ive a
current at all comparable to that of a single unobstructed pair.

1017. I have already said that a _very feeble current_ passed when the
series included one interposed platina and two pairs of zinc and platina
plates (1012.). A similarly feeble current passed in every case, and even
when only one exciting pair and four intervening platina plates were used,
fig. 98, a current passed which could be detected at _x_, both by chemical
action on the solution of iodide of potassium, and by the galvanometer.
This current I believe to be due to electricity reduced in intensity below
the point requisite for the decomposition of water (970. 984.); for water
can conduct electricity of such low intensity by the same kind of power
which it possesses in common with metals and charcoal, though it cannot
conduct electricity of higher intensity without suffering decomposition,
and then opposing a new force consequent thereon. With an electric current
of, or under this intensity, it is probable that increasing the number of
interposed platina plates would not involve an increased difficulty of
conduction.

1018. In order to obtain an idea of the additional interfering power of
each added platina plate, six voltaic pairs and four intervening platinas
were arranged as in fig. 99; a very feeble current then passed (985.
1017.). When one of the platinas was removed so that three intervened, a
current somewhat stronger passed. With two intervening platinas a still
stronger current passed; and with only one intervening platina a very fair
current was obtained. But the effect of the successive plates, taken in the
order of their interposition, was very different, as might be expected; for
the first retarded the current more powerfully than the second, and the
second more than the third.

1019. In these experiments both amalgamated and unamalgamated zinc were
used, but the results generally were the same.

1020. The effects of retardation just described were altered altogether
when changes were made in the _nature of the liquid_ used between the
plates, either in what may be called the _exciting_ or the _retarding_
cells. Thus, retaining the exciting force the same, by still using pure
dilute sulphuric acid for that purpose, if a little nitric acid were added
to the liquid in the _retarding_ cells, then the transmission of the
current was very much facilitated. For instance, in the experiment with one
pair of exciting plates and one inte