88 



DISCOVERY REPORTS 



At the greater depth of the maximum salinity of the current, the content between 

 52 and 56^° S is greatest in April, less in January and least in October. 



Around South Georgia the silicate content in the upper part of the current is about 

 3500 mg., and at the depth of maximum salinity it is about 4500 mg. The available data 

 are scanty, and although some seasonal variation no doubt exists, no direct evidence of 

 it has been obtained. 



No data exist for the silicate content in the warm deep layer in the western part of 

 the South Atlantic Ocean, but in April 1934 some observations were made between 

 53I and 6i^° S outside the Scotia arc just to the east of the South Sandwich Islands. 

 Here the content in the upper part of the current was about 4100-4750 mg., and between 

 4650 mg. and 5350 mg. at the depth of the salinity maximum. The most southerly station 

 in these observations was made in the cold eastward-flowing Weddell Sea water in 

 which the maximum temperature of the warm deep water was only 0-44° C. The silicate 

 content in this deep current was greater than at the more northerly stations and amounted 

 to 5850 mg. in the upper layers and 6100 mg. at the depth of maximum salinity. 



The silicate content of the warm deep water across the Southern Ocean in the Atlantic 

 sector is summarized in Table VI, which represents observations made in February 

 1935 in a cruise from the south of the South Sandwich Islands to the ice-edge at the 

 eastern entrance to the Weddell Sea and continued in a series of zigzags from and to 

 the ice-edge as far east as 44 E. In general the silicate content south of 6o° S decreased 

 towards the east and north, the highest values being recorded across the Weddell Sea. 



Table VI 



* Denotes an ice-edge station. 



