From Stat mi 288 to Magellan Straits. 121 



A more simple explanation of this counter-current may be 

 found in the fact that the equatorial currents, as they flow on 

 each side of the belt of calms, remove the water from the 

 eastern and accumulate it at the western side of the basin, and 

 that the counter-current tends to restore the equilibrium thus 

 constantly disturbed. 



Section from Station 288 to Valparaiso and Magellan 

 Straits (Plate 20, Table XIV.). — This section may be compared 

 with the soundings between Tristan d' Acunha and the Cape of 

 Good Hope (Plate 11). It extends for the greater part along 

 the parallel of lat. 40° S. between the meridians of Pitcairn 

 Island and Juan Fernandez, and coincides with the limit 

 between the thermal areas of the South Pacific and of the 

 Southern Ocean. With rapidly-decreasing temperatures in the 

 surface-stratum between lat. 30° and 40" S., we arrive, at Station 



288 on the 40th parallel with a surface-temperature of i2°.5 C, 

 and the isotherm of 10° C, at a depth of 95 fathoms. Proceeding 

 eastward, we observe a sudden rise of the latter isotherm from 

 95 fathoms to 45 fathoms at Station 288, and to 40 fathoms at 

 Station 290, gradually falling to 90 fathoms at Station 294, 

 indicating a cold surface-current from the south between Stations 



289 and 292. The increase of temperature further eastward 

 between the surface and 100 fathoms, combined with the lessen- 

 ing latitude of the stations, shows that we enter more and more 

 into the warmer water of the equatorial return-current which flows 

 over the plateau of Juan Fernandez (Plate 5), especially percep- 

 tible at Station 296 ; while the sinking down of the isotherm of 

 2°.5 C. between Stations 292 and 296 attests the presence of a 

 warm under-current, which, flowing along the southern slope of 

 the plateau, turns southward towards the Antarctic shores of 

 Graham Land. Part of this current is probably carried through 

 the Strait of Cape Hoorn. On the other hand, the rise of the 

 isotherms of 2°. 5, 5°, and 10° C. at Stations 297, 301, 302, and 



