Clepsydra of the Oropos Amphiareion

Excavated by the Archaeological Society in Athens in 1884, the clepsydra (water clock) at the Amphiareion at Oropos is thought to have been built in the 4th century BCE. This particular clepsydra is a rare example of an inflow water clock, meaning time is measured against a constant rate of deposition, rather than the more usual outflow water clocks found in ancient Greece. The clock is located opposite the sacred spring at the Amphiareion, to the southeast of the sanctuary. It is made up of a rectangular tank with a staircase leading down, allowing for an attendant to routinely pull a plug and drain the tank of water. A pipe sourced from the nearby sacred spring was likely used to fill the tank with water. This particular water clock is unusually well-preserved, allowing for a better study of its mechanics and ancient water clocks in general.