Prof. Faraday on the Conservation of Force. 231 



whatever the nature of the force itself may be. If the definition 

 be accepted as tacitly including the conservation of force, then it 

 ought to admit that consequences must occur dm*ing the sus- 

 pended or diminished degree of its power as gravitation equal in 

 importance to the power suspended or hidden ; being, in fact, 

 equivalent to that diminution. It ought also to admit that it is 

 incompetent to suggest or deal with any of the consequences of 

 that changed part or condition of the force, and cannot tell 

 whether they depend on, or are related to, conditions external or 

 internal to the gravitating particle ; and, as it appears to me, can 

 say neither yes nor no to any of the arguments or probabilities 

 belonging to the subject. 



If the definition denies the occurrence of such contingent results, 

 it seems to me to be unphilosophical ; if it simply ignores them, 

 I think it is imperfect and insufficient ; if it admits these things, 

 or any part of them, then it prepares the natural philosopher to 

 look for effects and conditions as yet unknown, and is open to 

 any degree of development of the consequences and relations of 

 power : by denying, it opposes a dogmatic barrier to improve- 

 ment ; by ignoring, it becomes in many respects an inert thing, 

 often much in the way ; by admitting, it rises to the dignity of 

 a stimulus to investigation, a pilot to human science. 



The principle of the conservation of force would lead us to 

 assume, that when A and B attract each other less because of 

 increasing distance, then some other exertion of power either 

 within or without them is proportionately growing up ; and 

 again, that when their distance is diminished, as from 10 to 1, the 

 power of attraction, now increased a hundredfold, has been pro- 

 duced out of some other form of power which has been equiva- 

 Icntly reduced. This enlarged assumption of the nature of 

 gravity is not more metaphysical than the half assumption, and 

 is, I believe, more philosophical, and more in accordance with all 

 physical considerations. The half assumption is, in my view of 

 the matter, more dogmatic and irrational than the whole, because 

 it leaves it to be understood that power can be created and de- 

 stroyed almost at pleasure. 



When the equivalents of the various forms of force, as far as 

 they are known, are considered, their differences appear very 

 great; thus a grain of water is known to have electric relations 

 equivalent to a very powerful flash of lightning. It may there- 

 fore be supposed that a very large amount of the force causing 

 the phienomcna of gravitation may be the equivalent of a very 

 small change in some unknown condition of the bodies, whose 

 attraction is varying by change of distance. For my own part, 

 many considerations urge my mind towards the idea of a cause 

 of gravity which is not resident in the particles of matter merely, 



