Part 13

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 find _warmth_ in one hand and _cold_ in 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 the _same_ time.

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 or two 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 a handle 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 rise in 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 of troubled 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 a _lunar_, 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 over a 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 of _litmus_. 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 test_ of 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 to _test_ any fluid, to ascertain if it has an _acid_ reaction. 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 is _alkaline_, 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.

INFINITE DIVISIBILITY OF MATTER.

Dissolve a single grain of copper in about one dram of nitric acid, and dilute the solution with about one ounce of water, when it will be evident that a single drop of the mixture must contain an almost immeasurably small portion of copper. Yet, if the blade of a knife be dipped into it, it will become covered with a coat of copper; thus showing that the copper can be infinitely divided without any alteration in its properties.

FOOTNOTES:

[Footnote 4: See also page 84.]

[Footnote 5: All experiments marked thus, *, should be performed on the hob of the grate, to permit the fumes to escape up the chimney.]

AMUSEMENTS

IN

ELECTRICITY, GALVANISM AND MAGNETISM.

THE ORIGIN OF GALVANISM.

Electricity is one of the most active principles in nature. It exists in all bodies, and is exhibited by various means, one of which, and the most generally employed, is friction; but the bodies rubbed together must consist of different substances; for, if they are alike, electricity will not be evolved. Some substances, such as soot, charcoal, iron, gold, silver, copper, and other metals, water, &c., are called _good conductors_, because they transfer with great facility to other bodies the electric fluid, which glides over the surface with the velocity of light; while others, such as silk, wool, hair, feathers, dry paper, leather, glass, wax, &c., are called _non-conductors_, because they resist the progress of the fluid, which accumulates all the time the friction continues. It is from these media that are obtained the usual phenomena of electricity, as exhibited in the experiments which we shall hereafter describe. Its effects are felt in almost every part of nature; the awful lightning is the exhibition of the electric fluid, which accumulates in the clouds, and which is discharged when the heavy lurid masses come in contact with each other; the mysterious sweeping whirlwind, the terrific rising and rolling of the sand in the desert wilds of Africa, and the beautiful yet evanescent Aurora Borealis of the northern climes, are amongst a few of its effects.

The next branch of the science of Electricity is GALVANISM, or, as it is sometimes called, Voltaic Electricity; it is obtained through the simple contact of different conducting bodies with each other. It was first discovered at Bologna, in the year 1791, by the lady of Louis Galvani, an Italian philosopher of great merit, and professor of anatomy; from whom, indeed, the science received its name. His wife being possessed of a penetrating understanding, and passionately loving him, took a lively interest in the science which so much occupied his attention. At the time the incident we are about to narrate took place, she was in a declining state of health, and taking soup made of frogs, by way of restorative. Some of these animals, skinned for the purpose, happened to be lying on the table of Galvani's laboratory, where also stood an electrical machine, when the point of a knife was unintentionally brought into contact with the nerves of one of the frog's legs, which lay close to the conductor of the machine, and immediately the muscles of the limb were violently agitated. Madame Galvani having observed the phenomenon, instantly informed her husband of it, and this incident led to the experiments and interesting discoveries which will transmit his name to the latest posterity.

The uses of Galvanic Electricity for scientific purposes are incalculable; and its phenomena are so various and extraordinary, as to render the study of this science exceedingly interesting. Through means of a galvanic battery, substances are decomposed, colors changed, water is made inflammable, and motion is given to lifeless bodies.

The experiments we give on Galvanism show the effect of the combination which forms what is called a simple galvanic circle, by means of two metals, zinc and silver, or zinc and copper, and water.

Galvanic action is always accompanied by chemical action, and all that is necessary to disturb the galvanic fluid is to unite two metals together, and subject them to the action of a fluid, which will act chemically upon one of them, differently to what it does upon the other.

A galvanic circle may also be formed of one metal, and two different fluids, which have a different action upon the metal.

Magnetism is a modification of electricity: at least, there is sufficient evidence that these causes are intimately connected, if not identical; but philosophers are as yet ignorant of its nature.

The property designated by the word magnetism is found in an iron ore of a certain composition, and of a dark gray color and peculiar luster. This ore alone is the local habitation of magnetism, whilst all others are subject to its influence, or to be attracted by it. Still, so little difference is there between the magnetic ore, or loadstone, and those which do not possess the property, that only practiced mineralogists can discern one from the other; and an experienced eye may see two ores join each other by the principle of attraction, without knowing in which resides the power, until another ore, non-magnetic, is brought within the sphere of attraction, when it will adhere only to that which contains the principle.

This singular property of the loadstone is imparted to other metallic substances, by rubbing and keeping them close together for some length of time: if a metal be of a hard texture like steel, it retains the magnetic principle permanently; but if soft, it loses the power as soon as separated from the magnet. The metals thus prepared, acquire the same directive and attractive power as the loadstone or natural magnet, and are employed for purposes of the utmost importance.

We proceed to give the youthful amateur the opportunity of exemplifying the principles of electricity, galvanism, and magnetism, by several simple experiments.

EXPERIMENTS IN ELECTRICITY.

1.--Lay a watch down upon a table, and on its face balance a tobacco-pipe very carefully. Next take a wine-glass, rub it quickly with a silk handkerchief, and hold it for half a minute before the fire; then apply it near to the end of the pipe, and the latter, attracted by the electricity evolved by the friction and warmth in the former, will immediately follow it; and by carrying the glass around, always in front of the pipe, the latter will continue its rotatory motion; the watch-glass being the center or pivot on which it acts.

2.--Warm a glass tube, rub it with a warm flannel, and then bring a downy feather near it. On the first moment of contact, the feather will adhere to the glass, but soon after will fly rapidly from it, and you may drive it about the room by holding the glass between it and the surrounding objects; should it, however, come in contact with anything not under the influence of electricity, it will instantly fly back to the glass.

3.--A stick of sealing-wax rubbed against a warm piece of flannel or cloth, acquires the property of attracting light substances, such as small pieces of paper, lint, &c., if instantly applied at the distance of about an inch.

4.--Suspend two small pith balls, by fine silken threads of about six inches in length, in such a manner, that when at rest they may hang in contact with each other; on applying a piece of sealing wax, excited as in the former experiment, they will repel each other.

5.--Take a piece of common brown paper, about the size of an octavo book, hold it before the fire till quite dry and hot, then draw it briskly under the arm several times, so as to rub it on both sides at once by the coat. The paper will be found so powerfully electrical, that if placed against a wainscoted or papered wall of a room, it will remain there for some minutes without falling.

6.--And if, while the paper adheres to the wall, a light fleecy feather be placed against it, it will be attracted to the paper, in the same way as the paper is attracted to the wall.

7.--If the paper be again warmed, and drawn under the arm as before, and hung up by a thread attached to one corner of it, it will hold up several feathers on each side; should these fall off from different sides at the same time, they will cling together very strongly; and if after a minute they be all shaken off, they will fly to one another in a very singular manner.

8.--Warm and excite the paper as before, lay it on a table, and place upon it a ball made of elder pith, about the size of a pea; the ball will immediately run across the paper, and if a needle be pointed towards it, it will again run to another part, and so on for a considerable time.

9.--Support a pane of glass, previously warmed, upon two books, one at each end, and place some bran underneath; then rub the upper side of the glass with a black silk handkerchief, or a piece of flannel, and the bran will dance up and down under it with much rapidity.