Part 6

Put oyster-shells into a common fire; burn them for about half an hour; then remove them into a dark room, when many of the shells will exhibit beautiful specimens of prismatic colours.

RINGS OF LIGHT IN CRYSTAL.

This is one of the most striking of optical exhibitions, and may be thus simply produced. Provide a sheet of clear ice, about an inch thick, frozen in still weather; let the light fall through the ice upon a pane of window-glass, or a polished table, and by placing a fragment of plate-glass near the eye as a reflector, the most beautiful rings of light may be observed.

TO STRIKE LIGHT WITH CANE.

Strike a piece of rattan cane with a steel, and it contains so much silex, or flint, that it will exhibit sparks of light in the dark.

CAUSE OF TRANSPARENCY.

Moisten a piece of paper, and it will appear more transparent than when in its natural state; the cause of which is as follows: a piece of dry paper has its pores obstructed with finely interwoven threads; these are broken by the liquor, which also fills the pores as so many small tubes, and permits the light to pass through it, whereas the dry threads had hitherto prevented its passage.

TRANSPARENCY OF GOLD.

All bodies are more or less transparent. Thus, though gold is one of the densest metals, yet, if a piece of the thinnest gold-leaf be held up to a candle, the light will pass through it; and, that it passes through the substance of the metal, and not through cracks or holes too small to be detected by the eye, is evident from the colour of the transmitted light, which is green.

TINT CHANGED BY THICKNESS.

Provide a piece of plain and polished smalt-blue glass, such as sugar-basins and finger glasses are made of. It should be of unequal thickness. Look through this glass at a strong light, as that from the crack of a window-shutter, in a darkened room, and, at the thinnest part, the colour will be purely blue. As the thickness increases, a purple tinge will come on, which will become more and more ruddy; and, if the glass be very thick, the colour will pass to a deep red.

SHADOWS MADE DARKER BY INCREASED LIGHT.

Hold a finger between a candle and the wall, and it will cast a shadow of a certain darkness; then place another candle in the same line with the other from the wall, and the shadow will appear doubly dark, although there will be more light in the room than before. Then separate the candles, and place them so as to produce two shadows of the finger, one partly overlapping the other, and that part will be of double darkness, as compared with the remainders.

MINIATURE THUNDER AND LIGHTNING.

To imitate thunder, provide a thin sheet of iron; hold it by one corner between the finger and thumb, and allow it to hang freely by its own weight. Then shake the hand horizontally, so as to agitate the corner in a direction at right angles to the surface of the sheet. Thus you may produce a great variety of sounds, from the deep growl of distant thunder to those loud claps which rattle in rapid succession immediately over our heads. The same effect may be produced by sheets of tinned iron, or tin-plate, and by thin plates of mica; but the sound is shorter and more acute.

Partial flashes of lightning, aurora borealis, &c., may be beautifully imitated by taking in a spoon about a dram of the seeds of lycopodium, and throwing them against a lighted candle, all other light being excluded from the room.

A similar effect may be produced, by laying some powdered resin on a piece of paper, and fillipping it with the finger against the flame of a candle.

THE BURNING GLASS.

If, when the sun shines brightly, a piece of paper be held in the focus of the rays drawn by the burning-glass, it will take fire. This experiment succeeds best with brown or any dark-coloured paper: for, though the glass will collect an equal number of rays upon white as upon coloured paper, the white paper reflects the rays instead of allowing them to enter it; hence, the white is not so soon burnt as the coloured paper, which absorbing more light than it reflects, soon becomes heated and takes fire.

MAGIC OF HEAT.

Melt a small quantity of the sulphate of potass 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 colour. Remove the spoon from the flame, when the liquid will become a solid of a brilliant emerald-green colour, 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.

REPULSION 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 grey 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 vapour of sulphur is very powerfully repelled by heated glass. The flattened form of the particles is owing to the force with which they endeavour 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., to be a satisfactory argument in favour 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, and the 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 is 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 little chlorate of potass with spirit of wine in a strong saucer; add a little sulphuric acid, and an orange vapour will arise and burst into flame.

INEQUALITY OF HEAT IN FIRE-IRONS.

Place before a brisk fire a set of polished fire-irons, and besides them a rough unpolished poker, such as is used in a kitchen, or 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 lustre: 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.

A FLOATING METTLE ON FIRE.

Throw a small piece of that marvellous substance, potassium, into a basin of water, and it will swim upon the surface, and burn with a beautiful light, of a red colour mixed with violet. When moderately heated in the air, potassium takes fire, and burns with a red light.

HEAT AND COLD FROM FLANNEL.

Put a piece of ice into a basin, which wrap up in many folds of flannel, and the ice may be preserved for some time by the fireside.

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.

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.

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 twinkling 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 COLOURS.

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 colours, 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 quick-lime, fresh from the kiln, pour water upon it, and the heat will be very great. A pailful of quick-lime, 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.

GAS AND STEAM.

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.

THE LUMINOUS WAND.

Cover a long slip of wood, half-way, with sulphur, by immersion while in a melted state. Having prepared a jar of nitrous oxide gas, as in preceding experiments, light the sulphur, and plunge the wand into the jar. The gas will extinguish the flame. Withdraw the wand, light it again, and when the flame is very brilliant, immerse it again in the jar. It will this time burn with great splendour, and of a beautiful red colour.

TO MAKE CARBONIC ACID GAS.

Put about an ounce of marble in small lumps, into an eight ounce phial, with about an equal quantity of water; pour in a little muriatic acid, and carbonic acid gas will be evolved.

CARBONIC ACID GAS IN WINE OR BEER VESSELS.

The apparently empty or upper part of vessels in which wine or beer is working, is filled with this deleterious gas; for its great weight prevents its ascent from the fermenting liquid. A variety of striking but simple experiments may be made with the gas in this condition. Lighted paper, or a candle dipped into it, will be immediately extinguished; and the smoke remaining in the carbonic acid gas will render its surface visible, which may be thrown into waves by agitation, like water. In consequence of the great weight of the carbonic acid gas, it may be taken from a vat of fermenting liquor, in a jug or bottle, and in the latter, if well corked, it may be conveyed to great distances; or the gas may be drawn out of a vessel by a cock, like a liquid.

TO EXTINGUISH FLAME WITH GAS.

The effects produced by pouring carbonic acid gas from one vessel to another, have a very singular appearance: if a lighted candle be placed in a jar, and the gas be poured upon it, the flame will be extinguished in a few seconds, though the eye is incapable of distinguishing that anything is poured out.

EFFECT OF HYDROGEN ON THE VOICE.

Make a hole through a wine cork of sufficient size to admit a smaller cork; through which make another hole, and fix it into the larger one. Tie the corks thus fixed into the neck of a bullock’s bladder, previously exhausted of air; let a tube from a bottle generating hydrogen pass very tightly through the aperture in the small cork, and the gas will distend and fill the bladder. The instant it is full, withdraw the inner cork, and either prevent the escape of the gas by means of the thumb, or cork it closely, till the operator is ready to _breathe the gas_; to do which, he should put the open cork into his mouth, and take _one_ inspiration, when, on immediately speaking, his voice will be remarkably shrill. The effect will pass off in a few seconds.

MAGIC TAPER.

Provide a piece of copper wire, about ten inches long, and fix at one end of it a piece of wax taper: take a pint bottle of hydrogen, and place the mouth downwards; light the taper, introduce it into the bottle, and the gas will take fire, and burn slowly towards the mouth, where it is in contact with the air. If, however, the taper be passed up into the bottle, it will be extinguished; but, on gently withdrawing it through the burning hydrogen, the wick will be rekindled. This may be done several times in succession with the same portion of gas.

THE GAS CANDLE.

Provide a strong glass bottle which will contain about eight ounces, or half a pint, into which put a few pieces of zinc; then mix half an ounce of sulphuric acid with four ounces of water, and pour it into the bottle upon the zinc; fit the mouth closely with a cork, through which put a metal tube which ends upward in a fine opening: the mixture in the bottle will soon effervesce, and hydrogen gas will rise through the tube. When it has escaped for about a minute, apply a lighted paper to the tube, and the gas will burn like a candle, but with a pale flame. Its brightness may be increased to brilliance, by sifting over it a small quantity of magnesia.

GAS BUBBLES.

Provide a bladder, fill it with hydrogen gas, to be made as for the last experiment, and fit the end of a tobacco-pipe closely into the bladder; dip the bowl of the pipe into soap and water, and, by pressing the bladder, soap-bubbles will be formed, filled with hydrogen gas; which bubbles, or balloons, will rise in the air, and keep there for some time.

GAS-LIGHT IN THE DAY-TIME.

Light a stream of hydrogen gas, and it will be scarcely visible in the day-light; but place in it a small coil of platinum wire, or project a little oxide of zinc through the flame, and it will become very luminous.

MINIATURE BALLOONS.

One of the simplest and most beautiful experiments in aërostation, is to take a turkey’s maw, or stomach, properly prepared, and to fill it either with pure hydrogen gas, or the carburetted hydrogen produced from coal. If the balloon be then allowed to escape in the open air, it will ascend rapidly in the atmosphere: but the best method of showing the experiment, is to let the balloon off a high staircase, and observe it ascend to the cupola or light, where it will remain near the highest point till the escape of the gas allow it to descend. The prepared maw for this balloon may be purchased of any optician.

MINIATURE GAS-LIGHTING.

Bicarburetted hydrogen is the principal constituent of the gas burned in the streets: it is procured from coal, and the process may readily be performed on a small scale. Put about two ounces of pounded coal into an earthen retort, and fix a glass tube into the neck, terminating in an aperture of one-fifth of an inch in diameter; heat the retort red-hot, and apply the flame of a taper to the orifice of the tube, when the gas will burn with a bright white light, very different from that afforded by the combustion of hydrogen; a circumstance owing to the presence of particles of carbon in the carburet, which being intensely ignited, are highly luminous.

It is no less strange than true, that bicarburetted hydrogen, the substance which we so largely consume to illuminate our towns, is ether when united to water in one proportion, and spirit when combined with it in another; a fluid which constitutes the strength of all wines, beer, and fermented liquors.

MUSICAL GAS.

Into a half-pint glass bottle, put some zinc, granulated by being melted in a ladle, and then poured gradually into water. Add some sulphuric acid, diluted with eight parts by weight of water. Then pass a glass tube with a capillary bore, through a cork, which you have previously made to closely fit the bottle, and cork the bottle well. In a short time, the atmospheric air will be expelled, and hydrogen gas will rise through the tube; you then apply a light, and the gas will become ignited. If you now hold another glass tube, about eighteen or twenty inches long over the flame sufficiently wide to enclose the other tube very loosely (_see engraving_), the little speck of flame will sport along the larger tube, and musical sounds will be produced, which may be varied by using other tubes of different dimensions, and made of different materials; the wide tubes forming the lower, and the narrow tubes the upper notes.

MINIATURE WILL O’-THE-WISP.

Put a small piece or two of the phosphuret of lime into a saucer of water, when bubbles of phosphuretted hydrogen gas will rise to the surface, explode into flame, and cause a white smoke; representing, on a small scale, the _ignis fatuus_, or will o’-the-wisp, as seen over marshy ground, or stagnant pools of water.

PHOSPHORIC ILLUMINATION.

A light so brilliant that the eye can scarcely bear to contemplate it, is produced by the immersion of phosphorus in oxygen gas. To perform this experiment, you place a piece of phosphorus in a copper cup, of the circumference of a sixpence, which is fastened to a thick piece of iron wire, attached to a cork which fits a bottle (as in the foregoing experiment) filled with oxygen gas. Set fire to the phosphorous, and quickly plunge it into the bottle; when the splendour of the combustion will be surpassingly beautiful.

It is necessary to observe, that the heat is so excessive, that if the piece of phosphorous in this experiment be larger than a small pea, there will be great danger of breaking the bottle.

COMBUSTION OF IRON IN OXYGEN GAS.

Twist a piece of fine iron wire, such as is used by piano-forte makers, round a cylindrically-shaped piece of wood or metal, which will give it a spiral form; or a broken watch-spring, which may be bought for a trifle of the watch-makers, will answer the same purpose. Fasten round one end of it some waxed cotton thread or twine, and attach the other end to a cork, which fits a glass jar or bottle, that will hold a quart, filled with oxygen gas. Having made the wire red-hot by setting light to the thread, plunge it into the bottle. Do not cork the bottle, but let the cork merely lay on the mouth, and to prevent its being burned, a small a piece of lead should be fastened to the bottom of it. The iron will instantly begin to burn with great brilliancy, throwing out luminous scintillations.

To prevent the bottle from being broken by the sparks, a small quantity of sand should be previously poured into it.

GLOW-WORM IN OXYGEN GAS.

If a glow-worm be placed in a jar of oxygen gas, in a dark room, it will shine with a far surpassing brilliancy to that which it exhibits in atmospheric air.

LUMINOUS CHARCOAL.

Attach a small piece of charcoal to the end of a copper-wire; make it red-hot, and immerse it in a jar of oxygen gas. The charcoal will burn with great brilliance, throwing out splendid scintillations. The bark of the wood converted into charcoal must be selected, otherwise there will be no scintillations.

BRILLIANT COMBUSTION IN OXYGEN.

Place in a bottle of oxygen gas a lighted taper, and it will burn with a flame of increased brilliancy.

Extinguish the taper immediately; put it into the same or another bottle of oxygen, and it will be again lighted provided a spark remain on the wick.

Bend a piece of iron wire in a spiral form, and tie on to one end some cotton or flax; sprinkle some flour of sulphur on it, set it on fire, dip it into a bottle of oxygen gas, and beautiful corruscations will be thrown off the wire.

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 power 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 splendour; thus exhibiting a cold metal spontaneously bursting into flame.