GRAVITATION BUT PARTIALLY UNDERSTOOD. 367 



probably only a description of one exercise of that power, 

 whatever the nature of the force itself may be. If the defi- 

 nition be accepted as tacitly including the conservation of 

 force, then it ought to admit that consequences must occur 

 during the suspended or diminished degree 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 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 re- 

 lated to, conditions external or internal to the gravitating par- 

 ticle ; 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 ig- 

 nores them, I think it is imperfect and insufficient ; if it ad- 

 mits 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 improvement ; 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, be- 

 cause of increasing distance, then some other exertion of 

 power, either within or without them, is proportionately grow- 

 ing 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 philosophi- 

 cal and more in accordance with all physical considerations. 



