and the Nature of Matter. 143 



can be supposed of the disposition of forces in or about a solid 

 nucleus of matter, which cannot be equally conceived with 

 respect to a centre. 



In the view of matter now sustained as the lesser assump- 

 tion, matter and the atoms of matter would be mutually pene- 

 trable. As regards the mutual penetrability of matter, one 

 would think that the facts respecting potassium and its com- 

 pounds, already described, would be enough to prove that 

 point to a mind which accepts a fact for a fact, and is not 

 obstructed in its judgement by preconceived notions. With 

 respect to the mutual penetrability of the atoms, it seems to 

 me to present in many points of view a more beautiful, yet 

 equally probable and philosophic idea of the constitution of 

 bodies than the other hypotheses, especially in the case of che- 

 mical combination. If we suppose an atom of oxygen and an 

 atom of potassium about to combine and produce potash, the 

 hypothesis of solid unchangeable impenetrable atoms places 

 these two particles side by side in a position easily, because 

 mechanically, imagined, and not unfrequently represented; 

 but if these two atoms be centres of power they will mutually 

 penetrate to the very centres, thus forming one atom or mole- 

 cule vvith powers, either uniformly around it or arranged as 

 the resultant of the powers of the two constituent atoms; and 

 the manner in which two or many centres of force may in this 

 way combine, and afterwards, under the dominion of stronger 

 forces, separate again, may in some degree be illustrated by 

 the beautiful case of the conjunction of two sea waves of dif- 

 ferent velocities into one, their perfect union for a time, and 

 final separation into the constituent waves, considered, I think, 

 at the meeting of the British Association at Liverpool. It 

 does not of course follow, from this view, that the centres shall 

 always coincide; that will depend upon the relative disposi- 

 tion of the powers of each atom. 



The view now stated of the constitution of matter would 

 seem to involve necessarily the conclusion that matter fills all 

 space, or, at least, all space to which gravitation extends (in- 

 cluding the sun and its system); for gravitation is a property 

 of matter dependent on a certain force, and it is this force 

 which constitutes the matter. In that view matter 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, at first sight, seems to fall in 

 very harmoniously with Mossotti's mathematical investiga- 

 tions and reference of the phaenomena of electricity, cohesion, 

 gravitation, &c. to one force in matter ; and also again with 

 the old adage, " matter cannot act where it is not." But it 



