to account for the Phcenome7ia of Electricity . 339 



dencc entirely depends on the supposition that electricity is then 

 issuing out. But this itself is no mere than an assumption, 

 therefore, the fact proves nothing : and even were the direction 

 of the fluid admitted, it v.ould still afford no evidence. For if 

 the divergence be occasioned by the repulsion of the particles 

 as an essential property, it is evident that the same effects 

 must be produced in all cases where the fluid is at liberty. 

 Where a property of matter acts on similar matter only, the 

 eifccts caimot be dependant on any other body. Now what- 

 ever the divergence may be in air, which resists the electric 

 matter, it must be much greater in a medium which offers little 

 or no resistance, if the divergence depend on an essential pro- 

 perty of the ))artlcle.s themselves. But (jviite contrary is the fact, 

 for it is well known that electricity, during its passage through a 

 long exhau-^^ted receiver, passes with scarcely any appearance of 

 divergence : jjarallel rays traverse from one end to the other. 

 The mom.ent that air is let in, the divergence appears; evidently 

 proving that it is the medium and not a property of the electric 

 matter which produces the effect. 



Thus it appears that these two facts do not bear out the sup- 

 position of ela: ticity wliich has been founded on them. I do not 

 inetend to say that the electric matter is not elastic ; it may, or 

 it may not: I see no more evidence in favour of one opinion 

 than the other. Yet on this principle rest the doctrines con- 

 cerning the re])ulsion of similarly electrified bodies, the charging 

 of jars, and equilibria. 



2. l"he second principle is that electricity attracts all matter. 

 All matter must tlien attract electricity, and therefore the latter 

 is dispersed throughout all bodies. Franklin adds " we know 

 the electrical fluid is in common matter, because we can pump 

 it out by the globe or tube. We know that conunon matter 

 has near as much as it can contain, because, when we add a 

 little more to aiiy portion of it the additional quantity does not 

 enter, but forms an electric atmosphere. And we know that 

 conimcn matter has not (generally) more than it can contain ; 

 otherwise all loose portions of it would repel each other, as they 

 constantly do when they have electric atmospheres*." This is 

 proving one a'^sertion by another which is no more than an hy- 

 ])othesis, and which docs not even seem to be well founded as 

 \viU presently appear. Had it been established that we i!o ac- 

 cumulate the fluid it might then be allowed that it is pumped 

 out. That common matter has as nmch electricity as it can 

 contain, he proves by the formation of atmospheres : but we may 

 as well suppose with /Epiims and others, that electrical atmo- 

 •pheics do not exist. 



* Tranklin's Letters, .OG. 



Y 2 Concerninjj 



