PONTOONS.
Those called Blanshard’s (from their inventor, Colonel Blanshard, Royal Engineers) are of two descriptions.
1.—LARGE PONTOONS.
Displacement of water, 97½ cubic feet, equals 6088 lb., or 54½ cwt.
The buoyant power of a raft of two pontoons, its own weight deducted, is 77 cwt., about one-half of which is a safe load. Each raft, or one carriage load, forms 2 bays, or 20 ft. 8 in. of bridge: its own weight will sink it about 7 or 8 inches. The crew of a raft consists of 6 rowers, and 1 steersman.
At open order the bridge will pass cavalry, field artillery, or infantry, with closed files.
At close order the bridge will pass any part of a heavy train.
Dimensions, and weight of cylindrical pontoons, manufactured in the arsenal at Woolwich.
| Extreme length. | Diameter. | Weight. | |||
| ft. | in. | ft. | in. | cwt. | |
| Large Pontoon, | |||||
| with hemispherical ends | 22 | 3 | 2 | 8 | 4 |
| Small Pontoon, | |||||
| with conical ends | 15 | 0 | 1 | 8 | 1¼ |
| ONE CARRIAGE LOAD. | |||||||||||
| Dimensions. | |||||||||||
| Number. | Length.* | Breadth. | Depth. | Weight. | |||||||
| ft. | in. | ft. | in. | ft. | in. | cwt. qrs. lb. | |||||
| Pontoons | 2 | 22 | 2 | 7 | 2 | 7 | 9 | 1 | 9 | ||
| Baulks | 12 | 14 | 2 | 5 | 3 | 5 | 1 | 1 | |||
| Chesses | 8 | 12 | 1 | 2 | 1½ | 1 | 3 | 19 | |||
| Half-chesses | 4 | 11 | 5 | 1½ | 1 | 3 | 0 | ||||
| Gunnels | 2 | 12 | 1 | 2 | 4 | 1 | 3 | 19 | |||
| Side-pieces | 5 | 10 | 4 | 5 | 2½ | 1 | 1 | 0 | |||
| Anchor | 1 | 3 | 1 | ||||||||
| Buoy | 1 | 3 | |||||||||
| Cable (20 fathoms) | 1 | 168 | 3 | 3 | 1 | 18 | |||||
| Oars | 7 | 14 | 3 | 14 | |||||||
| Boat-hook | 1 | 14 | 7 | ||||||||
| { Body | 3 | 8 | 9 | 4 | 20 | ||||||
| Lashings | { Gunnel | 4 | 15 | 1 | 1 | } | 8 | ||||
| { Carriage | 4 | 22 | 1 | 1 | } | ||||||
| Rack-sticks, and lashings | 8 | 14 | |||||||||
| Buoy-line | 1 | 60 | 1½ | 1½ | 5 | ||||||
| Breast-line | 1 | 60 | 1½ | 1½ | 5 | ||||||
| 31 | 1 | 0 | |||||||||
| Weight of Carriage | 1 | 13 | 3 | 20 | |||||||
| Total | 45 | 0 | 20 | ||||||||
| * The length includes the hemispherical ends. | |||||||||||
2.—SMALL PONTOONS.
Five pontoons, with their appurtenances, form the load of one carriage. Length, 15 feet; diameter, 1 foot 7 inches; displacement, 27½ cubic feet; buoyancy, 1718 lb., or 15¼ cwt., from which deduct 2 cwt. for the weight of pontoon, and share of superstructure. A bridge of this nature is so light that it may be made on shore, and carried by hand entire. It will support as many men as can be placed on it, and, by removing the chesses over the gunnels, it may be bent so as to be passed without difficulty down a steep bank, or counterscarp.
| ONE CARRIAGE LOAD. | ||||||||||
| Dimensions. | ||||||||||
| Number. | Length.* | Breadth. | Depth. | Weight. | ||||||
| ft. | in. | ft. | in. | ft. | in. | cwt. qrs. lb. | ||||
| Pontoons | 5 | 15 | 1 | 7 | 1 | 7 | 5 | 0 | 0 | |
| Gunnels | 5 | 8 | 4 | 9 | 3 | 3 | 12 | |||
| Baulks | 30 | 6 | 6 | 3 | 1½ | 1 | 1 | 9 | ||
| Chesses | 20 | 8 | 1 | 4 | 1½ | 4 | 0 | 20 | ||
| Paddles, used as side-pieces | 5 | 1 | 27 | |||||||
| Rack-sticks, and lashings | 10 | 6 | ||||||||
| Carriage lashings | 2 | 5 | ||||||||
| Anchor, and cable | 1 | 2 | 0 | |||||||
| 12 | 1 | 23 | ||||||||
| Weight of the Carriage | 1 | 9 | 0 | 0 | ||||||
| Total | 21 | 1 | 23 | |||||||
| * The length includes the ends. | ||||||||||
SCALING LADDERS.
Scaling ladders are made in portions, 12 feet, and 7½ feet long; which are joined together by placing the end of one portion into staples at the end of another, and securing them together with a lashing of rope. Four men are sufficient to carry an 18 feet scaling ladder.
PART XI.
FIREWORKS.
CANDLES, ROMAN.
When the case has been properly finished, and the end secured with strong twine, ram in a little dry clay, then put in a small quantity of corned powder, and over this a small piece of paper; after which as much of the composition is to be put in as will, when rammed down, fill the case about one-sixth of the length. Over this a piece of paper is placed, covering about two-thirds of the diameter, on which a little powder is laid, and then a ball, or star. Some more composition is then poured in, and pressed lightly down till the case is about one-third full, when it is to be rammed down by gentle strokes; after which, put in another small piece of paper, powder, and star, over which pour in some more composition, ram down gently, and continue thus until the case is filled, when it will contain about five stars; after which it is capped, and primed. Roman candles should be placed in rows on a stand, some of them being perpendicular, and others at angles, not, however, exceeding 45 degrees.
Compositions.
1. Mealed powder, ½ lb. Sulphur, ½ lb. Saltpetre, 2½ lb. Glass dust, ½ lb.
2. Mealed powder, 1 lb. Charcoal, ½ lb.
3. Signal rocket composition.
CANDLES, BLUE.
Saltpetre, ¼ oz. Powder, ½ oz. Sulphur, 1 oz.
CRACKERS.
The case is made of cartridge paper, the dimensions required being 15 inches by 3½ inches. First fold down one edge, about ¾ of an inch broad, then turn down the double edge about ¼ of an inch, and bend back the single edge over the double fold, so as to form within a channel, which is to be filled with mealed powder, not ground very fine; the powder is then to be covered by the folds on each side, and the whole is to be pressed by a flat ruler; and the part containing the powder is to be folded into the remainder of the paper, every fold being pressed down. The cracker is then doubled backwards, and forwards in folds about 2¼ inches, which are pressed quite close, and a piece of twine is passed twice round the middle across the folds, and the joinings secured by causing the twine to take a turn round the middle at each fold successively; one of the ends of the folds may be doubled short under, which will produce an extra report; the other must project a little beyond the rest for the purpose of being primed.
EARTHQUAKE, ARTIFICIAL.
Mix together four pounds of iron sand, and four pounds of sulphur; and after making it into a paste with water, bury it a little depth in the ground. In ten or twelve hours, if the weather be warm, the earth will swell up, and burst; flames will also issue out, scattering around a yellow and black dust.
FIRES OF VARIOUS COLOURS.
White fire is made by mixing powder with iron sand, or filings.
Red fire is made by mixing powder with iron sand of the first order.
Silver colour is made by introducing raspings of ivory.
Pale white colour is made by mixing camphor with the composition.
Lemon colour is produced from raspings of yellow amber.
Russet colour is produced from crude antimony.
Red flame, inclining to brown, is produced by Greek pitch.
Dusky flame is produced by black pitch.
Bluish flame is produced by introducing sulphur in a moderate quantity.
Green flame is made from the introduction of sal ammoniac, and verdigris.
White flame: saltpetre, sulphur, mealed powder, and camphor; the saltpetre must be the chief part.
WILDFIRE, WHICH BURNS UNDER WATER.
Mix well together equal quantities of sulphur, naphtha, bitumen, pitch, and gum.
GERBES.
Gerbes consist of strong cylindrical cases of thick paper, filled with brilliant composition, and sometimes with balls, or stars. Gerbes throw up into the air luminous and sparkling jets of fire; and when arranged in a circular manner, as the radii of a circle, they form what is called a fixed sun. The thickness of the cases for brilliant fire must be a fourth part of the diameter, and for Chinese fire a sixth part. The case is loaded on a nipple, having a point equal in length to the same diameter, and in thickness to a fourth part of it; but as it generally happens that the mouth of the jet becomes larger than is necessary for the effect of the fire, the case should be first charged by filling it to a height equal to a fourth part of the diameter, with clay, which must be rammed down. When the charge is completed with the composition, the case should be closed with a tompeon of wood, and then choked. The train, or match, must be of the same composition as that employed for loading, otherwise the jet would be subject to burst. Charged cases may be pierced with two holes near the neck, in order to have three jets; or, if a top pierced with a number of holes be added to them, they will imitate a bubbling fountain. Jets intended for representing sheets of fire ought not to be choked. They must be placed in a horizontal position, or inclining a little downwards.
Composition for Gerbes, or jets of fire.
Key:
S = Saltpetre.
P = Pulverized powder.
Su = Sulphur.
C = Charcoal.
| JETS. | S | P | Su | C | Iron sand, or filings. | |||||
| lb. | oz. | lb. | oz. | oz. | oz. | oz. | ||||
| ·4 of an inch or less interior diameter | { Chinese fire | 1 | 1 | 8 | 2 | |||||
| { White fire | 1 | 8 | 3 | 2 | Sand, 1st order | 8 | ||||
| ·5 to 1 inch diameter | { Brilliant fire | 1 | Filings | 5 | ||||||
| { White fire | 1 | 8 | 2 | |||||||
| { Chinese fire | 1 | 4 | 5 | 5 | Sand, 3rd order | 12 | ||||
| 1·1 to 1·5 diameter | { | 1 | 4 | 7 | 5 | Mixed sand | 12 | |||
| { | 1 | 8 | 5 | |||||||
| { | 2 | 2 | 8 | |||||||
The saltpetre, powder, and charcoal, are three times sifted through a hair sieve; the iron sand is besprinkled with sulphur, after being moistened with spirits of wine, that the sulphur may adhere to it, and they are then mixed together. The sulphuretted sand is then spread over the first mixture, and the whole is mixed with a ladle only, for if a sieve were employed, it would separate the sand from the other materials.
When sand larger than the 2nd order is used, the composition is moistened with spirits of wine, so that it forms itself into balls, and the jets are then loaded with them.
IRON FILINGS.
These filings must be quite clean, and free from rust. They must be thoroughly mixed with the compositions of which they form one of the ingredients; which, however, will not afterwards keep in good order longer than a week, as the moisture contracted by saltpetre rusts the filings, and destroys the effect they are intended to produce.
IRON SAND, OR POUNDED IRON.
Having broken a cast-iron plate, or iron pot, to pieces, on an anvil, pulverize the fragments till the grains are not larger than radish seed, then sift them through six graduated sieves to separate the different sizes; and preserve these six different kinds in a very dry place, in closely-corked bottles. The grains which pass through the first or finest sieve, are called Sand of the 1st order, and those that pass through the second sieve, Sand of the 2nd order, &c. Compositions into which iron filings, or sand, are introduced, must not be driven hard, for fear of accidents by explosion.
LEADERS, OR PIPES OF COMMUNICATION.
These are small tubes of paper, of lengths adapted to the distances to which they are to extend. The paper is cut into slips two or three inches broad, or sufficient to go four times round the formers, which are about one-fourth of an inch diameter. Brass wire formers are the best, and should be oiled to prevent the paper sticking. Quick match is inserted in these tubes, but must be made to go in easily. The quick match should project an inch beyond each end of the leader, and should be inserted into the mouths of the cases of the fireworks with a small quantity of mealed powder. The leaders must not be placed too near, or cross each other so as to touch, as it may happen that the fire from one may communicate to another, and destroy thereby the intended arrangements.
MARROONS.
Marroons are boxes containing from 1 to 6 ounces of powder. They are made either on a square, or round former, and the ends of the paper are pasted down, and well welded round with kitted twine worked over cross-ways. A hole is bored into the case, and a match inserted.
MEALING GUNPOWDER.
A small quantity of powder being placed on a table with a rim round it, is rubbed down with a scored wooden mealer until all the grains are broken, and it becomes sufficiently fine to pass through a lawn sieve.
PASTE FOR REPRESENTING ANIMALS, ETC., IN FIRE.
Reduce sulphur to an impalpable powder, and having formed it into a paste with starch, cover with it the figure intended to be represented on fire, which must, however, have been previously coated over with clay, to prevent it from being burnt. When covered with the paste, besprinkle it, while still moist, with mealed powder; and when perfectly dry, arrange some matches on the principal parts, so that fire may be speedily communicated to every part of it. The same paste may be employed to form festoons, garlands, &c., the flowers of which might be imitated by fires of different colours, and could be formed on the frieze of a piece of architecture, covered with clay to preserve the stone, or wood from the effect of the fire. The Chinese imitate grapes exceedingly well, by mixing powdered sulphur with the pulp of the jejube, instead of flour-paste or starch.
PORTFIRES FOR ILLUMINATIONS.
The cases are made of three or four rounds of thin paper, the last round being pasted; they are from two to five-eighths of an inch in diameter, and from two to six inches long; they are pinched close at one end, and left open at the other. In filling them, a small quantity of the composition must be put in at a time, ramming it lightly, so as not to break the case.
Compositions.
1. Saltpetre, 1 lb.; sulphur, 8 oz.; mealed powder, 6 oz.
2. Amber lights: Mealed powder, 9 oz.; amber, 3 oz.
3. Saltpetre, 2 lb.; sulphur, 3 lb.; antimony, 1 lb.
4. Saltpetre, 3½ lb.; sulphur, 2½ lb.; mealed powder, 1 lb.; antimony, ½ lb.; glass dust, 4 oz.; brass dust, 1 oz.
Note.—Compositions No. 3, and 4, driven 1¼ inch in a one ounce case, will burn one minute.
RAIN, GOLD, AND SILVER.
Fill small paper cases, or goose quills, with the composition, and place upon the mouth of each some moist powder, both to keep in the composition, and to serve as a match. If the head of a rocket be loaded with these cases or quills, a shower of fiery rain will be produced at the extreme range of the rocket.
Compositions.
Gold rain.
1. Saltpetre, 1 lb.; mealed powder, 4 oz.; sulphur, 4 oz.; brass dust, 1 oz.; sawdust, 2¼ oz.; glass dust, 6 drs.
2. Mealed powder, 12 oz; saltpetre, 2 oz.; charcoal, 4 oz.
3. Saltpetre, 8 oz.; sulphur, 2 oz.; glass dust, 1 oz.; antimony, ¾ oz.; brass dust, ¼ oz.; sawdust, 12 drs.
Silver rain.
1. Saltpetre, 4 oz.; sulphur, mealed powder, and antimony, each 2 oz.; sal prunella, ½ oz.
2. Saltpetre, 8 oz.; sulphur, 2 oz.; charcoal, 4 oz.
3. Saltpetre, 1 lb.; antimony, 6 oz.; sulphur, 4 oz.
4. Saltpetre, 4 oz.; sulphur, 1 oz.; powder, 2 oz.; steel dust, ¾ oz.
ROCKETS, LINE.
Any rocket which is not very large, may be made to run along an extended rope. For this purpose affix to the rocket an empty case, and introduce therein the rope which is to carry it, placing the head of the rocket towards that side to which it is intended to move. Two rockets with an empty case may be similarly used, and may be made to move in a retrograde direction by placing them with their heads reversed, and a leader to communicate from the head of the rocket to be first ignited to the tail of the second.
ROCKETS, SIGNAL.
Composition.
Pulverized saltpetre, 4 lb.; sublimated sulphur, 1 lb.; dogwood charcoal, 1 lb. 8 oz.
The charcoal is first pounded fine enough to pass through a wire sieve (No. 3). The saltpetre and sulphur are each separately passed through a fine hair sieve, then mixed well together with a copper slice, and passed three times through the hair sieve. The charcoal is then spread on a tray, and the saltpetre and sulphur sifted a fourth time on it, and the whole being carefully mixed with a hard brush, is afterwards passed four times through the wire sieve.
To each ladleful of composition, 25 blows are given for the pound, and 21 for the half-pound rocket.
Twenty-eight ladlesful of composition (7½ oz.) are required to complete the pound, and twenty-five (5 oz.) the half-pound rocket.
To prevent accidents in driving rockets, &c., the workman should keep his body erect, the drift being well cleaned after each ladleful; and while driving, it should be moved backward, and forward by a pair of holders.
Rockets are driven 3½ calibres hollow, 1 calibre solid, and ½ calibre with clay.
| Moulds. | |||
| Length. | Diameter. | ||
| 1 Pounder | Exterior | 14 inches | 3·9 |
| Interior | 10·5 ” | 1·7 | |
| ½ Pounder | Exterior | 11·6 ” | 2·3 |
| Interior | 8·5 ” | 1·3 | |
| Spindles. | ||||
| Diameter. | ||||
| Top. | Middle. | Bottom. | Length. | |
| 1 Pounder | ·2 | ·35 | ·5 | 6·4 |
| ½ Pounder | ·2 | ·3 | ·4 | 5·2 |
| Drifts. | ||||
| Length. | Diameter. | Hollowed. | No. | |
| 1 Pounder | { 12·1 inches | 1·1 | 6·5 | 1 |
| { 10 ” | 1·1 | 5·7 | 2 | |
| { 7·3 ” | 1·1 | 2·5 | 3 | |
| { 6·8 ” | 1·1 | Solid | 4 | |
| ½ Pounder | { 9·3 ” | ·9 | 5·4 | 1 |
| { 7·1 ” | ·9 | 2·3 | 2 | |
| { 4 ” | ·9 | Solid | 3 | |
The rocket is primed with mealed powder, and spirits of wine.
When complete, the length of the pound rocket is 15½ inches; and the half-pound 12 inches; the weight of the pound rocket and stick is 1¾ lb.; and the half-pound, 13 oz.
| Length of sticks for rockets. | |||
| 1-Pounder rocket | 8 feet. | Half-pounder | 6 feet 4 inches. |
| Star compositions. | |||
| No. 1. | |||
| Saltpetre, pulverized | 8 lb. | Isinglass, dissolved | 3½ oz. |
| Sulphur, sublimated | 2 lb. | Vinegar | 1 quart. |
| Antimony, pounded | 2 lb. | Spirits of wine | 1 pint. |
2. White stars. Mealed powder, 4 oz.; saltpetre, 12 oz.; sulphur vivum, 6 oz.; oil of spike, 2 oz.; camphor, 5 oz.
3. Blue stars. Mealed powder, 8 oz.; saltpetre, 4 oz.; sulphur, 2 oz.; spirits of wine, 2 oz.; oil of spike, 2 oz.
4. Coloured, or variegated stars. Mealed powder, 8 drs.; rockpetre, 4 oz.; sulphur vivum, 2 oz.; camphor, 2 oz.
5. Brilliant stars. Saltpetre, 3½ oz.; sulphur, 1½ oz.; mealed powder, ¾ oz., worked up with spirits of wine.
6. Common stars. Saltpetre, 1 lb.; sulphur, 4 oz.; antimony, 4¾ oz.; isinglass, ½ oz.; camphor, ½ oz.; spirits of wine, ¾ oz.
7. Tailed stars. Mealed powder, 3 oz.; sulphur, 2 oz.; saltpetre, 1 oz.; charcoal, coarsely ground, ¾ oz.
8. Drove stars. No. 1. Saltpetre, 3 lb.; sulphur, 1 lb.; brass dust, 12 oz.; antimony, 3 oz.
No. 2. Saltpetre, 1 lb.; antimony, 4 oz.; sulphur, 8 oz.
9. Fixed pointed stars. Saltpetre, 8½ oz.; sulphur, 2 oz.; antimony, 1 oz. 10 drs.
10. Stars of a fine colour. Sulphur, 1 oz.; mealed powder, 1 oz.; saltpetre, 1 oz.; camphor, 4 drs.; oil of turpentine, 4 drs.
The dry ingredients are well mixed, and sifted through a hair sieve: the isinglass dissolved over a fire with vinegar, and the spirits of wine afterwards added, and with which the dry composition is thoroughly mixed. It is then formed on moulds, and a hole is left in the middle to assist its ignition. Thirty-six stars are put in a 1-pounder, and twenty-two in a half-pounder rocket.
A great variety of figures may be represented in the air by attaching to a large rocket several small rockets, or small cases filled with the composition; or serpents may be attached to the rocket by means of packthread.
SALTPETRE, PULVERIZED.
Sixteen pounds of refined lakepetre are put into a copper vessel, to which four quarts of water are added. It is placed over a charcoal fire to boil; as the water evaporates it is well stirred with copper-shod spatulas or paddles, occasionally taking it off the fire, until the evaporation ceases; and when brought to a fine powder it is sifted through a hair sieve, and spread on paper to cool.
To extract saltpetre from damaged gunpowder.
Dissolve the powder in warm water, filter the solution through fine linen bags, and then evaporate the water by boiling it, until the solution is of sufficient strength to crystallize.
SERPENTS, OR SQUIBS.
The case is made by rolling stout cartridge paper in slips of 6 or 8 inches in breadth three times round a former, and pasting down the last fold. The case, having been choked at one end, is filled about two-thirds with the composition, and a small piece of paper is inserted, over which powder is placed, and this end is secured with twine. At the other extremity, moist powder with touch-paper is inserted. To introduce the composition into the case, a quill, cut into the form of a spoon, may be employed, and the composition must be rammed down by a few strokes of a mallet on an iron rod tipped with brass.
| Composition. | |||
| 1. | lb. oz. | 2. | lb. oz. |
| Mealed powder | 1 8 | 1 0 | |
| Charcoal | 4 | 1 | |
| Sulphur | 1 | 0 | |
| Saltpetre | 3 | 1¾ | |
SHELLS, OR AERIAL GLOBES.
These globes are made of wood, and their thickness is equal to about a twelfth part of their diameters. The usual charge is an ounce of powder for a shell of 4 lb. weight, and 2 ounces for a shell of 8 lb. They may be fired from any mortars that have not a chamber.
To form the shell.
Two wooden hemispheres (with a fuze hole) are joined firmly together, enclosing stars, squibs, rain, &c. A small quantity of powder is inserted to explode the shell, by means of a fuze.
SHOWERS OF FIRE.
To form a shower of fire, mould small paper cases on an iron rod, two-tenths of an inch in diameter, and 2½ inches in length. They must not be choked, as it will be sufficient to twist the end of the case, and having put the rod into it, beat it to make it assume its form. When the cases are filled (which is done by immersing them in the composition) fold down the other end, and then apply a match. They must be fixed on a frame with leaders, to be fired simultaneously.
Compositions.
Chinese fire. Mealed powder, 1 lb.; sulphur, 2 oz.; iron filings, 5 oz.
Ancient fire. Mealed powder, 1 lb.; charcoal, 2 oz.
Brilliant fire. Mealed powder, 1 lb.; iron filings, 4 oz.
The Chinese fire is the best of the above compositions.
SPECKIE.
Brilliant, and diversified displays of fireworks may be readily exhibited by means of speckie, or lances. Illuminated designs of figures, &c., are represented by affixing on a black board small cases filled with various coloured compositions, to which leaders must be attached. The cases are fastened on with glue, and red lead mixed together.
| Compositions. | ||||||||||
| White. | Yellow. | Blue. | Yellow. | Yellow. | ||||||
| lb. | oz. | lb. | oz. | lb. | oz. | lb. | oz. | lb. | oz. | |
| Saltpetre | 2 | 4 | 8 | 1 | 2 | 1 | 2 | |||
| Sulphur | 8 | 1 | 4 | 8 | ½ | |||||
| Mealed powder | 4 | 12 | 10 | 8 | ||||||
| Antimony, crude | 4 | |||||||||
| Gum Succum | 8 | |||||||||
| Antimony, prepared | 8 | |||||||||
| Basket salt | 6 | |||||||||
| Gamboge | 3 | |||||||||
Stars, crosses, revolving suns, &c., being fixed on the wooden frame with the speckie, will form a brilliant display.
SPUR FIRE.
| Composition. | |||
| 1. | lb. oz. | 2. | lb. oz. |
| Saltpetre | 4 8 | 1 | |
| Sulphur | 2 | 8 | |
| Lamp black | 1 8 | 4 quarts. | |
The saltpetre and sulphur must be first sifted together, and then put into a marble mortar with the lamp black. These ingredients must be thoroughly mixed with a wooden pestle. The composition, if rubbed too much, will be too fierce, and hardly show any stars; and on the contrary, when not mixed enough, will be too weak, and throw out an obscure smoke, and lumps of dross without any stars. This composition is generally rammed in 1, or 2 ounce cases, about five, or six inches long, but not driven very hard. Cases filled with spur fire may be used in rooms without any danger of setting fire to the furniture, &c., and some of them being placed round a transparent pyramid of paper, and fired in a large room, make a very pretty appearance.
SUNS, OR WHEELS, FIXED, AND MOVEABLE.
None of the pyrotechnic inventions can be applied with so much success in artificial fireworks, as suns, or wheels, of which there are two kinds, fixed, and revolving.
FIXED SUNS.
Construct a circular piece of wood, into the circumference of which screw 12 or 15 pieces in the form of radii, and to these attach jets of fire, the mouth of each of which must be towards the circumference of the frame; and leaders being affixed to all the jets, they will, when ignited, produce the appearance of a radiated sun. The wheel is fixed vertically. The jets may be arranged so as to cross each other in an angular manner, in which case a star, or cross of Malta will be formed. To produce a very brilliant effect, these suns may be made with several rows of jets.
REVOLVING SUNS.
Provide a wooden wheel of the requisite size, and bring it into perfect equilibrium around its centre, in order that the least effort may make it turn round. Attach to the circumference of it jets placed in the direction of the circumference; and affix leaders of match to communicate the fire from jet to jet, according as may be required. When fire is applied to one of the jets, the recoil will immediately cause the wheel to revolve, unless it should be too ponderous or large: therefore, when these suns are intended to be of a considerable size, that is, when they consist of twenty jets, fire must be communicated at the same time to the 1st, 6th, 11th, and 16th, from which it will proceed to the 2nd, 7th, 12th, and 17th, and so on. Four jets will thus make the wheel revolve rapidly. If two similar suns be placed one behind the other, and made to turn round in a contrary direction, they will produce a very brilliant cross fire.
For a sun 5 feet in diameter, the cases should be 8 oz., filled about 10 inches in length with composition.
Four ounce cases will be required for wheels of 14, or 16 inches; if the wheels are larger, 8 oz., 1 lb., or even 2 lb. cases will be required.
The Chinese compositions are intended for cases of nine-tenths of an inch interior diameter, but they will be found to answer for cases as low as four ounces.
TOUCH PAPER.
Dissolve saltpetre in spirits of wine, or water, more or less of the saltpetre, according as the paper is to burn fast, or slow: then dip into the solution blue paper, which, when well saturated, take out, and dry for use. The touch-paper must be cut into slips, placed once round the mouth of the firework, and the end of the paper outside the case should be twisted to a point.
WHEELS, PIN, OR CATHERINE.
The pipe or case is made on a long wire former, about three-sixteenths of an inch in diameter, into which the composition is poured through a funnel, and shaken down. The case is then rolled round a small circle of wood about one inch in diameter, and not more than half an inch thick, with a hole through the centre of it for a nail, or pin. One end of the case is to be pasted round the wood, and each half turn of it secured with sealing-wax, or a strip of paper pasted across the wheel. The end is then primed.
Composition.
Mealed powder, 12 oz.; saltpetre, 3 oz.; sulphur, 1½ oz.
Two ounces of iron sand, or camphor, may be added, but it keeps better without either.
PART XII.
MATHEMATICS.
Mathematics is the science which treats of all kinds of quantity whatever, that can be numbered, or measured.
Arithmetic is that part which treats of numbering.
Fractions treat of broken numbers, or parts of numbers.
Algebra is the art of computing by symbols.
In this science, quantities of all kinds are represented by the letters of the alphabet.
Geometry is the science relating to measurement. By the assistance of geometry, engineers, &c., conduct all their works, take the distances of places, and the measure of inaccessible objects, &c.
Characters, marks, or signs,
which are used in arithmetic, and algebra, to denote several of the operations, and propositions:
+ signifies plus, or addition,
- minus, or subtraction,
× multiplication,
÷ division,
: :: : proportion,
= equality,
√ square root,
∛ cube root,
42 denotes that 4 is to be squared.
43 denotes that 4 is to be cubed.