NATURE IN MOTION. 03 



threads are said to be negative electric, and consequently 

 repelled by the lower atmosphere, but attracted by the 

 higher layers, which are positive. This remains to be 

 proved, and in the* meantime, we can but repeat : Hearken 

 unto this; stand still and consider the wondrous works 

 of God ! 



Among the well-known causes of such spontaneous and 

 irregular migrations, none is so frequent and so all-powerful, 

 as hunger. The wild ass of the steppes of Asia, of whom 

 it was said that, "the wilderness and barren lands are his 

 dwelling," leaves the deserts of Great Tartary, and feeds 

 in summer to the north and east of Lake Aral ; in fall 

 they migrate by the thousand to the north of India, and 

 even to Persia. The hare of Siberia, and the rat of Nor- 

 way, the reindeer, and the musk-ox, all leave at their 

 season the Arctic regions, and travel, impelled by hunger, 

 to southern latitudes. More regular are the lemmings, 

 a kind of Lapland marmot. Scarcity of food, or over- 

 population drives them once or twice every twenty-five 

 years, in prodigious bands, from the Kolai and Lapland 

 Alps, one species to the east, another to the west. A 

 terrible scourge, they devastate field and garden, ruin the 

 harvest, and hardly spare the contents of houses. Turning 

 neither to the right nor the left, they march on in a 

 direct, straight line, undeterred by mountain, river, or lake, 

 passing boldly through village and town, until their ranks, 

 thinned by numerous enemies, are lost in dense forests, 

 or they reach the Western Ocean, and there end both 

 their journey and their life. Other bands go through 

 Sweden, and perish in the Gulf of Bothnia, so that but 



