Part 3
2. SULPHUR.--Sulphur is the next ingredient, in regard to importance, as being the most inflammable material we are acquainted with. It exists in three states, in all of which it is occasionally employed in fire-works; the first is that brought from the neighbourhood of volcanoes, and is called _native sulphur_, but more commonly _sulphur vivum_, though (it may be observed,) what is sold in the shops under this name is a drossy powder, the refuse left after purification. The second is that in the roll, called _roll sulphur_, or _stone brimstone_. The third is the _sublimed sulphur_, or as it is commonly called _flower of sulphur_; this when genuine is the purest, and is found to answer best for all nice and delicate articles, and from its being already in a state of powder it is by far the most convenient, as the others require to be ground or mealed previous to their being used. The first kind is the cheapest, and answers pretty well for all large and coarse articles, but as it is most frequently mixed with earthy matter and other impurities, the use of it we would not very much recommend. The second is found to be the strongest, and which is mostly used, particularly for most of the ordinary articles; but such is the desire of gain, that this article of sulphur is not suffered to pass through the hands of dealers without its quality being reduced by adulteration, which they effect by mixing with it rosin, flour, &c.; when pure it is of a bright yellow colour, dense but not too heavy, easily cracks with the heat of the hand, and the broken parts look bright and crystallized. There is another kind of _sulphur_ (though not generally known among dealers) which does not burn like the others, and what is rather singular, it emits no sulphurous smell, for being put upon the fire it melts just like common wax; this sort is found in great abundance in Iceland near Mount Hecla, and Carniola. This sulphur is commonly of a reddish colour, like that found in the straits of Heildesheim, where it is likewise of several colours, as pale yellow and green, and generally adheres to the surface of stone and rocks, from which it may be easily broken off and collected; that which is perfectly yellow of each kind is the best. That of our first description, or _sulphur vivum_, is sometimes called _quick sulphur_ from its undergoing no change by fire, since its productions by nature; and in some countries it is called _virgin sulphur_, because the women and girls in Campania frequently make a kind of paint of it, for no less delicate purpose than that of beautifying the face. Should either kind be met with in an impure state the following method may be applied for the purpose of purification.
3. _To purify Sulphur._--Melt a quantity of it in an iron pan, by which means the earthy and metallic parts will be precipitated, and then pour it into a copper-kettle, where it will form another deposit of the impure matter with which it is mixed; after keeping it for some time in a melted state, pour it into cylindric wooden moulds, for the purpose of forming it into sticks; the moulds may be about an inch in diameter; their length may be various. If the sulphur should take fire during this operation it may be quickly extinguished by covering the pan close over at the top.
4. CHARCOAL is also a considerable ingredient in our compositions, but is of a much more simple nature than that of the foregoing ones. It may generally be procured at the hardware shops, or at foundries, or it may be easily prepared, for which put a quantity of small pieces of wood, such as beech or alder, into a large earthen or iron pot, filling up the vacuities, and covering the top with sand; then placing the pot in the middle of a strong fire, and keeping it at a red heat for two or three hours, as the sand excludes the air, the wood is thus reduced to charcoal without the possibility of its being consumed; and when the pot is cold, the charcoal is to be taken out and kept for use in some very dry place. Small quantities should only be made at a time, as it is always best newly prepared.
5. 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.
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 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. The grains thus sorted have been called _iron-sand_, and have been distinguished into sand of three or four _orders_, according to their respective fineness; thus the sand that passes through the finest sieve, is called sand of the _first order_; and that which passes through the second, sand of the _second order_; and so on to the fourth, which is generally very coarse. The finest is calculated for fire-works of the smallest size, the second for pieces somewhat larger, and that of the last order, only for pieces of the largest size, such as gerbes of six or eight pounds, the composition of which being of proportionate strength to bring such large particles into a state of ignition.
As these grains are very apt to rust by keeping, they should be preserved either in close stopped bottles, well dried, or in boxes that shut close, and are lined with paper moistened in linseed oil. It sometimes happens that fire-works may be required to be kept a long time, or sent abroad; neither of which could be done with the brilliant fires, if made with filings unprepared, for this reason, that the salt-petre being of a damp nature it causes the iron to rust; the consequence of which is, that when the works are fired there will appear but very few brilliant sparks, but instead of them a number of red and drossy sparks; and besides, the charge will be so much weakened that if this were to take place in wheels, the fire would scarcely be strong enough to force them round; but to prevent such failures in the firing of them, the filings, or iron-sand, may be thus prepared:--
6. _To prepare iron-sand._--Melt in a glazed earthen pan some brimstone over a slow fire, and when melted throw in some filings, which keep stirring till they are all covered with brimstone, this must be done while it is on the fire; then take it off and stir it very quickly till cold, when it must be rolled on a board with a wooden roller, till broken as fine as corned powder, after which sift from it as much of the brimstone as possible.
_Second method._--There is another method of preserving filings so as to keep two or three months in winter, which is done by rubbing them between strong brown paper, which has been previously moistened with linseed oil. In heating the brimstone the caution given in Article 3, must be observed in the event of its catching fire.
We must observe in fine on this article, that it will be well to anticipate a little trouble in the preparation of this granulated Iron-sand, for cast-iron being of so hard a nature as not to be cut by a file, we are obliged to pulverize it, or reduce it to grains by the method we have described, which is rather difficult to perform; but when we consider what beautiful sparks this iron yields, no pains should be spared to granulate such an essential material.
We must further observe, that when these plates of iron cannot be procured, an old cast-iron pot may be employed; but especial care must be taken that its surface be perfectly free from rust and other impurities previous to its being pulverized, otherwise it will entirely destroy the effect it is intended to produce.
It is to the Chinese we are indebted for this method of rendering fire so brilliant and variegated in its colours, who discovered it long before Father d’Incarville made it known to the European countries. This sand, when it inflames, emits a light exceedingly vivid; and it is surprising to see fragments of this matter not larger than a poppy seed, form all of a sudden luminous flowers of stars, twelve and fifteen lines in diameter. These flowers are also of different forms, according to that of the inflamed grain, and even of different colours, according to the matters with which the grains are mixed. But rockets, into which this composition enters, cannot be long preserved, unless prepared as described in the early part of this article.
There are many other substances occasionally employed in the composition of fire-works, but as they can be procured at all Chemists and Druggists ready for the purpose, we consider it unnecessary to give any detail respecting them, further than enumeration. They are chiefly the following, viz. _Camphor_, which is used to improve the appearance of the fire; _Antimony_, or _Sulphuret of Antimony_, _Sal-ammoniac_, _Verdigrease_, and _Pitch_, for giving to the fire different and particular shades of colour; _Flowers of Benjamin_, or _Benzoic-acid_, for imparting to it an agreeable odour; and _Spirits of Wine_, or _Camphorated Spirits_, for mixing up the ingredients into a paste. These liquids are found to answer much better than common water, or gum-water, which is sometimes used, as they do not dissolve the salt-petre, and are therefore not so liable to produce a separation of the materials employed. _Lamp-black_ is sometimes used instead of charcoal, and is supposed to have the effect of diminishing the heat of the fire, while it does not materially lessen its brilliancy. Thence it is a considerable ingredient in what is called _cold-fire_, the seeming paradox of which we shall hereafter reconcile. For the same purpose, that of diminishing the force of the composition, _powdered glass_ and _saw-dust_ have been frequently employed; but probably these effects might be better, and with more certainty answered, by lessening the proportion of nitre.
7 OIL OF CAMPHOR.--This liquid is frequently used for the purpose of moistening the compositions; it is thus easily procured: put a small quantity of Camphor into a brass mortar, and to it add some oil of sweet almonds, sufficient to reduce it to a stiff paste, then work the mixture well together, and it will turn to a green colour, after which add a sufficient quantity of oil to liquify it for use. We must observe on the use of this liquid, that the composition into which it enters must be kept as much as possible from the air, as an exposure to it will cause it to evaporate, and thereby cause a failure in the exhibition.
8. BENZOIN.--Benzoin, or as it is vulgarly called Benjamin, is a resinous matter obtained from the tree called _Benzoin_, and is brought from different parts of the Indies, where it is found of various kinds, and of different colours; the best is that which is full of white spots and is easily broken. It is used in odoriferous fire-works, but prior to which it must be reduced to a fine powder, which may be effected by the following method:--put about three or four ounces of Benzoin grossly pounded into a deep and narrow earthen pot, and cover the pot over with a cone of thick paper, which tie closely round the edge, then place the pot over the fire and apply a moderate heat; after the interval of an hour take off the cone, and you will find some flower sticking to the under-side of it; or in the language of chemistry, the acid is sublimed and is deposited on the paper; the cone must be returned to the pot, and the operation continued till the flower appears very white and fine.
The acid which is frequently used may be obtained by digesting Benzoin in sulphuric acid, and by this it is obtained much purer and in finer crystals than by any other method.
On this article we deem it requisite to give the above information; but to the private practitioner, it will be more eligible to purchase it ready prepared.
SECTION III.
APPARATUS.
In the practical part of Pyrotechny, the constructing and due proportioning of the moulds is a very material consideration, for on these the goodness of the article depends nearly as much as on the purity of the ingredients. They consist chiefly of solid and hollow cylinders made either of wood or metal; those that are hollow are called _moulds_, and those that are solid _formers_; both are used in the construction of rockets; similar cylinders either of wood or metal are used for ramming down the composition; a machine for contracting the aperture of the cases, the operation of which is called _choaking_; another for boring them after they are filled; and a simple apparatus for grinding the materials previous to the cases being filled, as well as others of less importance, which we shall choose rather to describe as their assistance is required.
We shall begin the important Apparatus with describing those which come most immediately into use.
1. GRINDING MACHINES.--For the purpose of triturating or properly mixing the several ingredients together, various contrivances have been resorted to. 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. To obviate these dangerous probabilities a very simple contrivance has been effected; this is called the mealing table, and for that purpose has proved very speedy and effectual. It consists of a rectangular elm board, with a rim round its edge, four or five inches high, at one end of which a part of the rim is made to slide in a groove, so that after mealing the powder it may be swept clean out from the table. A representation of it may be seen at plate 1, fig. 3. Fig. 4 is a small copper shovel, generally made use of for filling and emptying the table. When about to meal a quantity of powder, observe not to put too much on the table at once; but when you have put on a moderate portion, take the muller (fig. 5,) and rub it till all the grains are well broken; then sift it in a lawn sieve, that has a receiver and top to it, such as is generally used by the apothecaries, and that which does not pass through the sieve must be returned to the table, and with an additional quantity ground over again. Sulphur and charcoal may be ground in the same manner, only these being much harder than powder the muller must be of ebony, or any other hard wood, else the ingredients would stick in the grain of the elm, and be very difficult to grind. As sulphur is apt to stick and clod to the table, it will be found best to have one for that purpose, as they are easily procured; this will be but little trouble, and more than compensated by your sulphur being always kept clean and well ground.
The following is another method for the above purpose, which some consider equally effective. This is a mortar made of hard wood, shaped like that of the druggists, with the bottom rounded within, and having a wooden lid fitting close on the top, and in the centre a hole just large enough to admit easily the stalk of the pestle, to the lower end of which is connected a piece of marble terminating in a spherical surface. With this apparatus gunpowder may be safely ground to meal, or its ingredients mixed by the continued motion of the pestle in the hole of the lid.
2. _Method of mixing the Ingredients._--Connected with that of grinding is the operation of mixing the ingredients, and which is considered a principal part of the business of Pyrotechny; and indeed many articles depend as much on the well mixing as on the proportion of their composition; therefore great care should be taken in this part of the work, and particularly so in the composition of sky-rockets. When you have about four or five pounds of ingredients duly prepared for mixing, (which is a sufficient quantity to mix at one time,) first put them together in some vessel convenient for the purpose, then work them about with your hands, till their various natures are pretty well incorporated; after which put them into your lawn sieve with the receiver and top to it, and sift it into some other clean vessel, and if any remains that will not pass through the sieve, grind it again till fine enough; and if it be suffered to pass twice through the sieve it will be more than the trouble the better. For rockets and all fixed works, from which the fire is to play regular, the ingredients must be prepared as above; and we may observe here, that all compositions which contain steel or iron filings must be mixed or shifted with the copper shovel, for the hands are apt to impart a moisture, which is injurious to their nature. Nor will any works which have iron or steel in their charge keep long in damp weather without being properly prepared, as was directed in the preceding Section.
There are several other moulds and apparatus made use of, but as most of them are used in the making of rockets, and some few other articles, and are so immediately connected with the practice thereof, we think their use and application will be better understood when we come to treat of that article in the next Section, rather than by entering their descriptions in this place.
SECTION IV.
DIVISION OF FIRE-WORKS.
Fire-works are generally divided into two classes, those which compose the first are chiefly _squibs_, _serpents_, _crackers_, _sparks_, _marroons_, _saucipons_, _pin-wheels_, _leaders_, _gerbes_, or _roman candles_, and (when without any appendages) _rockets_; these by their requiring but little dexterity in the preparation are called simple, or more properly single fire-works, and are said to be of the first class. Others which are of more difficult constructions, are called compound or complex fire-works, and are said to be of the second class. These consist of _suns_, _moons_, _stars_, _wheels_, _globes_, _balloons_, _batteries_, _flower-pots_, _fire-pumps_, _pyramids_, _&c._; these are generally composed of some of the single pieces, as gerbes, serpents, marroons, saucipons, &c. properly arranged on suitable frames, according to the taste of the operator, and connected with each other by long pipes filled with inflammable composition called leaders, and fired by means of _quick-matches_ or _port-fires_, and very frequently by common touch-paper. We shall begin our descriptions and instructions, with those of the simple or single kind, which will lead us progressively to those which are more complex, the order we purposed pursuing at the commencement of our Work.
In the subsequent directions we shall have frequent occasion to mention pipes of communication, commonly called _leaders_, by which the several parts of a compound work are connected with each other; and several other articles of less importance, as touch-paper, quick-match, port-fires, &c.
1. TOUCH-PAPER.--This is a paper impregnated with a solution of salt-petre, by which it acquires the property of burning slowly away without flame, and yet with sufficient strength to communicate its fire to meal powder, with which it comes in contact. It is prepared in the following manner:--
2. _To Make Touch-Paper._--Dissolve a quantity of salt-petre in vinegar or any other acid, more or less of the salt-petre according as you would have your paper to burn slow or fast; then dip into this solution some thin blue paper, let it be well saturated, then take it out, and dry it for use. If, on trial, it is not found to burn properly, or if it blazes on being set on fire, it is an indication that your solution is too weak; you must therefore strengthen it by adding more of the nitre, and the paper must be passed through again. On the application of this paper to fire-works, two modes are in use:--For small articles, or such as are _choaked_ (to be hereafter explained) tie a piece round the orifice with thread or fine twine, leaving enough of the paper at the end to form a small tube, in which is put some mealed gunpowder, and the paper is then twisted over it, and ready for firing.
For larger articles, as Rockets, Roman Candles, &c. the paper, instead of being tied should be pasted round the orifice with thin flower paste; but care must be taken that the paste does not extend beyond the end of the case, for this would prevent the fire from communicating with the composition, and the piece would consequently fail in the going off.
3. QUICK-MATCH.--The purpose of the Quick-match is similar to that of touch-paper, but chiefly used to form the inside of leaders; it is generally made of cotton-wick, (such as is usually made use of in the manufacture of candles) impregnated with nitre. It is made of several sizes, from one to six threads, as is most suited to the pipes, or articles for which it is designed. The pipes must be sufficiently large to receive the match easily, as its quality will be much diminished by its breaking. The following is the best method of making this match:--Having distributed the cottons into the number of threads requisite for your purpose, coil it very lightly into a flat bottomed copper or earthen pan, then pour in a part of the salt-petre and liquor, and boil them together about twenty minutes, after which coil it again into another pan and put to it the remainder of the liquor, then put in some meal powder, and well mix it with the liquid; after which place the pan beneath the wooden frame (fig. 12) and tying one end of the cotton to one side of the frame, then by one hand by means of the handle (A) turn the frame round while you let the cotton pass through the other, holding it very lightly, and at the same time keeping your hand full of the wet powder; if the powder is too wet to stick to the cotton put more in the pan, so as to keep a supply until the match is all wound up; you may wind it as close on the frame as you please, providing it do not stick together; when the frame is full take it off the joints and sift dry meal powder on both sides the match, till it appears quite covered, afterwards hang it in some warm place to dry, which, if it be in summer, will be effected in a few days, but if it be in winter it will be a fortnight before it is fit for use; when it is perfectly dry, cut it along the outside of one of the side-pieces of the frames, and tie it up in skains for use.
The proper ingredients for the Match are, cotton, one pound twelve ounces, salt-petre, one pound, spirits of wine two quarts, water three quarts, isinglass three gills, and meal powder ten pounds; or half the quantity may be prepared by taking the ingredients in the same proportion. Four ounces of isinglass should be dissolved in about 3 pints of water.