Top, side and end elevation drawings of James Watt's 'Lap' engine, 1788.
© Science Museum / Science & Society Picture Library
Drawings made in 1912 by the Deutsches Museum, Munich. The first recorded steam engine was built in 1712 by Thomas Newcomen. James Watt was asked to improve upon a model of the engine, with his solution being a separate condenser, which he patented in 1769. This, and various other features, meant that Watt and his partner Matthew Boulton had an engine which was capable of driving machinery. This rotative engine was built to power a section of Boulton's own works. It was known as the Lap engine because it drove a number of metal polishing (or 'lapping') machines, and was the first engine ever to be fitted with a centrifugal governor to regulate its speed. The Lap engine is the oldest, essentialy unaltered Watt beam engine to survive intact.