G. W. Mortimer

“ A common iron mortar, such as is used by druggists and apothecaries, is found to answer very well for grinding or pounding the brimstone, charcoal, salt-petre, &c. separately; and apothecary’s close sieves, fitted with wire-cloth, are the best possible implements for obtaining the fire powder; but when corn gunpowder is to be mealed, or the various ingredients are to be mixed together, such mortars cannot be used, as the heat generated by the continued action of the pestle might inflame the mixture, and thereby place the life of the operator in imminent danger. ”

“ If about an inch of metal be made fast to one extremity of the half tube of the diameter of the rod or former, it will supersede the necessity of a foot, and be much more convenient; but the part of the former as we may term it, must be made very fast to the tube, or it will easily be detached by the ramming of the cases. The composition for filling these cases generally consists of salt-petre, sulphur, and mealed powder, in various proportions, according to the intended strength of the fire, though salt-petre is generally in the greatest proportions. ”

“ To those who manufacture fire-works for sale it is certainly the most expeditious method to ram them solid, and with the machine to bore or pierce them afterwards; but to those who make Rockets for their own private recreation, it is by far the most eligible to load them over a piercer, for by the other method it will require a very expensive apparatus, [9] and at first more skill to use it than what the Tyro will possess, and at last he will never be certain that he has made a good article. ”

“ Avoid as much as possible placing the leaders too near or one across the other, so as to touch, as it may happen that the flash of one will fire the other, and thereby destroy the beauty of your arrangements. ”

“ Rockets consist of strong paper cylinders, which being filled with the proper composition rammed hard, and fire being applied to their apertures they are caused to ascend into the air, or in any required directions; they have generally a head fixed to them [83] containing corn powder, sparks, and many other decorations, which, when the body of the Rocket is consumed, take fire, burst in the air, and produce a most beautiful appearance; these are called Sky-rockets. ”

“ If the barrels of some small tubes, or quills, filled with the composition of Flying Rockets, be placed on a large one, they will, when fire is communicated to them, represent a beautiful shower of fire.
If a number of small serpents be attached to the Rocket with a piece of pack-thread, by the ends that do not catch fire; and if the pack-thread be suffered to hang down two or three inches between every two, this arrangement, when properly managed, will produce a variety of agreeable and amusing figures. ”

“ Provide two light wheels, in diameter from two to three or four feet: they must be fixed firmly to a square axle-tree, or in such manner that they cannot revolve on it; the axle may be about three feet in length. Then on the middle of this axle is to be firmly fixed a fire-wheel, which must be so much less in diameter, that when the cases are attached to it, it may be quite clear of the ground; care must be taken that this middle wheel be fixed at right-angles from the axle, or it will not keep in a straight direction when set in motion. ”

“ Rockets have ever held the first place among single fire-works since the invention of the art; and to which they are justly entitled, both for the pleasing appearance they produce when fired by themselves, and the extensive application of them to increase the beauty of the other exhibitions. ”

“ Construct a hollow wooden globe of any [162] dimensions at pleasure; it must be very round, both internal and external; its thickness must be equal to about the ninth part of its diameter. In this globe insert a small wooden cylinder, (A fig. 28.) in breadth equal about one-fifth diameter of the globe, its thickness about half that of ditto: of the same size and opposite to this cylinder must be another aperture. It is through this latter aperture that fire is communicated to the globe, when it has been filled with the proper composition through the lower end of it ”

“ Accordingly we find that if the composition of the Rocket be very weak, so as not to give an impulse greater than the weight of the Rocket and stick, it does not rise at all; or if the composition be slow, so that a small part of it only kindles at first, the Rocket will not rise.
To this we shall add the late Doctor Hutton’s philosophy, on the ascent of Rockets; who says, that at the moment when the powder begins to inflame, its expansion produces a torrent of elastic fluid, which acts in every direction ”

“ HONORARY ROCKETS.
Take about a pound Rocket of our first description, such as is represented in fig. 23; then on the case, close to the top of the rod, tie on, in a transverse direction, a two-ounce case, which should be filled with a strong charge, and choaked quite close at both ends; then towards each end, and in the reverse sides, bore a hole of moderate size, and from each carry a leader into the top of the large Rocket. When the Rocket attains its greatest height, it communicates fire to the cross one at top ”

“ The mortars should be made of paste-board, [147] wound two or three times round a cylinder, about four inches diameter, and well secured by glue, by which means their bottoms and tops are fixed to them.
The spur-fire, which is the chief ornament of these pieces, is prepared as follows:—It has been said that excellence can never be obtained, without overcoming commensurate difficulties; this is certainly verified in the preparation of this composition; for nothing can exceed the difficulty and trouble in preparing it, and nothing can exceed the beauty of its appearance when properly prepared. ”

“ Hutton seems to differ from the opinion of M. de la Hire, in regard to the expansion of inflamed gunpowder. Is it, he observes, occasioned by the air interposed between its grains, or by the aqueous fluid which enters into the composition of the nitre? We doubt much (continues he) whether it be the air, as its expansibility does not seem sufficient to explain the phenomenon; but we know that water, when converted into vapour by the contact of heat, occupies a space 14,000 times greater than its original bulk, and that its force is very considerable. ”

“ A pretty exhibition may be produced by placing a number of spur-fires round a transparent pyramid of paper, and fired in a room, or in the open air. In all cases, and every variety of exhibition, this fire is very beautiful, and will always repay the labour of preparation. ”

“ Iron-filings, (for this Steel-dust is nothing more than pure iron reduced into small particles by filing or some other method,) when free from rust, and not mixed with any impurities, answer very well; but fire-work [36] makers generally prefer cast-iron reduced to powder, by beating thin plates of it on a cast-iron anvil with a heavy hammer, and sifting the broken particles through sieves of brass or iron wire, of different degrees of fineness, so as to separate the particles into grains of various sizes, according to the magnitude of the pieces. ”

“ Sparks.—It is only as it regards magnitude that Sparks differ from stars above described, they being generally made of very small size, and consequently of short duration in their exhibition. The method of preparing them is as follows: put into an earthen vessel one ounce of mealed gunpowder, three ounces of powdered salt-petre, and four ounces of camphor, reduced to powder by rubbing it in a mortar with a small quantity of spirit of wine; pour over this mixture some weak gum-water, in which some gum-adraganth has been dissolved, till the composition is brought to a state of thin paste ”

“ There are only three ingredients that enter into the composition of Gunpowder; these are Salt-petre, Sulphur, and Charcoal. The first is a combination of Nitric Acid [1] and Potash, [2] and is better known in modern chemistry by the name of Nitrate of Potash. The second is a substance very well known, from the inflammable properties it possesses; it is found alone, or combined with other bodies, in various situations; in volcanic productions it is found almost in its last degree of purity: it is found also, in the state of sulphuric acid ”

“ Steel-dust is another important ingredient in fire-works, for being mixed with mealed powder or some other composition, and the mixture inflamed in a proper tube, or case, the jet of fire produces a most brilliant appearance by the sparks arising from the ignition of the iron in the oxygen gas of the nitre. ”

“ During the time the Rocket burns, the common centre of gravity is shifting and getting downwards, and still faster and lower as the stick is lighter; so that it sometimes begins to tumble before it is quite burnt out: but when the stick is too heavy, the common centre of gravity will not get so low, but that of the Rocket will rise straight, though not so fast.
From the experiments of Mr. Robins, and other Gentlemen, it was found that the Rockets of two, three, or four inches diameter, rise the highest ”

“ Rockets of large dimensions, whose cases are made of a strong material, properly prepared, may be conveniently rammed without being placed in a cylinder, which will be an advantage, as so many moulds will not be required. But for this method of ramming we must be prepared with some brass or iron nipples, of the size proportionate to the Rocket, which should be made to screw into one part of the driving block ”

“ The wheel will be much improved, if instead of a common case in the middle, you fix a case of Chinese-fire, in length sufficient to burn as long as three cases on the wheel. In all the cases, (except the first one,) on each wheel should be driven a ladle-full or two of slow-fire, in any part of the case: in the end of one or two alternate cases you may also ram a ladle-full of dead-fire composition, which must be very lightly rammed; many other changes in the appearance may be produced by alternately ramming in composition of different orders. ”

“ Jebb, in his preface to the above-cited [14] work, describes two kinds of fire-works; one for flying, inclosed in a case or cartouche, made long and slender, and filled with the composition closely rammed, like our modern rocket, and the other thick and short, strongly tied at both ends, and half filled, resembling our cracker; and the composition which he prescribes for both, is two pounds of charcoal, one pound of sulphur, and six pounds of salt-petre, well powdered and mixed together in a stone mortar. ”

“ The central block must be pierced in the middle for the purpose of receiving a strong pin, or a small piece of wire, by which the wheel may be attached to a post or any other convenient object, or the pin or wire being inserted into the pith of an hazel stick, the wheel without any danger may be let off in the hand; when the mouth of the last round is primed and capped with touch-paper, on its being lighted, the impulse of the flame against the air forces back the ignited part of the wheel, which continues to revolve till the whole of the composition is consumed. ”

“ When charcoal is burnt, its carbon unites with the oxygen of the air, and so much heat as to give it a gaseous form, and constitutes carbonic acid gas, or fixed air. The same gas is also obtained by the combustion of the diamond, proving that this precious and costly article is carbon or charcoal, in a very indurated state, and assuming a determinate form. ”

“ The Rocket may be set over a hole in a board, and fired from the under side; or the four wings may rest on four iron pins, six or eight inches in length, drove into a board at suitable distances from each other, and the Rocket fired from between them.
Though the greatest care be employed in the exhibition of Rockets after this manner, still their ascent is by far less certain than when a rod is used; therefore the Tyro must [125] not be disappointed if he chance to fail of success. ”

“ To the large cartridge, or head, of about a two pound Rocket, place round several small ones of about two or three ounces, the rods of which must be made quite fast to the head, and parallel to the rod of the larger; then, if these be set on fire while the large one is ascending, they will represent in a very pleasing manner, a tree, the trunk of [123] which will be the large Rocket, and the smaller ones the branches.
If, by means of leaders, the small Rockets are caused to take fire when the large one is about half burned in the air, they will represent the form of a comet ”

“ In the composition care must be taken that the ingredients are well mixed, and previous to its being made up, it must be wetted with the following liquid sufficient to convert it into paste; spirit of wine one quart, in which dissolve one fourth of an ounce of Isinglass. Too much of the composition must not be prepared at once, one pound will be sufficient for an ordinary number of Stars, for if a greater quantity is wetted the spirit will be liable to evaporate, and leave the composition dry and unfit for the purpose, before it can be all rolled up. ”