422 ' APPENDIX V 



Between the two long lines of section there is a distance of 

 between ten and fifteen degrees of latitude. There is, therefore, 

 a considerable difference in temperature. In the southern section 

 the average surface temperature at Stations 1 to 26 (June 17 to 

 July 17) was 17'9° C; in the northern section at Stations 36 to 60 

 (July 26 to August 19) it was 21 '6° C. There was thus a differ- 

 ence of 3*7° C. If all the stations had been taken simultaneously, 

 the difference would have been somewhat greater; the northern 

 section was, of course, taken later in the winter, and the tempera- 

 tures were therefore proportionally lower than in the southern 

 section. The difference corresponds fairly accurately with that 

 which Kriimmel has calculated from previous observations. 



We must now look at the conditions below the surface in that 

 part of the South Atlantic which was investigated by the Fram 

 Expedition. 



The observations show in the first place that both temperatures 

 and salinities at every one of the stations give the same values 

 from the surface downward to somewhere between 75 and 

 150 metres (40'8 and 81 '7 fathoms). This equalization of tem- 

 perature and salinity is due to the vertical currents produced 

 by cooling in winter; we shall return to it later. But below these 

 depths the temperatures and salinities decrease rather rapidly for 

 some distance. 



The conditions of temperature at 400 metres (218 fathoms) 

 below the surface are shown in the next little chart. This chart 

 is based on the Fram Expedition, and, as regards the other parts 

 of the ocean, on Schott's comparison of the results of previous 

 expeditions. It will be seen that the Frames observations 

 agree very well with previous soundings, but are much more 

 detailed. 



The chart shows clearly that it is much warmer at 400 metres 

 (218 fathoms) in the central part of the South Atlantic than 

 either farther north — nearer the Equator — or farther south. On 

 the Equator there is a fairly large area where the temperature 



