NATUKAL PHILOSOPH1. 163 



their dissociation they, by the assumption, pass into the powerless state again, 

 and this would be equivalent to the annihilation of force. It will be easily 

 understood that the case of the sun and the earth, or of any one of two or 

 more acting bodies is reciprocal, and also that the variation of attraction, 

 with any degree of approach or separation of the bodies involves the same 

 result of creation or annihilation of powers as the creation or annihilation of 

 either of the acting bodies would do. 



Such, I think, must be the character of the conclusion, if it be supposed 

 that the attraction of the sun upon the earth arises because of the presence 

 of the earth, and the attraction of the earth upon the sun because of the 

 presence of the sun ; there remains the case of the power or the efficient 

 source of the power having pre-existed in the sun (or the earth) before the 

 earth (or the sun) was in presence-. In the latter view it appears to me that, 

 consistently with the conservation of force, one of three sub-cases must oc- 

 cur ; either the gravitating force of the sun, when directed upon the earth, 

 must be removed in an equivalent degree from some other bodies, and when 

 taken off from the earth (by the disappearance of the latter), be disposed of 

 on some other bodies ; or else it must take up some new form of power when 

 it ceases to be gravitation, and consume some othj^ form when it is devel- 

 oped as gravitation; or else it must be always existing around the sun 

 through infinite space. The first sub-case is not imagined by the usual hy- 

 pothesis of gravitation, and will hardly be supposed probable ; for if it were 

 true, it is scarcely possible that the effects should not have been observed 

 by astronomers, when considering the motion of planets in different positions 

 with respect to each other and the sun. Moreover, gravitation is not assumed 

 to be a dual power, and in them only as yet have such removals been ob- 

 served by experiment or conceived by the mind. The second sub case, or 

 that of a new or another form of power, is also one that has never been 

 imagined by others, hi association with the theory of gravity. I made some 

 endeavors, experimentally, to connect gravity with electricity, having this 

 very object in view, but the results were entirely negative. The view, if held 

 for a moment, would imply that not merely the sun. but all matter, whatever 

 its state, would have extra powers set up in it, if removed in any degree 

 from gravitation ; that the particles of a comet at its perihelion would have 

 changed in character, by the conversion of some portion of their molecular 

 force into the increased amount of gravitating which they would then exert ; 

 and that at its aphelion this extra gravitating force would have been con- 

 verted back into some other kind of molecular force, having either the former 

 or a new character ; the conversion either way being to a perfectly equivalent 

 degree. One could not even conceive of the diffusion of a cloud of dust, or its 

 concentration into a stone, without supposing something of the same kind to 

 occur ; and I suppose nobody will accept the idea as possible. The third sub- 

 case remains, namely, that this power is always existing around the sun and 

 through infinite space, whether secondary bodies be there to be acted upon by 

 the gravitation or not ; and not only around the sun, but around eveiy particle 

 of matter which has existence. This case of a constant necessary condition 

 to action hi space, when as respects the sun the earth is not in place, and of 



