Contract between Boulton & Watt and British Cast Plate Glas Co, 1788.
© Science Museum / Science & Society Picture Library
This signed manuscript, dated 1st September 1788, is an indenture of agreement between Boulton & Watt and the British Cast Plate Glas Company for the supply of a 14 Horse Power steam engine. James Watt (1736-1819) greatly improved the efficiency of steam engines by adding a separate condenser, preventing the los of energy through steam condensing in the cylinder. His partnership with Matthew Boulton (1728-1809) allowed him to develop the idea along with several other improvements. The Watt engine was crucial to the succes of the Industrial Revolution.