CHAP. 74. (72.)—REMARKS ON DIALS, AS CONNECTED WITH THIS SUBJECT.
The same dial-plates[505] cannot be used in all places, the shadow of the sun being sensibly different at distances of 300, or at most of 500 stadia[506]. Hence the shadow of the dial-pin, which is termed the gnomon, at noon and at the summer solstice, in Egypt, is a little more than half the length of the gnomon itself. At the city of Rome it is only 1⁄9 less than the gnomon, at Ancona not more than 1⁄35 less, while in the part of Italy which is called Venetia, at the same hour, the shadow is equal to the length of the gnomon[507].