368 THE BEAUTIES OF 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 must 
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 mdeed 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 
