436 APPENDIX V 



Expedition in 1898 a station (No. 82) was taken in the Benguela 

 Current in the middle oi October, not far from the point at which 

 the Pram's Station 31 lay. The temperature curves from here 

 show that it was much warmer (over 1*5° C.) in 1898 than in 1911 

 in the zones between 500 and 800 metres (272 and 436 fathoms). 

 Probably the currents may vary considerably here. But in the 

 upper waters of the Benguela Current itself, from the surface down 

 to 150 metres, it was considerably warmer in 1911 than in 1898; 

 this difiference corresponds to that which we found in the previous 

 comparison of the Challenger^ s and Frames stations of 1876 and 

 1911. Between 200 and 400 metres (109 and 218 fathoms) there 

 was no difference between 1898 and 1911; nor was there at 1,000 

 metres (545 fathoms). 



In 1906 some investigations of the eastern part of the South 

 Atlantic were conducted by the Planet. In the middle of March a 

 station was taken (No. 25) not far from St. Helena and in the 

 neighbourhood of the Pram's Station 39, at the end of July, 1911. 

 Here, also, we find great variations; it was much warmer in 1911 

 than in 1906, apart from the winter cooling by vertical circulation 

 of the sub-surface waters. At a depth of only 100 metres (54 '5 

 fathoms) it was 2° C. warmer in 1911 than in 1906; at 400 metres 

 (218 fathoms) the difference was over 1°, and even at 800 metres 

 (436 fathoms) it was about 0'75° C. warmer in 1911 than in 1906. 

 At 1,000 metres (545 fathoms) the difference was only 0'3°. 



From the Planet's station we also have problems of salinity, 

 determined by modern methods. It appears that the salinities at 

 the Planet station, in any case to a depth of 400 metres, were 

 lower, and in part much lower, than those of the Pram Expedition. 

 At 100 metres the difference was even greater than 5 per mille; 

 this is a great deal in the same region of open sea. Now, it must 

 be remembered that the current in the neighbourhood of St. Helena 

 may be regarded as a continuation of the Benguela Current, which 

 comes from the south and has relatively low salinities. It looks, 

 therefore, as if there were yearly variations of salinity in these 



