Abbildungen der Seite
PDF
EPUB

against the house with all imaginable ease. On table or box would not elevate the person high the top of the upper ladder on the outside, are enough; and still fewer, where the roof would two pulleys, over which chains are conducted to resist the force, even of a delicate female. the windlass for the purpose of carrying up a FIRE-GRATE. A grate or stove to produce box: two of these travel with the fire-escape, so the most perfect combustion of fuel in heating that in the event of one being filled with small buildings, must be furnished with apertures for valuables, it may be unhooked, and the other put the constant supply of oxygen, which is the eson, which will save time. The whole apparatus may sential food of fire. Hence the word “grate,' or be drawn by one horse or six men, and when ar- 'grating,' which is usually placed at the bottom rived at the scene of danger may be adjusted in of the fire-place. two minutes. If every parish would provide one The theory of the common fire-grate is so of these escapes, and keep it where it may be simple, that but little attention need be paid to brought out on the first alarm, there is no doubt the matter; and we had better, in the present arbut that it would tend materially to lessen the ticle, direct our attention to those useful varianumber of accidents which occur by fire in the tions from the ordinary arrangement best calcumetropolis.

lated to answer the purpose of the domestic ecoThe Society for the Encouragement of Arts nomist. have rewarded M. Bordier for the construction In 1785 Dr. Franklin published the descripof a bag fire-escape. It consists of a tube or tion of a grate which has the flame reversed; slide of coarse cloth, of any convenient length, that is, it passes downwards through the fuel. which may be carried to any required distance. The appearance of this stove is that of a vase of This tube, which is attached to a ladder of ropes, cast-iron, with its pedestal, and this is mounted is firmly fastened at one end to a light but strong upon the top or lid of an air-box, standing upon square frame, of the same dimensions as a the hearth of the fire-place, and built close in a middling sized window, to which the frame is niche in the stone-work: but the vase, being fixed. The other end of the tube is closed. In wholly detached from the back of the niche, has the middle of the upper cloth a longitudinal slit a very neat appearance. The top of the vase turns is made, sufficiently large to admit a man: this back upon a hinge, so as to open like a lid, to end is fastened to a solid place, a little elevated put in the fuel; and the opening is covered by above the ground, and distant from the face of a brass frame, which allows the air to enter. the wall about half the height of the window, to The bottom of the vase has in it an opening, of which the other extremity of the tube is attached. about two inches diameter, which leads through Persons, therefore, that enter, or are put into the the stem or foot of the vase into a hollow iron upper orifice of this bag, will slide down by their box, forming the pedestal: at the bottom of this own weight, and with an accelerated or retarded pedestal there is a grating in the lid or top of the motion, according to the manner in which the air-box, upon which the vase stands. The airapparatus is placed, or at the pleasure of the per- box is divided by four partitions, between which sons descending, who, by spreading their hands the smoke passes and re-passes horizontally in a and feet, can regulate their own movements. waving direction, until it escapes into the chimThe lower end of the tube being fixed to a point, ney. Thus the smoke and flame, immediately a little raised from the ground, no part of the after it has descended through the grate in the tube can touch the ground, consequently the top of the air-box, passes backwards towards the persons descending run no risk of being hurt by chimney between the two middle partitions; but Coming suddenly upon the ground or pavement. as it cannot enter into the chimney at that part,

Feather beds have, within the last few years, it turns round the ends of those partitions, and been recommended as a means of escape from returns in two currents towards the front of the fire, when others fail or cannot be obtained. The box; then returns again round the end of the plan suggested is, that a few strong men should other partitions, and goes back into the chimney hold one in their hands extended, and that the which is behind, or rather at the sides of the persons in danger should throw themselves on to niche in which the vase stands. The front plate it

, endeavouring to leap outward as far as pos- of the air-box is made to slide in a groove, in sible, from the front or wall of the house on fire. two pieces, which meet together in the front like The neighbours would furnish the beds, and, that folding-doors; and these pieces being slided they may instantly be ready, an ingenious asso- back, expose the spaces between the partitions, ciation of the word feather-beds is proposed with which, as before mentioned, act as winding flues the cry of fire

, usual at those times, fire-feather- for the smoke to circulate in, and give out its beds. The humanity of the suggestion, its easy heat through the metal of the air-box. In the application, and the importance of its successful space between the two middle partitions, and results, entitle it to universal diffusion.

into which the smoke first descends, a drawer is It may also be suggested here, that one means fitted to receive the ashes or cinders, which may of escaping when the lower part of a house is on fall through the grate in the top of the air-box": fore, is through the roof. This in many cases and it can be readily withdrawn, to clear it out. could be very easily effected. Retiring to the There is likewise a small grate at the lower part upper chamber and shutting the door, to prevent of the vase, upon which the fuel contained in the a current of air, an aperture may be made in a vase will rest. When this fuel is lighted, the few minutes through the lath and plaster of the flame and smoke will draw downward, and, deceiling, and the tiled or slated roof, by a poker, scending through the grate, will pass through the the back of a chair, or a tester rod; and a way hole in the bottom of the vase into the hollow of exit procared. There are few cases where a pedestal, and through the grate in the top of the

air-box: it then passes horizontally in the space the fire is wanted, though some hours afterwards, between the two middle partitions of the air-box, by taking off the tin-plate, and admitting the air, and proceeds in the same direction towards the the fire will soon be recovered. back of the chimney; there dividing, one part

The effect of this machine, well managed, is of it turns to the right, and passes round the far- to burn not only the coals, but all the smoke ther end of the middle partition; then coming from them; so that while the fire is burning, if forwards, it turns round the near end of the out the top of the chimney is observed, no smoke side partition; then, moving backwards, it arrives will be seen issuing, nor any thing but clear at the opening into the bottom of one of the up warm air, which, as usual, makes the bodies seen right corner funnels behind the niche, through through it appear waving. But it must not be which it ascends into the chimney, thus heating imagined from this, that it can be a cure for bad that half of the box and that side of the niche. or smoky chimneys, much less that, as it burns The other part of the divided flame passes to the the smoke, it may be used in a room that has no left, reund the far end of the middle partition, chimney. It is only by the help of a good round the near end of the ontside partition, and chimney, and the higher the better, that it proso into and up the other corner funnel; thus duces its effect at all; and, though a flue of plate heating the other half of the box, and the other iron sufficiently high might be raised in a very side of the niche. The vase itself

, and the box, lofty room, the management to prevent all disawill also be very hot; and the air surrounding greeable vapor would be too nice for common them being heated, and rising as it cannot get practice, and small errors would have unpleasing into the chimney, it spreads in the room ; colder consequences. It is certain that clear iron yields air succeeding, is warmed in its turn, and rises no offensive smell, when heated : whatever smell and spreads, till by the continual circulation of that kind is perceived when there are iron the whole is warmed.

stoves, proceeds, therefore, from some foulness If there is occasion to make the fire when the burning or fuming on their surface; they should chimney does not draw, it must not be begun in therefore, never be spit upon, or greased, nor the vase, but in one or more of the passages of should any dust be suffered to lie npon them. the lower air-box; first withdrawing the sliding But, as the greatest care will not always prevent front of the air-box, and covering the mouth of these things, it is well once a week to wash the the vase. After the chimney has drawn some stove with soap-lees and a brush, rinsing it with time with the fire thus low, and begins to be a clean water. little warm, those passages may be closed, and The advantages of this reversed flame in stoves, another fire kindled in the hollow pedestal, leav- are very considerable. The chimney does not ing its sliding shutter a little open; and when it grow foul, nor erer need sweeping; for as de is found that the chimney, being warmed, draws smoke enters it, so no soot can form in it. forcihly, that passage may be shut, and the vase The air heated over common fires instantly opened, to make the fire there, as above directed. quits the room, and goes up the chimney with The chimney, well warmed by the first day's fire, the smoke; hut, in the stove, it is obliged to de. will continue to draw constantly all the winter, scend in flame, and pass through the long windif the fire is made daily.

ing horizontal passages, communicating its heat In the management of this stove, there are to a body of iron-plate, which, having thus time certain precautions to be observed, at first with to receive the heat, communicates the same to attention, till they become habitual. To avoid the air of the room, and thereby warms it to a the inconvenience of smoke the grate must be greater degree. cleared before beginning to light a fire. If it is The whole of the fuel is consumed by being found clogged with cinders and ashes, the grate turned into flame, and the benefit of its heat is must be lifted up with the tongs, to let them fall obtained ; whereas, in common chimneys, a great upon the grate in the top of the air-box: the part goes away in smoke, which may be seen as ashes will go through it into the drawer, and the it rises, but it affords no rays of warmth. Some cinders may be raked off through a sliding door idea may be formed of the quantity of fuel thus in the pedestal, and returned into the vase, when wasted in smoke, by reflecting on the mass of they are to be burnt. Care must be taken that soot that a few weeks firing will lodge against all the sliding-plates are in their places, and the sides of the chimney; and yet this is formed closely shut, that no air may enter the stove but only of those particles of the column of smoke through the round opening at the top of the which happen to touch the sides in its ascent. vase; and, to avoid the inconvenience of dust How much more must have passed off in the air? from the ashes, let the ash-drawer be taken out And we know that this soot is still fuel, for it will of the room to be emptied. The passages should burn and flame as such; and, when hard caked be cleaned or raked out, when the draught of the together, is indeed very like and almost as solid air is strong inwards; and the ashes must be put as the coal from which it proceeds. The decarefully into the ash-box, whilst it remains in struction of fuel goes on nearly in the same its place.

quantity in smoke as in flame, hut there is no If it is required to prevent the fire burning in comparison in the difference of heat given. the absence of the proprietor, it may be done by When fresh coals are first put on a fire, a consiremoving the brass frame from the top of the derable body of smoke arises. This smoke is, vase, and covering the passage or opening into for a long time, too cold to take flame; but if a the top of the vase with a round tin-plate, which burning candle is plunged into it, the candle, inwill prevent the entry of more air than barely stead of inflaming the smoke, will instantly be sufficient to keep a few of the coals alive. When itself extinguished. Smoke must have a certain

degree of heat to be inflammable. As soon as it diminishing, so that we are often obliged to rehas acquired that degree, the approach of a can move it by the snuffers, or bend it out of the dle will inflame the whole body, and the differ- flame into the air, where it presently consumes ence of the heat which it gives will be very sen to ashes. He then supposed, that to consume a sible. A still easier experiment may be made body of fire, passing air was necessary to receive with a candle itself. Hold your hand near the and carry off the separated particles of the body: side of its flame, and observe the heat it gives: and that the air passing in the flame of the stove, then blow it out, the hand remaining in the same and in the flame of a candle, being already satuplace, and observe what heat may be given by rated with such particles, could not receive more, the smoke that rises from the still burning snuff; and therefore left the coal undiminished as long you will find it very little : and yet the smoke as the outward air was prevented from coming has in it the substance of so much fame, and to it by the surrounding flame, which kept in a will instantly produce it, if you hold another situation somewhat like that of charcoal in a well candle above it so as to kindle it. Now the luted crucible, which, though long kept in a smoke from the fresh coals, laid on this stove, strong fire, comes out unconsumed. instead of ascending ard leaving the fire, while Mr. Craigie has a patent fire-grate of a very too cold to burn, being obliged to descend peculiar construction. It consists of a foundathrough the burning coals, receives among them tion or basis of about four feet in length by about that degree of heat which converts it into flame: two feet eight inches in breadth, and about and the heat of that flame is communicated to the twenty inches in height; at ne end in the front air of the room, as above explained.

is to be placed the chimney grate, eighteen inches The flame from the fresh coals laid on in this wide and six deep. On the foundation in the stove, descending through the coals already ig- centre, at nineteen inches distant from each other, nited, preserves them long from consuming, and are to be raised two sides in stone or brick, the continues them in the state of red coals, as long whole length thereof, about eight inches in height; as the flame continues that surrounds them, by on these sides is to be placed a pan of cast iron, which means the fires made in this stove are of of size to cover the whole, with rims to rest on much longer duration than in any other, and fewer the sides, but leaving a small space vacant, say coals are therefore necessary for the day. This about half an inch from each side below; the is a very material advantage indeed. That flame depth of the pan may be about five or six inches, should be a kind of pickle to preserve burning and will be raised above the basis, so as to leave coals from consuming, may seem a paradox to an aperture throughout of about an inch and a many, and very unlikely to be true, as the doctor half; at the end of the furnace, opposite to the firetells us it appeared to himself the first time he grate, the aperture will terminate in a flue of observed the fact; he therefore relates the cir- brick or iron to convey the smoke into the chimcumstances, and mentions an easy experiment, ney of the house, which flue should be furnished by which his reader may be in possession of with a register or damper. every thing necessary to the understanding of it. A plate projecting from the lower end of the In the first trial he made of this kind of stove, pan will form the top of the fire-place, of eighwhich was constructed of thin iron plate, he had, teen inches by six or eight; the sides will be instead of the vase, a kind of inverted pyramid, . formed of fire-bricks; the back of the fire-brick like a mill-hopper; and fearing at first that the will ascend towards the top in a sloping direction small grate contained in it might be clogged by under the pan. A frame of iron will be placed cinders, and the passage of the fame sometimes to receive the door or front, which will be in obstructed, he ordered a little door near the the clear about eighteen inches in width by about grate, by means of which he could occasionally sixteen inches in depth, that is to say, to cover clear it; though after the stove was made, and the ash-pit four inches, and about twelve inches before he had tried it, he began to think this above the grate for the fire-place, in front of precaution superfluons, from an imagination that which there should be an inner grate of about the flame, being contracted in the narrow part five or six inches high ; this door must have in where the grate was placed, would be more the lower part of it, about an inch and a half powerful in consuming what it should there meet from the bottom, a small door of about three with, and that any cinders between or near the inches wide by two in depth, to furnish air bars would be presently destroyed and the pas- through the ash-pit. When wood is used for sage opened. After the stove was fixed, and in fuel, the depth of the fire-place may be twelve action, he had a pleasure now and then in open- inches instead of six. The iron pan being filled ing that door a little, to see through the crevice with dry sand, will form a sand bath, with heat how the flame descended among the red coals, sufficient according to the depth to which the and, observing once a single coal lodged on the vessel is placed in it for all ordinary purposes, bars in the middle of the focus, he observed by and being once heated will retain the heat for a a watch in what time it would be consumed : he considerable time, especially if the doors are looked at it long without perceiving it to be at kept close shut; the plate or front will serve for all diminished, which surprised bim greatly. At broiling or frying. Roasting may be performed length it occurred to him that he had seen the same to perfection before the door in front even with thing a thousand times, in the conversion of the the doors shut; an oven for baking may be fixed -ed coal formed in the snuff of a burning candle, at the flue. Convenience will be found in having which, while enveloped in flame, and thereby the meat, &c., to be roasted suspended from a prevented from the contact of the passing air, is moveable fire-screen. long continued, and angments instead of The great numbers of manufactories destroyed

by are in consequence of the large quantities of four or five feet, by merely putting a few shavloose shavings in carpenters' and joiners' shops, ings into the cylinder frequently, in place of induced Mr. Davis to contrive a fire-grate for a filling it, they become converted into flame, safe and economical mode of burning shavings; which is carried the whole length of the iron the object of which is to employ these useful flue, heating it uniformly throughout. No soot combustible materials as fuel, instead of coal, lodges in the flue, but merely light ashes, which by such a construction of the grate, that they can be easily cleared out from time to time, as will not burn too fast, as they do in an open fire, may be necessary. luaking an intense heat, but only of a momentary The Swedish or Russian mode of warming duration. This is effected by putting the shavings buildings is thus described by M. Guyton in the into a sheet iron cylinder, closed at top, which Annales de Chimie. The construction of the is fitted into the top of a grate, very similar to apparatus which is there recommended may be those used for burning coals; and the flame pro- improved, to adapt it to our use in England, duced by the shavings passes through flues con where pit coal is used; but the following prinducted in the usual manner; the air which sup- ciples, which the author lays down, are very useports the combustion being supplied through the ful as guides in making all kinds of stoves for bars of the grate.

warming apartments. 1. Heat is produced only The fire-grate is twelve inches wide, and one in proportion to the volume of air consumed by foot three inches high; it is of cast iron, and the fuel. 2. The quantity of heat produced is lined with fire tiles, having a door with an ash- greatest (the quantity and quality of the fuel pit beneath, in the usual manner; the sheet iron being the same) when the combustion is most pipe conveys the smoke and Aame from the fire- complete. 3. The combustion is the more complace into a brick flue, and this leads into the plete, in proportion as the fuliginous part is chimney; there is an iron door opening into the longer retained in channels where it may undergo chimney for the sweeping machine, or boy, to a second combustion. 4. The only useful heat pass through to sweep the chimney; the sheet is that sent out into, and retained in, the

space iron cylinder, in which the shavings are put to intended to be heated. The temperature of that be consumed, is about nine inches in diameter, space will be higher in proportion as the curand sixteen inches high : it is placed over a cir- rent, which must be renewed from without to cular aperture in the top of the fire-grate, and support the combustion, is less enabled to take has a neck to prevent the sparks of the shavings up in its passage the heat produced. from flying out into the workshop. The cylinder Hence the following inferences evidently arise : is covered at top with a lid, having also a neck, -1. The fire-place ought to be insulated from which is removed at pleasure by a handle, to all bodies that are rapid conductors of heat. All put in a supply of shavings; this fits very close, the heat that goes out of the apartment is absoand, as no air can pass by it, a sufficient draught lutely lost, unless intentionally directed into to burn the shavings, but slowly, is afforded by another apartment. 2. Heat being produced the air passing through the bars of the grate, only by combustion, and combustion being suswhich is impeded by the ashes that may be tained only by a current of air, the current should therein; but this flame may be increased to a be brought in by channels, where the needful rapid combustion, when necessary, by opening rapidity may be preserved without being too disthe door of the stove; the flame passes along tant from the space to be warmed, so that the the flues, and gives out an equable heat to the heat it there deposits may be gradually accumu

Iron bearers are fixed across the fue, lated in the whole of the insulated surface, in which may be used to support any work which order afterwards to flow out of it slowly, accordrequires drying, or for any other purpose of this ing to the laws of the equilibrium of that Auid. 3. kind. The supply of this stove with fuel from The wood being so far consumed as to give no more shavings is attended with so little trouble, and smoke, it is advantageous to close the mouth of is such an advantage to the workmen, that they these channels, in order to retain there the heat will always prefer burning the shavings to coals; that would otherwise be carried off through the so much so, that where ten men are at work, upper flue, by the continuance of a current of fresh there is a difficulty to collect shavings sufficient air, necessarily of a low temperature. 4. Lastly, it even to light the fire the next morning. By this follows from these maxims, that, all things being means the danger of fire, which has been fatal equal, a higher temperature will be obtained, and to so many manufactories, is greatly removed; supported during a much longer time, by forming the loose shavings being consumed as soon as in the internal parts of the stove, or under the they are made, and that in lieu of more expensive hearth of a chimney, and in their vicinity, tubes fuel; and so slowly are the shavings consumed, in which the air that comes from without may that the iron cylinder will hold enough, when be warmed before it enters the apartment, to completely filled, to supply the fire for upwards serve the purpose of combustion, or replace that of half an hour. To guard the workshops still which has been consumed. These have been more effectually from danger, the stove and its called bouches de chaleur (mouths or apertures iron flue is supported upon a mass of brick-work, of heat), because, instead of contemplating their which prevents any sparks from falling on the principal use and intention, it is commonly floor; and the sides of the brick-work afford imagined that they are only made in order to very convenient shelves on which to lay any give, by their issues, a more rapid current to the wood-work that requires heating or drying ; and heat produced. Nor is this idea absolutely devoid when a greater heat is required to extend to a of foundation, since the air that issues from them considerable length horizontally, as, for instance, has only changed its temperature, by carrying

room.

ot a portion of the heat that would have re Fire, Greek, a kind of factitious fire, called mained in the interior. Those, however, who by the Greeks, who were the inventors and prinwould proscribe them, as opposing the most im- cipal users of it, the maritime fire; and which portant object, which is the retaining of the heat burns with greater violence in water than out as long as possible, do not consider that they of it. It is said to have been composed of may be closed, and all communication with the naphtha, bitumen, pitch, sulphur, and gum, and external air cut off by a simple slide, and, there was only to be extinguished by vinegar mixed fore, it is easy to derive from them every possible with sand and urine. Leonard da Vinci deadvantage without any inconvenience. And we scribes the composition as formed by mixing may add that in small apartments, or such as over the fire, the charcoal of willow, nitre, are accurately closed, they are often indispensably. brandy, resin, sulphur, pitch, and camphor. A requisite, if we would avoid being exposed to woollen cord is then plunged in the mixture, and currents of cold air. Dr. Franklin very justly made into balls, which, when set on fire, are quotes a Chinese proverb to this effect: Shun thrown into the enemy's vessels. This fire was a current of air from a narrow passage as you employed principally in the wars of the Greeks would the point of an arrow.'

with their Saracen neighbours; and the Eastern The Swedish or Russian stoves, which have Romans retained the secret for above 400 years; chambers for the reception of the flame and and even at the end of the eleventh century, the smoke, are little known in this country: but Pisans, to whom every science and art were famithose which are in common use in the halls and liar, suffered the effects, without understanding vestibules of our great houses are French stoves. the composition of the Greek fire. It was at They differ from the others in having a very great length either discovered or stolen by the Mahomlength of small flues or winding passages, through medans, and in the holy wars of Syria and Egypt wbich the smoke passes, and communicates its they retorted the invention on the heads of the heat to the air, which circulates in similar pas- Christians. sages, until it becomes warmed, and makes its It might be used with equal effect by sea or exit through the mouths into the apartment. land, in battles or in sieges. It was either This method is not so simple as the small cham- poured from the ramparts in large boilers, or bers or apartments of the Russian stoves, nor launched in red hot balls of stone and iron, or is it so good in the long run; because the pas- darted in arrows and javelins, twisted round sages are very liable to become clogged with with flax which had deeply imbibed the inflamsoot; and, even before they are so clogged as to mable oil : sometimes it was deposited in fireintercept the passage of the smoke, the trans- ships, or most commonly blown through long mission of the heat is much impaired, because tubes of copper, planted on the prow of a galley. the interior surfaces of the flues, becoming coated The modern discoveries respecting combustion with soot, do not conduct the heat so rapidly, have disclosed the whole secret of compositions and, in consequence, a great part will still pass which burn without access to the atmosphere, out into the chimney. Also, these flues with by means of oxygen afforded from nitre. small passages require a stronger draught in the FIRE-Lock, in military affairs, the arms of chimney to make the air pass through the pas- a foot soldier, so called because it produces fire sages, than when chambers are used.

of itself by flint and steel, in contradistinction The Holland iron stove, which has a flue pro- from a match-lock, which requires a lighted ceeding from the top, the fire-place and ash-pit match. Firelocks were formerly three feet being closed by small iron doors opening into ight inches in the barrel, and weighed fourteen the room, comes next to be considered. It is pounds, at present the length of the barrel is frequently made of iron plate, and is most com- from three feet three inches to three feet six monly called a German stove. Its conveniences inches, and the weight of the piece only twelve are, that it makes a room warm all over, for the pounds. They carry a leaden bullet, of which chimney being wholly closed, except the flue of twenty-nine make two pounds, its diameter is the stove, very little air is required to supply •550 of an inch, and that of the barrel one-fifthat, and therefore not much rushes in at crevices, tieth part of the shot. See MUSKET. or at the door when it is opened. Little fuel FIRE-Pots, in the military art, small earthen serves, the heat being nearly all saved ; for it pots, into which is put a charged grenade, and radiates almost equally from the four sides, and over that powder enough to cover the grenade; the bottom and top, into the room, and presently the pot is then covered with a piece of parchwarms the air around it, which, being rarefied, ment, and two pieces of lighted match placed rises to the ceiling, and its place is supplied by across; this being thrown by a handle of matches the lower air of the room, wbich flows gradually where it is designed, it breaks and fires the powtowards the stove, and is there warmed and rises der, and burns all that is near it, and likewise in its turn, so that there is a continual circula- fires the powder in the grenade, which ought to tion, till all the air in the room is warmed. The have no fuse, that its operations may be the air, too, is gradually changed by the stove-doors quicker. being in the room, through which part of it is FIRE-REEDS, reeds used in fire-ships. They continually passing, and that makes these stoves are made up in small bundles of about a foot in more wholesome, or at least more pleasant, than circumference, cut even at both ends, and tied the German stoves. But they have the inconve- together in two places. They are distinguished nience that there is no sight of the fire, which into two kinds, viz. the long and short; the foris, in itself, a pleasant thing, nor can any other mer of which are four feet

, and the latter two use be conveniently made of the fire but that of feet five inches in length. One part of them warming the room

are singly dipped, i. e. at one end : the rest are

« ZurückWeiter »