A. 20 pounds.
Q. How much wood equals one ton of soft coal for steam purposes?
A. About 4,000 pounds of wood.
Q. How long have you run engines?
Q. Have you ever done your own firing?
Q. What is the source of all power in the steam engine?
A. The heat stored up in the coal.
Q. How is the heat liberated from the coal?
A. By burning it; that is, by combustion.
Q. Of what does coal consist?