no HOBBS— CHARACTERISTICS OF THE [April 22, 



advocated by von Drygalski, can occur.*^ Such moisture-laden air 

 as can, under normal conditions, reach the interior plateau must 

 descend from higher levels in the anti-cyclone above the central boss, 

 and be distributed by the outward flowing surface currents. From 

 such altitudes the moisture would probably be congealed in the form 

 of fine ice needles, such as are believed to exist in cirrus clouds. 

 The snow which covers the surface at these levels appears, more- 

 over, to have this character. Of greatest interest in this connection 

 is the observation of Nansen that while the sky was, during the 

 time of his crossing, in the main clear, those clouds which were 

 present were generally either cirrus clouds or some combination of 

 cirrus with cumulus and stratus clouds. No cumulus clouds what- 

 ever were observed. In tabular form his results are as follows : 



Form of Clouds. No. of Days. Per Cent. 



Cirrus 23 "^ 44 



Cirro-stratus i? ^5i 33 



Cirro-cumulus iij 21 



Cumulo-stratus 22 42 



Stratus 10 19 



As already stated, such snow as reaches the central area must, it 

 would seem, be derived from the cirrus clouds which at higher 

 levels move in toward the anti-cyclone and descend as surface cur- 

 rents over the "Great Ice." 



Depletion of the Greenland Ice from Surface Melting. 



Eastern and Western Slopes Compared. — Though it is prob- 

 ably not true, as has been claimed by von Drygalski, that the east- 

 ern border of the continent is the locus of nourishment for the ice, 

 it is almost certain that the losses are much greater along the west- 

 ern margins. For this there are several reasons. In the first place, 

 the eastern base is apparently characterized by lower temperatures. 

 The cold ocean current, which carries ice bergs and flows from the 



" " The east is to be regarded as the region of origin of snow, the west 

 as the terminal region of the Greenlandic glaciation." (E. von Drygalski, 

 " Die Eisbewegung, ihre physikalischen Ursachen und ihre geographischen 

 Wirkungen," Pet. Mitt., Vol. 44, 1898, pp. 55-64-) 



