CHAP. IV.] 
INLAND-ICE. 
181 
ail important condition for the issue of the conflict which goes 
on here, year after year, century after century, between the sun 
and the ice. For the dark clay and the dark parts of plants 
absorb the warm rays of the sun better than the ice, and 
therefore powerfully promote its melting. They eat themselves 
down in perpendicular cylindrical holes thirty to sixty centi¬ 
metres in depth, and from a few millimetres to a whole metre 
in diameter. The surface of the ice is thus destroyed and 
broken up. 
After the melting of the snow there appears besides a number 
of inequalities, and the clefts previously covered with a fragile 
snow-bridge now gape before the wanderer where he goes 
forward, with their bluish-black abysses, bottomless as far as 
we can depend on ocular evidence. At some places there are 
also to be found in the ice extensive shallow depressions, down 
whose sides innumerable rapid streams flow in beds of azure- 
blue ice, often of such a volume of water as to form actual 
rivers. They generally debouch in a lake situated in the middle 
of the depression. The lake has generally an underground 
outlet through a grotto-vault of ice several thousands of feet 
high. At other places a river is to be seen, which has bored 
itself a hole through the ice-sheet, down which it suddenly 
disappears with a roar and din which are heard far and wide, 
and at a little distance from it there is projected from the ice a 
column of water, which, like a geyser with a large intermittent 
jet in which the water is mixed with air, rises to a great height. 
Now and then a report is heard, resembling that of a cannon 
shot fired in the interior of the icy mass. It is a new crevasse 
that has been formed, or if one is near the border of the ice- 
desert, an ice-block that has fallen down into the sea. For, like 
ordinary collections of water, an ice-lake also has its outlet into 
the sea. These outlets are of three kinds, viz., ice-rapids, in 
which the thick ice-sheet, split up and broken in j)ieces, is 
pressed forward at a comparatively high speed down a narrow 
