t of
which has before been adverted to (1006.). But their interest is not
perhaps sufficient to justify any increase of the length of this paper,
which is rather intended to be an investigation of the theory of the
voltaic pile than a particular account of its practical application[A].

[A] For further practical results relating to these points of the
philosophy of the voltaic battery, see Series X. S 17.
1163.--1160.--_Dec. 1838._

_Note_.--Many of the views and experiments in this Series of my
Experimental Researches will be seen at once to be corrections and
extensions of the theory of electro-chemical decomposition, given in the
Fifth and Seventh Series of these Researches. The expressions I would now
alter are those which concern the independence of the evolved elements in
relation to the poles or electrodes, and the reference of their evolution
to powers entirely internal (524. 537. 661.). The present paper fully shows
my present views; and I would refer to paragraphs 891. 904. 910. 917. 918.
947. 963. 1007. 1031. &c., as stating what they are. I hope this note will
be considered as sufficient in the way of correction at present; for I
would rather defer revising the whole theory of electro-chemical
decomposition until I can obtain clearer views of the way in which the
power under consideration can appear at one time as associated with
particles giving them their chemical attraction, and at another as free
electricity (493. 957.).--M.F.

_Royal Institution,
March 31st, 1834._

NINTH SERIES.

S 15. _On the influence by induction of an Electric Current on itself:--and
on the inductive action of Electric Currents generally._

Received December 18, 1834,--Read January 29, 1835.

1048. The following investigations relate to a very remarkable inductive
action of electric currents, or of the different parts of the same current
(74.), and indicate an immediate connexion between such inductive action
and the direct transmission of electricity through conducting bodies, or
even that exhibited in the form of a spark.

1049. The inquiry arose out of a fact communicated to me by Mr. Jenkin,
which is as follows. If an ordinary wire of short length be used as the
medium of communication between the two plates of an electromotor
consisting of a single pair of metals, no management will enable the
experimenter to obtain an electric shock from this wire; but if the wire
which surrounds an electro-magnet be