They had but two measures of time—the clepsydra, or water-clock, and the sun-dial.
Like the sun-dial and the clepsydra, the hour-glass is older than we know.
The principle is the same as that of the simplest form of clepsydra.
The Djyotisha also teaches the art of constructing a clepsydra, or water-clock.
The water-clock, or clepsydra, has been known to the Chinese for centuries.
This water clock was called a clepsydra, the name being taken from two Greek words meaning 'thief of water.'
Each of the sides had a sort of dial, and the building formerly contained a clepsydra or water-clock.
Clepsydra, klep′si-dra, n. an instrument used by the Greeks and Romans for measuring time by the trickling of water.
The Greeks called the water-clock a clepsydra, which means "the water steals away."
In the clepsydra (Fig. 1) the descent of the weight was controlled by the size of the stream of flowing water.