﻿196 



Prof. Milne — Visit to an active Volcano. 



old crater (B), whose sides at this point descended perpendicularly 

 I should think, at least 400 feet. Walking along this rim, which was 

 covered with large weather-worn whitish boulders, which looked not 

 unlike material which had been torn from the perpendicular faces 

 below us, we found a slope of ashes, down which we descended into 

 the bed of the old crater. On looking at the face of the perpendicular 



c r 



Approximate section of the upper portion of OsMma. 

 S — A, Outer slope of old crater-wall, (prehistoric ?) 

 B, Floor of old crater, partly filled hy later eruptions. 

 B — C, F — N, Outer slopes of modern crater-walls. 

 C,D,F, Eim of modern crater. 

 E, New volcanic cone formed by present eruption, January, 1877. 



cliffs from the top of which we had just descended, we saw they con- 

 sisted of irregularly broken and contorted bands of a whitish rock 

 like trachyte, more or less parallel. They were capped with beds of 

 ashes. In these ashes, as in the most scoriaceous portions of the 

 lava, crystals of a glassy felspar were very abundant. In the more 

 compact lava they were absent, that is, to the naked eye. The 

 rim of this old crater, although a serious obstacle on the side of our 

 ascent, is not continuous round the mountain, and is only to be seen 

 on the south and south-western side. 



After collecting a few specimens of rock from a black-looking 

 mass which was pi'obably the throat of an old vent, we pro- 

 ceeded forwards to make the ascent of another cone of ashes (B C), 

 which, from its position, was evidently that which remained of the 

 eruption succeeding the one which formed the crater we were then 

 leaving. The explosions we had heard when at a greater distance 

 were now more audible, and occurred rapidl}'^ in succession. As we 

 neared the top (C), which was about 800 feet above the plain from 

 which we started, the noise, which was liko that of immense jets 

 of steam, was sometimes accompanied with a tremulous motion of 

 the ground- It was not long before we reached the rim of the second, 

 crater (C), which we did to behold a sight defying my powers of 

 description. Instead of looking up at a crater, we were looking 

 down at one. Standing on the rim of crater C, before us there 

 was a short descent of loose, black ashes, somewhat steeper than 

 that up which we had climbed, terminating suddenly in perpendicular 

 cliffs, which formed an amphitheatre of rocks about half a mile in 

 breadth, the walls of which, upon the opposite side, were about 300 

 feet in height. At the bottom of this pit, on the side nearer to us, 

 a small cone, with an orifice of about 50 feet in diameter, was belch- 

 ing masses of molten lava to a height more than double that at 

 which we were standing. 



