by Jennifer Tann
© Oxford University Press 2004 All rights reserved
Watt, James (1736-1819), engineer and scientist, was born on 19 January 1736 in Greenock, Renfrewshire, the eldest surviving child of the eight children, five of whom died in infancy, of James Watt (1698-1782), merchant, and his wife, Agnes Muirhead (1703-1755), whom he married about 1728. His family were prominent citizens of Greenock, and his grandfather, Thomas Watt (1642-1734), was a well-known teacher there of mathematics, surveying, and navigation. The elder James Watt was also described at various times as a shipwright, chandler, carpenter and joiner, and shipowner; and he served as chief magistrate (or bailie) of Greenock in 1751. His wife was said to be a woman of forceful character and intellect. James and Agnes were buried in the churchyard of Greenock's West Church, and in 1808 their son had a tombstone erected in memory of his 'revered parents'. The inscription on it, written by the younger James, praised his father as: 'A benevolent and ingenious man and a zealous promoter of the improvements of the town' (Williamson, 188).
Childhood, education, and training
James Watt was a delicate child and suffered from frequent headaches during his childhood and adult life. He was taught at home by his mother at first, then was sent to M'Adam's school in Greenock. He later went to Greenock grammar school where he learned Latin and some Greek but was considered to be slow. However, on being introduced to mathematics, he showed both interest and ability. He helped in his father's workshops and began work there on leaving school. He made models at the bench and it is likely that his father intended James to follow him in his business. However, some of the elder Watt's commercial speculations having failed, both James and his brother had to find employment as soon as possible and it was decided that James should go to Glasgow to learn the trade of mathematical instrument maker.
On his arrival in Glasgow in June 1754 Watt stayed with his mother's family. He had brought some carpentry tools and a quadrant with him to Glasgow, which were presumably intended for his first workshop. Through his mother's relative George Muirhead he came into contact in this university city with a number of men who profoundly influenced him. Muirhead had recently moved from the chair of oriental languages to the chair of humanity at Glasgow University. He, John Anderson, and Robert Dick, as well as Joseph Black and Gilbert Hamilton, were all members of the Literary Society of Glasgow. Dr Robert Dick, who became one of Watt's closest friends, had succeeded his father as professor of natural philosophy. It was he who advised Watt to go to London to obtain better tuition in instrument making than could be obtained in Scotland, and he gave him an introduction to James Short, a mathematician and well-known telescope maker of Scottish origin. Watt was now in his twentieth year and, never having served an apprenticeship, could not rank as journeyman; moreover, in order to lessen any financial burden on his father, he needed to learn the greatest amount in the shortest time possible. He arrived in London in June 1755 and had some difficulty in finding a tutor. He spent a short time with a Mr Neale, a watchmaker, but Short introduced Watt to John Morgan, a mathematical instrument maker of Cornhill, and Morgan undertook to instruct Watt for one year in return for 20 guineas and Watt's labour. Watt told his father that Morgan 'can teach me most branches of the business such as rules, scales, quadrants etc.' (Origin and Progress, 1.xxv) and within a month he was making the brass part of Hadley's quadrants. He described his master as: 'as good a character, both for accuracy in his business and good morals, as any in his way in London' (ibid., 1.xxiv).
Watt lived in considerable poverty in London. Anxious to cost his father as little as possible, it is believed he lodged with his master, though not receiving board. But the draughty workshop, poor food, long hours, and painstaking work made him ill. By the year's end he noted: 'I am now able to work as well as most journeymen' (Origin and Progress, 1.xxvi), and, purchasing the bare necessities of materials and tools, he returned to Scotland in August 1756. After a few months' recuperation he went back to Glasgow, where he was given quarters in the university; he apparently found difficulty in establishing himself in the city, as he was neither the son of a burgess nor had served a full apprenticeship. Watt assisted Robert Dick to unpack and to renovate a valuable collection of astronomical instruments, formerly the property of Alexander Macfarlane, which had arrived from Jamaica. He was permitted to open a workshop in the university and to call himself mathematical instrument maker to the university.
Instrument making
Through his interest in natural philosophy Watt came to the attention of Dr Joseph Black, who by 1757 was professor of the practice of medicine. He made various instruments for Black's experimental work, including an organ (built in 1761) and a perspective machine which became the prototype for some fifty to eighty made subsequently. Black described Watt as: 'a young man possessing most uncommon talents for mechanical knowledge and practice' (Origin and Progress, 1.xxxv). Black later wrote that Watt was as 'remarkable for the goodness of his heart and the candour and simplicity of his mind, as for the acuteness of his genius and understanding' (ibid., 1.xxxvi). In 1758 Watt met John Robison, who succeeded Black as lecturer on chemistry in Glasgow and later became professor of natural philosophy at Edinburgh. Both Robison and Black became lifelong friends, testifying, forty years later, on behalf of Watt and his partner Matthew Boulton during the lawsuits against engine patent infringers in 1796-7.
Robison described a visit to Watt's workshop in the university: 'I saw a workman ... but was surprised to find a philosopher as young as myself and always ready to instruct me' (Origin and Progress, 1.xliii). Robison relates how Watt thrived on solving problems and was consulted by many of the young men with scientific interests in and around Glasgow: 'everything became to him a subject of new and serious study. Everything became science in his hands' (ibid., 1.xlvi). Watt learned German in order to read J. Leupold's Theatrum machinarum (1727), and he also learned Italian, sharing his enthusiasm for knowledge with his friends.
As Watt had made little money in his first year he decided that the best opportunity lay in making Hadley's quadrants. He believed that he would need to travel to Liverpool and London to sell them (he did go to London), though he also found some demand in Glasgow. In order to expand his business he required capital, and this was achieved by entering into partnership with John Craig, said to have been an architect. Watt was to receive £35 p.a. in wages and an equal share of the profits. The partners took premises in Saltmarket in Glasgow in 1759. An inventory drawn up at the time shows Watt to have been selling quadrants, compasses, burning-glasses, and microscopes, among other goods. By 1763 the business was prospering, and Watt employed several journeymen and took on apprentices. He moved to Trongate, one of the main streets in Glasgow, and announced in a newspaper advertisement that besides mathematical and musical instruments he offered a variety of 'toys and other goods' for sale (Dickinson, 28). These were the steel ornaments made in Birmingham by a number of manufacturers, including Watt's future business partner, Matthew Boulton. In 1763 Watt acquired a financial interest in the Delftfield Pottery Company in Glasgow. Porcelain manufacture had not long been introduced to Britain and manufacturers were keen to improve the quality. Watt took an active scientific interest in the Delftfield concern, advising on clays, flint-grinding mills, and furnace construction, and eventually he came to have a considerable financial share in the concern. During his canal work he improved the surveying level and produced a new micrometer and a dividing engine. He also devised a drawing machine, though this did not meet his expectations.
Early work on the steam engine
Watt's interest in steam engines dates from about 1759, when John Robison suggested that he consider the application of steam power to road carriages and mining. But the idea was not developed further and, on Robison's departure from Glasgow, the project was abandoned. In the early 1760s Watt began some experiments on the force of steam in a Papin's digester and 'formed [a model of] a species of steam engine' (Origin and Progress, 1.lxvii); but he abandoned the idea due to pressure of other work and in the belief that an engine on the principle employed might suffer the same drawbacks as Thomas Savery's engine--namely, the danger that the boiler might burst, the difficulty of making the joints sufficiently tight, and the loss of much of the power of the steam on the downward stroke of the piston. Nevertheless, he was to describe this mechanism in his 1769 and 1784 patents.
In the winter of 1763-4 Watt was asked to repair the model of a Newcomen engine which belonged to the natural philosophy class at Glasgow University. At this time his knowledge of steam engines was largely derived from J. T. Desaguliers's A Course of Mechanical and Experimental Philosophy (1734) and B. F. De Belidor's Architecture hydraulique (1753). He set about repairing the model engine 'as a mere mechanician' (Origin and Progress, 1.lxix) but found that the boiler could not supply it with steam. Watt identified several problems, of which the wastage of steam during the ascent of the engine piston and the method of vacuum formation in which the system was cooled were two of the most fundamental. He therefore made a new model, slightly larger than the original, and conducted many experiments on it. This led him to his well-known tea kettle experiment in which he discovered the latent heat of steam while not understanding the scientific principle, though he subsequently learned the explanation from Joseph Black.
The theory of latent heat underpinned Watt's experiments on the separate condenser, in which the steam cylinder remained hot while a separate condensing vessel was cold. He is said to have had the inspiration for this device while walking in the environs of Glasgow one spring afternoon in 1765. Writing more than forty years later, he stated that, once the separate condenser was conceived, 'all ... improvements followed as corollaries in quick succession, so that in the course of one or two days the invention was thus far complete in my mind, and I immediately set about an experiment to verify it practically' (Origin and Progress, 1.lxxvi). While in a general sense this was probably true, many practical problems remained to be solved--not all of them by Watt.
In 1765 and 1766 Watt erected several atmospheric engines in Scotland, probably incorporating parts made to his own designs. Work on steam engines was displaced for over a year by civil engineering engagements, but in 1768 he recommenced trials on model engines and in the autumn of 1768 began designing a colliery engine, incorporating a separate condenser and air-pump, for Dr John Roebuck at Kinneil. Roebuck, having studied medicine at Edinburgh and Leiden, had initially settled in Birmingham to practise as a doctor. His interest in chemistry led to a number of discoveries in the refining of precious metals and, together with Samuel Garbett, a member of the Lunar Society in Birmingham, he developed the lead chamber process of sulphuric acid manufacture which permitted large-scale production for the first time. Factories for the production of sulphuric acid were established in Birmingham as well as at Prestonpans in Scotland and, both being highly profitable, Roebuck, who was now settled in Scotland, turned his attention to the large-scale manufacture of iron at Carron. The partners in Carron ironworks were advised on a number of issues by the engineer John Smeaton. The coke-smelting process of cast-iron manufacture was employed and it was this that led Roebuck to take leases of extensive mines on the estate of the duke of Hamilton. It was in the exploitation of these coalmines that Roebuck was to overstretch himself financially.
Roebuck was probably introduced to Watt by Dr Black. It is likely that he quickly recognized the potential that Watt's engine improvements might have for his own industrial interests, but neither he nor Watt anticipated the time that would elapse before the Watt engine was sufficiently developed for manufacture. Watt's first patent for 'A new method of lessening the consumption of steam and fuel in fire-engines' (no. 913) was obtained in January 1769. Roebuck was assigned two-thirds of the invention by Watt in consideration of meeting Watt's debts of almost £1000 (which comprised those incurred during the development of the engine plus the costs of obtaining the patent). Roebuck's financial situation was, however, precarious. Improvements to the Kinneil engine were undertaken in situ under Watt's direction, but in June 1770 Roebuck was declared bankrupt and further development was postponed.
Watt as civil engineer
Watt married his cousin Margaret Miller (d. 1773) of Glasgow on 16 July 1764. Probably in anticipation of this, he left his rooms in the university and took up residence in the city. Needing to provide for his wife and himself, he took an office in King Street and began to undertake surveying work in the summer of 1766, while retaining the instrument-making business. In October 1766 he began a survey for a projected canal between the Firth of Forth and the Firth of Clyde, together with another surveyor, Robert Mackell. He attended parliament in connection with the Canal Bill, remarking: 'I think I shall not long to have anything to do with the House of Commons again--I never saw so many wrong-headed people on all sides gathered together' (Watt to Margaret Watt, 5 April 1767, Boulton and Watt MSS). On the journey to London, in connection with the promotion of the parliamentary bill, he visited Birmingham but did not see Matthew Boulton.
In 1769 Watt was involved in a survey of the River Clyde. He also acted as engineer for a projected canal between Monkland and Glasgow, for which he received a salary of £200 per year, as engineer to the canal, until 1772 when the undertaking faltered through lack of capital. While engaged in these projects he was concerned to improve levelling instruments. But in 1770 he was beginning to experience the tension of conflicting demands--surveying, which was bringing in an income on the one hand, and the urging of Roebuck, his partner, to develop the engine on the other. He told the physician and natural philosopher William Small that the remainder of his time was 'taken up partly by headaches & other bad health & partly by consultation on various subjects of which I can have more than I am able to answer & people pay me pretty well' (Dickinson, 72). He was involved in 1770 in the Strathmore canal survey and in the following year he reported on improvements to the harbour of Ayr and surveyed routes for canals through the isthmuses of Crinan and Tarbet. In 1772 he undertook to survey for a water supply to his native town of Greenock. Surveys for several canals and navigations were undertaken in 1773, including a canal for coal in the Mull of Kintyre, a canal from Hurtet to Paisley, the Forth Navigation, and the Water of Leven. He also undertook a survey of Glasgow docks and harbours.
The last and most significant civil engineering project of Watt's was a survey and estimate for a canal between Fort William and Inverness. He carried this out in 1773 and the canal--later named the Caledonian Canal--was to be successfully constructed in the early nineteenth century. Towards the end of 1784 Watt was approached by James McGrigor, father of his second wife, Anne, to become engineer to the project, but the proposal came to nothing and the canal was finally constructed under Thomas Telford from 1802. Telford acknowledged the quality of Watt's work: 'If I can accomplish this [drawing the utility of the scheme to public attention] I shall have done my duty: and if the project is not executed now, some future period will see it done, and I shall have the satisfaction of having followed you in promoting its success' (Origin and Progress, 1.cxxvi). Having completed his part of the Inverness Canal project by April 1774 Watt was able to turn his mind to Birmingham.
Family and home
In 1767 Watt and his wife had a daughter, Margaret; she married James Miller and died in 1791. A son, James Watt, was born in 1769; he died, unmarried, in 1848. It was on 26 September 1773, when Watt was surveying for a projected canal in the highlands, that he heard that his wife, who was expecting their third child, was dangerously ill. He started immediately for home, only to hear that the child had been stillborn and that his wife had died on 24 September. He was left a widower with two children, the elder of whom was six. In Margaret, he wrote: 'I lost the comfort of my life, a dear friend and a faithful wife' (Dickinson, 82). In 1776 he married for a second time. His new wife was Anne McGrigor (d. 1832), daughter of James McGrigor, a dyer of Glasgow. Anne's father agreed to the marriage but requested that Watt show him the partnership contract between Watt and Boulton. However, no document existed and Watt feared that if he admitted this his prudence would be doubted. He therefore asked Boulton to draw one up: 'I have been obliged to allow him to suppose such a deed did exist but was simple, so what you send must pass for a duplicate'. Watt continued: 'whether a man of the world such as you look upon my present love as the folly of youth or the dotage of age--I find myself in no humour to lay it aside'. Fearing Boulton's ability to be discreet, he chided 'you are a very bad confidant in love affairs, you look upon them as too good things to be kept to yourself' (Watt to Boulton, 3 July 1776, Boulton and Watt MSS). Five days later Watt asked Boulton to come to Glasgow for, though agreements on the marriage had been reached, 'I am afraid I shall otherwise make a very bad bargain in money matters' (Watt to Boulton, 8 July 1776, Boulton and Watt MSS). Watt and his second wife had two children: Gregory (1777-1804) and Janet (Jessy; 1779-1794) ; both died, unmarried, of consumption.
Partnership with Boulton
On his journey to London in 1767 to attend the House of Commons committee on the Forth and Clyde Canal Bill, Watt had passed through Birmingham, intending to see Samuel Garbett, Roebuck's partner. On his return journey he called at Lichfield to see Dr Erasmus Darwin, to whom he revealed his invention of the separate condenser, which, with the air-pump, was the unique element of his fuel-saving improvements to the steam engine. Roebuck was sufficiently sanguine of the potential of Watt's engine to agree to become a partner and, in return for a two-thirds interest in the project, took over Watt's indebtedness to Black, undertaking to pay the cost of a patent.
In 1768 Watt visited Boulton's Soho Manufactory in Birmingham after going to London on business in connection with his intended patent. This time he met Boulton and afterwards wrote: 'I explained to him my invention of the steam engine, and several other schemes of which my head was then full, in the success of which he expressed a friendly interest' (Origin and Progress, 1.cxlvii). Watt would have been impressed by the scale and organization of the factory and in Boulton he met not only an able entrepreneur but also an innovator. Boulton was the first to mechanize the laps for polishing steel, he developed a shaking box for scouring button blanks (a version of which continued to be used into the twentieth century), and later he developed the first flow-production system (key elements of which were mechanized) for the manufacture of coinage and medals. Watt stayed with Boulton for two weeks and on his return to Glasgow in October 1768 suggested that Boulton be offered a one-third share in the patent, possibly with Dr Small. Watt wrote to Boulton, referring to Boulton's wish to be concerned in an engine partnership (a point made clear during Watt's recent visit to him) and setting out the situation with regard to Roebuck.
Roebuck initially responded positively to Boulton's proposed involvement, but then recognizing the potential value of the patent proposed offering Boulton a licence to manufacture Watt's engine in the midlands only. Boulton declined, drawing attention to the need for capital, accurate workmanship, and effective control 'to keep the executive part out of the hands of the multitude of empirical engineers, who from ignorance, want of experience and want of necessary convenience, would be very liable to produce bad and inaccurate workmanship'. He added, 'It would not be worth my while to make for three counties only, but I find it very worth my while to make for all the world' (Dickinson, 54). Roebuck travelled south in September 1769 and Watt expected that a 'proper offer' would be made (Watt to Small, 20 Sept 1769, Boulton and Watt MSS), adding: 'As to the Doctor, he has been to me a most sincere generous friend and is a truly worthy man' (ibid.). Watt experienced a tension between a desire to satisfy Roebuck and himself in the successful completion of the Kinneil engine and the need to earn a living in civil engineering. 'Nothing', he wrote, 'is more contrary to my disposition than hustling and bargaining with mankind, yet that is the life I now constantly lead' (Dickinson, 72).
The period of indecision concerning the steam engine was exacerbated by a number of bank and business failures in 1772-3. Watt reported that Roebuck was now willing to part with his share of the engine on terms which, under better trading conditions, he believed Boulton would have had no difficulty in accepting. By March 1773 Roebuck could no longer meet his financial obligations and had not paid the costs additional to the original £1000 as agreed. Watt discharged these in return for the Kinneil engine, which was dismantled and dispatched to Birmingham.
Yet Roebuck still owned two-thirds of the patent. Boulton, however, was one of Roebuck's creditors. Rather than press for settlement, Boulton postponed negotiating for the patent until he could acquire it from the trustees of Roebuck's estate. This was achieved in August 1773. The death of Watt's first wife in September 1773, occurring in a year of small profit for Watt, and Small's subsequent urging that he go to Birmingham led Watt to decide to leave Scotland and join Boulton at Soho. He arrived in Birmingham in May 1774.
Boulton proposed seeking a parliamentary bill to extend the term of Watt's patent and in May 1775 the act was passed, extending the patent for a further twenty-five years (15 Geo. III c.61). The partnership between Boulton and Watt commenced a month later.
Watt recorded the terms of his partnership with Boulton at the time of his second marriage, in 1776. From this it is clear that Boulton was to bear the financial risk for the expense of the 1775 act and the costs of future experiments, and be responsible for the stock-in-trade as well as the keeping of the accounts, all in return for two-thirds of the property of the invention. Watt was to make drawings, give directions, and make surveys.
On his arrival in Birmingham, Watt lived in Boulton's former house in New Hall Walk but in 1777 he and his family moved to Regents Place, Harpers Hill, a substantial but plain house conveniently near Soho. The Watts maintained an establishment of two maids and a manservant at Regents Place, where Watt did his drawings, correspondence, and calculations, and where his assistants also worked. However, in 1790 he commenced the building in Handsworth of Heathfield, a larger, attractive two-storey house, to the designs of Samuel Wyatt, the architect who had remodelled Boulton's Soho House. He had a garret built over the kitchen to be used as a workshop, while in the yard below there was a forge. As land became available on the heath after enclosure, Watt acquired some and continued to add to it until he owned about 40 acres. He laid out the grounds, built a walled kitchen garden, and erected hothouses and lodges. The house was demolished in the 1920s.
Organization of the engine business
At the beginning of their partnership Boulton and Watt made few engine parts. The engine workshop at Boulton's Soho Manufactory was small and there was no very clear demarcation between those people employed in Boulton's various enterprises and those employed by Boulton and Watt. Materials and parts for engines were obtained from the best rather than the nearest suppliers. Swedish iron was obtained from Birmingham merchants, tubes from Izons of West Bromwich, and piston rods, sometimes, from Jukes Coulson of Rotherhithe. But, above all, the partners depended heavily on the ironmaster John Wilkinson, for it was he who was capable of boring engine cylinders with greater accuracy than any other iron-founder. Even after other iron-founders had installed boring machines similar to those of Wilkinson, they seemed unable to produce goods of such consistent quality as his. In the early years of the Boulton and Watt partnership Wilkinson's advice was sought as well as sometimes given unsolicited. His interests were both as a manufacturer in the supply-chain and also as a customer for Boulton and Watt engines. Indeed, he was one of the largest single customers, installing eleven engines at his Bradley ironworks by the 1790s and at least seven elsewhere. The Coalbrookdale Company, too, was both an important customer and supplier of engine parts. It had been to Coalbrookdale that William Small had looked when seeking parts for the Kinneil engine before Watt had moved to Birmingham, and this company and its associates became Wilkinson's chief rival in the supply of engine parts. Even when the customer for a particular engine was as eminent an ironfounding company as the Walkers of Rotherham, Watt was cautious about permitting them to cast all their own engine parts. In general, Boulton and Watt subcontracted the manufacture of parts to firms of their own choice, most of them in the midlands region. Only piston rods seem to have been forged as far afield as Whitehaven, Workington, and Rotherhithe.
During the 1780s and early 1790s, while continuing to depend on subcontractors for many engine parts, Boulton and Watt increased both the range of operations and the capacity of their engine workshop at Soho Manufactory and by 1793 were making over 50 per cent by value of their engine parts. The reasons for this move towards the production of complete engines may have been partly financial, the partners wishing to secure to themselves the profits of forger and founder as well as those of consulting engineer. They claimed to make no profit on the parts made by other founders and, while they probably did not add a percentage to Wilkinson's castings, Boulton was certainly of the view that the partners should receive commission on all parts made by subcontractors. The main reason, however, for extending the production of engine parts at Soho Manufactory was probably an acceptance of the considerable organizational problems with subcontracting in the late eighteenth century. The unpredictability of completion time for an engine was a major difficulty, as were problems of transporting large castings by canal. Moreover, quality control was a prime concern. While standardization was only slowly introduced by Watt to engine production during the 1780s, and while a lack of it constrained output and increased costs, this drawback was at least partly offset by ensuring that all parts were made to the tolerances demanded by Boulton and Watt. There were often advantages in subcontracting, notably the smaller capital base from which the partners were able to operate. Moreover, Watt could continue experimental work while subcontractors bore a larger proportion of manufacturing risks. For the first few years each engine manufactured was largely custom-built. Sizes were relatively standardized but improvements were incorporated as developments were made by Watt and suggestions made by employees as well as some friends and customers.
Watt's role was largely that of development, design, and drawing, as well as working on patent specifications. He also visited customers, notably in Cornwall. The partners employed a small group of itinerant mechanics who were responsible for the erection of engines for their British customers. Skilled mechanics were in short supply and were not above exploiting their scarcity value. It was partly in order to protect the reputation of the firm that Boulton and Watt initiated a protocol of customer visits: when either of the partners or a senior employee visited an area in which they had several customers, attempts were made to inspect each engine and to offer maintenance guidance.
For the term of the extended patent a significant contribution to Boulton and Watt profits was derived from the royalty imposed on users of the Watt engine. For reciprocating engines this was computed at one-third of the savings in fuel effected by Watt's engine in comparison with a Newcomen engine capable of performing an equivalent amount of work. Premiums on rotative engines were charged at £5 per horse power per year in the provinces and £6 in London. Towards the end of the term of their patent the partners usually commuted the annual royalty to a lump sum payable upon purchase of the engine.
A shortage of capital inhibited Boulton in his desire to establish a separate engine factory, which had been his stated intention on first meeting Watt and conducting negotiations with him. But the discovery that Wilkinson had been pirating Watt's patent, together with the knowledge that the patent had only five and a half more years to run, and coupled with the fact that the partners had already extended their own repertory of engine parts, led to their making a quick decision in 1795 to establish a separate engine foundry. Watt seems to have played little part in the design of the foundry, which was built adjoining the Birmingham Canal near to adequate supplies of coal. It was intended that cylinders, pumps, and all other engine parts would be made there. It was also acknowledged that the partners would aim to make improvements to the engines, a task which had been more difficult while they depended on subcontracting much of the foundry work. They perceived further advantages in being able to make engines more cheaply and in a shorter time, as well as in keeping engines in stock. Thus, Soho Foundry was opened in 1796. Watt gradually withdrew from active participation in the business, and it was managed by his son, James Watt, and Matthew Robinson Boulton. The elder Watt retired in 1800.
Further patents
The engine manufacturer who could solve the problem of rotary power generation other than by means of a water-wheel in the early years of the industrial revolution was likely to reap considerable financial reward. As early as 1765-9 Watt had devised a steam wheel to generate rotary motion. Both he and, later, Boulton had in mind a hollow annular chamber mounted on a shaft, and in 1774-5 Watt laid drawings of one before a committee of the House of Commons.
It is clear that a steam wheel was made and set to work at Soho in 1774, and a year later Boulton reported that another one was being developed. But in the early years of the partnership Watt was kept busy with reciprocating engines, and plans for rotary power were laid aside. Yet Boulton continued to draw attention to the opportunities, pointing out in 1776 that he could dispose of a hundred wheel engines, were they available.
The opportunities were also perceived by others. Robert Cameron, an employee who later became an independent engineer, approached Boulton with an idea. Watt discouraged Boulton, and Cameron's ideas were not proceeded with. But as early as 1779 a Newcomen engine had been fitted with rotary motion at a Birmingham flour mill owned by James Pickard, who in 1780 replaced the ratchet-and-pawl mechanism with a crank patented in the same year (no. 1263).
It has been alleged that the idea of the crank had been stolen from Watt and there is evidence to substantiate this, though Watt's stated reason for not patenting or developing rotary power at this time--pressure of work--was weak. It is more likely that he still needed to be persuaded of the usefulness of rotative power. However, under increasing pressure from Boulton he was persuaded to do so and, probably not wishing to contest the crank patent, developed, instead, 'sun and planet motion', which was patented in 1781 (no. 1306). The firm used this mechanism on all its rotative engines until 1794, when Pickard's patent expired, and in some cases for several years afterwards, after which time it also employed the crank, which was a far more effective way of generating rotative power.
In 1782 Watt was granted a patent for several major improvements to his engine (no. 1321). Of greatest significance was rotative motion. Other improvements included the use of the expansive principle and the double-acting engine, as well as a means of connecting the piston rod and beam for use in double-acting engines. Of these improvements it was the double-acting engine that had potential application, fuel savings in the expansive engine being found, in practice, to be too small to warrant development. The rack-and-sector connection for the double-acting engine was superseded by parallel motion, which was patented by Watt in 1784 (no. 1432) together with various other improvements, including the application of steam engines to wheel carriages. Of all his inventions it was parallel motion that appears most to have pleased James Watt.
Boulton and Watt were a natural target for industrial espionage. Employees talked or were bribed, and over-curious visitors would make drawings when possible. In turn the partners were vigilant in tracking down patent infringers. Friends described new engine installations around the country, while faithful employees such as William Murdock reported on anything suspicious, particularly in Cornwall. The partners sought patent protection and privileges overseas, some form of privilege being obtained in France, Spain, and the Netherlands. Discussions were also initiated regarding patents in the United States and the Austrian empire but none was granted.
The market for engines
Estimates for the number of engines manufactured by Boulton and Watt for the British market during the term of their patent have varied considerably, ranging from 318 to 512. While the smaller figure is a considerable underestimate, the latter includes a number of double counts; the most likely figure is 449 engines. Demand for the Watt engine was low at first but so too was the company's capacity to produce the requisite drawings and patterns for the subcontracting of parts. Until 1783 all the engines built were reciprocating ones, but thereafter rotative engines appear in the orderbooks. These were smaller engines and up to eighteen rotative engines per year were produced before the opening of Soho Foundry. From the opening of the foundry in 1796 the number of rotative engines manufactured increased markedly, fulfilling Boulton's expectations of a rapidly increased rate of engine production.
While some writers have alleged that no steam engine manufacturer was capable of supplying workable engines with a nominal rating of over 100 hp until the nineteenth century, when reciprocating engines are converted to a horsepower equivalent it is clear that some of the largest double-acting pumping and blowing engines were generating over 100 hp equivalent. By the end of 1800 Boulton and Watt engines totalling approximately 11,205 hp had been erected in Britain at an average size of just under 25 hp per engine.
A large proportion of the pumping engines sold by Boulton and Watt during the first ten years or so of their partnership was supplied to the Cornish copper and tin mines. The Cornish activities of the partners are significant for several reasons: first, for the sheer scale of their operations, both in the number and size of engines supplied to the region as well as the proportion of the partners' total profit contributed by Cornish engines; and second, because Boulton and Watt became large investors in Cornish mines to enhance demand for its engines at a period when the Cornish copper industry was subject to considerable fluctuation. The demand for the Boulton and Watt engine in Cornwall was enhanced by the fact that the mines had reached a depth from which neither water engines nor the Newcomen engine could extract water adequately and consequently the mines were in danger of being flooded out. Moreover, Newcomen engines consumed greater quantities of coal than the Watt engine. Thus Cornwall provided an ideal setting for a demonstration of the considerable savings in coal that Watt's engine would effect over a Newcomen engine of comparable power. Between 1777 and 1801 forty-nine Boulton and Watt engines were erected in Cornwall. During the early 1780s the proportion of Boulton and Watt's engine business accounted for by Cornwall ranged from as low as 5 per cent to as much as 80 per cent in any one year.
Until 1784 all the Watt engines erected on the Cornish mines were single-acting, but in that year both the double-acting pumping engine and the rotative engine were introduced to Cornwall. In all cases rotative engines were of a lower horsepower equivalent than the pumping engines. A distinguishing feature of the partners' Cornish business was the extent to which engines were moved. While engine moving was not unique to the Boulton and Watt engine (for it had been a regular occurrence with its Newcomen predecessors), in no other region were nearly as many of these engines moved. Out of the total of forty-nine recorded Boulton and Watt engines in Cornwall, only thirteen appear not to have been moved. Some engines were moved three times or more.
A significant aspect of Boulton and Watt's marketing strategy was the identification of key innovating entrepreneurs in different industries. Some, such as Richard Arkwright, were approached by a partner intent on selling an engine. Other manufacturers approached Boulton and Watt. The result was that in a number of key industries prospective customers could be encouraged to follow a precedent already set by the larger innovators.
The great market for rotative power was, as Boulton had anticipated, the textile industry--in particular, cotton. While Arkwright, patentee of the water frame, was not among the first customers for Watt engines in cotton spinning (though in time he was), other leading entrepreneurs in water frame spinning provided the impetus, and with the introduction of mule spinning the number of orders escalated. The application of steam power to the wool textile industry was slower. Steam power was applied to worsted spinning relatively soon after the invention of the water frame, since a modified form of the frame could be applied to the longer filaments employed in this sector of wool textile manufacture. In woollen manufacture steam power was applied to carding and roving first, the diffusion of steam power in this sector of the wool textile industry being assisted by the early adoption of a Boulton and Watt steam engine by a leading Yorkshire innovating entrepreneur, Benjamin Gott. In both the cotton and wool textile industries a by-process of the use of steam engines was the employment of steam from the boilers to heat dying and bleaching vats.
The application of the Watt engine to manufacturing industry was assisted in two sectors by the direct financial interest the partners took in these sectors severally or together. Among the various business enterprises run by Boulton at Soho Manufactory was the Soho Mint. Besides supplying British and overseas customers with coin, he used the mint as a laboratory for the design of a flow-production system for minting, employing steam power in several of the processes. Within a few years he was accepting orders for complete mints to be supplied to various overseas customers as well as to the Royal Mint, and the steam engines would be supplied by Boulton and Watt. An experimental corn mill, driven by steam power, was set up at Soho Manufactory and this formed the prototype for the Albion steam corn mill at Blackfriars in London, in which both Boulton and Watt, besides others, were shareholders. This, driven by two Boulton and Watt engines, was the largest steam-driven corn mill in the world at that time. It was seen by a number of British visitors and those from overseas, some of whom ordered engines for steam corn mills; on several occasions they ordered a total package--the milling machinery to be supplied by John Rennie, the London-based engineer who had been, for a while, a Boulton and Watt employee.
In addition to the home market, Boulton and Watt supplied engines to a number of overseas customers. The first foreign order was received as early as 1778, only three years after the partnership had commenced. Two further engines were ordered in 1779 and then there was a six-year interval before any further orders were obtained. Between 1785 and 1799 twenty-one engines were ordered, which made a total of twenty-four, comprising approximately 773 hp, at the expiry of Watt's patent, of which six engines were countermanded. The majority of the orders were from countries in western Europe: France, Germany, Italy, Spain, the Netherlands, Austria, and Sweden. Two engines were ordered for Russia and one (later countermanded) for India. The applications ranged from sawmilling, flour milling, coalmining, land drainage, and minting to town water supply.
Impact of the patents
One of the consequences of the extension of Watt's 1769 patent for a term of twenty-five years from 1775 was that it hindered, at least in principle, developments in steam power technology for a total of thirty-one years during a period of accelerated economic growth and technological change. While Watt was granted other patents subsequently, they all concerned refinements and additions to his basic engine principle patented in 1769. So all-embracing were the terms of his 1769 patent that almost any modification, patented or not, which was incorporated in an engine of another make and which had any contrivance that operated in lieu of a separate condenser and air-pump, could be deemed an infringement. There was an increase in the number of patents taken out for steam engines in the period covered by Watt's patent. Some may have been taken out with the intention of bypassing Watt's. Others were for improvements and modifications which, had they been made widely available, might have made significant advances to steam engine technology. For the first few years of the Boulton and Watt partnership the partners took little notice of other engine patentees, but by 1790 piracy had increased to the extent that Boulton directed a legal friend to obtain copies of drawings and specifications of all the patents for steam engines taken out since the beginning of that year. It was only after considerable deliberation that the partners decided to contest significant pirates, being prepared ultimately to pursue them to the highest British courts. While their anti-piracy campaign did not commence in earnest until the early 1790s, earlier reports of the activities of two competitors had prompted investigation and discussion of possible legal action in the 1780s. The largest single pirate was John Wilkinson, the ironmaster responsible for casting the early Watt engine cylinders. The extent of his piracy was divulged by his brother William after a quarrel. The other pirate of whom Boulton and Watt had most to fear was Jonathan Hornblower jun., who had designed a double-cylinder engine and was directing his efforts particularly towards the Cornish mine adventurers. In the face of overwhelming evidence of his piracy John Wilkinson capitulated, as did most of the other pirates. One partnership, J. C. Hornblower (elder brother of Jonathan Hornblower jun.) and J. A. Mabberley, then manufacturing engines in London, was pursued relentlessly through the courts, and it was not until 1799 that the court of king's bench upheld Watt's patent and the partners were able to collect the unpaid premiums owed to them.
Watt the scientist
While Watt was undoubtedly a craftsman of the highest order he was also a philosopher and scientist. As an instrument maker he had a remarkable diversity of scientific interests, from building an organ and mastering the theory of harmonics from a book, to investigating new methods for the manufacture of alkali from common salt; and he nearly anticipated Henry Cavendish and Antoine Lavoisier in identifying the composition of water. He earned honours in international circles in Russia, the Netherlands, and France, and was elected to the Royal Societies of London and Edinburgh. He conducted a voluminous scientific correspondence. Dr Joseph Black of Glasgow and Edinburgh universities was one of the most outstanding scientists of his day--someone who believed that chemistry was not an art but a science which had both philosophical and utilitarian objects. Black did not inhabit an intellectual ivory tower but recognized the usefulness of his work to practical ends, acting as adviser to a number of industrial concerns. Watt corresponded extensively with him on the subject of the latent heat of steam, as well as on the development of synthetic soda manufacture, ceramics firing, mineralogy, and scientific instruments--all intermixed with domestic details.
Watt's relationship with Dr John Robison was, perhaps, partly influenced by the fact that both men were of similar ages. Robison had intended to have a naval career, but after having been present at the capture of Quebec, he returned to academic life. Like Black, he was close to industrialists and gave them advice on chemical or engineering matters. He was described as 'one of the greatest mathematical philosophers of his age' (Dickinson and Jenkins, 16), and he suggested to Watt that a textbook should be written for mechanics to enable them to advance in their careers: 'the running text should be intirely [sic] practical, containing no science, but only the results of scientific investigation' (Musson and Robinson, 183). Robison, like Black, was indefatigable in his support for Watt, searching in libraries for materials on steam engines when Watt was based in Glasgow. On Robison's death in 1805 Watt wrote: 'He was a man of the clearest head and the most science of anybody I have ever known' (Dickinson and Jenkins, 75).
Someone else who influenced Watt was Dr James Hutton, the Scottish geologist, who had studied medicine at Edinburgh, Paris, and Leiden. In 1756 he established a sal ammoniac factory in Edinburgh and published various works on geology. In their partnership Boulton and Watt shared interests in chemistry and mineralogy as well as steam engines. To depict the engine partnership as one in which Watt provided the science and Boulton the finance and business acumen would be to stereotype both partners inappropriately. Boulton did much work on the engine in Watt's absence and conversely Watt could be decisive in financial matters.
Besides the attraction of partnership with Boulton in Birmingham, Watt was attracted by the circle of scientifically minded friends that Boulton had gathered around him at Soho. The Lunar Society, probably the most important (though informal) provincial philosophical society, was established in 1766. Boulton, Erasmus Darwin, James Keir, and William Small met for dinner on the Monday nearest to the full moon. Watt became a member on his arrival in Birmingham and the membership eventually increased to fourteen, a number of whom were to become fellows of the Royal Society.
While there were many literary and philosophical societies in the provinces during the early years of the industrial revolution, its informality set the Lunar Society of Birmingham apart. The conviction that conversation was a fertile source of self-improvement drew men together in clubs. The scientific interests of the members ranged broadly across the natural and physical sciences as well as engineering. In addition, many of the members shared interests in education and some had interests in the arts. Three members of the Lunar Society, including Watt, were Scotsmen and three others had been educated at Scottish universities. Watt maintained particularly close links with science in Scotland through both kinship and friendship. He began to prosper in the engine partnership with Boulton, and as his fame grew it was to his Scottish friends that he turned for help in the defence of his patents-at-law.
Of all the interests of the Lunar Society members it was perhaps instrumentation for measurement that drew the largest number of members together. Watt, with his interest in the theory of latent heat and its practical application in steam engines, was interested in the measurement of heat and the expansive properties of steam. Linear measurement was also a subject of interest to Watt through his previous career in surveying. It was their discussions on advances in instrumentation that led to a particularly close relationship between Watt and Dr William Small.
One of the most significant examples of the Lunar Society members' activities in support of applied research was in the field of medicine. The driving force was that of consumption. Watt's daughter Janet (Jessy) died of consumption in 1794 at the age of fifteen and his son Gregory died of the same disease in 1804. William Withering, one of the members of the Lunar Society, suffered from it, as did the wife and daughter of Richard Lovell Edgeworth, another member. Members of the society supported the proposal of Dr Thomas Beddoes for a pneumatic medical institute in 1793. It was proposed to establish a laboratory and hospital where newly discovered gases could be clinically tested to assess their curative properties, particularly in relation to consumption. But by the time the institute was opened in 1799 belief in the curative powers of gases had begun to decline and, though the plans continued, Humphry Davy being recommended by Gregory Watt as assistant for the laboratory, the direction of the focus of the institute's activities became one of preventative medicine rather than curative. James Watt had other interests in health, notably in the relief of atmospheric pollution in industrial towns. He patented a smoke-consuming furnace in 1785 which attracted the attention of leading members of the community in rapidly industrializing towns such as Liverpool.
The large amount of correspondence occasioned by Watt's business and scientific interests and the laborious method of making handwritten copies of all important letters prompted him to invent a mechanical method of letter-copying which was patented in 1781. A gelatinous ink was used for writing, and, on completion of a letter, a sheet of damp, unsized paper was placed on the original and even pressure was applied until the ink came through. The press was employed extensively by Boulton and Watt, not only for letters but also for drawings. J. Watt & Co. was established to manufacture and sell the copying press. Watt held a 50 per cent share in the business and Boulton and James Keir 25 per cent each. A number of Lunar Society members were interested in the mechanism, including Erasmus Darwin and Joseph Priestley. The copying-press business was directed by Keir for a year or so before he left to establish an alkali manufacturing plant. J. H. Magellan was agent for continental sales of copying presses as well as steam engines.
Retirement
In 1798 Watt had purchased a property with a farmhouse at Doldowlod, near Rhayader in Radnorshire. The farmhouse was converted into a comfortable country house where he quite frequently spent the summer months. His retirement was clouded by the loss of his son Gregory in 1804, a young man who seemed 'to have all the genius of his father with a great deal of animation and ardour, which is all his own' (Dickinson and Jenkins, 73). Watt wrote 'We ... cannot help feeling a terrible blank in our family' (Origin and Progress, 2.247).
In retirement Watt and his wife travelled a good deal. In 1802 they journeyed up the Rhine to Frankfurt and on to Strasbourg, returning to England via Paris. He visited Scotland frequently, and was particularly fond of Edinburgh. His dry humour, and the Scots accent that he never lost, made him welcome north of the border.
A number of Watt's friends died at the turn of the century. Josiah Wedgwood had died in 1795, Black in 1799, Erasmus Darwin in 1802, and Joseph Priestley in 1804. John Robison died in 1805. But a greater loss was that of his partner, Matthew Boulton, who died in 1809 at the age of eighty-one. Watt well knew the debt he owed to Boulton: 'few men have had his abilities and still fewer have extended them as he has done' (Watt to M. R. Boulton, 23 Aug 1809, Boulton and Watt MSS).
Watt deeply felt the loss of some of his friends from the Lunar Society. And he is said to have been haunted by the fear that his mental faculties were failing. There is much evidence to the contrary: he was consulted by the Glasgow Waterworks Company in 1811 and took pleasure in inventing as a hobby rather than a business. The problem which concerned the directors of Glasgow Waterworks was how to convey the filtered water across the River Clyde to the company's pumping station at Dalmarnock. Watt supplied a drawing for a flexible water main on the analogy of a lobster's tail. The installation was successful, and when Watt declined to accept any payment for his services the directors of the waterworks presented him with a service of silver plate. Further evidence of his continued inventive powers in his old age is the sculpturing machine copying irregularly shaped three-dimensional objects such as busts. He spent a great deal of his spare time in the garret workshop at Heathfield. By April 1809 he had made considerable progress and claimed that he could do two or more copies at once. He appears to have received much friendly assistance from William Murdock of the Soho works. Experiments continued and in 1814 he considered taking out a patent for the invention. He drafted a concise specification but does not appear to have taken the matter any further. At his death in 1819 he was still continuing to develop two machines--a proportional sculpturing machine and an equal sculpturing machine. A baronetcy was offered to him but he declined the honour. He was also asked to be high sheriff of Staffordshire and later Radnor but declined these as well.
Personality and death
In appearance Watt was somewhat above medium height, with a spare figure and a pronounced stoop of the shoulders. His eyes were grey and his hair turned white early in life. It is known that he was not an early riser and required ten hours' sleep each night. For much of his life he suffered from severe headaches; and he took snuff and smoked tobacco. In his portraits he is shown as a serious man deep in thought; he was also cautious and modest, with a tendency to be self-deprecatory.
Watt's correspondence shows him to have been a man assailed by self-doubt, whose strengths lay in radical and elegant solutions to specific scientific and engineering problems. He was far less focused on business opportunities or wider issues. His reluctance to develop the rotative engine, for instance, cost the partners the opportunity to use the crank before the 1790s. Watt was greatly supported by his Scottish friends, though the support appeared to be one-way on occasion. He was, however, always generous in sharing scientific ideas while being an emphatic protector of his patented intellectual property. Nevertheless, his partner, Boulton, bore the financial risks of the business. As a father, he was less liberal than Boulton, though he was clearly devoted to his children, and was devastated by the deaths of Jessy and Gregory.
Watt died at Heathfield in Handsworth, Birmingham, on 25 August 1819 and was buried beside Matthew Boulton in St Mary's Church, Handsworth, on 2 September. His wife, Anne, and son James were appointed executors of his estate. In his will he requested that he might 'be interred in the most private manner without show or parade as soon after my decease as may be proper' (Dickinson and Jenkins, 79). He left his wife £1400 p.a. and Heathfield for life, and to his son the residue of the estate which included all documents, drawings, and tools. The will was proved on 13 October for a sum in excess of £60,000. In 1824 Lord Liverpool initiated a public subscription for a memorial sculpture by Francis Chantrey in Westminster Abbey. It additionally had an inscription, written by Henry Brougham, which read: 'James Watt ... enlarged the resources of his country, increased the power of man and rose to an eminent place amongst the most illustrious followers of science and the real benefactors of the world.' The coat of arms with the motto Ingenio et labore, borne by the Watt family and shown on many of the monuments erected to Watt's memory, was granted in 1826.
Significance
Between 1775 and 1825 the Watt engine was adopted by many of the most eminent leaders of the manufacturing industry and canal transport. To Victorian and later writers the steam engine was almost synonymous with industrial growth and progress. Watt's near contemporary, the engineer John Farey, thus argued that the engine was the most important invention 'in the history of the arts' (Farey, 473). In his seminal essay, The Industrial Revolution, 1760-1830, T. S. Ashton in 1948 accorded a similar role to the engines produced by Boulton and Watt: 'The new forms of power, and no less, the new transmitting mechanisms by which this was made to do work previously done by hand and muscle, were the pivot on which industry swung into the modern age' (Ashton, 58).
Although the exclusive nature of the 1769 patent and its extension for twenty-five years undoubtedly hindered other developments, steam power was not the most widely employed prime mover until well into the nineteenth century. The cultural impact of the Watt engine far exceeded its economic impact. Indeed, it has been estimated that the saving effected by the Watt engine by 1880 was no more than 0.11 per cent of current national income, or, to put it another way, without the engine the industrial revolution would have been held up by no more than one month.
Watt, a modest man, would not have approved of the role in which he was cast by his son James and others from the late 1820s onwards--namely, the inventor as hero. He was included in the hall of Scottish heroes in the Wallace monument erected near Stirling in the 1860s, and his name became a byword for Scottish ingenuity and assiduity. The Watt Institution and School of Arts in Edinburgh was in 1852 named after him; this was later amalgamated with the George Heriot Trust and subsequently became Heriot-Watt University. His life, as depicted by Samuel Smiles and later writers, became a paradigm of mechanical genius.
Although his steam engine may not have triggered off industrialization in the manner traditionally stated, it was still of profound cultural and economic significance and has to be viewed against the backdrop of the Scottish Enlightenment. And of Watt's humanity and of his genius as an engineer there can be little doubt.
JENNIFER TANN
Sources
The origin and progress of the mechanical inventions of James Watt, ed. J. P. Muirhead, 3 vols. (1894)
J. P. Muirhead, The life of Watt, with selections from his correspondence, 2nd edn (1859)
G. Williamson, Memorials of the lineage, early life, education and development of the genius of James Watt, ed. J. Williamson (1856)
H. W. Dickinson and R. Jenkins, James Watt and the steam engine (1927)
E. Roll, An early experiment in industrial organisation, being a history of the firm of Boulton & Watt, 1775-1805 (1930)
J. Tann, ed., The selected papers of Boulton and Watt, 1 (1981)
J. Tann and M. J. Breckin, 'The international diffusion of the Watt engine, 1775-1825', Economic History Review, 2nd ser., 31 (1978)
J. Tann, 'Fixed capital formation in steam power, 1775-1825', Studies in capital formation in the United Kingdom, 1750-1920, ed. C. H. Feinstein and S. Pollar (1988)
R. E. Schofield, The Lunar Society of Birmingham (1963)
E. Robinson and A. E. Musson, James Watt and the steam revolution (1969)
J. Tann, 'Mr. Hornblower and his crew: steam engine pirates at the end of the 18th century', Transactions [Newcomen Society], 51 (1979-80), 95-109
Partners in science: letters of James Watt and Joseph Black, ed. E. Robinson and D. McKie (1970)
E. Robinson, 'Training captains of industry: the education of Matthew Robinson Boulton [1770-1842] and the younger James Watt [1769-1848]', Annals of Science, 10 (1954), 301-13
A. E. Musson and E. Robinson, Science and technology in the industrial revolution (1969)
G. N. von Tunzelmann, Steam power and British industrialization to 1860 (1978)
J. Farey, A treatise on the steam engine (1827)
T. S. Ashton, The industrial revolution, 1760-1830 (1948)
H. W. Dickinson, James Watt, craftsman and engineer (1936)
S. Smiles, Lives of Boulton and Watt (1865)
S. Smiles, Lives of the engineers, 3 vols. (1861-2)
D. J. Bryden, Scottish scientific instrument-makers, 1600-1900 (1972)
Birm. CL, Boulton and Watt collection
DNB
Archives
Birm. CA, corresp. and papers | Birm. CA, corresp. with Boulton family
Birm. CA, Muirhead MSS
Hergest Trust Archives, Kingston, Herefordshire, letters to Mr and Mrs James Crummer, Joseph Davies, and Richard Banks
U. Edin. L., letters to Joseph Black
Likenesses
C. F. von Breda, oils, 1792, NPG [see illus.]
W. Beechey, oils, 1801, Birmingham Museums and Art Gallery
P. Rouw, wax sculpture, 1802, NPG
T. Lawrence, portrait, 1813
C. Turner, mezzotint, pubd 1815 (after T. Lawrence), BM
F. L. Chantrey, marble statue, 1825, St Mary's Church, Handsworth, Birmingham
F. L. Chantrey, marble bust, Scot. NPG
F. L. Chantrey, marble statue, U. Glas.
F. L. Chantrey, statue, Westminster Abbey
F. L. Chantrey, statue, Scot. NPG
G. Dawe, pencil and wash drawing, Scot. NPG
J. Graham Gilbert, oils, U. Glas.
Henning, portrait, Scot. NPG
H. Howard, oils, NPG
H. Raeburn, oils, Hunt. L.
oils, Scot. NPG
Wealth at death
over £60,000: will, H. W. Dickinson, James Watt, craftsman and engineer
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