ON SOME ELECTRICAJ, AND ELECTROCHEMICAL PHENOMENA. g]^ 



A. By the first, a positive surface may be employed to Different ef- 

 electrify another body positively, or negatively; or it ^ill ^'^"* °^ *^*^"' 

 electrify the same body at once positively, negatively, and 



neutral in different parts of its length ; but in this latter 

 case, the electrical efi'ects will last only during the approxi-' 

 mation. 



B. It is not possible to produce these effects of approxi* 

 mation, unless the bodies be separated by st. nonconductor^ 

 the resistance of which is sufficient to prevent thepassage of 

 electricity from one to the other. 



C. By the second method a positive surface can only 

 communicate positive electricity ; and vice versa. But 

 these communicated effects areperiwawen/ after the separation 

 of the bodies. 



D. The effects of communicated electricity can only 

 take place by the actual contact of conducting bodies, or 

 where the intervening medium does not completely resist the 

 passage of electricity. 



No two series of phenomena can I think be more distinct These tw© sets 



than the preceding ; their conditions of action are directly of phenomena 



•^ » ■' distinct, 



contrary, and it must be consequently obvious, the same 



explanation cannot apply to both, 



Mr. Davy has however for a long time applied the term Mr. Davy has 

 induction to some of these opposite cases of electrical action : ®PP''«.^ 'he 

 for instance, the Leyden jar, and the insulated rod ; dis- tionto both, 

 tinct cases of approximation : the spiral tube, luminous 

 word, electric spaik, &c., decisive instances of communis 

 cated electricity. 



In the Bakerian lecture for 1807, an explanation of the and attempted 

 voltaic battery was attempted on similar principles; and ^° ^'^P'^]", ^'''^ 

 this explanation has been repeated every succeeding season pile on the 

 in the lectures at the Royal Institution. It assumes, same principle. 

 *' that, with regard to electricity of such low intensity, 

 *« water is an iM5M/a/«H^ body." An assiimption, which has 

 beeu decisively contradicted by the experiments of Mr. de 

 Luc, which (irove, that the battery is z conducting column. 

 Yet Mr. Davy continues to speak of inductiont and electri- 

 cal polarity; and A. Z. appears to think it capable of ex-- 

 plaining the interrupted circuit; where the whole column is^ 

 indisputably £^ fojiductor, and where the phenomena depend 



