Description:Drawing of Coates & Co.’s Horse Gin and Millwork to be replaced by a double-acting engine.
Henry Coates and John Jarratt bought this 7 horse power sun & planet engine for their oil mill at Sculcoates, Kingston-upon-Hull, Yorkshire. This engine was the first double-acting engine that Boulton & Watt sold. It used one of the 15 inch cylinders from James Watt’s experimental double-cylinder engine that he set up at Soho. It was also one of the first (the very first?) to feature a perpendicular motion linking the piston rod and beam, which was precursor to the parallel motion. Note that the drawing shows the engine with the earlier rack and sector motion. The drawing of the horse gin was made by Coates & Co.’s millwright, Richard Savage, and sent to Boulton & Watt to give them an idea of what the engine need to power.
This drawing is part of the Archives of Soho collection, which is held by Birmingham City Archives [Ref. MS3147/Portfolio/5/1]