Watt, James

—Born 1736, died 1819. A Scottish engineer and inventor, famous for his improvements in the design of the steam engine. While repairing a model of Newcomen’s steam engine, he discovered the cause of its waste of power, and he devised the separate condenser and the air pump to dy the defect (1765). He patented his imrove steam engine (1769), and entered into artnership with Matthew Boulton for the manuacture of steam engines, in which he continued for twenty-five years (1775-1800). During that time he introduced many important improvements of his own invention, making use of the expansivene of steam to obtain the double stroke (1782). He discovered the composition of water (1782) and projected the screw propeller (1784). At his death a national monument to him was erected in Westminster Abbey. The name watt was given to the unit of electric power in his honor.