A. As the air of the room passes over the fire, it becomes heated; and (being thus made lighter,) ascends the chimney, carrying the smoke with it.

A. Small particles of carbon, separated by combustion from the fuel, but not consumed.

A. Because they are moved in a right line, and then pushed on all sides; and this forces them into a circular motion.

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.”

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.

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.

A. Air rushing rapidly through the crevices of the iron door, and up the chimney flue.

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.

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.

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.

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.

A. Because if doors and windows are all made air-tight, it can get to the room in no other way.

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.

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.

A. If it were not so, it would smoke; as all funnels do which are too short.

A. That part of a chimney through which the smoke passes, is called the funnel, or flue.

A. Because the draught of a short flue is too slack to carry the smoke up the chimney.

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.

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.

A. The intensity of fire is always in proportion to the quantity of oxygen with which it is supplied.

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.

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.

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.

A. To contract the opening of the chimney contiguous to the stove.

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.

A. Because the fiercer fire will exhaust the most air; and draw from the smaller one, to supply its demand.

A. Whenever the door between the two rooms is opened, air will rush from the chimney of the inferior fire, to supply the other; and both rooms will be filled with smoke.

A. Let a tube be carried from the hearth of each stove, into the external air; and then each fire will be so well supplied, that neither will need to borrow from the other.

A. Because the wind (striking against the steeple) is reflected back; and tumbles down the vestry chimney, forcing the smoke into the room.

A. Those from the north-east or south-east; according to the position of the vestry.

A. Because they strike against the steeple, and bound back to the vestry chimney: but western winds cannot rebound over the roof of a church.

(N. B. The steeple of a church is always due west, and the other end of the church due east; if, therefore, a western wind rebound, it would rebound to the west, or away from the church, and not towards it.)

A. Because the wind (striking against the surrounding hills) rebounds back again upon the chimney, and destroys its draught.

A. To fix a cowl on the chimney top, to turn like a weather-cock, and present its back to the wind.

A. If the wind be strong, it will keep the opening of the cowl towards the steeple or hill; and then the reflected wind will blow into the cowl, and down the chimney.

A. If the chimney flue can be carried higher than the steeple or hills, no wind can enter the flue.

A. Because the reflected wind would strike against the sides of the chimney-flue, and not pass over the opening at all.

A. If both door and chimney be placed on the same side of a room, the chimney will often smoke.

A. Because when the door is opened, a current of air will blow into the chimney-place, and drive the smoke into the room.

A. The door must be set opposite to the chimney, or nearly so; and then the draught from the door will blow the smoke up the chimney, and not into the room.

A. Because the obstruction in the chimney (presented by the loose soot, to the free passage of the smoke) delays its current, and prevents the draught.

A. 1st—Because the loose mortar and bricks obstruct the smoke: and

2ndly—The cold air (oozing through the chinks) chills the air in the chimney, and prevents its ascent.

A. Because the cold air (which gets through the joints) chills the air in the flue, and prevents its ascent.

A. Because the opening is so very large, that much of the air which goes up the chimney, has never passed near the fire; and this cold air mixing with the other, so reduces its temperature, that it ascends very slowly, and the draught is destroyed.

A. Because, unless the current of air up the chimney be very powerful, it cannot buoy the smoke up through the flue.

A. The chimney-place must be contracted.

A. As the air will then pass nearer the fire, it will be more heated, and fly up the chimney much faster.

A. The gust (blowing the air away from the top of the chimney) removes (for a time) all resistance to the smoke: but when the wind lulls again, the resistance of the air suddenly returns—the draught is checked—and a puff of smoke rushes into the room.

A. When the opening of a chimney is large, the top must be contracted by a chimney-pot, in order to increase the draught.

A. As the same quantity of hot air has to escape through a much smaller opening, it must pass through more quickly.

A. Because they compel the air to go through the fire, and not over it; therefore the fire is well supplied with oxygen, and the draught greatly increased.

A. As all the air which enters the chimney has to pass through the fire, it is much hotter, and ascends the chimney very fast; and the faster the air flies up the chimney, the faster it rushes towards the fire also.

A. The air in the chimney (being colder than the air in the parlour) descends into the room, and leaves a disagreeable smell of soot behind.