182 ANNUAL OF SCIENTIFIC DISCOVERY. 



of force generally. The conservation of force is a fundamental principle ; 

 hence the assumption with regard to a particular form of force ought to im- 

 ply what becomes of the force when its action is increased or diminished, or 

 its direction changed ; or else the assumption should admit that it is deficient 

 on that point, being only half competent to represent the force ; and, in any 

 case, should not be opposed to the principle of conservation. The usual 

 definition of gravity as an attractive force between the particles of matter VARY- 

 ING inversely as the square of the distance, whilst it stands as a full definition 

 of the power, is inconsistent with the principle of the conservation of force. 

 If we accept the principle, such a definition must be an imperfect account of 

 the whole of the force, and is probably only a description of one exercise of 

 that power, 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 during the suspended or diminished de- 

 gree in its power as gravitation, equal in importance to the power suspended 

 or hidden ; being in fact equivalent to that diminution. It ought also to ad- 

 mit, 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 

 aud insufficient ; if it admits these things, or any part of them, then it pre- 

 pares the natural philosopher to look for effects and conditions as yet un- 

 known, 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 investiga- 

 tion, 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 proportion- 

 ately growing up ; and again, that when their distance is diminished, as 

 from ten to one, the power of attraction, now increased a hundred-fold, has 

 been produced out of some other form of power which has been equivalently 

 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 assump- 

 tion 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 

 destroyed 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 therefore be supposed that a very large apparent 

 amount of the force causing the phenomena of gravitation, may be the 



