756 T. C. CHAMBERLIN 
arid belt stretches north of east across Africa and Asia until in 
Mongolia it lies between 30° and 50° north latitude. That is to 
say, in this stretch of 70° or 80° in longitude it has advanced 
20° in latitude. If now we select the meridian at 90° east, at 
or about which the desert area reaches its northern culmination, 
and follow this through the pole to a point 20° beyond on the 
meridian of 90° west, we are in the vicinity of the point towards 
which the arctic. ice-drift seems. to ‘concentrate. | And ai we 
follow the same meridian southward we reach the point in the 
Mississippi valley where the ice-sheet had its southernmost exten- 
sion. It is to be noted further that this last point coincides 
with the region where a large percentage of the cyclones which 
descend from the northwest curve about and take northeasterly 
courses. 
If there were space here to enter into other particulars, addi- 
tional coincidences of an apparently significant nature might be 
found. The inference drawn is that the axis of the main polar 
whirl, if indeed the polar movement can be called a whirl, is not 
coincident with the axis of the earth, but hes at some point 
southward from it in the vicinity of the meridian of 90° west 
longitude and 20° more or less distant from the pole. 
Indications of meteorological data.— As just implied, the idea 
entertained is not that there is a simple polar whirl whose axis 
is located here, but that the rather complex movements of the 
polar atmosphere, when combined and correlated, give a theo- 
retical or constructive pole in this region. What is meant by 
this will appear more specifically from a study of the available 
meteorological data. Unfortunately these are yet quite imper- 
fect and’ partially uncorrelated, and hence I have given prece- 
dence to the natural correlation expressed in the ice-drift. The 
International Circumpolar Commission has not yet combined 
and discussed its data. It may therefore be most convenient to 
have recourse to Buchan’s’ or Hann’s? meterological maps. for 
™Challenger Reports. Physics and Chemistry, Vol. 11, Atmospheric Circulation. 
Maps 51 and 52. These include the main data gathered by the International Circum- 
polar Stations. 
? Berghaus Physical Atlas. 
