Combustion without flame may be shown in a very elegant and agreeable manner, by making a coil of platinum wire by twisting it round the stem of a tobacco pipe, or any cylindrical body, for a dozen times or so, leaving about an inch straight, which should be inserted into the wick of a spirit lamp; light the lamp, and after it has burned for a minute or two, extinguish the flame quickly; the wire will soon become red hot, and, if kept from draughts of air, will continue to burn until all the spirit is consumed. Spongy platinum, as it is called, answers rather better than wire, and has been employed in the formation of fumigators for the drawing-room, in which, instead of pure spirit, some perfume, such as lavender water, is used; by its combustion an agreeable odor is diffused through the apartment. These little lamps were much in vogue a few years ago, but are now nearly out of fashion.
Experiments on combustion might be multiplied, almost to any amount, but the above will be sufficient for our purpose.
POTASSIUM.
Potassium was discovered by Sir H. Davy, in the beginning of the present century, while acting upon potash with the enormous galvanic battery of the Royal Institution, consisting of two thousand pairs of four inch plates. It is a brilliant white metal, so soft as to be easily cut with a penknife, and so light as to swim upon water, on which it acts with great energy, uniting with the oxygen, and liberating the hydrogen, which takes fire as it escapes.
EXPERIMENT.
Trace some continuous lines on paper with a camel's-hair brush, dipped in water, and place a piece of potassium about the size of a pea, on one of the lines, and it will follow the course of the pencil, taking fire as it runs, and burning with a purplish light. The paper will be found covered with a solution of ordinary potash. If turmeric paper be used, the course of the potassium will be marked with a deep brown color. Corollary: hence, if you touch potassium withwetfingers, you will burn them!
If a small piece of the metal be placed on a piece of ice, it will instantly take fire, and form a deep hole, which will be found to contain a solution of potash.
In consequence of its great affinity for oxygen, potassium must be kept in some fluid destitute of it, such as naphtha.
Saltpeter, or niter, is a compound of this metal (or rather its oxide) with nitric acid. It is one of the ingredients of gunpowder, and has the property of quickening the combustion of all combustible bodies.
EXPERIMENT.
Rub together in awarmmortar, three parts of powdered niter, two of dry carbonate of potash, and one of flour of brimstone; place a small quantity of the mixture in an iron ladle, and heat it over the fire, when it will speedily melt, and then explode with a very loud noise; and if held under a foul chimney, will save the expense of a chimney sweep: but avoid cooking time.
Another salt of potash remarkable for the same property, in even a greater degree, is thechlorateof potash.
EXPERIMENTS.
1. Triturate together in adrymortar a few grains of flowers of sulphur, with a small quantity of the chlorate of potash, and a succession of sharp explosions, like the crack of a whip, will be produced.
2. Substitute half a grain of phosphorus for the sulphur, and the action will be much more violent. The hand should be defended by a thick glove, and the eyes carefully guarded, in making this experiment.
3. Mix very carefully a little of this salt, reduced to powder, with a little lump sugar, also powdered, and drop on the mixture a little strong sulphuric acid, and it will instantly burst into a flame. This experiment also requires caution.
Want of space precludes us from considering the individual metals and their compounds in detail; it must suffice to describe some experiments, showing some of their properties.
The different affinities of the metals for oxygen, may be exhibited in various ways. The silver or zinc tree has already been described.
EXPERIMENTS.
1. Into a solution of nitrate of silver, in distilled water, immerse a clean plate or slip of copper. The solution, which was colorless, will soon begin to assume a greenish tint, and the piece of copper will be covered with a coating of a light gray color, which is the silver formerly united to the nitricacid, which has been displaced by the greater affinity orlikingof the oxygen and acid for the copper.
2. When the copper is no longer coated, but remains clean and bright when immersed in the fluid, all the silver has been deposited, and the glass now contains a solution ofcopper.
Place a piece of clean iron in the solution, and it will almost instantly be coated with a film ofcopper, and this will continue until the whole of that metal is removed, and its place filled by an equivalent quantity ofiron, so that nitrate ofironis found in the liquid. The oxygen and nitric acid remain unaltered in quantity or quality during these changes, being merely transferred from one metal to another.
A piece of zinc will displace the iron in like manner, leaving a solution of nitrate of zinc.
Nearly all the colors used in the arts, are produced by metals and their combinations; indeed, one is namedchromium, from a Greek word signifying color, on account of the beautiful tints obtained from its various combinations with oxygen and the other metals. All the various tints of green, orange, yellow, and red, are obtained from this metal.
Solutions of most of the metallic salts give precipitates with solutions of alkalies and their salts, as well as with many other substances, such as what are usually called prussiate of potash, hydro-sulphuret of ammonia, &c.; and the colors differ according to the metal employed; and so small a quantity is required to produce the color, that the solutions before mixing may be nearly colorless.
EXPERIMENTS.
1. To a solution of sulphate of iron, add a drop or two of a solution of prussiate of potash, and a blue color will be produced.
2. Substitute sulphate of copper for iron, and the color will be a rich brown.
3. Another blue, of quite a different tint, may be produced by letting a few drops of a solution of ammonia fall into one of sulphate of copper, when a precipitate of a light blue falls down, which is dissolved by an additional quantity of the ammonia, and forms a transparent solution of the most splendid rich blue color.
4. Into a solution of sulphate of iron, drop a few drops of a strong infusion of galls, and the color will become a bluish-black—infact,ink. A littleteawill answer as well as the infusion of galls. This is the reason why certain stuffs formerly in general use for dressing gowns for gentlemen were so objectionable; for as they were indebted to a salt of iron for their color, buff, as it was called, a drop of tea accidentally spilled, produced all the effect of a drop of ink.
5. Put into a largish test tube, two or three small pieces of granulated zinc, fill it about one third full of water, put in a few grains of iodine, and boil the water, which will at first acquire a dark purple color, gradually fading as the iodine combines with the zinc. Add a little more iodine from time to time, until the zinc is nearly all dissolved. If a few drops of this solution be added to an equally colorless solution of corrosive sublimate (a salt of mercury), a precipitate will take place of a splendid scarlet color, brighter, if possible, than vermilion, which is also a preparation of mercury.
CRYSTALLIZATION OF METALS.
Some of the metals assume certain definite forms in return from the fluid to the solid state. Bismuth shows this property more readily than most others.
EXPERIMENT.
Melt a pound or two of bismuth in an iron ladle over the fire; remove it as soon as the whole is fluid; and when the surface has become solid break a hole in it, and pour out the still fluid metal from the interior; what remains will exhibit beautifully-formed crystals of a cubic shape.
Sulphur may be crystallized in the same manner, but its fumes, when heated, are so very unpleasant, that few would wish to encounter them.
One of the most remarkable facts in chemistry—a science abounding in wonders—is the circumstance that the mere contact of hydrogen, thelightestbody known, with the metal platinum, the heaviest, when in a state of minute division, called spongy platinum, produces an intense heat, sufficient to inflame the hydrogen: of course this experiment must be made in the presence of atmospheric air or oxygen. If a small piece of the metal in the state above named be introduced into a mixture of oxygen and hydrogen, it will cause them to explode. A very small quantity of gas should be employed, and placed in a jar lightly covered with a card, or the explosion would be dangerous.
BEAUTIES OF CRYSTALLIZATION.
Dissolve alum in hot water until no more can be dissolved in it; place in it a smooth glass rod and a stick of the same size; next day, the stick will be found covered with crystals, but the glass rod will be free from them: in this case, the crystals cling to the rough surface of the stick, but have no hold upon the smooth surface of the glass rod. But if the rod be roughened with a file at certain intervals, and then placed in the alum and water, the crystals will adhere to the rough surfaces, and leavethemsmooth bright and clear.
Tie some threads of lamp-cotton irregularly around a copper wire or glass rod; place it in a hot solution of blue vitriol, strong as above, and the threads will be covered with beautiful blue crystals, while the glass rod will be bare.
Bore a hole through a piece of coke, and suspend it by a string from a stick, placed across a hot solution of alum; it will float; but, as it becomes loaded with crystals, it will sink in the solution according to the length of the string. Gas-coke has mostly a smooth, shining, and almost metallic surface, which the crystals will avoid, while they will cling only to the most irregular and porous parts.
If powdered turmeric be added to the hot solution of alum, the crystals will be of a bright yellow; litmus will cause them to be of a bright red; logwood will yield purple; and common writing ink, black; and the more muddy the solution, the finer will be the crystals.
To keep colored alum crystals from breaking or losing their color, place them under a glass shade with a saucer of water; this will preserve the atmosphere moist, and prevent the crystals getting too dry.
If crystals be formed on wire, they will be liable to break off, from the expansion and contraction of the wire by changes of temperature.
TO CRYSTALLIZE CAMPHOR.
Dissolve camphor in spirit of wine, moderately heated, until the spirit will not dissolve any more; pour some of the solution into a cold glass, and the camphor will instantly crystallize in beautiful tree-like forms, such as we see in the show-glasses of camphor in druggists' windows.
CRYSTALLIZED TIN.
Mix half an ounce of nitric acid, six drams of muriatic acid, and two ounces of water; pour the mixture upon a piece of tin plate previously made hot, and after washing it in the mixture it will bear a beautiful crystalline surface, in feathery forms. This is the celebratedmoirée métallique, and, when varnished, is made into ornamental boxes, &c. The figures will vary according to the degree of heat previously given to the metal.
CRYSTALS IN HARD WATER.
Hold in a wine-glass of hard water a crystal of oxalic acid, and white threads,i. e.oxalate of lime, will instantly descend through the liquid suspended from the crystal.
VARIETIES OF CRYSTALS.
Make distinct solutions of common salt, niter, and alum; set them in three saucers in any warm place, and let part of the water dry away or evaporate; then remove them to a warm room. The particles of the salts in eachsaucerwill begin to attract each other, and form crystals, but not all of the same figure: the common salt will yield crystals with six square and equal faces, or sides; the niter six-sided crystals; and the alum, eight-sided crystals; and if these crystals be dissolved over and over again, they will always appear in the same forms.
A LIQUID CHANGED TO A SOLID, AND HEAT FROM CRYSTALLIZATION.
A strong saline solution excluded from theairwill frequently crystallize the instant that air is admitted. For this purpose make a solution of Glauber's salt (sulphate of soda) in boiling water (3 lbs. of the salt to 2 lbs. of water); bottle and cork quickly; also tie over the neck a piece of wet bladder. When perfectly cold, or even a few days afterwards, remove the cork, and the salt will immediately crystallize, shooting out the most beautiful crystals, at last becoming nearly solid: at the same time the whole becomes warm, in consequence of the latent heat generated by the change of the liquid to the solid state. If the liquid will not crystallize quickly on removing the cork, tie a crystal of Glauber's salt to a bit of wire, touch the surface ofthe liquid, and the crystallization will then generally occur.
ANOTHER EXPERIMENT.
Heat some blue vitriol (sulphate of copper) in an iron ladle till all the water contained in the crystals is driven off, and the color changes to a gray. Take the lumps out without breaking them, and lay the dried blue vitriol on a plate; if this be moistened with water, steam is produced; and if a slice of phosphorus is then laid on the sulphate of copper, it ignites, demonstrating again that the condensation of a liquid produces heat. The addition of the water restores the blue color, thus proving that water was necessary to the composition of blue vitriol.
A SOLID CHANGED TO A LIQUID, AND INTENSE COLD FROM THE LIQUEFACTION.
Mix five parts by weight of powdered muriate of ammonia, commonly termed sal ammoniac, five parts of niter in powder, and sixteen parts of water. A temperature of twenty-two degrees below the freezing point of water is produced; and if a phial of water, or any convenient metallic cylinder containing water, be surrounded with a sufficient quantity of the freezing mixture, ice is obtained. The ice clings to the interior of the tube, but may easily be removed by dipping it in tepid water.
This experiment is the reverse of the last, and proves that a sudden reduction of a solid to the liquid condition always affords cold.
An amusing combination of two experiments may be made by putting some fresh-burned lime into one tea-pot and this freezing mixture into another. When water is poured on the one containing lime, it gives out steam from the spout; while the addition of water to the other produces so much cold, that it can hardly be kept in the hand. Thus heat and cold are afforded by the same medium, water.
MAGIC OF HEAT.
Melt a small quantity of the sulphate of potassa and copper in a spoon over a spirit lamp; it will be fused at a heat just below redness, and produce a liquid of a dark green color. Remove the spoon from the flame, when the liquidwill become a solid of a brilliant emerald green color, and so remain till its heat sinks nearly to that of boiling water; when suddenly a commotion will take place throughout the mass, beginning from the surface, and each atom, as if animated, will start up and separate itself from the rest, till, in a few moments, the whole will become a heap of powder.
SUBLIMATION BY HEAT.
Provide two small pieces of glass; sprinkle a minute portion of sulphur upon one piece, lay thin slips of wood around it, and place upon it the other piece of glass. Move them slowly over the flame of a lamp or candle, and the sulphur will become sublimed, and form gray nebulous patches, which are very curious microscopic objects. Each cluster consists of thousands of transparent globules, imitating in miniature the nebulæ which we see figured in treatises on astronomy. By observing the largest particles, we shall find them to be flattened on one side. Being very transparent, each of them acts the part of a little lens, and forms in its focus the image of a distant light, which can be perceived even in the smaller globules, until it vanishes from minuteness. If they are examined again after a certain number of hours, the smaller globules will generally be found to have retained their transparency, while the larger ones will have become opaque, in consequence of the sulphur having undergone some internal spontaneous change. But the most remarkable circumstance attending this experiment is, that the globules are found adhering to the upper glass only; the reason of which is, that the upper glass is somewhat cooler than the lower one: by which means we see that the vapor of sulphur is very powerfully repelled by heated glass. The flattened form of the particles is owing to the force with which they endeavor to recede from the lower glass, and their consequent pressure against the surface of the upper one. This experiment is considered by its originator, Mr. H. F. Talbot, F.R.S., England, to be a satisfactory argument in favor of the repulsive power of heat.
HEAT PASSING THROUGH GLASS.
The following experiment is also by Mr. Talbot: Heat a poker bright red hot, and having opened a window, apply the poker quickly very near to the outside of a pane, andthe hand to the inside; a strong heat will be felt at the instant, which will cease as soon as the poker is withdrawn, and may be again renewed, and made to cease as quickly as before. Now, it is well known that if a piece of glass be so much warmed as to convey the impression of heat to the hand, it will retain some part of that heat for a minute or more; but in this experiment the heat will vanish in a moment. It will not, therefore, be the heated pane of glass that we shall feel, but heat which has come through the glass, in a free or radiant state.
METALS UNEQUALLY INFLUENCED BY HEAT.
All metals do not conduct heat at the same rate, as may be proved by holding in the flame of a candle at the same time, a piece of silver wire and a piece of platina wire, when the silver wire will become too hot to hold, much sooner than the platina. Or, cut a cone of each wire, tip it with wax, and place it upon a heated plate, (as a fire-shovel,) when the wax will melt at different periods.
SPONTANEOUS COMBUSTION.
Mix a small quantity of chlorate of potassa with spirit of wine in a strong saucer; add a little sulphuric acid, and an orange vapor will arise and burst into flame with a loud crackling sound.
INEQUALITY OF HEAT IN FIRE-IRONS.
Place before a brisk fire a set of polished fire-irons, and beside them a rough unpolished poker, such as is used in a kitchen, instead of a bright poker. The polished irons will remain for a long time without becoming warmer than the temperature of the room, because the heat radiated from the fire is all reflected, or thrown off, by the polished surface of the irons, and none of it is absorbed. The rough poker will, however, become speedily hot, so as not to be used without inconvenience. Hence, the polish of fire-irons is not merely ornamental, but useful.
EXPANSION OF METAL BY HEAT.
Provide an iron rod, and fit it exactly into a metal ring: heat the rod red hot, and it will no longer enter the ring.
Observe an iron gate on a warm day, when it will shut with difficulty; whereas it will shut loosely and easily on a cold day.
EVAPORATION OF A METAL.
Rub a globule of mercury upon a silver spoon, and the two metals will combine with a white appearance; heat the spoon carefully in the flame of a spirit lamp, when the mercury will volatilize and disappear, and the spoon may then be polished until it recovers its usual luster: if, however, the mercury be left for some time on the spoon, the solid texture of the silver will be destroyed throughout, and then the silver can only be recovered by heating it in a ladle. Care must be taken to avoid the fumes of mercury, which are very poisonous.
A FLOATING METAL ON FIRE.
Throw a small piece of that marvelous substance, potassium, into a basin of water, and it will swim upon the surface and burn with a beautiful light, of a red color mixed with violet. When moderately heated in the air, potassium takes fire, and burns with a red light.
ICE MELTED BY AIR.
If two pieces of ice be placed in a warm room, one of them may be made to melt much sooner than the other, by blowing on it with a pair of bellows.
SPLENDID SUBLIMATION.
Put into a flask a small portion of iodine; hold the flask over the flame of a spirit-lamp, and from the state of bluish-black crystals, the iodine, on being heated, will become a violet-colored transparent gas; but, in cooling, will resume its crystalline form.
MAGIC INKS.
Dissolve oxide of cobalt in acetic acid, to which add a little niter: write with this solution; hold the writing to the fire, and it will be of pale rose color, which will disappear on cooling.
Dissolve equal parts of sulphate of copper and muriate of ammonia in water; write with the solution, and it will give a yellow color when heated, which will disappear when cold.
Dissolve nitrate of bismuth in water; write with the solution, and the characters will be invisible when dry, but will become legible on immersion in water.
Dissolve, in water, muriate of cobalt, which is of abluish-green colour, and the solution will be pink; write with it, and the characters will be scarcely visible: but, if gently heated, they will appear in brilliant green, which will disappear as the paper cools.
Dissolve in water a few grains of prussiate of potash; write with this liquid, which is invisible when dry; wash over with a dilute solution of iron, made by dissolving a nail in a little aqua fortis; a blue and legible writing is immediately apparent.[4]
CHAMELEON LIQUIDS.
Put a small portion of the compound called mineral chameleon into several glasses, pour upon each water at different temperatures, and the contents of each glass will exhibit a different shade of color. A very hot solution will be of a beautiful green color; a cold one, a deep purple.
Make a colorless solution of sulphate of copper; add to it a little ammonia, equally colorless, and the mixture will be of an intense blue color; add to it a little sulphuric acid, and the blue color will disappear; pour in a little solution of caustic ammonia, and the blue color will be restored. Thus may the liquor be changed at pleasure.
THE MAGIC DYES.
Dissolve indigo in diluted sulphuric acid, and add to it an equal quantity of solution of carbonate of potassa. If a piece of white cloth be dipped in the mixture, it will be changed to blue; yellow cloth, in the same mixture, may be changed to green; red to purple; and blue litmus paper to red.
Nearly fill a wine-glass with the juice of beet-root, which is of a deep red color; add a little lime-water, and the mixture will be colorless; dip into it a piece of white cloth, dry it rapidly, and in a few hours the cloth will become red.
WINE CHANGED INTO WATER.
Mix a little solution of subacetate of lead with port wine; filter the mixture through blotting-paper, and a colorless liquid will pass through; to this add a small quantity of dry salt of tartar; distil in a retort, when a spirit will arise, which may be inflamed.
TWO COLORLESS TRANSPARENT LIQUIDS BECOME BLACK AND OPAQUE.
Have in one vessel some dilute hydrosulphate of ammonia, and in another a solution of acetate of lead; they are both colorless and transparent; mix them, and they will become black and opaque.
TWO COLORLESS FLUIDS MAKE A COLORED ONE.
Put into a wine-glass of water a few drops of prussiate of potash, and into a second glass of water a little weak solution of sulphate of iron in water; pour the colorless mixtures together into a tumbler, and they will be immediately changed to a bright deep blue.
Or, mix the solution of prussiate of potash with that of nitrate of bismuth, and a yellow will be the product.
Or, mix the solution of prussiate of potash with that of sulphate of copper, and the mixture will be of a reddish-brown color.
CHANGE OF COLOR BY COLORLESS FLUIDS.
Three different colors may be produced from the same infusion, merely by the addition of three colorless fluids. Slice a little red cabbage, pour boiling water upon it, and when cold decant the clear infusion, which divide into three wine-glasses: to one, add a small quantity of solution of alum in water; to the second, a little solution of potash in water; and to the third, a few drops of muriatic acid. The liquor in the first glass will assume a purple color, the second a bright green, and the third a rich crimson.
TO CHANGE A BLUE LIQUID TO WHITE.
Dissolve a small lump of indigo in sulphuric acid by the aid of moderate heat, and you will obtain an intense blue color; add a drop of this to half a pint of water, so as to dilute the blue; then pour some of it into strong chloride of lime, and the blue will be bleached with almost magical velocity.
VERITABLE "BLACK" TEA.
Make a cup of strong green tea; dissolve a little green copperas in water, which add to the tea, and its color will be black.
RESTORATION OF COLOR BY WATER.
Water being a colorless fluid, ought, one would imagine, when mixed with other substances of no decided color, to produce a colorless compound. Nevertheless, it is to water only that blue vitriol, or sulphate of copper, owes its vivid blueness, as will be plainly evinced by the following simple experiment. Heat a few crystals of the vitriol in a fire-shovel, pulverize them, and the powder will be of a dull and dirty whiteappearance. Pour a little water upon this, when a slight hissing noise will be heard, and at the same moment the blue color will instantly reappear.
Under the microscope the beauty of this experiment will be increased, for the instant that a drop of water is placed in contact with the vitriol, the powder may be seen to shoot into blue prisms. If a crystal of prussiate of potash be similarly heated, its yellow color will vanish, but reappear on being dropped into water.
[5]TWO LIQUIDS MAKE A SOLID.
Dissolve muriate of lime in water until it will dissolve no more; measure out an equal quantity of oil of vitriol; both will be transparent fluids; but if equal quantities of each be slowly mixed and stirred together, they will become a solid mass, with the evolution of smoke or fumes of muriatic acid.
TWO SOLIDS MAKE A LIQUID.
Rub together in a mortar, equal quantities of the crystals of Glauber salts and nitrate of ammonia, and the two salts will slowly become a liquid.
A SOLID OPAQUE MASS MAKES A TRANSPARENT LIQUID.
Take the solid mixture of the solutions of muriate of lime and carbonate of potash, pour upon it a very little nitric acid, and the solid opaque mass will be changed to a transparent liquid.
TWO COLD LIQUIDS MAKE A HOT ONE.
Mix four drams of sulphuric acid (oil of vitriol) with one dram of cold water, suddenly, in a cup, and the mixture will be nearly half as hot again as boiling water.
QUINTUPLE TRANSMUTATION.
Take five ale-glasses: place into the first a solution of iodide of potassium; into the second, a solution of corrosive sublimate, sufficiently strong to yield a scarlet precipitate with the iodide in the first glass, without redissolving, as the effect of the experiment depends on the adjustment of this beforehand; into the third, a strong solution of iodide of potassium with some oxalate of ammonia; into the fourth, a solution of muriate of lime; into the fifth, a solution of hydrosulphate of ammonia. The following changes occur.
No. 1 added to No. 2 produces a yellow, quickly changing to a scarlet; No. 2, poured into No. 3, becomes clear and transparent again; No. 3, into No. 4, changes a milky white; No. 4, poured into No. 5, produces a black precipitate.
Thus, a clear and colorless liquid is changed to scarlet; the scarlet again becomes colorless; the colorless liquid, milky white; and the white, black.
THE SAME AGENT MAY PRODUCE AND DESTROY COLOR.
Procure a bottle of chlorine, and arrange two tall cylindrical glasses: fill one half full with a dilute solution of iodide of potassium and starch, and the other with a very dilute solution of sulphate of indigo; provide each vessel with a plate glass or cardboard valve, laid on the top; carefully open the bottle of chlorine, invert it slowly over one cylindrical vessel, so as to pour out half the gas, which is very heavy; add the remainder to the other, and shake up both vessels. The chlorine will bleach the indigo, and afford a magnificent purple in the iodide of potassium and starch, because it sets free iodine, which combines with the starch, producing a purple compound.
UNION OF TWO METALS WITHOUT HEAT.
Cut a circular piece of gold leaf, called "dentists' gold," about half an inch in diameter; drop upon it a globule of mercury, about the size of a small pea, and if they be left for a short time, the gold will lose its solidity and yellow color, and the mercury its liquid form, making a soft mass of the color of mercury.
MAGIC BREATH.
Half fill a glass tumbler with lime-water; breathe into it frequently, at the same time stirring it with a piece ofglass. The fluid, which before was perfectly transparent, will presently become quite white, and if allowed to remain at rest, real chalk will be deposited.
TWO BITTERS MAKE A SWEET.
It has been discovered, that a mixture of nitrate of silver with hyposulphate of soda, both of which are remarkably bitter, will produce the sweetest known substance.
VISIBLE AND INVISIBLE.
Write with French chalk on a looking-glass; wipe it with a handkerchief, and the lineswilldisappear; breathe on it, and they will reappear. This alternation will take place for a great number of times, and after the lapse of a considerable period.
TO FORM A LIQUID FROM TWO SOLIDS.
Rub together in a Wedgewood mortar a small quantity of sulphate of soda and acetate of lead, and as they mix they will become liquid.
Carbonate of ammonia and sulphate of copper, previously reduced to powder separately, will also, when mixed, become liquid, and acquire a most splendid blue color.
The greater number of salts have a tendency to assume regular forms, or becomecrystallized, when passing from the fluid to the solid state; and the size and regularity of the crystals depends in a great measure on the slow or rapid escape of the fluid in which they were dissolved. Sugar is a capital example of this property; the ordinary loaf-sugar being rapidly boiled down, as it is called: while to make rock-candy, which is nothing but sugar in a crystallized form, the solution is allowed to evaporate slowly, and as it cools it forms into those beautiful crystals termed rock-candy. The threads found in the center of some of the crystals are merely placed for the purpose of hastening the formation of the crystals.
EXPERIMENTNO. 1.—Make a strong solution of alum, or of sulphate of copper, or blue vitriol, and place in them rough and irregular pieces of clinker from stoves, or wire baskets, and set them by in a cool place, where they will be free from dust, and in a few days crystals of the several salts will deposit themselves on the baskets, &c. They should then be taken out of the solutions, and dried in an oven not too hot, when they form very pretty ornaments for a room.
EXPERIMENTNO. 2.—Fill a Florence flask up to the neck with a strong solution of sulphate of soda, or Glauber salt, boil it, and tie the mouth over with a piece of moistened bladder while boiling, and set it by in a place where it cannot be disturbed. After twenty-four hours it will probably still remain fluid. Pierce the bladder covering with a penknife, and the percussion of the air will cause the whole mass instantly to crystallize, and the flask will become quite warm from the latent caloric, of which we have spoken before, given out by the salt in passing from the fluid to the solid state. It is better to prepare two or three flasks at the same time, to provide against accidents, for the least shake will often cause the crystallization to take place before the proper time.
THE SPECTRAL LAMP.
Mix some common salt with spirit of wine in a platinum or metallic cup; set the cup upon a wire frame over a spirit-lamp, which should be inclosed on each side, or in a dark-lantern: when the cup becomes heated, and the spirit ignited, it will burn with a strong yellow flame: if, however, it should not be perfectly yellow, throw more salt into the cup. The lamp being thus prepared, all other lights should be extinguished, and the yellow lamp introduced, when an appalling change will be exhibited; all the objects in the room but of one color, and the complexions of the several persons, whether old or young, fair or brunette, will be metamorphosed to a ghastly, death-like yellow; whilst the gayest dresses, as the brightest crimson, the choicest lilac, the most vivid blue or green—all will be changed into one monotonous yellow: each person will be inclined to laugh at his neighbor, himself insensible of being one of the spectral company.
Their astonishment may be heightened by removing the yellow light to one end of the room, and restoring the usual or white light at the other; when one side of each person's dress will resume its original color, while the other will remain yellow; one cheek may bear the bloom of health, and the other, the yellow of jaundice. Or if, when the yellow light only is burning, the white light be introduced within a wire sieve, the company and the objects in the apartment will appear yellow, mottled with white.
Red light may be produced by mixing with the spirit inthe cup over the lamp, salt ofstrontiuminstead of common salt; and the effect of the white or yellow lights, if introduced through a sieve upon the red light, will be even more striking than the white upon the yellow light.
CURIOUS CHANGE OF COLORS.
Let there be no other light than a taper in the room; then put on a pair of dark green spectacles, and having closed one eye, view the taper with the other. Suddenly remove the spectacles, and the taper will assume a bright red appearance; but if the spectacles be instantly replaced, the eye will be unable to distinguish anything for a second or two. The order of colors will, therefore, be as follows: green, red, green, black.
THE PROTEAN LIGHT.
Soak a cotton wick in a strong solution of salt and water, dry it, place it in a spirit lamp, and when lit it will give a bright yellow light for a long time. If you look through a piece of blue glass at the flame, it willloseall its yellow light, and you will only perceive feeble violet rays. If, before the blue glass, you place a pale yellow glass, the lamp will be absolutely invisible, though a candle may be distinctly seen through the same glasses.
THE CHAMELEON FLOWERS.
Trim a spirit lamp, add a little salt to the wick, and light it. Set near it a scarlet geranium, and the flower will appear yellow. Purple colors, in the same light, appear blue.
TO CHANGE THE COLORS OF FLOWERS.
Hold over a lighted match a purple columbine, or a blue larkspur, and it will change first to pink, and then to black. The yellow of other flowers, held as above, will continue unchanged. Thus, the purple tint will instantly disappear from a heart's-ease, but the yellow will remain; and the yellow of a wall-flower will continue the same, though the brown streak will be discharged. If a scarlet, crimson, or maroon dahlia be tried, the color will change to yellow; a fact known to gardeners, who by this mode variegate their growing dahlias.
CHANGES OF THE POPPY.
Some flowers, which are red, become blue by merely bruising them. Thus, if the petals of the common corn-poppy be rubbed upon white paper, they will stain it purple, which may be made green by washing it over with a strong solution of potash in water. Put poppy petals into very dilute muriatic acid, and the infusion will be of a florid red color; by adding a little chalk, it will become of the color of port wine; and this tint, by the addition of potash, may be changed to green or yellow.
TO CHANGE THE COLOR OF A ROSE.
Hold a red rose over the blue flame of a common match, and the color will be discharged wherever the fume touches the leaves of the flower, so as to render it beautifully variegated, or entirely white. If it be then dipped into water, the redness, after a time, will be restored.
LIGHT CHANGING WHITE INTO BLACK.
Write upon linen with permanent ink (which is a strong solution of nitrate of silver), and the characters will be scarcely visible; remove the linen into a dark room, and they will not change; but expose them to a strong light, and they will be of an indelible black.
THE VISIBLY GROWING ACORN.
Cut a circular piece of card to fit the top of a hyacinth-glass, so as to rest upon the ledge, and exclude the air. Pierce a hole through the center of the card, and pass through it a strong thread, having a small piece of wood tied to one end, which, resting transversely on the card, prevents its being drawn through. To the other end of the thread attach an acorn; and having half filled the glass with water, suspend the acorn at a short distance from the surface.
The glass must be kept in a warm room; and, in a few days, the steam which has generated in the glass will hang from the acorn in a large drop. Shortly afterwards the acorn will burst,the root will protrude and thrust itself into the water; and in a few days more a stem will shoot out at the other end, and rising upwards, will press against the card, in which an orifice must be made to allow it to pass through. From this stem, small leaves will soon be observed to sprout; and in the course of a few weeks you will have a handsome oak plant, several inches in height.
COLORED FLAMES.
A variety of rays of light are exhibited by colored flames, which are not to be seen in white light. Thus, pure hydrogen gas will burn with a blue flame, in which many of the rays of light are wanting. The flame of an oil lamp contains most of the rays which are wanting in the sunlight. Alcohol, mixed with water, when heated or burned, affords a flame with no other rays but yellow. The following salts, if finely powdered, and introduced into the exterior flame of a candle, or into the wick of a spirit lamp, will communicate to the flame their peculiar colors:
Muriate of Soda (common salt)Yellow.Muriate of PotashPale violet.Muriate of LimeBrick red.Muriate of StrontiaBright crimson.Muriate of LithiaRed.Muriate of BarytaPale apple-green.Muriate of CopperBluish green.BoraxGreen.
Or, either of the above salts may be mixed with spirit of wine, as directed for Red Fire.
ORANGE COLORED FLAME.
Burn spirit of wine on chloride of calcium, a substance obtained by evaporating muriate of lime to dryness.
EMERALD GREEN FLAME.
Burn spirit of wine on a little powdered nitrate of copper.
INSTANTANEOUS FLAME.
Heat together potassium and sulphur, and they will instantly burn very vividly.
Heat a little niter on a fire-shovel, sprinkle on it flour of sulphur, and it will instantly burn. If iron filings be thrown upon red-hot niter, they will detonate and burn.
Pound, separately, equal parts of chlorate of potash and lump sugar; mix them, and put upon a plate a small quantity; dip a glass rod into sulphuric acid, touch the powder with it, and it will burst into a brilliant flame.
Or, put a few grains of chlorate of potash into a tablespoonful of spirit of wine; add one or two drops of sulphuric acid, and the whole will burst into a beautiful flame.
TO COOL FLAME BY METAL.
Encircle the very small flame of a floating night light, with a cold iron wire, which will instantly cause its extinction.
PROOF THAT FLAME IS HOLLOW.
Pour some spirit of wine into a watch-glass, and inflame it; place a straw across this flame, and it will only be ignited and charred at the outer edge; the middle of the straw will be uninjured, for there is no ignited matter in the center of the flame.
TO HOLD A HOT TEA KETTLE ON THE HAND.
Be sure that the bottom of the kettle is well covered with soot; when the water in it boils, remove it from the fire, and place it upon the palm of the hand; no inconvenience will be felt, as the soot will prevent the heat being transmitted from the water within and the heated metal, to the hand.
INCOMBUSTIBLE LINEN.
Make a strong solution of borax in water, and steep in it linen, muslin, or any article of clothing; when dry, they cannot easily be inflamed. A solution of phosphate of ammonia with sal ammoniac answers much better.
THE BURNING CIRCLE.
Light a stick, and whirl it round with a rapid motion, when its burning end will produce a complete circle of light, although that end can only be in one part of the circle at the same instant. This is caused by the duration of the impression of light upon the retina. Another example is, that during the winking of the eye we never lose sight of the object we are viewing.
WATER OF DIFFERENT TEMPERATURES IN THE SAME VESSEL.
Of heat and cold, as of wit and madness, it may be said that "thin partitions do their bounds divide." Thus, paint one half of the surface of a tin pot with a mixture of lamp-black and size, and leave the other half, or side, bright; fill the vessel with boiling water, and by dipping a thermometer, or even the finger, into it shortly after, it will be found to cool much more rapidly upon the blackened than upon the bright side of the pot.
WARMTH OF DIFFERENT COLORS.
Place upon the surface of snow, as upon the window sill, in bright daylight or sunshine, pieces of cloth of the same size and quality, but of different colors, black, blue, green, yellow, and white: the black cloth will soon melt the snow beneath it, and sink downwards; next the blue, and then the green; the yellow but slightly; but the snow beneath the white cloth will be as firm as at first.
SUBSTITUTE FOR FIRE.
Put into a cup a lump of quicklime, fresh from the kiln, pour water upon it, and the heat will be very great. A pailful of quicklime, if dipped in water, and shut closely into a box constructed for the purpose, will give out sufficient heat to warm a room, even in very cold weather. This is the source of steam vapor in theatrical representations.
LAUGHING GAS.
The above fanciful appellation has been given to nitrous oxide, from the very agreeable sensations excited by inhaling it. In its pure state it destroys animal life, but loses this noxious quality when inhaled, because it becomes blended with the atmospheric air which it meets in the lungs. This gas is made by putting three or four drams of nitrate of ammonia, in crystals, into a small glass retort, which being held over a spirit lamp, the crystals will melt, and the gas be evolved.
Having thus produced the gas, it is to be passed into a large bladder, having a stop-cock; and when you are desirous of exhibiting its effects, you cause the person who wishes to experience them, to first exhale the atmospheric air from the lungs, and then quickly placing the cock in his mouth, you turn it, and bid him inhale the gas. Immediately,a sense of extraordinary cheerfulness, fanciful flights of imagination, an uncontrollable propensity to laughter, and a consciousness of being capable of great muscular exertion, supervene. It does not operate in exactly the same manner on all persons; but in most cases the sensations are agreeable, and have this important difference from those produced by wine or spirituous liquors, that they are not succeeded by any depression of mind.
FLAME FROM COLD METALS.
Provide a bottle of the gas chlorine, which may be purchased of any operative chemist, and with it you may exhibit some brilliant experiments.
For example, reduce a small piece of the metal antimony to a very fine powder in a mortar; place some of this on a bent card, then loosen the stopper of the bottle of chlorine, and throw in the antimony; it will take fire spontaneously, and burn with much splendor, thus exhibiting a cold metal spontaneously bursting into flame.
If, however, a lump of antimony be dropped into the chlorine, there will be no spontaneous combustion, nor immediate change; but, in the course of time, the antimony will become incrusted with a white powder, and no chlorine will be found in the bottle.
Or, provide copper in fine leaves, known as "Dutch metal;" slightly breathe on one end of a glass rod, about ten inches long, and cause one or two leaves of the metal to adhere to the damp end; then open a bottle of chlorine, quickly plunge in the leaves, when they will instantly take fire, and burn with a fine red light, leaving in the bottle a greenish-yellow solid substance.
A smalllumpof copper, or "Dutch metal," will not burn as above, but will be slowly acted upon, like the antimony.
Immerse gold leaf in a jar of chlorine gas, and combustion with a beautiful green flame will take place.
PHOSPHORUS IN CHLORINE.
Put into a deflagrating spoon about four grains of phosphorus, and let it down into a bottle of chlorine, when the phosphorus will ignite instantaneously.
Or, fold a slip of blotting-paper into a match five inches long; dip it into oil of turpentine, drain it an instant, dropit into another bottle of chlorine, when it will burst into a flame, and deposit much carbon.
MAGIC VAPOR.
Provide a glass tube, about three feet long and half an inch in diameter; nearly fill it with water, upon the surface of which pour a little colored ether; then close the open end of the tube carefully with the palm of the hand, invert it in a basin of water, and rest the tube against the wall: the ether will rise through the water to the upper end of the tube; pour a little hot water over the tube, and it will soon cause the ether to boil within, and its vapor may thus be made to drive nearly all the water out of the tube into the basin; if, however, you then cool the tube by pouring cold water over it, the vaporized ether will again become a liquid, and float upon the water as before.
GAS FROM THE UNION OF METAL.
Nearly fill a wine-glass with diluted sulphuric acid, and place in it a wire of silver and another of zinc, taking care that they do not touch each other; when the zinc will be changed by the acid, but the silver will remain inert. But cause the upper ends of the wires to touch each other, and a stream of gas will issue from them.
CAMPHOR SUBLIMED BY FLAME.
Set a metallic plate over the flame of a spirit lamp; place upon it a small portion of camphor under a glass funnel; and the camphor will be beautifully sublimed by the heat of the lamp, in an efflorescent crust on the sides of the funnel.
GREEN FIRE.
A beautiful green fire may be thus made. Take of flour of sulphur thirteen parts, nitrate of baryta seventy-seven, oxymuriate of potassa five, metallic arsenic two, and charcoal three. Let the nitrate of baryta be well dried and powdered; then add to it the other ingredients, all finely pulverized, and exceedingly well mixed and rubbed together. Place a portion of the composition in a small tin pan, having a polished reflector fitted to one side, and set light to it; when a splendid green illumination will be the result. By adding a little calamine, it will burn more slowly.
BRILLIANT RED FIRE.
Weigh five ounces of dry nitrate of strontia, one ounce and a half of finely powdered sulphur, five drams of chlorate of potash, and four drams of sulphuret of antimony. Powder the chlorate of potash and the sulphuret of antimony separately in a mortar, and mix them on paper; after which add them to the other ingredients, previously powdered and mixed. No other kind of mixture than rubbing together on paper is required. For use, mix with a portion of the powder a small quantity of spirits of wine, in a tin pan resembling a cheese toaster, light the mixture, and it will shed a rich crimson hue. When the fire burns dim and badly, a very small quantity of finely powdered charcoal or lamp black will revive it.
PURPLE FIRE.
Dissolve chloride of lithium in spirit of wine, and when lighted, it will burn with a purplish flame.
SILVER FIRE.
Place upon a piece of burning charcoal a morsel of the dried crystals of nitrate of silver (not the lunar caustic), and it will immediately throw out the most beautiful sparks that can be imagined, whilst the surface of the charcoal will be coated with silver.
THE FIERY FOUNTAIN.
Put into a glass tumbler fifteen grains of finely granulated zinc, and six grains of phosphorus, cut into very small pieces beneath water. Mix in another glass, gradually, a dram of sulphuric acid, with two drams of water. Remove both glasses into a dark room, and there pour the diluted acid over the zinc and phosphorus in the glass; in a short time beautiful jets of bluish flame will dart from all parts of the surface of the mixture; it will become quite luminous, and beautiful luminous smoke will rise in a column from the glass, thus representing a fountain of fire.
COMBUSTION WITHOUT FLAME.
Light a smallgreenwax taper; in a minute or two, blow out the flame, and the wick will continue red hot for many hours; and if the taper were regularly and carefully uncoiled, and the room kept free from the current of air, the wick would burn on in this manner until the whole wasconsumed. The same effect is not produced when the color of the wax is red, on which account red wax tapers are safer than green, for the latter, if left imperfectly extinguished, may set fire to any object with which they are in contact.
COMBUSTION OF THREE METALS.
Mix a grain or two of potassium with an equal quantity of sodium; add a globule of quicksilver, and the three metals, when shaken, will take fire, and burn vividly.
TO MAKE PAPER APPARENTLY INCOMBUSTIBLE.
Take a smooth cylindrical piece of metal, about one inch and a half in diameter, and eight inches long; wrap very closely round it a piece of clean writing paper, then hold the paper in the flame of a spirit lamp, and it will not take fire; but it may be held there for a considerable time, without being in the least affected by the flame. If the paper be strained over a cylinder of wood, it is quickly scorched.
HEAT NOT TO BE ESTIMATED BY TOUCH.
Hold both hands in water which causes the thermometer to rise to ninety degrees, and when the liquid has become still, you will be insensible to the heat, and that the hand is touching anything. Then remove one hand to water that causes the thermometer to rise to two hundred degrees, and the other in water at thirty-two degrees. After holding the hands thus for some time, remove them, and again immerse them in the water at ninety degrees; when you will findwarmthin one hand andcoldin the other. To the hand which had been immersed in the water at thirty-two degrees, the water at ninety degrees will feel hot; and to the hand which had been immersed in the water at two hundred degrees, the water at ninety degrees will feel cool. If, therefore, the touch in this case be trusted, the same water will be judged to be hot and cold at thesametime.
FLAME UPON WATER.
Fill a wine glass with cold water, pour lightly upon its surface a little ether; light it by a slip of paper, and it will burn for some time.
ROSE-COLORED FLAME UPON WATER.
Drop a globule of potassium, about the size of a large pea, into as small cup, nearly full of water, containing a drop ortwo of strong nitric acid; the moment that the metal touches the liquid, it will float upon its surface, enveloped with a beautiful rose-colored flame, and entirely dissolve.
TO SET A MIXTURE ON FIRE WITH WATER.
Pour into a saucer a little sulphuric acid, and place upon it a chip of sodium, which will float and remain uninflamed; but the addition of a drop of water will set it on fire.
WAVES OF FIRE ON WATER.
On a lump of refined sugar let fall a few drops of phosphuretted ether, and put the sugar into a glass of warm water, which will instantly appear on fire at the surface, and in waves, if gently blown with the breath. This experiment should be exhibited in the dark.
WATER FROM THE FLAME OF A CANDLE.
Hold a cold and dry bell glass over a lighted candle, and watery vapor will be directly condensed on the cold surface; then close the mouth of the glass with a card or plate, and turn the mouth uppermost; remove the card, quickly pour in a little lime-water, a perfectly clear liquid, and it will instantly become turbid and milky, upon meeting with the contents of the glass, just as lime-water changes when dropped into a glass full of water.
FORMATION OF WATER BY FIRE.
Put into a tea cup a little spirit of wine, set it on fire, and invert a large bell-glass over it. In a short time, a thick watery vapor will be seen upon the inside of the bell, which may be collected by a dry sponge.
BOILING UPON COLD WATER.
Provide a tall glass jar, filled with cold water, and place in it an air thermometer, which will nearly reach the surface; upon the surface place a small copper basin, into which put a little live charcoal: the surface of the water will soon be made to boil, while the thermometer will show that the water beneath is scarcely warmer than it was at first.
CURRENTS IN BOILING WATER.
Fill a large glass tube with water, and throw into it a few particles of bruised amber, then hold the tube by ahandle for the purpose, upright in the flame of a lamp, and as the water becomes warm, it will be seen that currents, carrying with them the pieces of amber, will begin to ascend in the center, and to descend towards the circumference of the tube. These currents will soon become rapid in their motions, and continue till the water boils.
HOT WATER LIGHTER THAN COLD.
Pour into a glass tube, about ten inches long, and one inch in diameter, a little water colored with pink or other dye; then fill it up gradually and carefully with colorless water, so as not to mix them; apply heat at the bottom of the tube, and the colored water will ascend and be diffused throughout the whole.
The circulation of warm water may be very pleasingly shown, by heating water in a tube similar to the foregoing; the water having diffused in it some particles of any light substance not soluble in water.
EXPANSION OF WATER BY COLD.
All fluids, except water, diminish in bulk till they freeze. Thus, fill a large thermometer tube with water, say of the temperature of eighty degrees, and then plunge the bulb into pounded ice and salt, or any other freezing mixture: the water will go on shrinking in the tube till it has attained the temperature of about forty degrees; and then, instead of continuing to contract till it freezes, (as in the case with all other liquids), it will be seen slowly to expand, and consequently to rise in the tube, until it congeals. In this case, the expansion below forty degrees, and above forty degrees, seem to be equal; so that the water will be of the same bulk at thirty-two degrees as at forty-eight degrees, that is, at eight degrees above or below forty degrees.
THE CUP OF TANTALUS.
This pretty toy may be purchased at any optician's for two or three shillings. It consists of a cup, in which is placed a standing human figure, concealing a syphon, or bent tube with one end longer than the other. This rises in one leg of the figure to reach the chin, and descends through the other leg, through the bottom of the cup to a reservoir beneath. If you pour water in the cup, it will risein the shorter leg by its upward pressure, driving out the air before it through the longer leg; and when the cup is filled above the bend of the syphon, (that is, level with the chin of the figure,) the pressure of the water will force it over into the longer leg of the syphon, and the cup will be emptied: the toy thus imitating Tantalus of mythology, who is represented by the poets as punished in Erebus with an insatiable thirst, and placed up to the chin in a pool of water, which, however, flowed away as soon as he attempted to taste it.
THE MAGIC WHIRLPOOL.
Fill a glass tumbler with water, throw upon its surface a few fragments or thin shavings of camphor, and they will instantly begin to move, and acquire a motion both progressive and rotary, which will continue for a considerable time. During these rotations, if the water be touched by any substance which is at all greasy, the floating particles will quickly dart back, and as if by a stroke of magic, be instantly deprived of their motion and vivacity.
In like manner, if thin slices of cork be steeped in sulphuric ether in a closed bottle for two or three days, and then placed upon the water, they will rotate for several minutes, like the camphor; until the slices of cork having discharged all their ether, and become soaked with water, they will keep at rest.
If the water be made hot, the motion of the camphor will be more rapid than in cold water, but it will cease in proportionately less time. Thus, provide two glasses, one containing water at fifty-eight degrees, and the other at two hundred and ten degrees; place raspings of camphor upon each at the same time; the camphor in the first glass will rotate for about five hours, until all but a very minute portion has evaporated, while the rotation of the camphor in the hot water will last only nineteen minutes: about half the camphor will pass off, and the remaining pieces, instead of being dull, white, and opaque, will be vitreous and transparent, and evidently soaked with water. The gyrations, too, which at first will be very rapid, will gradually decline in velocity, until they become quite sluggish.
The stilling influence of oil upon waves has become proverbial: the extraordinary manner in which a small quantity of oil instantly spreads over a very large surface oftroubled water, and the stealthy manner in which even a rough wind glides over it, must have excited the admiration of all who have witnessed it.
By the same principle a drop of oil may be made to stop the motion of the camphor, as follows: Throw some camphor, both in slices and in small particles, upon the surface of water, and while they are rotating, dip a glass rod into oil of turpentine, and allow a single drop thereof to trickle down the inner side of the glass to the surface of the water; the camphor will instantly dart to the opposite point of the liquid surface, and cease to rotate. If a piece of hard tallow or lard be employed, the motion of the camphor will be more slowly stopped than by oil or fluid grease, as the latter spreads over the surface of the water with greater rapidity.
If a few drops of sulphuric or muriatic acid be let fall into the water, they will gradually stop the motion of the camphor; but if camphor be dropped into nitric acid diluted with its own bulk of water, it will rotate rapidly for a few seconds, and then stop.
If a piece of the rotating camphor be attentively examined with a lens, the currents of the water can be well distinguished, jetting out, chiefly from the corners of the camphor, and bearing it round with irregular force.
The currents, as given out by the camphor, may also be seen by means of the microscope; a drop or two of pure water being placed upon a slip of glass, with a particle of camphor floating upon it. By this means the current may be detected, and it will be seen that they cause the rotations.
Or a flat watch-glass, called alunar, may be employed, raised a few inches, and supported on a wire ring, kept steady by thrusting one end into an upright piece of wood, like a retort stand. Then put the camphor and water in the watch-glass, and place under the frame a sheet of white paper, so that it may receive the shadow of the glass, camphor, &c., to be cast by a steady light, placed above, and somewhat on one side of the watch glass. On observing the shadow, which may be considered a magnified representation of the object itself, the rotations and currents can be distinguished.
ARTIFICIAL FIRE BALLS.
Put thirty grains of phosphorus into a bottle, which contains three or four ounces of water. Place the vessel overa lamp, and give it a boiling heat. Balls of fire will soon be seen to issue from the water, after the manner of an artificial fire-work, attended with the most beautiful coruscations.
TO MELT STEEL AS EASILY AS LEAD.
Make a piece of steel red in the fire, then hold it with a pair of pincers or tongs; take in the other hand a stick of brimstone, and touch the piece of steel with it. Immediately after their contact, you will see the steel melt and drop like a liquid.
TO TELL A LADY IF SHE IS IN LOVE.
Put into a phial some sulphuric ether, color it red with orchanet, then saturate the tincture with spermaceti. This preparation is solid ten degrees above freezing point, and melts and boils at twenty degrees. Place the phial which contains it in a lady's hand, and tell her that if in love, the solid mass will dissolve. In a few minutes the substance will become fluid.
AN EGG PUT INTO A PHIAL.
To accomplish this seemingly incredible act, requires the following preparation: You must take an egg and soak it in strong vinegar; and in process of time its shell will become quite soft, so that it may be extended lengthways without breaking; then insert it into the neck of a small bottle, and by pouring cold water upon it, it will reassume its former figure and hardness. This is really a complete curiosity, and baffles those who are not in the secret to find out how it is accomplished. If the vinegar used to saturate the egg is not sufficiently strong to produce the required softness of shell, add one teaspoonful of strong acetic acid to every two tablespoonfuls of vinegar. This will render the egg perfectly flexible, and of easy insertion into the bottle, which must then be filled with cold water.
TO ASTONISH A LARGE PARTY.
With some lycopodium, powder the surface of a large or small vessel of water; you may then challenge any one to drop a piece of money into the water, and that you will get it with the hand without wetting your skin. The lycopodium adheres to the hand, and prevents its contact with the water. A little shake of the hand, after the feat is over, will dislodge the powder.
TEST PAPERS.
On the otherwise barren rocks which fringe the shore of the Cape de Verd Islands, grows the archil—a famous seaweed or lichen, renowned among dyers. By a particular process of manufacture, this archil yields a beautiful blue pigment, known in the chemical laboratory by the name oflitmus. Few colors are more fugitive than litmus. Being a fine violet-blue, it is changed to red by so minute a portion of any acid, that it becomes, when properly applied,a testof the presence of the latter substance. As it is so frequently desirable to know whether a fluid be acid or alkaline, one of the first practical lessons to a student in chemistry, is to prepare litmus test paper, thus: Put into a flask half an ounce of litmus, and three ounces of water; let them remain together in a warm place for a few hours, then filter the dark blue liquid from its impurities, divide the solution obtained into two parts, pour one portion into a saucer, and soak strips of white writing paper in it until it has acquired a distinct blue color. If not colored enough by once dipping and drying, repeat the operation. When dry, preserve these strips in a box, labeled "Blue litmus test papers." These serve totestany fluid, to ascertain if it has anacidreaction. It is instructive to learn how very small a portion of any acid in water will be indicated by the reddening of the litmus. With the second portion of the fluid, mix, cautiously, a few drops of lemon juice, until it is red; then color paper as before. When dry, this "red litmus test paper" serves to indicate the presence of alkalies, a class of bodies opposed to acids. Red litmus test paper, on being put into any fluid that isalkaline, such as lime-water, is immediately restored to its original blue color. Put the ashes of a cigar into water, the liquid, when "tested," will indicate the presence of an alkali. Test some stale milk. If your blue paper becomes red, the milk is sour; it is acid.