cause the steps of our demonstration to be so simple that you can never
for a moment lose the train of reasoning, if you only pay attention. All
the carbon which is burned in oxygen, or air, comes out as carbonic acid,
whilst those particles which are not so burned shew you the second
substance in the carbonic acid--namely, the carbon--that body which made
the flame so bright whilst there was plenty of air, but which was thrown
off in excess when there was not oxygen enough to burn it.

I have also to shew you a little more distinctly the history of carbon and
oxygen, in their union to make carbonic acid. You are now better able to
understand this than before, and I have prepared three or four experiments
by way of illustration. This jar is filled with oxygen, and here is some
carbon which has been placed in a crucible, for the purpose of being made
red-hot. I keep my jar dry, and venture to give you a result imperfect in
some degree, in order that I may make the experiment brighter. I am about
to put the oxygen and the carbon together. That this is carbon (common
charcoal pulverised), you will see by the way in which it burns in the air
[letting some of the red-hot charcoal fall out of the crucible]. I am now
about to burn it in oxygen gas, and look at the difference. It may appear
to you at a distance as if it were burning with a flame; but it is not so.
Every little piece of charcoal is burning as a spark, and whilst it so
burns it is producing carbonic acid. I specially want these two or three
experiments to point out what I shall dwell upon more distinctly
by-and-by--that carbon burns in this way, and not as a flame.

Instead of taking many particles of carbon to burn, I will take a rather
large piece, which will enable you to see the form and size; and to trace
the effects very decidedly. Here is the jar of oxygen, and here is the
piece of charcoal, to which I have fastened a little piece of wood, which
I can set fire to, and so commence the combustion, which I could not