368 THE BEAUTIES OE NATURE chap. 



those regions it snows, if not incessantly, at 

 least very frequently, and the snow melts but 

 little. As far as the eye can reach nothing is 

 to be seen but snow. Now this snow niust 

 gradually accumulate, and solidify into -ice, 

 until it attains such a slope that it will move 

 forward as a glacier. The enormous Icebergs 

 of the Southern Ocean, moreover, show that 

 it does so, and that the snow of the extreme 

 south, after condensing into ice, moves slowly 

 outward and at length forms a wall of ice, 

 from which Icebergs, from time to time, 

 break away. We do not exactly know what, 

 under such circumstances, the slope would 

 be ; but Mr. Croll points out that if we take 

 it at only half a degree, and this seems quite 

 a minimum, the Ice cap at the South Pole 

 must be no less than twelve miles in thickness. 

 It is indeed probably even more, for some of 

 the Southern tabular icebergs attain a height 

 of eight hundred, or even a thousand feet 

 above water, indicating a total thickness of 

 the ice sheet even at the edge, of over a mile. 

 Sir James Ross mentions that — " Whilst 

 measuring some angles for the survey near 



