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MAKING THE MODERN WORLD
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scene:James Watt: Life and inventions

James Watt: Life and inventions
James Watt developed the steam engine into a truly viable industrial power source. Here we will look at his work and assess its impact.
Images with this text:
James Watt, engraving by CE Wagstaff after a portrait by Sir William Beechey (1798-1852) of which Watt was particularly proud.
Early lifeThe man
James Watt (1736-1819) was born in Greenock, Scotland, the son of a shipwright. In 1755 he trained for a year as an instrument maker in London. Not only a craftsman, he had an innate love of exploration and experimentation. His friend John Robison once said that 'everything became science in his hands'.
Watt returned to Glasgow in 1757 and opened a shop at the College of Glasgow, where he was styled 'mathematical instrument-maker to the University'. Over the winter of 1763-4, Professor John Anderson sent Watt a model of a Newcomen steam engine that was in need of repair. This was to prove 'not only a turning point in Watt's career but also an important event in the history of civilisation'.
Images with this text:
Portrait of James Watt (1736-1819) by Carl Fredrik von Breda, 1792.
A romantic Victorian interpretation of a young James Watt experimenting with Prof Anderson's model, 1763-4. Mezzotint (published in 1860) engraved by James Scott after an original painting by James Eckford Lauder (1811-1869).
The College of Glasgow, Watt's early workplace. From an engraving in Slezer's Theatrum Scotiae, 1693
Apprenticeship
As a young man, James Watt realised that fulfilling his dream of becoming a mathematical instrument maker would require him to carry out an apprenticeship. Glasgow, where he lived, was not a centre of the mathematical instrument trade so he would have to travel to London in order to train.
Watt made the journey in June 1755. It took him twelve days and upon arrival Watt found it almost impossible to obtain work. The trade guilds regarded him as a 'foreigner', unqualified and too old to become an apprentice. After great difficulty, John Morgan of Finch Lane, Cornhill, was eventually persuaded to give Watt a year's training in return for 20 guineas.
Having been allocated a draughty workbench near the door to Finch's workshop, Watt set out to pack three or four year's training into a single year. He later noted 'we work to nine o'clock every night except Saturdays', and the hard work and poor food affected him badly. He developed a 'racking cough, a gnawing pain in the back and weariness all over the body'.
A year later Watt was able to return to Scotland to set up in business. However his tough training in London left Watt with a legacy of poor health that dogged him for the rest of his life.
Images with this text:
James Watt's home in Delftfield Lane, Glasgow. He moved there having married his cousin Margaret Miller in July 1764. Tragically, Margaret died in 1773 while expecting a child, leaving Watt with two surviving children. Engraving from Samuel Smiles, Lives of Boulton and Watt, 1865.
James Watt's garret workshop, as reconstructed in the Science Museum. Watt maintained the inventive powers developed in his youth right into old age. His workshop contains many items developed in old age, including the sculpturing machines.
Forger?
As a young instrument maker in Glasgow, Watt may have found the going hard. As well as scientific instruments he sold musical instruments like violins, flutes, bagpipes and guitars.
Watt wasn't particularly interested in music but with less demand for scientific instruments than he had anticipated, the sale of musical instruments may have provided an extra source of income.
In the 1760s fashionable young men considered learning the flute as a respectable pastime. From the 1730s Thomas Lot had made high quality flutes for players and aristocratic families across Europe. But while Lot was the Stradivarius of the flute world, many lesser makers sold flutes for only a few shillings each. There is a possibility that young Watt counterfeited copies of the finest flutes available in the seventeenth century.
The evidence is in James Watt's garret workshop. This was presented in its entirety to the Science Museum in 1924 and it remained virtually untouched following Watt's death in 1819.
Curator Michael Wright discovered a number of flute-making tools among the workshop's contents. These include a crude stamp for marking wooden goods with the maker's name. The stamp has four letters: T LOT. To an amateur it presents a 'very passable imitation' of the stamp officially used by Thomas Lot.
What was the stamp doing among Watt's possessions? Being short of money, Watt may have marked his own cheap flutes as being made by Lot, in order to sell them for more profit. A real musician wouldn't mistake a Watt flute for a Lot flute but a gullible amateur might easily do so.
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James Watt's flute-making tools, as preserved in his Garret Workshop at the Science Museum.
The challenge: Better efficiency
The Newcomen engine acquired a reputation for reliability. It was simple and ruggedly designed. However, it used too much fuel and was expensive to build.
Fuel consumption was very high because the Newcomen engine's steam cylinder was heated and cooled at every stroke - heated when steam was let into the cylinder and cooled when it was condensed with cold water. More energy was wasted doing this procedure than was used performing useful work.
Fuel inefficiency restricted the Newcomen engine. Collieries could burn unsaleable waste coal but metal mines in Cornwall had to import coal by sea from South Wales at great cost. The transport costs and tax levied on the coal made widespread use of the Newcomen engine uneconomic for businesses without a ready coal supply.
Although the Newcomen engine was relatively simple, certain elements of its construction, like making the steam cylinder, could be extremely expensive. Initially cylinders were cast in brass and rubbed smooth by hand - an expensive job. An engine erected at Edmonstone Colliery, Midlothian, in 1727 cost £1,007 (excluding its engine house) of which 25% alone was required to pay for the cylinder.
After 1770, the engineer John Smeaton designed a number of improved engines. These were around 50% more efficient than their predecessors. He also developed a cylinder-boring mill that helped reduce the cost of cylinders by 90%.
However by this time new developments were afoot. After 1769 the atmospheric engine was obsolescent. James Watt had invented his separate condenser - the greatest single improvement ever made to the steam engine.
Images with this text:
Elevation of a Newcomen Atmospherical Steam Engine, 1826. Despite its high fuel consumption, its reliability often kept the Newcomen engine in use long after other alternatives became available.
John Smeaton, English mechanical and civil engineer (1724-92).
John Smeaton's improved atmospheric engine at Chacewater Mine, erected in 1775. The laminated beam seen on this engine was one of a number of changes Smeaton made to the basic Newcomen engine design.
Watt's breakthroughEarly experiments
Having repaired Anderson's model engine, Watt found it would only make a few strokes before stopping, leaving the boiler exhausted of steam. Measuring the volume of steam used in the cylinder in comparison to the water from which it was formed, he found that at each piston stroke the model used enough steam to fill the cylinder several times over.
Watt discovered that this high steam consumption was the result of having to heat and cool the cylinder at each stroke. The dilemma was this: for maximum fuel 'economy' the cylinder had to be kept hot all the time but for maximum 'power' it had to be cooled down once every cycle - so that the energy in the form of heat was converted into mechanical energy.
Watt's solution was to condense the steam in a separate condenser, not the cylinder. This allowed the cylinder to be kept at a constant temperature while also allowing the steam to be cooled and condensed back into water.
Images with this text:
Anderson's model engine, 1765. It was while repairing this engine that Watt began to think about how his separate condenser would work.
James Watt's second separate condenser model, 1765. Made from tinplate and lead castings, it was acquired from James Watt & Co in 1876.
The cover of a copy of Watt's 1769 patent, 1855. The patent gave Watt much trouble prior to its expiry in 1800.
Breakthrough! : Watt's thoughts
The breakthrough came in May 1765, as recalled by Watt:
'It was in the Green of Glasgow. I had gone to take a walk on a fine Sabbath afternoon. I had entered the Green by the gate at the foot of Charlotte street - had passed the old washing-house.''I was thinking upon the engine at the time and had gone as far as the Herd's house when the idea came into my mind, that as steam was an elastic body it would rush into a vacuum, and if a communication was made between the cylinder and an exhausted vessel, it would rush into it, and might there be condensed without cooling the cylinder.' 'I then saw that I must get quit of the condensed steam and injection water, if I used a jet as in Newcomen's engine. Two ways of doing this occurred to me.''First the water might be run off by a descending pipe and any air might be extracted by a small pump; the second was to make the pump large enough to extract both water and air I had not walked further than the Golf-house when the whole thing was arranged in my mind.'
The chance to implement this pioneering plan did not come immediately. It took ten years of intermittent work to develop a satisfactory engine. But in 1769 Watt finally obtained his patent for 'A new Method of Lessening the Consumption of Steam and Fuel in Fire Engines'.
Images with this text:
Portrait of James Watt.
A Scottish pastoral scene, 1849.
James Watt's home in Delftfield Lane, Glasgow.
A cutaway diagram of Watt's second separate condenser model, with steam cylinder, condenser and air pump.
James Watt's experimental separate condenser, 1765. This tinplate model condenser with rudimentary air pump was found in Watt's Workshop, and corresponds to his description of his first model.
Detail showing jet of cold water being sprayed into the cylinder of a Newcomen Atmospherical Steam Engine, 1826.
Drawing of Watt's 'Lap' beam engine including his separate condenser the greatest single improvement ever made to the steam engine.
The cover of a copy of Watt's 1769 patent, 1855
Supporting castPartners: Black, Roebuck and Boulton
Development of Watt's separate condenser relied on many supporting characters. Joseph Black, known for his research on latent heat at the University of Glasgow, provided Watt with a generous loan. Later John Roebuck, an industrial chemist with considerable mining interests, assumed responsibility for Watt's debt to Black in return for a share in Watt's 1769 patent. Watt built an experimental engine at Roebuck's house but work slowed as he took up practise as a surveyor to support his family. Roebuck was declared bankrupt in 1773 but before that he had the foresight to introduce Watt to Matthew Boulton.
Boulton came from Birmingham and had built for himself a reputation as a manufacturer. His Soho Manufactory employed around 600 people and made all types of 'steel gilt, fancy buttons, steel watch chains, plated wares, [and] ornamental works in ormoulu and tortoiseshell'. Boulton was impressed by Watt's invention and appreciated its great potential. In a letter to Watt he wrote
'I was excited by two motives to offer you my assistance which were love of you and love of a money-getting ingenious project.'
Boulton agreed to take over Roebuck's share in the separate condenser patent, and had Watt's experimental engine shipped to his Soho Manufactory. There, at last, Watt could devote all his time to perfecting its operation. With only eight years of the 1769 patent left to run, Parliament was petitioned for a 25-year extension. Although vigorously opposed, this received assent on May 22, 1775. Shortly afterwards, Boulton & Watt entered into formal partnership - one of the most important of the entire industrial revolution.
Images with this text:
Matthew Boulton (1728-1809), leading Birmingham industrialist and business partner of James Watt. Engraving by William Sharp after an original oil painting of 1801 by William Beechey.
Engraving of the Soho Manufactory near Birmingham, 1830.
The engine erected by James Watt at Kinneil, Scotland, 1765, and later transported to Birmingham. Its development was slowed by Watt's work as a canal surveyor. His first successful full-size engines were erected at Staffordshire's Bloomfield Colliery and Shropshire's Broseley Ironworks in 1775.
The case of the missing deeds
James Watt and Matthew Boulton entered into a formal business relationship in 1775. Although this was one of the great partnerships of the industrial revolution in England, it would appear that nothing was ever formally committed to paper.
In June 1776 Watt travelled back to Scotland with the intention of finding a second wife, his first having tragically died. Having found a new future spouse, Watt faced a dilemma. His prospective father-in-law, being a canny man, requested to see proof of Watt's partnership with Boulton. But no contract or agreement existed.
Watt passed the matter over to Boulton, who determined to prevaricate his way out of trouble. On July 3rd, he wrote to Watt's future father-in-law:
'I would without hesitation have sent you the assignment and the article of partnership had it been in my power, but Mr Dadley, the lawyer, is suddenly called to London, and it cannot be had before his return.'
Historians continue to debate the existence or otherwise of a formal partnership agreement between Boulton and Watt.
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Contract between Boulton & Watt and the British Cast Plate Glass Co for the supply of a 14 Horse Power steam engine, 1788. Given Boulton & Watt's meticulously detailed engine contracts, it is surprising that they may never have completed a formal partnership agreement, although an incomplete draft exists.
The Lunar Society
Boulton and Watt were based in Birmingham, England, a booming industrial city at the forefront of technological development.
A centre of so many new developments in industry, Birmingham was home to a prominent group of local scientists, experimenters and industrialists. As they held their regular meetings on nights with a full moon (to safely illuminate their journeys home) they became known as the Lunar Society.
The irreverently-named 'Lunatics' included among others, Josiah Wedgwood (who developed his rationally organised manufactory at Etruria in 1769), Erasmus Darwin (physician and grandfather of Charles Darwin) and Joseph Priestley, discoverer of oxygen.
In such an innovative environment James Watt worked on many of the developments that would make the steam engine a viable entity.
Images with this text:
Erasmus Darwin, English physician, 1797. Mezzotint by J R Smith after a painting by Joseph Wright c.1793.
oseph Priestley, English-American theologian and chemist. Engraving by Ambroise Tardieu after his original drawing.
Soho House, Matthew Boulton's residence, where the Lunar Society frequently met.
Portable letter-copying press, c.1800, designed by James Watt Jnr and manufactured by James Watt & Co. The copying process used was patented by James Watt Snr in 1780, and marketed in partnership with James Keir, fellow 'Lunatic'.
ImpactBoulton and Watt
The effect of the separate condenser was profound and engines using it reduced coal consumption by two thirds or more. At the Great Consols Mine in Cornwall, seven Newcomen engines consumed 19,086 tons of coal in 1778-79. Five Boulton & Watt engines replaced them by 1783, burning only 6,090 tons of coal that year.
Watt's engines were an immediate success. In only a few years they completely replaced the Newcomen engine in Cornwall. Boulton & Watt had to quickly decide how to exploit interest in their engine. They charged a premium to all users equal to one third of the saving in fuel costs compared to an atmospheric engine. Later, in 1786, they replaced the premium with a charge of £5 per horsepower per year.
Until 1795, Watt and Boulton worked as consulting engineers. They provided drawings, an engine erector and some specialised components such as valves and valve gear but left most other aspects of construction to their customers. Engine manufacture only occupied a small part of Boulton's Soho Manufactory. In the 1790s, with the end of their patent protection fast approaching, Boulton and Watt took steps to consolidate their position and 'systematise' engine construction. The result was the Soho Foundry. As Boulton & Watt's partnership matured, so did the design of their engines.
Images with this text:
James Watt's single-acting pumping engine, 1788. Coal consumption of these engines could be as little as 7.5lb per hp/hour, compared to 30-45lb per hp/hour for the original Newcomen engine, and 17-18lb per hp/hour for Smeaton's improved version.
Watt's engine counter. Calculating the premium payable on Watt engines involved measuring the number of working strokes made. This was done using mechanical counters like this, the first being acquired in 1779. The mechanism is enclosed in a box, to which only agents of Boulton & Watt could gain access.
Elevation of the cylinder, condenser and governor of a Watt 56 hp steam engine.
A wave of inventions
Realising the huge potential market for reliable and efficient steam engines, Watt's work on rotary motion from 1782 was accompanied by a range of other innovations.
The first was to make engines 'double-acting'. This entailed applying steam to both faces of the piston alternately rather than only to the top as before. This doubled the power that could be developed from the same cylinder volume.
James Watt also experimented with the expansive use of steam. The steam supply to the cylinder was cut off only partway through the stroke, allowing the steam to exert force on the piston by expanding, albeit with diminishing force. This allowed considerable fuel savings by reducing the amount of steam used. In 1784 Watt solved the problem by connecting a piston rod moving perpendicularly to the end of a beam that formed a segment of an arc as it went up and down. With the advent of double-acting engines his 'parallel motion' was vital and Watt was particularly proud of its graceful motion.
In 1787 Watt introduced the centrifugal governor, designed to regulate the speed of an engine while the load placed upon it fluctuated. Watt never claimed this invention as his own as it was already used in flour mills to regulate the speed and separation of millstones.
In a few short years Watt had introduced the major innovations that were to remain central to steam engine design for a long time. However, technical innovation was increasingly matched by legal disputes as others sought to undermine Watt's position.
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Watt's non-rotative beam engine, 1777. This was the second engine built at Matthew Boulton's Soho Manufactory. Used to experiment with expansive working, it proved so hard to control that it obtained a nickname - Beelzebub. Later it recirculated water over a wheel, which it did successfully until 1840, earning a kinder name - Old Bess.
The centrifugal governor of James Watt's 'Lap' engine, 1788.
Centrifugal governor from a windmill in East Anglia, 1780-1820.
Rise of the rotative engine
Before 1782, Boulton & Watt only built pumping engines. Watt would gladly have continued this business but Boulton saw a new field - industrial power for factories. He sensed that people were going 'steam mill mad':
'I think that mills present a field that is boundless and that will be more permanent than these transient mines, and more satisfactory than these inveterate, ungenerous and envious miners and mine lords.'
Boulton foresaw the demand for an engine that could produce a rotary motion which could be used to drive factory machinery. Watt built his first engine producing rotary motion to drive factory machinery at Soho in 1782 and soon after supplied his first outside Soho to John Wilkinson of Bersham.
In 1789 James Pickard of Birmingham had patented the crank, the easiest means of converting the vertical motion of the piston into the rotary motion of a flywheel in 1780. Watt was forced to develop a range of alternatives instead, including his 'sun-and-planet' gearing system. Watt made sun-and-planet engines until 1802 although he also built crank engines from 1794, when Pickard's patent expired.
The rotative engine comprised over 60% of the 496 engines built by Boulton & Watt before 1800.
Images with this text:
James Watt's 'Lap' beam engine, 1788. The oldest surviving engine made by Watt to survive complete and essentially unaltered, It drove metal polishing (or 'lapping') machinery in Matthew Boulton's Soho Manufactory for 70 years.
Model of sun-and-planet gear, preserved by James Watt & Company.
Alternatives to Boulton & Watt
Until 1800, Boulton and Watt only constructed about 25% of the steam engines in use in Britain. What other power sources was industry using?
One alternative to a Watt rotative engine was the recirculating engine - a Newcomen or Savery engine recirculating water over a waterwheel between reservoirs. Such engines were simple and reliable and could be used to supplement a waterwheel in case a drought curtailed water supplies.
The waterwheel remained widely used in industry and benefited from a range of improvements. Iron replaced wood in wheel construction. Thomas Hewes developed the suspension wheel (where mill machinery was driven via a pinion drive on the wheel rim as opposed to the main axle of the wheel itself). Waterwheels became lighter, stronger and larger.
The evidence suggests that older power sources remained viable choices for many after the advent of Watt's engine.
Images with this text:
Model of Old Bess recirculating engine, 1777. After a brief career experimenting with expansive working, this engine was used by James Watt to recirculate water over a waterwheel to power Matthew Boulton's Soho Manufactory.
Ten Horse Power atmospheric engine, c.1826. Newcomen engines continued to be built as an alternative to the Watt engine into the nineteenth century.
Model, scale 1:12, of breastshot suspension water wheel, c.1888. The wheel is built entirely of iron with ventilated buckets to ensure rapid filling and emptying, tension spokes to save weight, and a ring gear bolted round its circumference allowing power to be taken off by a pinion gear.
The patent battles
While Watt's engine was the best available, he still faced major challenges. Cornish miners objected to paying a premium for using his engine and other engineers wanted a share of the lucrative engine market.
In 1781 Jonathan Hornblower patented an engine that infringed Watt's 1769 patent by using a separate condenser. Hornblower failed to obtain an extension on his patent and Boulton & Watt saw off a succession of pirates. However, the real battle was yet to come.
Jabez Hornblower, brother of Jonathan, was a man of 'bad-tempered and ungracious disposition'. In 1795 he began building engines that used the separate condenser and Boulton & Watt served an injunction against him. On December 16, 1796, a court found against Hornblower. He appealed on the grounds that Watt's patent was invalid.
The judgment was withheld until January 1799 while a similar case was tried against Edward Bull, whose engine design also infringed Watt's patent. Eventually the court affirmed its judgment supporting Watt, who immediately began collecting huge premium arrears in Cornwall.
For all their success at suppressing wider use of the separate condenser, Boulton & Watt built only a quarter of the engines used in Britain in 1800 - approximately 500 out of 2000. But they possessed a qualitative edge that other makers could not match.
Images with this text:
Model, scale 1:12, of breastshot suspension water wheel, c.1888. The wheel is built entirely of iron with ventilated buckets to ensure rapid filling and emptying, tension spokes to save weight, and a ring gear bolted round its circumference allowing power to be taken off by a pinion gear.
Heslop's engine of 1795, preserved in the Science Museum. Patented by Adam Heslop, fourteen engines of this type were installed around Cumbria before James Watt successfully claimed they infringed his separate condenser patent.
Jonathan Hornblower, 1753-1815.
Revolutionary or reactionary?
Technically, James Watt's steam engine was the best available up until 1800. But it has been claimed Watt's vigorous defence of his separate condenser patent blocked wider access to the greatest single improvement in engine efficiency ever and stifled adequate investigation into alternatives.
Boulton & Watt refused to license other engine builders to use the separate condenser. Industry faced the choice of paying Watt the premium or using a less efficient atmospheric engine. Whatever their choice, the price in fuel or premium payments was heavy.
Beyond 1800 Watt's company held an unassailable position despite the ending of his patents. In 1827 John Farey wrote:
'Men of superior intellect, who might have been induced to investigate the subject, have been led to suppose that nothing further remains to be perfected'
With hindsight this was manifestly not the case. The road to the larger and more efficient engines demanded by industry lay in the adoption of higher steam pressures.
But for the time being at least 'the authority he [Watt] wielded was such as to clog engineering enterprise for more than a generation.'
Image with this text:
Detail of Boulton & Watt rotative steam engine, drawn by John Farey, 1812, from Rees' Cyclopedia, 1819.

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