66 THE GERMAN ARCTIC EXPEDITION. 



fis Iceland, the largest fields of ice are to be found ; tracts of 

 enormous extent and sometimes more tlian fifty feet in 

 thickness. Between these, and originating from them 

 in the course of time, by their breaking up, are smaller 

 fields called ice-floes ; and these, increased by thawing, 

 by the surrounding driving and pressing, as well as by 

 the waves, break up in small pieces, the real hummocks 

 which prevail at the eastern boundary of the current, at 

 the "ice-line," as well as at the most southerly end. As 

 a last remains of the disturbing process, huge hummocks 

 float about, or cover the broken ice or the wide expanse 

 of sea with small brashes. Eeal icebergs seem almost 

 peculiar to the southern part of the coasts ; such an ice- 

 berg is not formed in the sea, but is a broken piece of 

 glacier moving with its lower part in the sea, and from 

 which at different times large pieces have been broken 

 off" by the pressure of the water, and carried onward by 

 the current. 



The breadth of this ice-current, and also the position 

 of the ice-line is, as may be imagined, very different at 

 different times of the year. Whilst in spring-time it runs 

 about the middle of Iceland past Jan Mayen to the 

 southern point of Spitzbergen, in summer it retreats 

 nearer to the coast, and stretches somewhat in the 

 direction of the west-end of Iceland to the north of Spitz- 

 bergen. Some pieces of ice, under peculiar circum- 

 stances, naturally float very far from this boundary 

 towards the south-east; sometimes even reaching the 

 Faroes. 



But even at corresponding times of the year, the ice- 

 line may occupy very different positions ; much de- 

 pending upon the compactness of the labyrinth of 



