.^Ax m uKfflackrsfyf the Mps^Mori '$tf 



wards. ' It is possible that they contain air much rarefied, which 

 disappears, when it is liberated under water. We have not 

 hitherto made exact and decisive experiments on this subject' i'io 

 -iifphe crystals,' or rather the grains of the glaciers of the second; 

 kind, attain their greatest dimensions at the extremity of these 

 glaciers. The more the glaciers are prolonged and extended into 

 the inferior valleys, the grains are the larger. Thus, those of 

 the glacier of Alctsch are greater than those of the glacier of 

 Rosenlaui ; at the base of the former, the crystals have a diame^ 

 ier of more than two inches. Two leagues higher, near the Lake 

 Mbrile, they are only the size of a walnut ; in ascending two 

 leagues farther, at the foot of Faulhorn, they are much lestf 

 still ; and, finally, the glacier passes to the state of the first 

 kind. ' t' ^^ ' jJiiV 



At tK^'boitom of glaciers, the grain is almost of the safflc 

 size at the superior and inferior surfaces, and in the interior of 

 the mass ; but if they approach the superior limit, or, still bet- 

 ter, if they ascend on a glacier of the first kind, even to the 

 highest peaks, they find that the grain increases in dimensions,; 

 from the superior surface even to the bottom. Thus a little 

 above the inferior limit of a glacier of the first kind, at the deptW 

 of some feet, they find the ice in the condition of the second 

 kind ; at a height of isfOOO feet this change only shows itself iBi 

 the lowest. These important facts will serve farther to confirnv 

 the opinion, that every glacier of the second kind commences in 

 the upper regions, under the form of the first ; that this trans- 

 formation commences at the surface, and tliat afterwards^ in the 

 lapse of years, the mass descends into the valley, and, at the 

 same time, approaches the soil by the mere act of the melting of 

 the inferior surface. With time, each grain augments in magniJ 

 tude ; and so explains, to a certain degree, this progression of^ 

 the glaciers, which is an incontestible fact. . > 



The shooting of crystals into each other does not unite ali' 

 the mass of the glacier from the superior to the inferior surface.- 

 The blocks of ice which we have observed, in the same time' 

 that they are decomposed in their crystalline elements, also se^' 

 parate very regularly into strata, which, as long as the cold doei^ 

 not unite them, do not show any trace of that connexkin whicH 

 exists in the mass of each stratum. I have seen, in the Lake of 



