with water, place it in the receiver. The air being exhausted, the
spring of that which is in the pores of the solid body, by expanding
the particles, will make them rise on its surface in numberless
globules, which resemble the pearly drops of dew on the tops of the
grass. The effect ceases when the air is let into the receiver.
_The floating Stone._
To a piece of cork tie a small stone that will just sink it; and,
putting it in a vessel of water, place it under the receiver. Then
exhausting the receiver, the bubbles of air will expand from its
pores, and, adhering to its surface, will render it, together with the
stone, lighter than water, and consequently they will rise to the
surface, and float.
_Withered Fruit restored._
Take a shrivelled apple, and, placing it under the receiver, exhaust
the air. The apple will immediately be plumped up, and look as fresh
as when first gathered: for this reason, that the pressure of the
external air being taken off, the air in the apple extends it, so much
indeed that it will sometimes burst. If the air be let into the
receiver, the apple will be restored to its pristine shrivelled state.
_Vegetable Air-Bubbles._
Put a small branch of the tree with its leaves, or part of a small
plant, in a vessel of water, and, placing the vessel in the receiver,
exhaust the air.
When the pressure of the external air is taken off, the spring of that
contained in the air-vessels of the plant, by expanding the particles,
will make them rise from the orifices of all the vessels for a long
time together, and produce a most beautiful appearance.
_The Mercurial Wand._
Take a piece of stick, cut it even at each end with a penknife, and
immerse it in a vessel of mercury. When the air is pumped out of the
receiver, it will at the same time come out of the pores of the wood,
through the mercury, as will be visible at each end of the stick. When
the air is again let into the receiver, it falls on the surface of the
mercury, and forces it into the pores of the wood, to possess the
place of the air.
When the rod is taken out, it will be found considerably heavier than
before, and that it has changed its colour, being now all over of a
bluish hue. If cut transversely, the quicksilver will be seen to
glitter in every part of it.
_The Magic Bell._
Fix a small bell to the wire that goes through the top of the
receiver. If you shake the wire, the bell will ring while the air is
in the receiver; but when the air is drawn off, the sound will by
degrees become faint, till at last not the least noise can be heard.
As you let the air in again, the sound returns.
_Feathers heavier than Lead._
At one end of a fine balance, hang a piece of lead, and at the other
as many feathers as will poise it; then place the balance in the
receiver. As the air is exhausted, the feathers will appear to
overweigh the lead, and when all the air is drawn off, the feathers
will preponderate, and the lead ascend.
_The self-moving Wheel._
Take a circle of tin, about ten inches in diameter, or of any other
size that will go into the receiver, and to its circumference fix a
number of tin vanes, each about an inch square. Let this wheel be
placed between two upright pieces on an axis, whose extremities are
quite small, so that the wheel may turn in a vertical position with
the least possible force. Place the wheel and axis in the receiver,
and exhaust the air. Let there be a small pipe with a cock; one end of
the pipe to be outside the top of the receiver, and the other to come
directly over the vanes of the wheel.
When the air is exhausted, turn the cock, and a current will rush
against the vanes of the wheel, and set it in motion, which will
increase, till the receiver is filled with air.
_The Artificial Halo._
Place a candle on one side of the receiver, and let the spectator
place himself at a distance from the other side. Directly the air
begins to be exhausted, the light of the candle will be refracted in
circles of various colours.
_The Mercurial Shower._
Cement a piece of wood into the lower part of the neck of an open
receiver, and pour mercury over it. After a few strokes of the pump,
the pressure of the air on the mercury will force it through the pores
of the wood in the form of a beautiful shower. If you take care that
the receiver is clear and free from spots or dust, and it is dry
weather, it will appear like a fiery shower, when exhibited in a dark
room.
_Magic Fountain._
Take a tall glass tube, hermetically sealed both at top and bottom, by
means of a brass cap screwed on to a stop-cock, and place it on the
plate of the pump. When the air is exhausted, turn the cock, take the
tube off the plate, and plunge it into a basin of mercury or water.
Then the cock being again turned, the fluid, by the pressure of the
air, will play upon the tube in the form of a beautiful fountain.
_The Exploded Bladder._
Take a glass pipe open at both ends, to one of which tie fast a wet
bladder, and let it dry. Then place it on the plate of the pump. While
the air presses the bladder equally on both sides, it will lie even
and straight; but as soon as the air is exhausted, it will press
inwards, and be quite concave on the upper side. In proportion as the
air is exhausted, the bladder will become more stretched; it will soon
yield to the incumbent pressure, and burst with a loud explosion. To
make this experiment more easy, one part of the bladder should be
scraped with a knife, and some of its external fibres taken off.
_The Cemented Bladder._
Tie the neck of the bladder to a stop-cock, which is to be screwed to
the plate of the pump, and the air exhausted from the bladder; then
turn the stop-cock, to prevent the re-entrance of the air, and unscrew
the whole from the pump. The bladder will be transformed into two flat
skins, so closely applied together, that the strongest man cannot
raise them half an inch from each other; for an ordinary-sized
bladder, of six inches across the widest part, will have one side
pressed upon the other with a force equal to 396 pounds' weight.
_Cork heavier than Lead._
Let a large piece of cork be pendent from one end of a balance beam,
and a small piece of lead from the other; the lead should rather
preponderate. If this apparatus be placed under a receiver on the
pump, you will find that when the air is exhausted, the lead, which
seemed the heaviest body, will ascend, and the cork outweigh the lead.
Restore the air, and the effect will cease. This phenomenon is only on
account of the difference of the size in the two objects. The lead,
which owes its heaviness to the operation of the air, yields to a
lighter because a larger substance when deprived of its assistance.
_The animated Bacchus._
Construct a figure of Bacchus, seated on a cask; let his belly be
formed by a bladder, and let a tube proceed from his mouth to the
cask. Fill this tube with coloured water or wine, then place the whole
under the receiver. Exhaust the air, and the liquor will be thrown up
into his mouth. While he is drinking, his belly will expand.
_The Artificial Balloon._
Take a bladder containing only a small quantity of air, and a piece of
lead to it, sufficient to sink it, if immersed in water. Put this
apparatus into a jar of water, and place the whole under a receiver.
Then exhaust the air, and the bladder will expand, become a balloon
lighter than the fluid in which it floats, and ascend, carrying the
weight with it.
_Curious Experiments with a Viper._
Many natural philosophers, in their eagerness to display the powers of
science, have overlooked one of the first duties of life, humanity;
and, with this view, have tortured and killed many harmless animals,
to exemplify the amazing effects of the air-pump. We, however, will
not stain the pages of this little work by recommending any such
species of cruelty, which in many instances can merely gratify
curiosity; but as our readers might like to read the effect on
animals, we extract from the learned Boyle an account of his
experiment with a viper.
He took a newly-caught viper, and, shutting it up in a small receiver,
extracted the air. At first, upon the air being drawn away, the viper
began to swell; a short time after it gasped and opened its jaws; it
then resumed its former lankness, and began to move up and down within
the receiver, as if to seek for air. After a while, it foamed a
little, leaving the foam sticking to the inside of the glass; soon
after, the body and neck became prodigiously swelled, and a blister
appeared on its back. Within an hour and a half from the time the
receiver was exhausted, the distended viper moved, being yet alive,
though its jaws remained quite stretched; its black tongue reached
beyond the mouth, which had also become black in the inside: in this
situation it continued for three hours; but on the air being
re-admitted, the viper's mouth was presently closed, and soon after
opened again; and these motions continued some time, as if there were
still some remains of life.
It is thus with animals of every kind; even minute microscopical
insects cannot live without air.
_Experiments with Sparrows._
Count Morozzo placed successively several full-grown sparrows under a
glass receiver, inverted over water. It was filled with atmospheric
air, and afterwards with vital air. He found,
First.--That in _atmospheric_ air, HOURS MIN.
The first sparrow lived 3 0
The second sparrow lived 0 3
The third sparrow lived 0 1
The water rose in the vessels eight lines during the life of the
first; four during the life of the second; and the third produced no
absorption.
Second.--In _vital_ air or _oxygen_, HOURS MIN.
The first sparrow lived 5 23
The second 2 10
The third 1 30
The fourth 1 10
The fifth 0 30
The sixth 0 47
The seventh 0 27
The eighth 0 30
The ninth 0 22
The tenth 0 21
The above experiments elicit the following conclusions:--1. That an
animal will live longer in vital than in atmospheric air.--2. That one
animal can live in air, in which another has died.--3. That,
independently of air, some respect must be had to the constitution of
the animal; for the sixth lived 47 minutes, the fifth only thirty.--4.
That there is either an absorption of air, or the production of a new
kind of air, which is absorbed by the water as it rises.
AMUSING EXPERIMENTS IN ELECTRICITY.
_The Animated Feather._
Electrify a smooth glass tube with a rubber, and hold a small feather
at a short distance from it. The feather will instantly fly to the
tube, and adhere to it for a short time; it will then fly off, and the
tube can never be brought close to the feather till it has touched the
side of the room, or some other body that communicates with the
ground. If, therefore, you take care to keep the tube between the
feather and the side of the room, you may drive it round to all parts
of the room without touching it; and, what is very remarkable, the
same side of the feather will be constantly opposite the tube.
While the feather is flying before the smooth tube, it will be
immediately attracted by an excited rough tube or a stick of wax, and
fly continually from one tube to the other, till the electricity of
both is discharged.
_The Candle lighted by Electricity._
Charge a small coated phial, whose knob is bent outwards so as to hang
a little over the body of the phial; then wrap some loose cotton over
the extremity of a long brass pin or wire, so as to stick moderately
fast to its substance. Next roll this extremity of the pin, which is
wrapped up in cotton, in some fine powdered resin; then apply the
extremity of the pin or wire to the external coating of the charged
phial, and bring, as quickly as possible, the other extremity, that is
wrapped round with cotton, to the knob; the powdered resin takes fire,
and communicates its flame to the cotton, and both together burn long
enough to light a candle. Dipping the cotton in oil of turpentine will
do as well, if you use a larger sized jar.
_Candle Bombs._
Procure some small glass bubbles, having a neck about an inch long,
with very slender bores, by means of which a small quantity of water
is to be introduced into them, and the orifice afterwards closed up.
This stalk being put through the wick of a burning candle, the flame
boils the water into a steam, and the glass is broken with a loud
explosion.
_The Artificial Spider._
Cut a piece of burnt cork, about the size of a pea, into the shape of
a spider; make its legs of linen thread, and put a grain or two of
lead in it to give it more weight. Suspend it by a fine line of silk
between an electrified arch and an excited stick of wax; and it will
jump continually from one body to the other, moving its legs at the
same time, as if animated, to the great surprise of the unconscious
spectator.
_The Miraculous Portrait._
Get a large print (suppose of the king) with a frame and glass. Cut
the print out at about two inches from the frame all round; then with
thin paste fix the border that is left on the inside of the glass,
pressing it smooth and close; fill up the vacancy, by covering the
glass well with leaf-gold or thin tin-foil, so that it may lie close.
Cover likewise the inner edge of the bottom part of the back of the
frame with the same tin-foil, and make a communication between that
and the tin-foil in the middle of the glass; then put in the board,
and that side is finished. Next turn up the glass, and cover the
fore-side with tin-foil, exactly over that on the back part; and when
it is dry, paste over it the panel of the print that was cut out,
observing to bring the corresponding parts of the border and panel
together, so that the picture will appear as at first, only part of it
behind the glass, and part before. Lastly, hold the print horizontally
by the top, and place a little moveable gilt crown on the king's head.
Now, if the tin-foil on both sides of the glass be moderately
electrified, and another person take hold of the bottom of the frame
with one hand, so that his fingers touch the tin-foil, and with the
other hand attempt to take off the crown, he will receive a very smart
blow, and fail in the attempt. The operator, who holds the frame by
the upper end, where there is no tin-foil, feels nothing of the shock,
and can touch the face of the king without danger, which he pretends
is a test of his loyalty.
_The Cup of Tantalus._
You place a cup of any sort of metal on a stool of baked wood or a
cake of wax. Fill it to the brim with any liquor; let it communicate
with the branch by a small chain; and when it is moderately
electrified, desire a person to taste the liquor, without touching the
cup with his hands, and he will instantly receive a shock on his lips.
The motion of the wheel being stopped, you taste the liquor yourself,
and desire the rest of the company to do so; you then give your
operator (who is concealed in an adjoining room) the signal, and he
again charges the cup; you desire the same person to taste the liquor
a second time, and he will receive a second shock.
_Magical Explosion._
Make up some gunpowder, in the form of a small cartridge, in each end
of which put a blunt wire, so that the ends inside of the cartridge be
about half an inch off each other; then join the chain that proceeds
from one side of the electrifying battery, to the wire at the other
end, the shock will instantly pass through the powder, and set it on
fire.
_Artificial Earthquake._
In the middle of a large basin of water, lay a round wet board. On the
board place any kind of building, made of pasteboard, of separate
pieces, and not fastened together. Then, fixing a wire that
communicates with the two chains of the electrifying battery, so that
it may pass over the board and the surface of the water, upon making
the explosion, the water will become agitated as in an earthquake, and
the board, moving up and down, will overturn the structure, while the
cause of the commotion is totally concealed.
_The Magic Dance._
From the middle of the brass arch suspend three small bells. The two
outer bells hang by chains, and the middle one by a silk string, while
a chain connects it with the floor. Two small knobs of brass, which
serve as clappers, hang by silk strings, one between each two bells.
Therefore, when the two outer bells communicating with the conductor
are electrified, they will attract the clappers and be struck by them.
The clappers being thus loaded with electricity, will be repelled, and
fly to discharge themselves upon the middle bell, after which they
will be again attracted by the outer bells; and thus, by striking the
bells alternately, the ringing may be continued as long as the
operator pleases.
You next suspend a plate of metal from the same part of the arch to
which the bells are connected; then, at the distance of a few inches
from the arch, and exactly under it, place a metal stand _of the same
size_. On the stand place several figures of men, animals, or what you
please, cut in paper, and pretty sharply pointed at each extremity.
When the plate that hangs from the arch is electrified, the figures
will dance with astonishing rapidity, and the bells will keep ringing,
to the no small entertainment of the spectators.
_The Electrical Fountain._
Suspend a vessel of water from the middle of the brass arch, and place
in the vessel a small tube. The water will be one continued stream;
and if the electrification be strong, a number of streams will issue,
in form of a cone, the top of which will be at the extremity of the
tube. This experiment may be stopped and renewed almost instantly, as
if at the word of command.
_The Electric Kite._
Make a small cross of two light strips of cedar, the arms so long as
to reach to the four corners of a large thin silk handkerchief, when
extended; tie the corners of the handkerchief to the extremities of
the cross; and you have the body of the kite, which being properly
accommodated with a tail, loop, and string, will rise in the air like
those made of paper; but this being silk, it is more adapted to bear
the wet and wind of a thunder gust, without tearing. To the top of the
upright stick of the cross is to be fixed a very sharp-pointed wire,
rising a foot or more above the wood. To the end of the twine is to be
tied a silk ribbon, and where the silk and twine join, a key may be
fastened. This kite is to be raised when a thunder-storm appears to be
coming on; and the person who holds the string must stand within a
door or window, or under some cover, so that the silk ribbon may not
be wet; and care must be taken that the twine do not touch the frame
of the door or window. As soon as any of the thunder clouds come over
the kite, the pointed wire will draw the electric fire from them, and
the kite, with all the twine, will be electrified, while the loose
filaments of the twine will stand out every way, and be attracted by
an approaching finger. When the rain has wetted the kite and twine, so
that it can conduct the electric fire freely, you will find it stream
out plentifully from the key, on the approach of your knuckle. At this
key an electric phial may be charged; and from electric fire thus
obtained, spirits may be kindled, and all the other electric
experiments performed which are usually done by the help of a rubbed
glass or tube; and thereby the identity of the electric matter with
that of lightning completely demonstrated.
_The Magic Chase._
On the top of a finely-pointed wire, rising perpendicularly from the
conductor, let another wire, sharpened at each end, be made to move
freely, as on a centre. If it be well balanced, and the points bent
horizontally, in opposite directions, it will, when electrified, turn
very swiftly round, by the re-action of the air against the current
which flows from off the points. These points may be nearly concealed,
and the figures of men and horses, with hounds, and a hare, stag, or
fox, may be placed upon the wires, so as to turn round with them, when
they appear as if in pursuit. The chase may be diversified, and a
greater variety of figures upon them, by increasing the number of
wires proceeding from the same centre.
_The Unconscious Incendiary._
Let a person stand upon a stool made of baked wood, or upon a cake of
wax, and hold a chain which communicates with the branch. On turning
the wheel he will become electrified; his whole body forming part of
the prime conductor; and he will emit sparks whenever he is touched by
a person standing on the floor.
If the electrified person put his finger, or a rod of iron, into a
dish containing warm spirits of wine, it will be immediately in a
blaze; and if there be a wick or thread in the spirit, that
communicates with a train of gunpowder, he may be made to blow up a
magazine, or set a city on fire, with a piece of cold iron, and at the
same time be ignorant of the mischief he is doing.
_The Inconceivable Shock._
Put in a person's hand a wire that is fixed on to the hook that comes
from the chain, which communicates with one side of the battery, and
in his other hand put a small wire with a hook at the end of it, which
you direct him to fix on to a hook which comes from the other chain.
On attempting to do this, he will instantly receive a shock from his
body, without being able to guess the cause.
Care should be taken that the shock be not too strong; and regard
should be had to the constitution and disposition of the party, as a
shock that would hardly affect one person, might be productive of
very serious consequences to another.
Much entertainment may be derived from concealing the chain that
communicates with that which proceeds from the outside of the battery,
under a carpet, and placing the wire that communicates with the chain
from the inside, in such a manner that a person may put his hand on it
without suspicion, at the same time that his feet are upon the other
wire.
The whole company may be made to partake of the shock, by joining
hands, and forming a circle. The experiment may also be varied if they
tread upon each other's toes, or lay their hands upon each other's
heads. It might happen, by the latter method, that the whole company
would be struck to the ground; but it will be productive of no danger,
and very little inconvenience; on the contrary, it has happened that
they have neither heard nor felt the shock.
* * * * *
To exhibit the five following amusements in electricity, the room in
which they are performed must be darkened.
_The Miraculous Luminaries._
You must previously prepare the following phosphorus: Calcine common
oyster-shells, by burning them in the fire for half an hour; then
reduce them to powder; of the clearest of which take three parts, and
of flowers of sulphur one part; put the mixture into a crucible, about
an inch and a half deep. Let it burn in a strong fire for rather
better than an hour; and when it is cool, turn it out and break it in
pieces; and, taking those pieces into a dark place, scrape off the
parts that shine brightest, which, if good, will be a white powder.
Then construct a circular board, of three or four feet diameter, on
the centre of which draw in gum-water, or any adhesive liquid, a
half-moon, of three or four inches diameter, and a number of stars
round it, at different distances, and of various magnitudes. Strew the
phosphorus over the figures, to the thickness of about a quarter of an
inch, laying one coat over the other. Place this board behind a
curtain; and when you draw the curtain up or back, discharge one
electrifying jar or phial over each figure, at the distance of about
an inch, and they will become illuminated, exhibiting a very striking
resemblance of the moon and stars; and will continue to shine for
about half an hour, their splendour becoming gradually more faint.
_The Fiery Shower._
On the plate put a number of any kind of seeds, grains of sand, or
brass dust. The conductor being strongly electrified, those light
particles will be attracted and repelled by the plate suspended from
the conductor, with amazing rapidity, so as to exhibit a perfect fiery
shower.
Another way is by a sponge that has been soaked in water. When this
sponge is first hung to the conductor, the water will drop from it
very slowly; but when it is electrified, the drops will fall very
fast, and appear like small globes of fire, illuminating the basin
into which they fall.
_The Illuminated Vacuum._
Take a tall receiver that is very dry, and fix through the top of it,
with cement, a blunt wire; then exhaust the receiver, and present the
knob of the wire to the conductor, and every spark will pass through
the vacuum in a broad stream of light, visible through the whole
length of the receiver, let it be as tall as it will. This generally
divides into a variety of beautiful rivulets, which are continually
changing their course, uniting and dividing again in the most pleasing
manner.