OHM ON THE GALVANIC CIRCUIT. 4G9 



place of the circuit, brought into contact with M, has assumed 

 when no new tension originates at this place of contact ; under 

 this supposition therefore 



r (u' — n) 



« = — IT-' 



whence we find 



r + R 



From this equation it results that the electroscopic force in the 

 body Mwill constantly be smaller than it was at the touched place 

 before contact ; and also that both will approximate the more 

 to each other, the greater r is in comparison to R. If we regard 

 R as a constant magnitude, the relation of the electroscopic 

 forces u and u' to each other depends solely upon the mag- 

 nitude of the space which the electricity occupies in the circuit ; 

 we can therefore bring the electroscopic force of the body M 

 nearer to its greatest value solely by increasing the capacity 

 of the circuit, either by a general increase of its dimensions, 

 or by attaching anywhere to it foreign masses. Upon the 

 nature of these masses, when they are merely conductors of 

 electricity, and do not give rise to new tensions, none of this 

 effect, in my opinion, depends, but solely upon their mag- 

 nitudes. If the attached masses occupy an infinitely great 

 space, which case occurs when the circuit has anywhere a com- 

 plete deduction, then the electroscopic force in the body M will 

 constantly be equal to that which the place of the circuit touch- 

 ed by it possesses. 



To connect these effects with the action of the condenser, we 

 have merely to bear in mind, that a condenser, whose magnitude 

 is R, and whose number of charges is m, must be con- 

 sidered equal to a common conductor of the magnitude m R, 

 yet with the difference that its electroscopic force is m times 

 that of the common conductor. If, therefore, we designate 

 by u the electroscopic force of the condenser, which is brought 

 into connexion with a place of the circuit whose force is u', we 

 obtain 



r+mR' 

 whence it follows that the condenser will indicate m times the 

 force of the touched place when r is veiy great in comparison 

 with m R ; but that it will liave a weakening action so soon as r is 



VOL. II. PAUT VIII. 2 1 



