1145 & 
of the same kind; a minimum in spring, a corresponding maximum 
in autumn. 
To explain the phenomenon, whose generality has become known 
only of late years, different ways have been tried. 
In the supposition that it was limited to the southern part of the 
North-Sea and the Baltic and thinking the wind responsible for the 
periodical fluctuations VAN DER STOK comes to the following conclusion. *) 
“A comparison of these (wind) results with those, indicating the 
periodical and non-periodical fluctuation of the sealevel shows, that 
— though some correspondency as the distinet November-minima 
cannot be denied — a real connection fails. Neither the April-minimum, 
nor the Oetober-maximum can be explained as a result of the wind 
on our coast. 
A more accurate investigation of the fluctuations in the waterlevel 
as well as of those in the windsystem both on the Duteh coast and 
the whole North-Sea is desirable.” 
GEELMUYDEN says: 
“The yearly fluctuation is very marked along the whole Norwegian 
coast; 1 think an explanation must be looked for in periodical 
changes of pressure and wind.” | 
In Prrrerson’s work the following quotation is to be found: 
“Tf on the other hand, only Dutch observations had been acces- 
sible, the inferences drawn from them would certainly have pointed 
to the wind as the originator of the fluctuations. Now, since a 
comparison of facts has shown the analogy of the fluctuations in 
the North-sea, the Baltic and the Kattegat, such inferior explanations 
are excluded, and we must acknowledge the fluctuations to be the 
outcome of a general pulsation of the ocean from the tropics to the 
Polar Sea. The pulsation of the northern seas is analogous with that 
of the Atlantic.” 
Speaking about the North-Atlantic Current it is evident he considers 
that stream not to be a direct offshoot of the Gulfstream, an opinion 
hot generally shared. 
Wirrtnc after having pointed out the correspondency of phenomena 
in North-Sea and Baltic, tries to find an explanation in fluctuations 
in the quantity of water in these seas. In his opinion these fluctuations 
are caused by the wind, however not by the wind in the North-Sea 
or in the Baltic, but so far as the Baltic is concerned by the wind 
near its gates; the Skager Rak, the Belts and the Kattegat. 
Breitrusz found from serial-observations in latitude 71° N. and 
dte pe 20. 
