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The invention of the sand clock |
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| Authors: | RT Balmer |
| Abstract: | The simple draining liquid clepsydra (water clock) was in use in Egypt by 1500 B.C. The replacement of the liquid with a fine granulated material, thus converting the clepsydra into a clepsammia (sand clock), appears not to have occurred before the mediaeval period. What human need was then met by the sand clock that could not be met by a water clock or early mechanical clock? |
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