"deep-current" is concerned. In his revised theory of 193 2 , the 

 dynamical theory of the wind driven ocean circulation and its 

 problems were developed by Ekman to such a degree of completeness, 

 that relatively few additions have been made since that time. Prob- 

 ably, the only point where Ekman 's model of steady state ocean 

 currents has been revised essentially, and where in the future 

 essential revisions have to be expected, is concerned with the 

 mechanism and the effect of internal friction and vertical density 

 stratification. 



A new epoch of theoretical research in the field of wind 

 induced ocean currents started with the work by H.U. Sverdrup 

 (1947), H. Stomrael (1948), K. Hidaka (1949) and W. Munk (1950). 

 These authors essentially gave up trying to evaluate the vertical 

 velocity distribution and confined the analysis to the horizontal 

 mass transport by introducing the vertically integrated mass trans- 

 port as the dependent variable. This was necessary in order to 

 avoid certain difficulties which rendered Ekman's analysis too 

 complicated. It was possible to examine the more general case of 

 a baroclinic ocean without having to specify the nature of the 

 vertical distributions of density and currents, although even in 

 this case, some simplifying assumptions had to be made. The prob- 

 lem was to derive the gross features of the horizontal mass trans- 

 port of the oceanic circulation for a given wind system. These 

 stimulating theories can be considered as a remarkable step in 

 dynamic oceanography, and the results obtained by the various models 

 are of great interest. 



H. Stommel succeeded in 1948 in showing that due to the effect 



