and it is probable for all cases, that the _chemical power, like the
magnetic force_ (36.), _is in direct proportion to the absolute quantity
of electricity_ which passes.

378. Hence arises still further confirmation, if any were required, of the
identity of common and voltaic electricity, and that the differences of
intensity and quantity are quite sufficient to account for what were
supposed to be their distinctive qualities.

379. The extension which the present investigations have enabled me to make
of the facts and views constituting the theory of electro-chemical
decomposition, will, with some other points of electrical doctrine, be
almost immediately submitted to the Royal Society in another series of
these Researches.

_Royal Institution,
15th Dec. 1832._

Note.--I am anxious, and am permitted, to add to this paper a correction of
an error which I have attributed to M. Ampere the first series of these
Experimental Researches. In referring to his experiment on the induction of
electrical currents (78.), I have called that a disc which I should have
called a circle or a ring. M. Ampere used a ring, or a very short cylinder
made of a narrow plate of copper bent into a circle, and he tells me that
by such an arrangement the motion is very readily obtained. I have not
doubted that M. Ampere obtained the motion he described; but merely mistook
the kind of mobile conductor used, and so far I described his _experiment_
erroneously.

In the same paragraph I have stated that M. Ampere says the disc turned "to
take a position of equilibrium exactly as the spiral itself would have
turned had it been free to move"; and further on I have said that my
results tended to invert the sense of the proposition "stated by M. Ampere,
_that a current of electricity tends to put the electricity of conductors
near which it passes in motion in the same direction._" M. Ampere tells me
in a letter which I have just received from him, that he carefully avoided,
when describing the experiment, any reference to the direction of the
induced current; and on looking at the passages he quotes to me, I find
that to be the case. I have therefore done him injustice in the above
statements, and am anxious to correct my error.

But that it may not be supposed I lightly wrote those passages, I will
briefly refer to my reasons for understanding them in the sense I did. At
first the experiment failed. When re-made successfully about a year
afterwa