The Chemical History of a Candle | Page 8

flames so that they will look like fixtures, and we can
photograph them--indeed, we have to photograph them--so that they

become fixed to us, if we wish to find out everything concerning them.
That, however, is not the only thing I wish to mention. If I take a flame
sufficiently large, it does not keep that homogeneous, that uniform
condition of shape, but it breaks out with a power of life which is quite
wonderful. I am about to use another kind of fuel, but one which is
truly and fairly a representative of the wax or tallow of a candle. I have
here a large ball of cotton, which will serve as a wick. And, now that I
have immersed it in spirit and applied a light to it, in what way does it
differ from an ordinary candle? Why, it differs very much in one
respect, that we have a vivacity and power about it, a beauty and a life
entirely different from the light presented by a candle. You see those
fine tongues of flame rising up. You have the same general disposition
of the mass of the flame from below upwards; but, in addition to that,
you have this remarkable breaking out into tongues which you do not
perceive in the case of a candle. Now, why is this? I must explain it to
you, because when you understand that perfectly, you will be able to
follow me better in what I have to say hereafter. I suppose some here
will have made for themselves the experiment I am going to shew you.
Am I right in supposing that anybody here has played at snapdragon? I
do not know a more beautiful illustration of the philosophy of flame, as
to a certain part of its history, than the game of snapdragon. First, here
is the dish; and let me say, that when you play snapdragon properly,
you ought to have the dish well-warmed; you ought also to have warm
plums and warm brandy, which, however, I have not got. When you
have put the spirit into the dish, you have the cup and the fuel; and are
not the raisins acting like the wicks? I now throw the plums into the
dish, and light the spirit, and you see those beautiful tongues of flame
that I refer to. You have the air creeping in over the edge of the dish
forming these tongues. Why? Because, through the force of the current
and the irregularity of the action of the flame, it cannot flow in one
uniform stream. The air flows in so irregularly that you have what
would otherwise be a single image, broken up into a variety of forms,
and each of these little tongues has an independent existence of its own.
Indeed, I might say, you have here a multitude of independent candles.
You must not imagine, because you see these tongues all at once, that
the flame is of this particular shape. A flame of that shape is never so at
any one time. Never is a body of flame, like that which you just saw

rising from the ball, of the shape it appears to you. It consists of a
multitude of different shapes, succeeding each other so fast that the eye
is only able to take cognisance of them all at once. In former times, I
purposely analysed a flame of that general character, and the diagram
shews you the different parts of which it is composed. They do not
occur all at once: it is only because we see these shapes in such rapid
succession, that they seem to us to exist all at one time.
[Illustration: Fig. 6.]
It is too bad that we have not got further than my game of snapdragon;
but we must not, under any circumstances, keep you beyond your time.
It will be a lesson to me in future to hold you more strictly to the
philosophy of the thing, than to take up your time so much with these
illustrations.

LECTURE II.
A CANDLE: BRIGHTNESS OF THE FLAME--AIR NECESSARY
FOR COMBUSTION--PRODUCTION OF WATER.
We were occupied the last time we met in considering the general
character and arrangement as regards the fluid portion of a candle, and
the way in which that fluid got into the place of combustion. You see,
when we have a candle burning fairly in a regular, steady atmosphere,
it will have a shape something like the one shewn in the diagram, and
will look pretty uniform, although very curious in its character. And
now, I have to ask your attention to the means by which we are enabled
to ascertain what happens in any particular part of the flame--why it
happens, what it does in happening, and where, after