Note 182 — Chapter VII

This follows, observes Herschel, from a very simple theorem, which may be thus stated:—"The amount of heat received by the earth from the sun, while describing any part of its orbit, is proportional to the angle described round the sun's centre." So that if the orbit be divided into two portions by a line drawn in any direction through the sun's centre, the heat received in describing the two unequal segments of the eclipse so produced will be equal. Geol. Trans. vol. iii. part. ii. p. 298; second series.