TRANSCRIBER'S NOTE

For consistency and clarity, a space (when absent) has been placed between the number and the unit of weight lb. and lbs. giving for example '21 lbs.' in place of '21lbs.'

Fractions, usually in the form '14 3-4' in the original text, have been converted to the form '14³/₄' in this etext.

Also, in a few larger tables with italic styling on some text, this italic styling has been removed, for consistency with the .txt version. In a few cases a word has been abbreviated to conserve table space: cal. = caliber; diam. = diameter.

Some instances of Tome in French citations have been changed to Tome (no italic), for consistency.

Some accents and spelling in French citations have been corrected.

For consistency, instances of 'fireworks' and 'fire works' have been changed to the predominant form 'fire-works'.

Obvious typographical errors and punctuation errors have been corrected after careful comparison with other occurrences within the text and consultation of external sources.

The cover image was created by the transcriber and is placed in the public domain.

More detail can be found at the [end of the book].

A
SYSTEM OF PYROTECHNY,

COMPREHENDING THE THEORY AND PRACTICE, WITH THE APPLICATION OF CHEMISTRY;

DESIGNED FOR EXHIBITION AND FOR WAR.

IN FOUR PARTS:

CONTAINING AN ACCOUNT OF THE SUBSTANCES USED IN FIRE-WORKS; THE INSTRUMENTS, UTENSILS, AND MANIPULATIONS; FIRE-WORKS FOR EXHIBITION; AND MILITARY PYROTECHNY.

ADAPTED TO THE

MILITARY AND NAVAL OFFICER, THE MAN OF SCIENCE AND ARTIFICER.

BY JAMES CUTBUSH, A.S.U.S.A.

LATE ACTING PROFESSOR OF CHEMISTRY AND MINERALOGY, IN THE UNITED STATES' MILITARY ACADEMY—MEMBER OF THE AMERICAN PHILOSOPHICAL SOCIETY—CORRESPONDING MEMBER OF THE COLUMBIAN INSTITUTE—MEMBER OF THE LINNÆAN AND AGRICULTURAL SOCIETIES OF PHILADELPHIA—LATE PRESIDENT OF THE COLUMBIAN CHEMICAL SOCIETY, AND VICE-PRESIDENT OF THE SOCIETY FOR THE PROMOTION OF A RATIONAL SYSTEM OF EDUCATION, &C. &C. &C.

PHILADELPHIA:
PUBLISHED BY CLARA F. CUTBUSH.
1825.

EASTERN DISTRICT OF PENNSYLVANIA, to wit:

BE IT Remembered, that on the ninth day of February, in the forty-ninth year of the independence of the United States of America, A. D. 1825, Clara F. Cutbush, of the said district, hath deposited in this office the title of a book, the right whereof she claims as proprietor, in the words following, to wit:

A System of Pyrotechny, comprehending the Theory and Practice, with the application of Chemistry; designed for Exhibition and for War. In four parts: containing an account of the Substances used in Fire-Works; the Instruments, Utensils, and Manipulations; Fire-Works for Exhibition; and Military Pyrotechny. Adapted to the Military and Naval Officer, the Man of Science, and Artificer. By James Cutbush, A. S. U. S. A. late Acting Professor of Chemistry and Mineralogy in the United States' Military Academy—Member of the American Philosophical Society—Corresponding Member of the Columbian Institute—Member of the Linnæan and Agricultural Societies of Philadelphia—late President of the Columbian Chemical Society, and Vice-President of the Society for the Promotion of a Rational System of Education, &c. &c. &c.

In conformity to the act of the congress of the United States, intituled "An act for the encouragement of learning, by securing the copies of maps, charts, and books, to the authors and proprietors of such copies, during the times therein mentioned."—And also to the act, entitled, "An act supplementary to an act, entitled, "An act for the encouragement of learning, by securing the copies of maps, charts, and books, to the authors and proprietors of such copies during the times therein mentioned," and extending the benefits thereof to the arts of designing, engraving, and etching historical and other prints."

D. CALDWELL,

Clerk of the Eastern District of Pennsylvania.

To the Corps of Cadets, of the United States' Military Academy, West Point;

Gentlemen,

To you, a scientific and distinguished Corps, this work on Pyrotechny is respectfully dedicated. Your liberal subscription first encouraged me to undertake its publication; for which, accept my grateful thanks.

CLARA F. CUTBUSH.

ADVERTISEMENT.

In submitting the present work to the public, it may be proper to state some of the difficulties, under which it has been published, and to bespeak an indulgent allowance for any imperfections, which may be observed in the style or arrangement. As a posthumous work, it has been deprived of those final improvements and emendations, which are generally made by Authors, while their works are in progress of publication. While, however, the work has laboured under these disadvantages, the publisher has felt it her duty to make every arrangement, to supply, as far as possible, the want of the author's personal superintendence of the publication. This course was due to the scientific reputation of her late husband, as well as to the numerous and generous patrons of the work.

Philadelphia, April, 1825.

[TABLE OF CONTENTS.]

[INTRODUCTION.]

In presenting this work to the public as a system of Pyrotechny, which, we have reason to believe, is the only full and connected system that has appeared, we may be permitted to remark, that, in our arrangement of the subject, we have appropriated separate heads for each article.

This plan, of the subject being considered in chapters and sections, and forming with the divisions of the work, a connected system of arrangement, enables the reader to have a full view of the whole, and, at the same time, all the facts in detail belonging to the chapter, or section under consideration. By referring to the Table of Contents, this plan will be seen without further comment. The arrangement of the different articles in this manner, necessarily comprehends in the onset all the substances, which are employed in various preparations. In considering this part of our subject, we have given the chemical characters, or peculiar properties of each substance respectively; by which a rationale of pyrotechnical effects may be the better understood, and, consequently, the action of bodies on each other better illustrated.

In this part we also comprehend the General Theory of Fire-works, which it may be proper to remark, we have drawn from the known effects of chemical action; so far, at least, as the laws, of affinity, which govern such action, are applicable to the subject. The importance of this inquiry, although having no relation to the mere manipulations of the artificer, can not be doubted; since a knowledge of chemistry has already improved the preparation of gunpowder, and its effects are now known to be owing to the formation of sundry elastic aeriform fluids. On this head, that of the application of chemistry to Pyrotechny, we claim so much originality, as, so far as we know, to have been the first, who applied the principles of chemistry.

It is not to be expected in every instance, that a rationale of the decomposition as it occurs, or the order in which it takes place, can be given with certainty; because, where a variety of substances enter into the same preparation, which is frequently the case, the affinities become complicated, and the laws of action for that reason indeterminate, and frequently anomalous. But, on the contrary, in a variety of primary operating causes, by which effects analogous in their nature result, decomposition of course being the same, the causes are well understood, and the effects are thereby known, and duly appreciated.

This, for instance, is the case with a mixture of nitrate of potassa, charcoal, and sulphur, in the proportion necessary to form gunpowder; for, it is known, that the explosive effects of powder are owing to the sudden production of a number of gases, which suffer dilatation by the immense quantity of caloric liberated at the moment of combustion. Although the production of caloric by the inflammation of gunpowder is a case, which cannot be explained by the present received theory of combustion, as we have noticed in that article; yet we know that it is a fact, and that caloric is generated by the decomposition of the powder.

If we consider the primary cause of this decomposition, we naturally inquire into the products of the combustion, and endeavour to account for the production of the elastic aeriform fluids. We know that carbon has the property of decomposing nitric acid, and also nitrate of potassa; for, when it is brought in contact in the state of ignition with nitre, a deflagration will ensue, and carbonic acid be formed. The quantity of this acid is in the direct ratio to the quantity of oxygen required to saturate a given quantity of carbon; and therefore, by employing certain proportions of nitre and charcoal, the latter will decompose the former, and by abstracting its oxygen, on the same principle form carbonic acid, while the azote, the other constituent of nitric acid, will be set at liberty. Nor is this all, if we consider the action of sulphur. The sulphur must unite with one portion of the oxygen to produce sulphurous acid gas, and also with the potassa of the nitre, and form a sulphuret, a compound necessary to be formed, before we can explain the production of sulphuretted hydrogen gas, which results from the decomposition of water contained in the nitre. There also results, as a product, sulphate of potassa. In considering these products at large, it would be necessary to go into detail; and, as we have descanted largely on its combustion in gunpowder, we accordingly refer the reader to the article on Gunpowder. It will be sufficient, however, to remark, that the agent, and consequently the cause, which produces the decomposition of nitrate of potassa, is carbon or charcoal. This, by uniting with the greater part of the oxygen of the nitre, produces, in a determinate proportion, carbonic acid gas. This gas, therefore, in conjunction with other gases, formed at the same time, all of which being expanded, causes what is denominated the explosive effect of gunpowder.

We have then a primary cause of the decomposition, and most of the effective force of gunpowder is owing to the carbonic acid; and it is found, that gunpowder made without sulphur is equally powerful as that with, since it adds nothing to its power.

Causes, therefore, chemically speaking, operate alike under similar circumstances. The materials made use of being equally pure, and used in the same proportion, the effect must necessarily be the same.

It is not only in the instance we have mentioned, but in every other, in which chemical action ensues, that this doctrine is tenable. We might, indeed, notice a number of cases of a similar kind; as, for instance, in the combustion of many incendiary preparations, as fire-stone, fire-rain, composition for carcasses, light-balls, and a variety of fire-works of the same kind. If we mix pitch, tar, tallow, &c. with nitrate of potassa, and burn the mixture, we have the combined action of two elementary substances, which enter into the composition of these bodies, namely, carbon and hydrogen. The products would be carbonic acid gas, and water; because the oxygen of the nitre would unite with the hydrogen, as well as the carbon. If we employ sulphur at the same time, another product would be sulphurous acid gas, and probably sulphuric acid; and if gunpowder be used, as in the fire-stone composition, then, besides these products, we would have those of the gunpowder.

As this subject, however interesting to the theoretical pyrotechnist, cannot be understood without a knowledge of chemistry, it is obvious, that that science is a powerful aid to pyrotechny. It is unnecessary to dwell on this head. We may add, nevertheless that, in order to understand the effect of all mixtures, or compositions made use of, it is necessary to consider the nature of the substances employed, and the manner in which chemical action takes place, and consequently the products, which determine in fact the characteristic property of each species of fire-work, and the phenomena on which it is predicated. All products of combustion depend on the substances thus decomposed, and by knowing the effects, we may readily refer them to their proper causes.

With respect to caloric, it may not be improper to offer some remarks.[1] The hypothetical element of phlogiston having given way to the antiphlogistic theory at present received, our ideas respecting caloric are predicated on facts. Caloric is a term, which expresses heat, or matter of heat. In pyrotechny, we have merely to consider it in a free, or uncombined state; but as the subject is interesting, we purpose to notice it very briefly under the following heads: viz. its nature; the manner it is set in motion; its tendency to a state of rest; the changes it produces on bodies; and the instruments for measuring its intensity.

As to the nature of caloric, different opinions are entertained. We know the effect of heat: if we touch a substance of a higher temperature than our bodies, we call it hot, and vice versa. The one is evidently the accession, and the other the abstraction, of caloric. The latter is merely relative as respects ourselves; for the effect depends on our feelings, and the sensation of hot or cold is therefore governed by them.[2] Caloric, however, is considered to be a substance, composed of inconceivably small particles; but count Rumford and sir H. Davy are of a contrary opinion, namely, that it depends upon a peculiar motion and not on a subtle fluid.

As the effect of caloric, according to their view, depends on motion, the agencies by which this is effected are of the first importance. That it exists in all bodies in a state of rest, and in a greater or smaller quantity, and consequently in a relative proportion, is well known, and on this, the capacities of bodies for caloric is founded. The capacities of bodies for heat are changed by various means, and caloric is put in motion; and, according to its quantity, the bodies may be either cold or hot. When the surrounding bodies become heated, they receive this caloric thus set free, and, in this view, the absolute quantity of their heat is increased. This state of rest, to which caloric is subject, may be destroyed either by an increase or a diminution of the capacity of a body. If caloric be put in motion by causes of any kind, which influence the capacities of different bodies, a theory maintained by Davy, then as the capacity for heat is changed so is free heat produced. Diminish the capacity of a body, its excess will of course be given out, and distribute itself among the surrounding bodies, which become heated; but increase the capacity, and a different effect ensues. The body absorbs caloric, by which its capacity is increased, and cold is produced. Caloric, whether considered a substance, or an attribute, possesses, nevertheless, this property, that when it is given out, as in the mixture of sulphuric acid and water, which occupies a less space than both in a separate state, the sensation of heat follows; and when it is absorbed, as in the various freezing mixtures, or in a mixture of snow and common salt, the sensation of cold is excited. The causes, however, which set caloric in motion, or that produce heat, are such as combustion, condensation, friction, chemical mixture, and the like. It is remarkable, that these effects are invariably the same, and are affected by corresponding affinities. When a piece of iron is struck with a hammer, the percussion produces a condensation of the iron, its specific gravity is increased, and the iron finally becomes ignited. The condensation of air, in the condensing syringe, will set fire to tinder. The flint and steel produce a condensation; for the metal, although small, is sent off in scintillations in the state of ignition. That caloric is contained in bodies in the state of absolute rest, and is evolved by condensation, there is no doubt. Gunpowder, by percussion, in contact with pulverized glass, is inflamed; and it appears very probable, that it also contains caloric in a state of rest. The experiments of Lavoisier and Laplace, on the quantity of caloric actually absorbed in nitric acid, and in a latent state, (noticed in the article on gunpowder), are satisfactory. If caloric is not in that state in nitre, how are we to explain the sudden transmission or evolution of caloric in fired gunpowder, where no external agent in any manner can influence the formation, or disengagement of caloric? Friction or attrition produces heat; and the distributable excess of caloric, as it is called, although not satisfactorily accounted for, may arise from a condensation; which, however, is denied.

The Esquimaux Indians kindle a fire, very expeditiously, in the following manner: They prepare two pieces of dry wood, and making a small hole in each, fit into them a little cylindrical piece of wood, round which a thong is put. Then, by pulling the ends of this thong, they whirl the cylindrical piece about with such velocity, that the motion sets the wood on fire, when lighting a little dry moss, which serves for tinder, they make as large a fire as they please; but as the little timber they have is drift wood, this fails them in the winter, and they are then obliged to make use of their lamps for the supply of their family occasions. Ellis's Voyage for the Discovery of a North-West Passage.

Friction is, therefore, one means of producing distributable heat, which is also exemplified very frequently in the axis of a carriage wheel; of mill work; in the rubbing of wood, when turned on its axis in a lathe, by which turners ornament their work with black rings; rubbing a cord very swiftly backwards and forwards against a post or tree, or letting it run over a boat, &c. as in the whale fishery; the motion of two iron plates against each other, pressing them at the same time, &c. The great object in the construction of machines is to avoid, or lessen the degree of friction. See Hatchette, Vince, and Gregory. Count Rumford (Nicholson's Journal, 4th edit. ii, 106), and professor Pictet (Essai sur le Feu, chap. ix.) have made some valuable experiments on heat evolved by friction.

The sun is one great source of caloric. In whatever mode it produces it, whether by giving it out from its own substance, by the action of light on the air that surrounds the globe; by the concentration of calorific rays by means of the atmosphere, acting as a lens; or by putting caloric in the distributable state, always pre-existing in some other, as in a state of rest, are questions, which, in our present state of knowledge, we are unable to solve. We know the fact, and that the caloric is of the same nature as that obtained by combustion.[3]

Combustion is a process by which caloric is put in a distributable state. The opinion of Stahl and others, that all combustible bodies contained a certain principle called phlogiston, to which they owed their combustibility, and that combustion was nothing more than a separation of this principle, gave rise to the phlogistic or Stahlian theory, which was afterwards modified by Dr. Priestley. But his theory is equally untenable. Kirwan's opinion was no less vague, although he substituted hydrogen for phlogiston.

The Lavoiserian, or antiphlogistic theory overturned the Stahlian. According to this theory, a combustible in burning unites with oxygen, and heat and light are given out by the gas, and not from the combustible. According to a modified theory of the above, by Dr. Thomson, caloric is evolved by the gas, and light from the burning body. Without noticing the instances, in which this theory, as a general one, is insufficient to explain the cause of combustion, or of the production of heat and light, we will merely remark, that bodies which support combustion are called supporters, as oxygen gas, chlorine gas, &c. and those, that undergo this change, are named combustible bodies.

The products of combustion may be fixed or gaseous, and either alkalies, oxides, or acids; or, when chlorine is the supporter, chlorides, &c. A few examples will be sufficient. By the combustion of metals, iron for instance, we obtain a fixed product, and in the present case an oxide of iron; by the combustion of antimony and arsenic, the antimonic and arsenic acids; by the combustion of charcoal, we have carbonic acid gas, a gaseous product; by the combustion of potassium or sodium, we obtain a fixed alkali, depending however on the quantity of oxygen; by the combustion of sulphur, phosphorus, &c. acids; and when metals are burnt in chlorine gas, chlorides are produced.

It is evident from facts, that, whatever theory may be assumed, combustion occasions the production of free caloric, or changes the condition of caloric, from quiescent to distributable heat. The conclusions drawn by Mr. Davy and others, appear to have been predicated on the absorption of the base, and development of caloric, as in oxygen gas, and the peculiar alteration in bodies implying a decrease in their capacity; and hence, as regards the products of combustion, they must necessarily possess a less capacity for heat than the mean capacity of their constituents.

Whether we regard heat as latent, in the acceptation of the term, as applied or used by Dr. Black, or quiescent, or in a state of rest, it is certainly evident, that combustion is a chemical change, and by it caloric passes from a combined to an uncombined state, and is thus made sensible, free, or thermometrical heat. Combustion may, as it certainly does, put quiescent heat in a distributable state; but this quiescent heat is the same in the present case, of which there can be no doubt, as latent caloric. The thermometer will only indicate as much caloric in the air as is in a distributable, or free state; but, if the same air be employed to supply, or support combustion, the heat, rendered appreciable by the senses and the thermometer, will be in the ratio of the decomposition of the oxygen gas of the atmosphere, and, of course, to the development of free caloric.

Chemical combination, such as occurs by the mixture of fluids, as alcohol and water, sulphuric acid and water, some of the gases, as muriatic acid gas with water, &c. evolves heat, and sometimes sufficient to boil water. In cases of spontaneous combustion, it would seem, that quiescent heat passes to the state of distributable heat; for if nitric acid, for instance, contains so large a quantity of quiescent heat, or fixed heat, as the experiments of Mr. Lavoisier make it appear, we may readily explain why spontaneous combustion ensues, when that acid is brought in contact with spirits of turpentine; because the chemical action of the acid on the carbon and hydrogen of the turpentine, which takes place, produces at the same time a corresponding change in the caloric itself, from a quiescent to a distributable state. If the same data be admissible with regard to the combination of the nitric acid with potassa, which we may judge to be the case by the experiments of Lavoisier and Laplace, (quoted in our article on Gunpowder), then, indeed, its mechanical union with charcoal, and sulphur, although in a common temperature no combustion ensues, will, at the temperature required to inflame the mixture, (about 700 degrees according to some), produce a decomposition altogether chemical; and while new products are formed, the caloric, necessary also for their generation, passes from a quiescent to a distributable state; and a portion of it goes into a new state of combination, also quiescent. We mean that portion which is necessary for the constitution of gaseous fluids. This fact is remarkable. By referring to the original state or condition of the caloric, if we admit that state in the present instance, (which appears the only mode of accounting for the emanation of free caloric by the combustion of gunpowder), it is easily perceived, that chemical changes, besides the usual supporters of combustion being concerned, as in ordinary cases of combustion, must produce a similar change in the state of combined or quiescent heat.

Predicating this opinion on the results of the experiments of MM. Lavoisier and Laplace, and seeing that gunpowder inflames per se, or without the aid of a gaseous supporter, we have no hesitation in risking it, in the present state of our knowledge concerning heat as our present belief and conviction. Although there is no satisfactory theory offered to explain all the instances of spontaneous combustion, yet it seems reasonable to conclude, that in many cases at least, that effect may take place by some chemical action, which, like the instances already quoted, may change quiescent into distributable heat. We have stated (See [Gunpowder]) some instances of spontaneous combustion, which have taken place merely in consequence of the charcoal. Some have attributed the effect to pyrophorus, and others to the presence of hydrogen in the coal, which, by absorbing and combining with oxygen and forming water, sets the caloric of the oxygen gas at liberty, and thus produces combustion. However this may be, there are other instances, that of cotton and oil, some kinds of wood, wood-ashes and oils, &c. which have produced spontaneous combustion.

We will only add, however, that until we can give a better theory, the effect in these instances may be attributed to chemical action, and with it, the change of caloric in the manner already mentioned. Chemical action in such cases appears necessary, although mechanical means, as percussion will produce heat.

Quiescent heat is also put in motion by electricity; but in what manner it acts, so as to produce that effect, is unknown. It is a powerful agent in nature, and calculated for important ends, of which we are ignorant. It is unnecessary to notice opinions concerning it. All electrics will yield it, such as glass, rosin, &c. and it may be collected in the usual manner by the prime conductor and Leyden jar. Galvanism, called also Galvanic electricity, produced by an arrangement of zinc, and copper plates in a pile, or trough, and placed in contact with some oxygenizing fluid, has the same effect of causing quiescent heat to become distributable, and is undoubtedly the result of chemical action. The peculiar character of this fluid, the nature of the two opposite poles, &c. have been, and continue to be, a subject of interest to the philosopher. The deflagrator of professor Hare of Philadelphia is an apparatus well calculated for many interesting experiments on galvanism. To that gentleman, we are also indebted for the compound blowpipe, which produces a very intense heat by the combustion of hydrogen in contact with oxygen gas. Notwithstanding professor Clark of England has laid claim to the apparatus, and the use of hydrogen gas in this way, the merit of the discovery is due to our learned and ingenious countryman.

Since heat is put in motion as a consequence of the increased capacity of a body, and, by combining with a substance whose capacity has been increased, becomes by degrees quiescent, according to the respective capacities of bodies; cold is an effect, which is occasioned by this change from a free to a combined or quiescent state. The absorption of heat, necessary for the generation of cold, if so we may consider it, takes place in every instance, where that effect is observed. The heat of surrounding bodies, in a distributable state, is now no longer characterised as such; and the consequence is, therefore, that that particular sensation, or effect follows.

Cold may be produced by saline mixtures, the salts for which having their full quantum of the water of crystallization; and by the evaporation of fluids, as water, alcohol and ether. In the one case, that of the freezing mixtures, we have seen, that the effect is produced by the absorption of heat; and with regard to the cold produced by fluids, even in vacuo, (where the effect is more instantaneous), the cause is attributable to evaporation; for the fluid changes from a liquid to an aeriform state, and during this transition robs the body, with which it was in contact, of a part of its caloric, and thereby reduces its temperature. Artificial ice is made on this principle.

The next subject with regard to heat, is the different modes in which it tends to a state of rest. There are some facts in relation to this subject worthy of notice; and particularly, that, in the tendency of caloric to become quiescent, after having been put in motion, bodies often increase in temperature. This tendency to a state of rest is effected either by the conducting power of bodies, or radiation. Heat radiates in all directions, and in quantities, according to the experiments of Leslie, more or less variable, which depend on the nature of the radiating surface. Hence that power, which bodies possess, called the radiating power, varies in different substances. Thus, the radiating power of lampblack is 100, while gold, silver, copper, and tin plate are 12, from which it appears that the metals distribute less heat by radiation. That caloric obeys the same laws as light, is obvious from Pictet's experiments with concave mirrors, where the calorific rays move in the same order, the angle of incidence being equal to the angle of reflection. It is also refracted; hence the concentration of the solar rays in a focus by the burning glass. Various experiments have been made with mirrors, and concave reflectors. The effect of the former in destroying the fleet before Syracuse, an experiment made by Archimedes, is a fact well authenticated in history. Concave reflectors have inflamed gunpowder. This subject, however, is noticed at large, when speaking of mirrors as an incendiary in war.

That bodies conduct heat, and with different degrees of power, so that some are called good and others bad conductors, is well known. This property depends on the quantity of caloric, which a body receives, before it changes its state. Metals are considered good conductors, and glass, charcoal, feathers, &c. bad conductors. Hence bad conductors, as wool, &c. preserve the temperature of the body, or keep it warm in winter; and snow, for the same reason, prevents the action of intense cold on the ground. Liquids also conduct heat. Whether we consider caloric in this case carried, or transported, as it is more properly defined, the fact may be shown by several experiments. Ebullition, or boiling, is a phenomenon, which depends on the increment of temperature; for as water, for instance, receives caloric, until the thermometer indicates 212 degrees, the boiling point, mere evaporation ensues; but that temperature, under the usual pressure of the atmosphere, causes the formation of bubbles at the bottom of the vessel, as that part receives the degree of heat necessary for ebullition before any other; and these bubbles, as they form, rise in succession, and pass off in the state of steam, while the circumjacent fluid takes its place, and the process continues till all is boiled away. Water, when it passes off in the state of steam, which requires a degree of heat equal to 212 degrees of Fahrenheit, receives also 1000 degrees of non-distributable caloric, or latent heat; and however singular the fact may appear, the wise Author of Nature, it seems, has reserved a store of caloric, in this form, ready to be put in requisition, when necessity demands it, in a distributable shape.

Caloric, when in a state of rest, exists in different proportions, and although the actual temperature may be the same, yet the quantity of caloric in a quiescent state may be variable. There are several experiments, which are adduced to illustrate this fact. It results from experiment, that bodies receive heat according to their several capacities for it; hence, when any number of bodies are differently heated, the caloric, which becomes latent, does not distribute itself in equal quantities, but in various proportions, according, as we remarked, to their several capacities. Caloric, therefore, in a state of rest, is in relative quantities; and as the capacity of bodies for heat is variable, and relative as to each other, the term specific caloric has been applied. From these conclusions, we may readily perceive what is implied by an equality of temperature. That it merely depends on the state of rest, which caloric necessarily comes to, and which is relative as respects the capacity of bodies, and nothing more, is a deduction very plain and obvious. Heat, in a state of motion, may be said to be progressing to a quiescent state; and equalization of temperature, although differently understood, may be considered an equalization of fixed caloric, according to the relative capacity of bodies, without regarding the equalization, which takes place of uncombined caloric, as is manifested by thermometrical instruments. In a word, by considering caloric in this view, that of tending to a state of rest, and uniting with bodies according to their respective capacities, we may account for many phenomena; as, for instance, the quantity of caloric which enters into ice, and becomes latent, during liquefaction. The quantity of caloric, in this respect, may be learnt by adding a pound of ice at 32 degrees to a pound of water at 172 degrees. The temperature will be much below 102 degrees, the arithmetical mean, viz. 32 degrees. It is evident that the excess of caloric has disappeared; and by deducting 32 degrees from 172 degrees, 140 degrees remain, which is the quantity of caloric that enters into a pound of ice during liquefaction, or the quantity required to raise a pound of water from 32 degrees to 172 degrees. This change of capacity appears to be absolutely essential to the well being of the universe, as affording a constant modification of the action of heat and cold, the effects of which would otherwise be inordinate. If this did not take place, the whole of a mass of water, which was exposed to a temperature above the boiling point, would be instantly dissipated in vapour with explosion. The polar ice, would all instantly dissolve, whenever the temperature of the circumambient air was above 32 degrees, if it were not that each particle absorbs a quantity of caloric in its solution, and thereby generates a degree of cold which arrests and regulates the progress of the thaw; and the converse of this takes place in congelation, which is in its turn moderated by the heat developed in consequence of the diminution of capacity, which takes place in the water during its transition to a solid state. The reason why boiling water in the open air never reaches a higher temperature than 212 degrees is evident, if we consider, that the capacity of those portions of liquid, which are successively resolved into a vapour, becomes thereby sufficiently augmented to enable them to absorb the superabundant caloric as fast as it is communicated.

The most obvious effect of caloric on bodies, is the change, which they undergo when exposed to its action.

That it acts constantly in opposition to the attraction of cohesion or of aggregation, by which bodies pass from a solid to a fluid, and from a fluid to an aeriform state, and produces also different changes in bodies,—are facts that come under our daily observation.

It occasions changes in the bulk of bodies; hence solids, liquids, and gases are expanded. The expansion, and subsequent contraction of atmospheric air, give rise to various winds, which are currents of air rushing from one point of the compass to another to maintain an equilibrium. The theory of the winds is predicated on this fact, although some have asserted, that they depend greatly on the diurnal motion of the earth. The air thermometer of Sanctorius, and the differential thermometer of Leslie, are founded on this principle, of the expansion of air. Fluids expand until they arrive at the boiling point, as is the case with water, alcohol, &c. The expansion of mercury, in a glass tube, furnished with a graduated scale, forms the mercurial thermometer, by the rise and fall of which, the different variations of temperature are marked.

Notwithstanding caloric has the property of expanding bodies, there are some exceptions to this law, which may be proper to notice. Water, for instance, at the temperature below 40° contracts at every increment of temperature until it reaches 40°, which is its maximum of density. Above 40° it expands, until it arrives at the boiling point. Alumina, or pure argillaceous earth, also contracts by heat; hence it is used in the pyrometer of Wedgwood, to measure by its contraction intense degrees of heat. Various saline substances, in the act of crystallization, also expand. Several of the metals, when previously melted, on cooling exhibit the same character; and water, in the act of freezing, exerts a powerful force by its expansion, competent to the bursting of shells, and the splitting of rocks.

The changes in bodies, produced by caloric, we have already noticed. We will only add, that fluids require different temperatures, called the boiling point, to make them boil, under the same atmospheric pressure. Water boils at 212°. Many observations have been made with respect to water, both in the state of ice, and the state of vapour. Besides the accession of 212 degrees of caloric, appreciable by the thermometer, in water in the state of steam, there is also an accession of non-distributable caloric, called latent heat, which is calculated at 1000°. In consequence of this circumstance, steam has been judiciously applied to various useful purposes, and particularly in a certain manner for the drying of gunpowder.

That chemical changes are produced by the agency of caloric, is a fact well known. It is supposed to occasion decompositions, according to the laws of affinity, by changing previous affinities, and causing new affinities to take place. Hence the operations by fire, whether the substances themselves are exposed in a dry state to the action of heat, or otherwise, produce new results, or compounds, which could not be made without it. This truth has long been obvious. In consequence of a knowledge of this fact, Dr. Black (Lectures vol. i, p. 12,) defined "chemistry to be the study of the effects of heat and mixture, with the view of discovering their general and subordinate laws, and of improving the useful arts."

Caloric as a powerful auxiliary, performing as it does an innumerable multitude of changes and effects, an agent by which the operations of the universe are maintained in order and harmony for universal good, exerts the same effect in the furnace of the chemist, as in the great laboratory of nature; and regulates, and determines all the consequences, which follow a succession of fixed, and appointed changes.[4]

We have thus, in this brief and hasty outline of the nature, principal effects, and properties of caloric, detailed the leading facts on this subject; from which it will be seen, that caloric, so far as respects its generation by the combustion of different pyro-mixtures, and effects, generally, should form a part of Pyrotechny, and claim the attention of those, who are connected with the preparation of Fire-Works.

Respiration is also a process which puts quiescent heat in motion.[5]

In the second part of the work, we embrace the furniture of a laboratory, for the use of fire-workers, consisting of various tools and utensils.

Under this head, we also embrace sundry manipulations, such as the preparation of substances for use, the manner of forming mixtures, and various anterior operations. The formation of pasteboard for cases, the mode of forming as well as charging cases, different modes of charging rockets, the dimensions of rammers, mallets &c. This preliminary ought to be well understood; as the successful practice of the art depends greatly on these operations. We may observe, however, that we have had occasion to repeat some of these manipulations in certain instances, to make them more intelligible; or rather to present, more in connection with the subject, a detail of minutiæ.

In the different compositions, the reader will bear in mind, that the copious collection of formulæ, both old and new, embraces all the facts, with which we are acquainted, concerning pyrotechnical preparations.

In most instances, where the importance of the subject required it, we designated, or set apart from the rest, formulæ, which have been approved, and particularly in France.

This is more particularly the case as it respects the fourth and last part, which appertains exclusively to Military Fire-Works. On this subject, permit me to remark, that fire-works, intended for the purposes of war, should be depended on; and for that reason, in order to produce a certain effect, the materials of which they are composed should be pure, weighed with accuracy in the proportions required, and carefully mixed according to the rules laid down. It is true, however, that while this nicety is required in particular cases, it is unnecessary in the formation of all fire-works. The composition for carcass and light-ball, for tourteaux, links, and fascines, and some others, do not require that precision; whereas the composition for fuses for bombs, howitzes, and grenades should be in every respect accurately made; for on the accuracy of the composition, must depend the time a fuse will burn, which is afterwards regulated by using more or less of the fuse, according to the time it will take for the shell to reach its destination, on which depends the skill of the bombardier. Accuracy, however, in making of preparations should be a general rule.

Viewing Pyrotechny either as a science or an art, there is undoubtedly required in its prosecution much skill and practice. A knowledge of the theory of fire-works may be readily acquired. The mere artificer or fire-worker, by constant habit and experience, may understand it is true how to mix materials, prepare compositions, charge cases, and perform all other mechanical operations; but it is equally certain, that, without a knowledge of chemistry, he cannot understand the theory. We would not say, that the workman should be a chemist, but that he should know enough to determine the purity of the substances he employs, and their respective qualities and effects; for if that principle were admitted, we might go further and say, that every person, who practices a chemical art, as the tanner, gluemaker, brazier, &c. should be a chemist, or that the art could not be conducted without a previous knowledge of chemistry, which we know is contrary to fact. This, however, may be said, that in all arts which are decidedly chemical, as that of dying for instance, chemical knowledge will enable the artist or operator to conduct his processes with better advantage, and correct any old routine, which is too often pursued, because it was handed down from generation to generation. Mr. Seguin in France facilitated the preparation of tanned leather, by adopting a new process altogether chemical. In a word, so far as chemistry is connected with the arts, and by which we explain the operations that take place, it is undoubtedly important; and with regard to Pyrotechny, it appears, in the way we have mentioned, to be indispensable. Chaptal (Elements de Chimie) observes, that the works of artificers frequently miscarry in consequence of their being unacquainted with the art.

In noticing this subject, we may be permitted to digress, while we state, that, being fully convinced of this truth, we have directed our labours in the Chemical Department of the United States' Military Academy to two distinct objects; viz. to theoretical and experimental chemistry, forming the first year's course, and chemistry in its application to the arts, manufactures, and domestic economy, constituting, along with mineralogy, the course of the second year. In addition to the usual applications, Pyrotechny, in the manner we have stated, and especially that branch which treats of military fire-works, has claimed our attention; and we have reason to believe, that this addition, to the usual course of chemical instruction, has considerably advanced the utility, especially to gentlemen designed for the army, of the application of chemistry.

The system of instruction adopted throughout the academy, in the different departments, (the plan of which may be seen in the new Army Regulations, article Military Academy), which, we have no hesitation in believing, is the most complete of any in the United States, and by far the most extensive,[6] is so regulated, that each section of a class regularly recite, and are interrogated on each subject of instruction, so that, while an emulation to excel is thus excited, the comparative merit or standing of the cadets is thereby determined. Adopting the same system in the Chemical department, that of interrogation on the subject of the preceding lecture, has many peculiar advantages; so that, while the mind and memory of the pupil are thus exercised, a comparative estimate of the progress of each one is obtained during each week, by which we are enabled, as in other departments, to present a Weekly Class Report of their progress.

While we are indebted to the talents and industry of the professors and teachers of the Academy, for the flourishing condition it is now in, and the progress of the cadets in every branch there taught; it is but justice to remark, that for the present organization of the academy, as relates to the studies, which is obviously preferable to the old system, and also for the improvements in instruction, we are indebted to the present superintendent, Col. S. Thayer, of the U. S. corps of engineers.

Considering pyrotechny, abstract from the questions usually given, and forming a distinct branch, it may be proper to remark, that the interrogatories on this head have been minutely and satisfactorily answered. The following outline will exhibit the order in which such questions were put, observing, however, that they are merely in connection with this subject:

What is saltpetre? What is nitric acid? What is potash? What are the sources of saltpetre, and how is it obtained? How is it formed in nitre beds, extracted, and refined? What circumstances are necessary to produce nitre, and how does animal matter act in its production? What is the difference between the old and new process for refining saltpetre? What reagents are used to discover the presence of foreign substances in nitre? What are nitre caves? Where do they exist? What are the nitre caves of the Western country, and how is nitre extracted from the earth? What proportion of nitre does the saltpetre earth of the nitre caves afford? What is the theory of the process for extracting saltpetre from nitrous earth, or nitrate of lime? What is sulphur? How is it obtained, and how is it purified for the manufacture of gunpowder? Of what use is sulphur in the composition of gunpowder? Does it add to the effective force of gunpowder? What is charcoal? What is the best mode of carbonizing wood for the purpose of gunpowder? What woods are preferred for this purpose? In the charring of wood, what part is converted into coal, and what gas and acid are disengaged? What is the use of charcoal in gunpowder? What is gunpowder? What are considered the best proportions for forming it, and what constitutes the difference between powder for war, for gunning, and for mining? How does the combustion of gunpowder take place? Can you explain why combustion takes place without the presence of a gaseous supporter of combustion, as gunpowder will inflame in vacuo? What are the products of the combustion of gunpowder? What gases are generated? To what is the force of fired gunpowder owing? What are the experiments of Mr. Robins on the force of gunpowder? How would you separate the component parts of gunpowder, so as to determine their proportions? What are gunpowder proofs? What is understood by the comparative force of gunpowder? What are eprouvettes? &c. In noticing in the same manner the preparations used for fire-works, and for war, as the rocket for instance, the following questions were propounded; viz. What is a rocket? How is it formed? Is the case always made of paper? What is the war rocket? What is the composition for rockets, and how does it act? What particular care is required in charging a rocket? What is the cause of the ascension of rockets? What is the use of the conical cavity, made in a rocket at the time it is charged, or bored out after it is charged? How do cases charged with composition impart motion to wheels, and other pieces of fire-work? What is understood by the rocket principle? What is the rocket stick, and its use? Is the centre of gravity fixed, or is it shifting in the flight of rockets? How are rockets discharged? What is the head of a rocket? What is usually put in the head? Are all rockets furnished with a head? What is understood by the furniture of a rocket? How are the serpents, stars, fire-rain, &c. forming the furniture of a rocket, discharged into the air, when the rocket has terminated its flight, or arrived at its maximum of ascension? What forms the difference between a balloon, in fire-works, and a rocket? As the balloon contains also furniture, and is projected vertically from a mortar, how is fire communicated to it, so as to burst it in the air? Is the fuse used, in this case the same as that for bombs, howitzes, and grenades? What is the Asiatic rocket? The fougette of the French? In what seige were they employed with success by the native troops of India? What was the nature of their war-rocket? What is the murdering rocket of the French? Is the conical head hollow, or solid, blunt or pointed? Why is it called the murdering rocket? What is the Congreve rocket? Is Congreve the inventor, or improver of this rocket? What are Congreve rockets loaded or armed with? In what part is the load placed? Is the case made of paper or sheet iron? What are the sizes of Congreve rockets?

What are the ranges of Congreve rockets? What angle of elevation produces the best range? How are Congreve rockets discharged in the field, and what number of men are usually employed for that service? Are the Congreve rockets considered to be a powerful offensive weapon; and, if so, in what particular? What is a carcass rocket? As an incendiary, is the carcass rocket equal to the usual carcass thrown from mortars? What is the carcass composition made of? What is the Congreve rocket light ball? In large rockets, are their sticks solid, or bored and filled with gunpowder? Why is that expedient used? &c.

It is obvious, that the student, after obtaining a knowledge of each subject by the preceding lecture, accompanied with demonstrations, is enabled to detail minutely all the facts in relation to it.

Pyrotechny, as known at present, is confined to a few books, and scattered in a desultory manner, without any regular or connected system. In fact the works which treat on this subject are in French, or translations from the French on particular subjects, but generally very imperfect. As applied to the uses of war, we may indeed say, that the small treatise of Bigot, (Traité d'Artifice de Guerre), and Ruggeri (Pyrotechnie Militaire) are the only works. We have, therefore, consulted these authors, as will be seen in the pages of the work.

Roger Bacon, in his Opus Majus, has given some account of the Greek fire, and of a composition, which seems to have had the effect of our modern gunpowder.

Malthus (Traité de l'Artillerie) contains some formulæ for Military Fire-Works. Anzelet and Vanorchis, in their several works, have given some receipts for incendiary preparations. Henzion (Recreations Mathématiques) and Joachim Butelius have also something on the subject.

The celebrated Polander, Casimir Siemienowicz, has nothing of any moment, if we except the incendiary fire-rain, an account of which may be seen in the fourth part of our work. His book is considered, however, the best of the whole of them. Belidor, Theodore Duturbrie, &c. have mentioned some preparations; but their works are chiefly confined to artillery.

The improvement of Pyrotechny is ascribed to the Germans and Italians, and the French acknowledge, that they are indebted for a knowledge of it to the Italians. Be this as it may, it is certain, that it was known in China from time immemorial. Their acquaintance with gunpowder, before it was known in Europe, is a fact which appears to be generally admitted. For an account of the Chinese fire-works, and the origin of gunpowder in Europe, consult these articles respectively.

Whatever merit we may claim in this work, as the public will be able to judge impartially, it will be seen, by referring to the different chapters and sections, that we have endeavoured to form a system, by presenting a connected view of the whole subject.

Having noticed under separate heads, the particular use and application of each composition, we have added a chapter on the arrangement of fire-works for exhibition, together with the order to be observed. We may remark here, that we have enlarged in this part more perhaps than its merit or importance deserves; but, on reflection, we thought it better to embrace the whole subject, in order to form a more complete system in all its parts.

After going through the fire-works for exhibition, and noticing the different formulæ, and preparations, for arrangement, with the theory of effects, we consider, in the next place, a subject of more importance, that of Military Pyrotechny. We have adopted this arrangement, more on account of obtaining a better acquaintance with ordinary fire-works, before the reader is prepared for military works, which he will understand with more facility; for all the preliminary operations precede the practical part.

On this head, it will be sufficient to add, to what we have already stated, that we have given in each article, generally speaking, a variety of formulæ, with ample instructions for the preparation of each composition. The table of contents will exhibit the order in which they are treated.

In noticing the substances used in fire-works, in the first part, it will be perceived, that we have noticed some of them more extensively according to their importance; as for instance, saltpetre. Besides the different modes of obtaining saltpetre in Europe and elsewhere, and the means employed for refining it, we mention the saltpetre caves of the western country, which furnish an abundance of this article, and which contain an almost inexhaustible supply.

The extraction of saltpetre from the earth, (principally nitrate of lime), by using a lixivium of wood-ashes; the formation of rough, and subsequently of refined nitre; the various methods of refining saltpetre, and particularly that adopted in France; with sundry facts respecting the origin of nitre, and on the formation of artificial nitre beds; all claim our particular notice.

The extraction of sulphur from its combinations, and the means used for purifying it for the purpose of gunpowder, are also considered in the same manner.

The subject of charcoal, an essential constituent of gunpowder, claims, in like manner, particular attention. The various modes of charring, the woods employed, the quantity of coal obtained, the formation of pyroacetic acid in the process of carbonization, and many facts of the same kind are considered. These subjects, viz. nitre, charcoal, and sulphur, are highly important to the manufacturer of gunpowder.

A knowledge of the various processes for refining saltpetre; the best and most approved modes of carbonizing wood; the purification and quality of sulphur; the different processes for making gunpowder, with the proportion of the ingredients used in France and elsewhere; the granulation, glazing, and drying of powder, the use of the steam apparatus, and the different modes of proving it, and of examining it chemically; and the means of ascertaining the purity of nitre in any specimen of gunpowder; are, with others, subjects of particular interest to the gunpowder manufacturer.

With respect to the Theory of the explosion of gunpowder, we have noticed it at some length, and have added the experiments and observations of Mr. Robins, and of other persons, made at different periods.

In the consideration of the gaseous products, and the caloric evolved by the combustion of powder, we have taken a view of the gases produced, the cause of their production, the dilatation which they suffer, and the experiments of Lavoisier and Laplace, with regard to latent heat, and deducing therefrom some views of the probable cause of the production of caloric in fired gunpowder.[7]

Our observations respecting rockets, the theory of their ascension, of the Congreve carcass and Asiatic rockets, and some others, are we apprehend sufficiently extensive. As it regards the different incendiary compositions, and their use in war, the reader will find ample instructions on these heads.

We may also remark, that we have given some of the more common, or general properties of the substances, employed in the composition of fire-works, without going into that detail, which belongs exclusively to works that treat of Chemistry. It was neither our design, nor have we given, for the reasons thus stated, all the chemical characters or properties of the substances so employed; and, therefore, have confined ourselves, generally speaking, to an enumeration of such properties as are connected with the subject, or are indispensably necessary to be known, before a rationale of the causes and effects can be understood.

It was our intention to accompany the work with plates, exhibiting the arrangement, &c. of fire-works, which, there can be no doubt, would have facilitated in particular the knowledge of forming, and arranging, certain pieces of fire-work; but, on second reflection, as such illustrations were connected more with fancy exhibitions, and have little or no relation to Military Fire-works, the most useful branch of Pyrotechny, we were finally of opinion, that the addition of plates would greatly enhance the price, without advancing or adding to the value of the work.

If, however, a second edition should be required, various figures in illustration of particular subjects may be added, either with a distinct explanatory chapter, or a reference from the articles themselves, with the necessary explanation, to the figures respectively.

It would require at least twenty-five plates to include all the figures we originally intended to have introduced.

Before concluding this introduction, it remains for us to remark, that, in forming this work, we consulted a variety of authors, but with little advantage, except some French works, which we shall notice. Chaptal (Chimie Appliqué aux Arts;) Bigot (Artifice de Guerre;) Morel (Feux d'Artifice;) Thenard (Traité de Chimie;) Ruggeri (Pyrotechnie Militaire;) MM. Bottée and Riffault (Traité de L'Art de Fabriqué la Poudre à canon;) Peyre (Le Mouvement Igné;) Biot (Traité de Physique, Recherches Experimentales et Mathématique, sur les mouvement des Molecules de la Lumiere, &c.;) M. Duloc (Theorie Nouvelle sur le Mechanisme de l'Artillerie;) the Dictionnaire de l'Industrie; the Dictionnaire Encyclopedique des Arts et Metiers Mecaniques, article Art de L'Artificier; Œuvre Militaire; Archives des Découvertes; Système des Connoissances Chimiques par A. F. Fourcroy; Aide-Mémoire a l'usage des officiers d'Artillerie de France.

We examined various authors in English; and with regard to the origin of inventions, we found the learned, and valuable work of professor Beckman (History of Inventions) very useful, and likewise James's Military Dictionary. To the Encyclopedia Britannica, we are indebted for many interesting facts, and some extracts on fire-works for exhibition.

On the subject of mining, we consulted the Treatise on mines for the use of the Royal Military Academy, by Landmann.

We deem it necessary to observe, that, in collecting our formulæ for military fire-works, although we have sometimes extracted from the Strasbourg Memoir, the Bombardier and Pocket Gunner, and the Military Dictionary of Duane and James, we have generally followed Bigot; as the formulæ which he gives for the preparation of Military fire-works have been approved by the French government; and where any thing of importance occurred in Ruggeri, we have, for the same reason, extracted such formulæ from that author.

As respects the turtle, torpedo, and catamarin, submarine machines, it appears that Bushnel (Trans. Am. Phil. Soc.) claims the originality of the discovery from the date of his invention, although similar contrivances had long ago been suggested. Fulton's improvements, in the torpedo, are deserving of particular attention; but it is plain, that the Catamarin of the English is the same in principle and application as Fulton's torpedo, and that Fulton deserves the merit of it. Congreve, if we believe Ruggeri, was not the inventor of the rocket, which bears his name; for, according to him, it was invented about the year 1798 by a naval officer at Bourdeaux. It is certain, however, it was neither much known, nor used before the attack on Copenhagen.

It is certain that the present incendiary fire-stone was taken from the recipe for fire-rain contained in the military work of Cassimir Siemienowicz, or that the fire-rain gave rise to a similar preparation. The idea of the pyrophore, mentioned in the Archives des Découvertes, must have originated from the use of the powder-barrel, and of similar means of defence. We might enumerate many other inventions, which owe their origin in the same way.

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.

In the composition of artificial fire, various substances are employed, having different properties, and designed to produce certain effects characterised by particular phenomena. These substances are either inflammable, or support the combustion of inflammable bodies. As pyrotechnical mixtures are differently formed, and of various substances, the effects are also modified, although combustion, under some shape always takes place.

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.

That the magicians were conscious of their inability to work miracles, is evident from their own declaration; for, after vermin had been brought forth by Moses and Aaron, they endeavoured to do the same, and being unsuccessful declared, that this was the finger of God; and many other instances are recorded of their attempts being altogether abortive. It appears also, that at first they believed they were able to perform all that Moses had done; and Pharaoh himself, by calling them together for that purpose, seemed to be of the same opinion, until he and his servants were finally convinced that Moses and Aaron wrought such miracles by inspiration. There can be no relation whatever between Moses and the magicians; for although he was, if we may judge from biblical history, acquainted with all the knowledge of the magicians, his mission was altogether of a different character. Many of the modern Greek and Armenian priests, in their celebration of the holy fire, palm upon their credulous followers, a belief, that they possess the power of working miracles, as will appear from the account we shall give of them. We will not enlarge on this subject at present, but pass on to consider the more common performances, which have excited the wonder and admiration of mankind.

The deception of breathing out flames, which excites the astonishment of the ignorant, is very ancient. When the slaves of Sicily, about two centuries ago, made a formidable insurrection, and avenged themselves in a cruel manner for the severities which they had suffered, there was among them a Syrian named Eunus, a man of great craft and courage, who, having passed through many scenes of life, had become acquainted with a variety of arts. He pretended to have immediate communication with the gods; was the oracle and leader of his fellow slaves; and, as is usual on such occasions, confirmed his divine mission by miracles. When, heated by enthusiasm, he was desirous of inspiring his followers with courage, he breathed flames or sparks among them from his mouth while he was addressing them. We are told by historians, that, for this purpose, he pierced a nut shell at both ends, and, having filled it with some burning substance, put it into his mouth and breathed through it. Some affirm, that he used tow previously soaked in a solution of saltpetre. The deception at present is much better performed. The juggler rolls together some flax or hemp; sets it on fire; and suffers it to burn till it is nearly consumed; he then rolls round it, while burning, some more flax, and by these means the fire may be retained in it a long time. When he wishes to exhibit, he slips the ball into his mouth and breathes through it; which again revives the fire, so that a number of weak sparks proceed from it; and the performer sustains no hurt, provided he inspire the air not through the mouth but the nostrils.

By this art, the rabbi Bar-Cacheba, in the reign of the emperor Hadrian, made the credulous Jews believe, that he was the hoped for Messias, and two centuries after, the emperor Constantius was thrown into great terror, when Valentian informed him, that he had seen one of the body guards breathing out fire and flames in the evening.

It appears evident from the writings of Herodotus, that the ancients possessed a knowledge of attracting lightning, or the electric fluids with pointed instruments made of iron. He informs us, that the Thracians disarmed heaven of its thunder-bolts, by discharging arrows into the air; and the Hyperboreans by darting into the clouds, pikes headed with pieces of sharp pointed iron.

Pliny speaks of a process, by which Porsena caused fire from the heavens to fall upon a monster which ravaged his country. He mentions also, that Numa Pompilius, and Tullius Hostilius practised certain mysterious rites to call down the fire from heaven. What these mysterious rites were is of no moment; the fact is sufficient. Tullius, because he omitted some prescribed ceremony, is said to have been killed by the fire. A similar accident happened in France with the electrical kite.[10]

For deceptions with fire, the ancients employed a number of inflammable substances, which they dexterously used; among them, naphtha, a fine bituminous oil, which readily inflames, was principally used. (For the effect of naphtha, see Greek fire.) Galen informs us, that a person excited great surprise by extinguishing a candle, and again lighting it without any other process than holding it against a wall or a stone. This, Galen observes, (De Temperamentis, iii. 2, p. 44.) was effected in consequence of the wall or stone being previously rubbed with sulphur, which, however, must have been something more. He also speaks of a mixture of sulphur and naphtha. If it had been phosphorus, or some of its preparations, it would appear more probable.

Plutarch relates the secret effects of naphtha, and observes, that Alexander was astonished and delighted, when it was exhibited to him in Ecbatana. Medea destroyed Creusa, the daughter of Creon, with this oil. This fact is stated by Plutarch, Pliny, Galen, and others, and believed by Beckman. She sent, it appears, to the unfortunate princess, a dress covered with it, which burst into flames as soon as she approached the fire of the altar. The dress of Hercules, which also took fire, was dipped in naphtha, though said to be in the blood of Nessus. On the subject of naphtha, Beckman remarks, "that this oil must have been employed when offerings caught fire in an imperceptible manner. In all periods of the world, priests have acted as jugglers to simple and ignorant people."

The most ludicrous account of the necromantic art, by which similar tricks were performed, is that given by Celini, (Life of Benvenuto Celini, a Florentine Artist, by T. Nugent, LL. D. &c.) of a Sicilian priest, who drew circles on the floor with various ceremonies, using fire and different perfumes. Having made an opening to the circle, and thrown perfumes into the fire at a proper time, he observes, that in the space of an hour and half, "there appeared several legions of devils, insomuch that the amphitheatre was quite filled with them." Benvenuto, it seems, at the instance of the priest, asked some favours of them, which, however, he never realized. At a second exhibition he held a pentagorun, while the priests questioned the leaders of the demons "by the virtue and power of the eternal uncreated God," using the Hebrew, Greek, and Latin languages. The Demons appeared more numerous than at first, and more formidable. He states that "quivering like an aspen leaf, he took good care of the perfumes," and was directed by the priest "to burn proper perfumes." This ceremony was continued until the "bell rang for morning prayers," and the priest "stripped off his gown and took up a wallet-full of books," declaring, "that as often as he had entered magic circles, nothing so extraordinary had ever happened to him!" How is it, in the language of professor Beckman, that "in all periods of the world, priests have acted as jugglers to simple and ignorant people?" * * * * *

This same Benvenuto Celini, however, was a man of intelligence. He wrote a work called the History of Jewelry; in which the first idea of phosphorescent mineral bodies is to be found. This work was written in the beginning of the 16th century. His life, although singularly marked, what with popes, priests, artists, and necromancers, presents a singular retrospect.

What was more absurd, and even profane, than the tricks of Joseph Balsamo, called Il Conte Cagliostro, who with Schœpfer, revived the study of the magical arts; and who with invocations, friction, fumigations, and optical deceptions astonished the ignorant of their day. Whether like Æneas, in his descent to hell, they made their way with their falchions through crowds of ghosts, or like Dioscorides, relied on the efficacy of herbs, or like Paracelsus, carried an evil spirit in their canes, or wore a jewel like Shakspeare's toad, which possessed marvellous virtues, or employed the magic stone (agate) of the east, and invoked their urim and thummim,—it is certain they worked upon the imagination of the people. By the application of conium maculatum, (hemlock) consisted the ceremony of ordaining a Hierophant; by the hartshorn of Orpheus, they had a divine remedy for the passions of the body; and by a mixture of new mustard and olive oil, they could produce a symphony, which invoked the spirits, and, Pythonesis like, declare to the people, that they "had devils in their bellies!!"

Of the phial of Cagliostro, Cardan relates that he had this phial twice exhibited to him, and complains bitterly of having seen nothing, after the anthem Sancte Michael, but some bubbles that issued from the bottom, though it was believed that these bubbles were angels! He says, "Nihil tamen omnino vidi poste hanc invocationem nisi bulas pauculas quasdam ex imo gutti fundo exæstuantes." Aulus Gellius and Hero mention tricks of this kind practised by the Egyptians. Roger Bacon, the alchymist, was excommunicated by the pope, and imprisoned ten years, for supposed dealings with the devil.

Equally absurd to a man of reflection, are the observations of antiquated writers on spontaneous generation, by heat. Borello (Physical History) tells us, "that fresh water craw fish may be regenerated, by their own powder, calcined in a crucible, then boiled in water with a little sand, and left to cool, for a few days; when the animalcula will appear swimming merrily in the liquor, and must be then nourished with beef blood, till they attain the proper size to stock your ponds with."[11] The Sieur Pogeris and M. de Chamberlan, both agree with Signior Borello, but, in the chemistry of the matter, they add that the operation must be performed, during the full of the moon! If this lunar system be adopted, would not the crab also, have been a more favourable sign to have ruled the nativity of craw fish?

Swift, however, alludes to these agencies, fallacious as they are, in the following lines:

"So chymists boast they have a power,

"From the dead ashes of a flower,

"Some faint resemblance to produce,

"But not the virtue, taste, or juice."

Rochos, equally absurd with Borello, says, in The Art of Nature, that the ashes of toads will produce the very same effect, as the powder of crabs' eyes! Reasoning upon that ridiculous and unnatural principle of Cæsalpinus, in his comment on Aristotle, Quæcumque ex semine fiunt, eadem fieri posse sine semine, the procreation of eels from rye-meal, or mutton broth was predicated.

Julius Camillus, however, would out-do nature herself; for Amatus Lusitanus affirms, that he has seen his phials full of homunculi complete in all their parts! Paracelsus (De Rerum Natura,) had the same and many other absurd notions. What, we may truly say, has not been palmed upon the world, when we are told, that the following translation from a Hague Gazette, which appeared in the British Evening Post, No. 1645, contained facts, which were confidently believed by the ignorant:

"Mr. Tunestrick, by origin an Englishman, has just exhibited at Versailles, a very singular experiment. He opened the head of a sheep, and a horse from side to side, by driving a large iron wedge into the skull, by means of a mallet; drew the wedge out afterwards, with pincers, and recalled the animals to life, by injecting through their exterior aperture with a tin syringe, a spirituous liquor of his own composition, to which he attributes surprising effects! The taste of this liquor resembles that of Commandus Balm!!" The remarkable effects of galvanism, however, are well authenticated; but resuscitation, notwithstanding all apparent life, has in no instance, to our knowledge, been effected. (See Ure's Chemical Dictionary, article Galvanism.)

Among other tricks, we may mention those with serpents, especially in the East Indies, and neighbouring islands, where a certain class of people exhibit them for money.[12]

Persons who could walk over red-hot coals, or red-hot iron, or who could hold them in their hands and their teeth, are frequently mentioned. In the end of the 17th century, Richardson, an Englishman, was a great adept in this performance. We are assured he could chew burning coals, pour melted lead upon his tongue, swallow melted glass, &c; but the fact is incredible.

It is true, that the skin may be prepared in such a way as to become callous and insensible against the impression made on the feet and hands. It may be rendered as firm as shoes and gloves. Such callosity may be produced, if the skin is continually compressed, singed, pricked, or injured in any other manner. Beckman relates, that in 1765, he visited the copper-works at Awestad, when one of the workmen, for some money, took some of the melted copper in his hand, and after showing it, threw it against a wall. He performed a variety of other experiments with the melted metal.

The workmen at the Swedish melting-house have exhibited the same thing to some travellers in the 17th century. The skin is first rendered callous by frequently moistening it, as Beckman says, with sulphuric acid; and also, he remarks, by using the juice of certain plants. The skin must also be rubbed frequently, and for a long time, with oil. Haller, in his Elementa Physiologica, V. p. 16, speaks of this fact.

The manner of rendering the hands callous, or insensible, so that they may take up, and hold, ignited iron, charcoal, or other substances, may be seen in an English publication of 1667. The Journal des Savants, of 1677, contains the secret. "It consists in applying to the hands, various pastes, with spirits of sulphur, (sulphuric acid,) which destroys the epidermis, &c. and the nervous energy." This corroborates the account by Beckman. We read that Richardson had prepared his tongue in such a manner, that he could hold on the point of it a live coal, covering it first with pitch, rosin, and sulphur, and could hold a piece of ignited iron between his teeth. After showing the coal on his tongue, he would then extinguish it in his mouth. The Mémoires de l'Académie state, that a person who is salivated can put a live coal in his mouth. The Dictionnaire de l'Industrie observes, that the sulphur diminishes the heat of the coal, for the flame is less hot than a candle; and that the flame of a combination of pitch, rosin, and sulphur, is still less hot, and by no means so considerable as we would imagine. In the experiment, the rosin is not melted, and the flame of the sulphur is inconsiderable. M. Gallois observes, that he witnessed in the Swedish iron founderies, the men hold melted cast iron in their hands, doubtless having them previously prepared.

The traces of this art may be found in the works of the ancients. A festival was held annually, on Mount Soracta, in Etruria, at which the Hirpi, who lived not far from Rome, jumped through burning coals, and on this account had certain privileges granted them by the Roman Senate.

Women also, we are informed, were accustomed to walk over burning coals, at Cartabola, in Cappadocia, near the temple dedicated to Diana. Servius remarks, that the Hirpi did not trust to their sanctity so much as they did to the preparation of their feet for the operation!

With respect to the ordeal by fire, which it seems was performed in several ways, one was, that when persons were accused, they were obliged to prove their innocence by holding in their hands red-hot iron. This mode of exculpation, as it is called, was allowed only to weak persons, who were unfit to wield arms, and particularly to monks and ecclesiastics, to whom, for the sake of their security, the trial by single combat was forbidden. In Grupius' learned dissertation, in the German, p. 679, as quoted by Beckman, we read, that the trial itself took place in the church, under the inspection of the clergy; mass was celebrated at the same time; the defendant and the iron, were consecrated, by being sprinkled with holy water; the clergy made the iron hot themselves; and they used all these preparations, as jugglers do many motions, only to divert the attention of the spectators. It was necessary that the accused person should remain at least three days and three nights, under their immediate care, and continue as long after. They covered their hands both before and after the proof; sealed and unsealed the covering: the former, as they pretended, to prevent the hands from being prepared by art; and the latter to see if they were burnt.

Some artificial preparation was undoubtedly necessary, or why prescribe three days for the defendant, who, if they wished to make him appear innocent, had a certain preventive against the actual cautery? The three days allotted, after the trial, were requisite, in order to restore the hands to their natural state. The sacred sealing secured them from the examination of presumptuous unbelievers.

When the ordeal was abolished, it no longer was kept secret. In the 13th century, an account of it was published by a Dominican Monk, Albertus Magnus. In the work of this author, entitled, De Mirabilibus Mundi, he has given the receipt for the composition. It seems that it consisted in covering the hands with a kind of paste, and not by searing them. The sap of the althæa, or marsh mallow, the mucilaginous seeds of the fleabane, together with the white of an egg, were mixed, and by applying this mixture, the hands were as safe as if they had been secured by gloves. The use of this mixture, for the same purpose, may be traced back, it is said, to a pagan origin. In the Antigone of Sophocles, the guards, placed over the body of Polynicus, which had been carried away and buried, contrary to the orders of Creon, offered, in order to prove their innocence, to submit to any trial: "We will," said they, "take up red-hot iron in our hands, or walk through fire."

The ordeal, by heated ploughshares, was common in England. It seems, according to English History, that queen Emma had charges preferred against her, by Robert, archbishop of Canterbury, for consenting to the death of her son Alfred, and preparing poison for her son Edward, the Confessor. She claimed, by the law of the land, the ordeal, or trial, by burning ploughshares. She passed the nine ploughshares unhurt, which established her innocence, and caused the archbishop to fly the kingdom. The chief trials, by ordeal, appear to have been by fire, water, walking blindfold among heated ploughshares, and swallowing consecrated bread, which last was introduced about the time of pope Eugene. The custom was borrowed from the Mosaic law. An example of its practice occurs in the New Testament, in the story of Ananias and Sapphira; and the remembrance of it, as Blackstone remarks, still subsists among common people, as "May this morsel be my last;" "May I be choked if it is so," and the like; for it appears, that this ordeal was a piece of bread of about an ounce in weight, blessed by the priest, and given to the accused person, who was to try and swallow it, praying that it might choke him if he were guilty. The bible-ordeal, and the drowning-ordeal, are familiar to every one, degrading as they all must have been to human reason, and enlightened principles. Fox, in his Book of Martyrs, speaks of various ordeals, as well as the cruel deaths, and inhuman punishments inflicted, by the hand of bigotry, and fanaticism, under the cloak of religion, which were nothing more than a base and impious prostitution of its genuine principles.

Even among the modern Greeks, the same superstitious notions prevail. Almost every cavern about Athens has its particular virtues, and is celebrated for various things; and the offerings, made by Grecian women, to the destinies, in order to make them propitious to their conjugal speculations, are equally absurd. These offerings, by which they are to work a miracle, consist of a cup of honey and white almonds, a cake on a little napkin, and a vase of aromatic herbs, burning and exhaling an agreeable perfume. We are told, however, that those evil spirits, whose assistance is invoked, for vengeance and blood, are not regaled upon cakes and honey, but on a piece of a priest's cap, or a rag from his garment, which are considered as the most favourable ingredients for the perpetration of malice and revenge. When a person is hated, another absurd custom is used, which is supposed to be followed by dreadful results. It consists in placing before his door, a log of wood, burnt at one end, with some hairs twisted round it. "This curse," says Mr. Dodwell, in his Classical Tour, "was placed with due solemnity, at the door of the English agent, Speridion Logotheti, while I was at Athens; but he rendered it of no avail, by summoning a great number of priests, who easily destroyed the spell, by benediction, frankincense, and holy water!" This story is much in character with that of the exorcism of rats, caterpillars, flies, and other insects, an old ritual of the papal church, performed between the feasts of Easter and the Ascension. A priest who resided at Bononia, performed the ceremony. "I went," he says, "to exorcise the insects in that country, accompanied by a curate, who was a droll fellow, and laughed at the credulity of the people, while he pocketed their money." It appears, however, that in all superstitious ceremonies, fire, under some form, was a pre-requisite; but ecclesiastical fire-works we leave within the pales of the priesthood.

The author of the Dictionnaire de l'Industrie, vol. iii, speaks of a trick, performed with a loaded musket and ball, which, although apparently inconsistent, is nevertheless true, if we consider the action of gunpowder equal. This trick is stated to be the firing of a musket, loaded with ball, at a person, without wounding, or in any way injuring him.

By taking a ball of solid lead of a smaller size than the calibre of the musket, and placing it on the charge in a gun, and as much or nearly so of powder, over the ball, the effect we are assured is, that when the gun is fired, the ball will pass out without any very sensible force, and even drop a few yards from the gun, although the report will be as great as if the charge and ball had been used in the usual manner. This trick is often performed by jugglers, to the great astonishment of the spectators. The mode of catching a cannon ball is also of the same character.

The proper charge of powder for the cannon, is divided into two unequal portions, the lesser of which is placed in the gun as a charge; the ball is placed on it in the usual way, and the rest of the powder (by much the greater portion,) placed over the ball, the lesser quantity being not more than a twelfth part of the whole. A cannon, so charged, will not project the ball more than 20 yards, where it might be caught with safety.

Any person who has been in the custom of shooting, must have frequently observed, that when the shot happens to be mixed with the powder, its range is impeded; and, under similar circumstances, they have even been found only a few yards from the muzzle of the piece. This fact I have witnessed, although I confess I never once reflected on it.

As to the explanation of this phenomenon, it appears, that it can only be accounted for by referring to the action of two opposite forces, mutually repelling each other, added to that of the charge under the ball; hence, the reaction would be equal, if, under the same circumstances, both charges were alike situated: but the effect of the first charge is so much weakened by the counter effect of the second, that the projectile force of the ball becomes comparatively nothing.

There is another trick very often performed, which, however chemical, is not looked upon in that light, neither do performers attempt to explain it; we mean the exhibition of the Glace Inflammable of the French.

The preparation is made in the following manner: melt some spermaceti over a fire, and add a sufficient quantity of spirit of turpentine, and blend them together. The mixture when cold, will become solid, having somewhat the appearance of ice. If made in hot weather, the vessel containing the melted substances must be immersed in cold water. It does not, we are told, remain in a solid state any length of time.

It floats more or less in the fluid, which of course is the spirit of turpentine. The trick, with this preparation, after having put some of the solid and fluid substance together on a plate, is to pour upon it concentrated nitric acid, or a mixture of eight or ten parts of nitric acid, and two of sulphuric acid; inflammation ensues. It is no other in fact than accension of the oil of turpentine; the addition of the spermaceti is altogether secondary, and its effect, if any, must retard instead of promoting the combustion of the turpentine. The art of making this preparation is in rendering the essential oil solid and transparent, without altering its inflammable properties.

There is another trick performed, by burning a thread, to which an ear-ring is tied, and which, notwithstanding the thread is reduced to a cinder, still holds the ring. This is what the French call the Bague suspendue aux cendres d'un fil. The string is first prepared by soaking it for 24 hours, in a solution of common salt, and drying it; then tying it to a ring, and setting it on fire, avoiding any vibration or oscillation of the string. It is obvious that the salt serves to render the cinder cohesive.

We have an account in Maundrel's Travels from Aleppo to Jerusalem, of the office of the Holy Fire. The ceremony is kept up by the Greeks and Armenians, from a persuasion that every Easter eve, a miraculous flame descends from heaven into the holy sepulchre, and lights all the lamps and candles, as the sacrifice was consumed at the prayers of Elijah.

"On our approaching the holy sepulchre," says Maundrel, "we found it crowded with a numerous and distracted mob, who made a hideous clamour; but with some difficulty pressing through the crowd, we got up in the gallery next to the Latin convent, where we could have a view of all that passed. The people began, by running with all their might, round the holy sepulchre, crying out 'huia,' which signifies, 'This is he,' or, 'This is it.' After this, they began to perform many antic tricks: sometimes they dragged one another along the floor round the sepulchre; sometimes marched round with a man upright upon another's shoulders; at others, took men with their heels upwards, and hurried them about with such indecency, as to expose their nudities; and sometimes they tumbled round the sepulchre like tumblers on a stage. In a word, nothing can be imagined more rude and extravagant than what was acted upon this occasion.

"This frantic humour continued from twelve till four, and then the Greeks first set out in a procession round the sepulchre, followed by the Armenians, and marched three times round it with their standards, streamers, crucifixes, and embroidered habits; and towards the end of the procession, a pidgeon came fluttering into the cupola over the sepulchre, at which the people redoubled their shouts and clamours, when the Latins told the English gentlemen, that this bird was let fly by the Greeks, to deceive the people with a belief that it was a visible descent of the Holy Ghost. The procession being over, the suffragan of the Greek patriarch, and the principal Armenian bishop, approached the door of the sepulchre, cut the string with which it was fastened, and breaking the seal, entered, shutting the door after them, all the candles and lamps within having been before extinguished in the presence of the Turks. As the accomplishment of the miracle drew near, the exclamations were redoubled, and the people pressed with such violence towards the door, that the Turks could not keep them off with the severest blows. This pressing forward was occasioned by the desire to light their candles at the holy flame as soon as it was brought out of the sepulchre. The two miracle-mongers had not been above a minute in the sepulchre, when the glimmering of the holy fire was seen through some chinks in the door, which made the mob as mad as any in bedlam; then presently came out the priests, with blazing torches in their hands, which they held up at the door of the sepulchre, while the people thronged with extraordinary zeal to obtain a part of the first and purest flame, though the Turks laid on with their clubs without mercy. Those who got the fire immediately applied it to their beards, faces, and bosoms, pretending that it would not burn like an earthly flame; but none of them would endure the experiment long enough to make good that pretension. However, so many tapers were presently lighted, that the whole church seemed in a blaze, and this illumination concluded the ceremony."

Maundrel afterwards observes, that the Latins take great pains to expose this ceremony as a shameful imposition, and a scandal to the Christian Religion: but the Greeks and Armenians, lay such stress upon it, that they make the pilgrimages chiefly on this account; and their priests have acted the cheat so long, that they are forced now to stand to it, for fear of endangering the apostacy of the people. They entertain many absurd ideas respecting the miraculous power of the holy fire. Even the melted wax of the candle, which had been lighted by it, is covered over with linen, and designed for winding-sheets; "for they imagine," says Maundrel, "that if they are buried in a shroud, smutted with this celestial fire, it will secure them from the flames of hell!"

Before concluding this article, we shall mention a subject highly interesting in optics, which, in some of its forms, was employed by the old magicians; we mean the phantasmagoria. The exhibitions of this kind, when first got up, drew the attention of Europeans, and particularly the French, who greatly improved the apparatus and machinery, and varied the forms and appearances. The principles of the phantasmagoria are described in every work on Natural Philosophy, which treats of optics. The Dictionnaire de l'Industrie, Encyclopedie Méthodique, Biot's Traité de Physique, in French and in English, the different treatises on philosophy and optics, particularly Dr. Smith's, the Cyclopedias, &c. contain either a description, or the principles of it. The third volume of Biot, especially, is full on the subject of optics. With regard, however, to the narrative and explanation of the appearance of the phantoms, and other figures, a subject which immediately concerns us, the account given by Mr. Nicholson, (Journal of Natural Philosophy, Chymistry, and the Arts, vol. i, p. 147.) is the most interesting. Connected with this optical illusion, is the imitation of lightning and thunder, which, from the account, appears also to have been performed.

The phantasmagoria may be considered nothing more than an application of the magic lantern, the invention of which is attributed to Roger Bacon, who was a contemporary with Vitellio, a native of Poland, who published a treatise on optics, in 1270. John Babtista Porta, of Naples, who discovered the camera obscura, having formed a society of ingenious persons at Naples, which he called the Academy of Secrets, wrote the Magia Naturalis, containing his account of this instrument, and, it is said, the first hint of the magic lantern. Kircher, it is known, received his first information of the magic lantern from this book, and afterwards improved it.

Adams (Lectures on Natural and Experimental Philosophy, vol. ii, p. 232. Appendix by the English editor) very justly observes, that persons, unacquainted with the principles of optics, have been surprised at the great illusion of their sight, by an artificial construction of many optical instruments, exhibited by showmen and others: such, for instance, as the optical and dioptrical paradox; the endless gallery; the animated balls by simple reflection; phantoms; causing the appearance of a flower from its ashes; the optical perspective box, and the cylindrical mirror: to which we may add, the enchanted bottle; the enchanted palace; the magic lantern; the magician's mirror; the perspective mirror; the camera obscura; distorting and oracular mirror; the diagonal opera glass, &c. &c.; all which may be seen in Smith's School of Arts.

We may also remark, that optical exhibitions sometimes accompany those of fire, when performed on a small scale. In the phantasmagoria, for instance, whether before, or at the time the exhibition commences, as well as after, thunder and lightning, if well imitated, produces a good effect.

The mechanism of the phantasmagoria is concealed from the spectators, who have only before their eyes a screen of gauze or gummed muslin posited vertically, which serves as the ground of a picture, where the images are depicted by reason of the transparency. The apartment is deprived of all light, except that which proceeds from an apparatus hid behind the screen. At the moment when the operation commences, a spectre appears (as a skeleton, the head of a celebrated person, &c.), at first extremely small, but which afterwards increases rapidly, and thus seems to advance at a great rate towards the spectators. And when the scene passes before them in a room representing a cave hung with black, a solemn silence being occasionally interrupted by mournful sounds from an appropriate musical instrument, it is not easy for an observer to defend himself from the impression of terror, at the sight of an object, in itself formed to produce the illusion, and which finds in the imagination a place already prepared for the reception of phantoms.

The instrument placed behind the gauze screen is in fact a peculiar construction of the magic lantern: only in the former, it is necessary that the lenses should run over a much greater space, and that the instrument may be susceptible of approaching to, and receding from, the frame of gauze, in such manner, that each luminous pencil may be depicted there in a single point. The general construction is this: In a square box, a lamp is placed, the luminous rays proceeding from which, are reflected by a conical mirror, towards an orifice made in the box. At this orifice is placed a tube, blackened within, and composed of several tubes which slide one into another, like those of a pocket telescope. This tube is furnished with two bi-convex lenses of about five inches diameter; one of these is fixed, the other is at the outer extremity of the tube, and is separated from the former in proportion as the tube is lengthened by the aid of a hooked lever situated along the tube, between the lamp and the lenses. A groove is properly adapted to the tube, destined to receive transparent figures; lastly, the box rests upon a table moveable on four wheels, that slide in two channels perpendicularly to the frame on which the images are depicted. It is manifest, that we may augment or diminish the dimensions of the images, and consequently make the spectre appear more or less near to the spectator, by separating farther, or by bringing nearer together, the two lenses; but then the focus of the diverging rays, which proceed from the same point of the transparent body, will be no longer upon the screen; we must, therefore, cause the machine so to recede or approach, that the two motions, being duly combined, the image may be distinctly formed.

These phantasmagoria are furnished with a great number of transparencies, in each of which, several changes may be made by slackening their springs. Thus we may change at every instant, the form, the magnitude, and the distance of the spectres, as they appear to the spectator.