OCEANOGRAPHY 



409 



But the cause or causes of these variations in the Gulf Stream are 

 at present unknown. In order to solve this diflScult question we must 

 be acquainted with the conditions in those regions of the Atlantic 

 itself through which this mighty ocean current flows, before it sends 

 its waters into the Norwegian Sea. But here we are met by the 

 difficulty that the investigations that have been made hitherto are 

 extremely inadequate and deficient; indeed, we have no accurate 



'Fig. 1. — Hypothetical Representation of the Surface Currents in 

 THE Northern Atlantic in April. 



After Nansen, in the Internationale Revue der gesamten Hydrohiologie und 



Hydrographie, 1912. 



knowledge even of the course and extent of the current in this 

 ocean. A thorough investigation of it with the improved methods 

 of our time is therefore an inevitable necessity. 



As the Gulf Stream is of so great importance to Northern 

 Europe in general, but especially to us Norwegians, it was not a 

 mere accident that three separate expeditions left Norway in the 

 same year, 1910 — Murray and Hjort's expedition in the Michael 

 Sars, Amundsen's trial trip in the Fram, and Nansen's voyage in 



VOL. II. 52 



