404 T. C. CHAM BERLIN 



tion of the salinity of the whole ocean which, in the long run, must 

 be preserved. All our postulates seem thus to tend to general 

 equilibrium and at the same time recognize the excess of evapora- 

 tion over precipitation in the North Atlantic drainage area taken as 

 a whole. 



THE APPLICATION OF THE FOREGOING TO THE SPECIAL 

 CASE IN HAND 



The purpose of the foregoing rather wide-ranging discussion 

 is to bring out the general features of circulation from which the 

 ameliorating current of Baihn Bay is derived by a natural rather 

 than a strained hypothesis. In itself, the Baffin Bay branch is a 

 small affair, but its peculiarities make it refractory to the usual line 

 of interpretation. It is hence suggestive and significant. As a 

 feature of the "Gulf Stream" or of the northeasterly "drift of the 

 Atlantic" surface waters as ordinarily understood, the locaHzation 

 of the warm Baffin Bay current diverges from ordinary oceanic 

 modes of movement. Its line of projection is northwestward from 

 the center of generation of the warmth and salinity it carries pole- 

 ward, while the normal direction due to the influence of the earth's 

 rotation is northeastward. Yet the rotational influence is as obvi- 

 ous on this current as on others, after it has entered Baffin Bay. 

 The rotational effect is of course always active, but in the massive 

 movement of the deeper part of the middle layer of the Atlantic 

 Basin it is overcome by co-operating influences now to be noted. 

 As a slow undercurrent in the embrace of currents of different trend 

 above and below, and as a mere offshoot from the great middle layer 

 of the Atlantic column, its explanation takes on a special phase 

 dependent on these conditions. In the region where it is generated, 

 the middle Atlantic layer is 2,000 meters thick, less the depth of the 

 Greater Gulf Stream that floats above it. The true Gulf Stream, 

 as it is crowded through the Florida Straits, is credited with a depth 

 less than a third of this, and as it spreads out in the higher latitudes 

 its depth is undoubtedly still less. The middle layer, as here inter- 

 preted, thus extends much below the crest of the weir formed by the 

 Southern Intercontinental Ridge. This ridge stands obliquely 

 athwart the natural line of northeastward flow of the warm middle 



