[168] Princ. Lib. I. prop. 60.
[169] Book I, Chap. 2. § 80.
[170] Princ. philos. Lib. I. prop. 58. coroll. 3.
[171] Newt. Optics. pag. 378.
[172] Newton. Princ. Lib. III. prop. 1.
[173] Newton, Princ. Lib. III. pag. 390,391. compared with pag. 393.
[174] Book I. Ch. 3. § 29.
[175] Princ. philos. Lib. I. prop. 4.
[176] Ibid. coroll.
[177] Newt. Princ. philos. Lib. III. pag. 390.