atmosphere; there is a regular stream of it. I have provided means to
carry off the imperfectly burned part, lest it should annoy you. Look at
the soots that fly off from the flame: see what an imperfect combustion it
is, because it cannot get enough air. What, then, is happening? Why,
certain things which are necessary to the combustion of a candle are
absent, and very bad results are accordingly produced; but we see what
happens to a candle when it is burnt in a pure and proper state of air. At
the time when I shewed you this charring by the ring of flame on the one
side of the paper, I might have also shewn you, by turning to the other
side, that the burning of a candle produces the same kind of
soot charcoal or carbon.
But, before I shew that, let me explain to you as it is quite necessary
for our purpose that, though I take a candle and give you, as the general
result, its combustion in the form of a flame, we must see whether
combustion is always in this condition, or whether there are other
conditions of flame; and we shall soon discover that there are, and that
they are most important to us. I think, perhaps, the best illustration of
such a point to us, as juveniles, is to shew the result of strong
contrast. Here is a little gunpowder. You know that gunpowder burns with
flame we may fairly call it flame. It contains carbon and other
materials, which altogether cause it to burn with a flame. And here is
some pulverised iron, or iron filings. Now, I purpose burning these two
things together. I have a little mortar in which I will mix them. (Before
I go into these experiments, let me hope that none of you, by trying to
repeat them, for fun s sake, will do any harm. These things may all be
very properly used if you take care; but without that, much mischief will
be done.) Well, then, here is a little gunpowder, which I put at the
bottom of that little wooden vessel, and mix the iron filings up with it,
my object being to make the gunpowder set fire to the filings and burn
them in the air, and thereby shew the difference between substances
burning with flame and not with flame. Here is the mixture; and when I set
fire to it, you must watch the combustion, and you will see that it is of
two kinds. You will see the gunpowder burning with a flame, and the
filings thrown up. You will see them burning too, but without the
production of flame. They will each burn separately. [The Lecturer then
ignited the mixture.] There is the gunpowder, which burns with a flame;
and there are the filings they burn with a different kind of combustion.
You see, then, these two great distinctions; and upon these differences
depend all the utility and all the beauty of flame which we use for the
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