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THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 



of the circle, so there can be little doubt that the Antarctic anti-cyclone extends more to 

 the north as we proceed east, but is subject to seasonal oscillations. This is as Supan 

 has supposed. 



The wind circulation in the vicinity of Graham's Land is of interest, as the west wind 

 system disappears in comparatively low latitudes, showing that this region south of 

 64° S. is probably under the influence of the south polar anti-cyclone. 



The following table shows the mean annual percentage frequency of the winds at 

 several places (see Plate IV.) : — 



It will be seen that in the region of the "Belgica's" drift there was no very pronounced 

 maximum of wind frequency from any particular quarter. It is different, however, at 

 Port Charcot and Snow Hill, where, during half the time, the wind was blowing from 

 S. and S.W., with a secondary maximum from the N.E. It will also be noted how the 

 percentage of calms increases as we proceed south. This in itself is an indication that 

 the austral regions are well outside the west wind area, where the l)arometric gradient 

 is usually steep and calms consequently very rare. At Port Charcot the south and 

 west winds are feeble, and during their occurrence pressure is high, temperature low, and 

 the skies clear ; the north-east winds, however, blow with great force and are relatively 

 warm, causing the temperature even in mid-winter to rise above the freezing point. These 

 north-east winds point to the existence of a low pressure area to the west-north-west of 

 the station in about 64° S., which still further supports our view regarding the increase 

 of pressure to the south. It is not unlikely that the very congested ice conditions of 

 the sea on the east side of Graham's Land may help in the production of a local anti- 

 cyclone, as it is seldom that this sea is clear of ice ; but it is far more probable that the 

 anti-cyclone is a widespread one, whose position is determined by that of the Antarctic 

 continent. 



