458 Mr. J. Croll on certain Hypothetical Elements 



and not a property or quality, the most philosophic way is to say, 

 with Faraday *, that the atom is simply a centre of force, and 

 what we call matter is simply a power of resistance acting in a 

 certain part of space, thus making no hypothetical statement of 

 any kind regarding the nature of this cause or power. 



But the hardness or resistance manifested to our experience 

 is considered by those who adopt the ordinary theory to be a 

 property or quality of a substance, not the effect of a cause. But 

 this does not afford any warrant for assuming the existence of 

 solid impenetrable atoms. It will not do to say that there can 

 be no resistance without solidity. All that we require to affirm 

 is that there must be a something possessed of the property or 

 quality of resistance — a something which manifests itself as re- 

 sistance in space. What we must believe is that there exists a 

 substance or subject to which the resistance belongs. 



The necessity for assuming the existence of a something to 

 which these properties belong is purely metaphysical. The me- 

 taphysical necessity under which we lie obliges us to postulate 

 the existence of a something ; but it does not necessitate us to 

 form any conceptions regarding the nature of this something. 

 Its nature can only be learned by experience, through the pro- 

 perties manifested. If we experience resistance in space, then 

 metaphysically we must assume the existence of a something 

 which resists. This is all. We are not warranted from this pro- 

 perty manifested to begin and speculate on the nature of this 

 something. If it should manifest other properties than resist- 

 ance, these other properties will give us further information re- 

 garding its nature. But if it does not manifest any other pro- 

 perty than simple resistance, all that we can ever possibly say is 

 that a something resists, but what this something actually is, 

 further than a power of resistance, must in such a case remain 

 for ever unknown. Some even believe that . if you deprive 

 matter of that imaginary quality called solidity you annihilate it 

 altogether. Of course, if solidity be a property of matter, and 

 you annihilate the solidity, you annihilate matter as a something 

 existing as a solid. But this is not exactly what those to whom 

 I refer mean. They mean that actual existence depends upon 

 solidity, and that there can be no existent something manifest- 

 ing itself in space as resistance unless it be in possession of this 

 solidity. 



It has been asserted that the idea of vis inertia is irreconci- 

 lable with the hypothesis that matter consists of centres offeree. 

 It is certainly true that, whatever views we may adopt regarding 

 the physical constitution of matter, vis inertia, under some form 



* Phil. Mag. for February 1844, and May 1846. 



