231 



ON A NEW VOLTAIC COMBINATION. 



Phil. Mag., 1839.* 



MR. PoRRETT was, I believe, the first who employed a blad- 

 der to separate the liquids in the operating cell of the voltaic 

 pile. M. Becquerel, by introducing this into the exciting 

 cells, has shown us how to render constant the primitive in- 

 tensity of the battery by preventing cross precipitation ; Mr. 

 Daniell has remedied some practical defects in M. Becquerel's 

 arrangement, and his form of battery is undoubtedly the best 

 of any that have been hitherto proposed. 



In a letter published in the ' Philosophical Magazine ' for 

 February I endeavoured to show, that in addition to the im- 

 mense benefit derived from constancy of action, which was the 

 object aime<4 at by these gentlemen, the combination of four 

 elements was capable of producing a much more powerful 

 development of electricity than that of three, as by this means 

 we have nearly the sum of chemical affinities instead of their 

 difference ; I also there suggested that if the principles I had 

 laid down were true, there was every probability of superior 

 combinations being discovered. I have lately been fortunate 

 enough to hit upon a combination which I have no hesitation 

 in pronouncing much more powerful than any previously 

 known. The experiments which led to it are curious, and 

 possess an interest of their own, as they prove a well-known 

 chemical phenomenon to depend upon electricity, and thus 

 tighten the link which binds these two sciences. The effect to 

 which I allude is the dissolution of gold in nitro-muriatic acid ; 

 this metal, as is well known, not being attacked by either of 

 the acids singly. The following experiments leave, I think, 

 no doubt as to the rationale of this phenomenon : 



* From the Comptes Rendus, Academic des Sciences, Paris, 



