Note 44 — INTRODUCTION

The gnomon was not a sundial, but an upright erected on a flat surface, in the centre of three concentric circles. These were drawn so that the end of the gnomon’s shadow touched the innermost circle at midday on the summer solstice, the intermediate circle at the equinoxes, and the outermost circle at the winter solstice. See Bretschneider, Die Geometrie vor Euklid, p. 60.