1. The Greeks used the water clock, or clepsydra.

2. As a time - measuring apparatus , the clepsydra is used more widely than the sundial.

3. The invention and use sundial, clepsydra and other time - measuring machines is evidence of Chinese wisdom.

4. Water clock : or clepsydra , Ancient device for measuring time by the gradual flow of water.

5. Galileo used a mercury clepsydra to time his experimental falling Bodies.

6. Many ancient Chinese men of letters left behind beautiful verses about the clepsydra.

7. According to the record of ancient documents, this paper gives the possible structure of Li Lan's steelyard clepsydra, and demonstrates the principle for the stabilization of average flow velocity.