Faraday's Researches

metal, or rarefied air, or by means of points in common air,
is still able to deflect the needle; the only requisite being,
apparently, to allow time for its action: that it is, in fact, just
as magnetic in every respect as a voltaic current, and that in
this character therefore no distinction exists.
 44.	Imperfect conductors, as water, brine, acids, etc.., etc.,
will be found far more convenient for exhibiting these effects
than other modes of discharge, as by points or balls;  for the
former convert at once the charge of a powerful battery into
a feeble spark discharge, or rather continuous current, and
involve little or no risk of deranging the magnetism of the
needles (30).
 45.	iii. Chemical   decomposition.—The   chemical   action   of
voltaic electricity is characteristic of that agent, but not more
characteristic than are the laws under which the bodies evolved
by   decomposition  arrange   themselves   at   the   poles.     Dr.
Wollaston showedx that common electricity resembled it in
these effects, and " that they are both essentially the same; "
but he mingled with his proofs an experiment having a re-
semblance,, and nothing more, to a case of voltaic decomposi-
tion, which however he himself partly distinguished;  and this
has been more frequently referred to by some, on the one hand,
to prove the occurrence of electro-chemical decomposition, like
that of the pile, and by others to throw doubt upon the whole
paper, than the more numerous and decisive experiments which
he has detailed.
 46.	I take the liberty of describing briefly my results, and
of thus adding my testimony to that of Dr. Wollaston on the
identity of voltaic and common electricity as to chemical action,
not only that I may facilitate the repetition of the experiments,
but also lead to some new consequences respecting electro-
chemical decomposition (112, 113).

 47.	I   first   repeated   Wollaston's   fourth   experiment,2  in
which the ends of coated silver wires are immersed in a drop
of sulphate of copper.    By passing the electricity of the machine
through such an arrangement, that end in the drop which
received the electricity became coated with metallic copper.
One hundred turns of the machine produced an evident effect;
two hundred turns a very sensible one.    The decomposing
action was however very feeble.   Very little copper was pre-
cipitated., and no sensible trace of silver from the other pole
appeared in the solution.
1 Philosophical Transactions, 1801, pp. 427, 434.       2 Ibid. 1801, p. 429.