760 LT... Ci CLLA MBER, 
and north Pacific ‘‘lows”’ are permanent cyclonic areas with 
inflowing ascending currents attended by high precipitation and 
prevalent fogs. 
Of the two “‘lows”’ that of the north Atlantic is the broader 
and more northerly, and appears to be the more influential factor 
now, as presumably it was in Pleistocene times. The north 
Atlantic ‘low,’ according to both Buchan and Hann, centers 
near the apex of Greenland; the north Pacific “low” centers on 
the Aleutian islands. 
It is not difficult now to understand the peculiar behavior of 
the ice-driit “of the’ polar seas, Bhe Asiatic: “hich jwithweies: 
outflowing currents pushes the ice off the Asiatic coast, while 
the currents inflowing toward the two “lows”’ impel it toward a 
point between the two. The Asiatic “high,” however, develops 
more to the northeast of its center than to the northwest, and 
the North American area of moderately high barometer extends. 
a tongue to the northwest between the two ‘‘lows,” so that the 
two high areas approach each other north of the north Pacific 
“low” and reduce its influence upon the high latitude currents. 
These are therefore directed disproportionately toward the north 
Atlantic ‘‘low,” and give to it a dominating influence. Buchan’s. 
maps of wind-directions for the winter months (when local influ- 
ences are reduced to the minimum) show that the prevailing 
wind currents flow concentrically about the north Atlantic center 
from the Lena on the east to the MacKenzie on the west, a stretch 
of 220° longitude. 
Correlation of circumpolar currents.—But in considering the 
circumpolar circulation as a whole, it is necessary to combine all 
the movements about all these centers to find the true dynamic 
center or the constructive pole of the winds. While such a com- 
bination cannot be accurately made from present data, it is 
obvious that it must place this constructive pole somewhere to. 
the northward and westward of the north Atlantic “low” and 
nearer to it than to either of the other centers.) he jpome 
toward which the ice-drift converges satisfies these conditions, 
and may be taken as nature’s own practical correlation. Possibly 
