TESSELLATED FLOORS. Mr. Ward, in the Introductory Essay to Mr. Owen Jones's beautiful work on Mosaic Pavements, says :— " The materials of the best and costliest pavements at Rome (such, for example, as. those still remaining in the Baths of Cara calla) are coloured marbles of various kinds, differing considerably from each other in hardness and durability. The inferior pave ments, found scattered through Britain,France, and other parts of Europe, and along the western coast of Africa, are usually made of such coloured stones as the neighbourhood happened to supply; with the exception only of the red tesseree, which are almost invariably of burnt clay. Thus, in the celebrated Roman pavement which was discovered in 1793, at Woodchester in Gloucestershire, the gray tesserfe are of blue liar, found in the vale of Gloucester ; the ash-coloured tesserao of a kind of stone, often found in the same masses with the former ; the dark brown of a gritty stone, met with near Bristol, and in the Forest of Dean ; tho light brown of a hard calcareous stone, occurring at Lypiat (two miles from the site of the pavement) ;' and the red tesserce (as usual) of burnt brick." The tesserce, or small cubic pieces of the Roman pavements, are by no means uniform in shape and size; the fissures between them are wide:and irregular; and as these fissures aro filled up with ceteent, a muddy hue is given to the general tints.
In the beginning of tho present •century, Mr. Wyatt introduced the plan of inlaying stone tesserce with coloured cements. In later methods, terra cotta tessera:, have been inlaid in a similar way. Mr. Blashfield adopted the plan of forming the tesserfe of cements coloured with metallic oxides. Bitu men, coloured with metallic oxides, is another material employed. Mr. Singer introduced a plan of forming tesserce by cutting pieces of the required form out of thin layers of clay; which pieces are afterwards dried and baked, and united by a peculiar cement. In another
plan, adopted at the Worcester porcelain works, tiles of two colours are formed by pressing a device on slabs of clay, and pouring liquid clay of. another colour into a sunk device on the surface of the former.
In Mr. Prosser's method, small tessera) are formed by compressing porcelain powder into moulds with great force, in the manner de scribed. under BUTTON MANUFACTURE. The tesserfe may be of any colour—white, black, red, blue, yellow, brown ; and of any definite form—triangular, quadrilateral, rhomboidal, hexagonal, &a. In the formation of a floor or pavement with-such tesserce, the pieces are first put together in their proper order, placed downward on a smooth surface ; and as soon as a sufficient portion of the design is finished, it is backed with fine Roman cement, which is worked in to fill the crevices between the tesserce. The pavement is thus formed into smooth flat slabs of convenient size, which are laid down on any properly prepared foun dation.
Although it belongs more to inlaying or marquetry than to tessellated pavements, we may say a word or two concerning the beautiful floor of the new Coal Exchange. It is a cir cular floor 00 feet in diameter, and is formed of 4,000 pieces of wood, arranged into a star like pattern of great beauty, bearing some resemblance to a mariner's compass. All the wood formed portions of living trees within a short period pefore the floor was made; the pieces having been prepared by the Drying or Dessicating process of Messrs. Davison and Symington. In this respect the floor is an exemplar of a highly useful and important. manufacturing invention. The kinds of wood employed are ebony, black oak, red oak, com mon oak, white holly, mahogany, elm, red walnut, white walnut, and mulberry.