THE plague of a smoking chimney is proverbial; but there are many other very great defects in open fireplaces, as they are now commonly constructed in this country, and indeed throughout Europe, which, being less obvious, are seldom attended to; and there are some of them very fatal in their consequences to health; and, I am persuaded, cost the lives of thousands every year in this island.
Those cold and chilling draughts of air on one side of the body while the other side is scorched by a chimney fire, which every one who reads this must often have felt, cannot but be highly
Strongly impressed as my mind is with the importance of this subject, it is not possible for me to remain silent. The subject is too nearly connected with many of the most essential enjoyments of life not to be highly interesting to all those who feel pleasure in promoting or in contemplating the comfort and happiness of mankind. And without suffering myself to be deterred either by the fear of being thought to give to the subject a degree of importance to which it is not entitled, or by the apprehension of being tiresome to my readers by the prolixity of my descriptions, I shall proceed to investigate the subject in all its parts and details with the utmost care and attention. And first with regard to smoking chimneys.
There are various causes by which chimneys may be prevented from carrying smoke, but there are none that may not easily be discovered and completely removed. This will doubtless be considered as a bold assertion; but I trust I shall be able to make it appear in a manner perfectly satisfactory to my readers that I have not ventured to give this opinion but upon good and sufficient grounds.
Those who will take the trouble to consider the nature and properties of elastic fluids, - of air, -
smoke, - and vapour, - and to examine the laws of their motions, and the necessary consequences of their being rarified by heat, will perceive that it would be as much a miracle if smoke should not rise in a chimney, (all hindrances to its ascent being removed,) as that water should refuse to run in a syphon, or to descend in a river.
The whole mystery, therefore, of curing smoking chimneys, is comprised in this simple direction, - find out and remove those local hindrances which forcibly prevent the smoke from following its natural tendency to go up the chimney; or rather, to speak more accurately, which prevent its being forced up the chimney by the pressure of the heavier air of the room.
Although the causes by which the ascent of smoke in a chimney may be obstructed are various, yet that cause which will most commonly, and I may say almost universally, be found to operate, is one which it is always very easy to discover, and as easy to remove, - the bad construction of the chimney in the neighbourhood of the fireplace.
In the course of all my experience and practice in curing smoking chimneys, - and I certainly have not had less than five hundred under my hands, and among them many which were thought to be quite incurable, - I never have been obliged, except in one single instance, to have recourse to any other method of cure than merely reducing the fireplace, and the throat of the chimney, or that part of it which lies immediately above the fireplace, to a proper form and just dimensions.
* Eves and Sutton, bricklayers, Broad Sanctuary, Westminster, have alone altered above ninety chimneys. The experiment was first made in London at Lord Palmerston's house in Hanover Square; then two chimneys were altered in the house of Sir John Sinclair, Baronet, President of the Board of Agriculture; one in the room in which the Board meets, and the other in the Secretary's room; which last being much frequented by persons from all parts of Great Britain, it was hoped that circumstance would tend much to expedite the introduction of these improvements in various parts of the kingdom. Several chimneys were then altered in the house of Sir Joseph Banks, Baronet, K. B., President of the Royal Society. Afterwards a number were altered in Devonshire House; in the house of Earl Besborough, in Cavendish Square, and at his seat at Rockhampton; at Holywell House, near St. Alban's, the seat of the Countess Dowager Spencer; at Melbourne House; at Lady Templeton's, in Portland Place; at Mrs. Montagu's, in Portman Square; at Lord Sudley's, in Dover Street; at the Marquis of Salisbury's seat, at Hatfield, and at his house in town; at Lord Palmerston's seat in Broadlands, near Southampton, and at several gentlemen's houses in that neighborhood; and a great many others; but it would be tiresome to enumerate them all, and even these are mentioned merely for the satisfaction of those who may wish to make inquiries respecting the success of the experiments.
Those who are acquainted with the principles of pneumatics, and know why the warm air in a room rushes out at an opening made for it at the top of a window when colder air from without is permitted to enter by the door or by any other opening situated lower than the first, will see that it would be quite impossible to ventilate a room in the complete and expeditious manner here described, where the air in a room is partially warmed, or hardly warmed at all, and where the walls of the room, remote from the fire, are constantly cold; which must always be the case where, in consequence of a strong current up the chimney, streams of cold air are continually coming in through all the crevices of the doors and windows, and flowing into the fireplace.
But although rooms furnished with fireplaces constructed upon the principles here recommended, may be easily and most effectually ventilated (and this is certainly a circumstance in favour of the proposed improvements), yet such total ventilations will very seldom, if ever, be necessary. - As long as any fire is kept up in the room, there is so considerable a current of air up the chimney, notwithstanding all the reduction that can be made in the size of its throat, that the continual change of air in the room which this current occasions will, generally, be found to be quite sufficient for
Though a room be closed in the most perfect manner possible, yet, as the quantity of air injured and rendered unfit for further use by the respiration of two or three persons in a few hours is very small compared to the immense volume of air which a room of a moderate size contains; and as a large quantity of fresh air always enters the room, and an equal quantity of the warm air of the room is driven out of it every time the door is opened, there is much less danger of the air of a room becoming unwholesome for the want of ventilation than has been generally imagined; particularly in cold weather, when all the different causes which conspire to change the air of warmed rooms act with increased power and effect.
All these advantages, attending the introduction of the improvements in fireplaces here recommended, are certainly important, and I do not know that they are counterbalanced by any one disadvantage whatsoever. The only complaint that I have ever heard made against them was that they made the rooms too warm; but the remedy to this evil is so perfectly simple and obvious, that I should be almost afraid to mention it, lest it might be considered as an insult to the understanding of the person to whom such information should be given; for nothing surely can be conceived more perfectly ridiculous than the embarrassment of a person on account of the too great heat of his room, when it is in his power to diminish at pleasure the fire by which it is warmed; and yet, Before I proceed to give directions for the construction of fireplaces, it will be proper to examine more carefully the fireplaces now in common use; - to point out their faults; - and to establish the principles upon which fireplaces ought to be constructed.
The great fault of all the open fireplaces, or chimneys, for burning wood or coals in an open fire, now in common use, is, that they are much too large; or, rather, it is the throat of the chimney, or the lower part of its open canal, in the neighborhood of the mantle and immediately
Were it my intention to treat my subject in a formal scientific manner, it would doubtless be proper, and even necessary, to begin by explaining in the fullest manner, and upon the principles founded on the laws of nature, relative to the motions of elastic fluids, as far as they have been discovered and demonstrated, the causes of the ascent of smoke; and also to explain and illustrate upon the same principles, and even to measure or estimate by calculations, the precise effects of all those mechanical aids which may be proposed for assisting it in its ascent, or rather for removing those obstacles which hinder its motion upwards; but as it is my wish rather to write a useful practical treatise than a learned dissertation, - being more desirous to contribute in diffusing useful knowledge by which the comforts and enjoyments of mankind may be increased, than to acquire the reputation of a philosopher among learned men, - I shall endeavour to write in such a manner as to be easily understood by those who are most likely to profit by the inform-
As the immoderate size of the throats of chimneys is the great fault of their construction, it is this fault which ought always to be first attended to in every attempt which is made to improve them; for however perfect the construction of a fireplace may be in other respects, if the opening left for the passage of the smoke is larger than is necessary for that purpose, nothing can prevent the warm air of the room from escaping through it; and whenever this happens, there is not only an unnecessary loss of heat, but the warm air which leaves the room to go up the chimney being replaced by cold air from without, the draughts of cold air, so often mentioned, cannot fail to be produced in the room, to the great annoyance of those who inhabit it. But although both these evils may be effectually remedied by reducing the throat of the chimney to a proper size, yet in doing this several precautions will be necessary. And first of all, the throat of the chimney should be in its proper place: that is to say, in that place in which it ought to be, in order that the ascent of the smoke may be most facilitated; for every means which can be employed for facilitating the ascent of the smoke in the chimney must naturally tend to prevent the chim-
But there is another circumstance to be attended to in determining the proper place for the throat of a chimney, and that is to ascertain its distance from the fire, or how far above the burning fuel it ought to be placed. In determining this point, there are many things to be considered, and several advantages and disadvantages to be weighed and balanced.
As the smoke and vapour which ascend from burning fuel rise in consequence of their being rarefied by heat, and made lighter than the air of the surrounding atmosphere; and as the degree of their rarefaction, and consequently their tendency to rise, is in proportion to the intensity of their heat; and further, as they are hotter near the fire than at a greater distance from it, it is clear that the nearer the throat of a chimney is to the fire, the stronger will be what is commonly called its draught, and the less danger there will be of its smoking. But on the other hand, when the draught of a chimney is very strong, and particularly when this strong draught is occasioned by the throat of the chimney being very near the fire, it may so happen that the draught of air into the fire may become so strong as to cause the fuel to be consumed too rapidly. There are likewise several other inconveniences which would attend the placing of the throat of a chimney very near the burning fuel.
Nothing is so effectual to prevent chimneys from smoking as diminishing the opening of the fireplace in the manner here described, and lowering and diminishing the throat of the chimney; and I have always found, except in the single instance already mentioned, that a perfect cure may be effected by these means alone, even in the most desperate cases. It is true, that when the construction of the chimney is very bad indeed, or its situation very unfavourable to the ascent of the smoke, and especially when both these disadvantages exist at the same time, it may sometimes be necessary to diminish the opening of the fireplace, and particularly to lower it, and also to lower the throat of the chimney, more than might be wished; but still I think this can produce no inconveniences to be compared with that greatest of all plagues, a smoking chimney.
But as these investigations are intimately connected with those which relate to the form proper to be given to the fireplace itself, we must consider them all together.
That these inquiries may be pursued with due method, and that the conclusions drawn from them may be clear and satisfactory, it will be necessary to consider, first, what the objects are which ought principally to be had in view in the construction of a fireplace; and secondly, to see how these objects can best be attained.
Now the design of a chimney fire being simply to warm a room, it is necessary, first of all, to contrive matters so that the room shall be actually warmed; secondly, that it be warmed with the smallest expense of fuel possible; and, thirdly, that, in warming it, the air of the room be preserved perfectly pure and fit for respiration, and free from smoke and all disagreeable smells.
In order to take measures with certainty for warming a room by means of an open chimney fire, it will be necessary to consider how, or in what manner, such a fire communicates heat to a room. This question may perhaps, at the first view of it, appear to be superfluous and trifling, but a more careful examination of the matter will
To determine in what manner a room is heated by an open chimney fire, it will be necessary, first of all, to find out under what form the heat generated in the combustion of the fuel exists, and then to see how it is communicated to those bodies which are heated by it.
In regard to the first of these subjects of inquiry, it is quite certain that the heat which is generated in the combustion of the fuel exists under two perfectly distinct and very different forms. One part of it is combined with the smoke, vapour, and heated air, which rise from the burning fuel, and goes off with them into the upper regions of the atmosphere; while the other part, which appears to be uncombined, or, as some ingenious philosophers have supposed, combined only with light, is sent off from the fire in rays in all possible directions.
With respect to the second subject of inquiry, namely, how this heat, existing under these two different forms, is communicated to other bodies; it is highly probable that the combined heat can only be communicated to other bodies by actual contact with the body with which it is combined; and with regard to the rays which are sent off by burning fuel, it is certain that they communicate or generate heat only when and where they are stopped or absorbed. In passing through air, which is transparent, they certainly do not communicate any heat to it; and it seems highly probable
In these respects they seem to bear a great resemblance to the solar rays. But in order not to distract the attention of my reader or carry him too far away from the subject more immediately under consideration, I must not enter too deeply into these inquiries respecting the nature and properties of what has been called radiant heat. It is certainly a most curious subject of philosophical investigation, but more time would be required to do it justice than we now have to spare. We must, therefore, content ourselves with such a partial examination of it as will be sufficient for our present purpose.
A question which naturally presents itself here is, What proportion does the radiant heat bear to the combined heat? Though that point has not yet been determined with any considerable degree of precision, it is, however, quite certain, that the quantity of heat which goes off combined with the smoke, vapour, and heated air, is much more considerable, perhaps three or four times greater, at least, than that which is sent off from the fire in rays. And yet, small as the quantity is of this radiant heat, it is the only part of the heat generated in the combustion of fuel burned in an open fireplace, which is ever employed, or which can ever be employed, in heating a room.
The whole of the combined heat escapes by the chimney, and is totally lost; and, indeed, no part of it could ever be brought into a room from an open fireplace, without bringing along
Now, the quantity of radiant heat generated in the combustion of a given quantity of any kind of fuel depends very much upon the management of the fire, or upon the manner in which the fuel is consumed. When the fire burns bright, much radiant heat will be sent off from it;
Nothing can be more perfectly void of commonsense, and wasteful and slovenly at the same time, than the manner in which chimney fires, 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, being occupied merely by a heavy dense vapour not possessed of any considerable degree of heat, and consequently not having much elasticity, the warm air of the room finds less difficulty in forcing its way up the chimney and escaping, than when the fire burns bright; - and it happens not unfrequently, espe
Those who have feeling enough to be made miserable by anything careless, slovenly, and wasteful, which happens under their eyes, who know what comfort is, and consequently are worthy of the enjoyments of a clean hearth and cheerful fire, should really either take the trouble themselves to manage their fires (which, indeed, would rather be an amusement to them than a trouble), or they should instruct their servants to manage them better.
But to return to the subject more immediately under consideration. As we have seen what is necessary to the production or generation of radiant heat, it remains to determine how the greatest proportion of that generated and sent off from the fire in all directions may be made to enter the
This must be done, first, by causing as many as possible of the rays, as they are sent off from the fire in straight lines, to come directly into the room; which can only be effected by bringing the fire as far forward as possible, and leaving the opening of the fireplace as wide and as high as can be done without inconvenience; and secondly, by making the sides and back of the fireplace of such form, and constructing them of such materials, as to cause the direct rays from the fire, which strike against them, to be sent into the room by reflection in the greatest abundance.
Now it will be found, upon examination, that the best form for the vertical sides of a fireplace, or the covings (as they are called), is that of an upright plane, making an angle with the plane of the back of the fireplace of about 135 degrees. - According to the present construction of chimneys, this angle is 90 degrees, or forms a right angle; but as in this case the two sides or covings of the fireplace
To have a clear and perfect idea of the alterations I propose in the forms of fireplaces, the reader need only observe, that, whereas the backs of fireplaces, as they are now commonly constructed, are as wide as the opening of the fireplace in front, and the sides of it are of course perpendicular to it and parallel to each other, in the fireplaces I recommend, the back (i k, Plate IX., Fig. 3) is only about one third of the width of the opening of the fireplace in front (a b), and consequently that the two sides or covings of the fireplace (a i and b k), instead of being perpendicular to the back, are inclined to it at an angle of about I35 degrees; and in consequence of this position, instead of being parallel to each other, each of them presents an oblique front towards the opening of the chimney, by means of which the rays which they reflect are thrown into the room. A bare inspection of the annexed drawings (Plate VIII., Fig. I, and Plate IX., Fig. 3) will render this matter perfectly clear and intelligible.
In regard to the materials which it will be most advantageous to employ in the construction of fireplaces, so much light has, I flatter myself, already been thrown on the subject we are investigating, and the principles adopted have been established on such clear and obvious facts, that no great difficulty will attend the determination of that
The best materials I have hitherto been able to discover are fire-stone, and common bricks and mortar. Both these materials are, fortunately, very cheap; and as to their comparative merits, I hardly know to which of them the preference ought to be given.
When bricks are used, they should be covered with a thin coating of plaster, which, when it is become perfectly dry, should be whitewashed. The fire-stone should likewise be whitewashed, when that is used; and every part of the fireplace,
I am well aware how much the opinion I have here ventured to give, respecting the unfitness of iron and other metals to be employed in the construction of open fireplaces, differs from the opinion generally received upon that subject; and I even know that the very reason, which, according to my ideas of the matter, renders them totally unfit for the purpose, is commonly assigned for making use of them; namely, - that they soon grow very hot. But I would beg leave to ask what advantage is derived from heating them?
I have shown the disadvantage of it; namely, - that the quantity of radiant heat thrown into the room is diminished; and it is easy to show that almost the whole of that absorbed by the metal is ultimately carried up the chimney by the air, which, coming into contact with this hot metal, is heated and rarefied by it, and, forcing its way upwards, goes off with the smoke; and as no current of air ever sets from any part of the opening of a fireplace into the room, it is impossible to conceive how the heat existing in the metal composing any part of the apparatus of the fireplace, and situated within its cavity, can come, or be brought, into the room.
There is, however, in chimney fireplaces destined for burning coals, one essential part, the grate, which cannot well be made of anything else but iron; but there is no necessity whatever for that immense quantity of iron which surrounds grates as they are now commonly constructed and fitted up, and which not only renders them very expensive, but injures very essentially the fireplace. If it should be necessary to diminish the opening of a large chimney in order to prevent its smoking, it is much more simple, economical, and better in all respects, to do this with marble, fire-stone, or even with bricks and mortar, than to make use of iron, which, as has already been shown, is the very worst material that can possibly be employed for that purpose; and as to registers, they not only are quite unnecessary where the throat of a chimney is
Register stoves have often been found to be of use; but it is because, the great fault of all fireplaces constructed upon the common principles being the enormous dimensions of the throat of the chimney, this fault has been in some measure corrected by them; but I will venture to affirm that there never was a fireplace so corrected that would not have been much more improved, and with infinitely less expense, by the alterations here recommended, and which will be more particularly explained in the next chapter.
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