The Chemical History of a Candle | Page 4

set
them at work in the performance of their proper functions. You observe
a candle is a very different thing from a lamp. With a lamp you take a
little oil, fill your vessel, put in a little moss or some cotton prepared by
artificial means, and then light the top of the wick. When the flame
runs down the cotton to the oil, it gets extinguished, but it goes on
burning in the part above. Now, I have no doubt you will ask, how is it

that the oil, which will not burn of itself, gets up to the top of the cotton,
where it will burn? We shall presently examine that; but there is a
much more wonderful thing about the burning of a candle than this.
You have here a solid substance with no vessel to contain it; and how is
it that this solid substance can get up to the place where the flame is?
How is it that this solid gets there, it not being a fluid? or, when it is
made a fluid, then how is it that it keeps together? This is a wonderful
thing about a candle.
We have here a good deal of wind, which will help us in some of our
illustrations, but tease us in others; for the sake, therefore, of a little
regularity, and to simplify the matter, I shall make a quiet flame--for
who can study a subject when there are difficulties in the way not
belonging to it? Here is a clever invention of some costermonger or
street stander in the market-place for the shading of their candles on
Saturday nights, when they are selling their greens, or potatoes, or fish.
I have very often admired it. They put a lamp-glass round the candle,
supported on a kind of gallery, which clasps it, and it can be slipped up
and down as required. By the use of this lamp-glass, employed in the
same way, you have a steady flame, which you can look at, and
carefully examine, as I hope you will do, at home.
You see, then, in the first instance, that a beautiful cup is formed. As
the air comes to the candle it moves upwards by the force of the current
which the heat of the candle produces, and it so cools all the sides of
the wax, tallow, or fuel, as to keep the edge much cooler than the part
within; the part within melts by the flame that runs down the wick as
far as it can go before it is extinguished, but the part on the outside does
not melt. If I made a current in one direction, my cup would be
lop-sided, and the fluid would consequently run over,--for the same
force of gravity which holds worlds together holds this fluid in a
horizontal position, and if the cup be not horizontal, of course the fluid
will run away in guttering. You see, therefore, that the cup is formed by
this beautifully regular ascending current of air playing upon all sides,
which keeps the exterior of the candle cool. No fuel would serve for a
candle which has not the property of giving this cup, except such fuel
as the Irish bogwood, where the material itself is like a sponge, and

holds its own fuel. You see now why you would have had such a bad
result if you were to burn these beautiful candles that I have shewn you,
which are irregular, intermittent in their shape, and cannot therefore
have that nicely-formed edge to the cup which is the great beauty in a
candle. I hope you will now see that the perfection of a process--that is,
its utility--is the better point of beauty about it. It is not the best looking
thing, but the best acting thing, which is the most advantageous to us.
This good-looking candle is a bad burning one. There will be a
guttering round about it because of the irregularity of the stream of air
and the badness of the cup which is formed thereby. You may see some
pretty examples (and I trust you will notice these instances) of the
action of the ascending current when you have A little gutter run down
the side of a candle, making it thicker there than it is elsewhere. As the
candle goes on burning, that keeps its place and forms a little pillar
sticking up by the side, because, as it rises higher above the rest of the
wax or fuel, the air gets better round it, and it is more cooled and better
able to resist the action of the heat at a little distance. Now, the greatest
mistakes and faults with regard to candles, as in many other things,
often bring with them instruction