240 



DEPARTME^^T OF THE NAVAL SERVICE 



From the Archimedean forces, therefore, we can calculate the centrifugal forces, 

 and thus arrive at the transposition of the water. This ingenious method of cal- 

 culating the movements of sea water will be employed in the following, when dealing 

 with the Newfoundland area. 



A contrasted distribution of density arises when the surface water circulates 

 anticyclonically, as is the case in the horse latitvides. Here, the deep water rotates, 

 as a matter of fact, with the Atlantic basin; the surface water, however, moving at 

 a slower rate. The centrifugal force of the deep water is therefore greater than that 

 of the surface water, and the former is consequently flung out more strongly than 

 the latter. The result of this, again, is that the surface water keeps to the centrej 

 of the area (vide fig. 24 B), and this warm upper layer therefore reaches down at 

 this point to a depth of 600 metres, whereas at the equator, its depth is only 200 

 metres. 



Now, as we know, the diagram of velocity for a vertical line through a sea cur- 

 rent assumes, owing to friction, the form of a parabola, the velocity being at its 

 maximum a little below the surface of the sea. In the lower portions of the current 

 it decreases greatly with increasing depth. When, therefore, the surface water in 

 a basin circulates cyclonically, as before described, the cyclonic circulation and the 



B 



Fig. 23. — Scrowiiip- movement of surface wiiter 

 in cvclonif circulation. 



centrifugal force will reach their maximum near the surface of the sea, decreasing 

 rapidly with increasing depth. And the actual surface water will be flimg out more 

 strongly than the water in the lower portions of the surface layer. The effect of 

 this is that the former moves toward land, and the latter out to sea (vide fig 23 B). 



