of a
taper put into it, but having other properties.

Let me take a little quick-lime and pour some common water on to it--the
commonest water will do. I will stir it a moment, then pour it upon a
piece of filtering paper in a funnel, and we shall very quickly have a
clear water proceeding to the bottle below, as I have here. I have plenty
of this water in another bottle; but, nevertheless, I should like to use
the lime-water that was prepared before you, so that you may see what its
uses are. If I take some of this beautiful clear lime-water, and pour it
into this jar, which has collected the air from the candle, you will see a
change coming about. Do you see that the water has become quite milky?
Observe, that will not happen with air merely. Here is a bottle filled
with air; and if I put a little lime-water into it, neither the oxygen nor
the nitrogen, nor anything else that is in that quantity of air, will make
any change in the lime-water. It remains perfectly clear, and no shaking
of that quantity of lime-water with that quantity of air in its common
state will cause any change; but if I take this bottle with the
lime-water, and hold it so as to get the general products of the candle in
contact with it, in a very short time we shall have it milky. There is the
chalk, consisting of the lime which we used in making the lime-water,
combined with something that came from the candle--that other product
which we are in search of, and which I want to tell you about to-day. This
is a substance made visible to us by its action, which is not the action
of the lime-water either upon the oxygen or upon the nitrogen, nor upon
the water itself, but it is something new to us from the candle. And then
we find this white powder, produced by the lime-water and the vapour from
the candle, appears to us very much like whitening or chalk, and, when
examined, it does prove to be exactly the same substance as whitening or
chalk. So we are led, or have been led, to observe upon the various
circumstances of this experiment, and to trace this production of chalk to
its various causes, to give us the true knowledge of the nature of this
combustion of the candle--to find that this substance, issuing from the
candle, is exactly the same as that substance which would issue from a
retort, if I were to put some chalk into it with a little moisture, and
make it red-hot: you would then find that exactly the same substance would
issue from it as fr