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, 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at the instant, which will cease as soon as the poker is withdrawn, and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 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 a bluish-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
white appearance. 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 of glass. 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 lines will disappear; 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
become _crystallized_, 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.
EXPERIMENT NO. 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.
EXPERIMENT NO. 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 in the cup over the
lamp, salt of strontium instead 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 will
lose all 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.
[Illustration]
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 Potash Pale violet.
Muriate of Lime Brick red.
Muriate of Strontia Bright crimson.
Muriate of Lithia Red.
Muriate of Baryta Pale apple-green.
Muriate of Copper Bluish green.
Borax Green.
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.