On the Excitement of Voltaic Plates. 167 



their electrical energies, is sufficient to subvert the combina- 

 tion*. 



The experiments to wliich Mr. De Luc alhules, as particularly 

 affording a refutation of this hypothesis, are the third and tenth, 

 contained in the hrtst part of his analysis of the Galvanic pilef, 

 and to this paper I beg to refer your readers. Now, sir, I do 

 not think tliat the result of these experiments invalidates in the 

 sHghtest degree the hypothesis in question ; as a knowledge of 

 the general principle in eiectricity, which has been termed in- 

 duction or the laiv (if induction, will enable us to reconcile tiie 

 ."pparcnt disagreement. Upon this principle I will contend that 

 ':he electrical states of the points 1.2.3.4. were not such as 

 Mr. De Luc supposes, but that 1. and 3. must, under every va- 

 riety of the experiment, have been positive; 2. and 4. negative. 

 I am aware that the application of this law to the particular 

 case in (|uestion has been objected to. JNIr. Singer considers it 

 impossible for this law to operate, "unless the bodies he sepa- 

 rated by a non-conductor, the resistance of which is sufficient to 

 prevent the passage of electricity from one to the other J," and 

 therefore, that it is altogether inapplicable to the phaenomena of 

 the" interrupted circuit;" the objection toils application being, 

 that water is a conductor and incapable of affording such resist- 

 ance. The experiments of ivir. De Luc§, however, very plainly 

 demonstrate that there is such resistance in water as occasions a 

 retardation and residua of electricity; in other words, such a 

 resistance as prevents a free passage of electricity. That the 

 situation of bodies being such as to enable electricity to pass 

 from one to the other does not prevent tiie operation of this law, 

 is fully established bv the early experiments on the subject i| ; 

 and I will contend that it is as fairly applicable to the inter- 

 rupted circuit in Mr. De Luc's experiments, as to any phaeno- 

 mena of electricity: consequently I do not conceive that the 

 reasonings of Mr. Do Luc, founded on tiie result of liis third and 

 tenth experiments, are admissible; and I am inclined to consider 

 the arguments contained in my Essay, the first valid objections 

 opposed to Sir II. Davy's opinions on tlie subject of chemical 

 affinity and decomposition ; and, in fact, the first if not the only 

 refutation of tliem. 



Having stated the results of my experiments with the Voltaic 

 plates, I o!)scrved that they are subversive of the most coni- 

 inonlv received opinion of the manner in which a Voltaic pile is 

 excited, which originated in the pluenomena of these ))Iates, and 

 " rests on the assumption that dissimilar metals while in con-. 



* Phil. Trans. 1807. t I'liil. .luurnal, vol. xxvi. J Ibid. vol. xxxi. 



§ I'liil. Journal, vol. xxvi. ■ || bcc I'licsllc^'s H:tt. of Electricity, pt. i. 

 per. X. hccl. V. 



L 4 tact 



