the half-pound 12 inches; the weight of the pound rocket and stick is 1 lb.; and the half-pound, 13 oz. 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. Brilliant stars. Saltpetre, 3 oz.; sulphur, 1 oz.; mealed powder, oz., worked up with spirits of wine. 5. Common stars. Saltpetre, 1 lb.; sulphur, 4 oz.; antimony, 42 oz.; isinglass,oz.; camphor, oz.; spirits of wine, oz. 6. Tailed stars. Mealed powder, 3 oz.; sulphur, 2 oz.; saltpetre, 1 oz.; charcoal, coarsely ground, oz. 7. Drove stars. Saltpetre, 1 lb.; antimony, 4 oz.; sulphur, 8 oz. 8. Fixed pointed stars. Saltpetre, 8 oz.; sulphur, 2 oz.; antimony, 1 oz. 10 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 funnel, and wire are used, the wire being pressed hard down upon the composition. These globes are made of wood, and their thickness is equal to abont 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, OR CASCADES. Make a case an inch in diameter, the thickness of paper being about th of an inch. Stop up one end with clay. Drive it with the composition firmly with a drift and mallet, a ladleful at a time. These cases must be fixed on a frame with leaders, to be fired simultaneously. Chinese fire. Compositions. Mealed powder, 1 lb.; saltpetre, 2 oz.; iron filings, very fine, 8 oz.; charcoal, very fine, 5 oz. Ancient fire. Mealed powder, 1 lb.; charcoal, 2 oz. Brilliant fire. Mealed powder, 1 lb.; iron filings, 4 oz. The charcoal, and iron filings ought to pass through a 60 mesh sieve. The saltpetre, and sulphur must be first sifted together, and then put into a marble mortar with the lampblack. 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 flooring, 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 round 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 be 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 water; more or less of the saltpetre, according as the paper is to burn fast, or slow: then dip into the solution blue The paper, which, when well saturated, take out, and dry for use. 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 threesixteenths 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, 11⁄2 oz. Two ounces of iron sand, or camphor, may be added, but it keeps better without either. PART XIII. 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: Note.--14 pounds = 1 stone; 2 stones = 1 quarter. 1 lb. Avoirdupois weight = 14 oz. 11 dwts. 15 grs. Troy. 1 oz. ditto 18 dwts. 5 do. 1 dr. ditto |