if it were burnt as part of a
candle. The heat that is in the flame of a candle decomposes the vapour
of the wax, and sets free the carbon particles--they rise up heated and
glowing as this now glows, and then enter into the air. But the
particles when burnt never pass off from a candle in the form of carbon.
They go off into the air as a perfectly invisible substance, about which
we shall know hereafter.

Is it not beautiful to think that such a process is going on, and that
such a dirty thing as charcoal can become so incandescent? You see, it
comes to this--that all bright flames contain these solid particles; all
things that burn and produce solid particles, either during the time
they are burning, as in the candle, or immediately after being burnt, as
in the case of the gunpowder and iron-filings--all these things give us
this glorious and beautiful light.

_III.--The Products of Combustion_

We observe that there are certain products as the result of the
combustion of a candle, and that of these products one portion may be
considered as charcoal, or soot; that charcoal, when afterwards burnt,
produces some other product--carbonic acid, as we shall see; and it
concerns us very much now to ascertain what yet a third product is.

Suppose I take a candle and place it under a jar. You see that the sides
of the jar become cloudy, and the light begins to burn feebly. It is the
products, you see, which make the light so dim, and this is the same
thing which makes the sides of the jar so opaque. If you go home and
take a spoon that has been in the cold air, and hold it over a
candle--not so as to soot it--you will find that it becomes dim, just as
that jar is dim. If you can get a silver dish, or something of that
kind, you will make the experiment still better. It is _water_ which
causes the dimness, and we can make it, without difficulty, assume the
form of a liquid.

And so we can go on with almost all combustible substances, and we 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 a ladle, or
anything else may be used, provided it be clean, and can carry off the
heat, and so condense the water.

And now--to go into the history of this wonderful production of water
from combustibles, an