Chimney

an upright passage designed to carry away smoke and create a draft. It may be built of any non-combustible material, as brick, stone, or concrete. The design of the fireplace chimneys of the early settlers was brought from England. In wooded countries, they were built of short wooden logs, well plastered within with clay. Chimneys of stone masonry were a great improvement. The higher a chimney, the better the draft, as this depends on a difference in weight between the warm air of the chimney and the cold air on the outside. The enormous chimneys in connection with factories are built to a great height to secure draft. A concrete smokestack erected recently at Great Falls, Montana, is 506 feet high. Its diameter at the base is 78 feet; at the top, 55 feet. The dust, or soot, is caught on vertical wires from which it is shaken into hoppers at the bottom and dumped into cars in a pit beneath. This is probably the loftiest chimney in the world. If a chimney be too large to be heated it will not draw well. Masons formerly surrounded large chimneys with trestle work, but now build from the inside. Chimneys of a primitive sort were not unknown to the ancients, but the modern chimney may be regarded as an invention of western Europe.