[52] O. Volger, Unters üb. d. Phän. d. Erdb. vol. iii. p. 414.

[53] Meteorologia Endogena, vol. i. p. 166.

[54] Gent. Mag. vol. xxvi. p. 91.

[55] Compte Rendu, 1873, p. 66.

[56] An Historical Account of Earthquakes, p. 46.

[57] Phil. Trans. vol. xlix. p. 436.

[58] Am. Jour. Sci. vol. xlv. p. 129.

[59] Phil. Trans. vol. xlix. p. 547.

[60] Ibid. vols. xlii. and xxxix.

[61] Phil. Trans. vol. xlix, part i.