Mr. Forster of Walthamstow, has contrived a very ingenious fire-escape. It was originally suggested by Mr. Maseres, and an account of the invention was published in the Philosophical Magazine. It consists of a suspension-iron, which is formed like the ramhead commonly used for slinging goods from warehouses, with this difference, however, that the bottom hooks are turned up close to the upright part, to form two close rings or eyes: the length of this iron is about four inches and a half; the thickness of the iron out of which it is hammered is about half an inch. The rope is made of flax, and platted in a peculiar manner. It should be about three-eighths of an inch in diameter, and must be somewhat more than twice the height of the window from the ground. The regulator is an oblong piece of beech wood, six inches and a half in length, three inches and a quarter broad, and about seven-eighths of an inch thick: in this there are four holes pierced for the rope to pass through; one of these is open at the sides there is also a notch at the top of this piece of wood, and an oblong hole about seven-eighths of an inch from the bottom. The upper bolt is a stout leathern strap, about four feet three inches long and one and a half broad, with a buckle to it. The lower belt is a strap of the same sort as the other; but the end, after being put through the buckle, is sewed down: this is for the purpose of security, in case the tongue of the buckle should by accident break. The union strap, so called from its connecting the regulator to the other parts of the machine, is leathern, and is about a foot and a half long and an inch and a quarter broad it has, like the others, a buckle to it. It is stained black, which distinguishes it from the other leathern straps. The method of putting together all these parts of the machine is, first to pass one end of the rope through the holes in the regulator, then through the two lower rings of the suspension-iron: the upper belt is then to be passed through a doubling of the union strap; after which the rope is to be tied to that belt, and the knot secured by a string from slipping (which string is to pass through two small holes in the leather); and at a foot below the rope is to be tied to the lower belt in like manner. Next the union strap is to be put through the oblong hole in the regulator, and buckled; by which the upper belt and the regulator will be connected. The other end of the rope may be kept wound on a wooden roller, to prevent it from getting entangled. Persons who purchase these machines should have a very strong iron hook, with a spring catch, fixed to some secure part of the window-frame, or elsewhere; on this hook the suspension iron is to be hung by the upper ring, when any one wishes to descend from the window. The next operation is to step into the lower belt with both feet, and draw it up sufficiently high, so as to form a kind of swing to sit in; the part of the strap which is through the buckle is to be laid hold of with the left hand; and the buckle, with the right hand, is to be slipped to its proper place, according to the size of the person: the tongue is then to be put into one of the holes, as in buckling common straps. After this is done, the upper belt is to be somewhat

loosely buckled round the chest, and then the rope which is on the roller is to be thrown out of the window on the ground. Now, all being ready for descending, the person is to get out of the window, grasping tight, with one or with both hands, the rope at some convenient part, taking especial care not to meddle with the suspension iron until quite out of the window; after which the rope below the regulator is to be laid hold of with the right hand, and to be let to run through the holes as fast as there may be occasion; for which purpose, if necessary, it may be easily slipped out of the open hole; it will then have the check of only three holes: if the motion is wanted to be retarded, the rope is to be put into the notch at the upper part of the regulator. When one person has descended, and there is a necessity for a second immediately to follow, the union strap is to be unbuckled, when the regulator will be separated from the upper belt: the belts may then be very easily drawn up, having the friction of the suspension-iron only, and the person above is to put on the belts as the other did, and is to be let down gradually, partly by the one below, and partly by managing the rope as the first did; in this case great care must be taken, as the check occasioned by the regulator is gone. It is not easy to lay down exact rules for what number of holes the rope must pass through, as this must vary according to the weight of the person, and other circumstances. It would be well, before the person gets out of the window, to examine, first, whether the suspension-iron is in the hook, this is absolutely necessary: then, that the three buckles are fast, the two knots tied, and that the rope is in the hole of the regulator which has the opening. Great care must be taken that there is not any impediment to the free running of the rope; for which the wall of the house must be examined, and any nails or hooks which may chance to be there removed; also iron scrapers, and every thing wherein the rope may be likely to catch.

Mr. Davis's fire-escape is calculated for the use of a parish; its principle consists in three ladders applied to each other by four clasp irons on the top of each of the two lowermost, which are so contrived that each ladder may slide into the one beneath it; on the top of the lowermost ladder, two pulleys are fixed on the inside, over which two ropes pass. The ropes are made fast to the bottom of the middle one on each side in a proper direction with the pulleys on the top. The upper ladder is attached to the middle one in the same manner, and on the top it carries two horn-pieces, made of iron, and turned off at each end similar to two horns which are four feet wide; their ends are sharp, to pitch on each side of a window, and with their points hold the ladders steady. The three ladders when shut down are about fifteen feet in height. They are placed perpendicularly in the middle of a framed carriage of nine feet six inches long, and five feet six inches wide, mounted upon four wheels. On each side of the carriage a windlass is placed, and, by turning it, the ladders may be wound out from their standing height of fifteen feet to forty. Over this windlass is a screw turned by a winch, by turning which the ladders may be inclined

air-box: it then passes horizontally in the space between the two middle partitions of the air-box, and proceeds in the same direction towards the back of the chimney; there dividing, one part of it turns to the right, and passes round the farther end of the middle partition; then coming forwards, it turns round the near end of the outside partition; then, moving backwards, it arrives at the opening into the bottom of one of the upright corner funnels behind the niche, through which it ascends into the chimney, thus heating that half of the box and that side of the niche. The other part of the divided flame passes to the left, round the far end of the middle partition, round the near end of the outside partition, and so into and up the other corner funnel; thus heating the other half of the box, and the other side of the niche. The vase itself, and the box, will also be very hot; and the air surrounding them being heated, and rising as it cannot get into the chimney, it spreads in the room; colder air succeeding, is warmed in its turn, and rises and spreads, till by the continual circulation the whole is warmed.

If there is occasion to make the fire when the chimney does not draw, it must not be begun in the vase, but in one or more of the passages of the lower air-box; first withdrawing the sliding front of the air-box, and covering the mouth of the vase. After the chimney has drawn some time with the fire thus low, and begins to be a little warm, those passages may be closed, and another fire kindled in the hollow pedestal, leaving its sliding shutter a little open; and when it is found that the chimney, being warmed, draws forcibly, that passage may be shut, and the vase opened, to make the fire there, as above directed. The chimney, well warmed by the first day's fire, will continue to draw constantly all the winter, if the fire is made daily.

In the management of this stove, there are certain precautions to be observed, at first with attention, till they become habitual. To avoid the inconvenience of smoke the grate must be cleared before beginning to light a fire. If it is found clogged with cinders and ashes, the grate must be lifted up with the tongs, to let them fall upon the grate in the top of the air-box: the ashes will go through it into the drawer, and the cinders may be raked off through a sliding door in the pedestal, and returned into the vase, when they are to be burnt. Care must be taken that all the sliding-plates are in their places, and closely shut, that no air may enter the stove but through the round opening at the top of the vase; and, to avoid the inconvenience of dust from the ashes, let the ash-drawer be taken out of the room to be emptied. The passages should be cleaned or raked out, when the draught of the air is strong inwards; and the ashes must be put carefully into the ash-box, whilst it remains in its place.

If it is required to prevent the fire burning in the absence of the proprietor, it may be done by removing the brass frame from the top of the vase, and covering the passage or opening into the top of the vase with a round tin-plate, which will prevent the entry of more air than barely sufficient to keep a few of the coals alive. When

the fire is wanted, though some hours afterwards, by taking off the tin-plate, and admitting the air, the fire will soon be recovered.

The effect of this machine, well managed, is to burn not only the coals, but all the smoke from them; so that while the fire is burning, if the top of the chimney is observed, no smoke will be seen issuing, nor any thing but clear warm air, which, as usual, makes the bodies seen through it appear waving. But it must not be imagined from this, that it can be a cure for had or smoky chimneys, much less that, as it burns the smoke, it may be used in a room that has no chimney. It is only by the help of a good chimney, and the higher the better, that it produces its effect at all; and, though a flue of plate iron sufficiently high might be raised in a very lofty room, the management to prevent all disagreeable vapor would be too nice for common practice, and small errors would have unpleasing consequences. It is certain that clear iron yields no offensive smell, when heated: whatever smell of that kind is perceived when there are iron stoves, proceeds, therefore, from some foulness burning or fuming on their surface; they should therefore, never be spit upon, or greased, nor should any dust be suffered to lie upon them. But, as the greatest care will not always prevent these things, it is well once a week to wash the stove with soap-lees and a brush, rinsing it with clean water.

The advantages of this reversed flame in stoves, are very considerable. The chimney does not grow foul, nor ever need sweeping; for as no smoke enters it, so no soot can form in it.

The air heated over common fires instantly quits the room, and goes up the chimney with the smoke; but, in the stove, it is obliged to descend in flame, and pass through the long winding horizontal passages, communicating its heat to a body of iron-plate, which, having thus time to receive the heat, communicates the same to the air of the room, and thereby warms it to a greater degree.

The whole of the fuel is consumed by being turned into flame, and the benefit of its heat is obtained; whereas, in common chimneys, a great part goes away in smoke, which may be seen as it rises, but it affords no rays of warmth. Some idea may be formed of the quantity of fuel thus wasted in smoke, by reflecting on the mass of soot that a few weeks firing will lodge against the sides of the chimney; and yet this is formed only of those particles of the column of smoke which happen to touch the sides in its ascent. How much more must have passed off in the air? And we know that this soot is still fuel, for it will burn and flame as such; and, when hard caked together, is indeed very like and almost as solid as the coal from which it proceeds. The destruction of fuel goes on nearly in the same quantity in smoke as in flame, but there is no comparison in the difference of heat given. When fresh coals are first put on a fire, a considerable body of smoke arises. This smoke is, for a long time, too cold to take flame; but if a burning candle is plunged into it, the candle, instead of inflaming the smoke, will instantly be itself extinguished. Smoke must have a certain

degree of heat to be inflammable. As soon as it has acquired that degree, the approach of a candle will inflame the whole body, and the difference of the heat which it gives will be very sensible. A still easier experiment may be made with a candle itself. Hold your hand near the side of its flame, and observe the heat it gives: then blow it out, the hand remaining in the same place, and observe what heat may be given by the smoke that rises from the still burning snuff; you will find it very little and yet the smoke has in it the substance of so much flame, and will instantly produce it, if you hold another candle above it so as to kindle it. Now the smoke from the fresh coals, laid on this stove, instead of ascending and leaving the fire, while too cold to burn, being obliged to descend through the burning coals, receives among them that degree of heat which converts it into flame: and the heat of that flame is communicated to the air of the room, as above explained.

The flame from the fresh coals laid on in this stove, descending through the coals already ignited, preserves them long from consuming, and continues them in the state of red coals, as long as the flame continues that surrounds them, by which means the fires made in this stove are of much longer duration than in any other, and fewer coals are therefore necessary for the day. This is a very material advantage indeed. That flame should be a kind of pickle to preserve burning coals from consuming, may seem a paradox to many, and very unlikely to be true, as the doctor tells us it appeared to himself the first time he observed the fact; he therefore relates the circumstances, and mentions an easy experiment, by which his reader may be in possession of every thing necessary to the understanding of it. In the first trial he made of this kind of stove, which was constructed of thin iron plate, he had, instead of the vase, a kind of inverted pyramid, like a mill-hopper; and fearing at first that the small grate contained in it might be clogged by cinders, and the passage of the flame sometimes obstructed, he ordered a little door near the grate, by means of which he could occasionally clear it; though after the stove was made, and before he had tried it, he began to think this precaution superfluous, from an imagination that the flame, being contracted in the narrow part where the grate was placed, would be more powerful in consuming what it should there meet with, and that any cinders between or near the bars would be presently destroyed and the passage opened. After the stove was fixed, and in action, he had a pleasure now and then in opening that door a little, to see through the crevice how the flame descended among the red coals, and, observing once a single coal lodged on the bars in the middle of the focus, he observed by a watch in what time it would be consumed: he looked at it long without perceiving it to be at all diminished, which surprised him greatly. At length it occurred to him that he had seen the same thing a thousand times, in the conversion of the red coal formed in the snuff of a burning candle, which, while enveloped in flame, and thereby prevented from the contact of the passing air, is long continued, and augments instead of

diminishing, so that we are often obliged to remove it by the snuffers, or bend it out of the flame into the air, where it presently consumes to ashes. He then supposed, that to consume a body of fire, passing air was necessary to receive and carry off the separated particles of the body: and that the air passing in the flame of the stove, and in the flame of a candle, being already saturated with such particles, could not receive more, and therefore left the coal undiminished as long as the outward air was prevented from coming to it by the surrounding flame, which kept in a situation somewhat like that of charcoal in a well luted crucible, which, though long kept in a strong fire, comes out unconsumed.

Mr. Craigie has a patent fire-grate of a very peculiar construction. It consists of a foundation or basis of about four feet in length by about two feet eight inches in breadth, and about twenty inches in height; at one end in the front is to be placed the chimney grate, eighteen inches wide and six deep. On the foundation in the centre, at nineteen inches distant from each other, are to be raised two sides in stone or brick, the whole length thereof, about eight inches in height; on these sides is to be placed a pan of cast iron, of size to cover the whole, with rims to rest on the sides, but leaving a small space vacant, say about half an inch from each side below; the depth of the pan may be about five or six inches, and will be raised above the basis, so as to leave an aperture throughout of about an inch and a half; at the end of the furnace, opposite to the firegrate, the aperture will terminate in a flue of brick or iron to convey the smoke into the chimney of the house, which flue should be furnished with a register or damper.

A plate projecting from the lower end of the pan will form the top of the fire-place, of eighteen inches by six or eight; the sides will be formed of fire-bricks; the back of the fire-brick will ascend towards the top in a sloping direction under the pan. A frame of iron will be placed to receive the door or front, which will be in the clear about eighteen inches in width by about sixteen inches in depth, that is to say, to cover the ash-pit four inches, and about twelve inches above the grate for the fire-place, in front of which there should be an inner grate of about five or six inches high; this door must have in the lower part of it, about an inch and a half from the bottom, a small door of about three inches wide by two in depth, to furnish air through the ash-pit. When wood is used for fuel, the depth of the fire-place may be twelve inches instead of six. The iron pan being filled with dry sand, will form a sand bath, with heat sufficient according to the depth to which the vessel is placed in it for all ordinary purposes, and being once heated will retain the heat for a considerable time, especially if the doors are kept close shut; the plate or front will serve for broiling or frying. Roasting may be performed to perfection before the door in front even with the doors shut; an oven for baking may be fixed at the flue. Convenience will be found in having the meat, &c., to be roasted suspended from a moveable fire-screen.

The great numbers of manufactories destroyed

by fire in consequence of the large quantities of loose shavings in carpenters' and joiners' shops, induced Mr. Davis to contrive a fire-grate for a safe and economical mode of burning shavings; the object of which is to employ these useful combustible materials as fuel, instead of coal, by such a construction of the grate, that they will not burn too fast, as they do in an open fire, making an intense heat, but only of a momentary duration. This is effected by putting the shavings into a sheet iron cylinder, closed at top, which is fitted into the top of a grate, very similar to those used for burning coals; and the flame produced by the shavings passes through flues conducted in the usual manner; the air which supports the combustion being supplied through the bars of the grate.

The fire-grate is twelve inches wide, and one foot three inches high; it is of cast iron, and lined with fire tiles, having a door with an ashpit beneath, in the usual manner; the sheet iron pipe conveys the smoke and flame from the fireplace into a brick flue, and this leads into the chimney; there is an iron door opening into the chimney for the sweeping machine, or boy, to pass through to sweep the chimney; the sheet iron cylinder, in which the shavings are put to be consumed, is about nine inches in diameter, and sixteen inches high: it is placed over a circular aperture in the top of the fire-grate, and has a neck to prevent the sparks of the shavings from flying out into the workshop. The cylinder is covered at top with a lid, having also a neck, which is removed at pleasure by a handle, to put in a supply of shavings; this fits very close, and, as no air can pass by it, a sufficient draught to burn the shavings, but slowly, is afforded by the air passing through the bars of the grate, which is impeded by the ashes that may be therein; but this flame may be increased to a rapid combustion, when necessary, by opening the door of the stove; the flame passes along the flues, and gives out an equable heat to the room. Iron bearers are fixed across the flue, which may be used to support any work which requires drying, or for any other purpose of this kind. The supply of this stove with fuel from shavings is attended with so little trouble, and is such an advantage to the workmen, that they will always prefer burning the shavings to coals; so much so, that where ten men are at work, there is a difficulty to collect shavings sufficient even to light the fire the next morning. By this means the danger of fire, which has been fatal to so many manufactories, is greatly removed; the loose shavings being consumed as soon as they are made, and that in lieu of more expensive fuel; and so slowly are the shavings consumed, that the iron cylinder will hold enough, when completely filled, to supply the fire for upwards of half an hour. To guard the workshops still more effectually from danger, the stove and its iron flue is supported upon a mass of brick-work, which prevents any sparks from falling on the floor; and the sides of the brick-work afford very convenient shelves on which to lay any wood-work that requires heating or drying; and when a greater heat is required to extend to a considerable length horizontally, as, for instance,

four or five feet, by merely putting a few shavings into the cylinder frequently, in place of filling it, they become converted into flame, which is carried the whole length of the iron flue, heating it uniformly throughout. No soot lodges in the flue, but merely light ashes, which can be easily cleared out from time to time, as may be necessary.

The Swedish or Russian mode of warming buildings is thus described by M. Guyton in the Annales de Chimie. The construction of the apparatus which is there recommended may be improved, to adapt it to our use in England, where pit coal is used; but the following principles, which the author lays down, are very useful as guides in making all kinds of stoves for warming apartments. 1. Heat is produced only in proportion to the volume of air consumed by the fuel. 2. The quantity of heat produced is greatest (the quantity and quality of the fuel being the same) when the combustion is most complete. 3. The combustion is the more complete, in proportion as the fuliginous part is longer retained in channels where it may undergo a second combustion. 4. The only useful heat is that sent out into, and retained in, the space intended to be heated. The temperature of that space will be higher in proportion as the current, which must be renewed from without to support the combustion, is less enabled to take up in its passage the heat produced.

Hence the following inferences evidently arise: -1. The fire-place ought to be insulated from all bodies that are rapid conductors of heat. All the heat that goes out of the apartment is absolutely lost, unless intentionally directed into another apartment. 2. Heat being produced only by combustion, and combustion being sustained only by a current of air, the current should be brought in by channels, where the needful rapidity may be preserved without being too distant from the space to be warmed, so that the heat it there deposits may be gradually accumulated in the whole of the insulated surface, in order afterwards to flow out of it slowly, according to the laws of the equilibrium of that fluid. 3. The wood being so far consumed as to give no more smoke, it is advantageous to close the mouth of these channels, in order to retain there the heat that would otherwise be carried off through the upper flue, by the continuance of a current of fresh air, necessarily of a low temperature. 4. Lastly, it follows from these maxims, that, all things being equal, a higher temperature will be obtained, and supported during a much longer time, by forming in the internal parts of the stove, or under the hearth of a chimney, and in their vicinity, tubes in which the air that comes from without may be warmed before it enters the apartment, to serve the purpose of combustion, or replace that which has been consumed. These have been called bouches de chaleur (mouths or apertures of heat), because, instead of contemplating their principal use and intention, it is commonly imagined that they are only made in order to give, by their issues, a more rapid current to the heat produced. Nor is this idea absolutely devoid of foundation, since the air that issues from them has only changed its temperature, by carrying