e angular velocity. But they are forms of
expression which, being retained in the mind, I have found useful when
comparing the consistency of particular phenomena with general results.

_Royal Institution,
December 21, 1831._

THIRD SERIES.

S 7. _Identity of Electricities derived from different sources._ S 8.
_Relation by measure of common and voltaic Electricity._

[Read January 10th and 17th, 1833.]

S 7. _Identity of Electricities derived from different sources._

265. The progress of the electrical researches which I have had the honour
to present to the Royal Society, brought me to a point at which it was
essential for the further prosecution of my inquiries that no doubt should
remain of the identity or distinction of electricities excited by different
means. It is perfectly true that Cavendish[A], Wollaston[B], Colladon[C],
and others, have in succession removed some of the greatest objections to
the acknowledgement of the identity of common, animal and voltaic
electricity, and I believe that most philosophers consider these
electricities as really the same. But on the other hand it is also true,
that the accuracy of Wollaston's experiments has been denied[D]; and also
that one of them, which really is no proper proof of chemical decomposition
by common electricity (309. 327.), has been that selected by several
experimenters as the test of chemical action (336. 346.). It is a fact,
too, that many philosophers are still drawing distinctions between the
electricities from different sources; or at least doubting whether their
identity is proved. Sir Humphry Davy, for instance, in his paper on the
Torpedo[E], thought it probable that animal electricity would be found of a
peculiar kind; and referring to it, to common electricity, voltaic
electricity and magnetism, has said, "Distinctions might be established in
pursuing the various modifications or properties of electricity in those
different forms, &c." Indeed I need only refer to the last volume of the
Philosophical Transactions to show that the question is by no means
considered as settled[F].

[A] Phil. Trans. 1779, p. 196.

[B] Ibid. 1801, p. 434.

[C] Annnles de Chimie, 1826, p. 62, &c.

[D] Phil. Trans. 1832, p. 282, note.

[E] Phil. Trans. 1892, p. 17.

"Common electricity is excited upon non-conductors, and is readily
carried off by conductors and imperfect conductors. Voltaic
electricity is excited upon combinatio