you have seen
acting upon the water by the assistance of an acid, in such a manner as to
cause all the power to be evolved in the place where we require it I have
behind me a voltaic pile, and I am just about to shew you, at the end of
this lecture, its character and power, that you may see what we shall have
to deal with when next we meet. I hold here the extremities of the wires
which transport the power from behind me, and which I shall cause to act
on the water.

We have previously seen what a power of combustion is possessed by the
potassium, or the zinc, or the iron-filings; but none of them shew such
energy as this. [The Lecturer here made contact between the two terminal
wires of the battery, when a brilliant flash of light was produced.] This
light is, in fact, produced by a forty-zinc power of burning: it is a
power that I can carry about in my hands, through these wires, at
pleasure--although, if I applied it wrongly to myself, it would destroy me
in an instant, for it is a most intense thing, and the power you see here
put forth while you count five [bringing the poles in contact, and
exhibiting the electric light] is equivalent to the power of several
thunder-storms, so great is its force[14]. And that you may see what
intense energy it has, I will take the ends of the wires which convey the
power from the battery, and with it I dare say I can burn this iron file.
Now, this is a chemical power, and one which, when we next meet, I shall
apply to water, and shew you what results we are able to produce.

LECTURE IV.

HYDROGEN IN THE CANDLE--BURNS INTO WATER--THE OTHER PART OF WATER--OXYGEN.

I see you are not tired of the candle yet, or I am sure you would not be
interested in the subject in the way you are. When our candle was burning,
we found it produced water exactly like the water we have around us; and
by further examination of this water we found in it that curious body,
hydrogen--that light substance of which there is some in this jar. We
afterwards saw the burning powers of that hydrogen, and that it produced
water. And I think I introduced to your notice an apparatus which I very
briefly said was an arrangement of chemical force, or power, or energy, so
adjusted as to convey its power to us in these wires; and I said I should
use that force to pull the water to pieces, to see what else there was in
the water besides hydrogen; because, you remember, when we passed the
water through the iron t