Charpentier^s Essay on Glaciers. 119 



diately preceded it. He entirely renounces the opinion he 

 had expressed in 1834, respecting a probable elevation of 

 the Alps very much above their present level, and he ascribeu 

 the change of climate to the numerous crevices and fissures 

 which the upward projection of the high Alps must have pro- 

 duced in the strata overturned by this formidable cataclysm. 

 All these crevices, the largest of which, filled in their lower 

 part, constitute at the present day the valleys of mountains, 

 must have served as passages for the waters, which were thus 

 enabled to penetrate to a great depth into the bosom of the 

 earth. Soon reduced to vapour by the heat of the beds over 

 which they ran, they became condensed in the atmosphere in 

 the form of rain or snow, and the temperature of the walls 

 of the crevices must in this way have rapidly diminished. 

 M. de Charpentier cites on this subject, on the authority of 

 M. Poeppig, the case of the volcano of Anduco, in Chili, from 

 which escape white vapours, which ai'e neither warm nor fe- 

 tid, but very humid, and which are seen to change into clouds 

 under the eyes of the observer. Thus, over a great extent of 

 the globe, a great quantity of vapours must have been disen- 

 gaged for a long period, and these, augmenting the humidity 

 of the atmosphere, and becoming transformed into fogs and 

 clouds, intercepted the rays of the sun, and in this way con- 

 tributed to diminish the temperature. In this way he esta- 

 blishes a long series of rainy and cold seasons, singularly fa- 

 vourable to the formation and development of glaciers, which 

 established themselves wherever the mountains were high 

 enough to permit, and particularly among the Alps. And it 

 is not necessary for this purpose to suppose an excessive de- 

 gree of cold. That of the years which succeeded each other 

 from 1812 to 1818 would be fully sufficient, according to M. 

 de Charpentier, supposing that it was continued for a long 

 enough time, to explain all the development hypothetically 

 attributed to the diluvial glaciers of the Alps. A very great 

 cold would be even contrary to the theory of glaciers, because 

 rain or liquid water is necessary for their formation and in- 

 crease. It is probable that this change of climate was the 

 cause of the gradual extinction of beings which had lived np 

 to that time ; they were enclosed among the ice formed at this 



