I will shew you that potassium has the same action upon it as upon the
water in that basin in the experiment we have just tried. See, it takes
fire, and burns in just the same manner. I will take another drop upon
this glass slab, and when I put the potassium on to it, you see at once,
from its taking fire, that there is water present. Now, that water was
produced by the candle. In the same manner, if I put this spirit-lamp
under that jar, you will soon see the latter become damp, from the dew
which is deposited upon it--that dew being the result of combustion; and I
have no doubt you will shortly see by the drops of water which fall upon
the paper below, that there is a good deal of water produced from the
combustion of the lamp. I will let it remain, and you can afterwards see
how much water has been collected. So, if I take a gas-lamp, and put any
cooling arrangement over it, I shall get water--water being likewise
produced from the combustion of gas. Here, in this bottle, is a quantity
of water--perfectly pure, distilled water, produced from the combustion of
a gas-lamp--in no point different from the water that you distil from the
river, or ocean, or spring, but exactly the same thing. Water is one
individual thing--it never changes. We can add to it by careful
adjustment, for a little while, or we can take it apart, and get other
things from it; but water, as water, remains always the same, either in a
solid, liquid, or fluid state. Here, again [holding another bottle], is
some water produced by the combustion of an oil-lamp. A pint of oil, when
burnt fairly and properly, produces rather more than a pint of water.
Here, again, is some water, produced by a rather long experiment from a
wax candle. And so we can go on with almost all combustible substances,
and find that if they burn with a flame, as a candle, they produce water.
You may make these experiments yourselves. The head of a poker is a very
good thing to try with, and if it remains cold long enough over the
candle, you may get water condensed in drops on it; or a spoon or ladle,
or anything else may be used, provided it be clean, and can carry off the