gS SECTIONAL ADDRESSES 



Vladivostok, though it is ice-bound each winter, lies in the same 

 latitude as Marseilles. This is only one of many facts which impresses 

 us with the climatic advantages that we derive from the warm water 

 of the Atlantic drift, and it might be thought that an investigation of 

 the causes which underlie this phenomenon would long since have been 

 undertaken by those who reap such great benefit. Yet, to the present day, 

 these problems remain unsolved and, as Dr. Iselin has recently shown, '^^ 

 three mutually conflicting theories are extant regarding the circulation 

 of water in the North Atlantic. 



Fortunately there are signs that a period will be set to our ignorance. 

 On the American side of the Atlantic the Woods Hole Oceanographic 

 Institution is making a study of the Gulf Stream and of the effect of wind 

 velocity and direction on the strength of a current. There is to be 

 British co-operation in this programme, based on the Bermuda Biological 

 Station. The Royal Society is administering a Government grant which 

 has been given for the purpose, and additional staff for the Bermuda 

 station and a small research ship have been provided. Data recently 

 obtained by the Woods Hole Institution show that the transport of water 

 in the Gulf Stream has varied by as much as 20 per cent, in fourteen 

 months, and it may well be that this figure is below the normal range of 

 variation. When the observations over the five-year period which is 

 contemplated have been carried out we may hope to know far more than 

 we do at present of the Gulf Stream and its effects on circulation in the 

 North Atlantic. 



During the present year a German research ship is making a prolonged 

 investigation of the hydrography of the North Atlantic, and only two 

 months ago research ships from Denmark, Norway and Scotland were 

 co-operating with her in studying extensive areas from the Azores to 

 Iceland. 



From such combined attack we shall learn much and there is every 

 reason to believe that the main features of the circulation in the North 

 Atlantic will shortly be understood. But though we may look for results 

 of the highest importance from these investigations it is evident that they 

 will not solve the biological problems with which we are faced ; for the 

 work in the eastern Atlantic is an isolated set of observations, most 

 valuable as a contribution to our knowledge of the general conditions, but 

 affording little help in solving the problem of long-period faunistic fluctua- 

 tions of which I have spoken. It is the deviations from the normal 

 which are of paramount importance to the biologist, and it is only by 

 repeated observations made over a series of years that they can be detected. 



To make such observations at sufficiently close intervals of time and 

 space over the whole of the north-east Atlantic is clearly not within the 

 bounds of present possibility ; but when we have gained an adequate 

 knowledge of the normal system of circulation it is to be expected that 

 certain critical positions or regions will be discovered, and that regular 

 data from those places will give information from which the variation in 

 the whole system can be deduced. Even such a programme as this is 

 far beyond the resources we now possess ; but I believe that the need for 



'^ C. O'D. Iselin, ' Problems in the Oceanography of the North Atlantic,' 

 Nature, vol. 141, p. 772 (1938). 



