This series of experiments is designed for the use of young people who are interested in the wonders and the beautiful realities of nature, and who delight to observe for themselves how curious are the phenomena revealed by scientific knowledge. Simple instructions are given for the performance of a number of pretty experiments, all of which are perfectly safe, and cost very little money. For "evenings at home," it is hoped that these experiments will be found indefinitely amusing and recreative, at the same time that they will lead the minds of boys and girls to inquiries into the entire fabric of the grand sciences which explains the principles on which they are founded. All the materials spoken of, and all the needful apparatus, which is of the simplest and most inexpensive kind, can be obtained at a good chemist's. It is of the highest importance that all the materials be pure and good.
Obtain a yard of "magnesium tape" or "magnesium wire," sold very cheap by most druggists. Cut a length of six or eight inches; bend one extremity so as to get a good hold of it with a pair of forceps, or even a pair of ordinary scissors, or attach it to the end of a stick or wire. Then hold the piece of magnesium vertically in a strong flame, such as that of a candle, and in a few seconds it will ignite, burning with the splendor of sunshine, and making night seem noonday. As the burning proceeds, a quantity of white powder is formed. This is pure magnesia. While performing this splendid experiment, the room should be darkened.
This is an amusing contrast to the lighting-up by means of magnesium; Again let the room be nearly darkened. Put about a tea-cupful of spirits of wine in a strong common dish or saucer, and place the dish in the middle of the table. Let every one approach to the distance of about a yard. Then ignite the spirit with a match. It will burn with a peculiar yellowish-blue flame, and in the light of this the human countenances, and all objects of similar color, lose their natural tint, and look spectral. The contrast of the wan and ghostly hue with the smiling lips and white teeth of those who look on, is most amusing. The effect of this experiment is heightened by dissolving some common table-salt in the spirit, and still further by putting into it a small quantity of saffron. Let the spirit burn itself away.
The Breath of Life.
Procure a tolerably large bell-glass, such as is used for covering clocks and ornaments upon the mantel-piece. It should not be less than eighteen inches high, and eight or nine inches in diameter. Provide also a common dish, sufficiently large to allow the bell-glass to stand well within its raised border. Then procure two little wax candles, three or four inches in length, and stand each in a little bottle or other temporary candlestick. Place them in the center of the dish and light the wicks. Then pour water into the dish to the depth of nearly an inch, and finish by placing the bell over the candles, which of course are then closely shut in. For a few minutes all goes on properly. The flames burn steadily, and seem to laugh at the idea of their being about to die. But, presently, they become faint,—first one, then the other; the luster and the size of the flames diminish rapidly, and then they go out. This is because the burning candles consumed all the oxygen that was contained within the volume of atmosphere that was in the bell, and were unable, on account of the water, to get new supplies from outside. It illustrates, in the most perfect manner, our own need of constant supplies of good fresh air. The experiment may be improved, or at all events varied, by using candles of different lengths.
Rose-Color Produced from Green.
Obtain a small quantity of roseine,—one of the wonderful products obtained from gas-tar, and employed extensively in producing what are called by manufacturers the "magenta colors." Roseine exists in the shape of minute crystals, resembling those of sugar. They are hard and dry, and of the most brilliant emerald green. Drop five or six of these little crystals into a large glass of limpid water. They will dissolve; but instead of giving a green solution, the product is an exquisite crimson-rose color, the color seeming to trickle from the surface of the water downward. When the solution has proceeded for a short time, stir the water with a glass rod, and the uncolored portion of it will become carmine.
Some Electrical Experiments.
Take a piece of common brown paper, about a foot in length, and half as wide. Hold it before the fire till it becomes quite hot. Then draw it briskly under your left arm several times, so as to rub it on both surfaces against the woolen cloth of your coat. It will now have become so powerfully electrified, that if placed against the papered wall of the parlor, it will hold on for some time, supported, as it were, by nothing.
While the piece of brown paper is thus so strangely clinging to the wall, place a small, light, and fleecy feather against it, and this, in turn, will cling to the paper.
Now, again, make your piece of brown paper hot by the fire, and draw it, as before, several times under the arm. Previously to this, attach a string to one corner, so that it may be held up in the air. Several feathers, of a fleecy kind, may now be placed against each side of the paper, and they will cling to it for several minutes.
Another curious electrical experiment is to take a pane of common glass, make it warm by the fire, then lay it upon two books, allowing only the edges to touch the books, and rub the upper surface with a piece of flannel, or a piece of black silk. Have some bran ready, strew it upon the table under the piece of glass, and the particles will dance.
To Cut a Phial in Half.
Wind round it two bands of paper, corresponding in position to the two temperate zones of the earth, leaving a space between, corresponding to the equatorial zone. Secure the two bands of paper with thread or fine twine. Then wind a long piece of string once around the equatorial space. Let an assistant hold one end of the string, and while holding the other end yourself, move the phial rapidly to and fro, so that the string shall work upon the glass between the two pieces of paper. When the glass becomes hot in the equatorial space, pour some cold water upon it, and the glass will break as evenly as if cut with a knife.
The principle involved in this curious experiment may be applied to the removal of a glass stopper, when too tight in the neck of the bottle for the fingers to stir it. All that is necessary is to wind a piece of thick string round the neck of the bottle, get an assistant to hold one end, and then work the bottle to and fro. The glass of the neck will become so warm as to expand, and the stopper will become loosened. It is often necessary to continue this friction for some minutes before the desired result is attained.
The Invisible rendered Visible.
Place a coin in an empty basin, and let the basin be near the edge of the table. Ask one of the company to stand beside it, and to retire slowly backward until he or she can no longer see the coin. Then pour cold, clear water into the basin, and the person, who the moment before could not perceive the coin, now will see it quite plainly, though without moving a hair's breadth nearer.
Light from Sugar.
In a dark room, rub smartly one against the other, a couple of lumps of white sugar, and light will be evolved. A similar effect is produced by rubbing two lumps of borate of soda one against the other.
Procure a good-sized lump of camphor. Cut it up into pieces of the size of a hazel-nut, and having a large dish filled with cold water in readiness, lay the pieces on the surface, where they will float. Then ignite each one of them with a match, and they will burn furiously, swimming about all the time that the burning is in progress, until at last nothing remains but a thin shell, too wet to be consumed.
Obtain an olive-oil flask, the glass of which must be colorless. In default of an oil-flask, a large test-tube may be employed. Put into it a small quantity of solid iodine (procurable at the chemist's and very cheap), then lightly stop the mouth of the flask or test-tube with some cotton-wool, but not hermetically, and hold it slantwise over the flame of a spirit-lamp. The heat will soon dissolve the iodine, which will next turn into a most beautiful violet-colored vapor, completely filling the glass, and disappearing again as the glass gets cold.
The Two Eggs.
Dissolve as much common table-salt in a pint of water as it will take up, so as to prepare a strong brine. With this brine half fill a tall glass. Then pour in pure water, very carefully. Pour it down the side, or put it in with the help of a spoon, so as to break the fall. The pure water will then float upon the top of the brine, yet no difference will be visible. Next, take another glass of exactly the same kind, and fill it with pure water. Now take a common egg, and put it into the vessel of pure water, when it will instantly sink to the bottom. Put another egg into the first glass, and it will not descend below the surface of the brine, seeming to be miraculously suspended in the middle. Of course the two glass vessels should be considerably wider than the egg is long.
The Magic Aperture.
Put several lighted candles upon the table, in a straight row and near together. Lay upon the table, in front of them, a large piece of smooth, white paper. Have ready a piece of pasteboard, large enough to conceal the candles, with a small hole cut in it above the middle. Place this so as to stand upon its edge between the row of candles and the sheet of paper in front, and there will be as many images of flames thrown through the hole and upon the paper as there are burning candles.
Obtain some boracic acid, mix it well with a small quantity of spirits of wine, or alcohol, place the alcohol in a saucer upon a dish, and then ignite it with a match. The flame will be a beautiful green. To see the color to perfection, of course, the room should be somewhat darkened.
A green flame may also be produced by using chloride of copper instead of boracic acid. And instead of mixing it with the alcohol, a small quantity may be imbedded in the wick of a candle.
A Beautiful Imitation of Hoar Frost.
Obtain a large bell-glass, with a short neck and cork at the top, such as may be seen in the chemists' shops. Then procure a small quantity of benzoic acid, which exists in the shape of snowy crystals. Elevate the bell-glass upon a little stage made of books or pieces of wood, so as to allow a spirit-lamp to be introduced underneath, and a little evaporating dish to be held above the flame by means of a ring of wire with suitable handle. Place the benzoic acid in the evaporating dish, over the flame, and presently the acid will ascend in vapor and fill the bell, which must not be quite closed at the top. Before setting up the apparatus, introduce into the bell a small branch of foliage, which may be hung by a thread from the neck of the bell. The stiffer and more delicate this branch, the better. In a short time, it will become covered with a soft white deposit of the acid, very closely resembling hoar-frost. This makes an extremely pretty ornament for the parlor.
To Boil Water Without Fire.
Half fill a common oil-flask with water, and boil it for a few minutes over the flame of a spirit-lamp. While boiling, cork up the mouth of the flask as quickly as you can, and tie a bit of wet bladder over the cork, so as to exclude the air perfectly. The flask being now removed from the lamp, the boiling ceases. Pour some cold water upon the upper portion of the flask, and the ebullition recommences! Apply hot water, and it stops! And thus you may go on as long as you please.
to Convert a Liquid into a Solid.
Dissolve about half a pound of sulphate of soda in a pint of boiling water, and after it has stood a few minutes to settle, pour it off into a clean glass vessel. Pour a little sweet oil upon the surface, and put it to stand where it can get cold, and where no one will touch it. When cold, put in a stick, and the fluid, previously clear, will at once become opaque, and begin to crystallize, until at length there is a solid crystalline mass.
Ice on Fire.
Make a hole in a block of ice with a hot poker. Pour out the water, and fill up the cavity with camphorated spirits of wine. Then ignite the spirit with a match, and the lump of ice will seem to be in flames.
Experiments Requiring Chemical Solutions.
To prepare these solutions, purchase of a druggist a small quantity of the solid crystals of the substance needed for the experiment you wish to try. Dissolve the crystals in clear pure water, and keep the solution in a little bottle, labeled with the name. It is seldom that the solutions need be strong. When the crystal is a colored one, enough should be used to give the water a light tint, blue, yellow, or what it may be. None of these solutions will do any harm to the hands, unless there is a cut or a wound of any kind upon the skin. It is well also, not to let a drop of any of them fall upon the clothes, or upon furniture, for some of them will stain. And none of them should ever be tasted, or touched by the lips or tongue, many of them being acrid and even poisonous.
With the acids still greater care is needed, the stronger acids being corrosive and poisonous. The greater portion of these substances must likewise not be smelled, as the fumes or vapors would affect the nostrils painfully.
For the proper performance of these experiments with solutions, etc.,—at all events for the neatest and most elegant performance of them,—there should be obtained from the chemist's shop about a dozen test-tubes. These are little glass vessels, manufactured on purpose, and very cheap. Do not take glasses that may afterward be used for drinking or household purposes. Be careful to have every one of your experiment glasses perfectly clean.
To produce a Beautiful Violet-Purple Color.
Take a nearly colorless solution of any salt of copper. The sulphate is the cheapest and handiest. Fill the test-tube or other experimenting-glass about two-thirds full. Then drop in, slowly, a little liquid ammonia. It will cause a beautiful blue to appear, and presently a most lovely violet-purple, which, by stirring with a glass rod, extends all through the fluid.
If now you drop into this a very little nitric acid, the fluid will again become as clear as pure water.
To Make a Splendid Scarlet.
Again take some solution of sulphate of copper. Add to it a little solution of bichromate of potash. Then add a little solution of nitrate of silver, and there is produced a splendid scarlet color.
To Make a Deep Blue.
Now, take a nearly colorless solution of sulphate of iron, and drop into it, slowly, a small quantity of solution of yellow prussiate of potash. This will induce a beautiful deep blue, quite different from the blues that are produced from copper salts.
To Make a Yellow Color.
Take a solution of acetate of lead, and add a few drops of solution of iodide of potassium, and a most lovely canary-yellow color is produced.
Nearly all those experiments which result in the production of color may be performed in another way, and be then applied to the purposes of secret writing. Thus:
Write with dilute solution of sulphate of copper. The writing will be quite invisible, but become blue when held over the vapor of liquid ammonia.
Write with the same solution, and wash the paper with solution of yellow prussiate of potash, and the writing, previously invisible, will become brown. If you choose you may reverse this method, writing with solution of the prussiate of potash, and washing the paper with solution of the copper salt.
Write with solution of sulphate of iron, and the writing will again be invisible. Wash it over with tincture of galls, and it becomes black.
Write with sulphate of iron, and use a wash of yellow prussiate of potash, and the writing will come out blue. This experiment may likewise be reversed, and with similar result.
How to Copper a Knife-Blade.
Make a rather strong solution of sulphate of copper. Let a clean and polished piece of steel or iron, such as the blade of a knife, stand in it for a few minutes, and the iron will become covered or encrusted with a deposit of pure copper.
To Make Beautiful Crystals.
Dissolve, in different vessels, half an ounce each of the sulphates of iron, zinc, copper, soda, alumina, magnesia, and potash. The solutions can be made more rapidly by using warm water. When the salts are all completely dissolved, pour the whole seven solutions into a large dish, stir the mixture with a glass rod, then place it in a warm place, where it will not be disturbed. By degrees, the water will evaporate, and then the salts will re-crystallize, each kind preserving its own proper form and color. Some occur in groups, some as single crystals. If carefully protected from dust, these form extremely pretty ornaments for the parlor.
These may be prepared by dissolving alum in water in such quantity that at last the water can take up no more, and the undissolved alum lies at the bottom of the vessel. The solution thus obtained is called a saturated one. Then procure a common ornamental wire basket, and suspend it in the solution, so as to be well covered in every part. There should be twice as much solution as will cover the basket. The wires of the basket should be wound with worsted, so that the surface may be rough. Leave it undisturbed in the solution, and gradually the crystals will form all over the surface. Before putting in the basket, it is best to further strengthen the solution by boiling it down to one half, after which it should be strained.
Dissolve half an ounce of acetate of lead in six ounces of water. The solution will be turbid, so clarify it with a few drops of acetic acid. Now put the solution into a clean phial, nearly filling the phial. Suspend in the solution, by means of a thread attached to the cork, a piece of clean zinc wire. By degrees, the wire will become covered with beautiful metallic spangles, like the foliage of a tree.