[418] Tyndall, On Cometary Theory, Philosophical Magazine, April 1869. 4th Series, vol. xxxvii. p. 243.
[419] See Philosophical Transactions, abridged by Lowthorp. 4th edit. vol. i. p. 130. I find that opinions similar to those in the text have been briefly expressed by De Morgan in his remarkable preface to From Matter to Spirit, by C.D., pp. xxi. xxii.
[420] Horrocks, Opera Posthuma (1673), p. 276.
[421] Young’s Works, vol. i. p. 593.
[422] Boyle’s Physical Examen, p. 84.
[423] Young’s Works, vol. i. p. 415.
[424] Familiar Lectures on Scientific Subjects, p. 282.
[425] Young’s Works, vol. i. p. 417.
[426] Principia, bk. iii. Prop. 43. General Scholium.
[427] Ibid. bk. ii. Sect. ix. Prop. 53.