1 6 THE CLIMATE OF AUSTRALASIA 



second important change in the popular British 

 classification has been made by calling the 

 gathering of waters south of the latitude of 

 40 S., the Southern Ocean. This innovation 

 has been sanctioned by the English Admiralty, 

 and is adopted on recent charts ; though the 

 official Sailing Directories still divide the 

 Southern Ocean between the South Atlantic, 

 Indian, and South Pacific Oceans. Recent 

 oceanographic work has supported the claim of 

 the Southern Ocean to recognition as an in- 

 dependent geographical unit, but in a some- 

 what restricted sense. Its northern boundary 

 is generally defined as the 4<Dth parallel of south 

 latitude ; but this limit is artificial and is no 

 longer necessary. The line that marks the 

 northernmost extension of the Antarctic drift 

 ice has also been proposed as the boundary of 

 the Southern Ocean ; but it also is useless, as 

 the limit of the drift ice varies from year to 

 year, and, in 1894, an Antarctic iceberg floated 

 across the Southern Atlantic till it was within 

 sight of the tropics. The natural boundaries 

 of the Southern Ocean may be defined as a line 

 from Graham's Land to Tierra del Fuego ; from 

 Patagonia, across the shallowest belt of the 

 South Atlantic to Cape Colony ; thence, 

 approximately along the parallel of 36 S. lati- 

 tude to the south-western corner of Australia. 

 The Southern Ocean washes the whole southern 

 shore of Australia, and may fairly be extended 

 to include all the Tasman Sea. It runs down 



