A CHIMNEY (See Plate CNC.) consists of an aperture in the wall, to receive a stove or grate, with fire to heat the apartment ; and on this account it is also named a Fire-place. From it a vacant space, named a vent, shaft, or flue, is carried, within the thickness of the wall, to the level of the top of the roof, to convey away the smoke. The bottom of the fire-place should be laid with square tiles, stone, marble, or an iron plate, in order to receive the cinders and ashes ; this is termed the Inner hearth. Upon a level with this, or a little above it, and immedi ately before the fire-place, a space equal in length to the breadth of the chimney, and about two feet in breadth, should be laid with the same sort of materials as the in ner hearth ; it is termed the Slab, and is laid either in a wooden boxing, containing sand and mortar, or upon a flat brick arch, which has been turned between the wall and a trimming-joist in the floor. The front and vertical sides of the chimney aperture are termed Jambs, and are composed of stone, marble, NVO0d, or iron. The part which reaches across the top of the aperture is called the 411an tie, and is of the same sort of materials as the jambs. As in thin walls, the part which the chimney occupies is pro jected into the loom, in this, what is over the chimney, is termed the Breast. Within the fire-place, the parts which reach between the jambs and back, are named Covings. Where the space is contracted from the size of the fire place to that of the flue, it is called the Gathering wings, or Throat. The portion of the chimney which rises above the roof, is named the Chimney top. 'Where several flues, either in the wall or at the top, approach very near each other, the partitions between them arc named If iths ; and the whole is termed a Stack. In rooms of ordinary dimen sions, the flues, in rough stone walls, are from 12 to 14 inches square ; in hewn stone or brick-work, about 10 by 14 inches; but the section must be enlarged in rooms of large dimensions, kitchens, &c. As soot is apt to gather in the angles of square flues, the circular form is prefer able. They should be made quite smooth within, and free of quick bendings. It is of advantage to have the
flues a great height ; but if raised much above the level of the roof, it is difficult to render them ornamental. Inigo Jones is the only British architect who has performed it with success.
As much of the comfort of an apartment depends up on its being free of smoke, and much economy in causing the heat to be reflected into the room, instead of suffer ing it to be unnecessarily absorbed by the materials, or dissipated in the flue, Sic. great attention is necessary in fitting up the fire-place. For economy, stone which will stand the fire, is preferable to metal. The side covings should be levelled, or wholly circular ; and the opening at the back of the fire-place into the throat should not exceed four inches in breadth ; frequently one inch and a half is sufficient. With register-stoves this can be regulated to great advantage. The throat part should fall back from this aperture, and, in general, no air should be admitted into the throat, but what passes over the fire ; it is therefore advisable to fit up the fireplace very accu rately, and place the front of the grate forward to the line of the face of the wall of the apartment. In countries where stoves are used, it is customary to place them al together before the face of the wall. This admits of much decoration, and also throws the greatest part of the heat into the room.
Chimneys have always been considered important fea tures, but the style of decoration has varied greatly in different ages. In the Norman castles, they were fre quently large, and accompanied by rude pillars, sculp tures, and ornamented mouldings. After the revival of Roman architecture, the whole space between the fire place and the ceilings, called the chimney breast, was co vered with architectural decorations of great labour and expence. Wood was succeeded by stucco work and or namented pannels, to receive paintings ; but of late these have been abandoned, and the chimney has been reduced into the smallest possible bounds, making it, for elegance, depend upon the marble dressings and highly polished and engraved steel register stoves.