THE CRUST OF THE EARTH. 



properly belongs, and of which all the products differ altogether 

 from the rocks of the semicircle called the Somma which existed 

 in ancient times, was not formed until a much more recent period, 

 and probably dates from the famous eruption of the year 76 A.D., 

 which was signalised by the loss of Pliny. It was then, probably, 



Fig. 54. Vesuvius as now formed. Fig. 55. Vesuvius in the time of Strabo. 



that a permanent communication was opened between the crater 

 and the internal parts of the earth. This catastrophe appears to 

 have produced but little lava, although it was attended with 

 violent effects on the surrounding country, throwing a great part 

 of the mountain into the sea, and burying Herculaneum and 

 Pompeii, not, as is vulgarly supposed, under molten matter 

 ejected from the crater, but under avalanches of pumiceous 

 substance, which existed previously upon the slopes of the 

 mountain. 



133. Of all existing volcanoes, that of Kirauea, in Hawaii, 

 one of the Sandwich Islands, better known under the popular 

 name of Owhyhee, and noted as the theatre of the murder of 

 Captain Cook, exhibits volcanic phenomena under their most 

 sublime and imposing aspect. The island of Hawaii, which is 

 about seventy miles long, and covers an area of 4000 square miles, 

 is a complete mass of volcanic matter, perforated by innumerable 

 craters. It is, in fact, a hollow cone, rising to an altitude of 

 16000 feet, having numerous vents over a vast incandescent mass, 

 which doubtless extends beneath the bed of the ocean, the island 

 forming a pyramidal funnel from the fluid nucleus beneath to the 

 atmosphere. The following graphic account of a visit to the 

 crater, by Mr. Ellis, affords a striking picture of the splendid, 

 but awful, spectacle which this volcano presents. 



" After travelling over extensive plains and climbing rugged 

 steeps, all bearing testimony of igneous origin, the crater of 

 Kirauea suddenly burst upon our view. We found ourselves 

 upon the edge of a steep precipice, with a vast plain before us 

 fifteen or sixteen miles in circumference, and sunk from two to 

 four hundred feet below its original level. The surface of this 

 plain was uneven, and strewed over with large stones and volcanic 

 rocks ; and in the centre of it was the great crater, at the distance 

 of a mile and a half from the precipice on which we were standing, 

 We proceeded to the northern end of the ridge, where, the sides 

 being less steep, a descent to the plain below seemed practicable ; 

 100 



