272 Professor Agassiz on the Glacier Theory. 



the cause which determines this linear and continuous disposi- 

 tion of these vertical lamina?, but it seems to me that the 

 first impulsion of this structure is caused by a molecular move- 

 ment of the neve soaked with water, and purified by the run- 

 ning of the water according to the line of the greatest slope. If 

 this were once established, it would not be at all extraordinary, 

 that, in the lower part of the glacier, and notwithstanding the 

 changes its course might undergo, this original disposition 

 should be maintained by the direction which it would impress 

 on the water that infiltrates Into its mass by penetrating from 

 the surface to the interior. It is at least only in this way that 

 I can explain the more or less considerable obliquity of the 

 laminae on the outside of the moraines, and at the edges of glaciers 

 where the largest quantity of water circulates ; and it is only 

 by this means that we can explain the sinuosities and the con- 

 tours that they form, when the masses are displaced from their 

 natural direction during the long course of their descent from 

 the high regions towards the extremity of the glaciers. It is 

 well worthy of remark, that the stratified fields of snow of the 

 highest slopes of the Alps do not present any trace of this 

 lamellar structure, and that in the neve^ where it passes into 

 glacier,* this structure is superficial, or only penetrates a few 

 feet into the mass ; it is only in the main course of the glacier 

 that it seems to me to be well developed and to penetrate 

 very deeply ; at the lower extremity it gradually disappears. 

 It still remains to be determined if traces of it exist at the in- 

 ferior surface of the mass of the glacier. 



* I only wish to describe in tliis article the facts relative to glaciers pro- 

 perly 80 called, because these are more immediately connected with the 

 theory of progression by infiltration. It would have led me too far to have 

 detailed the new observations which have been made on the fields of snow 

 of the highest regions, and on the various phenomena presented by the 

 nh'i. M. Desor and I have endeavoured to delineate the limits of these 

 three regions (the fields of snow, tlie neve, and the glaciers), on a map of the 

 glaciers of the Bernese Oberland, which accompanies the narrative of our 

 ascent of the Jungfrau, by M. Vogt. (Jent and Gassmann, Soleure, 

 1842.) 



