ON THE GALVANIC PHENOMENA. J 43 



have met a fatal objection to that part of his theory, which 



gives all to the metals and nothing to the fluids, in * Mr. Davy's galvanic 



Davy's galvanic pile, conlifling of one metal throughout, but kind of meta j 



with different ftrata of fluids : for example thus ; metal, cloth only and three 



foaked in dilute nitrous acid, cloth foaked in water, cloth 



foaked in fulphuret of potafh ; — then the fame metal, and 



nitrous acid, and water, and fulphuret; — the metal, &c. 



Or if a trough be ufed, the feparation between the acid and Trough of the 



fulphuret may be made by a plate of horn, and the two fluids tion< 



may be connected by a flip of wetted paper hung over the 



edge of the horn, which will not caufe the fluids to mix,' be- 



caufe water is lighter than either. The metals, feparately 



and fuccefsfully tried, were filver, copper, zinc, and lead. 



To this 1 will here add, from converfation, an experiment Electric current 

 of the fame philofopher, which is no lefs conclufive as to the ° iIe Overfed by 

 direct efficacy of the fluid in this apparatus ; becaufe the fame changing the 

 electric power is made to move either from the top or bottom 

 of a pile of two metals, according to the nature of the inter- 

 pofed fluid. — If a pile of copper and iron be conflructed as 

 ufual, with water interpofed, the iron becomes electrified 

 plus and the copper minus ; but if the fame, or a fimilar pile,, 

 be conftructed with no other difference than that fulphuret of 

 potafh is ufed inftead of water, the iron is electrified- minus 

 and the copper plus. In the firft cafe the iron is oxided ; 

 but in the fecond there is no oxidation of this metal, and the 

 copper is oxided, and probably fulphurated. 



Laflly, we have another inflance of the power and im- Galvanic feries 

 portance of the fluids in the article which follows the prefent, ^ftwTflutdsf 

 where charcoal alone is ufed, and the leading condition is, 

 that two different fluids mall be ufed. 



As we know by the experiments of De Sauflure, and many Chemical 

 others, that chemical changes do diflurb the equilibrium f5 han S esarc 



i rv • • i i -ii i • -i known to pro- 



electricity, and they certainly take place in the pile, it lecms duce elearicity ; 

 at leaft probable that thefe may have the chief agency in and as fucn 

 the apparatus. With regard to the principle of electric /^ th^pile^they 

 motors of Sig. Volta, I mufl obferve, that Bennet made many may probably 

 dired experiments of applying different metals, by the Angle "" f ' itS eledrI * 



* See notice in the Scientific News, Phil. Journal, 4to. for : 

 May, J 801, Vol. V. p. 78 ; and the fubjeft is fully treated in the 

 Philof. Tranf. for 1801, in a paper inferted in the fame volume of 

 our Journal, 4to. p. 341. 



and 



