hemselves
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