Salomon Coster's Pendulum Clock After Christiaan Huygens

A small wall clock in an ebony case, its velvet-covered dial swung open to show the movement. Christiaan Huygens worked out how to regulate a clock with a pendulum, and the Hague clockmaker Salomon Coster built the first pendulum clocks to his design under a 1657 patent. The pendulum made clocks far more accurate than anything before. Only a handful of Coster's clocks survive; this one, signed by Coster, was photographed on display at the Rijksmuseum in Amsterdam in 2015. The oldest dated example, from 1657, belongs to Rijksmuseum Boerhaave in Leiden.