P The passage under the false back and part of the hearth for the smoke.
The arrows show the course of the smoke.
Plate VIII*.
Vol. II. page 238.
Profile of the Pensylvania Chimney & Fire-Place.
Front View Staffordshire Fire-Place. Side View
Published as the Act directs, April 1, 1806, by Longman, Hurst, Rees & Orme, Paternoster Row.
The fire being made at A, the flame and smoke will ascend and strike the top T, which will thereby receive a considerable heat. The smoke, finding no passage upwards, turns over the top of the air-box, and descends between it and the back plate to the holes in the bottom plate, heating, as it passes, both plates of the air-box, and the said back plate; the front plate, bottom and side plates are also all heated at the same time. The smoke proceeds in the passage that leads it under and behind the false back, and so rises into the chimney. The air of the room, warmed behind the back plate, and by the sides, front, and top plates, becoming specifically lighter than the other air in the room, is obliged to rise; but the closure over the fireplace hindering it from going up the chimney, it is forced out into the room, rises by the mantle-piece to the cieling, and spreads all over the top of the room, whence being crouded down gradually by the stream of newly-warmed air that follows and rises above it, the whole room becomes in a short time equally warmed.