The “anaphoric” clock

The “anaphoric” clock is held by Kotsanas Museum of Ancient Greek Technology. Museum description: It was a brilliant hydraulic clock which indicated, with accuracy, the 365 different hours of the year.

A cam disc - on which a drawing represented the sky and the zodiac cycle – rotated behind a bronze grid. The grid consisted of 7 homocentric circles defining the month intervals and 24 curved rods defining the hours according to the “hour – month” diagram (“analemma”). The rotation of the disc was achieved through a pulley and a flexible chain with a counterweight and a weight-float which was lowered or lifted through the isochronous (=equal time) descent or ascent of the water level.

This isochronous descent or ascent was ensured by the isochronous water outflow through a self-regulated controller of the constant level of the Ktesibios type. Every day a pointer was placed successively on the corresponding one of the 365 holes of the disc periphery, which defined the days of the zodiac The museum record gives place associated: Ancient Greece; maker recorded: Kostas Kotsanas. These details come from the holding museum's own record; how far this object represents a wider collectible type has not yet been independently verified.