128 ICE AND GLACIERS. 



Lastly, when streaked cylinders of ice formed from pieces of 

 snow and ice are pressed into discs, they become finely streaked, 

 for both their clear and their opaque layers are uniformly ex- 

 tended. 



Ice thus striated occurs in numerous glaciers, and is no doubt 

 caused, as Tyndall maintains, by snow falling between the blocks of 

 ice ; this mixture of snow and clear ice is again compressed in the 

 subsequent path of the glacier, and gradually stretched by the 

 motion of the mass : a process quite analogous to the artificial 

 one which we have demonstrated. 



Thus to the eye of the natural philosopher the glacier, with 

 its wildly heaped ice-blocks, its desolate, stony, and muddy sur- 

 face, and its threatening crevasses, has become a majestic stream 

 whose peaceful and regular flow has no parallel ; which, accord- 

 ing to fixed and definite laws, narrows, expands, is heaped up, 

 or, broken and shattered, falls down precipitous heights. If we 

 trace it beyond its termination we see its waters, uniting to a 

 copious brook, burst through its icy gate and flow away. Such 

 a brook, on emerging from the glacier, seems dirty and turbid 

 enough, for it carries away as powder the stone which the 

 glacier has ground. We are disenchanted at seeing the won- 

 drously beautiful and transparent ice converted into such muddy 

 water. But the water of the glacier streams is as pure and 

 beautiful as the ice, though its beauty is for the moment concealed 

 and invisible. We must search for these waters after they have 

 passed through a lake in which they have deposited this pow- 

 dered stone. The Lakes of Geneva, of Thun, of Lucerne, of 

 Constance, the Lago Maggiore, the Lake of Como, and the Lago 

 di Garda are chiefly fed with glacier waters ; their clearness and 

 their wonderfully beautiful blue or blue-green colour are the 

 delight of all travellers. 



Yet, leaving aside the beauty of these waters, and considering 

 only their utility, we shall have still more reason for admiration. 

 The unsightly mud which the glacier streams wash away 

 forms a highly fertile soil in the places where it is deposited ; 

 for its state of mechanical division is extremely fine, and it i& 

 moreover an utterly unexhausted virgin soil, rich in the mineral 



