468 OHM ON THE GALVANIC CIRCUIT. 



ceptible ; consequently its various gradations in the extent of 

 the portion A are very easily perceptible. This conclusion is of 

 importance, because it affords the means of presenting to the 

 senses the law of electric distribution even on compound cir- 

 cuits, when it is no longer possible on the simple circuit, on 

 account of its extremely feeble force. It is, moreover, immedi- 

 ately evident, that, with equal tensions, this phaenomenon will 

 be indicated with greater intensity, the greater \ is in compari- 

 son with A. 



21. A phaenomenon common to all galvanic circuits is the 

 sudden change to which its electroscopic force may incessantly, 

 and arbitrarily, be subjected. This phaenomenon has its source 

 in the previously developed properties of such circuits. Since, 

 as we have found, each place of a galvanic circuit undergoes the 

 same alterations to which a single one is exposed, we have it in 

 our power to give sometimes one, sometimes another value to 

 the electroscopic force at any certain place. Among these 

 changes those are the most remarkable which we are able to 

 produce by deductive contact, i. e. by destroying the electro- 

 scopic force sometimes at one, and sometimes at another place 

 of the circuit ; its magnitude, however, has its natural limits in 

 the magnitude of the tensions. 



There is another class of phaenomena which is immediately 

 connected with these. If, for instance, we call r the space 

 over which the electroscopic force is diffused in a given gal- 

 vanic circuit, u the electroscopic force of the circuit at one of 

 its points, which is immediately connected with an external 

 body M, and u' the electroscopic force of the same circuit at 

 the same place as it was previous to contact with the body My 



yi u is evidently the alteration in the electroscopic force pro'j 



duced at this place ; consequently, since this change likewise 

 occurs uniformly at all the other places of the circuit, r {u' — MM 

 is the quantity of electricity which the change produced over! 

 the entire circuit comprises, and accordingly that which has! 

 passed over into the body M. If now we suppose that in tl 

 state of equilibrium the electroscopic force is everywhere 

 equal intensity at all places of the body M in which it occurs, ani 

 represent by R the space over which it is diffused in the bodi 



M, then its electroscopic force is evidently — ^— p — -. But tl 



force is in the state of equilibrium equal to the u', which th| 



