CHAPTER IX.
OF PARTICULAR COMPOSITIONS.
_Sec. I. Of Fire-Jets, or Fire-Spouts._
Fire-jets are produced by certain compositions, which are employed in cases, and are charged solid. They are formed and used according to taste or fancy.
The jets are made with a caliber of from one-third of an inch, to one inch and one-third, in interior diameter. They are seven or eight exterior diameters in length, and are charged in the usual manner with the composition, hereafter mentioned, driving each charge with twenty blows with a small mallet. The first charge must be the common fire composition.
Some of the compositions in the following table have already been mentioned, when treating of certain fire-works; but we deem it of importance to notice them in a connected manner, so that we may have the formulæ in one view.
Fire-jets, it must be remembered, are calculated as well for turning, as for fixed pieces.
_Common Fire for calibers of one-third of an inch._
Meal-powder, 16 oz. Charcoal, 3 --
_Common Fire for calibers of five-twelfths to half an inch._
Meal-powder, 16 oz. Charcoal, 3 -- 4 dr.
_Common fire for calibers above half an inch._
Meal-powder, 16 oz. Charcoal, 4 --
_Brilliant fire for ordinary calibers._
Meal-powder, 16 oz. Filings of iron, 4 --
_Another, more beautiful._
Meal powder, 16 oz. Filings of steel, 4 --
_Another, more brilliant, for any caliber._
Meal powder, 18 oz. Saltpetre, 2 -- Filings of steel, 5 --
_Another, very brilliant, for two-thirds of an inch caliber, and above._
Meal powder, 16 oz. Saltpetre, 1 -- Sulphur, 1 -- Filings of steel, 7 --
_Brilliant fire, more clear, for any caliber._
Meal powder, 16 oz. Filings of needles, or of needle steel, 3 --
_Silver-rain for calibers above two-thirds of an inch._
Meal powder, 16 oz. Saltpetre, 1 -- Sulphur, 1 -- Filings of steel, fine, 4 -- 4 dr.
_Grand jessamine, for any caliber._
Meal powder, 16 oz. Saltpetre 1 -- Sulphur, 1 -- Filings of spring steel, 6 --
_Small jessamine, idem._
Meal powder, 16 oz. Saltpetre, 1 -- Sulphur, 1 -- Filings of steel, the best, 5 --
_White fire, idem._
Meal powder, 16 oz. Saltpetre, 8 -- Sulphur, 2 --
_White fire, idem._
Meal powder, 16 oz. Sulphur, 3 --
_Blue fire, for parasols and cascades._
Meal powder, 8 oz. Saltpetre, 4 -- Sulphur, 6 -- Zinc, 6 --
_Another blue fire, for calibers of half an inch, and upwards._
Saltpetre, 8 oz. Meal powder, 4 -- Sulphur, 4 -- Zinc, 17 --
The cases charged with this composition are only employed for furnishing the centre of some pieces, the movement of which depends on other cases; for these, having no force, would not move the piece.
_Blue Fire, for any caliber._
Meal powder, 16 oz. Saltpetre, 2 -- Sulphur, 8 --
_Radiant Fire, idem._
Meal powder, 16 oz. Filings of pins, (_d'epingles_) 3 --
_Green Fire, idem._
Meal powder, 16 oz. Filings of copper, 3 -- 2 dr.
_Aurora Fire, idem._
Meal powder, 16 oz. Gold powder, (_Poudre d'or_) 3 --
_For Italian roses or fixed stars._
Meal powder, 2 oz. Saltpetre, 4 -- Sulphur, 1 --
_Another, for the same._
Meal-powder, 12 oz. Saltpetre, 16 -- Sulphur, 10 -- Antimony, 1 --
The jets of fire, which are various according to the composition employed, may appear under several forms, sometimes in one and sometimes in another; and hence they may put on an asteroid appearance, or that of a fountain, or water spout, or the form of rain. The effect, however, is very elegant; and, in conjunction with other species of fire-works, cannot fail to change the general appearance, by modifying the whole, or rendering it more various.
These compositions are generally used in the manner before mentioned, in cases of different sizes; but they may, under particular circumstances, be employed otherwise. In fact, the _forms_ which may be given to the flame of gunpowder, or the substances which compose it, either by increasing or retarding its combustion, or changing the appearance of the flame, and giving it the form of jets, stars, rain, &c. are so numerous, that it furnishes alone an important branch of Pyrotechny. These effects will be detailed, when we treat of the formation of compound works.
_Sec. II. Of Priming and Whitening Cases, and Remarks concerning Spunk and Touch Paper._
When the cases are charged, we pierce them with a small awl, or make a hole with a gimblet in the end, if it should be stopped with clay, or _probe_ them with a drill, as fire-workers call it, in the hole which had been filled, in which we put some more of the composition. This precaution is considered necessary, in order that the earth should not cover internally the hole of the piercer. A piece of match is then introduced, which extends on the outside, and is secured there with a plug of wood.
Brown paper, made either of linen or cotton, but not of woollen cloth, when soaked in a concentrated solution of saltpetre, is, we have said, rendered very combustible, and will convey fire for small works with much facility. It is this paper, called touch, or more properly match, paper, that is used for capping, &c. Paper of this kind may sometimes be used, as for _crackers_, _serpents_, &c. Cotton quick-match, however, is used more generally; and, for large works, when employed as a leader, it is usually confined in a proper tube, the better to preserve it entire, and to keep it dry. Spunk, made by soaking certain species of fungus in a solution of saltpetre, takes fire very readily by the least spark, and, therefore, is used for collecting and preserving the fire from flint and steel. This spunk, when well made, and particularly of the proper kind of fungus, may be cut into slips, and employed advantageously in some fire-works. In all cases, however, the object is the same, to communicate fire with facility to the powder, or composition; and this object may be attained by all those methods, which we have had occasion frequently to mention. See _Pyrotechnical Sponge_.
To _whiten_ cases is an operation, which merely consists in covering them with paper, and is performed in the following manner. We procure as many half-sheets of paper as we have cases, and put them on a table one upon another. We paste the paper, and roll each case in one of these sheets, which is named the covering. The paper is cut in such a manner, that it passes over the end of each case an inch and a half. There is no particular use in this covering, the case being made sufficiently strong without it; it makes, however, a handsome finish. In the Chinese fire-works, their cases are covered with different coloured papers, and frequently ornamented with gilding. In all that I have seen, with some of which I have made experiments, the match of communication is nothing more than twisted match-paper. The figures are made of paper, painted, and ornamented in the same way; some resembling animals, &c. but on a small scale. The leaders are fixed in the usual manner, and the works are fired in the same way. Tourbillons, serpents, and crackers are chiefly the kind which we have seen.
_Sec. III. Of Chinese Fire._
The composition for producing this fire, as it is peculiar, and therefore distinct from all others, was invented by the Chinese, and hence bears that name. The substance, which produces the peculiar effect is cast or crude iron. See _Iron_.
It was the brilliant light, produced when iron filings are thrown into the fire, that gave rise to an improvement in the fire of rockets, rendering it much more beautiful, than when gunpowder, or the substances of which it is composed, are alone employed. The Chinese have long been in possession of a method of rendering fire brilliant, and variegated in its colours. Cast-iron, reduced to a powder more or less fine, is called iron-sand, because it answers to the name given to it by the Chinese. They use old iron pots, which they pulverize, till the grains are not larger than radish seed; and these they separate into sizes or numbers, for particular purposes.
It should be observed, that rockets, into the composition of which, iron-filings and iron-sand enter, cannot be long preserved, owing to the change which the iron undergoes in consequence of moisture.
It may be proper to introduce here two tables, which exhibit the proportions of the different ingredients for rockets of this kind from 12 to 33 lbs.
_For Red Chinese Fire._
-----------+------------+----------+-----------+------------------ Calibers. | Saltpetre. | Sulphur. | Charcoal. | Pulv. cast iron. | | | | No. 1. -----------+------------+----------+-----------+------------------ lbs. | lbs. | oz. | oz. | oz. dr. 12 to 15 | 1 | 3 | 4 | 7 0 18 -- 21 | 1 | 3 | 5 | 7 8 24 -- 36 | 1 | 4 | 6 | 8 0 -----------+------------+----------+-----------+------------------
_For White Chinese Fire._
-----------+------------+--------------+-----------+----------------- Calibers. | Saltpetre. | Meal-powder. | Charcoal. | Pulv. cast iron. | | | | No. 2. -----------+------------+--------------+-----------+----------------- lbs. | lbs. | oz. | oz. dr. | oz. dr. 12 to 15 | 1 | 12 | 7 8 | 11 0 18 -- 21 | 1 | 11 | 8 0 | 11 8 24 -- 36 | 1 | 11 | 8 8 | 12 0 -----------+------------+--------------+-----------+-----------------
These substances are incorporated together in the manner already stated.
The cast-iron, we observed, is reduced to a fine powder, or rather _sand_, as the French fire-workers call it, and is then passed through a sieve. For the method of reducing it to powder, consult the article on _Iron_. That the brilliancy of the fire is owing to the iron in its crude state, without being converted into soft or malleable iron, a process which carries off a large quantity of carbon, oxygen, &c. and increases its specific gravity,--is very evident from the effect produced. Wrought iron will occasion scintillations, somewhat of the same appearance, and steel, also, in greater abundance; and hence both are employed in sundry compositions. But the particular character, beauty, and brilliancy of Chinese fire must be attributed, first to the iron, and secondly to its peculiar state of combination with carbon and oxygen; for, we have said, that malleable iron, (which is deprived in a great measure of these substances in the operation required for its preparation), produces an effect far inferior to cast iron. This difference then can only arise from the quality, character, composition, or properties of these two kinds of iron. Steel, on the contrary, having a more vivid effect than wrought iron, owes its properties to another state of combination of the iron and carbon.
Hence we account for the difference in the appearance of the flame, and consequently the effect, in the different mixtures of crude iron, malleable iron, and steel. We have already remarked, in treating of iron, and in explaining the action of bodies in the process of combustion, in the section on the theory of fire-works, that the effect of some substances was to produce sparks, stars, &c. In the present instance, namely, the effect of the composition of the Chinese fire by combustion, the iron is first ignited by the powerful heat created by the combustion of the powder, nitre, charcoal, and sulphur, and in this state, is thrown out with violence, and is itself consumed. The combustion of iron is nothing more than its oxidizement, during which a brilliant fire, which characterizes so pre-eminently the Chinese fire, is produced. This oxidizement of the metal, in proportion as it is more rapid, necessarily gives rise to the phenomena of combustion, which, in this, and the generality of instances, presupposes a combination with oxygen. The fire is, therefore, more brilliant, as the combustion is more rapid, and the metal may be oxidized in a greater or lesser degree, but not to a maximum. From the effect taking place in the air, as it does not ensue, or is not seen, in the case, it follows, that the iron receives for the support of its combustion the oxygen of the air.
We have said, that the substances which compose cast-iron, are iron, carbon, and oxygen, in a peculiar state of combination. We may also conclude, therefore, that, as carbon, by combustion in oxygen gas, or in atmospheric air, which contains about twenty-two per cent. produces carbonic acid, the carbon of the iron during its combustion, is changed, by its union with oxygen, into this acid. The products, then, are oxide of iron, and carbonic acid, the latter existing in the gaseous state. With respect to the other products of combustion, arising from the gunpowder, saltpetre, sulphur, and charcoal, we have before noticed them. See _Gunpowder_, and the _General Theory of Fire-Works_.
We may remark, at the same time, that the intense heat, produced as well by the combustion of the gunpowder, as by the combustion of charcoal and sulphur, in contact with the nitrate of potassa, brings the metal almost to a state of fusion; which, being thrown off in this state, and considerably divided, is acted upon by the oxygen on all sides, causing the effect to be uniform and general.
The quantity of iron, it will be seen, which enters into the different compositions, is various, according to the particular purpose to which the composition is applied. The _effect_, therefore, may be varied, as we employ more or less of the iron; and the state of ignition may be affected, as the proportions of nitre and charcoal are increased or diminished. These facts are obvious, by referring to the respective formulæ, and the application of the several compositions. It is, besides, no less true, that as much care is required in selecting pure materials for every kind of artificial fire, as scrupulous accuracy, in following the proportions prescribed. Nor is this all; the mixture must be intimately made, or the effect would be doubtful and uncertain.
There is a particular manner required for preparing the composition of Chinese fire. All the substances must be passed three times through a sieve, except the sulphur, and the pulverized cast-iron. These are mixed by themselves, and afterwards with the other substances. They are turned over frequently with the hand. Cases are filled with it in the same manner as other compositions.
In order to make the mixture of the sulphur with the iron more intimate, the latter may be wetted occasionally with spirit of wine, which should contain no water, as water would tend to rust the metal, and injure its effect. The sulphur would then mix with more freedom, and the composition be more perfect. The spirit of wine, acting merely as a vehicle, afterwards evaporates; and, as it has no chemical action on either the sulphur or the metal, they would remain unaltered.
By proceeding in this manner; namely, first mixing the other substances by themselves, and afterwards the iron and sulphur, and then the whole, we form an intimate mixture throughout.
The composition, prepared in this way, makes the fire more brilliant; giving it a greater lustre than by proceeding in a contrary manner.
We are informed, that spontaneous combustion has frequently taken place, by suffering the iron and alcohol, or spirit of wine, to remain in contact; and, although this appears an anomaly, which we will not attempt to explain, yet that it is a fact, and that it has occurred at Paris, we have the authority of M. Morel.
When the cast-iron is reduced to powder, or _sand_, it is divided into several sorts, which are proportioned to the caliber employed. These sorts are marked or numbered, and are used as follows: For calibers under 7/12ths of an inch in diameter, No. 1; for those of 7/12ths to 10/12ths, No. 2; and for larger calibers, No. 3.
In charging with the composition, care must be taken to turn it over repeatedly at every other ladle full; because the iron, which is the heaviest substance, is liable to fall to the bottom. If the composition be not equally diffused, the fire would be irregular, and go out by puffs. This is a defect which ought to be guarded against.
The mixture of the composition for _Jessamine_ is made in the same manner.
Chinese fire, in cases, is commonly employed in garnishing, as it is called, the circumference of a decoration, or in forming pyramids, galleries, yew trees, cascades, palm trees, or in short, in producing a variety of figures, according to taste and fancy. They are often employed in turning pieces for their last fire, in consequence of the brilliancy of their effect.
We are told, that nothing is more elegant than Chinese fire; and that it forms, in its descent, flowers of variegated beauty, which, being scattered about by the rotation of the piece, resemble the _hydraulic girandole_ in the rays of the sun.
Chinese fire, however, has little force; and hence, when it is used, it is accompanied with other fire, as two or more jets of white fire. The latter is only employed, when the Chinese fire is to be exhibited on wheels, or turning pieces. When it is on fixed pieces, there is no occasion for them. Cases of Chinese fire, when burnt alone, will not turn a wheel.
As the effect of Chinese fire on wheels depends greatly on the motion of the wheel, its velocity should therefore be accelerated; which, although the duration of its effect would be shorter and more brilliant, may be produced by employing several cases of white fire, and communicating their fire one to the other by leaders in the usual manner.
There is no doubt, that the accelerated motion of the wheel causes the composition to burn more rapidly, in the same way as a bellows excites the heat of a blast-furnace; and, therefore, the increased brilliancy of the fire may be attributed to the greater rapidity of the combustion, which necessarily produces, in a shorter time, the oxidizement of the iron, and, at the same time, the combustion of the other substances.
With respect to the comparative force of compositions, or that power by which cases, as rockets, &c. ascend, or which gives motion to vertical and horizontal wheels, we may observe generally, that these effects depend on the compositions employed; and that the _recoil_, in such instances, is proportionate to the impelling power; for the resistance with which the fire meets from the air, in the immediate vicinity of the caliber of the case, causes a reaction, which produces the recoil, and consequently the motion of the wheel. That this effect depends, in a greater or less degree, on the composition we use, and the manner the case is charged, is very evident. (See _General Theory of Fire-Works_. Part 1.)
_Composition of Chinese Fire for calibers under ten-twelfths of an inch._
Meal-powder, 16 oz. Saltpetre, 16 -- Sulphur, 4 -- Charcoal, 4 -- Pulverized cast iron, 14 --
_Another of the same._
Meal-powder, 16 oz. Sulphur, 3 -- Charcoal, 3 -- Pulverized cast iron, 7 --
_Another, for Palm-trees and Cascades._
Saltpetre, 12 oz. Meal-powder, 16 -- Sulphur, 8 -- Charcoal, 4 -- Pulverized cast iron, 10 --
_Another, white, for calibers of eight and ten-twelfths of an inch._
Saltpetre, 16 oz. Sulphur, 8 -- Meal-powder, 16 -- Pulverized cast iron, 12 --
_Another, for Gerbes of ten, and eleven-twelfths and one inch caliber._
Saltpetre, 1 oz. Sulphur, 1 -- Meal-powder, 8 -- Charcoal, 1 -- Pulverized cast iron, 8 --
It may be proper to remark, that the above formulæ are all approved; as they have been used in France, and are given on the authority of Morel and Bigot. We are informed, indeed, that these proportions produce the most perfect fire, which surpasses the fire of the Chinese. From the many experiments made in France, instituted with the view of determining the best proportions, and leading, in fact, to the improvement of the original composition, we do not hesitate to give them the preference over all others.
In the composition of wheel-cases, Chinese fire is sometimes used, and then only for decoration; but in nearly all the compositions employed, in wheel-works, for standing or fixed cases, sun-cases, &c. steel-dust forms a constituent part. The proportion it bears to other substances is various: _viz._ to meal-powder, as one to five, one to ten, &c. In one of the formulæ for brilliant fire, the proportion is still greater, and in another less; but by mixing seven and a half ounces of steel-dust with meal-powder, saltpetre, and sulphur in the proportion of eleven pounds, one pound two ounces, and four ounces respectively, a composition is formed, calculated to produce a brilliant fire. But as this subject will be considered, when we treat of wheel-works, standing pieces, &c. and the different compositions appertaining thereto, we would only observe, that Chinese fire should always be preferred, where the object is decidedly appearance, with brilliancy and splendour.
_Sec. IV. Of Bengal Lights._
We have had occasion to mention heretofore, that metallic as well as the crude, or sulphuret of, antimony, entered as a component part into some compositions, in order to vary the effect and appearance of the flame. That this is the effect, in the composition, which constitutes the Bengal lights, is a fact well known, and to which its particular character is owing.
Bengal lights, in consequence of the whiteness and brilliancy of their flame, are considered as highly important in fire-works. The composition was a long time kept secret, and artists were at a loss to compound it, for those who possessed the secret, it appears, would not divulge it. Simple as it is, it was not known, until many experiments were made, which proved its identity with the original Bengal composition; and, since that time, it has been confirmed by the original formula. Morel assures us, that he purchased the secret.
_Composition of Bengal Lights._
Saltpetre, 3 lbs. Sulphur, 13 oz. 4 dr. Antimony, 7 oz. 4 dr.
They are pulverized and mixed in the usual manner, and passed three times through a hair sieve. Any quantity may be made at one time. The composition is usually put in earthen vessels, without decorations. They may be of different sizes, and, in fact, as broad as they are high, sufficiently large, however, to contain the composition. A small quantity of dry meal-powder is scattered over its surface, and a sheet of paper is tied on to secure it. It is primed with port fire match.
The _effect_ of this mixture is evidently that of the combustion of the sulphuret of antimony, as well as of the sulphur. The nitre furnishes the oxygen to both, and, as the combustion is rapid, the metal is oxidized, probably forming the antimonic acid, as the antimony may be oxidized to the maximum. There is another view, in which this combustion may be considered. According to the present theory of the formation of sulphuric acid, by the combustion of sulphur, and nitre in leaden chambers, it appears, that sulphurous acid is first produced, and nitric oxide gas, (deutoxide of azote), is also formed; and that the latter by uniting with the oxygen of the air is changed into nitrous acid, which is _then_ acted upon by the sulphurous acid, and is decomposed. Part of its oxygen combines with the sulphurous acid, changing it into the sulphuric, and deutoxide of azote is reproduced. In all probability, then, in the combustion of the composition of Bengal lights, the nitric oxide itself may affect the combustion of the antimony, which, as it would be enveloped in nitrous acid vapour, arising from the union of nitrous gas and oxygen, may present, in a measure, one of those cases of combustion, in which nitric oxide acts as a supporter, affording on that account a particular phenomenon. Reasoning _a posteriori_, this may be affected again by the formation of sulphuric acid; for a part of the sulphurous acid may be changed into sulphuric, not by its immediate union with the oxygen of the nitre, according to the old theory, but by the decomposition of the vapour of nitrous acid. This conclusion, however, is sufficient, that the nitre is decomposed, and during its decomposition, the sulphur and antimony are brought into action; that a large quantity of caloric and light is evolved, whether from the oxygen gas of the atmosphere, or the substances themselves we will not stop to inquire; and, that, in the act of combustion, the sulphur and antimony are acidified, forming new products.
It will be seen, by examining the formulæ for the composition of the white and blue-lances, that they both contain antimony, but in different proportions: thus, in the white lance, the proportion of antimony is as one to eight of sulphur, as one to sixteen of saltpetre, and as one to four of meal-powder; and in the blue-lance, as it is composed only of saltpetre and antimony, the proportion of the latter to the former is as eight to sixteen. In the composition of Italian roses, or fixed stars, the proportion of antimony is still smaller, and is as one to ten of sulphur, one to sixteen of saltpetre, and one to twelve of meal-powder. Now, by comparing these proportions with those which constitute the Bengal light composition, they will be found to differ from those compositions, into which the same substances enter; for, in the Bengal lights, the proportion of the antimony to the sulphur is as five to nine, and to the saltpetre, as five to thirty-two, or thereabout.
The inference we draw, therefore, is, that the white lance composition differs from the blue, in containing meal-powder and sulphur, and the latter from the former, in containing no sulphur, but eight times as much antimony; that the white-lance composition varies from the Bengal light, by containing one-half less of saltpetre, one-fifth less of antimony, and one-ninth less of sulphur; and that the Bengal composition differs from the blue lance composition, in having double the quantity of saltpetre, nine parts of sulphur, (the blue-light having none,) and nearly one-third less of antimony. If we attend to these proportions of the antimony, with the other ingredients, in the respective preparations, we will find, that the difference, in the proportions of the antimony, produces, with the presence or absence of the meal-powder and sulphur, and the difference also in the quantity of the latter, the phenomena or effects which characterise them. It is thus, therefore, with this, as with other preparations; only vary the proportions, and institute new equivalents, as it were, in any particular preparation, and adopt some and reject other substances, and the effects are varied agreeably thereto; and, if improvements are to be made in any composition, they can only be effected by experiment, and the investigation of the effects of new proportions, a comparison of which, with the effect of any particular composition, prepared according to a given formula, can alone determine the relative value of any new formula.
_Sec. V. Of Roman Candles._
Roman candles are formed on a roller seven-twelfths of an inch in diameter, and are generally fifteen inches in length. They are choaked at one end, and tied in the usual manner. According to the nature of the charge, which we shall mention, their effect is to throw out brilliant stars, to the height of one hundred and more feet, and when arranged with marrons, they finish with a report.
After the cases are formed, and ready to be filled, the operation is performed with expedition, by tying a number of them together, and charging them in that manner. The cases are charged with the rocket composition, heretofore described, in the following way: A ladleful of composition is put in, and rammed, using seven or eight blows with the mallet; a small spoonful of powder is then added, and afterwards a moulded star. This star should fit the caliber of the case. More of the composition is then added, then meal-powder, and afterwards a star, and these are repeated in the same order, till the case is completely charged. Care must be taken in observing this order, otherwise the effect would be destroyed. In striking with the mallet, attention must also be paid, that the blows are not too violent, or the star might be destroyed. When the cases, or candles, are charged, we untie them, and roll some coarse paper round each end of them, at the extremity, and round the choak.
We may remark, that in the charging of Roman candles, as their effect depends greatly on the appearance of the stars, which issue out in succession, too much care cannot be used in preserving the star composition entire. To do this, much art is required in putting in, and ramming, the rocket composition, so as not to injure or break it. The quantity of gunpowder to each star must be small, otherwise it might burst the case. Roman candles may be fired singly or several at a time, according to the effect required. To fire one in a chandelier, for instance, it is only necessary to prime it with priming paste; but, if we wish to form batteries in an artificial fire-work, in order to produce a variety, or to mount them on fixed or moveable pieces, we may, if necessary, terminate their effect with marrons, which may be effected by uniting them in such a way as to make the fire of the one, at a given time, communicate to the other. This communication is usually made through the choak, by attaching a match, which is carried to the mouth of the marron; so that, when the candle has burnt out, the last portion of the fire may pass to the marron, the effect of which is instantaneous. If necessary, priming paste may be used to facilitate the communication of the fire. The marron may be fixed directly under the bottom of the candle, by making the whole solid by a paper cylinder, which fits over the ends of both.
The mosaic candles, as well as mosaic simples, are formed in cases of the same thickness as sky-rockets, from which they differ in the introduction of stars along with the composition. We may remark, also, that they are rolled without pasting; and although Morel recommends choaking the cases, yet a writer of more recent date, M. Bigot, whose practical knowledge must be great, recommends _plugging_ them on the stick or roller. This is done by merely turning the end down about half an inch, and then beating it. Before the composition is added, he advises, also, the introduction of two or three fingers' thickness of clay, which is rammed very solid. This answers for a base, and supersedes the necessity of choaking. If, as we before remarked, it is necessary to communicate fire from this end to a marron or any other case, the clay must be bored to the composition, and quickmatch inserted; or, instead of this, the case itself, above the clay, may be perforated, and a communication in this way made.
Besides the ordinary Roman candles, intended expressly for exhibition, there is another preparation, which goes under the name of the incendiary Roman candle, used for the purposes of war. This preparation is composed of three parts of sulphur, four parts of saltpetre, one part of antimony, and half a part of meal-powder; but this, together with the incendiary stars, we purpose to consider when we treat of _Military Fire-works_.
_Sec. VI. Of Mosaic Simples._
Mosaic simples are in reality nothing more than a variety of the Roman candle, being formed in the same manner, and of the same composition, except that the moulded stars are different, and produce another effect. The mosaic simples produce merely a tail, or spout of fire; whereas the Roman candle throws out a brilliant star. They may be used with marrons in the same manner as the Roman candle. The length of the case is fifteen inches, and seven-twelfths of an inch in diameter. Mosaic simples are very appropriate to terminate a piece. A number of cases may be used by placing them in such a manner, that their fires may cross each other, an effect more striking than the ordinary mode of exhibition. This may be accomplished by arranging them, two and two, to a horizontal stick, observing that their mouths are up, and that they cross each other. They are lashed to the stick, and leaders are carried from the mouth of one to the mouth of another. This communication is so managed, that two pieces discharge at the same time. They may be employed in a variety of ways, according to fancy.
Sometimes pyramids forty or fifty feet high are furnished on each side, with cases of mosaic simples, with a star at the summit, and white and coloured lances differently dispersed.
The curtain of fire, produced by so many cases, the height to which it rises, the appearance of the star with the variegated and diversified effect of the coloured lances, all contribute to the splendour of this arrangement.
_Composition of the Mosaic Moulded Stars._
Saltpetre, 4 oz. Sulphur, 4 dr. Meal-powder, 16 oz. Charcoal, 3 --
Or in proportional parts: saltpetre, four parts; sulphur, half a part; meal-powder, sixteen parts; and charcoal, three parts.
These substances, being finely pulverized, and intimately mixed in the usual manner, are combined with gum-water, &c. as directed for preparing _stars_, and cut into lozenges, which are then rolled in priming powder, and dried in the shade.
_Sec. VII. Of Mosaic Tourbillons._
We may merely remark, as we have mentioned tourbillons heretofore, that the cases for the mosaic tourbillons, by which name they are designated, are seven inches in length, five-twelfths of an inch in interior diameter, and nine-twelfths in exterior diameter; and that the composition with which they are charged, is composed of sixteen parts of meal-powder, and three and a half parts of pulverized charcoal. See _Tourbillon_.
_Sec. VIII. Of Hydrogen Gas in Fire-Works._
M. Diller, some years since, exhibited at the pantheon of Paris, artificial fire produced by the combustion of hydrogen gas. From the short account we have of this exhibition in the _Dictionnaire de l'Industrie_, vol. iii, p. 39, it seems, that he employed three different airs, or gases, and produced three different flames: viz. white, blue, and green, which were made by the mixture of the three gases; and that he represented very perfectly, suns, stars, triangles, the cross of Malta, and sundry figures of animals in motion.
We may remark, that, if hydrogen gas be pure, the flame is of a yellowish-white; but this, however, is seldom the case, as the gas is always more or less impure, and, according to the substances it may hold in solution, so is the flame tinged. It is most usually reddish, because the gas holds in solution a little charcoal. In Cartwright's fire, ether is always mixed with the whole, or a _part_ of the gas, which is brought to the state of vapour by the application of a gentle heat, or even by immersing the bladder of gas, which contains the liquid ether, in hot water.
When combined with arsenic, in the form of arsenuretted hydrogen gas, hydrogen burns with a blue flame; combined with phosphorus it takes fire spontaneously, producing a white flame with a beautiful corona, caused by the formation of water; and when combined with sulphur, forming sulphuretted hydrogen or hepatic gas, it burns with a bluish-red flame, and a quantity of sulphur is deposited. Various mixtures of hydrogen with other gases, in due proportions, will produce different coloured flames; so that, by paying attention to this circumstance, the same variety of appearances may be produced, as in Diller's exhibition.
Bladders, (or sacks made of oiled silk, which are preferable), when filled with gas, and connected with tubes, revolving jets, &c. bent in different directions, and formed into various figures, and pierced with holes of different sizes, will, when pressure is applied, allow the gas to pass through the different tubes, jets, &c. which, when inflamed, will represent the sun and stars. If to this be added, triangular tubes, tubes in the form of the cross of Malta, or any other figure, they being pierced in their sides with a great number of holes not larger than the point of a pin; it is obvious, that fixed pieces may be represented, as well as revolving ones. In this manner, Diller must have made his exhibition.
Hydrogen gas is usually made, by pouring on zinc, or iron filings, in a gas bottle, sulphuric acid diluted with six times its weight of water. The latter is decomposed; its oxygen unites with the metal, and while the oxide is taken up by the acid, the hydrogen passes off in the form of gas. The gas may be received directly in the bladder or bag.
The _inflammable air pistol_ is nothing more than a hollow metallic cylinder, or an instrument in the shape of two cones joined base to base, and furnished with a touch-hole, and handle. This pistol is filled with a mixture of hydrogen and oxygen gases, or in lieu of the latter, atmospheric air; a plug or stopper is put in the caliber, and, when the touch-hole is brought in contact with a lighted taper, an explosion will take place, and the plug be sent out with much force. The same effect may be shown by passing the electric spark over the touch-hole, and hence, on an insulated stool, a person, charged with electricity, may set it off by the finger or nose. This pistol is usually called the Voltaic pistol, from Volta, who is said to have invented it.
M. Biot (_Traité de Physique Experimentale_, &c. tome ii, p. 435) describes the Voltaic pistol as a metallic vessel of a spheroid shape, furnished with an aperture and pipe, and with a conductor for the electric fluid, which passes through the middle of the vessel. This conductor is insulated, as it goes through a glass tube, and extends to within an eighth of an inch of the middle; and directly opposite to this conductor is a metallic wire, having, like the first conductor, a small metallic ball on its end. This conductor is placed a short distance from the first; so that, when the electric fluid is conducted, it passes from one ball to the other within the pistol, and hence inflames the hydrogen gas. With respect to the form of the pistol, it is of no moment whether it be cylindrical, conical, or globular, as the effect is the same, provided that it contain a sufficient quantity of gas, and the spark is conveyed through the gas, or the gas is inflamed by a vent. The air pistol described by Brande (_Brande's Chemistry_) is cylindrical, or rather in the shape of a cannon, and, where the touch-hole should be, there is an insulated conductor, which conveys the spark to the interior.
The _Voltaic lamp_ is also a contrivance by which hydrogen gas is inflamed by the electric spark, which sets fire to a taper. The original lamp has been greatly improved, and simplified. The eudiometer of Volta is another contrivance by which hydrogen gas is burnt, in a strong tube, by the electric spark.
The detonation of inflammable air may be shown over a pneumatic tub, by filling metallic gas-holders with a mixture of hydrogen gas and atmospheric air. When flame is brought in contact with the mouth of the gas-holder, an explosion will immediately take place. Soap-bubbles, blown with hydrogen gas, mixed with atmospheric air, will take fire, on presenting a lighted taper, and give a slight explosion. The ascension of these bubbles demonstrates, that the gas is lighter than atmospheric air, and it is its extreme levity that fits it for the purpose of filling balloons. It may be made twelve times specifically lighter than atmospheric air, by passing it over dry muriate of lime, in order to absorb the moisture it may contain, provided the gas be free from carbon, or carbonic acid.
Light carburetted hydrogen gas, or _fire-damp_ of miners, is that gas, which so often formerly produced many dreadful accidents by its explosion. The invention, by Sir H. Davy, of the safety-lamp prevents this effect.
The principle of this most valuable discovery, appears to be altogether in the fine metallic gauze case, which surrounds the flame of the lamp; so that, as it is found by numerous and repeated experiments, the inflammable air, if present, cannot take fire outside of the gauze; in other words, the flame, in the interior of the case, is prevented from setting fire to the exterior atmosphere, however explosive it may be.
Hydrogen gas, in combination with carbon, is not only generated in mines and coal pits, (in the latter of which, it is the most abundant), but is frequently found on the surface of springs in the form of bubbles, usually however combined with sulphur; and in many places on the surface of the earth. It may be inflamed by a candle. The burning springs consist of this gas which is set on fire, and the combustion is kept up by a constant supply of gas from the same source. In the East, this gas is very often conveyed under ground through hollow reeds, and is constantly kept burning. At other times, it is conveyed to the sacred temples, as with the Zoroasters, and burnt as _holy fire_; and in some countries, it is so abundant, that the natives employ it as fuel for boiling their pots. It is found in different parts of the United States. A striking incident, showing its effects, occurred lately near Cincinnati, in the state of Ohio. It appears, that, in making an excavation, and boring for salt water, the workmen penetrated their augur into a cavity, which contained an abundance of gas, and which, with the water, made its way to the excavation. Not suspecting that the gas was inflammable, or being unacquainted with it, and apprehending no danger, they brought a lighted taper; and the gas, being mixed with atmospheric air, exploded with a noise so considerable, that it was heard several miles in the neighbourhood. The men were much burnt, some of them dangerously.
The gas was afterwards inflamed by applying a taper, as it rose in bubbles from the surface of the water.
The philosophical candle is nothing more than hydrogen gas set on fire as it proceeds from a capillary tube, being formed in a bottle to which the tube is attached. The most brilliant flame, however, is produced by hydroguret of carbon, or olefiant gas.
Inflammable air is often generated in the stomachs of dead persons, for, on applying a lighted candle, the _vapour_ has been known to take fire. Dr. Swediaur relates some instances of the same kind, but in living persons, in which the _urine_ of the by standers was made use of. According to several authorities, combustion has been known to take place spontaneously in living persons. Lair, however, is of opinion, that, in these cases, it must have occurred by some slight external cause, such as the fire of a candle, taper, or pipe. There can be no question as to the developement of hydrogen gas.
Morse, (_Universal Geography_, article Persia, p. 588), after mentioning the Persian _guebres_, the disciples and successors of the ancient magi, and followers of Zoroaster, speaks of a combustible ground about ten miles distant from Baku, a city in the north of Persia, as the place for their devotion. This ground contains several old temples, and is remarkable for the quantity of inflammable air it emits, which is employed to produce the _sacred flame of universal fire_. If the ground be penetrated with a stick, there will issue out such a prodigious quantity of inflammable air, as, when lighted, will burn for a considerable time. This gas, we remarked, is employed there for lighting, cooking, and other purposes. The naphtha districts, in Persia, furnish this gas in abundance. See _Naphtha_.
A Sandusky (Ohio) paper states, that, about one mile and a quarter from Milan, is a place just in the edge of the water of Huron river, where there is a current of inflammable gas, that burns with a clear bright blaze, and is in sufficient quantity to light ten houses.