98 Prof. Majocchi on the On'gm of the Voltaic Cwretit. 



city by Volta's two dissimilar metals, to exclude any cause 

 foreign to that which arises from the contact of the two bodies. 

 Moreover, the period of thirty-three years, for which Prof. 

 Zamboni's dry pile has now existed, confirms such a mode of 

 electrical disturbance*. 



How then does electricity by contact take place ? Contact 

 is not a force ; it is the simple indication of the mode in which 

 metals arrange themselves in the case of the voltaic experi- 

 ment ; and no fluid whatever, the electric for instance, can be 

 put in motion without an agent. At the Turin Congress in 

 ISiO I expressed my opinion, that in the so-called contact, 

 although the action cannot be considered chemical, there is a 

 force of attraction which is the principle of the action itself, I 

 mean that force recognised and admitted by all, investigated 

 by many at the close of the last century and the beginning of 

 the present, that force, namely, which is called adhesion or 

 attraction of simple surfaces. I shall not repeat here what I 

 said on that occasionf ; but will rather observe, that such 

 facts have confirmed me in my opinion concerning the phoe- 

 nomenon of electricity in the fundamental experiments of 

 Volta. 



My purpose here is to examine the conditions necessary in 

 the pile to the generation of the current, which is quite di- 

 stinct from the simple electrical disturbance in the fundamental 

 experiments of Volta. In a circuit, in order to give birth to the 

 electric current, it is necessary that there should be two forces ; 

 one to emit the electric fluid in a given direction, the other to 

 carry it on from the place where it is lodged : these two forces 

 in Volta's pile are, — the one, adhesion, by which the direction 

 of the current is determined; the other, the chemical action 

 which takes place in electrolization, or in other terms, in the 

 decomposition of the intermediate liquid by which the electri- 

 city is evolved. It matters little whether this decomposition 

 is perceptible or imperceptible; since the polarization of two 

 platinum electrodes intended to complete the circuit with 

 the intermediate electrolyte, proves that, if there is no percep- 

 tible separation in the components of the liquid, there is an 

 imperceptible one; for the polarity of the electrodes them- 

 selves cannot happen without the decomposition of the liquid 

 in which they are immersed. The above-named conditions 

 are verified in any voltaic arrangement, both in the original 

 piles of Volta, and in those of Wollaston, Novellucci, Miche- 

 lotti, Daniell, Grove, Sec. In the fundamental experiments 



* See Annali, t. viii. p. 14. 



\ See the Annali, t. i. p. 45 ; and the Proceedings of the Second Meet- 

 ing of Italian Savans, p. 14. 



