style="font-size:15px;"> Q. What is smoke?
A. Small particles of carbon, separated by combustion from the fuel, but not consumed.
Q. Why do smoke and steam curl, as they ascend?
A. Because they are moved in a right line, and then pushed on all sides; and this forces them into a circular motion.
Q. What are blacks?
A. When the hot air of the chimney has been cooled by the external air, it can no longer buoy up the solid smoke; so it falls to the earth in condensed flakes, called “blacks.”
Q. Why are there no blacks in the smoke of a railway engine?
A. The smoke of a railway engine consists chiefly of watery vapour, which dissolves in air, as sugar does in water; but the smoke of a common chimney consists of small fragments of unburnt fuel.
Q. Why does a “COPPER HOLE” DRAW up more fiercely than an open stove?
A. As the air, which supplies the copper hole, must pass through the furnace, it becomes exceedingly heated, and rushes up the chimney with great violence.
Q. What produces the roaring noise made by a copper-hole fire?
A. Air rushing rapidly through the crevices of the iron door, and up the chimney flue.
Q. Why is the roar less, if the copper-hole door be thrown open?
A. Because fresh air gets access to the fire more easily; and as the air is not so intensely heated, its motion is not so violent.
Q. Why do some chimneys smoke?
A. If fresh air is not admitted into a room, as fast as it is consumed by the fire, a current of air will rush down the chimney to supply the deficiency, and bring the smoke along with it.
Q. What prevents air being supplied, as fast as it is consumed by the fire?
A. Leather and curtains round the doors; sand-bags at the threshhold and on the window-frames; and other contrivances to keep out the draught.
Q. Why is it needful for cold fresh air to be so constantly supplied?
A. If water be taken with a pail out of a river, other water will rush towards the hole, as soon as the pail is lifted out; and if air be taken from a room, (as it is, when some of it goes up the chimney) other air will rush towards the void to fill it up.
Q. Why will it come down the chimney?
A. Because if doors and windows are all made air-tight, it can get to the room in no other way.
Q. What is the best remedy in such a case?
A. The speediest remedy is to open the door or window: but by far the best remedy is to carry a small tube from the hearth into the external air.
Q. Why is that the best remedy?
A. Because the fire will be plentifully supplied with air by the tube; the doors and windows may all remain air-tight; and we may enjoy a warm fireside, without the inconvenience of draughts and cold feet.
Q. Why is a chimney raised so high above the roof?
A. If it were not so, it would smoke; as all funnels do which are too short.
Q. What is meant by the funnel, or flue of a chimney?
A. That part of a chimney through which the smoke passes, is called the funnel, or flue.
Q. Why does a chimney smoke, if the funnel be very short?
A. Because the draught of a short flue is too slack to carry the smoke up the chimney.
Q. Why is the draught of a short flue more slack that that of a long one?
A. For many reasons. 1st—The fire is always dull and sluggish if the chimney be too short.
2ndly—The smoke rolls out of the chimney, before it has acquired its full velocity.
3rdly—The wind, rain, and air, have more influence over a short funnel, than over a long one.
Q. Why is the fire always dull and sluggish if the chimney-flue be very short?
A. Because the draught is so bad: and as the rarefied air passes up the chimney very tardily, fresh air flows as tardily towards the fire, to supply it with oxygen.
Q. On what does the intensity of fire depend?
A. The intensity of fire is always in proportion to the quantity of oxygen with which it is supplied.
Q. Why does not smoke acquire its full velocity in a short funnel?
A. Because the higher smoke ascends in a flue, (provided it be clear and hot) the faster it goes; (as a stone falls faster and faster the lower it descends): if, therefore, a funnel be very short, the smoke never acquires its full velocity.
Q. Does the draught of a chimney depend on the speed of the smoke through the flue?
A. Yes. The more quickly hot air flies up the chimney, the more quickly cold air will rush towards the fire to supply the place; and, therefore, the longer the flue, the greater the draught.
Q. Why is the draught of a long flue greater than that of a short one?
A. Because the higher smoke ascends, the faster it goes; (as a stone falls faster and faster, the nearer it approaches to the earth): if, therefore, a funnel be long, the smoke acquires great velocity, and the draught is great.
Q. If a chimney be too short, and cannot be lengthened, what is the best remedy to prevent smoking?
A. To contract the opening of the chimney contiguous to the stove.
Q. Why will a smaller opening against the stove prevent the smoking?
A. As all the air (which enters the chimney) must pass near the fire, it will become greatly heated, and rise rapidly through the funnel; and this increase of heat will compensate for the shortness of the flue.
Q. Why will a room smoke,
