EXHIBITS > The clocks of the ancient Greeks >
The hydraulic clock of Κtesibios
(an automation miracle, continuously working without human interference)
It was a marvel of automation, since the clock was able to operate continuously, without human intervention, indicating the 365 different hours of the year. The water from a spring supplied, through a spillway, the upper bronze container. This, in turn, supplied the smaller intermediate container which was a constant level controller through a system it contained (a conical valve on the float to interrupt the flow). Then a dripper supplied the tall bronze container, drop by drop, with a constant water supply. With the rising of water in it, the float rose and, through a shaft, a statuette with a pointer rose at the same pace. The pointer indicated the hour of 24 on a rotating drum containing a trace of hours of day and night depending on the date. At the end of the 24 hours, the water exceeded the side-built siphon and drained rapidly. On the descent of the float an ingenius drive system was activated in the ratio of 1 in 365 (which consisted of a toothed rule, a pawl, two gears and a worm gear) that ensured the rotation of the drum calibrated in 1/365 of its circumference as the pointer of the statuette now indicated the exact time of the next day.