Iron chamber clock, probably German, 16th century.
© Science Museum / Science & Society Picture Library
This clock is a smaller version of the type of large striking clocks used in bell-towers and turrets from the beginning of the 14th century. Probably made by a German blacksmith, it is constructed entirely of iron and held together with wedges. The clock has a single hour-hand as was usual at this time; minute-hands were not generally added until the advent of the pendulum in 1656 improved time-keeping sufficiently to make the indications of such a hand of some value. The timekeeping is controlled by a verge escapement and foliot balance, and the striking mechanism is in the shape of a bell hammer on the outside of the bell, which delivers the blow by its own weight.