under-surface. There it will be found to have assumed a very different
form, owing to the exclusion of the air, and consequent slower cooling.
Large six-sided crystals, transparent, and of a most exquisitely
delicate yellow, will be seen, piled on one another as appear the
masses of ore in rocks.
Nature always works in such cases on such a gigantic scale that it
seems at first difficult to believe that such huge piles as the Giant’s
Causeway in Ireland, or Fingals in Scotland, or the lodes of tin ore in
Cornwall, worked by the Phœnicians three thousand years ago, and still
being worked, were all formed by the same process.
The time that the earth must have taken to cool fairly staggers the
imagination, yet it is only from guessing, by means of such a study as
this, that geologists are able to form any idea of how long ago it was
that the earth’s crust became cool enough to allow animal and plant
life to exist upon it.
The most beautiful crystalline form is perhaps the diamond, and yet
this precious gem is but the same thing, chemically, as charcoal.
Charcoal is pure carbon in the uncrystallized state, which the magic
of crystallization has transformed into the symbol of all that is
brilliant and beautiful.
Beauties of Crystallization.
Dissolve alum in hot water until no more can be dissolved in it; place
in it a smooth glass rod and a stick of the same size. Next day the
stick will be found covered with crystals, but the glass rod will be
free from them. In this case the crystals cling to the rough surface of
the stick, but have no hold upon the smooth surface of the glass rod.
But if the rod be roughened with a file at certain intervals, and then
placed in the alum and water, the crystals will adhere to the rough
surfaces, and leave the smooth bright and clear.
Tie some threads of lamp-cotton irregularly around a copper wire or
glass rod. Place it in a hot solution of blue vitriol, strong as above,
and the threads will be covered with beautiful blue crystals, while the
glass rod will be bare.
Bore a hole through a piece of coke, and suspend it by a string from a
stick placed across a hot solution of alum. It will float. But as it
becomes loaded with crystals it will sink in the solution according to
the length of the string. Gas-coke has mostly a smooth, shining, and
almost metallic surface, which the crystals will avoid, while they will
cling only to the most irregular and porous parts.
If powdered turmeric be added to the hot solution of alum the crystals
will be of a bright yellow. Litmus will cause them to be of a bright
red. Logwood will yield purple; and common writing ink, black. And the
more muddy the solution the finer will be the crystals.
To keep colored alum crystals from breaking or losing their color,
place them under a glass shade with a saucer of water.
This will preserve the atmosphere moist, and prevent the crystals
getting too dry.
If crystals be formed on wire they will be liable to break off, from
the expansion and contraction of the wire by changes of temperature.
To Crystallize Camphor.
Dissolve camphor in spirit of wine, moderately heated, until the
spirit will not dissolve any more; pour some of the solution into a
cold glass, and the camphor will instantly crystallize in beautiful
tree-like forms, such as we see in the show-glasses of camphor in
druggists’ windows.
ANOTHER EXPERIMENT.
Heat some blue vitriol (sulphate of copper) in an iron ladle till
all the water contained in the crystals is driven off, and the color
changes to a gray. Take the lumps out without breaking them, and
lay the dried blue vitriol on a plate. If this be moistened with
water steam is produced; and if a slice of phosphorus is then laid
on the sulphate of copper it ignites, demonstrating again that the
condensation of a liquid produces heat. The addition of the water
restores the blue color, thus proving that water was necessary to the
composition of blue vitriol.
A Solid Changed to a Liquid.
Mix five parts by weight of powdered sal ammoniac, five parts of nitre
in powder, and sixteen parts of water. A temperature of twenty-two
degrees below the freezing point of water is produced; and if a phial
of water, or any convenient metallic cylinder containing water, be
surrounded with a sufficient quantity of the freezing mixture, ice is
formed. The ice clings to the interior of the tube, but may easily be
removed by dipping it in tepid water.
This experiment is the reverse of the last and proves that the sudden
reduction of a solid to the liquid condition always affords cold.
An amusing combination of two experiments may be made by putting some
fresh-burned lime into one tea pot and this freezing mixture into
another. When water is poured on the one containing lime, it gives
out steam from the spout, while the addition of water to the other
produces so much cold that it can hardly be kept in the hand. Thus heat
and cold are afforded through the same medium, water.
Magic of Heat.
Melt a small quantity of the sulphate of potash and copper in a spoon
over a spirit lamp. It will be fused at a heat just below redness,
and produce a liquid of a dark-green color. Remove the spoon from the
flame, when the liquid will become a solid of a brilliant emerald green
color, and so remain until its heat sinks nearly to that of boiling
water, when suddenly a commotion will take place throughout the mass,
beginning from the surface, and each atom, as if animated, will start
up and separate itself from the rest, till in a few moments the whole
will become a heap of powder.
Sublimation by Heat.
Provide two small pieces of glass; sprinkle a minute portion of
sulphur upon one piece, lay thin slips of wood around it, and place
upon it the other piece of glass. Move them slowly over the flame of a
lamp or candle, and the sulphur will become sublimed, and form gray,
nebulous patches, which are very curious microscopic objects. Each
cluster consists of thousands of transparent globules, imitating in
miniature the nebulæ which we see figured in treatises on astronomy.
By observing the largest particles we shall find them to be flattened
on one side. Being very transparent, each of them acts the part of
a little lens, and forms in its focus the image of a distant light,
which can be perceived even in the smaller globules, until it vanishes
from minuteness. If they are examined again after a certain number of
hours, the smaller globules will generally be found to have retained
their transparency, while the larger ones will have become opaque, in
consequence of the sulphur having undergone some internal spontaneous
change. But the most remarkable circumstance attending this experiment
is that the globules are found adhering to the upper glass only;
the reason of which is that the upper glass is somewhat cooler than
the lower one, by which means we see that the vapor of sulphur is
very powerfully repelled by heated glass. The flattened form of the
particles is owing to the force with which they endeavor to recede from
the lower glass, and their consequent pressure against the surface of
the upper one. This experiment is considered by its originator, Mr.
H. F. Talbot, to be a satisfactory argument in favor of the repulsive
power of heat.
Heat Passing Through Glass.
Although glass is a bad conductor it yet allows heat to pass through
it, and the purer the glass the more easy is this done. Heat a poker
red hot, and having opened a window, apply the poker very near to
the outside of the 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. 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 potash 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 fire a set of polished fire-irons, and beside them a
rough, unpolished poker, such as is used in the 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.
The Alchemist’s Ink.
Dissolve in water a small quantity, about as much as will lay on a
ten-cent piece, of chloride of cobalt, which is of a bluish-green
color, and the solution will be pink; write with it and the characters
will scarcely be 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.
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.
Magic Dyes.
Dissolve indigo in diluted sulphuric acid, and add to it an equal
quantity of solution of carbonate of potash. 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; distill in
a retort, when a spirit will arise, which may be inflamed.
The Chemistry of Water.
More than two-thirds of the earth’s surface is water, so that in mere
quantity alone it is the most important substance with which we are
acquainted. Without it life would be impossible, for, owing to its
quality of dissolving other bodies, it may be regarded as the great
purifier, as well as the vehicle which brings nourishment to plants and
animals alike.
Not only is water useful, but is among the most beautiful of Nature’s
products. It has carved the valleys between mountain ranges by its slow
dropping for ages, and has made the fairy glens by rushing down their
sides in torrents. The stately rivers and the roaring oceans are but
forms of its might.
In another state it works out those fantastic grottoes, mountains and
fields of glittering white, that make the Polar seas the very head
center of dreamland.
In still another form it paints the rainbow in the sky, and hangs like
a veil over the landscape, passing from the most delicate blue over the
plain to the deep purple clinging to distant hills.
To it the golden and red hues of sunrise and sunset are due. The light
fleecy clouds that speak the beauty of spring, and the great thunder
stocks that gleam, with lightning flashes are all composed of water,
and water alone.
It drives our engines and machinery, and speeds our ships across the
sea. Neither is it confined to this earth alone, for astronomers tell
us that vast seas and even clouds can be seen on the next great planet
to the earth, Mars.
Surely, then, as this wondrous substance is examined, the ancients can
be excused for worshiping the ocean as a god, and the old alchemists
for believing it to be an element.
Nevertheless, water is not a simple substance. It is composed of two
gases, which must be combined before water is produced. These gases are
oxygen and hydrogen. Every atom of water consists of one part of the
former gas and two parts by volume of the latter. This you may prove in
the following way:
Buy a piece of sodium, a metal that must not be touched with the
fingers, and thrust it into a small one-ounce jar half full of water;
cork the jar tightly.
Through a hole in the cork pass a glass tube, the outer end being drawn
in a flame to a fine point. Apply a light at the end of the tube. The
escaping gas will catch fire and burn with a light blue flame. This gas
is hydrogen.
Next empty the jar and fill with warm water, and place by means of
another cork a small glass jar on to the tube. Into the lower jar drop
a piece of blazing hot platinum. Repeat this again and again with the
same piece of platinum, being careful not to uncork the upper jar, so
that every time the metal is dropped into the lower jar, you remove
the upper jar with the tube and two corks. After doing this a dozen
times or more take a match that is still glowing after having been
extinguished, and plunge it into the upper jar. It will burst into
flame immediately, and the gas in the upper jar is oxygen.
Two Bitters Make a Sweet.
It has been discovered that a mixture of nitrate of silver with
hyposulphite 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 alteration 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 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.
Restoration of Color by Water.
Water being a colorous 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.
Two Liquids Make a Solid.
Dissolve chloride 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.
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.
To Make Ice.
Although this trick is performed by means of chemicals, yet its product
is obtained really by the use of mechanical laws. We must remember that
ice is exactly the same thing as water so far as its composition is
concerned, differing only in its state of density.
Ice, water, and steam differ in density through the possession of a
greater or less quantity of heat. Hence, the turning of water into ice
really is a case of the operation of mechanical laws.
Now for the experiment. Put into a wide-mouthed jam-jar a smaller
glass vessel containing the water to be frozen. Around the latter put
a mixture of sulphate of soda (Glauber’s salt) and hydrochloric acid
(spirits of salts). The proportions must be eight parts of the former
to five of the latter.
The action of these two chemicals on one another is to cause a cold of
fifteen to seventeen degrees below zero, or forty-seven degrees below
freezing point.
The same result may be obtained by mixing equal parts of nitrate of
ammonia and water. In winter-time when the snow is on the ground, with
a mixture of one part snow and one part common table salt an intense
cold of twenty degrees below zero is obtained.
From this last fact we see how stupid are those people who sprinkle the
salt on the pavements to get rid of the snow. True, the latter melts,
but only after the production of intense cold, which is the cause of
many diseases, not only slight ones like colds and chilblains, but too
often the forerunners of consumption and other lung troubles.
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.
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 the color of port wine; and this
tint, by the addition of potash may be changed to green or yellow.
Changes of the 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.
Marking Indelibly.
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 to a dark room, and they will not change; but expose them to
a strong light, and they will be of an indelible black.
Visible Growth.
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 it 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 will
hang from the acorn in a drop, the skin will burst, and the root will
protrude and thrust itself in 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:
Chloride of Soda (common salt) Yellow.
“ of Potash Pale violet.
“ of Lime Brick red.
“ of Strontia Bright crimson.
“ of Lithia Red.
“ of Baryta Apple green.
“ of Copper Bluish green.
Borax Yellow.
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 silver.
INSTANTANEOUS FLAME.
Heat together potassium and sulphur, and they will instantly burn very
vividly.