possible worlds".

1681 French physicist and inventor Denis Papin invented the pressure release valve or safety valve to prevent explosions in pressure vessels. Although Papin is credited with the invention, safety valves had in fact been described by Glauber thirty years earlier, however Papin's valve was adjustable for different pressures by means of moving the lead weight along a lever which kept the valve shut. Papin's safety valve became a standard feature on steam engines saving many lives from explosions

The invention of the safety valve came as a result of his work with pressurised steam. In 1679 he had invented the pressure cooker which he called the steam digester.

Observing that the steam tended to lift the lid of his cooker in 1690 Papin also conceived the idea of using the pressure of steam to do useful work. He introduced a small amount of water into a cylinder closed by a piston. On heating the water to produce steam, the pressure of the steam would force the piston up. Cooling the cylinder again caused the steam to condense creating a vacuum under the piston which would pull it down (In fact the atmospheric pressure would push the piston down). This pumping action by a piston in a cylinder was the genesis of the reciprocating steam engine. Papin envisaged two applications for his piston engine. One was a toothed rack attached to the piston whose movement turned a gear wheel to produce rotary motion. The other was to use the reciprocating movements of the piston to move oars or paddles in a steam powered boat. Unfortunately he was unable to attract sponsors to enable him to develop these ideas. Papin was not the first to use a piston, von Guericke came before him, but he was the first to use it to capture the power of steam to do work.

In 1707, with the collaboration of Gottfried Leibniz (still smarting over his dispute with Isaac Newton), Papin published " The New Art of Pumping Water by Using Steam". The Papin / Leibniz pump had many similarities to Savery's 1698 water pump and their claims resulted in a protracted dispute involving the British Royal Society as to the true inventor of the steam driven water pump. Savery's pump did not use a piston but used a vacuum to draw water from below the pump and steam pressure to discharge it at a higher level. Papin's pump on the other hand used only steam pressure and could not draw water from a lower level. (See diagram of Papin's Steam Engine)

Unlike Savery's pump, Papin's pump used a closed cylinder, adjacent to (or even partially immersed in) the lower pool, fed with water from the pool through a non-return valve at the bottom of the cylinder. In the cylinder a free piston rested on the surface of the water which, at it's highest point, was level with the water in the pool. Steam from a separate boiler introduced above the piston forced it downwards displacing the water in the cylinder through another non-return valve at the bottom of the cylinder and upwards to the discharge level. Simply by exhausting the steam from the cylinder through a tap, the external water pressure would cause the cylinder to refill with water through the non-return valve at the base of the cylinder elevating the piston once more to the level of the surrounding water pool. Cooling was unnecessary since the design did not depend on creating a vacuum in the cylinder.

Papin also suggested a way of using his pump to create rotary motion. He proposed to feed the water raised by the pump over a waterwheel returning it to a lower reservoir in a closed loop system.

Like many gifted inventors Papin died destitute.

See more about Steam Engines


1687 "Philosophiae Naturalis Principia Mathematica" - Mathematical Principles of Natural Philosophy published by English physicist and mathematician Isaac Newton. One of the most important and influential books ever published, it was written in Latin and not translated into English until 1729.

By coincidence Newton was born in 1642, the year that Galileo died.

He made significant advances in the study of Optics demonstrating in 1672 that white light is made up from the spectrum of colours observed in the rainbow. He used a prism to separate white light into its constituent colour spectrum and by means of a second prism he showed that the colours could be recombined into white light.

In 1668 he designed and made the first known relecting telescope, based on a concave primary mirror and a flat secondary mirror.

He is perhaps best remembered however for his Mechanics, the Laws of Motion and Gravitation which his "Principia" contains.

Newton's Laws of Motion can be summarised as follows:

  • First Law: - Any object will remain at rest or in uniform motion in a straight line unless compelled to change by some external force.
  • Second Law: - The acceleration a of a body is directly proportional to, and in the same direction as, the net force F acting on it, and inversely proportional to its mass m. Thus, F = ma.
  • Third law: - To every action there is an equal and opposite reaction.

70 years earlier, Galileo came very close to developing these relationships but he had neither the mathematical tools nor the instruments to make precise measurements to prove his theories. Newton's first law is a restatement of Galileo's concept of inertia or resistance to change which he measured by its mass. See a Comparison of Galileo's and Newton's "Laws of Motion"

Newton also developed the Law of Universal Gravitation which states that any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Thus:

F = G m1m2 / r2


F is force between the bodies

G is the Universal Gravitational Constant

m1 and m2 are the masses of the two bodies

r is the distance between the centres of the bodies

Newton was thus able to calculate or predict gravitational forces using the concept of action at a distance. He was also able to explain that the motion of tides was due to the varying effect on the oceans caused by the Earth's daily rotation as the distance between the Moon and the oceans changed as the oceans rotated through the constant gravitational field between the Earth and the Moon.

He did not discover gravity however, nor could he explain it. Galileo was well aware of the effects of gravity, and so was Huygens, a contemporary of Newton, who believed Descartes' earlier theory that gravity could be explained in mechanical terms as a high speed vortex in the aether which caused tiny particles to be thrown outwards by the centrifugal force of the vortex while heavier particles fell inwards due to balancing centripetal forces. Huygens never accepted Newton's inverse square law of gravity.

Newton's concept that planetary motion was due to gravity was completely new. Before that, the motion of heavenly bodies had been explained by Gilbert as well as his contemporary the German astronomer Kepler (1571-1630), and others as being due to magnetic forces.

Even now in the twenty first century, will still do not have a satisfactory explanation of the nature of gravitational forces.

Newton was the giant of the Scientific Revolution. He assimilated the advances made before him in mathematics, astronomy, and physics to derive a comprehensive understanding of the physical world. The impact of the publication of Newton's laws of dynamics on the scientific community was both profound and wide ranging. The laws and Newton's methods provided the basis on which other theories, such as acoustics, fluid dynamics, kinetic energy and work done were built as well as down to earth technical knowledge which enabled the building of the machines to power the Industrial Revolution and, at the other end of the spectrum, they explained the workings of the Universe.

However, of equal or even greater importance was the fact that Newton showed for the first time, the general principle that natural phenomena, events and time varying processes, not just mechanical motions, obey laws that can be represented by mathematical equations enabling analysis and predictions to be made. The laws of nature represented by the laws of mathematics, the foundation of modern science. The 3 volume publication was thus a major turning point in the development of scientific thought, sweeping away superstition and so called "rational deduction" as ways of explaining the wonders of nature.

Newton's reasoning was supported by his invention of the mathematical techniques of Differential and Integral Calculus and Differential Equations, actually developed in 1665 and 1666, twenty years before he wrote the "Principia" but not used in the proofs it contains. These were major advances in scientific knowledge and capability which extended the range of existing mathematical tools available for characterising nature and for carrying out scientific analysis.

See also Gregory's earlier contribution to calculus theory.

Newton engaged in a prolonged feud with Robert Hooke who claimed priority on some of Newton's ideas. Newton's oft repeated quotation "If I have seen further, it is by standing on the shoulders of giants." was actually written in a sarcastic letter to Hooke, who was almost short enough to be classified as a dwarf, with the implication that Hooke didn't qualify as one of the giants.

Leibniz working contemporaneously with Newton also developed techniques of differential and integral calculus and a dispute developed with Newton as to who was the true originator. Newton's discovery was made first, but Leibniz published his work before Newton. However there is no doubt that both men came to the ideas independently. Newton developed his concept through a study of tangents to a curve and also considered variables changing with time, while Leibniz arrived at his conclusions from calculations of the areas under curves and thought of variables x and y as ranging over sequences of infinitely close values.

Newton is revered as the founder of modern physical science, but despite the great fame he achieved in his lifetime, he remained a modest, diffident, private and religious man of simple tastes. He never married, devoting his life to science.

Newton didn't always have his head in the clouds. In his spare time, when he wasn't dodging apples, he invented the cat-flap.

1698 Searching for a method of replacing the manual or animal labour for pumping out the seeping water which gathered at the bottom of coal mines, English army officer Thomas Savery designed a mechanical, or more correctly, a hydraulic water pump powered by steam. He called the process "Raising Water by Fire". Savery was impressed by the great power of atmospheric pressure working against a vacuum as demonstrated by von Guericke's Magdeburg Hemispheres experiment. He realised that a vacuum could be produced by condensing steam in a sealed chamber and he used this principle as the basis for the first practical steam driven water pump which became known as "The Miner's Friend". Savery's pump did not produce any mechanical motion but used atmospheric pressure to force the water up a vertical pipe from a well or pond below, to fill the vacuum in the steam chamber above, and steam pressure to drive the water in the steam chamber up a vertical discharge pipe to a level above the steam chamber.

(See diagram of Savery's Steam Engine)

The essential components of the pump were a boiler producing steam, a steam chamber at the heart of the system and suction and discharge water pipes each containing a non-return flap valve he called a clack.

Starting with some water in the steam chamber, the steam valve from the boiler is opened introducing steam into the steam chamber where the pressure of the steam forces the water out through a non-return flap valve into the discharge pipe. The head of water in the discharge pipe keeps the flap valve closed so the water can not return into the steam chamber. The steam supply to the chamber is then turned off and the chamber is cooled from the outside with cold water which causes the steam in the chamber to condense creating a vacuum in the chamber. The vacuum in turn causes water to be sucked up from the well or lower pond through another flap valve in the induction pipe into the steam chamber. The head of water in the steam chamber keeps the flap valve closed so that the water can not flow back to the well. Once the chamber is full, steam is fed once more into the chamber and the cycle starts again.

Efficiency was improved by using two parallel steam chambers alternately such that one of the chambers was charged with steam while the other chamber was cooled. The theoretical maximum depth from which Savery's engine can draw water is limited by the atmospheric pressure which can support a head of 32 feet (10 M) but because of leaks the practical limit is about 25 feet. In a mine this would require the engine to be below ground close to the water level, but as we know, fire and coal mines don't mix. On the discharge side the maximum height to which the water can be raised is limited by the available steam pressure and also by the safety of the pressure vessels whose solder joints are particularly vulnerable, a serious drawback with the available 17th century technology.

See more about Steam Engines


1700 At the instigation of Leibniz, King Frederick I of Prussia founded the German Academy of Sciences in Berlin to rival Britain's Royal Society and the French Académie des Sciences. Leibniz was appointed as its first president

1701 English gentleman farmer Jethro Tull, developed the seed drill, a horse-drawn sowing device which mechanised the planting of seeds, precisely positioning them in the soil and then covering them over. It thus enabled better control of the distribution and positioning of the seeds leading to improvements of up to nine times in crop yields per acre (or hectare). For the farm hand, the seed drill cut out some of the back-breaking work previously employed in the task but the downside was that it also reduced the number of farm workers needed to plant the crop. The seed drill was a relatively simple device which could be made by local carpenters and blacksmiths. Its combined benefits of higher crop yields and productivity improvements were the first steps in mechanised farming which revolutionised British agriculture.

The design concept was not new since similar devices had been used in Europe in the middle ages. Single tube seed drills were also known to have been used in Sumeria in Mesopotamia, now (modern day Iraq) during the Late Bronze Age (1500 B.C.) and multi-tube drills were used in China during the Qin Dynasty.

The introduction of Tull's improved seed drill was an early example of the mechanisation of manual labour tasks which ushered in the Industrial Revolution in Britain.

1705 Head of demonstrations at the Royal Society in London, English physicist and instrument maker appointed by Isaac Newton, Francis Hauksbee the Elder demonstrated an electroluminescent glow discharge lamp which gave off enough light to read by. It was based on von Guericke's electric generator with an evacuated glass globe, containing mercury, replacing the sulphur ball. It produced a glow when he rubbed the spinning globe with his bare hands. The blue light it produced seemed to be alive and was considered at the time to be the work of God. Like von Guericke, Hauksbee never realised the potential of electricity. Instead, electric phenomena were for many years the tool of conjurors and magicians who entertained people at parties with mild electric shocks, producing sparks or miraculously picking up feathers.

1709 Abraham Darby, from a Quaker family in Bristol established an iron making business at Coalbrookdale in Shropshire introducing new production methods which revolutionised iron making. He already had a successful brass ware business in Bristol employing casting and metal forming technologies he had learned in the Netherlands and in 1708 he had patented the use of sand casting which he realised was suitable for the mass production of cheaper iron pots for which there was a ready market. The purpose of his move to Coalbrookdale which already had a long established iron making industry was to apply these technologies and his metallurgical knowledge to the iron making business to produce cast iron kettles, cooking pots, cauldrons, fire grates and other domestic ironware with intricate shapes and designs.

Early blast furnaces used charcoal as the source of the carbon reducing agent in the iron smelting process, but Darby investigated a the use of different fuels to reduce costs. This was partially out of necessity since the surrounding countryside had been denuded of trees to produce charcoal to fuel the local iron making blast furnaces, but there was still a plentiful local supply of coal as well as iron ore and limestone. He experimented with using coal instead of charcoal but the high sulphur content of coal made the iron too brittle. His greatest breakthrough was the use of coke, instead of charcoal, which produced higher quality iron at lower cost. It could also be made in bigger blast furnaces, permitting economies of scale.

See the following Footnote about Iron and Steel Making.

Abraham Darby founded a dynasty of iron makers. His son, Abraham Darby II, expanded the output of the Coalbrookdale ironworks to include iron wheels and rails for horse drawn wagon ways and cylinders for the steam engines recently invented by Newcomen some of which he used himself to pump water supplying his water wheels. His grandson, Abraham Darby III, continued in the business and was the promoter responsible for building the world's first iron bridge at Coalbrookdale.

The mass production of low cost ironware made possible by Abraham Darby's iron making process was a major foundation stone on which the subsequent industrialisation of Britain and the Industrial Revolution were based.

  • Footnote
  • Some Key Iron and Steel Making Processes

    • Smelting is the high temperature process of extracting iron or other base metals such as gold, silver and copper from their ores. The principle behind the iron making or smelting process is the chemical reduction of the iron ores which are composed of iron oxides, mainly FeO, Fe2O3, and Fe3O4 by heating them in a furnace, together with carbon where the carbon burns to form carbon monoxide (CO), which then acts as the reducing agent in the following typical reaction. The process itself is exothermic which helps to maintain the reaction once it is started.
    • 2C + O2 →   2CO

        Fe2O3 + 3CO →   2Fe + 3CO2

      In early times the carbon was supplied in the form of charcoal. Nowadays coke is used instead. Iron ore however contains a variety of unwanted impurities which affect the properties of the finished iron in different ways and so must be removed from the ore or at least controlled to an acceptable level. A flux such as limestone is often used for this "cleaning" purpose. By combining with the impurities it forms a slag which floats to the top and can be removed from the melt.

    • Casting is the process of pouring molten iron or steel into a mould and allowing to solidify. It is an inexpensive method of producing metal components in intricate shapes or simple ingots. Moulds must be able to withstand high temperatures and are usually made from sand with a clay bonding agent to hold it together. The cavity in the mould is formed around a wooden pattern which is removed before pouring in the hot metal.
    • Forging is the process of shaping malleable metals into a desired form by means of compressive forces. It was a skill used for many centuries by blacksmiths who heated the metal in a forge to soften it, then beat it into shape using a hammer. Modern day forging uses machines such as large drop-forging hammers, rolling mills, presses and dies to provide the necessary compression of the work piece. Because these machines can exert very high forces on the work piece, it is also possible to work with cold, unheated metals in some applications. The forging process is not suitable for shaping cast iron because it is brittle and likely to shatter.
    • Swaging is a special case of forging, often cold forging, to form metal, usually into long shapes such as tubes, channels or wires by forcing or pulling the workpiece through a die or between rolls. It is also the method used to form a lip on the edge of sheet steel to provide stability or safety from injury from sharp metal edges.
    • See how gun barrels were manufactured by swaging.

    • Heat Treatment
    • Heat treatment is the black art practiced by blacksmiths for hundreds of years of manipulating the properties of steel to suit different applications. These are the tools they have used.

      In its simplest form, steel is an alloy of iron and carbon and these two elements can exist in several phases which can change with temperature. The mechanical properties of the steel depend on the carbon content and on the structure of the alloy phases present. Heat treatment is concerned with controlling the phases of the alloy to achieve the desired mechanical properties. There are two critical temperatures between which phase changes occur, namely 700°C and 900°C

      The basic phases and phase changes in normal cast steel are as follows:

      • Steel at normal working temperature (below 700°C) is made up from pearlite which is a mixture of cementite and ferrite (iron). Iron on its own is very soft.
      • Cementite is a name given to the very hard and brittle iron carbide Fe3C which is iron chemically combined with carbon.
      • Above the critical temperature of 700°C a structural change takes place in the alloy and the carbon in the pearlite dissolves into the iron to form austenite which is a hard and non-magnetic, solid solution of carbon in iron.
      • If the temperature of the steel cools normally below the 700°C critical temperature, the transformation is reversed and the slow cooling austenite is transformed back into pearlite.
      • If however the austenite is cooled very quickly by suddenly quenching it in cold water or other cold fluid, the transformation does not have time to take place before the temperature of the alloy falls below the critical temperature. The lower transformation temperature thus prevents the transformation to pearlite and instead tends to freeze the composition of the austenite at a temperature below the crtitical temperature. This transforms the ferrite solution into very hard martensite in which the ferrite is supersaturated with carbon. Martensite is too hard and brittle for most applications.
      • Quenching at intermediate temperatures results in a mix of martensite and pearlite leaving the steel with an intermediate hardness level.

      These transformations are exploited in the following processes:

    • Hardening - Steel can be hardened by heating it to above the crtitical temperature and suddenly quenching it in a cold liquid to produce martensite
    • Annealing - Steel can be softened to make it more workable by heating it to above the critical temperature to form austenite, then letting it cool down slowly to form pearlite. This process is also used to relieve work hardening stresses and crystal dislocations caused during machining or forming processes on the steel.
    • Tempering - The level of hardness or maleability of the steel can be set at any intermediate level between the extremes of the hard martensite and the soft pearlite to produce steel with properties tailored for different applications, from cutting tools to springs, by quenching the steel at the appropriate temperature. Starting with hard martensite, the temperature is gradually increased so that it is partially changed back to pearlite reducing its hardness and increasing its toughness. The workpiece is quenched or allowed to cool naturally when the desired temperature has been reached.

    The traditional method used for centuries for judging the temperature at which quenching should occur was by means of colour changes on the polished surface of the steel as it is heated. As the steel is heated an oxide layer forms on its surface causing thin-film interference which shows up as a specific colour depending on the thickness of the layer. As the temperature increases the thickness of the oxide layer increases and the colour changes correspondingly so that for very hard tool steel the workpiece is quenched when the colour is in the light to dark straw range (corresponding to 230°C to 240°C), whereas for spring steel the steel may be quenched when the colour is blue (300°C). Nowadays, for major tempering processes the temperature is measured by infrared thermometers or other instruments however the traditional method is still widely used for small jobs.

    • Case Hardening
    • It is difficult to achieve both extreme hardness and extreme toughness in homogeneous alloys. Case hardening is a method of obtaining a thin layer of hard (high carbon) steel on the surface of a tough (low carbon) steel object while retaining the toughness of its body. Essentially a development of the ancient cementation process for carbonising iron, it involves the diffusing of carbon into the outer layer of the steel at high temperature in a carbon rich environment for a pre-determined period and then quenching it so that the carbon structure is locked in.

    Summary of Iron and Steel Making Processes and What They Do

      • Bloomery - Low temperature furnace. Converts iron ore into wrought iron.
      • Cementation Process - Low temperature furnace. Converts wrought iron into steel by diffusion of carbon.
      • Blast Furnace - High temperature furnace. Converts iron ore into pig iron.
      • Puddling - High temperature furnace. Converts pig iron into wrought iron.
      • Casting - High temperature furnace. Moulds molten iron and steel output into useful shapes.
      • Forging - Mechanical process. Forms steel ingots into useful shapes.
      • Heat Treatment - Low temperature process. Changes the mechanical properties of the steel.
      • Crucible Process - High temperature, low volume process. Purifies and strengthens low quality steel. Also used to create special steels and alloys.
      • Bessemer Converter - High temperature furnace. Converts pig iron into steel
      • Open Hearth (Siemens) Furnace - High temperature furnace. Converts pig iron and scrap iron into steel
      • Electric Arc Furnace - Converts scrap iron and steel into steel.

    Iron and Steel Properties

    • Wrought Iron
    • Wrought iron was initially developed by the Hittites around 2000 B.C. In early times in Europe the smelting process was carried out by the village blacksmith in a simple chimney shaped furnace, constructed from clay or stone with a clay lining, called a bloomery. Gaps around the base allowed air to be supplied by means of a bellows blowing the air through a tuyère into the furnace. Charcoal was both the initial heat source and the carbon reducing agent for extracting the iron from the ore. Once the furnace was started the iron ore and more charcoal were loaded from the top to start and maintain the chemical reaction. It was not usually possible with this method to achieve a temperatures as high as 1300°C, the melting point of iron, but it was sufficient to heat up the iron ore to a spongy mass called a bloom, separating the iron the from the majority of impurities in the iron ore but leaving some glassy silicates included in the iron. If the furnace temperature was allowed to get too high the bloom could melt and carbon could dissolve into the iron giving it the unwanted properties of cast iron.

      Once the reduction process was complete the bloom was removed from the furnace and by heating and hammering it, the impurities were forced out but some of the silicates remained as slag, which was mainly calcium silicate, CaSiO3, in fibrous inclusions in the iron creating wrought iron (from "wrought" meaning "worked"). Wrought iron has a very low carbon content of around 0.05% by weight with good tensile strength and shock resistance but is poor in compression and the slag inclusions give the iron a typical grained appearance. Being relatively soft, it is ductile, malleable and easy to work and can be heated and forged into shape by hammering and rolling. It is also easy to weld.

      Because of the manual processes involved, wrought iron could only be made in batches and manufacturing was very costly and difficult to mechanise.

    • Cast Iron
    • Cast iron was first produced by the Chinese in the fifth century B.C.. The process of smelting iron ore to produce cast iron needs to operate at at temperatures of 1600°C or more, sufficient to melt the iron. To produce the higher temperatures the bloomery furnace technique was upgraded to a blast furnace by increasing the rate of oxygen supply to the melt by means of a blowing engine or air pump which blasted the air into the bottom of a cone shaped furnace. Early blowing engines were powered by waterwheels but these were superseded by steam engines once they became available. To remove or reduce the impurities present in the ore, limestone (CaCO3), known as the flux was added to the charge which was continuously fed into the furnace from above. At the high temperatures in the furnace the limestone reacts with silicate impurities to form a molten slag which floats on top of the denser iron which sinks to the narrow bottom part of the cone where it can be run off through a channel into moulded depressions in a bed of sand. The slag is similarly run off separately from the top of the melt. Because metal ingots created in the moulds which receive molten iron from the runner resembled the shape of suckling pigs, the iron produced this way is known as pig iron. An important feature of the blast furnace is that it enables cast iron to be made in a continuous process, greatly reducing the labour costs. Stopping, cooling and restarting a blast furnace however involves a major refurbishment of the furnace to get it back into operation agin and great efforts are usually made to avoid such a disruption.

      Iron produced in this way has a crystalline structure and contains 4% to 5% carbon. The presence of the carbon atoms impedes the ability of the dislocations in the crystal lattice of the iron atoms from sliding past one another thus increasing its hardness. Pig iron is so very hard and brittle, and very difficult to work that it is almost useless. It is however reprocessed and used as an intermediate material in the production of commercial iron and steel by reheating to reduce the carbon content further or combining the ingots with other materials or even scrap iron to change its properties. Iron with carbon content reduced to 2% to 4% is called cast iron. It can be used to create intricate shapes by pouring the molten metal into moulds and it is easier to work than pig iron but still relatively hard and brittle. While strong in compression cast iron has poor tensile strength and is prone to cracking which makes it unable to tolerate bending loads.

    • Steel
    • Steel is iron after the removal of most of the impurities such as silica, phosphorous, sulphur and excess carbon which severely weaken its strength. It may however have other elements, which were not present in the original ore, added to form alloys which enhance specific properties of the steel. Steel normally has a carbon content of 0.25% to 1.5%, slightly higher than wrought iron but it does not have the silicate inclusions which are characteristic of wrought iron. Removing the impurities retains the malleability of wrought iron while giving the steel much greater load-bearing strength but is an expensive and difficult task.

      Cast steel can be made by a variety of processes including crucible steel, the Bessemer converter and the open hearth method and thus may have a range of properties. See steelmaking summary above.

      Other alloying elements such as manganese, chromium, vanadium and tungsten may be added to the mix to create steels with particular properties for different applications. By controlling the carbon content of the steel as well as the percentage of different alloying materials, steel can be made with a range of properties. Examples are:

      • Blister Steel was a crude form of steel made by the cementation process, an early method of hardening wrought iron. It is now obsolete.
      • Mild steel the most common form of steel which contains about 0.25% carbon making it ductile and malleable so that it can be rolled or pressed into complex forms suitable for automotive panels, containers and metalwork used in a wide variety consumer products
      • High carbon steel or tool steel with about 1.5% carbon which makes it relatively hard with the ability to hold an edge. The more the carbon content, the greater the hardness
      • Stainless steel which contains chromium and nickel which make it resistant to corrosion
      • Titanium steel which keeps its strength at high temperatures
      • Manganese steel which is very hard and used for rock breaking and military armour
      • Spring steel with various amounts of nickel and other elements to give it very high yield strength
      • As well as others specialist steels such as steels optimised for weldability

      Mild steel has largely replaced wrought iron which is no longer made in commercial quantities, though the term is often applied incorrectly to craft made products such as railings and garden furniture which are actually made from mild steel.

    Iron and Steelmaking Development Timeline

    Steel making has gone through a series of developments to achieve ever more precise control of the process as well as better efficiency.

1712 English blacksmith Thomas Newcomen built the world's first practical steam engine capable of doing dynamic mechanical work, not just pumping. It was an atmospheric engine using a piston to produce reciprocating motion. (See diagram of Newcomen's Steam Engine)

In its simplest form, a piston with a fixed connecting rod protruding from the top was mounted in a vertical cylinder above a water boiler. Steam from the boiler introduced at the bottom of the cylinder through a valve pushed the piston up to the top of its stroke. At the top of the stroke, the steam was shut off and the valve was closed trapping the steam inside. As in Savery's engine the cylinder was then cooled, in this case by spraying cold water into the cylinder under the piston to condense the steam. This is the power stroke of the piston in which condensing the steam creates a vacuum under the piston which pulls it back down to its bottom position, or in other words, the atmospheric pressure on the top of the piston pushes it down against the vacuum. This is what gives the engine the name of atmospheric engine.

The fixed piston connecting rod executed a reciprocating linear movement which could be harnessed to perform work.

In practical engines the piston rod was connected to one end a heavy beam balanced on a pivot above the engine. The power stroke of the piston produced a rocking motion of the beam pulling the end of the beam down while at the same time raising the other end of the beam. A second rod connected to the opposite end of the rod from the piston could be used to lift weights or water from great depths, however the actual lifting distance was limited by the stroke of the piston. The piston did not need high steam pressure to raise it to the top of its stroke because the unbalanced heavy weight of the lifting gear on the other end of the beam would tend to pull the piston upwards.

Before Newcomen, water pumps were horse drawn and were effective to a maximum depth of 90 feet (27 M). Newcomen's engine could draw water from several hundred feet enabling the operation of much deeper mines.

Because of the low operating steam pressures the engine was relatively safe. Efficiency however was very low because of the energy needed to reheat the steam chamber with every stroke and the time needed for heating and cooling it. Newcomen's first engine made twelve strokes per minute and raised ten gallons (45 Litres) of water per stroke. It was another 57 years before the next innovation in steam power, James Watt's separate steam condenser.

Because of the high consumption of coal to fuel the engine and its high cost, Newcomen engines were generally found only at pit heads where they were used for draining deep mines.

1713 Prolific French scientist and entomologist René-Antoine Ferchault de Réaumur invents spun glass fibres. In an attempt to make artificial feathers from glass he made fibres by rotating a wheel through a pool of molten glass, pulling out threads of glass where the hot, thick liquid stuck to the wheel. His fibres were short and fragile, but he predicted that spun glass fibers as thin as spider silk would be flexible and could be woven into fabric.

In 1731 Réaumur also invented an alcohol thermometer and a corresponding temperature scale which both bear his name. The temperature scale assigned zero degrees to the freezing point of water and eighty degrees its boiling point. The freezing point was fixed and the tube graduated into degrees each of which was one-thousandth of the volume contained by the bulb and tube up to the zero mark. It was an accident dependent on the expansion of the particular quality of alcohol employed which made the boiling point of water 80 degrees.

1714 The first mercury thermometer was made by Polish inventor Gabriel Fahrenheit. It had improved accuracy over the alcohol thermometer due to the more predictable expansion of mercury combined with improved glass working techniques. At the same time Fahrenheit introduced a standard temperature scale based on the two fixed points of the freezing and boiling points of water.

1714 The British government established the Board of Longitude (BOL) and passed the Longitude Act which offered financial rewards of up to £20,000 (Almost £4 million in today's money) for anyone who could find a simple and practical method for the precise determination of a ship's longitude. The requirement was originally defined as a longitude error of less than 0.5° or 30 arc minutes after a journey from Britain to any port in West Indies (lasting about six weeks).

The initiative was in response to a number of maritime disasters attributable to serious navigation errors. These included the Scilly naval disaster of 1707 in which four ships of the British fleet commanded by Admiral Sir Cloudesley Shovell were wrecked on the treacherous rocks off the coast of the Scilly Isles with the loss of almost 2000 sailor's lives including that of the Admiral himself.

At the time, there were rudimentary ways of determining latitude, the North-South position on the Earth, but there was no accurate way of determining longitude, the East-West position. Dead Reckoning was the method used and this involved calculating the current position by using a previously determined position, or fix, and plotting the new position based upon the vessel's known or estimated speeds and the elapsed time and headings over the course. Apart from the difficulty of measuring the speed of a sailing ship, this method was also subject to serious cumulative errors. The cause of the disaster was blamed on the navigators' inability to determine their longitude. Shovell's ships however, entering the English channel from the South, were also many miles in latitude North of their expected course when they hit the Scilly Isles and besides this, the precise location of the Scilly Isles was not known. But the navigators did not live to tell their tale since there were no survivors and there was a pressing need to do something about finding a better way to determine longitude.

Over the subsequent years this generous longitude prize seemed always out of reach as the original 1714 Act was followed by a series of new Longitude Acts which revised or added conditions for claiming the prize and the full prize money was never paid out. The man who eventually claimed the prize, albeit in installments with the balance paid by parliament in 1773, was Yorkshire born carpenter John Harrison who worked for over three decades on solving the problem.

See also alternative methods of determining longitude.

Using a Chronometer to Determine Longitude

The idea of using a clock to determine longitude was first proposed in 1553 by Dutch cartographer Gemma Frisius.

  • In principle it was easy
  • An observer's East-West position is measured with reference to lines of longitude, or meridians which run between the North and South Poles.

    Since the Earth rotates at a steady rate of 360° per day, or 15° per hour, there is a direct relationship between solar time and longitude. (Solar time is the precise time, at a given location, calculated with reference to the apparent position of the Sun. Local time is usually considered to be the same time across an extensive time zone.)

    As the Earth revolves, the Sun's position in the sky, as seen at noon from a fixed reference point, appears to move West, at the same time declining in elevation. In one hour, the Earth will have rotated by 15° but the Sun's position is fixed. During the same hour, to an observer 15° longitude West from the original location, the Sun will appear to be arriving from the East and at the end of the hour, rising to its maximum elevation which is the local noon. At the time of this local noon, a clock at the original, reference location will indicate an elapsed time of one hour.

    By convention, the fixed reference point of 0° for longitude measurements was set on the Prime Meridian, an imaginary line running between the Poles and passing through Greenwich near London, and the reference time was known as Greenwich Mean Time (GMT) or more recently Coordinated Universal Time (UTC) or Zulu Time by the Military. The scale of longitude ranges from 0° at the prime meridian to +180° eastward and −180° westward.

    Thus the difference between the apparent local solar time at any location in the world and GMT can be used to calculate the longitude with each minute of time difference corresponding to 0.25°, or 15 arc minutes difference in longitude equivalent to 15 nautical miles at the equator.


    • The length of the nautical mile was defined in terms the scale of longitude and the circumference of the Earth at the equator. The 360 degrees of longitude correspond to 360*60 = 21.600 arc minutes and one nautical mile was defined as being equivalent to one minute of longitude at the equator.
    • Measured in statute miles, the circumference of the Earth at the equator is 24,901 miles. Thus 1 nautical mile ≡ 1.15 statute miles.

    • At any latitude above or below the equator, the longitude lines get closer together as the diameter of the Earth decreases with increasing latitude so that the East-West distance corresponding to one degree of longitude decreases from one nautical mile at the equator to zero at the Poles.
      • Example 1 The latitude of Greenwich is 51.48° North. At this latitude the circumference of the Earth is 13,504 nautical miles and one minute of longitude will correspond to 0.625 nautical miles.
      • Example 2 To win the BOL's top longitude prize of £20,000, after an Atlantic crossing to Barbados, situated at 13.19° North, the 30 arc minute longitude error allowed would correspond to a timing error of 2 minutes in time or 29.2 nautical miles (33.7 miles) error in position.
      • For a six week journey, the average timing error (gain or loss) of the ship's chronometer must be less than 2.8 seconds per day to meet the target timing error of less than 2 minutes.

    • The above calculations assume that the Earth's orbit is circular, but the orbit is actually elliptical, not circular so that adjustments must be made from navigation tables.

  • In practice it was difficult
  • Finding the apparent local time was relatively easy by setting the local noon at the time when the Sun was at its highest elevation. The difficulty was in determining the time at a distant reference point such as GMT while on a ship many weeks or months away from port. At that time, the best timekeepers were pendulum clocks but such clocks were useless at sea. There were no clocks that could maintain accurate time during long sea journeys while being subjected to the rolling, pitching and yawing of a sailing ship.

  • Accuracy
  • A timing error of one minute in either the ship's chronometer, or the local measurement of solar time, will result in an error in the longitude measure of 15 arc minutes, no matter how close to, or how far the ship is from its reference point (such as the Greenwich Meridian) and no matter what course the ship has followed to its current location. The major influence is the elapsed time between synchronising the chronometer with the reference time (e.g. GMT) and the current solar time. This is because the timing error of the chronometer is cumulative over time. The longer the ship is at sea, the more the inaccuracy of its longitude measurements.

Harrison's Early Clocks

Self-taught John Harrison was brought up in the small village of Barrow in Lincolnshire. An independent minded outsider throughout his life, he was driven by a passion to produce the most accurate and reliable timekeepers and a sheer determination to succeed. For fifty years he produced a series of innovative advances in timekeeping technology culminating with his recognition for solving the longitude problem.

He completed his first pendulum clock in 1713 when he was only 19 years old. Clock making and repairing were initially however only his spare time activities as he followed his father's trade as a carpenter and he did not take up the challenge of designing a marine chronometer in 1714 when the longitude prize was announced. It is not known whether he was even aware of the prize at the time.

Isolated and far from Britain's clockmaking community, his first clocks made before 1720 were all pendulum clocks and used conventional anchor escapements but apart from that they were far from conventional being made almost entirely of wood including the frame, gear wheels and pinions. Three of these clocks have survived and are held in UK collections at the Worshipful Company of Clockmakers and the Science Museum in London and and Nostell Priory near Wakefield.

The Brocklesby Park Clock

A major step forward was the commission to build an outdoor turret clock for the stables of the Earl of Yarborough. A serious issue with early clocks and watches was friction which caused the mechanisms to slow down. Friction also causes wear which leads to erratic tumekeeping. The solution was lubrication, but this brought its own serious problems. Lubrication reduced the friction for a short period but early lubricants were derived from animal fats which soon deteriorated and thickened with age gathering dust and clogging up the gears. The Brocklesby Park Clock was designed to run without lubrication with minimal friction.

Its unique features included:

  • The use of lignum vitae, a dense oily tropical hardwood, for bearings reduced friction and eliminated the need for lubrication.
  • Gear wheels of oak and box wood, except for the escape wheel which was brass.
  • Gear teeth in small groups mortised into the rim of the gear wheels with the grain in a radial direction to provide maximum strength.
  • A specially designed grasshopper escapement which eliminated the friction between sliding parts by means of a spring mechanism which caused the pallets to jump clear of the escape wheel and thus avoid the need for lubrication.
  • The main driving pinion was in the form of a lantern gear with teeth in the form of tiny lignum vitae rollers, mounted on brass pins so that the teeth made rolling contact with the mating gear wheel.

The clock was finished in 1722 and is still working today in its original location above the stables. Amazingly after almost 300 years of continuous working, it has still not been oiled.

Precision Long Case Clocks

Beginning 1725, working with his younger brother James, Harrison continued the quest for better timekeeping with the design of three long case (grandfather) clocks. His next major innovation in 1726 was temperature compensation which he implemented in these clocks.

Huygens had shown in 1656 that the period of a pendulum is proportional to square root of its length. Harrison was aware that increasing temperature would cause the length of a pendulum to increase and thus cause a clock lose time. He therefore devised the gridiron pendulum using two metals with different coefficients of expansion, arranged in such a form that the metal with the greatest expansion would expand in the opposite direction compensating for the expansion in the other metal so that the length of the pendulum was held constant and the clock kept good time. See a diagram of the gridiron pendulum.

The timekeeping accuracy of these clocks was so good that there were no reference timers accurate enough to measure their performance. He therefore had to check their timekeeping accuracy against apparent star movements. For this he noted the time when a reference star passed behind a fixed object (his neighbour's chimney stack) on subsequent nights. Sidereal time is the time based on the Earth's rotation relative to fixed stars rather than the Sun's orbital position and is easier to observe than the bright Sun. A mean sidereal day is 23 hours, 56 minutes and 4 seconds long, which means that a reference star would pass behind the chimney 3 minutes and 6 seconds earlier each day providing Harrison with a very precise timing reference.

He determined that his three clocks achieved the astonishing accuracy of one second error per month, far exceeding the accuracy of a few seconds error per day achieved by the best London clocks of the day.

Their accuracy was also many times better than the 2.8 seconds per day accuracy needed to win the longitude prize which no doubt piqued Harrison's interest. If only he could get rid of the troublesome pendulum!

Harrison's Clockmaking Resources

Harrison achieved his remarkable developments with the most meagre of resources.

  • There were no simple mathematics to analyse the dynamic performance of the moving parts of the clock mechanisms when subject to random external forces.
  • There were no published data on the performance of materials and structures such as, tensile strength, elasticity, coefficient of expansion or the affects of temperature, humidity and mechanical shock.
  • The lack of published data meant that he had to generate the data himself or proceed by "trial and error".
  • Without data and analytical tools it was easy to be diverted down blind alleys.
  • There were no high performance materials such as plastics or lubricants.
  • The materials which were available were of variable quality.
  • He had to make every single component himself including, gear wheels, springs, screws, spindles, bearings, casings, mounting plates, winders, pointers, pendulum rods and mounts, even the links in the fusee chains.
  • Tools in Harrison's time were still quite rudimentary and like all craftsmen of the period, he had to make his own. It was another century before the simple twist drill bit was invented.
  • With the only means of making precise timing measurements being by the observations of star movements at night, it could take weeks to verify the effect of minor adjustments.
  • All of these issues meant that progress was extremely slow.

Countering all these shortcomings, the greatest resource was Harrison himself.

  • He was innovative, self reliant and doggedly determined. If he encountered a technical problem he would design an alternative solution to avoid it, but if this was not possible he would design a method to compensate for it. His quest for the perfect, friction free timekeeper was never ending.

Harrison's Marine Chronometers

By 1728 nobody had come up with a viable solution to the longitude problem and the Longitude Prize was still unclaimed. The best portable timekeepers of the day were watches and their accuracy was worse than one minute per day while Harrison's pendulum clocks were capable of better than one second per month. Harrison was confident that he could produce a portable ship's clock which could meet the Board of Logitude (BOL) requirement of 2.8 seconds per day and set to work on plans for such a clock. He took the plans to London, his first ever trip South, to seek funding from the BOL and the advice and support of Edmond Halley the Astronomer Royal and member Board.

The BOL members included 6 top navy men, the potential users, 12 members of parliament who looked after the nation's purse strings and 6 top astronomers, mathematicians and academics to assess the technical merits of the proposed solutions. Halley warned that this, latter, technical group favoured astronomical navigation methods and were not well disposed to mechanical devices and while he was sympathetic, he advised Harrison to seek funding elsewhere and suggested that he visit George Graham, the country's foremost clock maker. Despite having his own deadbeat escapement which rivalled Harrison's grasshopper design, and having failed in his own attempts to produce a working temperature compensation design himself, Graham was helpful and lent Harrison £200, interest free, to start work on his ship's clock. Halley also remained an important supporter of Harrison.

Over a period of 30 years Harrison produced a series of four different marine chronometers, later designated as H1 to H4 and a copy H5. See photographs of Harrison's Marine Chronometers

H1 Chronometer

Harrison's first chronometer, H1, was started in 1730 and completed in 1735. The objective was to make a seagoing version of his wooden pendulum clocks. He retained the wooden gear wheels with anti-friction bearings and roller lantern pinions as well as the grasshopper escapement. The rest of the ideas were all new.

  • To make the machine completely independent of gravity and the motion of a ship, it was spring-driven, with all moving parts counterbalanced and controlled by springs.
  • The main driving power came from two mainsprings spaced 180° apart connected through a single fusee (see diagram) to even out variations in the spring forces of the two springs and to minimise the unbalanced force on the fusee.
  • The main gear wheels rotated on unusual friction free "open" balanced roller bearings of Harrison's own design.
  • The pendulum was replaced by a timing oscillator consisting of two 5 pound, dumbbell shaped rocking bar balances linked together by cross wires and oscillating opposite eachother in anti phase so that the effects of the rolling motion of the ship on one bar would be compensated by the effects on the other bar.
  • Two helical springs connecting the upper ends of each dumbbell bar and another pair connecting the lower ends provided the impulse and restoring forces to keep the dumbbells in motion.
  • Temperature compensation was provide by attaching each balance spring by a lever to a version of the gridiron compensator, the first ever application in a balance spring regulator.
  • Harrison also invented the going fusee, a mechanism for the H1 which kept it going while being wound up. Known more generally as maintaining power it has been used extensively in spring-driven clocks and watches ever since.

The H1 was made from 1,440 parts, over 5,400 if the chain links are included, and weighed 34 Kg.

In use it was mounted on gimbals and ran for 38 hours on one winding.

H1 Chronometer Sea Trials

Sea trials were belatedly arranged by the Admiralty in 1736 with a journey to Portugal rather than the specified West Indies necessary to claim the prize.

The clock did not perform well in rough seas during the one week outward journey in rough seas to Lisbon and Harrison even less so being seasick the whole time. The return journey which took one month in mixed weather was more successful. When the English coast was sighted, the ship's Master, Roger Wills, and his officers, having used traditional navigation methods identified it as Start Point, just East of their destination, Portsmouth. But Harrison's own chart, plotted using H1, placed them correctly 68 miles further West, at Lizard Point and potentially in peril. By coincidence Will's error was similar to the one which caused the demise of Admiral Shovell who ran into the Scilly Isles 55 miles West of Lizard Point.

The accuracy of Harrison's navigation was acknowledged by Wills who reported positively to the BOL. (The timekeeping accuracy of H1 was subsequently estimated as between 5 and 10 seconds per day). This was not enough to claim the longitude prize, but it was the first workable marine timekeeper and the BOL were sufficiently impressed that in 1737 he was awarded £250 to continue his experiments and the promise of £250 more on successful completion of a second approved machine. This enabled him to start work on H2, a more rugged and compact version of the H1. This was the first ever government sponsored Research and Development programme.

H2 Chronometer

In 1736 Harrison moved to London, closer to the clockmaking community, to start work on H2. It followed the same basic design as H1 using a grasshopper escapement but with all the wooden parts changed to brass and improved gridiron temperature compensation. It ended up being taller and heavier than H1.

It did however have one further innovation. In 1739 Harrison invented the spring remontoire, a more controlled, secondary driving force which improved timekeeping regularity by separating the sensitive escapement from the main driving force thus avoiding variations in the driving force due to the mainspring winding down or caused by small errors in the manufacture. In the H2 the remontoire spring was rewound every 3 minutes 45 seconds.

In 1741, after three years of building and two of testing, H2 was ready for sea trials, but Britain was at war with Spain in the War of Austrian Succession and the trial was postponed because the government deemed that the clock was too important to risk falling into enemy hands. Shortly afterwards Harrison came to the conclusion that the H2, like the H1, was too cumbersome and the slow moving heavy dumbbell balances could not fully cancel all the possible ship's motions as expected. It was reluctantly abandoned and never submitted for sea trials.

In the meantime, he had already started work on a new sea clock, H3, with circular balance wheels instead of the heavy rocking arms, for which he requested, and received, further grant of £500 from the BOL.

H3 Chronometer

Starting in 1740, Harrison spent 19 years working on H3 during which the BOL supported it with grants totalling £3000, before it too was also abandoned.

It was smaller and lighter than the previous two clocks and used a similar grasshopper escapement and a 30 second remontoire, but the large heavy balance wheels were just as susceptible to disturbance by the sea's forces as the previous balance bars. Another major difficulty was the lack of detailed theoretical knowledge of the properties of springs. It was not until 1807 that the notion of elasticity was defined and quantified by Thomas Young. The H3's two balance wheels were mounted one above the other and linked together by cross wires. A single, short, spiral balance spring controlled the upper wheel only in place of the four helical springs controlling the balance bars of the H1 and H2 and Harrison was unable to get this mechanism to work isochronously so that he was unable to achieve the necessary timekeeping accuracy.

Nevertheless, during this development period Harrison invented two new mechanisms for the H3 which are still used today. These were:

  • The Caged Roller Bearing in which the wheel shaft rotates between four bronze rollers held in a light brass cage so that there is only rolling motion and no sliding friction between the shaft and the bearing. This was the forerunner of the ubiquitous modern ball bearing.
  • The Bimetallic Strip which Harrison called his "thermometer curb". Constructed from brass and steel it bends under the influence of temperature, (See diagram) and this movement was used to shorten or increase the length of the balance spring. Shortening the length of the spiral spring increases its stiffness and compensates for the weakening of the spring as the temperature increased. Increasing the spring's length to compensate for the cold has the opposite effect.

The "Jefferys" Watch

While still struggling with the H3, in the early 1750s Harrison turned his attention to watches and designed a precision watch for his own personal use, which was made for him by the watchmaker John Jefferys. Completed in 1753, it used a novel vertical, recoil free, frictional rest escapement, similar to the verge balance spring escapement and was the first to incorporate in a watch some of the innovations developed for Harrison's clocks including temperature compensation and the going fusee.

Surprised by the accuracy of the watch's timekeeping, he began to realise that for over 20 years he had been working on the wrong track with his three sea clocks and that a watch would better satisfy the BOL requirements for a "practical" solution. He came to the conclusion that the secret to stability was small high frequency oscillators and that the large heavy balances in his sea clocks could not oscillate quickly enough to ensure stable timekeeping and that a smaller watch could oscillate at a much higher speed. This was one of Harrison's great insights.

He therefore admitted defeat and turned his attention to the design of a sea watch, H4.

H4 Chronometer

In 1755 Harrison requested a further grant from the BOL to complete the H3 and to produce two sea watches, the H4 plus a smaller version. The BOL, still supporting the project, approved a grant of £2,500.

The H4 Sea Watch is housed in a silver case 13 cm (5.2 inches) in diameter like a large pocket watch and weighs 1.45 kg. It was based on Harrison's "Jefferys" Watch with the following innovations:

  • It had a high energy isochronous escapement which made it less affected by the slower ship's motions. This was accomplished by means of a heavier balance wheel with a greater amplitude swing of ±145° oscillating five times per second so that it carried much more kinetic energy making it less vulnerable to physical disturbance.
  • The escapement was driven by a remontoire, rewinding eight times a minute, to even the driving force.
  • A balance-brake stops the watch 30 minutes before it is completely run down, in order that the remontoire does not run down also.
  • Because the watch was too small to incorporate Harrison's anti-friction devices some of it's bearing surfaces required oil, however wherever possible jewelled (ruby and sapphire) bearings were fitted to reduce friction.
  • Diamonds were used for the surface of the escapement pallets.

In common with the Jefferys Watch it also had temperature compensation by means of a bimetallic strip and maintaining power by means of a going fusee.

The H4 Sea Watch was completed in 1759 and was submitted in 1760 to the BOL for sea trials. They awarded Harrison £250 to prepare and carry out the trials of H3 and H4 on a voyage to Jamaica in 1761. It had taken six years of development and testing.

Rival Methods

Meanwhile, German astronomer, Tobias Mayer had developed an alternative method of determining longitude, originally suggested in 1514 by another German astronomer Johannes Werner. Known as the lunar distances method, it was based on the position of the Moon relative to other fixed celestial bodies. Because the moon orbits the Earth in a regular orbit at around 15 degrees per day, its current position (angle) relative to a reference star, compared to its known position relative to the same reference star, as seen from some other terrestrial reference point such as Greenwich, could be used to calculate the current time difference between the two points. From the time difference, the longitude could be calculated. Unfortunately it took about four hours to perform these calculations by which time the ship would have moved to a new position.

The method only needed a sextant to make the observations and did not need an expensive chronometer.

In 1752 Mayer published initial tables of lunar distances which he had calculated. The latest update of these tables had also been sent in 1755 to Britain's current Astronomer Royal James Bradley who became a staunch advocate of the method. The recent invention of the sextant in 1757 had also improved the practicality of making the necessary celestial measurements, strengthening the case. The sextant was also much less expensive then the chronometer.

Notes: In 1612, Galileo had proposed a much simpler and accurate way of determining longitude based on observations of Jupiter's natural satellites, but such observations were impractical from a ship at sea.

In modern practice, a nautical almanac and nautical tables enable navigators to use the Sun, Moon, visible planets or any of 57 navigational stars for celestial navigation.

In 1760 the Royal Society appointed astronomer, the Reverend Nevil Maskelyne, to undertake an expedition to St Helena to observe the 1761 Transit of Venus with the objective of calculating the distance between the Earth and the Sun. Maskelyne used the opportunity to verify Mayer's method of lunar distances for calculating longitude and after his return he published British Mariner's Guide in 1763 explaining the method and showing some example lunar distances. This was followed by the Nautical Almanac in 1767 in which he provided more comprehensive tables of computed lunar distances from the Moon to the Sun and seven stars, every three hours for the whole of 1767.

Based on the Mariner's Guide, Maskelyne staked his claim for the Longitude prize and was supported by the current Astronomer Royal James Bradley who had succeeded Halley as Astronomer Royal in 1742.

With these developments just beginning in 1760, the astronomers were also preparing their bid for the prize, and the sea trials of the H4 were delayed by Bradley until late 1761. By then Harrison was 68 years old and the H3 and H4 chronometers were sent on their journey to Jamaica in the care of his son William.

H4 Chronometer Sea Trials

It is not unusual for a timekeeper to have a fixed rate of time loss or gain, called the "rate". What is important is that the rate should not vary. If it is fixed it can be allowed for.

Before the trial, the H4 chronometer was calibrated by the Naval Academy at Portsmouth and determined to be 3 seconds slow with a fixed "rate" of time loss of 24/9 seconds per day.

During the first leg of the journey to Madeira, after 9 days out, the ship had run out of key provisions. Harrison predicted landfall the following day but Captain Dudley Digges disagreed, pointing out that, by his calculations, they were over 100 miles from Harrison's position and wagered that he was over 100 miles in error. When land was sighted the following morning, the young Harrison was proved right and Digges honoured his bet and offered to buy the first available chronometer of Harrison's design.

Continuing on their journey, they reached Kingston in Jamaica in 1762 after a total of 81 days and 5 hours at sea while the ship's log showed them to be well over 100 miles away. After allowing for the accumulated daily "rate" of time loss amounting to 3 minutes 36.5 seconds and an initial error of 3 seconds, Harrison's chronometer had lost only 5.1 seconds over the whole period as determined by solar measurements. This corresponded to an error in longitude of only 1.25 arc minutes, or approximately 1 nautical mile, compared with the known longitude of Kingston and well within the BOL requirement of 2 minutes in time or 30 arc minutes (0.5 degrees).

When the ship returned in 1762, Harrison expected to receive the £20,000 prize but he was sorely disappointed. His previous support from the BOL had evaporated. His original supporters Halley and Graham had been dead for several years and the BOL was still dominated by astronomers led by Bradley, the Astronomer Royal, who favoured the lunar distances method of determining longitude. The BOL came up with numerous arguments not to pay and demanded another trial.

  • The results were too good to be true.
  • The demonstrated accuracy was down to luck.
  • A timekeeper which took six years to construct did not meet the test of practicality required.
  • The location of Kingston was not known accurately.
  • The calibrated "rate" loss had not been declared before the voyage, implying that it must have been chosen after the event to fit the desired result.
  • It must have been a fluke.
  • Positive and negative errors had cancelled out.

Their conclusion was that there was insufficient evidence from the sea trials to qualify for the prize and that the chronometer should be subject to a second sea trial to prove the accuracy and viability of the watch.

Harrison was awarded £1,500 for the progress and promised a further £1,000 on completion.

The Second H4 Sea Trial

After much bitter argument it was agreed that he second trial would be a journey to Bridgetown in Barbados. Harrison was given 4 or 5 months to prepare and to calibrate the loss "rate" and the journey would take place in 1764 with the H4 in the care of Harrison's son William.

Much to Harrison's annoyance Maskelyne, his competitor for the prize, was sent to Barbados in 1763 to confirm its exact longitude using observations of Jupiter's satellites and, during the journey, to verify the suitability of Mayer's latest lunar distance tables for determining longitude. Such a conflict of interest would never be allowed today.

Before the journey Harrison gave calibration "rates" from 3 seconds per day gain at 42°F to 1 second per day loss at 82°F or an average of 1 second per day gain.

After a voyage of 47 days the timing error was just 39.2 seconds after the correction for "rate". This was less than one second per day and corresponded to an positional error of 9.8 miles (15.8 km) at 13.19° North, the latitude of Barbados. This was three times better than the performance needed to win the full £20,000 longitude prize.

By comparison Maskelyne's calculations based on lunar distances were also reasonably close with a positional error of 30 miles (48 km) at Barbados but they required several hours of calculations to determine the each position during the journey.

On the ship's return to Portsmouth after a two way journey of 156 days, and applying the average predetermined rate correction of 1 second per day, the watch had gained 54 seconds amounting to a third of a second per day. If the declared variable rate corrections for the temperature changes had been applied, the error would have been less than one tenth of a second per day. Surely enough to claim the prize. But Harrison was to be thwarted once more.

The Final Hurdles

By the time of the BOL review of the trial in 1765, Maskelyne had been appointed Astronomer Royal. In his report about the trials Maskelyne gave a negative report about the watch claiming once again that the accuracy of the measurements was attributed to luck and that the watch did not meet the needs of the BOL. The BOL consequently insisted that Harrison was only eligible for half of the prize money and applied a new set of conditions with which he must comply before he could even be awarded that.

The matter eventually reached Parliament, which offered Harrison £10,000 in advance and the other half once he handed over the design to other watchmakers to duplicate what had originally been considered to be a military secret. In the meantime he must disclose full design details of the mechanism to a BOL scientific committee and the watch would have to be handed over to the Astronomer Royal for long term testing. Eventually he reluctantly agreed and was awarded £7,500 since he had already received £2,500. Mayer was posthumously awarded £3,000 for his lunar distance method and tables.

Maskelyne who had not given up his own claims to the longitude prize, in 1766 produced a government warrant confiscating Harrison's three remaining timekeepers which were to become public property and subject to rigorous testing. Needless to say, they were treated very roughly. H4 had already been dismantled for disclosure to the board and was in need of cleaning and adjustment. After a 10 month trial H4 had gained 1 hour, 10 minutes and 27.5 seconds. Based on this Maskelyne pronounced that the watch could not be relied upon to keep the longitude on a six week journey to the West Indies despite the fact that it had already been demonstrated in twice in practice.

In 1766, in response to Harrison's claims for the second £10,000, the BOL also insisted that he must arrange the production of two copies of the sea watch to prove it was not a fluke. The first, known as K1 was made by watch maker Larcum Kendall and completed satisfactorily in 1769. Kendall had been a member of the BOL's scientific committee who had reviewed the H4 watch. The BOL insisted that the second copy had to be made by john Harrison himself. He was now 73 years old.

In 1767 the BOL published "The Principles of Mr Harrison's Timekeeper" making public the results of over 30 years of his work.

The H5 Chronometer

H5 was the copy of H4 which was demanded by the BOL and it was completed by Harrison in 1772 when he was 79 but the BOL still refused to pay up. The unschooled carpenter from the North was always at a disadvantage when arguing with the capital's aristocracy.

Frustrated and angry, Harrison appealed to the King, George III who was appalled by their treatment. In response he conducted his own private tests on the H5 watch, monitoring it daily. It performed superbly losing only 4.5 seconds in two months. Nevertheless the BOL refused to recognise the results of this independent trial. As a result the King advised John and William, to petition Parliament, threatening to appear in person to support their claim. In June of 1773, by Act of Parliament, the government finally awarded them £8750 which exceeded the balance of the £20,000 still owing.

The Board of Longitude Prize was never awarded.


The development of the first true chronometer was the life's work of one man, John Harrison, who never gave up despite numerous disappointments and setbacks during 31 years of persistent experimentation and testing. Harrison's chronometers revolutionised seafaring in the eighteenth century.

Initially they were very expensive. The K1 cost £450, an enormous sum at a time when the cost of a new ship was only around £10 per ton of displacement, but prices began to fall as chronometer's value was recognised and they became the preferred method for determining longitude.

The K1 was given to explorer Captain James Cook to trial on his three year (second) voyage of discovery to the South Sea Islands and subsequently used by him on his third voyage, having used the lunar distance method for navigation and surveying on his first voyage. He found it exceeded his expectations and became a great advocate for the chronometer. A second copy K2 was used by Lieutenant William Bligh, Captain of HMS Bounty, but taken by Fletcher Christian during his infamous mutiny in 1789.

You can still see Harrison's original sea clocks and watches.

H1, H2, H3, H4, K1 and K2 are displayed at the UK National Maritime Museum, Greenwich, London

H5 is held at the Worshipful Company of Clockmakers in London.

1725 French weaver Basile Bouchon used a perforated paper roll in a weaving loom to establish the pattern to be reproduced in the cloth. The world's first use of manufacturing automation by using a stored program to control an automated machine.

1728 Another French weaver, Jean Falcon worked with Bouchon to improve his design by changing the perforated paper roll to a chain of more robust punched cards to enable the program to be changed more quickly.

1729 English chemist Stephen Gray was the first to identify the phenomenon of electric conduction and the properties of conductors and insulators and the first to transmit electricity over a wire. In an experiment, a young boy across laid across two swings suspended by silk ropes which insulated the boy electrically from the ground. The boy's body was charged up from a Hauksbee machine and when the boy held his hand above flakes of gold leaf on the floor, the flakes were picked up by electrostatic attraction to his hand. Thus electric charge was thus shown to be conducted through the boy's body to his hand but not through the insulating silk ropes to the ground.

Gray subsequently sent charges nearly 300 feet over brass wire and moistened thread and showed that electricity doesn't have to be made in place by rubbing but can also be transferred from place to place with conducting wire. An electrostatic generator powered his experiments, one charge at a time. The fore-runner to the electric telegraph.

1730 The octant, forerunner of the sextant was independently invented by English mathematician, John Hadley, and Thomas Godfrey, an American glazier in Philadelphia. The instruments enabled the precise measurement of the angle between two distant landmarks as seen by the observer. Their prime application however was for navigation where they were used to determine the angle of elevation between a celestial object and the horizon.

The principle of the "reflecting quadrant" or "octant", a doubly reflecting optical instrument, was first described in detail by Isaac Newton in 1699 in a letter to Edmond Halley, Britain's Astronomer Royal, but the description was not published until after Halley's death in 1742. The first sextant was made by London instrument maker John Bird in 1757. It was simply a scaled up version of the octant, requested after sea trials by British Admiral John Campbell who found the octant's 90° measurement range was too restrictive for lunar measurements and asked for it to be increased to 120°.

Mariners had for centuries used the principles of celestial navigation as a basis for determine their latitude by measuring the angle of elevation above the horizon of the Sun at solar noon, or Polaris, the North Star, at night (in the Northern hemisphere), but their instruments, ranging from the cross staff and astrolabe to a simple tilting quadrant scale with a plumb bob, were very inaccurate. They were also difficult to use since while standing on a pitching and rolling ship, the user had to simultaneosly observe the horizon and the target celestial object which both both move around in the observer's field of view.

The sextant, an optical instrument based on two reflecting mirrors, greatly improved the accuracy and simplicity of making these navigation sightings by superimposing the images from the horizon and the target in a single viewfinder. In this way the relative position of the two images remains steady in the viewfinder of the sighting telescope making the observation much easier to manage as the ship pitches and rolls.

The invention of the sextant was a major step in improving safety at sea. Sextants are still used today as emergency back-up in case of failure of modern electronic navigation systems. Unlike GPS satellite navigation systems they are completely autonomous and don't need electricity to get a fix on a position. They are even used for navigation in space where they provide precise calibration for correcting the drift in the guidance system which can occur with spacecraft inertial navigation platforms.

How it Works

The marine sextant enables the observer to view both the horizon and the target celestial object simultaneously. Light from the horizon enters the sextant's sighting telescope directly while light from the target object is directed via a tilting mirror into the same telescope and superimposed on the image of the horizon. By tilting the mirror, the image of the target object can be brought into line with the image of the horizon and the measured angle of tilt is used to derive the angular elevation of the target.

See a diagram of a Sextant illustrating its workings.

The sextant has two lines of sight, one from the horizon and one from the target navigational marker (either the Sun or a star). The line of sight from the horizon, known as the boresight, is a straight line passing along a fixed path directly into the sighting telescope via the transparent half of a "half-silvered horizon mirror" which splits the view horizontally and provides a full view of the horizon. Alternatively the view may be split vertically by means of a "half-horizon mirror" through which the path of the horizon line of sight passes through its clear side.

The line of sight of the target object (the Sun or the star) is reflected from the "index mirror" onto the horizon mirror which in turn redirects it into the sighting telescope so that the images of the target and the horizon are superimposed. By adjusting the angle of the index arm, the image of the target can be lined up with the horizon. The angle of elevation of the target can then be read off from the graduated scale. A 1° movement of the index arm corresponds to a 2° difference in the elevation of the line of sight to the target. This is because the change in the angle between the incident and reflected rays on the index mirror is double the change in the angle of incidence of the rays on the mirror caused by rotating the index arm. (Angle of reflection = Angle of incidence). Thus the scales of the octant which covers an arc of 45° and the sextant which covers an arc of 60° are graduated from zero (or below) to 90° and 120° respectively.

Filter glasses can be moved into the optical paths to reduce the intensity of the Sun's rays in order to protect the user's eyes from harm.

The sextant's graduated scale will indicate the angle of elevation, confusingly called the altitude or the height even though it is measured in degrees, of the target celestial object above the horizon. The apparent position of the Sun in the sky varies with the seasons, in the northern hemisphere being higher in the winter than in the summer and it varies with the time of day being at its highest at noon. The actual latitude must therfore be determined from navigation tables which show the true latitude corresponding to the elevation measured, with correction factors depending on the month and day of the year and on the precise time of the day as registered by the ship's chronometer when the sighting was taken. At the same time the tables also provide the ship's longitude corresponding to the noted chronometer reading. Thus the ship's complete geographical position can be determined.

Finding Latitude Using Polaris

The line of sight to the horizon at any point on the Earth is very close to a tangent to the Earth's surface, (see corrections below).

Polaris is a distant star in the northern sky lying on a line coincident with the axis of the Earth. As the Earth makes its annual orbit around the Sun and makes its daily revolution on its axis, Polaris appears to be stationary in the sky on a line perpendicular to the Earth's equator, passing through the North Pole. It is so far away that light rays impinging on the Earth appear to be parallel.

For an observer situated on the equator, Polaris will appear to be exactly on the northern horizon and the angle of incidence between the horizon and Polaris, its elevation, will be zero since the line of sight of both the horizon and the star are at right angles to the Equator. For an observer at the North Pole, Polaris will appear to be directly overhead with an angle of incidence or elevation at 90° to the line of sight to the horizon. These two elevations correspond to the latitudes at those points. At any intermediate point between the North Pole and the equator, the elevation indicated on the scale of the sextant corresponds directly to the true latitude of the location.

Unfortunately there is no equivalent South Pole Star and alternate methods of determining latitude must be used.

Finding Latitude Using the Sun

Because the reference position of the Sun is in the plane of the equator, the measured angles of elevation will be displaced by 90° from the angles measured using the Polaris reference. Thus at noon on the vernal or autumnal equinox (when the daytime and night time are approximately equal), on the equator (latitude zero) the Sun will be directly overhead and the sextant will indicate the angle of elevation of the Sun to be 90°. At the same time, since the distant Sun's rays are essentially parallel, at the North and South Poles (90° latitude) the Sun will appear to be on the horizon and the sextant will indicate the Sun's angle of elevation to be 0°. At the Poles, and any location in between, the latitude can be determined by subtracting the sextant reading from 90°.

But this is not a practical way of determining latitude since equinoxes occur only two times per year. Using the Sun to determine latitude is much more complicated because the Sun does not appear as a stationary reference target like Polaris does. There are two reasons for this.

The first is that the Earth's axis is tilted at a fixed angle of 23.45° with respect to the plane of its orbit around the Sun so that, as it makes its 12 monthly orbit, the highest position of the noon-day Sun, as seen from the Earth, appears to move between 23.45° above the equator and 23.45° below the equator as the Earth moves between opposite sides of the Sun. See diagram of Earth's tilted orbit.

In the Northern hemisphere, at noon on the summer solstice, (the longest day), the Sun will be directly over the Tropic of Cancer at a latitude of 23.45° North. At noon on the winter solstice, (the shortest day) the Sun will be directly over the Tropic of Capricorn at 23,45° South. These observations are mirrored in the Southern hemisphere.

The apparent position of the Sun or other celestial object above or below the Earth's equator is known as its declination and the solar declination depends on the angular distance of the Earth around its orbit of the Sun, in other words, on the date.

The second variation arises because the Earth is rotating once per day so that the Sun appears from over the horizon at dawn, rising to its highest elevation at noon, then declining and disappearing below the horizon in the evening. Thus the observed elevation of the Sun depends on the time of day. For consistency and simplicity, sightings are normally taken at noon when the Sun appears at its highest position in the sky. At any other time, corrections must be applied for the declination due to the time of day.

True latitudes on any particular day are therefore determined from published navigation tables, which show the solar declination for every day of the year, by applying the following calculation:

  • Latitude = (90° - Sextant Angle) + Declination of the Sun if the observer is in the same hemisphere as the Sun
  • Latitude = (90° - Sextant Angle) - Declination of the Sun if the observer is in the opposite hemisphere from the Sun

Corrections for time and minor corrections for the height of the observer above the Earth's surface must also be applied. Any small perturbations in the Earth's orbit are already taken into account in the basic navigation tables.

Before the availability of accurate chronometers such as those first pioneered by John Harrison, the sextant was also used to determine the time and hence the ship's longitude by measuring the angle between the Moon and other celestial objects, the so called "lunar distance". Because the Moon makes regular orbits of the Earth once every 27.32 days, its position can be used as a timing reference. Greenwich time corresponding to the observed lunar distance could then be found from a nautical almanac and from the difference between the Greenwich time and the local time the longitude could be calculated.


The accuracy of the sextant depends on the precision and skills of the instrument maker. The measurement accuracy of Bird's sextant was 2 arc minutes. This corresponds to a possible latitude error of about 2 nautical miles. Modern sextants typically have an measurement accuracy of around 0.1 arc minutes or 0.1 nautical miles which is about 200 yards. At sea, results within the visual range of several nautical miles are often considered acceptable. There is also the possibility of user set up errors but adjustments are usually provided to correct this.

Correction Factors

Besides the accuracy of the instrument itself, there are several further factors also affecting the accuracy of the measurement. The line of sight to the horizon of the ocean is not a true tangent to the Earth's or the sea's surface, but depends on the height of the sextant telescope, or the observer's eye, above the surface. This correction known as the "dip" must be subtracted from the sextant reading. The dip in arc minutes is given by:

Dip correction = - 1.76√eye height in metres


Dip correction = - 0.97√eye height in feet

Thus for a reading taken 5.5 metres or 18 feet above sea level from the deck of a ship, the dip correction will be - 4.1 arc minutes corresponding to an adjustment in the calculated latitude of 4.2 nautical miles.

There are also slight, recurring irregularites in the movement of the Earth which also introduce potential errors. Another potential correction allows for sighting to be made on the centre or the edge of the Sun. The navigation tables provide compensation for most of these errors.

1733 French soldier, diplomat and chemist Charles-Francois de Cisternay du Fay discovered two types of electrical charge, positive and negative which he called "vitreous" and "resinous" from the materials used to generate the charge.

1733 John Kay of Bury, Lancashire (No relation to John Kay of Warrington) patented the flying shuttle, the device used in weaving looms, which carries the weft threads (across the width of the cloth) between the warp threads (along the length of the cloth). In a traditional hand loom, the weft thread was held in a natural reed which was propelled by hand across the loom between the warp threads pulling the weft behind it along a track called the race. It was a slow process and to produce wide bolts of cloth, it needed two weavers, one at each side of the loom to catch and return the shuttle. In Kay's system, a mechanism at each end of the race caught the shuttle and sent it back to the opposite side. The shuttle itself was made of metal and being heavier than the reed it gave the shuttle more inertia to traverse the loom. This system enabled much faster weaving speeds and the production of greater widths of cloth with only one operator per loom instead of two as well as reduced manual intervention in the process.

The introduction of flying shuttle was however perceived as a threat to their livelihood by textile workers who resisted its introduction and Kay had great difficulty in collecting the royalties on his patents.

On the positive side, the increased production of cloth created a demand for thread which exceeded the industry's production capacity, prompting the mechanisation of the thread spinning process.

The invention of the flying shuttle was one of the first examples of mechanisation being used to improve productivity and a significant first step in the Industrial Revolution.

1733 French Huguenot mathematician, Abraham de Moivre living in England to escape religious persecution in Catholic France derived and published the formula for the Normal Distribution which he used to analyse the magnitude and the probability distribution of errors. Also called the Bell Curve and the Gaussian or error distribution but strangely never by de Moivre's name, besides describing the distribution of measurement errors it is widely used to represent the distribution of characteristics which cluster round a mean value such as the spread of tolerances on manufactured parts to anthropometrical and sociological data about the general population. See diagram of the Normal Distribution.

De Moivre also derived a law relating trigonometry to complex numbers which was indeed named after him. It states that for any complex number and for any real number X and integer n it holds that:

(cosx + i sinx)n = cos(nx) + i sin(nx)

He supplemented his meagre income as a mathematics tutor with a little gambling and the publication of his book The Doctrine of Chances: a method of calculating the probabilities of events in play one of the first books about probability theory which ran into four editions between 1711 and 1756.

1738 Swiss mathematician Daniel Bernoulli showed that Newton's Laws apply to fluids as well as solids and that as the velocity of a fluid increases, the pressure decreases, a statement known as the Bernoulli principle.

More generally the Bernoulli Equation is a statement of the conservation of energy in a form useful for solving problems involving fluid mechanics or fluid flow. For a non-viscous, incompressible fluid in steady flow, the sum of pressure, potential and kinetic energies per unit volume is constant at any point.

Bernoulli's equation also underpins the theory of flight. Lift is created because air passing over the top of the wing must travel further and hence faster that air traveling the shorter distance under the wing. This results in a lower pressure above the wing than below the wing and this pressure difference creates the lift.

See also Diagrams of Aerodynamic Lift and Alternative Theories of Flight

Daniel Bernoulli was also the first to explain that the pressure exerted by a gas on the walls of its container is the sum of the many collisions by individual molecules, all moving independently of each other - the basis of the gas laws and the modern kinetic theory of gases.

Daniel Bernoulli was a member of a family of Bernoullis many of whom gained international distinction in mathematics. They were Calvinists of Dutch origin but were driven from Holland by religious persecution finally settling at Basel in Switzerland.

James (Jacques/Jakob) Bernoulli was the first to come to prominence. He learned about calculus from Leibniz and was one of the first users and promoters of the technique. In his Ars Conjectandi, "The Conjectural Arts" published in 1713, eight years after his death by his nephew Nicholas Bernoulli, he established the principles of the calculus of probabilities - the foundation of probability theory as well as the principles of permutations and combinations. He was also one of the first to use polar coordinates.

John (Jean/Johann) Bernoulli, James' brother and father of Daniel was clever but unscrupulous, fraudulently substituting the work of his brother James, of whom he was jealous, for his own to cover up his errors. He also banished his son Daniel from his home when he was awarded an prize he himself had expected to win. Nevertheless he was a great teacher an advanced the theory of calculus to explore the properties of exponential and other functions.

John's three sons Nicholas, Daniel and John Bernoulli the younger and his two sons John and James all achieved distinction in mathematics in their own right.

1740 British clockmaker Benjamin Huntsman, in search of spring steel for his clock making business, developed the crucible steel process to improve the quality of conventional blister steel which was not uniform and often contained slag and structural dislocations which made it unsuitable for high stress applications. Blister steel, the best quality steel available at the time, was derived from wrought iron, using the cementation process, and had never been in a fully liquid state.

Huntsman's solution was to refine the blister steel by melting it and skimming off the slag to produce homogeneous molten steel which could be poured into moulds to produce high strength, pure cast steel ingots. He chose Sheffield as the location for his business since it had a plentiful supply of good quality coke which was the fuel needed to achieve the very high temperature necessary to melt the steel. Such high temperatures and fine controls had never before been achieved in a practically sized furnaces.

His process involved heating a 34 pound (15 kg) charge of small pieces of blister steel together with a limestone flux to over 1600°C in small covered refractory vessels (fireclay pots) called crucibles for three hours in a coke fire to melt the steel. The crucibles had to be robust enough to withstand the very high furnace temperatures and the ceramic material from which they were constructed should not contaminate the melted steel.

This process eliminated the defects from the steel and, after casting, produced a homogeneous, high tensile strength, high quality steel. The crucible operation required very precise control of the furnace but the small scale of the operation also allowed more precise control of the process than was possible with a large blast furnace. It also allowed other alloying materials to be added to the mix to make specialist steels to precise specifications but the method was slow and labour intensive and only suitable for making small batches. Fuel costs were also very high. After 1870, the coke fired furnaces were replaced by gas fired furnaces.

Huntsman's crucible steel set new standards for the quality of steel. Key to his success were the design and manufacture of the crucibles, the high temperature furnaces and the control of the content of the steel charge, all of which he kept a closely guarded secret.

See also Iron and Steel Making

1744 Prolific French inventor Jacques de Vaucanson maker of robot devices and automatons playing musical instruments and imitating the movements of birds and animals, turned his attention to the problems of mechanisation of silk weaving. Building on the inventions of Bouchon and Falcon, he built a fully automated loom which used perforated cards to control the weaving of patterns in the cloth. Vaucanson also invented many machine tools and collected others which became the foundation of the 1794 Conservatoire des Arts et Métiers (Conservatory of Arts and Trades) collection in Paris. Although Vaucanson's loom was ignored during his lifetime, it was rediscovered more than a half century later at the Conservatoire by Jacquard who used it as the basis for his own improved design.

1745 Electricity first stored in a bottle (literally). The discovery of the Leyden Jar, essentially a large capacitor, was claimed by various experimenters but generally attributed to a Dutch physicist and mathematician Pieter van Musschenbroek and his student Andreas Cunaeus (whom he almost electrocuted with it) working at Leyden University in Holland. The first source of stored electrical energy the Leyden jar was simply a jar filled with water, with metal foil around the outside and a nail piercing the stopper and dipping into the water.

A similar device was also invented at the same time by Ewald Jurgens von Kleist, Dean of the Cathedral of Kammin in Germany.

The design was improved in 1747 by English astronomer John Bevis who replaced the water with an inner metal coating covering the bottom and sides nearly to the neck. A brass rod terminating in an external knob passed through a wooden stopper or cork and was connected to the inner coating by a loose chain or wire.

The invention of the Leyden jar was a key development in the eighteenth century and until the advent of the battery, Leyden jars, together with von Guericke's and Hauksbee's electrostatic generators, were the experimenters' only source of electrical energy. They were however not only made for scientific research, but also as curiosities for amusement. In the 18th century, everybody who had heard of it wanted to experience an electric shock. Experiments like the "electric kiss" were a salon pastime.

1746 French clergyman and physicist Jean Antoine Nollet demonstrated that electricity could be transmitted instantaneously over great distances suggesting that communications could be sent by electricity much faster than a human messenger could carry them.

With the connivance of the Abbot of the Grand Convent of the Carthusians in Paris he assembled 200 monks in a long snaking line with each monk holding the ends of eight metre long wires to form a chain about one mile long. Without warning he connected a Leyden Jar to the ends of the line giving the unsuspecting monks a powerful electric shock and noted with satisfaction that all the monks started swearing and contorting, reacting simultaneously to the shock. A second demonstration was performed at Versailles for King Louis XV, this time by sending current through a chain of 180 Royal Guards since by now the monks were less than cooperative. The King was both impressed and amused as the soldiers all jumped simultaneously when the circuit was completed.

1746 English mathematician and scientist, Benjamin Robins, constructed a whirling arm apparatus to conduct experiments in aerodynamics. He attached a horizontal arm to a vertical pole, which he rotated, causing the arm to spin in a circle. A variety of objects were attached to the end of the rotating arm and spun at high speed through the air. His tests confirmed that the size, the shape and the orientation of the objects had a tremendous effect on air resistance and the drag they experienced. This idea was subsequently picked up and used by others such as Smeaton who used it to derive the aerodynamic lift equation.

1747 - 1753 Fabulously wealthy, eccentric English loner Henry Cavendish discovered the concept of electric potential, that the Inverse Square Law applied to the force between electric charges, that the capacity of a condenser depends on the substance between the plates (the dielectric) and that the potential across a conductor is proportional to the current through it (Ohm's Law).

Charge was provided by Leyden Jars. Potential was "measured" by observing the deflection of the two gold leaves of an electrometer but since no instruments for the measurement of electric current existed at the time, Cavendish simply shocked himself, and estimated the current on the basis of the extent and magnitude of the resulting pain.

Cavendish also analysed the puzzle of the Torpedo fish which seemed to give an electric shock which was not accompanied by a spark. At that time the presence of a spark was considered to be an essential property of electricity. He was the first to make the distinction between, the amount of electricity (its charge), now called Coulombs, and its intensity (its potential difference), now called Volts. He showed that the fish produced the same kind of electricity as produced by an electrostatic generator or stored in a Leyden jar, but the electricity from the fish was high charge with low voltage whereas the electricity from a typical Leyden jar was high voltage with a low charge. This was because the fish's electric charge was generated by a multitude of gelatinous plates, each providing a small charge, connected together is series and parallel combinations as in the cells of a battery, to increase the potential difference and charge capacity respectively. We now know that the fish can generate a voltage of about 250 Volts while the voltage on the Leyden jar could typically be ten times that.

Cavendish recorded all his experiments in notebooks and manuscripts but published very little, principally the results of the chemical experiments which formed the bulk of his work. It was therefore left to Coulomb (1785), Ohm (1827) and Faraday (1837) to rediscover these laws many years afterwards. His papers were discovered over a century later by James Clerk Maxwell who annotated and published them in 1879.

Cavendish's family endowed the Cambridge University Cavendish Laboratories at which many of the world's discoveries in the field of nuclear physics were made.

1747 British physicist Sir William Watson, Bishop of Landaff, ran a wire on insulators across Westminster Bridge over the Thames to a point across the river over 12,000 feet away. Using an earth or ground return through the river. He was able to send a charge sufficiently intense after passing through three people to ignite spirits of wine. Watson was probably the first man to use ground conduction of electricity, though he may not have been aware of its significance at the time. Watson was the first to recognise that a discharge of static electricity is equivalent to an electric current.

1748 Watson uses an electrostatic machine and a vacuum pump to make a glow discharge lamp. His glass vessel was three feet long and three inches in diameter. The first fluorescent light bulb.

1748 To carry out measurements with less risk of electrocution of the experimenter or dragooned assistants Nollet invented one of the first electrometers, the electroscope, which detected the presence of electric charge by using electrostatic attraction and repulsion between two pieces of metallic foil, usually gold leaf, mounted on a conducting rod which is insulated from its surroundings. The first voltmeters.

1748 Swiss mathematician and physicist Leonhard Euler produced this remarkable formula:

eix = cos(x) + i sin(x)

where i = √-1

and e = 2.1828 the base of the natural logarithm, now known as Euler's number.

In the special case where x = π,     then cos(π) = -1 and sin(π) = 0

and Euler's formula reduces to:

ei π = -1

Euler had thus discovered a simple and surprising relationship between three mathematical constants.

Among his many other accomplishments, Euler developed equations for calculating the power and torque developed by hydraulic turbines.

The following are some key developments in hydraulic power technology.

  • Hydropower has been used since ancient times for turning mill wheels in flour mills grinding grain. Its earliest form was the familiar wooden water wheel, often called the Vitruvius wheel after Roman military engineer Vitruvius who in around 15 B.C. first described it in detail. This was a vertical wheel rotating on a horizontal axis perpendicular to the water flow so that the water impinged tangentially to the wheel on flat blades attached to its periphery causing it to turn.

  • The simplest design was the undershot wheel in which the lower part of the wheel dipped into a moving stream and the water impinging on the flat blades or paddles caused the wheel to turn. To turn the horizontal mill stones, the waterwheel had to be coupled to the vertical shaft of the stones via a wooden right-angle gear drive. Undershot wheels are suitable for use in shallow streams but their efficiency is very low, between 5% in the worst case and up to 22% as later calculated by John Smeaton.

    The efficiency was improved in the overshot wheel in which water was fed from above via a chute, or penstock which could control the flow, on to the wheel near the top of its cycle, just past its highest point. Instead of flat blades, the overshot wheel had a series of fixed buckets mounted around its circumference. In action, the weight of the water filled buckets on down side of the wheel compared with the weight of the empty buckets on the up side of the wheel created an unbalanced torque on the wheel causing it to turn. The orientation of the fixed buckets gradually changed as the water wheel rotated through its cycle and the water was discharged as the buckets approached their lowest point and entered their up cycle when the buckets were upside down. The overshot wheel has the double advantage of gravity providing the turning force as well as, to a lesser extent, the momentum of the water. Efficiencies could be as high as 63%.

    Since Roman times a huge variety of water wheels and turbines have been developed to work in a wide range of operating conditions such as high speed low volume, and low speed high volume water flows and intermittent, variable and bi-directional flows as well as systems fully or partially immersed in the water. Practical systems however must be supported by a variety of ancillary control equipment to accommodate fluctuating water supplies and to match them to irregular mechanical or electrical loads and custom power take-off arrangements.

    Water wheels and turbines derive their torque from the change in momentum (mv) of the water flow by changing either the speed, direction, pressure or weight of the flow.

    Impulse turbines obtain their torque by changing the direction of the water flow. They normally operate in air or only partially submerged.

    Reaction turbines develop torque from accelerating water flows between the turbine blades causing pressure differentials. They normally operate fully submerged or encased to contain the water pressure.

    See more about water turbines on the Hydroelectric Power page.

  • 1759 English engineer John Smeaton developed a method of calculating hydraulic efficiencies based on models. He designed several Vitruvian style water wheel installations and was the first to use cast iron wheels and gearing. This was around the start of the industrial revolution and water wheels were beginning to be used for powering machinery and percussion tools but ten years later Watt's steam engine also became available to fulfil that role. Subsequently, most development of hydropower took place in countries with ample, constant and reliable hydro sources such as France and the USA, whereas the development of steam power was pursued more in countries lacking those resources such as the UK.

  • 1767 French inventor Chevalier da Borda analysed the undershot water wheel and proposed that by using a curved blade design it would enable the water to pass through the wheel with minimum turbulence and would therefore reduce losses and hence improve efficiency.

  • 1824 In an attempt to capture the maximum energy from the water wheel French mathematics teacher at the Ecole des Mines, Claude Burdin, expanded on da Borda's idea and published "Hydraulic Turbines" and proposed that the maximum efficiency could be achieved with a water flow parallel to, rather than perpendicular to, the axis of the wheel in a configuration known as axial flow. He pointed out however that using heavily curved blades in an attempt to achieve maximum efficiency would direct the exhaust water flow against the back of the following blade thus slowing it down, while alternatively directing the exhaust downwards allowed the water to leave with comparatively high velocity resulting in less energy being extracted from the water flow. While the factors affecting efficiency were better understood, designing a practical turbine was still a problem.

  • Burdin coined the word "turbine" which he took from the Latin "turbo" meaning a vortex or spinning. The array of blades mounted on the rotating shaft of the turbine is called the "runner".

  • 1827 At the age of 25, French engineer Benoît Fourneyron, a pupil of Burdin, solved many of these efficiency problems with his design for a turbine, capable of producing around 6 horsepower (4.5 kW). It was a horizontal (vertical shaft) radial flow device with the water flowing outwards from the centre using two sets of blades or vanes curved in opposite directions, a fixed set which he called a distributor, also known as wicket gates, which directed the water flow at the optimum angle on to the rotating runner blades. Since the Fourneyron turbine reacts to the pressure on the runner it is classified as a reaction turbine.
  • It was the world's first commercial hydraulic turbine and proved highly successful. Within a few years, hundreds of factories used Fourneyron-style turbines. By 1837, he had produced a 60 hp (45 kW) turbine operating at 2,300 r.p.m. with an efficiency of 80% weighing only 40 pounds. In 1895 Fourneyron-type turbines, designed by Faesch and Piccard of Geneva, were installed in the world's first hydroelectric AC generating station at Niagara Falls coupled to Westinghouse electric generators. See also the Current Wars.

  • 1844 American civil and mechanical engineer Uriah Atherton Boyden made efficiency improvements to early Fourneyron turbines by optimising the passages of the input and exhaust water flows achieving 78% efficiency.

  • 1846 Belfast born James Thomson, elder brother of Lord Kelvin, designed the Vortex inward radial flow reaction turbine which he patented in 1850. Similar to the Francis turbine (see next), water entered around the circumference of a vertical shaft runner and was directed through coupled, moveable (pivoted), curved guide vanes on to curved runner blades to enable optimum performance with different flow rates. It was compact and could work with water heads as low as 3 feet (1 m). His first model turbine, produced in 1847, delivered 0.1 hp (75 W) with an efficiency of 70%. Later models achieved 75% efficiency.

    A Vortex turbine was used in 1878 by William Armstrong to power the world's first hydroelectric power installation at Cragside in the UK.

  • 1849, British born, American James B Francis, chief engineer of the Lowell, Locks and Canals Company, friend of Uriah Boyden, developed the first modern water turbine – the Francis turbine. He made major improvements to Fourneyron's design achieving efficiencies of 90%. Like Thomson's Vortex turbine it was an inward radial flow design, rather than Boyden's outward flow design, but it also included an element of axial flow so that water entered radially and exited axially (now called a mixed flow design). For this it used deeper blades, curved around two axes at right angles to each other. Water was distributed around the circumference of the runner in a spiral casing with reducing diameter to ensure uniform velocity of entry to the blades. Curved stationary guide vanes and shaped rotor vanes ensured that water entered the runner shock and turbulence-free at the correct angle. The runner blades like many reaction turbines were shaped like aerofoils so that the water flow created a greater pressure on one side of the blades than on the other creating a reaction force which caused the runner to rotate. The blades also had a bucket-like curve towards the turbine outlet so that the water impinging on this surface provided an added kick or impulse to the blades before leaving the runner.
  • The Francis turbine operates under a wide range of conditions and remains the most widely used large water turbine in the world today with about 60% of all high power installations.

  • 1851 French engineer Louis Dominique Girard introduced the Girard axial flow impulse turbine. It is comprised of an array of small curved plates arranged in an annular ring around the periphery of a large diameter flat turbine wheel or runner. Water was directed at right angles to the wheel through these moving vanes via a series of fixed, curved vanes in two diametrically opposite quadrants. Very high speeds were possible.

  • 1870s, American inventor Lester Allan Pelton developed the Pelton wheel, an impulse water turbine, which he patented in 1880. Tangential jets of water impinge on pairs of buckets mounted side by side around the circumference of a small wheel. The buckets split the water jet into two equal streams which emerge from opposite sides of the wheel, balancing the side-load forces on the wheel. The curved profile of the buckets ensures smooth water flow maximising the energy capture from the stream. The Pelton turbine is a simple and efficient design which needs only a small water flow and can operate with very high water heads at very high speeds.

  • 1913 Austrian civil engineer Viktor Kaplan developed the Kaplan turbine, a propeller-type turbine with adjustable runner blades as well as adjustable wicket gates directing the water flow for which he received four patents. The machine's variable geometry enabled fine control over the water flow and high efficiencies to be achieved over a wide range of water flows and pressure heads.

See also Steam Turbines.

1750 to 1850 The Industrial Revolution

In the period from around 1750 to around 1850 a series of technical innovations took place in Britain, each one with the simple aim of solving a particular problem or of doing things more efficiently, each one creating yet more opportunities for innovation. The way forward was shown by the development of rudimentary machines to improve productivity by mechanising manual work. The advent of the steam engine raised the potential of this mechanisation to a much greater level. The following were some key developments:

  • (1701) Jethro Tull's seed drill, an early example of mechanisation revolutionised British agriculture.
  • (1709) Abraham Darby's mass production of cast and wrought iron provided the essential materials for building industrial tools and machines.
  • (1712) Thomas Newcomen invented the first practical steam engine which was first used for pumping water out of mines, but with further developments became the workhorse of the industrial revolution.
  • (1733) John Kay's hand operated flying shuttle brought mechanisation to the weaving industry.
  • (1759) Josiah Wedgwood founded his pottery factory. He used mass production techniques coupled with scientific method to determine precise controls on the composition of the glazes, the temperatures of the kilns and the glazing process to produce high quality ceramics. (A typical example of the possibilities of mechanised production of ceramic products. Not unique to Wedgwood). Wedgwood was instrumental in commissioning and funding the Trent and Mersey Canal which secured supplies for his potteries. He was also a pioneer in marketing and advertising, one of the first to open showrooms to display his products and to make skilful use of royal patronage to promote and sell them.
  • (1761) James Brindley extended the British canal system creating a national network facilitating the easier and more economical movement of goods.
  • (1764) James Hargreaves' spinning jenny, powered by hand, brought further mechanisation to the textile industry
  • (1765) Matthew Boulton introduced the factory system to the metalworking industry and provided social security for his employees.
  • (1769) James Watt greatly improved the efficiency of steam engines improving the economic viability of steam power.
  • (1771) Richard Arkwright developed much larger machine driven spinning frames which he installed at Cromford Mill where he pioneered the factory system of production in the spinning industry.
  • (1777-1779) Thomas Pritchard designed, and Abraham Darby III built the World's first iron bridge at Coalbrookdale in Shropshire.
  • (1779) Samuel Crompton invented the spinning mule which could produce a wide range of high quality fine yarns.
  • (1783) Henry Cort improved the processes of steelmaking and forging by means of puddling and rolling mills, reducing the cost of steel and increasing its potential applications.
  • (1786) Matthew Boulton applied steam power to coining machines to manufacture coins for the mint. (A typical example of the possibilities of mechanised production of metal parts. Not unique to Boulton)
  • (1794) Eli Whitney in the USA invented the cotton gin which revolutionised the processing of raw cotton.
  • (1797) Henry Maudslay and James Nasmyth developed precision machine tools while Eli Whitney pioneered manufacturing using interchangeable parts.
  • (1825) George Stephenson opened the world's first public railway initiating a rapid improvement in the country's transport infrastructure.
  • (1827) Benoît Fourneyron developed the first practical water turbine enabling exploitation of low cost water resources, where available, for industrial mechanisation.
  • (1851) Joseph Whitworth introduced new standards of accuracy and precision engineering enabling mass production methods and interchageable parts.
  • (1853) George Cayley published the theory of flight and launched the first manned glider.
  • (1855) Henry Bessemer introduced mass production to steelmaking, lowering steel's cost and increasing its strength, dramatically increasing its use.

Taken together these innovations had a profound and unprecedented affect on society and social, economic and cultural conditions.

Though not fully exploited at the time, several important discoveries were also made towards the end of the period, which laid the ground work for a second wave of innovation based on electrical communications, electric power, computers and household appliances. These were;

What were the results of all of this innovation?

Production methods were mechanised reducing costs and the steam engine enabled factories to use very large machines to achieve even greater levels of mechanisation reducing costs even further. The new transport infrastructure created by the canals and later by the railways made it cheaper and easier to access lower cost supplies of raw materials as well as giving access to new markets for the products produced by the factories. Manufacturing activities which had previously not been economically viable suddenly became possible. New employment opportunities were created with jobs that previously didn't exist such as engineers, draughtsmen, machine builders, tool makers, managers, book keepers and salesmen and with these jobs came the possibility of social mobility. Overall, incomes rose and were more regular and secure. The cost of manufactured goods was reduced creating more demand as well as employment opportunities. More manufactured goods were available and there was a sustained increase in the economic well being of the country.

But there were consequences of these developments. Cottage industries could not compete with mechanised factories and went out of business. The demand for craftsmen, proud of their skills and workmanship, was replaced by the demand for unskilled factory workers to operate machines and to assemble the products. The result was that there was a movement of the rural population towards the towns where living conditions were often unhealthy and far from ideal.

Although conditions in the towns were sometimes grim, the romantic view that industrialisation was a catastrophe and that rural life before these changes took place was idyllic, is unrealistic. The reality of previous rural life was also less than ideal. It was a society of subsistence agriculture ruled by an elite, landed aristocracy. It may have been a more healthy environment in the country but in the seventeenth century, before the industrial revolution, average life expectancy was only 37 years with 18% of infants dying in their first year and 31% of newborns dying before the age of fifteen.

People still lived in poverty. They still used child labour. Incomes were very low and irregular or uncertain, the population was generally illiterate and subject to the demands of landlords who were not necessarily any more benevolent than future factory owners and there were fewer opportunities for personal development and social mobility to escape from this poverty.

Unfortunately many people still write about "The Causes of the Industrial Revolution" as if it was a calamity. A more apt title would replace the word "Causes" with the word "Enablers" to recognise the positive aspects of the changes in the nation's economic welfare which it brought about.

The Industrial Revolution marked the end of feudalism and the beginning of social mobility.

How did this great transformation come about?

The industrial revolution is characterised by the development of an industrial economy resulting from the ever increasing flow of innovative practical products based on the application of new technologies, mechanised production methods and the availability of mechanical power to make it happen. But for these new ideas to flourish, they had to fall on fertile ground and these conditions were found in Britain in the second half of the eighteenth century and the first half of the nineteenth century.

  • The previous two hundred years had seen the flowering of the Scientific Revolution when great thinkers, no longer hampered by censorship of new ideas by the church, provided a theoretical basis for the way things worked. Amongst others, Newton provided the Laws of Motion and Calculus, Boyle and Charles provided the Gas Laws and Hooke provided the Law of Elasticity.
  • Improved methods of time and temperature measurement were also available enabling more accurate scientific experiments to be performed.
  • The country had six universities, founded before 1600, carrying out scientific research and teaching. (Oxford, Cambridge, St Andrews, Glasgow, Aberdeen, Edinburgh)
  • Scientific societies such as the Royal Society (founded 1660), the Lunar Society of Birmingham (dating from 1765) and the Royal Institution (founded 1799), encouraged the sharing and dissemination of ideas.
  • Towards the end of the eighteenth century and during the first half of the nineteenth century, Literary and Philosophical Societies were founded in many British towns and cities, particularly in the north. Known as the "Lit and Phils" they provided the opportunity to discuss intellectual issues of the day and to sponsor cultural activities. Amongst their aims were education and the advancement of science and technology but in the days when there were few forms of public entertainment and recreation, they coincidently provided the opportunity for socialising and networking and so attracted a large membership. Lectures and presentations at the "Lit and Phils" were thus well attended and news about technology and potential investment opportunities reached a wide audience of interested and often influential people. Thoughts evolved from the familiar certainties of the past to the self confident exploration of the potential that the future may bring. Self-help and optimism replaced sufferance of the status quo.
  • The country was being denuded of wood used for fuel but it was self sufficient in energy from coal, which contained more than three times the energy of wood, as well as hydro power. Similarly it had ample supplies of many key raw materials such as iron, lead, copper and tin ores and limestone (used in iron smelting and building materials).
  • The invention of the steam engine gave the country a head start in liberating factories from inefficient manual powered and horse drawn machines or water wheels dependent on unreliable water supplies, enabling improved efficiency and reduced manufacturing costs.
  • Good, stable economic conditions prevailed in the country.
  • Most European countries at the time were ruled by absolute monarchies. Decision making tended to be concentrated in a few hands and high up on their priority list were self preservation and control of their subjects, often accompanied by expansionist territorial aspirations backed by military power.
  • Britain too had international aspirations but by contrast, it had just agreed a "Bill of Rights" in 1689 restricting the power of the monarchy and enhancing the power of parliament. While power was not completely devolved, members of parliament ensured that regional issues got a sympathetic hearing. Priorities such as local transport infrastructure development and the promotion and protection of commerce were higher up the priority list.

  • The development of the road and canal transport infrastructure dramatically reduced the costs of transporting heavy and bulky raw materials such as coal, iron ore and clay for the potteries as well as the distribution of finished goods enabling new resources to be tapped and new markets to be reached. This was accelerated by the advent of the railways whose higher speeds enabled the distribution of fresh foods over greater distances, boosting the agricultural and fishing industries.
  • Certain regions of the country had well organised cottage industries with established industry skills, supplies and trade routes which provided a fertile environment for the introduction of new technologies. A prime example was Lancashire which, because of its damp climate, had a large cotton processing industry with a concentration of textile producers using cotton imported from qualified trading partners. (Originally from India, but progressively from the West Indies and the American colonies.)
  • The rule of law prevailed with contract law and patent law providing legal protection to business and to inventors.
  • The British Empire facilitated extensive international trade networks providing access to foodstuffs and raw materials, mainly cotton, and a ready market for manufactured goods.
  • Profit flows from trade with the colonies accumulated in Britain creating a capital surplus which was available to be invested in factories, machinery, canals and railways. Similarly this influx of wealth created a new demand for manufactured goods for use in the home.
  • The British government encouraged international trade and protected it with a strong global naval presence.
  • Joint stock companies were able to provide funding enabling longer term or large projects to be undertaken.
  • The country had a tradition of free market capitalism supported by parliament and a stock exchange (The Royal Exchange opened by Queen Elizabeth I in 1571) to enable the trading of shares.
  • Insurance was available to underwrite risks. (Insurance deals were traded in Lloyd's Coffee House in London from 1688, initially, mainly for maritime risks)
  • Towards the end of the period, Building Societies were established enabling people to purchase their own property and Hire Purchase Contracts were introduced in support of the sales of sewing machines enabling the set up of small family businesses, both of which in their small way helped to bring about the beginnings of social mobility and the possibility for more people to realise their full potential.

The industrial revolution started in Britain but it was quickly followed in Western Europe, then North America, followed by Japan and eventually the rest of the world (or at least most of it).

1750 Nollet demonstrated the astonishing efficiency of electrostatic spraying, an idea which was not put to practical use until it was rediscovered by Ransburg in 1941.

1750 English physicist John Michell describes magnetic induction, the production of magnetic properties in unmagnetised iron or other ferromagnetic material when it is brought close to a magnet. He discovered that the two poles of a magnet are of equal strength and that they obey the inverse-square law for magnetic attraction in "A Treatise on Artificial Magnets".

1752 German astronomer Tobias Mayer published the method of determining logitude by means of lunar distances together with associated lunar distance tables. The method used only a sextant and the local times were derived from observations of the position of the Moon relative to fixed celestial objects. See more about lunar distances.

1752 French experimenter Thomas François Dalibard, assisted by retired illiterate old dragoon M. Coiffier, carried out an experiment proposed by Benjamin Franklin. They set up their experiment at Marly la Ville and from a safe distance (in Dalibard's case eighteen miles away) they waited for a storm. They used a long pointed iron rod, placed upright in a wine bottle and insulated from the ground by more glass bottles, to attract a lightning discharge from a thunder cloud. Coiffier subsequently drew electrical sparks from the charged rod to prove Franklin's theory that thunder clouds contain electricity and that it can be conducted down a metal rod.

1752 A man of many talents, Benjamin Franklin one of the leaders of the American Revolution and founding fathers of the USA, journalist, publisher, author, philanthropist, abolitionist, public servant, scientist, diplomat and inventor carried out his famous kite experiments in 1752, one month after Dalibard, and invented the lightning rod.

Franklin proposed a "fluid" theory of electricity and outlined the concepts of positive and negative charges, current flow and conductors coining the language to describe them. Words such as battery (from an array of charged glass plates, and later, a number of Leyden Jars), charge, condenser (capacitor), conductor, plus, minus, positively, negatively, armature, electric shock and electrician all of which we still use today.

Du Fay in 1733 had first described the concept of two types of electric charges, "vitreous" and "resinous". Franklin explained that current flow was the flow of a positive charge towards negative charge to cancel it out. Using the water analogy he named the point of high potential, (from which the water flows) as the positive terminal with the lower potential terminal being negative. Current can also be associated with the flow of positive ions from the positive terminal to the negative terminal, or with the flow of negatively charged electrons from the negative terminal to the positive terminal. Nowadays we tend (lazily) to associate current flow exclusively with electron flow, overlooking the equally valid positive ion flow, which leads to the confusion and the incorrect charge that Franklin got it wrong by defining the current flow in the opposite direction from which electrons flow.

The purpose of Franklin's kite experiment was to confirm that lightning was another manifestation of electricity. Legend has it that he flew a kite into a thunder cloud to pick up an electric discharge from the cloud. The electric charge was then conducted down the wet kite string to which a key had been attached near the ground and that sparks were emitted from the key which were used to charge a Leyden jar, thus proving that an electric charge came from the clouds.

Whilst it may be heresy to suggest that Franklin did not actually carry out the kite experiment for which he is famous, there are no reliable witnesses to this event and it is a fact that nobody, including Franklin, has yet been able to duplicate this experiment in the manner he described, and few have been willing to try. One who did was Professor Georg W Richmann, a Swedish physicist working in St Petersburg, who was killed in the attempt on 6 August 1753. He was the first known victim of high voltage experiments in the history of physics. Benjamin Franklin was lucky not to win this honour.

1752 Johann Georg Sulzer notices a tingling sensation when he puts two dissimilar metals, just touching each other, on either side of his tongue. It became known later as the battery tongue test: - the saliva acting as the electrolyte carrying the current between the two metallic electrodes.

1753 A proposal is submitted in an anonymous letter to the Scotsman Magazine signed "C.M.", generally attributed to Scottish surgeon Charles Morrison, for 'An Expeditious Method of Conveying Intelligence'. It described an electrostatic telegraph system using 26 insulated wires to conduct separate charges from a Leyden Jar causing movements in small pieces of paper on which each letter of the alphabet is written.

1757 French botanist Michel Adanson proposed that the discharge from the Senegalese (electric) catfish could be compared with the discharge from a Leyden jar. The ability of certain torpedo fish or sting rays to inflict electric shocks had been known since antiquity however Adanson's theory was new. It was later proved by British administrator and M.P., John Walsh, secretary to Clive of India, who in 1772 managed to draw a spark from an electric eel. It is quite possible that news of Walsh's experiment influenced Galvani to begin his own experiments with frogs.

See also Cavendish's explanation of the reason why a shock could be delivered without an associated spark.

1759 German mathematician Franz Maria Ulrich Theodosius Aepinus published his book, An Attempt at a Theory of Electricity and Magnetism. The first work to apply mathematics to the theory of electricity and magnetism, it explained most of the then known phenomena.

In 1789 Aepinus also made the first variable capacitor which he used to investigate the properties of dielectrics. It had flat plates which could be moved apart and different materials could be inserted between them. Volta also laid claim to the invention of this device and to giving it the name of "capacitor".

1759 English civil engineer, John Smeaton constructed a whirling arm device for investigating the aerodynamic properties of windmills and windmill vanes. It was based on an earlier design by Benjamin Robins and had the same functions as a modern wind tunnel but instead, it consisted of a vertical shaft supporting a rotating arm on which to mount models of windmill vanes which could be made to pass at high speed in a circular path through the still air to determine their relative efficiency. (See diagram of Smeaton's Whirling Arm) At the same time the blades could be rotated by means of a falling weight attached by a cable to a pulley on the windmill shaft. It was used to investigate the effects of camber and angle of attack of the blades.

Using the apparatus, Smeaton determined that the force L on a plate or blade (or aerodynamic lift in the case of wings) is given by:



k is the drag in pounds weight of a 1-square-foot (0.093 m2) plate at 1 mph, known as the Smeaton coefficient

V is is the velocity of the air over the plate in miles per hour

A is the Area of the plate in square feet

CL is the magnitude of the lift relative to the drag of a plate of the same area, known as the lift coefficient

This relationship is known as the lift equation and was used by the Wright brothers in the design of their wings and propellers, though from their wind tunnel experiments they determined a more accurate value for the coefficient k.

Smeaton also used hydraulic models and similar techniques to calculate the efficiencies of water wheels.

He is more well known for the many bridges, canals, harbours and lighthouses that he built. He coined the term "civil engineers" and in 1771 founded the Society of Civil Engineers the forerunner of the Institution of Civil Engineers.

1761 Scottish chemist and physicist Joseph Black working at Glasgow University, discovered that ice absorbs heat without changing temperature when melting and similarly the temperature of boiling water does not change as heat is added to create steam. Between 1759 and 1763 he evolved the theory of latent heat for a heat flow that results in no change of temperature, that is, for the heat flows which accompany phase transitions such as boiling or freezing. He also showed that different substances have different specific heats, the amount of heat per unit mass required to raise its temperature by one degree Celsius.

James Watt was his pupil and assistant.

1761 Self taught, English engineer, James Brindley son of a farmer, opened the Bridgewater Canal which he had designed and built for Francis Egerton the third Duke of Bridgewater to carry coal from his coalmine at Worsely to market in Manchester, ten miles away. Transporting coal by canal boat rather than by pack horse reduced its cost by 50%. The Bridgewater Canal was the first British canal not to follow an existing water course. Instead he chose a more level route by following the contours of the land to simplify construction, avoiding embankments and tunnels as well as the need for the traditional, time-wasting locks. It did however require the construction of an aqueduct at an elevation of 39 feet (13 M) to carry it over the River Irwell, a feature which was unique at the time. The sight of a barge floating high up in the air became one of the first tourist attractions of the Industrial Revolution.

Brindley went on to build another 300 miles of canals. His Bridgewater canal marked the beginning of Britain's golden era of canal building from 1760 to 1830 during which the country's new inland waterway system linked up the otherwise isolated local canals serving the country's major cities into a national network, greatly improving the nation's transport infrastructure.

Before the canal system was built, the transport of bulky goods was prohibitively expensive. They were either sent by sea or overland by pack horse. This meant that users had to be located close to their source of supply or to the docks. Factories depending on steam engines had to be located near to coal mines. But canals changed all that. One canal boat, operated by one man and a horse, could carry as much as a hundred pack horses. Transport by canals cut the costs for industry and provided economic justification for new ventures which previously may not have been viable. Canals were the Motorways of the eighteenth century.

An practical example of the economic benefits of canals was the saving the pottery industry centred on Stoke on Trent. The potteries were originally located there because of the availability of suitable clay and the coal to fire it, but in the 1760s when supplies of local clay were becoming exhausted and markets demanded pottery made with finer clay from other sources, Brindley's Trent and Mersey Canal, opened in 1777, enabled the potters to bring in clay from Dorset, Devon and Cornwall by canal from the seaport rather than to move their business to other locations which may have had the clay but not the coal.

The Trent and Mersey canal necessitated the construction of the Harecastle Tunnel which was 1.64 miles (2633 m) long. It took seven years to construct and when it was completed in 1777 it was more than twice the length of any other tunnel in the world at that time. It was however only 9 feet (2.74 m) wide since it did not have a towpath so that boats had to be "legged" through it by men lying on their backs and "walking" on the roof taking 2 to 3 hours to pass through the tunnel. It was also too narrow to take boats going in both directions so boats had to be grouped and one way system allowed the direction of travel to be changed after each group had passed through. Some enterprising local men offered their service as "leggers" to help speed the boats through.

Brindley died before the canal was completed.

To relieve congestion a second, wider tunnel with a towpath, parallel Brindley's tunnel was commissioned fifty years later. It was slightly longer at 1.66 miles (2675 m) and was built by Thomas Telford. Taking just three years to complete, it was opened in 1827.

The advent of George Stephenson's faster rail transportation brought this golden era to an end.

1764 After the introduction of the flying shuttle which improved the productivity of the weaving industry, the demand for cotton yarn outstripped supply, and the cottage industry producing it, one thread at a time, on traditional spinning wheels could not keep up. In the 1760s several inventors developed machines to mechanise this process.

The first was James Hargreaves of Blackburn, Lancashire who in 1764 invented a multi-spool spinning frame which dramatically reduced the labour content of the work. It was called the spinning jenny ("jenny" derived form "engine"), a machine for spinning, drawing and twisting cotton. It consisted eight spindles driven by a single large handwheel which turned all the spindles. Cotton was drawn from eight separate rovings, long thin bundles of cotton fibre, lightly clasped between two horizontal bars then wound onto the spindles. The spindles were mounted on a moveable carriage which allowed the roving to be stretched as it was pulled away from the clasping bars, imparting a twist to the cotton. He sold several machines but kept his activities secret at first. However the selling price of yarn fell as the production increased while at the same time the employment of local spinners was reduced culminating in his house being attacked and his machines smashed. As a result Hargreaves moved to Nottingham in 1768 where he eventually patented his machine in 1770.

An improved spinning machine, called a spinning frame was invented in 1767 by John Kay a clockmaker from Warrington, Lancashire (No relation to John Kay of Bury) who made improvements to Hargreaves design. Instead of the simple clasp used by Hargreaves to stretch the cotton fibre roving, the roving was passed between three sets of rollers, each set rotating faster than the previous one, progressively reducing the thickness of the roving and increasing its length before a strengthening twist was added to the yarn by a separate mechanism. This produced a much finer and stronger cotton yarn. The spinning frame was also called a water frame when it was powered by a water wheel.

At the time Kay was employed by Richard Arkwright, of Preston, Lancashire, who controversially patented Kay's machine in 1769 under his own name without telling Kay. This resulted in a scandal and caused a protracted patent dispute which involved yet another inventor of a spinning machine, Thomas Highs, of Leigh, Lancashire, who had worked with both Arkwright and Kay who were both familiar with his work. Highs had invented several devices for processing wool and cotton but didn't have the finance to develop his ideas and like Hargreaves, he had worked in secret on his spinning machine which he claimed to have patented in 1769. All the protagonists eventually lost out in the legal proceedings as the jury found against Arkwright but no rights were ever transferred to Highs or Kay.

As the technology of the day advanced, the available power to turn the spindles was increased, evolving from the machine operator himself, to horses, then water wheels and finally to steam engines (now electric motors). This enabled much larger spinning frames carrying over 100 spindles to be constructed, greatly increasing the productivity.

Arkwright was more of a businessman, rather than an inventor. In 1771, he built the world's first water-powered textile mill at Cromford in Derbyshire where he installed production equipment driven by water power in a highly a disciplined factory with workers operating machines in 13 hour shifts with little free time, replacing the local cottage industries where whole families, including their children, developed specialist skills working together at home on traditional crafts and trades. The factory work by comparison was unskilled with the work divided into short repetitive tasks and the employees, in both situations, were mostly illiterate since this was before the advent of universal education in Britain. Most of the employees were women and children, some as young as seven, though this was later increased to ten years old. It sounds horrific, but for his times, Arkwright was an enlightened employer, building houses for his employees and providing the children six hours of education per week so they could take on tasks such as record keeping. His Cromford Mill was the start of the factory system which was quickly copied by others and became a hallmark of the Industrial Revolution.

1765 Matthew Boulton who traded in ornamental metalware such as buttons, buckles and watch chains which were made in small workshops in and around Birmingham, opened the Soho Manufactory at Soho near Birmingham to bring all his business activities together under one roof, under his own ownership and control. Previously the goods were manufactured either in Boulton's own workshops or in the workshops of local independent artisans of which there were many in the Birmingham area.

The Soho Manufactory was a three-story building which housed a collection of small specialist workshops carrying out a range of metalworking process such stamping, cutting, bending and finishing as well as showrooms, design offices, stores, and accommodation for the employees.

Boulton was a benevolent employer. Instead of subcontracting work to other workshops in town, he employed the same skilled craftsmen who had worked in the workshops which he had displaced. Working conditions were good, employment was secure and he paid them well. Labour saving jigs and tools were used to improve productivity as well as the quality of the goods produced, designs were rationalised to achieve economies of scale by using interchangeable or common components. In this way Boulton was able to take on high volume production of items such as coins for the mint as well as fine, high quality products such as jewellery, silverware and plated goods.

He refused to employ young children as in some other industries and later introduced a very early social insurance scheme, funded by workers' contributions of 1/60th of their wages, which paid benefits of up to 80% of wages to staff who were sick or injured.

At its height the factory employed a thousand people in what was the largest and most impressive factory in the world becoming Birmingham's foremost tourist attraction.

Boulton's manufactory established the factory system in the metalworking industry, mirroring changes being made in the textile industry. Another step in the Industrial Revolution.

In 1769 Matthew Boulton also provided the financial backing and the manufacturing capability for the commercialisation of Watt's Steam engine and his Soho plant became the world's first factory to be powered by steam.

1765 A group of prominent figures in the British Midlands, including industrialists, natural philosophers and intellectuals, set up an informal learned society later called the Lunar Society because it met during the full moon to take advantage of the lighter evenings for travelling home after meetings. Members included Matthew Boulton, James Watt, physician and inventor Erasmus Darwin, grandfather of Charles Darwin discoverer of the Theory of Evolution, Josiah Wedgwood and Joseph Priestley. Benjamin Franklin also attended a meeting of the society while visiting Birmingham and kept in touch with members.

1766 Swiss physicist, geologist and early Alpine explorer Horace Benedict de Saussure invents the first true electrometer for measuring electric potential by means of attraction or repulsion of charged bodies. It consisted of two pith balls suspended by separate strings inside an inverted glass jar with a printed scale so that the distance or angle between the balls could be measured. It was de Saussure who discovered the distance between the balls was not linearly related to the amount of charge.

1766 Hydrogen discovered by Henry Cavendish by the action of dilute acids on metals.

1767 English clergyman, philosopher and social reformer Joseph Priestley at the age of 34 made his first foray into the world of science with the publication of a two-volume History of Electricity in which he argued that the history of science was important since it could show how human intelligence discovers and directs the forces of nature. The previous year in London he had met Benjamin Franklin who introduced him to the wonders of electricity and they became lifelong friends. Priestley's first discovery, also in 1767, was that carbon conducts electricity.

Though he had no scientific training, Priestley is however better known as a chemist. He isolated Carbon dioxide, which he called "fixed air", and in a paper published in 1772, he showed that a pleasant drink could be made by dissolving the gas in water. Thus was born carbonated (soda) water, the basis of the modern soft drinks industry.

He was a great experimenter discovering Nitrous oxide (laughing gas) and several other chemical compounds and unaware of the work of Scheele in 1774 he independently discovered Oxygen. Priestley was no theorist however and he passed on his results to the French chemist Lavoisier who repeated the experiments taking meticulous measurements in search of underlying patterns and laws governing the chemical reactions.

Experimenting with growing plants in an atmosphere of Carbon dioxide, Priestley observed that the plants consumed the Carbon dioxide and produced Oxygen, identifying the process of plant respiration and photosynthesis. This was the first connection between chemistry and biology.

As a reformer, Priestley was a strong supporter of the 1776 American and the 1789 French Revolutions. This brought him into conflict with conservatives and in 1791 angry mobs burnt down his house and his church destroying many of his manuscripts. The intimidation continued until 1794 when the aristocratic Lavoisier, on the opposite side of the revolutionary fence from Priestley, was executed by French revolutionaries. A few weeks later Priestley emigrated to America to escape persecution spending the rest of his life there.

1769 The introduction of Watt's Steam Engine was a key event in the Industrial Revolution.

James Watt, a Scottish instrument maker working at the University of Glasgow in 1763 was given the job of repairing a model of Newcomen's 1712 steam engine. He noted how inefficient it was and between 1763 and 1775 he developed several improvements to the design. The most important of these was the introduction of a separate, cold, chamber for condensing the steam which avoided the need to heat and cool the main cylinder which could be kept hot while the steam was condensed in the cold condensation chamber. (See diagram of Watt's Steam Engine)

As in Newcomen's engine, steam introduced under the piston drove it to the top of its stroke at which point the steam was shut off, but the atmospheric power stroke was different. When the piston reached the top of its stroke a valve at the lower part of the cylinder opened releasing the steam into the cold chamber where it condensed, reducing the pressure under the piston which was pushed down by atmospheric pressure on the top of the piston. The use of the separate condenser reduced the heat losses in every cycle and led to a dramatic improvement in the fuel efficiency and speed of the engine and was the basis of Watt's patent in 1769.

Watt's original engine, like Newcomen's, generated most of its mechanical power, that is its atmospheric power, on the downstroke but not on the upstroke and this intermittent power delivery was not suitable for producing smooth, continuous rotary motion. To overcome this drawback, Watt developed a second innovation which was to introduce steam on top of the piston at the top of its stroke as well as below the piston at the bottom of its stroke. This second steam supply pushed the piston down with the steam being exhausted from above the piston into the cold chamber at the end of the down stroke thus creating a double-acting engine with the steam pushing and the vacuum pulling the pistons on both the up and down strokes. A double benefit of this system was that it also improved the efficiency still more. This idea was later developed by Trevithick and others for use in high pressure, horizontal engines.

(See Double Acting Piston).

Watt initially had difficulty in both manufacturing and commercialising his engine but this problem was solved when he entered into partnership in 1769 with Matthew Boulton, a Birmingham manufacturing entrepreneur. Watt had sought help from Boulton to produce the precision components for his steam engine and discovered a willing partner since Boulton's production had often been interrupted by the unreliable water supply to the water wheel powering his Soho factory. The Boulton and Watt company they founded was able to fund the further development of Watt's engines and to manufacture them with improved precision at Boulton's Soho plant. Their engines used only 20% to 25% of the coal used by the Newcomen engines to generate the same power and Boulton was instrumental in securing a patent for the steam condenser which meant that any user of the condenser technology had to pay substantial monthly royalties to the company and this was rigidly enforced. Boulton's Soho plant became the world's first factory with machines powered by a steam engine.

In 1788, Watt invented the centrifugal or flyball governor to provide speed control for his steam engines. An early example of an automatic control system. See diagram of Watt's Flyball Centrifugal Governor.

See more examples of Early Control Systems.

The steam engine was quite literally the driving force behind the Industrial Revolution, freeing people from back breaking work, providing prodigious mechanical power to drive factories and machines enabling a myriad of applications as well as powering the railways thus facilitating trade and travel. The prime movers used for driving the first electricity generating plants by Schuckert, Edison and Ferranti starting in 1878 were also powered by large reciprocating steam engines based on James Watt's technology. The result was that Watt is commonly credited as the father or inventor of the steam engine and with bringing about the birth of and exploitation of this technology but there were many other contributors.

The following are some of the other key technologies and inventions associated with the development of the steam engine and its applications.

1770 French military engineer, Nicolas-Joseph Cugnot built his "fardier à vapeur", a three wheeled, steam driven military tractor, the world's first self propelled road vehicle, based on a smaller model he had produced the previous year. It was a mechanised version of the massive two-wheeled horse-drawn dray or wagon, known in France as a "fardier", used for transporting very heavy military artillery equipment.The boiler and driving mechanism were mounted on a single front wheel at the front of the vehicle replacing the horses. (See picture of Cugnot's Steam Carriage).

The engine used two vertically mounted single acting pistons, acting directly over the wheel, one on each side, with the piston rods connected to a rocking bar, pivoted at the centre, which allowed the piston movements to be synchronised in opposite directions. High pressure steam was applied alternately to the pistons so that the power stroke pushing one piston down caused the opposite piston to move back up ready to start its power stroke. Mounted on the driving axle were two disks one on each side of the single driving wheel, each disk with a ratchet or notches around its circumference. Power was transferred to alternate sides of the wheel by means of the piston rods with pawls which engaged on the ratchets on the down stroke to turn the wheel and slid over the ratchets on the up stroke while the drive was transferred to the disk on the opposite side of the wheel. This arrangement is considered to be one of the early successful devices for converting reciprocating motion into rotary motion. It was also the fore-runner of the freewheel mechanism.

The driving wheel and engine assembly were articulated to the rest of the cart and steering was by means of a lever (tiller steering) which turned the whole driving assembly including the boiler. The vehicle weighed in at over 2 tons and was designed to carry a load of 4 tons at a speed of 2.5 miles per hour. The massive boiler overhung the front of the wheel and made the vehicle somewhat unstable and, since there was no provision for carrying water or fuel, the vehicle needed to stop every ten to fifteen minutes to replenish the water and fuel and relight the boiler fire to maintain the steam pressure.

Cugnot was ahead of his time. Trials in 1771 by the French Army showed up the vehicle's limited boiler performance and difficulties in traversing rough terrain and climbing steep hills and rather than developing the invention, they abandoned the experiment. In 1772 Cugnot was awarded a pension by King Louis XV for his work but this was withdrawn with the start of the French revolution in 1789, and he went into exile in Brussels, where he lived in poverty until he was invited back to France by Napoleon Bonaparte shortly before he died in 1804. His fardier was kept at the military Arsenal until 1800 when it was transferred to the Conservatoire National des Arts et Métiers where it remains on display to this day.

See more about Steam Engines


1771 The world's first machine powered factory began operations in Cromford, Derbyshire. English inventor Richard Arkwright pioneered large scale manufacturing using a water wheel to replace manual labour used to power the spinning frames in his cotton mill.

1771 German-Swedish pharmaceutical chemist, Carl Wilhelm Scheele discovered Oxygen and two years later Chlorine. A prolific experimenter he is also credited with the discovery of the gases Hydrogen fluoride, Silicon fluoride, Hydrogen sulfide, Hydrogen cyanide. In addition he isolated and characterised glycerol, lactose, and ten of the most familiar organic acids including tartaric acid, citric acid, lactic acid and uric acid.

He was also the first to report the action of light on silver salts which became the basis of photography for over 180 years.

He received very little formal education and lived a simple life in a small town so his many achievements received little publicity. One result of this comparative obscurity is that others independently retraced his paths and were later credited with the discoveries he had already made, Priestley for Oxygen in 1774 and Davy for Chlorine in 1810.

Scheele was found dead in his laboratory at the age of 43, his death probably caused by exposure to the many poisons with which he worked. It was not unknown for scientists of his day to taste the chemicals with which they were working.

1774 An electrostatic telegraph is demonstrated in Geneva, Switzerland by Frenchman George Louis LeSage. He built a device composed of 24 wires each contained in a glass tube to insulate the wires from each other. At the end of each wire was a pith ball which was repelled when a current was initiated on that particular wire. Each wire stood for a different letter of the alphabet. When a particular pith ball moved, it represented the transmission of the corresponding letter. Intelligible messages were transmitted over short distances and LeSage's system is considered to be the first serious attempt at making an electrical telegraph.

1775 Like many experimenters of his time Alessandro Volta constructed his own Perpetual Electrophorus (that which carries off electricity) to provide a regular source of electricity for his experiments. It was crude and consisted of a resin plate on which was rubbed cat's fur or a fox tail and another insulated metal plate for picking up the charge.

1775 In response to the demands of the armaments industry the nascent steam power industry English engineer John Wilkinson made one of the first precision machine tools, a cylinder boring machine. His machine secured for him the largest share in the profitable business of supplying cannons in the American War of Independence. Wilkinson is reputed to be Britain's first industrialist to become a millionaire.

1775 Richard Ketley, the landlord of Birmingham's Golden Cross Inn, founded the first Building Society. It was a mutual financial institution owned by its members, originally offering them savings and mortgage lending services. Members of Ketley's society paid a monthly subscription to a central pool of funds which was used to finance the building of houses for members, which in turn acted as collateral to attract further funding to the society, enabling further construction. The idea quickly caught on and building societies were soon established in many cities of the UK. More recently, building societies have expanded into the provision of banking and related financial services to their members.

1779 The world's first iron bridge, built across the River Severn Gorge at Coalbrookdale in Shropshire, was opened. It was designed by Thomas Farnolls Pritchard a local architect from Shrewsbury with a span of a 100 feet (30 m) and was built by the iron maker Abraham Darby III, grandson of Abraham Darby, and is still in use as a pedestrian bridge today. The bridge is a surprisingly graceful design, build from cast iron, but since there was no experience in using cast iron, or any other metal, as a structural material the design used techniques based on the more familiar carpentry using slender, custom designed castings in compression, connected together using mortise and tenon and blind dovetail joints.

The bridge was an engineering marvel in its day. See photograph and details of the Coalbrookdale Ironbridge.

Shares were issued in 1775 to raise the £3,200 estimated cost of the bridge, but Darby found it difficult to find investors and had to give a personal guarantee to cover any costs incurred in excess of this estimate. He was awarded the contract to build the bridge and to supply the iron work from his Coalbrookdale plant and construction was eventually started in 1777 but the actual cost of building the bridge turned out to be £6,000 and resulted in Darby being in debt for the rest of his life.

1779 English inventor, Samuel Crompton invented the spinning mule so called because it is a hybrid which combined the moving carriage of Hargreaves' spinning jenny with the rollers of Arkwright's water frame in the same way that a mule is the product of cross-breeding a female horse with a male donkey. The spinning mule was faster and provided better control over the spinning process and could produce several different types of yarn. It was first used to spin cotton, then other fibres enabling the production of fine textiles.

1780 English inventor James Pickard patented the crank and flywheel to convert reciprocating motion of Newcomen's engine to rotary motion. He offered the patent rights for his device to Boulton and Watt in return for the rights to use Watt's patent for the separate condenser. Watt refused and instead designed a sun and planet gear to circumvent Pickard's patent. Once Pickard's patent expired, Boulton and Watt adopted the crank drive in their engines. The Sun and planet gear was actually designed in 1781 by William Murdoch, an employee of Boulton and Watt, but it was patented in Watt's name.

The sun and planet gear mechanism used two spur gears and was much more complex then the crank mechanism. In this application, the sun gear was fixed to the axle or output shaft and did not rotate about the axle, rather it rotated with the axle. The planet gear also does not rotate on its axis but was fixed to the end of the connecting rod. The reciprocating motion of piston causes the end of the connecting rod on which the planet gear wheel is mounted to trace a circular path around the sun gear causing the sun gear, and hence the output shaft to which is attached, to rotate.

See more about Steam Engines


1782 French mathematician Pierre-Simon Laplace, building on earlier work by Swiss mathematician Leonhard Euler, develops a mathematical operation now called the Laplace Transform as a tool for solving linear differential equations. The most significant advantage is that differentiation and integration become multiplication and division, respectively. This is similar to the way that logarithms change an operation of multiplication of numbers into the simpler addition of their logarithms. By applying Laplace's integral transform to each individual term in differential equations, the terms can be rewritten in terms of a new variable "s" and the equations are converted into polynomial equations which are much easier to solve by simple algebra. The solutions to the original problems are retrieved by applying the Inverse Laplace Transform.

This technique simplifies the analysis control systems and analogue circuits which are characterised by time varying differential equations. Laplace's method thus transforms differential equations in the time domain into algebraic equations in the s-domain.

Between 1799 and 1825 Laplace published in five volumes "Traité de Mécanique Céleste", Celestial Mechanics, a description of the workings of solar system based on mathematics rather than on astronomical tables. In it, he translated and expanded the geometrical study of solar mechanics used by Newton to one based on calculus.

A copy of the work was presented to Napoleon who is reported to have asked why there was no mention of God in the study, to which Laplace is alleged to have replied "Je n'avais pas besoin de cette hypothèse-là". ("I had no need of that hypothesis.").

Laplace also developed the foundations of probability theory which he published in 1812 as "Théorie Analytique des Probabilités". Prior to that, probability theory was solely concerned with developing a mathematical analysis of games of chance as exemplified by Pascal. Laplace applied the theory to the analysis of many practical problems in the social, medical, and juridical fields as well as in the physical sciences including mortality, actuarial mathematics, insurance risks, the theory of errors, statistical mechanics and the drawing of statistical inferences.

In 1799 Laplace was appointed by Napoleon as Minister of the Interior but he was removed after only six weeks "because he brought the spirit of the infinitely small into the government".

He later provided the explanation of the anomaly between Newton's theoretical calculation of the speed of sound and the speeds actually measured.

1783 Henry Cort, owner of a forge in Portsmouth supplying iron products to the British Navy, invented and patented a grooved rolling mill for producing wrought iron bars and rods replacing the ancient method of hammering the bloom produced by the bloomery furnace. This reduced the processing time by over 90% and produced a much cheaper and better quality product.

In 1784 Cort also patented the reverberatory furnace and puddling, a new method of converting cast pig iron into low carbon content wrought iron to improve its quality and tensile strength. (The term "reverberation" was used at the time to describe "rebounding" or "reflecting", NOT "vibrating"). The reverberatory furnace was like a very large oven containing a coal fire which was isolated from a separate hearth containing the pig iron charge which was in turn contained in a "puddle" in the base of the hearth. The hot gases from the fire were directed over the top of the puddle heating it directly and also by reflected heat from the roof over the hearth. In this way poor quality fuel could be used without the risk of contaminating the iron. It was a bit like a modern fan assisted oven used to cook a bowl of soup, with the oven door being opened from time to time to stir the soup, except on a much greater scale.

The puddle of molten pig iron was stirred manually with long rods by "puddlers" to promote oxidation or burning of the remaining carbon in the iron by the oxygen in the hot air to form the wrought iron and CO2 which was released. After the metal cooled and solidified, it was worked with a forge hammer and could be rolled into sheets, bars or rails. This was the method used to produce the wrought iron used in the first ironclad warships. It was also used for the small scale production of low-carbon steels for swords, knives and weapons.

Cort's two inventions reduced the costs and increased the supply of better quality steel with fewer inclusions and a more homogeneous grain structure enabling its potential use in more widespread and new applications.

See also Iron and Steel Making

1784 Cavendish demonstrated that water is produced when Hydrogen burns in air, thus proving that water is a compound of two gases and not an element and overturning over two thousand years of conventional wisdom.

1784 King Louis XVI of France set up a Royal Commission to evaluate the claims by German healer and specialist in diseases of the wealthy, Franz Anton Mesmer who had achieved international notoriety with his theory animal magnetism and its supposed therapeutic powers. Members of the committee included Benjamin Franklin, Antoine Lavoisier and the physician Joseph-Ignace Guillotin, inventor of the Guillotine which was later used to remove the heads of both Lavoisier and the King. Mesmer had claimed extraordinary powers to cure patients of various ailments by using magnets. He also claimed to be able to magnetise virtually anything including paper, wood, leather, water, even the patients themselves and that he himself was a source of animal magnetism, a magnetic personality. His clients were mainly aristocratic women many of whom reported pleasurable experiences as Mesmer moved his hands around their bodies to align the flow of magnetic fluid while they were in a trance. Mesmer was a patron of the composer Wolfgang Amadeus Mozart who included a scene in which Mesmer's magnets were used to revive victims of poisoning in the opera "Cosi fan tutte". The committee however concluded that all Mesmer's observed effects could be attributed to the power of suggestion and he was denounced as a fraud. He did however keep his head (the French revolution was still four years away) and his name lives on as hypnotists mesmerise their subjects.

Guillotin by the way was not a revolutionary. As a physician he merely proposed the guillotine as a more humane method of execution rather than hacking away with a sword.

1785 French military engineer and physicist, Charles-Augustin de Coulomb published the correct quantitative description of the force between electrical charges, the Inverse Square Law, which he verified using a sensitive torsion balance which he had invented in 1777. He showed that the electrical charge is on the surface of the charged body. Coulomb's Law was the first quantitative law in the history of electricity.

Coulomb also founded the science of friction.

The unit of charge is named the Coulomb in his honour.

1786 Luigi Galvani professor of anatomy at Bologna Academy of Science in Italy discovered that two dissimilar metals applied to the leg of a dead frog would make it twitch although he believed that the source of the electricity was in the frog. He was quite possibly influenced in his conclusions by the knowledge of Walsh's experiments with electric fish. He found copper and zinc to be very effective in making the muscles twitch. Could it be animal electricity?.

Galvani, a religious man, believed without question that the electricity was a God given property of the animal and that electrical fluid (electricity) was the "spark of life". On the other hand, his friend Volta more of a showman, influenced by "the enlightenment" and "rational thought" questioned religious dogma and believed that the electricity was man made and came from the metals. For many years a debate raged until it was eventually resolved by Volta's invention of the Voltaic pile. In the meantime Galvani lost his job for refusing to swear allegiance to Napoleon's Cisalpine Republic whereas Volta attempted to accommodate Napoleon and prospered under his rule. Sadly Galvani died in poverty in 1798 without knowing the outcome of the debate.

Galvani's experiments with frogs were repeated on a human specimen in 1803 by his nephew Giovani Aldini at the Royal College of Physicians in London, this time with a battery. He used the corpse of George Forster a convicted murderer, who had just been hanged, to demonstrate the phenomenon called Galvinism. He touched a pair of conducting rods, linked to a large voltaic pile, to various parts of Forster's body causing it to have spasms. When one rod was placed at the top of the spine and the other inserted into the rectum, the whole body convulsed and appeared to sit upright giving the illusion that electricity had the power of resurrection.

It is claimed that Aldini's demonstration was the inspiration for Mary Shelley's 1818 novel "Frankenstein" about a scientist who uses electricity to bring an inanimate body to life with disastrous consequences.

1787 Experiments by French physicist and chemist Jacques Charles (later continued by Joseph Louis Gay-Lussac) revealed that:

  • All gases expand or contract at the same rate with changes in temperature provided the pressure is unchanged.
  • The pressure of a fixed mass and fixed volume of a gas is directly proportional to the gas's temperature. Discovered by Gay Lussac in 1802, the effect (law) is now named after him.
  • The change in volume amounts to 1/273 of the original volume at 0°C for each Celsius degree the temperature is changed.

This work provided the inspiration for Kelvin's subsequent theories on thermodynamics.

Charles' Law and Gay Lussac's Law (1802) together with Boyle's Law (1662) and Avogadro's Law (1811) are known collectively as the Gas Laws.

Combining these laws into one relationship we get the Ideal Gas Law:

pV = nRT


p is the pressure

V is the volume

n is the number of moles associated with the volume

R is the universal gas constant

T is the temperature in degrees Kelvin

Note that P*V has the dimensions of Force*Distance and thus represents a measure of the energy in the system and the relationship implies that the energy in the system is proportional to the temperature and, for a given temperature and a given quantity of gas, the energy is constant no matter how the pressure and volume vary.

In his spare time, Charles was an enthusiastic balloonist making several ascents and improving ballooning equipment.

1787 John Fitch a skilled metalworker and American patriot, after being imprisoned by the British in the Revolutionary war, turned his energy to harnessing steam power. Early steam engines were too big and heavy to be used in practical road vehicles, however this restriction did not apply to large marine vessels which were big enough to accommodate them. Fitch built a 45 foot (13.7 M) steamboat propelled by six paddles on either side like an Indian canoe, following up in 1788 with a 60 foot (18 M) paddle wheeler with stern paddles which moved like ducks' feet. In 1790 he launched an even larger boat, with improved paddle wheels more like modern designs, which operated a regular passengers service on the Delaware river but with few passengers it operated at a loss and his financial backers pulled out. He obtained a French patent for his invention in 1795 but attempts to build a business in Europe also failed.

Undue credit for the invention of the steamboat is often given to Robert Fulton who repeated Fitch's work twenty years later, building and successfully operating steamboats on the Hudson River.

See more about Steam Engines


1789 French chemist Antoine Laurent Lavoisier considered to be the founder of modern chemical science, published Traité Élémentaire de Chimie or "Elementary Treatise of Chemistry", the first modern chemistry textbook. In it he presented a unified view of new theories of chemistry and a clear statement of the Law of Conservation of Mass, which he had established in 1772, that is; "In a chemical reaction, matter is neither created nor destroyed".

In addition, he defined elements as substances which could not be broken down further and listed all known elements at the time including oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulphur. As intended, it did for chemistry what Newton's Principia had done for physics one hundred years earlier.

Lavoisier was the first to apply rigorous scientific method to chemistry. He carried out his experiments on chemical reactions with meticulous precision devising closed systems to ensure that all the products of the reactions were measured and accounted for. He thus demolished the wild ideas of the alchemists as well as the Greek concept of four elements, earth, air, fire and water which had been accepted for over 2000 years.

Lavoisier had a wide range of interests and a prodigious appetite for work and funded his experiments from his part time job as a tax collector. He was aided in his scientific endeavours by his wife Marie-Anne Pierrette Paulze, whom he had married when she was only thirteen years old. The couple were at the centre of a Parisian social life, but in 1794 Lavoisier's tax collecting activities fell foul of France's revolutionary mob and he was Guillotined during the Reign of Terror. An appeal to spare his life was cut short by the judge with the words "The Republic has no need of scientists".

Afterwards the French mathematician Joseph-Louis Lagrange said "It took them only an instant to cut off that head, and a hundred years may not produce another like it".

See also Lavoisier's relationship with Rumford

1790 The first patent laws established un the USA by a group led by Thomas Jefferson. Until US Independence, when Intellectual Property Rights were protected by the American Constitution, the King of England officially owned the intellectual property created by the colonists. Patents had however been issued by the colonial governments and were protected by British law.

The first US patent was granted to Samuel Hopkins of Vermont for a new method of making Potash.

1791 German chemist and mathematician Jeremias Benjamin Richter attempted to prove that chemistry could be explained by mathematical relationships. He showed that such a relationship applied when acids and bases neutralize to produce salts they do so in fixed proportions. Thus he was the first to establish the basis of quantitative chemical analysis which he named stoichiometry. He died of tuberculosis at the age of 45.

1791 English mining engineer John Barber patented a gas turbine engine. His patent, "A Specification of an Engine for using Inflammable Air for the purposes of procuring Motion and facilitating Metallurgical Operations.....and any other Motion that may be required.", outlined the operating principle and thermodynamic cycle of the engine which contained all the essential features of the modern gas turbine. The fuel used was coal gas. Fuel and air were compressed by two separate reciprocating piston pumps, chain driven from the turbine shaft, and then fed into a combustion chamber where the fuel was burned. The expanding combustion gases were then directed through a nozzle onto an impulse turbine wheel driving the output shaft.

Performance was unfortunately limited by the materials technology of the day and losses in the compression stage which reduced the available output power. Barber had a solution to alleviate these problems. He geared a water pump to the output shaft which injected a small stream of cold water into the hot combustion gases to cool the combustion chamber and the impulse wheel. This had the dual benefit in that the resulting steam increased the density of the jet impinging on the turbine wheel and thus increased the power output.

He also envisaged using the output jet from the engine to power a boat through water.

1792 Scottish engineer and inventor William Murdoch employed by Boulton and Watt to supervise their pumping engines in Cornwall was the first to make practical use of coal gas. By heating coal in a closed iron retort with a hollow pipe attached he produced a steady stream of coal gas for lighting his house.

Coal gas was one of the byproducts of pyrolysis or the destructive distillation of coal was already used to produce coke which was used in metallurgical processes to extract metals from their ores. At first the public were not interested in Murdoch's application due to health and safety fears and his employers discouraged him from patenting the idea so he left the company in 1797 to exploit it himself. When others showed interest in commercialising coal gas Boulton and Watt realised their mistake and Murdoch was invited back the following year. Boulton and Watt subsequently became major players in the gas business selling integrated illumination systems with their own self contained gas generators. Coal gas lighting was eventually patented in 1804 by German inventor Friedrich Albrecht Winzer (Frederick Albert Winsor) who pioneered the installation in Britain of public gas lighting and gas distribution systems fed from large central gas works.

The production of coke and coal gas left huge residues of coal tar which were initially regarded as mostly waste. It was another 50 years before Perkin showed how considerable value could be extracted from this waste.

1794 American law graduate and inventor Eli Whitney patented the cotton gin ("gin" derived form "engine") which automated the process of separating cottonseed from raw cotton fibres. It was about 50 times faster than the previous method of processing the cotton by hand and revolutionised cotton production in the United States, work which had formerly been done by slaves. His cotton engine consisted of a box in which was mounted a revolving cylinder with spiked teeth, or wire hooks, which pulled the cotton fibre through small slotted openings thus separating the seeds from the lint. A separate rotating brush, operated from the main drum via a belt and pulleys, removed the loose fibrous cotton lint from the projecting spikes or hooks. Early devices were powered by a hand crank but these were soon replaced by larger horse-drawn or water powered machines.

Paradoxically, the introduction of the cotton gin as a labour saving device did not reduce the demand for slave labour. Because cotton could be produced much more cheaply, the demand increased, more cotton was planted and cotton replaced tobacco and indigo as cash crops so that many more slaves were required to grow the cotton and harvest the fields. Some people claim that by increasing the demand for slave labour, the introduction of the cotton gin was one of the causes of the American Civil War (1861-1865).

Despite the success of the cotton gin, it was quickly copied many times over and Whitney spent much of his money on legal battles over patent infringements.

In 1798 Whitney also pioneered the use of interchangeable parts in the production of muskets which proved to be more commercially successful.

1795 The hydraulic press used for lifting heavy weights or for the presses used in metal forming was patented by English engineer Joseph Bramah. The principle on which it depends was first outlined by Pascal 150 years earlier but not turned into practical products.

Bramah also invented a "burglar proof" lock, which remained unpicked for sixty-seven years and examples are still in use today. The secret of the lock was the precision to which it was made.

1797 Young Prussian noble Alexander von Humboldt published a book outlining his theories about Galvanic electricity and his experiments to support them. He believed that the electricity came from the muscle and was intensified by the electrodes and he carried out experiments on plants and animals to prove it. He also carried out numerous experiments on himself to gather more data using a Leyden jar to inflict severe shocks on his body until it was badly lacerated and scarred. He was mortified three years later when his theories were proved completely wrong by Volta and turned his attention instead to geology, botany and exploration in all of which he found international fame but no fortune.

1797 English engineer Henry Maudslay introduced the precision screw-cutting lathe. Although lathes had been in use from before 3000 B.C. when the Egyptians used the bow lathe for wood turning, Maudslay's lathe was the first true ancestor of the modern machine tools industry.

Maudslay began his career in 1789 as a blacksmith, making machinery for Joseph Bramah, but he progressed to the more precision work required for Bramah's hydraulic and lock making systems when he opened his own business. His first major contract was to make the manufacturing equipment used in Mark Isambard Brunel's block making plant.

He recognised the importance of having an accurate reference plane for marking out, for inspection and for setting out tooling and assemblies to be used as a baseline for all measurements of the work piece. He introduced and championed the use of a solid high precision surface plate, usually made of cast iron for this purpose. He deivised the method of creating these extremely flat surfaces and introduced the use of engineer's blue to aid in this process. The process needs three sets of plates worked together to achieve the necessary degree of flatness. A thin coating of engineer's blue, slightly more sticky than marking blue, is applied to one of the plates and the plate is then rubbed against a second plate. Imperfections are indicated in the areas where the blue has been rubbed off one plate and transferred to the other. Originally these imperfections were corrected by grinding off the high spots but this was superceded by scraping. This process is repeated several times with all three plates until the plates are flat. The third plate is necessary to avoid creating matching pairs of concave and convex plates.

Engineer's blue is also used more generally to identify any high spots or contact between mating pieces. Marking blue, slightly thinner, is used for marking out surfaces in preparation for scribing or drilling.

Maudslay raised the standards of precision, fits, finishes and metrology and invented the first bench micrometer capable of measuring to one ten thousandth of an inch (0.0001 in ≈ 3 µm)which he called the "Lord Chancellor" because it resolved disputes about the accuracy of workmanship in his factory.

His pupils included Scottish engineer James Nasmyth who designed and made heavy machine tools, including the shaper and the steam hammer, for the ship building and railway industries, English engineer Joseph Whitworth who introduced the Whitworth Standard for screw threads and designed the Whitworth rifle and Richard Roberts, inventor of the first practical power loom, the self-acting spinning mule and various machine tools including gear cutting machines. See also Whitney - next.

1798 In an age when mechanical devices were individually made and laboriously fitted by hand, American engineer Eli Whitney pioneered the concept of interchangeable parts in the USA, using precision manufacturing made possible by more accurate machine tools just becoming available. Prior to that, if a part failed, a replacement part had to be made and fitted individually creating major problems and losses in battlefield conditions. Whitney's methods also reduced the skill levels needed to manufacture and assemble the parts enabling him to take on a contract to supply 10,000 muskets in two years to the US government. Whitney also built a rudimentary milling machine in 1818 for use in firearms manufacturing, but the universal milling machine as we would recognise it today was invented by American engineer Joseph Rogers Brown in 1862. Brown's machine was able to cut the flutes in twist drills. See also Whitworth's method of making twist drills which it replaced.

In 1794 Whitney also invented the cotton gin which revolutionised the processing of raw cotton.

1799 Count Rumford, man of science, inventor, administrator, philanthropist, self publicist and scoundrel, born Benjamin Thompson in the USA, founded The Royal Institution in London to promote and disseminate the new found knowledge of the industrial revolution. Its first director was a well connected, glamorous young Cornish chemist, Humphry Davy. Davy was a great showman, but did not consider "common mechanics" worthy of his brilliance, so the Institution rapidly evolved to presenting lectures for the wealthy, who paid to attend. In Rumford's original plan, there had been a back door through which the poor could access a balcony to hear the lectures from a distance for free. Davy had it bricked up. The Institution did, however, perform a very valuable function in that it was a subsidised science lab, one of the very few in the world, which enabled scientists of the day, such as Michael Faraday, to make many important discoveries.

Rumford was a colourful character, like fellow American Benjamin Franklin, a man of many talents. Raised in pre-Revolutionary New England, at the age of 19 he married a wealthy 31-year-old widow and he took up spying on the colonies for the British but left for England in 1776 when he was found out, deserting his wife and daughter. At first he worked in the British foreign office as undersecretary for Colonial Affairs and was knighted by George III after a stint in the army fighting on the British side in the American War of Independence. He moved on to Munich where he carried out public and military works for the Elector of Bavaria being rewarded in 1792 with the title Count of the Holy Roman Empire. Among his inventions were the drip coffee pot and thermal underwear.

His interest in field artillery led him to study both the boring and firing of cannons. Out of this work he saw that mechanical power could be converted to heat -- that there was a direct equivalence between thermal energy and mechanical work. Heat was produced by friction in unlimited quantities so long as the work continued. It could therefore not be a fluid called a Caloric flowing in and out of a substance as his adversary, the noted French chemist, Antoine Lavoisier, had proposed, since the fluid would have a finite quantity.

After Lavoisier's death Rumford started a four year affair with his wealthy, young widow, however after a short unhappy marriage they divorced with Rumford remarking that Lavoisier was lucky to have been guillotined. Rumford lived out the rest of his life in Lavoisier's former house in France engaged in scientific studies and it is claimed that he was paid by the French for spying on the British.

1799 English aristocrat, engineer and polymath, George Cayley, one hundred years before the Wright brothers, outlined the concept of the modern aeroplane as a fixed-wing flying machine with separate systems for lift, propulsion, and control. He was the first to understand the underlying principles and to identify the four basic aerodynamic forces of flight, namely weight, lift, drag, and thrust, which act on any flying vehicle.

Unfortunately there would be no suitable power sources available for many years to realise such a design, but he applied his theories to the design of gliders and made the first successful glider to carry a human being.

Throughout time, countless philosophers and experimenters had been fascinated by the flight of birds and the shape of their wings, however Cayley was the first to undertake a methodical study of the shape and cross section of wings and it is to him that we owe the idea of the curved aerofoils used in modern aircraft designs.

His theories and designs were based on models he had tested on a "whirling-arm apparatus" he had built to simulate airflow over the wings and to measure the drag on objects at different speeds and angles of attack. It had the same functions as a modern wind tunnel but instead, it was based on an earlier design by Smeaton which enabled models to be passed at high speed in a circular path through the still air. Balance springs were used to measure the forces on the model.

From his researches, he showed that a curved aerofoil produces significantly more lift than a simple flat plate. He also identified the need for aerodynamic controls to maintain stability in flight and was the first to design an elevator and a rudder for that purpose.

Cayley's paper "On Aerial Navigation", published in 1810, was the first scientific work about aviation and the theory of flight and marked the birth of the science of aeronautics.

See more about Aerofoils and Theories of Flight.

Cayley is remembered for his ground breaking work on aerodynamics and aeronautics however he was also a prolific inventor and has been called by some "the English Leonardo" though there are other candidates for this accolade (see Hooke) and some of his sketches for ornithopters and vertical takeoff aircraft are reminiscent of Leonardo's drawings. The following are some of his other activities and inventions.

  • In 1800 he presented to parliament a comprehensive plan he had devised for land reclamation and flood control.
  • His early work between 1804 and 1805 centred on ballistics. He designed artillery shells with fins which imparted a rotating movement of the shell about the direction of travel which in turn increased their range and later he introduced shells with explosive caps which increased their destructive power.
  • In 1807 he published a paper on the Hot Air Engine and started a series of experiments to improve its performance. The ideas were picked up by Robert Stirling who made his own improvements and patented the engine in 1816.
  • Also in 1807 he described a reciprocating engine fuelled by gunpowder. It consisted of two pistons connected in line and connected to one of them was an external tube into which a fixed amount of gunpowder was automatically fed with each cycle. A constantly burning flame at the end of the tube ignited the gunpowder and the gas generated, together with the expansion of the air in the second piston due to the heat of the explosion, forced the pistons to the top of their stroke. The pistons were returned to the start position by means of a stout bowspring. The engine did not produce rotary motion. There is no record of it having been built and the idea was abandoned as being too unreliable.
  • In his quest for a lightweight undercarriage for his gliders, Cayley turned his attention in 1808 to the wheels. For centuries wheels had been made with stout wooden spokes to support the weight of the vehicle exerted through the axle bearing down on the spokes. The spokes themselves had to be strong enough to support this compressive load so that wheels were generally very heavy. Cayley turned the problem on its head. Instead of spokes in compression, he designed a wheel in which the axle was suspended from the rim of the wheel by slender wire spokes in tension. The magnitude of the force was the same but a wire under tension can accommodate much higher forces than a shaft of wood under compression. This lightweight wheel was the forerunner of the modern bicycle wheel. Cayley thus re-invented the wheel.
  • Another of his inventions was the caterpillar track which he patented in 1825 shortly after Stephenson ran his first railway service, now used in tanks and earth moving equipment. It was an attempt to free steam trains from their dependence on the fixed itinerary determined by the railway lines so that they could deviate down untracked roads. He called it the "Universal Railway".
  • He experimented with light, heat and electricity and in 1828 he estimated absolute zero temperature to be -480°F about 11.44°C lower than the 273.15°C confirmed by Kelvin in 1848.
  • Cayley gave a lot of attention to the safety on the new railway systems crisscrossing the country. His first idea, published in 1831, after the first fatal railway accident at the 1829 Rainhill trials when the unfortunate William Huskisson was run over by Stephenson's Rocket, was a "Cow Catcher" though this was never introduced in Britain. At the same time he examined operating procedures and recommended that speed limits and driver training should be introduced. He also proposed the introduction of automatic braking systems and designed a braking system for that purpose. To reduce injuries in case of accidents he designed a compressed air buffer truck to be incorporated into the trains and recommended that passengers should wear seat belts and that the walls of the carriages should be covered with padded cushions (air bags?). In 1841 he also proposed new operating procedures coupled with a method of automatic signalling he designed to ensure that no two trains could ever meet on the same tracks.
  • He also campaigned for the compulsory introduction of self-righting lifeboats following designs by William Wouldhave in 1789 and earlier proposals in 1785 by Lionel Lukin.
  • Following a fire at London's Covent Garden Theatre in 1808 which twenty three firemen were killed, Cayley proposed the design of a new theatre which incorporated many of the features which are included in modern fire regulations such as safety curtains, large outward opening doors, a large reservoir of water and a pumps to direct it onto the fire. His proposal was not accepted and 47 years later its replacement, built in the classical Athenian style, was burnt to the ground.
  • Prompted by a friend who had lost his hand, in 1845 he designed a prosthetic hand with spring movements which enabled it to grip and pick up objects. At the time there were few concessions by the government or society to disabled people and amputees merely had a hook in place of their hand. Cayley's idea was considered too expensive and fell on stony ground.
  • In 1849, Cayley produced a small biplane glider in which a 10 year old boy made a short test flight. It was the world's first "heavier than air flying machine" to carry a human being. He followed up in 1853, at the age of 79, with a full scale glider which carried his reluctant coachman across Brompton Dale in Yorkshire.
  • In his spare time he was also a Member of Parliament, representing Scarborough.

Cayley had strong views that people should not profit in any way from human suffering and did not patent any of the ideas relating to safety or disability.


VOLTA Inventor of the Battery

Alessandro Volta

The man who started it all.

Voltaic Pile - The First Battery

Volta's Pile

Alessandro Volta of the University of Pavia, Italy, describes the principle of the electrochemical battery in a letter to the Royal Society in London. The first device to produce continuous electric current. He had been interested in electrical phenomena since 1763 and in 1775 he had made his own electrophorus for carrying out his experiments. He was a friend of Galvani but disagreed with him about the nature of electricity. Galvani's experiments with frogs had led him to believe that the source of the electricity was the frog, however Volta sought to prove that the electricity came from outside of the frog, in his case from the dissimilar metals used to probe the specimen.

His "Voltaic Pile" was initially presented in 1800 as an "artificial electric organ" to demonstrate that the electricity was independent of the frog. It was constructed from pairs of dissimilar metals zinc and silver separated by a fibrous diaphragm (Cardboard?) moistened with sodium hydroxide or brine and provided the world's first continuous electric current. The pile produced a voltage of between one and two volts. To produce a higher voltages he connected several piles together with metal strips to form a "battery". He was the first to understand the importance of "closing the circuit".

Volta's invention caused great excitement at the time and he gave many demonstrations including drawing sparks from the pile, melting a steel wire (the first fuse?), discharging an electric pistol and decomposing water into its elements. Though little more than a curiosity at first, the ability to deliver electric energy on demand was an important development contributing to the Industrial Revolution.

Napoleon was particularly impressed, insisting on helping with the demonstrations when he was present and showering Volta with honours despite the fact that France and Italy were initially at war with each other. The unit of electric potential was named the Volt in his honour.

After the invention of the battery, Volta was awarded a pension by Napoleon and he began to devote more of his time to politics, holding various public offices. He retired in 1819 and died in 1827 and although the battery was a sensation in scientific circles and giving impetus to an intensification of scientific investigation and discovery throughout the nineteenth century, surprisingly Volta himself never participated in these opportunities.

1800 English scientists, William Nicholson and Anthony Carlisle, experimenting with Volta's chemical battery, accidentally discovered electrolysis, the process in which an electric current produces a chemical reaction, and initiated the science of electrochemistry. (A discovery like many others claimed by Humphry Davy though he did actually do original work at a later date on electrolysis).

This new technique, made possible by the availability of the constant electric current provided by the new found batteries, enabled many compounds to be separated into their constituent elements and led to the discovery and isolation of many previously unknown chemical elements. Electrolysis, "loosening with electricity", thus became widely used by scientific experimenters.

1800 German born, English astronomer, Frederick William Herschel in an experiment to measure the heat content of the various colours in the visible light spectrum, placed a thermometer in the spectral patches of coloured light. He discovered that not only did the temperature rise as he approached the low frequency, red end of the spectrum, but the temperature continued to rise beyond the red colour even though there were no visible light rays there. The conclusion was that the energy spectrum of the Sun's light was wider than that visible to the naked eye. The long wave radiation below the red end of the spectrum was named infra red radiation.

1801 After Herschel's discovery of radiation below the red end of the light spectrum (See above), German physicist, Johann Wilhelm Ritter, explored the short wave region above the violet end of the spectrum. Using the phenomenon discovered by Scheele, that the colourless salt, Silver chloride is turned black by light rays from the violet end of the spectrum, he showed that higher frequency rays from above the violet radiation also caused strong blackening of the silver salt. This higher frequency energy was named ultra violet radiation.

1801 French silk-weaver, Joseph-Marie Jacquard invented an automatic loom using punched cards to control the weaving of the patterns in the fabrics. This was not the earliest implementation of a stored program and the use of punched cards programmed to control a manufacturing process as is often claimed. That honour goes to Bouchon starting in 75 years earlier and improved by Falcon in 1728 and eventually refined by de Vaucanson in 1744. Jacquard presented his invention in Paris in 1804, and was awarded a medal and patent for his design by the French government who consequently claimed the loom to be public property, paying Jacquard a small royalty and a pension. Its introduction caused riots in the streets by workers fearing for their jobs.

Despite the loom's fame, Jacquard's principles of programmed control and automation were not applied to any other manufacturing process for another 145 years when Parsons produced the first numerically controlled machine tools.

1801 Frenchman Nicholas Gautherot observed that when a current from a voltaic battery was sent between two Copper plates immersed in Sulphuric acid, for a short period afterwards the copper plates could drive a current back in the opposite direction. He had inadvertently discovered the rechargeable battery but did not realise its significance. Sixty years later Planté repeated the experiment with Lead plates and the Lead Acid battery was born.

1802 English chemist Dr William Cruikshank designed the first battery capable of mass production. A flooded cell battery constructed from sheets of copper and zinc in a wooden box filled with brine or acid.

Cruikshank also discovered the electrodeposition of copper on the cathodes of copper based electrolytic cells and was able to extract metals from their solutions, the basis modern metal refining and of electroplating, but it was not until 1840 that the commercial potential of the plating process was realised by the Elkingtons.

1802 British chemist William Hyde Wollaston discovered dark lines in the optical spectrum of sunlight which were subsequently investigated in more detail and catalogued by Fraunhofer in 1814.

Wollaston also investigated the optical properties of quartz crystals and discovered that they rotate the plane of polarisation of a linearly polarised light beam travelling along the crystal optic axis. He applied this property in his invention of the Wollaston prism in which he used two crystal prisms mounted back to back to separate randomly polarised or unpolarised light into two orthogonal, linearly polarized beams which exit the prism in diverging directions determined by the wavelength of the light and the angle and length of the prism. Wollaston prisms are used in polarimeters and also in Compact Disc player optics.

Wollaston was also active as a chemist. He discovered the element Palladium in 1803 and Rhodium the following year and in 1816 he invented improvements to the battery. His attempts to invent an electric motor were less successful however bringing him into conflict with Michael Faraday.


1803 Ritter first demonstrated the elements of a rechargeable battery made from layered discs of copper and cardboard soaked in brine. Unfortunately there was no practical way to recharge it other than from a Voltaic Pile and for many years they remained a laboratory curiosity until someone invented a charger. Ritter was one of the first to identify the phenomenon of polarisation in acidic cells. He also repeated Galvani's "frog" experiments with progressively higher voltages on his own body. This was probably the cause of his untimely death at the age of 33.

1803 John Dalton a Quaker school teacher working in Manchester resurrects the Greek Democritus' atomic theory that every element is made up from tiny identical particles called atoms, each with a characteristic mass, which can neither be created or destroyed. Dalton showed that elements combine in definite proportions and developed the first list of atomic weights which he first published in 1803 at the Manchester Literary and Philosophical Society and at greater length in book form in 1808.

In 1801 Dalton also formulated the empirical Law of Partial Pressures, now considered to be one of the Gas laws. It states that in a mixture of ideal gases the total pressure is equal to the sum of the partial pressures of each individual component in a gas mixture. In other words, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. Besides its concentration, the partial pressure of the gas in a gas mixture has a major effect in determining its physical and chemical reaction rates.

For an example of the application of the Law of Partial Pressures see Refrigeration.

1804 The Electric telegraph one of the first attempted applications of the new electric battery technology was proposed by Catalan scientist Francisco Salvá. One wire was used for each letter of the alphabet and each number. The presence of a signal was indicated by a stream of hydrogen bubbles when the telegraph wire was immersed in acid. The system had a range of one kilometer.

1804 Mining engineer Richard Trevithick, known as the Cornish Giant, built the Pen-y-Darren steam engine, the first locomotive to run on flanged cast iron rails. It hauled 10 tons of iron and 70 men on 5 wagons from Pen-y-Darren to Abercynon in Wales on the Merthyr Tydfil tramroad, normally used for horse drawn traffic, at a speed of 2.4 mph (3.9 km/h) thus disproving the commonly held theory that using smooth driving wheels on smooth rails would not allow sufficient traction for pulling heavy loads. (See Trevithick's Pen-y-Darren Locomotive)

Trevithick's locomotive incorporated several radical innovations. He did not use the steam engine with a separate condenser recently invented by James Watt, the most efficient technology of the day, partly to circumvent the onerous conditions of the Boulton and Watt patent, but also because Watt's engines were too heavy and bulky for mobile use. Instead, to achieve greater efficiencies in a smaller, lighter engine he used a high pressure system with the power stroke being produced by high pressure steam on the piston rather than atmospheric pressure as in Watt's engine.

Higher pressure systems exposed weaknesses in current boiler designs which Trevithick overcame by using a cylindrical construction which was inherently stronger and could withstand much higher pressures and this became the pattern for all subsequent steam engines.

He did however use one of Watt's other innovations, the double acting piston, in which a sliding valve coupled to the piston enabled the steam to be applied alternately to each surface of the piston providing a power stroke in both the forward and back motions of the piston. (See Double Acting Piston).

To improve combustion efficiency he replaced the conventional method of producing steam in which an external flame was used to heat the water in a separate kettle or boiler, by using instead, a return flue boiler in which a U shaped, internal fire tube flue passed through the water boiler and bent back on itself to increase the surface area heating the water. Efficiency was further improved by directing the exhaust steam from the driving piston up the chimney to increase the air draft through the boiler fire. Known as the "blast pipe", this latter steam release is what gave steam engines their characteristic puffing sound.

Together, these innovations provided a 10 fold increase in efficiency over Watt's engine and all of these ideas were subsequently used by George Stephenson on his Rocket locomotive.

Converting the reciprocating motion of the piston to rotary motion for driving the wheels was however was the Achilles heal of this particular engine being overly complicated. The single horizontal piston was located centrally above the boiler and the linear motion of the piston was transferred through a connecting beam perpendicular to the piston to two connecting rods or cranks, one on either side of the boiler. On one side the crank drove a large flywheel to smooth the motion and on the opposite side of the boiler the crank turned a spur gear mounted on the same shaft as the flywheel. The drive from this input gear was transferred via a large intermediate gear to spur gears mounted on the two drive wheels on the same side of the engine. There was no drive to the two wheels on the opposite side of the vehicle.

Trevithick was a larger than life character, bursting with ingenious ideas but unsuccessful in converting them into profitable business. Between 1811 and 1827 he spent time working on steam engines used in Peruvian silver mines and exploring South America on his way back. After a perilous journey he arrived penniless in Cartagena in Colombia where by amazing coincidence he met Robert Stephenson, whom he had known as a child, who paid his passage home.

See more about Steam Engines


1805 Italian chemist Luigi Valentino Brugnatelli, friend of Volta demonstrated electroplating by coating a silver medal with gold. He made the medal the cathode in a solution of a salt of gold, and used a plate of gold for the anode. Current was supplied by a Voltaic pile. Brugnatelli's work was however rebuffed by Napoleon Bonaparte which discouraged him from continuing his work on electroplating.

The process later became widely used for rust proofing and for providing decorative coatings on cheaper metals. Gold plating is used extensively today in the electronics industry to provide low resistance, hard wearing, corrosion proof connectors.

1807 English physician, physicist, and Egyptologist Thomas Young introduced a measure of the stiffness or elasticity of a material, now called Young's Modulus which relates the deformation of a solid to the force applied. Also called the Modulus of elasticity it can be thought of as the spring constant for solids. Young's modulus is a fundamental property of the material. It enables Hooke's spring constant, and thus the energy stored in the spring to be calculated from a knowledge of the elasticity of the spring material.

Young was the first to assign the term kinetic energy to the quantity ½MV2 and to define work done, as force X distance which is also equivalent to energy, an extension to Newton's Laws but surprisingly taking 140 years to emerge. More surprising still is that it was another 44 years before the concept of potential energy was proposed.

He also did valuable work on optical theory and in 1801 he devised the Double Slit Interference experiment which verified the wave nature of light. He directed a light source through a slit in a plate and observed a broad strip of light on a screen a short distance behind the plate. Repeating the experiment with two parallel slits, the light passing through, and spreading from, the slits and illuminating the screen appeared as a series of bright and dark parallel bands on the screen. The slight difference in the light path lengths to the screen via the two separate slits results in a phase shift between the two emerging light beams which creates constructive and destructive interference between the light waves passing through the different slits when they are recombined. This interference pattern thus confirmed the wave nature of light. See diagram of Young's Double Slit Experiment.

But see also Taylor's demonstration of the Corpuscular Nature of Light.

Young is considered by some to be the last person to know everything there was to know. (Not the only candidate to this fame). He was a child prodigy and had read through the Bible twice by the age of four and was reading and writing Latin at six. By the time he was 14 he had a knowledge of at least five languages, and eventually his repertoire grew to 12. He practiced medicine until the work load clashed with his other interests, and among his many accomplishments he translated the inscriptions on the Rosetta Stone which was they key which enabled hieroglyphics to be deciphered.

1807 Humphry Davy constructed the largest battery ever built at the time, with over 250 cells, and passed a strong electric current through solutions of various compounds suspected of containing undiscovered elements isolating Potassium and Sodium by this electrolytic method, followed in 1808 with the isolation of Calcium, Strontium, Barium, and Magnesium. The following year Davy used his batteries to create an arc lamp.

In 1810 Davy was credited with the isolation of Chlorine, already discovered by Scheele in 1773.

In 1813 Davy wrote to the Royal Society stating that he had identified a new element which he called Iodine, four days after a similar announcement by Gay-Lussac. The element had in fact been isolated in 1811 from the ashes of burnt seaweed by Bernard Courtois, the son of a French saltpetre manufacturer, who had passed samples to Gay-Lussac and Ampère for investigation. Ampère in turn passed a sample to Davy. Although Courtois discovery was not disputed, both Davy and Gay-Lussac claimed credit for identifying the element.

1807 Robert Fulton a prolific American inventor is most remembered for building the Claremont steamboat which successfully plied the Hudson River in 1807 steaming between New York and Albany in 32 hours with an average speed of 5 miles per hour. He had earlier built a steamboat based on John Fitch's design which operated on the Seine in Paris in 1803. Where Fitch succeeded technically but failed commercially, Fulton made a commercial success of Fitch's technology and is unduly remembered as the inventor of the steamboat.

See Napoleon's judgement of the idea.

See more about Steam Engines


1807 As a result of his studies on heat propagation, French mathematician Baron JeanBaptiste Joseph Fourier presented a paper to the Institut de France on the use of simple sinusoids to represent temperature distributions. The paper also claimed that any continuous periodic signal could be represented as the sum of properly chosen sinusoidal waves.

For the previous fifty years the great mathematicians of the day had sought equations to describe the vibration of a taut string anchored at both ends as well as the related problem of the propagation of sound through an elastic medium. French mathematicians Jean-Baptiste le Rond d'Alembert and Joseph-Louis Lagrange and Swiss Leonhard Euler and Daniel Bernoulli had already proposed combinations of sinusoids to represent these physical phenomena and in Germany, Carl Friedrich Gauss had also been working on similar ways to analyse mechanical oscillations (see below). Whereas their theories applied to particular situations, Fourier's claim was controversial in that it extended the theory to any continuous periodic waveform.

Among the reviewers of Fourier's paper were Lagrange, Adrien-Marie Legendre and Pierre Simon de Laplace, some of history's most famous mathematicians. While Laplace and the other reviewers voted to publish the paper, Lagrange demurred, insisting that signals with abrupt transitions or "corners", such as square waves could not be represented by smooth sinusoids. The Institut de France bowed to the prestige of Lagrange, and rejected Fourier's work. It was only after Lagrange died that the paper was finally published, some 15 years later.

When Fourier's paper was eventually published in 1822, it was restated and expanded as "Theorie Analytique de la Chaleur", the mathematical theory of heat conduction. The study made important breakthroughs in two areas. In the study of heat flow, Fourier showed that the rate of heat transfer is proportional to the temperature gradient, a new concept at the time, now known as Fourier's Law.

Of greater importance however were the mathematical techniques Fourier developed to calculate the heat flow in unusually shaped objects. He provided the mathematical proof to support his 1807 claim that any repetitive waveform can be approximated by a series of sine and cosine functions, the coefficients of which we now call the Fourier Series. These coefficients represent the magnitudes of the different frequency components which make up the original signal. When the sine and cosine waves of the appropriate frequencies are multiplied by their corresponding coefficients and then added together, the original signal waveform is exactly reconstructed. Thus complex functions such as differential equations can be converted into simpler trigonometric terms which are easier to handle mathematically by calculus or other methods.

This mathematical technique is known as the Fourier transform and its application to an electrical signal or mechanical wave is analogous to the splitting or "dispersion" of a light beam by a prism into the familiar coloured optical spectrum of the light source. An optical spectrum consists of bands of colour corresponding to the various wavelengths (and hence different frequencies) of light waves emitted by the source. In the same way, applying the Fourier transform to an electrical signal separates it into its spectrum of different frequency components, often called harmonics, which makes it very useful in electrical engineering applications.

Fourier showed that the harmonic content of a square wave can be represented by an infinite series of harmonics approximated by the expression:


f(t) =        1 sin (nωt)    Where ω is the pulse repetition frequency.

           n=1    n

High frequency harmonics are required to construct the sharp pulse transitions of the square wave so that a high bandwidth is required to transmit a pulsed waveform without distortion. In practice, 10 to 15 times the fundamental frequency of the bit rate provides enough bandwidth to transmit a recognisable square wave. Thus to transmit a 1 kHz square wave would require a channel bandwidth of at least 10 kHz.

In electrical engineering applications, the Fourier transform takes a time series representation of a complex waveform and converts it into a frequency spectrum. That is, it transforms a function in the time domain into a series in the frequency domain, thus decomposing a waveform into harmonics of different frequencies, a process which was formerly called harmonic analysis.

The Fourier Transform has wide ranging applications in many branches of science and while many contributed to the field, Fourier is honoured for his insight into the practical usefulness of the mathematical techniques involved.

Fourier led an exciting life. He was a supporter of the Revolution in France but opposed the Reign of Terror which followed bringing him into conflict and danger from both sides. In 1798 he accompanied Napoleon on his invasion of Egypt as scientific advisor but was abandoned there when Nelson destroyed the French fleet in the Battle of the Nile. Back in France he later provoked Napoleon's ire by pledging his loyalty to the king after Napoleon's abdication and the fall of Paris to the European coalition forces in 1814. When Napoleon escaped from Elba in 1815 Fourier once more feared for his life. His fears were unfounded however and, despite his disloyalty, Napoleon awarded him a pension but it was never paid since Napoleon was defeated at Waterloo later that year.

As noted above Fourier was not the only one at the time looking for simple solutions to complex mathematical problems. Gauss was trying to calculate the trajectories of the asteroids Pallas and Juno. He knew that they were complex repetitive functions but he only had sampled data of the locations at particular points in time rather than a continuous time varying function from which to construct a mathematical model of the trajectories. Although this was before Fourier's time, like his contemporaries Gauss was aware that the result should be a series of sinusoids, but deriving a transform from sampled or discrete data, rather than from a time varying mathematical function, involves a huge computational task. Such a transform applied to sampled data is now known as a Discrete Fourier Transform (DFT) and can be considered as a digital tool whereas the general Fourier Transform only applies to continuous functions and can be considered as an analogue tool. In 1805 Gauss derived a mathematical short cut for computing the coefficients of his transform. Although he applied it to a specific, rather than a general case, we would recognise Gauss's short cut today as the Fast Fourier Transform (FFT) even though it owed nothing to Fourier.

1808 Prolific Swedish chemist Jöns Jacob Berzelius working at the University of Uppsala in Sweden formulated the Law of Definite Proportions (discovered by Dalton five years earlier and by Richter twelve years before that) which establishes that the elements of inorganic compounds are bound together in definite proportions by weight. Berzelius developed the system of chemical notation we still use today in which the elements were given simple written labels, such as O for oxygen, or Fe for iron, and proportions were noted with numbers. He accurately determined the relative atomic and molecular masses of over 2000 elements and compounds.

1808 Fearing for his life, French civil and marine engineer, architect and royalist, Mark Isambard Brunel, fled from France in 1793 at the start of the "Reign of Terror" which followed the French Revolution after the execution of King Louis XVI. Settling in New York and taking American citizenship, he became the City's Chief Engineer with friends in high places including Alexander Hamilton, one of the U.S. founding fathers. Hearing from one of Hamilton's guests that the Britain's Royal Navy required 100,000 wooden pulley blocks per year as part of their war effort and were looking for a better method of manufacturing them, Brunel saw it as an opportunity to use his engineering talents in a venture too good to miss. Encouraged by Hamilton who saw Brunel's antipathy towards Napoleon as a way to hamper the French, he left the U.S. for England in 1799 with a letter of introduction from Hamilton to Lord Spencer, the British Navy Minister.

After winning a contract to manufacture 60,000 wooden pulley blocks per year, Brunel designed and set up one of the first ever mass production lines which went live in 1808. Instead of one man making a complete pulley Brunel divided the work into a series of simple, short cycle, repetitive tasks and using 43 custom designed, precision machines from Henry Maudslay to carry out the sequential operations in line. In this way he reduced the labour required to do the work from 110 men to 10. A formula which has become an industry standard.

See also Brunel's Thames Tunnel

1809 At a demonstration at the Royal Institution, Davy amazed the attendees by producing an electric arc between two Carbon electrodes - the first electric light and the first demonstration of the useful application of electricity. It was no longer just a curiosity. The demonstration marked the start of a new era, the era of electricity.

Davy is generally credited with inventing the Carbon arc lamp, however a Russian Vasilli V. Petrov had reported this phenomenon in 1803.

In 1816 Davy claimed the credit for the invention of the miner's safety lamp, named the "Davy lamp" in his honour but it was actually similar to a design already demonstrated in 1815 by self taught railway pioneer George Stephenson. The privileged Davy was incensed that he could be upstaged by working class Stephenson.

According to J. D. Bernal's "Science in History" Davy is quoted as saying "The unequal division of property and of labour, the difference of rank and position amongst mankind, are the sources of power in civilized life, its moving causes, and even its very soul."

See also Davy and the Royal Institution


1811 Italian physicist Amadeo Avogadro discovered the concept of molecules. He hypothesized that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. From this hypothesis it followed that relative molecular weights of any two gases are the same as the ratio of the densities of the two gases under the same conditions of temperature and pressure.

This relationship called Avogadro's Hypothesis or Avogadro's Law, now considered as one of the Gas Laws, can be expressed as:

V1 / n1 = V2 / n2

where V is the volume of the gas and n is the number of molecules it contains.

The concept of a mole is a useful measure of the number of "elementary entities" (usually molecules or atoms, but also ions or electrons) contained in a system. See definition of a mole.

The number of "elementary entities" in one mole has been defined as Avogadro's constant or Avogadro's number. It's value was not determined until 1905 by Einstein in his doctorial dissertation.

Note that Avogadro's Number NA divided by by the atomic mass of an element gives the number of atoms of that element in one gram.

Thus Uranium-235 contains 6.022 X 1023 / 235 = about 2.563 X 1021 atoms per gram.

The basic scheme of atoms and molecules arrived at by Dalton and Avogadro underpins all modern chemistry.

1812 German physician Samuel Thomas von Sömmering increased the range of Salvás (1804) telegraph to three kilometers by using bigger batteries, a method subsequently used with disastrous results on the Transatlantic Telegraph Cable.

1812 Venetian priest and physicist Giuseppe Zamboni developed the first leak proof high voltage "dry" batteries with terminal voltages of over 2000 Volts. They consisted of thousands of small metallic foil discs of tin or an alloy of copper and zinc called "tombacco", separated by paper discs stacked in glass tubes. The technology was not well understood at the time and while Zamboni consciously avoided the use of any conventional corrosive aqueous electrolyte in the cells, hence the name "dry" battery, the electrolyte was actually provided by the humidity in the paper discs and a variety of experimental greasy acidic pulps spread thinly on the foils to minimise polarisation effects. Although the battery voltage was very high, the internal resistance was thousands of megohms so the current drawn from the batteries was about 10-9 amps, limiting the battery's potential applications. One notable application however was a primitive electrostatic clock mechanism in which a pendulum was attracted towards the high voltage terminal of a Zamboni pile by the electrostatic force between the pendulum and the terminal. When the pendulum touched the terminal it acquired the same charge as the terminal and was consequently deflected away from it towards the opposite pole of another similar pile from which, by a similar mechanism it was deflected back again, thus maintaining the oscillation. The current drain or discharge rate of the batteries was so low as to be undetectable with instruments available at the time and it was thought that the pendulum was a "perpetual electromotor". In fact Zamboni primary batteries have been known to last for over 50 years before becoming completely discharged!

1813 French mathematician and physicist Siméon Denis Poisson derived the relationship which relates the electric potential in a static electric field to the charge density which gives rise to it. The resulting electric field is equal to the gradient of the potential. This equation describes the electric fields which drive the flow of charged ions through the electrolyte in a battery.

Poisson published many papers during his lifetime but he is perhaps best remembered for his 1837 paper on the statistical distribution now named after him. The Poisson distribution describes the probability that a random event will occur in a time or space interval under the conditions that the probability of the event occurring is very small, but the number of trials is very large so that the event actually occurs only a small number of times. He used his theory to predict the likelihood of being killed by being kicked by a horse and tested it against French army records over several years of the number of soldiers killed in this way. Apart from analysing accident data, the distribution is fundamental to queuing theory which is used in traffic studies to dimension applications from supermarket checkouts and tollgates to telephone exchanges.

1814 German physicist Joseph von Fraunhofer identified and catalogued a series of 570 dark lines, first noticed by Wollaston in 1802, corresponding to specific wavelengths in the visible light spectrum from cool vapours surrounding the Sun.

In 1859 Kirchhoff and Bunsen began a systematic investigation of these lines and deduced that the dark lines were caused by absorption of radiation by specific elements in the upper layers of the Sun's atmosphere. Comparing these lines with the light spectrum emitted by individual elements on Earth enabled them to identify the elements present in the Sun.

1816 A two wire telegraph system based on high voltage static electricity activating pith balls, using synchronous clockwork dials at each end of the channel to identify the letters, was demonstrated in the UK by Francis Ronalds, an English cheese maker and experimental chemist, and subsequently described in his publication of 1823. Coming only a year after Wellington's victory over Napoleon at Waterloo, it was turned down by the haughty Admiralty, who had just invented semaphore signalling, with the comment "Telegraphs of any kind are now wholly unnecessary". It was an invention before its time and nobody showed any interest. At the time it was however witnessed by the young Charles Wheatstone who was later credited in the UK with the invention of the telegraph.

1816 William Wollaston built the forerunner of the reserve battery. To avoid strong acids eating away the expensive metal plates of his batteries or cells when not in use, he simply hoisted the plates out of the electrolyte, a system copied by many battery makers in the nineteenth century.

1816 Scottish clergyman, Dr. Robert Stirling patented the Stirling Engine a Hot Air external combustion engine first proposed by George Cayley in 1807. Key to the design was an "economiser", now called a regenerator, which improved the thermal efficiency. The first practical engine of this type, it was used in 1818 for pumping water in a quarry. The thermodynamic operating principle, later named the Stirling cycle in his honour, is still the basis of modern Stirling engine applications.

1819 French physicists Pierre Louis Dulong and Alexis Thérèse Petit formulated the law named after them that "The atoms of all simple bodies have exactly the same capacity for heat." In quantitative terms the law is stated as - The specific heat capacity of a crystal (measured in Joules per degree Kelvin per kilogram) depends on the lattice structure and is equal to 3R/M, where R is the gas constant (measured in Joules per degree Kelvin per mole) and M is the molar mass (measured in kilograms per mole). In other words, the dimensionless heat capacity is equal to 3.

Dulong and Petit's Law proved useful in determining atomic weights.

1819 Moses Rogers captain of the passenger ship the SS Savannah converted it from a three masted sailing ship to a paddle steamer by installing a 90 horse power steam engine in it. More a hybrid than a steamship, it was 98 feet long with a displacement of 320 tons. Its fuel storage capacity was very low since the main propulsion was intended to be by the sails with the paddle wheels only coming into use when the wind speed was too low. The paddle wheels were 16 feet (4.9 m) in diameter and unusually, they could be stored on deck when the ship was under sail. A steam ship was such a rare sight that when people saw the ship under steam they thought it was on fire. The captain was unable to pursuade any travellers to risk their lives on the steamer's first Atlantic crossing which consequently took place as an experimental voyage without passengers.

In 1819 it crossed the Atlantic from Savannah to Liverpool in 29 days and 11 hours, entering the record books as the first steam ship to make the transatlantic crossing, but the engine was used for a total of about 80 hours during the journey. The return trip was made under sail in rough weather and took 40 days.

1820 Danish physicist Hans Christian Øersted showed how a wire carrying an electric current can cause a nearby compass needle to move. The first demonstration of the connection between magnetism and electricity and of the existence of a hitherto unknown, non-Newtonian force. Two major scientific discoveries from a simple experiment.

1820 One week after hearing about Øersted's experiment, French physicist and mathematician André-Marie Ampère showed that parallel wires carrying current in the same direction attract eachother, whereas parallel wires carrying current in opposite directions repel eachother.

He also showed that the force of attraction or repulsion is directly proportional to the strength of the current and inversely proportional to the square of the distance between the wires.

He precisely defined the concept of electric potential distinguishing it from electric current. He later went on to develop the relationship between electric currents and magnetic fields.

Ampère's life was not a happy one. Traumatised by his father's execution by the guillotine during the French Revolution, there followed two disastrous marriages, the first one resulting in the early death of his wife. Finally he had to cope with an alcoholic daughter. The epitaph he choose for his gravestone says Tandem Felix ('Happy at last'). The unit of current was named the Ampère in his honour.

1820 French mathematician Jean-Baptiste Biot, together with compatriot Felix Savart , discovered that the intensity of the magnetic field set up by a current flowing through a wire varies inversely with the distance from the wire. This is now known as Biot-Savart's Law and is fundamental to modern electromagnetic theory. They considered magnetism to be a fundamental property rather than taking Ampére's approach which treated magnetism as derived from electric circuits.

1820 Johann Salomo Christoph Schweigger professor of mathematics, chemist and classics scholar at the University of Halle, Germany built the first instrument for measuring the strength and direction of electric current. He named it the "Galvanometer" in honour of Luigi Galvani rather than a "Schweiggermeter"???. Galvani was in fact unaware of the concepts of current flows and magnetic fields.

1820 Dominique François Jean Arago in France demonstrated the first electromagnet, using an electric current to magnetise an iron rod.

1820 American chemist Robert Hare developed high current galvanic batteries by using spiral wound electrodes to increase the surface area of the plates in order to achieve the high current levels used in his combustion experiments. He also used such batteries in 1831 to enable blasting under water.

Hare also developed an apparatus he called the Spiritoscope, designed to detect fraud by Spiritualist mediums, and in the process of testing his machine, he became a Spiritualist convert and eventually became one of the best known Spiritualists in the USA.

1821 Prussian physicist Thomas Johann Seebeck discovered accidentally that a voltage existed between the two ends of a metal bar when one end was cooled and the other heated. This is a thermoelectric effect in which the potential difference depends on the existence of junctions between dissimilar metals (in this case, the bar and the connecting wire used to detect the voltage). Now called the Seebeck effect, it is the basis of the direct conversion of heat into electricity and the thermocouple. See also the Peltier effect discovered 13 years later which is the reverse of the Seebeck effect.

Batteries based on the Seebeck effect were introduced by Clamond in 1874 and NASA in 1961.

1821 The English scientist Michael Faraday was the first to conceive the idea of a magnetic field which he demonstrated with the distribution pattern of iron filings showing lines of force around a magnet. Prior to that, electrical and magnetic forces of attraction and repulsion had been thought to be due to some form of action at a distance.

In 1821 Faraday made the first electric motor. It was a simple model that demonstrated the principles involved. See diagram. Current was passed through a wire that was suspended into a bath of Mercury in the centre of which was a vertical bar magnet. The mercury completed the circuit between the battery and the wire. The current interacting with the magnetic field of the magnet caused the wire to rotate in a circular path around the magnetic pole of the magnet. This was the first time that electrical energy had been transformed into kinetic energy. In 1837 Davenport made the first practical motor but it did not achieve commercial success and for forty years after Faraday's original invention the motor remained a laboratory curiosity with many weird and wonderful designs. Typical examples are those of Barlow (1822) and Jedlik (1828).

This invention was the source of a bitter controversy with Humphry Davy and William Hyde Wollaston, recently President of the Royal Society, who had tried unsuccessfully to make an electric motor. Faraday was unjustly accused of using Wollaston's ideas without acknowledging his contribution. The upshot was that Faraday withdrew from working on electromagnetics for ten years concentrating instead on chemical research.

Consequently it was not until 1831 that Faraday invented a generator or dynamo to drive the motor. Surprisingly nobody else in the intervening ten years thought of it either. Faraday had shown that passing a current through a conductor in a magnetic field would cause the conductor to move through the field but nobody at the time thought of reversing the process and moving the conductor through the field (or conversely moving a magnet through a coil) to create (induce) a current in the conductor.

In an ideal electrical machine, the energy conversion from electrical to mechanical is reversible. Applying a voltage to the terminals of a motor causes the shaft to rotate. Conversely rotating the shaft causes a voltage to appear at the terminals, thus acting as a generator. It was not until 1867 that the idea of a reversible machine occurred to Werner Siemens and practical motor-generators were not realised until 1873 by Gramme and Fontaine.

Faraday, the Father of Electrical Engineering, was the son of a blacksmith. A humble man with no formal education, he started his career as an apprentice bookbinder. Inspired by the texts in the books with which he worked and with tickets given to him by a satisfied customer, he attended lectures in 1812 given by the renowned chemist, Sir Humphry Davy, at the Royal Institution. At each lecture Faraday took copious amounts of notes, which he later wrote up, bound and presented to Davy. As a consequence Faraday was taken on by Davy as an assistant for lower pay than he received in his bookbinding job. During his years with Davy he carried out much original work in chemical research including the isolation new hydrocarbons but despite his achievements he was treated as a servant by Davy's wife and by Davy who became increasingly jealous of Faraday's success. Davy also opposed Faraday's 1824 application for fellow of Royal Society when he himself was president. Davy died prematurely in 1829 at the age of 50, it is said like Scheele, from inhaling many of the gases he discovered or investigated.

Faraday went on to eclipse his mentor discovering electrical induction, inventing the electric motor, the transformer, the generator and the variable capacitor and making major contributions in the fields of chemistry and the theoretical basis of electrical machines, (See Faraday's Law), electrochemistry , magneto-optics and capacitors. His inventions and theories were key developments in the Industrial Revolution, providing the foundations of the modern electrical industry, but Faraday never commercialised any of his ideas concentrating more on teaching. He was perhaps the greatest experimenter of his time and although he lacked mathematical skills, he more than made up for it with his profound intuition and understanding of the underlying scientific principles involved which he was able to convey to others. He used his public lectures to explain and popularise science, a tradition still carried on in his name by the IEE today.

Although he was noted for his many inventions, Faraday never applied for a patent.

In 1864 he was offered the presidency of the Royal Institution which he declined. Not so well known is his relationship with Ada Lovelace who idolised him and pursued him over a period of several months in 1844 writing flattering and suggestive letters to which he replied, however in the end he did not succumb to her charms.

When the British Prime Minister asked of Faraday about a new discovery, "What good is it?", Faraday replied, "What good is a new-born baby?"

Saint Michael? - Among Victorian scientists and experimenters, Faraday is revered for his high moral and ethical standards. A deeply religious man, he overcame adversity to become one of the nineteenth century's greatest scientists and an inspiring teacher commanding admiration and respect, but he was not entirely beyond criticism. In 1844 a massive explosion in the coal mine of the small Durham mining village of Haswell killed 95 men and boys, some as young as 10 years old: - most of the male population of the village. The mine owners would accept no responsibility for the disaster and the coroner refused to allow any independent assessor to enter the mine. Incensed, the local villagers took their grievance all the way to the Prime Minister, Sir Robert Peel. Such was the national concern that Peel dispatched two eminent scientists to investigate, Faraday the "government chemist" and Sir Charles Lyell the "government geologist". Their verdict was "Accidental death" and, pressurised by the coroner, they added "No blame should be attached to anyone". In the days before social security, the consequences of this verdict were destitution for the bereaved families.

Faraday's biographers who mention the Haswell mining disaster usually only recount the story that Faraday conducted the proceedings while seated on a sack which, unknown to him, was filled with gunpowder.

1822 English mathematician Peter Barlow built an electric motor driven by continuous current. It used a solid toothed disc mounted between the poles of a magnet with the teeth dipping into a mercury bath, similar in principle to the Faraday disk. Applying a voltage between the shaft and the mercury caused the disc to rotate, the contact with the moving teeth was provided by the mercury.

1822 Probably Britain's greatest engineer, Isambard Kingdom Brunel was sent to France in 1820 at the age of 14 by his father, Mark Isambard Brunel, to acquire a more thorough academic grounding in engineering and to serve an apprenticeship with master horologist and instrument maker Abraham Louis Breguet. Returning in 1822 the 16 year old took up his first job working in his father's drawing office which at the time was preparing the plans for the Thames Tunnel.

In his lifetime Isambard Brunel designed and built 25 Railways, over 100 bridges and tunnels, 3 ships, 8 docks and a pre-fabricated field hospital.

He thought big. Inspired, rather than deterred, by the seemingly impossible, his projects were audacious in scale and ambition, taking engineering way beyond the boundaries of what conventional wisdom believed to be possible with the technology of the day, setting new limits which were not matched by others for decades. A great all round engineer, he turned his hand to architectural, civil, mechanical and naval projects contributing to every detail of the designs. Nor was he afraid to get his hands dirty, helping out the men working on his projects with their manual work when necessary.

Brunel's aspirations may have had no limits, however there was a price to pay for this ambition. He had a prodigious capacity for work and would often be engaged in a number of major projects at any one time, but the actual fulfillment of his projects was carried out by contractors whom he hired and these contractors were frequently driven beyond their limits.

Though his engineering achievements were truly heroic they were not always accompanied by commercial success for his clients and engineering success was often tarnished by unrealistic expectations, aborted projects, missed deadlines, cost over-runs, accidents and in the worst cases, lives lost, and when things went wrong the contractors usually got the blame.

The following are just some of Brunel's achievements:

The Tunnels

  • 1825 - 1843 Thames Tunnel
  • Working for his father on the Thames Tunnel was Brunel's first job. A very difficult project. Previous attempts by Richard Trevithick and others to tunnel beneath the Thames had failed and subsequent formal investigations had judged such a construction to be impracticable. But Brunel and his father persevered despite enormous difficulties and proved the sceptics wrong. See Thames Tunnel.

    It was an experience which gave the young Isambard the confidence to take on many more "impossible" projects over in his subsequent career.

  • 1836 - 1841 Box Tunnel
  • The route for Brunel's Great Western Railway (See below) was designed to follow the most direct route minimising curves and inclines. This necessitated building a tunnel 1.83 miles (2,937 m) long through Box Hill in Wiltshire. At the time,it was the longest railway tunnel in the world.

    Though easier than the Thames Tunnel, the project was not without its difficulties. To speed the construction, work was carried out simultaneously on six separate isolated tunnel sections beneath the hill. They were essentially closed underground chambers until they were able to link up to the adjacent chambers as the excavation of the tunnel progressed. Access to these chambers for the workmen and for removing the excavated earth and rock was through the ventilation shafts,which were up to 290 feet (88 m) deep. Horses at the surface powered the hoists used for this purpose.

    Working conditions were very hazardous. Blasting through the rock in the underground chambers took place with the workmen present and consumed 1 ton of explosives per week. Illumination was by candle light and much of the work was done with pick and shovel. Water ingress had been underestimated and water often gushed from fissures in the limestone strata and from time to time emergency evacuations of the workmen were necessary.

    The project was completed in 1841, one year late and cost the lives of 100 workers.

The Bridges

Though Brunel designed over 100 bridges for his railway projects he did not follow a standard pattern. When the opportunity, or necessity, arose he came up with some striking and unique designs. The three examples which follow are perhaps his best known. All three are still in use today carrying modern day traffic.

(See pictures of Brunel's Bridges)

  • 1831 - 1864 Clifton Suspension Bridge
  • While convalescing in 1928 from his accident in the Thames Tunnel, Brunel, at the age of 24, submitted a design for his first major project on his own, independent of his father. It was in response to a public tender for a road bridge across the Avon Gorge in Bristol, his home town. Brunel's design was for a suspension bridge with the roadway suspended from chains rather than cables. The main span of 702 ft 3 in (214.05 m) was the longest in its day. In 1931 the results of the tender were announced with Brunel's Clifton Suspension Bridge judged as the winner. Work started immediately but was abandoned in 1843 when Bristol's City Council ran out of funds. After Brunel's death in 1859, work on the bridge was restarted as a memorial to its designer with funds raised by the Institution of Civil Engineers. It was completed in 1864.

  • 1835 - 1838 Maidenhead Railway Bridge
  • The Maidenhead Railway bridge was designed to carry Brunel's Great Western Railway (GWR) over the Thames. As with the Box Tunnel, Brunel's objective was to avoid inclines so that the elevation of the bridge had to be as low as possible above the surrounding fields. At the same time it needed wide spans across the river with high headroom to avoid impeding the river traffic below. Brunel's solution was a brick built bridge with two very wide but at the same time very slender arches of 128 feet (39 m) with a rise of only 24 feet (7 m). At the time it was the widest span for a brick arched bridge and today it still an essential link in the main line carrying high speed trains from London to the West Country.

  • 1848 - 1859 Royal Albert Bridge at Saltash

  • The Royal Albert Bridge is a railway bridge linking Devon with Cornwall spanning the River Tamar at Saltash. Because of the terrain, the railway approaches the bridge from both sides of the river on curved tracks and it was not possible find a simple construction which balanced the horizontal thrust on the bridge piers. Brunel's solution was to use a lenticular truss construction, also known as bowstring girder or tied arch construction, to carry the track bed. Heavy tubular arches in compression formed the top chords of the trusses, and chains in tension formed the bottom chords, balancing the compression forces in the arches. These trusses simply rested on the piers without exerting any horizontal thrust on them. The unique design used two spans of 455 feet (138.7 m) each. Construction started in 1848 and the bridge was opened by Prince Albert in 1859. Like the Maidenhead Bridge it is still carrying mainline rail traffic today.

The Railways

  • 1833 - 1841 Great Western Railway - GWR
  • Despite having no experience in railway construction, in 1833, just four years after the Rainhill Trials had established the viability of public railway systems, at the age of the 27 Brunel was appointed chief engineer for building the Great Western Railway between London and Bristol.

    The estimated price of the route was to be £2.8 million. Government approval was given and construction was started in 1835.

    As was typical of Brunel, he was personally involved in every aspect of the enterprise, from raising the finance to project management and everything in between. He set the highest standards for design and workmanship and took personal charge of every detail of the design, from all the bridges and tunnels along the line, the railway stations at the ends of the line down to the architectural details of their lamp posts and even the contractors' tools.

    Brunel himself surveyed the entire route between London and Bristol, a distance of 118 miles. His target was to minimise inclines and curves so that the trains could run at high speed with increased passenger comfort.

    Responsibility for providing the trains was delegated to Daniel Gooch, an engineer who had trained with Robert Stephenson. For even higher speed and comfort, Brunel specified his trains to run on tracks much wider than the conventional "Stephenson's gauge" of 4 ft 8 1⁄2 in (1,435 mm). He chose to set his tracks 7 ft 0 1⁄4 in (2,140 mm) apart, on what became known as Brunel's "broad gauge". This added significantly to the cost of the bridges, tunnels, embankments and cuttings all along the line and required specially made trains to run on the tracks. This no doubt provided better comfort and speed but it was incompatible with the rest of the rail network making interconnections with the existing railway system difficult. This was one of the first ever standards wars and as has happened many times since, the superior technical system eventually lost out (in 1892) to the inferior system and had to be replaced because the older system had built up a much greater user base. (See The Stockton and Darlington Railway).

    Telegraph signalling using Cooke and Wheatstone's system was installed between Paddington station and West Drayton on 9 April 1839, a distance of 13 miles (21 km). It was the first commercial use of telegraph signalling on the railways.

    Brunel set the standard for railway excellence. When the line was completed in 1841 the alignment was so straight and level that some called the line "Brunel's Billiard Table" and the GWR was affectionately known as "God's Wonderful Railway".

    But the work had cost £6.5 million, more than double the original estimate, and thanks to the problems at the Box Tunnel it was one year late.

High Speed Trains?

  • Brunel's GWR, 118 miles (190 km) long, was completed in 1841, 6 years after approval by parliament, using an army of navvies equipped with only picks and shovels. It used Brunel's unique broad gauge track for which new trains had to be developed and manufactured during the same period.
  • 177 years after the GWR was approved, Britain's new High Speed Train system HS2 connecting London with Manchester and Leeds with 330 miles (531 km) of narrower, standard gauge track was announced by the government in 2012. Using powerful earthmoving equipment, tunneling machines, prefabricated track and bridge sections and automated track laying equipment it is scheduled for completion in 2033, 21 years after initial approval, including time for consultations and further approvals, at a cost of £43 Billion.

The Architecture

The designs for the prestigious railway stations at the termini, and stations in between, of the Great Western Railway are further examples of Brunel's versatility.

The Ships

Brunel's vision extended beyond the shores of Great Britain. He envisaged the Great Western Railway (GWR) as the first link en route to North America with the second link carried by steam-powered iron-hulled ships. Before the GWR was completed he set about fulfilling that dream.

As with all of his projects, his ideas were big. In the case of naval engineering there were good technical reasons justifying his opinions. He was aware that the volume or carrying capacity of a ship is proportional to the cube of its dimensions, whereas the water resistance is proportional to the cross sectional area of the ship below the water line and, to a lesser extent to, the surface area of the ship in the water and these are both proportional to the square of the ship's dimensions. This meant that larger ships would be more efficient and that larger steam powered ships would need comparatively less fuel. This was particularly important for ocean going ships since their range was limited by the amount of fuel they could carry.

There are however practical limits to the size a ship can be, due to the flexing or hogging of the hull as it passes over the waves which affects their seaworthiness. The installation of a heavy steam engine in the ship would tend to make this worse. Wooden-hulled ships are particularly prone to hogging and their length is limited to about 300 feet (100 m) whereas the hull of an iron ship can be made much more rigid and thus less subject to hogging so that much bigger ships are possible. The conclusion was that in order to carry sufficient fuel as well as the cargo across the Atlantic in steam powered ships they would have to be big and preferably iron-hulled.

As ever, Brunel was undaunted by his lack of experience in this new endeavour but went on to design and build three ships that revolutionised naval engineering.

  • 1836 - 1837 SS Great Western
  • Brunel's first ship, the 'Great Western', was the first steamship designed to provide a transatlantic service. It was an oak-hulled, paddle wheel steamer with a displacement of 2300 tons, powered by two Maudslay and Field steam engines with a combined output of 750 horse power driving side-wheel paddles. The hull was reinforced with iron straps to increase its rigidity and it had four masts to carry auxiliary sails. At 236 feet (72 m) long, it was the longest ship in the world and had the capacity to carry128 first class passengers with 20 servants and 60 crew.

    It was launched in 1837 and then sailed to London where it was fitted with the engines. On the return journey to Bristol the following year, under her own steam, fire broke out in the engine room. When Brunel went to investigate, he was descending a ladder down into the engine room when it gave way due to damage from the fire and he fell 20 feet (6 m) to the floor landing face down and unconscious in the water being used to douse the flames. Seriously injured once more, he missed the maiden voyage to New York eight days later. As a result of the fire, 50 passengers cancelled their bookings. In 1837, only 9 years after the first demonstration of practical mobile steam power at the Rainhill Trials, the thought of crossing the Atlantic powered by a noisy, newfangled and possibly unreliable steam engine must have terrified the bravest of souls.

    On 4 April 1838, while the Great Western was being readied for the journey, The Sirius, a smaller ship, with a displacement of 1,995 tons, designed to operate a ferry service between London and Cork in Ireland, was chartered by a rival company, British and American Steam Navigation, and left Cork destined for New York instead of London. Similar to the Great Western but smaller, it was a side-wheel, wooden-hulled steamship, 178 feet 4 inches (54.4 m) long with two masts for auxiliary sails, also built in 1837 (by Robert Menzies & Sons in Scotland) but never intended for crossing the Atlantic. Although it was overloaded with the maximum amount of coal it could carry, it was not enough to complete the journey, and the crew burned the cabin furniture, spare yards which carry the sails and one of the masts in their attempt for the Sirius to be the first ship to cross the Atlantic under its own steam. Sailing ships normally did the journey in 40 days, but the Sirius made the crossing in 18 days, 4 hours and 22 minutes at an average speed of 8.03 knots (14.87 km/h).

    The Great Western embarked on her maiden voyage from Bristol, to New York four days after the Sirius left Cork and arrived in New York with 200 tons of coal still aboard just one day after the Sirius, after a crossing 220 miles longer, making the journey in 15 days 5 hours at an average speed of 8.66 knots (16.04 km/h). The Sirius made only one more round trip to New York, whereas the Great Western made a total of 45 round trips for its owners in the following 8 years before it was sold.

    Note: Neither of these ships was the first steamship to cross the Atlantic. That record was claimed in 1819 by the American steamship the SS Savannah which was tiny by comparison.

  • 1839 - 1843 SS Great Britain
  • Brunel made several proposals for a sister ship to the Great Western. His final proposal in 1839 was for the SS Great Britain, designed to carry 252 passengers (later increased to 730) and 130 crew for a cost of £70,000. It was the first to use a screw propeller to drive an iron-hulled steam ocean going ship. Bigger still than the Great Western, it was the largest ship afloat, 322 ft (98.15 m) long with a displacement 3675 tons powered by engines weighing 240 tons with a rated power of 1,000 H.P. and 5 schooner rigged and 1 square rigged mast to carry auxiliary sails. The final cost was £117,000.

    Launched in 1843 the Great Britain was the first iron ship to cross the Atlantic making the voyage from Liverpool to New York in 1845 in a time of 14 days. Screw propellers had recently been claimed by Ericsson to be more efficient than paddle wheels and the Great Britain was fitted with a six bladed screw propeller with a diameter of 15 feet 6 inches (4.7 m), which was only 5% less efficient than modern day propellers. This enabled her to achieve speeds of 11 to 12 knots (20 to 22 km/h).

  • 1854 - 1858 SS Great Eastern
  • In 1852 Brunel was employed by the Eastern Steam Navigation Company to build another ship. His challenge was to design a ship to carry 4,000 passengers with a crew of 418 around the world without refuelling. (At the time there were no bunkering services to refuel ships en route to Australia). To accomplish this the ship would have to be big. Very big!

    His answer was the Great Eastern. Aided by John Scott-Russell, an experienced naval architect and ship builder, Brunel conceived and built the Great Eastern, an iron ship with a displacement of 32,160 tons, it was 692 ft (211 m) long, only 22 % shorter than the 882 ft 6 in (269.0 m) Titanic which was launched 53 years later in 1911. It was powered by five steam engines with a total output power of 8,000 H.P. (6.0 MW). Four of the engines drove two paddle wheels, each 56 feet (17 m) in diameter, and the fifth powered a four bladed screw propeller with a diameter of 24 feet (7.3 m) which enabled the colossal ship to reach a speed of 14 knots (26 km/h). She also had six masts to carry auxiliary sails. The ship was also the first to be constructed with a double-skinned hull, a safety feature which was decades ahead of industry practice.

    Brunel estimated the cost of building the ship to be £500,000. It ultimately cost double that.

    Its keel was laid down at Millwall on the Thames on 1 May 1854 and construction took just over three years to complete. Because it was so long, the ship had to be launched sideways into the narrow river. (See pictures The SS Great Eastern).

    The launch was scheduled to take place on 3 November 1857 but the enormous ship refused to budge. Two more unsuccessful launch attempts were made first using winches and then hydraulic rams. The ship was finally launched on 31 January 1858, using more powerful hydraulic rams. Fitting out and sea trials took place during the following year and the ship made its maiden voyage in September 1859. This was unfortunately marred by an huge explosion which blew one of the funnels into the air and released steam which killed five stokers, one was drowned and several others were seriously injured. Six days later Brunel, who had been stressed by a series of difficult engineering and financial problems and was already in poor health, suffered a stroke and died at the age of 53.

    In operation the Great Eastern was beset by accidents and failures both technical and commercial. In 1961 it sustained serious damage in a storm losing one of its paddle wheels, smashing the other one and breaking the main rudder shaft to the consternation of passengers. The following year, the New York pilot inadvertently steered the ship onto rocks which opened a gash in the ship's outer hull over 9 feet (2.7 m) wide and 83 feet (25 m) long, some 60 times the area of the damage which caused the sinking of the single hulled Titanic after its collision with an iceberg. Fortunately the Great Eastern's double hull saved it from a similar fate.

    Though it may have been an engineering wonder, the Great Eastern was not a commercial success. There was insufficient traffic to fill its great bulk and, in any case, most of the docks and harbours in the world were not big enough to accommodate a ship six times bigger than anything known before so it never sailed on the long routes for which it was planned.

    In 1864 the Great Eastern was sold by auction for £25,000 to Brunel's railway locomotive engineer Daniel Gooch who converted it into a cable laying ship. One of its funnels and some of the boilers were removed and the sumptuous passenger rooms and saloons were ripped out to make way for three huge iron tanks to carry 2,600 miles (4300 km) of cable and the cable paying-out gear on the decks. In 1866 the Great Eastern was used to lay the first successful transatlantic telegraph cable replacing the damaged cable of 1858.

Stepping beyond the boundaries of familiar surroundings into uncharted territory is always subject to meeting unexpected hazards and the possibility of making a wrong turn. Brunel was not immune from this and sometimes rode into a dead end. Unfortunately because of his forceful character he often took a lot of people with him. A couple of examples follow:

Abandoned Projects

In "Man and Superman", George Bernard Shaw wrote "The reasonable man adapts himself to the world: the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.". Perhaps he was thinking of Brunel when he wrote it.

(See picture Brunel - Engineering Superman)

1823 Johann Wolfgang Döbereiner discovered that hydrogen gas "spontaneously" ignited in the oxygen of the air when it passes over finely spread metallic platinum. He used the phenomenon, an example of what we now call catalysis although he was not aware of it, in the design of a "Platinum Firelighter".

1824 Pure Silicon first isolated by Berzelius who thought it to be a metal while Davy thought it to be an insulator.

1824 While steam engines were still in their infancy, twenty eight year old French physicist and military engineer, Nicolas Léonard Sadi Carnot published "Réflexions sur la Puissance Motrice du Feu" ("Reflections on the Motive Power of Fire") in which he developed the concept of an idealised heat engine: the first theoretical treatment of heat engines. He pointed out that the efficiency of a heat engine depends on the temperature difference of the working fluid before and after the energy conversion process. This was later stated as:

η = (Th - Tc)/Th      or      η = 1 - Tc/Th

where η is the maximum efficiency which can be achieved by the energy conversion, Th is the input (hot) temperature of the working fluid in degrees Kelvin and Tc is its output (cold) temperature. This became known as Carnot's Efficiency Law and still holds good today for modern steam turbines and geothermal energy conversion. Carnot also showed that in a reversible process some energy would always be lost providing an early insight into the Second Law of Thermodynamics.

See also Heat engines.

See more about Steam Engines


1825 Ampère showed that the plane of a magnetic field is perpendicular to the direction of its associated electric current and that the electric current is proportional to the changing magnetic field that produces it, or alternatively, the magnetic field in the space surrounding an electric current is proportional to the current which produces it. The following relationship applies:

cB.dl = μ0.Ienc


C is a closed curve on the plane of the surface enclosing the magnetic field.

c is the line integral around the closed curve C.

B is the magnetic flux density (strength) of the magnetic field.

dl is an infinitesimal vector element (tangent with length l) of the curve C.

μ0 is the magnetic constant or permeability of the medium supporting the field.

Ienc is the total current passing through the surface bounded by the curve C

Now known as Ampère's Law, it laid the foundation of electromagnetic theory. Ten years later Gauss derived an equivalent equation for electric fields.

1825 British electrician, William Sturgeon credited with inventing the first practical electromagnet (5 years after Arago), a coil, powered by a single cell battery, wrapped around a horseshoe magnet. The world's first controllable electric device.

1825 Aluminium was first discovered by Øersted.

1825 The Stockton and Darlington Railway, the world's first public railway was opened with George Stephenson at the controls of his steam engine the Locomotion pulling 36 wagons - twelve carrying coal and flour, six for guests and fourteen wagons full of workmen.

Stephenson was self taught and didn't learn to read and write until he was eighteen. Working as an engineman at the colliery in 1813 he was over thirty years old when he was permitted to tinker with the mine's steam engines. One of his early innovations was to use wrought iron rail tracks to replace the brittle cast iron tracks, originally designed for horse drawn wagon ways, to enable them to carry the heavier steam engines.

In 1815 he designed a miners' safety lamp which could be used in coal mines where the seeping of methane gas from the deep coal seams could result in an explosive atmosphere. A year later the well connected Humphry Davy designed a similar lamp which was named the Davy lamp in his honour overlooking the contribution of the diffident Stephenson.

For the Rainhill Trials in 1829, a competition to select the engine for the new Liverpool Manchester railway, Stephenson designed the Rocket a steam engine which reached a speed of 29 m.p.h. (46 km/h) and won the competition outright. This was the first time that people had been conveyed in a vehicle at speeds greater than could be achieved on horseback and caused great excitement. (See diagram of Stephenson's Rocket).

Its performance and adoption by the railway company started a frenzy of railway building - revolutionising the transport of goods, changing the patterns of industrial development, bringing travel within the possibility of the masses and with it - new aspirations. Together with Watt's steam engine, Volta's battery and Faraday's electric motor, the development of the railways was a key driver in the Industrial Revolution.

Stephenson's Rocket used many of the innovations pioneered by Richard Trevithick and established the basic configuration of the steam locomotive. As in Trevithick's Pen-y-Darren engine it used steel wheels on steel rails, high pressure steam, double acting pistons and a "blast pipe" in the chimney. Improved features included flanged wheels rather than the flanged tracks used by Trevethick, a multi-tube boiler with 25 small diameter fire tubes running the length of the boiler to improve the heat transfer from the firebox gases into the boiler water and a more reliable drive system. For lightness and simplicity, only the two front wheels were driven and the drive was by means two horizontal pistons one on either side of the boiler through crank mechanisms directly coupling the piston connecting rods to the wheels.

The basic design principles embodied in the Rocket were soon adopted for steam trains in many countries of the world and endured until the demise of steam trains in the 1960s and the standard (or Stephenson) gauge (the distance between the rail tracks) of 4 ft 8½ in (1,435 mm) adopted by Stephenson for his railways is used in sixty percent of the worlds railways.

In later years George Stephenson was ably aided by his son Robert who contributed to the design of the Rocket and was particularly active in organising the civil works and building bridges to carry the Stephenson's tracks, spreading the railway network throughout the world.

See more about Steam Engines


1825-1843 The Thames Tunnel, the first successful tunnel underneath a navigable river was designed and constructed by Marc Isambard Brunel.

In response to the demand for a much needed land link between the London docks of Rotherhithe and Wapping on opposite sides of the river Thames, Brunel teamed up with a most unlikely partner, Scottish Thomas (Lord) Cochrane (see following footnote), to design a tunneling shield, which they patented in 1818, to facilitate the construction of a tunnel under the river.

They took their inspiration from the feeding and digestive process of the shipworm, "teredo navalis", which, it was claimed, "had sunk more ships than all the cannon ever cast". The shipworm was a huge mollusc, nine inches (230 mm) long and half an inch (13 mm) in diameter. Its body was soft and transparent but its head was formed by jagged shells which bored into, and ground up, the wood which it ate as it bored its way into the ship's timbers, lining and protecting the pathway it left in the bore behind it with petrified excreta.

Their design for the shield envisaged a large frame, weighing 80 tons, with 3 levels, each level with 12 cells or platforms in each of which a miner excavated the wall in front of him. The cells would be open at the back but closed at the front with removable horizontal boards to stabilise the earth on front and to limit water ingress. The boards could be removed one at a time to enable removal of a strip of earth to a depth of 4½ inches (11.5 cm) and then replaced so that the next strip could be excavated. The frame would then be moved forward 4½ inches by hydraulic rams or screw jacks and a masonry lining would be applied to the section of the walls of the tunnel just vacated by the frame to seal it and give it strength after which the process would be repeated until the tunnel was complete.

By 1823, Brunel had produced plans for the tunnel and the Thames Tunnel Company was formed in 1824 with financing secured from prominent private investors who included a local businessman, brother George of William Hyde Wollaston, Vice-president of the Royal Society and son Timothy of Joseph Bramah, inventor of the hydraulic press. They were joined in 1928 when the project as running out of money by others including Henry Maudslay who had made the machines for Brunel's block making factory and the Duke of Wellington, The Iron Duke, hero of the Battle of Waterloo who was by then British Prime Minister. Work commenced in 1825 using Brunel's new tunneling shield and steam driven water pumps to provide the drainage, both manufactured by Maudslay.

Brunel's son Isambard Kingdom Brunel had worked on the planning and design stages of the project with his father and in 1826 at the age of 19 was appointed Resident Engineer in charge of delivering the project.

The work was unfortunately fraught with difficulties. The tunnel was 75 feet (23 m) below the river's surface at high tide but only 14 feet (4.27 M) below the deepest part of the river bed and ran the 1,300 feet (396 m) of its length through gravel, sand, clay and mud. Conditions in the tunnel were most unhealthy and at times highly dangerous suffering from poor ventilation and the constant leaking sewage laden water and several times from flooding when the water broke through the roof. At the time the river itself was like an open sewer, devoid of fish and wildlife. (It was not until 1858, the year of "the Great Stink" that work was started on Joseph Bazalgette's plan for the construction of London's sewage system to manage waste and clean up the river). Accidents were common, many of them fatal. Isambard who often spent 20 hours per day working at the site submitted himself to the same conditions as his workers and paid attention to their needs, meeting and providing for the casualties which inevitably occurred. He was caught himself in one devastating inundation in 1828 and was seriously injured and lucky to escape with his life. Others were not so lucky. All this resulted in delays and cost over-runs until later in 1828 the company ran out of money. Despite pleas from its high profile backers, the company was not able to raise enough cash to carry on and work was suspended for seven years until the project was rescued by Government aid in 1835. This enabled the work to be re-started with a new tunneling shield weighing 140 tons and the tunnel was finally completed in 1843.

Although it was originally intended for pedestrian and horse drawn traffic it eventually became part of London's underground railway system and is still in use today.

  • Footnote:
  • Lord Cochrane was an audacious, charismatic and successful captain in the Royal Navy during the Napoleonic wars and a radical member of the British Parliament to which (aided by bribery) he was elected in 1806. He was however dismissed from both the Navy and Parliament in 1814 after being convicted of fraudulent share trading on the London Stock Exchange. He and his accomplices were charged with perpetrating an elaborate hoax by faking a report that Napoleon had been killed in battle, (a year before the Battle of Waterloo). In the days before the electric telegraph, this could not be verified, and the price of government stocks rose substantially on the news enabling Cochrane and his co-conspirators to sell, at a huge profit, shares which they had acquired just one month before. After his conviction Cochrane returned to the sea, taking charge of the Chilean Navy in late 1818 in their successful revolutionary war of independence from Spain and in 1823 repeating the exploits in Brazil's war of independence from Portugal. A similar role fighting for Greece in their 1827 campaign for independence from the Ottoman Empire had less spectacular results but nevertheless contributed to their success. His exploits became the inspiration for novelist C. S. Forester's fictional hero Horatio Hornblower.

1826 Italian physicist Leopoldo Nobili together with fellow Italian Macedonio Melloni developed a thermoelectric battery based on the Seebeck effect, constructed from a bank of thermocouples each of which provided a very low voltage of about 50 milliVolts. Nobili also invented a very sensitive astatic galvanometer which compensated for the effect of the Earth's magnetic field. The pointer was a compass needle suspended on a torsion wire in the current carrying coil. A second compass needle outside of the coil compensated for any external fields.

1826 German physicist and chemist Johann Christian Poggendorff invented the mirror galvanometer for detecting an electric current.

1826 At the age of fourteen Albert Krupp dropped out of school and took over responsibility for running the Krupp family's steel making business at Essen in Germany after the death of his father Friedrich Krupp. When he arrived on the scene, the company was in debt and on the verge of bankruptcy and had only seven unhappy employees including five smelters and two forgers. The smelters were furnace men who controlled the steel production and its composition, which in turn determined its properties. The forgers were skilled blacksmiths who shaped the metal. By the time of his death in 1887, Albert had built the business up to be Europe's largest industrial company with 75,000 employees of which 20,000 were based at the Essen steelworks and the rest employed in other branch steelworks, iron ore and coal mining operations in Germany and Spain, owned by the company, as well as on railroads and a small fleet of ships bringing the raw materials to the factories. Half of this enormous business was involved in manufacturing armaments which were supplied to the armies and navies of 46 nations.

Albert's forebears had some experience in arms and steel making but the road to 1826 had been a bumpy one. The first Krupp venture into the armaments trade was made by Anton Krupp, eldest son of Arndt Krupp, a wealthy Essen trader in in wine, groceries, property, and money lending. The Krupp family had settled in Essen during the sixteenth century, just before an outbreak of the black death plague and, despite the adversity, had prospered by buying up the property of families fleeing from the plague.

In 1612, Anton married Gertrud Krösen the daughter of a local gunsmith and consequently became involved in his father-in-law's business manufacturing guns. Essen was one of the two gun making centres in Germany (the other was Suhl) and guns had been made there since 1470 and by 1608 there were 24 gunsmiths in Essen selling firearms to armies and princes. Six years later most of Europe was convulsed in the calamitous Thirty Years War (1618 to 1648) which wiped out over 20% of the German population. Essen was unfortunately located in the midst of this devastation between the warring Protestant and Catholic forces but its gunsmiths and arms merchants flourished selling weapons to the armies of both sides in the conflict. By 1620 the number of Essen gunsmiths had risen to 54 producing 14,000 gun barrels per year, of which 1,000 per year were made by Anton's factory. See how gun barrels are made.

After the war the Krupp family did not pursue gun making but for the next four generations they concentrated on trading and on offices of public administration. It was 150 years before they made their first foray into iron and steel making.

In 1751, Jodocus Krupp married Helene Amalie Ascherfeld, both direct descendants of Arndt Krupp. The unfortunate Amalie outlived both her husband and her son and inherited the Krupp's considerable wealth becoming known as the Widow Krupp. A determined business woman, she expanded the family's holdings in textile production and coal mines and in 1799 she acquired the Gutehoffnung (Good Hope) ironworks, to which she had provided a mortgage, as a settlement when the firm went bankrupt. Located on a stream near Essen, it incorporated a foundry and blast furnace which made cast iron pots, boilers and weights.

In 1800 the reorganised Good Hope forge started operations using local ores making kitchenware, stoves, weights, farm tools and cannon balls returning the business to profit. It was Krupp's first iron making plant.

In 1807 Widow Krupp's grandson Friedrich Krupp, at the age of 19, was put in charge of the forge and the operation went downhill. He had ambition and a vision of making more technical products for the new steam age including pistons, cylinders, engine parts and steam pipes, but he had no technical knowledge of iron making and his management skills were disastrous. The business started losing money and the wily Widow sold it for a profit a year later when he was ill.

In 1810 The hapless Friedrich inherited the family fortune after the death of his grandmother which gave him the opportunity to get back into the iron and steel business. Not only did he have the cash to indulge his passion, but advantageous market conditions made it an attractive prospect. At that time, Napoleon Bonaparte had implemented a blockade against Britain, denying it's goods access to mainland Europe. These goods included crucible steel which was used to make high value items such as cutlery, tools and scissors and were highly prized in Europe for their high quality and strength. Crucible steel had mostly been imported from England and was known as "English Steel" since Benjamin Huntsman, who pioneered the process in 1740, had managed to keep it a secret. In response to the continuing demand in Europe, Napoleon offered a prize of four thousand francs to anyone who could replicate the process, a prize which reinforced Friedrich's interest.

In 1811 Friedrich used his inheritance to found the Krupp Gusstahlfabrik (Cast Steel Works) with the premature, if not misleading, claims "for the manufacture of English Cast Steel and all products made thereof" and that he possessed the secret process of English Steel. Unfortunately Friedrich was more of a dreamer than a businessman and he proceeded to squander the Krupp family's entire fortune.

Since the crucible steel casting process was unknown in Germany at the time, to get the business off the ground, he offered partnerships to two self proclaimed "metallurgy experts", the von Köchel brothers, who claimed to know the secret formula. Together they built a foundry on the banks of the Ruhr River in Essen with a furnace for making blister steel by the cementation process, together with smelting furnaces and a large water powered forging hammer but things soon started to go wrong. Some blister steel was produced by conventional means but this was mainly produced to feed the crucible process and had limited sales prospects. It turned out however that the von Köchel brothers were frauds and knew nothing about metallurgy or crucible steel manufacturing, and though they produced unusable steel, they remained in the company until 1814, leaving it in debt. The following year Friedrich was swindled a second time by a new partner, a Prussian Hussar called Nicolai, with fake credentials who left him with more unusable steel and even greater debts.

Even the Ruhr River flow proved unreliable leaving the plant without power for the furnace bellows and the forging hammer for prolonged periods causing missed delivery dates. This forced Friedrich to subcontract his hammer work since he was unable to afford the purchase of a steam powered hammer.

Eventually in 1816 after five years of experimenting, he was able to smelt his first steel and began to produce files, drills, tools, dies, coin presses and rolling mill blanks. By that time, a year after the Battle of Waterloo, Napoleon and the blockade were long gone and imported cast steel was available once more.

In 1818, buoyed up by his modest success Friedrich constructed a massive new factory on Essen's Berne river, designed to accommodate sixty smelting furnaces, though he only had sufficient work for eight of them, and a huge 800 pound (360 Kg) water powered forging hammer. He did manage to achieve some sales, mostly steel dies for coin making at the Prussian mint and some orders for steel for bayonets and gun-barrels from the royal ordnance factories on the Rhine, but the Berne river flow was just as unreliable as the Ruhr. Operations were intermittent and the company was losing money and his credit was running out. In response he increased prices and attempted to reduce costs by compromising on the product quality by adulterating the materials with scrap steel. The result was decreasing sales and ever increasing losses.

Friedrich was obsessed with technology and spent much of his time in the plant neglecting the wider responsibilities of the business. He had no appreciation of the importance of financial controls or of securing markets, supplies of raw materials and fuels. By the time of his death at the age of 39 in 1826 the Krupp Gusstahlfabrik had been in operation for 15 years. It had only seven employees. It was in debt and virtually bankrupt and the Krupp family fortune was gone.

It was from these inauspicious circumstances that, assisted initially by his mother Thérèse Krupp, the new Widow Krupp, the impoverished young Alfred Krupp built the company into one of the world's greatest engineering enterprises.

Widow Krupp didn't make it easy for young Alfred. She announced that his father, Friedrich, had passed on to him "the secret of manufacturing cast steel", a claim which was hard for the 14 year old to live up to. Fortunately he did not inherit the weaknesses of his father. He was a perfectionist but he was also practical, painstaking and thorough. He took his new responsibilities seriously and his devotion to the company became an obsession. He spent his entire waking hours working on company business, toiling alongside the workmen during the day, writing letters to customers and carrying on his father's experiments to find or improve the "secret process" at night. As control of the factory improved he began to devote more time to establishing a sales network, travelling widely and frequently throughout Europe, building the company through technology and market developments with disciplined management and financial controls.

Technology Developments

Progress was slow at first. The factory was no more than an artisan workshop with a limited product line, mostly flatware, consisting only of a few tools and knives and occasional coin dies for the mint.

  • Product Strategy
  • To revive the company, Alfred borrowed money from other family members to invest in new technology to expand and diversify the product line, a strategy which became typical of his management, but for many years the factory scarcely paid its way and did not break even until 1837. His first major development, which came in 1830, was the production of steel rolls, for use in rolling mills, which he later customised for manufacturing spoons, forks and coin dies for local markets. He backed up his sales effort by guaranteeing quality workmanship.

    The opportunities in the railway and armaments businesses which eventually became Krupp's main source of revenue did not arise for almost 20 years.

  • Steelmaking Process
  • Expertise in metallurgy and steelmaking were the foundations on which the Krupp enterprise was based and Alfred continued to work long and hard to develop and perfect new technologies and to build a strong patent portfolio. As late as 1838 he went on a spying trip to England where he stayed for five months in attempt to discover the secret of Huntsman's crucible steel. By that time however the principle of the process, if not the practice, was fairly well known and he didn't learn anything more than he already knew. He jealously guarded his own technology developments however as well as his the company's financial status and his staff were sworn to secrecy.

    Where he did make a breakthrough was in the production of very large steel castings. By the early 1850s, the only way to make high quality cast steel was by Huntsman's crucible process, but the largest practical crucibles available could only contain between about 40 to 50 pounds (18 to 23 Kg) of the melted steel. In order to make a large solid ingot, the molten steel must be poured continuously into the mould so that the mould is completely filled before any part of the ingot begins to solidify, otherwise the structure of the ingot will not be homogeneous and hence would be weaker. In practice this meant that it was only possible to cast small objects with steel from a few crucibles before the steel temperature dropped too low.

    In 1851, Alfred astonished attendees at London's Great Exhibition with his display of a flawless cast steel ingot weighing 4,300 pounds (1,950 Kg) and a muzzle loading six pounder cannon made of cast steel, previously thought to be not possible. This was an achievement of logistics rather than metallurgy. Using 50 pound crucibles it would require 86 crucibles heated in over 20 furnaces, each containing four crucibles, to be brought to the required temperature simultaneously and a gang of 50 men working in pairs with military precision to take the crucibles from the furnaces, to carry them to the mould and pour in their contents within the short timescale allowed before any of the steel begin to solidify.

    This exhibition caused a sensation in the industrial world bringing fame to Krupp and the Essen works and was a major turning point for the business.

    In 1862 Alfred Krupp was the first to use the Bessemer process for the mass-production of steel in continental Europe. This replaced the slow and costly crucible steel process and gave Krupp a competitive edge.

    In 1869 He also pioneered the use of the new open-hearth process of steel casting bringing further productivity gains.

  • Machinery
  • Alfred also invested in, and developed, new machines to improve the efficiency and scope of his operations. As sales increased, in 1835 he was able to buy a steam engine to power his forging hammer eliminating his dependence on the unreliable river flow.

    In 1841 a Munich goldsmith and engraver named Wiemer, commissioned some custom engraved rolls for producing three dimensional shapes from flat plate by engraving the shape and pattern of the article to be produced in relief on the rolls. After the rolls were delivered, Alfred's brother Hermann adapted the process for the manufacturing of steel spoons, cutlery and other parts for silverware enabling Krupp to open a large silverware factory in a joint venture with a Viennese entrepreneur Alexander Scheller to produce goods for export.

    In 1861, as Krupp took on projects for the railways and the army requiring larger castings and forgings, Alfred developed "Fritz", a steam forging hammer with a 50-ton blow. For many years it was the most powerful in the world.

  • Railway Tyres
  • The beginning of the construction of the German railway system in 1835 brought new opportunities for the Krupp factory which produced steel axles and springs for the rolling stock, but Krupp's biggest breakthrough which propelled the company into the big league was the invention in 1851 of the weldless steel tyre which he patented the following year.

    Early railroad carriage wheels had been made from a single piece of cast iron which is very brittle and unsuitable for carrying dynamic and shock loads causing them to break or wear out very quickly. This excessive wear problem was initially overcome by redesigning the wheels to incorporate more durable, replaceable steel tyres in the form of a hoop fitted around the rim of the wheel disc. The tyre included both the surface bearing on the track as well as the flange which kept it on the rails. These tyres were manufactured by heating and bending a steel bar with a suitable cross section into a circular hoop and welding the ends together, or alternatively, by a two piece construction using two shorter bars forged into semicircular arcs and welded together to form the hoop. The steel tyres were then heat shrunk onto the cast iron wheel. Though this was an improvement, the wheels were still vulnerable to wear and breakage because of the weakness of the welds. Replacing a damaged tyre put the train off the tracks for several days causing a major service interruption.

    In his search for a better solution, Alfred carried out his experiments using lead, so that he could easily melt down his failures, and avoid losing the material. The seamless steel tyres he developed were cast in a single piece and forged so they did not need welding. The tyre was machined with a shoulder on its outer face to locate it on the wheel rim, and a groove on the inside diameter under the flange face. See diagram. The internal diameter of the tyre was machined to be slightly less than the diameter of the wheel on which it was to be mounted, to give an interference fit. The tyre was fitted by heating it causing it to expand so it could be slipped over the wheel. After the tyre cooled, a shaped steel bar rolled into a hoop was fitted into the groove to act as a retaining ring and hydraulically operated rolls swaged the groove down onto the ring.

    Krupp's weldless cast steel tyres could withstand the ever increasing speeds achieved by the trains. Unlike welded steel tyres, they did not fracture under pressure and lasted four times longer than the tyres they replaced.

    Seamless tyres quickly became the source of Krupp's primary revenue stream, mainly from sales to railways in the United States and profits from this business funded the development of armaments. By the 1870s, thanks to the capacity of the Bessemer and open hearth converters to produce huge volumes of steel, Krupp was also shipping over 170,000 tons of steel rails per year to the United States until they were eventually overtaken by the rapidly growing U.S. steel industry.

  • Armaments
  • Krupp's entry into the manufacture of arms was much slower. He started in a small way between 1836 and 1842 producing hollow forged muskets and in 1843 he made his first rifle with a cast steel barrel which was sent to the Prussian state military agents. This was followed up in 1847 with the first cannon made of cast steel, a muzzle-loading 3 pounder but the Prussian military were not impressed by this new technology. Like the British and French armies they preferred tried and tested heavy cannons, cast from bronze, over the new lightweight guns. His next steel cannon was the 6 pounder which caused a sensation when it was demonstrated at the 1851 Exhibition in London. Despite the acclaim there were no customers and Alfred gave it to the King Frederick William of Prussia who used it as a decorative piece.

    Undeterred, Krupp consequently sold his guns to other international customers, some of whom were potential enemies of Prussia. Four years later, Albert produced a cast steel smooth bore muzzle loading 12 pounder cannon for the 1855 Paris Exhibition, which was 200 pounds (90 Kg) lighter than the equivalent bronze gun. He also created a stir when the 10,000 pound (4,500 Kg) cast steel ingot he was exhibiting crashed through the exhibition's wooden floor crushing all in its way. After the exhibition, the Turkish viceroy of Egypt purchased 36 of the guns. Further contracts followed over the next few years with Belgium, Russia, Holland, Spain, Austria, Switzerland, Württemberg, Hanover and Great Britain.

    Wilhelm I, the Prussian King's brother, who became Prince Regent in 1858 after the King suffered a stroke, was more favourably disposed to new technology, recognising the strategic importance of supporting arms manufacturing in Prussia, but still, the Prussian military did not trust the proposed breech loading or the rifled barrels which promised superior performance to the conventional muzzle loaded smooth bore bronze cannon generally in use at the time.

    Krupp's method of loading the powder charge was an improvement over William Armstrong's 1855 design and used a metal cartridge case in which to load the charge. On firing, the cartridge case expanded against the chamber wall and effectively sealed the breech. It also left less debris in the gun barrel after firing. Krupp's metal cartridge concept is still used in modern day artillery.

    Krupp lobbied hard to overcome the conservativism of the military and in 1859 Wilhelm overrode the military objections and bought Prussia's first 312 cast steel 6 pounder rifled, breech loading cannons from Krupp who became the main arms manufacturer for the Prussian military.

    At the request of the Russians, Krupp adopted Armstrong's "Built up" construction to improve the burst strength of the gun barrels by heat shrinking a white hot outer tube of steel over the cold breech end of the barrel to reinforce it. His guns became known as "ringed" guns.

    The first test of Krupp's breech loading cannons under battle conditions came in the 1866 Austro-Prussian War when Krupp's guns were used by both sides in the conflict. Unfortunately a weakness in the design of the breech mechanism caused several of them to explode, injuring or killing the gunners.

    The problem had been solved by the time of the next major conflict, the Franco-Prussian War of 1870-1871 when Prussia's cast steel, breech loading Krupp cannon pulverised Napoleon III's muzzle loading bronze artillery. The significance was not lost on other governments and armies and orders started pouring in for Krupp guns and Alfred Krupp became known as the "Cannon King".

    Having established his credibility as an arms supplier, Krupp did not rest on his laurels but continued his relentless pursuit of technology excellence building bigger and better guns, exploiting the perceived threats between nations by creating faster obsolescence thus generating more sales and more frequent replacements.

    • Footnote
    • Essen was an Imperial City of the Holy Roman Empire which was annexed by Prussia in 1802.

      Between 1701 and 1918, Prussia was a German Kingdom or state which included parts of present day Germany, Poland, Russia, Lithuania, Denmark, Belgium and the Czech Republic.

      After the 1871 war, Prussia took over the whole of Germany, Prince Wilhelm I who had become the Prussian King in 1861 on the death of his brother, became the Emperor of Germany and Otto von Bismarck the Prussian Prime Minister became the German Chancellor.

Business Practices

Short term profits were never the top priority of the company. It didn't have shareholders clamouring for dividends. It was a family business and security annd continuity were important but its main motivation was to be the best in the world and and to earn the status, influence and honour which went with that achievement. Krupp's company ethos also included a sense of social responsibility and a paternal concern for the wellbeing of its workers for whom it provided generous benefits but this was not entirely altruistic.

  • Sales and Marketing
  • From the early days, Alfred Krupp doggedly pursued international markets, personally travelling abroad, participating in international exhibitions and establishing sales outlets in Europe and overseas. He cultivated friendships in high places. In his native Prussia he stressed his patriotism and won the support of Prince Wilhelm I, though behind his back, business interests took priority and he sold arms to potential enemies of Prussia. He had "common cause" with Bismarck who is quoted as saying "The solution of the great problems of these days is not to be found in speeches and majority rulings, but in blood and iron!" winning him the patronage of the German government. He ingratiated himself with heads of state and military leaders from other nations often giving them examples of the latest Krupp guns.

    To promote his international business he also built a huge weapons proving range to which he invited heads of government and senior military commanders to attend demonstrations of the fire power and capability of his weapons. Guests were treated to lavish hospitality.

  • Vertical Integration
  • As the business grew and the demand for raw materials increased, Albert recognised the dangers of depending on external suppliers and the importance of securing the supply chain. He also wanted to control all aspects of the manufacturing process within his own company to achieve efficiency gains and to ensure quality. In the 1840s he therefore began to acquire ore deposits, coal mines and coke ovens as well as competing iron and steel works to expand his operations.

    In 1872 after the war, business was booming and he bought over 300 ore deposits in various parts of Germany and acquired a holding in the Orconera Iron Ore Company, which owned large concessions in superior low phosphorus iron ore deposits in Spain, often paying over the odds. He even bought the large "Hanover" coal mine even though he already had secure supply contracts with several collieries.

    The same year he also expanded operations by buying two of his competitors' steel works, the Johanneshütte Ironworks with four blast furnaces and the Hermannshütte Ironworks with three.

    The following year he set up his own shipping company in Rotterdam and built a small fleet of four ships to transport his iron ore from Orconera in Spain.

  • Business Funding
  • The Krupp business was forever short of cash even when it was profitable. Family members steadfastly refused to dilute the Krupp family holding or to relinquish any control of the company by putting it into a joint stock company. They were also suspicious of banks. During the early days when the company made losses they made many pleas for government support which usually fell on deaf ears and they depended on family loans to survive. When the company eventually became profitable, the profits were ploughed back into developing the business. Even when sales and profits began to grow rapidly, the cash generated by the business was needed to fund the ambitious expansion plans. This caused a particularly critical problem during the economic panic of 1873 when the euphoria of the 1872 boom wore off and many companies went bankrupt. Krupp's finances were grossly over extended by their profligate purchasing spree in 1872 and they were rescued by the Prussian State Bank. Between 1876 and 1896 German tariffs protected the steel industry from British and American competition keeping Krupp and others profitable during times of recession.

    Krupp continued to look to the government for state support and once its importance as the state's main arms supplier was established, government funding was forthcoming and the connection between the firm and the State of Prussia became increasingly more close and intimate.

  • Industrial Relations and Social Policy
  • Alfred Krupp was a pioneer in providing social benefits for his employees. He had started in 1836 with a voluntary sickness and burial fund and over the years he progressively increased these benefits with company funded health insurance and a pension fund for retired and incapacitated workers.

    In 1845 the company still employed only 122 workmen but by 1865 the work force had risen to over 8,000 reaching 16,000 in 1871. With the rapid expansion of the company it was becoming difficult to house and motivate the increasing workforce so that in the 1860s benefits were further increased to include subsidised housing, hostels for unmarried employees, free health and retirement benefits, widows and orphans benefits, hospitals, schools, libraries, parks, recreation clubs and stores. In return he imposed strict discipline and demanded absolute dedication and loyalty to the company and he got it. Trade unions were not necessary and company loyalty was fanatical.

Krupp Epilogue

After Alfred's death the enormous expansion of the company continued under the supervision of Krupp family members with warships, armour plating, submarines, tanks, railway locomotives, heavy trucks and ever larger guns and ammunition added to the product portfolio. The production of armaments became even more important, boosted by the requirements of World War I and World War II. Krupp almost became an arm of the German government and was closely associated with the Nazi party.

  • Great Guns
    • Paris Gun - Known by the Germans as Wilhelmgeschütze (William's Gun after Wilhelm II - "Kaiser Bill")
    • In 1918 Krupp produced a gun weighing 256 tons intended for bombarding Paris. Fired by a massive 180 Kg (400 lbs) powder charge, its 106 Kg (264 pounder) projectiles had a muzzle velocity of 1,640 m/s (5,400 ft/s), equivalent to Mach 5.0, giving the shells a range of 130 kms (81 miles). During their 182 second trajectory to the target, the shells soared to an altitude of over 42 kms (26 miles), into the stratosphere, the highest point ever reached by a projectile before the rocket powered V2 which had a maximum speed of Mach 5.5 .

      The barrel was 34 m (112 ft) long with a bore of 211 mm (8.3 in), later re-bored to 238 mm (9.4 in). It was so long that it needed an overhead suspension, support truss to prevent it from drooping.

      See a photo of Krupp's Paris Gun.

    • Gustav Gun
    • In 1934 Adolf Hitler commissioned the world's biggest ever gun, capable of piercing one meter (3.3 ft) of steel, seven meters of concrete, or thirty meters of dense earth which Krupp was able to deliver in 1941. Known as the Gustav Gun after Gustav Krupp (See next), it could fire either gigantic 4.8 ton high explosive shells propelled by an explosive charge weighing 700 kg (1,500 lb), or even bigger 7.5 ton concrete piercing shells propelled by a 250 kg (550 lb) charge. The lighter, high explosive shells had a muzzle velocity of 820 m/s (2,700 ft/s) giving them a maximum range of 47 kms (29 miles) and the heavier, armour piercing shells had a muzzle velocity of 720 m/s (2,400 ft/s) providing a range of 38 kms (24 miles).

      This monster gun weighed 1344 tons and was 11.6 metres (38 ft) tall, 7.1 metres (23.3 ft) wide and 47.3 Metres (155 ft.) long with a barrel 32.5 Metres (106.6 ft) long with a calibre of 800 mm (31 in).

      A crew of 500, commanded by a major general, was needed to assemble, load and defend the gun and to excavate and construct a double set of curved railway tracks embedded in concrete to enable the adjustment of its azimuth direction. (The barrel could be moved in elevation but could not swing in azimuth).

      See a photo of Krupp's Monster Gustav Gun.

    • See also Armstrong and Whitworth Guns from previous wars.

During World War I, Gustav Krupp, heir to the business at the time, was one of the German tycoons who took over and plundered the Belgian industry when the country was occupied by German troops and Krupp's weapons were used against neutral targets and non-combatants. After the war, the Krupp factories were broken up by the victors and Gustav Krupp was cited as a war criminal but not prosecuted. He was however forbidden to manufacture arms ever again. Despite this sentence, Krupp participated in the secret rearmament of Germany when Hitler came to power. Indicted once more after WWII for war crimes he escaped trial due to his advanced dementia.

During World War II, the Krupp factories were again feeding Germany's war machine. Krupp's legendary paternal treatment of the workforce however did not extend to the unfortunate masses of slave labour, including POWs, civilians from occupied countries and concentration camp inmates, who were forced to work in Krupp's factories. Eventually the factories were destroyed by allied bombing and Alfried Felix Alwyn Krupp von Bohlen und Halbach, heir to the Krupp dynasty, a member of the German SS, and "Sole Proprietor" of the business, who was in charge at the time was convicted as a war criminal. He was sentenced to 12 years in prison and the confiscation of all of his property.

  • Footnote
  • The name most associated with the growth of the American steelmaking industry is Scottish born Andrew Carnegie. His story is the essence of The American Dream. In 1848 At the age of 13 his parents emigrated to the United States taking Andrew with them when their weaving business fell on hard times. Starting work at the age of 13, working 12 hour shifts, six days a week, in a cotton mill for $1.20 per week as a "bobbin boy" looking after spools of thread, he rose to become the richest person in the world in 1901 (according to J.P. Morgan). It was however as an investor, rather than a technologist that he earned his fortune.

    Carnegie was diligent with a "can do" attitude and an affable personality and his initiative and hard work, together with an element of luck, won him rapid promotions and a circle influential friends.

    His career was meteoric. Thanks to his early schooling in Scotland, he was soon able to assist in clerical work at the cotton mill. After two years he was offered a job as messenger boy with the O'Rielly Telegraph Company where he learned Morse code during the day while studying bookkeeping in a local library at night and at the age of 15 he became a telegraph operator. Two years later in 1853 he moved to the Pennsylvania Railroad Company, also to work there as a telegraph operator and his rise continued. By 1859 he had worked his way up to be Pennsylvania Railroad's Western Superintendent where he saw the importance of the steel industry to America's fast expanding railways.

    On his way up, in 1855 at the age of 20 he was offered a loan by a business friend to buy his first shares in a document delivery company and he quickly developed a passion for investments when he received his first dividend payment,

    By 1862 he had saved enough, together with 5 friends, to make a major investment in his first steel company, Piper & Shiffler, to build steel railroad bridges. This was followed in 1963 by an investment in small iron foundry, the Union Iron Mills.

    In 1865, still working for Pennsylvania Railroad, his annual investment income amounted $40,000, twenty times his already large salary of $2,000 per year. Carnegie then decided to leave and concentrate on investing, particularly in telegraph services and the steel industry, setting up with others, the Edgar Thomson (ET) Steel Company with a huge plant on the outskirts of Pittsburgh. Demand for steel was insatiable, first for railroad tracks and rolling stock, and replacement of the original wooden trestle bridges with steel structures, then for construction projects in the rapidly growing cities. Carnegie acquired several more steel making interests and eventually all of his iron and steel interests were consolidated into a single new company known as Carnegie Steel.

    Carnegie had no experience, nor any particular interest in steelmaking and he treated the steel business purely as an investor. He appointed qualified managers to take care of business operations and the technology. He was however a great promoter of the business and worked to increase profitability by means of ruthless cost cutting and to increase market share by strategic acquisitions of, and mergers with, competitor companies as well as companies supplying raw materials.

    In 1901 Carnegie Steel was bought for $480 million ($13.8 billion in today's money) of which Carnegie's share was $225 million ($6.5 billion) by Wall Street banker J. Pierpoint Morgan heading a consortium involving Carnegie's competitors, American Steel & Wire and the Federal Steel Company, to form US Steel consolidating America's steel industry and eliminating wasteful competition.

    Carnegie spent the rest of his life and most of his money funding educational projects around the English speaking world.

1827 German physicist Georg Simon Ohm discovered the relationship between voltage and current, V=IR, in a conductor which is now called Ohm's Law. The importance of this relationship lies less in the simple proportionality but on Ohm's recognition that Voltage was the driver of current.

1827 Scottish botanist Robert Brown studying the suspension of pollen in water, observed the random movement of the grains we now call Brownian Motion. These random movements which were later quantified using statistical methods are also typical of the movement of electrons and ions in an electrolyte. This causes of this phenomenon were eventually explained in 1905 by Albert Einstein using the kinetic theory of gases.

1828 Berzelius compiled a table of relative atomic weights for all known elements and developed the system of symbols and formulas for describing chemical actions.

1828 German chemist Friedrich Wöhler discovered that the salt, ammonium cyanate, was transformed by heat into urea, a compound which occurs in urine and which had hitherto been known only as a product of animal metabolism. He wrote excitedly to his mentor Berzelius, "I must tell you that I can make urea without the use of kidneys of any animal, be it man or dog". This was the announcement of the birth of modern organic chemistry and was the beginning of the end of Berzelius' popular vitalist hypothesis, that "organic" compounds could be made only by living things.

Wöhler also credited with the isolation of pure aluminium (in 1827, after Øersted's discovery in 1825) and was one of the first to isolate the elements yttrium, beryllium, and titanium and to observe that "silicium" (silicon) can be obtained in crystals.

1828 Self taught English mathematician George Green, who worked in his family's windmill till the age of forty, published in a local journal in Nottingham with only 51 subscribers, mostly family and friends, An Essay on the Application of Mathematical Analysis to the Theories of Electricity and Magnetism. It earned him a place at Cambridge as a mature student but its full importance was not recognised at the time until it was rediscovered by William Thomson (later Lord Kelvin) just after his graduation in 1845. Kelvin recognised this as a seminal influence in the development of electromagnetic theory.

1828 French physiologist and biologist René Joachim Henri Dutrochet discovers osmosis - the diffusion of a solvent through a semi permeable membrane from a region of low solute concentration to a region of high solute concentration. The semi permeable membrane is permeable to the solvent, but not to the solute, resulting in a chemical potential difference across the membrane which drives the diffusion. Thus the solvent flows from the side of the membrane where the solution is weakest to the side where it is strongest, until the solution on both sides of the membrane is the same strength equalising the chemical potential on both sides of the membrane.

Semi permeable membranes are now widely used as separators in batteries and fuel cells allowing the passage of certain ions while blocking others.

1828 Hungarian priest and physicist of Slovak origin, Ányos Jedlik built the first direct current electric motor using an electromagnet for the rotor and a commutator to achieve unidirectional rotation. Jedlik's motor was a shunt wound machine in which a moving electromagnet rotated within a fixed coil, the reverse of modern conventional motors. The wires powering the electromagnet protruded into two small semicircular mercury cups on either side of the shaft. This provided the required commutation as the wires picked up the current from alternate cups as the shaft rotated. Like many motors at the time, it had no practical application, however in 1855 Jedlik built another motor based on similar principles which was capable of carrying out useful work.

In 1861 he demonstrated a self excited dynamo but he did not publish his work. Subsequently Siemens, Varley and Wheatstone were credited with the invention.

Jedlik continued working on high voltage generators and spent his last years in complete seclusion at the priory in Gyór.

1828 Scottish engineer, James Beaumont Neilson patented the hot blast method of air supply to blast furnaces. Preheating the air blown into the furnace, enabled the efficiency of the iron ore smelting process to be improved.

See also Iron and Steel Making

1829 Nobili invents the thermopile, an electrical instrument for measuring radiant heat and infra red radiation. It was also based on the Seebeck effect as in Nobili's thermoelectric battery of three years earlier and consisted of a sensor made up from a bank of thermocouples connected in series which generated an electrical current in response to the heat radiation input. The current was measured by an astatic galvanometer, of Nobili's own design. With improvements from Melloni, it found extensive use in nineteenth century laboratories.

1829 French physicist Antoine-César Becquerel, father of a dynasty of famous scientists, developed the Constant Current Cell. The forerunner of the Daniell cell, it was the first non-polarising battery, maintaining a constant current for over an hour unaffected by polarisation. It was a two electrolyte system with copper and zinc electrodes immersed in copper nitrate and zinc nitrate electrolytes respectively, separated by a semi permeable membrane. It was left to Daniell to explain how it worked and thus to get credit for the idea.

1830 The invention of the thermostat made from a bi-metallic strip, usually brass and copper, was claimed by Andrew Ure a Glasgow chemistry professor. As a control device it did not find much use for 70 years until the advent of electricity supplies to the home when it could be used to operate a switch.

Note however that the bi-metallic strip used as a temperature compensating device in clocks and watches was invented by John Harrison in 1759. See Timekeepers.

1830 Joseph Henry in the USA worked to improve electromagnets and was the first to superimpose coils of wire wrapped on an iron core. It is said that he insulated the wire for one of his magnets using a silk dress belonging to his wife. An early example of insulated wire. In 1830 he observed electromagnetic (mutual) induction between two coils and his demonstration of self-induction predates Faraday, but like much of his work, he did not publish it at the time. An unfortunate tendency which he lived to regret. (See 1835 Morse)

The unit of Inductance the Henry is named in his honour.

1831 Faraday invented the solenoid and independently discovered the principle of Induction and demonstrated it in an induction coil or transformer. The induction coil has since been "invented" by many others (See 1886 William Stanley).

Faraday discovered that the motion of a magnet could induce the flow of electric current in a conductor in the vicinity of the moving magnet. He was the first to generate electricity from a magnetic field by pushing a magnet into a coil. He put this to practical use with his invention of the generator or dynamo, unshackling the generation of electricity from the battery. Faraday's dynamo, named the Faraday Disk after its construction, was a homopolar machine consisting of a copper disk rotating between the poles of a magnet. Current is generated along the radius of the disk where it cuts the magnetic field and is extracted via brushes contacting the shaft and the edge of the disk. See diagram. The Faraday Disk functions equally well as a motor and although the machine is said to be unique in that it is a direct current machine which does not need a commutator, it does owe something to Barlow's 1822 toothed motor design. (See also Siemens 1867).

From his experiments Faraday defined the relationship now known as Faraday's Law of Induction which describes how an electric current produces a magnetic field perpendicular to the direction of the current and, conversely, how a changing magnetic field generates an electric current in a conductor (normally a loop or a coil of wire with multiple turns, making a complete circuit) perpendicular to the field. The voltage generated at the terminals of the conductor is independent of how the change was produced. The change could be produced by moving the coil into or out of a magnetic field, rotating the coil relative to a magnet, changing the magnetic field strength or moving a magnet toward or away from the coil.

Faraday's Law states that the magnitude of the emf induced in a circuit is proportional to the rate of change of the magnetic flux that cuts across the circuit. It was left to Maxwell to express Faraday's Law and his notions of Lines of Force in mathematical terms.

The relationship can be stated as:

E= - N.dΦ/dt


E is the Electromotive Force (Voltage) induced in the coil.

N is the number of turns of wire in the coil.

dΦ/dt is the rate of change of the magnetic flux Φ passing through or enclosed by the coil.

The negative sign - signifies that polarity of the induced emf is such that it produces a current whose magnetic field opposes the change which produces it. (Lenz' Law).

Or alternatively:

E= - N.Δ(A.B)/Δt


Φ = (A.B)


B is the field strength of the external magnetic field.

A is area of the field enclosed by the coil.

Faraday's Law is the theoretical basis on which all modern electrical machines and tranformers are based.

See more about Michael Faraday

1831 Henry demonstrated a simple telegraph system sending a current through a mile and a half of wire to trigger an electromagnet which struck a bell (thereby inventing the electric bell, for many years the main domestic use of the battery). He used a simple coding system switching the current on and off to send messages down the line. Henry thought that patents were an impediment to progress and like Faraday he believed that new ideas should be shared for the benefit of the community. He subsequently freely shared his ideas on telegraphy with S. F. B. Morse who however went on to patent them passing them off as his own.

1831 -1835 Henry developed the relay which was used as an amplifier rather than as a switch as it is used today. At the end of each section, the feeble current would operate a relay which switched a local battery on to the next section of the line renewing the signal level. This enabled signals (currents) to be carried (relayed) over long distances making possible long distance telegraphy. In fact the relay reconstituted the signal rather than amplified it, just as the repeaters used in modern digital circuits do, thus avoiding amplifying the noise. The relay and its use with local battery power to "lengthen the telegraph line" were more of Henry's ideas which he failed to publicise or exploit.

Henry was appointed the first Secretary of the Smithsonian Institution when it was founded in 1846.

For over thirty years telegraphy was the main practical application of the battery, this new found electrical technology.

1832 After witnessing a demonstration of von Sömmering's electrochemical telegraph some time earlier, Baron Schilling an attaché at the Russian embassy in Munich, in turn developed the idea by making an electromagnetic device which he demonstrated in 1832. It was a six wire system which used the movement of five magnetic needles to indicate the transmission of a signal. This was the method subsequently used by Cooke and Wheatstone who later "invented" and patented the five needle electric telegraph for two way communications in 1837.

1832 Hippolyte Pixii built his "magneto generator" the first practical application of Faraday's dynamo. The term "magneto" means that the magnetic force is supplied by a permanent magnet. His first machine rotated a permanent magnet in the field of an electromagnet generating an alternating current for which there was no practical use at the time. The following year at Ampère's suggestion he added a commutator to reverse the direction of the current with each half revolution enabling unidirectional - direct current to be produced. Pixii's magneto liberated electrical experimenters from their dependence on batteries.

1833 Faraday published his quantitative Laws of Electrolysis which express the magnitudes of electrolytic effects and galvanic reactions, putting Volta's discoveries and battery theory on a firm scientific basis.

  • The amount of a substance deposited on each electrode of an electrolytic cell is directly proportional to the quantity of electricity passed through the cell.
  • Faraday's Constant, named in his honour, represents the electric charge carried on one mole of electrons. It is found by multiplying Avogadro's constant by the charge carried on a single electron, and is equal to 9.648 x 104 Coulombs per mole. It is used to calculate the electric charge needed to discharge a particular quantity of ions during electrolysis.

  • The quantities of different elements deposited by a given amount of electricity are in the ratio of their chemical equivalent weights.

With William Whewell, he also coined the words, electrode, electrolyte, anode (Greek - Way in), cathode (Greek - Way out) and ion (Greek - I go) .

1833 Samuel Hunter Christie of the British Royal Military Academy publishes a bridge circuit for comparing or determining resistance, later to be called the Wheatstone Bridge.

1833 German physicist Wilhelm Eduard Weber, working with Gauss, demonstrated "the world's first electric telegraph" using a moving magnet and a coil of wire to send a signal along a wire suspended from a church spire in Gottingen to the other side of the town, a distance of 3 kilometers. One of many such claims before and since. The system used a simple coding scheme switching the current on and off, similar to Henry's, combined with reversing the polarity of the current to deflect a compass needle in opposite directions, to send different letters down a single wire. Over the subsequent years Weber investigated terrestrial and induced magnetic fields and verified the theoretical laws put forward by Ampère and others using electrical instruments which he designed for this purpose. The unit of Magnetic Flux is named the Weber in his honour.

1833 Russian physicist Heinrich Friedrich Emil Lenz formulated Lenz Law which states that an induced electric current flows in a direction such that the current opposes the change that induced it. A special case of the Law of Conservation of Energy. The law explains that when a conductor is pushed into a strong magnetic field, it will be repelled and that when a conductor is pulled out of a strong magnetic field that the magnetic forces created by the induced currents will oppose the pull. This also explains the phenomenon of back emf in electric motors, that is, the voltage created by the moving armature which opposes the applied voltage and hence the movement of the armature itself. Lenz law was later extended for more general application by Le Chatelier.

In the same year he also showed that the resistance of a metal increases with temperature.

1833 Scottish chemist Thomas Graham discovers the rate at which a gas diffuses is inversely proportional to the square root of the density of the gas. Now known as Graham's Law of Diffusion. Diffusion however is not confined to gases, it can take place with matter in any state. It may take place through a semi permeable membrane, which allows some, but not all, substances to pass. In solutions, when the liquid solvent passes through the membrane but the solute (dissolved solid) is retained, the diffusion process is called osmosis, a process which is used in many battery designs.

1833 British engineer Isambard Kingdom Brunel brought bad news to his father Marc Isambard Brunel about the "Gaz Engine" on which they had been working for 10 years. After consultations with Humphry Davy in 1923, the elder Brunel concluded that closed cycle hot air engines similar to Stirling's engine could be more fuel efficient than steam engines which lost a significant quantity of water in every cycle, an opinion which was shared by many at the time including Michael Faraday and the British Admiralty. He then began working on a closed cycle engine using "carbonic acid gas" (Carbon dioxide) which was relatively easy to liquefy under pressure. The engine had two reservoirs for the condensed gas which could be alternately heated (vaporised) and cooled by hot and cold water and these two gas sources were used to propel a double acting piston. The idea was patented in 1825 and, joined by the younger Brunel, they made several demonstrators using pressures up to 120 atmospheres. (The hot air engine had originally been conceived to avoid the explosions of high pressure steam boilers). Based on intuition, as were many inventions of the day, a huge amount of money was invested in the project. Eventually the younger Brunel was able to make use of early thermodynamic theories to justify the project. Unfortunately his conclusion in 1833 was that "No sufficient advantage on the score of economy of fuel can be obtained", and the project was abandoned.

1833 Undeterred by the experience of the Brunels (see previous paragraph above), flamboyant, Swedish born, engineer John Ericsson patented in Britain his "caloric engine" a double-acting external combustion hot air engine in which expansion occurs simultaneously on one side of the displacer piston with compression on the other. It was similar to a Stirling engine (patented in 1816) in which the displacer also acts as the power piston but it used an open cycle instead of a closed cycle design.

Ericsson had left his home country for England in 1826 where he entered a design for a railway locomotive in the Rainhill Trials. Although his design "Novelty" was the fastest in the competition, he lost out to Stephenson's Rocket on reliability grounds. Ericsson, an irrepressible self publicist and showman made extravagant claims for his caloric engine which he was not always able to substantiate.

His next ventures were a stream of inventions for naval applications including the ship's screw propeller, a variant of the Archimedes Screw, which he patented in 1836 (though earlier designs by Scottish inventors James Steadman(1816) and Robert Wilson (1827) and others existed but had not been patented). The superior efficiency of the screw propeller was demonstrated by the British Admiralty in 1845 in a competition between two similar sized Navy steam sloops, the Rattler with a screw propeller and the Alecto driven by paddle wheels. On a calm day in the North sea, coupled together stern to stern, they engaged in a "tug-of-war". The Rattler won, pulling the Aleco backwards at a speed of 2.8 knots. It was argued that this was not a fair trial since the Rattler's engines produced 300 horse power compared to only 141 horse power for those of the Alecto, but the Admiralty had already made up its mind and the spectacle gave them the convincing publicity they wanted.

Discredited by his failure to demonstrate the benefits claimed for the caloric engine and failing to interest the British Admiralty in the propeller and after a series of business losses and a spell in a debtors' prison Ericsson left Britain in 1839 for the USA where he continued to work on the caloric engine for 20 years. Though he sold may examples of his caloric engine, interest faded when he was unable to show its superiority to the steam engine. He was however more successful as a naval architect and munitions designer, his most famous design being the USS Monitor the "ironclad" used to great effect by the Union's forces in the American Civil War (1861-1865).

1834 French clockmaker Jean Charles Athanase Peltier discovered that when a current flows through a closed loop made up from two dissimilar metals, heat is transferred from one junction between the metals to the other and one junction heats up while the other cools down. Used as the basis for refrigeration products with no moving parts. This is now known as the Peltier effect and is the reverse of the Seebeck effect discovered 13 years earlier.

1834 French engineer and physicist, Benoît Paul Émile Clapeyron published "Puissance Motrice de la Chaleur" ("The Driving Force of the Heat") in which he developed further Carnot's work on heat engines. He showed how the heat cycle relationship between the volume and pressure of the working fluid as well as the work due to expansion and contraction could be presented and analysed in graphical form.

He also showed that the work done on, or by, a working fluid such as steam can be determined using calculus. Thus:

W = ∫ PdV (integrated between the initial volume Vi and the final volume Vf)

where W is the work done on, or by, the steam, V is its volume and P is its pressure.

1835 German mathematician Carl Friedrich Gauss showed that the total of the electric flux flowing out of a closed surface is proportional to the total electric charge enclosed within that surface. The following relationship applies:

Φ = Q/ε0


Φ is the total flux of the electric field flowing out of the surface.

Q is the total electric charge enclosed by the surface.

ε0 is the electric constant or permittivity of the medium supporting the field.

Now known as Gauss's Law of Electric Fields, it is the electrical field equivalent of Ampère's Law for magnetic fields. It was not published however until 1867 together with Gauss's Law of magnetic fields.

Meanwhile Faraday, working independently, introduced the concept of capacitance with his definition of the dielectric constant ε, being equivalent to Gauss' permittivity.

See also the relevance to Maxwell's Equations.

Gauss also did pioneering work on probability and statistics, defining and characterising the Normal Distribution, now also named the Gaussian Distribution in his honour. It is the theoretical basis of much of today's quality control of which Six Sigma is an example.

Gauss was one of the worlds most gifted and prodigious mathematicians making major contributions to geometry, algebra, statistics, probability theory, differential equations, electromagnetics, and astronomy. Working alone for much of his life Gauss' personal life was, like Ampère's, tragic and complicated. His first wife died early, followed by the death of one of his sons, plunging him into a depression which was not helped by an unhappy second marriage which also ended with the early death of his second wife.

While he was working, when informed that his wife is dying Gauss replied: "Ask her to wait a moment - I am almost done."

1835 Samuel Finley Breese Morse, American artist and professor of the Literature of the Arts of Design in the University of the city of New York and religious bigot with a mandate directly from God, made a career change at the late age of 41 and started work on telegraphy. Undaunted by his lack of knowledge of the principles of electricity, he sought the assistance in developing his ideas, first from a colleague Leonard Gale of the University of New York who pointed out to Morse the need for insulation on the windings of his electromagnets, and then from Joseph Henry who already had a working telegraph system and who explained the need for relays to extend the range of the system. Morse subsequently patented Henry's ideas in his own name. He demonstrated the "first" electric telegraph in 1835 ignoring many prior claims dating as far back as Gray in 1729, Morrison's design of 1753 and Salvá's in 1804 as well as more practical recent inventions by Henry in 1831 and Weber in 1833.

Morse patented his system in 1837 and although it came after the needle telegraphs of Schilling (1832) and that of Cooke and Wheatstone (1837) which was patented earlier the same year as Morse's, Morse's system was simpler and more robust using only a single signalling wire plus a return wire and its use spread very quickly.

Morse subsequently claimed sole authorship for these ideas and also for the relay, another of Henry's inventions ignoring Henry's essential contributions to the system thus creating an irreparable rift with Henry. Similarly, the coding system Morse Code on which single channel telegraphy depends was based on existing technology including Henry's ideas, as well as those of Gauss and Weber, which Morse developed jointly with Albert Vail, Morse's business partner. It was Vail who invented the Morse key and also the printing telegraph which was patented in Morse's name. Their relative contributions are still in dispute. (See also 1841 Bain)

Henry is reported to have said in later life "If I could live my life again, I might have taken out more patents".

The Communications Revolution

Before the advent of the electric telegraph, communications had been limited by the speed of the fastest horse or the fastest ship. It took anything from four to six months to send a message from Britain to Australia and the same time to send a reply back. The telegraph reduced this to minutes, but it didn't just increase the speed of communications, it also dramatically increased the value of the information transmitted. Think of railway signalling which enabled safer movement of trains or military communications which gave commanders intelligence about the enemy's position and enabled rapid deployment of their own assets. Similarly, government or business administrators could monitor the status of remote operations giving them timely opportunity to intervene or to revise their own plans. Think also of commercial networks which could provide time sensitive commercial information to market traders or speculators giving them a competitive advantage.

The electric telegraph also facilitated both the gathering and dissemination of information and brought better understanding of unfamiliar people, places and communities, the first step towards the so called "Global Village".

Providing timely access to information, and the ability to communicate with remote locations transformed news reporting, knowledge of world events, trade, travel, warfare, diplomacy, administration and long range personal and business relationships much more dramatically than today's Internet Revolution.

See also the Transatlantic Cable


For 35 years the battery was a solution looking for a problem. It had been used on a small scale as a laboratory tool providing the energy for electrolysis in the analysis of chemical compounds and the isolation of new elements but it was Morse's electric telegraph which eventually created the deployment of batteries on an industrial scale.

1835 Electric arc welding proposed by James Bowman Lindsay of Dundee. The idea was eventually patented fifty years later by Benardos and Olszewski in 1885.

Lindsay had many bright ideas, including the design for an electric light which he demonstrated in 1836 and several innovations in the field of telegraphy but none of these were ever commercialised.

1836 Demonstration by a British chemist John Frederic Daniell of the Daniell cell, a two electrolyte system using two electrodes immersed in two fluid electrolytes separated by a porous pot.

Volta's simple voltaic cell cannot operate very long because bubbles of hydrogen gas collect at the copper electrode acting as an insulator, reducing or stopping further electron flow. This blockage is called polarisation. Daniell's cell overcomes this problem by using electrolytes which are compatible with the electrodes. Thus the zinc electrode is suspended in an electrolytic solution of zinc sulphate which is contained in the porous pot (Initial designs used sulphuric acid rather than zinc sulphate). The porous pot is in turn immersed in the copper sulphate solution which is contained in a glass jar into which the copper electrode is also suspended. The Daniell cell does not produce gaseous products as a result of galvanic action and copper rather than hydrogen is deposited on the cathode. Daniell's non-polarising battery was thus able to deliver sustained, constant currents, a major improvement on the Voltaic pile.

The Daniell cell chemistry was also available in other configurations which provide superior performance such as the gravity cell or crowfoot cell which eliminated the porous pot.

Daniell's cell was however based on a similar non polarising battery design demonstrated by Becquerel in 1829 which used nitrate electrolytes rather than the sulphate electrolytes used by Daniell. Despite the prior art, Daniell, rather than Becquerel, is remembered as the inventor of the non-polarising cell.

Early galvanic cells were all based on acidic electrolytes and many of these designs produced hydrogen at the cathode causing the cell to become polarised. Two approaches were adopted to solve the polarisation problem. Daniell's solution was a non-polarising cell which did not produce hydrogen. The other alternatives were depolarising cells containing oxidising compounds which absorbed the hydrogen as it was produced and did not allow the build up of bubbles. The Leclanché cell which uses manganese dioxide as a depolariser is an example of this type.

1836 Although it had been known for many years that some chemical processes could be speeded up by the presence of some unrelated chemical agent which was not consumed by the chemical action and that the phenomenon had been used by Döbereiner and others, it was Berzelius who in 1836 introduced the term catalyst and elaborated on the importance of catalysis in chemical reactions.

1836 Electric light from batteries shown at the Paris Opera.

1836 Parisian craftsman Ignace Dubus-Bonnel was granted a patent for the spinning and weaving of glass. His application was supported by a small square of woven fibreglass. The drawn glass was kept malleable by operating in a hot vapour bath and weaving was carried out in a room heated to over 30°C.

1836 Irish priest, scientist, and inventor, Nicholas Joseph Callan, working at Maynooth Theological University in Ireland, invented of the induction coil. He discovered that by interrupting a low current through a small number of turns of thick copper wire making up the primary winding of an induction coil, a very high voltage could be induced across the terminals of a high turns secondary winding of thinner copper wire on the same iron core. Such induction coils are used in the automotive industry to operate the sparking plugs, but in the other industries they are generally known as Ruhmkorff coils.

The importance of Callan's pioneering work was not recognised at his remote institution which had other priorities and he never received recognition for this invention which is now associated with the name of German-born Parisian instrument maker, Heinrich Ruhmkorff. Like all instrument makers, he put his name on every instrument he made and Callan's coil eventually become known as the "Ruhmkorff Coil".

Callan also developed a galvanic cell known as the Maynooth Battery in 1854.

1837 Faraday discovers the concept of dielectric constant, invents the variable capacitor and states the law for calculating the capacitance. The capacitance of a parallel plate capacitor is given by:

C = ε.A/d


C is the capacitance.

A is the area of the two plates.

ε is the permittivity (sometimes called the dielectric constant) of the material between the plates.

d is the separation between the plates

The unit of Capacitance, the Farad, is named in Faraday's honour.

See more about Faraday.

1837 Sixteen years after the principle was demonstrated by Faraday, self taught American blacksmith Thomas Davenport patented the first practical electric motor as "an application of magnetism and electro-magnetism to propelling machinery." Powered by a galvanic battery consisting of a bucket of weak acid containing concentric cylindrical electrodes of dissimilar metals, the motor was a shunt wound, brush commutator device. The magnetic field of the stator was provided by two electromagnets. Two further electromagnets formed the spokes of a wheel which acted as the rotor. The commutator reversed the polarity of the rotor electromagnets as they passed the alternate north and south poles of the stator to create unidirectional rotation. It was granted the first ever patent for an electrical machine.

Davenport's "revolutionary" invention was ahead of its time and it did not bring him the commercial success his efforts deserved. At the time, the lack of suitable batteries or any other source of electrical power to drive the motor inhibited its adoption and his persevering endeavours to improve and promote the motor led him into bankruptcy. His pioneering use of electromagnets in both the stator and the rotor of his machine went largely unnoticed until the idea was reinvented simultaneously by Varley, Siemens and Wheatstone in 1866 for use in their designs for dynamos. It was not until forty years after Davenport's invention that the demand for electric motors eventually took off. Unfortunately Davenport didn't live to see it. He died aged 49 in 1851.

1837Patent granted for a Needle electric telegraph (Two way electric communications) conceived by William Fothergill Cooke, a retired English surgeon of the Madras army studying anatomy at the University of Heidelberg, and refined by physicist Sir Charles Wheatstone of King's College, London. (See 1816 Ronalds) This was claimed to be the first practical battery powered telegraph, however it is very similar to Schilling's design of 1832. An elegant design, instead of using one wire for each letter it used only five signalling wires plus a return wire. By using a combination of the five signalling needles the number of wires could be reduced. When activated, the needles pointed to individual letters on a board. Twenty different letters could be identified by only five wires. There was no provision for sending the letters C, J, Q, U, X and Z. The design was overtaken by the simpler single wire system devised Morse using his coding system of dots and dashes. The relationship between Cooke and Wheatstone eventually ended acrimoniously over a dispute about their respective contributions to the design.

In 1839, Cooke and Wheatstone's telegraph was installed on Brunel's Great Western Railway where, on 1 January 1845, it was successfully used to enable the apprehension of murderer John Tawell fleeing from the scene of his crime on a train travelling from Slough to Paddington. After he boarded the train a telegraph message was sent from Slough, alerting police in London who were able to arrest him on arrival at his destination. It was an event which stirred the public interest in telegraphy which up to that time had been regarded as no more than a scientific curiosity.

Wheatstone claimed many inventions in his lifetime, usually some time after they had been invented by somebody else. Apart from the needle telegraph see the electric clock , punched tape and the dynamo. At least he acknowledged that the Wheatstone Bridge was invented by somebody else.

1837 First commercially available insulated wire made by British haberdasher W. Ettrick who adapted silk wound "millinery" wire, used in hat making, for electrical purposes. The same year William Thomas Henley made a six head wire wrapping machine for manufacturing silk insulated wire and founded Henley Cables.

1837 James W. McGauley of Dublin invented the self acting circuit breaker in which the electric current moved an armature which opened the circuit switching off the current. When the current was removed the armature moved back to its original position and switched on the current once more causing the armature to oscillate and the current to be switched rapidly on and off. The same year American inventor Charles Grafton Page built a similar device which he called a rocking magnetic interrupter. The original purpose of these devices was to provide current pulses to the primary of an induction coil causing repetitive high voltage sparks at the terminals of the secondary winding. This trembler mechanism was subsequently widely used in electric bells, buzzers and vibrators.

1838 Scottish engineer Robert Davidson built a DC electric motor based on iron rotor elements driven by pulses from electromagnets in the stator. It was the first example of what we would now call a switched reluctance motor. The motor comprised two electromagnets one on either side of a wooden rotor and three axial iron bars equally spaced around the periphery of the rotor. The electromagnets were switched on and off in turn by means of a mechanical commutator driven from the rotors.

Davidson used four of these motors to drive a 5 ton electric locomotive on the newly opened Edinburgh/Glasgow railway in 1842 reaching a speed of 4 mph over a distance of one and a half miles.

The vehicle was powered by two large batteries constructed from wooden troughs each with 20 cells containing sulphuric acid in which were suspended zinc and iron electrodes. The motor speed was controlled by lowering or raising the electrodes into and out of the acid. A resin sealant protected the wooden cells from attack by the acid.

Like Davenport's motor, Davidson's motor was also ahead of its time and was not developed into a practical product. The more efficient electromagnetic rotors and stators as pioneered by Davenport, became the norm and the reluctance motor was forgotten. It was however revived in the 1960's when new semiconductor technology made electronic commutation possible and, because of its simplicity, the reluctance motor finds many uses today.

1838 Carl August von Steinheil a German physicist discovers the possibility of using the "earth return" or "ground return" in place of the current return wire for the signal in telegraph circuits thus enabling communications using a single wire.

1839 Steinheil builds the first electric clock.

1839 Welsh lawyer Sir William Robert Grove demonstrates the first Fuel Cell. Attempting to reverse the process of electrolysis by combining hydrogen and oxygen to produce water, he immersed two platinum strips surrounded by closed tubes containing hydrogen and oxygen in an acidic electrolyte. His original fuel cell used dilute sulphuric acid because the reaction depends upon the pH when using an aqueous electrolyte. This first fuel cell became the prototype for the Phosphoric Acid Fuel Cell (PAFC) which has had a longer development period than the other fuel cell technologies.

The same year Grove also demonstrated an improved two electrolyte non-polarising galvanic cell using zinc and sulphuric acid for the anodic reaction and platinum in nitric acid for the cathode. Known as the Grove cell it provided nearly double the voltage of the first Daniell cell. Grove actually developed a rechargeable cell however there were few facilities for recharging at that time and the honour for inventing the secondary cell eventually went to Planté in 1860. Grove's nitric acid cell was the favourite battery of the early American telegraph systems (1840-1860), because it offered high current output. However it was found that the Grove cell discharged poisonous nitric dioxide gas and large telegraph offices were filled with gas from rows of hissing Grove batteries. Consequently, by the time of the American Civil War (1861-1865), Grove's battery was replaced by the Daniell battery.

In later life (1880) Grove became a high court judge.

1839 The Magnetohydrodynamic (MHD) Generator proposed by Michael Faraday.

1839 Prussian engineer Moritz Hermann von Jacobi financed by Czar Nicholas makes first electric powered boat using 128 Grove cells. He also formulated the law known as the Maximum Power Theorem or Jacobi's Law which states: "Maximum power is transferred when the internal resistance of the source equals the resistance of the load". Also known as Load matching.

In 1838 von Jacobi also discovered electroforming by which duplicates could be made by electroplating metal onto a mould of an object, then removing the mould. This galvanic process was used for making duplicate plates for relief or letterpress printing when it was called electrotyping.

1839 Alexandre-Edmund Becquerel discovered the photovoltaic effect when he was only nineteen while experimenting with an electrolytic cell made up of two metal electrodes placed in an electrically conducting solution. He noticed that small currents were generated between the metals on exposure to light and these currents increased with the light intensity. This new source of electricity never had the same impact as the Volta's cells since the currents were small and the phenomenon was largely ignored by the scientific community. 100 years later Becquerel's discovery was recognised as the first known example of a P-N junction. See also Becquerel 1896

1839 Polystyrene isolated from natural resin by German apothecary Eduard Simon however he was not aware of the significance of his discovery which he called Styrol. Its significance as a plastic polymer with a long chain of styrene molecules was recognised by Staudinger in 1922.

1840 James Prescott Joule an English brewer published "On the Production of Heat by Voltaic Electricity" showing that the heat produced by an electric current is proportional to I2R now known as Joule's Law. He also discovered that electrical power generated is proportional to the product of the current and the battery voltage and he established that the various forms of energy, mechanical, electrical, and heat - are basically the same and can be changed, one into another. Thus he formed the basis of the law of Conservation of Energy, now called the First Law of Thermodynamics. See also Joule's work on refrigeration.

1840 Robert Sterling Newall from Dundee patented a wire rope making machine suitable for manufacturing undersea telegraph cables. It was used to make the first successful telegraph cable connecting England and France in 1851 and later with others the first transatlantic telegraph cable. The cable was insulated with gutta-percha, the adhesive resin of the isonandra gutta tree, introduced to Europe in 1842 by Dr. William Montgomerie, a fellow Scot working as a surveyor in the service of the East India Company. Gutta percha was used for 100 years for cable insulation until it was eventually replaced by polyethylene (commonly called polythene) and PVC.

1840 Electroplating, a process discovered by Cruikshank forty years earlier, was re-invented by the Elkingtons of Birmingham and commercialised by Thomas Prime. Articles to be plated were suspended as one electrode in a bath containing an electrolyte of silver or gold dissolved in cyanide. When the voltage was applied to the electrodes the metal was deposited on the suspended article.

1840 Eminent British mathematician and Astronomer Royal, George Biddell Airy, develops a feedback device for continuously manoeuvring a telescope to compensate for the Earth's rotation. Problems with his mechanism led to Airy becoming the first person to discuss instability (hunting or runaway) in closed-loop control systems and the first to analyse them using differential equations. Stability criteria were later established by Maxwell.

Feedback control systems were not new. The list below gives some examples from earlier times:

  • 270 B.C. Greek inventor and barber Ktesibios of Alexandria invented a float regulator to keep the water level in a tank feeding a water clock (the clepsydra - Greek water thief) at a constant depth by controlling the water flow into the tank.
  • 250 A.D. Chinese engineer Ma Chun invented the cybernetic machine, also called the south pointing carriage, models of which can be found in several museums throughout the world. Based on connecting the wheels through a system of differential gears to a pointer, usually in the form of a statuette with an outstretched arm, the pointer always points south no matter how far the carriage has travelled or how many turns it has made. Legend has it that a Chinese general used south pointing chariots to guide his troops against the enemy through a thick fog.
  • 1620 Dutch engineer living in England Cornelius Drebbel invented the thermostat for his stove. It depended on the expansion and contraction of a liquid to move a damper which controlled the air flow to the fire.
  • 1745 Scottish blacksmith and millwright Edmund Lee added a fantail to the moveable cap of the windmill, perpendicular to the main sails, to keep the main sails always pointing into the wind.
  • 1759 English clockmaker John Harrison used a bi-metallic strip to compensate for temperature changes affecting the balance springs in his clocks. As the temperature rises the bi-metallic strip reduces the effective length of the balance spring to compensate for its expansion and change in elasticity.
  • 1787 English carpenter Thomas Mead regulated the speed of rotation of a windmill using the displacement of a centrifugal pendulum to control the effective area of the sails.
  • 1788 James Watt designed the centrifugal flyball governor to control the speed of his steam engines by adjusting the steam inlet valve.

Considering his track record, Airy surprisingly held the post of Astronomer Royal, the highest office in the British civil service, for forty six years. Filled with his own self importance he belittled the work of those whom he considered his social inferiors such as Faraday whose mathematics, in his view, wasn't up to scratch and John Couch Adams who predicted the existence and orbit of the planet Neptune and whom Airy ordered to proceed slowly and re-do his calculations "in a leisurely an dignified manner". Consequently Airy missed its eventual discovery which was scooped by Frenchman Urbain Jean Joseph Le Verrier.

In his role as chief scientific advisor to the government he put a premature end to Babbage's pioneering work on computers with his verdict, "I believe the machine to be useless, and the sooner it is abandoned, the better it will be for all parties", which cut off all government funding for the project.

Airy also advised against the construction of the Crystal Palace to house the Great Exhibition of 1851 because he said the structure would collapse when the salute guns were fired. Despite Airy's objections, it was built anyway and was a great success.

After the Tay Bridge disaster in 1879 when the bridge collapsed into the river during a storm killing all 75 passengers on the train passing over it at the time, the subsequent investigation found that Airy, who who provided the wind loading for designer Thomas Bouch, seriously miscalculated the effect of a Tayside gale on the structure, and that the bridge would have fallen "even if construction had been perfect".

1840 "Steam Electricity", electrostatic discharges produced by the frictional electrification of water droplets, observed by a colliery "Engine Man" near Newcastle in England when probing a steam leak. The phenomenon was investigated by local lawyer, (later to be engineer and arms manufacturer), William Armstrong who constructed what he called a Hydro-Electric Generator using the effect to produce electrostatic charges on demand. It consisted of a boiler insulated from the ground generating a jet of steam from which sparks could be drawn on to an insulated metallic conductor. The conductor became positively charged, while the boiler acquired a negative charge.

See also Kelvin's Thunderstorm for an explanation.

1841 The non-polarising Carbon-Zinc cell, substituting the cheaper carbon for the expensive platinum used in Grove's cell, invented by German chemist Robert Wilhelm Bunsen. His battery found large scale use for powering arc-light and in electroplating.

Bunsen did not invent the eponymous burner for which he is famous. The basic burner was in fact invented by Faraday and improved by Peter Desaga, a technician working for Bunsen at the University of Heidelburg. The improved burner was designed to provide the high temperature flames needed for Bunsen's joint studies of spectroscopy with Kirchhoff and Desaga was smart enough to manufacture and sell the new device under his boss's name.

Bunsen never married. He was a popular teacher who delighted in working with foul smelling chemicals. Early in his career he lost the use of his right eye when an arsenic compound, cacodyl cyanide, with which he was working, exploded.

1841 Scottish clockmaker Alexander Bain invented the first pendulum electric clock. Bain demonstrated his clock to Charles Wheatstone who copied the clock and three months later demonstrated it to the Royal Society claiming it as his own invention. Fortunately, unknown to Wheatstone, Bain had already patented the invention.

Bain also proposed a method of generating electricity to power his clock by means of an earth battery. This consisted of two square plates of zinc and copper, about two feet square, buried deep in the ground a short distance apart forming a battery with the earth acting as the electrolyte. Such an arrangement produces about one volt continuously.

1842 Austrian physicist Christian Andreas Doppler explained that the apparent frequency of waves as experienced by an observer depends on the relative motion between the observer and the source, the wavelength being shorter for an approaching source and longer for a receding source. He used the analogy of a ship sailing into or retreating from the waves to explain his hypothesis, but sceptics were not convinced and so in 1845 he set up an experiment to demonstrate the effect. He arranged for a trumpeter to ride on an open train carriage and, as a reference, for two trumpeters to be positioned (stationed) in a railway station. All three trumpeters were to hold the same note as the train passed through the station. His experiment verified that the pitch of the moving trumpet heard by an fixed observer at the station was higher than the pitch of the stationary trumpets as the train approached the station and lower than the stationary trumpets as the train was leaving the station. Known as the Doppler effect it was shown by Fizeau in 1848 that the effect also applied to light (electromagnetic) waves.

The principle of the Doppler effect is used extensively today in Radar applications and highway speed traps to determine the speed of moving objects by measuring the frequency shift of signals bounced off the speeding vehicles.

1843 Alexander Bain patented a device to scan a two-dimensional surface and send it over wires. Thus, the patent for the fax machine and the first use of scanning to dissect and build up an image was granted 33 years before the patent was given for the telephone. Over a period of five years Bain designed and patented many improvements to the electric telegraph including the use of punched tape (re-invented by Wheatstone and sold to Samuel Morse in 1857) which were widely adopted at the time. Unfortunately he derived no financial benefit from his ideas. His efforts and his money were spent in pursuing patent infringements by Samuel Morse and he retired into a life of obscurity, poverty and hardship.

1843 The first computer program was written by Augusta Ada Byron, Countess of Lovelace, to calculate values of a Bernoulli function. Known as Ada Lovelace she was the beautiful daughter of romantic English poet Lord Byron and wife of the Earl of Lovelace. At the age of 14 she was tutored by famous mathematician Augustus De Morgan at the University of London and became the world's first software engineer. Convinced of her own genius she let everybody know it at every opportunity. She worked as an assistant to Charles Babbage on the development of his "analytical engine" the world's first programmable computer which used punched cards for input and gears to perform the function of the beads of an abacus.

Before Babbage, computing devices were mostly analogue, performing calculation by means of measurement, Babbage's machine however was digital, performing calculation by means of counting. It is claimed that Ada originated the concept of using binary numbers, a practice used in all modern computers, however Babbage's difference engine and more versatile analytical engine were both based on the decimal numbering system. Her notes indicate that she understood and used the concepts of a stored program, as well as looping, indexing, subroutine libraries and conditional jumps, the first use of logic in a machine, however the extent of Babbage's contribution to these thoughts and how much was her own work is not clear. She wrote "The Analytical Engine ... weaves algebraic patterns, just as the Jacquard-loom weaves flowers and leaves." Though her contribution to the technology may be questioned, her charm did wonders for Babbage's PR (although it didn't quite work on Michael Faraday).

Ada however managed to run up considerable gambling debts with her lover John Crosse and as a solution she applied her mathematical prowess to fresh fields developing a winning "system" for betting on horses (proving, incidentally, that genius and common sense don't always go hand-in-hand). Unfortunately, the horses being unaware of their responsibilities, the system didn't win and Ada finished her life as a bankrupt, alienated from her family, addicted to laudanum (opium), dying a painful death from cancer of the cervix at the age of 36, repeating the demise of her father, also an opium addict who died of a fever at same age of 36.

Babbage did not have the financial resources to complete his machines and he appealed to the Prime Minister Robert Peel for help, but after taking advice from the formidable Astronomer Royal Sir George Airy, the request was turned down and his machines were never finished. In 1991 the British Science Museum completed the construction of Babbage's Difference Engine No.2 from Babbage's original drawings with new components and it worked just as he said it would, performing its first test calculation for the public, the powers of seven (y=x7) for the first 100 values.

1843 Sir Charles Wheatstone "found" a description of the Christie's 1833 bridge circuit, now known as the Wheatstone Bridge, and published it via the Royal Society though he never claimed he invented it.

The same year Wheatstone also invented the Rheostat (Greek - "Rheo" Flowing stream) variable resistor.

1843 Patents for the vulcanisation of natural rubber with sulphur to improve its strength, wearing properties and high temperature performance were awarded to Thomas Hancock in England in May 1843 and one month later to Charles Goodyear in the USA. Subsequently patents for hard rubber called vulcanite or ebonite, created by using excess sulphur during vulcanisation, were granted to Hancock in England in 1843 and to Nelson Goodyear (brother of Charles) in the USA in 1851.

Ebonite is a hard, dark and shiny material initially used for jewellery, musical instruments, decorative objects and dental plates (with pink colouring) for nearly 100 years. It is also a good insulator and soon found use in electrical equipment and power distribution panels.

Ebonite was a milestone because it was the first thermosetting material and because it involves modification of a natural material.

Ebonite mouldings were exhibited by both Hancock and Goodyear at the Great Exhibition of 1851.

1843 German founder of modern electro physiology Emil du Bois-Reymond discovered that nerve impulses were a kind of "electrical impulse wave" which propagated at a fixed and relatively slow speed along the nerve fibre. In 1849, using a galvanometer wired to the skin through saline-soaked blotting paper to minimise the contact resistance, he was able to detect minute electrical discharges created by the contraction of the muscles in his arms. Realizing that the skin acted as an insulator in the signal path, he increased the strength of the signals by inducing a blister on each arm, removing the skin and placing the paper electrodes within the wounds. He determined that a stimulus applied to the electropositive surface of the nerve membrane causes a decrease in electrical potential at that point and that this "point of reduced potential", or impulse, travels along the nerve like a wave.

Galvani's theory of animal electricity vindicated at last? See also nerve impulses.

1845 Michael Faraday discovers that the plane of polarisation of a light beam is rotated by a magnetic field. The first experimental evidence that light and magnetism are related. Now called the Magneto-Optic effect or the Faraday effect.

1845 Gustav Robert Kirchhoff a German physicist at the age of 21 announced the laws which allow calculation of the currents, voltages, and resistances of electrical networks. In further studies, based on Kelvin's mathematical representation of the circuit elements, he demonstrated in 1857 that current flows through a conductor at the speed of light.

Between 1855 and 1863 Kirchhoff formed a productive working partnership with Robert Bunsen at the University of Heidelburg where they undertook the first systematic investigation of atomic spectra. They discovered the that the flames of each element had a unique emission and absorption visible light spectrum and founded the science of emission spectroscopy for analysing and identifying chemical substances. They invented the spectroscope which allowed them to analyse not only laboratory samples, but also the Fraunhofer lines in cosmic light spectra and by comparing them with the dark lines in the spectrum of earthly elements they could determine the composition of the Sun and the stars by spectral analysis of the radiation they emit.

These achievements were forty years before the discovery of the electron. A more comprehensive theory taking into account the structure and quantum nature of the atom was eventually developed by Neils Bohr in 1913

After an accident in early life, Kirchhoff spent most of his working life in a wheelchair or on crutches.

1845 Two thousand years after Archimedes explained the mechanical advantage of the compound pulley system, English lawyer William George Armstrong invented the first major enhancement of the original design, a hydraulic jigger for improving the efficiency of dock-side cranes which he demonstrated at Newcastle's "Lit and Phil". It was the converse of Archimedes' block and tackle and used high pressure water from the municipal water supply to operate a hydraulic ram which Bramah had shown to be capable of exerting very high forces. Pulley blocks were attached to the ram's piston and to the case of the ram at the opposite end and a cable or chain was looped around the pulley sheaves and connected to the load. The pressure of the water forced the piston out of the ram thus forcing the pulleys apart, the opposite of a conventional block and tackle which pulls them closer together. Depending on the number of sheaves, the jigger's pulley system magnified the stroke of the ram, increasing the displacement of the lifted load, but reduced the force pulling the load, whereas the basic pulley system magnified the lifting force but reduced the displacement of the lifted load. The load was lowered simply by releasing the water from the ram.

Armstrong's system eliminated the need for costly manual labour to operate the old block and tackle system and provided a smooth lift and greatly increased the speed at which the load could be lifted. It was immediately successful and led to a string of new hydraulic applications including hoists, capstans, turntables, dock gates, rock crushing and even passenger lifts.

Armstrong's interest in hydraulics had been inspired by his role as a lawyer involved in the legal aspects of the provision of municipal water supplies and also by his first view of a waterwheel in action which he encountered while on a fishing trip. As an amateur he had made models of hydraulic systems while still working as a lawyer, but at the age of 37, in 1847 he made a major career change abandoning his Newcastle law practice to start an engineering works at Elswick-on-Tyne, to manufacture hydraulic cranes, where he could work full time on engineering projects.

This was the modest start of Britain's greatest Victorian enterprise.

Armstrong was a great innovator. His next invention, in 1850, was the hydraulic accumulator which was designed to overcome the problem of low, or variable, water pressure for his hydraulic machinery. It provided a controllable high pressure hydraulic source and comprised of a large water-filled cylindrical reservoir with a piston onto which a heavy weight of several tons of concrete or metal could be loaded to increase and maintain the pressure of the water. In 1865 he installed two blast furnaces to manufactture his own castings.

His next venture was to use his considerable engineering skills to revolutionise the design and manufacture of armaments for the British army.

During the Crimean War (1853-1856), he was prompted by reports from the Battle of Inkerman (1854) describing the difficulties caused by the manoeuvrability of the British field guns. It took 150 soldiers and 8 officers three hours to manhandle two smooth bore 18 pounder field guns each weighing 2.1 tons (2134 kg) across one and a half miles (2.4 kms) of rough and muddy, ridged terrain to get them from their siege park to a strategic, elevated defensive position on Home Ridge from which the 100 attacking Russian guns 1300 yards (1200 m) away on Shell Hill would be in range. Meanwhile, until the guns were in place, the British troops, outnumbered by more than 3 to 1, were extremely vulnerable to enemy fire, suffering appalling casualties and loss of life.

Note: Pounders - The size of the guns was specified as the weight in pounds (0.454 kg) of the projectile it fired. After 1864, the capacity of the larger guns was specified as the diameter or calibre of the bore.

The Guns

While the presence of the two 18 pounders at Inkerman was successful in turning the tide of the war, Armstrong felt that it should not be necessary to have a gun weighing over two tons to fire an eighten pound projectile. He believed he could design something much lighter with even better performance by applying the experience he had gained in manufacturing precision hydraulic rams to the development of large field guns. He also recognised that the heavy artillery design, favoured by the military, had not much changed in over 200 years with muzzle loading bronze or cast iron barrels prone to blowing up. Cast iron was fine for making hydraulic rams but it was not suitable for containing the explosive loads found in gun barrels. Attempted breech loading designs had also been too weak and dangerous, failing to withstand the explosion of the charge. On the other hand small arms producers had taken advantage of new materials, skills and technologies developed during the Industrial Revolution to introduce wrought iron rifles and breech loaders firing conical shells and percussion caps replacing smooth bored, cast iron muzzle loading muskets firing round shot.

Artillery development had just not kept pace with small arms development.

What was needed was a scaled up version of the rifle.

Spurred on to come up with a solution by his friend James Rendel, chief civil engineer of the British admiralty who provided practical insight into the issues involved, Armstrong called upon the advice of James Nasmyth and Isambard Kingdom Brunel, who had both shown an interest in weapons development, to help him in this task. The result was a series of breech loading field guns with rifled steel barrels which were lighter, more accurate with greater range than the army's muzzle loading cast iron and bronze cannons, and improved projectiles to use in them. It was a major step in artillery development.

In 1855 the War Office (Now called the Ministry of Defence - How times change.), seeking ideas for improved artillery, received almost 1000 proposals from which Armstrong was selected to produce six prototypes.

Design challenges and solutions included:

  • Construction
  • Conventional field guns or cannon used heavy barrels with thick walls of bronze or cast iron to contain the explosive firing charge and to direct the projectile on its way, but cast iron is brittle with a crystalline structure and has poor tensile strength so the castings had to be very large. Large castings are also susceptible to flaws and cracks. Bronze is softer but that means it wears much more quickly than cast iron. Armstrong's barrels were built up from layers of more flexible and durable wrought iron or steel, each with properties or characteristics optimised for its task. Early designs used an inner tube, or core, forged from solid bars of wrought iron heated to a high temperature and wrapped round a mandrel and forged together to form the lining of the barrel. Subsequently in 1863, mild steel, toughened in oil, was used to manufacture the barrel's core because it had better wear characteristics. The tensile strength needed to contain the explosive charge was obtained by shrinking and welding cylindrical wrought iron rings over the inner tube. The diameter of the rings when cold was slightly less than the diameter of the inner tube, but when heated they expanded and could be slipped over the inner tube. On cooling the interior of the barrel became under compression from the rings shrunk over it. Thicker outer tubes, or more layers, were used near the breech where pressure from the detonation of the charge was greatest. This "Built up" or laminated structure provided a "pre-stressed" barrel. Inward pressure from the outer tube, or tubes, compressed the inner tube, and during firing, counteracted the outward radial forces exerted on the barrel by the explosive charge when the gun was fired. The result was that the barrel, the heaviest part of the gun, could be much smaller and lighter than in previous guns. This construction was later adopted in 1866 by Alfred Krupp in his "ringed gun".

    Added benefits were that the stronger barrel allowed the cannon to withstand more powerful explosions from larger charges of gunpowder so that greater speed and energy could be imparted to the projectile or larger projectiles could be used. The size and weight reduction also enabled much larger guns to be produced.

    The "Build up" construction method was one of the keys to the success of the gun. It's composite structure allowed the gun to be designed to exploit the properties of different materials to create a structure whose strength was greater than the strength of the individual parts.

  • Projectile
  • The second major factor contributing to the gun's success was the design of the projectile. It was well known that using an elongated shell with a conical tip rather than round shot would increase the range since the wind resistance encountered by a projectile increases with its cross-sectional area. For the same weight an elongated shell will have a lower cross-section and hence lower wind resistance. To provide directional stability and prevent the shell tumbling end over end or deviating from its course the gun must impart a spin to the shell as it leaves the gun and this is done by rifling the barrel.

    Rifling also placed requirements on the projectiles. They must be a tight fit in the barrel and engage with the rifled grooves. For this reason shells with a soft metal casing such as lead are required. Armstrong's shells were hollow, containing an explosive charge which was not unusual for the period, but a soft metal hollow shell would be prone to collapsing due to the explosive forces during firing.

    The shells were therefore made from cast iron with a thin deformable lead coating so that its diameter was slightly more than the calibre of the gun. When the gun was fired the lead engaged, and was crushed, in the barrel's rifling grooves imparting the necessary spin to the shell. This tight fit had the added advantage of minimising the windage losses (See below) in the gun barrel thus increasing the range.

  • Propellant Charge
  • The gunpowder propellant charge used to accelerate the shell was contained in a cloth bag which was loaded directly behind the projectile.

  • Windage
  • Windage is the narrow gap between a gun's bore and the projectile's diameter which was necessary in smooth bore, muzzle loading guns to allow for crude manufacturing tolerances of the cast iron projectiles and to allow the projectile to be rammed down the length of the barrel on loading. Windage also referred to the amount of hot propellant gas that escaped around the loosely fitting projectile on firing. This effect reduced the volume and pressure of the gas accelerating the projectile, seriously reducing the gun's range. Traditional cannon firing spherical cannon balls were particularly wasteful.

    On the positive side, the flash of the escaping propellant gas passing around the shell provided a self-igniting fuse when used with explosive cells, avoiding the need to light the fuse before loading the shell.

    Armstrong's tight fitting rifled shells however did not suffer from windage. All of the propellant gas generated by the explosive charge was applied to the projectile increasing the range of the gun or allowing smaller firing charges to be used. It also meant that, without the hot flash, another method of initiating the shell's fuse had to be found. (See below).

  • Rifling
  • The method of rifling was Armstrong's third major innovation. A projectile's range, accuracy and stability are improved by spinning it around its axis as it emerges from the muzzle so that the gyroscopic forces due to the spin stabilise its orientation and keep it on track during its flight to the target. This is achieved by machining helical grooves, called rifling, along the length of the gun barrel to impart spin to the projectile as it emerges from the muzzle. This puts conflicting demands on the material used for the gun barrel. It must be very hard to resist the wear caused by friction with the projectiles used. This would suggest the use of cast iron, but because cast iron is very hard, it is difficult to machine. Its tensile strength is also too low, unless the casting is very thick, to absorb the pressures of the explosive charge and is brittle and prone to cracking. While bronze castings are much easier to machine, they are too soft and the rifling would soon be damaged. It was wrought iron which made rifling possible - being harder than bronze and having higher tensile strength than cast iron, it made rifled barrels more practical.

    Rifling also affected the design of the projectiles which had to be compatible with the rifling in the barrel.

    See more about Whitworth and alternative rifling.

  • Breech Loading
  • Breech loading was necessary because the alternative of loading a rifled gun through the muzzle was very difficult, but it also had other advantages, the main one being a faster rate of fire. Loading the gun from the rear leaves the crew less exposed to enemy fire and also allows smaller gun emplacements or turrets.

    These advantages were well known at the time but existing designs were unreliable, unsafe and unpopular. The bore of Armstrong's gun was closed by a metal block or "vent piece" which was dropped into a slot and kept in place by a large screw. It was an improvement on current practice but still not perfect and in a few cases vent pieces had been ejected at high speed from the breech.

  • Muzzle Loading
  • Because of the extremely high explosive forces encountered in high calibre guns and the greater consequences of a failure, Armstrong did not consider the safety margin of the breech loading mechanism to be sufficient for guns larger than his 110 pounders. He therefore reverted to muzzle loading for higher calibre guns.

  • Fuses
  • With the elimination of windage, Armstrong had to find a new safe method of self igniting the fuses in his explosive shells. He designed a variable delay fuse, initiated on the shell's exit from the barrel and timed to explode before the shell hit the target to cause fragmentation damage. The shell contained a suspended hammer which was released by the shock of firing to ignite the primer, initiating the timing sequence. Shells designed to explode on impact to increase the blast damage to, or the penetration of, the target caused by the shell used a percussion fuse in the nose of the shell to initiate the explosion.

  • Materials
  • Armstrong's gun, like all guns, was subject to extreme tensile, compression, shock, vibration and abrasive forces as well as temperature extremes and the selection of optimum materials was important for their success. Manufacturing processes included steel making, casting, welding, forging and precision machining. The behaviour of the explosive charges used had to be controlled.

    In the 1850s, process control was rudimentary and the quality of the materials used was often inconsistent. Metallurgy was in its infancy and there was very little, if any, published data about the strength of materials.

    Armstrong spent months testing different materials to understand the factors influencing their performance to enable him to optimise their use and to ensure they were fit for purpose. He even tested a variety of chemical additives to the explosive charges to ensure a safe, optimum burn rate of the charge.

Armstrong Guns - Performance

In 1855 the first trial gun delivered to the War Office for testing was a 3 pounder firing cylindrical shaped lead shot and weighing 560 pounds. It was disparaged by the War Office's Ordnance Committee as being too small for use on the battlefield though they conceded that it had improved accuracy, range and power. Undeterred, Armstrong bored out the barrel to carry a 5 pound cast iron shot coated with lead, following up the next year with an 18 pounder.

In 1859 after four more years of discussions with sceptical military men and unfriendly rivalry from Joseph Whitworth, a competing arms manufacturer, new tests of larger guns, under service conditions, were arranged. Armstrong's 18 pounders demonstrated three times the range and 57 times better accuracy at the same distance than the Army's 18 pounders. The reloading time was substantially reduced and their higher speed projectiles carried more destructive power. Furthermore with a weight of only 0.6 tons (610 kg) they were over 70% lighter than the cumbersome 18 pounders used at Inkerman.

The Army officers present were astonished and Armstrong's gun was rapidly approved by the War Office, going into service the same year.

Armstrong suddenly became a national hero. He was made Engineer of Rifled Ordnance to the War Department and given a large order for guns.

The War Office recognised the importance of Armstrong's gun technology but were concerned that the technology could be acquired by the foreign armies. Armstrong in turn was worried that the War Office would eventually transfer the production of his gun to its own munitions factory at Woolwich Arsenal. Between them, they negotiated a long term contract which protected Armstrong's Elswick gun making business and in return Armstrong gave his 11 patents for ordnance and projectiles to the government. In recognition of this gesture he was awarded a knighthood. As Armstrong had feared, procuction at Woolwich was ramped up using using his patents and government contracts for guns from Elswick were severely cut back. Fotunately he was able to more than make up for the loss by selling overseas.

He went on to produce breech loading guns in various sizes ranging from 6 pounders to 110 pounders weighing 4 tons but for larger sizes (150, 300 and 600 pounders) he reverted to muzzle loading, considering breech loading to be too risky and dangerous.

In 1887 he produced a "Monster" gun weighing 111 tons (112,000 kg) with a calibre of 16.25 inches (413 mm) and a total length of 43ft 8in (13.3 m). Designed for use on warships it had an effective range of 8 miles (12.9 km). Its 1800 pound (816 kg) shells emerged from the muzzle at a speed of 2020 feet per second (2,217 km/h), and could penetrate wrought iron to a depth of 30.6 inches (777 mm) at a distance of 1000 yards (914 m).

The Ships

In 1867 Armstrong's company expanded into fitting out warships, a logical progression since the navy already used Armstrong's hydraulics for handling their big guns. He negotiated a venture with the local shipbuilding firm of Mitchell & Swan who would make warships at their Walker yard 6 miles down river, while Armstrong would provide the guns.

Unfortunately there was low bridge across river between the two factories blocking the passage of large ships. He solved the problem by designing a Swing Bridge, operated by his hydraulic rams, rotating on a pivot at the centre of the river to let the ships through. The bridge was opened in 1873 and is still in operation today.

In 1894 Armstrong also designed the hydraulic mechanism that operated London's Tower Bridge.

In 1882 Mitchell & Swan merged with Armstrong's company to form Armstrong, Mitchell & Co. and a new shipyard specialising in warship production was built at Elswick next to the armaments works, together with a new steelworks with two Siemens open hearth furnaces. When it was completed the Elswick works covered 50 acres extending for over a mile along the north bank of the River Tyne and employed 11,000 rising to 13,000 during peak loads. It was the only shipyard which could build a battleship including all its armaments. Armstrong also opened a manufacturing plant in Italy. Between 1881 and 1897, 42 warships were produced at the Elswick works.

By 1897 Armstrong, Mitchell purchased the engineering firm of their old rival Joseph Whitworth who had died 10 years earlier. By now Whitworth's employed 2000 men, compared with Armstrong Mitchell's 20,000 and had added toughened steel armour plate and gun mounting mechanisms to their product line which neatly complemented Armstrong's output. Armstrong Whitworth became one of the world's greatest manufacturing companies.

Armstrong's weapons and ships were bought by armies and navies all over the world from Russia, China and Japan to Argentina, Chile and the United States, where he supplied both armies in the American Civil War (1861-1865), bringing him immense wealth.

Though Armstrong died in 1900, his company still prospered and supplied vital armaments during World War I including 13,000 big guns, 100 tanks, 47 warships, 140 converted merchant ships, 1,000 aeroplanes, 3 airships, 14,500,000 shells, 18,500,fuses and 21,000.000 cartridges. What would Europe look like today if had not had Armstrong's technology to challenge Germany's mighty Krupp?

Cragside, Armstrong's home in Northumberland, was a showcase for his ingenuity. In 1878 it was the world's first private dwelling to be fitted with electric lights (apart from the homes of the various inventors of rival electric lights). Initially it was lit by carbon arc lamps powered by a hydroelectric generating system of his own design, also a world's first. Electric power was supplied by a 4.5kW, 90 Volt Siemens dynamo, belt driven by a 6hp Vortex inward flow reaction turbine locally manufactured to a design by James Thomson, elder brother of Lord Kelvin. The turbine was fed with water from an artificial lake created for the purpose in the grounds of Armstrong's estate. The power plant was located 1320m (almost a mile) from the house and current was transmitted through bare copper wire with a round trip of 2.6km. In 1880, the carbon arc lamps were replaced by 45 incandescent lamps, recently invented by his friend Joseph Swan. Then four years later, in the first of many upgrades, the generating capacity was increased to power 92 lights using a Compton dynamo delivering 90 Amps at 110 Volts, driven by a 24hp (17.9 kW) Vortex turbine.

Other domestic gadgets included central heating by means of warm air ducted to the rooms, an electric bell system to summon staff to their stations, a hydraulic lift to provide access to the upper rooms and a water powered roasting spit in the kitchen.

Armstrong was a hard task master but also a generous philanthropist funding many public works in his native Newcastle.

When he died aged ninety in 1900 he was worth £1,400,000 (£160 million in today's money).

1846 The Smithsonian Institution established in the USA, "for the increase and diffusion of knowledge among men" with a large endowment from English chemist and mineralogist, James Smithson, in neat symmetry with the founding of the Royal Institution in England by the American, Count Rumford. Joseph Henry was chosen as the Smithsonian's first distinguished Secretary. Smithson never visited the United States but after he died his remains were brought there for burial.

1846 From his experiments on magneto optics Faraday discovered that some substances such as heavy glass and Bismuth are repelled rather than attracted by magnets and named the phenomenon diamagnetism. Using the analogy with dielectrics and conductors he made the distinction between diamagnetics - "poor conductors of magnetic force" and paramagnetics - "good conductors of magnetic force".

1846 The birth place of the modern oil industry was Baku in Azerbaijan, then part of the Soviet Union, where the first "modern" oil well was drilled in 1846 by local mining engineer V. Semyonov. It was followed by others in Bobrka in Poland (1854), Bucharest in Romania (1857), Lambton County, in Ontario, Canada (1858) and Titusville in the USA (1859). Except for the 1857 Canadian well which was originally dug by hand, all of these so called "modern" wells used the same percussion drilling techniques, also called cable tool drilling, that the Han Chinese had pioneered in their oil fields 2000 years before.

In 1898, the Russian oil industry exceeded the U.S. oil production level and by 1901, Baku produced more than half of the world's oil.

Though it was not the first, the Titusville oil well drilled by Edwin Laurentine Drake in 1859 is usually considered to be the West's first commercially viable source of oil.

Drake's is a sad story. An ex railroad conductor with no engineering or drilling experience he had retired from the railroad at the age of 38 due to ill health. Around the same time, the Pennsylvania Rock Oil Company had been formed to exploit oil deposits which were seeping from land in various locations, particularly around Titusville in Pennsylvania, but financial difficulties caused the break up of the company which re-emerged with a low capital base as The Seneca Oil Company.

In 1858 Drake invested in Seneca Oil and he was hired by them with a salary of $1,000 per year. Giving him the nickname of "Colonel" to impress the local residents, Seneca Oil sent him to Titusville to investigate the oil deposits there. He set about building a drilling rig based on traditional percussion drilling methods but using a steam engine for repetitively raising the heavy drill bit. He devised improvements for drilling through the bedrock, housing the bit in an iron pipe to prevent the borehole from collapsing but the work took longer than expected. When Seneca Oil, having invested $2,000 in what appeared to be a dry hole, refused to provide any more capital to purchase essential equipment, Drake used his own money to fund the work. After many difficulties and scorn from the locals he struck oil in August the following year at a depth of 69½ feet (21 metres). Almost immediately Drake's methods, which he failed to patent, were copied by others in the vicinity and America's oil boom was launched.

Unfortunately Seneca Oil did not pay Drake's salary for more than two years, eventually paying him off in June 1860 with a payment of $2,167. By 1862 much more productive wells had come on stream causing the price of oil to drop and Seneca Oil with its original low capacity wells went out of business. The man who had made countless people very rich died in poverty, an invalid, confined to a wheelchair at the age of 61.

1847 Ignoring the difficulties encountered with previous experimental Atmospheric Railways including the Croydon railway by built by William Cubitt in 1846, as well as warnings from experienced engineers such as Daniel Gooch and Robert Stephenson, in 1847 Isambard Kingdom Brunel launched his his own atmospheric railway connecting Exeter with Newton Abbot in Devon, a distance of 20 miles (32 km).

This system did not use heavy locomotives on the track to pull the carriages. Instead the carriages were pulled along by a piston moving in a pipe laid between the tracks. A large stationary engine ahead of the train pumped air out of the pipe and the pressure differential between the partial vacuum in front of the piston and the atmospheric pressure behind it caused the piston to move along the pipe. The piston was connected to the floor of the carriage by means of a plate which slid in a slot at the top of the pipe and the vacuum was maintained by airtight leather flaps, rivetted to the pipe, which opened as the plate passed through and closed again after it passed. Brunel's railway used 15 inch (381 mm) pipes on the level sections, and 22 inch (559 mm) pipes for the steeper gradients. Pumping stations were situated every three miles along the line and trains could run at 20 miles per hour (32 km/h).

The advantages of this system were that there were no heavy locomotives on the track, the stationary engines were more efficient, more reliable and easier to maintain, there were fewer problems with traction on the gradients, and the passengers would not be subject to the noise and smell of the steam engine.

Disadvantages were mainly associated with the seal around the piston and, more importantly, maintaining the vacuum seal in the slot which was its Achilles heal. Apart from wear and tear, the leather flaps were attacked by vermin and damaged by frost in the winter. Various lubricants were tried to keep the leather supple including cod oil, soap, beeswax and tallow but the problems with the seals remained. Less serious problems were the inconvenience of decoupling the carriages from the piston at the end of each section and reconnecting them to the piston in the next section. Furthermore the trains could not be run in reverse. Running costs however were another major problem. It was calculated that Brunel's atmospheric traction cost 3s 1d per mile (£0.10/km), compared to 1s 4d (£0.04/km) for conventional steam power.

In view of these insurmountable difficulties the project was abandoned in 1848 after only one year and the line returned to conventional locomotive haulage. The shareholders in the system had lost £500,000.

1848 Scottish physicist, born in Belfast, William Thomson (later elevated to "Lord Kelvin") established the basis for an absolute temperature scale. Starting from the experimental results of Charles and Gay Lussac, Kelvin showed also that there is an absolute zero of temperature which is -273°C. The absolute temperature scale is named the Kelvin scale in his honour and -273°C is called 0°K or absolute zero.

Kelvin was an infant prodigy in mathematics, entering Glasgow University at the age of ten, he started the undergraduate syllabus when he was only fourteen and published his first scholarly papers, correcting errors in the works of both Fourier and Fourier's critics, when he was only sixteen. Fourier remained an inspiration to him throughout his early years. Kelvin always sought practical analogies to explain his theories and published over 600 scientific papers on mathematics, thermodynamics, electromagnetics, telecommunications, hydrodynamics, oceanography and instrumentation and he filed 70 patents. He is remembered for his work on the Transatlantic Telegraph Cable but he initially gained fame by estimating the age of the Earth from a knowledge of its cooling rate at over 100 million years (later revised and broadened from 20 to 400 million years) in contradiction of the prevailing religious, creationist view of the World. Despite this he maintained a strong and simple Christian faith throughout his life and engaged in a long running public disagreement with Charles Darwin, remaining "on the side of the angels", claiming that, according to his calculations, the age of the Earth was too short for Darwin's evolutionary changes to have taken place. (Current estimates give the age of the Earth as 4.6 billion years taking into account the heating effect of radioactivity of the Earth's core, something of which Kelvin could not have been aware). He remained actively involved in scientific work until he was 75 but in later life he found it difficult to accept Maxwell's theories, for which he himself had been the Genesis, and the concept of radioactivity.

According to C. Watson, Kelvin's biographer, "During the first half of Thomson's career he seemed incapable of being wrong while during the second half of his career he seemed incapable of being right."

1849 President Abraham Lincoln was granted a U.S. patent number 6469 for a device for lifting riverboats over shoals [shallow water], the only U.S. president ever to have been awarded a patent. Part of his application read, "Be it known that I, Abraham Lincoln, of Springfield, in the county of Sangamon, in the state of Illinois, have invented a new and improved manner of combining adjustable buoyant air chambers with a steam boat or other vessel for the purpose of enabling their draught of water to be readily lessened to enable them to pass over [sand] bars, or through shallow water, without discharging their cargoes...".

The device was never manufactured.

1849 The first accurate terrestrial measurement of the speed of light was made by French physicist Armand Hippolyte Louis Fizeau. Previous measurements had been based on observations of the movement of planets and moons by Danish astronomer Ole Christensen Rømer (1676), English astronomer James Bradley (1728) and others. Fizeau directed a beam of light through the gaps in a rotating cog wheel to a mirror several miles away and observed the reflection of the pulses of light coming back through gaps in the wheel. Depending on the speed of rotation of the wheel, the returning light would either pass though the gap or be blocked by a tooth. The speed of light could be calculated from the distance to the mirror, the number of teeth on the wheel and its rate of rotation. He determined the speed of light to be 186,000 miles per second or 300,000,000 metres per second.

Also known as Einstein's constant, the speed of light is represented by the symbol c for "celeritas" (Latin - "speed").

Fizeau also showed that the Doppler effect also applied to lightwaves.

1849 The Bourdon tube pressure gauge was patented by French engineer Eugene Bourdon. It is still one of the most widely used instruments for measuring the pressure of liquids and gases of all kinds, including steam, water, and air up to pressures of 100,000 pounds per square inch as well as pressures below atmospheric. It consists of a "C" shaped or spiral curved tube sealed at one end which tends to straighten out when a pressurised fluid is admitted into it. The displacement of the end of the tube is used to move a pointer or other indicator.

1850 Prussian born theoretical physicist Rudolf Julius Emmanuel Clausius publishes his seminal paper "On the Mechanical Theory of Heat" establishing the study of Thermodynamics and outlining the basis of the Second Law. In 1865 Clausius defined the notion of entropy.

1850 The trembler electric bell invented by John Mirand.

1851 In his treatise "On the Dynamical Theory of Heat." Kelvin formally states the Second Law of Thermodynamics, that "Heat does not spontaneously flow from a colder body to a hotter". It was later restated in the form "In a closed system entropy can only increase", recognising the concept of entropy proposed by Clausius in 1865.

1851 Joseph Whitworth, one of Britain's great Victorian engineers first came to the public's attention with his exhibits of precision engineering at the Great Exhibition of 1851 in London. They included his bench micrometer based on precision flat planes and a measuring screw which he claimed (possibly somewhat dubiously) could measure to an accuracy of one millionth of an inch (0.000001 in ≈ 0.025 µm). He also showed the BSW screw thread standards named after him and a range of precision machine tools he had built. These exhibits provided the foundations necessary for mechanisation, for the manufacturing interchangeable parts and for mass production.


In the early nineteenth century machines were very basic and often powered by hand or by a foot treadle. There were no standard measures, parts would have to be individually engineered and each workshop had its own techniques and references. Nuts and bolts were hand made and expensive. They would be made to fit as a pair and were not interchangeable. In 1830 a good workman could typically achieve an accuracy of one sixteenth of an inch but that was all changed by Joseph Whitworth who raised the standards of accuracy in manufacturing to a degree previously unknown, revolutionising the manufacturing of mechanical parts and the production of armaments.

Whitworth, born in 1903, was fostered out at the age of 11 after the death of his mother. He received only elementary education and on leaving school he became an indentured apprentice for four years in a cotton mill after which he he worked for another four years as a mechanic in a factory in Manchester. At the age of 22 he moved to London where he managed to find a job working for Henry Maudslay, inventor of the screw-cutting lathe. His experience there was invaluable. Maudslay set the highest standards of precision and workmanship which were readily assimilated by Whitworth.

In 1828 Whitworth left Maudslay's to work at Charles Holtzapffel's machine shop, moving on again in 1830 to join Joseph Clement, another eminent London toolmaker, where amongst other things he worked on Charles Babbage's difference engine until the government funding was withdrawn in 1832.

Whitworth's Machines and Tools

In 1833 he returned to Manchester and opened his own business developing and manufacturing machine tools for steam engines, for the cotton and textile industries and for the fledgling railway system. They included precision tools for turning, shaping, milling, slotting, gear cutting and drilling and Whitworth became renowned for his high standards of accuracy and workmanship.

In 1834 he filed his first independent patent for improved precision screw cutting machinery which speeded up the manufacturing of nuts and bolts, dramatically reducing the costs, while at the same time improving the accuracy and thus enabling interchangeable parts.

He was passionate about setting high measurement and workmanship standards and took the accuracy of Maudslay's reference surface planes to another level by scraping rather than grinding, publishing the results in 1840 in his first paper "Plane Metallic Surfaces or True Planes". Applications of his true planes and measurement systems were shown at the 1851 Great Exhibition to great acclaim.

In 1841 Whitworth produced a paper recommending a rationalised universal system of screw threads. The angle between the V groove of the thread was a standard 55 degrees and the depth and pitch of the thread were in constant proportion. The number of threads per inch was specified for different diameters screw diameters. The proposal became known at the Whitworth thread. Its adoption by the Woolwich Arsenal, the government's main munitions factory, quickly followed by the railway companies, who until then had all used their own screw thread designs, led to its widespread acceptance and by 1858 it was in universal use in Britain and several other countries, though it was not formally approved by the British Board of Trade as a national standard until 1880.

The USA adopted a different standard based upon a 60 degree thread form proposed by William Sellers in 1864 and these were subsequently developed into the American Standard Coarse Series (NC) and the Fine Series (NF).

After 1945, the requirements of international trade created the need for international, rather than national, standards. This need was reinforced by problems experienced during World War II, caused by the lack of interoperability between the equipment of the different allied armies. In response, international standards for American Unified and ISO Metric threads were defined and after 1948 the British Standard Whitworth BSW thread standard was gradually replaced.

BSW standards are however still widely used today for some applications, though not in the US, such as the British Standard Pipe thread and also in some photographic camera fittings.

In 1849 Whitworth lodged 15 patents for machine tools.

The Whitworth Rifle

Whitworth's exhibits at the Great Exhibition had earned him the reputation as a manufacturer of machines of unrivaled quality and precision. Two years later as Britain was becoming concerned about the possibility of war in Crimea his talents were called upon by the government's War Office who asked him to provide equipment for the mass production of their standard issue Enfield Rifle. This was based on the French, muzzle loading Minié rifle design and produced at the government's Royal Small Arms Factory at Enfield near London. Whitworth was cautious, never having made a firearm before. The Enfield was notoriously inaccurate and unreliable. Why would he want to be involved in making such a questionable product? He suggested instead that he would carry out research into a new weapon to replace it. This offer was turned down, but by 1854, when Britain had entered the war, Whitworth was once more approached by the War Office. In response he proposed to undertake a series of trials to analyse the factors contributing to the rifle's performance and to determine the best manufacturing methods before production could start. This would take about three years - one year to construct an experimental shooting gallery suitable for housing the experiments and two years to carry them out. There was little support for this approach from military officers who believed that battles were won with heavy artillery, not with rifles. The project was eventually approved after Whitworth pointed out that he would use the experiments on small arms to better understand the principles involved, particularly rifling, then this technology could be scaled up for heavy artillery.

The main problem to be solved centred around the rifle barrel. In 1854 no rifle barrel had ever been bored from a solid metal rod and there were no suitable tools for doing it. It was not possible to drill a deep narrow bore since the available drill bits deviated uncontrollably from the desired path. Drilling from both ends of the rod was no better as there was no guarantee that the two bores would meet in line. Consequently, all small arms barrels were produced by blacksmiths swaging a wrought iron strip lengthways around a cylindrical metal rod, called a mandrel, with a diameter matching the desired bore of the gun barrel. The strip was heated until white hot then hammered by hand, using a 5 pound (2 kg) hammer, into a curved swage block mounted on an anvil, to form a long "U" shaped channel. Then after further heating, to maintain the white hot temperature, the "U" shaped channel was gradually curved around a mandrel by further hammering until the opposite edges met. Continued hammering in the presence of a flux was required to fuse the edges together to form a seamless, solid tube. This was highly labour intensive and required great skill from the blacksmith. With such a primitive process, it was difficult to control the accuracy of the results and individual barrels had wide variations in the diameter of the bore and the straightness of barrel. It was at least possible to clean out the bore using a plate or spade drill but this did little to improve the accuracy.

This was the method used to manufacture the Enfield rifle barrels. A "generous" tolerance was permitted on the bore diameter to allow for muzzle loading. Even if the barrel was straight, at the low side of the tolerance it was possible that the projectiles jammed in the bore. Using the traditional ram rod to push the a lead projectile down the bore damaged its point destroying its aerodynamic shape. At the high side of the bore tolerance the projectile would be loose in the bore as it exited so that there was no control over its direction.

Whitworth's next challenge was the rifling. It was already known that rifling the gun barrel's bore provided spin stabilisation which improved a projectile's range, accuracy and stability. In 1835 English gun maker William Greener developed a self expanding bullet and later mechanical fit bullets for this purpose. His muzzle-loading shotguns and rifles had been demonstrated at the Great Exhibition where he was awarded a gold medal.

  • Self Expansion Projectiles
  • The Greener bullet was designed to fit easily into the muzzle for easy loading, but to expand due to the explosive charge when fired so that it would engage with the rifling while at the same time reducing the windage, the wasted energy of the charge leaking past the bullet. The reduction in windage allowed more of the energy of the explosive charge to be transferred to the bullet, however some of this gain was lost due to the increased friction between the bullet and the barrel due to the rifling. Greener's bullet was a two part projectile with a hollow base fitted with a plug which forced the base of the bullet to expand on firing.

    The Enfield rifle was based on Greener's ideas. It used a version of the Minié ball invented by French Army officer Claude-Étienne Minié in 1846. It was a conical bullet with lead skirting containing three exterior grease-filled grooves around its circumference and a conical hollow in its base containing an iron plug which expanded the bullet on firing.

    William Armstrong's big guns also used a variation on this design.

  • Mechanical Fit Projectiles
  • Soft lead coated bullets were prone to fouling up the gun barrels and Greener proposed mechanical fit bullets to overcome this. This enabled the use of harder, more destructive, steel bullets and shells, however it needed tighter tolerances and much more precise dimensional control of the barrel rifling and of the bullet shape to avoid the possibility of jamming and to keep the windage losses to a minimum. Few gun makers were able to deliver this accuracy on a repeatable basis. This was the route taken by Whitworth. Instead of machining narrow slots in the barrel to guide the oversize bullets, he chose to make the cross section of the bore hexagonal in shape with the spin being imparted by a helical (often incorrectly called "spiral") twist to the bore along the length of the barrel. The corresponding bullets would also need to have a hexagonal cross section fitting snugly into the barrel.

In 1854 Whitworth began his test programme to find ways of designing a superior rifle which solved the above problems. The first task was to build the shooting range. It was a brick tunnel 500 yards (457 m) long 20 feet (6 m) high with a tiled roof and a level concrete base. This was not ready until the following year, after which tests began.

Like all his work, Whitworth's comprehensive test programme was meticulous and methodical. Rather than producing a series of trial prototypes as was typical at the time, he investigated and measured every aspect of gun design changing one element at a time to determine its affect on performance. This included, the weight and composition of the explosive charge, the length, bore and weight of the barrel, the weight and shape of the bullets, self expansion and mechanical fit bullets, different types of rifling and spiral turn rates and the manufacturing methods and tolerances needed to produce the parts.

For his initial test sample of hexagonal rifling, he used six thick metal strips pressed together under great heat to form a hexagonal tube held together by external hoops. The desired helicality (usually called "spirality") was achieved by heating and twisting the tube. For ballistics testing he also had to improvise since no suitable high speed test equipment was available. To track the trajectory of the projectiles he suspended tissue paper screens every 30 yards to record their path and to determine the spin behaviour he used bags full of bran to catch bullets in mid flight.

The tests showed that the friction of expansion bullets caused an efficiency loss of 20% to 21% in the barrel whereas mechanical fit bullets in a hexagonal barrel suffered only a comparable loss of 2% to 3%. In summary he demonstrated that using polygonal rifling with a fast helical turn rate and mechanical fit bullets gave more accuracy, longer range, higher impact energy with a lower explosive weight than current self expansion bullets.

For production, in 1857 Whitworth devised a more accurate method of deep boring rifle barrels from solid. Up till that time the only drill bits available were spade or plate bits welded to a narrow rod to allow the swarf to pass. They had poor axial location, tending to wander, and poor swarf removal. He solved both problems simultaneously by extending the length of the spade and giving it a twist over its whole length which improved its rigidity and helped remove the swarf. This was the first simple twist drill.

In 1861 a more practical twist drill bit which we would recognise today was invented by American engineer Steven A. Morse. It used a more substantial steel rod, with a diameter equal to the hole to be bored to avoid the problem of wandering. Early Morse twist drills were made by cutting straight parallel grooves on opposite sides, along the length of the rod, then heating and twisting it to form the helical grooves. The following year another American engineer, Joseph R. Brown, invented the first fully universal milling machine which was used to cut the helical flutes in twist drills.

After boring, an adjustable broach was passed down the bore to cut the necessary hexagonal rifling in the bore.

Whitworth's first prototype rifle incorporating all his new found knowledge and his elongated hexagonal bullets were ready in 1857 as planned, but this was one year after the Crimean war had ended.


Trials were carried out the same year to compare the Whitworth and Enfield rifles and the performance of the Whitworth rifle was superior in every way. It was able to hit the target at a range of 2,000 yards, where the Enfield was only able to hit the same target at a range of 1,400 yards. It was also lighter, it used a smaller charge and permitted a faster reload rate than the Enfield and it was also the first rifle with the capability to shoot a bullet through a 0.6 inch (15 mm) wrought iron plate (at a reduced range of 20 yards). This accuracy was also demonstrated at the British National Rifle Association meeting in 1860 when Queen Victoria fired the first shot from a Whitworth rifle mounted on a fixed rest hitting the bullseye of a target set up 400 yards away.

Despite these successes the British government rejected the design because the calibre of the Whitworth barrel was smaller and more prone to fouling than the Enfield, and the Whitworth rifle also cost approximately four times as much to manufacture. Nevertheless, Whitworth was able to sell the rifle to others including the French army, and also to the Confederate army during the American Civil War (1861-1865) where it was highly valued for its range and accuracy. Between 1857 and 1865 the company sold 13,400 rifles.

Whitworth Artillery

Starting in 1859 Whitworth took the design principles he had learned about rifles and applied them to the design of heavy artillery. At the same time he developed a new breech loading mechanism to complement the design. Trials over the next three years indicated that cast iron or hard steel gun barrels had a tendency to fracture or explode when they were unsound, whereas gun barrels made from ductile steel would more likely be deformed and less dangerous. Casting flawless ductile steel however was very difficult mainly due to the presence of tiny voids or air pockets within the ingot. Whitworth's solution for improving the bursting strength of the guns was to construct the barrels from solid steel. Concerned about the possibility of air bubbles in Bessemer steel he applied extreme hydraulic pressure to the fluid metal during the casting process followed by similar hydraulic pressure, rather than the steam hammer, for forging. The method, which he called "fluid-compressed steel", was patented in 1865 and the metal produced was known as "Whitworth steel".

Between 1859 and 1862, he produced breech loading 3, 12, 32, 70, 120 and 130 pounder guns with excellent performance but the War Office were not impressed.

In formal shoot out trials against Armstrong's big guns in 1859, Whitworth's 3 pounder (1.4 kg) shot, at a range of 5.25 miles (8.5 km), deviated a mere three yards(2.7 m) from the centre of the target. At a range of 2 miles it hit the centre of the target in two out of five shots. His 12 pounders also achieved impressive accuracy at 5.8 miles.

Again in 1862, Whitworth's guns achieved superior performance to Armstrong's. With a target representing an ironclad warship, made up from a 4.5 inch (114 mm) steel plate backed up by 18 inches (457 mm) of teak and a further 0.625 inch (16 mm) steel plate, at a range of 600 yards (550 m), Whitworth's 131 pound (59.4 kg) projectile passed straight through all three layers and buried itself in the sand. Despite these successes, subsequent production contracts were awarded to Armstrong. As with the rifle, Whitworth was able to find overseas customers for his guns which included both sides in the American Civil War.

Whitworth's biographer, Norman Atkinson, implied that there were questionable procurement practices at the War Office. Whitworth and Armstrong were serious rivals in the gun making business. Both had superior products which had lost out in against inferior competition from government owned factories, the Woolwich Arsenal in the case of Armstrong's big guns and the Enfield Small Arms Factory in the case of Whitworth's rifles. Now the new big gun contracts had gone to Armstrong who had trained as a lawyer and had more friends in high places while Whitworth who had made is way up from the shop floor did not help himself with his aggressive and stubborn attitude and lost out.

By contrast such perverse government decision making, and the resulting wasteful use of resources, did not hamper their international rivals, the Krupp heavy arms industry, who had the constant and unstinting patronage of the German government, once they had established their credentials as an arms supplier, propelling them to the biggest company in Europe at the beginning of the twentieth century.

In 1897, ten years after Whitworth's death, Armstrong purchased Whitworth's company.

Between 1854 and 1878 Whitworth was awarded 20 patents relating to arms production. Guns using polygonal bores are still in production today.

Whitworth was a strong believer in the value of technical education. During his life he founded "Whitworth Scholarships" to advance mechanical engineering and in 1868 donated £128,000 (£10.1 million in today's money) to a similar government scheme. He also backed the Mechanics' Institute, now part of Manchester University.

At the time of his death in 1887, with the exception of Cecil Rhodes, Whitworth was the country's most generous benefactor. He bequeathed much of his fortune to the people of Manchester for public works and a hospital and appointed three legatees, providing them each with over £500,000 (£46 million today) to spend on projects of which they were expected to know he would have approved.

  • Footnote
  • The Crimean War (1853-1856) was The First Modern War and The First Media War.

    The Crimean War saw the first tactical use of modern technology changing the nature and immediacy of war. It included the following:

    • The use of armoured warships and submarine mines.
    • A 7 mile (11 km) long railway to carry supplies from the port of Balaclava to the troops besieging Sevastopol was constructed by the British army.
    • See also the Battle of Inkermam which highlighted the need for improved weapons technology to gain military superiority - still a never ending quest.
    • The electric telegraph, enabled better communications with front line troops but it also enabled the first "live" reporting of the state of battle from remote battlefields, not just to government headquarters, but also through newspapers to the general public.
    • It was also the first European war to be photographed.
    • The gathering, use and pubication of statistics by Florence Nightingale showed that casualties were seven times more likely to die of disease than from their wounds.

    These last three items, for the first time, brought home to the general public the chaos and true horrors of war creating great anxiety and much soul searching.

1851 German inventor Heinrich Daniel Ruhmkorff patents the Ruhmkorff Induction Coil capable of producing sparks 30 centimetres long. Basically a high turns ratio transformer, it was invented in 1836 by Irish priest Nicholas Callan.

1851 French physicist Léon Foucault proved for the first time that the Earth rotated on its axis by suspending a 28 kg brass-coated lead bob pendulum on a 67 meter long wire from the dome of the Panthéon in Paris. The plane of the pendulum's swing, though fixed, appeared to rotate by 360 degrees during the course of the day thus indicating the rotation of the Earth.

In 1852 Foucault performed similar experiments with gyroscopes. Though he was not able to sustain the rotation of the rotor for a full day, he was able to demonstrate that over a short period of time before friction slowed the rotor, the gyroscope maintained a fixed position in space independent of the Earth's rotation.

See more about Gyroscopes.

1851 American inventor and entrepreneur Isaac Merritt Singer invented the Singer Sewing Machine. Like many great inventors his inspiration drew on prior art to which he added his own contributions which brought the commercial success which had eluded his predecessors. In this case he improved the lockstitch mechanism of Elias Howe (See below), making it more reliable. He changed the needle movement from "side to side" to "up and down" enabling the use of a straight, rather than curved needle, and also enabling the machine to sew on a curved path. He also added automatic feed of the cloth and a presser "foot" to hold the cloth down against the upward stroke of the needle, and he introduced the foot treadle to power the movement of the needle and shuttle, replacing the hand-cranked mechanism used in all previous machines.

His major innovation however was in the marketing of the product. Previously sewing machines had been designed for industrial use and Singer launched the first domestic models in 1856 and pioneered the introduction of the Hire Purchase Agreement or Installment Payments, with $5 securing a machine, followed by monthly payments of $3 until the full purchase price was paid off. This allowed people of modest means to acquire relatively expensive capital goods. He later adopted the policy of accepting trade-ins against new purchases. These measures in turn increased the potential market for the machines and allowed the introduction of mass production methods for the first time, reducing the costs and increasing market potential still further. By 1870 the price of a new machine had been reduced to only $30.

Singer expanded into the European market, establishing a factory in Clydebank, near Glasgow, controlled by the parent company, becoming one of the first American-based multinational corporations, with agencies in Paris and Rio de Janeiro.

Singer's machine came towards the end of the Industrial Revolution which had largely benefited the textile industry with the mechanisation of spinning and weaving. His sewing machine dramatically reduced the time to make up garments while simultaneously improving both the quality and strength of the stitching giving further impetus to the textile industry by providing new markets for the increased textile production.

According to Brian Coats of the eponymous thread company, "To put sewing mechanisation into perspective, a skilled seamstress can manage 40 stitches per minute (spm) at full speed. The earliest machines claimed speeds of about 250 spm, Singer's machine in the 1850s could reach 900, and a contemporary domestic machine can do 1,500. Industrial machines will now get up to 10,000 spm and can sew coarse fabrics such as canvas and denim so fast that they will catch fire."

Just as important as the improvement in efficiency however, the sewing machine provided a means for families not just to make their own clothing, but also to start a small family businesses to supplement their incomes and improve their lives.

There had been many attempts at designing sewing machines in the past leading up to, and perhaps influencing, Isaac Singer's design in 1851 but most were unreliable or expensive and failed to gain commercial acceptance. These antecedents included the following:

  • 1755 German inventor Charles Weisenthal awarded an English patent for his invention of a sewing needle for use in a machine, but the description of the machine was not included in the patent, so it is unknown whether he actually designed a machine as well.
  • 1790 English inventor and cabinet maker, Thomas Saint was issued the first patent for a complete machine for sewing. It is not known if Saint actually built a working prototype of his invention. The patent describes an awl that punched a hole in leather and passed a needle through the hole. A later reproduction of Saint's invention based on his patent drawings did not work, though it did with work when some modifications were made.
  • 1810 German hosiery maker, Balthasar Krems developed an automatic machine for sewing caps but did not patent it. Like many others it never functioned well and was forgotten.
  • 1804 A French patent was granted to English inventors Thomas Stone and James Henderson for "a machine that emulated hand sewing."
  • The same year a British patent was granted to Scottish inventor John Duncan for an "embroidery machine with multiple needles."

    Both inventions failed and were soon forgotten by the public.

  • 1814 Austrian tailor, Josef Madersperger was issued a patent for a machine which made embroidery stitches, but it could not sew seams. By 1839 he had also received a patent for a machine suitable for chain stitching but this was not considered to be successful.
  • A chain stitch is formed by a single thread introduced from one side of the material only and is normally used for hemming or temporary stitching. It will unravel rapidly if the last stitch in the chain is not secured.

  • 1818 The first American sewing machine was invented by pastor John Adams Doge and John Knowles. Their machine failed to sew any useful amount of fabric before malfunctioning.
  • 1830 The first practical sewing machine was patented by the French tailor, Barthelemy Thimonnier. His machine had no transport mechanism, with the cloth being moved forward by hand, and used only one thread and a hooked needle that made an acceptable chain stitch like that used in embroidery. He set up a garment factory with 80 of his machines and had contracted with the French army to manufacture their uniforms but he was almost killed by an angry group of French tailors who feared being put out of work by his new invention and burned down his garment factory in 1841. Thimonnier died bankrupt in England.
  • 1833 American Walter Hunt invented the lockstitch sewing machine. In traditional lockstitch sewing, the needle thread interlaces with a separate under-thread, which is on a small bobbin over which the needle thread can pass to lock the stitch in place. This is a much more secure structure than the chain stitch.
  • Hunt's machine had two spools of thread and a curved needle with the eye at the point rather than in the shank as in conventional hand sewing needles. Hunt's needle passed the thread through the fabric in an arc motion; creating a loop on the other side of the fabric and a second thread carried by a shuttle running back and forth on a track passed through the loop creating a lockstitch. It was the first time an inventor moved away from attempting to duplicate hand sewing motions. Unfortunately his machine was only suitable for sewing straight seams.

    He later lost interest in the device because he believed his invention would cause unemployment and never patented it.

    Hunt also invented the safety pin.

  • 1844 The earliest known patent for a sewing machine which used two threads and the combination of an eye-pointed needle and a shuttle to form couched stitches was granted to Englishmen John Fisher and James Gibbons who received the patent for a lace making machine which was almost identical to the machines later made by Howe and Singer. The commercialisation of Fisher's machine was hampered by poor preparation of his patent application and subsequent legal challenges by Howe and Singer.
  • 1846 The first American patent was issued to Elias Howe of Spencer, Massachusetts for "a process that used thread from two different sources". It was basically a refinement of Hunt's idea. With a price tag of $300, equivalent of six months' wages, no single family could afford such a machine and Howe struggled to attract commercial interest in his invention in America. Trying his luck in England he eventually sold his first machine there but ended up in a debtors' prison in 1849.
  • Returning to Massachusetts he discovered that "his" lockstitch mechanism was being copied by many others and he embarked on a series of incessant law suits to protect his design. The most serious offender was Isaac Singer whose machine used the same lockstitch mechanism that Hunt had invented, but which Howe had patented, and in 1854 Howe sued Singer for patent infringement. The courts upheld Howe's patent, since Hunt had abandoned his design and not filed patent, giving Howe the exclusive patent rights to the eye pointed needle and Singer, as well as all others, had to pay royalties to Howe for the use of the patent on every machine manufactured.

    Howe then saw his annual income jump from $300 to more than $200,000 a year.

    In 1856 Howe, Singer and two other sewing machine manufacturers, "Grover & Baker", and "Wheeler & Wilson" agreed to pool their various patents creating the Sewing Machine Combination which extracted royalties of $15 per machine for the use of their patents by others.

    Between 1854 and 1867, Howe earned close to $2 million from his invention. During the Civil War(1861-1865), he donated a portion of his wealth to equip an infantry regiment for the Union Army and served in the regiment as a private.

    Elias Howe died in 1867, the year his patent expired.

  • 1849 American John Bachelder from Boston patented a sewing machine with a belt to feed the fabric along a horizontal sewing surface, though his invention was still only capable of making chain stitches. The patent for his feed mechanism was later sold to Singer.
  • 1851 American inventor, Allen B. Wilson, developed the rotary hook shuttle used extensively in lockstitch sewing machines which enabled much faster, vibration-free sewing speeds and the intermittent four-motion feed for advancing the material between stitches which is still used today.

Singer lived an unconventional lifestyle. He ran away from home at the age of eleven to join a travelling stage act and became a consummate showman who put his talents to good use in promoting his machines. He also lived a life of polygamy, marrying his first wife when she was only fifteen and subsequently fathering at least 24 children with seven common law wives and various mistresses.

On the darker side, when his business partner George Zeiber, fell seriously ill and was not expected to survive, Singer persuaded him to sign over his share of the company's assets which were at the time worth around $500,000 for only $6,000. Zeiber had helped Singer to start up the sewing machine company by giving him his entire life savings of $1,700 in return for a full share of the venture and even contributed his own ideas for improvement to the designs. Zeiber recovered however and though he managed to obtain menial employment from the company he never received any offer of compensation for his blatantly immoral treatment.

1852 English chemist Edward Frankland invented the notion of chemical bond and introduced the idea of valency, that an atom of one element could only compound with a definite number of atoms of another element.

1852 Joule and Kelvin (William Thomson) discovered that when a gas is allowed to expand without performing external work, the temperature of the gas falls. Now known as the Joule-Thomson Effect, it is the basis of nearly all modern refrigerators and gas liquefaction processes. (The Peltier Effect is also used in some special cooling applications)

For an explanation see Refrigeration Systems in the section on Heat Engines.

1852 American engineers William F. Channing and Moses Gerrish Farmer installed the first municipal electric fire alarm system using a series of electric bells and call boxes with automatic signaling to indicate the location of a fire in Boston, twenty four years before the advent of the telephone.

Farmer was a prolific inventor in the same mould as Edison. In the same year (1852) he also demonstrated diplex telegraphy, the simultaneous transmission of two signals in the same direction down a wire (or channel), the first example of time division multiplexing (TDM). It was based on two rotating switches, one at each end of the line which connected the transmission line alternately to each transmitter / receiver pair permitting sequential, interleaving of signals from each channel. Unfortunately he was not able to develop it into a practical system because of the difficulty of synchronising the receivers with the transmitters, a problem which was not solved until 1874 by Baudot.

In 1858 he did however patent a two battery duplex system similar to Gintl's 1853 design. (See next). As with the diplexer, there were obstacles to overcome before practical duplexers were ready for roll out. In this case it was the design by Stearns in 1872 which took the honours.

In 1853 Farmer also patented an improved battery.

1853 Austrian telecommunications engineer Julius Wilhelm Gintl working in Vienna, invented a method of duplex telegraphy, the simultaneous transmission of two signals in opposite directions down a wire (or channel). The first telecommunications duplexer - allowing simultaneous message transmission and reception. It was a two battery, "compensating" system with differential relays, in which two samples of the transmitted signal were arranged to cancel eachother in the local receiving relay but were able to operate the remote receiving relay normally.

In 1855 German engineer Carl Frischen working for Siemens & Halske registered of a patent for a simplified version of Gintl's design with only one compensating battery.

1853 The electric burglar alarm patented by American Minister Augustus Russell Pope. When a door or window was opened, it closed an electrical contact initiating an alarm. The rights to the patent were purchased by Edwin Holmes who began manufacturing and selling the alarms in 1858 and was subsequently credited with its invention.

1853 Almost 200 years after Newton, Scottish engineer William John Macquorn Rankine introduced the concept of potential energy for stored energy (In mechanical terms - energy based on position). Together with Kelvin they applied the concept to electrical potential whose unit of measurement they named the volt.

1853 Mathematical representation of the voltage-current relationships of capacitors (i = C dv/dt) and inductors (v = L di/dt) derived by Kelvin enabling the analysis of RLC circuits and the performance of telegraph cables. A more detailed model of the cable or transmission line, based on Kelvin's theory, but taking into account the distribution of the capacitance and inductance along the line, was developed by Kirchhoff in 1857.

1854 The fundamental idea of the electrical transmission of sound (the telephone) was published in the magazine "L'Illustration de Paris" by Belgian experimenter Charles Bourseul, working in France.

1854 Heinrich Geissler, a master glassblower in Bonn, Germany, was the first to make use of improved vacuum technology to create a series of astonishingly beautiful evacuated glass vessels into which he sealed metal electrodes. Geissler's vacuum tubes emitted brilliant and colourful fluorescent light when energised by a high voltage which aroused the interest of both scientists and artists of his day.

1854 English mathematician George Boole published "An Investigation of the Laws of Thought, on Which Are Founded the Mathematical Theories of Logic and Probabilities" in which he expressed logical statements in mathematical form. Now known as Boolean Logic it also used a binary approach to represent whether statements were "True" or "False". Starting with statements A, B or C etc. which are either true or false, (With binary or two valued logic they can't be anything in between. "Maybe" or "sometimes" are not acceptable.), other statements which are true or false, can be derived by combining the initial statements together using the fundamental logic operators AND, OR and NOT.

A simple example with two propositions A and B

A "Ford makes cars" is true.

B "Ford sells hamburgers" is false.

Using Boolean logic we can make the following more complex statements which are also correct.

A AND B is false.

A AND NOT B is true.

A OR B is true.

It seemed trivial at first and Boole's symbolic logic made little impact at the time until twelve years later it was picked up and developed by American logician Charles Sanders Pierce. However Boolean logic still remained in obscurity until it's value was eventually recognised by Claude Shannon in 1937 and used to make improvements to Vannevar Bush's analogue computer the differential analyser. Overnight Boolean algebra became a basic information processing concept now used in all modern digital computers.

See Boolean Logic and Digital Circuits.

Boole's wife, Mary Everest, niece of Sir George Everest after whom the mountain was named, was not blessed with the same logical mind as her husband. in 1864 at the age of 49 Boole caught a serious cold after walking two miles in the rain and giving a lecture still dressed in his wet clothes. His wife believed that a remedy should resemble the cause. She put him to bed and threw buckets of water over the bed since his illness had been caused by getting wet. Boole died of pneumonia.

1854 Irish inventor John Tyndall, in a demonstration at the Royal Institution, directed a beam of sunlight into the path of the curved stream of water pouring from a container. Due to total internal reflection at the boundaries of the water stream with the air, the light followed a zig zag path inside the arc of the water stream which acted as a light pipe. This is the phenomenon on which fibre-optics are based today.

Tyndall was a prolific inventor as well as a renowned populariser of science in the mould of Michael Faraday whom he counted among his friends.

Experimenting with cures for insomnia he died at the age of 73 from an overdose of chloral, a sedative administered by his wife.

1854 Scottish chemist John Stenhouse invented the gas mask. It was based on the ability of powdered charcoal to absorb large volumes of gases. Carbon based absorbers are still the most common filters in use today

1854 Italian priest and engineer Eugenio Barsanti in partnership with hydraulic engineer Felice Matteucci patented a four stroke, spark ignition internal combustion engine running on coal gas. They failed to sufficiently promote their business and when Barsanti died at the age of 43 in 1864 Matteucci was unable to carry on alone and Otto's recent (1862) similar design became the industry standard.

1855 British chemist and inventor Alexander Parkes produced the first synthetic (man made) plastic. By dissolving cellulose nitrate in alcohol and camphor containing ether, he produced a hard solid which could be molded when heated, which he called Parkesine (later known as celluloid). Unfortunately, Parkes could find no market for the material. In the 1860's, John Wesley Hyatt, an American chemist, rediscovered celluloid and marketed it successfully as a replacement for ivory. Thus was born the plastics industry which brought new opportunities to the electrical industry for both insulation and packaging.

1855 During the Crimean War (1853-1856), in response to military demands for large quantities of heavy guns and stronger metals to make them, English engineer and inventor, Henry Bessemer developed and patented a more effective, fast and inexpensive method of mass-producing steel from pig iron simply by reducing its carbon content. (See more about how the properties of iron and steel are determined by their carbon content). He devised a way of purifying the iron by blowing cold air through the molten metal to oxidise and separate out the impurities, which included silicon, manganese as well as the carbon, thus converting the high carbon pig iron into low carbon steel. The silicon and manganese oxides were removed as slag and the carbon monoxide burned off into CO2.

The chemistry governing the properties of steel was not well understood at the time and several industrial chemists and foundrymen had been working for some time on similar processes including James Nasmyth in England and William Kelly in the United States as well as others working independently. Kelly's explanation of the process was that the carbon content of the iron was burned out by blowing air through the molten iron. He claimed to have built a pilot plant but Bessemer was the first to build a full scale practical converter for which he submitted a British patent application in 1855 which was granted in 1856. On hearing of Bessemer's subsequent U.S. patent application in 1856 which was also granted, Kelly belatedly challenged this and applied for a U.S. patent himself for the basic chemical process which was granted in 1857. Kelly was however declared bankrupt the same year and was forced to sell his patent.

Bessemer's patent concerned the practical system in which the decarbonising process took place in a 20 feet (6 m) tall, egg shaped, tilting steel retort or furnace lined with refractory material and known as a Bessemer converter. Molten pig iron was fed into the retort from the top and air was blown in from the bottom. The process itself did not use any fuel. The oxidation reactions were exothermic and kept the temperature up and the iron molten. On completion of the conversion the retort was tilted to pour out the molten steel into moulds.

The initial process was successful in removing the impurities from the iron but it also removed too much of the carbon, the amount of which controlled the properties of the steel, and it left excess oxygen in the steel leaving it too soft to be useful.

The problem was solved the following year by metallurgist Robert Mushet who came to the rescue with a solution for managing the carbon content of the steel and in so doing ensured the economic viability of Bessemer's converter.

Further innovations allowing the use of cheaper and poorer quality iron ores were introduced by Gilchrist Thomas in 1876.

Bessemer's steel was much stronger than wrought iron and cast iron whose serious weaknesses had been exposed in some construction projects. It was also less expensive than wrought iron which it rapidly replaced.

Bessemer's converter, together with the innovations introduced by Muchet and Thomas, reduced the costs of steelmaking by about 80% but just as importantly it enabled the large scale production of steel. Previously steel had been made artisans in small quantities in crucibles and involved much highly skilled manual labour. Steel was expensive and its use was mainly limited to small, high cost products such as cutlery, scissors, hand tools, swords and small arms. Large metal structures were made of wrought or cast iron. The availability of mass produced, low cost, high quality, bulk steel in large pieces opened the door to a host of new applications for steel in railways, construction, ship building, heavy armaments, cable making and high pressure boilers and had a major impact on industrial development in the nineteenth century.

Bessemer was a prolific inventor with at least 129 patents to his name and made his first fortune selling "gold" paint, enabling passable imitations of the very expensive ormolu to be made. He made it from fine powdered brass suspended in a paint like solution. Rather than patenting it, he kept the process a closely guarded secret, carrying out parts of the production in four separate locations so that nobody could know the complete process. Bessemer's gold paint was used to adorn much of the gilded decoration which was popular at the time, and brought him great wealth.

See also Iron and Steel Making

1856 British metallurgist Robert Forester Mushet found an inexpensive way of providing more precise control of the carbon content of Bessemer steel. He recognised that Bessemer's steel was "over oxidised" and by adding small, controlled quantities of ferro-manganese, or spiegeleisen (German Spiegel - mirror and Eisen - iron) to the mix, this could be reversed. Spiegeleisen is an alloy of iron containing approximately 15% manganese and small quantities of carbon and silicon and when added to the furnace charge, the carbon in the spiegeleisen replaced a controlled amount of the carbon lost in the Bessemer conversion and the surplus manganese and silicon were oxidised by the oxygen supply and removed as slag. Mushet's innovation restored the strength to Bessemer's steel, making it suitable for rolling, forging and high temperature working.

The following year Mushet developed tungsten steel, the first commercial steel alloy. by adding about (8%) of tungsten to molten steel in a crucible. When forged at a low red heat, and allowed to cool gradually, the steel is naturally hard (so called self-hardening) and suitable for use as a tool steel. It maintains its edge and can cut much harder metals at much higher speeds than had previously been possible. Until then, the only way to produce hard tool steel had been to heat high carbon steel to a vey high temperature and to quench it quickly in cold water. Steel hardened in this way lost its hardness if it was overheated during use. Tungsten steel revolutionised the machine tools industry and industrial metalworking.

Muchet went on to develop and manufacture other iron and steel alloys with chromium and titanium.

Also in 1857 Mushet was the first to make durable rails for the railways from steel rather than the more brittle cast iron which had been used until then. Steel rails were also less costly to produce and were soon adopted worldwide.

Like many prolific inventors he was not a good businessman and never made any money from his inventions. He was however paid a small pension by Bessemer in recognition of his invaluable contibution to the converter process without which Bessemer's design would not have been viable.

1856 As an extension to his "dynamical theory of heat" published in 1851, Kelvin submitted a paper to the Royal Society outlining the "dynamical theory of electricity and magnetism" treating electricity as a fluid. It was these ideas which led Maxwell to develop his theory of electromagnetic radiation published in 1873.

In the same year Kelvin invented the strain gauge based on his discovery that the resistance of a wire increases with increasing strain.

1857 Following his discovery the previous year that the resistance of a conductor increases with increasing strain Kelvin also discovered that the resistance also changes when the conductor is subjected to an external magnetic field, a phenomenon known as magnetoresistance. In bulk ferromagnetic conductors, the main contributor to the magnetoresistance is the anisotropic magnetoresistance (AMR). It is now known that this is due to electron spin-orbit interaction which leads to a different electrical resistivity for a current direction parallel or perpendicular to the direction of magnetisation. When a magnetic field is applied, randomly oriented magnetic domains tend to align their magnetisation along the direction of the field, giving rise to a resistance change of the order of a few percent. The AMR effect has been used for making magnetic sensors and read-out heads for magnetic disks. See also GMR

1857 Wheatstone introduced the first application of punched paper tapes (Ticker tapes) as a medium for the preparation, storage, and transmission of data (another one of Bain's ideas) which was rapidly adopted in the USA to speed up the transmission of Morse code.

1858 The laying of the first Transatlantic Telegraph Cable from two wooden warships, Agamemnon and Niagara, was completed. - One of the greatest engineering feats of the nineteenth century. Financed by American entrepreneur Cyrus Field, it was designed and supervised by arrogant and incompetent amateur electrician, the aptly named, Dr Edward Orange Wildman Whitehouse, a former surgeon from Brighton. The cable was made up from seven copper strands carrying the signal, insulated with a treble layer of gutta percha held together by a jute yarn impregnated with tar, pitch, boiled oil and beeswax. The protective armouring consisted of eighteen strands of seven wires each of charcoal iron bright wire and the total weight of the cable was one ton per mile. The signal was carried in one direction by the cable while the return path was through the Earth.

Unfortunately the cable failed after less than a month in use, almost before the celebrations were complete, having transmitted only 732 messages. At its peak, over a period of 20 days, the cable was able to transmit in one direction 271 messages with an average of 10 words each, and 129 messages in the other direction, but the transmissions got steadily weaker with the message pulses becoming lost in the noise until it was taking half a day or more to send a message.

The signal pulses were generated from Daniell cells whose voltage was augmented using induction coils. In an attempt to solve the problem of weak signal levels, Whitehouse, advised by Morse it is claimed, increased the battery voltage from 600 Volts to 2000 Volts with disastrous results causing the breakdown of the cable's insulation. Kelvin, a consultant on the project, had advocated solving the weak signal problem by using more sensitive receiving equipment. He had the same year patented a mirror galvanometer (originally devised by Poggendorff in 1826) which enabled the detection of very weak signals for this purpose which arch rival Whitehouse was reluctant to use, preferring his own detectors. Kelvin's work on this high profile project and his design and management of the subsequent successful cable, laid by Brunel's Great Eastern and the Archimedes, in 1866 enhanced both his reputation and his bank balance as well as his already considerable ego.

One of the last messages sent over the original cable before it failed was from the British government to General Trollope, commander of the British forces in Halifax, Nova Scotia, rescinding an order to send two regiments of troops to help quell the Indian Mutiny, a rebellion against British rule. The original order had been sent by ship, the fastest way possible, a few weeks earlier, but by now the rebellion had been contained and there was no need for reinforcements. This single message of only nine words saved the British government £60,000 - more than paying back its investment in the cable.

The Archimedes, used to lay the second cable, was the world's first propeller driven steam ship and was named appropriately after the Archimedes Screw. Built in 1839 by Henry Wimshurst, father of the inventor of the Wimshurst electrostatic generator, it was sixteen years before the launch of the similarly equipped Niagara which had been used to lay the first cable.

It was not until 1956, almost a hundred years after the original cable was laid, that the Atlantic was spanned by the first telephone cable TAT 1.

1858 German physicist Julius Plücker at Bonn University, looking for a way to observe "pure electricity" separate from the conductor carrying it, discovered cathode rays. Aware of Hauksbee's glow discharge demonstrations in 1705, he commissioned local glassblower Heinrich Geissler to construct an evacuated tube with a metal plate or electrode at each end. Plücker and his assistant Johann Hittorf evacuated the tubes using Geissler's "mercury air pump", which produced a much greater vacuum than Hauksbee had been able to achieve. They created an electric discharge between the electrodes and observed what happened in the intervening empty space. At first, with partial vacuum, the tube was filled with an eerie glow just as Hauksbee had found but as the vacuum was increased the glow disappeared and a different greenish glow appeared on the glass near one of the electrodes. Hittorf showed that the glow was due to invisible rays which he called glow rays (now called cathode rays) which were emanating from the other electrode. He noticed that they cast shadows when objects were placed in their way indicating that they travelled in straight lines and that they were deflected by magnets indicating that they were electrically charged.

On further investigation Plücker filled the tube with different rarified gases to observe how they conducted electricity and discovered that each gas glowed with a bright characteristic colour like modern day fluorescent lights, years before their time. Although this amazing nineteenth century invention was picked up by local shopkeepers to entertain their customers it was never commercialised and seems to have been forgotten until it was rediscovered by Claude in the twentieth century.

1858 Scottish linguist and chemist Archibald Scott Couper and German chemist Friedrich August Kekulé von Stradonitz of Czech decent simultaneously and independently recognized that carbon atoms can link to each other to form chains giving birth to the study of organic chemistry. Prior to this thinking, it was believed that molecules could only have one central atom. Couper's publication was delayed for three weeks by his reviewer Charles Adolphe Wurtz and all credit for the discovery went to Kekulé. Couper was devastated and never published another paper.

1858 The electric burglar alarm, invented five years earlier by Augustus Russell Pope, was first commercialised by American inventor Edwin Holmes who is usually credited with its invention. Holmes' workshop was later used by Bell in the development of the telephone and he was the first person to have a home telephone. Holmes' Burglar Alarm business was eventually bought by the American Telephone and Telegraph Company in 1905.

1858 Italian chemist Stanislao Cannizzaro, using Avogadro's theories, resolved the confusion between atoms and molecules of the compounds of the same atoms allowing a unified scale for relative atomic mass of the elements to be developed.

1859 Scottish engineer and polymath William John Macquorn Rankine published his "Manual of the Steam Engine and Other Prime Movers" in which he provided a systematic treatment of the theory of steam engines. Building on Carnot's theory on the efficiency of heat engines which was based on the thermodynamic cycle of a single gaseous phase reversible process, he recognised that the relationship does not apply if a phase change is encountered, because the heat added or removed during a phase change does not change the temperature of the working fluid. He therefore developed a more general theory of heat cycles for vapour based, closed systems in which the working fluid was alternately vaporised and condensed. Now known as the Rankine Cycle, it describes the steam cycle used in modern day electricity generating plants.

See also Heat engines.

1859 French inventor Ferdinand Carré developed the first gas absorption refrigeration system using gaseous ammonia which he patented in 1860. The system does not depend on a compressor and instead uses heat to change the vapour back to a liquid. Due to the toxicity of ammonia they were mainly used for the commercial production of ice rather than for domestic applications. Since gas absorption systems with no moving parts can be built, they are still used today portable applications where no electricity supply is available.

For an explanation of how heat is used for cooling see Refrigeration Systems in the section on Heat Engines.

1859 English naturalist Charles Robert Darwin published On the Origin of Species explaining his Theory of Evolution that all species are descended from common ancestors by Natural Selection. There had been many similar speculations in the past but coming from a respected scientist and justified by evidence, though not yet possible by experiment, it created widespread interest as well as controversy since its findings directly contradicted the Creationist Theory as found in the bible and traditionally held by the church.

It was the culmination of many years' work by Darwin. As a self funded naturalist with the aim of collecting specimens, in 1831 he accompanied captain Robert FitzRoy's expedition to chart the coastline of South America sailing on HMS Beagle as a passenger. The expedition was planned to take two years but lasted almost five years during which Darwin was seasick most of the time while at sea. In South America he gathered fossils of extinct species and discovered later that they were allied to other species still living on the same continent. He noticed that finches present on three of the Galapagos Islands represented three separate species each unique to that particular island, and speculated that "one species does change into another" by the genealogical branching of a single evolutionary tree. It was not until over twenty years later after much further research that Darwin eventually published his theories.

1860 Spurred by the threat of the Civil War, entrepreneurs William H. Russell, William B. Waddell and Alexander Majors launched the Pony Express mail service to bring faster communications to the American West. It consisted of relays of men riding horses carrying saddlebags of mail across a 2000 mile trail between St. Joseph, Missouri, and Sacramento, California. The journey took between ten and twelve days with the pony riders covering around 250 miles in a 24-hour day. Soon the Pony Express had more than 100 stations, 80 riders, and between 400 and 500 horses, becoming part of the legend of the Old West. Sadly, despite its fame, the service lasted only 19 months when the completion of the Pacific Telegraph line in October 1861 rendered its service obsolete and its investors bankrupt.

1860 Belgian engineer Jean Joseph Étienne Lenoir patented the first practical internal combustion engine, a single-cylinder, two-stroke engine which burnt a mixture of coal gas and air. It was a double acting configuration with the power stroke and exhaust stroke taking place simultaneously on opposite sides of the piston. The fuel/air charge was not compressed before ignition which was provided by a spark from a Ruhmkorff coil. His patent also included the provision of a carburettor so that liquid fuel could be substituted for gas. The thermodynamic cycle on which the engine was based is named the Lenoir cycle after him.

Lenoir went on to build an experimental vehicle driven by his gas-engine, which managed to achieve a speed of 3 kms/hour in 1862.

1860 Munich clockmaker Christian Reithmann was granted a patent for a four stroke internal combustion engine, but lost out to Otto in subsequent legal patent disputes. He is also reputed to be the first person to use Hydrogen to power an internal combustion engine.

1860 The Lead Acid battery, the first practical rechargeable storage battery was demonstrated by Raymond Gaston Planté. It used spiral wound electrodes of Lead and Lead Oxide immersed in Sulphuric Acid and despite delivering remarkably high currents it remained a laboratory curiosity for two decades until the manufacturability and performance were improved by Fauré. The reversible battery cell chemistry had been observed 60 years earlier by Gautherot using copper electrodes but he failed to realise the potential of his discovery. (Sorry!) After over 145 years of development, patents are still being awarded for improvements to this simple device. Currently the value of Lead Acid batteries sold every year in the world is over $30 Billion and still growing.

1860 Concerned with the security of coal supplies, French mathematician Auguste Mouchout started work on the design of a solar powered motor, the first practical application of solar energy. The following year he was granted a patent for his design which used sunlight to boil water in a solar boiler to raise steam to drive a conventional motor. By 1865 his efficiency improvements included solar collectors or reflectors to catch and focus more of the sun's energy and also a tracking device to maintain the optimum orientation towards the sun.

1860 Maxwell showed that white light can be generated by mixing only three colours not the full spectrum as indicated by Newton.

The following year he published "On the theory of primary colours" in which he explained that any colour, not just white light, can be generated with a mixture of any three primary colours. He chose red, green and blue and produced the world's first colour photograph at a demonstration of colour photography to the Royal Institution in London in 1861. The subject was a tartan ribbon. Three separate monochrome images were made by exposing the ribbon through red green and blue filters respectively to make three lantern slides. A colour image of the ribbon was then created by projecting the three images from the slides simultaneously on to a screen through three separate lanterns, each equipped with the same filter used to make its image. See Maxwell's Colour Photograph.

Maxwell also developed the colour triangle, a practical tool for generating any desired colour. The vertices of the triangle represent the primary colours and the proportions of each primary colour required to generate the desired colour are determined by the distance of the desired colour from each vertex.

Maxwell's work could be considered to be the basis for modern colorimetry. Colour television and HTML, the language used to generate the colours in Internet browsers, work on the principle of combining different proportions of red, green and blue primary colours (RGB) to produce the full spectrum of colours as proposed by Maxwell.

1861 German schoolmaster Johann Philipp Reis made the first public presentation of a working telephone to Frankfurt's Physics Association (Der Physikalische Verein) and published "Telephony Using Galvanic Current". His transmitter and receiver used a cork, a knitting needle, a sausage skin, and a piece of platinum. Initially fifty units were made but their performance was erratic. Unfortunately Reis suffered from tuberculosis and did not have the time nor the energy to perfect his invention which he called the "Telephon", nor did he find the time to patent it. He died at the age of forty.

1861 Italian immigrant to the USA, fugitive from persecution as a supporter of the Italian unification movement, Antonio Santi Giuseppe Meucci, after constructing numerous devices which enabled the transmission of sound, demonstrated a working telephone system in New York. It was based on a system he had devised for communicating between his bedridden wife's room and his workshop in the basement. He called it the Telettrofono and it was reported in the local Italian language newspaper "L'Eco d'Italia" at the time.

Meucci was perpetually short of cash. He was a prolific inventor but was unsuccessful in commercialising his ideas and this consumed most of his income. Nevertheless he also provided financial support to the leader of the Italian unification movement Giuseppe Garibaldi during his exile in the United States.

Meucci continued to devise improvements to his telephone system, including inductive loading (in 1870) to enable longer distance calls. Unfortunately, in 1871 when he was incapacitated with serious burns from an explosion aboard the steamship Westfield on which he was travelling, his wife sold all his early models of telephone devices for $6. Meucci could not afford the $250 needed to patent his system, however in 1871 he did manage to obtain a cheaper official "Caveat" stating his paternity of the invention. After the sale of the old prototypes, in 1874 he handed some new models to Western Union Telegraph for evaluation and these were subsequently seen by Alexander G.Bell who had access to the laboratory where they were stored. In 1876 he was surprised to read in the newspapers that Bell was credited as the sole inventor of of this amazing new device. United States Patent No. 174,465, issued to Alexander Graham Bell in 1876, became recognized as the world's "most valuable patent." Meanwhile Meucci died in poverty in 1989 bringing to an end the US Government's fraud proceedings against Bell.

Meucci was finally recognised as the first inventor of the telephone by the United States Congress in its resolution 269 dated June 15, 2002, 113 years after his death.

1861 French engineer Alphonse Beau de Rochas patented the four stroke cycle the principle on which most modern internal combustion engines depend though he never built an engine.

1862 German travelling salesman and inventor Nicolaus August Otto demonstrated the World's first successful four-stroke, spark ignition, internal combustion engine. Prior to that, three patents for four stroke engines had been awarded, the first to Italian inventors Eugenio Barsanti and Felice Matteucci in London in 1854, the second to German engineer Christian Reithmann in 1860 and the third to French engineer Alphonse Eugène Beau de Rochas in 1861 however none of these engines achieved commercial application and there is no evidence that Otto was aware of these developments. In 1864 with Eugen Langen the owner of a sugar factory, Otto established N.A. Otto & Cie. (today's DEUTZ AG) to manufacture the engines. Initially they made only stationary engines but today the Otto cycle, named after him, is the operating principle used by the vast majority of the world's piston engines.

See also Heat engines.

1863 The British government passes the Alkali Works Act setting limits to the emissions of noxious substances, one of the first attempts to recognise and control environmental pollution. Alkali compounds were widely used at the time in the production of glass, soap, and textiles and were manufactured using the Le Blanc Process whose byproducts included various harmful emissions including hydrochloric acid, nitrous oxides, sulphur and chlorine gas. As a result, manufacturing plants were ringed by dead and dying vegetation and scorched earth and local residents suffered health problems. The new law was backed by the appointment of Alkali Inspectors who monitored pollution levels.

One of the founders of modern chemical engineering was George E. Davis who started his career as an "Alkali Inspector". He stressed the value of large scale experimentation (the precursor of the modern pilot plant), safety practices, and a unit operations approach for controlling chemical manufacturing processes.

1863 Ányos Jedlik, then physics professor at the University of Pest in Hungary, introduced his multiplying capacitor battery in which a bank of electrostatic generators was used to simultaneously charge a parallel bank (battery) of capacitors. The charged capacitors were then switched to a series connection so that the voltage appearing on the output terminals was equal to the sum of the voltages on the individual capacitors, enabling very high voltages to be built up. He was awarded a gold medal at the 1873 Vienna World Exhibition for his design.

1863 English geologist, Henry Clifton Sorby, developed techniques for studying the microscopical structure of iron and steel by polishing its surface and etching it with acid so that the structure could be observed with a with a microscope. In this way he discovered how the strength of the steel is determined by small but precise quantities of carbon in its content. After 4,000 years of empirical studies on steel making, Sorby's metallographic techniques at last provided a much needed tool for steel makers to understand, contol and improve the properties of their steel.

See also Iron and Steel Making

1864 Maxwell predicts that light, radiant heat, and "other radiations if any" are electromagnetic disturbances in the form of waves propagated through an electromagnetic field according to electromagnetic laws. It was not until 1873 that Maxwell provided the theoretical justification for his predictions.

1864 James Elkington the owner of a silver plating works in Birmingham, invented a commercial method for the refining of crude copper by the electrolytic deposition pure copper from a solution of copper salts. He patented the idea the following year and 1869 he founded the first electrolytic refining plant using this process, at Pembrey in South Wales.

1865 Clausius introduces the concept of entropy (from the Greek "transformation") defined as: "The internal energy of a system that cannot be converted to mechanical work" or "The property that describes the disorder of a system". He restated the Second Law of Thermodynamics, first outlined by Kelvin, in the context of system entropy as "In a closed system the entropy can only increase".

1865 French engineer Pierre-Émile Martin took out a license from German engineer, Karl Wilhelm Siemens and developed the open-hearth process in an attempt to circumvent the Bessemer patents. This process converts iron into steel in a broad, shallow, gas fired open-hearth furnace, by adding scrap iron including wrought iron or iron oxide as well as the alkaline limestone to molten pig iron until the carbon content is reduced by dilution and oxidation. The process allows for the production of larger batches of steel than the Bessemer process. It also allows precise control of the specifications of the steel but it is very slow.

See also Iron and Steel Making

1865 The International Telecommunications Union (ITU), the world's oldest international organization, an example of international cooperation at its best, was established to develop a framework agreement covering the interconnection of the first national and independent telegraph networks which at the time were built and operated to different and often incompatible standards. Its agreements cover interconnections, signalling and message protocols, equipment standards, operating instructions, tariffs, accounting and billing rules.

Today every telephone whether it is a new push button phone or an old dial phone, an analogue or digital cordless phone, a mobile phone, a payphone or a proprietary office system phone can be connected to every other telephone in the world. The same network is used to connect fax machines and the telephone message may be analogue or digital. The telephone message may be routed to an office in New York, a remote rural village in China or it can find the called party wherever they might be driving their car in Europe, passing through open overhead wires, underground cables, microwave links, fibre optic links, satellite links, undersea cables or local wireless links on the way. The signalling will be understood, the message will get through and the intermediate organisations carrying the call will get paid for their service.

With the advent of radio and later television, the ITU took on a similar role in managing the use of the radio spectrum, regulating frequency allocations, bandwidths and transmission powers to avoid the possible chaos of millions of transmitters from all over the world interfering with eachother. Despite the finite limitation on the available bandwidth, the ITU's regulatory framework also allows the flexibility to accommodate an ever growing number of users as well as new applications such as radar, cellular phones and GPS satellite navigation and the use of new modulation, multiplexing and transmission technologies as they have been developed to ensure the efficient use of this scarce resource.

The telephone network used to be the biggest machine in the world. Now with the advent of the Internet the machine is even bigger with computers as well as telephones connected together over the same network with modems carrying data and broadband terminals passing data, video and a host of new services down the same old wires and it still all works thanks to the ITU working anonymously in the background.

And all of this has been achieved with the ITU's recognition of "the sovereign right of each State to regulate its telecommunication"

See ISO and the Internet for how NOT to do it.

1866 Almost thirty years after Davenport had built the first practical electric motor using electromagnets in both the stator and rotor, the same technique was applied to the self energising dynamo. A wound rotating electromagnetic armature, replacing the weaker permanent magnet of the magneto, was invented almost simultaneously by Samuel Alfred Varley who's design was patented on 12 December 1866, by Werner Siemens who publicised his design on 17 January 1867, and by Charles Wheatstone who presented a paper to the Royal Society on 4th February 1867 about the principles involved. The design permitted much more powerful and efficient DC generators.

It was later revealed that a patent had been granted in 1854 to Mr. Soren Hjorth, a Danish railway engineer and inventor for a similar invention with self excited armature coils. Hjorth's patent is to be found in the British Patent Office Library.

The principle had also been demonstrated by Hungarian priest Ányos Jedlik in 1861.

The advent of practical dynamos provided a convenient, low cost, inexhaustible source of electric power overcoming many of the limitations of the battery and marked the beginning of electricity generation by electromechanical means rather than by electrochemistry. Rotary generators paved the way for the widespread use of electricity for both high power industrial applications and for consumer appliances in the home.

1867 The reversibility of the dynamo was enunciated by Werner Siemens but it was not demonstrated on a practical scale until 1873 by Gramme and Fontaine.

1867 Kelvin presented to the Royal Society, a paper "On a self-acting apparatus for multiplying and maintaining electric charges, with applications to illustrate the voltaic theory" describing a water powered electrostatic generator.

1867 Swedish chemist Alfred Bernhard Nobel was awarded a patent for the invention of Dynamite. Since 1859, Nobel had been investigating ways of safely manufacturing and handling nitroglycerine, the highly volatile explosive recently discovered (in 1847) by Ascanio Sobrero whom Nobel had known as a fellow student at the University of Paris. This was the first explosive that was more powerful than gunpowder but, though it could be highly effective, it was too unstable and impractical to use. In 1863, Nobel's first invention was the detonator followed in 1865 by the blasting cap, both of which ensured a more controlled explosion of the nitroglycerine and made possible the use of this much stronger explosive. In 1862 Nobel set up a factory to produce safer nitroglycerine, but development was fraught with difficulties. In 1864 an explosion at the manufacturing plant killed his younger brother and four others. Nobel persevered however and despite further accidents he discovered that by adding a powder of kieselguhr, a sedimentary rock consisting of fossilised remains of diatoms, the oily nitroglycerine could be transformed into a safer malleable paste which could be shaped into rods suitable for blasting rock by inserting the explosive into holes drilled into the rock. This was Dynamite.

In 1876 Nobel patented Gelignite, an even more powerful jelly-like explosive, formed from gun-cotton and other explosive materials, such as sodium or potassium nitrate, dissolved in nitroglycerine which was more stable and more easily formed into cavities either prepared or available for accepting the explosive charge. Without a detonator it simply burns rather than explodes and is thus reasonably safe to handle.

Nobel's explosives and detonators were soon used worldwide for mining and military applications with production supplied from 16 factories in 14 countries eventually including the Swedish Bofors armaments factory which he acquired in 1894. His development work continued and Nobel was awarded 355 patents for his inventions. All this brought him great wealth the bulk of which (31,225,000 Swedish Krona or £1,687,837) he bequeathed in his last will and testament dated 1895 (one year before his death) to establish the Nobel Prizes, to be awarded annually without distinction of nationality.

He wrote "The whole of my remaining realisable estate shall be dealt with in the following way: the capital invested in safe securities by my executors, shall constitute a fund, the interest on which shall be annually distributed in the form of prizes to those who, during the preceding year, shall have conferred the greatest benefit on mankind".

1867 The first practical typewriter was invented by Milwaukee newspaper editor Christopher Latham Sholes and his colleagues, Carlos Glidden and Samuel W. Soule. Sales did not immediately take off and early designs suffered from clashing and jamming of the keys when fast typing was attempted. At the suggestion of Sholes' financial backer, James Densmore, Scholes re-laid out the keyboard, into what eventually became the familiar QWERTY layout by spacing out pairs of keys which are often used together to avoid jams by effectively slowing down the typist.

Commercial success eventually came when the patents, manufacturing and sales rights were sold to the Remington Arms Company where the design continued to undergo many engineering improvements. One of the innovations was a minor keyboard layout change to replace the "period" key, previously allocated a place on the top row, with the "R" key so that their brand name "TYPE WRITER" could be typed out from the keys in only one row of the keyboard.

In return for the rights they obtained, Remington offered Scholes and Densmore either cash or royalties from future sales. Scholes took the cash, $12,000, a considerable sum in those days. Densmore took the royalties and eventually received $1.5 million.

1868 Invention of the Leclanché cell carbon-zinc wet cell by the French railway engineer Georges Leclanché. It used a cathode of manganese dioxide mixed with carbon contained in a porous pot and an anode of zinc in the form of a rod suspended in an outer glass container. The electrolyte was a solution of ammonium chloride that bathed the electrodes. The manganese dioxide acts as a depolariser absorbing hydrogen gas released at the cathode. The first practical battery product to be commercialised, it was immediately adopted by the telegraph service in Belgium and in the space of two years, twenty thousand of his cells were being used in the telegraph system. Later, it was also Alexander Graham Bell's battery of choice for his telephone demonstrations. Domestically however its use for many years was limited to door bells.

Leclanché's electrochemistry was implemented with a different cell construction by Gassner in 1886 to make more convenient dry cells which still survive today in the form of zinc-carbon dry cells, the lowest-cost flashlight batteries. Polaroid's PolaPulse disposable batteries used in instant film packs also used Leclanché chemistry although in a plastic sandwich.

1868 Maxwell analysed the stability of Watt's flyball centrifugal governor. Like Airy, he used differential equations of motion to find the characteristic equation of the system and studied the effect of the system parameters on stability and showed that the system is stable if the roots of the characteristic equation have negative real parts. He thus established the theoretical basis of modern feedback control systems or cybernetics.

1868 French engineer Jean Joseph Farcot patented improvements to machine control and in 1873 published a book entitled Le Servo-Moteur introducing the notion of servomechanisms which allow a small control system to control pieces of far heavier machinery.

1869 Prussian physicist Johann Wilhelm Hittorf published his laws governing the migration of ions. These were based on the concept of the transport number, the rate at which particular ions carried the electric current, which he had previously developed. He had noted in 1853 that some ions traveled more rapidly than others. By measuring the changes in the concentration of electrolyzed solutions, he computed from these the transport numbers (relative carrying capacities) of many ions.

1869 German chemist Julius Lother Meyer discovered the periodic relationship between the elements by plotting a graph of atomic weight against atomic volume, however its publication was delayed by the reviewer.

Working at the same time, this periodic relationship was also noticed by Russian chemist Dimitri Ivanovich Mendeleyev. By arranging cards with the names, atomic weights and some properties of the 65 known elements at that time, into rows and columns he noticed an underlying pattern. His Periodic Table of the Elements was published before Meyer's and the Periodic Table thus became attributed to Mendeleyev. Since then over 700 versions of the table have been produced.

Gaps in the table led scientists to speculate on the existence of hitherto unknown elements with predicted properties related to their positions in the table. The existence and properties of these elements was duly confirmed once suitable experiments could be devised.

1869 French paper manufacturer Aristide Bergès built several hydropower machines at Lancey near Grenoble. He directed water from a 200 metre high Alpine waterfall through a Girard impulse turbine, and later from a head of 500 metres through a Pelton turbine to power the machines in his paper mill. He was very active in promoting this energy source as a basis for industrial development in the Alpine valleys. Unfortunately "hydropower" has become confused with "hydroelectric power" and Bergès has been incorrectly credited with the invention, in 1869, of the first hydroelectric power installation, and even with coining the expression "hydroelectric power". In fact the first hydroelectric scheme was implemented in England by William Armstrong in 1878. Bergès did eventually introduce hyrdroelectric power at his plant in 1882 using a Gramme dynamo and these were only invented in 1873. Bergè dubbed this abundant energy source "Huille Blanc" which means "White Oil" in French, but this has almost universally been incorrectly translated as "White Coal" in English language technical publications.

1869 John Tyndall explained that the reason why the sky is blue is because of the scattering of light by dust and large molecules in the upper atmosphere, now known as the Tyndall Effect. He noticed that most light wavelengths pass through the atmosphere unaffected, but the wavelength of blue light is comparable with the spacing of the molecules in the atmosphere which therefore tends to be scatter the Sun's blue light. The effect is more commonly known as Rayleigh scattering, after Lord Rayleigh, who studied it in more detail some years later.

1870 New Yorker John Wesley Hyatt patented the first synthetic plastic, now called Celluloid, which was invented by Parkes in1855. He first used it as a coating for billiard balls and later for denture plates.

1870 John Player developed a process of mass producing strands of glass with a steam jet process to make what was called mineral wool for use as an effective insulating material. (Editor's Note - I have not yet been able to verify this first statement which could be an oft repeated internet myth related to the next paragraph. Please email me if you can help. The next statement is true.)

John Player had no connection with John Player cigarettes, a major brand in the 1980's. Nevertheless an unfounded rumour spread in the late 1980's and early 1990's, no doubt encouraged by their competitors, that the filters in John Player cigarettes contained fibreglass resulting in major damage to their market share.

1870's Austrian physicist Ludwig Eduard Boltzmann published a series of papers developing the theory of statistical mechanics with which he explained and predicted how the properties of atoms such as mass, charge, and structure determine the visible properties of matter such as viscosity, thermal conductivity, and diffusion. He showed that the kinetic energy of a molecule of an ideal gas is proportional to its absolute temperature. The ratio is equal to 1.38 X 10-23 Joules per degree Kelvin (J/K) and is called the Boltzmann Constant in his honour.

Boltzmann also derived a theoretical relationships for the thermodynamic entropy of a gas. 70 years later Shannon used an equivalent relationship to define the information entropy in a message.

Tragically ill and depressed, Boltzmann took his own life in 1906.

1871 Weber proposed the idea for atomic structure that atoms contain positive charges that are surrounded by rotating negative particles and that the application of an electric potential to a conductor causes the negative particles to migrate from one atom to another creating current flow.

1871 German scientist Steiner revived an apparently dead patient by passing a weak electrical current directly through his heart. The first recorded use of electric shock treatment for reviving people after cardiac arrest.

1871 After witnessing a death from smoke inhalation, John Tyndall invented the fireman's respirator or gas mask. See also Stenhouse

1872 PVC, Poly Vinyl Chloride first created by German chemist Eugen Baumann. It was not patented until 1913. In 1926 Waldo Semon invented a new way of making PVC into a useful product and he is now generally credited with discovering it.

1872 One of the many "Fathers of Radio" West Virginian dentist Mahlon Loomis was granted a patent for "a new and Improved Mode of Telegraphing and of Generating Light, Heat, and Motive Power". Although not a true radio system it was an attempt at making a wireless telegraphy system by replacing the batteries with electricity gathered from the atmosphere by means of flying kites attached to long copper wires. It used a Morse key between one kite wire and the ground to send signals and at the remote kite it used a galvanometer between the wire and the ground to detect the signals. It is claimed that signals using this method were transmitted over 14 miles, however it is questionable whether this system ever worked and it was never commercially exploited. Nevertheless the Guinness Book of Records credits Loomis with sending the first signals through the air. It was another sixteen years before Hertz demonstrated the existence of radio waves.

1872 American telecommunications engineer Joseph Barker Stearns of Boston developed the first practical telecommunications duplexing system. He accomplished this by using two different types of signals, one for each direction. In one direction he used varying strength signals (e.g. On or Off) which he detected with a common or neutral relay, while in the opposite direction he used varying polarity signals (Plus or Minus) which he detected with a polarised relay. The receivers were designed to respond only to signals of the appropriate type from the remote transmitter and to ignore local transmissions. Stearns' system effectively doubled the capacity of the installed telegraph lines and Western Union rapidly acquired rights to use it.

1872 British electrical engineer Josiah Latimer Clark invented the Clark Standard Cell which provided a reference voltage of 1.434 volts at 15 °C. The cathode was Mercury, in contact with a paste of Mercurous Sulphate, and the anode was Zinc amalgam in contact with a saturated solution of Zinc Sulphate.

1872 American mechanical engineer George Brayton patented his Ready Motor, a continuous combustion, two cylinder, two stroke, kerosene (paraffin) engine. It used a rocking arm coupled to a flywheel to drive the pistons alternately up and down. One piston was used to compress the air which was then mixed with a controlled amount of fuel and ignited by a continuous flame in a combustion chamber and fed into the second chamber where the hot gases expanded providing the power stroke. The modern gas turbine uses the same three fundamental components of Brayton's system, a compressor, continuous combustion burner and an expansion chamber from which work can be extracted and the thermodynamic cycle on which it based, heat addition at constant pressure, is now called the Brayton cycle. Brayton himself never made anything other than piston engines.

See also Gas turbines and Heat engines.

1873 Scottish physicist James Clerk Maxwell published his "Treatise on Electricity and Magnetism" in which, using a water analogy, he unified the laws of electricity and magnetism, distilling all electromagnetic theory into a set of four rules now accepted as one of the fundamental laws of nature. Now known as Maxwell's Equations, they were one of the most important scientific works of the century, not only explaining all electric, magnetic and radiation phenomena known at the time but also providing the theory describing light waves as well as the foundations for the two great theoretical advances of the twentieth century, relativity and quantum theory.

Maxwell's four equations express, respectively:

  • How electric charges produce electric fields - Gauss' Law for electric fields.
  • The absence of single magnetic poles. North and South magnetic poles always appear in pairs and the total magnetic charge is always zero. - Gauss' Law for magnetic fields.
  • How currents produce magnetic fields - Ampere's Law with an additional term called the displacement current showing that a changing electric field is equivalent to a current also inducing a magnetic field.
  • How changing magnetic fields produce electric fields - Faraday's Law of induction.

In mathematical vector form these complex relationships can be expressed very simply as:-


∇• D = ρ       or alternatively   ∇• E = ρ/ε0

∇• B = 0

∇x H = J + δD/δt

∇x E = - δB/δt

ρ is the free electric charge density (not including dipoles)
D is the electric displacement field or flux density = ε0E
B is the magnetic flux density = µ0H
H is the magnetic field
J is the current density
E is the electric field
∇• is the divergence operator
∇x is the curl operator
ε0  is the electric permittivity of a vacuum
µ0  is the magnetic permeability of a vacuum

Maxwell originally expressed his theory in 20 partial differential equations. They were subsequently simplified in 1884 by Oliver Heaviside who expressed them in vector form which is the form in which they are shown above.

As some physics teachers are fond of saying:

"The Lord said Let there be light and there were Maxwell's equations"

These four equations provided the theoretical justification of his 1864 predictions of the existence of radiation or electromagnetic (radio) waves, even though at that time there was still no evidence to demonstrate that such a phenomenon existed.

Maxwell showed that electromagnetic fields hold energy which is in every way equivalent to mechanical energy and that a changing magnetic field will induce a changing electric field which in turn induces a changing magnetic field, and so on, such that an electromagnetic wave is created in which the energy oscillates between the electric and magnetic fields.

He also showed that neither the electric wave nor the magnetic wave can exist alone. They travel together, always at right angles to, and in phase with eachother.

The velocity of propagation of the electromagnetic wave v can also be derived from Maxwell's equations as v = E/B the ratio between the electric field strength E and magnetic flux density B which is also equal to 1/√µ0ε0. From a knowledge of the magnitudes of µ0 and ε0 he determined that the velocity of propagation of the electromagnetic wave is constant and equal to the speed of light and that light is an electromagnetic wave.

Together with Lorentz law describing the forces on charged particles, Maxwell's equations form the basis of the theory of electrodynamics.

It is a measure of Maxwell's genius that with four elegant and concise equations he could not only account for the movement of a compass needle next to a current carrying wire but with the same equations he was also able to predict, understand and correctly characterise mathematically such a complex phenomenon as electromagnetic radiation that nobody had yet witnessed or even imagined.

Maxwell was initially encouraged and supported in his theories by Kelvin, upon whose earlier work he built, however in his lifetime Kelvin never accepted Maxwell's conclusions believing them too theoretical and not related to reality.

It was 1888 before his predictions were proved right by experiments carried out by Heinrich Hertz.

In the twentieth century, while Einstein's relativity theory required Newton's laws to be modified, Maxwell's equations remained absolute.

See more about Electromagnetic Radiation and Radio Waves today.

Maxwell also introduced statistical methods into the study of physics, now accepted as commonplace and made significant contributions to structural analysts, feedback control theory (cybernetics) and the theory of colour taking the first ever colour photograph.

Maxwell was a kind and modest man, universally liked. His ideas were ahead of his time but he made no attempt to promote his work. Despite his monumental achievement, it was Hertz' name rather than Maxwell's that has become associated with radio waves and radio propagation.

He died of stomach cancer in 1879 at the age of forty eight without seeing the experimental confirmation of his theories.

Like several Victorian scientists, Maxwell used poetry to describe his interests and his work. 43 of his poems on such riveting subjects as "A Problem In Dynamics", "British Association, Notes Of The President's Address", "To The Committee Of The Cayley Portrait Fund" and "Torto Volitans Sub Verbere Turbo Quem Pueri Magno In Gyro Vacua Atria Circum Intenti Ludo Exercent" about spinning tops, were published in 1882, after his death, by his friend Lewis Campbell.

Quotations about Maxwell:

When Michael Faraday was asked what was his greatest ever discovery he replied "James Maxwell"

"The Special Theory of Relativity owes its origins to Maxwell's Equations of the Electromagnetic Field" - Albert Einstein.

"Ten thousand years from now, there can be little doubt that the most significant event of the 19th century will be judged as Maxwell's discovery of the laws of electrodynamics" - Richard Feynman

1873 Belgian carpenter and instrument maker Zénobe Théophile Gramme in partnership with French engineer and inventor Hippolyte Fontaine developed the first reliable commutators for DC machines. (The commutator is the device which reverses the current in the rotor coil as it passes from the influence of one magnet pole to the next magnet pole of opposite polarity in order to maintain a unidirectional current in the external circuit).

They also demonstrated the reversibility of their dynamo by pumping water at the Vienna International Exhibition using two dynamos connected together, one, the generator, deriving motion from a hydraulic engine, provided electrical power to the receiving dynamo which worked the pump. It is said that they discovered the phenomenon by accident when an idle dynamo was mistakenly connected across another working/running dynamo and began motoring backwards. They did however realise that the importance of their discovery was not just the reversibility of the dynamo, but also the possibilities electrical power transmission. The fact that electrical power could be generated in one place and used in another.

1873 The first demonstration of electric traction in a road vehicle by Robert Davidson in Edinburgh using iron/zinc primary cells to drive a truck.

1873 English telegraph engineers, Joseph May and Willoughby Smith, while working with Selenium, noticed that its conductivity changed under the influence of light thus discovering the photoconductivity effect.

1873 Dutch physicist Johannes Diederik van der Waals deduced more accurate gas laws taking into account the volume of the actual molecules making up the gas and the intermolecular forces between them. The van der Waals forces, named after him, assumed that neutral molecules behaved like dipoles with a positive charge on one side and a negative charge on the other because their shape was distorted. The true nature of the forces between molecules was later explained in 1930 by Polish-born physicist Fritz London using quantum theory.

Van der Waals was awarded a Nobel Prize in 1910 for his work on the equation of state for gases and liquids.

1874 A thermo-electric battery based on the Seebeck effect powered by a gas heater introduced by M Clamond in France. Known as the Clamond pile or thermopile, it consisted of a stack of circular arrays of junctions of iron with a zinc-antimony alloy heated by a gas burner located in the centre of the stack. It generated 8 Volts providing a current of 2 to 3 Amps and supplied both heat and electricity to galvanising baths.

1874 Thomas Alva Edison invented the quadruplex telegraph, which was capable of sending four Morse coded messages simultaneously on a single channel. He amalgamated and rearranged the duplexer of Gintl, and Farmer and the diplexer of Stearns into a single system permitting two messages to be sent in each direction. As with Gintl's duplexer design, two relays in each terminal were unresponsive to outgoing signals, one of these relays responded to current increases of the incoming signals the while the other responded to current reversals of the received signals. Thus Stearns duplexing method of distinguishing between two signals was modified by Edison to separate the signals going in the same direction (diplexing) rather than in opposite directions (duplexing). This avoided the problem of synchronising the receivers with the transmitters. The quadruplex allowed the telegraph lines to carry four times the traffic and saved the telegraph companies millions of dollars.

Edison had started the development of his quadruplex system in 1873 in cooperation with Western Union using their facilities for his experimental work. He had agreed with William Orton, the president of Western Union, a development fee and that the patents for the design would be assigned to Western Union. When the design was complete Edison was given $5000 as part payment and $25,000 later. Orton also authorised a royalty payment to Edison of $233 per year before leaving on a business trip. While he was away, Edison was approached by George Jay Gould, railroad baron, Wall Street financier, stock manipulator and head of Atlantic and Pacific Telegraph Company, an arch rival of Western Union. He offered Edison $30,000 cash for the quadruplex patents and a job at Atlantic and Pacific. Edison accepted and wrote to Orton saying their arrangement had been a mistake and he revoked the assignment of patents to Western Union. Edison had sold the patents twice over. This earned him the title of "Master of Duplicity and Quadruplicity" bestowed on him by New York journalists. There followed years of litigation which only ended with the eventual amalgamation of the two telegraph companies. A portent of Edison's business methods to come. See Edison and Tesla.

Quadruplex telegraphs were eventually displaced by two new inventions, Baudot's multiplex telegraphy capable of eight or more simultaneous transmissions (see next) and Murray's teleprinter machines which did not use Morse code.(See following entry - Baudot code).

Edison set up his first small laboratory and manufacturing facility in Newark, New Jersey in 1871 to produce new designs for Western Union and others. In 1876 he moved to a larger facility at Menlo Park equipped to work on any invention opportunities he might turn up. This was the world's first industrial research and development facility and was where Edison's phonograph, light bulb and electrical power systems were developed. See more about Edison's Inventions.

1874 Jean Maurice Émile Baudot, an officer of the French Telegraph Service made major improvements in the telegraph system by bringing together the five unit code devised by Gauss and Weber, now called the five bit Baudot code, and the synchronous time division multiplex (TDM) system, proposed by Farmer in 1852, into a practical design for a printing telegraph.

The five bit code was the first truly digital code, each unit having only two logical states which he represented as + and -, later replaced by the more familiar 1 and 0 digital logical states we know today. This enabled 32 possible combinations or characters, the shortest practicable code for the number of characters to be transmitted. To enable a full alphanumeric code, Baudot used two special characters to switch between letters and numbers giving effectively 64 combinations, enough to allow for 26 characters for the alphabet and 10 numbers plus other miscellaneous punctuation and synchronisation codes. Input was by 5 keys. Later adaptations by Murray in 1903 (and others) used five hole punched tape to input the characters with a sixth row of smaller sprocket holes to feed the tape through the reader. The tape had the advantage that it could be punched off line and subsequently transmitted at high speed, but more importantly the tapes enabled the transmission speed to be controlled thus facilitating the multiplexing. Early teletypewriters also used Baudot code which eventually supplanted Morse code as the most commonly used telegraphic alphabet becoming known as the International Telegraph Code No.1.

Although the code is now named after Baudot, the five digit binary code was first proposed by Francis Bacon in 1605.

The Baudot distributor enabled four messages to be transmitted simultaneously. Multiplexing was achieved by using synchronised motors at either end of the line with brushes which connected each channel sequentially, for a fixed interval, to a single transmission line as the motor rotated. Synchronisation codes were sent down the line to keep the transmitter and receiver in step.

In modern circuits TDM is accomplished by interleaving the bit streams from the different channels.

The unit of measurement for data transmission rates of one character per second is named the Baud, a shortened form of Baudot, in his honour.

1874 German physicist Karl Ferdinand Braun discovered one way conduction in metal sulfide crystals. He later used the rectifying properties of the galena crystal, a semiconductor material composed of lead sulfide, to create the crystal detector used for detecting radio signals which Braun worked on with Marconi. Thus was born the first semiconductor device. Now called the diode, the cat's whisker detector was rediscovered and patented 30 years later by Pickard and Dunwoody.

1874 Irish physicist George Johnstone Stoney expanding on Faraday's laws of electrolysis and the notion that an electric charge was associated with the particles deposited on the electrodes during electrolysis, proposed that the minimum unit of charge was that which was found on the hydrogen ion and that it should be a fundamental unit. He named it the "electrine". In 1891, he changed the name to "electron". He calculated the magnitude of this charge from data obtained from the electrolysis of water and the kinetic theory of gases. The value obtained later became known as a coulomb. Stoney was unaware of the nature of the atom and "Stoney's electron" is a unit of charge, not to be confused with J.J. Thomson's sub atomic particle which Thomson called a corpuscle but which we now call the electron.

1874 David Salomons of Tunbridge Wells, England demonstrated a 1 H.P. three wheeled electric car powered by Bunsen cells.

1875 American physicist Henry Augustus Rowland was the first to show that moving electric charge is the same thing as an electric current.

He built up an electrostatic charge on a rotating gramophone (phonograph) record by rubbing it with woolen cloth. A magnetic compass bought in close to the spinning disk was deflected, the magnitude of the deflection increasing with the speed of the disk. This showed that a magnetic field is not only set up by a current moving through a wire but also by a moving electrostatic field.

1876 On March 10 in Boston, Massachusetts, Alexander Graham Bell, a Scottish emigré to the USA, invented the telephone. Bell filed his application just hours before his competitor, American inventor Elisha Gray, founder of Western Electric, filed notice with the same patent examiner, an outline of a telephone he planned to patent himself. What's more, neither man had actually built a working telephone. Bell in particular did not have a working microphone but he made his telephone operate three weeks later using the microphone described in Gray's Notice of Invention, and methods Bell did not propose in his own patent. Being a "system" using several technologies over which Bell claimed sole rights, it spawned more than 600 law suits mostly focused on whether the concept of modulating a DC current supplied by a battery was revolutionary or insubstantial and which of the many rivals had thought of it first. Legitimate claimants included Belgian experimenter Charles Bourseul (1854), German schoolmaster Johann Philipp Reis (1861) and impoverished Italian US immigrant Antonio Meucci (1861) to whom the idea is now officially credited by the American Congress (disregarding the prior work of Reis).

Bell's United States Patent No. 174465 became recognized as the world's most valuable patent.

Similar controversies surround the invention of radio, but that's another story.

In an attempt to find an assassin's bullet lodged in the body of US President James Garfield, in 1881 Bell hastily devised a crude metal detector based on the induction balance recently devised in 1879 by David Hughes. It worked but it didn't find the bullet, indicating that it was deeper than at first thought. It was later discovered that the detector had been confused by the newly invented metal bed springs under the mattress on which the President lay. (The President died after eighty painful days from complications arising from contamination of, and further damage to his wound by the dozen or more doctors probing his body in search of the bullet).

Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf, profoundly influencing Bell's life's work. It was his research on hearing, speech and sound transmission which eventually led him to the invention of the telephone.

In 1877 Bell married Mabel Gardiner Hubbard, a student from his school for the deaf, the daughter of Boston lawyer Gardiner Greene Hubbard. Hubbard senior, helped Bell set up the Bell Telephone Company with himself as president ably defending the company from the avalanche of lawsuits it faced.

In later life Bell moved to the relative seclusion of his estate in Nova Scotia where he declared himself to be sick of the telephone which he regarded as a nuisance, referring to it as a "beast". He crusaded tirelessly on behalf of the deaf and worked on a variety of projects including flight and aerofoils. At odds with his genuine concern for the deaf, he was an advocate of eugenics and carried out experiments with sheep. He was convinced that sheep with extra nipples would give birth to more lambs, and built a huge village of sheep pens, spending years counting sheep nipples, before the US State Department announced that extra nipples were not linked with extra lambs.

1876 Most iron ores, particularly those from Europe, contain substantial amounts of phosphorus which makes the steel produced from it very brittle. Up to that time it had been necessary to use costly phosphorus free ores from Wales and Sweden in the Bessemer converters used to produce the high quality steel. Welsh metallurgist Sidney Gilchrist Thomas discovered that by adding a chemically basic (alkaline) material to the Bessemer converter it can draw phosphorus impurities from the pig iron into the slag which is skimmed off, resulting in phosphorus-free steel. He later patented this process which was called the "Basic" Bessemer Process. Bessemer consequently replaced the original siliceous (acidic) refractory lining of his retorts with a limestone lining which produced lime (a base) when heated.

Thomas's innovation meant that iron ore from anywhere in the world could be used to make steel resulting in significant savings in production costs.

Thomas died of lung disease at the age of 34 in 1885.

See also Iron and Steel Making

1877 The telephone industry created the next major leap forward in the demand for batteries.

In Bell's original 1876 system the microphone was a passive transducer in which the acoustic power of the human voice provided the energy to create the varying electric currents which represent the sound and also to carry them down the wire to the receiver. In Bell's microphone, or transmitter in telephone parlance, sound waves impinge upon a steel diaphragm causing it to vibrate in sympathy. The diaphragm is arranged adjacent to the pole of a bar electromagnet and acts as an armature. The vibrations of the diaphragm cause very weak electrical impulses to be induced in the coil of the electromagnet. However these feeble signals were quickly attenuated as they passed down the telephone line until they were inaudible, severely limiting the range of the circuit and hence the potential of the telephone system.

During 1877 and 1878 German born American Emil Berliner, David Hughes, Thomas Edison, Bell employee Francis Blake and English curate Henry Hunnings, were each working independently on designs for improved microphones based on active transducers in which the acoustic power controls an external source of power. An active transducer provides an electrical signal with about a thousand times more electrical power than the acoustical power absorbed by the transducer and their designs considerably improved the range of the telephone at the expense of requiring power from a local battery. They all used variants of a carbon transducer which depend on the fact that the electrical resistance of some materials varies with the physical pressure exerted on it, various forms of carbon material, such as carbon granules, coke or lamp black being particularly sensitive. In the carbon microphones which they developed, during the call the battery current flows constantly in a closed circuit across a capsule of carbon material between two terminals one of which is a flexible diaphragm. The sound pressure variations are transferred to the carbon by the diaphragm thus causing the battery current to vary in response to the sound pressure. Edison's design used lamp black and had the added refinement of an induction coil or step up transformer which superimposed the sound information from the transducer on to a separate higher level DC current flowing through the secondary winding of the coil in the main transmission line so that an amplified signal appeared across the terminals of the secondary coil and the stronger DC current carried it further. A process we now call modulation.

Rather than patenting his ideas for the microphone, Hughes, who was already wealthy from his invention in 1855 of the printing telegraph, communicated his designs to the Royal Society in the February 1878 and generously gave the carbon microphone to the world. This earned him the wrath of Thomas Edison who laid claim to the invention, accusing Hughes of plagiarism and patent infringement. Two months later Berliner and Edison filed for patents on carbon microphones within two weeks of each other resulting in numerous bitter law suits which were eventually settled out of court. Hunnings patented the idea of using carbon granules which could carry higher currents but his patent was challenged by Edison's lawyers. Being a man of limited means he conceded and sold the rights for £1000 and went on Edison's payroll. Berliner went to work for Bell who bought his design for $50,000 and Edison's design, based on principles described by Hughes but using Hunnings' crushed carbon granules became the basis of the standard telephone transmitter and with a few refinements was used for over a hundred years.

Berliner went on to found Deutsche Grammophon Co. and his trademark image became a painting by English artist Mark Barraud of his dog "Nipper" listening to His Master's Voice for which Barraud was paid £50 for the painting and a further £50 for the full copyright. Berliner's other notable invention was the gramophone using a flat disk instead of the cylinder used by Edison.

1877 English experimenter Williams Grylls Adams and his student Richard Evans Day discovered that an electrical current could be created in Selenium solely by exposing it to light and produced the first Solar Cells naming the currents produced this way photoelectric. Although the effect was attributed to the properties of Selenium it was in fact due to the properties of the junction between the Selenium, now known to be a semiconducting material, and the Platinum metal used to create the connection for measuring the current.

Note: Confusingly the currents produced by solar cells, named photoelectric currents by Adams and Day, do not arise from the photoelectric effect in which light causes electrons to be emitted from the surface of the material by the process of photo-emission. Solar cells or photovoltaic cells are made of semiconductor material. The incoming light (photons) moves electrons from the valence band across the band gap to the conduction band and the resulting electron-hole pairs cause an internal electrical field to be set up across the P-N junction which separates them. In this way different charges on the two electrodes of the solar cell are created, and this potential difference can be used to drive a current through a wire.

It was not until 1954 that the efficiency of photovoltaic cells was improved enough to generate useful power.

1877, German, Ernst Siemens patented the first loudspeaker before the advent of electrical music reproduction.

1878 Electric alternator invented by Gramme and Fontaine.

1878 American physical chemist Josiah Willard Gibbs developed the theory of Chemical Thermodynamics introducing the free energy concept. When a chemical reaction occurs, the free energy of the system changes. The free energy is the amount of energy available to do external work, ignoring any changes on pressure or volume associated with the change of state. Thus the change in Gibbs free energy represents the total useful energy released by the chemical action which can be made available for doing work. When the free energy decreases, the entropy always increases, and the reaction is spontaneous. (The value of the free energy lies in the fact that its change is easier to measure than the change in entropy.)

He also developed fundamental equations and relationships to calculate multiphase equilibrium and the phase rule which specifies the minimum possible number of degrees of freedom, or variables such as temperature, pressure, concentration etc. in a (closed) system at equilibrium which must be specified , in terms of the number of separate phases and the number of chemical constituents in the system, in order to completely describe the state of the system. Gibbs' work laid the foundations for the theoretical representation of the energy transfers involved in chemical reactions. This allowed the performance (energy release) of galvanic cells to be quantified and predicted.

He published his work in the Transactions of the Connecticut Academy of Arts and Sciences, an obscure publication, published by his brother in law, with a very limited, mostly local, circulation. His work on thermodynamics, a major advance in the understanding of chemical reactions, therefore remained unknown until 1883, when Wilhelm Ostwald a Russian-German physical chemist discovered it and translated it to German.

In 1881 Gibbs published "Elements of Vector Analysis" which presents what is essentially the modern system of vector analysis. It permitted the presentation and analysis of complex relationships between multi-dimensional forces such as Maxwell's field theory to be simplified by the use of Gibbs' vector notation and methods. He also made important contributions to the electromagnetic theory of light. His later work on statistical mechanics was also important, providing a mathematical framework for quantum theory.

For all his major contributions to science, Gibbs was a modest man like Maxwell who shunned fame and fortune, living a quiet and contented, simple life as a bachelor, much admired by his students at Yale where he worked.

1878 French electrician, Alfred Niaudet, published "Traité élémentaire de la pile électrique" on electric batteries in which he described over a hundred different battery types and combinations of elements, indicating the growth and importance of battery technology.

Niaudet described the various chemical mixes and designs which had been used to address a range of design goals. The polarisation problem was solved by using non polarising chemical mixes which did not produce gases, or by using mixes which included depolarising agents or oxidants, which reduced any hydrogen emissions by combination with oxygen. Other recipes were used to achieve higher cell voltages, higher capacity, lower costs or longer life. Alternative constructions were designed to improve the convenience of use and current carrying capability or to reduce the cell's internal resistance. Later the possibility of electrical recharging became a design aim.

Examples not mentioned elsewhere on this web site are given below.

Non polarising 2 Volt primary cells were mostly based on potassium dichromate and often used two electrolyte gravity cells (See below). Examples were:

  • 1840 Grenet's single electrolyte potassium dichromate "Bottle" cell with adjustable carbon and zinc electrodes, favoured by Edison for his domestic lighting systems.
  • Voisin and Dronier's potassium dichromate "Bottle" cell, a variation on the Grenet cell with different electrode controls.
  • 1842 Poggendorff 2 electrolyte cell, similar to the Bunsen cell but with potassium dichromate replacing the nitric acid.
  • 1852 John Fuller's patented "gravity cell" which had a zinc cathode whose base was immersed in liquid mercury, in a porous container with a dilute sulphuric acid solution. The anode was carbon, surrounded by orange-red potassium dichromate solution and crystals, again in sulphuric acid. Similar cells were patented by Leffert. The following year Fuller improved on Daniell's original design to provide the Daniell cell chemistry as we know it today by replacing the aggressive sulphuric acid electrolyte with the more benign zinc sulphate prolonging the life of the cell. He also used the gravity cell construction and the design became very popular for telegraph applications.
  • 1854 Gravity cell proposed by C. F. Varley
  • Radiguet 2 electrolyte cell with electrodes of mercury and zinc and electrolytes of sulphuric acid and potassium dichromate.
  • Guiraud 2 electrolyte cell, a low cost cell with electrodes of carbon and zinc and electrolytes of brine and potassium dichromate

Potassium dichromate is strongly toxic and these cells consequently fell into disuse.

Gravity cells are two electrolyte cells which depend on a lighter electrolyte, such as zinc sulphate, floating on the top of a heavier electrolyte, such as copper sulphate, like oil and water. Normally, diffusion would soon mix the two liquids destroying the cell's efficacy, but if a current was drawn continuously the natural migration of the ions kept the electrolytes apart. This construction reduced the internal resistance of the battery by eliminating the porous pot from the current path. Gravity cells were used extensively in the telegraph and telephone industry, however the inconvenience of keeping the cells undisturbed to avoid mixing the electrolytes and also above freezing temperatures eventually led to their replacement.

Gravity cells which used zinc electrodes suspended in zinc sulphate or sulphuric acid were also called Crowfoot Cells because the shape of the zinc electrode resembled the bird's foot.

Other non polarising primary cells such as the Daniell cell were two electrolyte cells based on copper sulphate and sulphuric acid electrolytes. These included designs by the following inventors

  • Smée whose cell was the fore-runner of this class. It used zinc and copper electrodes and the copper electrode was coated with finely-divided platinum intended to cause the evolved hydrogen to form bubbles and detach themselves. An imperfect solution, but the cell was nevertheless popular in the electroplating industry.
  • Carré who replaced Daniell's porous pot with a parchment membrane.
  • Callaud, who in the 1860's, eliminated the porous cup in the Daniell cell perfecting the gravity cell construction.
  • Hill similar to the Callaud cell.
  • Meidinger whose design was popular in Germany. It used the Callaud chemistry but with a construction which was much easier to maintain.
  • Verité
  • Minotto who developed a gravity cell in 1862, based on Daniell's chemistry, for tropical use. It was used by the Indian PTT.
  • Essick whose cell was designed to operate at 70°C to achieve higher current outputs.
  • Tyer who patented a mercurial battery with silver and mercury-covered zinc in dilute sulphuric acid.

These cells all produced only 1 Volt which made them less attractive than the 2 Volt dichromate cells.

Many batteries at that time used elemental mercury for contacts or for preventing local action at the zinc electrodes. Impurities in zinc, such as iron or nickel, effectively created minute short-circuited cells around each grain of impurity which soon ate away the zinc. Pure zinc was far too expensive to be considered at that time, however in 1835 William Sturgeon discovered that the local action in the cheaper impure zinc could be eliminated if the zinc electrodes were amalgamated with liquid mercury.

In 1840 Sturgeon developed a long lasting battery consisting of a cast iron cylinder into which a rolled cylinder of amalgamated zinc was placed. Discs of millboard were used as separators and the electrolyte was dilute sulphuric acid.

Depolarising cells from the same period were usually based on nitric acid with a cell voltage of 1.9 Volts and included:

  • 1839 Grove cell, the first depolarising cell, it was a two electrolyte cell with nitric and sulphuric acid electrolytes and platinum and zinc electrodes
  • 1841 Bunsen cell, similar to Grove's cell, it replaced expensive platinum with cheaper carbon
  • 1853 Farmer cell, similar to Grove's cell with improved design of the porous pot.
  • 1854/5 Callan cell, the Maynooth battery, a two electrolyte cell. Expensive platinum or unreliable carbon cathodes were replaced by cast iron. The outer casing was cast iron, and the zinc anode was immersed in a porous pot in the centre.
  • Other variants on this theme were developed by Lansing B. Swan, Thomas C. Avery, Christian Schönbein, Archeneau, Hawkins, Niaudet, Tommasi and d'Arsonval.

Although these cells were popular, the acid decomposed rather than polarising the cell giving off toxic nitric dioxide gas which eventually led to their demise.

Other developments included:

  • The de la Rue silver chloride cell whose constant voltage and small size made it popular for medical and testing applications. The electrodes consisted of a small rod or pencil of zinc and a silver strip or wire coated with silver chloride and sheathed in parchment paper. The electrolyte was ammonium chloride contained in a closed glass phial or beaker to avoid evaporation.
  • The Schanschieff battery which used zinc and carbon electrodes and an electrolyte of mercury sulphate. It was suitable for portable applications such as reading and mining lamps.

All of the above cells were primary cells, but most were designed for re-use. In general, they used aqueous electrolytes enclosed in stout containers, often made of glass. Once the cell was discharged the spent chemicals could be replaced or replenished: - a form of mechanical recharging. High volume users such as the telegraph and telephone companies pioneered recycling, working with their battery suppliers to reprocess and recover expensive elements from the used electrolytes. (In 1886 Western Union recovered 3000 pounds of copper in this way.)

A further impetus was given to the search for alternative chemistries after 1860 when Gaston Planté demonstrated the feasibility of rechargeable cells with his Lead Acid battery.

All of the above primary cells were eventually superceded for PTT use by versions of Planté's rechargeable battery or by mains power.

For portable power, the Leclanché cell was one of the few surviving primary cells from this period.

1878 In a letter sent to the publication "Mechanic and World Science" Irish experimenter Denis D. Redmond described a 10 by 10 array of Selenium photocells each connected to a corresponding array of platinum wires which would glow when light impinged on the photocells. The system was the first to provide electric transmission of moving images, albeit silhouettes, only one year after the discovery of the photovoltaic effect and one year before Edison patented his light bulb. The system had no image scanning (later provided by Nipkow) so it required 100 channels to transmit the image. Nevertheless it was the forerunner of the modern television system.

The same year Portuguese professor Adriano de Paiva published "La téléscopie électrique basée sur l'emploi du sélénium" in a Portuguese publication "Commercio Portuguez", curiously written mostly in French with some Portuguese. It described a similar system to Redmond's which he called an electric telescope anticipating a different application from what eventually transpired.

It was another five years before practical photovoltaic cells were invented by Fritts.

1878 The bolometer, a very sensitive device for measuring very low levels of incident electromagnetic radiation, including infrared radiation, was invented by Samuel Pierpoint Langley. It works by measuring the heating effect of the radiation on the resistivity of a suitable conductive material. The name comes from the Greek bole ray of light, stroke, from ballein to throw.

Langley's bolometer used a Wheatstone Bridge with a sensitive galvanometer to measure the differential resistance between two Platinum strips coated with Carbon black, one exposed to the radiation and the other shielded from it. It was sensitive enough to detect the thermal radiation from a cow a quarter of a mile (400 m) away.

Modern bolometers use semiconductor or superconductor absorptive elements to pick up the radiation and are able to detect changes in temperature of less than 1/100,000 of a degree Celsius. They are commonly used to measure of the amount of solar energy reaching the Earth.

See also Langley's contribution to aviation.

See more about thermo-electricity.

1878 The invention which did more than any other to promote the use of electricity in the home, the incandescent electric light bulb, was patented in the UK by English physicist and chemist, Joseph Wilson Swan in 1878 and the following year in the USA by American, Thomas Alva Edison. (See following item).

Swan started his development of incandescent lamps in 1848 using platinum filaments but, because of the high cost of platinum and its short life before failing, he switched to carbon which could withstand the heat better. By 1860 he demonstrated a working device, and was granted a British patent covering a partial vacuum, carbon filament, incandescent lamp almost twenty years before Edison. Carbon unfortunately burns in the presence of oxygen and so must be enclosed in a vacuum and Swan's lamps still suffered from short lifetimes because of the difficulty of achieving a high enough vacuum. By 1878 however, vacuum technology had advanced sufficiently and Swan was able to produce and patent a reliable carbon filament lamp.

1878 The world's first electric power station was built by Sigmund Schuckert at the instigation of King Ludwig II went into operation in the Bavarian town of Ettal. It contained 24 dynamo electric generators based on a design by Siemens driven by a steam engine. It was used to power an array of Siemens carbon arc lamps to illuminate the Venus Grotto in the gardens of Ludwig's Linderhof Palace.

1878 Swedish engineer Karl Gustaf de Laval invented the centrifugal separator, the first practical bulk method for separating cream from milk. The milk container was spun up to over 1000 r.p.m. by a hand crank driving through a worm geared mechanism. He later applied the same principle of centrifugal force to the manufacture of glass bottles.

He is perhaps better known for his invention in 1882 of the impulse steam turbine, now named after him, which ran at a speed of 30,000 r.p.m.. The energy delivered to the impulse turbine rotor depends on the kinetic energy of the steam rather than its pressure so that de Laval's turbine could work over a wide range of steam pressures, however it needed to run at very high speed to achieve reasonable efficiency. A major component of the innovation was the development of the nozzle needed to deliver high kinetic energy steam to the turbine blades. It was a counter intuitive design with a convergent-divergent, hourglass, shape which could increase the velocity of the steam jet to supersonic speeds. The de Laval flared nozzle principle is now almost universally used in high speed gas jet applications including rocket engine exhausts.

Unfortunately at the time, there were few available materials needed to handle the mechanical forces associated with the high speed design and the turbine initially achieved limited success. Centrifugal forces on the rotor are immense, there were no suitable bearings for carrying the heavy, high speed rotor, and the rotation speed was too fast for most applications so that complex reduction gearing was required. All of these problems were eventually solved and turbines based on de Laval's designs are quite common today.

See diagrams and principles of de Laval's Turbine and Nozzle.

Gustaf de Laval was a prolific designer but a poor businessman and, despite his 92 patents and 37 companies, he died in extreme poverty.

See also Armstrong's hydro-electric scheme which also came on stream the same year.

1879 After an intensive search, starting in 1878, for suitable incandescent materials Thomas Alva Edison patented the Carbon filament, incandescent electric light bulb in the USA.

History is written by the winners and a certain mythology has built up around Edison's inventive genius. The light bulb itself is synonymous with bright ideas but also with Thomas Edison himself. Forgotten however is English experimenter Warren de la Rue's 1840 incandescent lamp using a platinum filament in a partially evacuated glass tube. Forgotten also are all the previous patents for electric lights similar to Edison's using carbon filaments in evacuated bulbs or bulbs filled with inert gas. These included American John W Starr from Cincinnati who was granted a UK patent in 1845 for a carbon filament incandescent lamp which he successfully demonstrated to Michael Faraday. Unfortunately Starr was found dead in bed the day after the demonstration at the age of 25, it is said, of "excitement and overwork of the brain" and nothing further became of his invention. Forgotten too are the similar inventions of Alexander Lodygin in Russia (1872), Henry Woodward and Matthew Evans in Canada (1874) and Joseph Swan in the England (See previous two items) who demonstrated an almost identical lamp to the Newcastle Literary and Philosophical Society eight months before Edison's "breakthrough". Edison actually sued Swan for patent infringement and the matter was finally settled out of court when the rivals formed the Edison and Swan United Electric Company.

Although Swan got there first, at the time, the only source of domestic electrical energy generally available was the battery and so all the lighting development took place using DC/battery power and it was Edison who popularised the invention in 1882 by providing the necessary electricity generating and distribution systems to power the lamps which made electric lighting practical. See Edison's generators.

Considering that Edison's name is almost synonymous with the invention of the light bulb it is perhaps surprising to note that in 1883 the US Patent Office ruled that a prior invention patented in 1878 by William Sawyer and Albon Man took precedence.

See also Tesla (1887)

Despite the unfortunate ending in 1874 of Edison's relationship with William Orton the head of Western Union, in 1877 Edison was hired once more by Orton to try to break Bell's patents on the telephone. Orton is quoted as saying that "Edison had a vacuum where his conscience ought to be". The battlefield was to be the telephone transmitter where Bell's design was inadequate but several others were already working on this. Edison provided an innovative design but it also used ideas developed by others and Edison's rights to these were only settled after litigation. He was paid over $100,000 for his solution by Western Union and this gave him the funding and the independence he needed to develop his creative talent. Bell's lawyers later successfully overturned Orton's main patent challenges to Bell's system although Edison's patents on the carbon microphone were upheld.

Edison, became known as the Wizard of Menlo Park, where he employed an army of engineers working on development projects and an aggressive team of lawyers. He made his first patent application in 1868 when he was 21 years old and over his lifetime he was granted 1,093 U.S. patents including 106 in 1882. In addition he also filed an estimated 500-600 unsuccessful or abandoned applications. This amounts to two successful patents per week during his most productive period and a patent application on average every eight working days over his long working lifetime of sixty years. Considering that three of these inventions, the light bulb, the phonograph and the movie projector for which he is famous each took several years of development, and at the same time he had a large company to run, you have ask your self how much Edison himself contributed to the patents which bear his name.

See also the Current wars.

Canadian author Peter McArthur is quoted as saying in 1901 "Every successful enterprise requires three men: a dreamer, a businessman and a son-of-a-bitch". The giants of the industry seem to embody all three of these characteristics at the same time.

The tale of the light bulb is a re-run of the disputes and dirty dealings around the invention of telegraphy by Morse and Edison, Bell's telephony,  Edison's carbon microphone and Bain's electric clock and Fax machine, stories and intrigues destined to be repeated with AC electrical power generation and distribution,  radio (Marconi),  radio and telephony (Pupin) and computers, and each new technology advance, though surprisingly the "invention" of the internet seems relatively free from such disputes and charlatans.

1879 Repeating the 1858 experiment of Plücker and Hittorf Sir William Crookes used a Geissler vacuum tube with an anode in the shape of a cross noticed that the cross cast a shadow on a zinc sulfide fluorescent coating on the end of the tube. He hypothesized that there must have been rays coming from the cathode which caused the zinc sulfide to fluoresce and the cross to create a shadow. He called these rays cathode rays. Crookes tubes were used by Röntgen in 1895 to demonstrate X-rays and by J. J. Thomson in 1897 in his discovery of the electron.

Crookes also invented the radiometer which detects the presence of radiation. It consists of an evacuated glass bulb in which lightweight metal vanes are mounted on a low friction spindle. Each vane is polished on one side, and blackened on the other. In sunlight, or exposed to a source of infrared radiation (even the heat of a hand nearby can be enough), the vanes turn with no apparent motive power.

Crookes was a believer in the occult and in the 1870's claimed to have verified the authenticity of psychic phenomena. He was knighted by Queen Victoria who, it is rumoured, had similar interests.

1879 American physicist Edwin Herbert Hall discovered that when a solid material carrying an electric current is placed in a magnetic field perpendicular to the current, a transverse electric field is created within the current carrier. Known as the Hall Effect in his honour. The voltage drop across the conductor at right angles to the current is called the Hall Voltage and is proportional to the external magnetic field. The phenomenon is now used in sensors for measuring magnetic field strength as well as current.

1879 Siemens Halske demonstrate an electric railway at an exhibition in Berlin. Power was provided from a separate generator which supplied the train via a third rail. A similar system was built in 1883 to run a commercial service along Brighton promenade in the UK by the son of a German clockmaker, Magnus Volk, an electrical engineer who had already completed the electric lighting of Brighton Pavilion. It was the world's first publicly operated electric railway when it opened and with some modifications his trains are still carrying passengers along the promenade today.

1879 Austrian physicist Josef Stefan formulated a law which states that the radiant energy of a blackbody is proportional to the fourth power of its temperature.

1879 After five years working as music professor, Welsh born American David Edward Hughes resigned in 1855 to patent a printing telegraph which became very successful in the USA and most of Europe, except Great Britain, bringing him international honours. In 1879 he invented the induction balance, the basis of the metal detector. It consists of two coils, one transmitting a low frequency signal and one connected to a receiver (detector) arranged in such a way that the receiver coil is close to, but shielded from, the transmitter coil so that in free space it does not pick up (detect) any signals from the transmitter. When the coils are brought near to a metal object, small perturbations in the magnetic field upset the balance between the coils causing a current to flow in the receiving coil thus indicating the presence of the metallic object.

The same year while working on his induction balance he noticed a clicking in a separate home made telephone ear-piece which was not connected in any way to the induction balance. He diagnosed this to be caused by a loose wire in his induction balance since the clicking stopped when the wire was firmly connected. He deduced that invisible waves, which he called aerial transmissions and which would today be called radio waves, were being emitted from a spark gap which occurred when the wire in the transmitting coil of the induction balance became disconnected and that the ear piece was picking them up. Investigating further he devised a clockwork device for opening and closing the spark gap and was able to pick up signals from the spark gap with his telephone receiver over ever greater distances, up to 500 yards, walking up and down Great Portland Street in London. Effectively he made the world's first mobile phone call. In 1880 Hughes demonstrated the phenomenon of radio communications to the Royal Society in London but the president, mathematician William Spottiswoode was not impressed. According to George Gabriel Stokes, Irish mathematician and physicist specialising in hydraulics and optics, who witnessed the demonstration, the phenomenon was explained by induction not radio waves. Discouraged, Hughes passed on to other interests and did not pursue his discovery. Eight years later Hertz was credited with the discovery of radio waves.

1880 The brothers Pierre and Jacques Curie predicted and demonstrated piezoelectricity. See more about the quartz crystal and piezoelectricity.

1880 Emile Alphonse Fauré in France patented pasted plates for manufacturing lead-acid batteries. The lead plates were coated with a paste of lead dioxide and sulphuric acid which greatly increased the capacity of the cells and reduced the formation time. This was a significant breakthrough which led directly to the industrial manufacture of lead-acid batteries.

1880 Herman Hammesfahr, a German immigrant to the USA, was awarded a patent for a durable and flame retardant fibreglass cloth with the diameter and texture of silk fibres. He showed a glass dress at the 1893 Chicago World Fair. (Also attributed to American glass manufacturer Edward Drummond Libbey founder of Owens-Illinois).

1881 Improvements to the Leclanché cell, to avoid leakage, by encapsulating both the negative electrode and porous pot into a sealed zinc cup were patented by J.A. Thiebaut.

1881 The first electric torch or flashlight patented by English inventors Ebenezer Burr and William Thomas Scott. The original lamps were designed as portable table lamps and powered by a wet cell battery in a waterproof box. At the time the first power station had not yet been commissioned and there were no households wired up for mains electricity. More convenient portable versions of the torch using the recently invented dry cells were introduced starting in 1883. They quickly became popular for bicycle and miners lamps.

1881 Lead acid rechargeable batteries were first used to power an electric car by M. G. Touvé in France.

1881 The first International Electric Congress or International Conference of Electricians convened in Paris to define the international terms for the electrical units of electromotive force (Volt), resistance (Ohm), current (Ampère) The Congress also specified the manner and conditions in which the units were to be measured. Up to this time there had been at least twelve different units of electromotive force, ten different units of current, and fifteen different units of resistance.

The standard Ohm was defined by the resistance of a specified column of mercury, the standard Ampère by the current which deposits metallic silver at a specified rate from a silver nitrate solution and the standard Volt was defined by the EMF produced by an electrical circuit passing through an electrical field at a specified rate. However since most laboratories were not equipped to generate a standard Volt in the specified manner, and in any case they used batteries to provide their source of electric potential, a new voltage standard was devised, based on the EMF produced by a standard Clark cell and this was adopted at the fourth International Electric Congress in Chicago in 1893. Unfortunately with the three standards each based on independent measured quantities, Volts did not always equal Amps multiplied by Ohms and the voltage standard had to be changed once more. The 1908 International Congress in London consequently changed the Volt to a derived unit based on the standard Ampère and standard Ohm.

1881 American engineer Frederick Winslow Taylor working at the Midvale Steel company introduced Time and Motion Studies or Work Study and Method Studies to streamline manufacturing and eliminate unnecessary work. They enabled major efficiency savings to be made and became the foundation of Scientific Management.

1881 Patent granted to William Wiley Smith for the induction telegraph used to communicate with moving trains. Soon afterwards improved versions were invented independently by Lucius J. Phelps (1884), Edison (1885) and black American Granville T, Woods (1887). The system consisted of a track-side wire or rail which could pick up signals from an induction coil mounted on the train, essentially acting as the primary and secondary windings of a transformer. The forerunner of the mobile phone.

Similar systems, based on the same principle, were also used for fixed wireless communications before the discovery of radio (Hertzian) waves.

1882 French physicist and physician Jacques Arsène d'Arsonval invented the moving coil galvanometer. It had shaped pole pieces which enabled it to have a linear scale and became the basis of all modern electromechanical analogue panel meters.

1882 Nikola Tesla, working in Budapest, identified the rotating magnetic field principle and the following year used it to design a two-phase induction motor.

1882 French chemists Felix de Lalande and Georges Chaperon introduce the first battery to use alkaline electrolyte, the Lalande-Chaperon cell, the predecessor of the Nickel-Cadmium cell. Using electrodes of Zinc and Copper Oxide with a Potassium Hydroxide electrolyte, it was rechargeable and produced a voltage of 0.85 Volts.

Up to that point, all batteries had used acidic electrolytes. They chose to investigate alkaline rather than acidic electrolytes because electrodes of most metals and their compounds are attacked by the acid. Lead is one of the few metals resisting the acids but it is very heavy and a weight savings would be secured by using almost any other metal.

1882 English amateur scientist James Wimshurst invented the Wimshurst Electrostatic Generator, the first machine capable of generating high voltage static electricity that was unaffected by atmospheric humidity. Static electrical charges of opposite polarity built up on its two fourteen and a half inch (38 cm) contra-rotating discs sufficient to draw a four and a half inch (12 cm) spark. Since the breakdown voltage for air is 30,000 Volts per centimetre, this small table top machine was capable of generating over 300,000 Volts. As a reliable source of high voltage electricity, it not only provided a practical power source for X-ray machines, but it was a boon to Victorian experimenters enabling them to carry out serious scientific investigations or to carry out dubious experiments in electrotherapy. Wimshurst's basic design is still used in electrical laboratories today.

James Wimshurst was the son of British ship builder Henry Wimshurst who built the Archimedes, the world's first propeller driven steamship, using the screw propeller patented in 1836 by John Ericsson. The Archimedes was used to lay the first successful Atlantic cable in 1866, replacing the ill fated 1858 original cable.

1882 Ayrton and Perry in England build an electric tricycle with a range of 10 to 25 miles powered by a lead acid battery and sporting electric lights for the first time. (Four years before the first Internal Combustion Engine car by Karl Benz)

1882 British engineer, James Atkinson patented modifications to the spark ignition, four stroke, internal combustion engine to circumvent Otto's patent. The design used a complex crankshaft arrangement to provide a longer exhaust (power) stroke than the induction stroke to improve the efficiency of heat cycle. The penalty was a more complicated mechanical mechanism as well as a larger, heavier engine. The industry however preferred the simpler Otto design and Atkinson's design did not achieve commercial success in his lifetime. Recently however the design is making a comeback as fuel efficiency becomes a priority.

See also Heat engines.

1882 In a display of optimism the first small domestic electrical appliances begin to appear, three months before power was available from the first electricity generating station. The electric fan, a two bladed desk fan was invented by Schuyler Skaats Wheeler manufactured by Crocker and Curtis electric motor company and the electric safety iron was invented by New Yorker Henry W. Seely.

1882 The world's first two large scale central electricity generating plants or power stations were completed by the Edison Electric Lighting Company. The first practical DC electrical power plants had already been installed in 1878, including a steam driven plant in Germany by Sigmund Schuckert and a hydroelectric scheme in the UK by Willam Armstrong. The first of Edison's generators to come on stream in April was at Holborn Viaduct in London providing DC Power for 2000 electric lamps. The second, in September, was at Pearl Street Station in New York City's financial district, supplying 82 customers with power for 400 lamps, increasing to 508 customers with 10,164 lamps two years later. Reciprocating, coal fired, Porter and Allen steam engines provided the motive power (about 900 horsepower) to 27 ton direct-current (DC) dynamos which produced 100 Kilowatts of power at 110 Volts. The overall energy efficiency is estimated at 6%.

Just 26 days after Edison's steam driven dynamos at Pearl Street were fired up, his hydroelectric dynamo at the Vulcan Street Plant on the Fox River at Appleton, Wisconsin came on stream supplying 12.5 kW of DC electric power to a home and two paper mills owned by a Mr R.H. Rogers. It was the first hydroelectric scheme in the world to supply commercial customers.

The project was instigated by Rogers, who was president of the Appleton Paper and Pulp Company and also of the Appleton Gas Light Company, after he heard about Edison's plans for Pearl Street. Being a ready-made user as well as having a ready-made customer, Rogers persuaded a group of investors to join him in funding the project.

Edison's DC generator was driven by a 42 inch (1 m) diameter Elmer pivot-gate, hydraulic turbine fed from a ten foot (3 m) head and running at a speed of 72 rpm. It was designed and patented by an inventor named Elmer from Berlin, Wisconsin and manufactured by a local company, Morgan and Bassett. Edison obviously had a much better public relations team than Elmer since this development is forever associated with Edison and Elmer's important contribution to this landmark project has been almost forgotten with information about him being almost impossible to find.

Despite these early breakthroughs, Edison's DC distribution scheme lost out to Tesla and Westinghouse's more efficient AC distribution scheme in the War of the Currents.

1882 Young American engineer William Joseph Hammer testing light bulbs for Edison noted a faint blue glow around the one side of the filament in an evacuated bulb and a blackening of the wire and the bulb at the other side, a phenomenon which was first called Hammer's Phantom Shadow. In an attempt to keep the inside of the electric lamps free of soot he placed a metal plate inside the evacuated bulb and connected a wire to it. He noted the unidirectional or "one-way" current flow from the incandescent filament across the vacuum to the metal plate but he was unable to explain it or realise its significance at the time. It was in fact due to the thermionic emission of electrons (not discovered until 1897 by J.J Thomson) from the hot electrode of the filament, flowing to the cold electrode of the plate creating in effect a vacuum diode or valve. In 1884 Edison was awarded a patent for a device using this effect to monitor variations in the output from electrical generators. The indicator proved ineffective however Hammer's discovery of thermionics was henceforth known as the Edison effect. The Edison effect is the basis of all the vacuum tube devices and thus the foundation of the electronics industry in the early 20th century. The first practical vacuum tube diode was patented by Fleming in 1904.

1882 English engineer John Hopkinson, an advocate of DC electricity generation and distribution systems, patented a three-wire, DC transmission system to supply two independent loads or a single load with double the voltage. (Not to be confused with Tesla, Dobrovolski, Wenström's later three phase AC distribution system which was carried on four wires). Hopkinson's system used one common wire between both circuits which enabled two, two-wire circuits to be supplied from a single generator with an output voltage of double the voltage of the individual circuits. He demonstrated the principle of load balancing to minimise the current flowing in the common, neutral line when two different DC motor loads are connected to the two parallel arms of his system. The system saved between 25 and 50 percent of the copper required for the conductors, depending on the balance between the loads. As in many other cases, Edison claimed the invention to be his.

In 1884 Hopkinson also published a paper analysing the synchronisation of parallel AC generators connected to similar systems. See more about Maintaining Grid Frequency Stability.

Hopkinson died tragically at the age of 49, together with three of his six children, in a mountaineering accident in Switzerland.

1883 Edison patents the fuse.

1883 Charles Edgar Fritts an American inventor built the first practical PhotoVoltaic module by coating selenium wafers with an ultra thin, almost transparent layer of gold. The energy conversion efficiency of these early devices was less than 1%. Denounced as a fraud in the USA for "generating power without consuming matter, thus violating the laws of physics" the idea of solar cells was taken up and commercialised by Siemens in Germany.

1883 Irish physicist George Francis FitzGerald suggests that Maxwell's theory of electromagnetic waves indicates that radio waves can be produced by an oscillating electric current.

1884 In an attempt to simplify Maxwell's Equations British engineer, physicist and mathematician Oliver Heaviside developed the branch of mathematics known as vector calculus. Maxwell expressed his theory with a cumbersome series of 20 partial differential equations with 20 variables representing the electric and magnetic fields. The equations for the fields were dependent on the coordinate system used. In each of cartesian, polar or spherical coordinate systems, three different equations were needed to represent the three possible components of the field directions. Heaviside defined the new vector operators, GRAD, DIV and CURL which enabled him to rewrite Maxwell's equations in vector notation, in a form which is independent of the coordinate system, with only four equations with four variables. Maxwell's equations are now, normally presented in the form developed by Heaviside.

Heaviside contributed much to communications theory but sadly remained unrecognised in his lifetime. In 1880 he patented the coaxial cable. In 1887 he investigated the causes of distortion in transmission lines showing mathematically that it was due to the distributed capacitance along the line, and more importantly, that it could be corrected or reduced by adding distributed inductance along the line. His suggestion to install induction coils at intervals along transmission lines was turned down by William Preece the assistant chief of the British Post Office who controlled the lines and it was published without fanfare in "The Electrician". The idea however was taken up in America by AT&T and by Michael Pupin a Columbia University lecturer in mathematical physics. Pupin subsequently patented the idea of inductive loading coils in 1899 and "Pupin coils" were implemented by AT&T throughout their network enabling them to increase dramatically the range of their telegraph and telephone cables. The patent made him extremely wealthy, much to Heaviside's chagrin, not so much for the money, which was never important to him, but for the recognition which he felt he deserved. While initially acknowledging Heaviside's contribution, Pupin changed his stance when the value of his patent became clear. His autobiography, "From Immigrant to Inventor", an example of the American dream, won him a Pulitzer Prize. In it, he rubs salt into Heaviside's wounds by mockingly crediting inspiration for "his invention" to a herdsman from his native Serbia who showed him how to send sound signals by tapping on the ground.

Heaviside is remembered today more for his 1902 prediction, published in the Encyclopaedia Brittanica, of the ionised layer in the upper atmosphere which reflected radio waves making long distance radio transmission possible by bending the radio wave around the curvature of the Earth. Known as the Heavisde Layer, or the Kennelly-Heaviside Layer since Arthur Edwin Kennelly an expatriate Briton working in the USA also independently made the same prediction at the same time, its existence was verified in 1924 by Edward Victor Appleton.

Heaviside's life was not a happy one. He was not a wealthy man and worked much of his life with no regular income. His mathematics were difficult to understand even by the most technically literate and the injustice of Pupin's exploitation of his ideas affected him greatly. An embittered man, he never married, living an eccentric existence in bare rooms furnished with granite blocks. In later life his appearance became more and more unkempt and children would taunt him in the street, shouting "Poop. Poop. Pupin".

1884 British engineer, Charles Algernon Parsons, graduated apprentice of William Armstrong, produced his first steam turbine in 1884. Coupled to a dynamo of his own design it generated 7.5 kW of electricity, but failed to generate any commercial interest in it. One of his key innovations was the compound reaction turbine which used a set of stator blades to redirect the steam after it had passed through the first rotor blades so that it could be directed through a second rotor and hence to further rotor/stator pairs. This allowed much higher power outputs and efficiencies to be achieved. See photographs of Parsons turbine showing the blades.

To publicise his invention, in 1894 he took out a patent on the turbine and commissioned a 100 foot long steel boat, the Turbinia, to demonstrate its capability. Initially he did not achieve the desired speed through the water as its propellers, rotating at 18,000 rpm, suffered from the previously unheard of problem of cavitation and churned up the water as bubbles formed behind the blades due to sudden pressure reduction. However by slowing down the turbine and modifying the propellers he was able to achieve a speed of 34.5 knots from a 2,300 hp turbine. Still his target customer, the Admiralty, was unimpressed. According to Parson's biographer Ken Smith, Parsons dictum was "If you believe in a principle, never damage it with a poor impression. You must go all the way". His opportunity came at the 1897 Spithead Naval Review of 160 of the navy's ships, arranged to show off the might of the Royal Navy to Queen Victoria and invited foreign dignitaries on the sixtieth anniversary of the queen's accession to the throne. The navy's best boats were capable of no more than 30 knots and the Turbinia astonished the gathered crowd by steaming up and down the navy's lines leaving their fastest boats in her wake. The steam turbine's future was assured. Today 86% of the world's electricity is generated using steam turbines.

See more about Steam Turbines and how they work.

See more about Steam Engines


1884 Charles Renard uses a Zinc/Chlorine Flow Battery to power his air ship La France with the chlorine being supplied by an on board chemical reactor containing Chromium Trioxide and Hydrochloric Acid.

1884 Swedish chemist Svante August Arrhenius working at the University of Uppsala published his PhD thesis on the Galvanic Conductivity of Electrolytes explaining the process by which some compounds conduct electricity when in solution. He proposed that when a compound like table salt NaCl (sodium chloride) was dissolved in water, it dissociated into positively and negatively charged "ions" (Greek for "the ones that move" or "wanderers") Na+ and Cl- whose motions constituted a current. These ions drift freely through the solution but when positive and negative electrodes are introduced into the electrolyte, as in electrolysis, the ions drift towards the electrode of opposite polarity. He defined acids as any substance, which when dissolved in water, tends to increase the amount of H+ hydrogen ions and bases as any substance, which when dissolved in water, tends to increase the amount of OH- hydroxide ions. (These definitions do not cover all possibilities which are now known to exist).

His 1884 thesis was treated with disbelief and was given the lowest passing grade at the time, however he was vindicated with the discovery of the electron by J J Thomson in 1897 and his disparaged thesis won him the Nobel Prize for chemistry in 1903.

In 1887 Arrhenius was the first to develop the theory quantifying the rate at which chemical reactions proceed, now known as Arrhenius Law.

In 1896 Arrhenius was also the first to describe the "Greenhouse Effect" and its causes.

1884 French chemist Henri Louis Le Chatelier discovered the chemical equivalent of Lenz Law of electromagnetism. It was published in simpler form 4 years later as: "If the conditions of a system, initially at equilibrium, are changed, the equilibrium will shift in such a direction as to tend to restore the original conditions". The conditions refer to concentration, temperature and pressure. Le Chatelier's Principle allows you to predict which way the equilibrium will move when you change the reaction conditions, and helps provide ways to increase the yield in a chemical reaction.

1884 German engineering student Paul Gottlieb Nipkow patents an electromechanical image scanning system the basis for television raster scanning. The system was made possible by use of the photoconductive properties of the element selenium recently discovered by Fritts. Previous attempts at transmitting images such as Redmond's had used one channel, or pair of wires, to transmit each picture element. Nipkow's design needed only one pair of wires for transmitting the image. He used a rotating disk with holes, through which the scene could be observed, arranged circumferentially around the disc in a spiral between the centre and the edge. Light passing through the holes as the disk rotated, impinged on a selenium photocell, generating an electrical signal proportional to the brightness of the scene which could be transmitted down wires to a receiver. As the disk rotated it produced a rectangular scanning pattern or raster which scanned the scene. The number of scanned lines was equal to the number of holes and each rotation of the disk produced a television frame. A similar Nipkow disc, synchronised with the transmitter disc, was used in the receiver and the received electrical signal was used to to vary the brightness of a light source illuminating a projection screen. The light passing through the rotating disk formed a raster on the projection screen allowing an image to be built up. Like all television systems, it depended on the principle of "persistence of vision" and rapid scanning was needed to ensure that it worked. This was the first example of transmitting moving images electrically down a wire however it is not clear whether Nipkow actually built a working system. The signals from the selenium were very low and needed amplification for a practical system and it was not until 1907 that De Forest's audion made this possible.

1885 German physicist Eugen Goldstein using a cathode ray tube with a perforated cathode discovered rays of positively charged particles emerging from holes on the sides of the cathode and moving in the opposite direction of cathode rays. He called these rays Canal rays. The particles were later determined by Wien to be protons with a mass almost 2000 times the mass of an electron.

1885 Italian physicist Galileo Ferraris discovered the rotating magnetic field that he applied to the first 4 pole induction motor. He did not patent his invention but offered it freely to "the service of mankind". In 1888 he published a paper describing an electrical alternator and around the same time a similar device was patented by Tesla.

1885 Russian Nikolai Benardos and Polish Stanislav Olszewski were granted a patent for an electric arc welder with a carbon electrode. They are considered the inventors of modern welding apparatus although electric arc welding was first proposed by Lindsay fifty years earlier in 1835.

1885 Engineers from the Ganz factory in Hungary, Ottó Titusz Bláthy, Miksa Déri and Károly Zipernowsky demonstrated at the National Exhibition in Budapest, a high voltage alternating current distribution system using toroidal transformers which they also designed. The entire exhibition was illuminated by 1,067 X 100 Volt incandescent lamps supplied by 75 transformers taking their power from a 1,350 Volt 70 Hz distribution system.

In modern day power transformers the windings are usually wound around a laminated iron (Silicon steel) core (either directly or on a former). The Ganz transformers at the time provided a breakthrough in efficiency because of their unique construction which improved the transformer's magnetic circuit. The primary and secondary windings were first wound together in the shape of an annular ring and this formed the core of a torus. The magnetic circuit was made by toroidally winding thousands of turns of iron wire around the copper windings, completely encasing them in magnetic material which almost filled the inner space of the ring.

Bláthy also patented the first alternating-current kilowatt-hour meter in 1889.

1885 German mechanical engineer, Karl Friedrich Benz designed and built the world's first practical automobile to be powered by an internal combustion engine. It was a "three wheeler", powered by a water cooled 958cc, 0.75hp four stroke engine based on Nicolaus Otto's patent with electric ignition and differential gears. He was granted a patent for the gasoline fuelled "motor carriage" the following year and built his first four wheeled car in 1891. His invention marked the start of the slow demise of the battery driven car.

1886 After Bláthy's demonstrations of alternating current power distribution the previous year, New Yorker, William Stanley Jr in the USA patented the "Induction Coil", invented by Michael Faraday in 1831, what we would now call a transformer. This opened the door to the widespread use of AC power for domestic applications. Battery power, once the only source of electricity in the home, now had a serious competitor.

1886 Carl Gassner of Mainz patented the carbon-zinc dry cell which made batteries the convenient power source they are today. It used the basic Leclanché (1868) cell chemistry with zinc as its primary ingredient with the chemicals being encased in a sealed zinc container which acted as the negative electrode. A carbon rod immersed in a manganese dioxide/carbon black mixture served as the positive electrode. Initially the electrolyte was ammonium chloride soaked into the separator which was made of paper, but by adding zinc chloride to the electrolyte the wasteful corrosion of zinc when the cell was idle was reduced - adding considerably to the shelf life. A bitumen seal prevented leakage. Although the technology has been refined by over a century of development, the concepts and chemistry are the same as Gassner's first cells.

Previously most wet primary cells could be recharged mechanically by replacing the spent chemicals. The used electrolyte could then be recycled to recover the basic constituents. The advent of the dry cell marked the beginning of the single use, throwaway, primary cell since it was no longer easy or possible for the user to replace or replenish the active chemicals.

1886 Patent granted to American chemist Charles Martin Hall for the electrolytic process for extracting aluminium from its bauxite ore, aluminium oxide or alumina. His discovery was made in a laboratory he set up at home, using home made Bunsen batteries, shortly after finishing his undergraduate studies. The process was discovered simultaneously by French chemist Paul Héroult and is now called the Hall-Héroult process.

Aluminium is the most abundant metal and the third most abundant element in the Earth's crust but, because it is highly chemically reactive, it does not occur in nature as a free metal. Before Hall discovered a practical way of extracting it from its ore, aluminium metal was extremely rare and cost more than gold.

On an industrial scale the process uses enormous amounts of electricity, consequently aluminium extraction plants are normally located close to the sources of cheap hydroelectric power.

Hall went on to found ALCOA, the Aluminium Company of America.

See also Héroult

1886 English inventor Herbert Akroyd Stuart built the first compression ignition engine which he patented in 1890. In subsequent patent disputes with Rudolf Diesel who patented a similar engine in 1893, Akroyd Smith's claim to priority was upheld.

1887 Kelvin patented the electrostatic voltmeter.

1887 The Michelson-Morley experiment to determine the properties of the luminiferous aether (also called the "ether") and their influence on the speed of light was carried out in Cleveland, Ohio by Albert A. Michelson professor of physics at the Case School of Applied Science, and Edward W. Morley professor of chemistry at Western Reserve University.

At the time, the results of their experiment did not confirm the prevailing theory or conventional wisdom and the experiment was judged to be a failure. It was later realised however that it was the theory which was faulty, not the experiment, and that they had discovered a most important physical phenomenon.

For 200 years after Boyle had shown that sound can not be transmitted through a vacuum, scientists had theorised that light must similarly require a medium to support the transmission of its wave motions. They called this medium the luminiferous aether (from the Greek "light bearing substance") and since light can be received from distant stars, they speculated that this aether must fill the Universe. Since light can travel through a vacuum, it was assumed that even a vacuum must also be filled with this mysterious aether and since material bodies can pass through it without obvious friction or drag it must have an unusual combination of properties. The Michelson-Morely experiment was set up to investigate these properties.

Since it was assumed that the aether permeated the entire Universe, it must therefore be fixed and the movement through this stationary aether of the Earth as it orbits around the Sun at a speed of over 67,500 mph (108,000 km/h) would be experienced by observers on the Earth as an aether wind. This wind would either increase or decrease the speed of light depending on the direction of the Earth with respect to the direction of the wind.

It was reasoned that, the speed of light would be constant with respect to the proposed stationary aether, but if the Earth was moving with respect to the aether then that motion could be detected by comparing the speed of light in the direction of the Earth's motion and the speed of light at right angles to the Earth's motion.

Assuming the speed of light with respect to the stationary aether is c, light travelling perpendicular to the direction of the aether wind will also be c. However with an aether wind speed of v, we would expect the speed of light travelling in the same direction as the aether wind, but upstream against the wind, to be diminished from c to c-v while the speed of light travelling downstream with the wind would be augmented from c to c+v.

Using the above assumptions, the expected average speed c' of the light beam travelling back and forth in the same direction as the aether wind will be slower at c' >= c (1- v2/c2). This is because the time gained from travelling downwind is less than the time lost travelling upwind. Since v is very much smaller than c, the speed difference between the two perpendicular paths will also be very small and difficult to measure.

Michelson had the solution to this problem. In 1881 he had constructed an interferometer, a sensitive optical device that compares the optical path lengths for light moving in two mutually perpendicular directions. See diagram of Michelson's Interferometer and an explanation of its functions.

The Michelson-Morley experiment used an adapted version of Michelson's interferometer and expected to find interference fringes due to the different light speeds, and the consequent different transit times over equal distances, of light beams travelling in the same direction of the aether wind compared with light beams travelling perpendicular to the aether wind. They mounted their apparatus on top of a large block of sandstone about a foot (30 cms) thick and five feet (1.5 M) square, and floated it in a circular trough of mercury to minimise vibrations and to allow the set up to be rotated so that measurements could be taken with respect to any angle of the Earth's direction through space. One arm or light path was aligned with the direction of travel as the Earth, the other perpendicular to it.

To their chagrin, no difference in the light speeds between the paths was found and they initially believed that they had failed. Despite repeating the measurements many times over as well as making modifications and improvements to their equipment, still no difference in light speeds between the two directions was found.

Attempts to explain this puzzling result were made in 1889 by Irish physicist George Fitzgerald and by Dutch physicist Hendrik Lorentz in 1892. They hypothesised that the aether did exist and that the pressure of the assumed aether wind on the arm of the interferometer in line with the wind would cause the arm to contract and this shorter distance could compensate exactly for the supposed slower speed of light against the wind along this arm. This would in turn explain the lack of destructive interference between the light travelling along the interferomter's two perpendicular paths. According to their calculations the length L of the arm in the direction of the aether wind would contract by an amount equal to equal to L/γ where γ (gamma) = 1/√(1-v2/c2) and v is the difference between the speed of light in the two perpendicular interferometer arms. Simultaneously, the time for light t to traverse both ways along the interferometer arm in the direction of the aether wind would increase to . The correction factor gamma γ was later named the Lorentz transformation in honour of Lorentz.

Unfortunately their hypothesis was proved to be incorrect and the subsequent measurements have all confirmed the absence of a luminiferous aether.

The momentous conclusion was that the luminiferous aether did not exist and that the speed of light in a vacuum is the same for all observers, regardless of the motion of the light source. By inference from Maxwell's recently (1873) formulated laws, the same conclusions also apply to electromagnetic radiation.

The Michelson-Morley experiment ultimately led to the proposal by Albert Einstein in 1905 that the speed of light is a universal constant.

Michelson was awarded the Nobel Prize in 1907, becoming the first American to win the Nobel Prize in Physics.

1887 Arrhenius publishes the equation named after him showing the exponential relationship between the rate at which a chemical action proceeds and its temperature, the rate doubling with each 10°C rise in temperature.

1887 American inventor Elihu Thomson patents the electric welding (resistance welding) process. The technique used for making battery interconnections.

1887 By 1887 huge strides had been made in the electrical power industry since the invention of the first practical dynamo 20 years earlier.

1887 - 1890 Croatian-born physicist Nikola Tesla filed for numerous US patents on AC distribution systems and polyphase induction motors and generators based on the polyphase rotating field principle he discovered in 1882. This enabled inexpensive and unlimited electric power to be brought to the home consumer thus sealing the fate of the DC system and the use of DC in domestic applications.

Contracted for $50,000 by Thomas Edison (a promoter of DC transmission) to improve his DC dynamos Tesla worked night and day to deliver the solutions on time a year later to Edison but Edison refused to pay saying he had been a joking about the contract. Tesla resigned in disgust and went to work for George Westinghouse promoter of AC distribution and Edison's arch rival. Edison with some success, spent the rest of his life trying to undermine Tesla.

For two years after Tesla left, Edison staged a morbid public relations campaign in what became known as the notorious current wars to demonstrate that the Westinghouse AC distribution system was dangerous by promoting the AC powered electric chair for carrying out the death penalty and calling such executions "Westinghousing". At the same time he arranged public executions of farm animals which he attended personally in the courtyard of his laboratory using AC power, starting with dogs and escalating to calves then horses. (The original electric chair using high voltage and direct current (DC) as a means of humane execution had been invented in 1881 by New York steam-boat engineer, dentist Alfred P. Southwick.)

Edison's system itself was responsible for a number of deaths due to mechanical failure or ignorance as the deceptively similar high voltage wires were installed overhead near to the more familiar low voltage telegraph wires.

In 1915 Reuters and the New york Times carried reports that Tesla and Edison were to share the Nobel Prize for physics. Mystery surrounds what happened next, but no such prize was awarded and it is claimed that Edison, whose fame and wealth were secure, turned down the award to deprive Tesla of a much needed $20,000. Others claim Tesla himself turned it down not wanting to be associated with Edison whom he called "a mere inventor". The Nobel Foundation did not deny that Tesla and Edison had been their first choices.

Despite having over 800 patents Tesla died penniless.

1887 British engineer, born in Liverpool, with the distinctly un-British name of Sebastian Pietro Innocenzo Adhemar Ziani de Ferranti, (his father was a photographer and his grandfather, Guitarist to the King of Belgians), designed the generation and distribution systems for Deptford Power Station (1887-1890), which at that time was the largest in the world. Power was supplied by four single phase 1000 kW, 10,000 Volts, 85 cycle/sec alternators. Ferranti pioneered the use of Alternating Current for the distribution of electrical power in Europe authoring 176 patents on the alternator, high-tension cables, insulation, circuit breakers, transformers and turbines.

Ferranti also designed the first flexible high voltage cables for power distribution using wax-impregnated paper for insulation, a technique which was used exclusively until synthetic materials became available.

In the same year Ferranti also patented the induction furnace in which materials are heated by eddy currents induced within the material itself, generated by placing the material in the magnetic field of an induction coil.

1887 British physiologist Augustus Waller of St. Mary's Medical School in London published the first human electrocardiogram - recorded by lab technician Thomas Goswell.

1887 Fibreglass invented again by Charles Vernon Boys a physics demonstrator at the London's Royal College of Science who produced glass fibre strands by using the end of an arrow fired from a miniature crossbow to draw strands of molten glass from a heated vessel.

1887 German physicist Heinrich Rudolf Hertz discovered the photoelectric effect, that physical materials emit charged particles (electrons) when they absorb radiant energy. During electromagnetic wave experiments he noticed that a spark would jump more readily between two electrically charged spheres when there surfaces were illuminated by the light from the other spark. Light shining on their surfaces seemed to facilitate the escape of electrons.

The photoelectric effect was not explained until 1905 by Albert Einstein who used quantum theory proposed in 1900 by Max Planck.

1888 Heinrich Hertz is generally considered to be the first to transmit and receive radio waves. (But see also Hughes 1880). Hertz demonstrated the existence of electromagnetic waves, predicted by Maxwell in 1864 and justified theoretically by him in 1873, by transmitting an electrical disturbance between two unconnected spark gaps situated 1.5 metres apart. He set up a wire loop containing spark gap (the transmitter) through which a large spark was deliberately generated. This caused a small spark to jump across another spark gap (the detector) at the ends of a similar wire loop situated near to but not connected to the transmitting loop. The wire loops were effectively the world's first radio transmitting and receiving antennas.

He showed that radio waves travel in straight lines and can be reflected by a metal sheet.

Hertz died of a brain tumour at the age of 36 without ever seeing the practical applications which resulted from his discoveries. The unit of frequency is named the Hertz in his honour.

Like Hughes who discovered the phenomenon before him, Hertz failed to see the potential of radio for communications. Hertz told one of his pupils " I don't see any useful purpose for this mysterious, invisible electromagnetic energy".

Hertz' (or should we say "Maxwell's") radio waves now form the basis of all broadcast radio and television, radar, satellite navigation, mobile phones and much of the backbone of the world's communications systems. Maxwell provided the theoretical basis for the technology, Hertz showed it was possible but there were many, many worthy contributors whose inventions were needed to make it happen. Each country had its national champions who invented transmitters, receivers, antennas, tuners, detectors, filters, oscillators, amplifiers, transducers, displays, batteries and other components and a variety of coding, modulation, multiplexing, compression, encryption schemes, communications protocols and software. There were however five players associated with the fundamental developments in radio technology whose contrasting fortunes are worth mentioning briefly here namely: Marconi, Fessenden, Armstrong, Watson-Watt and Dippy.

See more about Electromagnetic Radiation and Radio Waves today.

1888 German physicist Wilhelm Ludwig Franz Hallwachs discovers another example of photoelectric emission. (Becquerel's was the first). Following up Hertz' experiments on how light affected the intensity of spark discharges, he noticed that the charge on an insulated, negatively charged plate leaked away slowly but when it was illuminated with ultraviolet light the charge leaked away very quickly. On the other hand a positively charged plate was unaffected by the light. This phenomenon, now known as the Hallwachs effect, was later explained to be due to the emission of electrons from certain metallic substances when exposed to light. It is the basis of the modern photocell. Note that this is different from the photovoltaic effect in solar cells.

1888 Spanish naval officer Isaac Peral built the first electrically powered submarine.

Later the same year the French launched Gymnôte, a 60 foot submarine designed by Gustave Zede. It was driven by a 55 horse power electric motor, originally powered by 564 Lalande Chaperon alkaline cells by Coumelin, Desmazures et Baillache with a total capacity of 400 Amphours weighing 11 tons and delivering a maximum current of 166 Amps. These batteries were replaced in 1891 by 204 Laurent-Cely Lead acid cells, which were in turn replaced in 1897. Although the batteries were rechargeable, they could not be charged at sea.

An electric submarine was also built by Polish inventor Stefan Drzewiecki for the Russian Tzar in 1884.

1888 Austrian botanist Friedrich Reinitzer investigating the behaviour of cholesterol in plants observed cholesteryl benzoate changing into its liquid crystal state, nine years before the invention of the CRT. For nearly a hundred years afterwards liquid crystals remained little more than a chemical curiosity until they were eventually adopted for use in LCD displays. See Dreyer (1950) and Fergason (1969)

1888 An irate Kansas City undertaker Almon B. Strowger patented the automatic telephone exchange.

When Alexander Bell first started selling telephones, he sold them in pairs because the few subscribers that there were at the time could connect to eachother directly. As the number of telephones grew, the need quickly arose to be able to connect to more than one subscriber, but running telephone lines from each subscriber to every other subscriber was impractical so the telephone exchange with a manual switchboard was born. Each subscriber was connected to a switchboard at the exchange. When a subscriber wanted to make a call he would call the exchange and the telephone operator would connect his line to the called party line via a cable on the switchboard to complete the circuit. Strowger was infuriated by this system, since there was another undertaker in town who happened to be friends with the telephone operator and whenever someone called the operator asking to be put through to an undertaker, all the calls went to his competitor. He therefore set about designing an automatic exchange that would eliminate the need for operators.

In Strowger's design the telephone dial sent a series of pulses corresponding to each digit of the telephone number. At the telephone exchange the dial pulses would step a 10 position, rotary selector switch, called a uniselector, to a telephone line corresponding to the digit. For multi-digit telephone numbers, each line of the uniselector corresponding to the first digit was connected to a second uniselector, so that 100 lines could be accessed with 11 uniselectors. By adding a third stage, with 100 more uniselectors, 1000 subscribers could be accessed. In practice the uniselectors were designed as two-motion selectors with two dialling stages in one bank making 100 possible connections. The first stage was a rotary movement and the second stage was a linear movement with the selector stage moving up and down to connect to a set of contacts arranged vertically. This system formed the backbone of telephone communications in many countries of the world for almost 100 years.

Interestingly, before the familiar rotary telephone dial was invented, Strowger's first telephone sets used push button dialling, which required the caller to provide the pulses by tapping on the keys.

1888 AT&T engineer, Hammond V. Hayes developed the common battery system which permitted a central battery to supply all telephones on an exchange with power, rather than relying upon each subscriber's own troublesome power supply. It allowed all telephone signalling and speech to be powered from single large central 24 Volt lead acid batteries mounted in central telephone exchanges, eliminating the need for magnetos and Leclanché cells to be installed in every subscriber's premises. The system is still in use today.

1889 Elihu Thomson invents the motor driven recording wattmeter.

1889 Russian engineer Michail Osipovich Dolivo-Dobrovolski working for AEG in Germany made the first squirrel cage induction motor. In 1891 he demonstrated a complete end to end system with three phase electrical generators delivering power to three phase induction motors over a three phase electricity transmission system.

1889 America's first alternating current (AC) hydroelectric power generating station was put into service at Willamette Falls, Oregon. Using Westinghouse generators it was also America's first AC transmission system providing single phase power at 4000 Volts which was transmitted to Portland 14 miles away where it was stepped down to 50 Volts for distribution and used to power the street lights.

1889 Walther Hermann Nernst a German physical chemist applied the principles of thermodynamics to the chemical reactions proceeding in a battery. He formulated an equation (now called the Nernst Equation) for calculating the cell voltage taking into account the electrode potentials, the temperature and the concentrations of the active chemicals. It applies to the equilibrium position i.e. no current. This is a special case of the more general Gibbs free energy relationship and is one of the basic formulas used by cell designers to characterise the performance of the cell.

He also showed that in a reversible system the electrical work done is equal to the change in free energy. Also known as the enthalpy.

Nernst stated the Third Law of Thermodynamics that it is impossible to cool a body to absolute zero, when it would have zero entropy, by any finite process. In a closed system undergoing change, entropy is a measure of the amount of energy unavailable for useful work. At absolute zero, when all molecular motion ceases and order is assumed to be complete, entropy is zero.

1890 Dundee born engineer James Alfred Ewing discovers the phenomenon of hysteresis which he named after the Greek "hysteros" meaning "later". He observed that, when a permeable material like soft iron is magnetised by being subjected to an external magnetic field, the induced magnetisation tends to lag behind the magnetising force. If a field is applied to an initially unmagnetised sample and is then removed, the sample retains a residual magnetisation becoming a permanent magnet. He speculated that individual molecules act as magnets, resisting changes in magnetising potential and described the characteristic curve of the magnetic induction B versus the magnetic field H which caused it, calling it a hysteresis loop See diagram. Also known as the BH loop, it was later shown by Steinmetz that the area of the hysteresis loop is proportional to the energy expended in taking the system through a complete magnetisation - demagnetisation cycle. This wasted energy appears as heat and represents a considerable energy loss in alternating-current machines which are subject to cyclic magnetic fields. On the other hand, hysteresis is useful for creating permanent magnets or temporary magnetic memory, once the main method of providing computer Random Access Memory (RAM).

The hysteresis loop is the signature of a magnet. A slender loop indicates a good temporary magnet which has low hysteresis losses and responds readily to a small magnetic field. Temporary magnets (also known as soft magnets) are needed in magnetic circuits subject to cyclic field such as those found in motors, generators, transformers and inductors. A fat hysteresis loop indicates a permanent magnet, or hard magnet, which will remain magnetized after the application and withdrawal of a large magnetic field.

The term "hysteresis" is now used to describe any system in whose response depends not only on its current state, but also upon its past history.

1890 Tesla produced a muli-pole generator suitable for generating a high frequency carrier wave suitable for transmitting radio signals. It had 384 poles and produced a 10 kHz signal.

1891 German born, American mathematician and engineer Charles Proteus (Karl August) Steinmetz developed an empirical law for determining the magnitude of the losses due to the recently discovered phenomenon of magnetic hysteresis (see above) which he published in the magazine, "The Electrical Engineer".

The Hysteresis law for the loss of energy per magnetization cycle per unit volume "W" is given by Steinmetz's equation as:


where Bmax is the maximum flux density, η is the hysteresis coefficient or (a constant depending on the molecular structure and content of the material) and x is the Steinmetz exponent between 1.5 and 2.3, typically 1.6

Steinmetz also provided data on the magnetic characteristics of all magnetic materials then in current use.

As a rule of thumb, when the magnetic flux induced by the alternating current doubles, the hysteresis loss triples. The ability to predict the hysteresis losses for different materials and shapes enabled the design of more efficient machines, a process which had previously been trial and error.

In 1893 Steinmetz developed the phasor method using complex or imaginary number notation for representing the varying currents and voltages in AC circuits. This simple and practical method revolutionised the analysis of AC circuits.

Called the Wizard of Schenectady where he worked for General Electric, Steinmetz also carried out research on lightning phenomena. He was a prolific inventor with over 200 patents to his name including an electric car, the 1917 Dey electric roadster, for which he designed a compact double-rotor motor which was an integral part of the rear axle avoiding the need for a differential.

Steinmetz was physically handicapped with a deformed left leg, humped back, and diminutive stature, only four foot three inches (1.3M) tall, but he was compensated by a brilliant mind, congenial personality and infectious vitality. Raised in poverty, Steinmetz was a lifelong socialist whose early political activities brought him into conflict with the German authorities resulting in his flight from Germany. Throughout his life he applied his considerable energies to helping others.

1891 Another patent for the three-phase electric power generation and transmission system, this one granted to Jonas Wenström a Swedish engineer. His patent was disputed for many years by other claimants, including Tesla (1887), Dobrovolski (1889) and Hopkinson who patented the principle, as applied to DC power transmission, in 1882. It was finally confirmed in 1959, sixty eight years after Wenström died.

1891 American electrical engineer Harry Ward Leonard introduced the motor speed control system which bears his name. For almost a century, until the advent of thyristor controllers, it was the only practical way of providing a variable speed drive system from the fixed frequency mains electricity supply.

1891 Heinrich Hertz, with his Hungarian student Philipp Eduard Anton von Lenard, discovered that cathode rays could penetrate a thin aluminium plate. Because gas could not pass through the foil they surmised that the cathode ray was a wave, publishing their results in 1894. In 1897 J.J. Thomson showed that cathode rays were streams of particles which he called corpuscles and which we now call electrons.

Lenard was awarded the Nobel Prize for Physics in 1905 for his work on cathode rays. He was a strong proponent of the German "Master Race" and became Adolf Hitler's advisor and Chief of "Deutsche Physik" or "Aryan Physics". He claimed that so called "English physics" had stolen their ideas from Germany and denounced Einstein's theory of relativity as a deliberately misleading Jewish fraud perpetrated by "Jewish physics". He was expelled from his post at Heidelberg University by the Allied occupation forces in 1945.

1891 One of the most important inventions in radio telegraphy, the coherer, was demonstrated at the French Academy of Science by physics professor from the Catholic University of Paris, Edouard Eugène Désiré Branly, and the results were published in La Lumière Èlectrique. In 1890 Branly rediscovered the coherer effect, that loose iron or similar filings would coalesce under the influence of an electric or magnetic field dramatically reducing the resistance of a path through the material. Though he was not the first to notice the phenomenon, he was the first to see its potential for detecting radio waves. His device consisted of a small glass tube containing the filings or powder in series with a battery and a galvanometer for indicating changes in the current due to the presence of an electromagnetic field. It was much more sensitive than the spark detector used by Hertz enabling transmissions over much longer distances to be detected and for a decade it became the telegraph industry standard.

Branly's design was improved by Oliver Lodge who added a trembler which shook the filings loose for decohering between signal pulses, readying the device for detecting the next pulse. Unfortunately the coherer was only suitable for detecting the reception of a pulse of radio waves such as Morse code and could not be used for detecting the varying voice signals which, Fessenden showed, could be carried on a radio wave.

Contrary to legend, neither Branly's nor Lodge's coherer was used by Marconi for his first trans-Atlantic radio transmission in 1901. This pioneering communication needed a particularly sensitive detector and this was provided by an Iron-Mercury-Iron Coherer invented in 1899 by Indian physicist Sir Jagadish Chandra Bose of Presidency College, Calcutta. It was an example of an imperfect junction coherer which reset itself after receiving a pulse so there is no need for decohering.

On the basis of his coherer design Branly is revered in France as "The Father of Radio" and some text books even credit him with a Nobel prize for the invention. In fact Branly was nominated three times for the honour but he never actually won the prize.

Prior to Branly and the invention of radio, several others had investigated variations of the coherer effect observed when loosely compacted particles or lightly touching objects were subject to electrical or magnetic fields.

  • In 1866 English engineer Samuel Alfred Varley used the coherer effect in his invention of the lightning bridge for protecting telegraph circuits and their operators. The coherer, containing loosely packed carbon granules in a wooden box, was connected in parallel to the telegraph equipment by a wire running from the telegraph line to the ground. Under normal circumstances, no electrical current could flow though the carbon granules because of their high resistance. But the high voltage between the line and the ground produced by a lightning strike caused the coherer to conduct providing a route for the lighting energy to flow to ground, thus bypassing and protecting the telegraph equipment.
  • In 1884 Italian school teacher Temistocle Calzecchi-Onesti observed that metal filings contained in an insulating tube will conduct an electrical current when influenced by electric or magnetic fields but this property disappears if the tube is shaken. He also noticed that copper filings between two copper plates had two resistance states - conducting when a high voltage was applied between the plates but and non-conducting for low voltages.

1891 German aviation pioneer Otto Lilienthal began a series of over 2000 experimental glider flights in gliders of his own design. Jumping from low hills near Berlin he was able to make flights as far as 820 feet (250 m) demonstrating that flying machines could be possible.

His gliders were similar to modern hang gliders but with a limited range of control made possible by the pilot changing the centre of gravity by shifting his body. Designs were based on Cayley's theories and his own observations of bird flight and he made both monoplane and biplane versions.

In 1889 He published a book Birdflight as the Basis of Aviation outlining his own theories and experiences of flight which has become an aviation classic.

Tragically, in 1896, at the age of 48 while piloting his regular glider he failed to recover from a stall and fell 49 feet (15 m) to the ground, dying from his injuries 36 hours later in hospital.

His last words were "Opfer müssen gebracht werden!" roughly translated as "Victims are necessary" or "Sacrifices must be made".

1891 Russian polymath Vladimir Shukhov patented the first thermal cracking method used in oil refineries for breaking down heavy hydrocarbons in petroleum to increase the percentage of the lighter more useful volatile products such as paraffin (kerosene) and petrol (gasolene). Previously paraffin had been separated in earlier times by the Han Chinese but in more modern times by Drake and others in a process of simple distillation. This gave a welcome boost to the use of the four stroke, spark ignition petrol engine invented by Otto in 1862.

1892 British born American chemist Edward Weston invented and patented the saturated cadmium cell. Known as the Weston Standard Cell, it was adopted as the International Standard for electromotive force (EMF) in 1911 and was used as a calibration standard by the US National Bureau of Standards for almost a century. It had the advantages of being less temperature sensitive than the previous standard, the Latimer Clark Standard Cell which it replaced and of producing a voltage of 1.0183 Volt, conveniently near to one Volt. Similar to Clark's cell it used a Cadmium anode rather than Zinc.

He had revolutionised the electroplating industry in 1875 by replacing the batteries used to provide the current used in the plating process with dynamos which he designed and made himself and in 1886 he developed a practical precision, direct reading, portable instrument to accurately measure electrical current, a device which became the basis for the moving coil voltmeter, ammeter and watt meter.

A prolific inventor Weston held 334 patents.

1892 Eccentric Kentucky melon farmer Nathan B. Stubblefield "demonstrated" wireless telephony using a ground battery or earth battery (first proposed by Bain in 1841), for transmitting signals through the ground. Extravagant claims were made for the applications of the ground battery, from telephony and broadcasting to power generation, but they were never substantiated and Stubblefield, claiming he was swindled, died of starvation, an impoverished recluse. He is honoured in his hometown of Murray, Kentucky as "The Real Father of Radio".

1892 Dutch physicist Hendrik Antoon Lorentz formulates Lorentz Law, a fundamental equation in electrodynamics which gives the force F on a charged particle in an electromagnetic field as the sum of the electrical and magnetic components as follows:

F = qE + qv X B

Where q is the charge on the particle, v is its velocity, E is the electric field and B is the magnetic field. See Diagram of Lorentz Force.

This law describes the principles on which almost all electrical machines and electromechanical devices are based.

Lorentz law complements Maxwell's equations describing electric and magnetic fields and forms the basis of the theory of electrodynamics.

Lorentz developed a mathematical theory of the electron before their existence was proven for which he received the Nobel Prize in 1902

1893 Two German schoolmasters Johann Phillip Ludwig (Julius) Elster and Hans Friedrich Geitel discovered the sensitive photoelectric effect of alkaline metals such as sodium or potassium in vacuum tube at visible light spectrum. They later design the first practical photoelectric cell or "electric eye" which provides a voltage output which varies in relation to the intensity of light impinging upon it. They decline to patent their invention. The photoelectric effect is the basis of all electronic image tubes.

1893 Contract to supply hydroelectric generators to harness the power of Niagara Falls using Tesla's AC system awarded to Westinghouse, signalling the beginning of the end for DC generation and transmission, the end of the Current Wars and a triumph for Tesla. Rival Edison had lined up influential backers including J. P. Morgan, Lord Rothschild, John Jacob Astor IV, W. K. Vanderbilt and initially Lord Kelvin, a proponent of direct current, who headed an international commission to choose the system. After seeing Tesla's AC system which was used to light the 1893 World's Columbian Exposition at Chicago, Kelvin was converted to a be supporter of the AC system.

The system was completed in 1895 with three enormous 5,000 horsepower generators supplying 2,200 Volts for local consumption, stepped up to 11,000 Volts for transmission to Buffalo 22 miles away. The capacity was later increased to 50,000 horsepower with 10 generators and the transmission Voltage increased to 22,000 Volts for longer distance transmission.

1893 French born American railway engineer and aviation pioneer Octave Chanute organised an International Conference on Aerial Navigation at the World's Columbian Exposition in Chicago. He was an enthusiastic and influential promoter of aviation developments and 1894 he published Progress in Flying Machines a survey of all published research into fixed-wing heavier-than-air aviation developments up to that date. The book became a bible for all would-be aviators at the time.

1893 German engineer Rudolf Christian Karl Diesel, born in Paris of Bavarian parents, published a paper entitled "Theorie und Konstruktion eines rationellen Wärmemotors zum Ersatz der Dampfmaschine und der heute bekannten Verbrennungsmotoren" - "Theory and Construction of a Rational Heat-engine to Replace the Steam Engine and Combustion Engines Known Today" in which he described his ideas for the compression ignition internal combustion engine, now known as the Diesel engine. The following year he applied for a patent for the engine. The German company Maschinenfabrik Augsburg Nürnberg AG (MAN) gave him the opportunity to test and develop his ideas.

At the request of the French Government who were looking for locally produced fuels for their African colonies, the Otto Company demonstrated at the Paris Exhibition in 1900, a small Diesel engine running on pea-nut oil, the first bio-diesel. Diesel himself also investigated and promoted the use of alternative fuels in his engines. Compression ignition engines using the Diesel cycle are today taking market share form the more popular spark ignition Otto cycle engines due to their superior efficiency.

Similar compression ignition engines had already been built in 1886 by English inventor Herbert Akroyd-Stuart for which he applied for a patent in 1890 entitled "Improvements in Engines Operated by the Explosion of Mixtures of Combustible Vapour or Gas and Air"

Diesel's inspiration was a modernised version of the ancient Chinese "Firestick" which was used as a cigarette or gas lighter. A piece of tinder was held in a glass tube containing a plunger. When the plunger was forced rapidly into the tube, as in a bicycle pump, the heat of compression would ignite the tinder.

On an apparently normal business trip from Belgium to attend, as guest of honour, the opening of a new Diesel engine factory in England in 1913, Diesel mysteriously disappeared from a cross Channel steamer. His body was recovered from the sea ten days later, but his death has never been satisfactorily explained. Speculation ranges from suicide, (He was thought to be in financial difficulties, though he was about to secure a new royalty stream), through accident, to assassination (On the verge of the First World War, agents of Imperial Germany possibly did not want him to allow the "allies" access to his patents).

See also Heat engines.

1894 The first ever radio signal was sent 55 metres from one building to another in Oxford during the 1894 meeting at the British Association for the Advancement of Science about the work of Hertz who had died earlier that year. The lecture and demonstration were given by British physicist Oliver Joseph Lodge who arranged the transmission of the Morse code like signals which were transmitted by electrical engineer Alexander Muirhead and detected by Lodge using a modified Branly coherer rather than Hertz's spark gap. The sender used a telegraph key to send a pulse and the coherer in the receiver caused a bell to ring. It was just like a telegraph link but without the interconnecting wire. Lodge later formed a business partnership with Muirhead to commercialise a number of fundamental radio technology inventions which they had patented.

In 1911 they sold their patents, one of which was Lodge's patent for the tuned circuit to radio pioneer Guglielmo Marconi.

Lodge was knighted for his contribution to physics but much of his later life was devoted to his interest in the paranormal, "life after death" and spiritualism about which he wrote several books.


1895 German physicist Wilhelm Conrad Röntgen experimenting with a Crookes tube accidentally discovered X-rays, high frequency electromagnetic radiation, while investigating the glow from the cathode rays. He gave his preliminary report "Uber eine neue Art von Strahlen" to the president of the Wurzburg Physical-Medical Society, accompanied by experimental radiographs and by the image of his wife's hand. Within three years, every major medical institution in the world was using X-rays. Röntgen, who won the first Nobel prize in physics in 1901, declined to seek patents or proprietary claims on the use of X-rays.

Röntgen used a very high voltage to accelerate the electrons in a high speed electron beam and X-rays were produced when the beam was suddenly decelerated when it hit the target electrode. These rays had a continuous frequency spectrum and are now called bremsstrahlung radiation, or "braking radiation".

Characteristic X-rays on the other hand have a spectrum with definite energy levels which are produced when electrons make transitions between characteristic atomic energy levels in heavy elements.

X-ray technology is now widely used in materials science. See Bragg (1912)

1895 French physicist Pierre Curie discovered that for paramagnetic materials such as aluminum or platinum which become magnetised in a magnetic field but whose magnetism disappears when the field is removed, their magnetic coefficients of attraction vary in inverse proportion to the absolute temperature -- Curie's Law. He also showed that when ferromagnetic materials which tend to retain their magnetic properties, such as iron and nickel, are heated to an elevated temperature, above a characteristic temperature dependent on the material, now called the Curie point or Curie temperature they lose all of their magnetic properties.

The magnetic force associated with these materials is determined by the magnetic moment, a dipole moment within an atom which originates from the angular momentum and spin of electrons producing a tiny magnetic field. The magnetic fields are normally randomly oriented so that their overall fields cancel out, but small groups of atoms may be aligned with their fields in parallel reinforcing eachother in so called magnetic domains with a distinct magnetic orientation. When placed in a magnetic field, the orientation of these domains tends to line up in the direction of the applied field.

In the case of paramagnetic materials, the magnetic moment is quite feeble and the domains return to a random distribution once the external field is removed.

Ferromagnetic materials however have a much stronger magnetic moment and tend to retain their magnetic properties up to the Curie temperature (770 °C or 1,418 °F for iron) at which point the thermal agitation of the atoms causes the domains to become randomly oriented once more thus the material loses its overall magnetic moment. Conversely if ferromagnetic materials with no retained magnetic moment are heated to a temperature above the Curie point and allowed to cool in an external magnetic field, at the Curie point the magnetic domains will tend to line up spontaneously with the field and will retain their magnetic moment once the field is removed.

Curie also showed that there is no significant magnetic effect of temperature on diamagnetic materials such as copper, mercury and gold.

1895 Alexandr Popov, an instructor at the Russian Imperial Navy's torpedo school, experimented with a variety of antennas (aerials) to capture electromagnetic radiation from lightning discharges. His receiver consisted of a coherer between an aerial wire connected to a tall mast and an earth (ground) wire connected to water pipes to detect the radiation, he successfully proved that the discharge emits electromagnetic waves. His experiment did not include a transmitter.

In 1890 he had repeated Hertz' experiments for the benefit of his students and in 1896, at a meeting of the Russian Physical-Chemical Society, he repeated Lodge's 1894 demonstration of radio signalling by sending the Morse coded message "Heinrich Hertz" over a radio link. Like Lodge, Popov was more interested in pursuing theoretical physics than in commercialising the idea, leaving the door open to the less technically competent but more commercially astute Marconi. (See following item). In later years the existence of these experiments was used to justify the claim by Popov's supporters that he was "The Father of Radio".

1896 Inspired by Hertz, 22 year old Italian Marchese Guglielmo Marconi, son of the Irish-born heiress to the Jameson whiskey fortune, was granted his first patent (in England) for radio telegraphy using Hertzian waves. This was claimed to be the first application of radio waves and the first to show that practical radio communications were possible. But Marconi had basically just patented the system demonstrated by Lodge two years earlier, and the principle of radio communications. Though he had been helped by William Preece, the Chief Engineer of the British Post Office, and his staff, Marconi himself added little to the system which was the radio equivalent of Morse's telegraph, which just switched the radio wave on and off in "dots and dashes", and did not carry voice signals. Because Marconi's "invention" was enclosed in a box, the patent office did not consider the technology to be in the public domain and so granted the patent. Lodge and Preece had been kept in the dark about the patent application and felt deceived.

It was Fessenden who first carried voices over the radio waves ten years later. Marconi was a great promoter, he developed transmitters, receivers and antennas and his telegraph systems were soon in use throughout the world, spanning the Atlantic in 1901, and earning him fame and fortune. He was awarded the Nobel prize for physics in 1909.

See also Wireless Wonders.

1896 American engineer William W. Jacques developed a carbon battery producing electricity directly from coal. 100 cells with carbon electrodes and alkaline electrolyte were placed on top of a coal fired furnace that kept the electrolyte temperature between 400-500 °C and air was injected into the electrolyte to react, he thought, with the carbon electrodes. The output was measured as 16 Amps at 90 Volts. Initially, Jacques claimed an 82 percent efficiency for his battery, but he had failed to account for the heat energy used in the furnace and the energy used to drive an air pump. The real efficiency was a meager 8 percent. Further research demonstrated that the current generated by his apparatus was not obtained through electrochemical action, but rather through thermoelectric action.

1896 Antoine Henri Becquerel discovered radioactivity when Uranium crystals wrapped in paper and left in a drawer with photographic plates created an image of the crystals on the plates. Radioactivity, we now know, is the spontaneous breakdown or decay of unstable atomic nuclei resulting in the emission of radiation which may be alpha particles (Helium nuclei), beta particles (electrons), gamma rays (high energy electromagnetic radiation), or the yet unknown nucleons (neutrons or protons resulting from spontaneous nuclear fission - a splitting of the atom). At the time however the nature of these mysterious rays was not known and it was several years before Rutherford and others were able to identify the content of the radiation.

Radioactivity can come from the decay of naturally occurring radioisotopes in a process now known as beta decay. Nuclear batteries are designed to make use of the radiated energy of certain radioactive isotopes by converting it into electrical energy.

Becquerel came from a distinguished family of scholars and scientists. His father, Alexandre-Edmond Becquerel, was a Professor of Applied Physics, discovered the photovoltaic effect and had done research on solar radiation and on phosphorescence, while his grandfather, Antoine César Becquerel, had been a Fellow of the Royal Society and invented a non polarising battery and an electrolytic method for extracting metals from their ores.

1896 In the USA, the flashlight or torch was invented by David Misell. The original versions were designed to attach to a tie or scarf and were sold by a Russian immigrant, Conrad Hubert in his novelty shop where Misell went to work. Although portable battery powered lamps had been in use in the UK since 1881 where they were patented by Burr and Scott, the first flashlight as we know it today introduced by Hubert in 1898. It was designed by Misell and was powered by a "D" cell which, with the light bulb and a rough brass reflector, was contained in a paper tube. Hubert went on to found Ever Ready and patents for subsequent flashlights although designed by Misell were awarded to Hubert.

The invention of the tungsten filament lamp by Coolidge in 1910 greatly improved the performance of the torch which in turn created a growing market for batteries, popularising the "D" cell format we still use today.

1896 H. J. Dowsing patented the electric starter which he fitted to a modified Benz motor car purchased from maker Walter Arnold who made them under licence as the Arnold Sociable in East Peckham, Kent. Dowsing's starter consisted of a dynamotor, coupled to a flywheel, which acted as a dynamo to charge the battery and as a motor when needed to start the engine, an idea recently rediscovered as the integrated starter alternator (ISA). The first production electric self-starter was produced by Dechamps in Belgium in 1902.

1896 American astronomer, inventor, secretary of the Smithsonian Institution, professor Samuel Pierpoint Langley successfully launched a series of unmanned gliders to demonstrate the potential for controlled flight in a heavier than air machine. They were launched from a boat on the Potomac River and one of these flew over 4000 feet (1220 m) while another covered 5000 feet (1525 m). To test his theories and designs he constructed a version of Cayley's "whirling-arm apparatus" to measure the aerodynamic forces on models as they were propelled at high speed through the air. He investigated various wing profiles and showed that even a brass plate could be kept aloft if its speed through the air was high enough from which he concluded that a heavier than air machine would be viable.

Based on the success of his models, in 1898 Langley received a grant of $50,000 from the US War Department and a further $20,000 from the Smithsonian to develop a manned airplane, which he called an "aerodrome" (Greek - aeros "air" and dromos, "road" or "course").

To save weight, Langley's airplane had no landing gear so it was designed for catapult launching and landing over water. It had pitch and yaw control but no roll control and a 50 horsepower engine, more than four times the power of the engine used in the Wright Flyer. The airframe of the plane was very flimsy and the engine was very heavy, - too heavy. It was ready in 1903 but it made only two flights, one in on October 7 and one on December 8, both of which ended in crashes before the plane got airborne. In the second crash the plane broke up dumping the pilot on the Potomac leaving half of the plane still on the launching boat and the other half in the river. With the benefit of perfect hindsight, the army, who had paid for the plane and witnessed the tests, announced that the reason for the failure was that the propellers were too small.

The newspapers revelled in Langley's misfortune, particularly the New York Times. After the first crash of what they called Langley's "airship", they offered their opinion that it would be at least 1000 years before man could devise a flying machine, basing their prediction on the principles of evolution. After the second crash they advised Langley to give up and stick to his academic pursuits.

One week later, the Wright brothers made the first successful controlled flight of a heavier than air machine.

NASA's Langley Research Centre at Hampton, Virginia is named in Langley's honour.

Langley also invented the bolometer in 1878.

1897 British physicist Joseph John (J J) Thomson working at the Cavendish Laboratory in Cambridge investigating the affect of magnetic fields on cathode rays in a Crookes tube discovered the electron and calculated the ratio between its charge and its mass, the e/m ratio. He determined that they were identical particles no matter what metal had emitted them and that they were the universal carriers of electricity and a basic constituent of matter. He also calculated the velocity of the electron in the cathode ray to be 1/10 of the speed of light. He knew that the electrons were emitted by the atom but was unaware of their original distribution within the atom and assumed that they were randomly distributed within the mass of the atom like raisins in a cake or plums in a pudding. His model of the atom became known as the plum pudding model but was later shown to be incorrect.

J.J. Thomson was awarded the Nobel prize in 1906 for his studies on the conduction of electricity through gases and for the discovery of the electron and his pioneering work on the structure of the atom.

At the time there was great rivalry between German researchers who believed cathode rays to be waves and their British counterparts who believed them to be particles. In one of the greatest ironies of modern physics J.J. Thomson was awarded the Nobel Prize for showing that the electron is a particle, while his son, George Paget Thomson later received the Nobel prize for proving that the electron was in fact a wave.

Seven of Thomson's students went on to gain Nobel prizes in their own right.

Thomson died in 1940 and in his lifetime he never drove a car or travelled in an aeroplane. He had a passion for nature and said that if he had to live his life over again he would be a botanist.

Ever since Faraday published his work on the magnitude of the weights of the products of electrolysis in 1833, experimenters had postulated the idea that electric current was carried by corpuscles or particles but none had been able to isolate or describe such particles. By the late 1890's however, several other investigators working contemporaneously with Thomson had identified the charged particle we now call the electron and calculated the e/m ratio just as Thomson did in April 1897. These included Pieter Zeeman at the University of Leiden who in 1896 observed the spreading of spectral lines caused by the influence of a magnetic field and concluded that the light waves were produced by the movement of ions. The theory was superseded to take account of electron spin properties which were demonstrated by Stern and Gerlach in 1922. See diagram of the Zeeman effect. From the experiment he was able to calculate the e/m ratio. At the same time, each working independently with cathode rays, Emil Weichert at the University of Köningsburg, Walter Kaufmann at the University of Berlin and Philipp Lenard an assistant of Heinrich Hertz carrying on Hertz' experiments after his death, all published similar results for the value of the e/m ratio early in 1897. It was Thomson however who identified the electron as a sub atomic particle, while the others were hampered by trying to reconcile the evidence of a particle with the notion of the aether.

See also spectral ine spreading by the Stark effect.

In 1902 Zeeman shared the Nobel Prize for Physics (only the second time it had been awarded for physics) with his mentor Lorentz who had predicted the Zeeman effect.

History is kind to the winners of Nobel prizes. Once conferred, the other participants in the race are forgotten.

1897 The first oscilloscope using a cathode ray tube (CRT) scanning device was invented by the German scientist Karl Ferdinand Braun. He made many contributions to radio technology including antennas and detectors. He was awarded the Nobel prize with Marconi in 1909 for this work. During the First World War he was interned by the US government as an enemy alien and died before the war ended.

1897 Regenerative braking first used on a car to recharge the battery by M. A. Darracq in Paris.

1897 Russian mathematics teacher, Konstantin Eduardovich Tsiolkovsky, built a wind tunnel in his apartment which he used to explore aerodynamics and the drag characteristics of different shapes. During the same year he also developed the fundamental Theories of Rocket Motion which he published as "The Exploration of Cosmic Space by Means of Reaction Devices". In it he showed that a rocket's velocity is proportional to its effective exhaust velocity and he defined the Specific Impulse, which became the standard measure for comparing the energy produced by rocket engines and propellants.

He defined the Specific Impulse (I), expressed in seconds, as follows:

I = F / (dm/dt)

Where F is the rocket thrust in pounds and dm/dt is the propellant consumption in pounds per second.

Alternatively this can be written in terms of the rocket exhaust velocity ve as follows:

I = ve / g

Where g is the acceleration due to gravity (32 f/sec/sec)

He also showed that the change δv in velocity of a rocket as it consumes its fuel is given by:

δv = veLn(m0/m1)

Where ve is the exhaust velocity, m0 is the initial total mass, including propellant, m1 is the final total mass and ln is the natural logarithmic function.

This is known as the Tsiolkovsky Equation

It can also be expressed in terms of the Specific Impulse of the fuel as follows:

δv = I.g

With these relationships he was able to compare the effectiveness of different fuels, to calculate thrust and flight velocity as a function of fuel consumption and to show the influence of gravity during vertical ascents.

In 1903 he published a summary of studies he had carried out into liquid fuelled rockets and the optimum shape for rocket exhaust nozzles and he proposed the ideas of fuel pumping systems, regenerative cooling and directional control by means of rudders in the exhaust stream all of which were first successfully introduced on the German V-2 rocket forty years later.

In 1911 he confirmed the Earth's Escape Velocity to be 25,000 miles per hour and calculated the Orbital Velocity for Earth Satellites to be 17,800 miles per hour. See also Entering Space.

He had a keen interest in space travel and published many works on space stations and life support systems. He also developed the concept of the Multi-stage Rocket, which he called a "rocket train", to achieve higher velocity and range with the same initial vehicle weight, payload weight and propellant capacity or alternatively to carry a greater payload with a smaller initial weight. By jettisoning the propellant tanks and engines of the first stages once the propellant is used up, the later stages to not have to waste energy in accelerating a useless mass.

Tsiolkovsky's early works were the first academic studies on rocketry but unfortunately they were published in Russian and at the time they did not achieve a high circulation in the international scientific community. Despite his interest and the wide ranging scope of his contribution to the science, he never built any rockets.

See also Rocket propulsion

1897 German researcher W. Peukert discovered that the faster a battery is discharged the lower its available capacity, a phenomenon for which he developed the empirical law C = IT known as the Peukert Equation where "C" is the theoretical capacity of the battery expressed in amp hours, "I" is the current, "T" is time, and "n" is the Peukert Number, a constant for the given battery. A similar phenomenon occurs when a battery is charged. See also charging times for an explanation and a beer analogy.

1898 Danish telephone engineer Valdemar Poulsen patented the Telegraphone, the first magnetic recording and playback apparatus. It used a magnetised wire as the recording medium.

1898 The Proton discovered by German physicist Wilhelm Wien. Using an apparatus designed by Goldstein which generated canal rays of positively charged particles he determined that canal rays were streams of protons with mass equal to the mass of a Hydrogen atom. Rutherford later coined the word proton in 1917.

Wien also discovered the inverse relationship between the wavelength of the peak of the emission of a black body and its temperature now called Wien's Law. He was awarded the Nobel Prize in 1911 for his work on Black Body Radiation.

1898 Oliver Lodge patented the principle of tuned circuits which he called "syntonic tuning" for generating and selecting particular radio frequencies. This is the basis of selecting a single desired radio station from all those which are transmitting by tuning the receiver to the transmitter. Not only was this more efficient, it was fundamental to the orderly use of the radio spectrum and the establishment of practical radio communications systems which did not interfere with eachother.

1898 Pierre and Marie Sklodowska Curie discovered Radium named from the Latin "radius" meaning "ray" and Polonium which Marie named after her native Poland. With very limited resources, during the course of four years, the Curies refined 8 tonnes of waste pitchblende to produce 1 gram (0.04 ounces)of pure Radium Chloride. (It was not until 1911 that she was able to isolate pure Radium). Radium is over one million times more radioactive than the same mass of Uranium and one gram of Radium releases 4000 kilo joules (1.11 KWh) of energy per year. In 1900 they showed that beta rays and cathode rays are identical. Unaware at the time of the dangers of radiation in 1903 they both began to show signs of radiation sickness. Marie shared the 1903 Nobel Prize for Physics with her husband Pierre and Henri Becquerel for the investigation of radioactivity, a phenomenon which she named. In 1906 Pierre was unfortunately killed when he was run over by a horse drawn cart. Marie continued their investigations and in 1911 was awarded a second Nobel Prize, this time for Chemistry for her discovery of two new elements.

Despite her achievements and her two Nobel prizes, she was rejected by the French Academy of Sciences when seat for a physicist became vacant. During her life she worked tirelessly for humanitarian causes and the use of X-rays and radioactivity in medical research, refusing to patent any of her ideas. She died of leukaemia caused by prolonged exposure to radioactivity. Her laboratory notebooks are still considered too radioactive to handle and photographic films, when placed between the pages, show the images of Madame Curie's radioactive fingerprints when developed. A year after her death, her daughter Irene won the family's third Nobel Prize.

1899 First patent on Nickel Cadmium rechargeable cells using alkaline chemistry taken out by Waldemar Jungner of Sweden. The first direct competitor to the Lead acid battery.

1899 The world land speed record of 68 mph was set by a Belgian built electric car, the "Jamais Contente", designed and driven by Camille Jénatzy. The first to exceed 100 kph, his cigar shaped car was powered by two 80 cell Fulmen Lead acid batteries supplying two twelve volt, 25 kilowatt motors, integral with the rear axle, driving the rear wheels directly.

Jénatzy, known as the Red Devil because of his red beard, was a famous racing driver at the time when racing was very dangerous, however his life was ended at his country estate rather than on the race track when, hosting a shooting party, he sneaked into the woods to imitate a roaring bear and was shot by one of his friends.

1899 Young German engineer Ferdinand Porsche, working at the Jacob Lohner Company, built the first Hybrid Electric Vehicle (HEV), a series hybrid, optimised for simplicity and efficiency. It used a petrol engine rotating at optimum, constant speed to drive a dynamo which charged a bank of batteries which in turn provided power to hub mounted electric motors in the front wheels. 300 Lohner Porsches were produced.

1899 Serbian immigrant Mihajlo (Michael) Idvorski Pupin filed for a patent (granted in 1900) for the Pupin inductive loading coils which are used to cancel out distortion due to the distributed capacitance in long transmission lines. The idea which was originally proposed, but not patented, in 1887 by Oliver Heaviside made Pupin very wealthy and destroyed Heaviside. Far from recognising his debt to Heaviside, he chose instead to belittle his contribution.

Not content with stealing Heaviside's ideas, Pupin played the same trick on Oliver Lodge who patented the tuned circuit for selecting radio waves in 1898. In his autobiography Pupin disingenuously claimed to have invented the tuned circuit in 1892 after being inspired by the way Serbian bagpipers tuned their pipes. Strangely Pupin did not patent the idea at the time but he did receive a patent or "Electrical transmission by resonance circuits" in 1900.

Pupin arrived in the United States as a young penniless immigrant. He studied at Columbia University where he made improvements to X-ray photography and radio wave detection eventually rising to be emeritus professor.

1899 Charles H. Duell Commissioner in the US Office of Patents announced "Everything that can be invented has been invented"

1899 Working at McGill University in Montreal on Becquerel's mysterious rays resulting from the spontaneous disintegration of the Uranium atom, New Zealand physicist Ernest Rutherford, assisted by English chemist Frederick Soddy, investigated further Becquerel's beta decay and discovered two kinds of "rays" (actually particles) emanating from the Uranium, one of which he called the alpha rays, could be absorbed by a sheet of writing paper. The other which he called beta rays was one hundred times more penetrating but could be stopped by a thin sheet of aluminium.

Meanwhile in 1900, French physicist Paul Ulrich Villard found that Radium emitted some far more penetrating radiation, which he named gamma rays. These rays could penetrate several feet of concrete.

Still undetected at that time were the neutral neutrons discovered in 1932 by British physicist Chadwick in experiments with light metals such as Beryllium and the neutron rays from the natural decay of Uranium discovered in 1940 by Russian physicists Flyorov and Petrzhak.

It was still some time before the properties of all these different rays could be determined.

  • By 1900 Becquerel succeeded in deflecting the beta rays with a magnetic field proving that the rays were in fact streams of charged particles. He also measured the e/m ratio of the particles which turned out to be close to that of cathode rays suggesting that the beta rays were in fact streams of electrons.
  • It was not until 1903 that Rutherford was able to deflect the alpha rays and it was 1905 before he could measure the e/m ratio. His results showed that the rays were in fact particles with the opposite charge from an electron. He concluded that if the charge on an alpha particle was the same as that on a Hydrogen ion, the mass of the alpha was approximately twice that of the hydrogen atom. In 1908, he finally established that the alpha particles were Helium atoms with two electrons missing, carrying a positive charge of + 2 e , and having mass four times that of the Hydrogen atom.
  • Gamma rays were not deflected by a magnetic field which showed them to be rays and not particles. They were found to be similar to X-rays, but with much shorter wavelength. This was not settled until 1914, when Rutherford observed them to be reflected from crystal surfaces.
  • Neutron "rays" were difficult to detect since neutrons carry no charge. The existence of neutrons resulting from the disintegration of Uranium was first noticed by Hahn and Strassmann in 1938 among the products of the induced fission of Uranium atoms when bombarded by other neutrons. Two years later Flyorov and Petrzhak confirmed that neutrons were also produced by spontaneous fission of Uranium.

More 1900 events - continued after "THEME"

THEME: The Development of Quantum Physics

See also the Standard Model of Particle Physics and the Timeline of Theories, Predictions and Discoveries

1900 German physicist Max Planck announced the basis of what is now known as quantum theory, that the energy emitted by a radiating body could only take on discrete values or quanta. Planck's concept of energy quanta conflicted fundamentally with all past classical physics theory and eventually gave birth to the particle theory of light as later explained by Albert Einstein. Although its importance was not recognised at the time, quantum theory created a revolution in physics. Planck was driven to introduce it strictly by the force of his logic; he was, as one historian put it, a reluctant revolutionary.

The energy E in a quantum of light, now called a photon, or resonator of frequency f is hf

Where h is a universal constant equal to 6.63 X 10-34 Joule seconds (Js), now called Planck's constant.

The relationship:   E=hf   is known as Planck's Law.

(Alternatively:   E=hc/λ   where λ is the wavelength of the radiation and c is the speed of light.)

Planck was awarded a Nobel prize in 1918 for his work on quantum theory.

See more about Photon Energy

Planck's personal life was a tragic one. His first wife died early leaving Planck with two sons and twin daughters. The elder son was killed in action in 1916 in the First World War. Both of his daughters died in childbirth. World War II brought further tragedy. Planck's house in Berlin containing his technical papers was completely destroyed by bombs in 1944. Far worse, his younger son died while being tortured by the Gestapo after being implicated in the attempt made on Hitler's life in 1944. Planck died in 1947 at the age of 88.

1905 Annus Mirabilis - Einstein's miraculous year. In those twelve months, 25 year old German born, Albert Einstein, working as a "technical expert third class" patent clerk at the Swiss Patent Office in Bern, shook the foundations of classical physics with five great papers that established him as the world's leading physicist.

  • Einstein first challenged the wave theory of light, suggesting that light could also be regarded as a collection of particles, now called photons whose energy is proportional to the frequency (colour) of the radiation. A photon of electromagnetic energy is considered to be a discrete particle with zero mass and no electric charge and having an indefinitely long lifetime. This helped Planck's revolutionary quantum theory to gain acceptance.
  • See also Hertz photoelectric effect (1887).

  • The second paper, Einstein's doctoral dissertation, shows how to calculate Avogadro's number and the size of molecules and surprisingly is Einstein's most cited work.

  • The third paper concerned the Brownian motion of small particles suspended in a liquid for which Einstein derived an equation for the mean free path of the particles as a function of the time. See also Brownian Motion (1827)

  • In his fourth paper "On the Electrodynamics of Moving Bodies", Einstein introduced for the first time, the concept of Special Relativity. He used it to explain inconsistencies which resulted when Maxwell's equations were used to describe the motions of moving magnets and also to explain the absence, as demonstrated by the Michelson-Morley experiment, of the so called luminiferous aether previously thought essential for the transmission of light waves.
  • It was based on two postulates:

    • The laws of physics are invariant (i.e., identical) in all inertial systems (i.e., frames of reference, such as space and time, moving at a constant speed relative to each other, and not subject to acceleration).
    • The speed of light in a vacuum is the same in all frames of reference, regardless of the motion of the light source or the observers.

    • To this must be added the inference from Galileo's observation that it is not possible to detect whether a ship is moving (at a constant speed) by an experiment from inside the ship. This implies that since are no fixed reference points in space, it is not possible to identify absolute motion. All motion is realtive and it is only possible to detect relative motion between inertial frames of reference.

    These condtions implied that time was variable and that absolute time had to be replaced by a new absolute: the speed of light introducing a new framework for all of physics.

    This further implied that the time and space experienced by moving bodies become distorted according to the following rules:

    For bodies with an invariant or static length L' and invariant or rest mass m' moving with constant velocity v relative to an observer:

    • The time t' measured by a clock on a moving body (the dilated time), compared with the time t measured by a static observer's clock during the same period, becomes dilated by a factor γ (gamma), known as the Lorentz transformation (but see Note below) equal to 1/√(1 - v2/c2) where c is the velocity of light, so that:
    • t = t'/√(1 - v2/c2)

      Thus a fast-moving clock will tick at a slower rate than a stationary clock and it therefore runs more slowly. This means that a clock moving with the body measures a shorter time than the static clock during the same period and an observer moving with the body will correspondingly also age more slowly than a static observer.

      (The time t is simply calculated from the extra distance the light appears to travel for the moving observer travelling with velocity v as observed by the fixed observer during the time t' assuming a fixed speed of light c.)

    • At the same time, the length L of the moving body contracts by a factor 1/γ, becoming shorter in the direction of travel, with the contraction given by:
    • L = L'√(1 - v2/c2)

    • Similarly, the so called relativistic mass m of a moving body increases with the velocity and is given by:
    • m = m'/√(1 - v2/c2)

    These adjustments are almost imperceptible in daily life where our movements rarely, if ever, reach 1000 km/h (0.28 m/s) compared with the speed of light of 299,792,488 m/s. However in particle physics experiments when particles may be accelerated to over 99.9% of the speed of light, these adjustments due to relativity are highly significant. Two examples:

    • A passenger on an airplane travelling at 920 Kph (572 Mph) for 8 hours as measured by an observer on the ground, will land 0.000,0003 seconds earlier than the sheduled 8 hours according to the time indicated by the passenger's own wristwatch and will have aged by one third of a microsecond less than the static observer.
    • A traveller on a spaceship travelling at 80% of the speed of light on a round trip of 6 years as measured by the spaceship's clock (and his body clock) will find that everybody on Earth will be 10 years older on his return.

    An observer positioned on the moving body, and moving with it, will however have a relative velocity of v=0 with respect to the moving body. In this case γ will be equal to one so that the observer will not witness any time dilations, length contractions or increases in mass and will experience time t', length L' and mass m' just as if the body had been stationary.


    The prior existance of the Lorentz transformation might imply that Lorentz anticipated or discovered special relativity before Einstein. In fact it was a mathematical expression developed by Lorentz to represent a completely different physical phenomenon which turned out to be an erroneous hypothesis. Neverthless, the name has endured and it is a coincidence that Einstein's relativistic relationships can be represented by the same mathematical expression.

  • In his last paper in 1905, Einstein asserted the equivalence of mass and energy with the expression E = mc2.
  • He used his special relativity theory to show that the energy of radiation such as light bursts emanating from a body will depend on its frame of reference. Assuming a light burst carries energy E from a body in a stationary frame of reference, the same light burst, from a body in a moving frame of reference with velocity v, will be γE, so that the difference in energy is E(γ-1). Einstein showed that to a very close approximation that E(γ-1) ≈ ½ E v2/c2. But since energy must be conserved, this energy difference must arise from the difference in the kinetic energies of the object in the two frames of reference which is ½mv2. Thus:

    E(γ-1) ≈ ½ E v2/c2 = ½mv2

    Since v does not change, this expression reduces to:

    E/c2 = m (the change of mass)    or    E=mc2

    This shows that the energy of the light burst comes from the reduction in the mass of the object.

By 1906 Einstein was still working at the Patent Office where, despite his achievements, he was promoted only to "technical expert second class".

It was for the discovery of the law of the photoelectric effect that Einstein eventually received the Nobel prize in 1921, not for the theory of relativity or E = mc2 as is popularly supposed.

In 1915 Einstein published a paper on General Relativity (subsequently modified several times) in which he expanded on his theory of special relativity to include the effects of gravity. He recognised that local experience of acceleration and gravity were the same, a phenomenon which he called the equivalence principle. By replacing special relativity's relative frames of reference representing bodies with constant velocity with frames representing constant acceleration, he thus brought the effects of gravity into a more universal theory. This brought "time" into the equation and required the unfamiliar concept of four dimensional mathematics to represent the interrelationships beteween the three dimensions for the familiar "3D" orthogonal axes of space and the new dimension of time.

Einstein's former teacher at Zurich Polytechnic, German mathematician Hermann Minkowski showed in 1907 that the special theory of relativity, could be understood geometrically as a theory of multi-dimensional "spacetime" where space and time are merged together in a single entity which became known as "Minkowski spacetime". This enabled the properties of space and time to be measured in the same units so that they could be represented in a single spacetime grid diagram. However this formal diagram, while helpful, still did not provide a realistic illustration of the effects of the forces involved.

See an example of a Minkowski Spacetime Diagram

In 1912 Einstein sought the help of Marcel Grossmann, the head of the mathematics department at the Zurich Polytechnic, to find a better visual analogy which fully described the physics of general relativity. Grossman pointed out that the problem was due to the limitations of the familiar Euclidean geometry of flat space to illustrate curved surfaces and their effects and that this problem had already been solved in 1854 by German mathematician Georg Bernhard Riemann.

Riemann had devised a new geometry based on the extended use of vectors for calculating distances on curved surfaces. Euclidean vectors normally describe a quantity acting in one dimension with two components, a magnitude and a direction. Riemann extended this concept to quantities acting in multiple dimensions so that a vector acting in three dimensions would have six independent components and a quantity acting in four dimensions would have 16 components. This was called a metric tensor. (A tensor can be considered to be a multi-dimensional matrix)

Thus he showed that the properties of four dimensional space can easily be represented in an abstract mathematical form by tensors (easily understood at least by expert mathematicians and physicists). This enabled Einstein to develop a visual analogy known as the spacetime grid or metric which better illustrates the physics.

See an example of the Spacetime Grid showing the warping of space due to the influence of the massive stars and planets in the Universe.

Einstein also predicted that a consequence of the distortion of spacetime is the gravitational deflection of light as it passes a massive celestial object such as a star. This effect is called gravitational lensing. If this could be demonstrated, it would verify his general relativity theory.

In 1917 Einstein's challenge was taken up by Frank Watson Dyson the British Astronomer Royal, and astrophysicist Arthur Stanley Eddington who together devised an experiment to investigate the issue. Development of the plan was not easy since it involved cooperation between scientists from Britain and Germany, two nations which were then at war with eachother.

The method was to observe the light from the stars in the part of the sky surrounding the Sun. But because the intense light from the Sun washes out the light from the stars, they would have to wait until the occurrence of a total solar eclipse when the Sun is masked the moon so that the light from the surrounding stars would be visible in the darkness.

The first opportunity was the predicted solar eclipse of 19th May 1919 which could be observed in Africa and Brazil. Eddington took a team to the island of Principe, off the west coast of Africa, and Charles Rundle Davidson from the Grenwich observatory took another team to the city of Sobral in Brazil to maximise their chances of success in case of adverse weather conditions.

The measurements were indeed hampered by the weather as had been feared but they went ahead anyway.

It rained on Principe on the morning of the eclipse and Eddington was only able to capture images through fleeting clouds. He managed to take 16 photographic plates but later discovered that only two of these contained enough stars to tell whether their light might have been bent or not and unfortunately they were blurred. Nevertheless he was convinced that they confirmed the expected displacement of their images by the Sun.

At the same time, although it was unusually cloudy in Sobral, Davidson was slightly luckier when the sky cleared one minute before the totality of the eclipse. Unfortunately 19 images from his main telescope were also blurred and out of focus because the heat of the Sun had distorted the telescope mirror, but happily he obtained several relevant star images from a back-up telescope he had taken with him.

Despite the imperfections in the images the scientific community considered that they had confirmed Einstein's predictions.

Eddington announced his findings at the Royal Society on November. 6, 1919 and the spectacular news made the front page of most major newspapers around the world making Einstein and his theory of general relativity world-famous.

Similar experiments in subsequent years have confirmed Einstein's theory. In 2017 the first observation of the apparent displacement of a star due to bending of its light by another celestial body other than our Sun was made by the Hubble telescope. It measured the displacement of light caused by the chance alignment of two stars from outside our solar system with the line of sight of the telescope.

See a diagram of The Gavitational Deflection of Light as seen by the Hubble telescope

In 1924 Indian physicist Satyendra N. Bose working at the University of Dhaka wrote a paper entitled "Planck's Law and Hypothesis of Light Quanta" outlining an alternative derivation of Planck's Radiation Law which he sent to Einstein asking for his help in publishing it. Einstein was intrigued and translated Bose's paper into German, and had it published in Zeitschrift für Physik under Bose's name. Over the next few months Einstein clarified and expanded Bose's work and used his theories to investigate and develop what became known as the Bose-Einstein statistics which defined the possible quantum energy states of photon clouds. He compared the possible energy states of a cloud of identical matter particles such as electrons and a similar, though theoretical, cloud of identical light particles (photons) and concluded that the two particle types would behave differently. This was one year before, but consistent with Pauli's current notion that matter particles obeyed the exclusion principle, and consequently had fewer degrees of freedom than the photons which did not suffer from the same constraint and would therefor have different properties.

In subsequent years, the special case of the photons which had radiation-like properties and were characterised by having integer spin was extended to a general class of all particles with zero or integer spin which possess similar properties. Paul Dirac named this class of particles "bosons" in honour of Satyendra Bose.

See more about bosons.

See also Fermi-Dirac statistics.

See also Einstein's Refrigerator.

Einstein once said "The hardest thing in this world to understand are income taxes".

1909 Cambridge undergraduate student Geoffrey I. Taylor, investigating the corpuscular nature of light, repeated Young's double-slit experiment using photons as the light source. A very low intensity light source, further attenuated by darkened glass plates, was used to produce a beam of individual photons to illuminate the target. It took three months to transmit sufficient photons to produce a photographic image of the light fringes on the screen. While the photon source was not perfect, the interference fringes produced were similar to those produced by Young, demonstrating the interference between quantum particles, confirming the corpuscluar theory of light and the principle of wave-particle duality and suggesting the possible wave nature of matter. The oddest result however was that the interference occurs even if only one particle is fired at a time. A single particle seems somehow to pass through both slits at the same time, interfering with itself. This behaviour is now known as a superposition of states. His results were later confirmed with more precise equipment by others. See diagram of Young's and Taylor's double-slit experiments.

One important conclusion was that a particle seems to behave like a particle when it is created (emitted) or annihilated (absorbed) but as a wave while in transit.

In 1961 Taylor's double-slit experiment was repeated using electron beams as the source by German physicist Claus Jönsson of the University of Tübingen confirming Taylor's prediction of the wave nature of matter.

1913 Niels Bohr a Danish physicist working under Rutherford at Manchester University applied quantum theory to molecular structure proposing a more detailed model of the atom with electrons existing in distinct orbits or shells that had discrete quantised energies, or specific energy levels. Known as the Bohr Model it was later modified to take into account Heisenberg's uncertainty principle which indicated that the electrons occupied distinct shells confusingly called "orbitals" but their position within the orbital was random and could not be known.

Later, he also used Gamow's liquid drop model of the atom to explain nuclear fission.

Bohr proposed that the chemical properties of the element are largely determined by the number of electrons in the outer orbits and introduced the idea that an electron could drop from a higher-energy orbit to a lower one, emitting a photon (light quantum) of discrete energy. This became the basis for quantum mechanics for which he was awarded a Nobel prize in 1922.

Bohr's model of the atom introduced the idea of energy states and quantum numbers and provided the basis for the Pauli Exclusion Principle. It also provided an explanation of the theory behind the