LIBER II · CAPUT 72
REMARKS ON DIALS, AS CONNECTED WITH THIS SUBJECT
Latine · Mayhoff 1906
Vasaque horoscopa non ubique eadem sunt usui, in trecenis stadiis aut, ut longissime, in quingenis mutantibus semet umbris solis. itaque umbilici, quem gnomonem appellant, umbra in Aegypto meridiano tempore aequinoctii die paulo plus quam dimidiam gnomonis mensuram efficit, in urbe Roma nona pars gnomonis deest umbrae, in oppido Ancona superest quinta tricesima, in parte Italiae, quae Venetia appellatur, isdem horis umbra gnomoni par fit.
English · Bostock & Riley 1855–57
The same dial-plates cannot be used in all places, the shadow of the sun being sensibly different at distances of 300, or at most of 500 stadia. 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.