before and qfler completion of the Voltaic Circuit. 293 



22. Faraday*, in the course of that branch of his experi- 

 mental researches which introduced into notice the voltameter, 

 established the most accurate means of measuring the amount 

 of chemical action in the battery cells, by the equivalent 

 amount of chemical decomposition exhibited in that instru- 

 ment; he has also directed our attention to the fact, that this 

 amount of electro-chemical decomposition depends essentially 

 on the current as denoted by the galvanometer. There was 

 every reason, with these facts before us, to expect that the 

 battery, which did not produce a current, would not evince 

 any degree of chemical decomposition. Recourse was, how- 

 ever, had to the test of experiment ; and, instead of introdu- 

 cing the galvanometer, I substituted for it a small piece of 

 bibulous paper, saturated with a solution of iodide of potas- 

 sium ; the gold leaves of the electroscope diverged as before, 

 but, however long the duration of action, not the least indica- 

 tion of the liberation of iodine was perceptible. The infer- 

 ence I make from this is, that no definite chemical action took 

 place in any cell of the battery, and consequently that the 

 electric effects above shown, and which are termed static effects, 

 take place before or independently of the actual development of 

 the chemical effects. 



23. I am aware that, in some form or other, this fact has 

 been acknowledged by the most strenuous advocates of the 

 chemical theory. Becquerelf thus adverts to it : — " We must 

 conclude, from all the electrical phaenomena, that, in almost 

 all cases, a chemical action has taken place; and hence we 

 are led to believe that the latter is the cause which exercises 

 the greatest degree of influence over their production ; never- 

 theless, in the present condition of science, we must not yet 

 abandon Volta's theory, since it may very readily happen, 

 that, at the contact of two bodies, a disengagement of electri- 

 city may take place, resulting from a commencement of che- 

 mical action between these bodies." 



De la Rive I, who has laboured perhaps more than any of 

 the continental philosophers in advocating the chemical origin 

 of voltaic electricity, cannot but admit some such similar qua- 

 lification, as may be seen from the following extract from one 

 of his papers : — " The two theories between which philoso- 

 phers are divided with respect to the origin of voltaic electri- 

 city, are still the subject of lively controversy; when we are 

 adverting to the pile itself and to hydro-electric currents, we 

 cannot deny the superiority of the chemical theory; the recent 



• Experimental Researches, § 510. 



t Traite de V Elect., vol. ii. p. \Ab; vol. v. p. 3. 



X Archives de I' Electricity, vol. i. p. 619. 



