Chimneys (Smoky). A chimney which smokes at the wrong end is a great nuisance ; a cause of discomfort, vexation, and annoyance to all who are forced to live near it; and it is not surprising that very numerous attempts have been made to find a remedy. We have what are called wind-guards, reverberators, and all sorts and shapes of chimney-pott, to the great disfigurement of our houses: but these are mere expedients which might be avoided.
The best way to prevent a chimney smoking at the wrong and is to build it properly at first, or to alter it on some sound and practical plan.
The great cause of smoky chimneys is that they are made too wide at their lower end, where they come down and meet the fire-place; for years it has been the practice to leave an opening the whole width and depth of the fire-place, from which the smoke rushes out and half blinds or stifles those who are sitting by the fire. How often do we see a board, or a strip of tin, or a narrow curtain hung under the mantelpiece, to keep the smoke from being troublesome. But besides this annoyance, these wide-mouthed chimneys waste more than half the heat of the fire; for, instead of coming out and warming the room as it ought to do, the beat rushes at once up the chimney and so is lost.
Although a large open fire-place helps in keeping a room ventilated, it is further objectionable because of the draughts which it creates. In old-fashioned houses, people are obliged to use screens and many other contrivances to shelter themselves from the currents of air which come from all quarters, to give stiff-necks, ear-aches, and other unwelcome twinges to those who sit near the great cavern tailed a fire-place, where they are scorched on one side and frozen on the other. With such arrangements, a room never can be warm, because the air rushes away so fast that the walls have never time to get heated, and at a distance from the fire are as cold as out of doors.
A good deal of the inconvenience of smoke might be avoided by the proper management of a tire. Count Rumford observes "Nothing can be more perfectly void of common sense, and wasteful and slovenly at the same time, than the manner in which chimney tires, and particularly where coals are burned, are commonly managed by servants. They throw on a load of coals at once, through which the flame is hours in making its way; and frequently it is not Without much trouble that the fire is prevented from going quite out. During this time no heat is communicated to the room; and what is still worse, the throat of the chimney is occupied merely by a heavy dense vapour, not possessed of any considerable degree of heat, and consequently not having much elasticity. The current of warm air from the room which pre into the chimney, crosses upon the current
Of heavy smoke which rises slowly from the fire, obstructs it in its ascent, and beats it back into the room; hence it is that chimneys so often smoke when too large a quantity of fresh Coals is put upon the lire So many coals should never be put upon the tire at once as to prevent the free passage of the flame between them. In short, a fire should never he smothered; and when proper attention is paid to the quantity of coals put on, there will be very little use for the poker; and this fact will contribute very much to cleanliness, and to the preservation of furniture."
The Count devoted much attention to household economy generally, and as we know of no better plans for curing or preventing a smoky chimney and Baring fuel than his, we shall endeavour to give such a simple account of them as will enable any working-bricklayer or mason either to build a new chimney properly, or to alter an old one on correct principles.
Generally speaking, it will be necessary to diminish the opening of the fire-place - that is, to make it smaller; and to fix the grate more forward and less high than has been the practice. Sometimes a straight stone slab placed all across under the mantel, or a row of bricks supported by a flat iron bar, will be sufficient to effect a cure; for this lowers the breast of the chimney, and diminishes the size of the opening of the fire-place, The breast of a chimney is that
part against which the mantel is built, and a pood deal depends on the way on which this is finished on the inside. Then, if we wish smoke to ascend easily, we must place the throat, or lower part of the chimney, immediately over the fire; the back of the fire-place also should be built perpendicular. There is no more reason why smoke should refuse to ascend a properly-constructed chimney, than that water should refuse to descend through a pipe. And it will be seen from the diagrams that these improvements can be made with but a small amount of trouble.
Figure 1 shows a fire-place and part of the chimney as usually built; an opening with square sides, in which the grate is fixed so far back that most of the heat is lost. The depth, however, from back to front should not be more than from 9 to 13 inches; the back is, therefore, to be built up, as shown at figure 2, and in the ground plan, figure 4. It will be seen that the chimney breast has a small piece added to lower it.