204	Faraday's Researches
the intensity at which the current ceased to act would be the
same for all bodies? and also whether the electrolytes thus
resisting decomposition would conduct the electric current as
a metal does, after they ceased to conduct as electrolytes, or
would act as perfect insulators ?
 702.	It was evident from the experiments described (639,
641) that different bodies were decomposed with very different
facilities, and apparently that they required for their decom-
position currents of different intensities, resisting some, but
giving way to others.   But it was needful, by very careful and
express experiments, to determine whether a current could
really pass through, and yet not decompose an electrolyte (645).
 703.	An arrangement (fig. 44) was made, in which two glass
vessels contained the same dilute sulphuric acid, sp. gr. 1.25.

Fig. 44.
The plate z was amalgamated zinc, in con-
nection, by a platina wire a, with the platina
plate e\ b was a platina wire connecting the
two platina plates P P'; c was a platina
wire connected with the platina plate P".
On the plate e was placed a piece of paper
moistened in solution of iodide of potas-
sium: the wire c was so curved that its
end could be made to rest at pleasure on
this paper, and show, by the evolution of
iodine there, whether a current was passing;
or, being placed in the dotted position, it
formed a direct communication with the
platina plate e} and the electricity could
pass without causing decomposition. The object was to produce
a current by the action of the acid on the amalgamated zinc
in the first vessel A; to pass it through the acid in the second
vessel B by platina electrodes, that its power of decomposing
water might, if existing, be observed; and^to verify the existence
of the current at pleasure, by decomposition at e} without involv-
ing the continual obstruction to the current which would arise
from making the decomposition there constant. The experiment,
being arranged, was examined and the existence of a current
ascertained by the decomposition at 0; the whole was then left
with an end of the wire c resting on the plate e> so as to form a
constant metallic communication there.
704.	After several hours, the end of the wire c was replaced
on the test paper at e:   decomposition occurred, and the proof
of a passing current was therefore complete.   The current was