What I can see

The Klepsydra was a hydraulic clock. It is considered the “ancestor” of the clock of Kyrristos (Tower of the Winds/ Aerides) of the Hellenistic era. A similar clock, in better condition, exists in Amfiareio, an archeological site north of Athens.

What I can't see

The clock consists of a 2m. deep stone tank, which was filled with water through a pipe from the Klepsydra spring on the northern slope of the Acropolis. It was from this spring that the clock took its name. Likely beginning at sunrise each day, the water emptied slowly and steadily throughout the day through an outflow hole located at the bottom of the tank. Thus, as the level of the water decreased, the time that had passed was revealed. It was completely emptied after 17 hours. A century later, auxiliary tanks of different levels were installed, which did not empty the water, but instead filled the central tank. The word Klepsydra (Klevo + Ydor: I steal + water) is due to the fact that an underground natural pipeline “stole” water from the source of the Acropolis and ended up in the port of Faliro.

Bibliography