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SCIENCE PROGRESS 



Now fig. 2 shows that the water which passes through the 

 Faeroe-Iceland Channel also passes over the Sognefjord line, 

 and then over the Lofoten line and so into the Barentz Sea. 

 But large masses of sea-water change in temperature and 

 salinity very slowly, and we should expect to find that the 

 periodicity which is indicated above would also be shown in 

 the more northerly hydrographic sections. But if we plot 

 series of values obtained in this way on the same diagram, 

 superposing the data for the same years, nothing but confusion 

 appears to result. If, however, maximum and minimum be 

 superposed on each other it is at once seen that the periodicity 



Fig. 3. — Sea-temperatures, etc., in the Norwegian Sea. 



Curve I. The average temperature of the Atlantic water beneath the surface at the Sognefjord section. 

 ,, II. The same for the Lofoten section. 



,, III. Average sea-temperatures at depths from 100 to 200 metres in the Barentz Sea. 

 ,, IV. The area of ice-free sea-surface in the Barentz Sea. The values are io' kilometres 2 . 

 All curves represent the conditions in May. (From Helland-Hansen and Nansen, loc. cit. p. 344-) 



is the same. This has been done in the above diagram, 

 prepared by Helland-Hansen and Nansen. Curve I. shows 

 the average temperature of the sea beneath the Sognefjord 

 section, II. the same for the Lofoten section, and III. the same 

 for three Russian stations in the Barentz Sea. Curve IV. 

 shows the area of ice-free sea-surface in the Barentz in hundreds 

 of thousands of square kilometres. 



Now, there can be no doubt that the nature of the physical 

 changes in the sea in each of these regions is the same, and 



