68 DISCOVERY REPORTS 



in its lower stratum is colder than that in the upper stratum of the North Atlantic 

 deep current which flows southwards below it. 



The current is probably not quite so strong in the eastern half of the ocean. The chart 

 in Fig. 1 6 and a comparison of the salinity distribution along section 7 (Plates X-XII) 

 with that along 30 W (Deacon, 1933, pi. viii) shows that the salinity of the current is 

 on the whole slightly greater, whilst its volume is smaller. A comparison of the sections 

 along the eastern and western Atlantic basins constructed by Wust (1928, pi. xxxiii), 

 and an examination of the cross-section in 35-4° S drawn by Moller (1926, pi. ii), leads 

 to the same conclusion. A small temperature inversion was found between the inter- 

 mediate and warm deep currents at each of the stations south of 30 S in section 7, but 

 it was much smaller than that found at Sts. 668-87 * n 3°° W. The weak nature of the 

 inversion in the eastern part of the Atlantic Ocean has also been noted by Wiist (1926, 

 p. 241). In the Rio Grande channel, the deep passage through the Rio Grande ridge 

 along the northern side of the Argentine Basin, he found that the inversion was as much 

 as 0-67° C, but in the east Atlantic Ocean he found an inversion only at the deepest 

 stations (75 and 77), where it was not more than 0-01-0-04° C. The greatest inversion 

 that we found in the eastern part of the ocean was 0-07° C. at Sts. 1172 and 1173. 



South-east of Cape Town (section 8, Plates XIII-XV), the northward movement in 

 the intermediate layer appears to be very small compared with the northward current 

 in the Atlantic Ocean ; the layer has both a small volume and a relatively high salinity. 

 Close to the south coast of the continent the minimum salinity almost disappears ; at 

 St. 425 (Station List, 1932) just off the continental shelf south-east of Port Elizabeth the 

 lowest salinity was probably not less than 34-6-34-7 °/ 00 . The only indications of a 

 temperature inversion in section 8 were found at St. 848 in 45 48' S, 27 14' E. 



East of 30 E the properties of the intermediate layer are illustrated by two sections 

 constructed by Moller (1929) — the Ceylon section running approximately north-east 

 from 45 S, 30 E to Ceylon and the Kerguelen section from Gaussberg to the Gulf of 

 Aden. In the southern part of the ocean they are based chiefly on the observations of 

 the 'Valdivia', 'Gauss', and 'Planet'. The salinity distributions along these sections 

 show that the intermediate current is stronger than it is in the region south of Africa, 

 but they also indicate that it has not such a large volume or low salinity as the Atlantic 

 current. The 34-30 °/ 00 isohaline which extends as far north as 28 S in the intermediate 

 layer in western part of the Atlantic Ocean is found about 8° farther south to the north 

 of Kerguelen. Both the Ceylon and Kerguelen sections indicate that there is a small 

 temperature inversion between the intermediate water and the highly saline deep water 

 in roughly 45 to 25 S°. 



The observations along section 9 (Plates XVI-XVIII) south-west of Cape Leeuwin, 

 the south-western extremity of Australia, point to the existence of a current of about 

 the same strength in the eastern part of the ocean ; the salinity of the layer is on the 

 whole slightly greater than it is in the Kerguelen section, but the volume of the current 

 appears to be roughly the same, and north of 45 ° S the increase of salinity towards the 

 north in the current is particularly small. 



