64 THE OCEAN. [Book HI. 



And, as regards the earth's axial rotation east- 

 wards, we have shown that, in consequence of the 

 greater velocity of rotation in equatorial regions, vis- 

 inertite causes a current westwards in those regions, 

 counter- currents running eastwards through the 

 zones of lesser force in higher latitudes north and 

 south. In this case, the vis -inertias acting in equa- 

 torial regions with greater force than in higher 

 latitudes — in proportion with the greater velocity of 

 the motion of rotation in those regions compared with 

 that in higher latitudes — is the force of astral gravi- 

 tation, which holds all particles equally to the posi- 

 tion which it tends to give them ; but as the surface 

 of the earth in the equatorial regions moves more 

 rapidly than m higher latitudes, the particles in those 

 regions have a great relative tendency in the oppo- 

 site direction to that of the surface on which they 

 rest ; because the surface runs with greater velocity 

 from under the particles as they move towards the 

 position which astral gravitation tends to give them. 

 And over those parts of the surface of the earth 

 where the action of astral gravitation is less, the 

 particles, being relatively more under the dominion 

 of the earth's gravitation, are drawn into the positions 

 in relation to the surface of the earth which the par- 

 ticles most under the dominion of astral gravitation 

 ^end to vacate. Thus, as astral gravitation gives the 

 water a relative motion in the opposite direction to 

 that of the surface of the earth in the equatorial 



