ns of perfect and imperfect
conductors, and is only transmitted by perfect conductors or imperfect
conductors of the best kind. Magnetism, if it be a form of
electricity, belongs only to perfect conductors; and, in its
modifications, to a peculiar class of them[1]. Animal electricity
resides only in the imperfect conductors forming the organs of living
animals, &c."

[1] Dr. Ritchie has shown this is not the case. Phil. Trans. 1832, p.
294.

[F] Phil. Trans. 1832, p. 259. Dr. Davy, in making experiments on the
torpedo, obtains effects the same as those produced by common and
voltaic electricity, and says that in its magnetic and chemical power
it does not seem to be essentially peculiar,--p. 274; but he then
says, p. 275, there are other points of difference; and after
referring to them, adds, "How are these differences to be explained?
Do they admit of explanation similar to that advanced by Mr. Cavendish
in his theory of the torpedo; or may we suppose, according to the
analogy of the solar ray, that the electrical power, whether excited
by the common machine, or by the voltaic battery, or by the torpedo,
is not a simple power, but a combination of powers, which may occur
variously associated, and produce all the varieties of electricity
with which we are acquainted?"

At p. 279 of the same volume of Transactions is Dr. Ritchie's paper,
from which the following are extracts: "Common electricity is diffused
over the surface of the metal;--voltaic electricity exists within the
metal. Free electricity is conducted over the surface of the thinnest
gold leaf as effectually as over a mass of metal having the same
surface;--voltaic electricity requires thickness of metal for its
conduction," p. 280: and again, "The supposed analogy between common and
voltaic electricity, which was so eagerly traced after the invention of
the pile, completely fails in this case, which was thought to afford the
most striking resemblance." p. 291.

266. Notwithstanding, therefore, the general impression of the identity of
electricities, it is evident that the proofs have not been sufficiently
clear and distinct to obtain the assent of all those who were competent to
consider the subject; and the question seemed to me very much in the
condition of that which Sir H. Davy solved so beautifully,--namely, whether
voltaic electricity in all cases merely eliminated, or did not in some
actually produce,