INDEX. 



489 



canoes upheaved on fissures, 

 265. See Volcanoes. 



Fitzroy's magnetic observations, 

 71. 



Floods in rivers, prognostication 

 of, 187. 



Forbes, on the conductive power 

 of different rocks, 38. 



Fogo, volcano of the Ilha do, 

 262. 



Formosa, the turning-point of the 

 lines of volcanic elevation in 

 the islands of Eastern Asia, 369 ; 

 its volcanoes, 377. 



Foucault's apparatus for demons- 

 trating the rotation of the 

 earth, 25. 



France, extinct volcanoes of, 238, 

 278. 



Franklin on frozen earth in the 

 north-west of America, 48 ; his 

 Arctic voyages, 65 ; search for 

 him, 65. 



Franklin's Bay, volcano of, 

 more properly a salse, 419. 



Fredonia, near Lake Erie, springs 

 of inflammable gas at, 213. 



Fremont's hypsometrical investiga- 

 tions in North- West America, 

 410. 



Fremont's Peak, 415. 



French Alps, highest summit of 

 the, 230. 



Frozen earth, its geographical ex- 

 tension, 46. 



Fse-nan, a Chinese magnetic appa- 

 ratus, 50. 



Fuego, Volcan de, described, 276. 



Fumaroles, various classes of, 424; 

 Bunsen on their products, 424. 



Fummarole of the Tuscan Ma- 

 remma, 211. 



Fused interior of the earth, 246. 



Galapagos, the, countless cones 



and extinct craters, 400 ; pumice 



not found there, 401. 

 Gal era Zamba, terrible eruptions 



of flames and terrestrial changes 



at, 218. 



Gandavo, Fray Juan de, explores 

 the crater of Masaya, 260. 



Gas, volcanic exhalations of, in- 

 quiry into, 441. See also 

 Springs. 



Gauss, his theory of terrestrial 

 magnetism, 62. 



Gay Lussaconthe chemical causes 

 of volcanic phenomena, 169 ; 

 on waves of commotion and 

 oscillation, 171. 



Gemellaro, his estimate of the 

 height to which erupted bodies 

 ascend from Etna, 265. 



Geographical distribution of vol- 

 canoes, 421 ; an abnormal phe- 

 nomenon in, noticed, 433. 



Geological terms, origin of some, 

 450. 



Geysirs, the, of Iceland described, 

 199. 



Gilbert, William, lays down com- 

 prehensive views on the mag- 

 netic force of the earth, 57. 



Glassy felspar. See Felspar. 



Godivel, Lac de la, an extinct 

 volcano, 238. 



Gog and Magog, oriental myth of, 

 359. 



Gold, believed to be found in 

 volcanoes, 261 ; descent into 

 Masaya in search of it, 261. 



Graham, his observation of the 

 hourly variations of the mag- 

 netic force, 60. 



Graham Island, temporary for- 

 mation of, 349. 



Grand Ocean, a term for the basin 

 of the South Sea, objected to, 

 404. 



Granite,Mitscherlich's experiments 

 on the melting point of, 246. 



Greece, has frequently suffered 

 from earthquakes, 177; great 

 number of thermal springs, 177. 



Grenelle, the Artesian well of, 36. 



Ground temperature, observations 

 on, 1 90. See also Frozen earth. 



Guadeloupe, the Soufriere of, de- 

 scribed, 423. 



