Technical drawing of a Watt steam engine, 1787.

The drawing is captioned 'Mr Watt's Patent Rotative Steam Engine. as costructed by Messrs. Boulton & Watt, Soho, from 1787 to 1800. 10 Horse power'. James Watt ((1736-1819) was a Scottish engineer and inventor. He was at the forefront of the development of steam engines and described a steam locomotive in one of his patents. The term 'horse power' was first used by him. Matthew Boulton ((1728-1809), an English engineer, was Watt's business partner. In 1774 they established a manufactory of steam engines in Soho, near Birmingham.