IXDEX. 



485 



principles of nature, 5 ; volcanic 

 phenomenon upon Hiera de- 

 scribed by, 229. 



Arran, volcanic phenomena in, 

 350. 



Artesian wells, Walferdin's obser- 

 vations on, 35. 



Ascension, volcanic phenomena of 

 the island of, 352. 



Asia, situation of the principal 

 volcanoes in, 297 ; volcanoes of 

 the western and central parts, 

 356 ; of Kamtschatka, 362 ; of 

 the islands of Eastern Asia, 367; 

 of the islands of Southern Asia, 

 377; of the Indian Ocean, 382. 



Atlantic Ocean, volcanoes of the 

 islands of the, 351; presumed 

 submarine volcano, 353. 



Atlantis of Solon, 179. 



Atolls, or lagoon reefs, 388. 



Attraction of the magnet known 

 to the Greeks and Romans, 50. 



Augite, 475. 



Aurora borealis, 152 ; observa- 

 tions of the black segment, 152; 

 colours observed in high lati- 

 tudes, 1 54 ; accompanying flee- 

 cy clouds, 155 ; influence on 

 terrestrial magnetism, 157; ob- 

 servations at Berlin and at Edin- 

 burgh, 158. 



Auvergne, extinct volcanoes of, 

 238, 278. 



Azores, craters of elevation in the, 

 227 ; the volcano Pico, 247. 



Azufral de Quindiu, Humboldt's 

 visit to the, 221 ; change of tem- 

 perature observed by Boussin- 

 gault, 221. 



Baily on the density of the earth, 

 31, 32. 



Baker, Mount, a volcano, 418. 



Banda, a volcanic island, 381. 



Barba, the volcano, described, 

 273. 



Barile, earthquake at, 173. 



Barrancos on the slopes of vol- 

 canoes, 304. 



Barren Island, one of the Anda- 

 mans, appearance of, as de- 

 scribed by Horsburgh, 383. 



Basalt-like columns of Pisoje, 456. 



Beaufort, Admiral, the Chimsera 

 described by, 257. 



Beauvais, Vincent of, on the mag- 

 netic needle, 53. 



Belcher, Sir E., magnetic observa- 

 tions by, 113. 



Bell-shaped volcanic mountains, 

 228. 



Berg, Albert, his description of 

 the burning spring, Chimsera, 

 257. 



Berlin, aurora observed at, by 

 Humboldt, 158. 



Bessel, determination of the size 

 and figure of the earth, 14, 27. 



Biot, pendulum measurements by, 

 23. 



Bolivia. See Peru. 



Borda, his services in equipping 

 the expedition of La Perouse, 

 61. 



Borneo, the Giava Maggiore of 

 Marco Polo, 379 ; doubtful 

 whether volcanoes exist there 

 379 ; great number of volcanoes 

 in its vicinity, 379. 



Bo-shan, eruption of the volcano, 

 437. 



Bouguer's experiments on the de- 

 viation of the plummet, 30 ; on 

 the pumice-quarries of Lactu- 

 cunga, 342. 



Boxirbon, volcanoes of the isle of, 

 383. 



Boussingault's method of deter- 

 mining the mean temperature, 

 40 ; on the cause of earthquakes, 

 170 ; on the matters ejected from 

 volcanoes, 335 ; on gases, 442. 



Bove, Val del, on Etna, 225, 241. 



Bramidos de Guanaxuato, 178. 



Bravais on Artesian wells, 37; on 

 the black segment of the Au- 

 rora, 153. 



Brisbane, Sir Thomas, his observa* 

 tory at Makerstoun, 123, 124. 



