He built a horologium at Athens, the so-called Tower of the Winds, a considerable portion of which still exists. It is octagonal, with figures carved on each side, representing the eight principal winds. In antiquity a bronze figure of Triton on the summit, with a rod in his hand, turned round by the wind, pointed to the quarter from which it blew. From this model is derived the custom of placing weathercocks on steeples.