86 Temperature Sections Surveyed. 



increase of less than i° C. in a distance of about 40° of latitude, 

 or 2400 nautical miles. 



Between Station 320 and Station 326, a distance of about 

 460 miles, we traverse the South Atlantic Equatorial Current, 

 forming a surface-stratum of an average depth of 50 fathoms, 

 with a temperature above 20° C. The undulating form of the 

 isotherms marks the struggle going on between the equatorial and 

 the polar current, betraying itself at the surface, as in the case 

 of the Gulf Stream or North Atlantic Equatorial Current, by the 

 formation of alternate streaks of warm and cold water. The 

 cold under-current which presses up at Station 324 and Station 

 329 comes to the surface at Station 326. The warm current 

 predominates at Stations 323, 325, 327 (at which latter station it 

 forms a warm surface-streak beyond the cold streak of Station 

 326), and 330. As far as Station 334 we trace the warming 

 influence of the equatorial current, a branch of which we have 

 seen (Plate 9) flows to the northward of Tristan d'Acunha 

 between the parallels of lat. 30° and 35° S. We have no 

 observations in a direct line between Cape Horn and the 

 Cape of Good Hope, but the main portion of the equatorial 

 current seems, after flowing in a southerly direction from the 

 place which it occupies in our section, to bend round between 

 the parallels of lat. 40° and 50° S., and, coming in conflict with 

 the Antarctic surface-current which flows towards the Cape of 

 Good Hope, to sink under it and continue its course into the 

 Antarctic regions as a warm under-current. The wide open 

 sea, discovered by Weddell in 1823 beyond the parallel of lat. 

 70° S. and in the meridian of South Georgia (long. 40° W.), is 

 probably an effect of this warm under-current. 



The low surface-temperatures between Station 135 and 

 Station 140 are due to the Antarctic surface-current which ? 

 flowing in a north-easterly direction, passes up in the space 

 between Tristan d'Acunha and the Cape. The rise of the 



