260 THE OCEAN. [Book X. 



to displace those at e, and that of the particles at e 

 tends to cause them to displace those at g, the latter 

 are by the earth's gravitation (being released from 

 the immediate action of the centrifugal force) drawn 

 back towards/, and thus supply the sinking motion 

 from / to N. 



A constant circulation in the directon e ^ / n e 

 is thus established with the ocean in equilibrium. 



3. Also, because, being less firmly held by the 

 earth's gravitation, the particles in the YmQfu are 

 more free to flow towards the equator under the 

 action of the centrifugal force, than those in the line 

 N y ; therefore, there is a tendency to a circulation in 

 the direction y 'N f u g i: y. 



But, as the excess of this horizontal force, tending 

 to cause a circulation with an upward motion about 

 the poles, is greatest in the polar regions, and 

 decreases gradually towards the equator, where it 

 ceases to act ; and the excess of the vertical force 

 previously described as tendmg to cause a circulation 

 with an upward motion about the equator, is greatest 

 in the equatorial regions, and decreases gradually 

 towards the pole, where it ceases to act ; therefore, 

 the sinking motion must be in an intermediate latitude 

 with a circulation in the direction u y 's f u in the 

 polar regions, and in the direction ii y e g u in the 

 equatorial regions. 



4. Also, because the retarding and centrifugal 

 force of astral gravitation, being as the square of the 



