WATT, wee James, Scottish engineer! b. Greenock, Renfrewshire, 19 Jan. 1736; d. Heathfield, near Birmingham, Staffordshire, 25 Aug. 1819. Having determined to adopt the trade of mathematical instrument aspires, he spent a year in Loadon learning the art, in which he attained great dexterity and after his return endeavored to set himself up in business in Glasgow. In this he might not have suc ceeded owing to the opposition of other work ers in the trade. had he not been sppeitteed (1757) mathematical Instrument maker to the university, which was outside of the jurisdic tion of the Glasgow municipality. While thus employed he was also active in preparing sur veys and reports in connection with canal, river and harbor work. It was during this period that he thought of and completed most of his improvements of the steam-engine. The idea of a separate condenser first occurred to him in 1764 and in January 1769 he took out the patent for the improvements of the steam engine in which this idea was applied. Previous to 1Watt's time the cylinder itself had been used as a condenser and the jet of cold water intro duced into the cylinder to condense the steam so reduced the temperature of the cylinder that three times as large a supply of steam (so Watt estimated) was demanded as was really needed. Watt set to work to condense the steam in a separate receptacle. The change was so im portant as to make him almost the inventor of the modern engine. But it was not until the year 1774 that he united with Matthew Bonbon (q.v.), a manufacturer at Birmingham, in order to carry his improvements into execution. In consequence of this he removed to Soho, near Birmingham. where the establishment in which his steam-engines were manufactured soon acquired a European fame. He retired from
the business in 180a when his patent, which had been renewed in 1775 for 25 years, expired. Watt was a Fellow of the Royal Societies both of London and Edinburgh and one of the few natives of Great Britain who have been elected members of the National Institute of France. Besides the expedient of the condenser, Watt made also other improvements in the steam engine. He devised the sim-and-planet gear wheel. made use of the expansion principle to obtain the double engise, applied the governor to the regulation of the speed of steam-engines and invented the throttle-valve. He built the first indicator for drawing a diagram of stems pressure and also patented a fud-saving fur nace, invented copying ink and independently discovered the chemical composition of water. He had a retentive memory and the range of his reading was very wide. Chemistry, archi tecture. music, law, metaphysics and language were the principal subjects which, in addition to physical science and its practical applications, engaged his attention and in all of them his knowledge was wonderfully extensive minute and accurate. (For an account of the improve ments that Watt effected in the steam-engine see &ream ; SrEA Id -ENGIN E) . The siinificance of his work places him among e fore most of inventors. Consult Mnirhead, 'Origin and Progress of the Mechanical Inven tions of James Watt' (1854) • a Li f e' abridged from the preceding (1858) Smiles, of Boulton and Watt' (1865) •, Thurston, 'The Growth of the Steam-Engine' (1879) and an article by Cowper in the 'Transactions' of the Institution of Mechanical Engineers for 1883.