Certainly.—The apparatus which you see here ([Plate XI.] fig. 3.), may be used to exemplify what we have just said. It consists in a kind of open furnace, through which a porcelain tube, containing charcoal, passes. To one end of the tube is adapted a glass retort with water in it; and the other end communicates with a receiver placed on the water-bath. A lamp being applied to the retort, and the water made to boil, the vapour is gradually conveyed through the red-hot charcoal, by which it is decomposed; and the hydrogen gas which results from this decomposition is collected in the receiver. But the hydrogen thus obtained is far from being pure; it retains in solution a minute portion of carbon, and contains also a quantity of carbonic acid. This renders it heavier than pure hydrogen gas, and gives it some peculiar properties; it is distinguished by the name of carbonated hydrogen gas.
CAROLINE.
And whence does it obtain the carbonic acid that is mixed with it?
EMILY.
I believe I can answer that question, Caroline.—From the union of the oxygen (proceeding from the decomposed water) with the carbon, which, you know, makes carbonic acid.
CAROLINE.
True; I should have recollected that.—The product of the decomposition of water by red-hot charcoal, therefore, is carbonated hydrogen gas, and carbonic acid gas.
MRS. B.
You are perfectly right now.
Carbon is frequently found combined with hydrogen in a state of solidity, especially in coals, which owe their combustible nature to these two principles.