Transparent stars with illuminated rays are formed, by making a strong circular block or body for the star, two feet in diameter, and attaching to it illuminated rays. In the centre of the front of the body, fix a spindle, on which put a double triangular wheel, six inches in diameter, clothed with two-ounce cases of brilliant charge. The cases on this wheel must burn only one at a time.

Round the edge of the body, nail a hoop made of thin wood or tin, which must project in front six or seven inches. In this hoop, cut three or four holes to let out the smoke from the wheel. The star may be cut out of strong pasteboard or tin in the following manner: Cut a round piece of pasteboard, two feet in diameter, on which draw a star, and cut it out. Over the vacancy, paste Persian silk, and paint the letters yellow; and also four of the rays yellow, and four red. This transparent star is to be fixed to the wooden hoop by a screw, to take off and on. The illuminated rays are made of thin wood, with tin sockets, fixed on their sides, within four inches of each other. In these rockets, put the illuminating port-fires, or lances; and behind the point of each ray, attach a half pound case of gray, black, or Chinese fire. The illuminated rays are to be lighted at the same time as the triangular wheel, or after it is burnt out. This may be done by a tin barrel, in the manner described in the regulated piece. Into this barrel, carry a leader from the illuminated rays, through the back of the star, which must be met by another leader, brought from the tail of the last case on the wheel.

The regulated illuminated spiral piece, with a projected star wheel, also illuminated, is made by procuring a block, eight inches in diameter, and putting in six iron spokes, which serve for spindles for the spiral wheels. These wheels are made one and a half feet in diameter, and three feet in height. The spindles must be of sufficient length to keep the wheels four or five inches from one another. At the end of each spindle, put a screw nut. On these spindles, the wheels, that hang downwards, are to run. On the spindles, which stand upwards, must be a shoulder, for the blocks of the wheels to run on. The projected star wheel turns on the same spindle on which the large block is fixed. This spindle must be long enough to admit the star-wheel to project a little before the spiral wheels. The exterior diameter of the star wheel is five feet five inches. On this wheel, three circles of iron wire are to be fixed, to which attach either port, or other illuminating fires. On the block, place a transparent star, or a large five-pointed brilliant star. The cases on this wheel may burn four at once. The cases on the spiral wheels must be placed parallel to their fells and burn two at a time.

In order to make a figure-piece, with five-pointed stars, illuminated, all that is necessary is to have a vertical wheel about one foot in diameter, and furnished with six four-ounce cases of different coloured charge, which must burn double. On the frame of the figure piece, fix five-pointed brilliant or blue stars, rammed four inches with composition. Let the space between each star be eight inches, and, at each point, fix a gerbe or case of Chinese fire. The gerbe, stars, and wheel are to be lighted at the same time.

The illuminated star wheel may be formed by procuring a fell about four feet in diameter, and placing, within this fell, three circles of iron wire, one smaller than the other, so that the diameter of the least may be about ten inches. Place the port, or other fires on these fells, with their mouths inclining outwards, and the port-fires on the points of the star, with their mouths projecting in front. The exterior fell must be clothed with four-ounce cases of gray charge. They must burn four at a time and be lighted at the same time with the illuminations.

The illuminated regulating piece as it is called, consists of flat wooden spokes, each five feet long, and at the end of each, a vertical wheel, ten inches diameter, and clothed with six four-ounce cases of brilliant fire. These cases burn one at a time. On two of the spokes of each wheel, two port-fires are attached, which must be lighted with the first case of the wheel. On each spoke, behind the wheels, place six cases of the same size with those on the wheels. These cases must be tied across the spokes with their mouths in one direction, and be made to take fire in succession.

The diameter of the large wheel must be two and a half feet, and its fell made of wood, which is to be fixed to the large spokes. Twenty-four cases of the same kind are fixed on this wheel, and burn four at a time. On the circles of iron-wire, already mentioned, illuminating port-fires are attached. The star-points on the large spokes may be made of thin ash-hoops. The diameter of these points, close to the centre wheel, is usually eleven inches. On these, port-fires are placed, three and a half inches distant from each other.

The illuminated double cone-wheel is nothing more than a double cone, formed of a number of hoops, and supported by three or four pieces of wood, in the manner of the spiral wheels. The wheel to which the cones are attached, base to base, is two feet six inches in diameter, and the height of each cone is three feet six inches. Port-fires, or lances, are tied to each of the hoops, in a horizontal direction, with their mouths outwards. The cases are eight-ounce, and play horizontally, two at a time. The spindle for this piece must rise three feet above the point of the cone at top; so that its length will be ten feet four inches from the top of the post, in which it is fixed, allowing four inches for the thickness of the block of the wheel. The whole weight of the wheel and cones must be made to bear on a shoulder in the spindle, on which the block of the wheel is to turn. On the top of the spindle, fix a sun, composed of sixteen four-ounce cases of brilliant fire. These cases must be stuck into a block, six inches in diameter. In the front of this sun, put a circular vertical wheel, sixteen inches in diameter. On the front of this wheel, form a spiral with wire, to which attach illuminations in the usual manner. This wheel is to be fired, when the cones are burnt out, which may be done as before described. The sun must not be fired, until the vertical wheel is burnt out. Three vertical wheels illuminated, which turn on their own naves upon a horizontal table, is a piece readily formed. It consists in having a table, three feet in diameter fixed horizontally on the top of a post, with three wheels that turn round on it. There are three spokes, joined to a triangular flat piece of wood, in the middle of which, a hole is made to fit easily over a spindle placed in the centre of the table. There are three pieces of wood four or five inches long, and two inches square, fixed on the under sides of the spokes. In these pieces, holes are made lengthwise, to receive the thin parts of the blocks of the wheels, which, when in, are prevented from coming out by a small iron pin that runs through the end of each. The three vertical octagon wheels, each eighteen inches in diameter, have blocks sufficiently long, for three or four inches to rest on the table. Round these a number of sharp points of wire are driven, (which must not project out of the blocks more than ¹/₁₆th of an inch), and the clothing is affixed in the usual manner. The use of the points is this, that, when the blocks turn round, they will stick in the table and assist in giving a uniform motion to the wheel. On the front of the wheels, make four or five circles of strong wire, or flat hoops, and tie, on these circles, as many illuminations, as they will hold, at two inches from each other. Spiral lines may be made instead of circles. When illuminations are fixed in a spiral line, in the front of a wheel, they ought to be placed on the slant. The cases for these wheels may be filled with any coloured charge, but must burn only one at a time. A globe, or spiral wheel may be put on the spindle, so that its fire may play over the vertical wheels. The wheels must be lighted at the same time, and the illuminations, after two cases of each wheel are consumed.

The vertical scroll wheel is formed by taking a block of a moderate size, and fixing in it four flat spokes, and, on them, a flat circular fell of wood. Round the front of this fell, port-fires are placed; and on the front of the spokes a scroll is formed either with a hoop or strong iron-wire. On this scroll, tie cases of brilliant fire in proportion to the wheel, head to tail. When the first case near the fell is lighted, the fire is communicated in succession. The grand volute, with a projected wheel in front, is made in the following manner: Two hoops are formed of strong iron wire, one of six feet in diameter, and the other of four feet two inches. These hoops must be joined to scrolls, formed according to fancy, of the same kind of wire. On these, tie, with iron wire, as many illuminating port-fires, as they will carry, at two inches distance. Prepare then a circular wheel of four spokes, three feet six inches in diameter, and, on its fell, tie as many four-ounce cases, head to tail, as will complete the circle, only allowing a sufficient distance between the cases, that the fire may pass free. On each spoke, fix a four-ounce case, about three inches from the fell of the wheel. These cases are to burn one at a time, and the first of them to begin with those on the fell, of which four are to burn at a time. On the front of the wheel, form a spiral line with strong wire, on which tie port-fires, with their mouths to face the same way as the cases on the wheel. All these port-fires must be fired with the second cases on the wheel.

The spokes of the wheel must be formed of wood, and made to screw into a block in the centre, and each spoke should be four feet six inches in length. In the top of each, fix a spindle, and, in each spindle, put a spiral wheel of eight spokes. The blocks of these wheels must have a hole at top for the centre cases, and the spindle must be furnished with nuts, screwed on their ends, which should fit in the holes at the top of the blocks. The cases of these wheels are to burn double; and the method of firing them, is by carrying a leader from each down the spokes into the block in the centre, as in the dodecaedron; but the centre cases of each wheel must begin with the two last cases as usual. The large circular wheel in front ought to have a tin barrel on its block; into which a pipe must be carried from one of the second cases on the wheel. This pipe, being met by another from the large block, in which the eight spokes are screwed, will fire all the spiral wheels, and the illuminating port-fires at the same time. The cases of the projected wheel may be filled with a white charge, and those of the spiral wheels with a gray.

Sec. XXI. Of the Spiral or Endless Screw, and Waved Fire.

This piece is formed in the same manner as the single and double cones; and, in fact, is the same as the Archimedean screw, which we have already described. The serpentine form which characterizes the spiral piece, is given to it by the particular arrangement of the lances of illumination. The cone receives its motion from the cases of white-fire; the fire of which is communicated by leaders to the cases of port-fire, or lances of illumination. They must burn the same length of time.

The waved fire is produced by having two wheels of a similar size, turning in a contrary direction on the same axis, and furnished with cases, which are inclined about 45 degrees from the level of the table. These wheels carry four cases each, and burn at the same time. They have been made to carry forty-eight cases, and furnished, at their centres, with lances, bent in a particular manner, so as to represent the motion of serpents.

Sec. XXII. Of the Decoration of Wheels.

Wheels, we have seen, may be made of different dimensions, according to the purpose to which they are applied. The most common are three or four feet in diameter, with a nave of hard wood, and spokes of light wood. They are sometimes surmounted with a fell, and frequently by several concentric hoops, placed at different distances from each other.

Wheels, in general, are furnished with cases, and various decorations. Some have two, three, four, and more fires; but, if they are finished too much, the weight they thus acquire would retard the velocity of the wheel. Their centres may be finished in several ways; as, for instance, by attaching, to the inner fells or circles, cases filled with white lance-composition, placed at the distance of two inches from each other, or alternately, white, blue, and yellow, or Chinese gerbes, or cases of blue fire. We may also attach small turning suns, the axes of which being placed upon the spokes. They may also be made to resemble a mirror, by furnishing all the spokes with white lances; and for the last fire, we may attach four cases to the centre, or in its vicinity, placed in such a manner, that their fire may issue from the interior of the wheel. To this, we may add, two other cases, which may cross the former. Leaders are fixed, and they are lighted at the same time.

Automatons with all their joints, or articulations, have been added to exhibitions of this kind, and with particular effect. They are clothed with cases after the usual manner.

Sec. XXIII. Of Globes, with their Various Decorations.

The first we purpose to treat of are the illuminated globes with horizontal wheels.

The hoops for these globes may be made of wood, tin, or iron wire, about two feet in diameter. For a single globe, take two hoops and tie them together, one within the other, at right angles; then have a horizontal wheel made, whose diameter must be a little wider than the globe, and its nave six inches long; on the top of which, the globe is fixed so as to stand three or four inches from the wheel. On this wheel may be put any number of cases, filled with any of the ordinary charges, as the white fire composition. Two of these cases must burn at a time. They may be placed horizontally, or inclining downwards. When the wheel is clothed, fix on the hoops as many illuminations as will stand, within two and a half inches of each other, which are fastened on the hoops with small iron wire. Attach the pipes of communication, and arrange them so as to carry the fire to all at the same time, with the exception of one or two, which are to receive their fire for the last. The spindle, on which the globe is to turn, must go through the block of the wheel up to the inside of the top of the globe; at this place must be fixed a bit of brass or iron, with a hole in it, to receive the point of the spindle, on which the whole weight of the wheel is to bear. When the globe is to be stationary and the wheel to run by itself, the block of the wheel must not be so long, or the spindle any longer than to raise the globe a little above the wheel.

We may remark, that, while the cases of white fire composition give to the piece a rotary motion, those of the lance or illuminating port-fire produce the effect, which characterizes in particular this fire-work.

With respect to fire globes, there are two kinds; namely, one with projected cases, and the other with concealed cases. If we have a globe made of wood, of any diameter, and divide its surface into twenty-four equal parts, and bore a perpendicular hole in each of these divisions to the centre, we may then represent this piece in the following manner: In every hole, except one, put a case filled with brilliant or any other charge, and let the mouths of the cases be even with the surface of the globe. Then cut in the globe a groove from the mouth of one case to that of another for leaders, which must be carried from case to case, so that they may all be fired together. The globe is then covered with a single paper and painted.

Fire globes with projected cases are made in the following way: Prepare a globe with fourteen holes, and fix in every hole except one, a case, and let each case project from the globe two-thirds of its length. Then clothe all the cases with leaders. It must be supported by a spindle made to fit the hole in which there is no case.

The bursting-globe is nothing more than a globe prepared in a particular way. It turns on a pivot, and is made by uniting four segments. These segments or parts are fixed to hinges, which open on the inside, and, when brought together, are kept in their place by a match which goes round the globe. The globe, it is to be observed, is furnished in the inside with several steel springs, which, unless the globe itself were tied, would force it open. When the match is burnt, this effect follows and the globe separates into four parts. It is furnished with lances and cases in the same manner as those already described. The last effect is that we have noticed.

Globes, which leap or roll on the ground, may be formed by procuring a wooden globe, furnished with a cylinder; and, having loaded it with the composition hereafter mentioned, introduce into it four or more petards loaded with grain powder to their orifices, which must be well stopped with paper or tow. If a globe prepared in this manner be fired by means of a match at the mouth of the cylinder, it will leap about as it burns on a smooth horizontal plane, according as the petards are set on fire. The petards may be affixed to the exterior surface of the globes, which they will cause to roll and leap as they catch fire.

Composition.

Sec. XXIV. Of the Representation of the Moon and Stars.

The moon and stars are represented in the following manner: Make a wheel eighteen inches in diameter, by fixing eight or more spokes in the nave; and then adapt a fell to it. To the fell fasten eight cases of the black or gray composition, and let the fire communicate from one to the other. These cases give motion to the wheel. Furnish the spokes of this wheel with cases charged with the white lance composition. Make now a crescent of iron and attach it to the spokes, or a little before the spokes of the wheel. In order to fix stars to this piece, eight strips of wood, seven feet in length, are made to cross each other at equal distances, and nailed to each other in the middle; so that when this frame is put behind and secured to the moon-piece, its arms will extend some distance beyond the perimeter of the wheel. These projections are furnished with five-pointed stars, eight inches apart, and there is usually in all thirty-two. They are made to communicate with each other by means of the cotton match, as before described. The light of the lances renders the moon very apparent, and the fixed stars resemble those in the firmament. The representation of the moon and seven stars may be performed by procuring a smooth, circular board, six feet in diameter. Out of the middle of it cut a circular piece twelve or fourteen inches in diameter, and cover the hole formed with Persian silk, on which is to be painted a moon's face. Also cut out of the board stars of four or five inches in diameter. These stars are cut out with five points and covered with oiled silk. On the front of the large circular board draw a seven-pointed star, as large as the circle will admit, and on the lines which form this star, make several perforations, in which six-pointed stars are to be fixed. A wheel of brilliant fire is placed behind the moon, which renders the moon and stars transparent. They will disappear when the wheel is burnt out; but then in consequence of the communication of the fire to the large star in front, which is formed of pointed stars, the appearance of this star succeeds, and finishes the piece.

A large fixed star may be made thus. To each extremity of the pieces of wood, arranged so as to cross each other, attach two cases of the black charge. Their fire must communicate. Near these cases, on each arm, place a turning sun of three cases. These five suns are fixed at the same time, and when they cease, the cases commence. These cases form the star.

The representation of flaming stars, with brilliant wheels, is made in the following manner. After procuring a circular piece of wood, about one inch thick, and two feet in diameter, fix round it eight points, each two feet and a half long, four of which must be straight and four waved, or flaming. These points being joined on very strong, and even with the surface of the wood, nail tin or pasteboard on their edges, from the wood to the end of each, where they must be joined. This tin is to project in front eight inches, and be joined where they meet at the block. Round the front of the wood, fix four pieces of thick iron wire, eight inches long each, equally distant from each other. Cut a piece of pasteboard round, two feet in diameter, and draw on it a star; then cut out this star, and on the back of it, place oiled paper. Paint half red and half yellow, lengthwise. The body of the star must be left open in which must be seen a brilliant wheel. This wheel is formed by having a block turned nine inches long, and fixing in it six spokes. At the end of each spoke, put a two-ounce case of brilliant fire. The length of these cases is made in proportion to the wheel, and the diameter of the wheel, when the cases are on, must be less than the diameter of the body of the small star. The cases on the spokes in front must have their mouths inclined outwards, and those on the inside spokes, placed so as to form a vertical circle of fire.

Carry the first leader, from the tail of one of the cases in front, to the mouth of one of the inside cases, and from the tail of that to another in front, and in the same order to all of them. Put on a spindle in the centre of the star. This spindle must be furnished with a shoulder at bottom, to keep the wheel at a little distance from the block, which is kept on the spindle by a nut at the end. Having fixed on the wheel, fasten the transparent star to four pieces of wire. When fired, a common horizontal wheel will only be seen; but when the first case is burnt out, it will fire one of the vertical cases, which will show the transparent star and fill the large flames and points with fire. It will then appear like a common wheel, and represent the same appearance for twelve changes.

With respect to the formation of stars for regulated pieces, we may remark, that they are made of different sizes according to the work for which they are intended. They are prepared with cases from one ounce to one pound; but, in general, with four-ounce cases, four or five inches long. The cases should be rolled with paste, and twice as thick of paper as a rocket of the same caliber. Having rolled a case, let one end of it be pinched quite close; then drive in half a diameter of clay, and, when dry, fill it with composition to two or three inches of the length of the case. At the top of the charge, drive some clay; as the ends of these cases, being seldom pinched, would be likely to take fire. Divide the case, when filled, at the pinched end close to the clay, into five equal parts; then bore five holes with a gimblet, about the size of the neck of a common four-ounce case, into the composition. From one hole to another, carry a quick match, and secure it with paper, in the same manner as the ends of wheel cases; so that the hollow part, which projects from the end of the case, may serve to receive a leader from any other work, to give fire to the points of the stars. These stars may be made with any number of points.

Sec. XXV. Of the Representation of Sundry Figures in Fire.

Animals and various figures may be represented in fire by the following method: Take sulphur, reduced to a very fine powder, and, having formed it into a paste with starch, cover the figure of the thing to be represented, with this mixture, having first coated it with clay to prevent it from being burnt. After the figure is covered with paste, it must be sprinkled, while moist, with gunpowder; and, when the whole is perfectly dry, arrange about it several small matches, that the fire may be speedily communicated to it on all sides. In this way, all sorts of garlands, festoons, and other ornaments may be imitated by fire of different colours.

A shower of fire may be connected with this representation, by using cases of one-third of an inch in diameter, charged with any of the following compositions. These cases should be two inches and a half in length. They must not be choaked, it being sufficient to twist the end of the cartridge. The effect of these cases is to fill the surrounding air with an undulating fire. The compositions are similar to those already noticed; viz. for Chinese Fire, take gunpowder one pound, sulphur two ounces, pulverized cast-iron of No. 1. five ounces; for ancient fire, meal-powder one pound, charcoal two ounces; and for brilliant fire, meal-powder one pound, and iron filings four ounces. Sparks are also sometimes employed. These are made in the usual manner.

Besides the common mode of forming sparks, as they differ from stars only in their size and duration, (being formed into small balls about the size of peas), they may be made by the following method: Take sawdust of fir, poplar, &c. and boil it in water, in which saltpetre has been dissolved. When the water has boiled some time, it is to be poured off, that the sawdust may remain in the vessel. When nearly dry, spread it out on a table, and sprinkle it with sulphur, sifted through a very fine sieve, to which may be added a little meal-powder.

If it be required to accompany the exhibition with bearded rockets, (fusées chevelues of the French), so called from the circumstance, that, when they fall, they make small undulations in the air like frizzled hair, we may form them in the following manner: Fill the barrels of some goose-quills with the composition of sky-rockets, and place upon the mouth of each a little moist gunpowder, both to keep in the composition, and to serve as a match. If a flying-rocket be then loaded with these quills, they will produce, at the end, a beautiful shower of fire.

Sec. XXVI. Of the Representation of Flat Stars, with a large Body of Fire.

A star of five points, about two feet from point to point, is to be made, and, in its centre, is placed a turning sun, composed of three cases, and altogether not more than six or eight inches in diameter. To this star five branches are fixed, each of which is three feet in length; and, to the extremity of each, are attached seven cases, with their mouths outwards, and inclining about thirty-five degrees. One case is then attached lengthwise, and forms the very extremity of each projection. On each leg or branch, nearer, however, the centre of the star, must be three cases, fixed in an hexangular form. The border of the large star is decorated with Italian or fixed stars. The fire is communicated to the star by means of a leader, then to the sun and the cases on the branches.

Sec. XXVII. Of the Single, Double, and Triple Table Wheel.

We have spoken of an arrangement of fire-works, which moves a wheel on a circular board. That contrivance is similar to the one we now purpose to describe.

The table-wheel is a kind of girandole, which turns circularly on a round table, by having its axis connected with a perpendicular pin, fixed in the table; so that its motion is vertical, while it moves in a circular position round the table.

The table, as well as the wheel, may be of any size, according to fancy. Eight or nine cases are usually attached to the fell of the wheel, and in the direction of the fell. These cases turn it with great velocity. The centre of the wheel may be decorated with lances, or illuminating port-fires. When double or treble wheels are to be arranged on the same table, this is done by having the iron so lengthened, as to extend over the table, and receive another wheel of the same size; and by using a contrivance of iron, having three projections, at equal distances apart, and turning in the same manner on a pivot, or pin, fixed in the centre of the table, three wheels may be put in motion at the same time. When two wheels are employed, we may decorate one with blue lances, and the other with yellow. When three wheels form the same piece, it is usual to illuminate them, severally, with white, blue, and yellow lances. The wheels of coloured fire augment the beauty of the exhibition. In the centre of the table, may be placed a pyramid, decorated in the usual manner. Spiral wheels, globes, &c. may be attached, if so required.

Sec. XXVIII. Of Decorations, Transparencies, and Illuminations.

Cut-work, as it is called, is often employed in decorations. Various figures, letters, garlands, &c. may be represented. This may also be accomplished in tambour-work. Several methods have been used to produce the same effect. Cut-work, made in pasteboard, and the pasteboard blackened and suspended in a frame, will, by the aid of lights placed behind it, exhibit the design very perfectly. A figure of a sun cut out of pasteboard, either fixed or made to revolve in the manner before described, and illuminated by fixed lights or revolving cases, is considered to be the best mode of forming such pieces. In all instances, the more brilliant the fire, the more perfect is the representation. Tambour decorations are variously arranged; and, frequently, in the termination of an exhibition, six or more are shown at once, and sometimes with cascades, and turning suns.

In the place of cut-work, painted transparencies, made with fine colours, and on Florence Taffeta, are usually employed. Transparent paintings however, are not preferred by some, as the effect, it is said, is not so perfect as when cut-work is employed. Morel gives a preference to the latter.

Transparencies may be formed with silk, or fine linen, and even with paper, if previously prepared, by means of the spirit of turpentine. The colours are painted in turpentine, and transparent varnish is then applied.

Transparent screens may be prepared, by spreading white wax, dissolved in spirits of turpentine, over thin muslin. A screen, thus prepared, will roll up without injury. A clearer screen may be produced, by having the muslin stretched upon a rectangular frame, and prepared with turpentine instead of wax.

In the Œuvres de Diderot, t. xv, p. 349, are observations respecting transparencies, and the manner of preparing them. The process described is nothing more than we have noticed. It consists in using the oil of turpentine, and sometimes a solution of wax in turpentine. The colours are prepared mostly with turpentine. Canada balsam, thinned by the addition of the spirit, is also employed. Moveable transparencies were exhibited with great effect in Paris. Transparent figures were made to move continually in every direction, which had a singular appearance. Artificial fire-works were very accurately imitated, by producing a variety of movements with different pieces of transparencies, variously coloured. The sun, moon, and stars, revolving wheels, &c. composed a part of this exhibition.

With respect to decorations in white and coloured lances, we may observe, that artificial fire-works are usually terminated by some decoration, which corresponds with the subject. For this purpose, triumphal arches, fronts of palaces, colonades, rocks, &c. are formed, and represented in wood-work. These are usually clothed, and painted in water-colours. From the rocks, water is made to issue, forming cascades, and a number of figures are put in motion. The jets of water are terminated by jets of Chinese fire, or brilliant fire-rain.

The furniture, or decorations, may be various, either with white or coloured lances of illumination, hung four inches apart, and attached to different parts of the figure, or building. If it is in front of a temple, the columns are ornamented with emblems, &c. the fire-work being thus arranged: viz. blue lances are attached to the columns, white lances to their entablature, and to the emblems, yellow lights. This however, depends on taste.

Decorations are also made with matches; but this mode is not preferred, because so much smoke is thereby produced.

Figures, cut in paper, are illuminated in the manner before described. But for this purpose, muslin is first stretched on a frame, and its sides are covered with two or three thicknesses of paper, which are pasted on. It is then blackened. After tracing the design, or the subject of the illumination, and cutting it out with exactness, the frame is put in a case, sufficiently deep to contain a number of lights.

Illuminations, as an expression, of public feeling for some event or memorable occasion, are by no means a recent thing. Various modes have been adopted to render such exhibitions more elegant, as well as more expressive. Hence, with the usual display of lights, arranged according to taste and fancy, transparencies, decorations, such as we have described, &c. have been more or less customary.

We mentioned, in the first part of our work, something in relation to the antiquity of illuminations; but, as this subject may be interesting, we deem the following brief remarks not irrelevant.

Beckman assures us, (History of Inventions), that the origin of illuminations is very ancient. The feasts, or holy-days were celebrated in the days of antiquity, in various ways, among which, that with lamps was very common in Egypt. It was called the feast of the lamps, (Fête des Lampes), and the inhabitants of some cities in Egypt were obliged to illuminate, with a great number of lamps, placed before their houses. Herodotus (lib. ii, chap. 62), remarks, that, at a particular festival of the Egyptians, lamps were placed before all the houses throughout the country, and kept burning the whole night. During the festum encæniorum, the Feast of the Dedication of the Temple, which, according to common opinion, was celebrated in December, and continued eight days, a number of lamps were lighted before each of their houses. Such illuminations were used, also, in Greece and Rome, and were called Lampadaria. An infinite number of lamps were burnt in honour of Minerva, Vulcan, Prometheus, Bacchus, &c. On the last occasion, the illumination was called Lamptericæ. It seems that the lighting of streets had not been adopted at that period.[25] At Rome, the forum was lighted, when games were exhibited in the night-time; and Caligula, on a like occasion, caused the whole city to be lighted. As Cicero was returning home late at night, after Cataline's conspiracy had been defeated, lamps and torches were lighted in all the streets, in honour of that great orator. The emperor Constantine caused the whole city of Constantinople to be illuminated with lamps and wax candles on Easter-eve. The first christians often illuminated their houses on idolatrous festivals, in a more elegant manner than the heathens. This was dictated by policy. The houses of the ancients were illuminated on birth-days, by suspending lamps from chains.

For illuminations at the present day, tallow is chiefly used. It is clarified, for the making of candles, by means of alum. M. Olaine in 1710 presented to the academy of sciences an apparatus for the manufacture of candles. The bougie economique of the French is described in the Journal de Paris for 1782. The outline of the process for preparing them is as follows: Take eight parts of suet, and melt it with one quart of water; and after straining it, and returning it to the same boiler, add the same quantity of water, in which was dissolved half an ounce of saltpetre, as much sal ammoniac, and one ounce of alum. The boiling is continued to evaporate the water. The wick is made of cotton or flax, and rolled in a solution of camphor in petroleum, and afterwards covered in the usual manner with the above composition.

In using tallow generally, quicklime is recommended to be added to it in fusion. When the quicklime subsides, it is poured off. Another mode recommended is to melt the tallow with vinegar, and to add to it a decoction of rosemary, sage, laurel, and a small quantity of turmeric; the whole being boiled until the water is evaporated. This communicates, it is said, an agreeable odour, and a yellow colour. Different modes of preparing tallow for candles have been used. See sal ammoniac. With respect to ancient lamps, some account of them has been published in the Antiquities, by Montfaucon and by Passeri; and the Journal des Savants 1682 and 1685 mentions the two lamps of Boyle and Sturmius, and some account of the celebrated lamp of Callimacus in the temple of Minerva. On the formation of lamps, and the purification of oil, sundry patents have been granted both in France and England. The argand lamp for burning its own smoke, which it effects by a glass cylinder placed over the flame, is one of the best improvements of the kind. The principle of these lamps is the same, although variously modified in shape and structure. For chemical purposes, an iron cylinder is substituted for glass. A lamp, for the burning of tar and turpentine, with steam, has lately been invented by Mr. Morey, (see Silliman's Journal Vol. II.) Mr. E. Clarke obtained a patent for a lamp calculated to burn tallow; the principle of which is, that by the heat of the flame, the caloric is conducted to the tallow by means of a piece of iron, which is heated by it, and the tallow melts as it is wanted. This lamp may be economically used, when common lamp oil is scarce and high in price. A lamp is described in the Repository of Arts, to burn tallow.

As a wick, besides cotton, several substances have been recommended. The filaments of amianthus, for instance, while they perform the office of a wick, are incombustible. The Journal de Verdun for 1748, announced incombustible wick by sieur Lespar. Touch wood, the tussilago sarfara, and the verbascum tapsus of Linnæus, are also recommended. In 1783, Leger announced, in the Journal de la Blancherie, that he had invented a match which would burn without smoke and odour.

Lamps have been furnished with fixed and moveable mirrors, to throw the light forward by reflection. The reverberatory lamps, revolving lights for light houses, &c. are of this kind. Many patents have been obtained for such contrivances, which we have not room to notice.

The inflammable air lamp for the table, described in the Dictionnaire de l'Industrie, is nothing more than a spirit of wine lamp, and used in lieu of hot bricks, or vessels filled with boiling water for the warming of dishes, &c. In 1780, M. Ehrman, in his Description et usage de quelques lampes à air inflammable, describes a chafing dish with inflammable air, invented by Nevet, which operates by the combustion of hydrogen gas.[26]

Fixed illuminations are more brilliant and more magnificent; as the lights are more numerous, as well as more diversified. Wax, spermaceti, or tallow candles, or oil burnt in tin lamps, or in glass cups suspended by wire, are all used for the purpose. If the wick be dipped in spirit of turpentine, it will take fire instantaneously. It is unnecessary to make any remarks as to the arrangement of lights.

Large dishes containing melted tallow, and a wick proportionally thick and suspended by means of a simple contrivance of tin, are recommended for the same purpose. Coloured lights afford a variety. The appearance of coloured flame may be produced by burning the oil in coloured glasses, so disposed as to let the light pass through the glass, or by placing lamps behind bottles filled with coloured water.[27]

The coloured glasses which are sold in Paris for the purpose, are formed with facets on the outside, which not only produce the appearance of coloured flame, but also, according to the number of facets, the refraction and reflection of the light. Arches, pyramids, obelisks, &c. are lighted up in this manner.

The Pont Neuf, and the Seine in 1739, were illuminated at the time of the splendid exhibition of fire-works. It is unnecessary, however, to particularize on this head. We all remember the splendid illuminations in all our cities during the late war, which were indeed a true expression of our national and individual feeling. Illuminations, in this country, before that time were very rare; none we think since the peace of 1783, and the union under the federal compact.

Phosphuret of lime, of the size of peas, thrown into water, will afford, at short intervals, a brilliant flame of fire; for the phosphuretted hydrogen gas thus produced has the property of inflaming spontaneously in atmospheric air. Alcohol, containing sundry salts in solution, will give a flame of various colours, according to the salt it holds in solution. See Alcohol.

Illuminated works are much admired by the Italians, and particularly the Illuminated chandelier, which is considered a great addition to a collection of works. An illuminated chandelier is formed of thin wood with arms extending on each side. Holes are bored in the front of the branches and in the body, and also in the eagle (if it be added,) at top, and distant from each other about three inches. In these holes, we put illuminations, filled with white, blue and brilliant charge. Having fixed in the port-fires, they must be clothed with leaders, so that the chandelier and eagle may light together.

We may also observe, that, for the speedy lighting of a number of lamps, at one and the same time, quick-match enclosed in paper tubes has been used. This quick-match is sometimes made to communicate its fire to a sulphur match, prepared by dipping strands of cotton in melted sulphur, and from this to the lamp. Several methods are recommended for this purpose; one of which consists in dipping cotton wick in the oil of spike, and arranging it along the wicks of the different lamps, so that when inflamed the fire may pass rapidly from one lamp to another. In 1772, M. Renault, a Parisian, announced in the public papers, that he possessed a secret, by which he could light 2000 lamps in five minutes, by means of a match of communication.

We have some experiments and observations on coloured flame, by Mr. Morey, in his essay on heat and light, in the second volume of Silliman's Journal of Science and Arts, p. 120. The experiments are curious, and worthy of remark. If water, he observes, be put into one cylinder, and made to boil, and the steam be led to the bottom of another included cylinder, containing spirits of turpentine, the steam, when let out under a moderate pressure, carries off with it a sufficient quantity of the spirit to burn with a pleasant white flame, free from smoke; but if the pressure be increased, the flame will become in part or wholly blue. "Here," he adds, "as in many other experiments, I have noticed, that different coloured flames may be produced from the same materials—are the products of combustion different?" He further observes, that "if the steam of water, containing a small proportion of the vapour of rosin, be driven against iron, at or below a red heat, it burns with a pleasant blue flame, which will be extended some way back into the column of the vapour, intermixed with innumerable sparks of very white flame, evidently particles of the rosin. If the vapours, when the proportion of the rosin is very small, are made to pass between two plates of iron, at or near a red heat, they can be inflamed on the opposite sides of the plates, and will then, sometimes, burn with an entirely blue flame, although the vapour can not be inflamed, without the intervention of the plates." He states other experiments, made with tallow and steam, producing a blue flame. The blue colour seems to be owing to the pressure made use of; for, in his second communication, (page 122, of the same volume), he mentions white flame being produced by the vapour of water; and when it is in a sufficient quantity, there is no smoke. If too great, combustion ceases. Speaking of the colour of the flame, produced by mixed vapours, (of the combustible and water), such as blue, blue and white, white and intense white, he adds, that they may be imitated, at pleasure, with the patent lamp stove, by burning tar, pitch pine, or mineral coal and water. Newly made charcoal will take up about three times its weight of water. "Sand, ashes, or fine clay," he observes, "answers well for mixing with the tar, &c. If the latter be made into a paste with equal parts of spirit of turpentine and water, and cold lumps of it, of a conical form, be placed on a table, and a flame applied, the vapours burn without smoke for a short time, &c. If enclosed in a tin cylinder, and the vapour be made to issue through small holes at the top, placed as before stated, or on a plate over a chafing dish of coals, it burns with a very bright light, free from smoke. If the cylinder be tight at the top and the vapour be led from the inside at the top, down and through the bottom, and there be made to issue in an oblique direction, and from a number of small openings, it will burn with a beautiful flame and supports and regulates, very accurately, its own evaporation. The oblique direction carries the heat, in part, beyond the cylinder, when the evaporation is too great.

"Every effect may be produced in consuming the smoke, and giving an intense white flame, by using a certain proportion of water, intimately blended or mixed with these vapours, that can be from an access of oxygen furnished, by creating a very strong current of air, with a high flue." The description of Morey's lamp stove, may be seen in the same work. The steam, he observes, may be furnished by a small tin boiler, and directed to or near the bottom of the tar. An intense white flame free from smoke, may be thus produced from tar, rosin, rough turpentine or the spirit, alcohol, oil, fat, tallow, mineral coal, pitch pine wood, and the knots, birch bark, and pumpkin, sun-flower, flax, and other seeds. With regard to pine wood, he adds, it is the easiest managed, evaporates at a lower temperature, consumes a greater proportion of water in its combustion, contains the water within itself, and gives a brighter light than common candles or lamps, and without smoke. The more volatile parts are evaporated at a temperature below that of boiling water, and burn well with three parts of the vapour of water; the flame then, however, is nearly blue. Observations on the application of this mode of producing light and heat, may be seen in Silliman, p. 131, &c. It appears, that Gay-Lussac (Annales de Chimie, for June, 1819,) has commented on Mr. Morey's plan.

Professor Hare (Silliman's Journal, vol. 2d, p. 172) also observes, that the flame of hydrogen gas is rendered luminous, like that of oil, by adding a small quantity of oil of turpentine to the usual mixture for generating this gas; and that the addition of ¹/₁₇ of the same fluid to alcohol, will give it the property of burning with a highly luminous flame; and there is a certain point in the proportions, at which the mixture burns without smoke, like a gas light. In the first instance, he observes, when the ingredients are at the proper temperature, the light is greater than that produced by carburetted hydrogen gas. Speaking of this application of spirits, the professor judiciously adds: "It might be serviceable to morals, if the value of this article could be enhanced by a new mode of consumption." We find, also, that the effect of vapour on flame has been noticed by Dr. Dana, in the same Journal, vol. 1, p. 40; by which it appears, that when a jet of steam is made to pass into a charcoal fire, the vividness of the combustion is increased, and also the low attenuated flame of the coal; that it prevents the smoke of a common oil lamp, and makes the flame brighter; that the flame of spirit of turpentine, which is usually dull and reddish, is rendered bright, and no smoke is formed; or when the vapour of both are made to issue together from the same orifice, and inflamed, no smoke appears; that a jet of steam, thrown into the flame of a spirit of wine lamp, or into flames which evolve no smoke or carbonaceous matter, produces the same effect as a current of air; but that, in all flames which evolve smoke, steam produces an increased brightness and a more perfect combustion. Dr. Dana further suggests, that steam might be introduced into the flames of street lamps, which might be so contrived as to keep water boiling, to produce the steam, and thereby cause a more perfect combustion, and a greater quantity of light from the same materials.

Count Rumford has shown, that the quantity of light, emitted by a given portion of inflammable matter in combustion, is proportional, in some high ratio, to the elevation of temperature; and that a lamp, having many wicks near each other, so as mutually to increase their heat, burns with infinitely more brilliancy than the Argand lamps in common use. To measure the proportional intensities of two or more lights; place them a few inches asunder, and at the distance of a few feet or yards from a screen of white paper, or a white wall. On holding a small card near the wall two shadows will be projected on it, the darker one by the interception of the brighter light, and the lighter shadow, by the interception of the duller light. Bring the fainter light nearer to the card, or remove the brighter one further from it, till both shadows acquire the same intensity. Measure now the distances of the two lights, from the wall or screen, square them, and you have the ratio of illumination. Thus, if an Argand flame and a candle, stand at the distances of 10 feet and 4 feet, respectively, when their shadows are equally deep, we have 10² and 4², or 100 and 16, or 6¹/₄ and 1, for their relative quantities of light.

The author of the Dictionnaire de l'Industrie, vol. iii, p. 365, in treating on the subject of illumination, mentions different modes of illuminating, both with and without transparencies. We know that various mixtures will produce different coloured flame. Thus, arsenic will burn with a beautiful white flame in oxygen gas; iron and steel will burn also, affording a brilliant light; phosphorus and charcoal with a white, and sulphur with a beautiful blue flame; zinc with a green colour, &c.

Again, we know that a mixture of nitrate of strontia and charcoal will burn with a rose coloured flame; one part of boracic acid, and three of charcoal, with a green flame; one of nitrate of barytes, and four of charcoal, with a yellow flame; and equal parts of nitrate of lime and charcoal powder, with an orange flame. We also know, that cotton dipt in oil of turpentine, or ardent spirit, rosin, camphor, &c. will burn extremely vivid and beautiful.

The author, whom we have just quoted, gives some remarks on the various coloured flames, that may interest the reader.

Felt (Feutre, Fr.) he remarks, if put in the fire, will give most beautiful colours, a golden yellow and a brilliant blue. And this, he adds, may be proved by throwing pieces of old hats into the fire; for these colours depend on the substances used in dying the hat. He further remarks, that green oak wood gives a yellow flame, and alcohol with sedative salt, (boracic acid), a blue, and that, by uniting the flame of both, the product, as to colour, will be a green.

The flame of alcohol is changed of various colours, according to the salt it holds in solution. Of this circumstance, Schatt was apprised, when he gave some formula many years ago, on the manner of forming coloured flame. Reaumur remarked also, the different colours which some metals assume, when submitted to the action of heat, which is known now to be the effect of oxidizement.

As respects the phenomena with felt, we are told, that, if we throw into the fire the cuttings of hats, we will perceive at first a white flame, and then in succession a blue, green, and violet colour; all which, our author observes, proceeds from the verdigris and other substances, employed in the composition of the dye stuff. There is one fact, which he has asserted, which may probably be explained on the materiality of light, so far as regards the formation of colour, (not considering, however, the theory of Bancroft, given in his Philosophy of Permanent Colours, or the more philosophical one of Dr. Samuel Conover, of Philadelphia, in the Transactions of the American Philosophical Society), and this fact is, that the flame carries the colour to the object which it illuminates, and that the object itself actually partakes of the colour, in order to produce any particular appearance. That colours, as visible to the eye, are all formed in the solar light, and their appearance depends upon the absorption of some of the rays of light, and the reflection of others, is a doctrine which followed the discoveries of Sir Isaac Newton. We have not room to notice this subject, however interesting it may be in a philosophical point of view.

There can be no doubt, that the art of colouring flame was known for a long time. We are told, that the philosopher Anaxilaus even pretended, that, by putting ink with the oil of a lamp, or the liquor of the cuttle fish, the faces of the bystanders will appear black by the light of this lamp! Sulphur has the effect of rendering the visage pale and cadaverous. Other persons, as Simon Sethe, advanced an opinion, that, if we moisten the wick of a lamp with ink, or in a mixture of the rust of copper, and having lighted the wick, and placed other lights around it, the faces will appear, some black, and some of a brass colour. Others, such as Cardan, say, that, by making a mixture of wine and salt, and then reducing it two-thirds by evaporation, the flame, which the wine will then give, will make the living put on a cadaverous appearance, if they remain in one posture. Malina also observes, that, by burning a piece of woollen cloth well soaked in a solution of salt in vinegar, the visage will appear frightful by the light of the flame. But the process of J. B. Porta is not less worthy of note. If good old wine, he observes, be put into a bowl with a handful of salt, and set on live coals, but not in the flame, and as soon as it begins to boil, is set on fire, (the other lights in the room being extinguished), the figure of each person will appear so hideous, as to produce a mutual dread. The author of the Dictionnaire de l'Industrie, iii, p. 433, observes, that he has repeated this experiment, sometimes with brandy, and at other times with alcohol, with perfect success.

A cadaverous appearance is said to be given, by mixing common salt with alcohol, in which some saffron had been infused. When set on fire, and the other lights extinguished, the effect, we are told, is very striking.

The so called miraculous luminaries, are nothing else than solar phosphori, which are very numerous. Their effect is to emit light in the dark, but not heat. Almost every thing in nature possesses this property in a greater or less degree, which depends on the absorption and subsequent transmission of light. The eyes of various animals have this property; cats and owls in particular. Snow possesses it in a considerable degree. Putrid animal matter, fish, for example, rotten wood, &c. partake also of this property.

It may not be improper to notice, in a general way, some of the substances, which are denominated solar phosphori. The Bolognian phosphorus is the calcined baroselenite, (sulphate of barytes), which, when exposed a few minutes to the light, shines when taken into the dark like burning coals. In water it emits the same light. This property, as is the case with all other solar phosphori, it loses gradually; but by heating it again, imbibes light. Canton's phosphorus is calcined oyster shells. It is used in the same manner. Baldwin's phosphorus is fused nitrate of lime. Various saline and other bodies, as diamonds and precious gems, possess the same property. Expressed oils and animal fats, when heated to 450°, become phosphorescent.

Hanzelet (Traité des Feux d'Artifice) remarks, that a stone may be made to give light by water, if prepared in the following manner. Take quicklime, tutty, and saltpetre, of each one part; reduce them to powder, and expose them to the action of heat. On the addition of water, light is said to be given out.

When quicklime is mixed with essential oil, and brought in contact with water, spontaneous combustion is said to take place.

Fluor or Derbyshire spar, (fluate of lime), when pulverized and heated to 212° Fahr., and then removed to the dark, is very luminous. If writing be made on a copper or iron plate, with thin mucilage or white of egg, and powdered fluor spar, sprinkled on it; when the plate is removed to a gentle coal fire, the delineated objects will become luminous, and opaque again when the plate becomes cold. The lapis lazuli has the same effect.

The phosphoric substances, which become luminous by attrition or percussion, are numerous. Homberg's phosphorus, which is nothing more than calcined muriate of lime, is of this character. When struck it emits light. Without either light or fire, a number of bodies will give out light. Flints, and other siliceous stones, struck against one another, appear luminous in the dark. Various other minerals have the same property. Wedgwood (Phil. Trans. 179,) Coates (Nich. Jour. 1799,) Westrumb (Crell's Chem. Annals, 1784,) have written on this subject; to which enumeration we may add the interesting remarks of Dr. Hulme, (Phil. Trans. 1800,) and the observations of Cabarris, in his Memoir, read before the National Institute.

It may be sufficient to remark, that the shell-fish called pholas; the meduca phosphorea, and other molluscsæ; several insects of the species fulgora, or lantern-fly; the lampyris, or glowworm; the scolopendra electrica; the cancer fulgens; the medullary substance of the human brain, &c. are all phosphorescent.

M. Dessaignes (Bulletin de la Société Philomatique, Octobre, 1810) made a number of experiments on solid, liquid, and aeriform bodies, relative to the disengagement of light by compression. Among other conclusions, he adds, that water is the cause of the spontaneous phosphorescence of bodies, such as quicklime, Canton's phosphorus, dry muriate of lime, &c. all which, when brought in contact with water, emit light, which he attributes to the consolidation of that fluid. The absorption of moisture, and its subsequent consolidation, may, in some instances, give rise to luminous appearances.

The lapis solaris, Bolognian stone, or the present sulphate of barytes, was discovered in 1602, by Casciorolus, a shoemaker of Bologna. He came to Scipio Begatello, who at that time was particularly known by his attachment to the art of gold-making, and showed him this stone, under the mystical name of lapis solaris, on account of its attracting the golden light of the sun, and its boasted fitness for converting the semi-metals into gold, the sol of the alchemists!

Dr. Brewster (Edinburgh Philosophical Journal) made a number of experiments on the colour and intensity of light, evolved by different minerals, by which it appears, that the yellow sulphate of barytes gives a pale light, while fluate of lime, a blue and green light. Cellini (Treatise on Jewelry, published near the beginning of the 16th century) was the first who observed the phosphorescence of minerals; it does not appear that he knew of the Bolognian stone. Grimshire (Nicholson's Journal, 8vo. vols. 15, 16, 19,) made a number of experiments on the emission of light by bodies, when subjected to the electrical influence; and, when thus treated, sulphate of barytes gave a brilliant green light.

The cawk of the miners, as it is also a sulphate of barytes, phosphoresces when previously exposed to heat.

There are two water fountains, both set in motion by the action of heat on confined air, which, as it expands, forces the water from an under vessel in jets. The first is called the illuminated fountain, and plays when the candles are lighted, stopping when they are extinguished. The other is a fountain, which acts on the same principle, but by the heat of the sun. The effect of the first is more or less considerable according to the pressure of the air upon the water, and consequently, to the degree of rarefaction which the air undergoes.

The chemical illumination of some writers, by using oil of vitriol, iron filings, and water, and inflaming the vapour as it proceeds from a bottle, is nothing else than the inflammation of hydrogen gas. The "white vapours," which they describe, is the gas in question.

Having noticed the use of candles and lamps for illumination, we purpose, in concluding this article, to give the result of some experiments on the relative intensities of light, and duration of different candles, made by Dr. Ure, which we extract from his Dictionary of Chemistry.

The doctor remarks, that ¹/₈th of a gallon of good seal-oil, weighs 6010 gr. or 13 and ¹/₁₀th oz. avoirdupois, and lasts, in a bright argand lamp, 11 hours 44 minutes. The weight of oil it consumes per hour, is equal to four times the weight of tallow in candles, 8 to the pound, and three and one-seventh times the weight of tallow in candles, 6 to the pound. But its light being equal to that of 5 of the latter candles, it appears, from the above table, that 2 lbs. weight of oil, in an argand, are equivalent, in illuminating power, to three pounds of tallow candles. The larger the flames in the above candles the greater the economy of light.[28]

Sec. XXIX. Of Imitative Fire-Works.

Imitative fire-works are nearly of the same character as the transparencies and illuminations mentioned in the last section; but, as this subject may be interesting to some of our readers, we thought proper for that reason to appropriate a section to its consideration.

Imitative fire-works are formed in the following manner: Take a paper that is blacked on both sides, or instead of black, let it be coloured on each side with a deep blue, which will be still better for such as are to be seen through transparent papers. It must be of a proper size for the figure intended to be exhibited. In this paper, cut with a pen-knife several spaces, and with a piercer make a great number of holes, rather long than round, and at no regular distance from each other.

To represent revolving pyramids and globes, the paper must be cut through with a pen-knife, and the space cut out between each spiral should be three or four times as wide as the spirals themselves. They must be so cut, that the pyramid or globe may appear to turn on its axis. The columns that are represented in pieces of architecture, or in jets of fire, must be cut in the same manner as if they are to be represented as turning on their axis.

In like manner may be exhibited a great variety of ornaments, cyphers, and medallions, which, when properly coloured, cannot fail of producing a most pleasing effect. There should not be a very great diversity of colours, as that would not produce the most agreeable appearance.

When these pieces are drawn upon a large scale, the architecture or ornaments may be shaded; and to represent different shades, pieces of coloured paper must be pasted over each other, which will produce an effect that would not be expected from transparent paintings. Five or six pieces of paper, pasted over each other, will be sufficient to represent the strongest shades. To give these pieces the different motions they require, we must first consider the nature of each piece: if, for example, we have cut out the figure of the sun, or of a star, we must construct a wire wheel of the same diameter with those pieces. Over this wheel a very thin paper is to be pasted, on which is drawn with black ink the spiral figure. The wheel thus prepared, is to be placed behind the sun or star, in such a manner that its axis may be exactly opposite the centre of either of those figures. This wheel may be turned by any contrivance.

Now, the wheel being placed directly behind the sun, for example, and very near to it, is to be turned regularly round and strongly illuminated by candles placed behind it. The lines that form the spiral will then appear through the spaces cut from the sun, to proceed from its centre to its circumference; and will resemble sparks of fire that incessantly succeed each other. The same effect will be produced by the star, or by any other figure, where the fire is not to appear as proceeding from the circumference to the centre.

These two pieces, as well as those that follow, may be of any size, provided we observe the proportion between the parts of the figure and the spiral, which must be wider in large figures than in small. If the sun, for example, have from six to twelve inches diameter, the width of the strokes that form the spiral need not be more than one-twentieth part of an inch, and the spaces between them that form the transparent parts, about two-tenths of an inch. If the sun be two feet in diameter, the strokes should be one-eighth of an inch, and the space between, one quarter of an inch; and if the figure be six feet in diameter, the strokes should be one-fourth of an inch, and the spaces, five-twelfths of an inch. These pieces have a pleasing effect, when represented of a small size; but the deception is more striking when they are of larger dimensions.

It will be proper to place these pieces, when of a small size, in a box quite close on every side, that none of the light may be diffused in the chamber; for which purpose it will be convenient to have a tin door behind the box, to which the candlesticks may be soldered, and the candles more easily lighted.

The several figures cut out should be placed in frames, that they may be put alternately in a groove in the forepart of the box, or there may be two grooves, that the second piece may be put in before the first is taken out.

The wheel must be carefully concealed from the eye of the spectator. Where there is an opportunity of representing these artificial fires by a hole in the partition, they will doubtless have a much more striking effect, as the spectator cannot then conjecture by what means they are produced.

It is easy to conceive, that, by extending this method, wheels may be constructed with three or four spirals, to which may be given different directions. It is manifest, also, that, on the same principle, a great variety of transparent figures may be contrived, which may be all placed before the same spiral lines.

In representing cascades of fire, it is necessary to observe, that, in cutting out the cascades, care must be taken to preserve a natural inequality in the parts cut out; for if to save time, all the holes are made with the same pointed tool, the uniformity of the parts will produce a disagreeable effect.

To produce the apparent motion of these cascades, instead of drawing a spiral, a slip of strong paper is to be provided, in which there must be made a great number of holes near each other, and made with pointed tools of different dimensions.

At each end of the paper, a part, of the same size with the cascade, must be left uncut; and towards those parts the holes must be made a greater distance from each other.

When the cascade that is cut out is placed before the scroll of paper just mentioned, and it is entirely wound upon the roller, the part of the paper that is then between, being quite opaque, no part of the cascade will be visible; but, as the wheel is turned gently and regularly round, the transparent part of the paper will give to the cascade the appearance of fire that descends in the same direction; and the illusion will be so strong, as to appear as a real cascade of fire.