Indeed, you have yourselves frequently tried a very pretty
experiment, by which you may see the carbon in wood. If you take a piece
of wood, and partly burn it, and then blow it out, you have carbon left.
There are things that do not shew carbon in this way. A candle does not
shew it, but it contains carbon. Here also is a jar of coal-gas, which
produces carbonic acid abundantly. You do not see the carbon, but we can
soon shew it to you. I will light it, and as long as there is any gas in
this cylinder it will go on burning. You see no carbon, but you see a
flame; and because that is bright, it will lead you to guess that there is
carbon in the flame. But I will shew it to you by another process. I have
some of the same gas in another vessel, mixed with a body that will burn
the hydrogen of the gas, but will not burn the carbon. I will light them
with a burning taper, and you perceive the hydrogen is consumed, but not
the carbon, which is left behind as a dense black smoke. I hope that by
these three or four experiments you will learn to see when carbon is
present, and understand what are the products of combustion, when gas or
other bodies are thoroughly burned in the air.
Before we leave the subject of carbon, let us make a few experiments and
remarks upon its wonderful condition as respects ordinary combustion.
Pages:
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131