TRUE VOLCANOES. 391 



gradually extinguished in a direction either from south- 

 east to north-west or from north to south. Though I 

 here name only volcanic island-chains of the high seas, yet 

 the Aleutes and other true coastian islands are analogous 

 to them. General conclusions as to the direction of a cool- 

 ing process are deceptive, as the state of the conducting 

 medium must operate temporarily upon it, according as it is 

 open or interrupted. 



Mouna Loa, ascertained by the exact measurement 8 ' 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 in 

 their ordinary state a solid bottom, composed of hardened 

 lava and scoriae, out of which rise small cones of eruption, 

 exhaling vapour. The summit openings are on the whole 

 not very active, though in June 1832 and in January 

 1843, they emitted eruptions of several weeks' duration, and 

 even streams of lava of from 20 to 28 geographical miles in 

 length, extending to the foot of Monna Kea. The fall (in- 

 clination) of the perfectly connected flowing stream 86 was 

 chiefly 6 U , frequently 10, 15, and even 25. The conforma- 

 tion of the Mouna Loa is very remarkable from the circum- 

 stance 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 87 though the 

 blackish-grey, and more trachy tic than basaltic, lavas of the 



85 See Cosmos, vol. v, p. 250, note 35. 



so Dana, Geology of the U. St. Explor. Exped., pp. 208 and 210. 



87 Dana, pp. 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 

 the insurgents in the year 1789, an eruption of hot ashes, accompanied 

 by an earthquake, enveloped the surrounding country in the darkness 

 of night (p. 183). On the volcanic glass threads (the hair of the god- 

 dess Pele, who before she went to settle at Hawaii inhabited the now 



