SUB-ANTARCTIC WATER: SURFACE CURRENT 55 



fact that icebergs are not generally encountered north of a line 180 miles north of 

 Macquarie Island. Farther east, this line, which shows the usual limit of icebergs, bends 

 slightly northwards, running midway between the Campbell and Auckland Islands, and 

 cutting the 180th meridian in about 50 S (Antarctic Pilot, 1930, p. 19). In November 

 and December 1897, large numbers of icebergs were seen in 46 ° 3o'-5i° S between 

 175 and 165 W, evidently carried northward by the current which resembles the 

 Falkland current. Several large icebergs and loose ice were observed from the Chatham 

 Islands themselves in October 1892, but there appears to be no other record of ice being 

 sighted (New Zealand Pilot, 1930, p. 380). 



Observations made at Sts. 1277-81 (Appendix I) in the deeper water east of New 

 Zealand show that east of section 14 the isotherms and isohalines bend sharply south- 

 wards. The high temperatures and salinities, belonging to a southward movement of 

 subtropical water, seem to be definitely associated with the deep soundings, and the 

 poorly saline water, belonging to the northward sub-Antarctic current, with the com- 

 paratively shallow ones. Schott (1934, p. 241) has emphasized the great difference of 

 salinity between the waters east of South and North Islands ; and to the east of North 

 Island, where the water is much warmer and more saline, the soundings are also much 

 greater. The preliminary chart drawn by Merz (Wiist, 1929, p. 41) gives, however, 

 only weak indications of a southward current, and although the general northern limit of 

 icebergs (Admiralty Chart, No. 1241, 1910) bends slightly southwards between\i8o and 

 150 W the bend is not large enough to be used as evidence of a southward movement. 



In the eastern half of the Pacific Ocean the movements of sub-Antarctic water are also 

 rather uncertain. The isotherms are almost parallel to the lines of latitude until very close 

 to the west coast of South America, where they branch towards the north and south. 

 The temperature distribution seems to suggest that the main drift across the Pacific is 

 directed towards the east, but that it divides off the coast of Chile, in about 44 S, into 

 a southward current towards Cape Horn and a northward current along the coasts of 

 Chile and Peru towards the Galapagos Islands. 



The salinity distribution indicates, however, that the water in the northernmost part 

 of the zone flows towards the west. In the central part of the ocean (sections 15 and 16, 

 Plates XXXIV-XXXIX) the salinity of the surface water does not increase towards the 

 north as it does in the Atlantic, Indian, and West Pacific Oceans; after rising to a 

 maximum of just over 34-4 °/ 00 in 50 S it decreases to 34-14 °/ 00 in 41 S. The same 

 low salinity was found in this region by the 'Challenger' at St. 289, the actual value, 

 calculated by Wiist (1929, p. 59) from the density measurements, being 34-18-34-25 °/ 00 - 

 Schott (1928, pi. xiv) and (1934, pi. i) has shown that this area of low salinity is part 

 of a tongue of poorly saline water which extends towards the west from a poorly saline 

 coastal region, south of 35 S, west of Chile. Wiist (1929, p. 42) also concludes that 

 the poorly saline water at Challenger St. 289 has its origin in about 40 S in the eastern 

 part of the ocean, and it can only be supposed that the sub-Antarctic water in the 

 neighbourhood of 40 S flows towards the west. The preliminary current chart by Merz 

 shows that the northward current along the west coast of Chile turns back towards the 



