34 THE OCEAN. [Book II. 



that exemplified in Plate Y. And, since the de- 

 flection of westward pressure by coast-lines must 

 cause an overwhelming of the lesser forces of the 

 polar regions by the greater force of the equatorial 

 regions, there must therefore, in every ocean, be a 

 combination of these two systems of circulation. 

 That is to say, there must be a horizontal circula- 

 tion resulting from the overwhelming of the forces of 

 the polar regions by the force of the equatorial re- 

 gions ; and also a vertical circulation resulting from 

 the overwhelming of the force of the lower strata by 

 the force of the upper strata. As the one system 

 tends to cause each district to rotate round a vertical 

 axis, and the other system tends to cause it to rotate 

 round a horizontal axis, their combined action must 

 cause it to rotate round an inclined axis ; and the 

 inclination of this axis will incline more towards 

 either a vertical or a horizontal line, according as 

 the relative force of the one or the other system of 

 circulation may preponderate in any district. Since 

 the currents west of the vertical axes conform to 

 those above the horizontal axes, and the currents 

 east of the vertical axes conform to those below the 

 horizontal axes, the inclination of the axes resulting 

 from their combined action must therefore be from 

 west at the bottom of the ocean to east at the surface, 

 as shown in Plate VIII. And, in this inclined cir- 

 culation, since the ocean must preserve its level, the 

 inclination of the axes necessitates an elongation of 



