108 MR ROBERT C. MOBSMAN ON THE METEOROLOGY OF 



W., and N.E. in the vicinity of and to the south of the South Shetlands. On the west 

 side of Graham's Land from 63° to 64° S. lat. winds are somewhat variable, and the 

 combined values from the various summer expeditions give no great preponderance of 

 any one wind. It is probable that this region is alternately influenced by the above 

 two low-pressure areas. The Antarctic high is considerably reduced, and is shown by 

 the isobar of 29"30 inches which covers the extreme south of the Bellinghausen Sea, 

 the winds being almost wholly from the north-east, east, and south-east in 70° S., 87° 

 W. The strongest winds in this region are from the north-east, and the lightest from 

 the west. 



As compared with the previous month, temperature has risen everywhere, the rise 

 being from 2 to 3 degrees, except at the Antarctic stations, where it amounts to 1 degree 

 only. The isotherms have assumed their typical summer form, bending considerably 

 to the south to the west of 50° W. A noticeable feature in this connection is the high 

 temperature and dry atmosphere which prevails over Tierra del Fuego and Patagonia to 

 the south and west of Sandy Point. 



At most places, except the Antarctic and strictly oceanic situations, temperature is 

 now at its annual maximum. The amount of cloud has considerably increased over the 

 region south of 60° S., but has diminished over the mainland of South America. The 

 isoneph of 95 now appears over the northern part of the Weddell Sea, or over that 

 region where the ocean temperature is relatively high. 



Rainfall is now at its annual maximum over a region running along the 53 degrees 

 of latitude between the meridians of 68° and 75° W., reaching a total of 12 - 82 inches 

 at Evangelists Island on the Pacific side of the straits, where north-west winds blow 

 with greater frequency than during any other month of the year, and, since they are on- 

 shore winds, are accompanied by heavy rainfall. 



The temperature-difference between the east and west sides of the Straits of 

 Magellan is also at a maximum, Dungeness being 6°*2 warmer than Evangelists Island, 

 as a result of the excessive precipitation and overcast sky prevailing at the latter region. 

 At Ancud, Port Gallera, and Isle Mocha rainfall is at a minimum for the year, this 

 region being now well within the influence of the South Pacific high. 



In February, the most marked feature in the pressure-distribution for the month is 

 the complete recession of the Antarctic high from the area under discussion. This 

 fall of pressure is most pronounced in the Bellingshausen Sea, and extends, though in 

 a much smaller degree, over to Graham's Land and the Weddell Sea. Low-pressure 

 areas are again shown to the east and west of Graham's Land. The former low- 

 pressure area probably extends a very long way to the east, with the isobar of 29 "2 

 assuming a northerly trend east of the meridian of Greenwich. Observations over a 

 combined period of forty-five days show a reduction equal to 0*22 inch between situations 

 in 37° W. and 64° E. longitude on the parallel of 62^-. The few observations that we 

 have south of the Antarctic circle show but little difference of pressure between 23° W. 

 and 50° E. 



