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Opticks, 3rd edit. p. 159.

Watts, Dictionary of Chemistry, vol. iii. p. 637.

Faraday’s Life, by Bence Jones, vol. ii. p. 5.

Preliminary Discourse, &c., p. 185.

Philosophical Magazine, July, 1857, 4th Series, vol. xiv. p. 24.

First Principles, 3rd edit. chap. x. p. 253.

Laplace, System of the World, vol. i. pp. 50, 54, &c.

Herschel’s Outlines of Astronomy, 4th edit. pp. 555–557.

Humboldt’s Cosmos (Bohn), vol. iii. p. 229.

Encyclopædia Metropolitana, art. Sound, § 323; Outlines of Astronomy, 4th edit., § 650. pp. 410, 487–88; Meteorology, Encyclopædia Britannica, Reprint, p. 197.

Philosophical Transactions, (1739), vol. xli. p. 126.

Principia, bk. iii. Prop. 15.

Lockyer’s Lessons in Elementary Astronomy, p. 301.

Treatise on Natural Philosophy, vol. i. pp. 337, &c.