I
introduce a flame into the gas, and you will see whether it will be put
out. You see the light is extinguished. Indeed, the gas may, perhaps, put
out phosphorus, which, you know, has a pretty strong combustion. Here is a
piece of phosphorus heated to a high degree. I introduce it into gas, and
you observe the light is put out; but it will take fire again in the air,
because there it re-enters into combustion. Now, let me take a piece of
potassium, a substance which, even at common temperatures, can act upon
carbonic acid, though not sufficiently for our present purpose, because it
soon gets covered with a protecting coat; but if we warm it up to the
burning point in air, as we have a fair right to do, and as we have done
with phosphorus, you will see that it can burn in carbonic acid; and if it
burns, it will burn by taking oxygen, so that you will see what is left
behind. I am going, then, to burn this potassium in the carbonic acid, as
a proof of the existence of oxygen in the carbonic acid. [In the
preliminary process of heating, the potassium exploded.] Sometimes we get
an awkward piece of potassium that explodes, or something like it, when it
burns. I will take another piece; and now that it is heated, I introduce
it into the jar, and you perceive that it burns in the carbonic acid--not
so well as in the air, because the carbonic acid contains the oxygen
combined; but it does burn, and takes away the oxygen.
Pages:
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129