284 Condition of Vesuvius, 



width was from four to five feet. From the form of the surface of 

 the surrounding lava, I concluded that, not long since, its place of exit 

 was higher up, and that by the solidification of its surface, the change 

 had been produced in the situation of its source, a process which now 

 appears to be going on — we approached it within four feet. I can- 

 not say that I felt disposed to try the experiment which DoJomieu 

 states to be safe, that is, to walk over it, the heat of the surface, as 

 he says, not being sufficient to burn. It is certain, that the reflected 

 heat was sufficient to induce me to preserve the distance abovemen- 

 tioned. With one of our rough canes, we took some of the red hot 

 viscid fluid from the stream and into it pressed some coins. I have 

 one specimen, impressed on one side with the name of our cicerone 

 Sahatore Madonna, and on the other, the time and the year when 

 thus enstamped. The lava cools rapidly, hardening into a black sco- 

 riaceous vesicular mass, without the usual crystals of leucite, horn- 

 blende, or pyroxene. May not this absence of crystals, be owing to 

 the fact that they were taken from the surface, where these minerals 

 not under pressure, are decomposed by the heat? The same is the 

 nature of the solidified lava which covers this part of the old crater. 

 This stream is the only present outlet for the lava of the volcano. 

 The crater is not in sufficient action to force it over its sides. 



There yet remained to be seen the interior of this crater. Our 

 guides spoke to us of the danger, and perhaps more from disliking 

 the trouble of ascending than from fear, at first refused to accompany 

 us. It was not usual to climb it on this the eastern side ; but there 

 was no other alternative ; for the opposite side, where was the beat- 

 en track, was rendered impassable by the thick volumes of suffocat- 

 ing smoke. They at last consented, as we had determined on going. 

 Its elevation is two hundred and fifty feet, the whole of which has 

 been formed within the past five years ; in 1830 there was but a 

 small mound. Its elevation is owing to the cinders and small pieces 

 of lava, with perhaps occasionally a current, which are thrown out 

 and fall down its sides. Its sides inchne at an angle of 40°, as great 

 an inclination, considering the manner in which they are formed, as 

 they could have. When making the ascent, I perceived very sensi- 

 bly, a tremulous motion, and when on the summit I observed that 

 this trembling took place at each of its slight eruptions. There 

 were no subterranean sounds. The eruptions were of heated cind- 

 ers, melted lava and" sulphur, v/hich were darted to the height of 

 twenty or thirty feet in the air, every four or five minutes. The 



