448 On the gravitating Force. [1857. 



the two particles A and B as attracting each other by the force 

 of gravitation, under another view. According to the defini- 

 tion, the force depends upon both particles, and if the particle 

 A or B were by itself, it could not gravitate, i. e. it could have 

 no attraction, no force of gravity. Supposing 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 trying to imagine how 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 particles, and so to bring ourselves 

 within the impossible consequences which have already been 

 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 particle 

 is alone, or one of a universe of other particles, it is always re- 

 lated. 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 distance from A 

 and then the power in A will be infinitely diminished. Such 

 removal of B will be as if it were annihilated 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 di- 

 stances only are considered, become one, being identical with 

 each other in their consequences. And as removal of B to an 

 infinite distance is as regards A annihilation of B, so removal 

 to the smallest degree is, in principle, the same thing with dis- 

 placement 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 con- 

 sequence 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 of 

 thought grows up in the mind if we consider the mutual gra- 



