Plates XX., XXI., and XXII., which illustrate two well-arranged houses erected from the designs of a London architect, Mr. E. J. May, have been introduced, with Mr. May's kind permission, for the purpose of showing what has been done in the way of designing houses with strict regard to their adequate ventilation.

Such complete schemes of ventilation could not, of course, be adapted, without very great cost, to existing buildings, but in the case of new houses there is no reason why ventilation should not be considered from the outset, and its requirements be allowed to modify, to some extent, the design and construction.

Probably neither of these houses would have been erected as shown in the Plates, had not Drs. Drysdale and Hayward carried out somewhat similar arrangements in their own homes in Liverpool in the years 1861 and 1867 respectively, and had they not given publicity to their principle in papers read by Dr. Hay-ward before the Liverpool Architectural Society in 1868, and before the Royal Institute of British Architects in London in 1873, and in a book entitled Health and Comfort in House-building, which first saw the light in 1872. The principles advocated by these doctors have been already set forth herein in the Section on Warming (pp. 104-7), and little need be added now. It must, however, be pointed out that they now disclaim all advocacy of warming houses by hot air; on pp. 27 and 28 of the third edition (1890) of their book, they make this clear: "We are no advocates of warming the house by mean.- of heated air. All we recommend here is the warming of the incoming air that is requisite for ventilation. . . . The attention paid here to the distribution of warm air has led to the erroneous impression that our book recommends the plan of warming the house by hot air."

It will be seen, therefore, that the house at Chiswiek, although directly receiving its initiative from the labours of the Liverpool doctors, went somewhat further, for it was an attempt to combine warming and ventilation. - that is to say, the air required for ventilation was to be warmed in the basement and distributed throughout the house as the sole wanning agent; the kitchen - fire, which of course was required for cooking, supplied the necessary heat to the surrounding fool-air Hue in order to create the up-current required to extract the vitiated air from the several apartments. This will be better understood by reference to the two Plates, and especially to the section and details given in Plat XXI. In the drawings no other fireplaces are shown, but Mr. May writes that fireplaces and Hues were built, but the fireplace-openings were bricked up and therefore Dot used

The fresh air was drawn into a special chamber in the basement, and there wanned by means of hot-water pipes slung to the ceiling of the chamber. Thence it passed through floor-gratings into the hall on the ground-floor, and the corridor on the first floor, and was then conveyed into the various apartment- through holes in the walls, near the floors and ceilings.

The extract-flues were in proportion to the cubic capacities of the rooms from which they led; thus, the flue from the consulting-room was 10 inches by 5 inches, that from the kitchen 9 inches by 9 inches, and those from the two bed-rooms shown in the section on Plate XXI. were 11 inches by 6 inches and 9 inches by 5 inches respectively. The main extract-flue surrounding the smoke-Hue had a clear area of 381 square feet, while the downcast-shaft leading to it had an ana of .572 square feet as in Dr. Hayward's house, the windows were "hermetically closed", in order that no cold air might find direct access to the rooms, but that all the air required must pass through the wanning chamber in the basement. In Dr. Drysdale's house - the earliest of the three - the windows were simply "close-fitting", but apparently the experience gained here led to the "hermeti-cally-closed" windows of his friend Dr. Hayward's house, and later to those of Dr. Hogg's house at Chiswick,shown in Plates XX. and XXI.

There are several serious objections to such a combined system of warming and ventilation, especialally when the windows are "hermetically closed" and fireplaces are conspicuous by their absence. In the first place, there is a want of elasticity about the arrangements; for example, it is often desirable, particularly in summer, to secure a large inflow of air to a room after it has been unduly occupied, as in the case of a dining-room where, after a dinner, the gentleman have smoked abundantly; the best way of effecting the desired change of air is undoubtedly to open windows as wide as possible. In summer again, the currents of fresh air through the house, caused by open windows and doors, are often positively refreshing. In such a house as that at Chiswhick, no refreshing changes of air could be rapidly accomplished. Then again, at night.

when ventilation and fresh air are even more necessary than during the day. the out-doors will be closed, so that no air can find entrance except through the warming chamber, and the kitchen-fire will not he burning, so that the current in the extract-shaft will be often sluggish in the extreme, and the supply of fresh air to the rooms and the extraction of vitiated air will be imperffect Air-ducts, moreover, may become coated with dust and orgauie matter, and may actually pollute the air passing through them, unless they are so arranged as to admit of ready chaining, and unless the cleansing is regularlv done.

More might be said, but perhaps a quotation from Mr. Mays letter, with reference to the house at Chiswick, will suffice: "A family lived in it safely for four years, but I expect they found it dull comfort to have nothing but hot-air gratings to look at, and no usual draughts to grumble at, so at the end of that time the windows were made to open, and the fireplaces which I had had formed) opened out and used, thus bringing this house practically to the same scheme as the Hampstead one".

The Hampstead house is shown in Plate XXII., and undoubtedly avoids the principal defects of the earlier building. The drawing illustrates a pair of houses, but only the right-hand house includes the special arrangements for ventilation. The arrangements for the wanning of the incoming air and its admission to the several corridors and apartments, and for the extraction of the vitiated air by means of upcast flues leading to a foul air chamber in the attic, and thence by a main down-cast shaft to the basement, and up again by an extract-shaft surrounding the kitchen flue, are practically the same as those at Chiswick, but in addition to them, the windows are made to open, and fireplaces are provided as usual in the rooms and used when required.

This scheme appears to have worked satisfactorily: at any rate, Mr. May Lb able to write: "My client always said he derived great benefit and comfort from the system". Undoubtedly it possesses merits which were wanting in the other house, notably the merit of elasticity. If, in case of sickness, the temperature of any room requires raising, it can be done by means of the open fire provided in that room; increased ventilation can at any time be quickly provided by opening the windows, and additional warmth combined with greater extraction of air by lighting a fire in the grate.

Somewhat similar houses have been erected in various parts of the country, but it is certainly somewhat surprising that, after the lapse of more than 30 years from the erection of Dr. Drysdale's house in Liverpool, so few examples occur in which the principles have been carried out. Either houses as ordinarily built are not so bad as they are painted, or the proposed system has serious practical defects or architects and householders are grievously slow to learn. Perhaps all three reasons have something to do with the tardy adoption of the system. Mr. May although he has evidently studied the system closely, and has had practical experience in the working of it, is not by any means enthusiastic about it: he says: "I have never professionally advocated it, nor, since I built these houses, have I designed any others like them, nor do I expect to very much .

Another arrangement for supplying warm air to the several rooms of a building is shown in Plate XXIII. It has been designed by Mr. Wm. Bruce, whose gas-stoves or radiators have already been mentioned. In this larger apparatus also, gas is used as the heating medium, more or less "sections" of the apparatus being used according to the work to be done. The illustration shows ten of these sections enclosed in a chamber of glazed brickwork. Access-door are provided. A separate supply of air is conveyed to the burners by means of the pipes marked m, and a special Hue J is constructed for carrying off the products of combustion.

The air to be wanned is brought from the exterior through the large duct c, in which arc placed three filtering screens D. A fan is sometimes inserted at B for propelling the air. and when this is in use the flap f is lowered to the position shown by the dotted lines. Between the fan and the warming chamber, water, mixed with disinfectants if desired, can be sprayed through the incoming air. so as to purify it still more; this is effected by means of the two cylinders marked G; on the end elevation, and the adjacent pipes. After passing through the warming chamber, the air is led along the ducts kkk to the various apartments.

This apparatus provides means for purifying the air, and has other advan-tages, which should render it of considerable utility for ventilation, provided that suitable extract-shafts are provided, and that the air is properly humidified after being warmed.

Plats XX!!!.

ELEVATION ON LINE BB.

ELEVATION ON LINE BB.

SIDE ELEVATION.

SIDE ELEVATION.

LONGITUDINAL SECTION.

Supplementary Chapter By The Editor Ventilation By 50054Supplementary Chapter By The Editor Ventilation By 50055PLAN ON AA.

PLAN ON AA.

BRUCE'S WARMING AND VENTILATING APPARATUS, HEATED BY GAS.

C. Main air-duct. D. Screens. E. Fan.

G. Humidifying and disinfecting apparatus. H. Gas-inlets. J. Flue for waste products.

K. Ducts for heated air.

I. Ten "sectios" heatted by gas.

M Air-inlets to gas- burners.