Part 12
Dissolve copper filings in aqua fortis. When the copper has impregnated the acid, pour off the solution, and put into it some pieces of iron, or iron filings. The effect of this will be to sink the powder to the bottom of the acid. Pour off the liquor, and wash the powder in successive quantities of fresh water. When the powder is dry, it is to be rubbed on the figure with a soft cloth, or piece of leather; but observe, that previously to the application of the bronze powder, a dark blackish sort of green is first to be laid on the figure: and if you wish the powder to adhere stronger, mix it with gum-water, lay it on like paint, with a camels'-hair brush, or previously trace the parts to be bronzed with gold size, and when nearly dry, rub the powder over it.
_Method of taking the Impression of Butterflies on Paper._
Clip the wings off the butterfly, lay them on clean, in the form of a butterfly when flying. Spread some thick clean gum-water on another piece of paper, press it on the wings, and it will take them up; lay a piece of white paper over it, and rub it gently with your finger, or the smooth handle of a knife. The bodies are to be drawn in the space which you leave between the wings.
_To soften Horn._
To one pound of wood-ashes, add two pounds of quick lime; put them into a quart of water. Let the whole boil till reduced to one-third. Then dip a feather in, and if, on drawing it out, the plume should come off, it is a proof that it is boiled enough; if not, let it boil a little longer. When it is settled, filter it off, and in the liquor thus strained put in shavings of horn. Let them soak for three days; and, first anointing your hands with oil, work the horn into a mass, and print or mould it into any shape you please.
_To make Moulds of Horn._
If you wish to take the impression of any coin, medal, &c., previously anoint it with oil; then lay the horn shavings over it in its softened state. When dry, the impression will be sunk into the horn; and this will serve as a mould to re-produce, either by plaster-of-paris, putty and glue, or isinglass and ground egg-shells, the exact resemblance of the coin or medal.
_To cast Figures in Imitation of Ivory._
Make isinglass and strong brandy into a paste, with powder of egg-shells, very finely ground. You may give it what colour you please; but cast it warm into your mould, which you previously oil over. Leave the figure in the mould till dry, and you will find, on taking it out, that it bears a very strong resemblance to ivory.
_To extract the Silver out of a Ring that is thick gilded, so that the Gold may remain entire._
Take a silver ring that is thick gilded. Make a little hole through the gold into the silver; then put the ring into aqua fortis, in a warm place: it will dissolve the silver, and the gold will remain whole.
_To soften Iron or Steel._
Either of the following simple methods will make iron or steel as soft as lead:
1. Anoint it all over with tallow; temper it in a gentle charcoal fire, and let it cool of itself.
2. Take a little clay, cover your iron with it, temper it in a charcoal fire.
3. When the iron or steel is red-hot, strew hellebore on it.
4. Quench the iron or steel in the juice or water of common beans.
_To take a Plaster-of-Paris Cast from a Person's Face._
The person must lie on his back, and his hair be tied behind. Into each nostril put a conical piece of paper, open at each end to allow of breathing. The face is to be lightly oiled over, and the plaster being properly prepared is to be poured over the face, (taking care that the eyes are shut,) till it is a quarter of an inch thick. In a few minutes the plaster may be removed. In this a mould is to be formed, from which a second cast is to be taken, that will furnish casts exactly like the original.
_Curious Experiment with a Glass of Water._
Saturate a certain quantity of water in a moderate heat, with three ounces of sugar; and when it will no longer receive that, there is still room in it for two ounces of salt of tartar, and after that for an ounce and a drachm of green vitriol, nearly six drachms of nitre, the same of sal-ammoniac, two drachms and a scruple of alum, and a drachm and half of borax.
_To make Artificial Coruscations._
There is a method of producing artificial coruscations, or sparkling fiery meteors, which will be visible, not only in the dark but at noon-day, and that from two liquors actually cold. The method is this:--Fifteen grains of solid phosphorus are to be melted in about a drachm of water: when this is cold, pour upon it two ounces of oil of vitriol; let these be shaken together in a large phial, and they will at first heat, and afterwards will throw up fiery balls in great number, which will adhere like so many stars to the sides of the glass, and continue burning a considerable time; after this, if a small quantity of oil of turpentine be poured in without shaking the phial, the mixture will of itself take fire, and burn very furiously. The vessels should be large and open at the top.
_Another Method._
Artificial coruscations may also be produced by means of oil of vitriol and iron, in the following manner:--Take a glass vessel capable of holding three quarts: put into this three ounces of oil of vitriol, and twelve ounces of water, then warming the mixture a little, throw in at several times two ounces, or more, of clear iron filings: upon this, an ebullition and white vapours will arise; then present a lighted candle to the mouth of the vessel, and the vapour will take fire, and afford a bright fulmination or flash; like lightning. Applying the candle in this manner several times, the effect will always be the same; and sometimes the fire will fill the whole body of the glass, and even circulate to the bottom of the liquor; at others, it will only reach a little down its neck. The great caution to be used in making this experiment, is the making the vapour of a proper heat; for if made too cold few vapours will arise; and, if made too hot, they will arise too fast, and will only take fire in the neck of the glass, without any remarkable coruscation.
_To produce Fire from Cane._
The Chinese rattans, which are used, when split, for making cane chairs, will, when dry, if struck against each other, give fire; and are used accordingly in some places, in lieu of flint and steel.
_To make an Eolian Harp._
This instrument may be made by almost any carpenter: it consists of a long narrow box of very thin deal, about five or six inches deep, with a circle in the middle of the upper side, of an inch and a half in diameter, in which are to be drilled small holes. On this side, seven, ten, or more strings, of very fine gut, are stretched over bridges at each end, like the bridges of a fiddle, and screwed up or relaxed with screw pins. The strings must be all tuned to one and the same note, and the instrument be placed in some current of air, where the wind can pass over its strings with freedom. A window, of which the width is exactly equal to the length of the harp, with the sash just raised to give the air admission, is a proper situation. When the air blows upon these strings, with different degrees of force, it will excite different tones of sounds; sometimes the blast brings out all the tones in full concert, and sometimes it sinks them to the softest murmurs.
_To show the Pressure of the Atmosphere._
Invert a tall glass or jar in a dish of water, and place a lighted taper under it: as the taper consumes the air in the jar its pressure becomes less on the water immediately under the jar; while the pressure of the atmosphere on the water _without_ the circle of the jar remaining the same, part of the water in the dish will be forced up into the jar, to supply the place of the air which the taper has consumed. Nothing but the pressure of the atmosphere could thus cause part of the water to rise within the jar, above its own level.
_Subaqueous Exhalation._
Pour a little clear water into a small glass tumbler, and put one or two small pieces of phosphoret of lime into it. In a short time, flashes of fire will dart from the surface of the water, and terminate in ringlets of smoke, which will ascend in regular succession.
_Remarkable Properties in certain Plants._
Plants, when forced from their natural position, are endowed with a power to restore themselves. A hop-plant, twisting round a stick, directs its course from south to west, as the sun does. Untwist it, and tie it in the opposite direction, it dies. Leave it loose in the wrong direction, it recovers its natural direction in a single night. Twist a branch of a tree so as to invert its leaves, and fix it in that position; if left in any degree loose, it untwists itself gradually, till the leaves be restored to their natural position. What better can an animal do for its welfare? A root of a tree meeting with a ditch in its progress, is laid open to the air; what follows? It alters its course like a rational being, dips into the ground, surrounds the ditch, rises on the opposite side of its wonted distance from the surface, and then proceeds in its original direction. Lay a wet sponge near a root exposed to the air; the root will direct its course to the sponge; change the place of the sponge, the root varies its direction. Thrust a pole into the ground at a moderate distance from a climbing plant; the plant directs its course to the pole, lays hold of it, and rises on its natural height. A honeysuckle proceeds in its course, till it be too long for supporting its weight, and then strengthens itself by shooting into a spiral. If it meet with another plant of the same kind, they coalesce for mutual support; the one screwing to the right, the other to the left. If a honeysuckle twig meet with a dead branch, it screws from the right to the left. The claspers of briony shoot into the spiral, and lay hold of whatever comes in their way, for support. If, after completing a spiral of three rounds, they meet with nothing, they try again, by altering their course.
_Flowers curiously affected by the Sun and the Weather._
The petals of many flowers expand in the sun, but contract all night, or on the approach of rain; after the seeds are fecundated the petals no longer contract. All the trefoil may serve as a barometer to the husbandman; they always contract their leaves on an impending storm.
_Easy Method of obtaining Flowers of different Colours from the same Stem._
Scoop out the pith from a small twig of elder, and having split it lengthwise, fill each of the parts with small seeds that produce flowers of different colours, but that blossom nearly at the same time. Surround them with earth; and then tying together the two bits of wood, plant the whole in a pot filled with earth, properly prepared.
_A Luminous Bottle, which will show the Hour on a Watch in the Dark._
Throw a bit of phosphorus, of the size of a pea, into a long glass phial, and pour boiling oil carefully over it, till the phial is one-third filled. The phial must be carefully corked, and when used should be unstopped, to admit the external air, and closed again. The empty space of the phial will then appear luminous, and give as much light as an ordinary lamp. Each time that the light disappears, on removing the stopper it will instantly re-appear. In cold weather the bottle should be warmed in the hands before the stopper is removed. A phial thus prepared may be used every night for six months.
_To make Luminous Writing in the Dark._
Fix a small piece of solid phosphorus in a quill, and write with it upon paper; if the paper be carried into a dark room, the writing will appear beautifully luminous.
_The Sublimated Tree._
Into a large glass jar inverted upon a flat brick tile, and containing near its top a branch of fresh rosemary, or any other such shrub, moistened with water, introduce a flat thick piece of heated iron, on which place some gum benzoin, in gross powder. The benzoin, in consequence of the heat, will be separated, and ascend in white fumes, which will at length condense, and form a most beautiful appearance upon the leaves of the vegetable.
_Easy and curious Methods of foretelling Rainy or Fine Weather._
If a line be made of good whipcord, that is well dried, and a plummet affixed to the end of it, and then hung against a wainscot, and a line drawn under it, exactly where the plummet reaches, in very moderate weather it will be found to rise above it before rain, and to sink below when the weather is likely to become fair. But the best instrument of all, is a good pair of scales, in one of which let there be a brass weight of a pound, and in the other a pound of salt, or of saltpetre, well dried; a stand being placed under the scale, so as to hinder it falling too low. When it is inclined to rain, the salt will swell, and sink the scale: when the weather is growing fair, the brass weight will regain its ascendancy.
_Contrivance for a Watch Lamp, perfectly safe, which will show the Hour of the Night, without any trouble, to a person lying in Bed._
It consists of a stand, with three claws, the pillar of which is made hollow, for the purpose of receiving a water candlestick of an inch diameter. On the top of the pillar, by means of two hinges and a bolt, is fixed on a small proportionate table, a box of six sides, lined with brass, tin, or any shining metal, nine inches deep, and six inches in diameter. In the centre of one of these sides is fixed a lens, double convex, of at least three inches and a half diameter. The centre of the side directly opposite to the lens is perforated so as to receive the dial-plate of the watch, the body of which is confined on the outside, by means of a hollow slide. When the box is lighted by a common watch-light, the figures are magnified nearly to the size of those of an ordinary clock.
_Curious Experiment with a Tulip._
The bulb of a tulip in every respect resembles buds, except in their being produced under ground, and include the leaves and flower in miniature, which are to be expanded in the ensuing spring. By cautiously cutting in the early spring, through the concentric coats of a tulip root, longitudinally from the top to the base, and taking them off successively, the whole flower of the next summer's tulip is beautifully seen by the naked eye, with its petals, pistal, and stamina.
_The Travelling of Sound experimentally proved._
There is probably no substance which is not in some measure a conductor of sound; but sound is much enfeebled by passing from one medium to another. If a man, stopping one of his ears with his finger, stop the other also by pressing it against the end of a long stick, and a watch be applied to the opposite end of the stick, or a piece of timber, be it ever so long, the beating of the watch will be distinctly heard; whereas, in the usual way, it can scarcely be heard at the distance of fifteen or eighteen feet. The same effect will take place if he stops both his ears with his hands, and rest his teeth, his temple, or the gristly part of one of his ears against the end of a stick. Instead of a watch, a gentle scratch may be made at one end of a pole or rod, and the person who keeps his ear in close contact with the other end of the pole, will hear it very plainly. Thus, persons who are dull of hearing, may, by applying their teeth to some part of a harpsichord, or other sounding body, hear the sound much better than otherwise.
If a person tie a strip of flannel about a yard long, round a poker, then press with his thumbs and fingers the ends of the flannel into his ears, while he swings the poker against an iron fender, he will hear a sound very like that of a large church bell.
_To produce Metallic Lead from the Powder._
Take one ounce of red lead, and half a drachm of charcoal in powder, incorporate them well in a mortar, and then fill the bowl of a tobacco-pipe with the mixture. Submit it to an intense heat, in a common fire, and when melted, pour it out upon a slab, and the result will be metallic lead completely revived.
_To diversify the Colours of Flowers._
Fill a vessel of what size or shape you please, with good rich earth, which has been dried and sifted in the sun, then plant in the same a slip or branch of a plant bearing a white flower, (for such only can be tinged,) and use no other water to water it with, but such as is tinged with red, if you desire red flowers; with blue, if blue flowers, &c. With this coloured water, water the plant twice a day, morning and evening, and remove it into the house at night, so that it drink not of the morning or evening dew for three weeks. You will then experience, that it will produce flowers, not altogether tinctured with that colour wherewith you watered it, but partly with that, and partly with the natural.
_How far Sound travels in a Minute._
However it may be with regard to the theories of sound, experience has taught us, that it travels at about the rate of 1142 feet in a second, or nearly thirteen miles in a minute. The method of calculating its progress is easily made known: when a gun is discharged at a distance, we see the fire long before we hear the sound; if, then, we know the distance of the place, and know the time of the interval between our first seeing the fire, and then hearing the report, this will show us exactly the time the sound has been travelling to us. For instance, if the gun be discharged a mile off, the moment the flash is seen I take a watch and count the seconds till I hear the sound; the number of seconds is the time the sound has been travelling a mile.
_Easy Method of making a Rain Gauge._
A very simple rain gauge, and one which will answer all practical purposes, consists of a copper funnel the area of whose opening is exactly ten square inches: this funnel is fixed in a bottle, and the quantity of rain caught is ascertained by multiplying the weight in ounces by 173, which gives the depth in inches and parts of an inch. In fixing these gauges, care must be taken that the rain may have free access to them: hence the tops of buildings are usually the best places. When the quantities of rain collected in them at different places are compared, the instruments ought to be fixed at the same heights above the ground at both places, because at different heights the quantities are always different, even at the same place.
_To make beautiful Transparent coloured Water._
The following liquors, which are coloured, being mixed, produce colours very different from their own. The yellow tincture of saffron, and the red tincture of roses, when mixed, produce a green. Blue tincture of violets, and brown spirit of sulphur, produce a crimson. Red tincture of roses, and brown spirits of hartshorn, make a blue. Blue tincture of violets, and blue solution of copper, give a violet colour. Blue tincture of cyanus, and blue spirit of sal-ammoniac coloured, make green. Blue solution of Hungarian vitriol, and brown ley of potash, make yellow. Blue solution of Hungarian vitriol, and red tincture of roses, make black; and blue tincture of cyanus, and green solution of copper, produce red.
_Curious Experiment on Rays of Light._
That the rays of light flow in all directions from different bodies, without interrupting one another, is plain from the following experiment:--Make a little hole in a thin plate of metal, and set the plate upright on a table, facing a row of lighted candles standing near together; then place a sheet of paper or pasteboard at a little distance from the other side of the plate; and the rays of all the candles, flowing through the hole, will form as many specks of light on the paper as there are candles before the plate; each speck as distinct and large as if there were only one candle to cast one speck; which shows that the rays do not obstruct each other in their motions, although they all cross in the same hole.
_The Power of Water._
Let a strong small iron tube of twenty feet in height be inserted into the bung-hole of a cask, and the aperture round so strongly closed, that it shall be water-tight; pour water into the cask till it is full, through the pipe; also continue filling the pipe till the cask bursts, which will be when the water is within a foot of the top of the tube. In this experiment the water, on bursting the vessel, will fly about with considerable violence.
_The Pressure of Water._
The pressure of water may be known to every one who will only take the trouble to look at the cock of a water-butt when turned: if the tub or cistern be full, the water runs with much greater velocity through the cock, and a vessel will be filled from it in a shorter time than when it is only half-full, although the cock, in both cases, is equally replete with the fluid during the time the vessel is filling. From this also is understood, how a hole or leak, near the keel of a ship, admits the water much quicker, and with greater violence, than one of the same size near what the mariners call the water's edge.
_Refraction of Light._
In the middle of an empty basin put a piece of money, and then retire from it till the edge of the basin hides the piece from your sight: then keep your head steady, let another person fill the basin gently with water; as the water rises in the basin the money will come in view; and when of a sufficient height in the basin, the whole of the piece will be in sight.
_Wonderful Nature of Lightning._
If two persons, standing in a room, looking different ways, and a loud clap of thunder, accompanied with zigzag lightning, happen, they will both distinctly see the flash at the same time; not only the illumination, but the very form of the lightning itself, and every angle it makes in its course will be as distinctly perceptible, as though they had both looked directly at the cloud from whence it proceeded. If a person happened at that time to be looking on a book, or other object, which he held in his hand, he would distinctly see the form of the lightning between him and the object at which he looked. This property seems peculiar to lightning, as it does not apply to any other kind of fire whatever.
_To show that the White of Eggs contains an Alkali._
Add to a wine-glass half full of tincture of red cabbage a small quantity of the white of an egg, either in a liquid state or rendered concrete by boiling. The tincture will lose its blue colour and become changed to green, because the white of the egg contains soda.
_Two Inodorous Bodies become very Pungent and Odorous by Mixture._
When equal parts of muriate of ammonia and unslaked lime, both substances destitute of odour, are intimately blended together in a mortar, a very pungent gas (ammonia) becomes evolved.
_Interesting Experiment for the Microscope._
The embryo grain of wheat, at the time of blossoming, being carefully taken out of the husk, will be found to have a small downy tuft at its extremity, which, when viewed in a microscope, greatly resembles the branches of thorn, spreading archwise, in opposite directions. By expanding a few of the grains, and selecting the most perfect, a very pretty microscopic object will be obtained for preservation.
_The Travelling of Light._