NOTES. CXX111 



Bischofs remarkable experiments in casting a ball of basalt, that substance 

 appeared, according to some hypothetical assumptions, to require a temperature 

 of 165 Re'aumur higher than the melting point of copper. (Warmelehre des 

 Innern unsers Erdkorpers, S. 473.) 



( 465 ) p. 326. Kosmos, Bd. iv. S. 218 (English edition, p. 169). Com- 

 pare also, respecting the unequal extension and depth of the icy soil, apart from 

 latitude, the remarkable observations of Franklin, Erman, Kupffer, and, above 

 all, Middendorff. Kosmos, Bd. iv. S. 43, 47, and 167 (English edition, p. 

 4248, and Note 46). 



( 466 ) p. 326. Leibnitz, in the Protogsea, 4. 



( 467 ) p. 327. On Vivarais and Velay, see the most recent and very exact 

 researches of Girard, in his " Geologischen Wanderungen," Bd. i. (1856) S. 161, 

 173, and 214. The ancient volcanoes of Olot were discovered by the American 

 geologist Maclure in 1808, visited by Lyell in 1830, and well described and re- 

 presented by him in his Manual of Geology, 1855, p. 535 542. 



( 46S ) p. 328. Sir Kod. Murchison, Siluria, p. 20 and 55-58 (Lyell, Ma- 

 nual, p. 563). 



( 469 ) p. 328. Scoresby, Account of the Arctic Regions, vol. i. p. 155 169, 

 Tab. V. and VI. 



( 47 ) p. 329. Le'op. von Buch, Descr. des lies Canaries, p. 357369; and 

 Landgrebe, Naturgeschichte der Vulkane, 1855, Bd. i. S. 121 136; and on 

 the encircling ridges of the elevation-craters (caldeiras) in the islands of San 

 Miguel, Fayal, and Terceira (according to the charts of Vidal), see Kosmos, 

 Bd. iv. Anm. 84 zu S. 271 (English edition, Note 308). The eruptions of 

 Fayal (1672) and S. Jorge (1580 and 1808) appear to depend on the prin- 

 cipal volcano, that of Pico. 



( 471 ) p. 329. Kosmos, Bd. iv. S. 291 (Anm. 27) and 301 (English edition, 

 257). 



( 472 ) p. 329. Results of Observations on Madeira, by Sir Charles Lyell and 

 Hartung, in the Manual of Geology, 1855, p. 515 525. 



( 47S ) p. 330. Darwin, Volcanic Islands, 1844, p. 23 ; and Lieut. Lee, 

 Cruise of the U.S. Brig Dolphin, 1854, p. 80. 



( 474 ) p. 330. See the excellent description of Ascension by Darwin, Volcanic 

 Islands, p. 40 and 41. 



( 475 ) p. 330. Darwin, p. 84 and 92, on " the great hollow space or valley 

 southward of the central curved ridge, across which the half of the crater must 

 once have extended. It is interesting to trace the steps, by which the structure 

 of a volcanic district becomes obscured, and finally obliterated. (Compare also 

 Seale, Geognosy of the Island of St. Helena, p. 28.) 



