clepsydra

Greek compound term universally used for a water clock and which derives from the words klepto (κλέπτω), i.e. ‘to steal', and hydor (ὕδωρ), i.e. ‘water', and refers to any timepiece used to measure time by a regulated flow of liquid into or out from a vessel. In the past, the drum tower in China was used to broadcast the local time. To calculate the time for themselves, as to know when to hit the drums, the overseer of the drum tower supposedly made use a giant clepsydra, in which water trickled down from the taps of a series of vessels, positioned in sequence at different elevations, with at the base a cylindrical vessel with a measuring rod that would rise with the water level and indicated the time. On the side it has a bronze, mechanical, mandarin-like figurine holding a set of cymbals, that would be activated by an overflow mechanism every 15 minutes and clap the cymbals (fig.). This system, with a principle reminiscent to that of a lock, was itself synchronized with a backup system of spiral-shaped incense coils, that were grooved at intervals, allowing for the time to be measured while burning. Inside the medieval Elephant Clock, i.e. a water clock in the form of an Asian Elephant with a howdah on its back and invented by the Muslim engineer Al-Jazari (1136–1206 AD), sat a clepsydra connected to a bar which triggered a mechanism releasing a heavy ball that rolled down the inside or belly of a naga or dragon-like creature, that would tilt when the balance shifted, thus setting in motion a time indicating mechanism in the form of a bird perched on the top of the howdah, while simultaneously dropping the ball in a container, thus making the mahout seated on the elephant's neck beat a drum. In Burma, present-day Myanmar, gold beaters, i.e. artisanal producers of gold leaf (fig.), up to present make use of a coconut clepsydra to measure the passage of time while beating gold (fig.). See also sundial. 回