462 



INDEX. 



Tristan da Cunha, a volcanic island, 331. 

 Tshashtl Mountains, basaltic lavas of the, 



3S9. 

 Tucapel, volcano of, 273. 

 Tupnngato, measurement of the peak of, 



273. 

 Turbaco, the Volcancitos of, 204. 

 Tuscan Maremma, volcanic phenomena of 



the, 202. 

 Typhon, fable of, 253. 



Umnack, volcanic island of, 220. 



Unalavquen, volcano of, 274. 



Under currents of cold water in the tropics, 

 186. 



United States scientific expeditions, bene- 

 fits to natural history from the, 378. 



Uvillas or Uvinas, Volcan de, 271. 



Val del Bove, on -^tna, remarkable infer- 

 ence regarding, 215. 



Valleys of elevation, what, 193. 



Vancouver, Mount, 389. 



Vapor and gas springs, 212. 



Variation charts, their early date, 55. 



Vegetation, limit of, in Northern Asia, 45. 



Vesuvius, phenomena of an eruption of, as 

 observed by Humboldt, 174 ; barometri- 

 cal measurements by the same, 235; 

 lengthened series of eruptions of, 398; 

 described by Strabo, 398 ; by Dio Cassius, 

 399; by Diodorus Siculus, 400; by Vi- 

 truvius, 400 ; difference of constitution 

 of the old and the recent lavas, 444 ; en- 

 campment of Spartacus and his gladia- 

 tors on, 399. 



Vesuvius, valley furrows on the mantle of 

 the Somma of, 288. 



Vidua, Count Carlo, his melancholy death, 

 357. 



Vilcanoto, peak of, 279. 



Villarica, Volcan de, 274. 



Vincent, St., the volcano of, 394. 



Vincent of Beauvais, his mention of the 

 magnetic needle, 54. 



Virgenes, las, extinct volcanoes in Old Cal- 

 ifornia, 389. 



Vitruvius, notice of Vesuvius by, 400. 



Vivarais, extinct volcanoes of the, 263. 



Volcan Viejo, a crater in Southern Peru. 

 271. 



Volcancitos of Turbaco, described, 204. 



Volcanic districts, different aspects pre- 

 sented by, 214. 



Volcanic islands in the South Atlantic 

 Ocean, 332. 



Volcanic reaction, bands of, 170. 



Volcano, what intended imder the term, 

 by Humboldt, 272. 



Volcano, the island styled " the holy isle 

 of Hephsestos," 244. 



Volcanoes, considered according to the dif- 

 ference of their foi-mation and activity, 

 214; definite language of modern sci- 

 ence, 217 ; number of, on the earth, 393 ; 

 their great number in the Eastern Ar- 

 chipelago, 355 ; hypsometiy of, 235 ; lin- 

 ear arrangement of, 254 ; table of differ- 

 ences in structure and color of the mass 

 in certain, 432; the Mexican system, 

 264; sequence, latitude, and elevation, 

 26C ; particulars of the five groups of, in 

 the New Continent, 270; list of active, 

 263; geography of active, examined, 328; 

 geographical distribution of, 402; -open 

 in historical periods, list of, 330; semi- 

 volcanoes, 396. 



Volcanoes of the moon, 418. 



Vulcanicity, definition of, 158. 



Wales, volcanic phenomena in, 329. 



Walferdin on Artesian wells, 38. 



Waltershausen, his classification of the 

 volcanoes of Iceland, 330; his remarks 

 on the period of recurrence of eruptions 

 in various volcanoes, 243; on the tra- 

 chytes of -^i^tna, 433. 



Wilkes, Captain, commander of the Ameri- 

 can expedition, 102, 364. 



Wislizenus, positions in Northwest Ameri- 

 ca ascertained by, 381. 



Wisse, his observations of the eruptions of 

 the volcano of Sangai, 175, 251 ; his visit 

 to Pichincha, 231. 



Yana-Urcu, a volcanic hill, 1S5. 

 Yanteles (Yntales), volcano of, 274. 



Zapatera, extinct crater of the island, 



259. 

 Zohron, the southern pole of the magnetic 



needle, 54. 

 Zone of volcanic activity, 170. 

 Zuni, petrified forest near, 387. 



THE END. 



