hich it will be subjected.

The Chemical History of a Candle

"The Chemical History of a Candle" was the most famous course in
the long and remarkable series of Christmas lectures, "adapted to a
juvenile auditory," at the Royal Institution, and remains a
rarely-approached model of what such lectures should be. They were
illustrated by experiments and specimens, but did not depend upon
these for coherence and interest. They were delivered in 1860-61,
and have just been translated, though all but half-a-century old,
into German.

_I.--Candles and their Flames_

There is not a law under which any part of this universe is governed
that does not come into play in the phenomena of the chemical history of
a candle. There is no better door by which you can enter into the study
of natural philosophy than by considering the physical phenomena of a
candle.

And now, my boys and girls, I must first tell you of what candles are
made. Some are great curiosities. I have here some bits of timber,
branches of trees particularly famous for their burning. And here you
see a piece of that very curious substance taken out of some of the bogs
in Ireland, called _candle-wood_--a hard, strong, excellent wood,
evidently fitted for good work as a resister of force, and yet withal
burning so well that, where it is found, they make splinters of it, and
torches, since it burns like a candle, and gives a very good light
indeed. And in this wood we have one of the most beautiful illustrations
of the general nature of a candle that I can possibly give. The fuel
provided, the means of bringing that fuel to the place of chemical
action, the regular and gradual supply of air to that place of
action--heat and light all produced by a little piece of wood of this
kind, forming, in fact, a natural candle.

But we must speak of candles as they are in commerce. Here are a couple
of candles commonly called dips. They are made of lengths of cotton cut
off, hung up by a loop, dipped into melted tallow, taken out again and
cooled; then re-dipped until there is an accumulation of tallow round
the cotton. However, a candle, you know, is not now a greasy thing like
an ordinary tallow candle, but a clean thing; and you may almost scrape
off and pulverise the drops which fall from it without soiling anything.

The candle I have in my hand is a stearine candle, made of stearine from
tallow. Then here is a sperm can