rated from the battery, washed in distilled water, and
introduced through the water of the pneumatic trough into a tube containing
the mixture of oxygen and hydrogen (569.). The volume of gases immediately
began to lessen, the diminution proceeding more and more rapidly until
about 3/4ths of the mixture had disappeared. The upper end of the tube
became quite warm, the plate itself so hot that the water boiled as it rose
over it; and in less than a minute a cubical inch and a half of the gases
were gone, having been combined by the power of the platina, and converted
into water.

571. This extraordinary influence acquired by the platina at the positive
pole of the pile, is exerted far more readily and effectively on oxygen and
hydrogen than on any other mixture of gases that I have tried. One volume
of nitrous gas was mixed with a volume of hydrogen, and introduced into a
tube with a plate which had been made positive in the dilute sulphuric acid
for four minutes (570.). There was no sensible action in an hour: being
left for thirty-six hours, there was a diminution of about one-eighth of
the whole volume. Action had taken place, but it had been very feeble.

572. A mixture of two volumes of nitrous oxide with one volume of hydrogen
was put with a plate similarly prepared into a tube (569. 570.). This also
showed no action immediately; but in thirty-six hours nearly a fourth of
the whole had disappeared, i.e. about half of a cubic inch. By comparison
with another tube containing the same mixture without a plate, it appeared
that a part of the diminution was due to solution, and the other part to
the power of the platina; but the action had been very slow and feeble.

573. A mixture of one volume olefiant gas and three volumes oxygen was not
affected by such a platina plate, even though left together for several
days (640. 641.).

574. A mixture of two volumes carbonic oxide and one volume oxygen was also
unaffected by the prepared platina plate in several days (645, &c.).

575. A mixture of equal volumes of chlorine and hydrogen was used in
several experiments, with plates prepared in a similar manner (570.).
Diminution of bulk soon took place; but when after thirty-six hours the
experiments were examined, it was found that nearly all the chlorine had
disappeared, having been absorbed, principally by the water, and that the
original volume of hydrogen remained unchanged. No combination of the
gases, therefore, had her