Abstract

A tripartite sundial from Tell Er Ras, Zeus Temple, Mt Gerizim, (by R. J. Bull, Drew University, USA). Bull: The sundial, formed from a block of local limestone 440 mm long, 300 mm wide and 325 mm high, has suffered damage, especially to its top and back. As a result, most of its dimensions and many of its details have been determined. At the back of the limestone block two spaces, each in the shape of a quarter-sphere, one at either end of the block, have been hollowed out of the stone. This triple sundial probably functioned in the following manner: If the limestone block was positioned so that Sundial 3 was oriented to the east and Sundial 2 to the west, Sundial 1 would face north. The rising sun would cause two shadows to be cast, one by the gnomon on the face of Sundial 1, the other by the gnomon of Sundial 3. Both shadows would move from the first hour, A, progressively through the six hours of the morning until the sixth hour, noon, vertical shadows would lie along the lines marked by the numeral F. Observer A facing south and looking at the north face of Sundial 1 would in the course of the morning hours see the gnomon shadow progress from its right to its left, while at the same time Observer B facing north and looking at Sundial 3 would see the gnomon shadow progress in the course of the morning hours, from left to right. As the afternoon progressed the shadow on the dial of Sundial 1 would continue to progress from right to left through the last hour of the day. At the same time Sundial 3 would increasingly fall into shadow whereas from the hour of noon, the gnomon shadow on Sundial 2 would begin to mark the afternoon hours moving from left to right as viewed by Observer B.