414 SCIENTIFIC ADVANTAGES OF AN ANTARCTIC EXPEDITION. 



many indications that the extreme South Polar area is occupiefl by a 

 vast anticyclone, out of which winds blow toward the girdle of low 

 pressure outside the ice bound region. In support of this view it is 

 pointed out that Eoss's barometric observations indicate a gradual rise 

 in the pressure south of the latitude 75° S., and all Antarctic; voyagers 

 agree that when near the ice the majority of the winds are from the 

 south and southeast, and bring clear weather with fall of temperature, 

 while northerly winds bring thick fogs with rise of temperature. 



All our knowledge of the meteorological conditions of the Antarctic 

 is limited to a few observations during the midsummer months, and 

 these indicate that the temperature of the snow-covered Antarctic con- 

 tinent is even at that time much lower than that of the surrounding 

 sea. The anticyclonic area at the South Pole appears therefore to be 

 permanent, and when in winter the sea ice is for the most i^art continu- 

 ous and extends far to the north the anticyclonic area has most i)rob- 

 ably a much wider extension than in summer. This is indicated by the 

 southeasterly winds, which at times blow toward the southern point of 

 the American continent in June and July. 



All observations in high southern latitudes indicate an extremely low 

 summer temperature. In winter we have no direct observations. The 

 mean of Ross's air temperatures south of latitude 63° S. was 28.74° F., 

 which is about the freezing point of sea water, and his maximum tem- 

 peiature was 43.5° F. Both Wilkes and D'Urville observed pools of 

 fresh water on several icebergs, and, when sailing along the ice barrier, 

 Eoss saw ''gigantic icicles depending from every projecting point of its 

 perpendicular clifits,"^ so it is probable that extensive melting sometimes 

 takes place. 



In the latitude of the Antarctic Circle the air is frequently at or near 

 the i)oint of saturation, and precipitation takes place in the form of 

 rain, sleet, snow, or hail. Most of the observations near the ice covered 

 land show, however, a much drier atmosphere, and in all probability 

 precipitation over the Antarctic continent takes iDlace in the form of 

 fine snow crystals, such as is recorded in the interior of Greenland. 



There would ai)pear, then, to be good reasons for believing that the 

 region of the South Pole is covered by what may be regarded practi- 

 cally as a great permanent anticyclone, with a much wider extension in 

 winter than in summer. It is most likely that the prevailing winds 

 blow out from the Pole all the year round toward the surrounding sea, 

 as in the case of Greenland; but, unlike Greenland, this area is prob- 

 ably seldom traversed by cyclonic disturbances. 



But what has been stated only shows how little real knowledge we 

 possess concerning the atmospheric conditions of high southern lati- 

 tudes. It is certain, however, that even two years' systematic observa- 

 tions within these regions would be of the utmost value for the future 

 of meteorological science. 



'Eoss, "Antarctic Voyage/' Vol. I, page 237. 



