and the occasional addition of a very small portion of water: this composition he calls the prepared material.
2. He constructs floors, walls, and all other buildings, according to this invention, in such a manner that the power of fire, from wood, coal, charcoal, coak, or other combustible matters, may be applied to the external and interior surfaces of the floors, walls, and other parts, by means of fires maintained in cavities left within, which he calls by the name of furnaces.
3. With respect to the particular forms, dimensions, and relative positions of the said floors, walls, and other parts of buildings, and the furnaces left or formed within the same, together with the apertures or communications, for the purposes of ventilating the fires, of suffering the volatile matters to escape, and of converting the whole into one entire mass of brick, by a due communication and continuance of heat, Mr. Walker says, the ground must be rendered solid, and the foundation laid in the usual manner; after which he applies a quantity of the prepared material before alluded to, and beats, rams, or presses it down to the thickness of about six inches; and in width, corresponding with the intended dimensions of the wall, regulated by boards or framing. He then plants upright, at the distance of about thirty inches asunder, in the said layer or bed of prepared material, a number of cylindrical pieces of wood, of about nine inches in diameter each, and eighteen or more inches in length, to serve as moulds for the cavities of the furnaces; and between each of such moulds he places, in the longitudinal direction of the wall, a number of pipes, of wood, or other materials, or rods, of combustible or incombustible matter, for the purpose of forming communications between all the several furnaces, or as many of them as he thinks proper. Then he proceeds to form another layer or bed of the material, to the same height, namely, about six inches, and disposes a number of such pipes, or rods, for the purpose of forming similar communications. In this manner, he constructs the whole, or so much of the wall as he apprehends, at the time, may be conveniently formed, in the raw or unburnt state; taking care, as the work advances, to raise the wooden cylinders, or moulds, that a sufficient portion of them may remain above the surface of the work, to admit of the reception and proper fashioning of each subsequent layer; or he forms the communications between the furnaces, by perforating the wooden moulds, in various places, at right angles to their respective axes; and through the said perforations he passes a bar of iron, or other material, which serves to connect three or more of the said furnace-moulds, and, being afterwards withdrawn, as the work proceeds, leaves cavities of communication, similar to those formed by pipes, rods, &c. in the manner before described. Farther, he opens such a number of horizontal or oblique apertures, or flues, into all the furnaces, and likewise into all the cavities, as may be requisite for admitting, on all sides, the access of atmospheric air. In some instances, he forms the horizontal or oblique apertures, or flues, by disposing, along with the pipes, a suitable number of taper rods, which are afterwards extracted.
4. When the wall is built, he either suffers it spontaneously to
dry,
