174 THE OCEAN. [Book VU. 



CHAPTER XVI. 



EEFUTATION OF AN ARGUMENT SUGGESTING A SUS- 

 PENSION OF THE ACTION OF GRAVITATION. 



I HAVE heard it asserted that the spinning of a top 

 shows that its motion causes the action of gravitation 

 on it to be suspended whilst that motion lasts. But 

 this is an unnecessary assumption. I say that the 

 direct action of gravitation tending to make it fall 

 is exactly the same as if it were at rest, and that 

 astral gravitation is the force which keeps the top 

 from falling. For as the relative number of the 

 orbital revolutions of the planets in a given time 

 increases as the square root of the sun's revolving 

 force, it may, I think, be admitted that the resist- 

 ance of astral gravitation increases as the square of 

 the velocity of the motion which it resists. As far 

 as the present argument is concerned, it is, however, 

 immaterial whether the force of astral gravitation 

 increases as the square or as the cube of the velocity 

 or in any other ratio. Let us suppose it to increase 

 as the square. 



Then let the falling motion be any amount, say 

 4 ; and the mean rotating motion of one half of the 

 top in any direction 8. 



