2O THE CLIMATE OF AUSTRALASIA 



troughs, separated by the plateau that runs 

 southward down the central line of the Atlantic. 

 South of Cape Colony was shewn another 

 trough, from 2000 to 3000 fathoms deep, con- 

 necting the deep basin of the eastern Atlantic 

 with the main basin of the Indian Ocean. This 

 deep water, south of the Cape, was thought to 

 be driven to the north by the projection of the 

 Kerguelen plateau, extending from the Ant- 

 arctic to north of latitude 40. The platform 

 on the southern border of the Atlantic and 

 Indian Oceans was regarded as an extension of 

 the Antarctic plateau ; while the deep troughs 

 of the South Atlantic and Indian Ocean are the 

 channels by which the cold water, which chills 

 the deeper waters of the great oceans, flows 

 slowly northward from the Antarctic. 



The Southern Ocean was supposed to shallow 

 steadily southward to the Antarctic lands, 

 and the Indian Ocean was charted as one great 

 basin of unbroken depth. But the work of the 

 last five years has changed most of that. The 

 German deep-sea exploring ship, the Valdivia, 

 found deep water in the Antarctic, where it 

 expected to find shallow ; and it found shallow 

 water in the Indian Ocean, where it expected 

 to find deep. The view that the Antarctic 

 continent sloped gradually northward was 

 founded on little direct knowledge. Up till 

 1898 only 15 reliable deep sea soundings had 

 been made south of 50 S. The Valdivia 

 expedition added 29, which showed that the old 

 conception was erroneous. 



