228 Mr Edward Collomb on the 



merit observable in all the masses of snow which still exist 

 on our mountains in the spring and during a part of the 

 summer. 



This movement, which does not proceed from sliding on 

 an inclined plane, but from an expansive motion (mouvement 

 d' expansion) arising from its partial conversion into ice, as- 

 similates these masses to true glaciers, although, it is true, 

 in very small proportions. 



On the 6th April 1845, we explored the bottom of the 

 valley of Wilden stein (Haut-E-hin). A few weeks before, a 

 pretty large avalanche had detached itself from the Col du 

 Rothenbach, and, after a transit of about 1000 or 1200 me- 

 tres, had accumulated a great quantity of trees, blocks, clay, 

 sand, and considerable masses of snow at the foot of the 

 couloir. 



A note relating to this fact, inserted in the Comptes Ren- 

 dus of the Institute, states the following particulars : — 



" At the points where the avalanche has collected the snow 

 in a great mass, and when the rivulet has formed, by its 

 melting, pretty distinct sections, we have studied, with ease, 

 the different stratifications of the snow, the passage of the 

 snow into neve, and from neve into ice, such as MM. Agas- 

 siz and Desor observed in the high regions of the Alps. In 

 a thickness of some metres, the strata succeed each other in 

 the following order : — 



" Minute neve, or powdery snow. 

 Large-granular neve. 

 Ice of neve. 

 Vescicular ice, 

 Compact ice, resting on the ground. 



*' Before the snow could become stratified in this manner, 

 it must have been subjected to many atmospheric influences 

 since its accumulation ; among others, a moderate heat dur- 

 ing the day, and cold night, circumstances which, by causing 

 a partial melting, have allowed the mass to imbibe water, 

 and then to congeal. 



" On the declivities where we observed them, the masses 

 of neve having imbibed water, already exhibited a motion of 

 their own. Of this we satisfied ourselves, by an attentive 



