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.

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.

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'.

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.

---