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The amount of heat passing in an hour through a glass ceiling or roof will be given by the formula

C KS(T-T')
=

Engineers only admit for the co-efficient K the value K = 1, while the data obtained at Ferrières seem to show that for a double glass covering that is to say, a glass roof and a glass ceiling-it should have the value K = 3, and for a single covering K = 4, especially as in the latter case cold air might penetrate into the interior through the joints of the glass.

According to these values, allowing that the developed surface S' of the roof is one and a half times that of the glass ceiling S, the amount of coal to be burned in the coldest weather may be calculated as follows: Let

S = 1,000 square feet;

S' = 1,500 square feet;

The temperature of the external air be 140;

The temperature to be maintained within the roof be 1130;
The temperature of the room, 59°:

The amount of heat passing off through the glass roof will be—
C = 3 × 1500 (113 — 14) =

...

The amount of heat passing off through the glass ceiling will be

C = 3 x 1000 (113-59)=

The amount of heat to be developed within the double roof=

445, 500 units.

162,000 units.

... 607,500 units. Admitting that the coke-stoves employed utilize, as is almost always the case under similar circumstances, 90 per cent. of the heat given out by the fuel, and that a pound of coke produces 12,600 units of heat, it is necessary 607500 to burn every hour =53.57 pounds of coke an hour to prevent, .90 × 12600 under these almost extreme conditions of cold in Paris, the glass from cooling the room beyond 59°. At evening-receptions, the lighting-up of the room requiring a burner consuming 33 cubic feet of gas an hour to every three square feet of floor-area, the heat produced will always be more than sufficient to prevent the cooling of the interior.

The preceding figures show why most makers of heating-apparatus who have undertaken to warm halls or courts covered by sky-lights have only very imperfectly succeeded.

DWELLING-HOUSES.

103. Among the appendages of dwelling-houses which most often give out disagreeable smells should be placed, in the first rank, yards, kitchens, and privies. In consequence of the draught exerted by the chimneys of rooms near these places, it often happens that at certain times more or less infectious air is drawn into the apartments.

To avoid this serious trouble, it is necessary, by means of proper arrangements, which should also be simple, to produce a regular and almost constant motion of air from the apartments or the halls toward these places, discharging from them to the exterior. This may be accomplished in several ways.

104. Court-yards of dwelling-houses.-Apartment-houses, especially in Paris, very often contain little yards, belonging to the stores on the ground-floor, which seriously affect the healthfulness of the upper stories. Provision-stores, restaurants, dye-houses, drug-stores, &c., give rise to disagreeable or injurious smells, which rise and annoy the occupants of the house and injure the property.

These disagreeable effects may easily be overcome in the following way: The yard should be covered, in whole or in part, with a glass roof, forming a single inclined plane between the ground-floor and the second story. In an angle, and at the upper part of this roof, should be placed a chimney, extending above the upper cornice, the section of which should be calculated so that with a velocity of about three feet a second the air of the court-yard will be renewed once, or, better, twice an hour. At the lower part of this chimney should be placed a gas-burner, cousuming only 3 cubic feet an hour. The velocity being small and the chimney high, about 1,800 or 2,000 cubic feet of air may be carried off in an hour by this chimney to every cubic foot of gas burned, and thus a constant purification of the yards be secured.

When local arrangements favor, it will only be necessary, in order to keep up the draught, to carry a smoke-pipe up the chimney, or to start a fire in a coke-stove placed in it.

105. Kitchens.—When ranges with hot-air passages, such as are now in general use, are employed, it will be easy when they are put up to place hot-water pipes around the grate, and carry them a certain distance up the chimney and back to the range, as in the boilers of hot-water heating-apparatus, which would secure a sufficient draught.

106. Use of gas-burners for the ventilation of kitchens-In kitchens lighted by gas, when the ranges are already put up in the usual way, lighting one or two gas-burners at the bottom of the chimney, to be kept burning only while cooking is going on, would in most cases suffice to produce a draught sufficient to carry off all smell.

Example. The kitchen for a single flat in Paris is considered quite large if 10 feet long, 13 feet wide, and 115 feet high; that is, with a content of 1,490 cubic feet.

It follows from direct experiment that, with the aid of a single gasburner, consuming 13 feet an hour, and kept burning only while the meals are being prepared, that is to say, at most six hours a day, there may be produced every hour, with sheet-iron ventilating-pipes 91⁄2 inches in diameter, and

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which, added to the natural ventilation produced by the kitchen fire, will fully suffice to change the air of such a kitchen more than once an hour.

The expense for a whole year for one small gas-burner, consuming 14 feet of gas an hour, and burning six hours a day, would be 83 cubic feet a day, or 3,100 cubic feet a year, which, at the rate of $1.70 a thousand feet, would cost $5.27, a very moderate expenditure for getting rid of a nauseous smell, which would otherwise be experienced twice a day.

It may be added that the preceding results relate to metal pipes placed on the outside and exposed to cooling, while, in general, similar ventilating-pipes may be, and ought to be, made of earthen ware, and placed in the thickness of the walls or in the interior of buildings, which, exposing them less to cooling, would increase the effect obtained. In the case of large kitchens with wide fire-places, when the ranges are kept very hot, and are used almost all the time, it would be more economical to place a coal-grate in the lower part of the chimney, at about the top of the fire-place, and this would also be the most simple and direct method for country-houses.

107. Use of the lost heat from kitchen-ranges for ventilating and for heating baths.-Besides the advantage of securing a change of air and the removal of bad odors from the kitchen, the hot-water pipes mentioned in § 105 serve to supply baths, which may be established with success, as mentioned in § 81 in barracks, as well as in those establishments where provisions are cooked for the poor, to be distributed to them gratuitously or sold to them at a low price. The addition of hot-water baths to these useful establishments might thus be made at very little expense.

An arrangement of this kind is adopted with success in the new lying. in house established by the administration of public assistance, rue du Faubourg St. Jacques, to utilize the lost heat from the stoves used for making plasters.

108. The baths may be heated also by means of ordinary hot-air kitchen-ranges without recourse to the use of hot-water circulation, or, what is better, by combining the two means of utilizing the heat lost from the range during the time the meals are being prepared.

109. Privies.-The necessary arrangements to be made in order to prevent the infection which these attachments to buildings often produce vary with the mode of construction adopted and the nature of the building.

The regulations for the construction of privy-wells are as follows: The down-pipes should dip at their lower end into the contents of the well, or better into a fixed or movable copper basin, into which it is well when it can be done to force water from time to time in order to wash it. It follows from these arrangements that the only gases which can

ascend in these pipes arise from their internal surface or at the bottom of the pipes, and will not be very abundant, (Fig. 30.)

To prevent the gases from spreading to the interior of the rooms, water-closets called English closets are usually employed within dwellings. In less particular houses and in public establishments, there is simply placed under the opening a basin called Roger Mothe's apparatus, which tips and empties itself by the weight of the contents alone, and then returns and closes the opening.

These convenient means are not always sufficient to prevent the introduction of bad smells on account of small cracks in the joints of the apparatus.

In all cases it is better to keep the seat 1 or 2 inches above the upper edge of the bowl, letting the front and the two sides reach to the seat and to connect this space with a ventilating-pipe extending above the roof.

If this pipe can be placed near a source of regular heat, such as the kitchen-flue, or if hot water pipes can be carried into it, as in the case of mansions heated by hot water, it would be easy to obtain a sufficiently powerful draught in this pipe.

But if this method is not available, as often is the case in small dwellings, the same effect may be secured by placing in the pipe a small gasburner, burning at most 1 or 1 cubic feet an hour, and which, by the aid of a transom, will illuminate the closet at the same time that it purifies it. A common lamp might even be made use of, burning or ounce of oil an hour, (about to of a pint.)

[graphic]

36

The ventilating-pipe should be about from 46 to 62 square inches in area, and the small burner, burning 1 cubic feet an hour, would, in most cases, secure the renewal of 1,000 cubic feet of air an hour, which would suffice not only to expel all the gases coming from the seat and its descending-pipe, but even to renew the air of the room several times an hour by drawing in that of the surrounding corridors and also prevent the infection of the interior of the house.

110. Example.-Office of the Northern Railroad Company, (Fig. 31.)—If, instead of English water-closets, only open seats are used, or even those called Turkish seats, similar arrangements would produce the same results.

Fig. 31 shows the plan adopted with success in the office of the Northern Railway Company, where there are in the five stories twentyseven water-closets. The down-pipes serve for all the pairs of seats in each story, and are only three in number. They are 9 inches in diame

ter, and terminate in the movable copper water-basins, which form siphon-traps and prevent the rising of the gas from the well.

FIG.31.

[graphic]
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All the ventilating-pipes from the seats are 4 inches by 16 inches inside. They terminate in a large vertical collecting-pipe, about 10 square feet in sectional area, serving as a ventilating-chimney, in which are placed vertical hot-water pipes, which in winter produce a general draught. In summer, when the heating is interrupted, the draught is produced by gas-burners kept burning in each closet.

Ventilation by means of hot-water circulation can evidently be kept up in summer by means of a separate fire for this special

purpose, which would be more economical than the use of gas.

The result of experiments made in February, 1863, was that the amount of air removed for each seat under the action of the draught, produced simply by an excess of 70 to 130 of temperature in the chimney over that of the external air, was more than 2,200 cubic feet an hour. Although much greater than is generally necessary, this amount would not seem excessive in similar cases where, in addition to the seats, urinals, often imperfectly rinsed, are used.

111. Arrangement adopted at Lariboisière Hospital, (Fig. 32.)-In this establishment, the closets on each floor contain three seats, with bowls,

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