362 ELECTRO-CHEMICAL PRINCIPLES. 



acid, which it turned blue, and the surface of the zinc remained 



metallic and without any perceptible change. And lastly, I 



combined the poles by means of silver wires, passed into a tube 



filled with a solution of muriate of soda. But I was greatly 



but when the surprised to find the effect directly contrary to what the theory 



were^olned* 16 * wl]icl1 consitlers oxidation as the cause of the electiicity of the 



the action in pile had led me to expect. The solution of the copper instantly 



butantit re* cease( *and the z,n c became covered with a mass of white oxide, 



versed. The vegetating on all sides in the form of wool. The pole of the 



oxklecPthe 1 ' 611 C0 PP er produced hydrogen gas as usual, and the zinc pole caus- 



copper ceased e d an abundant precipitate of muriate of silver. The electric 



f° d b ?w h>£ ° l , ved state - therefore, produced in this case an affinity, which, at the 



©nthezincside ordinary temperature of the atmosphere is inactive, and caused 



was positive as another very active affinity to cease, which was already in 



operation -, and this could be effected by no other cause than 



the eTect. was *kat °^ ^ ie electricity produced by contact, which occasions the 



not therefore electric charga of the pile, and disposes the affinities which shall 



fhe action of ^ e P ut into *#**'$?• This little electric pile, was very powerful, 



the ordinary and disengaged so large a quantity of gas, as would not have 



aSaity been excee ded by 100 pair of plates. But what could be the 



cause of this ? — I exchanged the submuriate for neutral muriate j 



Changes in the it then produced a very moderate effect, corresponding with the 



Ijqmd*. number of pairs j and lastly, I substituted neutral muriate of 



zinc instead of the muriate of lime, and then the effect was 



scarcely perceptible, though it continued sufficient to prevent 



the oxidation of the copper in the nitric acid, and to shew that 



the conduct or of the zinc pole continued always to be oxided. It 



appears, therefore, that the activity of the pile depends on the 



liquid substance, which during the process must change place j 



and that the most advantageous construction of a pile is copper, 



zinc, alkaline substance, acid, copper, zinc, &c. The pile 



will continue active untii the order becomes inverted, that is to 



say, copper, zinc, acid, alkali, &c. This experiment also 



proves how necessary it is in every' theory of the pile to attend 



to the chemical effect which must take place in the liquid. 



[Here the Annotation ends.] 



The electricity The connection between chemical affinity and the electric 



excited in the state, is also such, that upon every occasion wherein the effect of 



by e aftmi r ty tC to th e electricities, excited by contact, cannot take place, the 



great distance*, affinity acts only at a distance, infinitely small and impossible :o 



te 



