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the powers active in the acid are more free to act, produce a stronger 

 current, and effeci decomposition more freely. 



The chemical actions at the opposite ends of the metallic arrange- 

 ment are so strongly associated and related, that in the most perfect 

 form of experiment, action cannot occur at either end without also 

 taking place at the other extremity to an exactly equivalent amount. 

 This is considered by the author as the most convincing proof that in 

 the voltaic pile the chemical and electric action are the same ■ that is, 

 modes of exhibition of the same force, and as they are convertible 

 into each other in exactly definite proportion, must have one common 

 origin. 



By using different fluids at the exciting place of action, currents 

 of different, intensity could be obtained : thus the current produced 

 by the action of dilute sulphuric acid on zinc and platina could de- 

 compose elsewhere solution of iodide of potassium, fused protochloride 

 of tin, or chloride of silver ; but could not decompose water, muriatic 

 acid, nitric, or the chloride or iodide of lead. Making the dilute sul- 

 phuric acid stronger, or using larger plates of zinc and platina, did 

 not yield any advantage ; but immediately that the chemical action 

 on the zinc was increased in intensity, which could be done by adding 

 only a few drops of nitric acid, then most of the latter bodies could 

 be decomposed by a single pair of plates. A scale of initial intensities 

 can in this way be obtained. 



The electricity evolved in the voltaic pile is altogether due to that 

 chemical action which takes place between the metal most easily 

 acted upon and the element which unites with it ; as, for instance, 

 between the zinc and the oxygen of the water, or the chlorine of the 

 muriatic acid, or the sulphur of hydrosulphurets, &c. j the after action 

 of the acid in combining with the oxide, when that is the substance 

 formed, adds nothing to the effect. The truth of this principle is de- 

 duced in the first place from the electricity evolved being the equiva- 

 lent of the zinc oxidized ; in the second, from the quantity of elec- 

 tricity being the same for the oxidation of a given quantity of zinc, 

 whether the oxide formed is removed by an acid or an alkali and it 

 is supported by many other experimental reasons and proofs. 



The view which the author takes of the identity of electrical and 

 chemical action, leads him to admit that there are two modes of action 

 in which the attractive power of the substances which ultimately 

 combine, and by combining give the voltaic pile activity, can be ex- 

 erted. Thus, taking zinc and platina as the two metals used, then 

 the third substance must be an electrolyte ; that is, a body which is 

 decomposed when the electric current passes it; which cannot conduct 

 the current unless it is at the same time decomposed ; and which con- 

 tains an element having such attraction for the zinc that the latter 

 can take it from the element with which it is previously combined. 

 Water is the electrolyte generally present in the voltaic pile. 



Then, with respect to the attraction between the zinc and the 

 oxygen of the water, we have it in our power to cause it to take place 

 at once when the metal and water are in contact, the hydrogen being 

 then set free ; or we can, by using the precautions which the author 



