ELECTRO-CHEMICAL PRINCIPLES, 



161 



disappearing as caloric, and re-appearing in the electric state 

 restored to the separate elements. 



If the chemical affinity be nothing more than the result of ^ a F ^ f e "£ 

 the polarity of the particles, it will follow decidedly, that it p ii ea renot 

 cannot be affinity which is the first mover, and causes the c ^ sc : d *T 

 electric phenomena; but that on the contrary, the play of chemi- 

 cal affinities in the pile must be a consequence of these last : 

 And this opinion is accordingly confirmed by experiment.* 

 [Annotation. See remark at the note on page 154.] 



* I was long of opinion that the oxidation of the zinc in the 



electric pile, was the cause of the change of electricity, aad I Experiment to 



endeavoured to prove that this hypothesis was sufficient to ex- ^j™ **' * iC 



plain the phenomena of the pile (See my Theory of the chemical 



Electric Pile in the " Neues Allgemeines Journal der Chemie/' f ct JV n \°* «. 



° bodies do not 



by Gehlen, in the year I8O7.) But the experiments of Davy produce that 



and Pfaff, having rendered my opinions less probable, I endea- phenomena. 



voured to convince myself of the truth, by an experiment 



which I think decisive. I took 12 tubes of glass, half an inch 



in diameter and three inches in height, and closed at one end, I 



half filled them with a strong solution of the submuriate of 



lime (such as is obtained by the residue after the preparation of 



caustic ammonia) and above this fluid I poured diluted nitric 



acid, with the precaution net to mix the liquids. I ranged 



these tubes in succession, and then took copper wires, round one By a row of 



of the extremities of each of which I had melted zinc, iu^^madeiu 



order to attach a knob of that metal to that end. I immersed which the 



the zinc-coated ends of each into one of the tubes to the bottom pg/^iJ^ ^{J" 



of the submuriat,and then bended the upper ends of the respec- muriate of 



tive wires, so as to immerse them into the middle of the acid of llI ?f' n,tnc 



acid ; copper, 



each nearest tube. This arrangement, consequently, formed a &c While 



pile in the order following : copper, zinc, submuriate of lime, the , extreme 

 r ° rr ' poles were 



nitric acid ; copper, zinc, &c. it is evident that the chemical unconnected, 



affinity which produces oxidation at the common temperature, the nitric acid 



1 1 ' r r 1 r , T. . dissolved the 



was here at the surtace of that part of the copper, which was C upper,andthe 



in. contact with the nitric acid ; and that if this oxidation had submuriate 



been the primary cause of the electricity of the pile, the pole on t h e zinc. 



of copper in this construction ought to have possessed the same If oxidation 



electricity (namely the positive) as the zinc pule in the common f positive"^ 



pile. Before the poles, or extremes, of this small pile were the copper 



connected, the copper continued to be constantly dissolved in the J'^ e been* 



acid, 



