228 ICE ITS FORMS AND FUNCTIONS. 



melts its modicum of ice, and one by one, as they ascend in 

 the same direction, they gradually pierce the thickest sheet, 

 cutting rounded holes as clean and straight (in the words of 

 Sir E. Belcher) as if they had been bored by an auger. In 

 general, however, the heat is retained and diffused through- 

 out the water, while all above is stark and lifeless at tem- 

 peratures 50, 60, and even 70 below zero. How wonder- 

 ful the provision by which the density and temperature of 

 the ocean are preserved for the wants of its animal life ! 

 how perfect the scheme of compensation by which the most 

 powerful agents are held in check, and the balance and 

 equipoise of nature sustained ! 



It is at this stage, when the thaws and currents of a brief 

 summer have broken up the polar ice into " floes " and 

 " packs " and " streams," that we find it associated with the 

 land-formed "berg;" the whole drifting to warmer lati- 

 tudes, there to be dissolved, and to lose themselves once 

 more in the liquid mass of the ocean. Purely sea-formed 

 ice has no perceptible geological effect, but much of it is 

 accumulated along shore and under cliffs and precipices 

 (the " ice-foot " of the sailor), and this, along with the true 

 iceberg, is generally laden with soil, sand, gravel, bouldery 

 blocks, and other spoils of the land, and these, as the ice- 

 masses melt away, are dropped broadcast over the floor of 

 the ocean. All that is, or has ever been, ground and worn 

 from the surface of Greenland by the ice-sheet that envelops 

 it, has been spread by the iceberg on the bottom of the 

 North Atlantic. Water in the solid state is as much a 

 wearer and transporter of the land as water in a liquid state. 

 The ice-stream grinds and degrades as surely as the water- 

 stream ; and the burden of both ultimately finds its way to 

 the depths of the ocean. Nay, ice is the more potent of 

 the two the " berg " bearing blocks and boulders which 

 no current of water could move, and scattering its burden 



