FLOATING ICE— ICEBERGS. 



71 



The formation of icebergs in polar regions, and their drifting into 

 warmer latitudes, to be melted there, are evidently a necessary conse- 

 quence of the great laiv of circulation, for otherwise ice would accumu- 

 late without limit in these regions. But, by glacial motion, the excess 

 is brought down to the sea, broken off as icebergs, carried southward 

 by currents, and there melted and returned into the general circulation 

 of meteoric waters. 



General Description. — The number of icebergs accumulated about 

 polar coasts is almost inconceivable. Scoresby counted 500 at one 



view. Kane counted 280 of the first magnitude at one view. They are 

 often 200 and sometimes even 400 feet high, and the mass above water 

 66,000,000 cubic yards (Dr. Kink). As the specific gravity of ice is 

 0*918, if these were solid ice, there would be but about one twelfth 

 above water ; but as glacier-ice is somewhat vesicular, there is about 

 one seventh above water. The thickness of some of these icebergs 

 must therefore be 2,000 to 3,000 feet, and their volume near 500,000,000 

 cubic yards, which is about equivalent to a mass one mile square and 



Fig. 67. 



