Ascent of the Jungfrau in 1841. 299 
compact, although of a deeper tint than the rest of the walls. 
Our guides all agreed in affirming that each of these layers re- 
presented the snow fallen in one year, and this explanation ap- 
peared to us, in reality, the most natural. With regard to 
the narrow bands of ice which separated the beds of snow, 
they are undoubtedly owing to the action of the sun, which 
took effect successively during a summer on the surface of all 
the annual beds. 
On continuing our route, we still met with many fissures 
similar to that just described, and soon became certain that 
the surface on which we walked was wholly undermined, for, 
on looking into an open crevice, we usually saw it prolonged 
into the interior of the mass, far beyond its superficial limits ; 
others were open at the surface throughout their whole length. 
In order to account for the formation of these fissures, it is 
not necessary to have recourse to an inequality of tension si- 
milar to that which is supposed to act in the mass of glaciers, 
properly so called, or the névé, when crevices are formed in 
them. Sucha tension would be even inadmissible, as the mass 
does not possess sufficient adherence. According to all ap- 
pearance, things proceed, in this instance, in a much simpler 
manner. The crevices are nothing more than an effect of the 
declivity of the ground; what proves this is, that they have 
neither the continuity nor the regularity of glacier-fissures, 
and that they are everywhere found on great declivities, where 
they in general attain a very considerable size (from 30 to 100 
feet, a breadth which is seldom witnessed in glaciers, properly 
so called). It is to be observed, besides, that when these rents 
are concealed, it is not, as in the névé or glacier, by a roof of 
fresh snow. I examined attentively the edge of one of these 
crevices, and I saw that the beds of snow in it were perfectly 
homogeneous from above downwards, and corresponded up 
nearly to the surface ; whence I concluded, that when a fis- 
sure is concealed, it is commonly because the separation has 
not extended to the surface. 
The fact that the crevices and cavities of these plains of 
snow exhibit an azure hue, is not unimportant; it is a new 
proof that this tint is peculiar to the water of our mountains 
in whatsoever form it is found. Whether liquid, in the state 
