SECTIONAL TRANSACTIONS.—D. 325 
physical and chemical data pertaining to sea water in situ. The most 
fundamental property of the sea is its constant and more or less complex 
motion, to which all questions concerning the sea itself, or its inhabitants, 
must sooner or later be referred. 
Horizontal movements, or currents, particularly those in the upper sea 
layers, are the most obvious and, generally speaking, are of the first import- 
ance from a biological point of view. ‘Their measurement in the northern 
North Sea by the drift-bottle method has produced some striking results, 
both in regard to direction and velocity. ‘These results have proved of 
value in the interpretation of adolescent and adult fish migrations in this 
region. Biologically they are significant also from the standpoint of plankton 
and young fish movements. 
Dr. J. N. CarRuTHERS.—Certain fishery applications of the results of 
researches on marine currents carried out from the Lowestoft 
Fisheries Laboratory. 
An account was given of continuous current measuring observations 
carried out from the Varne lightship in Dover Straits. From this moored 
vessel a current-meter has been employed for eight years, and data regarding 
the water exchange between English Channel and North Sea have been 
amassed over that period. The varying water movements there observed, 
when balanced out over a term of years, have effected the same overall 
transport of water as would have been accomplished by a very slow river 
flowing at the rate of about 31 miles a day from the English Channel to 
the North Sea. Under certain circumstances the current flows the other 
way. Following winds quicken it and head winds impede it. A play of 
such wind conditions over the North Sea at large as would be expected to 
pool up the Southern Bight (and north-westerly wind conditions are well 
known to do this) can most effectively hold up and reverse the current. 
The results of the last three years are of especial interest, for, instead of 
the residual current heading boldly into the North Sea (as it most frequently 
had done in the previous three years) it has displayed less and less easting 
with the passage of time. During 1933 the current headed about half a 
point west of north. 
Such long-enduring modifications of the current are held to be analogous 
in a way to the short-lived modifications produced by wind influence. 
The inferred cause in their case, however, is an oceanic pulse—an accession 
of strength on the part of the parent supply stream which flows in from the 
ocean round the north of Scotland. This causes an extra strong southward 
urge of waters through the North Sea—with the results observed in 1933 
particularly. 
The Dover Straits current attains its strongest and weakest rates of flow 
half a year later than does the current entering the North Sea round the 
north of Scotland, but a quarter-year later than the current in the Cromer 
Knoll region. 
These facts are interpreted to indicate that the Dover Straits current 
waxes and wanes through the year in a sort of buffer relationship with the 
current from the north—that there exists a sort of see-saw conflict between 
the two. 
The vagaries of the Dover Straits currents, on the strength of the findings 
mentioned, are held to serve as pointers to major modifications of the currents 
in the northern and middle reaches of the North Sea half a year earlier. 
The results obtained from the current measurements in question have 
been applied to various problems of fishery interest. Among problems of 
