64 Proceedvigs of Philosophical Societies. [July, 



vu'eve;'5« where it touches an alkali; and the same is the caSe with 

 rhodium, iridium, and gold, the eftect being greater as the action of 

 the acid on the metal is greater. From this it follows, that when 

 a metal is in contact with an acid or alkali in one cup, and water 

 or a neutro-sahne solution in another, on completin<j the circuit, 

 the contact of the metal with the acid or alkali will determine 

 the character of the pole in contact with it, and that in contact 

 with the other fluid will of course be of the opposite name, and 

 this result is confirmed by experiment. In such combinations, 

 the chemical changes are such as might be expected ; oxygen 

 and the acids tending to circulate towards the negative surface, 

 and hydrogen and the alkalies towards the positive. 



In combinations consisting of two perfect conductors and one 

 fluid, the order in which the metals exhibit their electricities is 

 connected with their oxidability, the more oxidable metal being 

 positive with respect to all below it. It is not, however, any 

 inherent quality in the metals which determines this effect, but 

 their fitness for chemical action ; for if the state of aggregation 

 be altered, and the cohesive force, which always acts as an 

 antagonist force to chemical changes, be weakened, the posi- 

 tive energy is exalted in proportion : thus the amalgams of the 

 positive metals are positive with respect to the pure metals of 

 which they are amalgams. In general, the electricities deve- 

 loped by metaUic contact are too strong to be subverted by an 

 opposite action with the fluids with which both are in contact. 

 Such, however, is sometimes the case ; and in all instances, the 

 influence of the fluid is perceptible. 



The author next considers the accumulation of electricity, and 

 the chemical changes it produces in voltaic arrangements. 

 According to Volta's view of the action of the pile, the metals 

 were regarded as the only agents, and the chemical changes 

 arising in the fluids as mere results not essential to the develope- 

 ment of the electricity. This view, however, may be regarded 

 as altogether disproved by an experiment here described, in 

 which, when two glasses, filled with solution of nitrate of potash, 

 in which were plunged respectively zinc and platinum connected 

 by the multiplier, were connected by substances capable of 

 conducting electricity, but not of propagating chemical action, 

 such as unoxidable metals, the circulation of the current was 

 altogether destroyed. 



Since the chemical changes always tend to restore the equi- 

 librium, destroyed by the contact of the metals, in the fluids of 

 a pile, it is evident that the relation between the fluids them- 

 selves and the surfaces with which they are in contact, will be 

 altered by a continuance of the action of the pile. Hence it is 

 easy to perceive the possibility of a re-action taking place when 

 the' circuit is broken, or the disposition of the parts of a pile is 



