230 Mr Edward Collomb on the 



pretty hard ; the foot sunk very little in it. Immediately 

 below, a layer of neve ice commenced, which became harder 

 and harder the farther one penetrated forwards into the mass. 

 By striking with the point of a hammer, morsels not larger 

 than the hand were displaced ; then by digging downwards, 

 it was ascertained, from the resistance offered, that this ice 

 became quite hard. 



" This snow was therefore stratified, as we have already 

 seen, in the month of April ; only the powdery snow of the 

 surface had disappeared, and then only remained successive 

 beds of 



*' Large granular neve ; 

 The ice of neve : 

 Vescicular ice ; 

 Compact ice. 

 The thickest part of these masses was still, in the month of 

 June, from 4 to 5 metres. 



" The passage of large granular neve into neve ice is easily 

 observed ; the transition is sudden. The neve is formed of 

 grains or granular concretions sometimes many millimetres 

 in diameter, translucent, brilliant, and moistened with water ; 

 they readily become agglutinated. The pressure, in the 

 hand, of the neve for a minute, is sufficient to convert it into 

 ice, — ^this neve ice being nothing else, as M. Charpentier has 

 already remarked, than the union or soldering together of a 

 certain number of these grains or concretions. 



" But the transition of the vescicular ice into compact ice 

 is not so easily discerned. These two species of ice pass in- 

 sensibly into one another. 



*' On the 15th of June, the temperature of the surrounding 

 air, at 2 o'clock p.m., on the eastern declivities of these moun- 

 tains, which do not rise above 1200 or 1300 metres above 

 the level of the sea, rose from 13 to 20 centigrade degrees in 

 a clear day. This temperature ought to have caused a rapid 

 melting, followed by a flow of water from the lower part of 

 these sloping patches of neve. On the day in question, how- 

 ever no water was discharged ; the neve, no doubt, disap- 

 peared, during fine weather, only by evaporation. The heat 

 of the ground does not assist in melting, for the layer of ice 



