a liquid which we have just made up from copper and nitric acid, whilst
our other experiments were in hand; and though I am making this experiment
very hastily, and may bungle a little, yet I prefer to let you see what I
do rather than prepare it beforehand.

Now, see what happens. These two platinum-plates are the two ends (or I
will make them so immediately) of this apparatus; and I am about to put
them in contact with that solution just as we did a moment ago on the
paper. It does not matter to us whether the solution be on the paper or
whether it be in the jar, so long as we bring the ends of the apparatus to
it. If I put the two platinums in by themselves, they come out as clean
and as white as they go in [inserting them into the fluid without
connecting them with the battery]; but when we take the power and lay that
on [the platinums were connected with the battery and again dipped into
the solution], this, you see [exhibiting one of the platinums], is at once
turned into copper, as it were: it has become like a plate of copper; and
that [exhibiting the other piece of platinum] has come out quite clean. If
I take this coppered piece and change sides, the copper will leave the
right-hand side and come over to the left side; what was before the
coppered plate comes out clean, and the plate which was clean comes out
coated with copper; and thus you see that the same copper we put into this
solution we can also take out of it by means of this instrument.

Putting that solution aside, let us now see what effect this instrument
will have upon water. Here are two little platinum-plates which I intend
to make the ends of the battery, and this (C) is a little vessel so shaped
as to enable me to take it to pieces, and shew you its construction. In
these two cups (A and B) I pour mercury, which touches the ends of the
wires connected with the platinum-plates. In the vessel (C) I pour some
water containing a little acid (but which is put only for the purpose of