Mr. J. Prideaux on the Tlieory of Voltaic Action. 259 



not recollect to have encountered elsewhere, is in point here, 

 and compares well with the stimulative action of the electric 

 state of the liquid (20). 



If a large and a small plate of zinc connected through a 

 multiplier be plunged into a weakly acid liquor, the larger acts 

 as copper ; but increase the acidity, or warm the liquid, the 

 larger acts as zinc. 



Here when the acid is too weak to attack the zinc, the 

 larger surface giving the greater field for the influence of the 

 negative liquor, positive electricity sets away from it (20) 

 through the wire, to the smaller plate, as happens with cop- 

 per. But when the metal is acted on, either by increasing the 

 acidity, or warming the liquor, the larger surface gives off the 

 more positive electricity to the liquor, which then sets through 

 the wire in the other direction, as in the case of zinc; thus 

 not only compensating, but surpassing (42), the negative sti- 

 mulation of the acid first demonstrated. 



It must here be confessed, that my results in repeating this 

 experiment have not been constant, though generally confir- 

 matory. The authority of Berzelius is, nevertheless, abun- 

 dantly sufficient ; and proofs of the efficacy of chemical action, 

 in augmenting the voltaic current, are too familiar to the ex- 

 perimentalist to need further exemplification here. 



Conclusion. 



The theory here advocated may be thus generally stated. 



When zinc and copper come into contact, positive electri- 

 city passes from the copper into the zinc, until their mutual 

 relation to that fluid be in equilibrio : this is initial electro- 

 motion ; which may be continued, in the condition of circula- 

 tion, through a conducting liquid (12). But if an electro- 

 positive liquid be placed in contact with the negative metal, 

 and vice versa, and the circulation kept up, the disposition of 

 the liquids being in counteraction to that of the metals, the 

 electro-motive action is obstructed (19). On the contrary, 

 when the positive and negative liquids are in contact with the 

 homo-electric metals, the tendency of the whole is in the same 

 direction, and the electro-motive action is expedited (19). 



When the electricity thus passes into the zinc, and on into 

 the positive element of the liquid, the so charged liquid particle 

 is repelled, and attracted by the copper, in proportion to the 

 approximation of the plates ; and having free motion, proceeds 

 in that direction with proportionate velocity. The converse 

 takes place between the copper and the electro-negative liquid 

 particle; and the particles discharging themselves on their 

 arrival, thus maintain the circulation. 



2 L 2 



