science · 20 November 1751 · 273 years ago
death
Died 20 Nov 1751 (born c. 1674).
Eminent English watchmaker who was first a partner with, then successor to Tompion's business. Graham improved Tompion's cylinder escapement. In addition, he invented (c. 1715) the dead-beat escapement (in which the escape wheel remains stationary when not moving forward.) Using these two developments together, Graham's timepieces ran with an accuracy unsurpassed for more than a century and a half. He also made astronomical devices for Edmond Halley, James Bradley, the French Academy of Sciences, and Charles Boyle, 4th Earl of Orrery. For the latter, he designed a clockwork model showing the motions of the planets around the Sun, thereafter known as an orrery. He invented a beam caliper with a micrometer screw.
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