108 ACCOUNT OF THE ARCTIC REGIONS. 



tlie Sim break out and operate on the upper surface 

 so as to dissolve it, the water which results runs 

 into the porous mfiSR, progressively fills the cavi- 

 ties, and being then exposed to an internal tempe- 

 rature sufficiently low, freezes the whole into a solid 

 body. Or if, when the ice has been cooled by a 

 low temperature, a fog or sleet occur, it is frozen as 

 it falls, and encrusts the body of the iceberg with 

 an additional varnish of ice. 



Icebergs are as permanent as the rocks on which 

 they rest ; for though large portions may be fre- 

 quently separated from the lower edge, or, by large 

 avalanches from the mountain summit, be hurled 

 into the sea, yet the annual growth replenishes the 

 loss, and, probably on the whole, produces a perpe- 

 tual increase. But the annual supply of ice is not 

 only added to the upper part, but also to the preci- 

 pitous crest facing the sea ; which addition being 

 run into, or suspended over the ocean, admits of 

 new fragments being detached, and of tlie renewal 

 of the vitreous surface which it presents to the eye 

 after each separation. In some places, indeed, 

 where the sea is almost perpetually covered with 

 ice, the berg or glacier makes its way to a great ex- 

 tent into the sea, until it reaches the depth in the 

 water, of several hundreds of feet ; and then being 

 capable of large dismemberments, gives rise to the 

 kind of mountainous masses or icebergs, found 

 afloat in such abundance in the sea to the westward 



