Two Fluids, and of Two Metals not in Contact, 549 
cuits composed of acid, iodide of potassium, amalgamated and 
non-amalgamated zinc. 
As evident from the Table, the current has in these circuits, 
on employing pure sulphuric acid or hydrochloric acid in the 
diluted state, after a first deflexion in the direction s ^i, the 
direction s^ i with great energy, or the acid the ascendency 
over the iodide of potassium. The same is the case, and indeed 
without the first deflexion s <i, when sulphuric acid containing 
nitric acid or pure concentrated hydrochloric acid (spec. gr. 
1’138) is employed. — In all these cases, therefore, the non-amaU 
gamated zinc acts as a negative metal, for instance like silver, 
towards the amalgamated ; and yet it is always attacked far more 
energetically than the latter ; by the concentrated hydrochloric 
acid, indeed, with a truly stormy violence. How can this be 
explained in a satisfactory manner according to the chemical 
theory ? 
I say in a satisfactory manner ; for the explanation which 
Faraday has given of the cause of the positiveness or greater 
activity of the amalgamated zinc in comparison with the un- 
amalgamated, — namely, that the latter, being directly attacked 
by the acids, neutralizes them by the oxide it produces, and 
thus retards the progress of oxidation, whilst at the surface of 
the amalgamated zinc the oxide formed is instantly removed by 
the free acid present, and the clean metallic surface is always 
ready to act with full energy upon the water*, — can scarcely be 
termed satisfactory, as it is in open contradiction to experience, 
which shows that under like circumstances by far more of the 
unamalgamated than of the amalgamated zinc is dissolved. 
Just as little can the doctrine of local and circulating chemi- 
cal forces, and the assumption that the latter are produced in 
greater energy or quantity by the amalgamated zinc than by the 
unamalgamatedt^ be admitted here, or generally, as valid. This 
doctrine possesses, it is true, such pliancy, that by it all the nu- 
merous cases, where, as in the experiment of Berzelius (p. 486.), 
the negative metal is more violently attacked than the positive, 
may be set aside, with the explanation that it is effected by a 
local action which adds nothing to the current ; but, on a closer 
view, it is nothing more than a gratuitous hypothesis, which 
the chemical theory finds itself compelled to adopt in order 
not most palpably to fall into a contradiction with the fact, that 
the energy of the electromotive force no ways corresponds to 
the violence of the attack on the zinc or positive metal. Where 
is there any proof of this ? It is as much in w'ant of one, as 
^ Exp. Res. § 1005. 
t Exp. Res. §§ 947, 996, 1120, 
