1820.] Franklin's Theory of Electricity. 44& 



see that he rejects this inference with a certain indignation 

 when it first presents itself, and that he is afterwards obhged to 

 reconcile himself to it. It was in fact hard to avow that it 

 depended merely upon the presence of the electric fluid whether 

 the atoms of all sulid bodies appeared to exercise upon each 

 other an action directly contrary to universal gravitation. It 

 was giving to the theory a very powerful and formidable oppo- 

 sition ; and in order to avoid this inconvenience, the electric fluid 

 was conceived to be formed by the union of two fluids, one of 

 which performs the function attributed by Q^pinus to the atoms 

 of bodies. 



In other French writers one also meets with similar reflections 

 against the theory of a simple electric fluid, as proposed by 

 M. CEpinus. " It is to be regretted (says M. Libes, Traite 

 Elementaire de Physique, Paris, 1801, tom. iii.p. 276) that the 

 way in which M. CEpinus has considered these two forces should 

 have led him to an inference contrary to the laws of gravitation, 

 and consequently inadmissible. We shall find (continues he) 

 that the theory of Coulomb (of two electric fluids) obviates this 

 disadvantage." 



I have no other remark to make here, except that if these 

 French philosophers had either known or duly considered the 

 observations pubhshed* by our respectable colleague, M. Von 

 Swinden, against the system of Q^pinus, they would not have 

 attached so much importance to the extension which Qilpinus 

 has given to Franklin's theory for the purpose of rejecting it, 

 and this merely because this extension of CEpinus, and his analy- 

 tical demonstrations, which are not sufficiently well grounded, 

 have induced him to admit an inference incompatible with the 

 law of universal gravitation. 



This extension given by Q^pinus to the theory of Franklin, 

 which has led him to the aforesaid conclusion, has, as it appears, 

 been judged indispensably necessary in order to explain electri- 

 cal phenomena, or else it has been thought that several of these 

 phenomena which might be explained by this untenable supposi- 

 tion could not be explained without it. What appeared particu- 

 larly inexplicable at the time of CEpinus was the repulsion or 

 separation of two negatively electrified bodies which could not 

 be accounted for without admitting a repulsive force existing in 

 the very matter of the bodies themselves. It seems that the 

 French philosophers are still of the same opinion. 



M. Haliy says, "the repulsion of bodies considered to be 

 negatively electrified has always been the stumbling block of all 

 theories. It was necessary to attempt to explain how these 

 bodies, each of which had lost a portion of its fluid, were deter- 

 mined to detach themselves from each other, while a superabun- 

 dance of fluid produced precisely the same eft'ect." 



♦ Recueil des Memoircs siir TAnalogie de rFJecJricU^ et du Magn^tisne cou- 

 ronnes par I'Academie de Baviere, la ilaye, 1784, tom. ii. p. 217. 



Vol. XVI. N'-- VI. 2F 



