CHAPTER IV.

OF SCENTED FIRE-WORKS.

There is a variety of scented fires, all partaking, in a greater or lesser degree, of a peculiar flavour, according to the substances, which enter into their composition. It is a fact, that, in the ordinary odoriferous fire, into which, either the so called scented gums, or essential oils, enter as a component part, these substances are not only decomposed in the act of combustion, but evolve, during that process, a part of their respective _odours_, to which we attribute the _scent_ imparted to the atmosphere. In those instances, in which gunpowder forms a part of the composition, it is to be remarked, that the peculiar smell of fired gunpowder is scarcely recognized, owing to the preponderance of the scent in the composition. Hence it is, that scented fire-works are more calculated for confined places than for the open air.

Scented fires are various both in their nature and composition, and may always be so modified, as, in their effect, to produce, not only the particular flame, or appearance of the fire, but the extrication, along with the gaseous products, of the odour of the essential oil, or other substance made use of.

Linnæus, in a dissertation on the odours of different substances, endeavoured to classify them. M. Lorrey (_Mémoires de la Société Royale de Medicine_ 1784) divided them into five classes; viz. camphors, narcotics, ethers, volatile acids, and alkalies; but it is obvious, that it is an impossibility to class all the odours which exist, and may be formed by the mixture, or combination of various substances. We may consider them either pleasant, or unpleasant to the sense of smelling. But as we recognize bodies very frequently by their odour, with which we become familiar, as camphor and assafœtida, for instance; so the olfactories may be affected by other odours. Aromatic and fetid odours are opposite to each other. Some of the gases, as the olefiant, have a fragrant smell, and others, as hydrogen, and sulphuretted hydrogen, either alone or mixed, are extremely unpleasant. The intestinal gas (_gas intestinaux_ of the French) is a particular instance of the odour of a compound gas, or mixture of gaseous fluids. The experiments of M. Jurine of Geneva, of MM. Chevreul and Magendie, (_Ann. de Chim. et de Phys._ t. ii, 294), of M. Vauquelin, (_Journal de Pharmacie_, t. iii, p. 205), and of MM. Lameyran and Fremy, (_Bulletin de Pharmacie_, t. 1, p. 358), are interesting on this subject. Intestinal gas differs in its composition. It always contains carbonic acid gas, and azotic gas, and hydrogen gas, either pure, or combined with carbon and sulphur. Thenard (_Traité de Chimie_, iii, p. 576) contains some observations on this subject.

In the camphor odour, Lorrey includes not only camphor itself, but various species of laurel, myrrh, and turpentine. In the narcotic odour, he embraces opium, various gum-resins, roses, lillies, jessamine, &c. and musk, amber, and castor. In the ethereal odour, different kinds of ether. Under the odour of volatile acids, he considers that of fruits, aromatic barks, citron; and under the alkaline odour, the acrid, and, in general, the antiscorbutic plants. Fourcroy, in treating of the aroma of plants, or the _spiritus rector_ of Boerhaave, (_Bulletin de la Société Philomatique_, an. 6, p. 52,) has some interesting facts on this subject.

It is evident, that perfumes, so called, owe their peculiar fragrance to an essential oil, which characterizes each kind; for the essential oil obtained by distillation, partakes of the odour of the plant. Hence the oils of mint, roses, thyme, cinnamon, cloves, &c. &c. all of which are peculiar in this respect. Odoriferous fire-works owe their particular properties to the presence of some gum, resin, or oil. As to the expansibility, or rather the divisibility of odour, several interesting facts are known. In a work, entitled _l'Existence de Dieu, par les merveilles de la Nature_, we are informed, that, if we take the one-fourth of a drachm of benzoin, and place it in the four corners of a room, the odour will be recognised in an instant. The chamber in which the experiment was made, the author states, was 24 feet by 16, and contained 9212 cubic feet of air, which, multiplied by 1000, would give 9216000 inches, and 1000000 parts of an inch were rendered appreciable. Therefore, he infers, that 9216000000000 are equally perceptible in the chamber. Prevot (_Bulletin de la Société Philomatique_, an. 6) has some observations of the same nature, respecting camphor. If such are the effects with benzoin, what, we may ask, would be those of the more powerful perfumes, such as musk? One grain, or perhaps the tenth part of a grain of musk, would scent the atmosphere of a room very perfectly.

De Laval (_Description of the Maldiva Islands_) mentions the use of scented fire by the inhabitants, in the celebration of their festivals. On the day of every new moon, they place at the entrance of the churches, and the gates of their houses, cocoa shells cut in the middle, and filled with white sand and burning coals, upon which they burn, almost all night, sweet scented gums and woods; and at the nocturnal festival, called _maulude_, the night on which Mahomet died, their halls are illuminated with a multitude of lamps, and the air is filled with the smoke of perfumes. The use of scented fire appears to form a principal part of their devotional exercises. Perfumes are even burnt on the graves of deceased persons.

Having mentioned the use of odoriferous plants in scented fire, we may add, that all plants possess some peculiar character, if aromatic, which, as one of their characters, serves to distinguish them.

The qualities of plants are said to be similar, when they have the same taste and odour. The odours of plants, Richard divides into 1. Fragrant, 2. Aromatic, 3. Ambrosiac, or resembling amber, 4. Alliaceous, or resembling garlic, 5. Fetid, 6. Nauseous. The three first are innoxious.

In the composition of scented fire-works, it is also to be observed, that gunpowder does not always form a part; and hence their character is various, according to the purposes they are applied to, or their uses.

In the odoriferous water balloons, (for which, see _aquatic fire-works_), we have, for instance, along with saltpetre and other substances, in the different compositions, either amber and flowers of benzoin; or frankincense, myrrh, and camphor; or amber, cedar raspings, and the essential oils of roses and bergamot; or the saw-dust of juniper, cypress, camphor, myrrh, dried rosemary, cortex elaterii, and oil of roses. These are the substances, therefore, which enter into the different compositions, in the order here given, and which impart to the fire an odoriferous character. The relative proportions may be learnt, by referring to the chapter on _Aquatic fire-works_.

Scented fires are, however, little used. Their effect is nevertheless agreeable in close rooms; but in the open air they lose this property, or rather it is not perceptible, owing to its extreme division.

The _vases of scent_ were greatly employed in the public feasts and ceremonies at Rome, Athens, and, above all, in Egypt. In temples, palaces, &c. they were mostly used. The vessels, which contained the composition, were placed by the Athenians in sculptured or painted vases, as well to hide their appearance, as to serve for ornament.

_Sec. I. Of Pastilles._

Pastilles, or fire crayons, are small conical troches, in the form of a loaf, of one and a quarter inches in height, and about an inch thick. They are made of the following composition, which is moistened with rose-water, having some gum arabic previously dissolved in it. The paste is made neither too thick nor too thin, but of a sufficient consistence to work with the hand.

_Composition of Pastilles._

Storax calamite, 2 oz. Benzoin, 2 -- Gum Juniper, 2 -- Olibanum, 1 -- Mastich, 1 -- Frankincense, 1 -- White or yellow Amber, 1 -- Camphor, 1 -- Saltpetre, 3 -- Charcoal of the linden, or willow, 4 --

The pastilles are burnt upon a plate, and communicate to the air an agreeable odour.

_Odoriferous paste._

Gum Benzoin, ½ oz. Storax calamite, 4 scruples. Peruvian balsam, (dried) ¼ oz. Cascarilla, 4 scruples. Cloves, ½ drachm. Charcoal, 1½ oz. Nitre, 1 drachm. Oil of Lemon, ½ do. Tincture of Amber, ½ do.

The dry substances are pulverized very fine, and mixed intimately together, and the oil of lemon and tincture of amber then added. The whole is then made into a thick paste with common mucilage, and formed into pieces as before mentioned. These pieces ought to be conical. When used, they are placed on a stone, or a piece of metal, and inflamed. This composition is said to burn with scintillations, and to exhale a very fragrant and agreeable odour. See _Dictionnaire de l'Industrie_.

_Perfume for Apartments._

Orrisroot, 1 oz. Benzoin, ½ -- Charcoal, ¼ -- Ess. Bergamot, 1 drachm.

These ingredients are mixed into a paste in the usual manner, with orange flower water, and a small quantity of gum. A small portion, when dry, thrown on ignited coals, will exhale an agreeable odour.--_Ibid._

M. Brillat-Savarin (_Archives des Découvertes_ iii, p. 328) has invented a machine, which he calls the _irrorateur_, for perfuming apartments. He objects to the ordinary mode of perfuming by fire, and sprinkling odoriferous fluids in a room. His _irrorateur_ consists of a small fountain, which, by compression, forces out the odour required, and may be conveyed to any place.

_Sec. II. Of Vases of Scent._

We observed, that these vases were much in use at the public feasts and ceremonies of the Athenians, Romans, and Egyptians.

_Composition for the Vases._

Storax, 4 oz. Benzoin, 4 -- Frankincense, 4 -- Camphor, 2 -- Gum Juniper, 1 -- Charcoal of the willow, 1 --

These substances are pulverized, and intimately mixed, and oil of juniper is added. The mixture is put in an earthen vessel, having a cotton, similar to a wick, supported by means of a wire. Among the ancients, the earthen vessels were afterwards placed in sculptured, or otherwise ornamented vases. By using stone-ware vessels, and mixing the composition with the spirit or oil of turpentine, the combustion will be more rapid, and the flame more enlarged.

_Sec. III. Remarks on Spontaneous Accension._

The spontaneous accension of spirit of turpentine by the addition of nitric acid, might furnish also a means of preparing a scented fire extemporaneously; by putting into the vessel, previously to the spirit of turpentine, the composition above mentioned. See _Nitric Acid_, in the article _Nitre_.

An extemporaneous fire may also be prepared, by placing, on the scented mixture, the following composition, namely, chlorate, or hyperoxymuriate, of potassa and sugar, and touching the mixture with a glass rod dipped in sulphuric acid, or oil of vitriol. The fire will then communicate to the other materials. See _Chlorate of Potassa_ and the article on _Pyrophori_.

Camphor, which imparts an agreeable odour, may be readily inflamed in this manner, and the experiment even be made on snow or ice. See _Camphor_.

_Sec. IV. Of Torches, and Odoriferous Flambeaux._

Flambeaux are usually wax torches. Odoriferous flambeaux may be formed by melting with the wax, camphor and frankincense, and mixing with the whole, when fluid, some of the essence of bergamot. Although there are no directions given on that subject; yet, judging from analogy, a mixture of that kind would be an improvement on the flambeau, when it is to be used in rooms or for particular occasions. They may be made either large or small, with a wick of a proportionate size.

Torches are principally used for military purposes, to give light, when an army is marching at night, during sieges, &c. They ought not to be extinguished by wind or rain. The _Torches inextinguibles_, of the French, are of this character.

Torches are made in the following manner: Take four large cotton matches, three or four feet long; boil them in a solution of saltpetre, and arrange them round a pine stick. Afterwards, cover them with priming powder and sulphur, made into a thin paste with brandy. When dry, they are to be covered with the following composition:

_Composition for torches._

Yellow wax, 2 lbs. White turpentine, 2 -- Sulphur 12 oz. Camphor, 6 -- Pitch, 4 --

_Ibid._

White pitch, 32 parts. Hard turpentine, 4 do. Yellow wax, 32 do. Sulphur, 12 do. Camphor, 6 do.

_Ibid._

Black pitch, 24 parts. White pitch, 24 do. Turpentine, 4 do.

The second composition is that which is used in France, and, therefore, in all likelihood, is the best formula. The flame may be more or less scented, by using, at the same time, some of the aromatic substances before noticed. This, however, is unnecessary for common purposes. See _Fire-works used in war_. The flambeau, invented by Petitpierre, (_Bulletin de la Société d'Encouragement_, No. 102), is intended to give light to apartments.

_Sec. V. Remarks concerning Odoriferous and Fetid Fire._

Fire-works may be made extremely unpleasant to the olfactory nerves, by mixing with their compositions, sundry substances of an opposite quality to odoriferous oils and aromatic gums. It will be sufficient, however, to remark, that this effect is communicated more particularly, as in the _stink-balls_ of service, by using sulphur, rasped horses' and asses' hoofs, burnt in the fire, assafœtida, seraphim gum, and sundry fetid herbs or plants. The addition of the acid of amber, called succinnic acid, and, in the shops, the _salt of amber_, will give to the atmosphere in the vicinity of the fire, the peculiar property of causing a continual sneezing and coughing. Such are some of the opposite effects, which different substances produce in conjunction with fire-works. Some of these substances, it is obvious, would, if used in too large a proportion, retard, if not entirely prevent the combustion; and for that reason, they bear only a given proportion to the powder, nitre and charcoal, which forms the basis of some, as, for instance, the _stink-ball_ composition. But in such cases, the combustion being in itself rapid, and the degree of heat consequently proportionate, these fixed, and otherwise incombustible bodies, in a general sense, are acted upon by the fire, already created; and, therefore, the smoke that results must necessarily possess, and partake of the fetid qualities of the substances employed. On the same principle, we may account for the effect of the scented paste, and the scented vases; but with this difference, that many of those substances are themselves inflammable, and, during their decomposition, emit the odour peculiar to each of them. We know, that the elementary principles of these bodies are carbon, hydrogen, and oxygen, variously combined, some of which are, and some are not inflammable; and that, in combustion, when it takes place, they are decomposed and new products necessarily ensue from a new arrangement of the elementary principles.

It is difficult, however, to give the precise order in which decompositions by fire result; since the substances made use of are numerous and employed in given proportions; and since their action upon each other, depends frequently on external agents, anomalous circumstances, and causes which do not follow at all times the same order of succession. Generally speaking, however, we may obtain such a datum, all things being considered, a datum derived from the known laws of chemical decomposition, as will furnish a _rationale_ to explain both the cause and effect. See _General Theory of Fire-works_.

There is no doubt, that, by the action of fire on fetid, and particularly animal, substances, as _hoofs_, &c. products may be formed in the very act of combustion, which would increase the fetid properties of the smoke. Zimome, obtained from the gluten of wheat by alcohol, which takes up the gliadine, when thrown upon red-hot coals, exhales an odour, similar to that of burning hair or hoofs, and burns with flame. The _pyro-products_ are the immediate consequences of the decomposition of the substance; the elements of which either separate entirely, or recombine under some other form, as we find in the process of destructive distillation.

Bones, and other hard parts of animals, when subjected to distillation, furnish several products, as impure ammonia, animal oil, and the like. Wood also, we remarked, when treating of its carbonization for the formation of coal, produces, besides gaseous and other volatile products, the result of its decomposition, a quantity of acid liquor, formerly called the pyroligneous, but now the pyroacetic acid. By separating the empyreumatic flavour, which at first constitutes a part of the acid, the acetic acid is obtained in a state of purity. The pyro-tartaric acid is also the result of the action of heat; and we know, when animal substances are calcined with potash, they produce cyanogen, the basis of the hydrocyanic and ferrocyanic acids, the latter of which when united with the peroxide of iron, forms the perferrocyanate of iron, commonly called Prussian blue. Caromel also, that peculiar substance which is disengaged from sugar and various saccharine substances, when submitted to the action of heat, is a product, resulting from the decomposition of the sugar. The empyreumatic, or _burnt_ flavour of certain distilled liquors, which is corrected by redistillation with charcoal, or passing the liquor through a filter of charcoal, is owing to the same cause. The changes, that bodies undergo by partial roasting, are familiar to every one; as, for instance, the torrefaction of barley, after germination, in the preparation of malt, the degree of which determines the colour and taste of the beer; the roasting of rye and coffee, before they can be employed to form a beverage; and the torrefaction of the cocoa, before it can be made into chocolate, the sweet taste and brown colour of which are acquired in the process, are all examples of the effect of heat on bodies. The action of heat, according to its temperature, produces, therefore, effects of a particular kind; and, as we regulate the heat in such cases, we form products of different kinds. Destructive distillation, however, would again change the character of these products. Of this kind, we may consider the effect of the heat, produced in the combustion of inflammable substances. In a word, the action of heat may be so graduated, in the same manner as the tempering of steel, as to produce only partial changes, which must ensue at certain temperatures; or, by an increment of heat, in which a total decomposition takes place, the effect is regulated, by the force of affinities, exerting their influence under modified circumstances. Hence we perceive, by reasoning _a priori_, that as substances are altered by the action of heat, so they produce new compounds, according to the circumstances of the action, and with or without the agency of foreign bodies. These facts are so far applicable to the subject under consideration, as to enable us to explain, or account for the effects that result on the mixture, or combustion, of bodies, a knowledge of which is undoubtedly necessary to form a theory of fire-works in general.