On the six-sided plane A B C D E F of the figure, draw six semi-diameters; and on each of these place perpendicularly two plane mirrors, which must join exactly at the center, and which, placed back to back, must be thin as possible. Decorate the exterior boundary of this piece, (which is at the extremity of the angles of the hexagon,) with six columns, that at the same time serve to support the mirrors by grooves formed on their inner sides. Add to these columns their entablatures, and cover the edifice in whatever manner you please. In each one of these six triangular spaces, contained between two mirrors, place little figures of pasteboard, in relief, representing such subjects, as when seen in an hexagonal form, will produce an agreeable effect. To these add small figures of enamel, and take particular care to conceal by some object that has no relation to the subject, the place where the mirrors join, which, as before observed, all meet in the common center.

When you look into any one of the six openings of this palace, the objects there contained, being reflected six times, will seem entirely to fill up the whole of the building. This illusion will appear very remarkable, especially if the objects chosen are properly adapted to the effect which the mirrors are intended to produce.

If you place between two of these mirrors part of a fortification, as a curtain, and two demi-bastions, you will see an entire citadel with six bastions; or if you place part of a ball-room, ornamented with chandeliers and figures, all these objects being here multiplied, will afford a very pleasing prospect.

TO KNOW WHICH OF TWO DIFFERENT WATERS IS THE LIGHTEST WITHOUT ANY SCALES.

Take a solid body, the specific gravity of which is less than that of water, pine, or fir wood, for instance, and put it into each of the two waters, and rest assured that it will sink deeper in the lighter than in the heavier water; and so by observing the difference of the sinking, you will know which is the lightest water, and consequently the most wholesome for drinking.

TO KNOW IF A SUSPICIOUS PIECE OF MONEY IS GOOD OR BAD.

If it be a piece of silver that is not very thick, as a dollar or a half dollar, the goodness of which you want to try, take another piece of good silver of equal balance with it, and tie both pieces with thread or horse-hair to the scales of an exact balance (to avoid the wetting of the scales themselves) and dip the two pieces thus tied in water; for then, if they are of equal goodness, that is, of equal purity, they will hang in equilibrio in the water as well as in the air; but if the piece in question is lighter in the water than the other, it is certainly false, that is, there is some other metal mixed with it that has less specific gravity than silver, such as copper. If it is heavier than the other, it is likewise bad, as being mixed with a metal of greater specific gravity than silver, such as lead.

If the piece proposed is very thick, such as that crown of gold that Hiero, king of Syracuse, sent to Archimedes to know if the goldsmith had put into it all the eighteen pounds of gold that he had given him for that end, take a piece of pure gold of equal weight with the crown proposed, viz., eighteen pounds, and without taking the trouble of weighing them in water, put them into a vessel full of water, one after another, and that which drives out most water must necessarily be mixed with another metal of less specific gravity than gold, as taking up more space, though of equal weight.

PYRAMID OF ALUM.

Put a lump of alum into a tumbler of water, and as the alum dissolves it will assume the shape of a pyramid. The cause of the alum decreasing in this peculiar form is briefly as follows: at first, the water dissolves the alum very fast, but as the alum becomes united with the water, the solvent power of the latter diminishes. The water, which combines first with the alum, becomes heavier by the union, and falls to the bottom of the glass, where it ceases to dissolve any more, although the water which it has displaced from the bottom has risen to the top of the glass, and is there acting upon the alum. When the solution has nearly terminated, if you closely examine the lump, you will find it covered with geometrical figures, cut out, as it were, in relief upon the mass; showing, not only that the cohesion of the atoms of the alum resists the power of solution in the water, but that, in the present instance, it resists it more in some directions than in others. Indeed, this experiment beautifully illustrates the opposite action of cohesion and solution.

THE DANCING AUTOMATON.

Procure a piece of silk thread about six feet long, and fasten a small wire hook at one end, and a fine needle at the other, then make a knot in the thread about ten inches from the end upon which the hook is fastened. You also procure a small pasteboard figure about four inches long, and pierce a hole through the center of the same just large enough to easily admit the needle. Having done this, take a convenient opportunity and fasten the hook in the carpet about five and a half feet from the chair upon which you intend to sit while performing the trick. You then can inform your audience that you intend to make the figure dance and keep time to any tune they may name. You then slip the needle through the hole in the figure and throw it down on the floor, with sufficient force to make it slip on the thread until it reaches the knot, being careful to retain the needle still in your hand, then whistle any air the company may suggest, and appear to beat time with your hands upon your knees. This will make the figure dance, to the great astonishment of the spectators. After you have continued this for a few minutes, you must drop the needle and pick up the figure, when the needle will again slide through the hole in the figure, and the automaton being free from the thread, you can hand it to the audience for examination. This is an excellent trick for the parlor, and, if well performed, will defy detection.

TO MELT A PIECE OF MONEY IN A WALNUT SHELL, WITHOUT INJURING THE SHELL.

Bend any thin coin, and put it into half a walnut shell; place the shell on a little sand, to keep it steady. Then fill the shell with a mixture made of three parts of very dry pounded niter, one part of flowers of sulphur, and a little sawdust well sifted. If you then set light to the mixture, you will find, when it is melted, that the metal will also be melted at the bottom of the shell, in form of a button, which will become hard when the burning matter round it is consumed: the shell will have sustained very little injury.

THE INVISIBLE SPRINGS.

Take two pieces of white cotton cord, precisely alike in length; double each of them separately, so that their ends meet; then tie them together very neatly, with a bit of fine cotton thread, at the part where they double (i. e. the middle). This must all be done beforehand. When you are going to exhibit the trick, hand round two other pieces of cord, exactly similar in length and appearance to those which you have prepared, but not tied, and desire your company to examine them. You then return to your table, placing these cords at the edge, so that they fall (apparently accidentally) to the ground, behind the table; stoop to pick them up, but take up the prepared ones instead, which you had previously placed there, and lay them on the table. You then take round for examination three ivory rings; those given to children when teething, and which may be had at any of the toyshops, are the best for your purpose. When the rings have undergone a sufficient scrutiny, pass the prepared double cords through them, and give the two ends of one cord to one person to hold, and the two ends of the other to another. Do not let them pull hard, or the thread will break, and your trick be discovered. Request the two persons to approach each other, and desire each to give you one end of the cord which he holds, leaving to him the choice.

You then say that, to make all fast, you will tie these two ends together, which you do, bringing the knot down so as to touch the rings; and returning to each person the end of the cord next to him, you state that this trick is performed by the rule of contrary, and that when you desire them to pull hard, they are to slacken, and vice versa, which is likely to create much laughter, as they are certain to make many mistakes at first. During this time you are holding the rings on the fore fingers of each hand, and with the other fingers preventing your assistants from separating the cords prematurely, during their mistakes; you at length desire them, in a loud voice, to slack, when they will pull hard, which will break the thread, the rings remaining in your hands, whilst the strings will remain unbroken: let them be again examined, and desire them to look for the springs in the rings.

THE FLIGHT OF THE RING.

You may cause a ring to shift from one hand to another and make it go on any finger required on the other hand, while somebody holds both your arms, in order to prevent communication between them, by attending to these instructions: Desire some lady in company to lend you a gold ring, recommending her at the same time to make a mark on it, that she may know it again. Have a gold ring of your own. which fasten by a small piece of catgut string to a watch barrel, and sew it to the left sleeve of your coat. Take the ring that is given you in your right hand; then putting, with dexterity, the other ring fastened to the watch-barrel near the entrance of your sleeve, draw it privately to the fingers' ends of your left hand. During this operation, hide the ring that has been lent you between the fingers of your right hand, and fasten it dexterously on a little hook sewed for the purpose, on your waistcoat, and hidden by your coat. After that, show your ring, which hold in your left hand; then ask the company on which finger of the other hand they wish it to pass. During this interval, and as soon as the answer has been given, put the before mentioned finger on the little hook, in order to slip the ring on it: at that moment let go the other ring, by opening your fingers. The spring which is in the watch-barrel, being confined no longer, will contract, and make the ring slip under the sleeve, without any body perceiving it, not even those who hold your arms, as their attention will be occupied to prevent your hands from communicating. After this operation, show the assembly that the ring is come on the other hand, and make them remark that it is the same that had been lent to you, or that the mark is right. Much dexterity is required in this trick, so that the deception may not be suspected.

MUSICAL FIGURES RESULTING FROM SOUND.

Cover the mouth of a wine glass, having a foot-stalk, with a thin sheet of membrane, over which scatter a layer of fine sand. The vibrations excited in the air by the sound of a musical instrument, held within a few inches of the membrane, will cause the sand on its surface to form regular lines and figures with astonishing celerity, which vary with the sound produced.

TO MAKE A CARD JUMP OUT OF THE PACK.

Let any person draw a card, and afterwards put it into the pack, but take care that you know where to find it at pleasure. This you may do by having forced it. Then put a piece of wax under the thumb-nail of your right hand, and fasten a hair by it to your thumb, and the other end of the hair, by the same means, to the card chosen: spread the pack upon the table, and, making use of any words you think fit, make it jump from the pack about the table.

THE TELL-TALE CARDS.

Tell any one to shuffle the pack, to take off the upper card, and to notice it, then to lay it on the table, with its face downward, and put so many cards upon it as will make up thirteen with the number of spots on the noted card.

For instance: if the card which the person first looked at was a king, queen, knave, or ten, bid him lay that card with its face downward, calling it ten; upon that let him lay another, calling it eleven; upon that, another, calling it twelve; and upon that, another, calling it thirteen; then bid him take off the next uppermost card: suppose it to be an eight, let him lay it down on another part of the table, calling it eight; upon the latter another, calling it nine, and so on in the same way, until he makes that heap up to thirteen; then let him go to the next uppermost card, and so proceed to lay out the third parcel in the same way as the two preceding, and should the uppermost card be an ace, he must lay it down, calling it one, the next two, &c.

All this should be done either while you are out of the room, or your back is turned; upon your turning round, you take the cards which have been left; your object being to count, without its being perceived, how many there are remaining, you throw aside the three top cards, and lay the next three on the table, with their faces upward; then throw away one, then turn up one, and so on in the same way, until you ascertain how many cards they are; we will suppose that you find twenty-five cards left; deduct ten, when the remaining fifteen will be the number of all the spots contained in all the bottom cards of the three heaps, counting the court cards as ten; you must recollect that ten is, in all cases, the number to be deducted from the cards remaining. Having found that fifteen is the number of spots on the cards, do not declare it at once; but select from those cards which lie on the table, face uppermost, three or four which added together will make fifteen.

For instance: should there be a deuce, a five, and an eight, lay them aside for a moment, and taking the other cards from which you selected the three, put them along with those which you previously rejected; you now hand the three telltale cards to any person, assuring him that the number of pips on those cards will be the same as those on the bottom cards of the three heaps, which will be found to be the case.

THE DOUBLE DOZEN.

Present a pack of cards to one of the company, desiring him to shuffle them well, and to get them shuffled by whomsoever he pleases; then make several persons cut them; after which you will propose to one of the company to take the pack and think of a card, and remember it, and likewise its order in the pack, by counting one, two, three, four, &c., till he comes, exclusively, to the one thought of; offer to go into another room, or to be blindfolded, while he is doing this. Now declare in what order the card shall be in the pack; say, for instance the twenty-fourth; and, by attending to the following instructions, it will prove to be so:—Suppose the person who thinks of the card stops at thirteen, and that the thirteenth card was the queen of hearts, the number you have stated it shall be in the pack being twenty-four; you return to the room, in case you had left it, or desire the handkerchief to be removed, if you have been blindfolded; and, without asking any question of the person who has thought of the card, ask only for the pack, and apply it to your nose, as if to smell it; then passing it behind your back, or under the table, take, from the bottom of the pack, twenty-three cards; that is to say, one less than the number you have stated the card thought of shall be; place these twenty-three cards on the top. This being done, return the pack to the person who had thought of the card, requesting him to reckon the cards from the top of the pack, beginning by the number of the card he thought of. His card being the thirteenth, he will be compelled to count fourteen, and you are to stop him when he comes to twenty-three, reminding him that the number you have mentioned is twenty-four, and that, consequently, the twenty-fourth card, which he is going to take up, will be the card thought of; and so it will most certainly be.[15]

THE HOUSEBREAKERS.

Take a pack of cards, and place all the aces together, the twos, the threes, and so on up to the kings. There will then be thirteen different heaps. You say, "Here are four houses (laying down the four aces separately), which four knaves enter for the purpose of robbing (laying a knave upon each ace), and take with them their implements for housebreaking (and upon each of the knaves you lay a two, three, four, five, six, seven, and eight). The mistresses of the houses come home (laying a queen upon each of the heaps), bringing their money with them (laying a nine upon each queen). Shortly after, their husbands also return (laying a king upon each queen), also bringing money with them" (laying a ten upon each heap). You have now disposed of all the cards, which form four distinct heaps. Then lay one heap over the other, and let as many persons cut them as please. When this is done, if you commence at the top of the pack, and lay the cards face downwards, one by one, so as to make thirteen separate heaps, you will find all the aces together, the twos, and so on, as you originally placed them.

THE MAGIC BOOK.

Provide an octavo book of plain paper, of whatever thickness you please. Turn over seven leaves from the beginning, and paint a group of flowers; then turn over seven more leaves, and paint the same again, and so on, until you have turned the book through to the end. Then paste a slip of paper or parchment to each of the painted leaves. Turn the book over again, and paint upon every sixth leaf a parrot, and then paste strips upon them as you did upon the first, only a little lower down. Proceed in this manner until you have painted the book full of pictures of various sorts, taking care one side of the leaves is left white paper. When you use the book, hold it in your left hand, and set the thumb of your right hand upon the first of the parchment stays; run the book through, and it will appear full of flowers; then stop and, blowing upon the book, run it through again, with the thumb upon the second slips of parchment, and it will, appear full of parrots. Afterwards, reverse the book, and run it through as before, and it will appear composed of blank paper.

THE TAPE TRICK.

This trick consists in suffering a person to tie your thumbs together tightly, and yet that you shall be able to release them in a moment, and tie them together again. The mode of performing this trick is as follows:—Lay a piece of tape across the palms of your hands, placed side by side, letting the ends hang down; then bring your palms quickly together, at the same time privately catching hold of the middle of the tape with your fourth and fifth fingers. Then direct any person to tie your thumbs together as tight as he pleases, but he will not, of course, in reality be tying them, because you have hold of the tape, yet it will nevertheless appear to him that he is doing so. Request him to place a hat over your hands; then blow upon the hat, and say, "Be loose," slipping your thumbs from under the tape; direct him to remove the hat, and show your thumbs free. You then request the hat may again be placed over your hands, and blowing upon it, you say "Be tied," slipping your thumbs under the tape again; and when the hat is removed, your thumbs will appear tied as at first. After performing the trick, convey the tape away, lest it be detected.

MORE THAN FULL.

Fill a glass to the brim with water, and you may add to it spirit of wine without causing the water to overflow.

FLOATING NEEDLES.

Fill a cup with water, gently lay on its surface small fine needles, and they will float.

THE KNOTTED THREAD.

Considerable amusement, not unmixed with wonder, may be occasioned among a party of ladies, by a clever performance of this trick. It is most frequently performed by a female, but the effect of it is considerably increased when it is displayed by a youth. A piece of calico, muslin, or linen, is taken in the left hand, a needle is threaded in the presence of the spectators, and the usual, or even a double or treble knot, made at the extremity of one of the ends of it. The operator commences his work by drawing the needle and the thread in it quite through the linen, notwithstanding the knot, and continues to make several stitches in like manner successively.

The mode of performing this seeming wonder is as follows: A bit of thread, about a quarter of a yard long, is turned once round the top of the middle finger of the right hand, upon which a thimble is then placed, to keep it secure. This must be done privately, and the thread kept concealed, while a needle is threaded with a bit of thread of a similar length. The thread in the needle must have one of its ends drawn up nearly close, and be concealed between the forefinger and thumb; the other should hang down nearly as long as, and by the side of the thread, which is fastened under the thimble, so that these two may appear to be the two ends of the thread. The end of the piece that is fastened under the thimble is then knotted, and the performer begins to sew, by moving his hand quickly after he has taken up the stitch. It will appear as though he actually passed the knotted thread through the cloth.

THE BACCHUS EXPERIMENT.

This experiment, showing the elasticity of air, is performed with a pleasing toy. It represents a figure of Bacchus sitting across a cask, in which are two separate compartments. Put into one of them a portion of wine or colored liquid, and place the apparatus under the exhausted receiver of an air-pump, when the elastic force of the confined air will cause the liquid to ascend a transparent glass tube (fitted on purpose), into the mouth of the Bacchanalian figure. To render the experiment more striking, a bladder, with a small quantity of air therein, is fastened around the figure, and covered with a loose silken robe, when the air in the bladder will expand, and produce an apparent increase in the bulk of the figure, as if occasioned by the excess of liquor drunk.

CURIOUS METHOD OF MEASURING THE HEIGHT OF A TREE.

To ascertain the height of an object a peculiar method of measurement is in use among the Isthmus Indians. In measuring the height of a tree, for instance, a man proceeds from its base to a point where, on turning the back towards it, and putting the head between the legs, he can just see the top; at the spot where he is able to do this he makes a mark on the ground to the base of the tree; this distance will be equal to the height.

THE TRANSPOSABLE PIECES.

Take two quarter eagles and two dimes, and grind part of them away, on one side only, so that they may be but half the common thickness; and observe, that they must be quite thin at the edge; then rivet a quarter eagle and a dime together. Lay one of these double pieces, with the dime upwards, on the palm of your hand, at the bottom of your three first fingers, and lay the other piece with the quarter eagle upwards in like manner, in the other hand. Let the company take notice in which hand is the quarter eagle, and in which is the dime. Then, as you shut your hands, you naturally turn the pieces over, and when you open them again, the dime and the quarter eagle will appear to have changed their places.