I9I5.] IN AIR CIRCULATION OF THE GLOBE. 199 



ciers such as have been described by Chamberhn^^ and Sahsbury-*' 

 from northwest Greenland, and by the Danes in northeast Green- 

 land.-i 



Shackleton, who advanced over the inland-ice in his southern 

 journey on a layer of granular surface snow, returned over a 

 marble-like floor from which the snow had all been swept by the 

 fierce blizzard encountered near his farthest south. On arriving at 

 the Beardmore outlet, he found the lower forty miles of the stream 

 buried deep under great drift accumulations. Scott on his last 

 expedition was much less fortunate while on the plateau, and the 

 burden of his diary is a prayer for strong wind to clear the surface. 

 As is well known, he encountered heavy sweepings of powdery 

 drift snow at the base of the Beardmore, both during his advance 

 and on the return, and his floundering progress through this soft 

 snow was a main contributing cause of the final disaster which over- 

 took the expedition. 



From what is known of the characters of freshly precipitated 

 snow at different air temperatures, it is possible to rather definitely 

 ascribe the enormous snow drifts which piled up for four consecu- 

 tive days upon the Beardmore glacier apron as the chasse neige in 

 process of melting as a result of adiabatic rise in temperature in de- 

 scending currents. This sno\y, Captain Scott tells us, was the fine 

 powdery type, though the temperature was phenomenally high 

 {-\- 2y° — 31° F.), stuck to hair and beard, and produced pools of 

 water everywhere.^- On the return the snow here was soft, loose 

 and sandy, and sledge work was like " pulling over desert sand."-^ 



Marginal Accretions of Snozv. — Valuable new observations 

 which bear strongly upon this point, have been supplied in the pre- 

 liminary report upon the crossing of Greenland by Koch and 



ance of surface level is generally observed to characterize the junctions of 

 tributary with main glacier streams wherever snow drifting plays only a 

 secondary role. 



19/oMr. GcoL, Vol. 3, 180S, P- 579- 



20 L. c, p. 886. 



21 Koch und Wegener, " Die glaciologischen Beobachtungen der Dan- 

 mark-expedition," Med. oiii Gronland, Vol. 46, 1912, Chaps. VI.-VIL, pis. 

 and figs. 



" " Scott's Last Expedition," Vol. i, pp. 335-339- 



23 L. C, p. 396. 



