A heavy body suspended from a fixed point from which it can swing freely to and fro. A clock pendulum comprises the suspension, which can be a spring, knife-edge or a wire, the generally cylindrical metal or wood rod, and the bob, which is the weight at the end of the rod.
Galileo used a pendulum in his astronomical observations (1595). Huygens expanded on Galileo's theory to build his pendulum clock in 1657. It was a further twenty years or so before his invention reached the Jura, where the Mayet brothers, both blacksmiths, applied it to what appears to be the ancestor of the Comtois clock.