tion,
oxygen, chlorine, iodine, acids, &c., are rendered at its negative
extremity, and combustibles, metals, alkalies, bases, &c., at its positive
extremity (467.), I do not believe that a substance can be transferred in
the electric current beyond the point where it ceases to find particles
with which it can combine; and I may refer to the experiments made in air
(465.) and in water (495.), already quoted, for facts illustrating these
views in the first instance; to which I will now add others.

525. In order to show the dependence of the decomposition and transfer of
elements upon the chemical affinity of the substances present, experiments
were made upon sulphuric acid in the following manner. Dilute sulphuric
acid was prepared: its specific gravity was 1.0212. A solution of sulphate
of soda was also prepared, of such strength that a measure of it contained
exactly as much sulphuric acid as an equal measure of the diluted acid just
referred to. A solution of pure soda, and another of pure ammonia, were
likewise prepared, of such strengths that a measure of either should be
exactly neutralized by a measure of the prepared sulphuric acid.

526. Four glass cups were then arranged, as in fig. 55; seventeen measures
of the free sulphuric acid (525.) were put into each of the vessels _a_ and
_b_, and seventeen measures of the solution of sulphate of soda into each
of the vessels A and B. Asbestus, which had been well-washed in acid, acted
upon by the voltaic pile, well-washed in water, and dried by pressure, was
used to connect _a_ with _b_ and A with B, the portions being as equal as
they could be made in quantity, and cut as short as was consistent with
their performing the part of effectual communications, _b_ and A were
connected by two platina plates or poles soldered to the extremities of one
wire, and the cups _a_ and B were by similar platina plates connected with
a voltaic battery of forty pairs of plates four inches square, that in _a_
being connected with the negative, and that in B with the positive pole.
The battery, which was not powerfully charged, was retained in
communication above half an hour. In this manner it was certain that the
same electric current had passed through _a b_ and A B, and that in each
instance the same quantity and strength of acid had been submitted to its
action, but in one case merely dissolved in water, and in the other
dissolved and also combined with an alkali.

527. On breakin