A—Oscillator B—Opposite side of earth C—Waves in nodal and ventral intervals.
A—Oscillator B—Opposite side of earth C—Waves in nodal and ventral intervals.
A—Oscillator B—Opposite side of earth C—Waves in nodal and ventral intervals.
As Tesla put it, "The outgoing and returning currents clash and form nodes and loops similar to those observable on a vibrating cord." Tesla figured from these experiments that the waves varied from 25 to 70 kilometres from node to node, that they could be sent to any part of the globe, and that they could be sent in varying lengths up to the extreme diameter of the earth.
In order to prove his discovery Tesla sent an impulse into the earth, and received it back, on his delicate instrument, in a few seconds. "It is like an echo," he explained. "When you shout and in a few seconds hear your voice coming back, you do not think it is another voice but know immediately that it is simply your own vocal vibrations reflected by the house, mountainside, or what not. It isjust the same with an electrical vibration. The stationary terrestrial wave goes through the earth, reaches the other side and, finding no outlet, is reflected without any loss of power. Indeed, in some cases it is returned with greater power than at first."
"Then in your system the wireless electrical current passes through the earth, and not through the air," interrupted the scientist.
"No," he answered, "it passes through both. It is difficult to understand the big things about electricity, but just think of the earth as a great ball filled with electricity, as I said before. Think of the tower of the oscillator as a tube, and of the great mushroom-shaped top of the plant as another ball. Now from our great alternating current dynamo we first fill the ball at the top of the oscillator with electricity, and then we make a motion that corresponds to squeezing it. What happens? Just what happens when you have two rubber balls connected with a tube. You squeeze one of them, and push the air, or water, into the other ball. In that way we push the electricity into the earth, but it comes back to us on the stationary waves, from the opposite side, and when it does we are ready to give it another mighty push with another tremendous squeeze from our dynamo. When this is going on the top of the oscillator is gathering electricity from the air all the time and sending it out to be used wherever there is a receiver properly tuned to receive these rates of vibration."
"But," again asked our friend, "isn't there a great deal of valuable electrical power wasted in that way?"
"No, there is very little waste," answered the electrician, "for this reason: If, for instance, our oscillator can generate a hundred thousand or a million, or any other number of volts, and we only wish to use it for some small purpose on the other side of the earth, the receiver at the antipodes takes as much power as is needed, and the rest remains unused and our oscillator can be run at reduced capacity."
Thus, according to Tesla's plan, the electrical energy will be sent into the earth and air by the high potential magnifying transmitter or oscillator, the stationary electrical waves carry it through the earth and the receiving instrument on the other side of the world collects the energy to put it to a thousand and one purposes of mankind. And do not forget that the oscillator and the receiving instrument are so tuned to each other that there is no danger, according to Tesla's scheme, of different oscillators and receivers getting mixed up.
Before Tesla had discovered the stationary electrical waves he had gone deep into the mystery of the "individualization" of electrical impulses, and as a result advanced plans for sending a number of messages over one wire without their interfering with each other. This study was continued with even greater energy, after he had taken the firststeps toward the realization of his world telegraphy and world telephony without wires. In wireless telegraphy as we know its practice to-day, one of the serious drawbacks is the interference of other operators, both amateur and professional, with important messages. Tesla holds that the simple tuning of instruments to one another as is done nowadays would not be sufficient, when there were millions of currents passing through and around the earth. For instance, he says that an instrument tuned to a single rate of vibrations would be very apt to come into contact with another instrument sending at the same rate. Of course the confusion so familiar in modern radio-telegraphy would result. Moreover, it makes it difficult to send messages that cannot be intercepted and read by every wireless operator in hearing. "This can be avoided," continues the inventor, "by combining different tones or rates of vibration. In actual practice it is found that by combining only two tones, a degree of privacy sufficient for most purposes is attained. When three vibrations are combined it is extremely difficult even for a skilled expert to read or disturb signals not intended for him. It is vain to undertake to 'cut in on' a series of wireless impulses made up of four different rates of vibration. The probability of getting the secret of the combination is as slight as of your solving the number combination on the door of a safe. From experiments I have concluded thatthis individualization will allow the transmission of several million different messages. It is interesting when you think that one world telegraphy plant would have a greater capacity than all the ocean cables combined."
In regard to the amount of power to be transmitted, Tesla points out that an impulse of low voltage, or low horsepower, will carry to the other side of the earth without any loss of power, just as easily as a high voltage current. "A wire," says Tesla, "offers certain resistance to an electrical current causing some loss, but not so when it is sent through the natural media. The earth is a conducting body of such enormous dimensions that there is virtually no loss, so that distance means nothing. To the average intelligence this will appear incomprehensible. We are continuously confronted with limitations, and those truths which are contradicted by our senses are the hardest to grasp. For example, one of the most difficult tasks was to satisfy the human mind that the earth rotated round the sun; for to the eye it seemed just the opposite."
Tesla further pointed out that five-hundred miles is about the farthest that high power can be transmitted by wires with complete success, but that without wires, by his system, power can be transmitted, as we have seen, to any part of the globe or the atmosphere about it.
The plan for a world-wide system of wirelesstelegraphs and telephones differs considerably from the original idea laid down by scientists for radio or Hertzian wireless telegraphy. Originally Guglielmo Marconi, who first successfully telegraphed without wires, and whose system is well known all over the world, planned to send his electrical impulses through the ether, in the form of Hertzian rays, but later the method was amended. The theory advanced was that since everything is afloat in the colourless, intangible something called ether (not the drug used as an anæsthetic), and that since waves of light, heat, and electricity travel through ether, it would be possible to send electrical impulses through the ether in the earth and air, just as well as through the ether in a copper wire. In his early experiments Marconi used the light rays or waves named after their discoverer, Hertz, but these were found to be very limited, so electrical vibrations of a higher intensity were substituted, as we shall see in a later chapter.
"From the very first," declared Tesla, "my system has been based on a different principle, as you can see from what I have told you. For instance, my invention takes no consideration of light rays in any visible or invisible form (and Hertzian rays are invisible light), which can only travel in a straight line. Hence, you can see that they could not be used except as far as could be seen. In other words, they only could be used as far as the horizon, for just as soon as the curve of the earth's surface took the receiving instrumentbelow the level of the Hertzian waves they became ineffective. You see the difference is that my system is based on the stationary earth waves, along which the electrical currents can pass to any distance irrespective of horizon, or matter."
A simple explanation will serve to show the principle of Tesla's theory of wireless telegraphy and telephony. We can easily think of a reservoir with two openings in the cover filled with some fluid. In each of these openings is a piston and above each piston is a tuning fork. The two tuning forks must be of exactly the same tone or the experiment will not work. We strike one of the pistons with the tuning fork, and continue to strike it until the fork sets up vibrations. The vibrations pass through the air, and also communicate vibrations to the piston, which in turn passes the vibrations on to the fluid in the reservoir. These vibrations naturally continue through the reservoir, as waves, just the same as when we throw a pebble into a calm pond and watch the waves radiate out in every direction. The water does not advance, but merely moves up and down. The waves, however, advance. So with the waves set up by the tuning fork, and they set up an oscillation of the piston at the other side, agitating the tuning fork in unison with the sound vibrations coming through the air.
It is just the same, declares Tesla, with two of his oscillators set up on the earth's surface and tappingthe great sea of electricity, which he says is in the earth. The oscillators correspond to the tuning forks, the reservoir to the earth, and the fluid in the reservoir to the electrical currents with which he says the interior of the earth is alive. Exactly attuned, Tesla says, the vibrations set up by the sender will be communicated to the receiver through the earth and through the air.
"Now, with the development of the world system," continued Tesla, "we shall be able to telephone without wires just as well as telegraph, and to any part of the world just as easily as we now talk to a friend in an adjoining house over the modern wire circuits."
Before going with Doctor Tesla to his great plant out on Long Island to see how he is carrying on these tremendous theories of his, the boy asked him a few more questions about them, for it is a big and intricate question.
"What application will you first make of the wireless transmission of power?"
"My first concern," replied the magician of electricity, "will be to make air and water navigation safe. We have plenty of demonstrations of the value of the wireless telegraph in saving human lives when ships are in danger, in theRepublicandTitanicdisasters. But also we know that the wireless can be greatly improved upon. With a perfect system of communication, both by wireless telegraph andtelephone, consider what it would mean to the navigators of air and ocean craft.
"By the art of telautomatics, which is a part of the broad scheme for the wireless transmission of power, many of the worst dangers of air and water navigation will be avoided, which is right in line with the modern tendency of preventing trouble rather than waiting for it to happen before remedying it." He then went on to enumerate the various telautomatic devices that will be carried by ocean liners and airships of the future, as mentioned in the early part of this chapter.
"Just for instance, how could telautomatics have saved theTitanic?" the inventor was asked.
"You understand, of course," answered Tesla, "that the devices I propose would be of almost inconceivable sensitiveness. They would be the centre of electrical waves, and, as soon as the iceberg got into the path of these waves from the wireless transmission plant to the ship, it would cause the electricity to register an impression of danger ahead. Of course mariners would become so expert in the reading of these danger signals that they could tell the meaning of each one, and alter their course or reverse their engines according to the needs of the case."
"How much have you accomplished in telautomatics at this time?"
"I have made a little submarine boat that willanswer to every necessary impulse. The boat contained its own motive power in a storage battery and gear for propulsion, steering sidewise, or upward or downward, and all other accessories necessary for its operation. All of these were worked from a distance by wireless impulses, sent by an oscillator to the circuit in the boat through which magnets and other devices operated the interior mechanism.
"This proved to me the possibility of a high development of telautomatics. When my system is complete, a crewless ship may be sent from any port in the world to any other port propelled by wireless energy from a power plant anywhere on the face of the earth, and controlled absolutely by telautomatics."
Tesla's plan for aerial navigation is even more startling than that for crewless ocean liners. He thinks that the airships of the future will be propelled by wireless power and that they will have, neither planes nor other supporting surfaces, such as we are so familiar with nowadays. Neither will they be supported by gas bags like balloons and dirigibles. The inventor thinks they will be compact and just as airworthy as ocean liners are seaworthy. They will be tightly enclosed, so that the terrific rush of air through the high altitudes will not strangle the passengers and crew. He sees no reason why the airships of the future should not travel at a rate of several hundred miles an hour, so that you could leave SanFrancisco in the morning and be in New York in time for a six o'clock dinner, and the theatre, or cross the Atlantic in a night.
"How will these airships be propelled?" the boy asked.
"By engines driven with power supplied by our great oscillator wherever we care to erect it. These engines will work with such incredible force that they will make of the air above them a veritable rope to sustain them at any desired altitude, while they will make of the air in front of them a rope to pull them forward at a high rate of speed." Tesla continues to say that these ships can be made just as large as it is practicable to make their landing stages, or small enough for one or two passengers.
In the waterfalls of the United States alone, he pointed out, there are twenty-five hundred million horsepower of electrical energy. Niagara Falls could supply more than one fifth of all the power now used in this country, he says. Moreover, none of the great sites, such as those in the far Northwest, are developed to their highest state, because of the difficulty in transmitting the power over long distances to where it is used.
"It must be borne in mind," said Tesla, "that electrical energy obtained by harnessing a waterfall is probably fifty times more effective than fuel energy. Since this is the most perfect way of rendering the sun's energy available the direction of the futurematerial development of man is clearly indicated. He will live on 'white coal.'"
"Doctor Tesla, can you tell us, please, just how far you have developed this invention for the wireless transmission of power?"
"Well," answered the electrical inventor, "the best way to tell you is to show you what has been done so far." In order to see Tesla's great plant we must follow the scientist and his boy friend out to Bay Shore, L. I., where, overlooking Long Island Sound, we see a great mushroom-shaped steel network tower surmounting a low building—the first of Tesla's many proposed high potential magnifying transmitters.
"So far," said Tesla of his power plant where the first attempts at wireless transmission are being made, "only about three million horsepower has been harnessed by my system of alternating current transmission. This is little, but it corresponds nevertheless to adding to the world's population sixty million indefatigable laborers, working virtually without food or pay."
As the boy approached the power plant he was impressed by the great size of the tower and its circular top, as shown in the photograph. It is this circular top, with its conductive apparatus, that gathers the electricity from the air and from the dynamo, and sends it forth in great waves both through the air and through the earth.The tower is 185 feet high, from the ground to the top, and from the ground to the edge of the cupola it is 153 feet. The diameter of the cupola floor is 65 feet. The cupola can be reached by both a staircase and an elevator, but it would hardly be healthy for any one to be within the network of electrical conductors when the plant was working. Inside the building are the high power alternating dynamos and underneath it extends the ground wire from the cupola, through which the electricity is pumped into the ground in great spurts at the rate of more than a hundred thousand spurts a second. At this plant Tesla plans to gather and concentrate millions of horsepower of electrical energy and then, in the ways we have seen, send it out to be used in a thousand different ways.
"This is merely an experiment," declared Tesla. "We can telegraph and carry on other such operations as require only a small amount of power from here, but it is nothing compared to the great power plants we will erect in the future."
"Is it necessary," asked the boy, "to have your power plant erected near the waterfall, or other means of producing the electricity?"
"No, it is not. This plant, for instance, can be made a great receiving station for electric power from all the great hydro-electric sites, and from it we hope to be able to send out electrical waves that will run our ships, airships, trains and street cars, carryour voices, light our houses, and turn the wheels of our factories. It is better, however, to have the plants located close to the seats of power, and to have a greater number of plants."
"How much horsepower did you say this plant would send out?"
"Only a mere trifle of three million horsepower, but of course this is only an experiment. To be done properly the thing must be done on a large scale, and the time will come—not necessarily remote—when we will be carrying on the whole programe embraced by the wireless transmission of power. The cost of wireless power I estimate would be about one sixteenth of that of the present system."
"When you are sending such tremendous voltages won't it be very dangerous to be anywhere in the vicinity of a plant, much less anywhere that the electricity might be brought from the earth?"
"No, for the power is so well harnessed that we can send it just where we want it and nowhere else. Of course, on the other hand, if we wanted to make trouble with this well-harnessed lightning we could make a terrible disturbance in the earth and on the surface of the earth."
"What about lightning?"
"That is one of the things we had to guard against right from the very first, and I can tell you that lightning will not bother us a bit, although I cannot give you the details of our method of avoiding it.
"When we are using the plant at night, however, there will be a display far more beautiful than lightning, all about the cupola in the form of a great halo of electric light visible for miles around."
Before we leave this fascinating subject of the wireless transmission of power let us ask Doctor Tesla about the effect of his invention on war.
"The wireless transmission of power will first be a big factor in promoting world peace, as I said before, because through the great improvement in communication it will lead to a better understanding between nations and break down many of the old prejudices that have lived for so many thousands of years. It will facilitate travel and commerce so that a citizen of the United States will find it as simple and cheap to travel abroad as he now finds it to travel in the neighbouring state. His commercial interests also will spread to foreign countries, and the nations will be so linked with one another socially and commercially that war will be out of the question.
"However, in case war should break out between the nations it will be a conflict of such gigantic proportions, and carried on with such tremendous death-dealing machines, that it will surpass our wildest dreams.
"For one thing, the new art of controlling electrically the movements and operations of individualized automata at a distance without wires will soonenable any country to render its coast impregnable against all naval attacks.
"I have invented a number of improvements of this plan, making it possible to direct a telautomaton torpedo, submersible at will, from a distance much greater than the range of the largest gun, with unerring precision, upon the object to be destroyed. What is still more surprising, the operator will not need to see the infernal engine or even know its location, and the enemy will be unable to interfere, in the slightest, with its movements by any electrical means. One of these devil-telautomata will soon be constructed, and I shall bring it to the attention of governments. The development of this art must unavoidably arrest the construction of expensive battleships as well as land fortifications, and revolutionize the means and methods of warfare. The distance at which it can strike, and the destructive power of such a quasi-intelligent machine being for all practical purposes unlimited, the gun, the armour of the battleship, and the wall of the fortress, lose their import and significance. One can prophesy with a Daniel's confidence that skilled electricians will settle the battles of the near future, if battles we must have.
"The future of wireless power development," explained the inventor, "may render it folly for any nation to have afloat a vessel of war. The secret of another nation's scheme of selectivity or combinationof vibrations might be disclosed to the enemy, when the guns of their own vessels might be turned against sister ships and a whole fleet destroyed by shells from their own guns, or their magazines might be exploded by the enemy at will. However, should there be battleships in the wireless future, they will be crewless. They will be manœuvred, their guns will be loaded, aimed, and fired, and their torpedoes discharged with unerring accuracy, by the director of naval warfare seated before a telautomatic switch-board on land.
"The time will come, as a result of my discovery," says Tesla, "when one nation may destroy another in time of war through this wireless force: great tongues of electric flame made to burst from the earth of the enemy's country might destroy not only the people and the cities, but the land itself. I realize that this is indeed a dangerous thing to advocate. At first thought it might mean the annihilation of the nations of the world by evilly disposed individuals. The public might at first look upon the perfection of such an invention as a calamity. We say that all inventions assist the criminal in his work. To-day the safe burglar despises the use of dynamite, turning to electrical contrivances to cut the lock from a safe. It is fortunate for the world, therefore, that 90 per cent. of its people are good, and that only 10 per cent. are evilly disposed: otherwise all invention might be turned more greatly to evil than to good."
CHAPTER VTHE MOTION-PICTURE MACHINE
MACHINES THAT MAKE SIXTEEN TINY PICTURES PER SECOND AND SHOW THEM AT THE SAME RATE MAGNIFIED SEVERAL THOUSAND TIMES—MOTION PICTURES IN SCHOOL—OUR BOY FRIEND SEES THE WHOLE PROCESS OF MAKING A MOTION-PICTURE PLAY.
"IHAVE just been to the moving-picture show," said the young man whose inquiring turn of mind has brought him into touch with so many recent inventions. His friend in the laboratory had just finished a very successful chemical experiment and seemed glad to see the boy.
"Did the pictures move very much?" he asked with a smile.
"Of course they did. They moved all the time."
"No, they only seemed to move, for as a matter of fact there are no such things as 'moving pictures.' We call them 'motion pictures' now, for that comes nearer to expressing the idea.
"Cinematography, which is the technical name for the whole art of motion pictures, is based on one of nature's defects, whereas most inventions are basedon some of nature's perfect processes. The defect is called by the scientists the persistence of vision, which means that after you look at an object, and it is quickly taken from before your eyes, the image remains there for the fraction of a second.
ELECTRICITY ENOUGH TO KILL AN ARMY PERFECTLY HARNESSEDThe Oscillator shown on the left sending an alternating current from the earth into a large reservoir and back at the rate of 100,000 oscillations per second causes the tremendous electrical explosions as the reservoir is filled each time. The flames in this experiment were 22 feet long.
ELECTRICITY ENOUGH TO KILL AN ARMY PERFECTLY HARNESSEDThe Oscillator shown on the left sending an alternating current from the earth into a large reservoir and back at the rate of 100,000 oscillations per second causes the tremendous electrical explosions as the reservoir is filled each time. The flames in this experiment were 22 feet long.
ELECTRICITY ENOUGH TO KILL AN ARMY PERFECTLY HARNESSED
The Oscillator shown on the left sending an alternating current from the earth into a large reservoir and back at the rate of 100,000 oscillations per second causes the tremendous electrical explosions as the reservoir is filled each time. The flames in this experiment were 22 feet long.
Courtesy of Thomas A. Edison Inc.A BATTLE SCENE IN THE STUDIOIn this picture the stage director can be seen shouting directions to both actors and photographer at once.
Courtesy of Thomas A. Edison Inc.A BATTLE SCENE IN THE STUDIOIn this picture the stage director can be seen shouting directions to both actors and photographer at once.
Courtesy of Thomas A. Edison Inc.
A BATTLE SCENE IN THE STUDIO
In this picture the stage director can be seen shouting directions to both actors and photographer at once.
"With this in mind you will see how the cinematograph is simply still photography worked out so as to show a series of snapshots at such speed that the eye cannot notice the change from one picture to another, but will see only the changing positions of the figures. Each picture shows the figures in a little different position, in the same order that they move, so that the whole series thrown on the screen at high speed shows the figures moving just as they do in real life."
"But where does visual persistence come in?" asked the youth.
"It would be plain if you could see the pictures thrown on the screen twenty times as slowly as they are, for each snapshot of each stage of motion must be displayed separately. It must remain perfectly still for an instant and then must be moved away while the shutter of the projecting machine is closed. When the shutter is opened again the next picture is thrown on the screen. Now, through the persistence of vision, the image of the first picture remains in your brain, photographed on the retina of your eye, while the shutter is closed, and you arenot conscious that there is nothing on the white screen before your eyes.
"The scientific explanation of this is simple enough: After an image has been recorded by your eye it will remain in the brain for an instant even after the object has been removed. Then it fades slowly away and gives place to the next image sent along the optic nerve from the eye. Thus the eye acts as a sort of dissolving lantern for the motion-picture man, and lets one image fade into another without showing any perceptible change in pictures. Thus the 'moving picture' is only a scientifically worked outillusionof motion."
The scientist went on to say that with marvellously constructed machines this scientific fact has been turned to such account that boys and girls in some of the schools now study geography partly from motion pictures, and some of the most wonderful sights of nature are seen every day by millions of people as they sit comfortably in their seats in the motion-picture theatre. A few years ago, before the invention of cinematography, the magic lantern was largely used, as many boys will remember; but it could only show scenes in which there was no movement—or in other words, scenes that were confined to still-life photography. Nowadays every boy is familiar with motion pictures depicting great historical occurrences, parades, inaugurations, coronations, volcanoes in eruption, earthquakes, buildingsburning and crumbling, railroad wrecks, shipwrecks, scenes in every country in the world and plays of every imaginable kind.
The motion-picture photographer takes pictures in the frozen North, and in the densest tropical jungles. He goes close to the craters of volcanoes in eruption to make a film of the terrifying flow of molten lava, and he sails the seas in the worst storms, that boys and girls who have never seen the ocean may understand its mighty upheavals. One motion-picture outfit was taken to the Arctic regions off the coast of Alaska where the volcanic activity in Behring Sea frequently causes new islands to spring from the ocean, or old ones to sink out of sight, in an effort to record on the motion-picture film the birth of a new island or the death of an old one.
"Ever connected with scientific research, cinematography," said the boy's friend, "is now one of the important branches of recording the phenomena of nature through which great scientific discoveries are made. Of late years we have heard much about germs, and the science of germs called bacteriology. A great deal has been learned about this most important factor in the preservation of our health, through the study of disease germs, by watching their activities through the medium of the cinematograph. The little parasites are photographed under a very high power microscope and the film is cast upon a screen in the usual way.
"Also exploring parties and parties that go into remote places to search for additions to our store of scientific knowledge invariably carry motion-picture outfits. One of the most notable examples of this was the expedition of Lieut. Robert F. Scott in his search for the South Pole. Lieutenant Scott carried many hundreds of feet of standard film, a good camera, and a portable developing outfit, with which he made pictures of the Antarctic Continent, in order to show the world the things that he and his men risked their lives to see.
"As I said before, the cinematograph is rapidly growing as an educational force, and Thomas A. Edison, the pioneer inventor and the leader in the development of the cinematograph, declares that it will in a short time completely do away with books in the study of geography. It is already in use in several special school and college courses, and with the improvements in the non-inflammable film, which will be explained later, it can be taken up far more extensively."
The man went on to say that in this connection Mr. Edison, who had been watching the schoolwork of his own twelve-year-old son Theodore, recently said in the magazineThe World To-day(nowHearst's Magazine):
"I have one of the best moving-picture photographers in the world in Africa. I told him to land at Cape Town, and to take everything in sight betweenthere and the mouth of the Nile. His pictures will show children what Kaffirs are and how they live. He will show them at work, at play, and in their homes. They will be life-size Kaffirs that will run and skip or work right before the children's eyes. But the Kaffirs will be but the smallest part of what the African pictures will show. The biggest beasts of the jungle—the elephants, lions, rhinos, and giraffes—will be shown, not in cages, but in their native haunts. The city of Cape Town will be shown with its characteristic streets and its shipping. The broad veldts over which Kruger's armies marched will be shown just as they are, with here and there a burgher's cottage. Every step in the process of mining gold and diamonds will be put upon the film. The Nile will be shown, not as a small black line upon a map, but as a body of beautiful blue water, alternately plunging over cataracts and creeping through meadows to the sea. Then will come the Pyramids, with natives and tourists climbing them, and, lastly, the great cities of Alexandria and Cairo. Would any child stay at home if he knew such a treat as this was in store for him at school? Would he ever be likely to forget what he had learned about Africa?"
"Of course," continued the man in the laboratory, "this is but an example of the use of motion pictures in schools. Many of you boys have probably seen them in special lectures on other subjects, for they can be used to show how people live and work in every part of the world and how the various commercial products that so largely govern our lives are made."
But the motion-picture man, he explained, is not at all dependent upon what really happens for his films, because if he cannot train the eye of his camera on some occurrence that he desires to transfer to a film, he reproduces it in a studio, spending thousands and thousands of dollars, if necessary for actors, scenery and stage fittings. Nothing is too difficult for the motion-picture man, and he has never proposed a feat so daring but what he could find plenty of actors willing to take the necessary parts. Battles, scenes from history, sessions of Congress, railroad wrecks, earthquakes and hundreds of other spectacles have been planned, staged and acted out by the makers of cinematograph films, while, of course, all the plays that we see on the screen are planned and carefully rehearsed before they are photographed.
This all means that cinematography has become a gigantic industry, giving employment to hundreds of actors, photographers, and the army of men and women engaged in making and showing the films, to say nothing of the thousands of picture theatres that have sprung up in every city and town in the country.
While the boy's friend was telling him these things about the adventurous life of the motion-picture man, the listener sat spellbound.
"I'd love to see some motion pictures made," he said. "The machines must be wonderful."
"Well," answered the scientist, "we can do that, and if you'd like we can go up to one of the motion-picturestudios some day soon and see the whole process from beginning to end."
He was as good as his word, and several days later they were initiated into all the tricks of cinematography at one of the biggest laboratories in the country. We will follow them there and see what they found out about the machines by which motion pictures are made and shown.
With the fact clear in mind that cinematography is simply a series of snapshots of figures in motion, taken at high speed and thrown on a screen at a similar rate so that the human eye is tricked into sending to the brain an impression of moving figures rather than a series of still photographs, the various machines necessary in cinematography will not be difficult to understand.
Before there can be a cinematograph play there must be a negative film upon which the pictures are taken, a camera to take the pictures, an apparatus for developing them, a positive film which corresponds to the printing paper in still photography, upon which the pictures are printed from the negative film, a printing machine to print the positives from the negatives, and lastly a projecting machine to throw the picture upon the screen in the schoolroom, college lecture room, or theatre.
Every boy who is an amateur photographer is familiar with the photographic film. Up to the time the method for making practical cinematographfilms was discovered in this country, scientists vainly tried to portray motion by the use of photographic plates, but had little success. In a very short time after Eastman had announced the discovery of a celluloid substance that was transparent, strong and flexible, light, and compressible into a small space, Edison announced a machine for showing motion pictures.
The film base, or, in other words, the material which takes the place of the glass used in glass plates, was discovered by George Eastman in 1889, after years of painstaking experiment with dangerous chemicals. The base is a kind of guncotton called by chemists pyroxylin, which is mixed in wood alcohol. The guncotton is made by treating flax or cotton waste with sulphuric and nitric acids. After the guncotton and the wood alcohol have been thoroughly stirred up, the mixture looks like a thick syrup, but it is about as dangerous a syrup as ever was brewed, for its ingredients are those of the most powerful explosives. Its technical name is cellulose-nitrate. It is poured out on a polished surface, dried, rolled, trimmed, and after being coated with the sensitive material that makes it valuable for photography, is ready for delivery to the motion-picture maker in lengths up to 400 feet.
THE MEN WHO GAVE THE WORLD MOTION PICTURES
Eadweard Muybridge, called the "Father of Motion Pictures."
Eadweard Muybridge, called the "Father of Motion Pictures."
Eadweard Muybridge, called the "Father of Motion Pictures."
Thomas A. Edison, inventor of the motion-picture machine.
Thomas A. Edison, inventor of the motion-picture machine.
Thomas A. Edison, inventor of the motion-picture machine.
THE MOTION-PICTURE PROJECTORThis is the standard Edison projector from two points of view, showing its complicated mechanism as clearly as possible.
THE MOTION-PICTURE PROJECTORThis is the standard Edison projector from two points of view, showing its complicated mechanism as clearly as possible.
THE MOTION-PICTURE PROJECTOR
This is the standard Edison projector from two points of view, showing its complicated mechanism as clearly as possible.
One of the interesting points to remember about these films is that although they are made in lengths up to 400 feet they are all one and three eighths ofan inch wide, and the three eighths of an inch is given over to a margin at each side of the picture. That leaves a width for each picture on the film of just one inch. The height of each picture is three quarters of an inch. Fancy a photograph one inch by three quarters of an inch! No matter how clear it is you could not see with the naked eye all its details, and so it is in the cinematograph picture. It is so clear and sharp that when put under a good magnifying glass details that cannot be seen by the human eye are noticed. Now fancy multiplying the area of each little picture 2,700 times, and think of the chance for magnifying imperfections! And yet that is the amount that each picture is magnified in throwing it on a screen of the average size.
The films are coated with the sensitive emulsion in two degrees. The negative films must be as sensitive as possible to light, as they are intended to receive the shortest possible exposure, while the positive films, or the ones which correspond to the print paper in still photography, are made less sensitive to light, inasmuch as they are exposed for a longer time in the printing machine.
Fireproof films are probably one of the most important developments in the whole great motion-picture industry, for through these, schools, colleges, churches, lecture halls, and other public places not fitted with the fireproof box in which the motion-pictureoperator works, can have the advantage of cinematography.
It was a difficult matter to find a non-inflammable film, for science has not yet discovered a base that can be made without cellulose, but the base we know to-day was treated so as to be non-explosive and practically non-inflammable. This film base is called cellulose-acetate, and when it is exposed to an excessive heat, as, for instance, the beam of the motion-picture lamp when the film is not moving, or when it touches a flame, it melts but does not blaze up. In the melting it gives off a heavy smoke, but there is no serious danger from this, as there is from the spurting flames from an exploding cellulose-nitrate base.
The films are packed in metal airtight and lightproof boxes and sent to the motion-picture firms, where they begin a complicated and an interesting career. The first stage is the perforating machine, through which all films, whether negative or positive, must go. The holes are made along the two edges of the celluloid strips, just as shown in the picture opposite page176. There are sixty-four holes to the foot, on each side of the film, and each hole is oblong-shaped, as can be seen, with a width of about one eighth of an inch and a depth of about one sixteenth of an inch. This is known as the Edison Standard Gauge, and it is observed by practically all the motion-picture firms in the world.
The perforations along the edges of the films furnish the means for drawing them through the camera, printing machine, and projector; and as the correct movement of the films is one of the important factors in making good pictures, they must be absolutely mathematically exact. A fault in perforation of even as much as one thousandth part of an inch is apt to cause the film to buckle in the camera or projector and ruin the whole thing.
There are several different perforating machines in use now, and all of them are claimed by their makers to be perfect. It will not be necessary for us to take one of these machines to pieces further than to see that the holes along the edges of the films are punched by hardened steel punches. The films unwind from one bobbin, pass through the perforating device, and wind upon another bobbin. Of course the work must be done in absolute darkness, except for a small ruby lamp, as the films are so sensitive to light that any rays other than faint red would spoil them.
After perforation the negatives and positives are ready for use. The negative goes to the photographer in its light-tight metal box to be run off in making a film of a historical scene, a comedy, some wonderful phenomenon of science, or any one of a million different subjects. Just for the sake of seeing everything in its proper order we will assume that the negative is about to be used in portraying a comedy about the troubles of a book agent, andthat it is all done in the studio where the scientist and his boy friend watched this very film made.
Now for a look into a motion-picture camera—something few people get, because the competition among the various cinematographers is keen, and those who hold patents on cameras fear infringement.
The camera, which is enclosed in a strong mahogany box, stands upon a tripod. It is about eighteen inches long, eighteen inches high, and four inches wide. (This size varies with the make, and kind of work required.) The left side opens on a hinge, while on the right side are the ground glass finder, the distance gauge, and a dial to register the number of feet of film used. In the rear of the camera is a small hole which connects with a tube running straight through the box so that the operator looking through can sight it like a telescope, before the film is exposed. When the sighting and focusing are completed the opening is closed with a light-tight cap, and the film can be threaded through the camera. Having no bellows for focusing like an ordinary camera, the lens of the motion-picture camera is moved back and forward a short distance in the little tube in which it is set, to aid in the focusing. Of course the lenses of these wonderful snapshot machines are the best that money can buy and the factories can turn out.