POLAR ICE. — INFLUEl^CE ON THE SEA. 305 



river. So long as the ice hangs together, and pre- 

 serves its continuity, it sustains but little loss from 

 the most violent surges ; hut whenever the sea 

 breaks through it, like an army dispersed and re- 

 treating in confusion before a victorious enemy, the 

 pieces flee before the sea, increase rather than di- 

 minish the swell, are overrun by the foaming waters, 

 and subjected to a rapid dissolution. 



Thus, while a small stream of compact ice sup- 

 presses a swell, a large body of heavy ice, when 

 loose or unconnected, produces little effect, the sea 

 being found to penetrate with little diminution for 

 many leagues. A swell among ice is discovered by 

 the breaking of fields, or by the motions of loose 

 pieces, when it cannot be otherwise observed. In 

 some cases it becomes a useful guide to the invol- 

 ved navigator, by pointing out, in the direction in 

 which it penetrates, the way of escape. In thick 

 weather, especiciUy, it is often the means of extri- 

 cation to ships the most awkwardly entangled 

 among ice, and preserves them from being deeply 

 and dangerously beset. 



8. A balance of power seems to be preserved be- 

 tween the wasting influence of the waves and the 

 solidity and increasing property of the polar ice ; 

 the former preventing the undue enlargement of 

 the boundaries of the ice, and the latter defying any 

 extensive, or at least permanent, inroads into the 

 situations usually occupied by it. For, as fast as 



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