On the Excitement of Fbllaic Plates. 169 



excitement of the ]y\\e, by supposing tlmt different metals ac- 

 quire a difference ot electrical state by contact, is not only un- 

 supported, but actually subverted by the phenomena of the Vol- 

 taic PLATES. 



In another instance, Mr. De Luc misapprehends in a most ex- 

 traordinary manner the tenor of my observations. " I filled," 

 *aid I, " one of the new porcelain troughs with an acid fluid, so 

 that the metallic plates and their connecting arcs were com- 

 pletely covered. In this state a trough of ten pairs of plates 

 three inches square decomposed water rapidly" — " I placed the 

 metals connected by the bar in a trough without partitions, and 

 no action en'ued*." The result of this experiment was to me 

 anomalous and unexpected. But Mr. De Luc has endeavoured 

 to ex})lain it, by taking as data, that ''•' when the plates were im- 

 mersed up to the bar in liquid," " the effect was reduced to that 

 of one single pairf ;" or, as J suppose, no perceptible action 

 ensued. By a reference however to the experiment, he will find 

 that such was the state of the apparatus when it decomposed 

 water rapidly. He has therefore misunderstood the statement 

 of the fact, but in no degree e.\ plained it J. 



1 indeed regret that Mr. De Luc has misunderstood any thing 

 that I have written; but I am altogether distressed at his ques- 

 tioning the accuracy of my experiments with the Voltaic plates; 

 ot indeed in consequence of having founded, as he supposes, a 

 Galvanic system" on them, which I am not aware of having- 

 "tempted, but because I value, above all other qualifications of 

 1 author, impartiality and fidelity in narration. Mr. De Luc 

 links some extraneous cause must have operated in my experi- 

 icnts, otherwise one single contact and separation of my plates 

 niild never have produced a sensible divergence of the gold- 

 ives : but he does not hint at any extraneous cause in particu- 

 lar, which he conceived likely to be the one ; — and as the ap- 

 paratus employed and the manner of performing the experi- 

 •nents were minutely described at the time the results were given, 

 ..ly extraneous cause attached either to the one or the other 

 iiiglit easilv have been detected and exposed. Mr. De Luc 

 'ates that in .M. Kafiy's experiments it required ten contacts 

 iiid separations of plates the size of mine before the gold-leaves 

 .ere sensibly affected. In tlie repetition which he made of these 

 experiments with smaller plates, it required twenty repetitions 

 liefore the effect on the g<jld-kavcs was visible. Now, sir, I 

 have expressed in my Essay, and so I wioh to be understood, 

 that a single contact and separation did not produce a sensible 



• Phil. Journal, vol. 3()(xi. f Ibid, vol. xxxiii. 



t I sliKiilil like 10 know whrtlicr tlie result of the experiment, as slated 

 ilj'jvf, hub bcfii ubluincd by other cxpcrniieutcrs, 



but 



