l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8j 



of air 4,000 meters deep over the whole of Europe on an average 

 of 10°. 



I have not attempted to evahiate the effects of the present ice cap 

 on Greenland or of the present altitude of the land surface, as all 



Fig. 5. — Midwinter isotherms at the present time. 



I wish to do in this brief discussion is to emphasize in a graphic way 

 the major thermal effect of land and water. 



The Arctic is an oceanic basin and shows a remarkable climatic 

 contrast with the elevated glacier-covered Antarctic continent. A few 

 of the probable climatic effects which would follow if the Arctic re- 



