102 Hydrographical Observations, North. Atlantic, 1903 and 1904 



V. connect up points on the other lines with Station 53, the chief 

 station on Section III. at which samples were taken. 



Perhaps the most striking result of the minute study of special 

 l^arts of the sea which has been made during recent years is the recog- 

 nition of the wide range of variation in the movements of waters from 

 season to season and from } r ear to year. It has been shown that not 

 only in enclosed areas like the North Sea, where varying land influences 

 are important, but in the open ocean itself, the currents are constantly 

 changing in direction and speed of movement, and the same parts of 

 the ocean are occupied at different times by water derived from widely 

 different sources. 



An immediate consequence of this discovery is that the problems 

 of oceanography are vastly more difficult of complete solution than 

 was supposed. It is now practically impossible to draw general 

 conclusions as to the circulation in a given area from one set of 

 observations, however complete ; the records must extend over a 

 number of years, and include different seasons of the year precisely as 

 in meteorology. 



Under these circumstances it seems useless to attempt a general 

 discussion of Dr. Wolfenden's observations. They form a very 

 valuable contribution, probably the most valuable ever made by a 

 private individual, at least in this country, to the steadily increasing 

 amount of material ; but the discussion of the 1903 observations really 

 involves the whole question which it is one of the main objects of the 

 International Council to elucidate, and the 1904 observations refer to 

 an area about which we have not as yet anything like as much 

 information as we have about the Faeroe- Shetland Channel. It is 

 permissible, however, to state shortly the main features of the dis- 

 tributions shown by the sections, and to compare them where possible 

 with those of other years. 



1903. — The sections enumerated above, and the sections ' Faeroe- 

 Shetland,' I. and II., for the same period, published by the Inter- 

 national Council, suggest that the events of 1902 are being repeated, 



