Gharpeiiticrs Esmy on Glaciers, lOi 



of glaciers are still matter of controversy, and the great influ- 

 ence which it is now thought may be ascribed to them in all 

 that relates to the dispersion and transportation of erratic 

 blocks, gives a new interest to the examination of all the facts 

 connected with them. 



According to M. de Charpentier, it never snows in flakes on 

 high mountains, on account of the dryness of the air ; but the 

 vapours condense in such situations in transparent rounded 

 grains, similar to those we call hoar-frost. It is this which 

 constitutes the upper nev« of the Alps, and which is trans- 

 formed into glacier at its lower portion. The snows of the 

 equatorial Cordilleras are all neves, and their coherence Is 

 so slight, that they resemble a mass of ashes, which the wind 

 carries off in whirls. 



In order to account for the conversion of the neve into gla- 

 cial ice, M. de Chai-pentier maintains the same theory admitted 

 by Agassiz, that is, the absorption and congelation of the rain- 

 water, or that which proceeds from the melting of the neve, 

 uniting and cementing the grains. This absorption of water 

 takes place unequally according to the height, inclination, the 

 vicinity of crevices, &c. It is during the day, in summer, that 

 the inhibition of water takes place, and it is during the night 

 that such water becomes congealed. The expansion of the 

 ice formed, and the unequal distribution of the water in the 

 glacier, cause a tension which ruptures and splits the whole 

 mass of the glacier, and these capillary fissures extend in every 

 direction. M. Agassiz ascribes the fissures to the compression 

 of the bubbles of air enclosed in the ice, but M. de Charpen- 

 tier'^s explanation appears the most probable. These innume- 

 rable fissures render the glacier porous and permeable to the 

 water which the heat of the following day will produce, and 

 this alternate freezing and melting continue throughout the 

 summer. Thus we hear in glaciers during the night the 

 cracking noises produced by the rupture of the ice, sounds 

 sometimes so loud that they might be taken for the reports of 

 a cannon. 



M. de Charpentier does not admit that the ice of glaciers 

 is stratified, as M. Agassiz seems to believe ; he thinks that 

 stratification cannot appear but in the elevated n^v^s, whcird 



