354 LOUIS AGASSIZ. 



crack opened between my feet and ran rap- 

 idly across the glacier in a straight line." 1 

 On this occasion Agassiz saw three crevasses 

 formed in an hour and a half, and heard oth- 

 ers opening at a greater distance from him. 

 He counted eight new fissures in a spaco of 

 one hundred and twenty-five feet. The phe- 

 nomenon continued throughout the evening, 

 and recurred, though with less frequency, dur- 

 ing the night. The cracks were narrow, the 

 largest an inch and a half in width, and their 

 great depth was proved by the rapidity with 

 which they drained any standing water in 

 their immediate vicinity. " A boring-hole," 

 says Agassiz, " one hundred and thirty feet 

 deep and six inches in diameter, full of water, 

 was completely emptied in a few minutes, 

 showing that these narrow cracks penetrated 

 to great depths." 



The summer's work included observations 

 also on 'the comparative movement of the gla- 

 cier during the day and night, on the surface 

 waste of the mass, its reparation, on the neve* 

 and snow of the upper regions, on the merid- 

 ian holes, the sun-dials of the glaciers, as they 



1 Extract from a letter of Louis Agassiz to M. Arago dated 

 from the Hotel des Neuchatelois, Glacier of the Aar, August 

 7, 1842. 



