60 A TEXTBOOK OF OCEANOGRAPHY 



of the North-Sea, the Skager-Rack, the Norwegian Sea, and 

 even Barents Sea, with water of Atlantic origin. 



The oceanic circulation in these waiers is unquestionably 

 dependent on the pulsations of the Gulf Stream. There is a 

 continual drift of relatively warm and dense water from the 

 south-west towards Northern Europe. 



The following chart (Fig. 9) shows the observed conditions 

 prior to the commencement of the international investigations 

 (for August, 1896). 



The chart shows what is probably the maximum flooding 

 of the North Atlantic water by the Gulf Stream drift. The 

 current has invaded the Icelandic coastal region, and has 

 penetrated into Denmark Strait between Iceland and Green- 

 land. Flowing on to the western coasts of the British Isles, 

 the stream divides, part passing through the English Channel 

 into the North Sea. The main stream passes on through the 

 Iceland-Faroe and the Faroe-Shetland Channels. The inter- 

 national investigations, however, prove that not much Atlantic 

 water passes through the former channel (Fig. 40). The whole 

 of the oceanic basin south of the Iceland-Scotland ridge is 

 filled with Atlantic water. When this warm and dense water 

 impinges on the ridge only the surface portion of it passes over 

 into the Norwegian Sea. After passing over this ridge, the 

 ' Norwegian branch of the European current " is deflected to 

 the east, and a branch rounds the north of Scotland and enters 

 the North Sea (Fig. 9). 



Endeavours have been made to correlate the variations in 

 temperature and salinity with the pulsations of the Gulf Stream 

 drift, and as a consequence with the climatic variations of 

 Western Europe and the distribution and migrations of com- 

 mercially valuable species of fish, such as the herring and 

 plaice. 



It is manifestly impossible to give even in outline a 

 summary of this important scheme of hydrographic research, 

 and reference is made here only to the investigations in the 

 Irish Sea area, it being understood that similar, or even more 



