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 all, the whole candle goes to: because, as
you know very well, a candle being brought before us and burned,