OHM ON THE GALVANIC CIRCUIT. 44? 



entire force is situated immediately at the surface, which inva- 

 riably happens when it has entered into equilibrium ; and 

 thence, therefore, it happens that the atmosphere exerts no 

 perceptible influence on galvanic phaenomena in the closed 

 circuit when this is composed of good conductors, so that the 

 changes produced by the presence of the atmosphere in phae- 

 nomena of contact-electricity may be neglected in such cases. 

 This conclusion, moreover, receives new support from the cir- 

 cumstance, that in the same cases the contact-electricity only 

 remains during an exceedingly short time in the conductors, 

 and even on that account would only give up a very sUght por- 

 tion to the air, even if it were in immediate contact with it. 



Although, from what has been stated, it is placed beyond all 

 doubt that the action of the atmosphere has no perceptible in- 

 fluence on the magnitude of effect of the usual galvanic circuits, 

 it by no means is intended to admit the reverse of the conclu- 

 sion, viz. that the galvanic conductor exerts no perceptible in- 

 fluence on the electric state of the atmosphere ; for mathema- 

 tical investigation teaches us that the electroscopic action of a 

 body on another has no direct connexion with the quantity of 

 electricity which is carried over from the one to the other. 



10. We arrive at last at that position founded on experi- 

 ment, and which is of the highest importance for the whole of 

 natural philosophy, since it forms the basis of all the phjeno- 

 mena to which we apply the name of galvanic : it may be ex- 

 pressed thus: Different bodies, which touch each other, con- 

 stantly preserve at the place of contact the same difference be- 

 tween their electroscopic forces by virtue of a contrariety pro- 

 ceeding from their nature, which we are accustomed to desig- 

 nate by the expression electric tension, or difference of bodies. 

 Thus enounced, the position stands, without losing any of its 

 simplicity, in all the generality which belongs to it ; for we are 

 nearly always referred to it by every single phEenomenon. 

 Moreover, the above expression is adopted in all its generahty, 

 either expressly or tacitly, by all philosophers in the explana- 

 tion of the electroscopic phaenomena of the voltaic pile. Ac- 

 cording to our previously developed ideas respecting the mode 

 in which elements act on one another, we must seek for the source 

 of this phaenomenon in the elements directly in contact, and con- 

 sequently we must allow the abrupt transition to take place from 

 one body to the other in an infinitely small extent of space. 



