Definite Action with Varying Electrodes

hermetically at the part held in the stand,, is five inches in
length, and 0.6 of an inch in diameter; the neck about nine
inches in length,, and 04 of an inch in diameter internally.
The figure will fully indicate the construction.

447. It can hardly be requisite to remark, that in the arrange-
ment of any of these forms of apparatus, they, and the wires
connecting them with the substance, which is collaterally sub-
jected to the action of the same electric current, should be so far
insulated as to ensure a certainty that all the electricity which
passes through the one shall also be transmitted through the
other.

Fig 25.

Fig. 26.

448. Next to the precaution of collecting the gases, if mingled,,
out of contact with the platinum, was the necessity of testing
the law of a definite electrolytic action, upon water at least, under
all varieties of condition; that, with a conviction of its certainty,
might also be obtained a knowledge of those interfering circum-
stances which would require to be practically guarded against.

449. The first point investigated was the influenc • or indif-
ference of extensive variations in the size of the electrodes, for
which purpose instruments like those last described (444, 445,
446) were used. One of these had plates 0.7 of an inch wide,
and nearly four inches long; another had plates only 0.5 of an
inch wide, and 0.8 of an inch long; a third had wires 0.02 of an
inch in diameter, and three inches long; and a fourth, similar
wires only half an inch in length. Yet when these were filled
with dilute sulphuric acid, and, being placed in succession, had
one common current of electricity passed through them, very
nearly the same quantity of gas was evolved in all. The
difference was sometimes in favour of one, and sometimes on were to be collected. It is fixed on