Making Coal Gas
Here is a very simple way of obtaining coal gas.
Procure an ordinary long clay tobacco pipe, the bowl of which should be filled with very small pieces of coal. Carefully cover the top with soft clay, and put the bowl in the fire, with the long stem protruding through the bars. Now watch this end of the pipe very closely and see what happens.
Fig. 14.—Simple gas-making.
Very soon you will notice a light-colored smoke issuing from the mouthpiece, but after a time this smoke disappears. But what happens if you hold a lighted match to the mouthpiece of the pipe? Immediately a bright yellow flame appears ([Fig. 14]).
The gas now burning is the same gas as is burnt in your house, although this latter, of course, is much purer.
If now you take the pipe from the fire, allow it to cool and then break it, you will be surprised to find that its contents have changed in appearance, for, in place of the coal, you will see what looks like a cinder. This is the coke. Thus you have manufactured gas from coal, at the same time producing coke.