GENERAL BIOLOGY 



695 



is situated in the Sargasso Sea, Station 86 on our northern 

 track, Station loi to the south of, and Station 113 to the north 

 of, the Wyville Thomson Ridge, while Station 46 from the 

 year 1900 is west of the Lofotens. 



Figs. 504 and 505 show that just on the verge between 

 the two seas, between Stations loi and 113, a marked drop 

 occurs in the temperature and specific gravity. In the Nor- 

 wegian Sea (Station 46 of 1900) a specific gravity of 1.0278 is 



St.6d 



too 



66 



101 



115 



46 





i — • 



y 



/^ 



/ 



/ 



1500 



Fig. 505.— Distribution of Specific Gravity from the Sargasso Sea (Station 63) 



TO Lofoten (Norwegian Sea). 



28 = 1.028. 



found only at 100 metres, and towards the Wyville Thomson 

 Ridge even at 1500 metres. A specific gravity of 1.028 does 

 not occur in the Atlantic at all at the depths here treated of, 

 while the entire deep layer in the Norwegian Sea is of a 

 specific gravity even higher than 1.028. In the Atlantic the 

 curves all fall away towards deep water and as we approach the 

 tropics. In the Sargasso Sea we find the same specific gravity 

 at 600 or 800 metres as occurs in the Norwegian Sea at 50 

 metres. The densely gathered curves at the surface denote 

 water of low specific gravity. 



