Joseph Williamson

Williamson was made a Free Brother of the Clockmakers' Company in 1686 and went on to become Master in 1724. He is thought to have made watches for Philip V of Spain. In 1720 Williamson claimed to have invented the equation mechanism for clocks, which shows the variation between solar and mean time.

The first equation clock known to have used a differential for addition was made by Joseph Williamson in 1720. This clock is also the earliest device definitely known to have used a differential for any purpose anywhere, although previous ones have been postulated.