32 LEAVES FROM TIIK BOOK OF NATURE. 



men now painfully climb to look down* upon the sunny 

 plain, were once mere loose, fragile sand down in the 

 deep of the sea. They are still mixed with countless 

 shells, the bones of fishes, and a thousand relics of their 

 former home. On the other hand, we know that large 

 tracts of sea-bottom once belonged to the firm land, en- 

 joyed air, light, and warmth, and abounded with life of 

 every kind. But the sea came and buried them in 

 eternal darkness. For the ocean, also, the infinite, is not 

 the same to-day that it was yesterday it changes form 

 and shape like everything else on earth. The very heart 

 of the earth is restless. Its glow and its pulse are felt 

 through the whole globe, and in its gigantic vigor it 

 seems ever anxious to break the fetters that hold it a 

 captive. For the earth longs to live, to live in com- 

 munion with the great elements around it and volcanoes, 

 with their huge, gaping craters, must serve to keep up 

 the desired intercourse between its unknown interior and 

 the atmosphere. Fused, molten stones are thus dragged 

 from their hidden resting-places in the depths of the 

 earth, passed through fiery ovens, and at last, in fierce 

 fury, thrown out of volcanoes, where, as lava streams, they 

 soon become solid, fertile, and fruit-bearing, or form new 

 mountains on land, new islands in the ocean. 



Even now, stones still migrate, thanks to their old 

 friends ice glaciers of vast, gigantic size, that move foot 

 by foot. Their motion is slow but sure: the glacier of 

 Grindelwald advances only about twenty-five feet a year, 

 but a signal-post fastened to a large granite block em- 

 beded in the Unteraar glacier progressed at the rate of 



