102 DISCOVERY REPORTS 



saline waters in the shallower and deeper strata. The deep channel between the new 

 Zealand shelf, which extends as far south as the Campbell and Auckland Islands, and 

 the Antarctic shelf, is less than iooo miles wide, and it is obstructed by several shallow 

 banks and islands. A preliminary examination of our soundings along sections 12 and 

 13 suggests that the bottom topography is even more rugged than has hitherto been 

 supposed. 



Further observations made east of New Zealand in the deeper soundings to the east 

 of section 14 (Sts. 1277-81, Appendix I) showed that the salinity of the deep water may 

 be as much as 34*78 °/ 00 , but no simultaneous observations were made in the region 

 south of Australia. The data as a whole are not conclusive, but they give a weak indica- 

 tion that water east of New Zealand is slightly more saline than that which enters the 

 Pacific Ocean south of New Zealand. Before the difference can have much significance, 

 however, it must be confirmed, and more information must be obtained of the possible 

 fluctuations in the salinity of the eastward current due to changes in the deep water 

 circulation of the Indian Ocean (see p. 97), but its likelihood suggests that there is still 

 a possibility of a small highly saline current from another source, such as one of those 

 suggested by Wiist — sinking of the surface water in some partly enclosed basin in the 

 subtropical regions, or in the coastal region east of the northern part of Australia. The 

 salinity, temperature, and oxygen distributions in section 14 suggest that the principal 

 movement in the highly saline stratum east of New Zealand is towards the north, but 

 they do not preclude the possibility of a small southward movement of highly saline 

 water with a low oxygen content in the upper part of the highly saline stratum. 



The data from the southern part of the Pacific Ocean as a whole (sections 14-18) suggest 

 that the highly saline water in the Antarctic Zone spreads towards the east, and also, as a 

 bottom current, towards the north. Above this bottom current and below the northward 

 current in the intermediate layer there is, however, evidence of a stratum of deep water 

 whose high temperature and low oxygen content, combined with a salinity greater than 

 that of the intermediate water, suggest that it flows southwards ; its movement appears 

 to be almost horizontal until it approaches the Antarctic Zone where it climbs towards 

 the surface, steeply in the west and gradually in the east; it then flows almost hori- 

 zontally again, in the upper stratum of the deep layer, as far as the continental slope. 

 The properties of the water in the current suggest that it is formed chiefly in the 

 equatorial region by the mixing of the highly saline water carried northwards by the 

 bottom current with the warmer but less saline waters of the Arctic and Antarctic inter- 

 mediate currents. The difference between its properties and those of the intermediate 

 and bottom waters is the strongest indication that it flows southwards, and the signs of 

 a temperature inversion between the intermediate water and the deep water found by 

 Wiist (see p. 100), and the need for a compensation current to balance the northward 

 movements in the intermediate and bottom layers are good arguments in favour of the 

 same movement. 



The high temperature of the deep water in the eastern part of the Antarctic Zone and 

 the increase in the temperature of the deep layer towards the east from the region south- 



