418 OHM ON THE GALVANIC CIRCUIT. 



7a, because the ordinate Z W is equal to that of A F. If the cir- 

 cuit were touched at the place where the two parts A B and B C 

 join, but so that the contact was made within the part B C, 

 we should have to imagine A D advanced to N O ; the elec- 

 trical force at the point S would in this case be increased to 

 the force indicated by T Y". But if the contact took place, 

 still at the same point, viz. where the parts A B and B C touch 

 each other, but within the part A B, the line A D would be 

 moved to P Q., and the force belonging to the point S would 

 sink to the negative force expressed by U Y". If, lastly, the 

 pile had been touched abductively at the point D, we should 

 have prescribed for the line A D the position R L, and the 

 electrical force at the point S would have assumed the negative 

 force indicated by V Y". The law of these changes is ob- 

 vious, and may be expressed generally thus : each place of a 

 galvanic circuit undergoes mediately, in regard to its outward- 

 ly acting electrical force, the same change which is produced 

 immediately at any other place of the circuit by external in- 

 fluences. 



Since each place of a galvanic cii'cuit undergoes, of itself, the 

 same change to which a single place was compelled, the change 

 in the quantity of electricity, extending over the whole circuit, is 

 proportional, on the one hand, to the sum of all the places, i. e. to 

 the space over which the electricity is diffused in the circuit, and 

 moreover, to the change in the electric force produced at one 

 of these places. From this simple law result the follow- 

 ing distinct phaenomena. If we call r the space over 

 which the electricity is diffused in the galvanic circuit, and 

 imagine this circuit touched at any one place by a non-con- 

 ducting body, and designate by u the electric force at this place 

 before contact, by u that after contact, the change produced 

 in the force at this place is u^ — u; consequently the change 

 of the whole quantity of electricity in the circuit is (wj — u) r. 

 If, now, we suppose that the electricity in the touched body is 

 diffused over the space R, and is at all places of equal strength, 

 and, at the same time, that at the place of contact itself the 

 circuit and the body possess the same electric force, viz. u, 

 it is evident u R will be the quantity of electricity imparted 

 the body, and 



{"i — ") r = uR, 

 whence we obtain ' 



