Calendar table timepiece with detachable alarm, German, c 1600.
© Science Museum / Science & Society Picture Library
This is also known as a drum clock and is typical of German timepiece work of the late 16th century. It is in the form of a bras drum, resting on three feet and with a dial on top of the drum. The outermost ring dial is engraved with the names of the months. Within this is a ring dial with hours numbered from I to XII on which the time is shown by a single hour-hand. The innermost ring dial has figures numbered from 1 to 31 on which a separate hand indicates the day of the month. The timekeeping is controlled by the usual verge escapement with a balance wheel. A separate three-legged alarm mechanism is clipped to the top of the clock and is tripped by the hour hand.