242 Professor Agassiz on the Glacier Theort/, 



which it carries off from the bed of mud or of gravel that is 

 interposed between the glacier and the rock. If it be really 

 glacier-water which escapes from glaciers in winter, that wa- 

 ter ought to possess these qualities ; whereas, if it be spring- 

 water, it ought to be clear and limpid, from wher« it begins 

 to run. 



It was of importance that I should myself examine on the 

 spot the value of his reasoning ; and it was with this view 

 tliat I visited, in company with M. Desor, the glaciers of the 

 Bernese Oberland, at the beginning of the month of March 

 last year (1841), a period when winter reigns supreme in 

 tlie High Alps. We selected the glaciers of the Aar and 

 of Rosenlaui as the field of our observations, and proceeded 

 towards the Hospice of the Grimsel, by ascending the fine 

 valley of Hassli, which was still entirely covered with snow. 

 The Aar, above Meyringen, was reduced to a small stream, 

 the water of which was much clearer than in summer, — a cir- 

 cumstance which led us to suppose that it was chiefly, if not 

 entirely, composed of spring- water. Bridges of ice traversed 

 the bed of the river at a multitude of places, and as they were 

 very thick, we were able to cross them in perfect safety. 

 Above the height of 4000 feet, there only remained but a very 

 small thread of water. The snow had frequently a thickness 

 of 10 feet ; the great and beautiful cascade of the Handeck 

 had disappeared ; and, on examining the beds of gneiss form- 

 ing the precipice over which the water is precipitated in 

 summer, we saw with astonishment, that they had partially 

 preserved their projecting' angles, and were not at all worn, 

 as we should have supposed they must have been, especially 

 when we remember that the Aar transports an enormous quan- 

 tity of gravel. I insist on this fact, because it proves that if 

 the water which has struck with violence against these rocks 

 for a long series of ages, has not succeeded in rounding them, 

 it is impossible, to understand how we can attribute to the ac- 

 tion of water the polish and the rounded form of the flanks of 

 this same valley, at places where the inclination is much less 

 considerable, and the valley much less contracted, and whore 

 the current must have acted with a proportionably much small- 

 er degree of violence. It may perhaps be objected that these 



