RECENT HYDROBIOLOGICAL INVESTIGATIONS 479 



the strong tidal streams, and are oscillatory ones, the water 

 surging backwards and forwards along, or at an angle to the 



•T\A^ 



Polar 

 S t re am 



Spitsbergen . / 



LI* frv 



wtttu 



C^ A nnt 



vttttt 



}ttft / 



Gulf Stream 



Fig. 2. — The Gulf Stream drift in high northern latitudes. 



The arrows indicate the direction of drift of the surface waters. The crowding together of the arrows is 

 roughly proportional to the intensity of flow. (From Helland-Hansen and Nansen, " The Norwegian 

 Sea," Report on Norwegian Fishery and Marine Investigations, vol ii. part i. Bergen, 1909.) 



land. The flow ol water due to the Atlantic drifts may only 

 be detected by very precise current-measurements, and as 



