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May 1, 1868.] THE CIVIL ENGINEER AND ARCHITECT’S JOURNAL. 143 horizontal pipe, it sends the noxious products back into the room. If chimney stacks were built of a uniform breadth from top to bottom, and a few spare flues provided, great facilities would be afforded for ventilation, and the supply of fresh air; while the whole building would gain in stability. Those spare flues should run right through from top to bottom of the house, and would be opened into or stopped off as occasion might require. There need be no recesses for the grates, as they would not be required with stoves constructed with the draught at the back ; and thus the whole bulk of the stack wouldbe little greater than at present. In building new houses in the country, and even in suburban villas, where the latter are erected under the direction of a com petent architect, there need be no difficulty in making such pro visions in the original building as will render a thorough and efficient system of ventilation certainly attainable. If however, the employer or his architect be misled by advertisements into using certain patented ventilating flues (which cotdd be named), or other contrivances put forth by people who are ignorant of the first principles of scientific ventilation, he can only render his house habitable at the expense of cutting them all out again. It will be perhaps as well to notice a circumstance which often occasions inconvenience, when special provi Inis have been made for the ventilation of the gas lights—the pipes intended to carry off the heated air and the products of combustion have frequently been found to bring cold air into the room, blowing back all the vitiated air and disturbing the lights. This effect will arise under any circumstances if the exterior orifice of the pipe be un protected from the wind, but as often happens from the absence of a proper arrangement for the supply to the apartment of an adequate quantity of fresh air. The chimney under these cir cumstances draws a portion of its supply from the pipe or flue intended for the ventilation of the lights. Unless the supply of fresh air be fully adequate, it will generally be safest to take the ventilating pipe from the gas lights into the chimney of the room. Complicated as the question of the extraction of vitiated air is found to be in practice, that of the means of introducing fresh air is even more difficult. The quantity of fresh air to be brought in is of course measured by .the rate of the extraction, and in making pro- visionforits admission into an ordinary room, the aggregate area of the inlets should be at least equal to the area of the chimney and other extraction channels, if there be any others. Not that the air would not find its way in if the former were considerably less, but it would rush in through the contracted passages with great velocity, as it may often be observed to do at keyholes and the crevices at the windows. It would even be better as tending to diminish draughts if the area of the inlet passages were con siderably in excess of the outlets ; and if the air on entering the room were as much diffused and broken up as possible. The places at which fresh air should be introduced into an apartment have been the subject of much discussion. Until of late it was almost universally the custom to let in the fresh air at, or near the floor; the practice of one or two engineers who early adopted a contrary course having been regraded in this re spect as erroneous. Latterly however, the persuasion has gained ground, that it is more advantageous to introduce the air at a higher level. Many large public buildings are now ventilated on this plan ; the different “ventilators” of Sherringham, Watson, Muir, McKennell, etc., are all constructed on this assumption ; and the Commissioners for the improvement of the sanitary con dition of barracks have generally directed the stopping up of fresh air inlets near the floor, and the formation of others in the upper part of the walls of the room. The great objection to inlets near the floor is the draught which they create, for the entering air, even although moderately warmed feels cold to anyone exposed to the current. On the other hand the precipitation of a sheet of cold air from the upper part of a room upon the heads of its occupants is anything but pleasant. Perhaps the safest plan would be to allow no inlets by which the external air could have direct access to the room, but such as are capable of being opened and closed at will, and which are always in sight. No “ ventilators ” are so convenient in this respect as ordinary window sashes, which, like the chimney, may therefore be regarded as an essential part of house ventilation. A full amount of supplementary inlets may then be provided, which should admit only warmed air in winter ; for it may be regarded as certain, that any inhabited apartment which depends for its ventilation in cold weather upon the direct admission of the external air, will be very badly ventilated indeed. And this brings us to the close connection between ventilation and warming. In large public buildings and mansions, the warmed air which serves also for ventilation is generally introduced into the rooms themselves, or at least into the principal of them, by warm air flues, or calliducts opening into the apartment. In the ordinary class of dwelling houses, however, this arrangement is seldom practicable, nor is it always desirable. The direct admission of external air to the rooms, otherwise than by the windows being inexpedient. It is better to derive the per manent supply from some part of the house to which it can be admitted fresh from the exterior without inconvenience ; and from which it can be distributed throughout the house. Such a place is to be found in most houses in moderate extent in the entrance hall or staircase, which may be made a great reservoir of fresh air, where it could be warmed or tempered in cold weather, and from which all the rooms would derive their supply. Generally any quantity of fresh air may be introduced to the hall or staircase by channels from the outside, or it might in rows of houses be brought down from above the roofs as already indicated, by flues constructed intheparty walls, and open ing at bottom below the place where the apparatus for warming the air might be fixed. Openings in a skylight or double current ventilators in a roof would not answer, because the air when it did come in by them could not be warmed; and if the hall and staircase were warmed independently, the current would be reversed, the warmed air would ascend the staircase to escape by the apertures at the top, the air from the rooms would be drawn out into the staircase, and the chimneys would be made to smoke. When once the hall and staircase are fully supplied with warmed air, as almost all the rooms of the house open into the hall, staircase, or contiguous passages, all that is wanted is to provided apertures in the internal walls for the admission of air into those rooms. In the reception rooms it would probably be most convenient to make the inlets in the upper part of the wall behind a perforated cornice, which should run the whole length of one side of the room; and it would be better if the side at which the air is admitted be opposite the fireplace. A per forated cornice at the opposite end might communicate with a spare flue : in the chimney stack, and would serve for the ex traction of air from the upper part of those rooms in which gas was burnt. For the bedrooms and secondary apartments the air might be admitted without the mode exciting the observation of any one, simply by leaving a space between the lintel, and the soffit of the door linings, cutting back the jambs, and keeping the architrave at top, a little forward. An inlet would thus be formed, nearly the whole breadth of the door, by an inch to two inches in width ; which would be sufficient to keep a bedroom thoroughly aired, even without a fire. The comfort of a house thus ventilated and warmed must have been experienced to be appreciated. A healthy atmosphere constantly renewed, at an agreeable temperature, pervading the whole habitation; foul air from drains excluded; the smell of the kitchen and offices con fined to the proper localities ; smoky chimneys prevented; the oppressiveness of rooms lighted by gas in the evening counter acted ; and the pleasure of retiring at night to a comfortable and well ventilated bedroom, are among the advantages to be gained by the adoption of a simple, but well considered system of ventilation 'with warming. Excavations at Pompbu.—The excavations, which are being earned on with great activity just now at Pompeii, have brought to light two very interesting specimens of ancient art, namely, two fres- coe portraits, situated under a portico of the Via Stabiana. They are believed to be the master and mistress of the house. The man wears the toga of magistrate, and the woman is represented in the attitude of a person reflecting about what she is to write, for she has a style in her right hand and is about to carry it to her lips, while in her left she holds the writing tablets. Both the portraits are well executed. Statue to the late Painter, Ingres.—A competitive exhibition of models for a statue of the late painter, Ingres, is about to take place at the Institut of France. More than thirty models have arrived, some from Rome and other parts of Italy, and some from Athens, but the majority from the ateliers of Parisian sculptors. M. Ingres was not a favourable subject for sculpture, but the estimation in which he was held will probably have induced some clever sculptors to compete for the execution of the statue to be raised to his memory.