The explanation of the draught is found in the well-known fact that hot air rises. When a fire is well under way a considerable current of heated air rises through the stovepipe and chim ney, which creates a strong draught. This, if not regulated, makes the fire roar and send up sparks that may set fire to the chimney or even to the roof. A feeble flame like that of a match creates very little suction. Hence to start a draught is one of the prob lems of fire building.
To Clean the Fire Box.—The first step in building a good coal or wood fire is to dump the grate, clean out the fire box, and remove the ashes from the ash pit beneath. The grate should be thoroughly freed from clink ers. The object of cleaning the grate and fire box is both to remove ashes that would take up heat at the ex pense of the kindling, and to admit the oxygen of the air through every part of the grate so as to kindle the fire uniformly and to penetrate every part of the fire box. No time is gained in attempting to kindle a stove or fur nace fire on top of old coal or ashes. The fire will kindle slowly if at all, will burn unevenly, and will be likely to go out during the day.
Chicken, turkey, and goose wings will be found useful to brush out the fire box of a range, hearth, or cook stove.
The object of cleaning out the ash pit is to create directly below the flame an empty air chamber in which the air will be warmed by radiation downward before it is drawn up into the fire.
To Lay Fires.—If the fire in a cook stove or range is allowed to go out at night, it is advisable to lay a fresh one in readiness for kindling next morning. Whatever kindling matter is employed should first be laid on the clean grate over the whole surface of the fire box. The substances used for kindling are usually of two sorts, one lighter and more inflammable than the other, as paper, excelsior, kero sene, or the like for the first, and kindling wood, charcoal, or coke for the second. Whatever kindling matter is employed, the most inflammable should be first laid over the whole surface of the grate, and in such quan tity as to certainly kindle the second. The second layer in like manner should cover the whole grate and in such quantity as to certainly kindle the fuel. And sufficient fuel should be laid on the top, or added at the proper time after ignition, to maintain the fire and to kindle additional fuel, thus forming a bed of coals across the en tire fire box.
The mistakes usually made in fire building are to use too little kindling, to lay kindling over a part of the grate instead of covering it; to use too much kindling and dispose it in such a way as to choke the draught, or to smother the kindling by covering it with such a large amount of cold, heavy fuel as to choke the draught and lower the temperature below the kindling point.
Hence a small amount of kindling spread uniformly over the fire box and lightly sprinkled with a small amount of coal or fed with a few small sticks of wood in the beginning will kindle a fire more quickly and surely than a much larger amount so disposed as to choke the draught and immediately smother it. Hence also such kindling as excelsior, which is finely cut and at the same time springy and elastic, by admitting the air to every part, heating quickly, and throw ing off a large quantity of inflammable gases, is better than leaves of books or newspapers, which tend to mat down and prevent the draught from coming through. Coke and charcoal are good kindling because they are porous, friable, and burn evenly for a long time.
To Lay a Furnace Fire.—Lay first sufficient paper or excelsior across the fire box to kindle the wood; on this lay a light wood kindling split fine and built corncob fashion clear across the fire box, placing the sticks closely enough to prevent the coal from fall ing through, but not to prevent the draught from coming up. A little coke or charcoal or a layer of hard wood across the fire box will serve to create a bed of coals to ignite the heavier fuel. But do not use more wood than is necessary; less will be required where the coal is not too coarse. Stove coal is large enough for most furnaces, and the smallest coal that the grate will admit will be found to give the best results.
After lighting the kindlings throw on j ust sufficient coal to make a single layer sprinkled evenly across the fire box. Keep the draught open until this is flaming brightly and cover with a thicker layer, also sprinkled evenly. When this burns up the fire box may be filled as needed.