144 ICE AKD GLACIERS. 



again broken, placed in the mould, and pressed into a 

 cylinder, the air may gradually be more and more elimi- 

 nated, and the ice be made clearer. No doubt in glaciers 

 the originally whitish mass of neve is thus gradually 

 transformed into the clear, transparent ice of the glacier. 



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 extended. 



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 hav^e demonstrated. 



Thus to the eye of the natural philosopher the glacier, 

 with its wildly-heaped ice-blocks, its desolate, stony, and 

 muddy surface, and its threatening crevasses, has become 

 a majestic stream whose peaceful and regular flow has no 

 parallel ; which, according to fixed and definite laws, nar- 

 rows, 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 wondrously 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, 



