430 LIFE OF HORACE BENEDICT DE SAUSSURE 



During the following winter these gape fill with snow ; this snow, satu- 

 rated with water, turns into ice ; the edges of the new ice next the 

 mountain are covered with fresh debris ; these covered banks move 

 in succession towards the middle of the glacier, and it is thus that 

 are formed the parallel ridges that move obliquely with a composite 

 movement resulting from the slope of the trough towards the middle 

 of the glacier and the slope of the same trough towards the lower 

 valley.' 



De Saussure's observation is here singularly at fault. Glaciers 

 are not in the habit of waxing laterally by the help of plasters of 

 winter snow locally applied, nor do they at any time of the year 

 slope downwards to their centre, though, where the glacier has 

 shrunk, old lateral moraines may occasionally rise above it. 



Again, of the surprising abilities of the ice-stream as a 

 sledge, or carrier, de Saussure had a very inadequate idea. He 

 mentions here and there that boulders have been brought to their 

 present site by the advancing ice, but this fact never suggested 

 to him that a former extension of the ice might be the key to many 

 of his perplexities. The idea of a glacial epoch, or of several, 

 never occurred to him. The great belt of granite boulders that 

 girds the wooded slopes of the vale of Sallanches below Combloux, 

 the erratic granite blocks near Monthey and on the Jura, the vast 

 series of moraines that encircle the mouth of the valley of Aosta 

 below Ivrea, failed to tell him their story. He was too entirely 

 convinced that all such phenomena owed their origin to gigantic 

 catastrophes, or floods, to look for any less heroic agency. ' The 

 explanation/ he writes, ' I have given of the origin of these frag- 

 ments of primitive rocks ought to be sufficient for naturalists. 

 They are aware that granite boulders do not spring up in the earth 

 like truffles, or grow like pines on limestone. So the only possible 

 difference of opinion on the matter is whether the transporting 

 force was a catastrophe or a deluge.' [Voyages, 209.] 



Controversy still smoulders over the exact constitution of 

 the substance of the glacier. Students may argue or quibble 

 over terms, but no one at the present day will deny that glacier 

 ice possesses qualities which, whether we call it viscous, or plastic, 

 or, with Heim, ' thick -flowing ' (dickflussige), assimilate it rather 

 to a semi-fluid than to a solid body. Of the inner structure 

 of the ice, of the character of its particles, matters recently 



