THE 
LONDON AND EDINBURGH 
PHILOSOPHICAL MAGAZINE 
AND 
JOURNAL OF SCIENCE, 
SUPPLEMENT to VOL. XVI. THIRD SERIES. 
LXXXIIL On Galvanic Circuits composed of two Fluids, and 
of two Metals not in contact. By Professor J. C, Poggen- 
^ DORFF.* 
[Continued from p. 4Q8, and concluded.] 
XTriTH 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 ewperimentum crucis\. 
But water also exhibits this ascendency, in the greater num- 
ber of cases, over sulphuric acid { ; 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 Annalen, vol. xlix. January, 1840: translated by 
Mr. W. Francis. 
t Lond. and Edinb. Phik 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, Maa. S, 3. Vol. 16. No. 106. Suppl, 2 O 
A 
