WINTER VISIT TO GLACIERS. 317 



In the following winter, or, rather, in the 

 early days of March, 1841, Agassiz visited, 

 in company with M. Desor, the glacier of 

 the Aar and that of Rosenlaui. He wished 

 to examine the stakes planted the summer 

 before on the glacier of the Aar, and to 

 compare the winter and summer temperature 

 within as well as without the mass of ice. 

 But his chief object was to ascertain whether 

 water still flowed from beneath the glaciers 

 during the frosts of winter. This fact would 

 have a direct bearing upon the theory which 

 referred the melting and movement of the 

 glaciers chiefly to their lower surface, explain- 

 ing them by the central heat of the earth as 

 their main cause. Satisfied as he was of the 

 fallacy of this notion, Agassiz still wished to 

 have the evidence of the glacier itself. The 

 journey was, of course, a difficult one at such 

 a season, but the weather was beautiful, and 

 they accomplished it in safety, though not 

 without much suffering. They found no 

 water except the pure and limpid water from 

 springs that never freeze. The glacier lay 

 dead in the grasp of winter. The results of 

 this journey, tables of temperature, etc., are 

 recorded in the " Systeme Glaeiaire." 



In E. Desor's " S^ jours dans les Glaciers " 



