an as all attraction of particles may have this subtile agent
for their common cause. But as the effects investigated arose out of
electrical researches, as they are directly connected with other effects
which are of an electric nature, and must of necessity be understood and
guarded against in a very extensive series of electro-chemical
decompositions (707.), I have felt myself fully justified in describing
them in this place.

565. Believing that I had proved (by experiments hereafter to be described
(705.),) the constant and definite chemical action of a certain quantity of
electricity, whatever its intensity might be, or however the circumstances
of its transmission through either the body under decomposition or the more
perfect conductors were varied, I endeavoured upon that result to construct
a new measuring instrument, which from its use might be called, at least
provisionally, a _Volta-electrometer_ (739.)[A].

[A] Or Voltameter.--_Dec. 1838._

566. During the course of the experiments made to render the instrument
efficient, I was occasionally surprised at observing a deficiency of the
gases resulting from the decompositions of water, and at last an actual
disappearance of portions which had been evolved, collected, and measured.
The circumstances of the disappearance were these. A glass tube, about
twelve inches in length and 3/4ths of an inch in diameter, had two platina
poles fixed into its upper, hermetically sealed, extremity: the poles,
where they passed through the glass, were of wire; but terminated below in
plates, which were soldered to the wires with gold (Plate V. fig. 56.). The
tube was filled with dilute sulphuric acid, and inverted in a cup of the
same fluid; a voltaic battery was connected with the two wires, and
sufficient oxygen and hydrogen evolved to occupy 4/5ths of the tube, or by
the graduation, 116 parts. On separating the tube from the voltaic battery
the volume of gas immediately began to diminish, and in about five hours
only 13-1/2 parts remained, and these ultimately disappeared.

567. It was found by various experiments, that this effect was not due to
the escape or solution of the gas, nor to recombination of the oxygen or
hydrogen in consequence of any peculiar condition _they_ might be supposed
to possess under the circumstances; but to be occasioned by the action of
one or both of the poles within the tube upon the gas around them. On
disuniting the poles from the pile aft