208 Faraday's Researches

stance than for the iodide of potassium in a similar state of
solution.

713. I then experimented on bodies rendered decomposable
by fusion, and first on chloride of lead. The current was excited
by dilute sulphuric acid without any nitric acid between zinc
and platina plates, fig. 47, and was then made to traverse a
little chloride of lead fused upon glass at a, a paper moistened
in solution of iodide of potassium at b, and a galvanometer at g.
The metallic terminations at a and b were of platina. Being
thus arranged, the decomposition at b and the deflection at g
showed that an electric current was passing, but there was no
appearance of decomposition at a, not even after a metallic
communication at b was established. The experiment was re-
peated several times,, and I am led to conclude that in this case
the current has not intensity sufficient to cause the decom-
position of the chloride of lead; and further, that, like water
(709), fused chloride of lead can conduct an electric current
having an intensity below that required to effect decom-
position.

714. Chloride of silver was then placed at a, fig. 47, instead
of chloride of lead. There was a very ready decomposition of
the solution of iodide of potassium at b, and when metallic
contact was made there,, very considerable deflection of the
galvanometer needle at g. Platina also appeared to be dissolved
at the anode of the fused chloride at a, and there was every
appearance of a decomposition having been effected there.

715. A further proof of decomposition was obtained in the
following manner. The platina wires in the fused chloride at
a were brought very near together (metallic contact having been
established at b)} and left so; the deflection at the galvanometer
indicated the passage of a current, feeble in its force, but
constant. After a minute or two, however, the needle would
suddenly be violently affected, and indicate a current as strong
as if metallic contact had taken place at a. This I actually
found to be the case, for the silver reduced by the action of the
current crystallised in long delicate spiculse, and these at last
completed the metallic communication; and at the same time
that they transmitted a more powerful current than the fused
chloride, they proved that electro-chemical decomposition of
that chloride had been going on. Hence it appears that the
current excited by dilute sulphuric acid between zinc and platina
has an intensity above that required to electrolyse the fused
chloride of silver when placed between platina electrodes,52, 255, 257, 258, 290,