'Watt's first experiment with steam', c 1745.
© Science Museum / Science & Society Picture Library
Engraving by James Scott, after a painting by Robert William Bus. The Scottish engineer and instrument maker James Watt (1736-1819) is shown here, as a child at the tea table, observing a steaming kettle. Watt went on to invent the modern steam engine, which became the main source of power in British textile mills during the Industrial Revolution. His engine had a separate condenser through which steam from the cylinder was pased and cooled, allowing the engine to remain hot, thus reducing fuel consumption. The SI (international standard) unit of power, the watt (W), is named after him. Published by the Lloyd Brothers, 1849. Dimensions: 496mm x 550mm.