Glossary/Water Clock
Water Clock
A water clock is any clock that keeps a record of passing time through the use of water.
The earliest water clocks were Egyptian stone bowls with sloping sides and a small orifice at the bottom through which the water could leak in predictable quantity, drawn down by the force of gravity. After filling, the decreasing water level inside shows the passing of the hours against a scale inscribed in the wall of the dish. Different scales are for the different temporal hours of different months. Introduced into Rome and Greece and gradually made more and more elaborate in the early centuries anno domini, with floats that moved, figures pointing to scales, and mechanisms striking bells, but not much improved in accuracy. The water clock reached its climax in the elaborate clock of Su Sung in China.