Architecture

"Though the saving of fuel which will result from the improvements to the forms of Chimney Fire-places here recommended will be very considerable, yet I hope to be able to show in a future Essay, that still greater savings may be made, and more important advantages derived from the introduction of improvements I shall propose in Kitchen Fire-places."

"[T]he height to which the new back and covings ought to be carried... will depend not only on the height of the mantle, but also, and more especially, on the height of the breast of the Chimney, or of that part of the Chimney where the breast ends and the upright canal begins.—The back and covings must rise a few inches, five or six... higher than this part, otherwise the throat of the Chimney will not be properly formed;—but I know of no advantages that would be gained by carrying them up still higher."

"Smoky chimneys in a new house are [as] such frequently from mere want of air. The workmanship of the rooms being all good... true and tight... The doors and the sashes too, being worked with truth, shut with exactness so that the room is as tight as a snuff-box."

"Those [grates] whose construction is the most simple, and... the cheapest, are beyond comparison the best, on all accounts.— Nothing being wanted in these Chimnies but merely a grate for containing the coal, and in which they will burn with a clear fire;—and all additional apparatus being, not only useless, but very pernicious, all complicated and expensive grates should be laid aside, and such as are more simple substituted in the room of them."

"I have been... particular in explaining these first principles, because for want of clear ideas respecting them, much fruitless expence has been occasioned... whole stacks having been pulled down and rebuilt with funnels of different forms, imagined more powerful in drawing smoke, but having still the same height and the same opening below, have performed no better than their predecessors."

"Now, if smoke cannot rise... unless other air be admitted to supply its place; and if therefore no current of air enter the opening of the chimney, there is nothing to prevent the smoke coming out into the room."

"The current of air, which, passing under the mantle, gets into the Chimney, should be made gradually to bend its course upwards, by which means it will unite quietly with the ascending current of smoke, and will be less likely to check it, or force it back into the room.—Now this may be effected with the greatest ease and certainty, merely by rounding off the breast of the Chimney or back part of the mantle, instead of leaving it flat, or full of holes and corners; and this... ought always to be done."

"And in the choice of a grate, as in every thing else, beauty and elegance may easily be united with the most perfect simplicity.—Indeed they are incompatible with every thing else."

"That air is so rarefied or expanded by heat, may be proved to... by a lank blown bladder, which laid before a fire will soon swell, grow tight, and burst."

"Having lit a pipe of tobacco, plunge the stem to the bottom of a decanter half filled with cold water; then putting a rag over the bowl, blow through it, and make the smoke descend in the stem of the pipe, from the end of which it will rise in bubbles through the water; and being thus cooled will not afterwards rise to go out through the neck of the decanter, but remain spreading itself, and resting on the surface of the water. This shews that smoke is really heavier than air; and that it is carried upwards only when attached to, or acted upon, by air that is heated, and thereby rarefied and rendered specifically lighter than the air in its neighbourhood."

"Another experiment may be, to take a glass tube... open at both ends, and fixed upright on legs, so that it need not be handled, for the hands might warm it: at the end of a quill, fasten five or six inches of the finest light filament of silk, so that it may be held either above the upper end of the tube or under the lower end, your warm hand being at a distance by the length of the quill. If there were any motion of air through the tube, it would manifest itself by its effect on the silk [Fig. I]; but if the tube and the air in it are of the same temperature with the surrounding air, there will be no such motion. ...Warm the tube, and you will find as long as it continues warm, a constant current of air entering below and passing up through it, till discharged at the top; because the warmth of the tube... rarefies that air, and makes it lighter than the air without, which therefore presses in below, forces it upwards, follows and takes its place, and is rarefied in its turn."

"Various have been the contrivances to avoid this: such as bringing in fresh air through pipes, in the jams of the chimney, which, pointing upwards, should blow the smoke up the funnel; opening passages into the funnel above, to let in air for the same purpose. But these produce an effect contrary to that intended; for, as it is the constant current of air passing from the room through the opening of the chimney into the funnel, which prevents the smoke coming out into the room, if you supply the funnel by other means, or in other ways, with the air it wants, and especially if that air be cold, you diminish the force of that current, and the smoke, in its efforts to enter the room, finds less resistance."

"If... a column of air, equal to the content of the funnel, must be discharged, and an equal quantity supplied from the room below; it will appear absolutely impossible that this operation should go on if the tight room is kept shut: for were there any force capable of drawing constantly so much air out of it, it must soon be exhausted, like the receiver of an air-pump, and no animal could live in it."

"[O]f above an hundred and fifty Fire-places which have been altered in this city, under my direction, within these last two months, there is not one which has not answered perfectly well. ...the saving of fuel, arising from these improvements of Fire-places, amounts in all cases to more than half, and in many cases to more than two thirds of the quantity formerly consumed."

"[T]he form of the breast of the Chimney is... of... great importance... The worst form it can have is that of a vertical plane, or upright flat;—and next... worst... is an inclined plane.—Both... cause the current of warm air from the room, which will... sometimes find its way into the Chimney, to cross upon the current of smoke, which rises from the fire, in a manner, most likely to embarrass it in its ascent, and drive it back.— The inclined plane which is formed by a flat register placed in the throat of a Chimney produces the same effects; and this is one reason, among many... which have induced me to disapprove of register stoves."

"In modern built houses where the doors and windows are... made to close with such accuracy that no crevice is left for the passage of the air from without... When there is a fire burning... as the air necessary to supply the current up the Chimney where the fire burns cannot be had in sufficient quantities... through the very small crevices of the doors and windows, the air in the room becomes rarefied, not by heat, but by subtraction of that portion of air which is employed in keeping up the fire, or supporting the combustion of the fuel, and in consequence of this rarefaction, its elasticity is diminished, and being at last overcome by the pressure of the external air of the atmosphere, this external air rushes into the room by the only passage left for it... by the open Chimney."

"I hope likewise to be able to show in an Essay on Cottage Fire-places, which I am now preparing for publication, that three quarters, at least, of the fuel which cottagers now consume in cooking their victuals, and in warming their dwellings, may with great ease, and without any expensive apparatus, be saved."

"Those who consider what an immense quantity of air is required to supply the current that sets up the chimney of an open fire place, where there is a fire burning, must perceive what an enormous loss of heat there must be, when all this expence of air is supplied by the warmed air of the room, and that all this warmed air is necessarily and constantly replaced by the cold air from without, which finds its way into the room, by the crevices of the doors and windows. But all this waste of heat, or any part... may be prevented by the scheme proposed, for if the air necessary to the combustion of the fuel, and to the supplying of the current up the chimney, be furnished by the air-tube, the warmed air in the room will remain in its places and as this will in a great measure prevent the cold currents from the crevices of the door and windows, the heat in the room will be the more equable, and consequently the more wholesome and agreeable on that account."

"[A]s it is an invariable rule among all fluids, that those which are lightest rise upwards, and at length swim upon the top of such as are more weighty... so... that when any particles of the same fluid are... rendered lighter, or more weighty, than other parts... they either rise to the top, and give place to the more dense and weighty parts of it, or sink to the bottom, and force the warmer fluid to the surface."

"It is owing to this cause that the water at the top of a caldron, before it begins to boil, is always as warm, or warmer, than what is below:—for the particles of water that touch the bottom are no sooner acted upon by the heat below, than they become warmer, and more expanded, than those immediately above them, and therefore rise directly upwards, and give place to denser cold particles, which are forced in their turn to ascend in like manner towards the top."

"Whether the new back and covings are constructed of stone, or... bricks, the space between them, and the old back and covings of the Chimney ought to be filled up... with loose rubbish, or pieces of broken bricks, or stones, provided the work be strengthened by a few layers or courses of bricks laid in mortar; but it will be indispensably necessary to finish the work where these new walls end... at the top of the throat of the Chimney, where it ends abruptly in the open canal of the Chimney by a horizontal course of bricks well secured with mortar."

"We leave it to the political arithmetician to compute how much money will be saved to a country, by its spending two thirds less of fuel; how much labor saved in cutting and carriage of it; how much more land may be cleared by cultivation; how great the profit by the additional quantity of work done, in those trades particularly that do not exercise the body so much, but that the workfolks are obliged to run frequently to the fire to warm themselves; and to physicians to say, how much healthier thick-built towns and cities will be, now half suffocated with sulphury smoke, when so much less of that smoke shall be made, and the air breathed by the inhabitants be consequently so much purer."

"[T]he builder of chimneys has been left to grope his way in the dark without assistant; and in almost every instance his attempts to improve upon the practice of his predecessors, have been unsuccessful; so that the inhabitants of these countries, with justice, complain that the inconveniencies felt in new houses from this cause, usually are more than sufficient to counterbalance all the elegancies that modern refinement has introduced into the dwellings..."

"In the same manner... when the air contiguous to a fire is heated... it is immediately expanded very much; and therefore instantly rises upwards, till it reaches the higher regions of the atmosphere, or is cooled by gradually mixing with the denser air it meets with in its ascent:—and as its place contiguous to the fire is immediately occupied by the cold dense air around it, which rushes from every side towards that point, it is heated and rarefied in its turn, and ascends in the same manner, carrying the smoke that rises from the burning body along with it."

"[W]here the throat of the Chimney has an end... where it enters into the lower part of the open canal of the Chimney, there the three walls which form the two covings and the back of the Fire-place all end abruptly. ...[T]hey should end in this manner for were they to be sloped outward and raised in such a manner as to swell out the upper extremity of the throat of the Chimney in the form of a trumpet, and increase it by degrees to the size of the canal of the Chimney, this manner of uniting the lower extremity of the canal of the Chimney with the throat would tend to assist the winds which may attempt to blow down the Chimney, in forcing their way through the throat, and throwing the smoke backward into the room; but when the throat of the Chimney ends abruptly, and the ends of the new walls form a flat horizontal surface, it will be much more difficult for any wind from above, to find, and force its way, through the narrow passage of the throat..."

"6. Charcoal fires in pots are used chiefly in the shops of handicraftsmen. They warm a room (that is kept close, and has no chimney to carry off the warmed air,) very speedily and uniformly; but, there being no draft to change the air, the sulphurous fumes from the coals (be they ever so well kindled before they are brought in, there will be some,) mix with it, render it disagreeable, hurtful to some constitutions, and some times, when the door is long kept shut, produce fatal consequences."

"[T]he flame and smoke will ascend and strike the top... 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."

"4. The Holland iron stove, which has a flue proceeding from the top, and a small iron door opening into the room, comes next to be considered. Its conveniences are, that it makes a room all over warm; for, the chimney being wholly closed except the flue of the stove, very little air is required to supply that, and therefore not much rushes in at crevices, or at the door when it is opened. Little fuel serves, the heat being almost all saved; for it rays out almost equally from the four sides, the bottom, and the top, into the room , and presently warms the air around it, which, being rarefied, rises to the ceiling, and its place is supplied by the lower air of the room, which flows gradually towards the stove, and is there warmed, and rises in its turn, so that there is a continual circulation till all the air in the room is warmed. The air, too, is gradually changed, by the stove-door's being in the room, through which part of it is continually passing, and that makes these stoves wholesomer, or at least pleasanter than the German stoves... But... There is no sight of the fire... When the room is warm, people, not seeing the fire, are apt to forget supplying it with fuel... The change of air is not carried on quite quick enough; so that, if any smoke or ill smell happens in the room, it is a long time before it is discharged. For these reasons the Holland stove has not obtained much among the English (who love the sight of the fire) unless in some workshops..."

"3. To remedy this, the Sieur Gauger gives, in his book, entitled La Méchanique de Feu, published in 1709, seven different constructions of the third sort of chimneys mentioned above, in which there are hollow cavities made by iron plates in the back, jambs, and hearths, through which plates the heat passing warms the air in those cavities, which is continually coming into the room fresh and warm. The invention was very ingenious, and had many conveniences; the room was warmed in all parts, by the air flowing into it through the heated cavities; cold air was prevented rushing through the crevices, the funnel being sufficiently supplied by those cavities; much less fuel would serve, &c. But the first expense, which was very great, the intricacy of the design, and the difficulty of the execution, especially in old chimneys, discouraged the propagation of the invention; so that there are, I suppose, very few such chimneys now in use. The upright heat, too, was almost all lost in these, as in the common chimneys."

"5. The German stove is like a box, one side wanting. It is composed of five iron plates, screwed together, and fixed so as that you may put the fuel into it from another room, or from the outside of the house. It is a kind of oven reversed, its mouth being without, and body within, the room that is to be warmed by it. This invention certainly warms a room very speedily and thoroughly with little fuel; no quantity of cold air comes in at any crevice, because there is no discharge of air which it might supply, there being no passage into the stove from the room. ...Its inconveniences are, that people have not even so much sight or use of the fire as in the Holland stoves, and are, moreover, obliged to breathe the same unchanged air continually, mixed with the breath and perspiration from one another's bodies, which is very disagreeable to those who have not been accustomed to it."

"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 fire place hindering it from going up the chimney, it is forced out into the room, rises by the mantel-piece to the ceiling, and spreads all over the top of the room, whence being crowded 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."

"To avoid the several inconveniences, and at the same time retain all the advantages of other fire-places, was contrived the PENNSYLVANIAN FIRE-PLACE, now to be described."

"It is to be observed, that the entering air will not be warm at first lighting the fire, but heats gradually as the fire increases."

"The air that enters the room through the air-box is fresh, though warm; and, computing the swiftness of its motion with the areas of the holes, it is found that near ten barrels of fresh air are hourly introduced by the air-box; and by this means the air in the room is continually changed, and kept at the same time sweet and warm."

"Its advantages above the common fire-places are, 1. That your whole room is equally warmed, so that people need not crowd so close round the fire, but may sit near the window, and have the benefit of the light for reading, writing, needlework, &c. They may sit with comfort in any part of the room... 2. If you sit near the fire, you have not that cold draft of uncomfortable air nipping your back and heels, as when before common fires, by which many catch cold, being scorched before, and... froze behind. 3. If you sit against a crevice, there is not that sharp draft of cold air playing on you, as in rooms where there are fires in the common way; by which many catch cold, whence proceed coughs, catarrhs, tooth-aches, fevers, pleurisies, and many other diseases. 4. In case of sickness, they make most excellent nursing-rooms; as they constantly supply a sufficiency of fresh air, so warmed at the same time as to be no way inconvenient or dangerous. A small one does well in a chamber; and, the chimneys being fitted for it, it may be removed from one room to another, as occasion requires, and fixed in half an hour. The equal temper, too, and warmth of the air of the room, is thought to be particularly advantageous in some distempers... 5. In common chimneys, the strongest heat from the fire, which is upwards, goes directly up the chimney, and is lost; and there is such a strong draft into the chimney, that not only the upright heat, but also the back, sides, and downward heats are carried up the chimney by that draft of air; and the warmth given before the fire, by the rays that strike out towards the room, is continually driven back, crowded into the chimney, and carried up by the same draft of air. But here the upright heat strikes and heats the top plate, which warms the air above it, and that comes into the room. The heat likewise, which the fire communicates to the sides, back, bottom, and air-box, is all brought into the room; for you will find a constant current of warm air coming out of the chimney corner into the room. Hold a candle just under the mantel-piece, or breast of your chimney, and you will see the flame bent outwards; by laying a piece of smoking paper on the hearth, on either side, you may see how the current of air moves, and where it tends, for it will turn and carry the smoke with it. 6. Thus, as very little of the heat is lost, when this fire-place is used, much less wood will serve you, which is a considerable advantage where wood is dear. 7. When you burn candles near this fire-place, you will find that the flame burns quite upright, and does not blare and run the tallow down, by drawing towards the chimney, as against common fires. 8. This fire-place cures most smoky chimneys, and thereby preserves both the eyes and furniture. 9. It prevents the fouling of chimneys; much of the lint and dust that contributes to foul a chimney being, by the low arch, obliged to pass through the flame, where it is consumed. Then, less wood being burnt, there is less smoke made. Again, the shutter, or trap-bellows, soon blowing the wood into a flame, the same wood does not yield so much smoke as if burnt in a common chimney; for, as soon as flame begins, smoke in proportion ceases. 10. And, if a chimney should be foul, it is much less likely to take fire. If it should take fire, it is easily stifled and extinguished. 11. A fire may be very speedily made in this fire-place by the help of the shutter, or trap-bellows... 12. A fire may be soon extinguished by closing it with the shutter before, and turning the register behind, which will stifle it, and the brands will remain ready to rekindle. 13. The room being once warm, the warmth may be retained in it all night. 14. And lastly, the fire is so secured at night, that not one spark can fly out into the room to do damage."

"With all these conveniences, you do not lose the pleasing sight nor use of the fire, as in the Dutch stoves, but may boil the tea-kettle, warm the flat irons, heat heaters, keep warm a dish of victuals by setting it on the top, &c."

"The earth is every where surrounded with a great body of air, that is called the atmosphere. This air is a thin elastic fluid, possessing some qualities peculiar to itself, but subjected in general to the same physical laws with other fluids; and of consequence it hath a constant tendency to preserve an exact equilibrium in all its parts; so that if at any time the weight of it at one place is diminished, the heavier air rushes from all sides towards that point, till the equilibrium be again restored."

"[T]he causes which produce smoke in rooms... may be all reduced to one of the three following general classes: 1. A faulty construction of the tube, vent, or chimney itself; 2. To some fault in the other parts of the building, and a wrong position of the chimney with respect to these; or, 3. To an improper situation of the house with respect to external objects."

"Many are the causes that may tend to destroy this equilibrium of the atmosphere; but the only one that it imports our present discussion to explain the effects of, is ."

"When heat acts upon the air, it immediately makes it expand to a great degree, so as that the same quantity of it occupies a much larger space than formerly. Hence... where a fire is kindled, the air immediately contiguous to it will be heated, and of consequence rarefied, and made lighter..."

"[W]hen the grate is brought forward, there is a great vacancy left between it and the back of the chimney, so... air passes under the grate, and ascends behind it very little rarefied; so... there will be as much lost in this way as will be gained in the other: and as there is not enough of heated air... to make the vapour ascend with rapidity, they are often choaked with thick fuliginous vapours hanging in them, almost in equilibrio with the rest of the atmosphere, so that the least puff of wind beats them down the chimney, and pushes the smoke into the room; whereas, when it is far back, it is driven down upon the hearth, and rises upwards again when the gust is over, and a great deal of it is catched within the mantle as it rises, which in the other case would have been dispersed through the room."

"[N]o form of the funnel of the chimney has any share in its operation or effect respecting smoke, except its height. The longer the funnel if erect, the greater its force when filled with heated and rarefied air, to draw in below and drive up the smoke (if one may in compliance with custom use the expression draw), when in fact it is the superior weight of the surrounding atmosphere that presses to enter the funnel below, and so drives up... the smoke and warm air..."

"A chimney may not only be defective by having the mantle too high, or by being too wide from side to side, but also by being too deep between the fore-side and the back, as is often the case in very old houses. In this case, the distance between the fire and the mantle is so great, that much air passes up without being sufficiently rarefied... This fault may be sometimes cured, by bringing the grate a little forward, which, by making the fire act more powerfully upon the mantle, rarefies the air more in its passage."

"[H]igh [longer] chimneys... have a greater suction of air, and are less liable to vent ill, than low ones, and this is one principal reason why in the same house the chimneys in the garrets, and the higher stories, are more apt to vent ill, than those on the floor, where the chimneys are of necessity longer. A smoky chimney, therefore, may sometimes be cured, merely by raising it higher..."

"When this is the case the most effectual method... is, to bring the grate forward till the forepart of it is immediately under the inner edge of the mantle; then build up the vacancy at the back of it, the whole width of the fire-place from side to side, raising it perpendicularly till it is as high as the back of the grate, and then bending it forward towards the mantle, as... fig 4. When it is as high as the workman can reach, let it be suddenly turned backward again, sloping a little upward... then fit a sheet of milled iron to the inside of the mantle, making it slant a little upward toward the back... a small distance above the new... masonry, and extending within a few inches of the back wall... By this construction all the air that enters into the chimney is made to pass immediately above the fire, between it and the heated iron... as the back of the fire-place is bent a little forward above the grate... the heat is likewise reflected into the room with the greater force... [I]f the smoke is accidentally beat down the chimney by a sudden gust of wind, it will be catched by the sheet of Iron, and prevented from coming into the room."

"[Y]ou desire me to give you... my thoughts upon the Construction and Use of Chimneys... I embrace willingly this leisure... to comply... as it will not only fhew my regard to... a friend, but may... be of some utility to others; the doctrine of chimneys appearing not to be as yet generally well understood, and mistakes respecting them being attended with constant inconvenience, if not remedied; and with fruitless expence, if the true remedies are mistaken."

"Smoke being rarely seen but in company with heated air, and its upward motion being visible, though that of the rarefied air that drives it is not so, has naturally given rise to... error."

"[A]ir is a which has weight as well as others, though about eight hundred times lighter than water; that heat makes the particles of air recede from each other and take up more space, so that the same weight of air heated will have more bulk [volume] than equal weights of cold air which may surround it, and in that case must rise, being forced upwards by such colder and heavier air, which presses to get under it, and take its place."

"What is it then which makes a smoky chimney..? The causes of this effect which have fallen under my observation, amount to nine..."

"[M]any of the diseases proceeding from colds, as fevers, pleurisies, &c., fatal to very great numbers of people, may be ascribed to strong-drawing chimneys, whereby, in severe weather, a man is scorched before, while he is froze behind."