PYROTECHNY, from nug, fire, and riχνη, art. The usual modern meaning of the word is the art of making fireworks, and of disposing them to the best advantage when exhibited on occasions of rejoicing, or in theatres, gardens, and other places. A moment’s consideration will show how very comprehensive a term pyrotechny may become if extended to all operations in which the skilful management of fire is required. It was anciently confined chiefly to alchemy, or incipient chemistry.^[1. See Davidson’s Philosορhia Pijroicehnica, &c. 1635; and G. Starkey’s Pyrotechny Asserted and Illustrated, &c. 1658. ]

Under the term pyrotechny we may properly enough include the making of the different sorts of gunpowder, and the preparation of all those combustible or detonating materials and projectiles used in war; but then it should be distinguished by the adjunct military. Military pyrotechny will then serve only to indicate a portion of one of the [7:18:757] most deplorable arts ever invented, that is, the art of war. The miserable necessity of this art is, however, a matter of daily experience in the present state of human nature and unsocial relations; also the unhappy and slavish condition of all nations which are not able, by skill in this diabolical art, to resist effectually the aggressions of their invaders.^[2. See the articles Guskery, Guspotdek, Projectiles, Was. ]

We do not mean to give an account of the various substances, mixtures, and manipulations necessary in the construction of different fire-works; but, for the reader’s amusement and instruction, we shall mention a few things which are not generally known, and then conclude with the titles of a few works upon pyrotechny.

The combinations of the different substances employed in the pyrotechny connected with fire-works ought to be guided by a chemical knowledge of these substances. The want of this knowledge causes most of our fire-workers to compound ineffective mixtures, and to follow old and absurd recipes. Great skill in pyrotechny, in its more general sense, was possessed by the Chinese long before the art was known in Europe. The invention of gunpowder seems to be due to them, and perhaps also the invention of fire-works. All those persons we ever conversed with who had been in China, concurred in assuring us that the Chinese fire-works are at this day quite unrivalled in variety, splendour, and beauty. In the account of Lord Macartney’s Embassy to China there is an amusing passage describing the contempt of the Chinese for the best English fire-works that were exhibited to them, and the astonishment of the embassy on witnessing the superb display of fire-works given by the Chinese in return. The most imposing exhibitions of European fire-works used to be those that took place annually at Rome, during certain holidays, on the ramparts of the Castle of St Angelo.

We shall now give a very few notices of practical pyrotech ny.

Lightnings —The fine seeds of the lycopodium clavatum, or common club-moss, are extremely inflammable, and arc used in theatres to imitate a vivid flash of lightning, by blowing them from a tube, &c. through the flame of a lamp, &c. These seeds are also used in the composition of some fire-works.

Red Fire. — The nitrate of strontia is the chief ingredient in the composition. A beautiful purplish flame is produced by a composition containing chlorate of strontia. To aid in reddening the flame of the former composition, a little lamp-black of the finest quality is generally used; for a red jet of fire from a paper-case formed like that of a serpent, or of a Roman candle, &c., fifteen parts of pulverized gunpowder and four parts of dry nitrate of strontia; a slow and bright-red fire, forty parts of nitrate of strontia, thirteen of pulverized sulphur, five of chlorate of potash, and four of sulphuret of antimony. In this last mixture, to avoid the danger of premature combustion, the chlorate of potash must not be ground in a mortar with the other ingredients, but ground separately, and afterwards mixed with them by shaking and stirring upon a sheet of paper.

Green Fire. — Seventy -seven parts of nitrate of barytes, thirteen of pulverized sulphur, five of chlorate of potash, three of charcoal in powder, and two of pure arsenic. The same precautions to be taken as before with regard to the chlorate of potash. The effect of this composition, when burned on the stage of a theatre, is to give a cadaverous and unearthly aspect to the actors. It occurred to us many years ago, that an extension of some of the effects of De Loutherbourg’s Fidophusikon might be easily and effectively adapted to the stage. Where the ioot-lights are, or else above the proscenium or front of the stage, an apparatus might be contrived to throw variously-coloured lights upon the actors and the scenery in the representation of magical incantations, supernatural appearances, &c. The disposition and reflection of these variously-coloured lights might be diversified in such a manner as to produce the most singular contrasts and unexpected effects.

Brilliant and sparkling jets of Fire—These are produced from compositions rammed into paper-cases of various sizes. One of these compositions may consist of eighteen parts of pnlverized gunpowder, five of bright steelfilings, and two of saltpetre; another of sixteen parts of pulverized gunpowder, seven of steel-filings, one of saltpetre, and one of sulphur.

Sparks.— The composition for these is mixed with pure alcohol. Small pellets of cotton are steeped in this mixture, and dried, after rolling them in pulverized gunpowder.

Stars — Very brilliant stars, such as we see issue froni sky-rockets, Roman candles, &c., may be made from a composition of one part of alcohol, one of antimony in powder, two of pounded crystal, one of gum-arabic, two of pulverized gunpowder, fifteen of saltpetre, six of sulphur, and two of zinc-filings. The composition for these and other stars is made into a stiff paste with alcohol, and then cut into small cylindrical or square pieces, which are rolled in pulverized gunpowder, and dried in the shade.

Brilliant Chinese Fire —Four parts of charcoal, five of pounded cast iron, eight of pulverized gunpowder, six of saltpetre, six of sulphur; or three parts of pounded cast iron, eight of pulverized gunpowder, two of saltpetre, and one of sulphur; all rammed into paper-cases or other cases.

Jasmine Flowers — This beautiíül fire is generally seen in the vertical fire-wheels, &c. When the composition is well made, the sparks drop down somewhat like burning flowers of the jasmine. Its excellence depends chiefly on the use, in the composition, of bright filings or raspings from the steel-springs of clocks or watches, carefully deprived of all the finer dust that may be amongst them. The minute shavings of steel, procured from turners in metal, may also be used. Compositions for this kind of fire, six parts of steel-filings or shavings, sixteen of pulverized gunpowder, one of saltpetre, one of sulphur; or five parts of same filings, &c., sixteen of pulverized gunpowder, one of saltpetre, one of sulphur; or four parts of filings, twenty of pulverized gunpowder, one of saltpetre, one of sulphur, and four of zinc-tilings or raspings, or pounded zinc rendered pulverizable by being heated to about 205 of the centigrade scale. The compositions for the Chinese fire and the jasmine flowers arc to be mixed up in the same manner. The sulphur, the pounded cast iron, or the steelfilings, are mixed with the addition of a little pure alcohol, and then the other ingredients are added. It must be observed, that the size of the particles of pounded cast iron or of steel-filings should be proportioned to the size of the cases that are to be filled with the composition; the smallest filings, &c. being used for the smallest cases.

Bengal Lights The common ones are made of one part of antimony, five of saltpetre, and two of sulphur; the sparkling ones, of one part of antimony, two of fulminating composition (of fulminating mercury and gunpowder), four of saltpetre, and four of sulphur; or one, two, five, two parts of the same ingredients in their order; or one, two, six, one parts of the same in their order. Vases are filled with these compositions, a light gunpowder dust sprinkled over the top, and the whole closed up by a piece of paper pierced with some holes from which pieces of quick-match project. These lights may be made of any size. They sometimes weigh upwards of 200 pounds.
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It is necessary to warn the reader that fulminating mercury requires great caution in handling it; and, as it is so apt to explode, it had better be left out of the composition for these lights, or any other fire-works. Indeed the pyrotechnist has need to exercise the greatest possible caution in all his operations. For instance, it may, in ignorance, be imagined that no harm can happen from pounding gunpowder in a mortar along with iron or steel-filings, &c. and yet the most serious accidents may result from manipulations of this kind incautiously conducted.

One of the most formidable pyrotechnical inventions is the Congreve rocket. We have conversed with some officers who served in the war against the Burmese, and they described the effect of these rockets as appaling, not only to the Burmese, but even to the stout-hearted Britons who fired them off.

Without entering into any very minute description of the process of making such popular fire-works as the common sky-rocket, the Roman candle, &c. we shall content ourselves with a brief account of the general construction of these two. The common sky-rocket consists of a strong paper or thin pasteboard case, the lower end of which, where the cotton quick-match is inserted, is drawn so close by means of a cord as to leave only a circular opening of about one third of the interior diameter of the case. This is technically called choking the case. The case, when dried after pasting, is placed in a hollow cylinder of wood, into which it fits. This mould is furnished with a moveable bottom having a central nipple and a tapering spike of iron, which last, entering the aperture at the lower end of the case, rises within it nearly to the top. The space left round this spike is filled gradually, and by repeated blows from a mallet upon a hollow rammer, with a composition of pulverized gunpowder, saltpetre, and charcoal, or of sixteen parts of saltpetre, twelve of elm charcoal, and four of purified flour of sulphur. The rammer, which fits the inner diameter of the case, and to which the mallet is applied, has in its centre a deep hollow adapted to the iron spike before mentioned. The composition which forms the charge of the case must be put in by small quantities at a time, and driven down compactly by regulated blows of the mallet upon the rammer. The filling of the case in this manner requires skill and experience, because if the charge is not uniformly compacted in the case, the rocket will not rise evenly and regularly. When the charge has been driven a little higher than the top of the spike, a round piece of doubled paper* is put in; and upon •this one half of the inner paper of the remainder of the case is folded down and rammed firmly, so as to close the case. This plug is then pierced with a few holes, and above it are placed, along with some of the composition, or with some gunpowder, the stars, sparks, &c. that are intended to appear when the rocket has reached its highest ascent. The top of the case is then covered in, and fitted with a paper cone. In signal-rockets, that are intended to end with a report without stars, &c. the round piece of double paper before mentioned is pierced with a hole in the centre, and a little gunpowder is pressed firmly in above it, but without crushing the grains. The top of the case is then choked close, and the paper cone fitted on. In some other rockets that contain what are called decorations, that is, stars, sparks, serpents, crackers, &c., these are placed with meal-powder in a wider cylindrical case, which is fitted to the top of the case containing the charge. These rockets are also terminated by a conical cap. We may remark, that in our common rockets the conical cap is not sufficiently stiff to maintain its form invariably, and so to aid in the regular ascent of the rocket. The balance-stick has next to be fastened to the rocket. The length, thick-íiess, and weight of this stick, require calculation to suit it to the dimensions and weight of the case. On the Continent, rockets have been made to ascend without sticks by means of a triangle of pasteboard passing round the case, or by means of three pasteboard wings glued to the case. Each of these wings forms an isosceles triangle, in height six interior diameters of the rocket-case, and a little more than two of these diameters at the base. Each of these wings must be glued on quite parallel to the axis of the case, otherwise the flight of the rocket will be irregular. A short stick with similar wings has also been employed for rocket-cases. It is stated that all these winged rockets rose beautifully, even in a violent wind and bad weather; but some allowance must surely be made for the lateral action upon them of a strong wind.

The Roman candle consists of a strong case of paper or of thin pasteboard, which is completely closed at the lower end. It is generally charged with the same composition as sky-rocket cases, alternating with gunpowder and stars, as follows: First a small quantity of composition is placed at the bottom of the case, and rammed down compactly by a rammer and mallet; next a small quantity of gunpowder, and above that a star without any ramming, but a gentle push to secure the contact of the star with the gunpowder; then a quantity of the composition, which is rammed down as before; next a little more gunpowder and a star, and then more composition rammed down; and so on till the case is filled. The case is then closed by a piece of papermatch pasted round the outside, and twisted to a point at the top. The charges of Roman candles might be diversified by variously-coloured fires and stars, &c.

The reader may consult the works of which the titles are subjoined. Essai sur les Feux d' Artifice pour le Spectacle et pour la Guerre, Paris, 1750; Manuel de l' Artificier, Paris, 1757; EArt de faire à peu de frais les Feux d’Artifice, Paris, 1828; Manuel de VArtificier, par A. D. Ver-gnaud, Paris, 1828. (g. f. g.)