,350 A Reply io Mr. D.omvau's Ohservalions 



was resumed. Mr. De Luc explains this by supposiiig, that al* 

 though the balls were at first in the natural .state when com- 

 pared with the electric state of that room ; yet, when brought 

 into an air containing a greater aljsolute quantity of electricity, 

 tliey became relatively ?!c-gatiie. Now if this admits a different 

 explanation, the necessity of the above inference is destroyed j 

 it is therefore of importance to try if this can be effected. ..... 



Now it appears to n)e, tiiat the principle of electric influence 

 may be applied in ex])laiiatiou of Mr, De Luc's GX]jcrimciits on 

 electrified air. The balls in the natural state are brought into 

 a positive otrnosplitre ; the electricity of the latter repels the 

 natural quantity of the balls into their internal substance; the 

 external parts therefore are left minus. Vv'ith this view the - 

 sequel exactly corresponds; for, when the bails were l)ror.ghtback. 

 into the vnetectrijicd room, they collapsed into their natural 

 state. But on the opposite view, the balls bv immersion into a 

 positive atTTcOSphere would assume that state and retain it when 

 removed, and therefore continue to diverge. Hence it appears 

 to me, that tire experiment is an anomalv on the hvpotliesis of 

 Volta, and perfectly reconcileable to the principle of Franklin." 



I think that some further explanations will remove Mr. Do- 

 novan's cliiiicultles ; and the most direct v.'ay will be by stating 

 in what consists the difference between the two theories. — In 

 Dr. Franklin's, the standard of plus and winus was a certaiij 

 (supposed) natural qxuiniity of electrify belonging to all the sub- 

 stances of our globe, which fixation as niercly arbitrary, and 

 opposed by facts, prevented that theory, though true in itself, 

 from being admitted i)y a great nuniber of natural iihilosophers 

 both in England and on the continent ; it v.as even by such 

 strong arguments explained in my \vorkR, that thev were never 

 answered by retaining tluit theory. 



But Volta's theory has pioduccd two great and permanent 

 thaiigcs in the science of cicctricity. He first proved that there 

 is no fixed nor permanent standard vf plus and mi/ii/s ; that the 

 standard was changeable, being the actual electric slate of am- 

 iirnt air. He next explained the cav.se of the electric motions 

 oi pairs rif halls, hy proving thato//' possesses the elect ric fluid us 

 well as all the bodies which it embraces; but with, this circum- 

 stance, that it abandons some to the bodies that have less, and 

 takes some from those which have tnore than itself : lastly, that 

 as the electric Jluid ha,s some adhesion to the bodies which 

 possess it, if these bodies oppose less resistrnce to move than to 

 jjart with the excess, or to receive their deject, they are trans- 

 ported by the electric fluid where it has a tendency to move. 



I have demonsl. ated that effect by an analogous experiment 

 made with a pair of small soap disks suspended by thin thrca<ls, 



as 



