[48] In the place above-cited.

[49] These experiments are described in § 73.

[50] Book II. Chap. 5.

[51] Chap. 1. § 25, 26, 27, compared with § 15, &c.

[52] Book II. Chap. 5. § 3.

[53] See Euclid’s Elements, Book XII. prop. 13.

[54] Archimed. de æquipond. prop. 11.

[55] Ibid. prop. 12.

[56] Lucas Valerius De centr. gravit. solid. L. I. prop. 2.

[57] Idem L. II. prop. 2.