CuAP. XV.] IIEFUTATIOX OF OBJECTIOXS. 1G9 



even in the least degree modify or affect those posi- 

 tions, — let this, then, also be admitted : and even then, 

 supposing all the particles of which either the ocean 

 or the atmosphere is composed to be of the same 

 specific gravity, it is then clearly of no importance, as 

 far as the laws of gravitation are concerned, how those 

 particles arrange themselves in relation to each other 

 within the bounds in which gravitation tends to hold 

 them. The particles may indeed, as far as gravita- 

 tion is concerned, arrange themselves in any con- 

 ceivable manner : and if any causes whatever tend to 

 set the particles in motion, all that the laws of gravi- 

 tation can require is, that as particles vacate any 

 position they must immediately be replaced by other 

 particles. It is of no importance, as far as gravitation 

 is concerned, what the forces may be which cause the 

 particles to exchange positions. If anything cause 

 a difference in the relative specific gravity of the 

 particles, then gravitation will itself cause them to 

 exchange positions. Or, if any force whatever be 

 brought into play, acting with greater force in one 

 direction, or in one place, than in another, among 

 particles of equal specific gravity, then, since, as far 

 as gravitation is concerned, the particles may ex- 

 change positions in any conceivable manner, and 

 since a cause exists to move some of the particles, a 

 motion must be effected. When force, unopposed by 

 equal force, urges particles from any position, they 

 leave it, and, simultaneously with their motion from 



