366 COSMOS. 



— Mouna Loa, with Kilauea on its eastern declivity; the 

 cone mountain of Tanna, in the New Hebrides ; and Assump- 

 tion Island in the North Ladrones), would afford us no in- 

 formation in regard to the general formation of volcanoes in 

 the basin of the South Sea. The case is quite different if 

 we limit ourselves to single groups of islands, and look back 

 to remote, perhaps pre-historic, epochs when the numerous 

 linearly-arranged, though now extinct, craters of the Ladrones 

 (Marian Islands), the New Hebrides, and the Solomon's Isl- 

 ands were active, but which certainly did not become gradu- 

 ally extinguished in a direction either from southeast to north- 

 west or from north to south. Though I here name only vol- 

 canic island chains of the high seas, yet the Aleutes and oth- 

 er true coastian islands are analogous to them. General con- 

 clusions as to the direction of a cooling process are deceptive, 

 as the state of the conducting medium must operate tempo- 

 rarily upon it, according as it is open or interrupted. 



Mouna Loa, ascertained by the exact measurement* of the 

 American exploring expedition under Captain "Wilkes to be 

 13,758 feet in height, and consequently 1600 feet higher than 

 the Peak of Teneriffe, is the largest volcano of the South Sea 

 Islands, and the only one that still remains really active in 

 the whole volcanic Archipelago of the Hawaii or Sandwich 

 Islands. The summit craters, the largest of which is nearly 

 13,000 feet in diameter, exhibit ifi their ordinary state a solid 

 bottom, composed of hardened lava and scoriae, out of which 

 rise small cones of eruption, exhaling vapor. The summit 

 openings are, on the whole, not very active, though in June, 

 1832, and in January, 1843, they emitted eruptions of sever- 

 al weeks' duration, and even streams of lava of from 20 to 28 

 geographical miles in length, extending to the foot of Mouna 

 Kea. The fall (inclination) of the perfectly connected flow- 

 ing stream! was chiefly 6°, frequently 10°, 15°, and even 25°. 

 The conformation of the Mouna Loa is very remarkable, from 

 the circumstance of its having no cone of ashes, like the Peak 

 of Teneriffe, Cotopaxi, and so many other volcanoes ; it is 

 likewise almost entirely deficient in. pumice, { though the 



* See Cosmos, vol. v., p. 238, note J. 



t Dana, Geology of the United States Explor. Exped., p. 208 and 210. 



X Dana, p. 193 and 201. The absence of cinder-cones is likewise 

 very remarkable in those volcanoes of the Eifel which emit streams of 

 lava. Reliable information, however, received by the missionary Dib- 

 ble from the mouths of eye-witnesses, proves that an eruption of ashes 

 may notwithstanding occur from the summit crater of Mouna Loa, for 

 he was told that, during the war carried on by Kamehameha against 



