Chapter III: Part 3

Take three parts of saltpetre, two parts of salt of tartar, and one part of sulphur pounded and mixed together; heat sixty grains of this composition in a spoon, and it will fly away with a fearful noise, like thunder. A grain by weight of this powder, put into a tobacco-pipe, will cause a loud report and much merriment, particularly if the smoaker is not aware of the trick put upon him.

_To set fire to a Combustible Body by the Reflection of two concave Mirrors._

The rays of a luminous body, placed in the focus of a concave mirror, being reflected in parallel lines, if a second mirror be placed diametrically opposite the first, it will, by collecting those rays in its focus, set fire to a combustible body.

Place two concave mirrors at about twelve or fifteen feet distance from each other, and let the axis of each of them lie in the same line. In the focus of one of them place a live coal, and in the focus of the other some gunpowder. With a pair of double bellows, which make a continual blast, keep constantly blowing the coal, and, notwithstanding the distance between them, the powder will presently take fire.

It is not necessary that these mirrors be of metal or glass; those made of wood or pasteboard, gilded, will produce the explosion, which has sometimes taken effect at the distance of fifty feet, when mirrors of eighteen inches or two feet diameter have been used.

_To give the Faces of the Company the Appearance of Death._

Dissolve some common salt in spirits of wine, and pour the whole on some saffron in a saucer. Take away the candle from the room, and set fire to the spirit with a little burning tow. The countenances of every person in the room will, by this light, put on a cadaverous, deadly appearance, the fairest complexion appearing green, whilst the red of the lips and cheeks will be of an olive hue.

_To dispose two little Figures, so that one shall light a Candle, and the other put it out._

Take two little figures of wood or clay, or any other materials you please, only taking care there is a little hole at the mouth of each. Put in the mouth of one a few grains of bruised gunpowder, and a little bit of phosphorus in the other, taking care that these preparations are made beforehand; then take a lighted wax candle, and present it to the mouth of the figure with the gunpowder, which, taking fire, will put the candle out; then present your candle, having the snuff quite hot, to the other figure; it will light again immediately by means of the phosphorus. You may propose the same effect to be produced by two figures, drawn on a wall with a pencil or a coal, by applying, with starch or a wafer, a few grains of bruised gunpowder to the mouth of one, and a bit of phosphorus to the mouth of the other.

_To construct a Lantern which will enable a Person to read by Night, at a great Distance._

Make a lantern of a cylindric form, or shaped like a small cask placed lengthways, so that its axis may be horizontal, and fix in one end of it a parabolic or spheric mirror, so that its focus may fall about the middle of the axis of the cylinder. If a small lamp or taper be placed in this focus, the light, passing through the other end, will be reflected to a great distance, and will be so bright, that very small letters on a remote object may be read, by looking at them with a good telescope. Those who see this light, if they be in the direction of the axis of the lantern, will think they see a large fire.

TRICKS WITH STRINGS, KNOTS, &c.

_To cut a Lace asunder in the Middle, and to make it whole again._

Provide a piece of the lace which you mean to cut, or at least a pattern like the same, one inch and a half long, and keep it double privately in your left hand, between some of your fingers, near to the tips thereof; take the other lace which you mean to cut, still hanging about your neck, and draw down your said left hand to the bout thereof, and, putting your own piece a little before the other, the end, or rather middle, whereof you must hide betwixt your fore-finger and thumb, make the eye or bout which shall be seen of your own pattern; let a bystander cut the same asunder, and it will be surely thought that the other lace is cut; which, with words and fretting, you shall seem to renew, and make whole again. This, if it be well handled, will seem very wonderful.

_To burn a Thread and make it Whole again with the Ashes._

Take two pieces of thread of one foot in length each: roll one of them round like a small pea, which put between your left fore-finger and thumb. Now, hold the other out at length, between the fore-finger and thumb of each hand, holding all your fore-fingers daintily; then let one cut the same asunder in the middle; when that is done, put the tops of your two thumbs together, and so shall you with less suspicion receive the thread which you hold in your right hand into your left, without opening your left finger and thumb. Then holding these two pieces as you did before it was cut, let these two be cut also asunder in the middle, and they conveyed again as before, until they be very short; then roll all these ends together, and keep that ball of thread before the other in the left hand, and, with a knife, thrust the same into a candle, where you may hold it until the said ball of thread be burnt to ashes; then pull back the knife with your right hand, and leave the ashes, with the other ball betwixt your fore-finger and thumb of your left hand, and, with the two thumbs and two fore-fingers together, take pains to rub the ashes till your thread be renewed, and draw out that thread at length, which you lay all this while betwixt your fore-finger and thumb. This is not inferior to any juggler’s trick, if it be well handled; for if you are so perfect in legerdemain as to bestow the same ball of thread, and to change it from place to place, betwixt your other fingers, as may be easily done, then it will seem very strange.

_To pull many Yards of Ribbon out of the Mouth._

Jugglers get money from maids, by selling laces by the yard, putting into their mouths one round bottom, as fast as they pull out another, and, at the exact end of every yard, they tie a knot, so as the same rests upon their teeth; then they cut off the same, and so the beholders are doubly and trebly deceived, seeing as much lace as will fill a hat, and the same of what colour they like, to be drawn out of the mouth; and yet the juggler talks as though there was nothing in his mouth.

_To cut a Piece of Tape into four Parts, and make it Whole again with Words._

Take a piece of narrow white tape, about two or three yards long. First present it to view to any that may desire it; then tie both the ends of it together, and take one side of it into one hand, so that the knot may be about the middle of one side, and, using some circumstantial words to beguile the spectators, turn one hand about toward yourself, and the other from you; so shall you twist the tape once, then clap the ends together, and then, if you slip your finger and thumb of each hand between the tape, almost as one would hold a skein of thread to be wound, this will make one fold or twist, as thus appears, where A signifieth the twist or fold--B the knot. Then

in like manner make a second fold, about the line D C, as you may see by the second figure, where B signifieth the knot, C the first fold, and A the second fold; then hold the fore-finger and thumb of your left hand upon the second twist, and upon the knot also, and the fore-finger and thumb of your right hand upon the first fold C, and desire some one of your spectators to cut all asunder with a sharp knife at the cross line E D; when it is cut, hold still your left hand, and let all the ends fall that you hold in your right hand, for there will be a show of eight ends, four above and four below, and so the strings will be thought to be cut into four parts, as may be seen by the third figure; then gather up the ends that you let fall into your left hand, and deliver two of the ends (seeming to take them at random) unto two several persons, bidding them hold them fast, still keeping your left-hand fingers upon the twists or folds; then with both your hands seem to tumble all the ends together that you had in your left hand, twist out the slips and pieces, which are three, as you may see at A and B in the third figure,--twist them all, I say, into a little ball, and conceal it between some of your fingers of your left hand, and crumble thereon another confused heap, and, after some words said, with your right hand deliver this confused heap unto any of the company, bidding them hold it fast, saying, “_Hulla passa_;” then bid them look on it, and while they are greedily looking after the event, you may with ease convey the ball or roll of ends into your pocket; so it will be thought that you have made it whole by virtue of your words. This is an excellent trick, if it be gracefully handled: it cost me a great deal of trouble and time to find it out.

_To unloose a Knot upon a Handkerchief by Words._

Make a plain loose knot with two ends of a handkerchief, seeming to draw the same very hard. Hold fast the body of the handkerchief near to the knot, with your right hand, pulling the contrary end with your left. Then close up handsomely the knot, which will be somewhat loose, and pull the handkerchief so with your right hand, that the left hand may be near the knot; then will it seem to be a true and firm knot; and to make it appear more assuredly to be so indeed, let a stranger pull at the end which you hold in your left hand, while you hold fast the other in your right hand, and then holding the knot with your fore-finger and thumb, and the lower part of your handkerchief with your other finger, as you hold a bridle when you would with one hand slip up the knot and lengthen the reins. This done, turn your handkerchief over the knot with your left hand; in doing whereof you must suddenly slip out the end or corner, putting up the knot of your handkerchief with your fore-finger and thumb, as you would put the aforesaid knot of your bridle. Then deliver the same, covered and wrapped within the midst of the handkerchief, to one to hold fast, and, after the pronunciation of some words of art, take the handkerchief and shake it, and it will be loose.

_To draw a Cord through the Nose._

This trick is called the bridle, being made of two alder sticks--

Through the hollowness thereof is placed a cord, the same being put upon the nose, like a pair of pincers or tongs; the cord which goeth round the same being drawn to and fro, the beholders will think the cord goes through your nose very dangerously; the knots at the end of the cord, which stay the same from being drawn out of the stick, must not be put at the very top, for that must be stopped up, but half an inch beneath each end; and so, when it is pulled, it will seem to pass through the nose. Then you may take a knife and seem to cut the cord asunder, and pull the bridle from your nose.

_To take three Button-Moulds off a String._

Take two little whipcords, of two feet long each, double them equally, so as there may appear four ends; then take three button-moulds (the hole of one of them must be bigger than the rest), and put one button-mould upon the eye or bout of one cord, and another on the other cord; then take the button-mould with the greatest hole, and let both the bouts be hidden therein, which may be the better done if you put the eye, or bout, of the one

into the eye or bout of the other; then put the middle button upon the same, being doubled over his fellow: so will the heads seem to be put over the two cords. You may loose them as you like, and make it seem manifest to the beholders, who may not see how they are done; but that the buttons are put upon the two cords, without any fraud. Then must you seem to add a more effectual binding of those buttons to the strings, and make one half of a knot with one of the ends of each side, which is for no other purpose, but that, when the buttons are taken away, the cords may be seen in the case which the beholders suppose to be in before; for when you have made your half knots, which in any wise you must not double to make a perfect knot, you must deliver into the hands of some bystanders these two cords--namely, two cords evenly set to one hand, and two in the other, and then with a wager begin to pull off the buttons, which, if you handle nimbly, and in the end cause him to pull his two ends, the two cords will show to be placed plainly, and the buttons to have come through the cords.

OPTICAL ILLUSIONS.

_The Multiplying Mirror._

A mirror is to be made as follows: first make a hoop or fillet of wood about the width of a half-crown piece, and let the thickness be about a quarter of an inch. In the middle of this hoop fasten a bottom of wood or brass, and place several hooks of the size of small peas. Then open the one side of this bottom, set in a piece of crystal glass, and fasten it in the hoop close to the bottom;

then take a quantity of quicksilver, and put so much into the hoop as will cover the bottom; then let into the hoop another piece of crystal glass fitted thereto, and cement the sides that the quicksilver may not run out, and it is done,--the use whereof I shall not insist upon, since he that is versed in optical illusions will better conceive it, than any words of mine can either direct or assist him.

_The Magic-Lantern._

This lantern is called magical on account of the formidable apparitions that, by virtue of light, show upon the white wall of a dark room. The body of it is generally made of tin, and of the shape of a lamp. Towards the back is a concave looking-glass of metal, which may either be spherical or parabolical, and which, by a grove made in the bottom of the lantern, may be either advanced nearer or put farther back from the lamp, in which is oil or spirit of wine; and the match ought to be a little thick, that when it is lighted it may cast a good light that may easily reflect from the glass to the fore part of the lantern, where there is an aperture with a prospective in it, composed of two glasses, that make the rays converge and magnify the object.

When you mean to make use of this admirable machine, light the lamp, the light of which will be much augmented by the looking-glass at a reasonable distance. Between the fore part of the lantern and the prospective glass you have a trough, made on purpose, in which you are to run along a flat frame, with transparent colours on glass. Then all these little figures, passing successively before the prospective glass, through which passes the light of the lamp, will be painted and represented with the same colours upon the wall of a dark room, and in a gigantic and monstrous manner.

By this lantern you may show birds, beasts, and all sorts of fish, &c. &c. &c.

_The Phantascope._

The Phantascope is a magic-lantern improved; that is, it will magnify or diminish the figures it is to reflect, without impairing their neatness.

This instrument is composed of a tin box, surmounted by a kind of chimney, pierced on one of its faces with a hole of a diameter corresponding with that of the cylinders, sliding into one another like the tubes of an opera-glass: this tube is adjusted by means of a slide established above the aperture made in the phantascope. The part of the adjoining cylinder is so adjusted to receive alternately wooden tablets, in which are opened cavities to contain the figures painted upon glass. The flat side of the half ball is placed in that tube, nearly close enough to touch the painted figures: this half ball is called the object glass.

In the second cylinder is found a magnifying-glass, convex on both sides, the focus whereof is double to that of the half ball, and one third of its diameter: this glass is called “the eye-glass.” It is by means of drawing those glasses close that the objects are magnified; and by removing them at a distance, that the figures are made to look smaller. Inside of the box is placed one of those lamps called “argand,” of a wide diameter, with a concave mirror, to throw as much light as possible upon the transparent figures.

To exhibit the phantasmagoria, select an apartment opening into a second room, and the door of which is at your disposal: take a wooden frame, exactly of the same dimensions as that door, upon which fasten, with brass nails, a sheet of fine linen, in preference to calico. A moment before you place the frame, wet it equally all over, to cause the thread of the cloth to swell, and to fill all interstices.

When you have proved the above-mentioned instrument, prior to your using it, make sure that the lamp does not smoke, but that it gives a vivid light; that the concave mirror is very bright; that the magnifying-glass is dry and clean. (You dry these with a piece of soft leather and some whitening, so fine as not to scratch. The painted glasses are cleaned with a piece of very fine cloth, made quite hot, or of cambric, taking care not to rub off the painting.) You then place the wooden ruler with the reversed figure in the slide, opened purposely to receive it, in the first cylinder; then, the figures being reflected on a whitewashed wall, you regulate the distance of the magnifying-glasses, in order to have the paintings seen in all their perfection at a regular fixed distance. Your instrument is then ready for the exhibition.

To this effect, you present yourself facing the framed linen, with the phantascope suspended before you, and held by two braces across your shoulders. In order that the figures may decrease in the eyes of the spectators of the other side, you must advance slowly near the cloth, drawing the two magnifying-glasses at a distance from each other, but very gently, that the figures should remain steady.

If, on the contrary, you should wish them to appear magnified, gradually draw back, with the same precaution, and bring the glasses nearer each other; when they are quite close, the figures seem to be coming towards the spectators, and to proceed forward.

When you change the paintings, you must hide the eye-glass behind an opaque and black body. The knowledge of the management of the glasses, and the accuracy of the proceeding backward and forward, upon which depends entirely the good effect of the exhibition, may be acquired by a few days’ practice previous to the exhibition being made in company.

Notwithstanding the box for the phantascope, if made of wood, will be heavier than a tin one, yet it is to be preferred, on account of its communicating much less heat than the tin.

Such persons as wish to paint their figures should use a varnish that does not spread on the glass; thick copal varnish will answer the purpose.

_The Enchanted Mirrors._

Make a box of wood, of a cubical figure, of about fifteen inches every way. Let it be fixed on a pedestal, at the usual height of a man’s head. In each side of this box, let there be an opening of an oval form, ten inches high, and seven wide.

In this box place two mirrors, with their backs against each other; let them cross the box in a diagonal line, and in a vertical position. Decorate the openings in the sides of this box with four oval frames, and transparent glasses, and cover each of them with a curtain, so contrived that they may all draw up together.

Place four persons in front of the four sides, and at equal distances from the box, and then draw up the curtains, that they may see themselves in the mirrors; when each of them, instead of his own figure, will see that of the person who is next him, and who, at the same time, will seem to him to be placed on the opposite side. Their confusion will be the greater, as it will be very difficult for them to discover the mirror contained in the box. The reason of this phenomenon is evident; for, though the rays of light may be turned aside by a mirror, yet they always appear to proceed in right lines.

_The Wonderful Phantoms._

In a partition make two apertures of a foot high, and ten inches wide, and about a foot distant from each other. Let them be at the common height of a man’s head; and in each of them place a transparent glass, surrounded with a frame, like a common mirror.

Behind this partition place two mirrors, inclined to it in an angle of forty-five degrees (that is, be halfway between a line drawn perpendicular to the ground and its surface); let them be both eighteen inches square; let all the space between them be enclosed by boards, or pasteboard, painted black, and well closed, that no light may enter. Let there be also two curtains to cover them, which may be drawn aside at pleasure.

When a person looks into one of these supposed mirrors, instead of seeing his own face, he will perceive the object that is in front of the other; so that, if two persons present themselves at the same time before these mirrors, instead of each one seeing himself, they will reciprocally see each other.

Note.--There should be a sconce, with a candle placed on each side of the two glasses in the wainscot, to enlighten the faces of the persons who look in them; otherwise this experiment will have no remarkable effect.

This curious trick may be considerably improved, by placing the two glasses in the partition in adjoining rooms; and, a number of persons being previously placed in one room, when a stranger enters the other, you may tell him his face is dirty, and desire him to look in the glass, which he will naturally do; and on seeing a strange face he will draw back; but, returning to it, and seeing another, and another, like the phantom kings in Macbeth, what his surprise will be is more easy to conceive than express. After this, a real mirror may be privately let down on the back of the glass, and, if he can be prevailed to look in once more, he will then, to his further astonishment, see his own face, and may be told, perhaps persuaded, that all he thought he saw before was mere imagination.

How many tricks, less artful than this, have passed in former times for sorcery, and pass at this time, in some countries, for apparitions!

Note.--When a man looks in a mirror that is placed perpendicular to another, his face will appear entirely deformed. If the mirror be a little inclined, so as to make an angle of eighty degrees (that is, one ninth part from the perpendicular), he will then see all the parts of his face, except the nose and forehead. If it be inclined to sixty degrees (that is, one third part), he will appear with three noses and six eyes: in short, the apparent deformity will vary at each degree of inclination; and when the glass comes to forty-five degrees (that is, half way down), the face will vanish. If, instead of placing the two mirrors in this situation, they are so disposed that their junction may be vertical, their different inclinations will produce other effects, as the situation of the object relative to these mirrors is quite different.

_The Real Apparition._

Behind a partition place, in a position somewhat oblique, a concave mirror, which must be at least ten inches in diameter, and its distance from the partition equal to three fourths of the distance of its centre.

In the partition, make an opening of seven or eight inches, either square or circular: it must face the mirror, and be of the same height with it. Behind this partition place a strong light, so disposed, that it may not be seen at the opening, and may illumine an object placed near it, without throwing any light on the mirror.

Beneath the aperture in the partition, place an object that you intend shall appear on the outside of the partition, in an inverted position, and which we will suppose to be a flower. Before the partition, and beneath the aperture, place a little flower-pot, the top of which should be even with the bottom of the aperture, that the eye may see the flower in the same position as if its stalks came out of the pot.

Take care to paint the space between the back part of the partition and the mirror black, to prevent any reflections of light from being thrown on the mirror; in a word, so dispose the whole that it may be as little enlightened as possible.

When a person is placed at the point of vision, he will perceive the flower that is behind the partition, at the top of the pot; but, on putting out his hand to pluck it, he will find that he attempts to grasp a shadow.

_Observations._

The phenomena that may be produced by means of concave mirrors are highly curious and astonishing. By their aid spectres of various kinds may be exhibited. Suppose, for example, you were to tell any one, that at such an hour, and in such a place, he should see the apparition of an absent or deceased friend (of whose portrait you are in possession); in order to produce this phantom, instead of the hole in the partition, there must be a door which opens into an apartment to which there is a considerable descent. Under that door you are to place the portrait, which must be inverted and strongly illuminated, that it may be properly reflected by the mirror, which must be large and well polished. Then, having introduced the spectator at another door, and placed him in the proper point of view, you suddenly throw open the first door, when, to his great astonishment, he will immediately see the apparition of his friend.

It will be objected, perhaps, that this is not a perfect apparition, because it is only visible at one point of view, and by one person. But it should be remembered, that it was an established maxim in the last century, that a spectre might be visible to one person, and not to others. So Shakespeare makes both Hamlet and Macbeth see apparitions that were not visible to others, present at the same time. It is not unlikely, moreover, that this maxim took its rise from certain apparitions of the kind, _that were raised by the monks, to serve some purposes they called religious_; as they alone were in possession of what little learning there then was in the world.

_To draw a Deformed Figure, which will appear well proportioned from a certain Point of View._

Draw any thing you may fancy on a thin white pasteboard; then prick it; afterwards put the same on an horizontal surface, which we will suppose to be another pasteboard; put a lighted candle behind that drawing, and draw on the horizontal surface the lines given by the light; this will give a deformed design. This being done, take away the drawing that was pricked, and the candle; then place your eye where the light was, and you will see your drawing assume a regular form.

CHEMICAL CHANGES.

_To change the Colour of a Rose._

Burn some sulphur under the rose, by holding underneath it a lighted bundle of matches. This will fade the red colour, and make the flower turn white or blanched. Its primitive colour will return in about a couple of hours.

_To turn Water into Wine._

Take four glasses; rub one in the inside with a piece of moist alum: let the second have a drop of vinegar in it; the third empty. Let the fourth be filled with clean water; in your mouth put a clean rag, with ground basil tied close in it, the bulk not to be bigger than a small nut, which must lie between your hind teeth and your cheek; then take some of the water that is in the glass into your mouth, and return it into the glass that hath the drop of vinegar in it, which will cause it to turn the perfect colour of sack wine; then turn it in your mouth again, and chew the rag of basil between your teeth, and squirt the liquor into the glass, and it will have the perfect colour of claret; returning the basil into its former place, take the liquor into your mouth again, and presently squirt it into the glass you rubbed with alum, and it will have the perfect colour of mulberry wine.

_Arbor Dianæ; or, the Silver Tree._

This name has been given to a beautiful and curious precipitation of silver, by means of mercury in an arborescent form. The experiment is made by putting a soft amalgam of silver into six parts of a solution of nitrate of silver, and four of a solution of nitrate of mercury, or--

Amalgamate in a glass mortar one quarter of an ounce of pure mercury and half an ounce of fine silver. Insert in this amalgamation four ounces of pure nitric acid for the solution, and increase the whole by a pint of distilled water; mix it well, and keep it in a glass decanter well stopped. By introducing into this liquid a lump of soft amalgam of silver, the formation of the tree speedily takes place.

Or, if you wish to make the experiment on a smaller scale, pour about an ounce of the above liquid into a wine-glass, into which insert a piece of soft amalgam of silver, the size of a pea, and the effect required will immediately be produced. The silver, separating in the form of prismatic needles, will arrange itself so as to assume an arborescent appearance.

_The Lead Tree._

The precipitation of a solution of acetate of lead by means of a piece of zinc, so as to form what is commonly called the lead tree, is perfectly analogous to this theory, but is too well known to require illustration.

_The Tree of Mars._

Dissolve iron filings in aqua fortis moderately concentrated, till the acid is saturated; then pour gradually into the solution a solution of fixed alkali, commonly called oil of tartar. A strong effervescence will take place, and the iron, instead of falling to the bottom of the vessel, will afterwards rise, so as to cover its sides, forming a multitude of ramifications heaped one upon the other, which will sometimes pass over the edge of the vessel, and extend themselves on the outside, with all the appearance of a plant. If any of the liquor is spilt, it must be carefully collected, and be again put into the vessel, where it will form new ramifications, which will contribute to increase the mass of the vegetation.

_To form a Metallic Tree, in the Shape of a Fir._

In a small globular bottle with a tall neck, dissolve one ounce of fine silver in three ounces of nitric acid; put the bottle into a sand bath, and let it remain over a slow fire till the liquid be half reduced; then add three ounces of good white-wine vinegar, a little warmed; shake the mixture, and place the bottle in any place where it is not likely to be disturbed: in about a month’s time a beautiful metallic fir will appear, ramifying to the very surface of the liquid.

_To make a Gold or Silver Tree, to serve as a Chimney Ornament._

Make an amalgam of a small portion of fine gold, and ten times the quantity of purified cinnabar.

Grind and wash the amalgam in water, till no black colour appears: when perfectly clean, dry the amalgam, and insert it into a glass retort; place it in a sand bath over a slow fire, which must be preserved ignited for a day or two; gradually increase the heat, to expel the mercury from the gold, whose metallic vegetation will be perfectly in proportion to the mercury which escapes. When the fire is extinguished you will find the mercury expelled into the receiver, and the gold remaining in the retort will be soft and malleable, possessing the purest appearance; the mass will have sprouted branches, in perfect imitation of small shrubs and trees of different forms and height, which may be separated from the heap, serving as their base, when taken from the retort. These will allow even of being made red hot without injury to their appearance, or fear of decomposition, and may be used as ornaments for any length of time.

For the silver, use the same proportion of metal as for the gold tree.

_Sympathetic or Secret Inks._

Sympathetic or secret inks are those fluids which, when written with on paper, are invisible when dry, but acquire colour by heating the paper, or by applying to the invisible writing another chymical agent. These phenomena arrested particularly the attention of the old chymists, and accordingly, in their fanciful way, they called them _sympathetic inks_.

The writing made with this ink may, therefore, at pleasure be made to become visible or invisible successively, by alternately warming and cooling, if care be taken not to expose the paper to a greater degree of heat than is necessary to make the invisible writing legible.

_Preparation of Green Sympathetic Ink._

Put into a mattrass one part of cobalt or zaffree, and four ounces of nitro-muriatic acid. Digest the mixture with a gentle heat until the acid dissolves no more; then add muriatic of soda, equal in quantity to the cobalt employed, and four times as much water as acid, and filter the liquor through paper.

_Blue Sympathetic Ink._

This ink, which may be used like the preceding, is prepared in the following manner. Take one ounce of cobalt reduced to powder, put it into a Florence flask, and pour over it two ounces of pure nitric acid. Expose the mixture to a gentle heat, and, when the cobalt is dissolved, add, by small quantities, a solution of potash, until no more precipitate ensues. Let these precipitates subside: decant the super-natant fluid, and wash the residuum repeatedly in distilled water, until it passes tasteless; then dissolve it in a sufficient quantity of distilled vinegar, by the assistance of a gentle heat, taking care to have a saturated solution, which will be known by part of the precipitate remaining undissolved after the vinegar has been digested on it for some time.

_Yellow Sympathetic Ink._

Neutralize muriatic acid with brown oxide of copper: the solution is of a dark olive-green colour, and by evaporation yields crystals of a grass-green colour of muriate of copper, which, when dissolved in ten parts of water, forms this ink, and may be employed as before stated.

_Purple Sympathetic Ink._

Dissolve cobalt or zaffre in nitric acid, add salt of tartar gradually and in small quantities to avoid too powerful an effervescence, let the precipitate subside, and, having drawn off the super-natant clear liquid, add a sufficient quantity of water, when the ink will be fit for use.

_Rose-coloured Sympathetic Ink._

Dissolve zaffre in nitric acid, to which add saltpetre well purified, and you will possess a rose-coloured ink, having the same properties as the preceding.

_Application of the Secret Inks._

Write any unimportant matter with common ink, and let the lines be tolerably wide apart; then between these lines write the communication you wish to make with any of the above invisible inks. Your correspondent, by holding the paper before the fire, will be speedily enabled to peruse the letter; the characters will again become invisible when the paper has cooled. The writing in common ink will serve to lull the suspicions of those who might intercept the letter.

With this kind of ink, some very ingenious and amusing tricks may be performed.

_A Drawing which alternately represents Winter and Summer Scenes._

Draw a landscape, and delineate the ground, the trunks, and branches of the trees, with the usual water-colours employed for that purpose, tracing the grass and trees with sympathetic ink. By these means you will have a drawing, which, at the common temperature of the atmosphere, will represent a winter piece; but if it be exposed to a proper degree of heat, not too strong, you will see the ground covered with verdure, and the trees suddenly wrapped with a beautiful foliage; replace the picture in the cool, and the dreary aspect of winter re-appears. The colours must be lighter for the back grounds.

Screens painted in this manner were formerly made at Paris. Those to whom they were presented, if unacquainted with the artifice, were astonished to find, when they made use of them, that the views they exhibited were totally changed. Persons not understanding drawing may amuse themselves in this manner, by colouring an outlined engraving representing winter, following exactly the process enjoined for the above.

_Demonstration of the various Strata of Earth which cover the Globe._

In a middling-sized glass bottle, three parts full of clear water, infuse pure alumine precipitated by ammonia, till the bottle is nearly filled.--Expose the bottle to the cold air in frosty weather; or, at other times, to artificial frost. At the moment when the frigorific effect ensues, the alumine will divide all over the surface of the water, and form itself into separate and very regular strata.

_To freeze Water in the Midst of Summer, without the Application of Ice._

Take eleven drachms of muriate of ammonia, ten of nitrate of potash, and sixteen of sulphate of soda; reduce each of these salts separately to a fine powder, and mix them gradually in a glass, or rather in a thin metal vessel, with five ounces of water (the capacity of the vessel should be only just large enough to hold the materials): the result will be, that, as the salts dissolve, cold will be produced, and a thermometer immersed in the mixture will sink at or below freezing. A little water, about half an ounce, in a test tube, when immersed in the mixture during its solution, becomes frozen in about ten minutes.

The salts employed in this experiment may be recovered from the solution, if the sulphate of soda be omitted, by evaporating the water, to serve again any number of times. Five parts of muriate of ammonia, five of nitre, and eight of sulphate of soda, mixed with sixteen of water, at the usual temperature, sink the thermometer from 50 to about 10 degrees.

The salts, to produce their fullest frigorific effect, should be recently crystallized in fine powder, and contain as much water of crystallization as possible, but they should not be damp.

If to three parts of ice thus procured, you add four parts of potash, the thermometer will sink from 32° to 61° below Zero, or the freezing point; giving 93 degrees of cold. Snow or common ice, mixed with potash in the same proportions, would serve equally well; but the above experiments are given under the supposition that they are difficult to be procured.

MISCELLANEOUS TRICKS AND EXPERIMENTS.

_To swallow a long Pudding made of Tin._

This pudding must be made of tin, consisting of twelve or thirteen little hoops, round, and in little ringlets, so that they may seem to fall one through another. It must have little holes made at the biggest end, that it may not hurt your mouth: hold this pudding, for so it is called, privately in your left hand, with the hole end uppermost, and with your right hand take a ball out of your pocket, and say, “_If there is any old woman that is out of conceit with herself, because her neighbours deem her not so young as she would be thought, let her come to me, for this ball is a present remedy_;” then seem to put the ball into your left hand, but let it slip into your lap, and clap the pudding into your mouth, which will be thought to be the ball that you showed them; then decline your head, and open your mouth, and the pudding will slip down at its full length, which, with your right hand, you may strike into your mouth again; doing this three or four times: then you may discharge it into your hand, and clap it into your pocket without any suspicion, by making three or four wry faces after it, as though it had stuck in your throat; and if you practise smiting easily on your throat, with your fist on each side, the pudding will seem to chink as if it was laying there; then say, “_Thus they eat puddings in High Germany; they fling them down their throats before their teeth can take possession of them._”

_An Artificial Spider._

Take a bit of burnt cork, as big as a pea, and give it the shape of a spider; make its legs with threads of hemp; put a grain of lead into the cork to give it some weight; then hang this artificial spider by a bit of gray sewing silk (that is not twisted), between two bodies, the one electrified, and the other not; or between two bodies endowed with different electricities: it will go and come between these two bodies, and the movement of the legs will be seen as plainly as if it were a living spider.

_To pass a Ring through your Cheek._

You must have two rings made of silver or brass, or what you please, of one size, colour, and likeness, saving that one must have a notch through it, and the other must be whole, without a notch; show the whole ring, but conceal that which hath the notch, and say, “_Now I’ll put this ring through my cheek_,” and privately slip the notch over one side of your mouth; then take a small stick, which you must have in readiness, and slip the whole ring upon it, holding your hand over it about the middle of the stick; then bid somebody hold fast the stick at both ends, and say, “_See this ring in my cheek,--it turns round_;” then, while you perceive them fasten their eyes upon that ring, on a sudden, whip it out, and smite upon the stick therewith; instantly concealing and whirling the other ring you hold your hand over, round about the stick. It will be thought that you have brought that ring upon the stick which was upon your cheek.

_To cut a Hole in a Cloak, Scarf, or Handkerchief, and by Words to make it whole again._

To do this, you must have a piece of the same ready in your hand, the sample of that you intend to cut; then, amongst other tricks, clap your hand upon the place you intend to cut. Now drawing the false piece through, cause it to be cut off, and, griping your hand, show the hole from whence the piece came away which is in your hand. This is done by pretending to feel in your pocket for a needle and thread to sew it up again. But, drawing your hand out of your pocket, say “_I have no needle, but I have a charm that will do as well_;” so, muttering some words, bid them blow upon it, and, pulling your hand from the place, show it entire.

_The Dancing Egg._

Three eggs are brought out; two of them are put on a table, and the third in a hat; a little cane is borrowed from one of the company, and it is shown about, to convince the spectators there is no preparation. It is then placed across the hat; the hat falls to the ground, and the egg sticks to it as if glued; the orchestra then plays a piece of music, and the egg, as if it was sensible of the harmony, twists about the cane from one end to the other, and continues its motions till the music stops.

_Explanation._--The egg is fastened to a thread by a pin, which is put in lengthways; and the hole, which has been made to introduce this pin, is stopped with white wax. The other end of the thread is fastened to the breast of the person who performs this trick, with a pin bent like a hook; the cane, passing under the thread, near to the egg, serves for it to rest on. When the music begins, the performer pushes the cane from left to right, or from right to left; it then appears as if the egg ran along the cane, which it does not, being fastened to its thread; its centre of gravity remains always at the same distance from the hook that holds it; it is the cane which, sliding along, presents its different points to the surface of the egg.

N. B. To produce the illusion, and persuade the company that it is the egg which carries itself to the different points of the cane, the performer turns a little on his heel; by this means the egg receives a motion, which surprises the spectators, it remaining always at the same distance from the point to which it was fastened.

_To make Three Figures dance in a Glass._

Take little hollow figures of glass about an inch and a half high, representing little children, or grown-up persons. These may be had of the glass-blowers; and, as they contain a body of air, are lighter than water. Immerse them in water contained in a glass of the following shape:--

This glass is about a foot or fifteen inches high, and covered with a bladder, which is tied fast over the top; a small quantity of air is to be left between the bladder and surface of the water; so, when you command them to walk down, press your hand hard upon the top, and they will immediately go down. Thus you may make them dance in the middle of the glass, at your pleasure; and, when you would have them go up to the top, take your hand away, when they will go up.

_To shoot a Swallow, and to bring him to Life again._

Load your gun with the usual charge of powder, but, instead of shot, put in half a charge of quicksilver: prime and shoot. If your piece bears ever so far from the bird, the swallow will find itself stunned to such a degree, as to fall to the ground in a fit. As it will regain its senses in a few minutes, you may make use of the time, by saying that you are going to bring it to life again. This will greatly astonish the company. The ladies will, no doubt, interest themselves in favour of the bird, and intercede for its liberty;--sympathizing with their feelings for the little prisoner may be the means of some of them sympathizing with yours.

_Singular Trick with a Fowl._

Take a cock from roost at night, or off its walk by day, and bring him into a room full of company; keep both your hands close to his wings; hold them tight: put him on a table, and point his beak down as straight as possible; and then let any one draw a line with a piece of chalk, directly from his beak, and all the noise you can possibly make, with drums, trumpets, or even crowing of other cocks, will not disturb him from the seeming lethargy, which that position you have laid him in, with the chalked line, has effected. Strange as this seems, yet the certainty of it is past a doubt, as many gentlemen who have, ere this, sported some hundreds on the turf, are ready to assert its truth.

_To put a Lock upon a Man’s Mouth._

You must have a lock made for this purpose, according to the figure; one side of its bow must be immoveable, as that marked A; the other side is noted B, and must be pinned to the body of the lock, as appears at E.

It must be so pinned that it may play to and fro with ease; this side of the bow must have a leg as at B, and then turn it into the lock; this leg must have two notches filed on the inner side, which must be so managed that one may lock or hold the two sides of the bow as close together as possible, and the other notch to hold the said part of the bow a proportionable distance asunder: so that, being locked upon the cheek, it may neither pinch too hard, nor yet hold it so slight that it may be drawn off. Let there be a key fixed to it to unlock it, as you see at D; and, lastly, let the bow have divers notches filed in it, so that the place of the partition, when the lock is shut home, will the least of all be suspected in the use of the lock. You must now get one to hold a sixpence, edgeways, between his teeth; then take another sixpence, and with your left hand proffer to set it edgeways between a second man’s teeth, pretending that your intent is to turn both into which of their mouths they shall desire, by virtue of your words; which he shall no sooner consent to do, but you, by holding the lock privately in your right hand, with your fore-finger a little down, after certain words, and the lock having hung on a while, may seem to pull the key out of his nose.

_To thrust a Bodkin into the Forehead, without Hurt._

Take a hollow bodkin, so that the blade may slip therein as soon as the point is held upwards. Seem to thrust it into your forehead, and, with a little sponge in your hand, bring out blood or wine, making the spectators think that the blood or wine (whereof you may say you have drank very much) runs out of your forehead; then, after showing some appearance of pain, pull away your hand suddenly, holding the point downwards, and it will fall out, and seem never to have been thrust into the haft; but, immediately afterwards, throw that bodkin into your lap or pocket, and pull out another plain one like it, which will completely deceive the spectators.

_To thrust a Bodkin through your Tongue._

This trick is to be performed in much the same manner as the former, and, as in the first case, without hurt; if the reader will take the pains to practise this trick, he will be in no more danger of performing one than the other.

To render the deception as complete as possible, proceed as follows:--Make a bodkin, or nail, the blade thereof being cut in the middle, so that one part may not be close to the other, by almost three quarters of an inch, each part being kept asunder by a small crooked piece of iron, of the fashion described in the next trick; then thrust your tongue between the aforesaid place, to wit, into the space left in the bodkin-blade, thrusting the said part behind your teeth, and biting it. It will seem to stick so fast in, and through your tongue, that one can hardly pull it out. You must have another bodkin or nail, just like the false one, to show the company.