CH. Il] THE OCEANOGRAPHY OF THE NORTH-WESTERN OCEAN 49 



It will be seen from the chart of the North-Atlantic ocea,n 

 that a deep depression lies just off the coasts of Norway and 

 Sweden. This leads into the Skagerak. The Atlantic water 

 coming round the north of Scotland Hows into this channel and 

 becomes banked up there by the shoaling of the bottom. As 

 summer advances this water becomes covered up by lighter and 

 warmer water, so that at the bottom the temperature is from 4^ to 

 7° C, while on the surface the temperature is about 16° C. In the 

 February following, while this bottom water still retains its heat, 

 the surface has cooled down to 2° to .S"" C. An undercurrent 

 from this heaped-up bottom stratum then enters the Baltic, where 

 it produces momentous effects on the course of the fisheries. 



Finally the Norwegian Branch of the European stream reaches 

 as far as the remote waters of the Barentz Sea, and enters that area 

 as the so-called North Cape current. " The geographical position 

 of the North Cape current and its ramifications is constant, quite 

 as constant as is that of our rivers ^" 



Annually the Barentz Sea is invaded by a heat wave which is 

 the result of the increase in the volume of the Atlantic water 

 which enters it. The summer of the sea is November ; its winter 

 is June. In the latter month the temperature of the bottom 

 layer is T C, in November it is 5^ C. or more. This increase in 

 temperature is due to the increased flow of the Atlantic stream, 

 which attains its maximum in the latter month. In the Barentz 

 Sea the stream has cooled down so that it now flows on as an 

 undercurrent. With the Atlantic flow fishes like the cod and 

 haddock invade the Barentz Sea. In November the stream of 

 genia] water begins to decrease and cold Arctic water takes its 

 place. With this change the fisheries cease. 



We see then that there are three principal factors in the 

 circulation of the water of the North-Atlantic Ocean. There is 

 first the European Stream which flows up from the Atlantic 

 Ocean south-west of the British Islands. Then we have a much 

 smaller stream of cold water which flows down from the Arctic as 

 the East-Icelandic Polar Stream and which may at times enter the 

 Faeroe Channel and obstruct the flow of the European Stream. 



^ Breitfuss, " Oceanographische Studien liber das Barentz ^leer,''' Petennann^s. 

 Mitth. 1904. 



J. F. 4 



