230 KINETIC THEORIES OF GRAVITATION. 



powers we know and recognize in every phenomenon of the creation ; 

 the abstract matter in none ; why then assume the existence of that of 

 which we are ignorant, which we cannot conceive, and for which there 

 is no philosophical necessity ? .... Doubtless the centers of force 

 vary in their distance one from another, but that which is truly the 

 matter of one atom touches the matter of its neighbors. Hence matter 

 will be continuous throughout, and in considering a mass of it, we have 

 not to suppose a distinction between its atoms and any intervening 

 space. The powers around the centers give these centers the properties 

 of atoms of matter; and these powers again, when many centers by 

 their conjoint forces are grouped into a mass, give to every part of that 



mass the properties of matter The view now stated of the 



constitution of matter would seem to involve necessarily the conclu- 

 sion that matter fills all space, or at least all space to which gravitation 

 extends ; for gravitation is a i>roperty of matter dependent on a certain 

 force, and it is this force which constitutes matter. In that view, mat- 

 ter is not merely mutually penetrable, but each atom extends, so to say, 

 throughout the whole of the solar system, yet always retaining its own 

 centre of force."* 



This result of " assuming as little as possible" thus appears to com- 

 mence with the Berkeleyau negation of matter, only to conclude that it 

 is omnipresent. When it is inferred however, that every atom sepa- 

 rately includes every other atom, it is obviously only injluence that is 

 conceived of, and not matter at all in any intelligible sense. If we call 

 this multitudinous infinitely-extended and mutually-inclusive influence 

 " matter," there still remains the inexorable necessity of designating by 

 some distinctive title that other form of influence inclosed within the 

 visible tangible surfaces bounding those appearances which are charac- 

 terized by inertia, which are accurately measurable in mass, and which 

 are the objects of all our direct observation and experiment. ^Neither in 

 formula, nor in idea, therefore, — neither in nominalism, nor in realism, — 

 are we advanced a particle by such speculations. 



In a memoir " On the Possible Relation of Gravity to Electricity," 

 read before the Royal Society, November 28, 1850, Faraday remarks: 

 "The long and constant persuasion that all the forces of nature are 

 mutually dependent, having one common origin, or rather being differ- 

 ent manifestations of one fundamental power, has made me often think 

 upon the possibility of establishing by experiment, a connection between 

 gravity and electricity, and so introducing the former into the group, 

 the chain of which (including magnetism, chemical force, and heat,) 

 binds so many and such varied exhibitions of force together bj' common 

 relations." He then records experiments with a tubular helix of cov- 

 ered copper wire of considerable length, and having its extremities 

 connected with long covered wires which were brought to a very sensi- 

 tive galvanometer, the said coil or helix being allowed to fall about 



* L. E. D. Philosophical Magazine, lt44, vol. xxiv, pp. 140-143. 



