Chapter II (6)

It will be sufficient to remark, that naphtha or rock oil is a yellow or brownish bituminous fluid, of a strong, penetrating odour, and so light as to float on spirits of wine. By exposure to the air, it acquires the consistence of petroleum. It takes fire on the approach of a lighted taper, and burns with a bluish flame, yielding a thick smoke. Plutarch and Pliny both affirm, that the substance with which Medea destroyed Creusa, the daughter of Creon, was naphtha. She sent a dress to the princess, which had been immersed in, or covered over with the oil, and which burst into flames as soon as she approached the fire of the altar. Plutarch relates that Alexander the great, was amused and astonished with the effects of naphtha, which were exhibited to him at Ecbatana. On the shores of the Caspian sea, it is burnt in lamps, instead of oil. There are copious springs of this oil in that neighbourhood, and it is sometimes obtained by distilling bituminous substances.

Hanway (_Travels through Russia into Persia_, i, 263,) mentions the naphtha of Baku, and remarks that the earth is strongly impregnated with it; for, he adds, by taking up two or three inches of the surface, and applying a live coal, the part which is so uncovered, immediately takes fire, almost before the coal touches the earth. Eight horses were consumed by the fire from naphtha, being under a roof where the surface of the ground was turned up, and, by some accident took fire. A cane, or tube, even of paper, set two inches in the ground, and the top of it touched with a live coal, and blown upon, immediately emits a flame, without hurting either the cane or paper, provided the edges be covered with clay. Three or four of these lighted canes will boil water in a pot.

Pinkerton, (_Petralogia_ ii, p. 148,) speaks of the naphtha of Baku, which exists on the western side of the Caspian sea, being carried to Constantinople, "where it formed the chief ingredient of the noted composition called the Grecian Fire; which, burning with increased intensity under water, became a most formidable instrument against an inimical fleet." See _Greek fire_.

Naphtha is obtained of several qualities by suffering it to remain in pits or reservoirs. The Persians, who use it in their lamps, and to boil their food, find it to burn best with a small mixture of ashes. They keep it at a small distance from their houses, in earthen vessels, under ground, to prevent any accident by fire, of which it is extremely susceptible.

Hanway speaks also of what is called the _everlasting fire_, about ten miles from Baku, which is an object of devotion to the followers of Zoroaster. Near the altar of their temple, he observes, is a large hollow cane, from the end of which issues a blue flame, which the Indians pretend has continued to burn ever since the flood, and which, they fancy, will last to the end of the world.

We have no hesitation in believing, that the ancients made use of this oil in their exhibitions; and, from its properties, that when mixed with other substances, it would make a brilliant fire-work.

Petroleum, called also mineral tar, is less fluid and less transparent than naphtha. It has an oily consistence, more or less viscid. It occurs of a black or brown colour. It burns rapidly, but not so readily as naphtha, and exhales a black smoke. By distillation, it forms a liquid like naphtha, and leaves a thick tar in the retort.

It exudes from rocks, is found in wells, &c. In Pegu, the wells furnish annually 400,000 hogsheads. It is used there in the place of oil for lamps. When boiled with rosin, it is used for painting houses, and the bottoms of vessels. In the embalming of dead bodies, it was employed by the ancient Egyptians; and, in some countries, clay, soaked in it, is used as fuel.

It is found in the United States, in Kentucky, Ohio, the western parts of Pennsylvania, in New York at the Seneca lake, &c. The Seneca or Genessee oil is the same bitumen.

When petroleum is exposed to the atmosphere, it acquires a greater degree of consistence, and passes into another bituminous substance, called maltha. This has the properties, and frequently the appearance of pitch. When burnt, it yields more smoke and soot than petroleum. According to its original meaning, it signifies a kind of cement; and the maltha mentioned by Pliny, Heineccius, Festus, and others, which was employed in the same manner as our modern sealing wax, was a mixture of pitch and wax, and was also used to make reservoirs, pipes, &c. water-tight. Maltha also sometimes resembles wax. Mr. Kirwan, however, gave it the name of mineral tallow.

Mineral or Barbadoes tar is somewhat thicker than petroleum, and nearly of the consistence of common tar. It is used for the same purposes as the ordinary petroleum. Elastic bitumen, a variety between the softer and harder bitumens, resembles caoutchouc. It burns with a bright flame, and bituminous odour.

Asphaltum, or solid bitumen, is much harder than pitch, brittle, and of a brownish-black colour. It burns freely, and leaves but little residue. In Judea, it is found on the waters of the Dead sea, or the lake of Asphaltes. It is also called _Jews' pitch_. It was employed by the Egyptians for embalming under the name of _mumia mineralis_.

Both maltha and asphaltum were used by the ancients as a cement. The walls of Babylon were cemented with these substances, as obtained from the river Is, which falls into the Euphrates. It may be observed, that those countries, which yield bitumen, contain salt springs, and it frequently accompanies pyrites. Limestone, particularly the black, contains it, and the colour is often owing to its presence. The _stink stone_, or bituminous carbonate of lime, is of this kind. The retinasphaltum, a combination of bitumen and earth, having a yellow colour, burns with a bright flame, and fragrant odour, which at last becomes bituminous. Many stones, and particularly some of the black marbles, owe their colour to bitumen; hence they burn white. The bituminous schistus, or bituminous shale, sometimes contains so much of this substance as to burn in the fire. Jet is a mineral of a black colour, and resembles the cannel coal. It is inflammable, producing a green flame, with a strong bituminous odour.

With respect to bitumens, we may observe, that they all possess one character, that of being inflammable; and that they are more or less so in proportion as they partake of the principle of naphtha; or, at least, the rapidity of their combustion depends upon the presence of this oil. The following additional facts, therefore, with respect to naphtha, may be interesting: Certain liquids have the property of uniting with naphtha, which has also the property of dissolving and combining with solid substances, of which the following examples may be stated:

At the degree of ebullition, it dissolves sulphur, which, on cooling, is in part deposited in needle-form crystals. At the same temperature, it also dissolves phosphorus, part of which is again separated.

It unites also with iodine. With camphor, it also combines, and in large quantity. It takes up a much larger proportion of pitch. In the cold, its action on wax is feeble, but assisted by heat, it unites with it in all proportions. On lac and copal, its action is feeble. In the cold, it does not dissolve caoutchouc; but when assisted by heat, it dissolves this substance, though not completely. These facts may determine its action in certain mixtures.

According to Theodore de Saussure's Analysis, (_Bibliot. Universelle_, iv, p. 116), it appears, that naphtha is composed of 87.60 carbon, and 12.78 hydrogen.

_Sec. XIII. Of Oil of Spike._

This oil is principally used as a vehicle for mixing the ingredients of some kinds of fire-works; and, although it is employed in that way, yet it has also an effect in combustion, having similar properties with liquid bitumen. It enters into the composition of some of the preparations, and perhaps is equally good as liquid bitumen. Indeed, the oil of spike, as sold in the shops, and used principally by farriers as an embrocation for horses, is an artificial preparation, made by mixing together about five ounces of Barbadoes tar, with a pint of the spirit of turpentine.

_Sec. XIV. Of Amber._

Amber, succinum, karabe, the electron of the ancients, which are synonimous terms, is very inflammable. A piece of it, put on the point of a knife, and set on fire, will burn entirely away, emitting, at the same time, a white smoke, and a somewhat agreeable odour. It is used in the composition of fire-works, and particularly in some kinds of rockets. All the preparation it undergoes, when thus used, is to reduce it to powder in a mortar, and to pass it through a fine sieve. It also forms a part of the composition of odoriferous fire; but the formulæ for the latter are various.

Amber is of various colours, either yellowish, white, or honey-yellow. It is translucent, and sometimes transparent. It may be turned or polished. It occurs in grains or in irregular masses. Alluvial deposites of sand, gravel, &c. frequently contain it. It is also found with bituminous wood, brittle lignite, or jet, and with other substances. It has been discovered in New-Jersey, near Trenton, in alluvial soil. Naturalists believe, that amber was once a resinous juice. Masses weighing 20 lbs. have been found. Sometimes it contains insects. It is formed into beads and the like. As amber becomes electric by friction, and the ancients called it electron, the term electricity is derived from it. By distillation, it yields both an acid, (the succinic), and an oil. Jet is usually considered black amber.

We may introduce here a few remarks respecting ambergris:

Ambergris is a substance, which has a peculiar fragrance, and for that reason is used as a perfume, and may be employed like similar substances in odoriferous fire. As to its origin, we have no certain account; but it seems, from its general properties, to be formed in the same manner as bituminous substances, although it is mostly found on the sea-shore, where it has been probably washed up from the sea.

Ambergris is found principally on the shores of Ceylon, and is known to be good, by laying some of it on a very hot knife, when, if pure, it will not only melt and run like wax, but entirely evaporate, leaving no residue.

Ambergris, on account of its price, (the retail price in London being a guinea per ounce), is frequently adulterated with various mixtures of benzoin, labdanum, meal, &c. scented with musk. But pure ambergris, when heated, has a greasy feel, and appearance, and is soluble in hot ether and alcohol.

_Sec. XV. Of Camphor._

Camphor is a resinous substance, although generally called a gum, which has a peculiar, and powerful smell. It is obtained principally from the _Laurus Camphora_. It is extracted from this, and other trees in the East Indies. We are informed, that, in Borneo and Sumatra, the larger pieces which contain the most camphor, are picked out with sharp instruments. The Chinese cut off the branches, chop them small, and place them in spring water. They are then boiled, and stirred with a stick. As soon as the camphor is observed to adhere to the stick, the fluid is strained. It is then poured into a basin, and the camphor separates, in Japan, the roots and the extremities of the branches are steamed. It is also obtained by sublimation. The roots, wood, and leaves are all boiled in large iron pots, and the camphor is collected on straw, placed in a tubular head.

With respect to the refining of crude camphor, in order to produce _heads_, as they are called, and to free it from impurities, the operation is nothing more than sublimation. Sublimers made of glass are used; and into each, the camphor, along with a small portion of lime, is introduced, and they are then placed in a sand bath. Heat is applied, and the pure camphor rises and attaches itself to the upper part of the vessel, forming the refined camphor.

The general properties of camphor are the following: It is not altered by the atmospheric air, but is volatilized during warm weather. It is insoluble in water; is soluble in alcohol, forming the spirit of camphor, and also in volatile and fixed oils. It is not acted upon by the alkalies. It is dissolved in acids without effervescence, and by some it is decomposed. Nitric acid converts it into a peculiar acid, called the camphoric. It melts between 300 and 400 degrees. It takes fire, and burns with a white flame, and, generally, while it presents the character of a resin, it shows, by its combustion, like other inflammable bodies, that it contains, in its composition, a large quantity of carbon and hydrogen.

There are several species of camphor, which have been examined by chemists and which differ in their properties. These are, common camphor, the camphor of volatile oils, and the artificial camphor, formed by treating oil of turpentine with muriatic acid.

The base of camphor forms a constituent part of some volatile oils, which are in a liquid state; and for its separation, it appears to require a combination with oxygen.

Camphor may be apparently set on fire by means of water, an experiment, which is nothing more than producing chemical action by it, in the following manner: Put a portion of nitrate of copper on some tin-foil, along with camphor; then by adding some water, and quickly wrapping the foil up, pressing the edges close, it will inflame, and sparks of fire be produced.

Camphor has been used in the manufacture of candles. For this purpose, it is dissolved in brandy, and the wick, composed of equal parts of cotton and linen, is dipped in. It is then dried, and covered, in the usual manner, with tallow or wax. The tallow, recommended as the best for candles, is a combination of equal parts of mutton and beef suet.

Camphor is very soluble in acetic acid, which is highly inflammable. This solution is decomposed by water. When combined with essential oils, it forms aromatic vinegar. Romieu has observed that small pieces of camphor floating on water have a rotary motion.

Camphor enters into a composition, which is used to determine, like a barometer, the state of the weather, and the changes it undergoes. According to the _Journal de Pharmacie_, 1815, some experiments were made in France on the fluid taken out of one of the English weather gauges. The liquid contained water and alcohol, was strong with camphor, and reddened litmus paper. The tube contained 3-1/2 ounces. On analysis, its contents were found to be, 24 grains of alum, 120 grains of camphor, and enough water to dissolve the former, and alcohol to dissolve the latter. A similar composition was made, and put into a tube, which, it seems, had the same effect. The tube is hermetically sealed. M. Cadet observes, that the _prognosticator_, made in Paris many years ago, was a similar preparation.

Although, according to Cadet, this contrivance cannot be depended upon, as the appearances it presents are not regular; yet, as the effect is produced by heat, as well as light and electricity, the following summary may be added:

1. In fair weather, the composition remains at the bottom, and the liquor is clear.

2. Before rain, it will rise a little; the liquor will be clear, having merely a star floating in it.

3. Before a storm, it will rise to the surface, the liquor will appear troubled. These appearances may be seen 24 hours before the change in the weather takes place.

4. In winter, it is higher than common. During a snow, it will be very white, and pieces are seen in motion.

5. In settled weather in summer, and when warm, the composition will be low.

6. To know from what quarter wind will come, the composition will remain attached on the opposite side of the bottle to that from which it is expected.

Camphor has been burnt, like ether and alcohol, by platinum wire, previously heated. Dr. Ure observes, that a cylinder of camphor may be used for both wick and spirit, in the aphlogistic lamp; and the ignition is very bright, while an odoriferous vapour is exhaled. By adding various essential oils in small quantities to the alcohol of the lamp, various _aromas_ may be made to perfume the air of an apartment. See _Scented Fires for rooms_.

Camphor is employed in those fire-works chiefly, which are exhibited in rooms; its expense being an objection to its use in large exhibitions. In what are termed perfumed pastes, or mixtures, scented fire, or odoriferous fire-works, it is used in abundance: in fact, it enters into nearly all the compositions of this kind. Camphor, besides producing, alone, a white flame, gives a brilliant light, and, when mixed with other substances, adds greatly to the appearance of the flame; and, giving out a powerful odour, destroys, in a measure, the disagreeable smell arising from the combustion of the sulphur and nitre.

By referring to the article on Greek fire, and some incendiary preparations used in war, it will be seen, that camphor is an important constituent. As camphor is very combustible, and will even burn on the surface of water, it is well adapted for all those purposes. We have already spoken of the Greek fire; and it seems, that the peculiar character of that fire, of burning in water, was owing to the presence of camphor. This opinion appears plausible, when we consider, that some preparations _have been_ made with camphor, which had the property of burning on water.

Camphor may be pulverized by the assistance of, and brought into intimate mixture with, nitre and sulphur; because the former, in particular, tends to divide it. But it may be pulverized separately, and afterwards added to the composition, by rubbing it in a mortar with a small quantity of alcohol, or spirit of wine; or, if this cannot be had, with fourth proof brandy. As camphor is very inflammable, its effects, when mixed with saltpetre and fired, are much the same as those produced by other resins, or concrete oils. A combustion, more or less rapid, ensues, and, while the nitre itself is decomposed, the camphor also undergoes the same change, producing both water and carbonic acid, from the union of two of its elements, the hydrogen and carbon, with the oxygen of the nitric acid. In all cases, in which camphor is employed in artificial fire-works, although its own flame is _white_, it may assist in increasing the flame, which, however, is modified, according to the substances, which enter into the composition. These may not retard its combustion, but, nevertheless, may change the appearance of the flame; as is the case, when we employ the filings of iron, steel, brass, or zinc, sal ammoniac, rosin, saw-dust, and other substances, which usually form a part of such mixtures. Upon the whole, then, we may consider, that camphor acts in fire-works; 1st, as an inflammable body; 2ndly, that, besides being in a great measure decomposed, a portion of it is evaporated, and communicates, to the surrounding atmosphere, a peculiar smell, which is recognised in the odoriferous fire-works; 3rdly, that, while it acts in taking a part of the oxygen from the nitric acid of the nitre, it assists in the decomposition of this salt, more especially if it be mixed separately with the nitre; 4thly, that, in all instances of its combustion, while it acts primarily on the nitre, with the oxygen of which it forms both water and carbonic acid, it, at the same time, increases the flame, which may be either white, red, or yellow, according to the other substances employed; and, finally, it may be thrown out in the state of combustion, and receive, for the further support of its combustion, the oxygen of the air, and hence produce a white exterior flame, while that in the immediate vicinity of the composition may be more or less coloured. But its application, the proportions in which it is used, as well as the kind of fire-works to which it is applicable, will be considered at large in other parts of the work.

The great inflammability of camphor is to be ascribed to its containing a _large_ quantity of carbon and hydrogen, and a _small_ quantity of oxygen.

There is a preparation, called artificial camphor, that is formed by passing muriatic acid gas through spirit of turpentine. It inflames with facility, and burns, without leaving any residue. Might not this preparation be economically employed, in lieu of camphor, for incendiary fire-works?

_Sect. XVI. Of Gum Benzoin, and Benzoic acid._

Gum Benzoin, or Benjamin, is considered a solid balsam, and is the production of a tree, which grows in Sumatra, &c. called the _styrax benzoe_. It is obtained from this tree by incision, a tree yielding three or four pounds. It is a brittle substance, sometimes in the form of yellowish-white tears and called, from that circumstance, almond benzoin. Besides a resinous substance, it contains an acid, called the benzoic or _flowers of benzoin_, a substance similar to balsam of Peru, being a peculiar aromatic principle, soluble in alcohol and water. By heating it, or by combustion, it evolves a very agreeable smell, and is, therefore, used in those fire-works which are exhibited in rooms, theatres, &c. and also in the composition of odoriferous fire-works. Besides being in itself inflammable, it produces a peculiar smell, arising, in all probability, from an essential oil, aided, in some degree, by the separation of benzoic acid.

It has been examined by Bucholz and Brande. Its general properties are: that it is insoluble in water, although hot water takes up a part of it, said to be the benzoic acid. It is soluble in alcohol, from which it is separated by muriatic and acetic acids, but not by the alkalies. It is also soluble in ether.

The benzoic acid, or flowers of benzoin, are obtained from it by sublimation. A quantity of the powdered gum, put into an earthen basin, a thick paper cone being tied round the rim, and heat applied, the acid will leave the resin, and be condensed on the inner side of the cone. Bucholz (_Bulletin de Pharmacie_, v. p. 177) has given a process for obtaining it by means of alcohol, and some others have been adopted. By boiling four ounces of the gum in powder in a sufficient quantity of water, with three drachms of carbonate of soda, the acid will unite with the alkali, and form a benzoate of soda, which, when filtered and decomposed by sulphuric acid, will yield the benzoic acid. Five drachms of acid will be thus obtained. Lime has been used in the same manner as soda, and the acid separated by the addition of muriatic acid.

Flowers of benzoin may be used in the place of the gum; using, however, but a small quantity. They will communicate the same odour to fire as the benzoin. The flowers, or acid of benzoin, are so inflammable, as to burn, with a clear yellow flame, without the assistance of a wick. It is soluble in ardent spirits, in oils, and in melted tallow. The compounds, which it forms with them, are also inflammable. Benzoic acid is considered to be an oily acid, and contains, no doubt, a very large proportion of hydrogen.

_Sect. XVII. Of Storax Calamite._

Storax is the most fragrant of all the balsams. It is afforded by the _styrax officinalis_, a tree which grows in the Levant. It is sometimes in red tears. Common storax is in large cakes, and brittle and soft to the touch. This is more fragrant than the other sort, but is frequently adulterated with saw-dust. It is soluble in alcohol, and is said to yield some benzoic acid.

Styrax is a different substance; a semi-liquid juice obtained from the _liquidambar styraciflua_. Its odour is less agreeable than that of storax calamite. It is used in odoriferous fire, in _pastes_, in the composition for _scented vases_, and the like.

_Sect. XVIII. Of Essential Oils._

Essential or volatile oils, as well as the raspings of red cedar, dried rosemary, and other fragrant plants, are all used in the preparation of odoriferous fire. In some preparations, the _oil of roses_ is employed; in others, the essence of bergamot, of lemon, &c. which, being very volatile, evaporate in a moderate heat, and, being also inflammable, may assist in the combustion. In the case of the raspings of cedar in particular, it also communicates a peculiar appearance to the flame.

Oils, whether essential or fixed, when passed through ignited tubes, are decomposed, and furnish an inflammable gas called olefiant gas. Wax, tallow, &c. produce the same gas, the hydroguret of carbon. Messrs. Taylor and Martineau contrived an ingenious apparatus for generating gas from oil on the great scale, as a substitute for candles, lamps, and coal gas, it being much preferable for burning, as it contains no sulphur, and does not injure furniture, books, plate, paint, &c. Oil gas contains more hydroguret of carbon than coal gas, which is a great advantage, enabling one cubic foot of oil gas to go as far as four of coal gas. An elegant apparatus was erected by Taylor and Martineau at the Apothecaries' Hall, London, a drawing of which may be seen in the 15th number of the "_Journal of Science and the Arts_."

It is to be observed, that odoriferous fire-works are intended for exhibition in close apartments; so that the smell of certain gases, produced by the nitre, charcoal, and sulphur, according to the preparation used, will be more or less destroyed. Such preparations are, nevertheless, expensive, and for that reason seldom used.

_Sect. XIX. Of Mastich._

This resin, obtained, from the _pistacia lentiscus_, by making transverse incisions in the tree, is first in a fluid state, and gradually concretes into yellowish semi-transparent brittle grains. In Turkey, great quantities of it are used for sweetening the breath, and strengthening the gums. It is from the use of the resin as a _masticatory_, that its name is said to be derived. It is not completely soluble in alcohol, a soft elastic substance separating from the solution. When exposed to heat, it melts, and exhales a fragrant odour: for which reason, principally, it enters into the composition of some fire-works, as the _scented paste_. In ordinary fumigations, mastich is commonly used.

_Sect. XX. Of Copal._

Gum copal, by which name it is known, is a resin, obtained from a tree, called _thus copallinum_. It is often in the form of a beautiful white resin; but sometimes it is more or less coloured. It is frequently opaque. It may be dissolved in alcohol, spirit of turpentine, and oils, by a peculiar management, (by using camphor, previously melting it, and the like,) and then it forms the various copal varnishes, which are more or less perfect, as the copal is transparent, and the solution properly formed. When heated, it melts like other resins, and in this, and many other properties, it partakes of the character of resins in general. It is used in some of the formulæ for fire-works.

_Sect. XXI. Of Myrrh._

Myrrh is obtained from a plant, supposed to belong to the genus _mimosa_, which, as Bruce informs us, (_Travels, &c._) grows in Abyssinia and Arabia. It is in the form of tears, of a reddish-yellow colour; sometimes transparent, and at other times opaque. It possesses a peculiar odour, and a bitter and aromatic taste. It burns with difficulty, and does not melt when heated. With water, it forms a yellow opaque mixture. It dissolves in alcohol, and the solution is decomposed by the addition of water, the whole becoming opaque. According to Braconnot, myrrh is composed of 23 resin, and 77 gum, in the 100 parts. Pelletier, whose analysis differs from Braconnot's, observes, that, besides resin, it contains some volatile oil, to which, no doubt, its fragrance is owing. The gum, extracted from it, had the character common to all gums, with the exception, that, instead of forming the mucous or saclactic acid, by the action of nitric acid, it produced only oxalic acid.

That myrrh burns with difficulty, is owing entirely to the presence of so much gum, and, comparatively speaking, the small quantity of resin, which enters into its composition. But, notwithstanding this property, as it partakes of a fragrant oil, it is used in some compositions for fire-works. The gummy part may retard, as is sometimes required in particular preparations, the rapidity of the combustion, and therefore have a two-fold effect when employed in fire-works.

_Sect. XXII. Of Sugar._

Refined sugar is sometimes used in pyrotechno-mixtures. As it is a vegetable oxide, (composed of carbon, hydrogen, and oxygen), which is decomposed by heat, and has the property of decomposing nitric acid, and some of its combinations; its operation in such mixtures may be readily perceived. We have seen, when treating of chlorate of potassa, that, when this salt and sugar are mixed together, and sulphuric acid poured on the mixture, a rapid combustion ensues, which is owing as well to the decomposition of the sugar, as to that of the salt. The matches, likewise, which inflame by immersion in sulphuric acid, are covered with a similar mixture. That sugar, therefore, has the property of decomposing those salts, which are composed of acids, that have their oxygen but feebly combined, and thereby producing combustion, according to the temperature employed, or other agents made use of, is evident from a variety of experiments. By its action, then, in such cases, the products of combustion, arising from the elementary parts of the sugar alone, uniting with oxygen, must be carbonic acid and water. Sugar, submitted to destructive distillation, affords a variety of new substances; among which we may notice _caromel_, or that peculiar odour, which is recognised in the burning of sugar. Sugar may, therefore, besides assisting in part in the decomposition of saline bodies, and particularly nitre, and perhaps giving rise to new products, with which we are unacquainted, have another effect, that of destroying the offensive smell of other substances, by means of the caromel formed. Sugar, also, when mixed with various bodies, and struck with a hammer, will produce detonations.

Sugar, when used in compositions of fire, should be pure; and it may be known to be so, by producing invariably a phosphorescence in the dark, when two pieces are rubbed together. At a red heat, it bursts into flame with a kind of explosion. This flame is white, with blue edges.

Sugar is obtained from the sugar-cane; from the sap of the sugar-maple; from beets and grapes; and from various other saccharine bodies. It is formed also artificially, by the action of sulphuric acid on starch.

Mr. Kirchoff, a Russian chemist, accidentally discovered that starch may be changed into sugar by diluted sulphuric acid. One hundred parts of starch yield one hundred and ten of sugar. It appears, that, by the abstraction of a little hydrogen and carbon, starch will be converted into sugar. Potatoes, digested with diluted sulphuric acid, Dr. Ure found, would also form sugar, and very abundantly. The sulphuric acid may be removed by the addition of chalk, and, as the sulphate of lime is but slightly soluble, the pure saccharine fluid may be obtained by filtration. The sugar is procured in a solid state by evaporation, and may be clarified like other sugar. Dr. Ure observes, that good beer has been made from starch-sugar, but recommends potato-sugar. To obtain the latter, the potatoes are washed, grated down, and treated with the dilute acid for a day or two, at a temperature of 212°.

The observations of Braconnot are interesting. He has succeeded in converting a variety of vegetable substances into gum and sugar. The conversion of wood into sugar, however remarkable it may seem, has been effected; and a pound weight of rags will, by the same process, make more than a pound weight of sugar. Rice, as it contains a large quantity of fecula, may, we have no doubt, be converted, in the same manner, into saccharine matter.

When sugar is first obtained, it is impure, containing a variety of foreign substances, and more or less brown, as the Muscovado of the West India islands. It is refined, and formed into loaves, by treating its solution in water with bullocks' blood, the serum of which coagulates by heat; and, finally, by pouring the sugar, when sufficiently boiled, into conical earthen moulds, where it concretes. It is clayed, by putting a mixture of white clay and water on the sugar in each of the cones; the water from which passes through, and renders it beautifully white. The same process may be repeated; hence the single and double refined sugar. The molasses passes out from the sugar at the apex of the cone, and is received in vessels.

From twenty to thirty-five per cent. of molasses are separated in the refining of raw sugars; and it is supposed, that a considerable part of it, probably two-thirds, are formed by the high heat used in the concentration of the sirup. In order to prevent so great a quantity of molasses, different plans have been recommended. That of Howard is highly spoken of. It consists in surrounding the sugar-boiler with oil or steam at a high temperature, instead of exposing it, as heretofore, or the mode usually adopted, to the naked fire. The boiler is covered at top, and, by means of an air-pump, the air is exhausted, and the pressure of the atmosphere being removed, ebullition takes place at a lower temperature. No blood is used in Mr. H.'s process, instead of which, the clarification is performed by means of canvass filters, adding previously a pasty mixture of gypsum and alumina, made by saturating a solution of alum with quicklime. He does not employ clay, as is done in whitening the sugar; but, in its place, makes use of very pure saturated sirup. He uses animal charcoal, (bone black), which has the property of destroying vegetable colouring matter. Wilson's process for refining sugar possesses some advantages. It will be found in the 34th volume of the _Repertory of Arts_. The patent filtering apparatus of Sutherland is highly approved.

The chemical properties of sugar are the following: It is very soluble in water, both hot and cold; it forms with water a sirup, which on standing will crystallize, forming the candied sugar. It is not acted upon by oxygen gas. It is capable of combining with, and, according to some chemists, of neutralizing acids and alkalies. It is decomposed by nitric acid with effervescence, being converted into oxalic and malic acids. Tartaric, acetic, and oxalic acids prevent it from crystallizing. It unites with lime and strontian, but is partially decomposed by barytes. It combines also with oxide of lead, which it precipitates from its solution, forming, as it is called, a saccharate of lead. Alcohol has some action on it, and also hydrosulphurets, sulphurets, and phosphurets of alkalies and alkaline earths. On the application of heat, it melts, swells, becomes brownish-black, and exhales a peculiar odour, which we have mentioned, and, at a red heat, takes fire. Lastly, though possessed of some general and specific characters, it differs, in some of its properties, according to the substance from which it is obtained.

_Sect. XXIII. Of Sal Prunelle._

This salt is nothing more than nitrate of potassa, melted in a crucible, and poured into moulds, whence it receives the form under which it is found in the shops. The saltpetre, when merely fused, is not decomposed, as it is when exposed to a red heat in an iron retort. In the former case, the water only which it contains is separated; but, in the latter, the salt itself is decomposed, and oxygen gas evolved. Sal prunelle, therefore, is fused saltpetre. Combustible bodies, as charcoal, sulphur, phosphorus, oils, resins, &c. have the same effect on it as on ordinary nitre. The only advantage it has over the common refined saltpetre, in the preparation of some fire-works, is, that it is free from water, and more readily acted on by combustible substances. In preparing it, care must be taken in the application of the heat; which, if too powerful, would, besides fusing it, decompose, and convert it into nitrite of potassa. It may be readily pulverized and sifted. For the properties of _nitre_, see that article.

_Sect. XXIV. Of Alcohol._

Alcohol, or rectified spirit of wine, is used for a variety of purposes in pyrotechny, and, when it cannot be procured, strong brandy is substituted. In assisting the pulverization of some substances, as camphor, in forming the mixture of certain pastes, and in acting as a vehicle for the intimate union of some bodies, it is considered a necessary article. Alcohol may be made to form variously coloured flames, by mixing with it certain saline substances. Thus, boracic acid will form a green flame; muriate of strontian, a carmine red; muriate of lime, an orange; nitrate of copper, an emerald green; nitre, common salt, and corrosive sublimate, a yellow, &c. As alcohol has the property of dissolving essential oils, camphor, &c. it may be used as a menstruum for certain oils in the preparation of odoriferous fire-works. See _Articles on coloured flame, and odoriferous fire_.

Alcohol constitutes a part of all ardent spirits, wine, cider, beer, &c. in which it is combined with water, or with water and mucilaginous and colouring matter. It is formed in the vinous fermentation, and always results from the union of carbon and hydrogen. During the process, carbonic acid gas is liberated. Fermented liquors, therefore, or those which have passed through the vinous fermentation, always contain alcohol in more or less abundance, but mixed with water in many instances. In some it is accompanied with water, and saccharine, mucilaginous, and extractive matter. The different kinds of beer is an example of this fact. When liquors, which contain spirit, are submitted to distillation, the product is alcohol and water; for the volatile parts evaporate, and the fixed substances remain in the still. The spirit partakes, more or less, of a peculiar taste and flavour, by which liquors are distinguished from each other. On this subject, however, it will be sufficient to add, that brandy is procured by the distillation of wine; rum, from the fermented juice of the sugar-cane; gin, from fermented grain and juniper-berry; whiskey, from the fermented mash of grain, cider, &c. and, generally, the ardent liquors, from pears, peaches, and other substances, by the same process.

Alcohol, therefore, exists in all these distilled liquors, in a greater or smaller quantity, combined with water; and the proportion it bears to the water is known by a standard, as either proof, above proof, or under proof, according as its strength is shown by the hydrometer.

The process of obtaining alcohol in a pure state, (usually called rectified spirit of wine), by which the water is separated from the alcohol, consists in repeated distillations, either alone, or mixed with certain substances, which have the property of uniting with, and keeping down the water, in the act of distillation. These substances are usually potash, and dry muriate of lime, both of which substances have a great affinity for water. The specific gravity of highly concentrated alcohol, at 60° is .820, but that of common alcohol, only .837, at the same temperature.

The properties of alcohol are the following: It is a transparent liquor of an agreeable flavour, and may be changed in this particular, by essential oils. It may be exposed to a low temperature without freezing. It boils at 106°, when of the specific gravity .820, and in a vacuum at 56°. It has a strong affinity for water, with which it combines in any proportion; and the specific gravity varies according to the proportion of the mixture and the temperature, on which are founded the tables of Blagden, Gilpin, and others.

Neither common air, nor oxygen, has any action on alcohol at moderate temperatures, whether in a liquid or aeriform state. On hydrogen, carbon, and charcoal, it has little or no action, but on phosphorus it acts, a portion of which it dissolves. With sulphur, it may be made to unite, as also with the alkalies, but not with the earths, except strontian and barytes. It is decomposed by sulphuric and nitric acids, with both of which it forms ether. It dissolves some salts, and has scarcely any effect upon others. Lastly, it dissolves resins and essential oils; but it neither acts upon gums, properly so called, nor on fixed oils. It is a compound of hydrogen, carbon, and a small proportion of oxygen, and may be decomposed, by passing its vapour through an ignited porcelain tube.

Alcohol, by its combustion, as it is used in spirit-lamps for chemical and other purposes, produces no smoke, in consequence of the carbon it contains being totally converted, during that process, into carbonic acid; and its hydrogen, uniting with another portion of the oxygen of the atmospheric air, passes off in the form of aqueous vapour. Alcohol, used in this way, is preferable to oil; for the latter produces a large quantity of smoke, unless it is burnt in the Argand lamp. Alcohol is inflamed, when it is brought in contact with an ignited body. The combustion is rapid without any residue, and the flame white.

As to the strength of alcohol, the best means of determining it, is with the hydrometer; but usually its _proof_ is ascertained by means of gunpowder. A portion of powder, put into a cup, and alcohol poured on it and inflamed, will, if the latter be strong, be set on fire; if, however, the powder should not take fire, but the flame of the alcohol be extinguished, we infer the existence of water, and that the alcohol is not of the proper strength. This experiment is founded on this circumstance, that, if the alcohol contains water, after the alcoholic portion is all consumed, the water will not only extinguish the flame, but also prevent the inflammation of the powder. The hydrometer, however, is the best experiment, as it determines at once the fact of the _strength_ of the liquor.

Alcohol is used in the preparation of certain fulminating substances, as fulminating mercury and silver in particular; the preparation of which, we will give in the two next sections.

It may not be improper to mention another application of alcohol, that of forming the _aphlogistic lamp_, or lamp that burns without flame. The following description of it, is given by Accum, in his _Chemical Amusements_, Am. Ed. p. 355. "In a common lamp, with a wick of about half a dozen common threads of cotton wick, used for lamps, put some good spirit of wine. Dispose the threads of wick, not intertwined, but straight and parallel to each other. Take platina wire of the thickness of 1/100th part of an inch; coil it round the wick, about nine coils below, and six coils standing above the top of the wick; the diameter or width of the coils should not be more than 3/20th, or 1/7th of an inch wide. Light the wick; and, when the coil of platina above the wick is red-hot, blow out the flame. There will then be a current of pure alcohol, gradually rising from the reservoir below, through the wick, sufficient to keep the upper coil of platina red-hot, until the whole of the alcohol is consumed. This lamp has kept constantly lighted during sixty hours. By means of it, a match, a bit of spunk, or candle may be lighted when wanted. The quantity of alcohol consumed is not much: about an ounce, or an ounce and a half during the night, from bed-time until morning will suffice." This article was added to Accum by Dr. Cooper. A figure of the lamp is in Brande's Chemistry. Dr. Comstock has a paper on the aphlogistic or flameless lamp, in Vol. IV. p. 328, of Silliman's _Journal of Science and Arts_, which contains some judicious and useful remarks. Sir H. Davy (_Journal of the Royal Institution_) has discovered, that the vapour of camphor answers the same purpose as alcohol. If a platinum wire be heated and laid upon camphor, it will continue to glow as long as any remains, and the wire will frequently light it up into flame. Davy found, that, in the slow combustion of alcohol, &c. an acid was generated, to which he gave the name of Lampic acid. Faraday and Daniel (_Journal of Science and the Arts_) have confirmed his conclusions.

Dr. Marcet has proposed a method of producing an intense heat, by causing a current of oxygen gas to pass through the flame of alcohol. The construction of the lamp and gas-holder may be found in the _Archives des Découvertes_, Vol. vii, p. 61.

_Sect. XXV. Of Fulminating Mercury._

As the fulminating mercury of Howard consists principally of the oxalate of mercury, the oxalate of this metal may be employed for the same purpose. Oxalic acid does not act on mercury, but dissolves its oxide, and forms with it a white powder. I formed various fulminating metallic powders, (_See Coxe's Medical Museum_), and prepared one in particular by merely digesting a solution of the salt of sorrel (superoxalate of potassa) on red precipitate. The effect is that the oxalic acid unites with the oxide of mercury, and forms an oxalate of mercury, which, when struck with a hammer, produces a detonation. Oxalate of mercury, possessing the same effects, may be formed, very expeditiously, by pouring the oxalate, or the superoxalate of potassa into a solution of nitrate of mercury. The oxalate of mercury will be precipitated, which is to be caught on a filter, washed, and dried in a gentle heat.

Howard's fulminating mercury is less dangerous than either fulminating silver, or fulminating gold. The extreme force of detonation which it possesses is remarkable. The temperature required for its explosion is 360 degrees. Friction, percussion, electricity, and the flint and steel will produce this effect. It gives rise to a stunning disagreeable report, and its force is sufficient to indent both the hammer and the anvil. Four or six grains are sufficient for an experiment. It is rather singular, as Mr. Cruikshank first observed, that this powder will not inflame gunpowder; as may be shown by spreading some of the former on paper, and shaking gunpowder over it, and then firing the mercurial powder. The grains of the gunpowder may be collected entire after the explosion.

From the experiments of Howard, it appears, that this powder is composed of oxalate of mercury, and nitrous etherised gas. Fourcroy, however, has shown, that it varies in its nature, according to the mode of its preparation.

There is also a preparation of mercury, which is likewise explosive, discovered by Fourcroy. This compound may be formed by digesting the red oxide of mercury in liquid ammonia for the space of eight or ten days. The oxide assumes a white colour, and at last appears in crystalline scales. Upon ignited coals, it detonates loudly like fulminating gold, which see below. In a few days, however, it loses its fulminating property, and undergoes spontaneous decomposition. Exposed to a low heat, the ammonia is disengaged, and an oxide of mercury remains.

As ammonia forms several detonating compounds with metallic oxides, the theory of their explosive effects is the same; viz. that, while the hydrogen of the ammonia unites with the oxygen of the oxide, forming water, the azote is disengaged in the state of gas.

The process for preparing Howard's fulminating mercury is the following, dissolve one hundred grains of mercury in an ounce and a half (by measure) of common nitric acid, assisting the solution by heat. When cold, pour the solution upon two ounces (by measure) of strong alcohol, and apply a moderate heat, until the mixture begins to effervesce. A white fume then begins to undulate on the surface of the liquor, and a white powder precipitates, which is the fulminating mercury. This powder is to be immediately washed with cold water, and dried at a heat, not much exceeding that of boiling water. One hundred grains of mercury, will give, on an average, one hundred and twenty-five grains of the powder.

The products of its combustion are carbonic acid gas, azotic gas, water, and mercury. Besides by percussion, it is inflammable when brought in contact with sulphuric acid. It is supposed, that fulminating mercury sometimes contains ammonia, and that the products of combustion, according to the mode of preparation, are therefore different. The reader may consult some interesting observations on this powder in the _Journal de l'Ecole Polytechnique_.

M. Bayen, an apothecary, in 1779, (_Journal de Physique_), announced a process for preparing fulminating mercury. His process, however, is different from that described. A solution of mercury is made in nitric acid, and precipitated by caustic alkali. The precipitate (oxide of mercury) is then caught on a filter, washed, and dried. Thirty grains of this powder, mixed with four or five grains of sulphur, and struck with a heavy hammer, or heated on an iron, will explode with violence. The oxide of mercury, obtained from its solution by lime-water, has the same effect, when treated in the same manner. Another process recommended is, to precipitate a solution of the perchloride of mercury (corrosive sublimate) by lime-water, and treat the precipitate with sulphur, as above described.

_Sect. XXVI. Of Fulminating Silver._

This compound, which is more powerful than fulminating mercury, is prepared also with alcohol. Descostils (_Annales de Chimie_, LXII. p. 198,) Cruikshank, and Brugnatelli, have all written upon it.

Fulminating silver explodes without much heat. By the slightest friction it is inflamed, and detonation follows. Hence it is used in the form of toys, in fulminating balls, bombs, crackers, &c. which explode by falling on the ground. Torpedoes, pulling crackers, &c. are formed of this powder. The fulminating balls are made of glass, and contain a grain or two of fulminating silver, mixed with sand. The same mixture, put on the ends of two strips of paper, and the ends pasted, forms the pulling crackers; for the moment they are pulled asunder, the friction produced sets the fulminating silver on fire, and causes a detonation.

The same preparation placed on a wafer, and the wafer put between paper, as in the sealing of a letter, will explode, when the paper or the wafer is broken. Fulminating bombs are balls of the size of a hazle nut, containing about three grains of the fulminating silver. Their explosive effects are said to be violent. See _Detonating Works_.

This powder, in consequence of its powerful action, is dangerous; and, as it explodes so readily, it should never be put into a phial, nor should it be touched or handled in any way that can produce friction. Even when made to approach the flame of a candle, it will explode with extreme violence.

The preparation of Brugnatelli's fulminating silver consists in reducing 100 grains of nitrate of silver (lunar caustic) to powder; and, when put into a basin, pouring over it one ounce of alcohol, and the same quantity of nitric acid. The mixture will become hot, effervescence will ensue, while the whole will assume an opaque or milky appearance.

When the gray powder of the nitrate has become white, and the mixture acquires consistency, distilled water is to be added, to suspend the action. The white precipitate is then to be washed by repeated affusions of cold water, and dried in the open air, but in a dark place, so as to seclude it from the light.

In fact, this process is similar to that for preparing fulminating mercury; for it is nothing more than treating silver with nitric acid and alcohol. Cruikshank employs forty parts of silver, sixty parts of nitric acid, and sixty parts of alcohol, from which sixty parts of the powder are obtained.

Berthollet considers this powder to be composed of ammonia, and oxide of silver, and the theory of its detonation to be the same as that of fulminating gold. In its explosion, the oxygen of the oxide of silver unites with the hydrogen of the ammonia, and the nitrogen is disengaged.

Berthollet's fulminating silver, which he discovered in 1788, is another preparation, which fulminates powerfully. It is prepared by precipitating nitrate of silver by lime-water. The precipitate is placed on filtering paper, which absorbs the water, and the nitrate of lime. Pure caustic ammonia is then added, which produces an effect somewhat similar to that attending the slaking of lime. The ammonia dissolves only a part of this precipitate. It is left at rest for ten or twelve hours, and at the expiration of this time, there is formed, on the surface, a shining pellicle, which is re-dissolved with a new portion of ammonia, but which does not appear, if a sufficient quantity of ammonia has been added at the first. The liquid is then separated, and the black precipitate, found at the bottom, is put, in small quantities, on separate papers. This powder explodes even when moist, if struck with a hard body. When dry, the slightest friction will explode it. Its detonation is owing to the same cause as that producing the explosion of the other preparation of this metal, as it is also composed of oxide of silver and ammonia.