Electrolytic Intensity 203

same direction by electro-chemical equivalents of hydrogen,
lead; copper,, and tin., at e, h, k, and m.

700. If the present paper be accepted as a correct expression
of facts, it will still only prove a confirmation of certain general
views put forth by Sir Humphry Davy in his Bakerian Lecture
for i8o6/ and revised and re-stated by him in another Bakerian
Lecture, on electrical and chemical changes, for the year i826.2
His general statement is, that " chemical and, electrical attractions
were produced by the same cause, acting in one case on particles,
in the other on masses, of matter ; and that the same property,
under different modifications, was the cause of all the phenomena
exhibited by different voltaic combinations" 3 This statement I
believe to be true; but in admitting and supporting it, I must
guard myself from being supposed to assent to all that is asso-
ciated with it in the two papers referred to, or as admitting the
experiments which are there quoted as decided proofs of the
truth of the principle. Had I thought them so, there would
have been no occasion for this investigation. It may be sup-
posed by some that I ought to go through these papers, distin-
guishing what I admit from what I reject, and giving good
experimental or philosophical reasons for the judgment in both
cases. But then I should be equally bound to review, for the
same purpose, all that has been written both for and against
the necessity of metallic contact,—for and against the origin
of voltaic electricity in chemical action,—a duty which I may
not undertake in the present paper.4

^f ii. On the Intensity necessary for Electrolysation

701. It became requisite, for the comprehension of many of
the conditions attending voltaic action, to determine positively,
if possible, whether ejectrolytes could resist the action of an
electric current when beneath a certain intensity? whether

1 Philosophical Transactions, 1807. 2 Ibid. 1826, p. 383.

3 Ibid. 1826, p. 389.

4 I at one time intended to introduce here, in the form of a note, a table
of reference to the papers of the different philosophers who have referred
the origin of the electricity in the voltaic pile to contact, or to chemical
action, or to both; but on the publication of the first volume of M.
Becquerel's highly important and valuable Traite de VElectricite et du
Magnetism, I thought it far better to refer to that work for these references,
and the views held by the authors quoted. See pages 86, 91, 104, no, 112,
117, 118, 120, 151, 152, 224, 227, 228, 232/233, 252, 255, 257, 258, 290,
etc.—July 3, 1834.ts of iodine at I; and in theing part of an electrolyte, or formingernd then