102 THE OCEAN. [Book IV. 



Discarding in this manner the individual action 

 of the sun and moon, we have seen tliat the ocean 

 has a tendency to maintain the position from which 

 the surface on which it rests tends to carry it : and 

 that this tendency results from its property of vis- 

 inerti^B, in the ordinary acceptation of the term ; hut 

 we have also seen that the action of vis-inertite which 

 resists motion towards the position which the earth's 

 power of gravitation tends to give, is a power of 

 gravitation drawing towards the position which the 

 combined action of all powers of gravitation, except- 

 ing that of the earth, tends to give. To this force 

 we have applied the term ' astral gravitation,' because 

 we have ascertained that vis-inertise is really uni- 

 versal gravitation, which this force is not. 



The oceanic circulation resulting from the con- 

 flicting action of these forces of terrestrial and astral 

 gravitation we have described at length m Book 11. , 

 in which we have shown that, as regards the onward 

 motion of the earth, in those parts of the ocean least 

 under the dominion of the earth's gravitation, a 

 current is drawn through the ocean, by the attraction 

 of astral gravitation, m the opposite direction to that 

 of the motion of the surface of the earth ; whilst in 

 those parts of the ocean most under the dominion of 

 the earth's power of gravitation counter- currents are 

 drawn through the ocean, by the earth's gravitation, 

 in the direction of the motion of the surface of the 

 earth. 



