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Jonathan D. Betts
Contributor
Curator of Horology, Royal Observatory Greenwich, National Maritime Museum.
Primary Contributions (31)
![reconstruction of the waterpowered mechanical clock](https://cdn.britannica.com/40/60540-050-6A37C812/Reconstruction-clock-direction-Su-Sung-Joseph-Needham.jpg?w=320&h=240)
Clock, mechanical or electrical device other than a watch for displaying time. A clock is a machine in which a device that performs regular movements in equal intervals of time is linked to a counting mechanism that records the number of movements. All clocks, of whatever form—whether 12-hour…
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