.

[Illustration: Fig. 12.]

And what do you think the bulk of that water is when it assumes the
vaporous condition? You see that cube [pointing to a cubic foot]. There,
by its side, is a cubic inch, exactly the same shape as the cubic foot,
and that bulk of water [the cubic inch] is sufficient to expand into that
bulk [the cubic foot] of steam; and, on the contrary, the application of
cold will contract that large quantity of steam into this small quantity
of water.

[Illustration: Fig. 13.]

[One of the iron bottles burst at that moment.] Ah! There is one of our
bottles burst, and here you see is a crack down one side an eighth of an
inch in width. [The other now exploded, sending the freezing mixture in
all directions.] This other bottle is also broken; although the iron was
nearly half-an-inch thick, the ice has burst it asunder. These changes
always take place in water: they do not require to be always produced by
artificial means,--we only use them here because we want to produce a
small winter round that little bottle, instead of a long and severe one.
But if you go to Canada, or to the North, you will find the temperature
there out of doors will do the same thing as has been done here by the
freezing mixture.

To return to our quiet philosophy. We shall not in future be deceived,
therefore, by any changes that are produced in water. Water is the same
everywhere, whether produced from the ocean or from the flame of the
candle. Where, then, is this water which we get from a candle? I must
anticipate a little, and tell you. It evidently comes, as to part of it,
from the candle; but is it within the candle beforehand? No. It is not in
the candle; and it is not in the air round about the candle which is
necessary for its combustion. It is neither in one nor the other, but it
comes from their conjoint action, a part from the candle, a part from the
air; and this we have now to trace, so that we may understand thoroughly
what is the chemical history of a candle when we have it burning on our
table. How shall we get at this? I myself know plenty of ways, but I want
_you_ to get at it from the association in your own minds of what I have
already told you.

I think you can see a little in this way. We had just now the case of a
substance which acted upon the water in the way that Sir Humphrey Davy
shewed us[13], and which I am now going to recall to your minds by making
again an experiment upon that dish. It is a t