same
whether it be pure, or rendered a better conductor by the addition of these
substances; and that for currents of less intensity than this, the water,
whether pure or acidulated, has equal conducting power. An apparatus, fig.
84, was arranged with dilute sulphuric acid in the vessel A, and pure
distilled water in the vessel B. By the decomposition at _c_, it appeared
as if water was a _better_ conductor than dilute sulphuric acid for a
current of such low intensity as to cause no decomposition. I am inclined,
however, to attribute this apparent superiority of water to variations in
that peculiar condition of the platina electrodes which is referred to
further on in this Series (1040.), and which is assumed, as far as I can
judge, to a greater degree in dilute sulphuric acid than in pure water. The
power therefore, of acids, alkalies, salts, and other bodies in solution,
to increase conducting power, appears to hold good only in those cases
where the electrolyte subject to the current suffers decomposition, and
loses all influence when the current transmitted has too low an intensity
to affect chemical change. It is probable that the ordinary conducting
power of an electrolyte in the solid state (419.) is the same as that which
it possesses in the fluid state for currents, the tension of which is
beneath the due electrolytic intensity.

985. Currents of electricity, produced by less than eight or ten series of
voltaic elements, can be reduced to that intensity at which water can
conduct them without suffering decomposition, by causing them to pass
through three or four vessels in which water shall be successively
interposed between platina surfaces. The principles of interference upon
which this effect depends, will be described hereafter (1009. 1018.), but
the effect may be useful in obtaining currents of standard intensity, and
is probably applicable to batteries of any number of pairs of plates.

986. As there appears every reason to expect that all electrolytes will be
found subject to the law which requires an electric current of a certain
intensity for their decomposition, but that they will differ from each
other in the degree of intensity required, it will be desirable hereafter
to arrange them in a table, in the order of their electrolytic intensities.
Investigations on this point must, however, be very much extended, and
include many more bodies than have been here mentioned before such a table
can be cons