VILLAS IN VARIOUS STYLES. 865 boarded floors, and substituting earthenware tiles, plain or ornamented, according to the character of the house. 1530 1788. Mr. Frost's Plan for constructing fire-proof Buildings is, to form the floors of hollow earthenware tubes embedded in cement, and combined in such a manner as to be, in effect, one artificial flag-stone of the size of the room. These hollow tubes, for which Mr. Frost took out a patent some years ago, are square in the section, about an inch and a half on the side externally, with a tubular space of an inch and a quarter on the side internally. They are formed of brick earth, prepared in a superior manner, and pressed through moulds by machinery. The tubes are each about two feet long ; and the mode of forming a floor or roof of them is as follows ; — The centring, after being prepared and fixed in the usual manner, is first covered with a coating of cement of a quality suflSciently fine to form the ceiling of the apartment to be floored over ; and, if it is desired that there should be mouldings or ornaments in this ceiling or its cornices, moulds for them can be placed iii the centring, so as to form a part of it. One, or, in some cases, two coats of cement being laid over the centring, a stratum of the square tubes, laid side by side, and breaking joint, is next to be bedded in fine cement, and the interstices between them also filled in with that material. One thin coating of cement is then laid over the whole stratum ; and, in a week, when this is dry, another stratum of tubes is laid over the first, in a contrary direction, bedded and filled in with cement as before, and finished by a coating of the same material ; which, when dry, may have a second coating to serve as the floor of an apartment, or the covering of a roof, as the case may be. Where the space to be covered is not wider than ten feet, Mr. Frost conceives, and indeed has found upon trial (at a house. No. 6, Bankside, London, where he resided when he explained to us his process), that two strata of tubes would be sufficient ; but for greater widths he would employ three, four, or half a dozen strata ; or he would introduce iron girders to support artificial flag-stones of less thickness. There can be little doubt of the success of this plan ; but, as both cast and wrought iron are now so cheap, a simpler and less expensive mode is to tie cast-iron or stone abutments together with wroughl>iron rods, and to form the flooring or roofing between by four-inch brick arches, or layers of plain tiles bedded in cement. Flat roofs and floors of immense strength are formed in this manner, in and about London. Near us, at Bayswater, there is a public house with a flat roof so formed, which, on Sundays and other holidays, is crowded with guests ; and a veranda, ten feet broad, with a flat roof formed of two courses of tiles bedded in cement, is brought to a level at top with that material, and supports as many persons as can sit upon it. 1789. Fire-proof Floors and Roofs formed of Arches of Coomhs or EartJienware Pots, This is an old French invention, described in the Mechanics' Magazine, vol. viii. p. 354, as having been 'adopted in that architectui'al deformity the new palace at Pimlico. There the arches are formed of hollow pots, as being lighter than solid bricks. These arches spring from stone abutments which rest on the flanges of iron girders placed five feet apart. The length of the cast-u-on girders is from twenty to thirty feet. The pots are like flower-pots, but are without rims ; they are four inches in diameter at the mouth, and six inches deep outside measure ; the diameter at the bottom is such as that, in an arch of five feet span, the rise in the centre may not be more than six inches. The S H
