will have practically no draft.

A soot pocket provided with a door for cleaning it out is very convenient. The door should be placed just below the smoke pipe opening, and care must be taken to see that it fits snugly and is always closed so tight that no air can get in.

SUPPORTING THE CHIMNEY.

All chimneys should be built from the ground up. None of the weight should be carried by any part of the building except the foundation. Proper foundations should be provided at least 12 inches wider all round than the chimney. If the chimney is an exterior one, and there is no basement or cellar, its foundation should be started well below the frost line. Otherwise the base of the chimney should be at the same level as the bottom of the foundation of the building.

No chimney should rest upon or be carried by wooden floors, beams, or brackets, nor should it be hung from wooden rafters. Wood construction shrinks, and beams supporting heavy loads always deflect in time. Sagging of the beams injures the walls and ceilings of the house and is apt to crack the chimney and render it dangerous. Chimneys usually extend several feet above the roof, exposing considerable surface to the wind, and unless the support is stable they are likely to sway during a gale with the possibility of the joints at the roof-line opening. Openings in a flue at this point are especially dangerous, for sparks from the flue may come into contact with the woodwork of the roof. This swaying may also cause leaks in the roof.

Fig. 7.—Chimney and roof connection. Sheet metal A should have shingles K over it at least 4 inches. Apron B bent as at E with base flashings C, D, and H and cap flashings P and G, lapping over the base flashings provide watertight construction. When the chimney contains two flues the joints should be separated as shown.

The brickwork around all fireplaces and flues should be laid with cement mortar, as it is more resistant than lime mortar to the action of heat and flue gases. It is well to use cement mortar for the entire chimney construction. All mortar used for chimney construction, except for laying firebrick, should be proportioned as follows: Two bags of Portland cement, not less than 188 pounds, and one bag of dry hydrated lime, 50 pounds, thoroughly mixed dry, and to this mixture should be added three times its volume of clean sand with sufficient water to produce proper consistency. When dry hydrated lime is not available, 1 cubic foot of completely slaked lime putty may be substituted for the dry hydrate.

CAPPING THE CHIMNEY.

Brick chimneys should be capped with stone, concrete, or cast-iron. Unless a chimney is capped the top courses of brick may become loosened and therefore dangerous. Plain topped chimneys will last longer and are safer than those of an ornamental character. The opening in the cap piece should be the full size of the flue.

CHIMNEY AND ROOF CONNECTION.

Where the chimney passes through the roof the construction should provide space for expansion due to temperature changes, settlement, or slight movement of the chimney during heavy winds. (See fig. 7.) Copper is the best material for flashings. It is easier to handle than galvanized sheet-metal, which is more often used because of its lesser cost, but which will corrode in time, both from inside and outside exposure. Tin or black iron are cheaper but will rust quickly unless frequently painted. Lead and zinc are expensive and should not be used for chimney flashings, for in case of fire under the roof they will melt and leave an opening to create a draft by which the intensity of the fire will be increased.

Fig. 8.—A. Wrong connection, producing interference and a poor draft. B. Correct construction, producing a good draft by providing a free passage for the gases.

CHIMNEY CONNECTIONS.

Proper care in setting and looking after smoke pipes connecting with chimneys would greatly lessen the number of fires chargeable to defective construction.

In fitting the smoke pipe no opening should be left around it, and the pipe should not project into the flue lining. (See fig. 8.) The joint should be made air-tight by a closely fitting collar and boiler putty or fireproof cement. The proper construction is shown in figure 8-B, but if the pipe extends into the flue a shelf is formed on which soot will accumulate, the flue area will be reduced and a poor draft may result.

Smoke pipes should enter the chimney horizontally, and the connection through the chimney wall to the flue should be made with fire clay or metal thimbles securely and tightly set in the masonry. If the walls are furred, no wood should be within 12 inches of thimbles or any part of the smoke pipe. The space between the thimble and wood furring should be covered with metal lath and plaster.

Fig. 9.—Smoke pipe passing through a partition. A, 7/8-inch sides of partition; B, 2 by 4 studs in partition; C, ventilating holes in the double galvanized iron ventilating thimble D. Thimble should be at least 12 inches larger than pipe S.

Flue holes when not in use should be closed with tight fitting metal covers. If the room is papered the metal covers may also be papered, provided there is no other smoke connection with the flue, or provided a protective coating of asbestos paper is first applied over the metal. If there is another connection the metal may become hot enough to scorch the unprotected wall paper or set it afire. No smoke pipe should be permitted within 18 inches of any woodwork unless at least that half of the pipe nearest the woodwork is protected properly by 1 inch or more of fireproof covering. A metal casing 2 inches from the upper half of the pipe is sometimes employed to protect woodwork directly above it. When a smoke pipe is so protected it should never be less than 9 inches from any woodwork or combustible material. The storage of wooden boxes, barrels, or any combustible should not be permitted under or near a furnace smoke Pipe.

If a smoke pipe must be carried through a wood partition the woodwork should be properly protected. This can be done by cutting an opening in the partition and inserting a galvanized iron double-walled ventilating thimble at least 12 inches larger than the smoke pipe (see fig. 9), or protection may be afforded by at least 4 inches of brickwork or other incombustible material. Smoke pipes should not pass through floors, closets, or