Editing James Watt (section)

== Scientific studies and inventions ==

===Watt and the kettle===
There is a popular story that Watt was inspired to invent the steam engine by seeing a kettle boiling, the steam forcing the lid to rise and thus showing Watt the power of steam. This story is told in many forms; in some Watt is a young lad, in others he is older, sometimes it's his mother's kettle, sometimes his aunt's, suggesting that it may be apocryphal. In any event, Watt did not ''invent'' the steam engine, but significantly ''improved the efficiency'' of the existing [[Newcomen atmospheric engine|Newcomen engine]] by adding a [[Watt steam engine#Separate condenser|separate condenser]], consistent with the now-familiar principles of [[thermal efficiency]]. The story was possibly created by Watt's son, [[James Watt junior|James Watt, Jr.]], who was determined to preserve and embellish his father's legacy.<ref>{{cite journal |title=True Myths: James Watt's Kettle, His Condenser, and His Chemistry |last=Miller |first=D. P. |journal=[[History of Science (journal)|History of Science]] |year=2004 |volume=42 |issue=3 |pages=333–360 [p. 334] |doi=10.1177/007327530404200304 |bibcode=2004HisSc..42..333M |s2cid=161722497 }}</ref> In this light, it can be seen as akin to the story of [[Isaac Newton#Apple incident|Isaac Newton and the falling apple]] and his discovery of [[gravity]].

Although likely a myth, the story of Watt and the kettle has a basis in fact. In trying to understand the [[thermodynamics]] of heat and steam, James Watt carried out many laboratory experiments and his diaries record that in conducting these, he used a kettle as a [[boiler]] to generate steam.<ref>{{cite book |title=Science and Technology in the Industrial Revolution |first1=A. E. |last1=Musson |first2=Eric |last2=Robinson |publisher=Manchester University Press |year=1969 |page=80 }}</ref>

===Early experiments with steam===
[[File:James Eckford Lauder - James Watt and the Steam Engine- the Dawn of the Nineteenth Century - Google Art Project.jpg|thumb|left|[[James Eckford Lauder]]: ''James Watt and the Steam Engine: the Dawn of the Nineteenth Century'', 1855]]
[[File:Watts First Condenser.jpg|thumb|[[Watt's separate condenser|Original condenser]] by Watt ([[Science Museum (London)|Science Museum]])]]

In 1759 Watt's friend [[John Robison (physicist)|John Robison]] called his attention to the use of steam as a source of [[Power (physics)|motive power]].<ref name="Muirhead1858">{{cite book|last=Muirhead|first=James Patrick|title=The life of James Watt: with selections from his correspondence|url=https://archive.org/details/lifejameswattwi03muirgoog|access-date=17 August 2011|year=1858|publisher=J. Murray|pages=[https://archive.org/details/lifejameswattwi03muirgoog/page/n99 74]–83}}</ref> The design of the Newcomen engine, in use for almost 50 years for pumping water from mines, had hardly changed from its first implementation. Watt began to experiment with steam, though he had never seen an operating steam engine. He tried constructing a model; it failed to work satisfactorily, but he continued his experiments and began to read everything he could about the subject. He came to realise the importance of [[latent heat]]—the [[thermal energy]] released or absorbed during a constant-temperature process—in understanding the engine, which, unknown to Watt, his friend [[Joseph Black]] had previously discovered years before. Understanding of the steam engine was in a very primitive state, for the science of [[thermodynamics]] would not be formalised for nearly another 100 years.

In 1763, Watt was asked to repair a model Newcomen engine belonging to the university.<ref name="Muirhead1858"/> Even after repair, the engine barely worked. After much experimentation, Watt demonstrated that about three-quarters of the thermal energy of the steam was being consumed in heating the [[Cylinder (engine)|engine cylinder]] on every cycle.<ref name="FrazerPa1859">{{cite book|last=Frazer|first=Persifor|title=Journal of the Franklin Institute|url=https://books.google.com/books?id=o3oqAQAAIAAJ&pg=PA296|access-date=17 August 2011|year=1859|pages=296–297}}</ref> This energy was wasted because, later in the cycle, cold water was injected into the cylinder to [[condense]] the steam to reduce its pressure. Thus, by repeatedly heating and cooling the cylinder, the engine wasted most of its thermal energy rather than converting it into [[mechanical energy]].

Watt's critical insight, arrived at in May 1765 as he crossed [[Glasgow Green]] park,<ref>Dickinson, p. 36.</ref> was to cause the steam to condense in a separate chamber apart from the [[piston]], and to maintain the temperature of the cylinder at the same temperature as the injected steam by surrounding it with a "steam jacket".<ref name="FrazerPa1859"/> Thus, very little energy was absorbed by the cylinder on each cycle, making more available to perform useful work. Watt had a working model later that same year.

[[File:James Watt Cottage ruin, Kinneil House, Bo'ness.JPG|thumb|left|The ruin of Watt's cottage workshop at [[Kinneil House]]<ref>{{cite web|title=OS 25-inch 1892–1949|url=http://maps.nls.uk/geo/explore/#zoom=17&lat=56.0081&lon=-3.6337&layers=168&b=1|website=National Library of Scotland|publisher=Ordnance Survey|access-date=26 October 2017}}</ref>]]
[[File:James Watt steam engine relic at the Carron Works.JPG|thumb|[[Cylinder (engine)|Cylinder]] fragment of Watt's first operational engine at the [[Carron Works]], Falkirk]]

Despite a potentially workable design, there were still substantial difficulties in constructing a full-scale engine. This required more [[Financial capital|capital]], some of which came from Black. More substantial backing came from [[John Roebuck]], the founder of the celebrated [[Carron Iron Works]] near [[Falkirk]], with whom he now formed a partnership. Roebuck lived at [[Kinneil House]] in [[Bo'ness]], during which time Watt worked at perfecting his steam engine in a cottage adjacent to the house.<ref>{{cite book|last1=Salmon|first1=Thomas James|title=Borrowstounness and district, being historical sketches of Kinneil, Carriden, and Bo'ness, c. 1550–1850|date=1913|publisher=William Hodge and Co.|location=Edinburgh|pages=372–376|url=https://archive.org/stream/borrowstounnessd00salmrich#page/270/mode/2up|access-date=9 December 2017}}</ref> The shell of the cottage, and a very large part of one of his projects, still exist to the rear.<ref>"James Watt's Cottage", CANMORE. Royal Commission on the Ancient and Historical Monuments of Scotland. Retrieved 13 May 2010.</ref>

The principal difficulty was in machining the piston and cylinder. [[Iron (material)|Iron]] workers of the day were more like [[blacksmith]]s than modern [[machinist]]s, and were unable to produce the components with sufficient precision. Much capital was spent in pursuing a [[patent]] on Watt's invention. Strapped for resources, Watt was forced to take up employment—first as a [[surveyor (surveying)|surveyor]], then as a [[civil engineer]]—for 8 years.<ref>Hills, vol. I, pp. 180–293.</ref>

{{anchor|James Watt's Fire Engines Patent Act 1775}}
Roebuck went [[Bankruptcy in the United Kingdom|bankrupt]], and [[Matthew Boulton]], who owned the [[Soho Manufactory]] works near [[Birmingham]], acquired his patent rights. An [[Patent extensions|extension]] of the patent to 1800 was successfully obtained in 1775.{{efn|James Watt's Fire Engines Patent Act 1775 ([[15 Geo. 3]]. c. 61). At the time, an [[Act of Parliament]] was required to extend a patent.}}

Through Boulton, Watt finally had access to some of the best iron workers in the world. The difficulty of the manufacture of a large cylinder with a tightly fitting piston was solved by [[John Wilkinson (industrialist)|John Wilkinson]], who had developed precision boring techniques for [[cannon]] making at [[Bersham Ironworks|Bersham]], near [[Wrexham]], [[North Wales]]. Watt and Boulton formed a hugely successful partnership, [[Boulton and Watt]], which lasted for the next 25 years.

===First engines===
[[File:SteamEngine Boulton&Watt 1784.png|thumb|left|Engraving of a 1784 [[Watt steam engine|steam engine]] designed by [[Boulton and Watt]]]]
{{Main|Watt steam engine|Watt's linkage|Watt's curve}}
In 1776, the first engines were installed and working in commercial enterprises. These first engines were used to power pumps and produced only [[reciprocating motion]] to move the pump rods at the bottom of the shaft. The design was commercially successful, and for the next five years, Watt was very busy installing more engines, mostly in [[Cornwall]], for pumping water out of mines.

These early engines were not manufactured by Boulton and Watt, but were made by others according to drawings made by Watt, who served in the role of [[consulting engineer]]. The erection of the engine and its [[shakedown (testing)|shakedown]] was supervised by Watt, at first, and then by men in the firm's employ, with the actual work being accomplished by the purchaser of the engine. Supervising erectors included at various times [[William Murdoch]], [[John Rennie the Elder|John Rennie]], [[William Playfair]], [[John Southern (engineer)|John Southern]], [[Logan Henderson (engineer)|Logan Henderson]], [[James Lawson (engineer)|James Lawson]], [[William Brunton]], [[Isaac Perrins]], and others.

These were large machines. The first, for example, had a cylinder with a diameter of 50&nbsp;inches and an overall height of about 24 feet, and required the construction of a dedicated building to house it. Boulton and Watt charged an annual payment, equal to one-third of the value of the coal saved in comparison to a Newcomen engine performing the same work.

The field of application for the invention was greatly widened when Boulton urged Watt to convert the reciprocating motion of the piston to produce [[Rotational energy|rotational power]] for grinding, weaving and milling. Although a [[crank (mechanism)|crank]] seemed the obvious solution to the conversion, Watt and Boulton were stymied by a patent for this, whose holder, [[James Pickard]] and his associates proposed to cross-license the external condenser. Watt adamantly opposed this and they circumvented the patent by their [[sun and planet gear]] in 1781.

Over the next six years, he made other improvements and modifications to the steam engine. A double-acting engine, in which the steam acted alternately on both sides of the piston, was one. He described methods for working the steam "expansively" (i.e., using steam at pressures well above atmospheric). A [[compound engine]], which connected two or more engines, was described. Two more patents were granted for these in 1781 and 1782. Numerous other improvements that made for easier manufacture and installation were continually implemented. One of these included the use of the steam [[indicator diagram|indicator]] which produced an informative plot of the pressure in the cylinder against its volume, which he kept as a [[trade secret]]. Another important invention, one which Watt was most proud of, was the [[parallel motion|parallel motion linkage]], which was essential in double-acting engines as it produced the straight line motion required for the cylinder rod and pump, from the connected rocking beam, whose end moves in a [[circular arc]]. This was patented in 1784. A [[throttle]] valve to control the power of the engine, and a [[centrifugal governor]], patented in 1788,<ref>{{cite book|last=Brown|first=Richard|title=Society and Economy in Modern Britain 1700–1850|url=https://archive.org/details/societyeconomymo00brow|url-access=limited|publisher=Routledge|location=London|year=1991|page=[https://archive.org/details/societyeconomymo00brow/page/n74 60]|isbn=978-0-203-40252-8}}</ref> to keep it from "running away" were very important. These improvements taken together produced an engine which was up to five times as [[Fuel efficiency|fuel efficient]] as the Newcomen engine.

Because of the danger of exploding boilers, which were in a very primitive stage of development, and the ongoing issues with leaks, Watt restricted his use of high pressure steam&nbsp;– all of his engines used steam at near atmospheric pressure.

===Patent trials===
[[File:20070616 Dampfmaschine.jpg|thumb|A steam engine built to James Watt's patent in 1848 at [[Freiberg, Saxony|Freiberg]] in Germany]]
[[Edward Bull]] started constructing engines for Boulton and Watt in Cornwall in 1781. By 1792, he had started making engines of his own design, but which contained a separate condenser, and so infringed Watt's patents. Two brothers, [[Jabez Carter Hornblower]] and [[Jonathan Hornblower]] Jnr also started to build engines about the same time. Others began to modify Newcomen engines by adding a condenser, and the mine owners in Cornwall became convinced that Watt's patent could not be enforced. They started to withhold payments to Boulton and Watt, which by 1795 had fallen on hard times. Of the total £21,000 (equivalent to £{{formatnum:{{Inflation|UK|21000|1795|{{Inflation-year|UK}}|r=-4}}}} as of {{Inflation-year|UK}}) owed, only £2,500 had been received. Watt was forced to go to court to enforce his claims.<ref>Hills, vol. 3, ch. 5 and 6.</ref>

He first sued Bull in 1793. The jury found for Watt, but the question of whether or not the original specification of the patent was valid was left to another trial. In the meantime, injunctions were issued against the [[Patent infringement|infringers]], forcing their payments of the [[Royalty payment|royalties]] to be placed in [[escrow]]. The trial on determining the validity of the specifications which was held in the following year was inconclusive, but the injunctions remained in force and the infringers, except for Jonathan Hornblower, all began to settle their cases. Hornblower was soon brought to trial in 1799, and the verdict of the four was decisively in favour of Watt. Their friend John Wilkinson, who had solved the problem of boring an accurate cylinder, was a particularly grievous case. He had erected about 20 engines without Boulton's and Watts' knowledge. They finally agreed to settle the infringement in 1796.<ref>Roll, p. 158.</ref> Boulton and Watt never collected all that was owed them, but the disputes were all settled directly between the parties or through [[arbitration]]. These trials were extremely costly in both money and time, but ultimately were successful for the firm.

===Copying machine===
[[File:Portable Copying Machine by James Watt & Co.jpg|thumb|Portable Copying Machine by James Watt & Co. Circa 1795]]
Before 1780, there was no good method for making copies of letters or drawings. The only method sometimes used was a mechanical one using multiple linked pens. Watt at first experimented with improving this method, but soon gave up on this approach because it was so cumbersome. He instead decided to try to physically transfer ink from the front of the original to the back of another sheet, moistened with a solvent, and pressed to the original. The second sheet had to be thin, so that the ink could be seen through it when the copy was held up to the light, thus reproducing the original exactly.<ref>Hills, Vol. 2, pp. 190–211.</ref><ref>W. B. Proudfoot, ''Origin of Stencil Duplicating'', p. 21, as quoted at Quaritch.com, 12 October 13.</ref>

Watt started to develop the process in 1779, and made many experiments to formulate the ink, select the thin paper, to devise a method for wetting the special thin paper, and to make a press suitable for applying the correct pressure to effect the transfer. All of these required much experimentation, but he soon had enough success to patent the process a year later. Watt formed another partnership with Boulton (who provided financing) and [[James Keir]] (to manage the business) in a firm called James Watt and Co. The perfection of the invention required much more development work before it could be routinely used by others, but this was carried out over the next few years. Boulton and Watt gave up their shares to their sons in 1794.<ref>Hills, vol. 3, p. 116.</ref> It became a commercial success and was widely used in offices even into the 20th century.

===Chemical experiments===
From an early age, Watt was very interested in chemistry. In late 1786, while in Paris, he witnessed an experiment by [[Claude Louis Berthollet]] in which he reacted [[hydrochloric acid]] with [[manganese dioxide]] to produce [[chlorine]]. He had already found that an [[aqueous solution]] of chlorine could [[bleach]] textiles, and had published his findings, which aroused great interest among many potential rivals. When Watt returned to Britain, he began experiments along these lines with hopes of finding a commercially viable process. He discovered that a mixture of salt, manganese dioxide and [[sulphuric acid]] could produce chlorine, which Watt believed might be a cheaper method. He passed the chlorine into a weak solution of [[alkali]], and obtained a [[Turbidity|turbid]] solution that appeared to have good bleaching properties. He soon communicated these results to James McGrigor, his father-in-law, who was a bleacher in Glasgow. Otherwise, he tried to keep his method a secret.<ref>Hills, vol. 3, ch. 4.</ref>

With McGrigor and his wife Annie, he started to scale up the process, and in March 1788, McGrigor was able to bleach {{Convert|1500|yd|ft|abbr=off}} of cloth to his satisfaction. About this time, Berthollet discovered the salt and sulphuric acid process, and published it, so it became public knowledge. Many others began to experiment with improving the process, which still had many shortcomings, not the least of which was the problem of transporting the liquid product. Watt's rivals soon overtook him in developing the process, and he dropped out of the race. It was not until 1799, when [[Charles Tennant]] patented a process for producing solid bleaching powder ([[calcium hypochlorite]]) that it became a commercial success.

By 1794, Watt had been chosen by [[Thomas Beddoes]] to manufacture apparatuses to produce, clean and store gases for use in the new [[Pneumatic Institution]] at [[Hotwells]] in [[Bristol]]. Watt continued to experiment with various gases, but by 1797, the medical uses for the "[[factitious airs]]" (artificial gases) had come to a dead end.<ref>Hills, vol. 3, pp. 152–58.</ref>[[File:Watt apparatus 3.JPG|thumb|Scientific apparatus designed by [[Boulton and Watt]] in preparation of the [[Pneumatic Institution]] in Bristol]]

===Personality===
Watt combined theoretical knowledge of science with the ability to apply it practically. The chemist [[Humphry Davy]] said of him, "Those who consider James Watt only as a great practical mechanic form a very erroneous idea of his character; he was equally distinguished as a [[natural philosopher]] and a chemist, and his inventions demonstrate his profound knowledge of those sciences, and that peculiar characteristic of genius, the union of them for practical application".<ref>{{cite book|last=Carnegie|first=Andrew|title=James Watt|url=http://www.history.rochester.edu/steam/carnegie/ch10.html|year=1905|publisher=Doubleday, Page and Company|chapter=10|url-status=dead|archive-url=http://arquivo.pt/wayback/20090708035219/http://www.history.rochester.edu/steam/carnegie/ch10.html|archive-date=8 July 2009}}</ref>

He was greatly respected by other prominent men of the [[Industrial Revolution]].<ref>Carnegie, chap. XI: ''Watt, the Man''.</ref> He was an important member of the [[Lunar Society of Birmingham]], and was a much sought-after conversationalist and companion, always interested in expanding his horizons.<ref>Hills, vol I, pp. 42–43.</ref> His personal relationships with his friends and business partners were always congenial and long-lasting.

According to Lord Liverpool (Prime Minister of the UK),<ref>{{cite book|last1=Laidler|first1=Keith J.|title=To Light such a Candle|date=1993|publisher=Oxford University Press|page=18}}
</ref>
<blockquote>A more excllent and amikable man in all the relations of life I believe never existed.</blockquote>

Watt was a prolific correspondent. During his years in [[Cornwall]], he wrote long letters to Boulton several times per week. He was averse to publishing his results in, for example, the ''[[Philosophical Transactions of the Royal Society]]'' however, and instead preferred to communicate his ideas in [[patents]].<ref>{{Cite book| last=Smiles| first=Samuel| title=Lives of Boulton and Watt: A History of the Invention and Introduction of the Steam Engine| url=https://archive.org/stream/livesofengineers04smiluoft#page/286/mode/2up | publisher=John Murray| place=London| year=1865 | page=286}}</ref> He was an excellent [[Drafter|draughtsman]].

[[File:James Watt's letters from the Science Museum Library & Archives in Wroughton.jpg|thumb|James Watt's letters from the [[Science Museum at Wroughton|Science Museum Library & Archives in Wroughton]], near Swindon]]

He was a rather poor businessman, and especially hated bargaining and negotiating terms with those who sought to use the steam engine. In a letter to [[William Small]] in 1772, Watt confessed that "he would rather face a loaded cannon than settle an account or make a bargain."<ref>Roll, p. 20</ref> Until he retired, he was always very concerned about his financial affairs, and was something of a worrier. His health was often poor and he suffered frequent nervous headaches and depression. When he retired in 1800, he became a rich enough man to pass the business on to his sons.

===Soho Foundry===
At first, the partnership made the drawings and specifications for the engines, and supervised the work to erect them on the customers' property. They produced almost none of the parts themselves. Watt did most of his work at his home in Harper's Hill in Birmingham, while Boulton worked at the [[Soho Manufactory]]. Gradually, the partners began to actually manufacture more and more of the parts, and by 1795, they purchased a property about a mile away from the Soho Manufactory, on the banks of the [[BCN Main Line|Birmingham Canal]], to establish a new foundry for the manufacture of the engines. The [[Soho Foundry]] formally opened in 1796 at a time when Watt's sons, Gregory and James Jr. were heavily involved in the management of the enterprise. In 1800, the year of Watt's retirement, the firm made a total of 41 engines.<ref>Roll, p. 280.</ref>

===Later years===
[[File:Heathfield Hall, Handsworth by Allen Edward Everitt.jpg|thumb|An 1835 painting of "[[Heathfield Hall|Heathfield]]", Watt's house in [[Handsworth, West Midlands|Handsworth]], by [[Allen Edward Everitt]] ]]
[[File:James Watt's Workshop.jpg|thumb|upright|James Watt's workshop]]
Watt retired in 1800, the same year that his fundamental patent and partnership with Boulton expired. The famous partnership was transferred to the men's sons, [[Matthew Robinson Boulton]] and [[James Watt junior|James Watt, Junior]]. The long-time firm engineer [[William Murdoch]] was soon made a partner and the firm prospered.

Watt continued to invent other things before and during his semi-retirement. Within his home in [[Handsworth, West Midlands|Handsworth]], Staffordshire, Watt made use of a [[garret]] room as a workshop, and it was here that he worked on many of his inventions.<ref>Dickinson, ch. VII.</ref> Among other things, he invented and constructed machines for copying sculptures and medallions which worked very well, but which he never patented.<ref>Hills, vol. 3, pp. 234–37.</ref> One of the first sculptures he produced with the machine was a small [[Bust (sculpture)|head]] of his old professor friend [[Adam Smith]]. He maintained his interest in civil engineering and was a consultant on several significant projects. He proposed, for example, a method for constructing a flexible pipe to be used for pumping water under the [[River Clyde]] at Glasgow.<ref>Hills, vol 3, pp. 230–31</ref>

He and his second wife travelled to France and Germany, and he purchased an estate in mid-Wales at Doldowlod House, one mile south of [[Llanwrthwl]], which he much improved.

In 1816, he took a trip on the [[Paddle steamer|paddle-steamer]] ''[[PS Comet|Comet]]'', a product of his inventions, to revisit his home town of Greenock.<ref>Robert Chambers' Book of Days.</ref>

He died on 25 August 1819 at his home "[[Heathfield Hall]]" near Handsworth in Staffordshire (now part of Birmingham) at the age of 83.<ref>{{cite news |url=https://www.britishnewspaperarchive.co.uk/viewer/bl/0002762/18190829/024/0008 |title=Deaths. |newspaper=Wooler's British Gazette |date=29 August 1819 |page=8 |via=British Newspaper Archive |access-date=18 September 2024}}</ref><ref>{{cite news |url=https://www.britishnewspaperarchive.co.uk/viewer/bl/0002644/18190830/019/0008 |title=Died. |newspaper=The National Register |date=30 August 1819 |page=8 |via=British Newspaper Archive |access-date=18 September 2024}}</ref> He was buried on 2 September in the graveyard of [[St Mary's Church, Handsworth]].<ref>{{Cite web|url=https://www.freereg.org.uk/search_records/5818e459e93790de6a311110|title=FreeREG database: Handsworth St Mary burial, 2 September 1819: James Watt Esq, of Heathfield, age 83. |access-date=18 Sep 2024 |work=FreeREG |publisher=Free UK Genealogy}}</ref> The church has since been extended and his grave is now inside the church.