THE VARIATION OF GLACIERS. IV 219 



Spitsbergen. — The most important work on these islands is 

 that of Baron de Geer, who has visited them several times. He 

 finds from the maps and photographs that the glacier of Sef- 

 strom has advanced about four kilometers since 1882, but at 

 present seems to be retreating. On the other hand, the glacier 

 of von Post has retreated slightly since 1882 Sir Martin Con- 

 way found that the glacier, which he called the Ivory Gate, has 

 advanced very considerably since 1870. The best accounts of 

 the observations of Sir Martin Conway's party are found in the 

 Geographical Journal, April 1897, and in the Quarterly Journal of 

 Geology, 1898, Vol. LIV, pp. 197-227. 



Dr. A. Hamberg has written on the parallel structure of 

 glaciers. He thinks that this, as well as the similar structure 

 observed in Antarctic ice, is due to stratification. 1 He thinks, 

 also, that the movement of these glaciers is due to the slipping 

 of successive layers over each other, and that there is practically 

 no differential movement in the layers themselves. Dr. Ham- 

 berg thinks that in these latitudes greater pressure is necessary 

 to convert the neve into solid ice than in warmer climates, and 

 he thus explains the fact that many of these glaciers are not 

 very thoroughly consolidated. 



Franz Josef Land. — Dr. Nansen tells us, in the account of 

 his celebrated polar expedition, that there are no true glaciers 

 on these islands, but that they are covered with masses of ice 

 sloping toward the sea. These are apparently of the same type 

 as those described by Dr. Hamberg. Dr. Nansen also tells us 

 that he found indications of the existence of a former glacier all 

 along the northern coast of Siberia. He also gives us interest- 

 ing descriptions of the folding and crushing of the polar ice as a 

 result of ocean currents. 2 



Greenland. — A Danish expedition visited the island of Disco 

 in 1897 an d examined the glaciers of Blosedalen, which had 

 been visited in 1894 by Professor Chamberlin. They found that 



"Rev. O. Fisher gave the same explanation of the horizontal markings in Ant- 

 arctic ice. Phil. Mag. (5) 1879, Vol. VII, pp. 381-393. 



2 Report of Professor Nathorst. 



