Practical Mechanics for Boys by James Slough Zerbe
CHAPTER XIV
1992 words | Chapter 19
THE SIMPLICITY OF GREAT INVENTIONS, AND OF NATURE'S MANIFESTATIONS
If there is anything in the realm of mechanics which excites the wonder
and admiration of man, it is the knowledge that the greatest inventions
are the simplest, and that the inventor must take advantage of one law
in nature which is universal in its application, and that is vibration.
There is a key to every secret in nature's great storehouse. It is not a
complicated one, containing a multiplicity of wards and peculiar angles
and recesses. It is the very simplicity in most of the problems which
long served as a bar to discovery in many of the arts. So extremely
simple have been some of the keys that many inventions resulted from
accidents.
INVENTION PRECEDES SCIENCE.--Occasionally inventions were brought about
by persistency and energy, and ofttimes by theorizing; but science
rarely ever aids invention. The latter usually precedes science. Thus,
reasoning could not show how it might be possible for steam to force
water into a boiler against its own pressure. But the injector does
this.
If, prior to 1876, it had been suggested that a sonorous vibration could
be converted into an electrical pulsation, and transformed back again to
a sonorous vibration, science would have proclaimed it impossible; but
the telephone does it. Invention shows how things are done, and science
afterwards explains the phenomena and formulates theories and laws which
become serviceable to others in the arts.
SIMPLICITY IN INVENTIONS.--But let us see how exceedingly simple are
some of the great discoveries of man.
THE TELEGRAPH.--The telegraph is nothing but a magnet at each end of a
wire, with a lever for an armature, which opens and closes the circuit
that passes through the magnets and armature, so that an impulse on the
lever, or armature, at one end, by making and breaking the circuit, also
makes and breaks the circuit at the other end.
TELEPHONE.--The telephone has merely a disk close to but not touching
the end of a magnet. The sonorous vibration of the voice oscillates the
diaphragm, and as the diaphragm is in the magnetic field of the magnet,
it varies the pressure, so called, causing the diaphragm at the other
end of the wire to vibrate in unison and give out the same sound
originally imparted to the other diaphragm.
TRANSMITTER.--The transmitter is merely a sensitized instrument. It
depends solely on the principle of light contact points in an electric
circuit, whereby the vibrations of the voice are augmented.
PHONOGRAPH.--The phonograph is not an electrical instrument. It has a
diaphragm provided centrally with a blunt pin, or stylus. To make the
record, some soft or plastic material, like wax, or tinfoil, is caused
to move along so that the point of the stylus makes impressions in it,
and the vibrations of the diaphragm cause the point to traverse a groove
of greater or smaller indentations. When this groove is again presented
to the stylus the diaphragm is vibrated and gives forth the sounds
originally imparted to it when the indentations were made.
WIRELESS TELEGRAPHY.--Wireless telegraphy depends for its action on what
is called induction. Through this property a current is made of a high
electro-motive force, which means of a high voltage, and this disturbs
the ether with such intensity that the waves are sent out in all
directions to immense distances.
The great discovery has been to find a mechanism sensitive enough to
detect the induction waves. The instrument for this purpose is called a
coherer, in which small particles cohere through the action of the
electric waves, and are caused to fall apart mechanically, during the
electrical impulses.
PRINTING TELEGRAPH.--The printing telegraph requires the synchronous
turning of two wheels. This means that two wheels at opposite ends of a
wire must be made to turn at exactly the same rate of speed. Originally,
this was tried by clock work, but without success commercially, for the
reason that a pendulum does not beat with the same speed at the equator,
as at different latitudes, nor at altitudes; and temperature also
affects the rate. The solution was found by making the two wheels move
by means of a timing fork, which vibrates with the same speed
everywhere, and under all conditions.
ELECTRIC MOTOR.--The direct current electric motor depends for its
action on the principle that likes repel, and unlikes attract. The
commutator so arranges the poles that at the proper points, in the
revolution of the armature, the poles are always presented to each other
in such a way that as they approach each other, they are opposites, and
thus attract, and as they recede from each other they repel. A dynamo is
exactly the same, except that the commutator reverses the operation and
makes the poles alike as they approach each other, and unlike as they
recede.
Steel is simply iron, to which has been added a small per cent of
carbon.
Quinine is efficient in its natural state, but it has been made
infinitely more effectual by the breaking up or changing of the
molecules with acids. Sulphate of quinine is made by the use of
sulphuric acid as a solvent.
EXPLOSIONS.--Explosions depend on oxygen. While this element does not
burn, a certain amount of it must be present to support combustion.
Thus, the most inflammable gas or liquid will not burn or explode unless
oxygenized. Explosives are made by using a sufficient amount, in a
concentrated form, which is added to the fuel, so that when it is
ignited there is a sufficient amount of oxygen present to support
combustion, hence the rapid explosion which follows.
VIBRATION IN NATURE.--The physical meaning of vibration is best
illustrated by the movement of a pendulum. All agitation is vibration.
All force manifests itself in this way.
The painful brilliancy of the sun is produced by the rapid vibrations of
the rays; the twinkle of the distant star, the waves of the ocean when
ruffled by the winds; the shimmer of the moon on its crested surface;
the brain in thinking; the mouth in talking; the beating of the heart;
all, alike, obey the one grand and universal law of vibratory motion.
QUALITIES OF SOUND.--Sound is nothing but a succession of vibrations of
greater or less magnitude. Pitch is produced by the number of
vibrations; intensity by their force; and quality by the character of
the article vibrated.
Since the great telephone controversy which took place some years ago
there has been a wonderful development in the knowledge of acoustics, or
sounds. It was shown that the slightest sound would immediately set into
vibration every article of furniture in a room, and very sensitive
instruments have been devised to register the force and quality.
THE PHOTOGRAPHER'S PLATE.--It is known that the chemical action of an
object on a photographer's plate is due to vibration; each represents a
force of different intensity, hence the varying shades produced. Owing
to the different rates of vibrations caused by the different colors, the
difficulty has been to photograph them, but this has now been
accomplished. Harmony, or "being in tune," as is the common expression,
is as necessary in light, as in music.
Some chemicals will bring out or "develop," the pictures; others will
not. Colors are now photographed because invention and science have
found the harmonizing chemicals.
QUADRUPLEX TELEGRAPHY.--One of the most remarkable of all the wonders of
our age is what is known as duplex and quadruplex telegraphy. Every atom
and impulse in electricity is oscillation. The current which transmits
a telegram is designated in the science as "vibratory."
But how is it possible to transmit two or more messages over one wire at
the same time? It is by bringing into play the harmony of sounds. One
message is sent in one direction in the key of A; another message in the
other direction in B; and so any number may be sent, because the
electrical vibrations may be tuned, just like the strings of a violin.
ELECTRIC HARMONY.--Every sound produces a corresponding vibration in
surrounding objects. While each vibrates, or is capable of transmitting
a sound given to it by its vibratory powers, it may not vibrate in
harmony.
When a certain key of a piano is struck every key has a certain
vibration, and if we could separate it from the other sounds, it would
reflect the same sound as the string struck, just the same as the walls
of a room or the air itself would convey that sound.
But as no two strings in the instrument vibrate the same number of times
each second, the rapid movement of successive sounds of the keys do not
interfere with each other. If, however, there are several pianos in a
room, and all are tuned the same pitch, the striking of a key on one
instrument will instantly set in vibration the corresponding strings in
all the other instruments.
This is one reason why a piano tested in a music wareroom has always a
more beautiful and richer sound than when in a drawing-room or hall,
since each string is vibrated by the other instrument.
If a small piece of paper is balanced upon the strings of a violin,
every key of the piano may be struck, except the one in tune, without
affecting the paper; but the moment the same key is struck the vibration
of the harmonizing pitch will unbalance the paper.
The musical sound of C produces 528 vibrations per second; D 616, and so
on. The octave above has double the number of vibrations of the lower
note. It will thus be understood why discord in music is not pleasant to
the ear, as the vibrations are not in the proper multiples.
ODORS.--So with odors. The sense of smell is merely the force set in
motion by the vibration of the elements. An instrument called the
_odophone_ demonstrates that a scale or gamut exists in flowers; that
sharp smells indicate high tones and heavy smells low tones. Over fifty
odors have thus been analyzed.
The treble clef, note E, 4th space, is orange; note D, 1st space below,
violet; note F, 4th space above clef, ambergris. To make a proper
bouquet, therefore the different odors must be harmonized, just the
same as the notes of a musical chord are selected.
A BOUQUET OF VIBRATIONS.--The odophone shows that santal, geranium,
orange flower and camphor, make a bouquet in the key of C. It is easy to
conceive that a beautiful bouquet means nothing more than an agreeable
vibratory sensation of the olfactory nerves.
TASTE.--So with the sense of taste. The tongue is covered with minute
cells surrounded by nervous filaments which are set in motion whenever
any substance is brought into contact with the surface. Tasting is
merely the movement of these filaments, of greater or less rapidity.
If an article is tasteless, it means that these filaments do not
vibrate. These vibrations are of two kinds. They may move faster or
slower, or they may move in a peculiar way. A sharp acute taste means
that the vibrations are very rapid; a mild taste, slow vibrations.
When a pleasant taste is detected, it is only because the filaments are
set into an agreeable motion. The vibrations in the tongue may become so
rapid that it will be painful, just as a shriek becomes piercing to the
ear, or an intense light dazzling to the eye; all proceed from the same
physical force acting on the brain.
COLOR.--Color, that seemingly unexplainable force, becomes a simple
thing when the principles of vibration are applied, and this has been
fully explained by the spectroscope and its operation.
When the boy once appreciates that this force, or this motion in nature
is just as simple as the great inventions which have grown out of this
manifestation, he will understand that a knowledge of these things will
enable him to utilize the energy in a proper way.
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