328 Prof. Faraday on the Conservation of Force. 



If the principle be accepted as true, we have a right to pursue 

 it to its consequences, no matter what they may be. It is, 

 indeed, a duty to do so. A theory may be perfection, as far as 

 it goes, but a consideration going beyond it is not for that reason 

 to be shut out. We might as well accept our limited horizon as 

 the limits of the world. No magnitude, either of the phsenomena 

 or of the results to be dealt with, should stop our exertions to 

 ascertain, by the use of the principle, that something remains to 

 be discovered, and to trace in what direction that discovery 

 may lie. 



I will endeavour to illustrate some of the points which have 

 been urged, by reference, in the first instance, to a case of power 

 which has long had great attractions for me, because of its 

 extreme simplicity, its promising nature, its universal presence, 

 and its invariability under like circumstances ; on which, though 

 I have experimented* and as yet failed, I think experiment 

 would be well bestowed : I mean the force of gravitation. I 

 believe I represent the received idea of the gravitating force 

 aright, in saying that it is a simple attractive force exerted between 

 any two or all the particles or masses of matter, at every sensible 

 distance, but with a strength varying inversely as the square of the 

 distance. The usual idea of the force implies di7'ect action at a 

 distance ; and such a view appears to present little difficulty 

 except to Newton, and a few, including myself, who in that 

 respect may be of like mind with himj- 



This idea of gravity appears to me to ignore entirely the prin- 

 ciple of the conservation of force ; and by the terms of its defi- 

 nition, if taken in an absolute sense " varying inversely as the 

 square of the distance," to be in direct opposition to it ; and it 

 becomes my duty now to point out where this contradiction 

 occurs, and to use it in illustration of the principle of conserva- 

 tion. Assume two ])articles of matter, A and 13, in free space, 

 and a force in each or in both by which they gravitate towards 

 each other, the force being unalterable for an unchanging di- 

 stance, but varying inversely as the square of the distance when 

 the latter varies. Then at the distance of 10 the force may be 

 estimated as 1 ; whilst at the distance of 1, i. e. one-tenth of the 

 former, the force will be 100; and if we suppose an elastic 

 spring to be introduced between the two as a measure of the 

 attractive force, the power compressing it will be a hundred times 

 as much in the latter case as in the former. But from whence 

 can this enormous increase of the power come ? If we say that 

 it is the character of this force, and content ourselves with that 

 as a sufficient answer, then it appears to me we admit a creation 

 of power, and that to an enormous amount ; yet by a change of 



* Philosophical Transactions, 185], p. 1. f See Note, p. 232. 



