Note 61 — Chapter VI
Reading edition
On the causes of the temperature of Hot and Thermal Springs; and on the bearings of this subject as connected with the general question regarding the internal temperature of the Earth: by Professor Gustav Bischoff, of Bonn.—Edinburgh New Philosophical Journal, vol. xx. p. 376; vol. xxiii. p. 330. Some interesting information on the temperature of the ground will be found in Erman’s Travels in Siberia, translated by W. D. Cooley, vol. i. p. 339; vol. ii. p. 366. Sur la Profondeur à laquelle se trouve la couche de Température invariable entre les Tropiques, by Boussingault: Annales de Chimie et de Physique, 1833, p. 225. Reference may also be made to Humboldt’s Cosmos, Otto’s translation; and to the excellent article on Meteorology, by George Harvey, in the Encyclopædia Metropolitana. These chthonisothermal lines, as they are called, have been traced by Humboldt and others over extensive districts.