Abbildungen der Seite
PDF
EPUB

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 fame 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 beat 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 flame, 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 sinoke 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 one 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 enntinues 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 cany, 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 fue of observed the fact; he therefore relates the cir- brick or iron to convey the smoke into the chimcurastances, and mentions an easy experiment, ney of the house, which flue should be furnished ty 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 coders, and the passage of the flame 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 gate, 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 superfluous, 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

bere 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 rage 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 ad, 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 ail diminished, which surprised him 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

a coal formed in the snuff of a burning candle, at the fue. Convenience will be found in having which, while enveloped in flame, and thereby the meat, &c., to be roasted suspended froin a prevented from the contact of the passing air, is moveable fire-screen. can continued, and angments instead of The great numbers of manufactories destroyed by fire 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. waking 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 flame 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 pine 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 à 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 fines, and gives out an equable heat to the heat it there deposits may be gradually accumuroom. Tron bearers are fixed across the flue, Tated 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 fluid. 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 or halt an hour. To guard the workshops still which has been consumed. These have been inore effectually from dager, the stove and its called houches de chaleur (mouths or apertures Iron Aue 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 door ; and the sides of the brick-work afford imagined that they are only made in order to "ery convenient shelves on which to lay any give, by their issues, a more rapid current to the wood-work that requires heating or drving; and heat produced. Nor is this idea absolutely devoid when a greater heat is required to exten:) to a of foundation, since the air that issues from them sonsiderable length horizontally, as, for instance, has only changed its temperature, by carrying

22

off 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 fame 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 which the smoke passes, and communicates its they retorted the invention on the heads of the heal 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 inflamsot; 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 fues with by means of oxygen afforded from nitre. snall 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 eight 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 afe, 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 parchwarns 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, which 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 warning the roon.

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

dipped at both ends in a kettle of melted com- whence it extends obliquely to a sally port I, position. After being immersed about seven of cut through the ship's side. The decks and eight inches in this preparation, and then troughs are well covered with melted resin. drained, they are sprinkled over with pulverised At the time of the firing either of the leading sulphur upon a tanned hide.

troughs, the fame is immediately conveyed to Fire-Ships are generally old vessels filled the opposite side of the ship, whereby both with combustibles, fitted with grappling irons sides burn together. The spaces N, O, behind to hook, and set fire to, the enemies ships in the fire-room, represent the cabins of the lieutebattle, &c. As there is nothing particular in nant and master, one of which is on the starthe construction of this ship, except the appa- board, and the other on the larboard side. The ratus by which the fire is instantly conveyed captain's cabin, which is separated from these from one part to another, and thence to the by a bulk-head, is exhibited also by P. Four of enemy, it is sufficient to describe the fire-room, the eight fire-barrels are placed under the four where these combustibles are enclosed, together fire-trunks; and the other four between them, with the instruments necessary to grapple the two on each side of the fire scuttles, where they ship intended to be destroyed. The fire-room are sccurely cleated to the deck. The longest is built between decks, and limited on the after- fire-reeds are put into the fore and aft troughs, part by a bulkhead, L, behind the main nast, and tied down: the shortest reeds are laid in the from wbich it extends quite forward, as repre- troughs athwart, and tied down also. The firesented in the diagram at the foot of this article. bavins, dipped at one end, are tied fast to the The train enclosed in this apartment is contained troughs over the reeds, and the curtains are nailed in a variety of wooden troughs, D, G, which up to the beams, in equal quantities, on each intersect each other in different parts of the side of the fire-room. The remainder of the ship's length; being supported at proper dis- reeds are placed in a position nearly upright, at tances by cross pieces and stanchions. On each all the angles of every square in the fire-room, side of the ship are six or seven ports, H, about and there tied down. If any reeds are left, they eighteen inches broad and fifteen inches high; are to be put round the fire-barrels, and other and having their lids to open downward, con- vacant places, and there tied fast. trary to the usual method. Against every port The following instructions are given in the is placed an iron chamber, which, at the time regulations for a fire-ship of 150 tons burden: of firing the ship, blows out the port-lid, and The fire-barrels are to be two feet four inches opens a passage for the flame. The iron cham- high, and one foot six inches in diameter. Each bers are ten inches long and 3.5 in diameter. barrel must have four holes of about six inches They are breeched against a piece of wood fixed square, cut in its sides, with a square piece of ncross the ports, and let into another a little canvas nailed over each of thein. They are higher. When loaded they are almost filled then filled with the carcass-composition, and with corn-powder, and have a wooden tompion four plugs, of about one inch diameter and well driven into their muzzles. They are primed three inches long, and well greased, are thrust with a small piece of quick-match thrust through into the top, and then left to dry. When dry, their vents into the powder, with a part of it these plugs are taken out, and the holes filled hanging out. When the ports are blown open with fuse-composition, and quick-match at the by means of the iron chambers, the port-lids top, which goes from one hole to the other; either fall downward, or are carried away by the after this, the top is smeared over with mealed explosion. Immediately under the main and powder, mixed up with spirits of wine. When fore shrouds is fixed a wooden funnel M; whose dry again, a sheet or two of brown paper is laid lower end communicates with a fire-barrel, by over the top, and then one of the canvas covers, which the flame passing through the funnel is which is made secure by the upper hoop of the conducted to the shrouds. Between the fun- barrel. nels, whicn are likewise called fire-trunks, are The composition for dipping reeds, bavins, two scuttles, or small holes in the upper deck, and curtains, is serving also to let out the flames. Both funnels

Ibs. must be stopped with plugs, and have sail-cloth Resin .

120 or canvas nailed close over them, to prevent any Coarse sulphur

90 accident from above to the conibustibles laid Swedish pitch below. The ports, funnels, and scuttles, not Tallow only communicate the flames to the outside and

Mealed powder.

12 upper works of the ship and her rigging; but likewise open a passage for the inward air, con- In order to produce an additional external fined in the fire-room, which is thereby expanded fire, forty-four boxes are filled with the carcassso as to force impetuously through those out- composition, and distributed on the three masts lets, and prevent the blowing up of the decks, in the following manner :-One suspended from which must of necessity happen from such a each of the cat-heads and davits, on each side sudden and violent rarefaction of the air as will of the bow; eight slung across the bowsprit ; then be produced. On each side of the bulk four across each of the ont-riggers abaft; two head behind is cut a hole L, of sufficient size to from the grapplings of each of the lower yardadmit a trough of the samé dimensions as the arms; one from the dead-eyes on each side of others. A trough, L, I, whose foremost end the three round-tops; and one from the middle communicates with another trough within the of the inside of the main, fore, and mizen fire-room, is laid close to this opening, shrouds.

60

6

Besides the boxes, there are fire-barrels ar- fired, to the communication through the trough, ranged as follows :-Two half barrels on the laid with leaders of quick-match, that the fire forecastle; two abaft the main-deck, and four may be communicated on both sides at once. on the main-deck; two in each round-top, What quick-match is left must be placed so that placed against the masts; and four large fire- the fire may be communicated to all parts of the barrels, under fire-trunks, to convey fire to the room at once, especially about the ports and curtains on the shrouds. All these fire-barrels fire-barrels. The port-fire used for hiring the and boxes are to be fired by separate leaders of ship burns about twelve minutes; great care quick-match, or port-fire, in order that any part must be taken to have no powder on board when of the ship may be fired, to cover its approach the ship is fired. Sheer-hooks are fitted so as to hy the smoke; and the remaining part instanta- fasten on the yard-arms of the fire-ship, where neously upon quitting the ship. It has been they hook the enemy's rigging. The firefound, by experiment, that two men, with lighted grapplings are either fixed on the yard-arms, or port-fires, can set fire to the whole of the leaders thrown by hand, having a chain to confine the on the deck, bowsprit, cat-heads, out-riggers, &c., ships together, or fasten those instruments wherein less than a minute; therefore, the risk of ever necessary. Whenever the commanding trusting to one main leader to the whole may be officer of a fleet displays the signal to prepare avoided. The leaders are laid in painted canvas for action, the fire-ships fix their sheer-hooks, hose, made for the purpose.

and dispose their grapplings in readiness. The The proportion of combustible stores for a battle being begun, they proceed immediately to fire-ship of 150 tons, is as follows:

prime, and prepare their fire-works. When 8 Fire-barrels, filled with composition,

they are ready for grappling, they inform the 12 Iron chambers, to blow open the ports.

admiral thereof by a particular signal. To 250 Bavins, single-dipped.

avoid being disabled by the enemy's cannon 24 Port-fires.

during a general engagement, the fire-ships con3} Priming composition barrels.

tinue sufficiently distant from their line-of1 Quick-match ditto.

battle, either to windward or leeward. They 48 Dipped curtains.

cautiously shun the openings or intervals of the 150 Long reeds, single-dipped.

line, where they would be directly exposed to 75 Short reeds, single-dipped.

the enemy's fire, from which they are covered 75 Short reeds, double-dipped.

by lying on the opposite side of their own ships. 60 Hand grenades.

They are attentively to observe the signals of

the admiral or his seconds, in order to put their When ordered to prine, the captain is to take designs immediately into execution. Although up all his reeds, one after another, and strow a no ship of the line should be previously aplle composition at the bottom of all the troughs pointed to protect any fire-ship, except a few of under the reeds, and then tie them gently down the smallest particularly destined to this service, again; next to strow composition upon the yet the ship before whom she passes in order to opper part of the reeds throughout the fire- approach the enemy, should escort her thither, room ; and upon the composition to lay double and assist her with an armed boat, or whatever quick-match upon all the reeds, in all the succour may be necessary in her situation. troughs: the remainder of the composition to be Among the most formidable contrivances ever spread over all the fire-room. He is then to used, either as a fire-ship or explosion-vessel, is cast off all the covers of the fire-barrels, and that which was used to destroy the bridge of tang the quick-match loose over their sides, and boats at the siege of Antwerp, in the year 1585; place leaders of quick-match from the reeds into which an author of that period states to have the barrels, and thence into the vent of the been a ship strongly timbered, containing a chambers, in such a manner as to be certain of v.ulted arch of stone or mortar, filled with 200 their blowing open the ports, and setting fire to barrels of gunpowder, over which were placed the barrels. The troughs of communication large stones of all forms, cannon-shot, iron chains, from each door of the fire-room to the sally- &c., sufficient to destroy a whole city, that were ports must be laid with a strong leader of quick- exploded by a secret fusee, contrived so as not natch, four or five times double : also a cross- to set fire to the charge till the vessel came in piece to go from the sally-port, when the ship is contact with the bridges, which it blew to atoms

[graphic][ocr errors][ocr errors][ocr errors]
« ZurückWeiter »