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tore the scroll of paper just mentioned, and it is entirely wound upon the roller, the part of the paper that is then between being quite opaque, no part of the cascade will be visible; but, as the winch is turned gently and regularly round, the transparent part of the paper will give to the cascade the appearance of fire that descends in the same direction; and the illusion will be so strong that the spectators will think they see a cascade of fire, especially if the figure be judiciously cut out.

PART II. • OF ROCKETS. SECT. 1.-Construction of the Cases,

Rockets may be regarded as the grand basis of all fire-works, which are little more than modifications of their form, and of the materials of which they usually consist. A rocket is a cartridge or case made of stiff paper, which being filled in part with gunpowder, saltpetre, and charcoal, rises of itself into the air, when fire is applied to it. here are three sorts of rockets: small ones the calibre of which does not exceed a pound bullet; that is to say, the orifice of them is equal to the diameter of a leaden bullet which weighs only a pound; for the calibres or orifices of the moulds or the models used in making rockets are measured by the diameters of leaden bullets. Middle sized rockets, equal to the size of a ball of from one to three pounds. And large rockets, equal to a ball of from three to 100 pounds. To give the cartridges the same length and thickness, in order that any number of rockets may be prepared of the same size and force, they are put into a hollow cylinder of strong wood, called a mould. This mould is sometimes of metal; but at any rate it ought to be made of some very hard wood. This mould must not be confounded with another piece of wood, called the former or roller, around which is rolled the thick paper employed to make the cartridge. If the calibre of the mould be divided into eight equal parts, the diameter of the roller must be equal to five of these parts. The vacuity between the roller and the interior surface of the mould, that is to say three-eighths of the calibre of the mould, will be exactly filled by the cartridge. As rockets are made of different sizes, moulds of different lengths and diameters must be provided. The calibre of a cannon is nothing else than the diameter of its mouth; and we here apply the same term to the diameter of the aperture of the mould. The size of the mould is measured by its calibre; but the length of the moulds for different rockets does not always bear the same proportion to the calibre, the length being diminished as the calibre is increased. The length of the mould for small rockets ought to be six times the calibre, but for rockets of the mean and larger size it will be sufficient if the length of the mould be five times or four times the calibre of the moulds. We shall give two tables, one of which contains the calibres of moulds below a pound bullet; and the other

the calibres from a pound to 100 pounds bullet. For making the cartridges, large stiff paper is employed. This paper is wrāpped round the roller, and then cemented by means of common paste. The thickness of the paper, when rolled up in this manner, ought to be about one-eighth and a half of the calibre of the mould, according to the proportion given to the diameter of the roller. But, if the diameter of the roller be made equal to three-fourths the calibre of the mould, the thickness of the cartridge must be a twelfth and a half of that calibre. When the cartridge is formed, the roller is drawn out, by turning it round, until it is distant from the edge of the cartridge the length of its diameter. A piece of cord is then made to pass twice round the cartridge at the extremity of the roller. And into the vacuity left in the cartridge another roller is introduced, so as to leave some space between the two. One end of the pack-thread must be fastened to something fixed, and the other to a stick conveyed between the legs, and placed in such a manner as to be behind the person who chokes the cartridge. The cord is then to be stretched by retiring backwards, and the cartridge must be pinched until there remains only an aperture capable of admitting the piercer. The cord employed for pinching it is then removed, and its place is supplied by a piece of pack-thread, which must be drawn very tight, passing it several times round the cartridge, after which it is secured by means of running knots made one above the other, Besides the roller, a rod is used, which being employed to load the cartridge, must be somewhat smaller than the roller, in order that it may be easily introduced into the cartridge. The rod is pierced lengthwise, to a sufficient depth to receive the piercer, which must enter into the mould, ins unite with it exactly at its lower part. The piercer, which decreases in size, is introduced into the cartridge through the part where it has been choked, and serves to preserve a cavity within it. Its length, besides the nipple or button, must be equal to about twothirds that of the mould. Lastly, if the thickness of the base be a fourth part of the calibre of the mould, the point must be made equal to a sixth of the calibre. It is evident there must be at least three rods, pierced in proportion to the diminution of the piercer, in order that the powder which is rammed in by means of a mallet, may be uniformly packed 3. the whole length of the rocket. It may be easily perceived, also, that these rods ought to be made of some very hard wood, to resist the strokes of the mallet. In loading rockets it is more convenient not to . a piercer. When loaded on a nipple, without a piercer, by means of one massy rod, they are pierced with a bit and a piercer fitted into the end of a bit-brace. Care however must be taken to make this hole suited to the propor

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about two-thirds of the length of the rocket ought to be a sixth of the calibre. This hole must pass directly through the middle of the rocket. In short, experience and ingenuity will suggest what is most convenient, and in what manner the method of loading rockets, which we shall here explain, may be varied. After the cartridge is placed in the mould, pour gradually into it the prepared composition; taking care to pour only two spoonfuls at a time, and to ram it immediately down with the rod, striking it in a perpendicular direction with a mallet of a proper size, and giving an equal number of strokes, for example, three or four each time that a new quantity of the composition is poured in. When the cartridge is about half filled, separate with a bodkin the half of the folds of the paper which remains, and, having turned them back on the composition, press them down with the rod and a few strokes of the mallet, in order to compress the paper on the composition. Then pierce three or four holes in the folded paper, by means of a piercer, which must be made to penetrate to the composition of the rocket. These holes serve to form a communication between the body of the rocket and the vacuity at the extremity of the cartridge, or that part which has been left empty. In small rockets this vacuity is filled with granulated powder, which serves to let them off: they are then covered with paper, and pinched in the same manner as at the other extremity. But in other rockets, the pot containing stars, serpents, and running rockets, is adapted to it, as will be shown hereafter. It may be sufficient however to make, with a bit or piercer, only one hole, which must be neither too large nor too small, such as a fourth part of the diameter of the rocket, to set fire to the powder, taking care that this hole be as straight as possible, and exactly in the middle of the composition. A little of the composition of the rocket must be put into these holes, that the fire may not fail to be communicated to it. It now remains to fix the rocket to its rod, which is done in the following manner:—When the rocket has been constructed as above described, make fast to it a rod of light wood, such as fir or willow, broad and flat at the end next the rocket, and decreasing towards the other. It must be as straight and free from knots as possible, and ought to be dressed, if necessary, with a plane. Its length and weight must be proportioned to the rocket; that is to say, it ought to be six, seven, or eight feet long, so as to remain in equilibrium with it, when suspended on the finger, within an inch, or an inch and a half of the neck. Before it is fired, place it with the neck downwards, and let it rest on two nails, in a direction perpendicular to the horizon. To make it ascend straighter and to a greater height, adapt to its summit a pointed cap or top, made of common paper, which will serve to facilitate its passage through the air. hese rockets, in general, are made in a more complex manner, several other things being added to them to render them more agreeable, such for example as a petard, which is a box of

tin-plate, filled with fine gunpowder, placed on the summit. The petard is deposited on the composition, at the end where it has been filled; and the remaining paper of the cartridge is folded down over it to keep it firm. The petard produces its effect when the rocket is in the air and the composition is consumed. Stars, golden rain, serpents, saucissons, and several other amusing things, may also, as we have seen, be added to them. This is done by adjusting to the head of the rocket, an empty pot or cartridge, much larger than the rocket, in order that it may contain serpents, stars, and o other appendages, to render it more beautiful. Rockets may be made to rise into the air without rods. For this purpose four wings must be attached to them in the form of a cross, and similar to those seen on arrows or darts. In length, these wings must be equal to two-thirds that of the rocket; their breadth towards the bottom should be half their length, and their thickness ought to be equal to that of a card. But this method of making rockets ascend is less certain, and more inconvenient, than that where a rod is used; and for this reason it is rarely employed. We shall now show the method of finding the diameters or calibre of rockets, according to their weight; but we must first observe that a und rocket is that just capable of admitting a eaden bullet of a pound weight, and so of the rest. The calibre for the different sizes may be found by the two following tables, one of which is calculated for rockets of a pound weight and below; and the other for those from a pound weight to fifty pounds.

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The use of this table will be understood merely by inspection; for it is evident that a rocket of twelve ounces ought to be seventeen lines in diameter; one of eight ounces, fifteen lines; one often drachms, six lines and one-third; and so of the rest. On the other hand, if the diameter of the rocket be given, it will be easy to find the weight of the ball corresponding to that calibre. For example, if the diameter be thirteen lines, it will be immediately seen, by looking for that number in the column of lines, that it corresponds to a ball of five ounces.

II. Table of the calibre of moulds from one to fifty pounds ball.

Pounds. Calibre. Pounds. | Calibre. Pounds. Calibre. Pounds. Calibre.
1 100 14 241 27 300 40 341
2 126 15 247 28 304 41 344
3 144 16 252 29 307 42 347
4 158 17 257 30 310 43 350
5 171 18 262 31 314 44 353
6 181 19 267 32 317 45 355
7 191 20 271 33 320 46 358
8 200 21 275 34 323 47 361
9 208 22 280 35 326 48 363
10 215 23 284 36 330 49 366
11 222 24 288 37 333 50 368
12 228 25 292 38 336
13 235 26 296 39 339

The use of the second table is as follows:–If the weight of the ball be given, which we shall suppose to be twenty-four pounds, seek for that number in the column of pounds, and opposite to it, in the column of calibres, will be found the number 288. Then say, as 100 is to nineteen and a half so is 288 to a fourth term, which will be the number of lines of the calibre required; or multiply the number found, that is 288, by nineteen and a half, and from the product, 56-16, cut off the last two figures: the required calibre therefore will be 56.16 lines, or four inches eight lines.

Un the other hand, the calibre being given in lines, the weight of the ball may be found with equal ease: if the calibre, for example, be twenty-eight lines, say as nineteen and a half is to twenty-eight so is 100 to a fourth term, which will be 143.5 or nearly 144. But in the above table, opposite to 144 in the second column, will be found the number three in the first; which shows that a rocket, the diameter or calibre of which is twenty-eight lines, is a rocket of a three pounds ball.

Sect. II.-Composition of The Powden Fon
Rockets, AND THE Mode of FILLING THEM.

The composition of the powder for rockets must be different, according to the different sizes; as that proper for small rockets would be too strong for large ones. This is a fact respecting which almost all the makers of fire-works are agreed. The quantities of the ingredients which experience has shown to be the best are as follow :For rockets capable of containing one or two ounces of composition.—To one pound of gunpowder add two ounces of soft charcoal; or to one pound of gunpowder a pound of the coarse powder used for cannon; or to nine ounces of gunpowder two ounces of charcoal; or to a pound of gunpowder an ounce and a half of saltpetre, and as much charcoal. or rockets of two or three ounces.—To four ounces of gunpowder add an ounce of charcoal; or to nine ounces of gunpowder add two ounces of saltpetre. For a rocket of four ounces.—To four pounds of gunpowder add a pound of saltpetre and four unces of charcoal : you may add also, if you

choose, half an ounce of sulphur; or to one
pound two ounces and a half of gunpowder add
four ounces of saltpetre and two ounces of char-
coal; or to a pound of powder add four ounces
of saltpetre and one ounce of charcoal; or to
seventeen ounces of gunpowder add four ounces
of saltpetre and the same quantity of charcoal;
or to three ounces and a half of gunpowder add
ten ounces of saltpetre and three ounces and a
half of charcoal. But the composition will be
strongest if to ten ounces of gunpowder you add
three ounces and a half of saltpetre and three
ounces of charcoal.
For a rocket of five or sir ounces.—To two
pounds five ounces of gunpowder add half a
pound of saltpetre, two ounces of sulphur, six
ounces of charcoal, and two ounces of iron
filings.
For rockets of seven or eight ounces.—To
seventeen ounces of gunpowder add four ounces
of saltpetre and three ounces of sulphur.
For rockets of from eight to ten ounces.—To
two pounds and five ounces of gunpowder add
half a pound of saltpetre, two ounces of sulphur,
seven ounces of charcoal, and three ounces of
iron filings.
For rockets of from ten to twelve ounces.—To
seventeen ounces of gunpowder add four ounces
of saltpetre, three ounces and a half of sulphur,
and one ounce of charcoal.
For rockets of from fourteen to fifteen ounces.
—To two pounds four ounces of gunpowder add
nine ounces of saltpetre, three ounces of sulphur,
five ounces of charcoal, and three ounces |.
filings.
For rockets of one pound—To one pound of
gunpowder add one ounce of sulphur and three
ounces of charcoal.
For a rocket of two pounds-To one pound
four ounces of gunpowder add two ounces of
saltpetre, one ounce of sulphur, three ounces of
charcoal, and two ounces of iron filings.
For a rocket of three pounds.--To thirty ounces
of saltpetre add seven ounces and a half of sul-
phur and eleven ounces of charcoal.
For rockets of four, five, sir, or seven pounds.
—To thirty-one pounds of saltpetre add four
pounds and a half of sulphur and ten pounds of
charcoal.
For rockets of eight, nine, or ten pounds.--

To eight pounds of saltpetre add one pound four ounces of sulphur and two pounds twelve ounces of charcoal.

We shall here observe, that these ingredients must be each pounded separately and sisted; they are then to be weighed and mixed together, for the purpose of loading the cartridges, which ought to be kept ready in the moulds. The cartridges must be made of strong paper, doubled, and cemented by means of strong paste, made of fine flour and very pure water.

Of Matches.—Before we proceed farther it will be proper to describe the composition of the matches necessary for letting the rockets off. Take linen, hemp, or cotton thread, and double it eight or ten times, if intended for large rockets; or only four or five times, if to be employed for stars. When the match has been thus made as large as necessary, dip it in pure water, and press it between your hands, to free it from the moisture. Mix some gunpowder with a little water, to reduce it to a sort of paste, and immerse the match in it, turning and twisting it till it has imbibed a sufficient quantity of the powder; then sprinkle over it a little dry powder, or strew some pulverised dry powder upon a smooth board, and roll the match over it. By these means you will have an excellent match; which if dried in the sun, or on a rope in the shade, will be fit for use.

Sect. III.-ForMAtroN of Rockets.

The upper part of rockets is generally furnished with some composition, which takes fire when it has reached to its greatest height, emits a considerable blaze, or produces a loud report and whizzing noise. Of this kind are saucissons, maroons, stars, showers of fire, &c. To make room for an artifice of this kind," the rocket is crowned with a part of greater' diameter called a pot. The following is the method of making this pot, and connecting it with the rocket:—

The mould for forming the pot, though of one piece, must consist of two cylindric parts of different diameters. That on which the pot is rolled up must be three diameters of the rocket in length, and its diameter must be three-fourths that of the rocket; the length of the other ought to be equal to two of these diameters, and its diameter to seven-fifths that of the rocket. Having rolled the thick paper, intended for making the pot, twice round the cylinder, a portion of it must be pinched in that part of the cylinder which has the least diameter: this part must be pared in such a manner as to leave only what is necessary for making the pot fast to the top of the rocket, and the ligature must be covered with paper.

To charge such a pot, attached to a rocket. Having pierced three or four holes in the double paper which covers the vacuity of the rocket, pour over it a small quantity of the composition with which the rocket is filled, and by shaking it make a part enter these holes; then arrange, in the pot, the composition with which it is to be charged, taking care not to introduce into it a quantity heavier than the body of the rocket. The whole must be secured by means of a few

small balls of paper, and the pot covered with paper cemented to its edges: let a pointed summit be added to it, and the rocket is fit for use. We shall now give an account of the different artifices with which such rockets are loaded. 1. Of serpents.-Serpents are small flying rockets without rods, which, instead of rising in a perpendicular direction, mount obliquely, and fall back in a zig-zag form without ascending to a great height. The composition of them is nearly the same as that of rockets; and therefore nothing more is necessary than to determine the proportion and construction of the cartridge, which is as follows:—The length of the cartridge may be about four inches; it must be rolled round a stick somewhat larger than the barrel of a goose-quill, and, after being choked at one of its ends, fill it with the composition a little beyond its middle, and then pinch it so as to leave a small aperture. The remainder must be filled with grained powder, which will make a report when it bursts. Lastly, choke the cartridge entirely towards the extremity; and at the other extremity place a train of moist powder, to which, if fire be applied, it will be communicated to the composition, and cause the whole to rise in the air. The serpent, as it falls, will make several turns in a zig-zag direction, till the fire is communicated to the grained powder; on which it will burst with a loud report before it falls to the ground. If the serpent be not choked towards the middle, instead of moving in a zig-zag direction, it will ascend and descend with an undulating motion, and then burst as before. The cartridges of serpents are generally made with playing cards. These cards are rolled round a rod of iron or hard wood, a little larger, as already said, than the barrel of a goose-quill. To confine the card, a piece of strong paper is cemented over it. The length of the mould must be proportioned to that of the cards employed, and the piercer of the nipple must be three or four lines in length. These serpents are loaded with bruised powder, mixed only with a very small quantity of charcoal. To introduce the composition into the cartridge, a quill, cut into the form of a spoon, may be employed; it must be rammed down by means of a small rod, to which a few strokes are given with a small mallet. When the serpent is half loaded, instead of pinching it in that part, you may introduce into it a vetch seed, and place granulated powder above it to fill up the remainder. Above this powder place a small pellet of chewed paper, and then choke the other end of the cartridge. If you are desirous of making larger serpents, cement two playing cards together; and, that they may be managed with more ease, moisten them a little with water. The match consists of a paste made of bruised powder, and a small quantity of water. 2. Marroons.—Marroons are small cubical boxes, filled with a composition proper for making them burst, and may be constructed with great ease. Cut a piece of pasteboard, according to the method taught in geometry to form the cube; ioin these squares at the edges, leaving only one to be cemented, and fill the cavity of the cube with grained powder; then cement strong paper in various directions over this body; and wrap round it two rows of pack-thread, dipped in strong glue; then make a hole in one of the corners, and introduce into it a match. If you are desirous to have luminous marroons, that is to say, marroons which, before they burst in the air, emit a brilliant light, cover them with a paste the composition of which will be given hereafter for stars; and roll them in pulverised gunpowder to serve as a match or communication. 3. Saucissons.—Marroons and saucissons differ from each other only in their form. The cartridges of the latter are round, and must be only four times their exterior diameter in length. They are choked at one end in the same manner as a rocket; and a pellet of paper is driven into the aperture which . been left, in order to fill it up. They are then charged with grained powder, above which is placed a ball of paper gently pressed down, to prevent the powder from being bruised; the second end of the saucisson being afterwards choked, the edges are pared on both sides, and the whole is covered with several turns of pack-thread, dipped in strong glue, and then left to dry. When you are desirous of charging them, pierce a hole in one of the ends, and apply a match, in the same mannet as martoons. 4. Stars.-Stars are small globes of a composition which emits a brilliant light, which may be compared to the light of the stars in the heavens. These balls are not larger than a nutmeg or musket bullet, and when put into the rockets must be wrapped up in tow, prepared for that purpose. The composition of these stars is as Jollows :--To a pound of fine gunpowder well pulverised add four pounds of saltpetre, and two pounds of sulphur. When these ingredients are thoroughly incorporated, take about the size of a nutmeg of this mixture, and having wrapt it up in a piece of linen rag, or of paper, form it into a ball; then tie it closely round with a packthread, and pierce a hole through the middle of it, sufficiently large to receive a piece of lo tow, which will serve as a match. This star, when lighted, will exhibit a most beautiful appearance; besides the fire, as it issues from the two ends of the hole in the middle, will extend to a greater distance, and make it appear much larger. If you are desirous to employ a moist composition in the form of a paste, instead of a dry one, it will not be necessary to wrap up the star in any thing but prepared tow; because, when made of such paste, it can retain its spherical figure. There will be no need also of piercing a hole in it, to receive the match; because, when newly made, and consequently moist, it may be rolled in pulverised gunpowder, which willadhere to it. This powder,when kindled, will serve as a match, and inflame the composition of the star, which in falling will form itself into tears. Another method of making rockets with stars.Mix three ounces of saltpetre, with one ounce of sulphur, and two drachms of pulverised gunpowder; or mix four ounces of sulphur with the same quantity of saltpetre and eight ounces

of pulverised gunpowder. When these materials have been well sifted, besprinkle them with brandy, in which a little gum has been dissolved, and then make up the star in the following manner:-Take a rocket mould, eight or nine lines in diameter, and introduce into it a nipple, the piercer of which is of a uniform size throughout, and equal in length to the height of the mould. Put into this mould a cartridge, and by means of a pierced rod load it with one of the preceding compositions; when loaded, take it from the mould, without removing the nipple, the piercer of which passes through the composition, and then cut the cartridge quite round into pieces of the thickness of three or four lines. The cartridge being thus cut, draw out the piercer gently, and the pieces, which resemble the men employed for playing at drafts, pierced through the middle, will be stars, which must be filed on a match thread, which, if you choose, may be covered with tow.

To give more brilliancy to stars of this kind, a cartridge thicker than the above dimensions, and thinner than that of a flying rocket of the same size, may be employed; but, before it is cut into pieces, five or six holes must be pierced in the circumference of each piece to be cut. When the cartridge is cut, and the pieces have been filled, cement over the composition small bits of card, each having a hole in the middle, so that these holes may correspond to the place where the composition is pierced.

Remarks.-1. There are several other methods of making stars, which it would be too tedious to describe. We shall therefore only show how to make étoiles a pet, or stars which give a report as loud as that of a pistol or musket. Make small saucissons, as taught in the third section; only it will not be necessary to cover them with. pack-thread: it will be sufficient if they are pierced at one end, in order that you may tie to it a star constructed according to the first method, the composition of which is dry; for, if the composition be in the form of a paste, there will be no need to tie it. Nothing will be necessary in that case but to leave a little more of the paper hollow at the end of the saucisson which has been pierced, for the purpose of introducing the ..". and to place in the vacuity, towards the neck of the saucisson, some grained powder, which will communicate fire to the saucisson when the composition is consumed.

2. As there are some stars which in the end become petards, others may be made which shall conclude with becoming serpents. But this may be so easily conceived and carried into execution that it would be losing time to enlarge further on the subject. We shall only observe that these stars are not in use, because it is difficult for a rocket to carry them to a considerable height in the air : they diminish the effect of the rocket or saucisson, and much time is required to make them.

SECT. IV.-Of Cour ANTINs of Rockets which FLY Along A Rope.

A common rocket, which however ought not to be very large, may be made to run along an extended rope. For this purpose affix to the

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