THE CASE OF GRAVITATING PARTICLES. 365 



ing A to exist in that isolated state and without gravitating 

 force, and then B placed in relation to it, gravitation comes 

 on, as is supposed, on the part of both. Now, without try- 

 ing to imagine liow B, which had no gravitating force, can 

 raise up gravitating force in A ; and how A, equally without 

 force beforehand, can raise up force in B, still, to imagine it 

 as a fact done, is to admit a creation of force in both parti- 

 cles ; and so to bring ourselves within the impossible conse- 

 quences which have been already referred to. 



It may be said we cannot have an idea of one particle by 

 itself, and so the reasoning fails. For my part I can compre- 

 hend a particle by itself just as easily as many particles ; and 

 though I cannot conceive the relation of a lone particle to 

 gravitation, according to the limited view which is at present 

 taken of that force, I can conceive its relation to something 

 which causes gravitation, and with which, whether the parti- 

 cle is alone, or one of a universe of other particles, it is al- 

 ways related. But the reasoning upon a lone particle does 

 not fail ; for as the particles can be separated, we can easily 

 conceive of the particle B being removed to an infinite dis- 

 tance from A, and then the power in A will be infinitely di- 

 minished. Such removal of B will be as if it were annihi- 

 lated in regard to A, and the force in A will be annihilated 

 at the same time ; so that the case of a lone particle and that 

 where different instances only are considered become one, be- 

 ing identical with each other in their consequences. And as 

 removal of B to an infinite distance is as regards A annihila- 

 tion of B, so removal to the smallest degree is, in principle, 

 the same thing with displacement through infinite space ; the 

 smallest increase in distance involves annihilation of power ; 

 the annihilation of the second particle, so as to have A alone, 

 involves no other consequence in relation to gravity ; there is 

 difference in degree, but no difference in the character of the 

 result. 



It seems hardly necessary to observe, that the same line 



