A HISTORY OF SCIENCE 



of valleys in places where it is not possible to suppose 

 that water has ever formed a current. Some geolo- 

 gists, in their embarrassment to explain these phenom- 

 ena, have supposed that they were due to the infiltra- 

 tion of acidulated water, but this hypothesis is purely 

 gratuitous. 



"We will now describe the remains of these various 

 phenomena as they are found in the Alps outside the 

 actual glacial limits, in order to prove that at a certain 

 epoch glaciers were much larger than they are to-day. 



"The ancient moraines, situated as they are at a 

 great distance from those of the present day, are no- 

 where so distinct or so frequent as in Valais, where 

 MM. Venetz and J. de Charpentier noticed them for 

 the first time ; but as their observations are as yet un- 

 published, and they themselves gave me the informa- 

 tion, it would be an appropriation of their discovery 

 if I were to describe them here in detail. I will limit 

 myself to say that there can be found traces, more or 

 less distinct, of ancient terminal moraines in the form 

 of vaulted dikes at the foot of every glacier, at a dis- 

 tance of a few minutes' walk, a quarter of an hour, a 

 half -hour, an hour, and even of several leagues from 

 their present extremities. These traces become less 

 distinct in proportion to their distance from the glacier, 

 and, since they are also often traversed by torrents, 

 they are not as continuous as the moraines which are 

 nearer to the glaciers. The farther these ancient 

 moraines are removed from the termination of a glacier, 

 the higher up they reach upon the sides of the valley, 

 which proves to us that the thickness of the glacier 

 must have been greater when its size was larger. At 



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