A System of Pyrotechny. James Cutbush
the effect of which is brilliant and striking. Besides the rapid combustion of the composition, the stars, when the fire comes to the meal-powder, are thrown out by it in succession, and to the height of one hundred and more feet. We have also, in this instance, the effect of the rocket composition, and that of gunpowder; the last of which, acting in the case in the same manner as powder in a musket on a ball, throws the stars to a great height. Hence the effect is varied according to the manner of loading the case; and by employing alternately the substances we have mentioned, the effects follow in regular succession. The use of gunpowder in this manner, is strikingly shown in many other fire-works. When, for instance, stars, serpents, &c. forming the furniture of a rocket, are to be dispersed, gunpowder is put in the head or conical cap of the rocket, and fire is communicated to it at the moment the rocket has arrived at its extreme elevation. In the bursting of paper shells, the same effect ensues, and the different substances contained in the shell are dispersed in every direction.
Balloons are nothing more than shells made either of paper, or wood turned hollow. These balloons are discharged from mortars, or fire-pots, sometimes called pots of ordnance. They are merely cylinders of various diameters, made of paper and very thick, or of metal, and are furnished at their bottom with a conical cavity lined with copper, designed to hold the charge of powder. When the balloon is filled, (see Balloons), it is introduced into the mortar over the charge, and being furnished with a fuse as in other shells, takes fire the moment the powder is inflamed. According to the quantity of powder made use of, so will be the height of ascension. By determining the ascension, and the time required for the fuse to burn, and communicate fire to the shell, we may fix the precise moment for its explosion. The powder contained in the shell is sufficient only to burst it, and disperse its contents. (See Mortars, Fire-pots, and pots of Aigrette.)
A balloon will contain more stars, serpents, &c. than the head of an ordinary rocket, and the effect which they produce, must of course be more striking. The Congreve rocket, calculated as it is to convey carcass composition, balls, grenades, &c. if furnished with stars, crackers, &c. would produce an effect equal, if not superior to the balloon.
We remarked, that, in common sky rockets, the charges consist of a mixture of gunpowder, saltpetre, and charcoal, with occasionally other additions, as steel-filings. Rocket-stars, on the contrary, are usually formed of mealed powder, saltpetre, sulphur, and sometimes other substances according to the colour of the flame required. Thus, for the white star, composition oil of spike, (a preparation of Barbadoes tar, and spirit of turpentine), and camphor are employed; the camphor giving to the flame a white appearance. The blue stars owe their colour to sulphur, which is in the proportion of one to four of the meal-powder; the variegated stars have the same materials, with sulphur vivum, and camphor; and the brilliant stars, common stars, and a variety of others, we shall mention in their proper places, are all formed by the addition of sundry substances.
The variety of rains, as gold rain, silver rain, &c. are differently prepared. Besides saltpetre, meal-powder, and sulphur, gold rain contains in its composition the filings of brass, saw-dust, and pulverized glass. In this instance, the saw-dust communicates colour, while the brass and the glass are thrown out, the former partly consumed, and the latter partially fused by the intense heat. The same effect may be produced by meal-powder, saltpetre, and charcoal, or saltpetre, sulphur, antimony, brass filings, saw-dust, and pulverized glass. Here the antimony, as well as the brass, communicates the golden colour. (See antimony.) Silver rain is generally formed of saltpetre, sulphur, meal-powder, antimony, and sal prunelle, but without saw-dust; the antimony communicating silver brilliancy to the flame. It may also be formed, by employing, in given proportions, saltpetre, sulphur, and charcoal, the particular effect depending upon the proportions; or by using antimony in lieu of the charcoal, or in the place of the antimony, steel-filings. Whether antimony or steel-filings are used, the effect of their combustion is the same, forming in the one instance, an oxide of antimony, and in the other, an oxide of iron. Both gold and silver rain is employed chiefly for sky-rockets. As to the colours required, they may be formed of other substances.
The charges for water-rockets are also various. In some of which, besides the usual ingredients, (meal-powder, saltpetre, and sulphur,) sea-coal, steel-filings, saw-dust, &c. enter into their composition.
As to the different compositions, it will be sufficient to remark, that for wheels, fixed cases, sun cases, gerbes, Chinese fire, tourbillons, water balloons, water squibs, serpents, port-fires, cones, globes, air-balloon fuses, fire-pumps, and many others to be noticed hereafter, the basis of them is either gunpowder or saltpetre, and sulphur and charcoal, with or without additions. With respect to the composition of the stars of different colours, it is to be observed, that the particular colour is given by pulverized cast-iron, steel-filings, camphor, amber, antimony, perchloride of mercury, (corrosive sublimate), ivory-dust, copper, frankincense, &c. To produce tails of sparks, pitch or rosin is added. Stars which produce some sparks are usually made by using gum water in mixing the composition. The gum appears to produce a separation of the inflammable substances, and, as it is not combustible, to check, as it were, the rapidity of the combustion. In some preparations, also, isinglass or fish-glue is used in solution. This, no doubt, acts in the same manner, as well as to give firmness to the composition; but its solution is also used as a vehicle. On the same principle also, we learn the use of caustic ley, quicklime, &c. in preparing match-rope. After soaking the cord in a solution of nitre, it is afterwards dipped into ley, which is nothing more than a solution of potash rendered caustic by means of quicklime. The potash evidently checks the combustion. The formulæ for slow match, are, however, various. In the match-wood, also, prepared from the wood or bark of the linden, the wood is usually first soaked in a solution of saltpetre, and afterwards in a solution of acetate or sugar of lead, &c. For the same purpose, nitrate of copper is recommended. For stars of a yellow colour, besides gum arabic, or gum tragacanth, saltpetre, and sulphur, the addition of powdered glass, orpiment, (sulphuret of arsenic), and white amber, are occasionally made. The colour is owing to the amber and the orpiment, which have the property of communicating it to flame. We may observe, generally, that the colours produced by different compositions, is a subject of importance to the pyrotechnist. He should know the properties of each substance, and the effect of each ingredient; and, with respect to their action, be able to foretell the appearance of the flame, and other circumstances connected with the art. As a general example, we may state, that sulphur gives a blue; camphor, a white, or pale colour; saltpetre, a clear white yellow; amber, a colour inclining to yellow; muriate of ammonia, (sal ammoniac), a green; antimony, a reddish; rosin, a copper colour, and Greek pitch, a bronze, or a colour between red and yellow. In using these substances, the following remarks may be useful;—that for producing a white flame, the saltpetre should be the chief part; for blue, the sulphur; for flame inclining to red, the saltpetre should be the principal ingredient, using at the same time, antimony and pitch. (See matches of different colours, in Part ii.)
Coloured flame may be produced by various other substances, many of which are expensive, and therefore could not be employed economically. Thus, in fire-works made with hydrogen gas, or inflammable air, which have a pleasing effect, by forcing the gas, either from a bladder, oiled-silk bag, or gas-holder, through a variety of revolving jets, which are so arranged as to exhibit stars, or through pipes furnished with small apertures, &c. to resemble different standing figures—the effect may be varied by previously mixing the gas with the vapour of ether, and other substances, which communicate to the flame, particular colours, which, in a darkened room, are extremely brilliant. Cartwright's fire-works are formed in this manner. (See fire-works with inflammable air.)
Muriate of strontian, mixed with alcohol, or spirit of wine, will give a carmine-red flame. For this experiment, one part of the muriate is added to three or four parts of alcohol. Muriate of lime produces, with alcohol, an orange-coloured flame. Nitrate of copper produces an emerald-green flame. Common salt and nitre, with alcohol, give a yellow flame. (See Illuminations and Transparencies.)
In addition to the facts already stated, it may be proper to observe, that the ingredients employed to show in sparks,