102 THE FOKMS OF WATER IN 



far more important that you should realise the way in 

 which the various threads of what we call Nature are 

 woven together. You cannot fully understand an icicle 

 without first knowing that solar beams powerful enough 

 to fuse the snows and blister the human skin, nay, it 

 might be added, powerful enough, when concentrated, 

 to burn up the human body itself, may pass through 

 the air 5 and still leave it at an icy temperature. 



§ 38. The Bergschrund. 



260. Having cleared away this difficulty, let us turn 

 once more to the crevasses, taking them in the order 

 of their formation. First then above the neve we have 

 the final Alpine peaks and crests, against which the 

 snow is often reared as a steep buttress. We have 

 already learned that both neves and glaciers are moving 

 slowly downwards ; but it usually happens that the 

 attachment of the highest portion of the buttress to the 

 rocks is great enough to enable it to hold on while 

 the lower portion breaks away. A very characteristic 

 crevasse is thus formed, called in the German-speaking 

 portion of the Alps a Bergschrund. It often surrounds 

 a peak like a fosse, as if to defend it against the as- 

 saults of climbers. 



261 . Look more closely into its formation. Imagine 

 the snow as yet unbroken. Its higher portions cling 

 to the rocks, and move downwards with extreme slow- 

 ness. But its lower portions, whether from theii 



