  Take half a pound of pure dry nitrate, in powder; put it into a retort that is quite dry; add an equal quantity of highly rectified oil of vitriol, and, distilling the mixture in a moderate sand heat, it will produce a liquor like a yellowish fume; this, when caught in a dry receiver, is Glauber's Spirits of Nitre; probably the preparation, under that name, may be obtained of the chemists, which will of course save much time and trouble. You then put a drachm of distilled oil of cloves, turpentine, or carraways, in a glass vessel; and if you add an equal quantity, or rather more, of the above spirit, though both are in themselves perfectly cold, yet, on mixing them together, a great flame will arise and destroy them both, leaving only a little resinous matter at the bottom. The Exploding Bubble.If you take up a small quantity of melted glass with a tube, (the bowl of a common tobacco-pipe will do,) and let a drop fall into a vessel of water, it will chill and condense with a fine spiral tail, which being broken, the whole substance will burst with a loud explosion, without injury either to the party that holds it, or him that breaks it; but if the thick end be struck, even with a hammer, it will not break. The Magic Picture.Take two level pieces of glass, (plate glass is the best,) about three inches long and four wide, exactly of the same size; lay one on the other, and leave a space between them Join these glasses together at the edges by a composition of lime slaked by exposure to the air, and white of an egg. Cover all the edges of these glasses with parchment or bladder, except at one end, which is to be left open to admit the following composition. Dissolve, by a slow fire, six ounces of hogs'-lard, with half an ounce of white wax; to which you may add an ounce of clear linseed oil. This must be poured in a liquid state, and before a fire, between the glasses, by the space left in the sides, and which you are then to close up. Wipe the glasses clean, and hold them before the fire, to see that the composition will not run out at any part. Then fasten with gum a picture or print, painted on very thin paper, with its face to one of the glasses, and, if you like, you may fix the whole in a frame. While the mixture between the glasses is cold, the picture will be quite concealed, but become transparent when held to the fire; and, as the composition cools, it will gradually disappear. Artificial Lightning.Provide a tin tube that is larger at one end than it is at the other, and in which there are several holes. Fill this tube with powdered resin; and when it is shook over the flame of a torch, the reflection will produce the exact appearance of lightning. Artificial Thunder.Mix two drachms of the filings of iron, with one ounce of concentrated spirit of vitriol, in a strong bottle that holds about a quarter of a pint; stop it close, and in a few minutes shake the bottle; then taking out the cork, put a lighted candle near its mouth, which should be a little inclined, and you will soon observe an inflammation arise from the bottle, attended with a loud explosion. To guard against the danger of the bottle bursting, the best way would be to bury it in the ground, and apply the light to the mouth by means of a taper fastened to the end of a long stick. Another way.Mix three ounces of saltpetre, two ounces of salt of tartar, and two ounces of sulphur; roll the mixture up into a ball, of which take a quantity, about the size of a hazel-nut, and, placing it in a ladle or shovel over the fire, the explosion will resemble a loud clap of thunder. You will produce a much more violent commotion if you double or treble the quantity of the last experiment; suppose you put two or three ounces of the mixture into the shovel. For fear of accidents, it should not be done in the house, but by placing the shovel over a chafing-dish of very hot coals, in the open air, standing a great distance off. Common prudence will dictate the necessity of using great care in the above experiments, as an accident will soon happen if a person does not get out of the way before the composition explodes. Money augmented by an Optical Illusion.In a large drinking-glass of a conical shape, (small at the bottom and wide at the top,) put a shilling, and let the glass be half full of water; then place a plate on the top of it, and turn it quickly over, that the water may not escape. You will see on the plate a piece of coin of the size of half-a-crown; and a little higher up another the size of a shilling. It will add to the amusement this experiment affords, by giving the glass to any one in company, (but who, of course, has not witnessed your operations,) and, desiring him to throw away the water, but save the pieces, he will not be a little surprised at finding only one. Three objects discernible only with both Eyes.If you fix three pieces of paper against the wall of a room at equal distances, at the height of your eye, placing yourself directly before them, at a few yards' distance, and close your right eye, and look at them with your left, you will see only two of them, suppose the first and second; alter the position of your eye, and you will see the first and third: alter your position a second time, you will see the second To construct the Camera Obscura.Make a circular hole in the shutter of a window, from whence there is a prospect of some distance; in this hole place a magnifying glass, either double or single, whose focus is at the distance of five or six feet; no light must enter the room but through this glass. At a distance from it, equal to its focus, place a very white pasteboard, (what is called a Bristol board, if you can procure one large enough, will answer extremely well;) this board must be two feet and a half long, and eighteen or twenty inches high, with a black border round it: bend the length of it inward to the form of part of a circle, whose diameter is equal to double the focal distance of the glass. Fix it on a frame of the same figure, and put it on a moveable foot, that it may be easily placed at that distance from the glass, where the objects appear to the greatest perfection. When it is thus placed, all the objects in front of the window will be painted on the paper in an inverted position, with the greatest regularity, and in the most natural colours. If you place a swing looking-glass outside the window, by turning it more or less, you will have on the paper all the objects on each side the window. If, instead of placing the looking-glass outside the window, you place it in the room above the hole, (which must then be made near the top of the shutter,) you may have the representation on a paper placed horizontally on a table, and draw at your leisure all the objects reflected. Observe, the best situation is directly north; and the best time of the day is noon. The Magnifying Reflector.Let the rays of light that pass through the magnifying glass in the shutter be thrown on a large concave mirror, properly fixed in a frame. Then take a third strip of glass, and stick any small object on it; hold it in the intervening To tell by a Watch Dial the Hour when a Person intends to rise.The person is told to set the hand of his watch at any hour he pleases, which hour he tells you; and you add in your mind 12 to it. You then desire him to count privately the number of that addition on the dial, commencing at the next hour to that at which he intends to rise, and including the hour at which he has placed the hand, which will give the answer: for example. A intends to rise at 6, (this he conceals to himself;) he places the hand at 8, which he tells B, who, in his own mind, adds 12 to 8, which makes twenty. B then tells A to count twenty on the dial, beginning at the next hour to that at which he proposes to rise, which will be 5, and counting backwards, reckoning each hour as one, and including in his addition the number of the hour the hand is placed at, the addition will end at 6, which is the hour proposed; thus,
A person having an even Number of Shillings in one Hand, and an odd Number in the other, to tell in which hand the odd or even Number is.You desire the person to multiply the number in his right hand by an odd figure, and the number in his left by an even one; and tell you if the products, added together, be odd or even. If even, the even number is in the right hand; if odd, the even number is in the left. For instance,
Secret Correspondence.To carry on a correspondence without the possibility of the meaning of the letter being detected, in case it should Fig. 1. Fig. 1. Provide a piece of square card or pasteboard, and draw a circle on it, which circle is to be divided into 27 equal parts, in each of which parts must be written one of the capital letters of the alphabet, and the &, as in the figure. Let the centre of this circle be blank. Then draw another circle, also divided into 27 equal parts, in each of which write one of the small letters of the alphabet, and the &. This circle must be cut round, and made exactly to fit the blank space in the centre of the large circle, and must run round a pivot or pin. The person with whom you correspond must have a similar dial, and at the beginning of your letter you must put the capital letter, and at the end the small letter, which answer to each other when you have fixed your dial. Suppose what you wish to communicate is as follows: I am so watched I cannot see you as I promised; but I will meet you to-morrow in the park, with the letters, &c. You begin with the letter T, and end with the letter m, which shows how you have fixed the dial, and how your correspondent must fix his, that he may decipher your letter. Then, for I am, you write b uf, and so of the rest, as follows. T b uf lh pumrvayx b rvugghm lyy rhn ul b ikhfblyx vnm b pbee fyym rhn mh-fhkkhp bg may iukd pbma may eymmykl, tw. m. Another Way.Take two pieces of card, pasteboard, or stiff paper, through which you cut long squares at different distances. One of these you keep yourself, and the other you give to your correspondent. You lay the pasteboard on a paper, and, in the spaces cut out, write what you would have understood by him only; then fill the intermediate spaces with any words that will connect the whole together, and make a different sense. When he receives it, he lays his pasteboard over the "Don't trust Robert: I have found him a villain." "[Don't] fail to send my books. I [trust] they will be ready when [Robert] calls on you. [I have] heard that you have [found] your dog. I call [him a villain] who stole him." You may place a pasteboard of this kind three other ways—the bottom at top—the top at bottom, or by turning it over; but in this case you must previously apprize your correspondent, or he may not be able to decipher your meaning. Secret Correspondence by Music.Form a circle like Fig. 2, divided into twenty-six parts, with a letter of the alphabet written in each. The interior of the circle is moveable, like that in Fig. 1, and the circumference is to be ruled like music-paper. Place in each division a note different in figure or position. Fig. 2. Fig. 2. Within the musical lines place the three keys, and on the outer circle the figures to denote time. Then get a ruled paper, and place one of the keys (suppose ge-re-sol) against the time 2-4ths, at the beginning of the paper, which will inform your correspondent how to place his circle. You then The Magic Vessel.On the bottom of a vessel, lay three pieces of money, the first at A, the second at B, and the third at C, Fig. 3. Then place a person at D, where he can see no farther into the vessel than E. You tell him, that by pouring water in the vessel you will make him see three different pieces of money; and bid him observe, that you do not convey any money in with the water. But be careful that you pour the water in very gently, or the pieces will move out of their places, and thereby destroy the experiment. Fig. 3. Fig. 3. When the water rises up to F, the piece at A will be visible; when it reaches G, both A and B will be visible; and when it comes up to H, all three pieces will be visible. Artificial Earthquake and Volcano.Grind an equal quantity of fresh iron filings with pure sulphur, till the whole be reduced to a fine powder. Be careful not to let any wet come near it. Then bury about thirty pounds of it a foot deep in the earth, and in about six or eight hours the ground will heave and swell, and shortly after send forth smoke and flames like a burning mountain. If the earth is raised in a conical shape, it will be no bad miniature resemblance of one of the burning mountains. Artificial Illuminations.A very pleasing exhibition may be made with very little trouble or expense, in the following manner: Provide a box, which you fit up with architectural designs cut out on pasteboard; prick small holes in those parts of the building where you wish the illuminations to appear, observing, that in proportion to the perspective, the holes are to be made smaller; and on the near objects the holes are to be made larger. Behind these designs thus perforated, you fix a lamp or candle, but in such a manner that the reflection of the light shall only shine through the holes; then placing a light of just sufficient brilliance to show the design of the buildings before it, and making a hole for the sight at the front end of the box, you will have a very tolerable representation of illuminated buildings. The best way of throwing the light in front, is to place an oiled paper before it, which will cast a mellow gleam over the scenery, and not diminish the effect of the illumination. This can be very easily planned, both not to obstruct the sight, nor be seen to disadvantage. The lights behind the picture should be very strong; and if a magnifying glass were placed in the sight hole, it would tend greatly to increase the effect. The box must be covered in, leaving an aperture for the smoke of the lights to pass through. The above exhibition can only be shown at candle-light; but there is another way, by fixing small pieces of gold on the building, instead of drilling the holes; which gives something like the appearance of illumination, but by no means equal to the foregoing experiment. N.B. It would be an improvement, if paper of various colours, rendered transparent by oil, were placed between the The Cameleon Spirit.Put into a decanter volatile spirit, in which you have dissolved copper filings, and it will produce a fine blue. If the bottle be stopped, the colour will disappear; but when unstopped, it will return. This experiment may be often repeated. Invisible Ink.Put litharge of lead into very strong vinegar, and let it stand twenty-four hours. Strain it off, and let it remain till quite settled; then put the liquor in a bottle. You next dissolve orpiment in quick lime water, by setting the water in the sun for two or three days, turning it five or six times a-day. Keep the bottle containing this liquor well corked, as the vapour is highly pernicious if received into the mouth. Write what you wish with a pen dipped in the first liquor; and, to make it visible, expose it to the vapour of the second liquor. If you wish them to disappear again, draw a sponge or pencil, dipped in aqua fortis, or spirit of nitre, over the paper; and if you wish them to re-appear, let the paper be quite dry, and then pass the solution of orpiment over it. Another.Dissolve bismuth in nitrous acid. When the writing with this fluid is exposed to the vapour of liver of sulphur, it will become quite black. Another.Dissolve green vitriol and a little nitrous acid in common water. Write your characters with a new pen. Next infuse small Aleppo galls, slightly bruised in water. In two or three days, pour the liquor off. By drawing a pencil dipped in this second solution over the characters written with the first, they will appear a beautiful black. Invisible Gold Ink.Put as much gold in as small a quantity of aqua regia as will dissolve it, and dilute it with two or three times the quantity of distilled water. Next dissolve, in a separate vessel, fine pewter in aqua regia, and when it is well impregnated, add an equal quantity of distilled water. Write your characters with the first solution: let it dry in the shade. To make them visible, draw a pencil or sponge, dipped in the second solution, over the paper, and the characters will appear of a purple colour. Invisible Silver Ink.Dissolve fine silver in aqua fortis; and after the dissolution, add some distilled water in the same manner as in the gold ink. What is written with the above ink will remain invisible for three or four months, if kept from the air; but may be easily read in an hour, if exposed to the fire, air, or sun. Invisible Yellow Ink.Steep marigold flowers seven or eight days in clear distilled vinegar. Press the flowers and strain the liquor, which is to be kept in a bottle well corked. If you would have it still more clear, add, when you use it, some pure water. To make the characters visible, which you write with this ink, pass a sponge over the paper, dipped in the following solution: Take a quantity of flowers of pansy, or the common violet, bruise them in a mortar with water, strain the liquor in a cloth, and keep it in a bottle. Invisible Red Ink.To the pure spirit of vitriol or nitre, add eight times as much water. Use the above solution of violets to make visible the characters written with this ink. Invisible Green Ink.Dissolve salt of tartar, clean and dry, in a sufficient quantity of river water. Use the violet solution to render it visible. Another Invisible Green Ink.Dissolve zaffre, in powder, in aqua regia, for twenty-four hours. Pour the liquor off, and the same quantity of common water, and keep it in a bottle well corked. This ink will not be visible till exposed to the fire or the sun; and will again be invisible when it becomes cold. Invisible Violet Ink.Express the juice of lemons, and keep it in a bottle well corked. Use the violet infusion to make the writing visible. Invisible Grey Ink.Mix alum with lemon-juice. The letters written with this ink will be invisible till dipped in water. We now present our readers with a variety of amusing experiments, which may be performed by the foregoing inks; and they will, probably, suggest others equally amusing and useful. A Secret Correspondence by means of Invisible Ink.A person wishing to carry on a correspondence with another, and who is fearful of having his letter opened, or intercepted, can adopt the following plan: Write any unimportant matter with common ink, and let the lines be very wide apart: then between these lines write the communication you wish to make, with any of the above invisible inks you can most readily procure. Your correspondent is to be previously apprized of the method of making the characters visible: and writing in common ink will serve to lull the suspicions of those who might intercept the letter, and who, not finding any thing important in it, will either forward or keep it. In either The Mysterious Writing.Write on a piece of paper with common ink any question; then underneath it write the answer either in invisible silver ink, or the invisible green ink, made with zaffre and aqua regia, described in pages 24 and 25. You give this paper to your friend, and tell him to place it against the wall, or on his dressing-table, keeping the door locked, that he may be sure no person has entered his room: he will next day find the answer written on it. The Restored Flowers.Make a bouquet of artificial flowers; the leaves should be formed of parchment. Dip the roses in the red invisible ink, the jonquilles in the yellow, the pinks in the violet, and the leaves in the green ink. They will all appear white; and you show them to the company, observing, that you will restore them to their natural colours, and desiring any person to fix any private mark on them he pleases, that he may be sure there is no deception. You then, unperceived by the company, dip them in the revivifying liquor, used to make the yellow ink visible, described in page 24, and, drawing them gently out, that the liquor may drop, and the flowers have time to acquire their colours, you present them to the company, who will see, with surprise, that they each appear in their natural colours. Winter changed to Spring.Take a print that represents winter, and colour those parts which should appear green, with the second green invisible ink, described in page 25; observing, of course, the usual rules of perspective, by making the near parts deeper in colour than the others. The other objects must be painted in their natural colours. Then put the print into a frame with a glass, and cover the back with a paper that is pasted only at its extremities. When this print is exposed to a moderate fire, or the warm The Silver Tree.Dissolve an ounce of fine silver in three ounces of strong aqua fortis, in a glass bottle. When the silver is dissolved; pour the aqua fortis into another glass vessel, (a decanter will be best,) with seven or eight ounces of mercury, to which add a quart of common water; to the whole add your dissolved silver, and let it remain untouched. In a few days the mercury will appear covered with a number of little branches of a silver colour. This appearance will increase for a month or two, and will remain after the mercury is entirely dissolved. The Lead Tree.A more modern invention, and an easier method by far than the above, is the following: To a piece of zinc fasten a wire, crooked in the form of the worm of a still; let the other end of the worm be thrust through a cork. You then pour spring water into a phial or decanter, to which you add a small quantity of sugar of lead; thrust the zinc into the bottle, and with the cork at the end of the wire fasten it up. In a few days the tree will begin to grow, and produce a most beautiful effect. To produce beautiful Fire-works in Miniature.Put half a drachm of solid phosphorus into a large pint Florence flask; holding it slanting, that the phosphorus may not break the glass. Pour upon it a gill and a half of water, and place the whole over a tea-kettle lamp, or any common tin lamp, filled with spirit of wine. Light the wick, which should be almost half an inch from the flask; and as soon as the water is heated, streams of fire Artificial Rain and Hail.Make a hollow cylinder of wood; let it be very thin at the sides, about eight or ten inches wide, and two or three feet diameter. Divide its inside into five equal parts, by boards of five or six inches wide, and let there be between them and the wooden circle, a space of about one-sixth of an inch. You are to place these boards obliquely. In this cylinder put four or five pounds of shot that will easily pass through the opening. When turned upside down, the noise of the shot going through the various partitions will resemble rain; and if you put large shot, it will produce the sound of hail. Illuminated Writing.It is well known that if any words are written on a wall with solid phosphorus, the writing will appear as if on fire; A Lamp that will burn Twelve Months without replenishing.Take a stick of phosphorus, and put it into a large dry phial, not corked, and it will afford a light sufficient to discern any object in a room when held near it. The phials should be kept in a cool place, where there is no great current of air, and it will continue its luminous appearance for more than twelve months. Curious Transcolorations.Put half a table-spoonful of syrup of violets and three table-spoonfuls of water into a glass; stir them well together with a stick, and put half the mixture into another glass. If you add a few drops of acid of vitriol into one of the glasses and stir it, it will be changed into a crimson; put a few drops of fixed alkali dissolved into the other glass, and when you stir it, it will change to green. If you drop slowly into the green liquor, from the side of the glass, a few drops of acid of vitriol, you will perceive crimson at the bottom, purple in the middle, and green at the top; and by adding a little fixed alkali dissolved, to the other glass, the same colours will appear in different order. Another.If you put a tea-spoonful of a liquor composed of copper infused in acid of vitriol, into a glass, and add two or three table-spoonfuls of water to it, there will be no sensible colour produced; but if you add a little volatile alkali to it, and stir it, you will perceive a very beautiful blue colour. Add a little acid of vitriol, the colour will instantly disappear upon Another.Put half a tea-spoonful of a liquor composed of iron infused in acid of vitriol, into half a glass of water; and add a few drops of phlogisticated alkali, and a beautiful Prussian blue will appear. Curious Account of the Electric Effects of a Russian Climate.Mr. Æpinus in a letter to Dr. Guthrie, relates the following phenomena, which took place in Russia, when a severe frost had continued for several weeks. Mr. Æpinus was sent for to the palace to see an uncommon phenomenon. On going into the apartment of Prince Orloff, he found him at his toilet, and that every time his valet drew the comb through his hair, a strong crackling noise was heard; and on darkening the room, sparks were seen following the comb in great abundance, while the prince himself was so completely electrified, that strong sparks could be drawn from his hands and face; nay, he was even electrified when he was only powdered with a puff. A few days after, he was witness to a more striking effect of the electric state of a Russian atmosphere. The Grand Duke of Russia sent for him one evening in the twilight, and told him, that having briskly drawn a flannel cover off a green damask chair in his bed-chamber, he was astonished at the appearance of a strong bright flame that followed; but considering it as an electrical appearance, he had tried to produce a similar illumination on different pieces of furniture, and could then show him a beautiful and surprising experiment. His highness threw himself on his bed, which was covered with a damask quilt, laced with gold; and, rubbing it with his hands in all directions, the young prince, who had then reached his twelfth year, appeared swimming in fire, as at every stroke flames arose all around him, darted to the gold-laced border, ran along it, and up to that of the bed, and even to the very top. While he was showing this experiment, Prince Orloff came into the room, with a sable muff in his hand, and showed us, that by only whirling it five or six times round his head in the air, he could electrify himself so strongly, as to send out sparks from all the uncovered parts of his body. Astonishing Power of Steam.If you put a small quantity of water into a tea-kettle, and place it on the fire, it will disappear in a short time, having escaped in the steam. But if its escape be prevented by stopping up the spout and crevices, it will force its way by bursting the vessel in which it was confined. If the steam of boiling water be at liberty, the water never attains more than a certain degree of heat; but if confined in a close vessel, the additional fire not escaping, the power of the steam is increased, it re-acts upon the water, and raises the heat so much higher, that it would keep lead in a melting state; and so penetrating, that it would soften the marrow-bone of an ox, in a few minutes. There is an instrument contrived for the foregoing purposes, called Papin's Digester, from the name of its inventor, and from its digestive powers on substances exposed to its action. It is a very strong vessel, made of copper, fitted with a thick close cover, and fastened down by several strong screws, so as to render it steam-tight in great degrees of heat. To render it safe, while being used, there is a valve on the cover, to let out the steam, when it is too violent; this valve is kept down by a steel-yard, with a weight moveable upon it, to regulate the degrees of the steam within. The following account of an accident with one of these instruments, will give some idea of the great force of steam. Mr. Papin (the inventor) having fixed all things right, and included about a pint of water, with two ounces of marrow-bone, he placed the vessel horizontally between the bars of the grate, about half-way into the fire. In three minutes he found it raised to a great heat, and perceiving the heat in a very short time become more raging, stepped to a side-table for an iron to take the digester out of the fire, The following accident was attended with more fatal consequences. A steam-engine was repairing at Chelsea, and, as the workmen were endeavouring to discover the defect, the boiler suddenly exploded, and a cloud of steam rushing out at the fracture, struck one of the men who was near it, like a blast of lightning, and killed him in a moment; when his companions endeavoured to take off his clothes, the flesh came off with them from the bones. Account of the Wonderful Effects of two immense Burning-Glasses.Mr. de Tschirnhausen constructed a burning-glass, between three and four feet in diameter, and whose focus was rendered more powerful by a second one. This glass melted tiles, slates, pumice-stone, &c., in a moment; pitch, and all resins, were melted even under water; the ashes of vegetables, wood, and other matters, were converted into glass; indeed, it either melted, calcined, or dissipated into smoke, every thing applied to its focus. Mr. Parker, of Fleet-street, made a burning-glass, three feet in diameter; it was formed of flint glass, and when on its frame, exposed a surface of 2 feet 8½ inches to the solar rays. It had a small glass fitted to it, to converge the rays, and heighten the effect. The experiments made by it were more powerful and accurate than those performed by any other glass. The following is a brief epitome of its astonishing power.
Fulminating Powder.This powder is made by rubbing together, in a hot marble mortar, with a wooden pestle, three parts, by weight, of nitre, two of mild vegetable alkali, and one of flowers of sulphur, A more powerful fulminating Powder.The most wonderful instance of chemical detonation is formed by the combination of volatile alkali with silver. Gunpowder, or fulminating gold, are not to be compared with this invention, and the great danger attending its manufacture prevents us from giving a methodical account of its preparation to our readers, particularly as it can be purchased, properly prepared, of the chemists. The slightest agitation or friction is sufficient to cause its explosion. When it is once obtained, it can no longer be touched with safety. The falling of a few atoms of it, from a small height, produces an explosion; a drop of water falling on it has the same effect. No attempt, therefore, can be made to enclose it in a bottle, but it must be let alone in the capsule, wherein, by evaporation, it obtains this terrible property. To make this experiment with safety, no greater quantity than a grain of silver should be used; the last process of drying should be made in a metallic vessel, and the face of the operator defended by a mask with strong glass eyes. To make the Phosphorus Match Bottles.Nothing more is necessary for this purpose, than to drop small pieces of dry phosphorus into a common phial; gently heat it till it melts; and then turn the bottle round, that it may adhere to the sides. The phial should be closely corked; and when used, a common brimstone match is to be introduced, and rubbed against the sides of the phial: this inflames the match when it is brought out of the bottle. Though there is no danger in phosphorus, till friction, or fire, is applied, yet persons cannot be too cautious in the use of it, as instances have been known of one of these bottles catching fire in the pocket, and very much endangering the person who carried it; likewise, if carelessly used, small particles are apt to get under the nails, or on the hand; and if, by accident, they are held to the fire, or rubbed together, a flame will presently kindle. To make a Ring suspend by a Thread, after the Thread has been burned.Soak a piece of thread in urine, or common salt and water. Tie it to a ring, not larger than a wedding-ring. When you apply the flame of a candle to it, it will burn to ashes, but yet sustain the ring. To form Figures in relief on an Egg.Design on the shell any figure or ornament you please, with melted tallow, or any other fat oily substance; then immerse the egg into very strong vinegar, and let it remain till the acid has corroded that part of the shell which is not covered with the greasy matter: those parts will then appear in relief, exactly as you have drawn them. To give a ghastly Appearance to Persons in a Room.Dissolve salt in an infusion of saffron and spirits of wine. Dip some tow in this solution, and, having set fire to it, extinguish all other lights in the room. To change Blue to White.Dissolve copper filings in a phial of volatile alkali; when the phial is unstopped, the liquor will be blue; when stopped, it will be white. Magical Transmutations.Infuse a few shavings of logwood in common water, and when the liquor is sufficiently red, pour it into a bottle. Then take three drinking-glasses, and rinse one of them with strong vinegar; throw into the second a small quantity of pounded alum, which will not be observed if the glass has been recently washed, and leave the third without any preparation. If the red liquor in the bottle be poured into the first glass, it will appear of a straw colour; if into the second, it will pass gradually from bluish-grey to black, when stirred with a key, or any piece of iron, which has been previously dipped in strong vinegar. In the third glass, the red liquor will assume a violet tint. To make Pomatum with Water and Wax.Water and wax are two substances that do not naturally unite together; therefore, to those who witness the following process, without knowing the cause, it will have the appearance of marvellous. Put into a new glazed earthen pot, six ounces of river water and two ounces of white wax, in which, you must previously conceal a strong dose of salt of tartar. If the whole be then exposed to a considerable degree of heat, it will assume the consistence of pomatum, and may be used as such. Iron transformed into Copper.Dissolve blue vitriol in water, till the water is well impregnated with it; and immerse into the solution small plates of iron, or coarse iron filings. These will be attacked and dissolved by the acid of the vitriol, while the copper naturally contained in the vitriol will be sunk and deposited in the place of the iron dissolved. If the piece of iron be too large for dissolving, it will be so completely covered with particles of copper, as to resemble that metal itself. Iron transformed into Silver.Dissolve mercury in marine acid, and dip a piece of iron into it, or rub the solution over the iron, and it will assume a silver appearance. It is scarcely necessary to say, that these transmutations are only apparent, though to the credulous it would seem that they were actually transformed. Chemical Illuminations.Put into a middling-sized bottle, with a short wide neck, three ounces of oil or spirit of vitriol, with twelve ounces of common water, and throw into it, at different times, an ounce or two of iron filings. A violent commotion will then take place, and white vapours will arise from the mixture. If a taper be held to the mouth of the bottle, these vapours will inflame and produce a violent explosion, which may be repeated as long as the vapours continue. The Philosophical Candle.Provide a bladder, into the orifice of which is inserted a metal tube, some inches in length, that can be adapted to the neck of a bottle, containing the same mixture as in the last experiment. Having suffered the atmospheric air to be expelled from the bottle, by the elastic vapour produced by the solution, apply the orifice of the bladder to the mouth of the bottle, after carefully squeezing the common air out of it, (which you must not fail to do, or the bladder will violently explode.) The bladder will thus become filled with the inflammable air, which, when forced out against the flame of a candle, by pressing the sides of the bladder, will form a beautiful green flame. To make the appearance of a Flash of Lightning, when any one enters a Room with a lighted Candle.Dissolve camphor in spirit of wine, and deposit the vessel containing the solution in a very close room, where the spirit of wine must be made to evaporate by strong and speedy boiling. If any one then enters the room with a lighted candle, the air will inflame, while the combustion will be so sudden, and of so short a duration, as to occasion no danger. To melt Iron in a Moment and make it run into Drops.Bring a bar of iron to a white heat, and then apply to it a roll of sulphur. The iron will immediately melt and run into drops. This experiment should be performed over a basin of water, in which the drops that fall down will be quenched. These drops will be found reduced into a sort of cast-iron. Never-yielding Cement.Calcine oyster-shells, pound them, sift them through a silk sieve, and grind them on porphyry till they are reduced to the finest powder. Then take the whites of several eggs, according to the quantity of the powder; To remove Stains and Blemishes from Prints.Paste a piece of paper to a very smooth clear table, that the boiling water used in the operation may not require a colour which might lessen its success. Spread out the print you wish to clean upon the table, and sprinkle it with boiling water; taking care to moisten it throughout by very carefully applying a very fine sponge. After you have repeated this process five or six times, you will observe the stains or spots extend themselves; but this is only a proof that the dirt begins to be dissolved. After this preparation, lay the print smoothly and carefully into a copper or wooden vessel, larger than the size of the print. Then cover it with a boiling ley of potash, taking care to keep it hot as long as possible. After the whole is cooled, strain off the liquor, take out the print with care, spread it on a stretched cord, and when half dry, press it between leaves of white paper, to prevent wrinkles. By this process, spots and stains of any kind will be effectually removed. To so fill a Glass with Water, that it cannot be removed without spilling the whole.This is a mere trick, but may afford some amusement. You offer to bet any person that you will so fill a glass with water that he shall not move it off the table without spilling the whole contents. You then fill the glass, and, laying a piece of paper or thin card over the top, you dexterously turn the glass upside down on the table, and then drawing away the paper, you leave the water in the glass, with its foot upwards. It will therefore be impossible to remove the glass from the table without spilling every drop. Two Figures, one of which blows out and the other re-lights a Candle.Make two figures, of any shape or materials you please; insert in the mouth of one a small tube, at the end of which is a piece of phosphorus, and in the mouth of the other a tube containing at the end a few grains of gunpowder; taking care that each be retained in the tube by a piece of paper. If the second figure be applied to the flame of a taper, it will extinguish it; and the first will light it again. A vessel that will let Water out at the Bottom, as soon as the Mouth is uncorked.Provide a tin vessel, two or three inches in diameter, and five or six inches in height, having a mouth about three inches in width; and in the bottom several small holes, just large enough to admit a small needle. Plunge it in water with its mouth open, and when full, while it remains in the water, stop it very closely. You can play a trick with a person, by desiring him to uncork it; if he places it on his knee for that purpose, the moment it is uncorked the water will run through at the bottom, and make him completely wet. A Powder which catches Fire when exposed to the Air.Put three ounces of rock alum, and one ounce of honey or sugar, into a new earthen dish, glazed, and which is capable of standing a strong heat; keep the mixture over the fire, stirring it continually till it becomes very dry and hard; then remove it from the fire, and pound it to a coarse powder. Put this powder into a long-necked bottle, leaving a part of the vessel empty; and, having placed it in a crucible, fill up the crucible with fine sand, and surround it with burning coals. When the bottle has been kept at a red heat for about seven or eight minutes, and no more vapour issues from it, remove it from the fire, then stop it with a piece of cork; and, having suffered it to cool, preserve the mixture in small bottles well closed. If you unclose one of these bottles, and let fall a few grains of this powder on a bit of paper, or any other very Fulminating Gold.Put into a small long-necked bottle, resting on a little sand, one part of fine gold filings, and three parts of aqua regia, (nitro-muriatic acid.) When the gold is dissolved, pour the solution into a glass, and add five or six times the quantity of water. Then take spirit of sal ammoniac or oil of tartar, and pour it drop by drop into the solution, until the gold is entirely precipitated to the bottom of the glass. Decant the liquor that swims at the top, by inclining the glass; and, having washed it several times in warm water, dry it at a moderate heat, placing it on paper capable of absorbing all the moisture. If a grain of this powder, put into a spoon, (it should be an iron one,) be exposed to the flame of a candle, it will explode with a very loud report. 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 nitre, one part of flowers of sulphur, and a little saw-dust 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. A Liquid that Shines in the Dark.Take a bit of phosphorus, about the size of a pea; break it into small parts, which you are to put into a glass half full of very pure water, and boil it in a small earthen vessel, over a very moderate fire. Have in readiness a long narrow bottle, with a well-fitted glass stopper, and immerse it, with its mouth open, into boiling water. On This water will shine in the dark for several months, even without being touched; and, if it be shaken in dry warm weather, brilliant flashes will be seen to rise through the middle of the water. Luminous Liquor.Put a little phosphorus, with essence of cloves, into a bottle, which must be kept closely stopped. Every time the bottle is unclosed, the liquor will appear luminous. This experiment must be performed in the dark. The changeable Rose.Take a common full-blown rose, and, having thrown a little sulphur finely pounded into a chafing-dish with coals, expose the rose to the vapour. By this process the rose will become whitish; but if it be afterwards held some time in water, it will resume its former colour. Golden Ink.Take some white gum arabic, reduce it to an impalpable powder, in a brass mortar; dissolve it in strong brandy, and add a little common water to render it more liquid. Provide some gold in a shell, which must be detached, in order to reduce it to a powder. When this is done, moisten it with the gummy solution, and stir the whole with a small hair-brush, or your finger; then leave it for a night, that the gold may be better dissolved. If the composition become dry during the night, dilute it with more gum water, in which a little saffron has been infused; but take care that the gold solution be sufficiently liquid to flow freely in a pen. When the writing is dry, polish it with a dry tooth. Another way.Reduce gum ammoniac into powder, and dissolve it in gum arabic water, to which a little garlic juice has been White Ink, for Writing on black Paper.Having carefully washed some egg-shells, remove the internal skin, and grind them on a piece of porphyry. Then put the powder into a small vessel of pure water, and when it has settled at the bottom, draw off the water, and dry the powder in the sun. This powder must be preserved in a bottle; when you want to use it, put a small quantity of gum ammoniac into distilled vinegar, and leave it to dissolve during the night. Next morning the solution will appear exceedingly white; and if you then strain it through a piece of linen cloth, and add to it the powder of egg-shells, in sufficient quantity, you will obtain a very white ink. To construct Paper Balloons.Take several sheets of silk paper; cut them in the shape of a spindle; or, to speak more familiarly, like the coverings of the sections of an orange; join these pieces together, into one spherical or globular body, and border the aperture with a ribbon, leaving the ends, that you may suspend them from the following lamp. Construct a small basket of very fine wire, if the balloon is small, and suspend it from the aperture, so that the smoke from the flame of a few leaves of paper, wrapped together, and dipped in oil, may heat the inside of it. Before you light this paper, suspend the balloon in such a manner, that it may, in a great measure, be exhausted of air, and as soon as it has been dilated, let it go, together with the wire basket, which will serve as ballast. Water-Gilding upon Silver.Take copper-flakes, on which pour strong vinegar; add alum and salt in equal quantities; set them on a fire, and when the vinegar is boiled, till it becomes one-fourth part of its original quantity, throw into it the metal you design to gild, and it will assume a copper colour. Continue boiling it, and it will change into a fine gold colour. A Water which gives Silver a Gold Colour.Take sulphur and nitre, of each an equal quantity; grind them together very fine, and put them into an unglazed vessel; cover and lute it well; then set it over a slow fire for 24 hours; put what remains into a strong crucible, and let it dissolve; put it into a phial, and whatever silver you anoint with it will have a gold colour. To make an old Gold Chain appear like new.Dissolve sal ammoniac in urine, boil the chain in it, and it will have a fine gold colour. To give Silver the Colour of Gold.Dissolve in common aqua fortis as much silver as you please. To eight ounces of silver, take four ounces of hepatic aloes, six ounces of turmeric, and two ounces of prepared tutty, that has been several times quenched in urine. Put these to the solution of the silver; they will dissolve, but rise up in the glass like a sponge; this glass must therefore be large, to prevent running over. Then draw it off, and you will have ten ounces of silver as yellow as gold. A Water to give any Metal a Gold Colour.Take fine sulphur and pulverize it; then boil some stale spring water; pour it hot upon the powder, and stir it well together; boil it again, and pour into it an ounce of dragon's blood. After it is well boiled, take it off, and filter it through a fine cloth; pour this water into a matrass, (a chemical Another way.Take hepatic aloes, nitre, and Roman vitriol, of each equal quantities; and distil them with water, in an alembic, till all the spirits are extracted; it will at last yield a yellowish water, which will tinge any sort of metal of a gold colour. To give Silver-plate a Lustre.Dissolve alum in a strong ley, and scum it carefully; then mix it up with soap, and wash your silver utensils with it, using a linen rag. The Fiery Fountain.If twenty grains of phosphorus, cut very small, and mixed with forty grains of powder of zinc, be put into four drachms of water, and two drachms of concentrated sulphuric acid be added thereto, bubbles of inflamed phosphoretted hydrogen gas will quickly cover the whole surface of the fluid in succession, forming a real fountain of fire. To take Impressions of Coins, Medals, &c.Cut fish-glue, or isinglass, into small pieces, immerse it in clear water, and set it on a slow fire; when gradually dissolved, let it boil slowly, stirring it with a wooden spoon, and taking off the scum. The liquor being sufficiently adhesive, take it off the fire, let it cool a little, and then pour it on the medal or coin you wish to copy, having first rubbed the coin over with oil. Let the composition lay about the thickness of a crown-piece on the medal. Then set it in a moderate air, neither too hot nor too cold, and let it cool and dry. When it is dry, it will loosen itself; you will find the impression correct, and the finest strokes expressed with the greatest accuracy. You may give a most pleasing effect to the composition, by mixing any colour with it, red, yellow, blue, green, &c., and if you add a little parchment size to it, it will make it To tell a Person any Number he may privately fix on.When the person has fixed on a number, bid him double it and add four to that doubling; then multiply the whole by 5; to the product let him add 12, and multiply the amount by 10. From the total of all this, let him deduct 320, and tell you the remainder; from which, if you cut off the two last figures, the number that remains will be what he fixed upon. For instance,
To tell any Number a Person has fixed on, without asking him any Questions.You tell the person to choose any number from 1 to 15; he is to add 1 to that number, and triple the amount. Then, 1. He is to take the half of that triple, and triple that half. Thus, it will be seen, there are four cases where the half is to be taken; the three first are denoted by one of the eight following Latin words, each word being composed of three syllables; and those that contain the letter i refer to those cases where the half cannot be taken without a fraction; therefore, in those cases, the person who makes the deduction is to add 1 to the number divided. The fourth case shows which of the two numbers annexed to every word has been chosen; for if the fourth half can be taken without adding 1, the number chosen is in the first column; but if not, it is in the second.
For example:
While the person is performing the operation, you remark, that at the second and third stages he is obliged to add 1; and, consequently, that the word ob-tin-git, in the second and third syllables of which is an i, denotes that the number must be either 1 or 9; and, by observing that he cannot take the last half without adding 1, you know that it must be the number in the second column. If he makes no addition at any one of the four stages, the number he chose must be 15, as that is the only number that has not a fraction at either of the divisions. The Lamp Chronometer.Figure 4 represents a chamber lamp, A, consisting of a cylindrical vessel made of tin, in the shape of a candle, and is to be filled with oil. This vessel should be about three inches high and one inch diameter, placed in a stand, B. Fig. 4. Fig. 4. Now, as the distance of the style from the flame of the lamp is only half an inch, then, if the distance of the frame from the style be six inches, while the float that contains the light descends by the decrease on the oil, one inch, the shadow of the style of the frame will ascend 12 inches, being its whole length, and show by its progression, the regular increase of the hours, with their several divisions. You must be careful always to burn the same oil, which The Phial of the Four Elements.Take a phial, six or seven inches long, and about three quarters of an inch in diameter. In this phial put, first, glass coarsely powdered; secondly, oil of tartar per deliquum; thirdly, tincture of salt of tartar; and lastly, distilled rock oil. The glass and the various liquors being of different densities, if you shake the phial, and then let it rest a few moments, the three liquors will entirely separate, and each assume its place; thus forming no indifferent resemblance of the four elements, earth, fire, water, and air: the powdered glass (which should be of some dark colour) representing the earth; the oil of tartar, water; the tincture, air; and the rock oil, fire. The Magic Bottle.Take a small bottle, the neck of which is not more than the sixth of an inch in diameter. With a funnel, fill the bottle quite full of red wine, and place it in a glass vessel, similar to a show-glass, whose height exceeds that of the bottle about two inches; fill this vessel with water. The wine will shortly come out of the bottle, and rise in the form of a small column to the surface of the water; while at the same time, the water, entering the bottle, will supply the place of the wine. The reason of this is, that as water is specifically heavier than wine, it must hold the lower place, while the other rises to the top. An effect equally pleasing will be produced, if the bottle be filled with water, and the vessel with wine. The Globular Fountain.Make a hollow globe, of copper or lead, and of a size adapted to the quantity of water that comes from a pipe (hereafter mentioned) to which it is to be fixed, and which may be fastened to any kind of pump, provided it be so constructed, that the water shall have no other means of escape than through the pipe. Pierce a number of small The Hydraulic Dancer.Procure a little figure made of cork, which you may dress as your fancy dictates. In this figure place a small hollow cone made of thin leaf brass. When the figure is placed on a jet d'eau, that plays in a perpendicular direction, it will be suspended on the top of the water, and perform a great variety of amusing motions. If a hollow ball of very thin copper, of an inch diameter, be placed on a similar jet, it will remain suspended, turning round, and spreading the water all about it. A Person having put a Ring an one of his Fingers, to name the Person, the Hand, the Finger, and the Joint on which it is placed.Let a third person double the number of the order in which he stands who has the ring, and add 5 to that number; then multiply that sum by 5, and to the product add 10. Let him next add 1 to the last number, if the ring be on the right hand, and 2 if on the left, and multiply the whole by 10: to the product of this he must add the number of the finger, (counting the thumb as the first finger,) and multiply the whole again by 10. Let him then add the number of the joint, and, lastly, to the whole join 35. He is then to tell you the amount of the whole, from which you are to subtract 3535, and the remainder will consist of four figures; the first of which will express the rank in which the person stands, the second the hand, (number 1 signifying the right, and 2 the left,) the third number the finger, and the fourth the joint.—For example: Suppose the person who stands the third in order has put the ring upon the second joint of the thumb of his left hand; then,
Of which, as we have said, the 3 denotes the third person, the 2 the left hand, the 1 the thumb, and the last 2 the second joint. The Water Sun.Provide two portions of a hollow sphere, that are very shallow; join them together in such a manner that the hollow between them be very narrow. Fix them vertically to a pipe from whence a jet proceeds. Bore a number of small holes all around that part where the two pieces are joined together. The water rushing through the holes will form a very pleasing water sun, or star. The Magical Cascade.Fig. 5. Fig. 5. Procure a tin vessel, shaped like Fig. 5, about five inches high and four in diameter, with a cover, C, closed at top. Place this machine in a tin basin, G H, with a hole in the middle, about a quarter of an inch in diameter. Fix to the tube D E, any sort of ornament that will keep the machine firm on the basin, observing, that these supports are sufficiently long to leave about a quarter of an inch between the end of the tube and the orifice in the basin; and let there be a vessel under the basin to catch the water that runs out. As the small pipes discharge more water into the basin than can run out of the central orifice, the water will rise in the basin above the lower end of the pipe, and prevent the air from getting into the vessel, by which the water will cease to flow from the small pipes. But as the water continues to flow from the basin, the air will have liberty again to enter the vessel by the tube, and the water will again flow from the small pipes, and alternately stop and flow, while any water remains in the vessel. As you can guess when the pipes will flow, and when they will stop, you may so manage it, that they will appear to act by word of command. The illuminated Fountain, that plays when the Candles are lighted, and stops when they are extinguished.Fig. 6. Fig. 6. Provide two cylindrical vessels, A B and C D, as in Fig. 6. Connect them by four tubes open at each end, as H I, When the candles are lighted, the air in the upper cover and contiguous pipes will be thereby rarefied, and the jet from the small tube, K, will begin to play: as the air becomes more rarefied, the force of the jet will increase, and it will continue to play till the water in the lower vessel is exhausted. As the motion of the jet is caused by the heat of the candles, when they are extinguished the fountain will stop. A Fountain which acts by the heat of the Sun.Fig. 7. Fig. 7. In the annexed engraving, Fig. 7, G N S is a thin hollow globe of copper, eighteen inches diameter, supported by a small inverted basin, placed on a stand with four legs, A B C D, which have between them, at the bottom, a basin of two feet diameter. Through the leg C passes a concealed pipe, which comes from G, the bottom of the inside of the globe. This pipe goes by H V, and joins the upright pipe u I, to make a jet, as I. The short pipe, u I, which goes to the bottom, has a valve at u, under the horizontal pipe H V, and another valve at T, above that Horizontal pipe, under the cock at K. The use of this cock is to keep the fountain from playing in the day, if you think proper. The north pole N of the globe has a screw that opens a hole, whereby water is poured into the globe. The machine being thus prepared, and the globe half filled with water, put it in an open place, when the heat of the sun rarefying the air as it heats the copper, the air will press strongly against the water, which, coming down the pipe, will lift up the valve at V, and shut the valve at u. The cock being opened, the water will spout out at I, and continue to play a long while, if the sun shines. Inflammable Phosphorus.Take the meal of flour of any vegetable, put it into an iron pan over a moderate fire, and keep it stirring with an iron spoon till it changes to a black powder; to one part of this add four parts of raw alum. Make the whole into a fine powder; put it again into the iron pan, and keep stirring it till it almost catches fire, to prevent its forming into lumps, as it is apt to do when the alum melts; in which case it must be broken again, stirred about, and accurately mixed with the flour, till it emits no more fumes, and the whole appears a fine black powder. Put this powder in a clean dry phial with a narrow neck, filling it to about one-third of the top. Then stop the mouth of the phial with loose paper, so as to let the air pass freely through it, and leave room for the fumes to come through the neck. Place the phial in a crucible, encompassed on all sides with sand, so that it may not touch any part of the crucible, but a considerable space everywhere left between. The phial must be covered up with sand, leaving only a small part bare, by which you can discern whether the powder is ignited. In this state, the crucible is to be surrounded with coals, kindled slowly till it is well heated on all sides, and then the fire is to be raised, till the crucible and every thing in it is red-hot; keep it in this state an hour; after this, the fire still burning as fiercely, close up the orifice of the phial with wax, to exclude the air. Leave it to cool, and you will find in it a black dusty coal formed of the flour and alum. Shake a small quantity of this out of the phial into the cool air, and it will immediately take fire, but will not burn any thing. Keep the bottle dry, as even the air will spoil it effectually. The Magical Mirrors.Make two holes in the wainscot of a room, each a foot high and ten inches wide, and about a foot distant from each Behind the partition, and directly facing each aperture, place two mirrors enclosed in the wainscot, in an angle of forty-five degrees. When a person looks into one of these fictitious mirrors, instead of seeing his own face he will see the object that is in front of the other; thus, if two persons stand at the same time before these mirrors, instead of each seeing himself; they will reciprocally see each other. There should be a sconce with a lighted candle, placed on each side of the two glasses in the wainscot, to enlighten the faces of the persons who look in them, or the experiment will not have so remarkable an effect. To cause a brilliant Explosion under Water.Drop a piece of phosphorus, the size of a pea, into a tumbler of hot water; and, from a bladder furnished with a stop-cock, force a stream of oxygen directly upon it. This will afford a most brilliant combustion under water. Fulminating Mercury.Dissolve 100 grains of mercury by heat, in an ounce and a half of nitric acid. This solution being poured cold upon two measured ounces of alcohol previously introduced into any convenient glass vessel, a moderate heat is to be applied, till effervescence is excited. A white fume then begins to appear on the surface of the liquor, and the powder will be gradually precipitated when the action ceases. The precipitate is to be immediately collected on a filter, well washed with distilled water, and cautiously dried in a heat not exceeding that of a water-bath. Washing the powder immediately is material, because it is liable to the re-action of the nitric acid; and, while any of the acid adheres to it, it is very subject to the action of light. From 100 grains of mercury, about 130 of the powder are obtained. The Iron Tree.Dissolve iron filings in aqua fortis, moderately concentrated, till the acid is saturated; then add to it gradually, a solution of fixed alkali, (commonly called oil of tartar per deliquum.) A strong effervescence will ensue, and the iron, instead of falling to the bottom of the vessel, will afterwards rise so as to cover the 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. To make any Number divisible by Nine, by adding a Figure to it.If (for example) the number named be 72,857, you tell the person who names it to place the number 7 between any two figures of that sum, and it will be divisible by 9; for if any number be multiplied by 9, the sum of the figures of the product will be either 9, or a number divisible by 9. Arithmetical Squares.An arithmetical magical square consists of numbers so disposed in parallel and equal lines, that the sum of each, taken any way of the square, amounts to the same. Any five of these sums taken in a right line make 65. You will observe that five numbers in the diagonals A to D, and B to C, of the magical square, answer to the ranks E to F, and G to H, in the natural square, and that 13 is the centre number of both squares. To form a magical square, first transpose the two ranks in the natural square to the diagonals of the magical square; then place the number 1 under the central number 13, and the number 2 in the next diagonal downward. The number 3 should be placed in the same diagonal line; but as there is no room in the square, you are to place it in that part it would occupy if another square were placed under this. For the same reason, the number 4, by following the diagonal direction, falling out of the square, it is to be put into the part it would hold in another square, placed by the side of this. You then proceed to numbers 5 and 6, still descending; but as the place 6 should hold is already filled, you then go back to the diagonal, and consequently place the 6 in the second place under the 5, so that there may remain an empty space between the two numbers. The same rule is to observed, whenever you find a space already filled. You proceed in this manner to fill all the empty cases in the angle where the 15 is placed: and as there is no space for the 16 in the same diagonal, descending, you must place it in the part it would hold in another square, and continue the same plan till all the spaces are filled. This method will serve equally for all sorts of arithmetical progressions composed of odd numbers; even numbers being too complicated to afford any amusement. To find the Difference between two Numbers, the greatest of which is unknown.Take as many nines as there are figures in the smallest number, and subtract that sum from the number of nines. Let another person add that difference to the largest number, and, taking away the first figure of the amount, add it to the last figure, and that sum will be the difference of the two numbers. For example: Robert, who is 22, tells George, who is older, that he can discover the difference of their ages; he therefore privately deducts 22 from 99, and the difference, which is 77, he tells George to add to his age, and to take away the first figure from the amount, and add it to the last figure, and that last sum will be the difference of their ages. Thus, the difference between
The Boundless Prospect.Take a square box, about six inches long and twelve high, or of any other proportionate dimensions. Cover the inside with four flat pieces of looking-glass placed perpendicular to the bottom of the box. Place at the bottom any objects you please, as a piece of fortification, a castle, tents, soldiers, &c. On the top, place a frame of glass shaped like the bottom of a pyramid, as in Fig. 8, and so formed as to fit on the box like a cover. The four sides of this cover are to be composed of ground glass, or covered inside with gauze, so that the light may enter, and yet the inside be invisible, except at the top, which must be covered with transparent glass: when you look through this glass, the inside will present a pleasing prospect of a boundless extent; and, if managed with care, will afford a deal of amusement. Fig. 8. Fig. 8. To set Fire to a combustible Body by Reflection.Place two concave mirrors at about twelve feet distance from each other, and let the axis of each be 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 The mirror may be either made of glass, metal, or pasteboard gilt. To find the Number of Changes that may be rung on Twelve Bells.Multiply the numbers from 1 to 12 continually into each other, as follow: and the last product will give the number required. 1 To find how many square Yards it would require to write all the Changes of the Twenty-four Letters of the Alphabet, written so small, that each Letter should not occupy more than the hundredth part of a square Inch.By adopting the plan of the preceding article, the changes of the twenty-four letters will be found to be 62,044,840,173,323,943,936,000. Now, the inches in a square yard being 1,296, that number multiplied by 100 gives 129,600, which is the number of letters each square yard will contain; therefore, if we divide the above row of figures, (the number of changes,) by 129,600, the quotient, which is 478,741,050,720,092,160, will be the number of yards required to contain the above mentioned number of changes. But as all the 24 letters are contained in every permutation, it will require a space 24 times as large, viz., 11,849,785,210,282,211,840. Now, as the surface of the whole globe only contains 617,197,435,008,000 square yards, it would require a surface 18,620 times as large as the earth to contain them. The Enchanted Bottle.Fill a glass bottle with water to the beginning of the neck; leave the neck empty, and cork it. Suspend this bottle opposite a concave mirror, and beyond its focus, that it may appear reversed. Place yourself still further distant from the bottle; and instead of the water appearing, as it really is, at the bottom of the bottle, the bottom will be empty, and the water seen at the top. If the bottle be suspended with the neck downwards, it will be reflected in its natural position, and the water at the bottom, although in reality it is inverted, and fills the neck; leaving the bottom vacant. While the bottle is in this position, uncork it, and let the water run gradually out: it will appear, that while the real bottle is emptying, the reflected one is filling. Care must be taken that the bottle is not more than half or three parts full, and that no other liquid is used but water, as in either of these cases the illusion ceases. The Solar Magic Lantern.Make a box, a foot high, eighteen inches wide, and about three inches deep. Two of the opposite sides of this box must be quite open, and in each of the other sides let there be a groove wide enough to admit a stiff paper or pasteboard. You fasten the box against a window, on which the sun's rays fall direct. The rest of the window should be closed up, that no light may enter. Next provide several sheets of stiff paper, blacked on one side. On these papers cut out such figures as your fancy may dictate; place them alternately in the grooves of the box, with their blacked sides towards you, and look at them through a large and clear glass prism; and if the light be strong, they will appear painted with the most lively colours. If you cut on one of these papers the form of a rainbow, about three-quarters of an inch wide, you will have a very good representation of the natural one. For greater convenience, the prism may be placed on a stand on the table, made to turn round on an axis. The Artificial Rainbow.Opposite a window into which the sun shines direct suspend a glass globe, filled with clean water, by means of a string that runs over a pulley, so that the sun's rays may fall on it. Then drawing the globe gradually up, you will observe, when it comes to a certain height, and by placing yourself in a proper situation, a purple colour in the glass; and by drawing it up gradually higher, the other prismatic colours, blue, green, yellow, and red, will successively appear; after which, the colours will disappear, till the globe is raised to about fifty degrees, when they will again appear, but in an inverted order, the red appearing first, and the blue or violet last; on raising the globe a little higher, they will totally vanish. The Æolipiles.The Æolipile is a small hollow globe of brass, or other metal, in which a slender neck or pipe is inserted. This ball, when made red-hot, is cast into a vessel of water, which will rush into its cavity, then almost void of air. If to the necks of two or more of these balls, there be fitted those calls that are used by fowlers and hunters, and the balls placed on the fire, the steam rushing from them will make such a horrible noise, that it will astonish any person who is ignorant of the contrivance. The Talking Busts.Procure two busts of plaster of Paris; place them on pedestals, on the opposite sides of the room. Let a thin tube, of an inch diameter, pass from the ear of one head through the pedestal, under the floor, and go up to the mouth of the other; taking care that the end of the tube that is next the ear of the one head, be considerably larger than that end which comes to the mouth of the other. Now, when a person speaks quite low into the ear of one bust, the sound is reverberated through the length of the tube, and will be distinctly heard by any one placing his ear to the mouth of the other. It is not necessary that the tube should come to the lips of the bust. If there be two tubes, one going to the ear, and the other to the mouth of each head, two persons may converse together, by whispers, without the knowledge of any person who may stand in the middle of the room. The Inanimate Oracle.Place a bust on a pedestal in the corner of a room, and let there be two tubes, as in the preceding article, one to go from the mouth, and the other from the ear, through the pedestal and the floor to an under apartment; there may be also wires, that go from the under jaw and the eyes of the bust, by which they may be easily moved. A person being placed in the room underneath, and applying his ear to one of the tubes at a signal given, will hear any question asked, and can immediately reply, by applying his mouth to the tube which communicates below, at the same time moving the eyes by the wire, to accompany his speech. The Solar Concerto.In a large case, similar to what is used for dials and spring clocks, the front of which, or at least the lower part, must be of glass, covered on the inside with gauze, place a barrel organ, which when wound up is prevented from playing by a catch that takes a toothed wheel at the end of the barrel. To one end of this catch join a wire, at the end of which is a flat circle of cork, of the same dimensions with the inside of a glass tube, in which it is to rise and fall. This tube must communicate with a reservoir that goes across the front part of the bottom of the case, which is to be filled with spirits, such as is used in thermometers. This case being placed in the sun, the spirits will be rarefied by the heat, and, rising in the tube, will lift up the catch or trigger, and set the organ in play; which will continue as long as it is kept in the sun; for the spirits cannot run out of the tube, that part of the catch to which the circle is fixed being prevented from rising beyond a certain point, by a check placed over it. Care must be taken to remove the machine out of the sun before the organ runs down, that its stopping may be evidently affected by the cold. In winter it will perform when placed before the fire. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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