Report of the Researches of M. Agassit, 167 



1840, and beginning of 1841, the periods of the publication of 

 the works of MM. Agassiz and Charpentier ; and shall, at the 

 same time, point out what were the problems which remained 

 to be solved when M. Agassiz commenced the new series of 

 observations upon which we are about to dwell. 



The comparative study of the different regions of the gla- 

 cier, and of the modifications which the ice undergoes in its 

 course from the superior elevations towards the lower valleys, 

 instantly occurs as one of the most important points. The older 

 authors recognised its importance, and made a distinction be- 

 tween the glacier, properly so called, and the Firn or Neve ; 

 and more recent ones have recognised three distinct regions 

 in all the larger glaciers, namely, the region of compact ice, 

 the region of the Neve, and the region of snow-fields* 



Regarding the first region, or that of compact ice, it is known 

 that the ice becomes harder and harder towards the extremity 

 of the glacier. The presence of a net- work of very fine fissures 

 * — the capillary fissures — had also been ascertained, by which 

 the water of the surface copiously penetrated into the inte- 

 rior ; but these fissures were only known as they had been ob- 

 served upon the surface, and upon the walls of the crevices. 

 It was not positively ascertained if they extended to the inte- 

 rior of the mass, or to what precise depth they reached. Hence, 

 among the objections made to the theory of infiltration, the 

 argument has often been put forward, that previous to admit- 

 ting a general infiltration by the capillary fissures, it was neces- 

 sary to demonstrate the existence of these fissures throughout 

 the mass. Many learned men and able natural philosophers, 

 considered the idea as very problematical, and in opposition 

 to the constituent nature of ice. It was. therefore, only direct 

 experiments upon the infiltrations which could decide the ques- 

 tion. As to the always increasing density of the ice, it was 

 usually attributed to the effect of pressure, but without any 



* These regions have now for the first time been represented in a graphic 

 manner, in a map which, along with M. Agassiz, I have prepared, as an accom- 

 paniment to the German translation of our ascent of the Jungfrau ; the limits 

 of the different regions being there indicated with all the precision which can 

 be attained in a map which has not been constructed upon trigonometrical obs^iV 

 vAtions. 



