The most interesting discovery at Olympia was that of the actual lines which marked the start and finish of the races (Fig. 41). These lines consist of stone sills about 18 inches wide extending nearly the whole breadth of the course. Each sill is divided at intervals of about 4 feet by square sockets obviously intended to hold posts. Between each pair of sockets are two parallel grooves cut in stone about 7 inches apart. Their object was clearly to mark the place for the runners’ feet. There are twenty of these sections in the western sill and twenty-one in the eastern sill, one of which is, however, a short one. Each section afforded room for a single runner. The western sill is 11 metres from the end of the stadium, the eastern only 9-1/2. The distance between the two sills is 192·27 metres, which gives ·32045 as the length of the Olympic foot. The Olympic foot was said to have been determined by Heracles, who measured out the stadium with his own feet. Hence the stadium at Olympia is slightly longer than other stadia on the mainland.[437] The discovery of similar stone sills in the gymnasium at Olympia, and subsequently at Delphi and Epidaurus, makes it probable that they were universally employed in Greek stadia, though it is impossible definitely to fix the date at which they replaced the earlier custom of marking the lines in the sand. The reason why the lines are alike at either end is obvious. In the stade-race the finish was at the opposite end from the start, in the diaulos and other races consisting of an even number of stades the runners finished where they started. Hence, as it was clearly desirable that all races should finish at the same point, it was necessary to have starting lines at both ends. At Olympia it seems probable that the finish was at the eastern end of the course. Here were the seats of the Hellanodicae, and opposite them was the seat of the priestess of Demeter Chamyne, the only married woman, possibly the only woman, who was allowed to be a spectator at the Olympia.