A system of pyrotechny

PART I.

CHAPTER I.

PYROTECHNY IN GENERAL.

Sec. I. Definition of Pyrotechny.

Pyrotechny is defined the doctrine of artificial fire-works, whether for war or exhibition, and is derived from the Greek, πυρ fire, and τεχνη art. In a more general sense, it comprehends the structure and use of fire-arms, and the science which teaches the management and application of fire in several operations.

Sec. II. General theory of Pyrotechny.

Combustion is either modified, retarded, or accelerated; and in consequence of the presence of certain substances, different appearances are given to flame.

The conditions necessary for combustion are, the presence of a combustible substance, of a supporter of combustion, and a certain temperature. Thus, charcoal when raised to the temperature of 800° in the open air, takes fire. This elevation of temperature enables it to act chemically on the oxygen gas of the atmosphere; the latter, as it comes in contact, being decomposed. Now, as oxygen gas is a combination of oxygen and caloric, the caloric being in a latent state, the charcoal unites with the oxygen, and the phenomena of combustion ensue; that is, an evolution of heat and light. The caloric of the decomposed gas is given out in a free state, and, according to the theory of Dr. Thomson, (Thomson's System of Chemistry, vol. i.) the light proceeds from the burning body. We have then an instance of combustion, in which there is a combustible, a supporter of combustion, and an elevated temperature. The old theory of combustion, called the Stahlian theory, which presupposes an element called phlogiston, or a principle of fire, to exist in all bodies under some modification, would explain these effects by merely supposing, that combustion was nothing more than a disengagement of phlogiston; and that when a body had lost its inflammable principle, (as a metal, when oxidized), it became dephlogisticated. But, as it proved that phlogiston is a hypothetical element, and the anti-phlogistic doctrine clearly shows, that combustion is no other than a process which unites the supporter with the combustible, forming new products; it follows, that, in all changes of the kind, the same reasoning will apply, and the same principle be tenable.

The products of combustion depend on the nature of the substance burnt, and the supporter employed. Thus, in the instance just mentioned, the charcoal, by its union with oxygen, is changed into carbonic acid, which takes the gaseous state. We say then, that carbonic acid is the product of the combustion of charcoal, or, chemically speaking, of carbon. As resins, oil, &c. contain hydrogen, as well as carbon, the products in such cases would be water, as well as carbonic acid.

The chemical effects, therefore, which we consider in fire-works, forming the basis on which a theory of sundry phenomena may be formed, are no other than the result of the action of one body on another, according to the laws which govern such action, and the consequent operation of chemical combination. Combustion, in fire-works, may be considered a primary agent in all effects which characterise artificial fire.

The second change, with respect to the appearance of the flame, the formation of stars, serpents, rain, &c. terms used in the art, is owing either to new chemical changes which the substances undergo, or to the decomposition of the products themselves. These effects, it is obvious, must be governed by the circumstances, under which the mixtures are made. Saltpetre, for instance, is the basis of fire-works, whether used in a separate state, or employed in mixture with charcoal and sulphur, as in gun-powder; and, from its composition, is adapted to all the purposes of the art, because it yields its oxygen very readily to all inflammable bodies. In consequence of the decomposition, it undergoes at an elevated temperature, when brought in contact with charcoal, sulphur, &c. and various substances which contain carbon, as pitch, rosin, turpentine, tallow, copal, and amber, combustion results, and, according to circumstances, is more or less rapid, and the flame also more or less brilliant.

When charcoal, in the state of ignition, is brought in contact with nitre, a deflagration takes place, because, at the temperature of ignition, it has the property of decomposing the nitric acid of the nitre; and as this process unites the carbon with the oxygen, in the proportion necessary to constitute carbonic acid, this acid is accordingly produced. When, therefore, we inflame a mixture of nitre, charcoal, and sulphur, or gun-powder, the whole or greater part disappears; and if we were to collect in a pneumatic apparatus, the products of the combustion, it would be found, that they are nearly altogether gaseous, and composed, as we shall speak hereafter, of sundry elastic aëriform fluids. This decomposition, the immediate effect of the charcoal on the nitric acid of the nitre, is the same as in the preceding instance, for carbonic acid gas is formed in both cases. We have then another instance of combustion, where a number of substances are concerned, and therefore, the products must be numerous.

We notice this subject more particularly, since, as in the different fire-works, nitre and inflammable bodies are used in different proportions, the result is always affected by the same laws of chemical decomposition; for the same substances, placed under similar circumstances of proportion, mixture, &c. afford the like results. If carbon alone be employed, carbonic acid gas is the result; if oil, tallow, rosin, or turpentine be used, we have then, as we had occasion to remark, water, as well as carbonic acid, by reason of the union of the hydrogen, which forms one of their constituent parts, with a part of the oxygen of the nitric acid.

Again, in a composition of mealed powder, rosin and sulphur, with or without the addition of saw dust, we infer, from the composition of the ingredients and the chemical action which subsequently takes place, that the products of combustion would be carbonic acid gas, sulphurous acid gas, water, sulphuretted hydrogen, and probably azotic, and nitric oxide gases. If the filings of steel, brass, zinc, or copper, enter into the composition, besides the products above-mentioned, there would be either an oxide of iron, an oxide of zinc, or, an oxide of copper, according as one or other of these metals are employed.

Copper, in fire-works, has the effect of communicating a green colour to the flame. M. Homberg, (Collection Acad.) observes, that the green colour in such cases is owing to the dissolution of the metal, which in fact is nothing more than the effect of its oxidizement.

The various compositions for brilliant fire, as the Chinese fire, owe their peculiar character to pulverised cast iron, and commonly to steel and iron filings. Now the effects in these cases are the same; for the same oxidizement ensues, more or less rapidly, which in fact distinguishes the kinds of brilliant fire. That of the Chinese is the most perfect, and next is the composition made with steel filings. It will be seen, however, that compositions generally are governed, in their respective appearances when inflamed, by the purity, as well as the proportion of other substances, which enter into them; and hence much of their effect depends on collateral circumstances, which we purpose to consider when we treat of the compositions individually.

That the light of certain burning bodies may be increased, is evident from these facts; and experiment has shown, that the intensity of the light of burning sulphur, hydrogen, carbonic oxide, &c. is increased by throwing into them, zinc, or its oxide, iron, and other metals, or by placing in them very fine amianthus or metallic gauze. Protochloride of copper burns with a dense red light, tinged with green and blue towards the edges. If the hydrogen of the oil acts in separating the chlorine from the copper, and the reduced copper is ignited by the charcoal, this appearance must necessarily ensue.

When solid matter is the product of combustion, as in the burning of phosphorus, zinc, iron, &c. the flame is remarked to be more intense. Flame may be modified under other circumstances, as we will have occasion to mention hereafter. When, for instance, a wire-gauze safety-lamp is made to burn in a very explosive mixture of coal gas and air, the light is very feeble and of a pale colour; but when a current of coal gas is burnt in atmospheric air, the combustion is rapid and the flame brilliant.

Dr. Ure thinks it probable, (Dictionary of Chemistry, article combustion,) that, when the colour of the flame is changed by the introduction of incombustible compounds, the effect depends on the production, and subsequent ignition or combustion of inflammable matter from them. Thus he infers, that the rose-coloured light given to flame by the compounds of strontium and calcium, and the yellow colour given by those of barium, and the green by those of boron, may depend upon a temporary production of these bases, by the inflammable matter of the flame. It is inferred also, as a probable conclusion, that the heat of flames may be actually diminished by increasing their light, (at least the heat communicable to other matter), and vice versa; because, in the most intense heat, as in the compound blow pipe, or in Newman's blow pipe apparatus, in which a mixture of oxygen and hydrogen gases is compressed, the flame, although hardly visible in bright day light, instantly fuses the most refractory bodies; but the light of solid bodies ignited in it, is so vivid as to be painful to the eye.

Some curious facts with regard to flame, in connection with electricity, are given by Brande in the Phil. Trans. for 1814. He supposes that some chemical bodies are naturally in the resinous, and others in the positive electrical state. He supposes also, as a consequence, that the positive flame will be attracted, and neutralize the negative polarity, while the negative flame will operate a similar change by inducing an equilibrium at the positive pole. Thus he found, that certain flames were attracted by the positive ball of an electrical apparatus, and others attracted by the negative ball. The flame of sulphur and phosphorus is attracted by the positive pole, and the flame of camphor, resins, and hydrogen by the negative pole.

In relation to the production of flame, we may observe, that, as sundry solid and fluid substances are inflammable, the products of combustion depend on the composition of the substance made use of, and the condition under which it is burnt. As to gaseous substances that are inflammable, the base of some gases, we may remark, as carbon and hydrogen, unite in the process of combustion with the base of other gases, (as oxygen;) and in other instances, the gas itself takes fire, and exhibits the phenomena of flame. Now carbonic acid gas extinguishes flame, although its base is inflammable; but hydrogen, as well as hydrogen gas, is inflammable, and when burnt in oxygen gas or atmospheric air produces water, which also extinguishes the flame of burning bodies.

As we will have occasion to notice a variety of aëriform fluids, especially when we treat of the aëriform products of fired gun-powder, a few remarks on this head may be useful at this time.

By the combustion of bodies, substances are generated that are either gaseous or solid, whence arises the variety of products. Of aëriform fluids, some are coloured, as nitrous acid vapour, (nitrous gas and oxygen), chlorine, and the protoxide and deutoxide of chlorine. The first is red, the rest yellowish-green, or yellowish. Some relight a taper, provided the wick remain ignited, as oxygen gas, protoxide of azote, and the oxides of chlorine. Others produce white vapours in the air, as muriatic acid, fluoboric, fluosilicic, and hydriodic. The inflammable gases, which take fire in the air by contact of the lighted taper, are hydrogen, hydroguret, and bihydroguret of carbon, carbonic oxide, prussine or cyanogen, called also carburet of azote, and phosphuretted, sulphuretted, arsenuretted, telluretted, and potassuretted hydrogen. Other gases are acid, and redden litmus, which, for that reason, are called acid gases, such as nitrous, sulphurous, muriatic, fluoboric, hydriodic, fluosilicic, chlorocarbonic, and carbonic acids; the oxides of chlorine, sulphuretted hydrogen, telluretted hydrogen, and carburet of azote. Some gases are destitute of smell, as oxygen, azote and its protoxide, and carbonic acid; while others have a strong and characteristic odour, as ammoniacal gas. Some gases are very soluble in water, and others but slightly soluble, such as fluoric, fluosilicic, carbonic, sulphurous, and muriatic acids, and ammoniacal gas. Alkaline solutions absorb some gases, as nitrous, sulphurous, muriatic, fluoboric, carbonic, hydriodic, fluosilicic, chlorine, chlorocarbonic, and the two oxides of chlorine, sulphuretted hydrogen, telluretted hydrogen, and ammonia. Alkaline gases are ammonia, and potassuretted hydrogen.

The character of gases is well defined. The compound gas of phosphorus and hydrogen takes fire spontaneously in the atmosphere, burning with a brilliant white flame; but there is another gas formed of the same substances, that does not inflame spontaneously, but is inflammable, called subphosphuretted hydrogen. This gas has a strong smell of garlic or phosphorus, and is luminous in the dark. It may be this peculiar combination, which gives rise to the ignes fatui; but the permanent ignes fatui, observed in volcanic countries, are said to be the slow combustion of sulphur, forming sulphurous acid gas. Sir H. Davy found, that phosphuretted hydrogen produced a flash of light when admitted into the best vacuum that could be made by an excellent pump of Nairn's construction.

Naphtha in contact with red hot iron glows with a lambent flame at a rarefaction of thirty times, though its flame ceases at an atmospheric rarefaction of six. Camphor ceases to burn in an air rarefied six times, but, in a glass tube which becomes ignited, the flame of camphor exists under ninefold rarefaction; whereas phosphorus, according to the experiments of Van Marum, will burn, although the atmosphere be rarefied sixty times. Hydrogen gas will burn in a rarefied air, when it is four or five times less than the pressure of the atmosphere, and its flame be extinguished, when the pressure is between seven and eight times less; from which it is inferred, that the flame is extinguished in rarefied atmospheres, only when the heat it produces is insufficient to keep up the combustion. Olefiant gas (hydroguret of carbon) ceased to burn in an atmosphere, where its pressure was diminished between ten and eleven times. The flames of alcohol and of wax taper were extinguished in an atmosphere, where pressure was five or six times less without the wire of platinum, and seven or eight times less when the wire was kept in the flame. See Flameless Lamp. Several interesting conclusions may be drawn from these facts, which, to enumerate, would lead us beyond our design. It will be sufficient, therefore, to add, that although a supporter of combustion is necessary for that process, and flame may be differently modified, yet combustion ceases if the pressure of the atmosphere be diminished in certain ratios, as already noticed.

Besides nitre, other saline substances which contain oxygen feebly combined, have been used for the same purpose. Some years ago, it was proposed to substitute the hyper-oxymuriate, now called chlorate of potassa, for nitre in the formation of gun-powder. As chlorate of potassa, when mixed with sulphur, &c. produces combustion by percussion, or by the contact of fire, this effect is attributed to the same cause,—the separation of oxygen, not from azote, but from the chlorine of the chloric acid, Hence, when that salt is used in fire-works, the result of the combustion is similar to that in which nitre is employed; at least as regards the union of the oxygen with the elementary principles of the inflammable body. On this subject, we shall make some remarks hereafter. Nitrate of soda, a salt which contains nitric acid, and similar to saltpetre in that particular, has been recommended also for fire-works. It has, however, several objections. Our object in noticing it at this time is to remark, that, when it is so employed, its effect is the same as nitrate of potassa, or saltpetre, by furnishing oxygen as the supporter of combustion. See Nitrate of Soda.

We are of opinion, that many of the nitrates might be advantageously employed in the manufacture of fire-works. Some, as nitrate of strontian, communicate a red colour to flame, as the flame of alcohol. Nitrate of lime also might be used.

All nitrates, as well as the different hyperoxymuriates, or chlorates, contain oxygen as an essential ingredient in the acid of their respective salts, which is readily given up to inflammable substances.

When nitrates are employed for fire-works, they should be free from moisture, or water of crystallization, unless otherwise required. The presence of water may, in many cases, prove injurious to the composition; and, consequently, the effect in those instances, may be influenced by this circumstance. The composition of nitric acid, and the action of carbon in the decomposition of the nitrates, or salts formed by the union of nitric acid with sundry bases, will claim our attention in the article on gun-powder.

With respect to the production of colours, some remarks on this subject may be here added.

Speaking of colours, Haüy (Elementary Treatise of Natural Philosophy, trans. ii. p. 253.) takes into view their formation according to the Newtonian doctrine; and in a note by the translator, several instances are given of the change of colour by oxidizement and other processes. Iron when exposed to heat in contact with atmospheric air gradually absorbs oxygen, and changes its colour. The colours produced depend entirely on the quantity of oxygen, and on the absorption of some of the rays of light, and the reflection of others. See Iron. The tempering of steel instruments depends on this property, and also the blueing of sword blades, and many similar operations. The first impression of fire usually developes a blue colour; a second degree produces a yellow; and, if the oxidizement augments, the iron becomes red. The major part of the metals present similar phenomena.

In vegetables, the blue colour is formed by fermentation; and many of these colours are susceptible of passing to red by a greater quantity of oxygen, as they depend on the absorption of oxygen. It is thus that the green fecula of indigo becomes blue; turnsol, red by air and acids; and the protoferrocyanate of iron, blue when exposed to the air.

When meat putrefies, the first degree of oxygenation decides the blue colour; the red soon succeeds as the process goes on. It would seem that the maximum of oxidation determines the reflection of rays of every kind, in the same proportions as subsist in solar light, of which we have many instances in combustion.

The flame of burning bodies exhibits the same phenomena. It is blue when the combination of oxygen is slow; red when it is stronger, and white when the oxygenation is complete.

These facts lead to the conclusion, that the combination of oxygen, and its proportions, give birth in bodies to the property of reflecting corresponding rays of light; but, since the combination of oxygen in different proportions ought to change the thickness and density of the component laminæ, and, consequently, to produce variations in the colours, this doctrine is not easily reconciled with the received theory.

By considering the temperature necessary to inflame different bodies; the nature of flame, and the relation between light and heat, which compose it; the caloric disengaged in a free state during the combustion of bodies, and the causes, which modify the appearance of flame,—we may be enabled to account for the phenomena already noticed. Thus, phosphorus at 150°, and sulphur at 550°, are said to take fire, and two acid products are formed; at 800°, hydrogen gas explodes with oxygen, and produces water; and, according to Ure's view, the flame of combustible bodies may in all cases be considered as the combustion of an explosive mixture of inflammable gas, or vapour, with air; and as to the change of quiescent into distributable heat, and the causes that modify combustion and flame, the facts on these heads are numerous and very important.

Sec. III. Remarks on the Nature of particular Compositions.

The spur fire, which was invented by the Chinese, but brought to perfection in Europe, is remarkably beautiful when employed in some particular parts of fire-works. This fire was so named from the effect it produces, that of forming scintillations, resembling a shower, or drops of rain, or the rowel of a spur. The artificial flower pot is formed of this fire. The stars and pinks, which it produces, are said to be brilliant. The composition of spur fire being saltpetre, lampblack, and sulphur, in the proportions we shall give hereafter, is similar in fact to that of gunpowder; for the lampblack acts in the same manner as common charcoal. As the lampblack, however, is extremely fine, and of a purer quality, its action on that account may be more powerful. While one portion of it decomposes the nitric acid of the nitre, with the oxygen of which it forms carbonic acid; another portion is thrown off in actual combustion, which puts on the appearance we have mentioned. Lampblack, it is to be observed, is a very impalpable powder, and takes fire with more facility than pulverised charcoal.

The lampblack, therefore, is consumed both by the oxygen of the nitre, and the oxygen gas furnished by the atmospheric air. With respect to the sulphur, it facilitates the combustion, as it is more readily inflamed, and it forms in the process of combustion, sulphurous acid gas. Spur fire has been improved by the addition of steel filings: They produce very brilliant scintillations, in the combustion of which, oxide of iron is formed.

With respect to the composition of rockets, the materials of which are united in different proportions, we will remark at this time, that as mealed powder, saltpetre, and charcoal constitute their principal ingredients, the chemical effect is similar to that we have stated. The combustion of such mixtures is attributed to the same cause; for whether we consider the composition of gunpowder, or the extra addition of saltpetre and charcoal, or the substitution of nitre for the gunpowder, the action must be the same, and therefore the products of combustion, similar. The action, however, as the effect evidently shows, is affected by the proportion of the substances employed, and by other circumstances which we shall notice hereafter. The different appearances, therefore, are owing entirely to the composition, as in rocket stars, rains, gerbes, tourbillons, &c.

It may appear surprising, that the combustion of gunpowder with other substances, previously well rammed in cases, as in the rocket, will give to the case a momentum of great velocity and force. This motion is regulated by the balance of the rocket; and its power depends upon the size of the case, and the compactness of the composition. There is nothing new, however, in the fact; for it is perfectly familiar with every one, if we consider the recoil of a gun when fired, the powder having a resistance to overcome, as the ball, that the explosive effect of gunpowder is equal, and that the gases produced impel on all sides. Now the effect of a ball is as the difference of its weight with the weight of the gun; while the one being so much lighter is propelled forward with great celerity, and with a corresponding projectile force, the other suffers but little motion, which we term the recoil. The combustion of the materials, of which a rocket is composed, in a case, and in many fire-works where the cases are arranged on wheels, &c. which act on the rocket-principle, produces in like manner a force proportionate to the quantity of the material employed, and the manner it is driven in the case. The force in such instances is given to the rocket by the combustible substances; and the rocket itself when free, will ascend, or move in the direction required; or if small cases are fixed on wheels, which move on an axis, they communicate motion, as in the single vertical wheels, horizontal wheels, plural wheels, and the like, and may then be considered a moving power. That rockets are used as a missile weapon is well known. They were employed by the native troops of India against the British during the siege of Seringapatam in 1799. Mr. Congreve, the inventor of the war-rocket which bears his name, may have received his first idea of using rockets from this circumstance. This rocket will be described hereafter. The projectile force of the rocket is well calculated for the conveyance of case shot to great distances; because, as it proceeds, its velocity is accelerated instead of being retarded, as happens with every other projectile, while the average velocity of the shell is greater than that of the rocket only in the ratio of 9 to 8. The basis of this increase of power in the flight of rockets, induced Congreve to make a number of experiments, which resulted in their improvement, so far as they may be used of various calibres, either for explosion or conflagration, and armed both with shells and case shot. It may be sufficient to remark, that the 32 pr. rocket carcass, which has been used in bombardment, will range 3000 yards with the same quantity of combustible matter as that contained in the ten inch spherical carcass.

M. de Buffon, (Mémoires de l'Académie, 1740,) wrote an ingenious essay on sky rockets, in which he states the appendages which may be put to them.

If we inquire into the cause of the ascension of rockets, it will appear, that this apparently extraordinary effect, as we have already remarked, is owing to the decomposition, and the consequent production and disengagement of a large quantity of gaseous fluid and caloric. The impelling power, as in the large Congreve rocket, of which we had occasion to speak, is regulated in proportion to its size, and the accuracy with which the materials have been driven.

The manner in which the flame, and, consequently, the gases are expelled from the orifice of a rocket, resembles the operation of an æolipile, which throws out the vapour of water, and sets in motion the air in its vicinity. As the more flexible must yield to the more solid body, so, in this respect, the gases produced are repelled by the air in contact with the orifice of the rocket. Thus it follows, that the rocket displaces a volume of air of a much greater weight than itself. The rocket then has upon the air, reasoning a priori, the same effect as the oars of a boat have upon water; and hence, the greater the volume of fire from the rocket, the greater is its velocity and ascent. The impelling force also increases as it consumes, being a uniformly accelerated motion.

It also appears, that a rocket sent in an horizontal direction will not pass over so great a distance, as when its motion is vertical; for, a rocket, directed in a line parallel to the horizon, passes through a medium of equal density, but if directed perpendicular to the horizon, from the moment it leaves the ground till it arrives at its greatest height, it penetrates and passes through an atmosphere whose density is continually decreasing, and consequently its impelling force meets with less resistance. But when we consider the increase of the force of the rocket, there is no comparison between that force, and the diminution of the density of the air.

From these premises it follows, that the ascension of rockets of all kinds is governed by one principle, namely, the disengagement of gaseous fluids and caloric, which displacing an equal volume of atmospheric air, operates by mutual contact.

Since, however, the air is heavier than the gases produced by the rocket, as the latter are greatly expanded, it is evident, that the gases will ascend; their specific gravity at the time of dilatation being less than that of the air.

The gases proceeding from the interior of the rocket, act therefore upon the air in the immediate vicinity of the orifice, and the rocket is consequently propelled, the stick guiding it in the direction given to it. If it were not for the rocket-stick or balance, its direction would be neither regular nor certain. Considering then, that, by the rocket-stick, the centre of gravity is changed from the rocket itself to the stick, the motion is regulated in its perpendicular flight by the stick. The rocket-stick must be always of a proportionate length and weight to the rocket.

The motion given to rockets is always to be considered, for this depends upon the direction at first imparted; but the force of ascension is regulated by the size, and other circumstances which we have mentioned.

Assuming the principle of constant force acting upon the rocket, its velocity will increase with the time, and will be as the squares of the time, according to the principles of uniform accelerated motion; but if the force varies from uniformity, then the velocity and spaces will proportionably vary.

As action and re-action must be equal, the repulsion produced by the action of the gases upon the air is equal to the force impelling the rocket. The constant action produces equal acceleration of the motion.

On the subject of the condensation and dilatation of air, and the different pressures at a mean temperature, which is more or less connected with this inquiry, the reader may consult with advantage, the work of Mr. Biot, (Traité de Physique, &c. tome i, p. 110, and 141.) The conclusions of Mr. Robins on the gaseous products of gunpowder, and the elasticity of those products, may be seen by referring to the article on gunpowder.

It must be confessed, that the theory of rockets differs in many essential particulars from that of the usual projectiles; for the motion of rockets is more complicated than that of common projectiles, and is described to partake of all the anomalies that attend the accelerated motion arising from the rocket composition, and the uniform motion of the rocket-case, after the composition is expended. It is a fact, which appears to be established, that little or no advantage has yet been gained from the experiments that have been made with cannon, even where the angle of elevation, and the initial velocity of the ball were both accurately known. It seems totally useless to look for mathematical investigations, with respect to determining the ranges, &c. of military rockets; because, if we could determine, with the greatest accuracy, the point, position, and velocity of the rocket, at the moment when the composition was expended, the remaining part of its track would still be subject to all the inequalities attending on common projectiles. During the burning of the rocket, however, its motion might, by a series of experiments, be reduced to precise rules. As the principles of gunnery, or rather of projectiles, involve a number of collateral circumstances, such as the exact momentum of any given ball when projected with a given velocity, and from a given distance, the subject is still not fully settled; but they are so far conclusive, that the resistance of the air to the same ball is as some function of the velocity. The remarks of Dr. Hutton on this head would be too lengthy. A rocket, however, is very different. The very medium, in this case, is the principal agent in producing the motion; and being enabled to ascertain all the successive energies of the propelling power, and the resisting force, we may thus far determine correctly. It is suggested, that a rocket fixed to the ballistic pendulum would determine its whole energy; but, in order to make the experiment more perfect, it is proposed to attach it to a wheel, or revolving body, and then to measure its successive energies by the motion of some weight attached to the revolving axis of the machine. It is worthy of remark, that it is impossible to accommodate or determine the motion of rockets by other projectiles; and, therefore, to ascertain their momentum, such a contrivance would be eminently useful.

Mr. Moore of the Royal Military Academy, Great Britain, (Treatise on the motion and flight of rockets,) who seems to have adopted the hypothesis of Dr. Desaguliers, respecting the momentum of the ignited composition, has given a variety of problems relative to the motion and flight of rockets in non-resisting mediums, some of which we purpose to notice.

Mariotte and Desaguliers have given two distinct theories of the motion of rockets. The latter ascribes their motion to the momentum of combustion, and the former to the elastic nature of the gaseous fluid, generated by the combustion, and the resistance of air. The observations of Desaguliers are the following: "Conceive the rocket to have no vent at the choke, and to be set on fire, the consequence will be, either that the rocket will burst in the weakest place, or if all the parts be equally strong, and be able to sustain the impulse of the flame, the rocket would burn out immoveable. Now, as the force of the flame is equable, suppose its action downwards, or that upwards, to lift 40 pounds; as these forces are equal, but their directions contrary, they will destroy each other's action. Imagine then the rocket opened at the choke; by this means, the action of the flame downwards is taken away, and there remains a force equal to forty pounds, acting upwards, to carry up the rocket and stick." This theory, however ingenious, is not altogether true; for it is asserted on the contrary, that the action of the flame or gas within the rocket, when closed, as supposed above, is conceived to arise wholly from the elastic nature of the gas, and the reaction it experiences against the ends and sides of the rocket-case; the whole of which ceases as soon as a free vent is given to the flame; and, therefore, if a rocket could be fixed in a vacuum, as the flame would, in that case, experience no resistance, there would be no reaction, and consequently, no motion would ensue. Some experiments, analogous to this position, have been made. We may merely add, with respect to Mariotte's theory, that he attributes the motion of the rocket to the resistance and reaction of the air, in consequence of which the propelling force will decrease as the velocity increases, owing to the partial vacuum left behind the rocket in its flight; so that the correct solution of the problem necessarily involves the integration of partial differences of the highest orders.

We may remark also, from the premises already established, that the first motion of the rocket, like all other motions not produced by a great momentary impulse, is slow; and before the stick is clear of the flame, gravity has been acting upon the rocket, and depressed it below its natural position, while the stick is prevented from being equally depressed, by the top of the frame; so that the angle of projection is in fact considerably less than the angle of the frame, or slope of the rocket's first position. In consequence of this, the rocket has the appearance of falling the moment after projection; and, for this reason also, the angle for producing the greatest range of a rocket exceeds very considerably that which gives the extreme range of a shell projected from a mortar. There are various propositions given by Mr. Moore respecting rockets, but to give the calculus, &c. would take up more room than we could appropriate to this abstract question. The nature of these propositions, however, may be given in a few words, viz: The strength or force of the gas from the inflamed composition of a rocket being given, as also the weight and quantity of the composition, the time of its burning, and the weight and dimensions of the case and stick, to find the height to which it will ascend, when projected perpendicularly upwards. After making the necessary calculation, he concludes by observing, that, having determined the height of the rocket, and its velocity, when the composition is just consumed, it follows that its whole height may be determined in the usual manner by the known formula, for the ascent and descent of heavy bodies. Another proposition is that of determining the path of a rocket near the earth's surface, neglecting the resistance of the air; and among others, for finding the horizontal range of a rocket, the angle of elevation, and the time the composition is on fire, being given.

The observations of Mr. Peyre, (Le Mouvement Igné,) are confined principally to the effects of gunpowder; and although applied to the use of gunpowder, and the theory of its explosive effects, yet there is nothing in immediate relation with this subject. The generation of gaseous fluid, and its impelling power, and the consequent recoil of pieces, predicated in fact on the ingenious experiments and conclusions of Mr. Robins, may furnish some data on this head. But the principles of accelerated motion, on which the effective power of war-rockets depends, this accelerated motion being no other than the acquired velocity of their recoil, necessarily involves a question of a different kind from that of common projectiles.

The caduceus rocket has not much more than half the power of ascension as the single rockets; because, being composed of two rockets placed at an angle of 90 degrees, with the usual counterpoise, (the stick), it forms in its flight a serpentine motion resembling two spiral lines, or double worm; and although by reason of the stick it ascends vertically, yet the great resistance it meets with from the air, in consequence of this motion, causes its flight to be considerably retarded.

On the contrary, when rockets are fixed one on the top of another, called towering rockets, their effect is not at all diminished; for they experience no additional resistance, as the small rocket is placed in the head of the large one; and when the latter arrives at the maximum of elevation, it communicates fire to the former, which then rises as far beyond the first, if not higher, in consequence of the pressure of the atmosphere being less, as it would, if discharged by itself on the ground. Sky rockets, however, which are merely placed on one stick, do not, unless so required, act in this manner. Although two, three, or more, may be so arranged, yet the intention is nothing more than to combine their effect, so that their tails may appear as one stream of fire. Nevertheless, they may be so arranged, as that when one is consumed, another may take its place, and produce a new volume of fire, and, in this case, they would mount to a great height.

Tourbillons, usually called the common or table tourbillons, which receive their name from the whirling motion they take in their flight, produce also, by the arrangement of their cases, and the cross stick which serves as a balance, a horizontal and rotary motion; and while one part of the fire serves to elevate them, another part, issuing in a horizontal direction, but at opposite sides and extremities, gives to the tourbillon a wheeling motion. The mosaic tourbillons are of a different kind, and intended for another effect. Tourbillons of this kind preserve a regular and constant motion.

The mosaic candle owes its effect, in a great measure, to the rocket composition. Using alternately, composition, meal-powder, and a star, ramming the composition sufficiently, but not so as to break the stars, a case is formed, the effect of which is brilliant and striking. Besides the rapid combustion of the composition, the stars, when the fire comes to the meal-powder, are thrown out by it in succession, and to the height of one hundred and more feet. We have also, in this instance, the effect of the rocket composition, and that of gunpowder; the last of which, acting in the case in the same manner as powder in a musket on a ball, throws the stars to a great height. Hence the effect is varied according to the manner of loading the case; and by employing alternately the substances we have mentioned, the effects follow in regular succession. The use of gunpowder in this manner, is strikingly shown in many other fire-works. When, for instance, stars, serpents, &c. forming the furniture of a rocket, are to be dispersed, gunpowder is put in the head or conical cap of the rocket, and fire is communicated to it at the moment the rocket has arrived at its extreme elevation. In the bursting of paper shells, the same effect ensues, and the different substances contained in the shell are dispersed in every direction.

Balloons are nothing more than shells made either of paper, or wood turned hollow. These balloons are discharged from mortars, or fire-pots, sometimes called pots of ordnance. They are merely cylinders of various diameters, made of paper and very thick, or of metal, and are furnished at their bottom with a conical cavity lined with copper, designed to hold the charge of powder. When the balloon is filled, (see Balloons), it is introduced into the mortar over the charge, and being furnished with a fuse as in other shells, takes fire the moment the powder is inflamed. According to the quantity of powder made use of, so will be the height of ascension. By determining the ascension, and the time required for the fuse to burn, and communicate fire to the shell, we may fix the precise moment for its explosion. The powder contained in the shell is sufficient only to burst it, and disperse its contents. (See Mortars, Fire-pots, and pots of Aigrette.)

A balloon will contain more stars, serpents, &c. than the head of an ordinary rocket, and the effect which they produce, must of course be more striking. The Congreve rocket, calculated as it is to convey carcass composition, balls, grenades, &c. if furnished with stars, crackers, &c. would produce an effect equal, if not superior to the balloon.

We remarked, that, in common sky rockets, the charges consist of a mixture of gunpowder, saltpetre, and charcoal, with occasionally other additions, as steel-filings. Rocket-stars, on the contrary, are usually formed of mealed powder, saltpetre, sulphur, and sometimes other substances according to the colour of the flame required. Thus, for the white star, composition oil of spike, (a preparation of Barbadoes tar, and spirit of turpentine), and camphor are employed; the camphor giving to the flame a white appearance. The blue stars owe their colour to sulphur, which is in the proportion of one to four of the meal-powder; the variegated stars have the same materials, with sulphur vivum, and camphor; and the brilliant stars, common stars, and a variety of others, we shall mention in their proper places, are all formed by the addition of sundry substances.

The variety of rains, as gold rain, silver rain, &c. are differently prepared. Besides saltpetre, meal-powder, and sulphur, gold rain contains in its composition the filings of brass, saw-dust, and pulverized glass. In this instance, the saw-dust communicates colour, while the brass and the glass are thrown out, the former partly consumed, and the latter partially fused by the intense heat. The same effect may be produced by meal-powder, saltpetre, and charcoal, or saltpetre, sulphur, antimony, brass filings, saw-dust, and pulverized glass. Here the antimony, as well as the brass, communicates the golden colour. (See antimony.) Silver rain is generally formed of saltpetre, sulphur, meal-powder, antimony, and sal prunelle, but without saw-dust; the antimony communicating silver brilliancy to the flame. It may also be formed, by employing, in given proportions, saltpetre, sulphur, and charcoal, the particular effect depending upon the proportions; or by using antimony in lieu of the charcoal, or in the place of the antimony, steel-filings. Whether antimony or steel-filings are used, the effect of their combustion is the same, forming in the one instance, an oxide of antimony, and in the other, an oxide of iron. Both gold and silver rain is employed chiefly for sky-rockets. As to the colours required, they may be formed of other substances.

The charges for water-rockets are also various. In some of which, besides the usual ingredients, (meal-powder, saltpetre, and sulphur,) sea-coal, steel-filings, saw-dust, &c. enter into their composition.

As to the different compositions, it will be sufficient to remark, that for wheels, fixed cases, sun cases, gerbes, Chinese fire, tourbillons, water balloons, water squibs, serpents, port-fires, cones, globes, air-balloon fuses, fire-pumps, and many others to be noticed hereafter, the basis of them is either gunpowder or saltpetre, and sulphur and charcoal, with or without additions. With respect to the composition of the stars of different colours, it is to be observed, that the particular colour is given by pulverized cast-iron, steel-filings, camphor, amber, antimony, perchloride of mercury, (corrosive sublimate), ivory-dust, copper, frankincense, &c. To produce tails of sparks, pitch or rosin is added. Stars which produce some sparks are usually made by using gum water in mixing the composition. The gum appears to produce a separation of the inflammable substances, and, as it is not combustible, to check, as it were, the rapidity of the combustion. In some preparations, also, isinglass or fish-glue is used in solution. This, no doubt, acts in the same manner, as well as to give firmness to the composition; but its solution is also used as a vehicle. On the same principle also, we learn the use of caustic ley, quicklime, &c. in preparing match-rope. After soaking the cord in a solution of nitre, it is afterwards dipped into ley, which is nothing more than a solution of potash rendered caustic by means of quicklime. The potash evidently checks the combustion. The formulæ for slow match, are, however, various. In the match-wood, also, prepared from the wood or bark of the linden, the wood is usually first soaked in a solution of saltpetre, and afterwards in a solution of acetate or sugar of lead, &c. For the same purpose, nitrate of copper is recommended. For stars of a yellow colour, besides gum arabic, or gum tragacanth, saltpetre, and sulphur, the addition of powdered glass, orpiment, (sulphuret of arsenic), and white amber, are occasionally made. The colour is owing to the amber and the orpiment, which have the property of communicating it to flame. We may observe, generally, that the colours produced by different compositions, is a subject of importance to the pyrotechnist. He should know the properties of each substance, and the effect of each ingredient; and, with respect to their action, be able to foretell the appearance of the flame, and other circumstances connected with the art. As a general example, we may state, that sulphur gives a blue; camphor, a white, or pale colour; saltpetre, a clear white yellow; amber, a colour inclining to yellow; muriate of ammonia, (sal ammoniac), a green; antimony, a reddish; rosin, a copper colour, and Greek pitch, a bronze, or a colour between red and yellow. In using these substances, the following remarks may be useful;—that for producing a white flame, the saltpetre should be the chief part; for blue, the sulphur; for flame inclining to red, the saltpetre should be the principal ingredient, using at the same time, antimony and pitch. (See matches of different colours, in Part ii.)

Coloured flame may be produced by various other substances, many of which are expensive, and therefore could not be employed economically. Thus, in fire-works made with hydrogen gas, or inflammable air, which have a pleasing effect, by forcing the gas, either from a bladder, oiled-silk bag, or gas-holder, through a variety of revolving jets, which are so arranged as to exhibit stars, or through pipes furnished with small apertures, &c. to resemble different standing figures,—the effect may be varied by previously mixing the gas with the vapour of ether, and other substances, which communicate to the flame, particular colours, which, in a darkened room, are extremely brilliant. Cartwright's fire-works are formed in this manner. (See fire-works with inflammable air.)

Muriate of strontian, mixed with alcohol, or spirit of wine, will give a carmine-red flame. For this experiment, one part of the muriate is added to three or four parts of alcohol. Muriate of lime produces, with alcohol, an orange-coloured flame. Nitrate of copper produces an emerald-green flame. Common salt and nitre, with alcohol, give a yellow flame. (See Illuminations and Transparencies.)

In addition to the facts already stated, it may be proper to observe, that the ingredients employed to show in sparks, which are rammed in choaked cases, are various, according to the colours required; as black, white, gray, and red. The black charges are composed of meal-powder and charcoal; the white, of saltpetre, sulphur, and charcoal; the gray, of meal powder, saltpetre, sulphur, and charcoal; and the red, of meal-powder, charcoal, and saw-dust. These are considered regular or set charges, to which we may add two others, called compound and brilliant charges. The compound charges contain a variety of substances which afford sparks; and hence, besides the usual inflammable bodies, saw-dust, antimony, steel and brass-filings, are used. The brilliant fires owe their particular effect to the presence of steel-filings, or pulverized cast-iron. Iron, in any of its states, when minutely divided, has the same effect.

Quick match is usually formed of cotton, by soaking it in a solution of nitre, and adding meal-powder. A solution of isinglass is sometimes used. The etoupille of the French is of the same nature. The manner, quick and slow match, &c. are prepared, with the various formulæ, will be considered under their respective heads. Touch paper, for capping serpents, crackers, &c. will also be noticed. The pyrotechnical spunge owes its inflammability to nitre.

In the various composition of aquatic fire-works, although more care and attention are required, it is to be observed, that, in forming water-rockets, horizontal wheels, water-mines, fire-globes, water-balloons, water-squibs, water-fire-fountains, and the like, substances are generally used along with the usual ingredients, which, under particular circumstances, may be said to repel, as well as resist the action of the water; and in this particular they resemble the celebrated Greek fire, of which we shall speak hereafter. This remark, however, applies only to certain works. After the rockets have been filled, their ends are dipped in melted rosin or sealing-wax, or secured with grease.

Fire-works, usually exhibited in rooms, are made with odoriferous gums and perfumes, and hence are called odoriferous fire-works. We may remark, that the odour or perfume is given by a variety of substances; for these, at a high temperature, are partly consumed, and partly evaporated. Thus camphor, yellow amber, flowers of benzoin, myrrh, frankincense, cedar-raspings, and the essential oils, particularly of bergamot, are employed for this purpose. Scented fire-works are of the same character. The Italians and the French, who have made more experiments in Pyrotechny, than other nations, have improved odoriferous fire-works. In these compositions, they also employ storax, calamite, gum benzoin, and other substances. Scented fire was greatly in use in Egypt, Rome, and Athens, at their fetes and public ceremonies. The unpleasant smell which gunpowder, sulphur, &c. occasion in a confined apartment, has induced the modern artificers to add sundry odoriferous substances to their pyro-mixtures. On this subject, it will be sufficient to observe, that the scented vase, which was in use at Athens, contained the following substances: storax, benzoin, frankincense, camphor, gum juniper in grains, and charcoal of the willow. It does not appear that nitre was employed. The custom of burning frankincense before the altar, is indeed very ancient; for, in the primitive temple at Jerusalem, the custom was adopted by the priests in the Sanctum Sanctorum, and is continued by the Greeks and Armenians, the Jews, the Turks, the Persians, (especially the followers of Zoroaster), preserve this custom. The Holy Fire of the latter is nothing more than the inflamed carburetted hydrogen gas, which comes from the naphtha ground at Baku.

Besides the use of nitre in pyrotechnical compositions, as it forms an essential part in all of them, there is another salt we had occasion to notice, of which an account will be given hereafter, that affords a variety of amusing experiments. This salt is the hyperoxymuriate or chlorate of potassa. Although it has neither been used for fire-works on an extensive scale, nor does it enter into any of the compositions usually made for exhibition, yet its effect is not the less amusing. Some general idea may be had of its effect, by stating a few experiments. If a mixture of this salt and white sugar be made in a mortar, and the mixture laid on a slab or tile, and a string wetted with sulphuric acid, (oil of vitriol), be brought in contact with it, or a drop or two of the acid be let fall upon it, a vivid combustion will take place. In this experiment, the acid decomposes the salt, and the oxygen unites with the carbon and hydrogen of the sugar, and forms carbonic acid and water. The same salt, rubbed in a mortar with sulphur, will produce a crackling noise resembling that of a whip; and if a mixture of the two be struck with a hammer, the percussion will cause a loud detonation. The same thing happens when phosphorus is used, but the detonation is more violent. Various other experiments may be made with it. It forms the principal part of the match, called the pocket lights. These are made, in the first place, by dipping the wood previously cut in splints in melted sulphur, and afterwards in a mixture of this salt with sugar, which is moistened with water. The match is then dried. When used, it is dipped in sulphuric acid. The red colour, usually given to the match, is formed by mixing with the composition some vermillion. Another application of the same principle, is the firing of cannon. For this purpose, after the tube is filled with powder, a covering of the same mixture is applied when mixed with water. It is then dried. When the tube is put in the vent, a drop of sulphuric acid will inflame it, and consequently discharge the gun. This salt also, when mixed with sulphur, may be used to fire fowling pieces, provided the lock be so constructed, as in a late invention, that it acts by percussion. (See Thenard's Priming powder.)

The Rev. Alexander Forsyth of Alexander Forsyth of Belhelvie, in Aberdeenshire, Scotland, took out a patent for a new kind of gun-lock, to be used without a flint, and has contrived to inflame powder merely by percussion. The powder employed for priming, consists of chlorate of potassa and sulphur. The gun-lock is calculated for firing cannon as well as musquetry; it is contrived to hold forty primings of such powder; and the act of raising the cock primes the piece. Each charge of priming is supposed to contain one-eighth of a grain of the salt. There are other substances which also produce fire by percussion. The fulminating silver, mixed with any substance, or used by itself, will detonate by percussion. It should be used with great caution. A grain or two will explode with great violence. (See Detonating Works, Waterloo crackers, &c.)

There are several other metallic preparations which detonate violently, such as the fulminating gold, fulminating mercury, &c. all of which must be used with extreme caution. (See the respective articles.)

Sec. IV. Of Illuminations.

Although nothing of much importance can be said on the subject of illumination, yet at the same time, as it is connected with some remarks we will hereafter offer, it may be proper to observe, that the practice of illuminating, as well as the exhibition of fire-works in public rejoicings, has been in use for many years. The former indeed has been customary for many centuries. We have, however, appropriated an article to the manner of forming illuminations and transparencies, and also on imitative fire-works.

Illuminations, whether with lamps, candles, flambeaux, &c. may be rendered more impressive from the manner of their arrangement. In some instances different coloured flames have been used; and the effect in this case is more grand and beautiful.

The public lighting of cities on festivals, and particularly on joyful occasions, called illuminations, is of great antiquity. Indeed, illuminations are a general expression of the public feeling, and should, on important occasions, be encouraged. Victories gained over an enemy by the army or navy are subjects of rejoicing. While, in such cases, illuminations may be viewed as an expression of the feelings of the people, they serve moreover to stimulate, in the spirit of the amor patriæ, the future actions of the patriot and the soldier; and while such rejoicings are demonstrative of victory, they are equally expressive of that virtuous feeling, of which every one must partake, on the return of an honourable peace.

What could have been more impressive than the brilliant spectacle exhibited in Paris in 1739, on the return of peace? Besides illuminations, the fire-works on that occasion were truly magnificent. The same may be said of those at Pont Neuf, and those at Versailles in the same year. We shall have occasion to speak of them, when we come to the arrangement or the order of fire-works for exhibition.

The Egyptians at an early period, made use of illuminations, and particularly at a festival, which is mentioned by the Greek authors. During the festival, as Herodotus says, lamps were placed before all the houses throughout the country, and kept burning the whole night.

During the festival of the Jews, called festum encæniorum, the feast of the Dedication of the Temple, the lamps were lighted before each of the houses, and the festival continued eight days. Illuminations were also used in Greece, according to a passage in Æschylus. When games were exhibited in the night-time at Rome, the forum was lighted. Caligula, on a similar occasion, caused the city to be illuminated. In honour of the great orator Cicero, as he was returning home at night, after the defeat of Cataline's conspiracy, lamps and torches were lighted in all the streets. Byzantium, afterwards Constantinople, was ordered to be illuminated with lamps and wax candles on an Easter eve, in the time of Constantine.

That this custom was prevalent among the christians in the first century, is evident from many authors. Professor Beckman, in his History of Inventions, vol. iii, p. 383, says, that "the fathers of the first century frequently inveigh against the christians, because, to please the heathens, they often illuminated their houses, on idolatrous festivals, in a more elegant manner than they. This they considered as a species of idolatry. That the houses of the ancients were illuminated on birth-days, by suspending lamps from chains, is too well known to require any proof."

At Damascus, the Turks always keep a lamp burning over the tomb, as it is called, of Ananias, which they much reverenced. It is said to be in the same house in which St. Paul lodged with Judas. (See Maundrel's Travels from Aleppo to Jerusalem.)

Lamps, according to Dr. Pococke, are kept continually burning in the Jewish synagogue at Old Cairo, said to have been built about sixteen hundred years ago. (See Pococke's Travels through Egypt.)

In Persia, lamps are kept burning in consequence of some religious notion, and particularly at the sepulchre of Seid Ibraham. (See Travels through Muscovy into Persia.)

A lighted lamp is frequently put up in Persia as a mark to shoot at. To be a good shot, the marksman must extinguish it. At the celebration of the feast called Ashur or Ten, from its lasting ten days, which is kept in memory of Hossein, the youngest son of Hali, the Persians make use of rags dipped in suet and naphtha, and burn them in lamps; and their courts are lighted up with thousands of lamps, the light from which is increased by as many more lanterns made of paper, that are fastened to cords drawn across the court.

The Chinese, in celebrating their solemn feasts, especially on the 15th day of the first month, called the Feast of the lanterns, from the multitude and grandeur of the lamps they exhibit in the evening, are remarkable for the splendour of their exhibitions. We are informed, (A Description of China, &c.), that many of the grandees, retrenching every year something from their tables, apparel, and equipage, to show the greater magnificence in the lanterns, used on this occasion, expend the sum of 2000 crowns. The largest are about twenty feet in diameter, and are lighted by an immense number of wax candles and lamps; but those that are most common, are of a middling size. These are generally composed of six faces, or panes, each of which has a frame of varnished wood, adorned with gildings four feet high, a foot and a half broad, covered on the inside with fine transparent silk, on which are painted flowers, trees, rocks, and sometimes human figures. The painting is very curious, the colours lively, and the wax candles give the painting a beautiful splendour. These six pannels joined together, compose a hexagon, surmounted at the extremities by six carved figures, that form its crown. Around it are hung broad strings of satin, of all colours, with other silken ornaments, that fall upon the angles without hiding the light of the pictures. The feast of the lanterns is also celebrated by bonfires and fire-works.

Candles are also used for the same purpose. Chandeliers, differently made, and holding a greater or smaller number of candles, add greatly to the effect.

The candles used by the natives of Otaheite are curiously made. According to Cooke, (First Voyage, &c.), they have candles made of a kind of oily nut, which they stick one over another upon a skewer thrust through the middle of them. The upper one being lighted, burns down to the second, at the same time consuming that part of the skewer which goes through it; the second, taking fire, burns in the same manner down to the third, and so of the rest. These candles give a tolerable light, and some of them will burn a considerable time.

The lighting of streets, Beckman considers in some respects to be a modern invention, and after quoting various authorities concludes, that, of modern cities, Paris was the first that followed the example of the ancients by lighting its streets. It appears, therefore, that the practice of illuminating was reserved by the ancients for some great occasion, that lighting of the streets was more or less partial, and confined to particular places, and that it was not general without some particular occasion called for it. (See Illuminations.)

Kircher, the German philosopher, had a wick made of amianthus, which burnt for two years without injury, and was at last destroyed by accident.[8] The Greenland stone flax, which is the same as amianthus, the Rev. Mr. Edge says is used in Greenland for lamp wicks, and burn without being in the least wasted, whilst supplied with oil or fat. Ellis (Voyage for the Discovery of a North-West Passage), found the mountain flax, (asbestus), among other minerals, on the Resolution Islands, inhabited by the Esquimaux, which is used for similar purposes. We may remark here, that the Esquimaux use stone for lamps, which they hollow out, and, according to circumstances, use also dried goose dung for wick.

Sec. V. Of some of the Feats or Performances by Fire.

We introduce this subject to show, that certain kinds of fire-works have been employed for the purpose of deceiving the ignorant, and amusing the better informed part of mankind. Many of the tricks of jugglers and slight-of-hand men, and the performances of certain rites, particularly by the ancient magi, and pagan priests, come under this head. Sundry substances, in connection with artificial fire, have been employed by persons of this description. It is true, our account of them is rather imperfect. Had the works of Celsius, which he wrote against the ancient magi, been preserved, we would, no doubt, have been better acquainted with the art of the ancient conjurors and jugglers.

Professor Beckman has endeavoured to trace the origin of the necromantic art; but although of opinion that it is very ancient, and founded in superstition and unnatural causes, he is of opinion, that the works of Celsius, which are lost, were full on the subject, and for that reason our account must be imperfect.

Plain common sense, but with enlightened reason, has alone convinced mankind of the follies of older generations, and of relying on superstitious ceremonies, or believing in miracles, exorcism, conjuration, necromancy, sorcery, or witchcraft.

The torch of reason, and experimental philosophy have dispelled the clouds of ignorance and superstition; and men, becoming more enlightened as they progress in the investigation of truth, are no longer under the influence of false doctrines, or led away by a bigoted priesthood. Philosophical experiments, the various optical illusions, the effects of electricity, magnetism, &c. are founded on immutable truths, which become the more familiar as we progress in science.

Truth, however, although elicited by the genius of great men, who have lived in every age, was suffered to be brought to the rack; because it either militated against the views of the priesthood, and enlightened the people, or curtailed the ecclesiastical power and authority of the church.

Because Anaxagoras taught that the sun and stars were not deities, but masses of corruptible matter, he was tried and condemned in Greece. Accusations of a similar nature contributed to the death of Socrates. Copernicus, in consequence of the threats of bigots and the fear of persecution, was prevented from publishing, during his life time, his discovery of the true system of the world; and it is well known, that the great Galileo was imprisoned a year, and then obliged to renounce the motion of the earth, because he asserted it. In 1742, a commentary on Newton's Principia, one of the first productions of human genius, was not allowed to be printed at Rome, in consequence of its promulgation of this doctrine; and, in the true spirit of priest-craft, the commentators were obliged to prefix to their work a declaration, that on this point, they submitted to the decisions of the supreme pontiffs! Such are the results of bigotry, ignorance, superstition, and especially of civil and ecclesiastical governments, that consider learning a curse, and ignorance a blessing! Happily for the people of the United States, their co-equal rights and enlightened reason, will ever guarantee them against tyranny on the one hand, and fanaticism on the other. Superstition has always been an engine of oppression, and wherever it prevails, the powerful are sure to make use of it to oppress and destroy the weak.

Another instance of the assumed prerogative of the holy fathers may be found in their conduct towards the house of Medici; for the pontiffs, it is known, induced the house of Medici, by granting it the cardinalship, to suppress the academy del Cimento. The reason of this step is obvious to all; for they were sensible, that, if the people became once enlightened, they would lose their weight, their influence, and authority. But as jugglers are conscious of their gross deceptions, working on the imagination and credulity of the multitude, they in this respect appear at least to know themselves. Like the juggler mentioned in Xenophon, who requested the gods to allow him to remain in places, where there was much money and abundance of simpletons, they acted as the prototype. We might enumerate, if it were not irrelevant to our subject, a number of facts concerning these impostors.[9]

The miracles wrought by Moses, as recorded in the books of Exodus, were, we have reason to believe, by the immediate command of a supreme power. When Moses had commissioned Aaron (Exodus, chap. vii, verse 9, 10, &c.) to be a prophet, Aaron took a rod and cast it before Pharaoh and his servants, and it became a serpent; but it seems, however, that Pharaoh called the wise men and the sorcerers, called the magicians of Egypt, who performed the same thing with their enchantments; "for they cast down every man his rod, and they became serpents: but Aaron's rod swallowed up their rods." It appears that on another occasion, the waters were turned into blood by smiting them with the rod; "and the magicians of Egypt did so with their enchantments." When Aaron was commanded to stretch forth his hand with his rod over the streams, &c. frogs appeared upon the land, and the magicians did so likewise; but when vermin were brought forth, by smiting the land, the magicians were unsuccessful, and said unto Pharaoh, "This is the finger of God." In the continuation of the plague, Moses and Aaron were commanded to take the ashes of the furnace, before Pharaoh, and sprinkle them up towards Heaven; and it became a hail on man and beast, but the magicians were affected, and could not stand before Moses. When Moses stretched forth his rod towards heaven "hail, and fire mingled with hail," came down; and on another occasion, they brought forth locusts. When this plague ceased, Moses caused darkness to prevail.

We will merely observe, that, with regard to the magi of Egypt, who it is known possessed all the learning of the day, and were celebrated in after ages for superior wisdom, so much so that many of the Grecians resorted there to be initiated into their mysteries,—they were of a different description from those who really worked miracles, according to divine inspiration. Hence we find, that, although distinct in their character, the magicians of Egypt pretended to perform certain rites, and to work upon the feelings of the people. Their initiary process, which the Pythagoreans in many respects pursued, and traces of which are extant in the order of free-masonry, was merely intended to preserve their knowledge within the pale of, and veiled in, hieroglyphic mystery, which none but the initiated could understand. Priestley, in his Institutes of Moses, points out the difference between the magi, so called, and the rites and ceremonies of the ancient Hebrews. But the imposition practised on mankind, even in modern times, aided by engines of the most abominable kind, as instruments of torture, in the inquisitorial tribunals of Portugal and Spain, are sufficient of themselves to call down the vengeance of impartial justice.