FIRING WITH COAL.
After fire is well started with wood, throw coal into the center of grate, and do not disturb it until it is well ignited and burning briskly; then break the fire down and put in a shovel or two of coal, and so continue keeping the grates covered with a thin layer.
Always aim to put in fresh coal on a rising head of steam pressure. Never pile coal against the flue sheet or keep the fire box too full. Nothing is gained by the latter, but much is lost.
Q. Which is the more economical to burn, wet or dry coal?
A. Dry. If your coal is wet, you simply have to evaporate that much more water, which goes out of the stack instead of to the engine.
Q. How much water will one pound of coal evaporate?
A. One pound of coal will, under very favorable circumstances, evaporate twelve pounds of water, but the average evaporative power of anthracite coal is 9½ pounds of water, and semi-bituminous coal is 9⁹/₁₀ pounds.
Q. If cold air is allowed to strike the flue sheet and flues, what is the result?
A. It will eventually cause them to leak.
Q. How should a fire be regulated in case of temporary stoppage by accident or otherwise under full head of steam?
A. Close the damper and keep the fire door closed; then open small door in smoke box or the damper in chimney.
Q. Why not leave the fire door open?
A. Because it would allow the cold air to come in contact with flue sheet and flues, and consequent damage to boiler.