324 LOUIS AGASSIZ. 



to a depth of eighty feet, and even beyond, 

 though with less distinctness. 



The summer closed with their famous as- 

 cent of the Jungfrau. The party consisted 

 of twelve persons : Agassiz, Desor, Forbes, 

 Heath, and two travelers who had begged to 

 join them, M. de Chatelier, of Nantes, and 

 M. de Pury, of Neuchatel, a former pupil of 

 Agassiz. The other six were guides ; four 

 beside their old and tried friends, Jacob Leu- 

 thold and Johann Wahren. They left the hos- 

 pice of the Grimsel on the 27th of August, 

 at four o'clock in the morning. Crossing the 

 Col of the Oberaar they descended to the 

 snowy plateau which feeds the Viescher gla- 

 cier. In this grand amphitheatre, walled in 

 by the peaks of the Viescherhorner, they 

 rested for their midday meal. In crossing 

 these fields of snow, while walking with per- 

 fect security upon what seemed a solid mass, 

 they observed certain window-like openings in 

 the snow. Stooping to examine one of them, 

 they looked into an immense open space, 

 filled with soft blue light. They were, in fact, 

 walking on a hollow crust, and the small win- 

 dow was, as they afterward found, opposite a 

 large crevasse on the other side of this ice- 

 cavern, through which the light entered, flood- 



