James Watt, Scottish engineer, late 18th century.
© NRM / Pictorial Collection / Science & Society Picture Library
Painting on tile made in 1886 by John Eyre of Matthew Boulton (1728-1809) and James Watt (1736-1819). One of a series of tiles produced by Doulton and Co. Watt invented the modern steam engine, which became the main source of power in textile mills in Britain. His engine had a separate condenser in which steam from the cylinder was pased and cooled allowing the engine to be kept hot. This reduced fuel consumption and saved time. Watt formed a partnership in 1773 with works owner Boulton to produce steam engines. By the early 19th century over 500 Boulton and Watt engines were being used in Britain's mines and factories. The SI (international standard) unit of power, the watt (W), is named after Watt.