THE WEDDELL QUADRANT AND ADJACENT AREAS. Ill 



being located further north than in April. The isoneph of 85 now indicates approxi- 

 mately the position of the pack edge at this season. 



A curious point in regard to the cloud-distribution in the region of the Straits of 

 Magellan is shown by the circumstance that while the maximum for the year is reached 

 at Sandy Point, the minimum is recorded at the neighbouring stations of Evangelists 

 Island and Dungeness. 



Rainfall shows a large increase at Ancud, Point Gallera, and Mocha. 



In June, pressure has risen very generally in the Antarctic and sub-Antarctic 

 regions. It has, however, fallen at the Northern Chilian stations, where it is at the 

 annual minimum, while at the same time rainfall, cloud, humidity, and wind-force are at 

 their annual maximum. The general distribution of pressure remains substantially the 

 same as in May. The Antarctic high is in the same position, but has increased in 

 height : the cyclonic areas in the Weddell Sea and South Pacific are still prominent 

 features of the map, but with pressure about O'lO inch higher than in May. Tempera- 

 ture has fallen about 6° at the Antarctic stations, but elsewhere only half this amount, 

 if we except Ushuaia, where the increased cold of radiation has produced a fall of 5°. 

 The isotherms have now assumed their normal winter position, the most marked feature 

 being the steepening of the thermal gradient south of 60° S. 



Owing to the extension northward of continental conditions brought about by the 

 freezing of the ocean, the amount of cloud has largely diminished, the cloudiest zone 

 being indicated by the isoneph of 80, embracing and to the east of Staten Island, a 

 similar high value being reached off the Chilian coast in 40° S. 



Generally speaking, relative humidity is now at its annual maximum. A marked 

 feature is the excessive rainfall on the Chilian coast in 40° S., where Point Gallera has 

 a mean fall for the month of 19" 1 8 inches. The precipitation diminishes north and 

 south of this latitude. Staten Island also has its maximum fall for the year, viz. 6 '04 

 inches. At South Georgia there occurs the minimum for the year. 



In July, the Antarctic high is shown in about 70° S. and 80° W., with a low- 

 pressure area to the west-north-west and another over the AVeddell Sea. # Pressure has 

 fallen over the whole area to the south of 50° S., west of the meridian of 60° W. 

 To the east of 60° W. it has risen most at the Falkland Islands. 



Southerly and south-west winds are at their annual maximum over large portions of 

 the region comprised between latitudes 52° and 65° S. and longitudes 72° and 65° W., 

 gales from these quarters being frequent to the south of Cape Horn. 



Temperature is now at the minimum for the year, except at places such as Staten 

 Island, which are strongly under oceanic influence. At this season the greatest cold is 



* The long series of observations at the South Orkneys indicate a distinct winter maximum of pressure which is 

 high for the latitude as compared with that recorded in winter by the " Belgica " in long. 87° W., and it would appear 

 that the Antarctic anticyclone in winter is central in about 80° S. and 40° E. That the centre is there rather than 

 at the Pole is connected with the continental conditions induced by the freezing of the Weddell and Biscoe Seas 

 as far north as 60° S. lat., and the relatively higher temperatures that prevail on the other side of the Pole in 

 Victoria Land. 



TRANS. ROY. SOC. EDIN., VOL. XLVII. PART I. (NO. 5). 16 



