258 



THE OCEAN. 



[Book X. 



pole. And let the circle a b c d he the form which 

 the ocean would take with the earth at rest. 



Then give the earth an axial rotation in the plane 

 of the equator, w e. 



This rotation creates a centrifugal force which 

 gives the particles of water resting on each parallel 

 of latitude a tendency to rise from the circles in 

 which they are revolved. 



Thus, under the action of the centrifugal force, 

 particles on the equator, w e, tend to rise frolii e 

 towards g in the plane of the equator ; and particles 

 on the parallel z x tend to rise in the direction x t, 

 parallel to the equator. But the earth's gravita- 

 tion, acting across the plane x t in the du-ection v r, 

 draws the latter particles towards the equator. 



Thus, as the centrifugal force tends to carry off 



