230 Prof. Faraday on the Conservation of Force. 



it were annihilated in regai-d to A, and the force in A will be 

 annihilated at the same time; so that the case of a lone particle 

 and that where different distances only are considei-ed become 

 one, being identical with each other in their consequences. And 

 as removal of B to an infinite distance is as regards A annihila- 

 tion of B, so removal to the smallest degree is in principle the 

 same thing with displacement through infinite space : the small- 

 est increase in distance involves annihilation of power ; the an- 

 nihilation of the second particle, so as to have A alone, involves 

 no other consequence in relation to gravity; there is diflference 

 in degree, but no difference in the character of the result. 



It seems hardly necessary to observe, that the same line of 

 thought grows up in the mind if we consider the mutual gravi- 

 tating action of one particle and many. The particle A will 

 attract the particle B at the distance of a mile with a certain 

 degree of force ; it will attract a particle C at the same distance 

 of a )nile with a power equal to that by which it attracts B ; if 

 myriads of like particles be placed at the given distance of a mile, 

 A will attract each with equal force ; and if other ])artic]es be ac- 

 cumulated round it, within and without the sphere of two miles 

 diameter, it will atti-aet them all with a force varying inversely with 

 the square of the distance. How are we to conceive of this force 

 growing up in A to a millionfold or more ? and if the surround- 

 ing particles be then removed, of its diminution in an equal 

 degree ? Or how are we to look upon the power raised up in all 

 these outer particles by the action of A on them, or by their 

 action one on another, without admitting, according to the 

 limited definition of gravitation, the facile generation and anni- 

 hilation of force ? 



The assumption which we make for the time with regard to 

 the nature of a power (as gravity, heat, &c.), and the form of 

 words in which we express it, i. e. its definition, should be con- 

 sistent with the fundamental principles of force generally. The 

 conservation of force is a fundamental principle; hence the 

 assumption with regard to a particular form of force ought to 

 imply 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 compe- 

 tent 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 hetiveen the particles of matter varying 

 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 defini- 

 tion must be an imperfect account of the whole of the force, and 

 is probably only a description of one exercise of that power, 



