A clock devised in the mid 17th century which enclosed a balance-controlled mechanism in a metal sphere to indicate the time by means of a band rotating on its circumference past a fixed pointer. The weight of the clock itself was the driving force, and it was suspended from a cord wound round a barrel inside the clock, the clock gradually descending as the hours passed. Winding was accomplished by raising the clock to the top of the cord, and a spring inside the barrel caused the latter to rotate and wind it up. The fusee of conventional clocks was eliminated but a barrel and spring still had to be provided.