218 HOBBS— ROLE OF GLACIAL ANTICYCLONE [April 24, 



taken in the winter season, it is well nigh certain that the zone of 

 control would have been found much wider. 



Effect of the Greenland Anticyclone Upon Migrating 

 Cyclonic Depressions. 



Supposed Passage of Cyclones Across the Continental Glacier of 

 Greenland. — A question which has been raised in connection with 

 the Greenland continental glacier concerns the interaction of the 

 glacial anticyclone and the migrating cyclones which have been sup- 

 posed to move in toward the continent. Upon this assumption it 

 might be held, upon the one hand, that the cyclone temporarily 

 overwhelms the anticyclone, and " springing over it " continues upon 

 its course ; or, upon the other, that the cyclone is extinguished by 

 the greater vigor of the anticyclone. Evidence which is now fast 

 accumulating shows that, if the cyclones really advance toward the 

 anticyclone, they are at least halted at its margin, and that both 

 become parts of a system of exchanges planetary in its scope. 

 There is, however, upon the assumption stated the possibility that 

 an especially vigorous cyclone in approaching the Greenland coast 

 during one of the weaker stages in the anticyclonic strophe, may 

 make its influence felt not only upon the near side of the anticyclone 

 but beyond it as well. 



Hansen's Observations. — Nansen's conclusion after his crossing 

 of Greenland was, that "the plateau seems to be too high and the 

 air too cold to allow depressions or storm centers to pass across, 

 though, nevertheless, our observations show that in several in- 

 stances the depressions of Baffin's Bay, Davis Strait and Denmark 

 Strait can make themselves felt in the very interior. We experi- 

 enced, also, one instance of the crossing of a depression in the 

 storm center which passed over us on September 8. This must have 

 been, according to Professor Mohn, a secondary depression which 

 lay over Baffin's Bay some days before."^'^ This was, however, in 

 latitude 64° where the inland-ice is extended southward in a rela- 

 tively narrow tongue. According to de Quervain on but one occa- 

 sion during the period of his observations on the Greenland west 



*^ " First Crossing of Greenland," Vol. 2, p. 496. 



