ANIMATED MACHINERY
IN MARKED contrast to the massive machinery and apparatus described
in the last chapter, and fully as wonderful, is a class of machinery
to which we might apply the term “animated.” By this we do not
mean manikins or toys, but certain higher types of machines which
seem to be possessed of powers that we should expect to find only
in living beings--machines that have a sense of touch, sight, and
hearing--machines that will reason out a mathematical problem; that
will talk; that have the equivalent of a memory. In this broad
classification we may include such widely different machines as the
motion-picture camera and projector, and that mysterious mechanism
which seems animated with strange powers of its own--- the gyroscope.
MATHEMATICAL MACHINES
Adding, subtracting, multiplying, dividing, and the working out of
complex mathematical problems by machine seems wonderful until we stop
to reflect that mathematics is the most precise and mechanical of
all sciences. In the simpler forms these machines are mere counting
mechanisms in which the counting is done very rapidly by the aid of
intermeshing gears. The adding machine is in no sense possessed of any
reasoning power, but blindly obeys the simplest of mechanical laws.
There are rows of wheels with numbers running from 0 to 9 printed on
their peripheries. One wheel represents “digits,” the next “tens,” the
next “hundreds,” etc. The wheels are interconnected by means of gearing
so that when the digits wheel makes a complete turn, the tens wheel
makes 1-10th of a turn, and when the tens wheel completes a rotation
the hundreds wheel makes 1-10th of a turn. Keys numbered from “0” to
“9” are provided, which respectively turn each wheel through angles
from 1-10th to 10-10ths of a rotation. Thus suppose the digit wheel has
already been turned through 9-10ths of a rotation and registers the
figure “9,” and the “8” key is depressed, the wheel will be given an
additional turn of 8-10ths of a rotation and will register the figure
“7,” but the tens wheel to the left will also move through 1-10th of
a rotation, so that the two wheels will register “17.” Such is the
underlying principle of the adding machine, but various refinements
are added. For instance, the numbers that are being added are recorded
in print, and the total sum of the numbers is not printed until the
operator desires to foot up the column.
More complicated, of course, are the mathematical machines which
work out involved equations, but they are all based on simple
mechanical operations. In the Weather Bureau at Washington there is a
tide-predicting machine, which has been called a “great brass brain.”
Its brass gears may be set to allow for all the varying factors of
apparent solar and lunar motions, and they will work out the tide
for any past or future data in a few moments, solving mechanically a
mathematical problem that, by hand, would take hours and hours of weary
figuring.
HEARING AND TALKING WITH A MECHANICAL “EAR”
It was in 1877 that Edison startled the world with a machine that could
actually talk. Others had been working on this problem for years, but
they had been trying to copy the human mouth and organs of speech.
Edison attacked the problem from a new angle. He was not aiming to
produce speech but to reproduce it. Let the human vocal organs modulate
the sound waves so that they would produce spoken words; he would
provide a machine with no mouth but only an ear and a very retentive
memory which would listen to these sound waves and make an impression
of them on its soft tinfoil or wax brain. Then, at any time by the
principle of “reversal,” the record could be made the transmitter
instead of the receiver of sound waves, and it would actuate the ear
so that it would repeat the sound vibrations it had formerly received.
Thus Edison made the ear of his machine serve the double office of
hearing and talking. When Edison’s phonograph was listening it had a
sharp needle attached to the ear-drum or diaphragm of the sound box,
which cut a hill and dale groove in the brain or cylinder record of the
machine; when reproducing, a blunt needle was used which faithfully
followed the hills and dales of the groove without cutting a path of
its own.
The next notable improvement in the phonograph was that of Emile
Berliner, who in 1887 invented the laterally vibrating needle which
cut a zigzag groove in the record instead of a hill-and-dale groove.
In other words, instead of having his recording needle move in and
out as in the Edison machine, it moved sidewise. He also invented
the flat-disk record, which has almost completely supplanted the
cylindrical record.
MACHINES THAT PICTURE MOTION
In a measure associated with the phonograph is the motion-picture
machine, a machine with an eye and a retentive memory, which records on
a sensitive retina a series of pictures that it is able to reproduce
at any time. The recording of still photographs is remarkable enough
in itself, but photography does not properly belong in a book on
machinery. The taking of motion pictures, however, and the projection
of these pictures upon the screen, involves the use of machinery, and
we must refer to these machines briefly, owing to their widespread use
at the present time.
Long years ago it was observed that when a picture is suddenly flashed
before the eye an image is impressed upon the retina, which persists
for a brief interval even after the picture itself has been withdrawn
from view. By preparing a series of pictures of a figure which show
it in progressive positions and flashing these pictures in rapid
succession before the eye, persistence of vision will bridge the gaps
between pictures and the figure will appear to move. This principle was
first used as early as 1834 in an ingenious toy known as “zoetrope,”
which consisted of a cardboard cylinder with a series of pictures drawn
on the inner surface. There were slots cut in the cylinder through
which these pictures on the opposite face of the cylinder could be
seen. As the cylinder was revolved the eye caught only momentary
glimpses of these pictures, one after the other, producing a sense of
motion. In 1870, Henry Heyl of Philadelphia prepared a progressive
series of photographs each separately posed before the camera.
From these he made glass positives and projected them on a screen
in rapid succession so that the picture appeared to move. In 1880,
Edward Muybridge set up a battery of cameras and took a succession of
instantaneous pictures of a galloping horse. The shutters were operated
by strings stretched across the course and as these were successively
snapped by the horse the pictures were progressively exposed. Glass
positives of these pictures were thrown on the screen by means of a
machine to which he gave the formidable name “zoöpraxiscope.”
INVENTION OF THE PHOTOGRAPHIC FILM
No one at that early date had thought of using anything but glass
plates, and they were difficult to handle, both in the camera and
in the projector. It was not until 1887 that the celluloid film was
invented by Rev. Hannibal Goodwin, and then it became possible for
Edison to invent a camera with a film that was intermittently moved
so as to take a series of pictures. From the negative thus obtained
a positive film was then made and placed in a machine known as a
“kinetoscope.” Looking through a peephole in this machine the pictures
were flashed before the eye in rapid succession. Finally, in 1893, C.
Francis Jenkins, of Washington, developed a projector similar to those
now in use by which the pictures could be thrown on a screen. Thus was
born the motion-picture industry which has taken such a strong hold on
the public.
It is now possible to project pictures in their natural color so as to
add to their realism, but one more step is needed to give a sense of
real life. The figures on the screen must talk as well as move. Efforts
to combine the phonograph with motion pictures have so far been only
partially successful. Perfect synchronism is very difficult to obtain,
but it is highly probable that obstacles which hitherto have been most
troublesome and seemingly insurmountable will, in time, be overcome.
Then the “silent drama” will no longer be silent and we shall have
“animated pictures” that will be really animated.
In addition to machines that talk we have machines that hear--machines
that will respond to sound waves. A diaphragm flexed by sound waves
closes an electric circuit and starts the operation of a machine. Some
toys have been made which operate on this principle. Experiments have
been made with a typewriter that will respond to a spoken message,
but so far they have not been attended with much success. Boats have
been built whose steering gear may be controlled by sound waves, but
as yet nothing of commercial importance has been developed in machines
controlled by sound.
MACHINES THAT SEE
Much more has been done with machines that see. There is a delicate
device known as a “sun valve,” which is used on beacon lights so that
as soon as it grows dark or very foggy the lamp is automatically
lighted, and when the day dawns or light breaks through the fog the
light is extinguished. The sun valve has two rods, one brightly
polished and the other a dead black. Light and its attendant radiant
heat waves are absorbed by the black rod, but are reflected from the
bright rod. As a consequence, the black rod grows hotter than the
polished rod and expands. The difference of expansion between the two
rods is utilized to operate a valve which controls the supply of gas to
the lamp. This valve is very sensitive and marvelously responsive to
variations of light.
There is a chemical element called selenium, which is peculiarly
sensitive to light. When light shines upon selenium its electrical
resistance is lowered, and hence it can be used as a light-operated
valve to control the flow of electric current.
A MACHINE THAT READS PRINT
One of the most marvelous machines of the present day is one which will
actually read ordinary printed type, uttering musical sounds that vary
for each letter, so that a blind man after learning this new musical
language can read any book. This machine, known as the optophone, is
the invention of Prof. E. Fournier d’Albe, and was developed to a
commercial success last year (1920). With it blind operators are able
to read at the rate of twenty-five words per minute.
The operation of this wonderful machine can best be understood by
reference to the accompanying diagrams, Figures 75 and 76.
[Illustration: Diagrammatic Arrangement of Optophone.
FIG. 75.--END VIEW OF THE OPTOPHONE]
[Illustration: FIG. 76.--SIDE VIEW OF THE OPTOPHONE]
There is an electric lamp in the machine before which there is a disk
that is revolved by a small motor. In this disk there are five circular
rows of slots and the light shining through these slots is cut up into
five pulsating beams of light. These beams are brought to a focus in a
vertical row upon the type page. From the paper they are reflected to a
selenium cell or bridge. The selenium bridge forms part of the circuit
of a telephone receiver and the diaphragm is thus made to vibrate at
the same frequency as the light beams do. By varying the number of
slots in each row in the disk the beams of light are given different
periods of pulsation or vibration and they produce a sound chord or
“scala” in the telephone receiver. The speed of the disk and the
disposition of the slots is so chosen that the notes produced are _G_
_C′_ _D′_ _E′_ _G′_ of the musical scale. Only white paper reflects the
light beams; the black surface of the printed type absorbs them. Thus,
as the row of beams is swept across a line of printed matter, the beams
will be extinguished in various orders of succession, or simultaneously
in accordance with the shape of the particular type-character they
encounter.
The middle three beams correspond to notes _C′_, _D′_ and _E′_, and
play upon the small letters, while _G′_ plays up the upper part of
capital letters, and _G_ upon the tails of such letters as _y_, _p_,
etc. If the scala passes over the letter “V,” for instance, first the
top note _G′_ is silenced, then _E′_, _D′_, _C′_, _D′_, _E′_ and _G′_
in succession. This arrangement constitutes what is known as the “white
sounding” optophone, because the full chord is sounded constantly,
except when the type matter is encountered.
To simplify the reading an improved type of optophone has been made,
which is known as the “black-reading” optophone, With this machine
there is no sound produced except when the type is encountered. The
letter “V” is then identified by the _sounding_, instead of the
_silencing_ of the notes _G′_, _E′_, _D′_, _C′_, _E′_ and _G′_. The
letter “A” produces the sounds _C′_, _D′_, _DE′_, _DG′_, _DE′_, _D′_
and _C′_. This result is obtained by using two selenium bridges, as
shown better in the side view, Figure 76. There is a concave reflecting
lens, which reflects half of the light upon the second cell, known as
the balancer selenium bridge. Electric current passing through the
balancer opposes the current passing through the main selenium bridge,
and hence there is silence in the telephone receiver when the scala
passes over plain white paper, but when type is encountered and certain
of the beams are not reflected against the main selenium bridge the
sounds are produced through the balancer bridge.
The success of the optophone leads one to hope that it may be but the
forerunner of a machine that will translate the whole world of light
and color into one of music, and permit the blind not only to read by
ear, but also to see their friends and their surroundings through the
sense of hearing. In fact efforts to make such an apparatus preceded
the invention of the optophone.
THE WILLFUL GYROSCOPE
As intimated above, we have included the gyroscope among the higher
type of machines, because it seems possessed of a stubborn will of its
own, and apparently defies the laws of gravity.
There is nothing mysterious about its mechanism. It is merely a wheel
with a heavy rim and with its axis mounted in gimbals, so that it may
turn freely in any direction. The wheel, when at rest, behaves no
differently from any other mechanism. But once the wheel is set to
spinning at a high velocity it seems to acquire marvelous powers and
obstinate notions of its own as to what it will do and what it won’t
do. You may lift it, or lower it, or move it sideways in any direction,
and it will not show the least sign of rebellion so long as the plane
of its rotation is not deflected, but attempt to twist its plane of
rotation and it will resist with the power of a giant. The resistance
that even a small gyroscope will develop is astounding. A wheel
weighing not more than 10 pounds may develop so much energy that a man
twenty times as heavy pushing with all his might cannot turn it over.
Not only does it resist the push, but it actually leans back against
the pusher. Then it has the peculiar habit of turning at right angles
to the direction in which it is pushed. Suppose, for instance, the axis
of the gyroscope is horizontal and it is resting freely on a pair of
supports, one at each end. Remove one of the supports and the gyroscope
does not fall. To do so it would have to swing around the other
point of support as a center; in other words, the plane of rotation
would have to be turned angularly and such a motion the gyroscope
resists. The unsupported end of the axis dips momentarily under the
pull of gravity, but immediately recovers and actually rises above the
horizontal, then it begins to revolve slowly in a horizontal circle
about the supported end of the axis--a motion which is technically
known as “precession”. The pull of gravity exerted in a downward
direction results in a horizontal motion at right angles thereto. It
seems as if the gyroscope was bidding defiance to laws that govern
other objects, but, of course, such is not the case. The gyroscope is
as submissively obedient to the laws of gravity as any other object
or machine, but the forces which act upon it are so complicated that
it is difficult for one to comprehend them without study. In fact, it
is almost impossible to explain the strange behavior of a gyroscope
without the use of mathematics that is too involved to be presented in
this book.
Of course, the underlying cause of gyroscopic action is inertia; _i.
e._, the tendency of a body to retain its state of rest or uniform
motion. A bullet is forced out of a gun by the sudden expansion of
gases behind it, but after it leaves the muzzle and the influence of
the gases, why does it keep on traveling? We may just as well reverse
the question and ask why it should ever stop. Having once acquired
a certain velocity it keeps that velocity because of its inertia or
mechanical helplessness, and it would keep on going forever were it not
for the resistance offered by the air and the pull of gravity, which
gradually draws it down to earth. It takes a deal of energy to divert
the bullet from its course. In a gyroscope we have a similar condition.
FORCES DEVELOPED IN A GYROSCOPE
We may conceive of a gyroscope as consisting of a stream of bullets all
tied to a center, so that they fly around in a circle. Any effort to
deflect the bullets out of their course will be resisted by each bullet
as it comes to the deflector. Here each bullet acts individually, but
in a gyroscope wheel the equivalent of the stream of bullets is a
solid rim, each particle of which is rigidly connected to every other
particle, and so the whole wheel immediately feels the deflecting force
and resists it. As long as the wheel is maintained in its own plane
of rotation, or moved into parallel planes, there is such a perfect
balance of all forces that no more resistance is offered to the motion
of the wheel as a whole than would be offered by any other object of
equal mass. But when the wheel’s plane of rotation is moved angularly,
a complicated series of forces is developed.
[Illustration: FIG. 77.--SOME OF THE FORCES DEVELOPED IN A GYROSCOPE
WHEN ITS PLANE OF ROTATION IS SUBJECTED TO ANGULAR MOTION]
Some idea of the nature of these forces and why they give rise to
precession may be understood by reference to the diagram, Figure 77.
Here we have a disk with a heavy rim turning on the axis X, X′. At
_A_, _B_, _C_ and _D_ are four particles whose flights we are going to
consider. Suppose the wheel to be at rest; then if _X, X′_ is tilted
in the direction of the arrows _x_ _x′_, the wheel will turn about
the line _Y Y′_; _D_ will move forward toward _D′_, and _B_ backward
toward _B′_, but _A_ and _C_ will remain where they are. Now, suppose,
the wheel to be revolving clockwise, or in the direction _A_, _B_,
_C_, _D_, then the particle _A_ will pursue a spiral course that will
bring it to _B′_, and _C_ will pursue a spiral course that will bring
it to _D′_. However, particle _D_ will have an irregular course, as
indicated by the dotted line, starting first to move forward and then
curving back toward _A_. The same will be true of _B_, except in the
reverse direction. The course of particles _D_ and _B_ is, therefore,
materially different from that of _A_ and _C_. Now, the particle
_D_ will resist being deflected from its course and will develop an
opposing force represented by the arrow _d_. A moment later this is
reversed as the particle bends back toward the axis _Y Y′_, and we may
represent the new force by the arrow _d′_. It may be proved that the
force _d′_ is more powerful than that of _d_. The particle _A_ in the
meantime exerts a force opposing its deflection, which is represented
by the arrow _a_. On the other half of the wheel there are similar but
opposite forces, _b_, _b′_ and _c_. The sum of these forces gives the
wheel a tendency to turn about the axis _Z Z′_. To avoid complicating
our diagram with too many arrows, we had better refer to a new diagram
(Figure 78) which shows only the resultant of the forces developed.
The application of the forces _x_ _x′_, which would have turned the
wheel on the axis _Y Y′_, had it been stationary, have resulted in the
development of forces _z_ _z′_ at right angles to _x_ _x′_, tending to
turn the wheel about the axis _Z Z′_. Now, if we go through the same
processes of reasoning as before, it will be evident that the forces
_z_ _z′_ will result in a third set of forces _y_ _y′_ at right angles
to _z_ _z′_ tending to turn the wheel about the axis _Y Y′_. The forces
_y_ _y′_ exactly balance the forces _x_ _x′_, and hence the wheel does
not turn about the axis _Y Y′_ in response to the original forces, but
starts instead to revolve slowly about the axis _Z Z_. Because the
forces _x_ _x′_ and _y_ _y′_ balance each other, there is no fourth
couple developed and hence no opposition to the forces _z_ _z′_.
[Illustration: FIG. 78.--DIAGRAM EXPLAINING PRECESSIONAL MOVEMENT OF A
GYROSCOPE]
The gyroscope was used as a toy ages ago. The top, which is one form
of gyroscope, was a favorite plaything of ancient Egypt. But although
known these many centuries, it is only in the past few years that any
real effort has been made to set the top to work. Because it persists
in maintaining its plane of rotation it has proved most useful on
submarine torpedoes to control the rudder and hold the torpedo on a
true course to its target.
THE GYROSCOPE AS A COMPASS
Another most important use for the gyroscope is found in the submarine
itself. The needle of a magnetic compass is kept pointing north by
action of the magnetic lines of force which surround this earth.
Whenever a large mass of iron is placed near the compass the magnetic
field is distorted and the compass needle is deflected from the
true north. On modern steel vessels the compass has to be carefully
corrected by using iron masses to counterbalance other disturbing
masses. However, in a submarine the whole shell of the vessel is of
steel and the magnetic lines of force flow along this shell. The
compass needle is virtually insulated from the terrestrial magnetism
by the surrounding steel hull. But, fortunately, the gyroscope may be
used as a compass and it is in no way affected by magnetism. Once the
gyroscope is set spinning with its axis pointing to the North Pole
of the heavens it will continue to point in that direction no matter
how devious a course the vessel may pursue. If pointed in some other
direction, the precessional forces set up by the rotation of the earth
will turn it due north. As the vessel rolls or pitches, disturbing
precessional movements are likely to be set up. These are overcome by
special mechanism, so that the gyroscopic compass may now be depended
upon as a perfectly reliable instrument.
PREVENTING SHIPS FROM ROLLING
One of the most remarkable recent developments of the gyroscope is
its use as a stabilizer in ships to keep them from rolling in a heavy
sea. A comparatively small wheel is mounted in the hold of the vessel
with perfect freedom to turn in any direction. If the wheel is clamped
so that it cannot precess, the vessel will roll and pitch, but the
instant the gyroscope is released it exerts its wonderful powers. The
ship rides smoothly and its groaning and creaking ceases, showing that
it is no longer subjected to severe strains. Of course, it rises and
falls with the waves, but it maintains an even keel as if sailing in
smooth water. The object of stabilizing a ship is not merely to cater
to the comfort of passengers who are subject to seasickness, but to
save wear and tear on the vessel and also to economize time and fuel.
An unstabilized ship riding a heavy sea pursues a very sinuous course;
in other words, it must travel farther than it would in smooth water.
The rudder must constantly be turned to keep the ship on its course,
and this acts as a drag on the progress of the ship, slowing it down
and wasting the power of the engine. As the ship wallows in the sea it
displaces much more water than it does when riding on an even keel and
here there is a further loss. It has been estimated that a 15,000-ton
vessel running at 18 knots may waste as much as 1,000 to 1,200
horsepower in a heavy sea. If stabilized with a gyroscope, practically
all this wasted horsepower would be saved at the expense of a very
small amount of power used in keeping the gyroscope spinning.
The first man to stabilize a ship with a gyroscope was Dr. Schlick,
who demonstrated the powers of this mysterious mechanism in 1906.
His stabilizer, however, was not sensitive enough to provide perfect
stabilizing. The ship had to roll some before the gyroscope exerted its
corrective forces. Recently, however, Mr. Elmer A. Sperry has improved
the stabilizer, making it so sensitive that there is practically no
rolling or pitching of the vessel.
Curiously enough, the gyroscope may be used not only to keep a ship
from rolling, but also to make it roll. Should a vessel run upon a
mud flat it may be rocked by braking or accelerating the precessional
motion of the gyroscope. In this way the ship may work itself out of
the mud bank. Ice breakers are equipped with gyroscopes, so that they
may be rolled to prevent them from being frozen into an ice pack and to
assist them in crushing their way through the ice.
THE MONO-RAIL CAR
In 1907 a sensation was created by the exhibition of a car which ran
on a single rail. The inventor of this monorail car was Mr. Louis
Brennan. The public was astonished at the ease with which this car
maintained its balance on the rail, leaning in as it rounded a curve
to keep its equilibrium. Passengers could move about at will without
the slightest danger of upsetting the car; in fact, if a heavy weight
was placed on one side of the car that side would rise rather than
fall. The car could run with equal ease upon a cable of a crooked pipe
line. The gyroscope that maintained the balance of the car consisted
of a couple of small wheels which revolved in a vacuum chamber at the
rate of 7,000 revolutions per minute. Once started, little power was
required to keep them going. Interesting as this car was, it did not
offer sufficient advantages over the present-day double rail cars and
locomotives to justify its development on a commercial scale. Although
witnesses of the exhibition marveled at the strange spectacle of this
mechanical tight-rope walker, they did not realize that they themselves
had had gyroscopic cars in their midst for years. The gyroscopic
action of the wheels of a motorcycle is very marked. It is this action
which is mainly responsible for holding the machine upright. The same
is true of a bicycle, although the gyroscopic effect is not quite so
marked, because of the lower velocity of the wheels. However, we all
know that any tendency for the machine to fall to one side or the other
may be corrected by a slight turn of the front wheel in that direction
which at once has the effect of bringing the bicycle back to vertical
position.
THE AUTOMATIC AEROPLANE PILOT
Still another recent development of the gyroscope is its use as an
“automatic pilot” on aeroplanes. Two sensitive gyroscopes are used
to stabilize the aeroplane. If a gust of wind tends to tilt the
machine, the gyroscopes immediately sense the deviation and by closing
electrical circuits operate the ailerons to bring the machine back to a
horizontal plane.
An aviator possesses a certain sense of balance which is highly
developed by experience and long practice, but at its best it does not
begin to compare with sense of balance possessed by the gyroscope. Not
only will it keep the machine from tipping laterally, but it will also
hold it on a level keel and can be used to steer the aeroplane in any
desired direction, so that the human pilot may surrender the helm to
the faithful mechanical pilot with perfect confidence in the ability of
this animated machine to hold the aeroplane on a true course despite
the vagaries of the wind. While this is theoretically possible, in
practice certain difficulties are encountered which up to the present
have prevented gyroscopic control of aeroplanes from being entirely
successful.