136 



THE VOYAGE OF THE VEGA. 



[chap. IV. 



down ill 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 numbGr" 

 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 



VIEW FROM THE INLAND-ICE OF GREENLAND. 



After a drawing by S. Berggren, 23rd July, 1870. 



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, 



