34 THE HAEMONIES OF STATUKE. 



of the sun, disappear from the hills, and soon make room for a 

 rich carpet of verdure. 



Thus the lavines are of incalculable advantage to the Alpine 

 mountaineer, who now drives his herds on many a pasture- 

 ground which, but for them, would be condemned to perpetual 

 sterility. 



It might be supposed that the snow, filling the deep gullies or 

 basins of the higher Alps, and thence pouring in streams of 

 solid ice into the valleys, must be eternally fixed on earth, 

 and that their imprisoned waters could never find their way back 

 again to the ocean. The glaciers of the Mont Blanc or of the 

 Bernese Oberland seem perennially to defy the warmth of sum- 

 mer; but their immobility is merely apparent, for the pres- 

 sure of the superincumbent masses is so great as to force them 

 perpetually downwards as if they were a viscous body, until at 

 length the consumption below equals the supply above. 



Thus slowly, indeed for the velocity of the great glaciers of 

 the Alps rarely exceeds two feet a day but yet not less surely 

 than if they bounded in foaming cataracts down the valleys, or 

 rolled in rapid currents through the plains, the consolidated 

 waters above the snow-line are ultimately restored to their parent 

 seas. 



In the same manner Greenland, Spitzbergen and many other 

 mountainous countries of the Arctic zone, divest themselves of 

 the snows which cover their dreary wastes, and thus an accu- 

 mulation is prevented which might have been dangerous to the 

 whole economy of organic nature. 



The property of water to expand and thus to become lighter 

 on assuming the solid form of ice, is of the greatest importance 

 to the maintenance of organic life over a great portion of the 

 globe. 



If ice were heavier than water, the beds of the rivulets and 

 rivers, of the ponds and lakes, in the higher latitudes would be 

 covered with a sheet of congealed water as soon as the first frosts 

 of winter appeared, and in a very few days the mightiest streams 

 would be converted, throughout their whole depth, into one solid 

 mass, which even a long summer would hardly have been able 

 to thaw, or which in many cases would have triumphed over all 

 its efforts. But ice remaining on the surface, and being, like 

 snow, a bad conductor of heat, increases but slowly in thickness 

 as the rigours of winter increase, and thus, even in Siberia, the 



