lieport of the Researches of M, Agassh, 169 



neither the capillary fissures, nor exhibit the blue bands I and 

 how do they make their appearance all of a sudden ? Finally, in 

 virtue of what action is it that the transformation of the Neve 

 into ice takes place from below upwards, instead of proceed- 

 ing from above downwards ? As to the limits of the Neve, it 

 has been observed to be tolerably constant among the Alps ; 

 although this precision has evidently been exaggerated. Ad- 

 ditional researches into this matter must still be under- 

 taken. 



The third region, which comprehends the snow-fields, is 

 the least known of all. But few naturalists had studied these 

 elevated regions, and those who had traversed them had not 

 contributed much respecting the extraordinary phenomena 

 which are there witnessed. It is without doubt known that 

 it is there that t4ie snows annually fall which feed and main- 

 tain the glaciers, and that the snow which falls during the 

 winter upon the lower parts of the glaciers, melts during 

 summer, without contributing, in a direct way, to the forma- 

 tion of the ice. But all our ideas concerning the history of 

 the snow in these immense circuses have hitherto been very 

 imperfect. We had not even a satisfactory knowledge of the 

 form under which it habitually falls, — whether as flakes, or in 

 fine powder, or as minute grains. No more had the particular 

 form of the crevices in these elevated regions, which are dif- 

 ferent from those of the glaciers and the Neve, been eluci- 

 dated. Finally, we were completely ignorant of what became 

 of the horizontal and regular stratification, which is seen upon 

 the sides of those abysses as deep as the eye can penetrate, 

 and of which no trace is to be found in the crevices of the 

 glaciers properly so called. 



Theory was still more at a loss to explain the phenomena 

 which are witnessed upon the highest summits, and the data 

 wc possessed concerning the state of the icy masses of these 

 regions was still more contradictory. It was admitted that 

 there the temperature was always at 32'' F. or below it, and 

 yet we talked of ice upon the highest peaks. Here there was 

 evidently an exception to the common rule ; and this ice 

 formed above the fields of snow, implied particular condi- 

 tions which had not hitherto been recognised. There was 



