54 DISCOVERY REPORTS 



South of Tasmania and New Zealand the isotherms and isohalines suggest that the 

 current is deflected southwards. They are, however, very irregular and indicate that the 

 current becomes involved in a large number of small eddies which can almost certainly 

 be attributed to the influence of the exceptionally rugged bottom topography of the 

 region. 



On reaching the west coast of New Zealand the current divides into two branches, 

 one flowing towards the north and the other towards the south. The current does not 

 divide on the south-western extremity of South Island in 46 S, but a little farther north 

 near Jackson Bay in 44 ° S ; between these two points the current sets almost constantly 

 southwards (New Zealand Pilot, pp. 29-30). Along the east coast of South Island 

 the current also runs north-eastward, and farther south, past Auckland and Campbell 

 Islands, towards the east. 



The temperature and salinity distribution east of New Zealand indicates that the north- 

 ward current is not confined to the coastal region but extends as far off-shore as the 

 Antipodes and Chatham Islands ; the width of the current is probably related to the 

 soundings, since it appears to be confined to a region in which the depth is 2000 m. or 

 less, and is replaced by a southward current where the depth increases suddenly to more 

 than 5000 m. just to the east of the Chatham Islands. In section 14 (Plates XXXI-XXXI II) 

 across this region the coldest water was found at Sts. 944 and 946 near the eastern 

 limit of the shallow soundings. This is possibly an indication that the northward move- 

 ment is strongest there, but it may also be an indication of upwelling between the 

 northward current in the shallow water and a southward current in the deep water 

 farther east. The existence of the southward current was shown by the observations 

 given in Appendix I, which reveal a sharp bend of the isotherms and isohalines towards 

 the south in the deep water. 



The movements of sub-Antarctic water in the neighbourhood of New Zealand show 

 on the whole a close resemblance to those east and west of South America. As the West 

 Wind Drift approaches the west coast of South Island, it divides into two branches 

 just as it does off the west coast of Chile. Off each coast the division takes place in 

 about 44 S, and one branch flows northwards whilst the other turns to the south. 

 In each region also, the southward current flows towards the east round the southern 

 extremity of the land, and, joined by more water from the main easterly drift, turns 

 northwards along the east coast. The northward current east of New Zealand has 

 therefore a great similarity to the Falkland current. It is, however, on a smaller scale, 

 and has a higher temperature and salinity, but these differences would be expected 

 owing to the much shorter distance to which New Zealand projects into the path of 

 the easterly drift. 



The analogy between the two currents is heightened by the fact that in the deep water 

 east of New Zealand, there are indications of a southward current of warm and highly 

 saline subtropical water with some resemblance to the Brazil current. 



The deflection of the West Wind Drift towards the south as it crosses the region south 

 of the Tasman Sea and approaches New Zealand affords a reasonable explanation of the 



