THE 

 LONDON ANB EDINBURGH 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE, 



SUPPLEMENT to VOL. XVL THIRD SERIES. 



LXXXIII. On Galvanic Circuits composed of two Fluids, and 

 of two Metals not in contact. By Professor J. C. Poggen- 



DORFF.* 



[Continued from p. 498, and concluded.] 



Vl^ITH all combinations in which zinc, iron, or tin forms the 

 ' " positive metal, even with some in which amalgamated 

 zinc occupies that place, the water has the ascendency over the 

 (dilute) hydrochloric acid, as already observed by Fechner with 

 the combination zinc-copper in a somewhat more complex ex- 

 periment, his experimentum crucisf. 



But water also exhibits this ascendency, in the greater num- 

 ber of cases, over sulphuric acid J; with the combinations zinc- 

 platina, zinc-tin even more strongly than over hydrochloric acid, 

 exceedingly strong, especially with amalgamated zinc and re- 

 cently heated platina. And yet sulphuric acid is no electrolyte. 



Nor is nitric acid an electrolyte, and nevertheless it so alters 

 the electromotive force that with zinc-platina it has the ascend- 

 ency over water, but in the other combinations with zinc and 

 tin as positive member it succumbs to it. 



Similarly circumstanced is ammonia, which is likewise no 

 electrolyte. In all combinations with iron and tin as positive 

 member, it always succumbs to water ; in those with zinc, amal- 

 gamated or pure, it has on the contrary (copper excepted) gene- 

 rally the ascendency. 



Solution of chlorine affords a similar example. The differ- 

 ence of its action from water and from hydrochloric acid is suffi- 

 ciently evident from the table ; and yet it can hardly be classed 

 among the electrolytes. 



The assertion of Vorsselman de Heer that only electrolytes 

 are capable of changing the electromotive force, is therefore cer- 

 tainly incorrect. 



* From Poggendorff's Aiinalen, vol. xlix, January, 1840 : translated by 

 Mr. W. Francis. 



t Lond. and Edinb. Phil. Mag., vol. xiii. p. 374. 



X As I have already sho wn, although less distinctly, in another way for the 

 zinc-copper circuit. Annalen, vol. xlv. p. 405. 



Phil. Mag. S. 3. Vol. 16. No, 106. Siippl. July 1840. 2 O 



