It is the nickname of a famous harlot in the ancient Greece, called Metike. To avoid that customers are much procrastinating in the preliminaries, putting them a 'clock' which was a copper bowl full of water hanging chains. In floating a hollow ball of iron which had a few small holes. Water slowly went through the holes and when the field was filled, ended up falling down, hitting the base as if it were a gong. If the customer had not yet finished, I had to pay another turn. When they discovered Metike trucaba timer by enlarging the holes of the sphere to make it fall before, began to call "Klepsydra" (literally "water thief"), as well as their watches. Today is called clepsidra also the hourglasses and all who transferred a fluid from one container to another.