11 10 COTTAGE, FARM, AD VILLA ARCHITECTURE. whereas we have proved Methleys fireplace, fig. 1843, for nearly six years. Circular flues mij^ht readily be built, in a winding or zigzag direction, perfectly smooth in the inside, and at a comparatively small expense, by using sections of earthenware pipes as suggested, § 4fi3 ; and, to render the walls containing such flues perfectly strong, they might be built with mortar of a superior description, or with Roman cement. A pecu- liar form of bricks for this purpose has been invented by Iliort, but they are found much too expensive ; another and a very superior kind, which, from their shape, have the great advantage of bonding in with the wall, have been invented by Chadley, and deserve to come into general use. However, were Roman cement used in building the walls con- taining flues, whether these walls were constructed of brick or stone, flues might easily be formed circular in the section, and with perfect strength, by carrying them up round a flexible mould, or leathern bag filled with sand, drawn up the flue as it proceeded. One great use of circular flues is, that whatever may be their direction, they are easily swept without the aid of climbing boys. About London, where houses are almost always built on ground only held on lease for sixty or a hundred years, the thick walls containing the flues are generally the weakest in the building, instead of being, as they ought to be, the strongest ; and hence the great danger which exists, not only of their tumbling down, but of their being penetrated by fire. Were such walls built with Roman cement, though hollow, they would be as strong and perhaps stronger than if they were solid. Nothing is more to be desired than that some mode of constructing flues should be generally adopted, which would render climbing boys unnecessary ; and this, the government might easily effect in all houses to be built, with very little addi- tional expense to the builder, by enacting that all flues should be built circular, and be perfectly smooth inside. This is a point which, we have no doubt, will be attended to as it deserves, by the public, in a very short time ; and, when this is the case (as with every thing else which the public decidedly wills), it will become law. It is well known that (all other circumstances being the same) the short chimney flues of garrets and cottages never draw so well as those of rooms which have very high chimneys. This is an undeniable fact; it was noticed by Franklin; and, as it concerns servants and poor people in every part of the world, it merits the particular attention of the Architect. How is the imperfect draught of short chimneys to be remedied ? On the same general principles which we have laid down ; viz., increasing the height of the chimney as much as possible (which is the reason why we have shown such high chimneys to most of our designs for cottages) ; adjusting the throat of the chimney to the quantity of air and smoke required to make the fire burn properly ; forming one or more bends in the flue, to prevent the smoke from being driven down by the wind, and to increase the draught (which has the additional advantage of preventing the rain from falling down perpendicularly, and car- rying the soot before it) ; but, above all things, by having an opening at the tops of the windows or near the ceiling, in each apartment, for the admission of e^'ternal air to supplv the draught. It may be laid down as an indisputable fact, that it is impossible to have all the doors and windows of an apai-tment very tightly fitted, and at the same time to have the fireplace draw well, without the addition of such openings as have been mentioned, or of an underground air flue, and a communication between it and the hearth. As this would occasion too much trouble and nicety in the constniction of common cottages, nothing remains in the case of such dwellings, but to provide openings close under the roof, or over one door or window in each apartment, for a sufficient supply of external air. These openings may be furnished with shutters so as to regulate them at pleasure ; but, as even this might be too mucli trouble to a common cottager, the simplest mode is for him to push down the upper sash of his window an inch or two, or to open his outer door to the same extent. The whole of this subject merits the attentive consideration of the architectural critic ; who will find, that, in proportion to the perfection of the fitting and finishing of doors and windows, in the same proportion is the risk created of having smoky chimneys. 2192. Ventilation Is a subject intimately connected with that of the preceding para- graph. The perfection of ventilation consists, not in suddenly expelling the air from an apartment, and supplying its place with external air ; but in first gradually mixing the external air with that of the apartment to be ventilated, and next in carrying off this mixture by degrees, and supplying, by degrees, a fresh mixture in its place. When warm air is to be mixed with cold air, the latter ought to be admitted from above, in order that it mav descend, and intermingle with the former : on the contraiy, when cold air is to be mixed with warm air, the latter ought to be admitted from below to intermingle with the cold air in ascending. Hence, for the first purpose, the best practical mode of venti- latin<» a room is to have all the windows carried up as close to the ceiling as is prac- ticable ; and, when the air of the room is to be cooled, simply to slide down the upper sash of the window or windows, for a very small space, which, in few rooms, need exceed an inch for each window. When the air of a room is colder than the external air, and
