MODEL AEROPLANES
After having taken in such a lot of information about aeroplanes the scientist's young friend considered himself fairly well equipped to build a flier.
"Why couldn't I build a little model aeroplane?" he said one day.
"No reason why young couldn't," answered his friend in the laboratory. "You have a little workshop at home and your own simple tools will be plenty. You will have to buy some of your materials, but they are all cheap.
"There is no sport like model aeroplane flying, but to the average American boy the flying is not half so much fun as meeting and overcoming the obstacles and problems entailed in making the little plane. These days nearly any boy would scorn to enter a model aeroplane tournament with any machine that he did not make himself, and a great many of the amateur aviators even prefer to make their own designs and plans.
"When we begin to take up the construction of a glider or an aeroplane, we must, like the Wright brothers, reluctantly enter upon the scientific side of it, because in model building we cannot simply make exact reproductions of the great man-carrying fliers, but must meet and overcome new problems. The laws that govern the standard aeroplanes apply a little differently to models, so it is necessary for the model builder to figure things out for himself.
"For instance," explained the scientist, "most amateurs have decided that monoplane models fly much better than biplanes. The reason for this is probably that with the miniature makes the air is so disturbed by the propeller that its action on the lower plane tends to make it unsteady rather than to give it a greater lifting capacity. This could be avoided by placing the two planes farther apart, but they would have to be so far separated that the machine would be ungainly and out of all proportion. Moreover, the second plane, with the necessary stays and trusses, adds to the weight of the machine, and this is always bad in models.
"There are as many different types of model aeroplanes as there are of the big man carriers, but you had better make a small flier first, experiment with it, and then work out your own variations just as you think best."
"Will you help me build one?" asked the boy.
"No, for you don't need my help and you will have more fun doing it alone. I will tell you how to go about it, and with what you know of the principles of aviation from our conversations it will be easy to make a successful model."
Then taking a piece of paper and a pencil the scientist began to draw rough plans for the building of a little model monoplane something like the Blériot, except that it was driven tail first, with the propeller at the rear. As he worked he explained how the plan shown below should be followed, saying that the beginner would find that a length of about one foot would be the most convenient for this first model. Later on he can make the big ones with a spread of wings of three feet, and a length of forty or more inches.
A SIMPLE MODEL AEROPLANE
First, the three main parts of the model should be made. Those are the two main planes and backbone. The simplest way of making the planes for a model of this kind is to use thin boards of poplar or spruce, which will not split easily and which can be worked with a jackknife. The large plane should be rectangular, with a spread of eight inches and a depth of two inches, while the smaller plane should be the same shape, four by one inch. They should be one eighth of an inch or less in thickness. Plane and sandpaper them down as thin and as smooth as possible without splitting them, and round off the corners just enough to do away with sharp edges. Now draw a line parallel with the side that is eight inches long, three quarters of an inch from the edge. Measure off two inches toward the centre from the outer edges, along this line, and draw lines parallel with the edges that are two inches deep. At the corners which are to be the rear we find the lines make two rectangles three quarters of an inch by two inches, and these corners are to be cut away in a graceful curve from the corners of the rectangles. When it is done the main plane will be shaped like a big D with the curved edge to the rear. The front edge of the small plane also should be curved, but not nearly so much as the larger plane. This done, the planes can be steamed or moistened with varnish, and given a slight curve or camber by laying them on a flat board with a little stick underneath and weights at the front and back to hold down the edges while they dry and set. The sticks should be about one third of the way back from the front edges, from there tapering down to the level of the rear edge. Of course, in this process great care must be used not to split the delicate planes.
STANDARD FARMAN BIPLANE
Note the box tail and the single elevating plane.
FARMAN PLANE WITH ENCLOSED NOSE
This type is sometimes used in Europe, and it led to the Farman "canard" with the box tail in front.
A MODERN BLÉRIOT
This machine has the enclosed fuselage and other recent improvements. Note the four-bladed propeller
A STANDARD BLÉRIOT
This is the regular type of Blériot made famous by long over-water flights.
PASSENGER-CARRYING BLÉRIOT
This type has tremendous capacity for carrying great weights.
There are many other ways of making planes. If one does not care to round off the edges, he can make very light wooden rectangular frames of the size indicated, and cover them with cloth, or silk, afterward varnishing them to make them smooth and air-tight. It is difficult to give such planes a camber, but if the framework is made of strong light wire, such as umbrella ribs, and then covered, the camber can be obtained by putting light wire or light wooden ribs in the planes, much like on the big standard makes. Plane building can be developed to a high art, and after a boy makes one or two models he will see any number of ways that he can make them lighter, stronger and more professional looking.
With the planes finished, the next work is to make the backbone of the machine by planing and sandpapering a light strong stick one foot long and not more than a quarter of an inch square. Cut out a neat block of the same wood, the same thickness as the backbone, and one inch square. Glue it to the end of the backbone and reinforce it by wrapping it with silken thread moistened with glue or varnish. Be sure to have the grain of this block, which is the motor base, run the same as the backbone. Three quarters of an inch from the backbone, and parallel with it, bore a little hole for the propeller shaft or axle. Unless you are sure of your drill, heat a thin steel wire and burn the hole, rather than risk splitting the block.
The propeller is the next thing to make, while the glue on the backbone is drying, and the camber of the plane is setting. Some models have metal propellers, but most boys prefer to make wooden ones, either from blocks of their own cutting or from blanks that can be purchased. The blank should be four inches in diameter an inch wide, and half an inch thick. It can be cut away very thin with a sharp knife, and a fairly good whittler can make a propeller that looks as businesslike as the great gleaming blades on the big machines. A wire then should be run through the dead centre of the propeller and bent over so that when the wire shaft turns the propeller also turns. As a bearing or washer the simplest device is a glass bead strung on the shaft and well oiled to lessen the friction, between the propeller and the propeller base. The shaft is then run through the hole in the motor base and bent into a hook for the rubber strands that drive the propeller. Great care should be taken in mounting the propeller and making the hook that the shaft is kept in an absolutely straight line, and at an accurate right angle with the propeller, so that the screw can turn free and true with as little friction as possible, and no wobbling or unbusinesslike vibration. Next a wire hook should be placed at the other end of the backbone upon which to hook the other end of the rubber strands. This hook can either be imbedded in another block the same size as the motor base or can be set out by some other ingenious device, so that the strands will turn free of the backbone, and will make an even line parallel with it. Both hooks should be covered by little pieces of rubber tubing to protect the rubber strands. Any friction whatever in a model is bad, but it is worst of all upon the rubber strands of the motor.
With the parts in hand the next step is attaching the planes to the backbone. In this machine the motor should be above the planes, so that the planes should be affixed to the upper side of the central stick, with the rubber strands above them. The propeller is at the rear, so the small front plane should be placed at the front, with the slightly curved edge to the rear. It should be about an inch from the tip of the stick and the front edge should be elevated slightly to give the necessary lifting power. The main plane should be placed about an inch from the rear tip of the backbone, with the curved edge to the rear and the front slightly elevated. The planes should be affixed with rubber bands so that it is possible to move them forward or back, because the little monoplane might be lacking in fore and aft stability and the rearrangement of the planes might correct it. It might even be found more satisfactory in some models to change the order and let the propeller, base, and strands of the motor come below the planes instead of above them. Your own experience will tell best.
THE ANTOINETTE MONOPLANE
New armoured Antoinette shown in the large picture, while the small insert shows the old-style machine.
Photo by Philip W. Wilcox
THE NIEUPORT MONOPLANE
Comparatively a new make, the Nieuport monoplane has sprung into great favour for its speed and passenger-carrying capacities.
Of course, the planes must be placed on the backbone exactly evenly or the airship will be lopsided, a fatal fault. By experimenting, the boy can tell just how high the front edges should be elevated, or, in other words, what angle of incidence he should give his plane. A rudder, to keep the machine in a straight course, can be added underneath the centre of the main plane. It should be about two inches square, but shaved off to a curving razor edge. Also light skids of cane or rattan may be added. They should be glued to the under side of the backbone and curved backward like sled runners. The front one should be two and a half to three inches high, while the rear one should be about an inch to an inch and a half less.
After trying out the model as a glider by throwing it across a room and making sure it is well balanced both laterally and longitudinally, or from side to side, and fore and aft, the rubber strands can be put on, and the motor wound up. About four strands of rubber one eighth of an inch square, such as is sold for this purpose, would suffice for good flights of more than one hundred feet, if the machine were of the same weight and proportions as the model from which this description was written. In models, however, there are many little details that can change the conditions, and a boy can only experiment, locate his mistakes, and try it over again.
This is one of the simplest and easiest model aeroplanes that can be made. A trip to one of the model aeroplane tournaments will reveal dozens of more elaborate ones, which will give any ingenious boy ideas for development of the principles he can learn from the simpler type. Probably the next step of the average boy would be to build a machine with two motors, which can be done by elaborating the single stick backbone or by making a backbone of two or three sticks well braced with cross pieces at each end and in the middle. Then there are interesting experiments with the size of planes, number of planes, their aspect ratio—that is the proportion of their width to their depth—ailerons for automatic stability, and rudders for keeping the machine on a straight course. There are always new things to be done with the motors, because, though the rubber motors have driven models close to half a mile, there are now on the market miniature gasoline motors to drive models, and experiments are being tried with clockwork and compressed air. Indeed the model aeroplane field is as broad in itself as that of the man-carrying machines.
Aviation has been reduced to an exact science, but it is yet in its early growth, both in the field of models and in the field of the various kinds of man-carrying machines. Not only are the designers making great headway with aeroplanes, but also with dirigible balloons so any one interested in aeronautics has a very wide field for his work. As we said in an earlier chapter, the boy model designer of to-day may be the inventor of to-morrow who gains undying fame by some now undreamed-of development of the aeroplane.
The designers of the man carriers are trying to make their machines stronger, safer, more reliable, capable of carrying more passengers, and they hope at last to bring them to a more practical use in the world than as a sport. The most thoughtful aviators do not favour exhibition flying so strongly as they do long cross-country flights, endurance tests, passenger-carrying tests, and other experiments that will develop aeroplanes beyond their present limitations.
The next great feat of the aeroplane is the crossing of the Atlantic Ocean, and that may not be far distant, for at the time of writing half a dozen aviators are planning the attempt, but even more important than that, even more important than the development of the aeroplane for war scouting, is the development of the aeroplane as a faithful servant of the people who are quietly going about their own everyday business. The time will come when the readers of this may send their mail by aeroplane, take pleasure rides in the aeroplane instead of the automobile, and even make regular trips on regularly established aeroplane routes, buying their tickets at the great central aeroplane stations as they would buy railroad tickets in the Grand Central or the Pennsylvania stations to-day, taking their seats in comfortably arranged aero cars, and being whisked in a few hours from one part of the country to the other, and even from one side of the ocean to the other.
CHAPTER IV
ARTIFICIAL LIGHTNING MADE AND HARNESSED
TO MAN'S USE
OUR FRIENDS INVESTIGATE NIKOLA TESLA'S INVENTION FOR THE WIRELESS TRANSMISSION OF POWER, BY WHICH HE HOPES TO ENCIRCLE THE EARTH WITH LIMITLESS ELECTRICAL POWER, MAKE OCEAN AND AIR TRAVEL ABSOLUTELY SAFE, AND REVOLUTIONIZE LAND TRAFFIC.
"HOW would you like to send a signal clear through the earth with your wireless outfit and get it back again on your receiving instrument as clear and strong as at first, just about the same way you hear the echo of your voice when it rebounds from a mountainside or a big building?" asked the scientist one day while his young friend was telling him about his amateur wireless experiments.
"I don't see how I could," answered the boy.
"No, of course you don't," said the boy's friend, "for it took Nikola Tesla, 'the wizard of electricity' almost a lifetime to work out the invention by which he could do that, but if you like we will go and see Doctor Tesla and ask him to tell us about his wonderful experiments.
"You see this is a series of inventions by Tesla, and wireless telegraphy is only a small part of it. You remember the other day you told me of having read about aeroplanes equipped with wireless. Just think, Tesla's invention will make it possible for airships to be propelled and operated all by electricity sent without wires. The whole broad plan is called the wireless transmission of power, and that simply means that electricity can be transmitted without wires for all the uses we now have for it, as well as for a number of entirely new and hitherto unknown devices."
The boy was delighted with the prospect of seeing the great scientist Tesla, about whom he had read so much, and began to ask his older friend a thousand questions about the man, his work and life.
It was a good many days before the whole thing had been talked over, and the boy understood the series of inventions, but we will follow through a part of our scientist's explanation and the visit to Tesla's laboratory and plant.
Although Tesla's plan is one of the most astounding ever proposed by science, it has been proved possible by experiments of such hair-raising nature that the inventor has been called a "daredevil" a "demon in electricity" and a "dreamer of dynamic dreams." In his experiments he has produced electrical currents of a voltage higher even than the bolts of lightning we see cleaving the sky during the worst thunderstorms. These currents he has harnessed to his own use and made them tell him the inmost secrets of the earth—in fact of the palpitation at the very core of the globe—the heartbeats of our sphere. He has given exhibitions in which he has caused currents of inconceivably high power to play about his head as if they were gentle summer breezes, and while working in the mountains of Colorado, he has brought forth electrical discharges which caused disturbances in the wireless telegraph apparatus in all parts of the globe.
In short, Nikola Tesla plans to make artificial lightning, and so harness it to the use of man, that it can be sent anywhere on or above the earth, without wires.
To scientists and electrical engineers, Tesla's plan offers a field for limitless study and discussion, but to the boy who is interested in electricity it offers one of the most fascinating subjects for reading and thinking in all the realm of science. Just reflect that with the wireless transmission of power, and the development of an art that Tesla calls "telautomatics," the navigators of wireless power-driven airships and ocean liners will know their exact speed, position, altitude, direction, the time of night or day, and whether there is anything in their path, all through the wireless "telautomatic" devices for registering such impressions.
Tesla declares that the terrible Titanic disaster never would have occurred had his system been in effect last April, for he declares that the Titanic's captain would have known of the iceberg he was approaching long enough in advance to slacken speed and get out of its way. Moreover, he declares that with the wireless transmission of power, the wireless telegraph becomes a very simple matter, and that immediately after the accident, had the ship struck an obstacle in spite of warnings, the captain could have been in wireless telephone communication with his offices in London and New York, and with all the ships that were on the seas in the vicinity of the ill-fated liner.
But making air and sea navigation safe, sure, and speedy, are only the first steps Tesla intends to take in the wireless transmission of power. After that he hopes to light the earth—to carry a beautiful soft bright light to ranchmen far out on the deserts, to miners in their cabins or deep in the earth, to farmers, and to sailors, as well as to people in their homes in the cities all over the world—Australia as well as the United States.
Wireless electrical power, according to Tesla, will be one of the greatest agencies in war, if there is any, but it first will be an argument for universal peace. "Fights," says the inventor, "whether between individuals or between nations arise from misunderstandings, and with the complete dissemination of intelligence, constant communication, and familiarity with the ideals of other nations, that international combativeness so dangerous to world peace, will disappear."
If Tesla's plan were carried out in full it would completely revolutionize the industries of the world, for all the power of Niagara or any other waterfall in the world could be sent without wires to turn the wheels of the industries in China or Australia, while the power of the Zambesi Falls in Africa could be transmitted to run trains, subways, elevateds, and all other forms of industry in the United States. There is practically no limit to the possibilities of the scheme, because through Tesla's invention, distance means nothing, and the power instead of losing force with distance as is the case when power is transmitted through wires, retains practically the same voltage as at the outset.
We will visit Doctor Tesla at his office and laboratory in the Metropolitan Tower in New York with the scientist and his young friend to see what kind of a man it is who has invented machines for creating and handling such tremendous voltages.
Tesla sits at a wide flat-topped desk in the centre of his sunny office surrounded by books, a few models of inventions, and a few pictures of some of his most remarkable electrical experiments. He is very tall and slight, with a mass of black hair thrown back from his intellectual forehead. His piercing gray eyes sparkle as he smiles in greeting, and his thin pointed face lights up with an expression of pleasure and kindness that cannot help but make the great electrician's visitors feel that he is a good friend. Although he was naturalized more than twenty years ago, and has been an American citizen ever since, his English still shows some slight traces of his foreign birth. He looks no more than forty-odd and he is as interested in everything that is going on in the world as a young boy, but he has passed his fiftieth year.
"For all that I am something of a boy still myself," says the inventor. "You see I could work for the present generation to make money. Of course that's all right, but I don't care what the present generation thinks of me. It is the growing generation—the boys of to-day that I want to work for, because they will live in an age when the world has advanced far enough in science to understand some of the deeper mysteries of electricity. The boys of to-day are the great scientists of to-morrow, and it is to them that I dedicate my greatest efforts."
All his life Tesla has been working with an eye to the future as well as to the present, and some of his inventions probably will be far better appreciated in twenty years than they are now, although to Tesla we owe our thanks for some of the most important electrical machinery in use at the present time.
As an inventor Tesla is best known as a pioneer in high tension currents. It was he who introduced to the world the great principle of the alternating current, as up to the time he carried out his experiments only the direct current was used. Indeed, more than four million horsepower of waterfalls are harnessed by Tesla's alternating current system. That is the same as forty millions of untiring men working without pay, consuming no food, shelter or raiment while labouring to provide for our wants. In these days of conservation, it is interesting to note that this electrical energy derived from water power saves a hundred million tons of coal every year. Our trolley roads, our subways, many of our electrified railroads, the incandescent lamps in our homes and offices, all use a system of power transmission of this man's invention.
As said before Tesla is a naturalized American citizen. He was born in Smiljan, Lika, on the Austro-Hungarian border, in 1857. He came by his scientific and inventive turn of mind naturally, for his father was an intellectual Greek clergyman, and his mother, Georgia Mandic, was an inventor herself as was her father before her. The boy attended the public schools of Lika and Croatia, where he was a leader among his playmates in sports where imagination and mechanical skill were required. There are marvellous tales of the ingenuity of Tesla while a schoolboy, but with all his play he was a serious-minded student, and went through the Polytechnic in Gratz and the University of Prague in Bohemia with honours. While in the Polytechnic, Tesla saw the defects of some of the machinery that was used in the laboratory, and made suggestions for its improvement.
After finishing college Tesla began his practical career in Budapest as an electrical engineer in 1881. His first invention followed soon after in the form of a telephone repeater. He continued in electrical engineering in Paris until 1884, when he came to the United States. His first employment in America was with The Edison Company at Orange, N. J., but in 1887 he went into business for himself as an electrical engineer. From that time on he has been an important figure in the scientific world. He has made many addresses before various gatherings of experts and has written numerous papers on scientific subjects for the magazines. Of course the bulk of his time has been given to his inventions and the necessary research therefor.
LIKE A BOLT OF LIGHTNING
The electrical discharge of this Tesla oscillator created flames 70 feet across, under the pressure of 12,000,000 volts and a current alternating 130,000 times per second.
DR. NIKOLA TESLA
Wizard of electricity, and inventor of the wireless transmission of power.
DOCTOR TESLA'S FIRST POWER PLANT
From this oscillator Doctor Tesla sends out the electrical waves with which he hopes to revolutionize industry.
Throughout his life Tesla has been more interested in the adventurous and scientific side of electricity than the commercial side, and all of his inventions smack of the marvellous. To name all his inventions would be almost like giving a list of the machines and devices that mark man's progress in the use of electricity. His invention for the alternating current dynamo, for instance, brought forth an entirely new principle, while his rotating magnetic field made possible the transmission of alternating currents from large power plants over great distances and is very extensively used to-day. High power dynamos, transformers, induction coils, oscillators, and various kinds of electric lamps all came in for his attention.
He became one of the foremost authorities on high tension currents and in 1889 invented a system of electrical conversion and distribution by oscillatory discharges which was a step toward his great goal, the wireless transmission of power. He was very near the prize when in 1893 he announced a system of wireless transmission of intelligence. His studies continued and finally, in 1897, he announced his famous high potential transmitter by which he claimed to be able to send power through the earth without wires. The art of telautomatics announced in 1899 was really a part of Tesla's invention for the wireless transmission of power, for the plan was to control such objects, for instance, as airships or boats, from a distance by electricity transmitted without wires.
Through that marvellous invention the boat or aeroplane dispatcher, sitting before a complex little wireless dispatching board could send his craft, at any speed, at any height, in perfect safety, and with exact precision to the place or port he desired it to go. It would not be necessary for the dispatcher ever to see the craft he was directing, for his instruments would show him everything in regard to its speed, direction, and location; nor yet would it be necessary for a craft to have a crew aboard, for all the operations in connection with sending it from one place to another would be controlled perfectly by telautomatics.
Such are the almost inconceivable inventions of Nikola Tesla. "Sometimes they call me a dreamer," says Tesla, "because I do not capitalize these inventions, start in manufacturing and make a big fortune. That is not what I care to do. I want to go further in this great mystery of wireless power, and if I am busy making money I cannot devote my best abilities to inventions that will be in use when the next generation is grown."
But let us try to fathom the mysteries of Tesla's scheme for the transmission of electric energy without wires. In the first place we must not try to think of it as being on the same basis as the radio, or Hertzian wireless telegraph, for, although the modern developments of the wireless telegraph take into consideration the central theory of Tesla's invention, they are not at all the same in their practical working.
Tesla's theory is based entirely on his discovery of what he calls stationary electrical earth waves which he sets in motion with his high potential magnifying transmitter, an electrical apparatus of tremendous power.
First, let us remember the three essential departments of Tesla's idea for world telegraphy, world telephony, and world transmission of power for commercial purposes.
Assuming that the power is created by Niagara or some other great waterfall—"white coal" as it is picturesquely called by many engineers—the first necessities are a transformer and a transmitter that will send the electrical energy, thus gathered, into the earth and air. The next necessity is a receiving instrument that will record the impulse, whether it be a voice, a telegraph click, or several million volts for driving factory wheels or lighting houses. Lastly, it is necessary to tune the currents so that millions of different impulses can be sent without causing confusion between them. In other words, there must be departments for sending, receiving and "individualizing."
To ask Doctor Tesla to tell us the whole story of this invention would be to ask him to tell us in detail the whole history of his life work—and that would take several volumes, for he is one of those men who have worked incessantly, day and night, sacrificing himself and overcoming his natural desire for leisure and amusement. It all started, Tesla explains, when he was a very small boy. He was troubled at that time with a strange habit. Whenever any one would mention a thing to him, a vision of the object immediately would come before his eyes. He declares that this was very troublesome, and that as he grew older he tried to overcome it, thinking it some strange malady. With an effort he learned how to banish the images by putting them from his mind. On inquiring into the cause of the visions, the young scientist's penetrating brain brought him to the conclusion that every time he saw a vision, some time previous he had seen something to remind him of the object. The tracing back of the cause of his vision so frequently caused it to become a mental habit, and he declares that for many years he has done it automatically, and that he has been able to trace the cause of nearly every impression, even including his dreams. Reflecting on these things, as a mature scientist, Tesla came to the conclusion that he was an automaton, responding automatically to impressions registered on his senses from the outside.
"Why couldn't I make a mechanical automaton that would represent me in every way, except thought?" he asked himself. The answer to the question which came only after years of study and experiment was the art of "telautomatics," which Tesla declares can be developed just as soon as the wireless transmission of power is an accomplished fact.
In the course of his research into the realm of high tension currents Tesla reached the stage where it was no longer safe nor convenient to experiment in the centres of population. Moreover, he desired to make a study of the action of lightning. Colorado, with its vast stretches of uninhabited plains and mountains, offered an ideal place for his laboratory, particularly because the high, dry climate of that state brings forth some of the worst electrical storms seen in the United States. Consequently, in the spring of 1899, Tesla built an experiment station on the plateau that extends from the front range of the Rocky Mountains to Colorado Springs, and began the experiments through which the secret with which he hopes to revolutionize the communication and transportation systems of the world, was revealed to him.
Besides his high power alternating current dynamo, Tesla set up an electrical oscillator with which he hoped to send out electrical waves, through the earth and air, that would prove to him the possibility of an extensive system of wireless communication, and telautomatic, or wireless control of airships, projectiles, steamships, etc. In his early experiments he used the oscillator at low tension, but as his success became more marked he increased the tension, until the oscillator was giving twelve million volts, and the current was alternating a hundred thousand times a second.
In regard to these high tension experiments in Colorado and elsewhere, Doctor Tesla said, "I have produced electrical oscillations which were of such intensity that when circulating through my arms and chest they have melted wires which have joined my hands, and still I have felt no inconvenience. I have energized, with such oscillations, a loop of heavy copper wire so powerfully that masses of metal placed within the loop were heated to a high temperature and melted, often with the violence of an explosion. And yet, into this space in which this terribly destructive turmoil was going on I have repeatedly thrust my head without feeling anything or experiencing injurious after effects."
Among the earlier experiments, which in themselves were wonderful enough, were the transmission of an electrical current through one wire without return, to light several incandescent lamps. Advancing further along the trail of wireless transmission of power, Tesla lighted the lamps without any wire connection between them and his transmitter.
The oscillator, though simple in its construction, is one of the most wonderful of all electrical devices. "You see," said Doctor Tesla, "all that is necessary is a high power alternating dynamo which generates a tremendous alternating current. For our oscillator proper, we make a few turns of a stout cable around a cylindrical or drum-shaped form, and connect its two ends with the source of electrical energy. Then, inside the big cable, or primary coil, we wind a lighter wire in spiral form. One end of the secondary coil is sunk into the ground and connected with a plate, and the other is erected in the air. When the current is turned on, our oscillator sends these electrical impulses into the earth and air—or, as the scientists say, into the natural media. These oscillations create electrical waves and affect any device that is tuned to them—but (and this is very important) no device that is not tuned to them."
Continuing the explanation of his high tension experiments, Tesla tells us that the awe-inspiring electrical display, of which there is a picture on page [136], was made by his oscillator which created an alternate movement of electricity from the earth into a hollow metal reservoir and back at a speed of 100,000 alternations a second. The reservoir is already filled to overflowing with electricity and as the current is sent back to it at each alternation the terrific force makes it burst forth with a deafening roar, as great as the heaviest lightning detonation. The electric flames shoot out in every direction searching for something on which they may alight, just as lightning sent from the clouds searches for a conductor upon which it may alight and escape into the earth. The induction coils in the picture are tuned to these tremendous electrical explosions, and the flames shoot direct to them, a distance of 22 feet.
The flames shooting from the coil of the oscillator pictured on page [164] were nearly 70 feet across, represented twelve million volts of electricity, and a current alternating 130,000 times a second. These hair-raising experiments created such electrical disturbances that it was possible to draw great sparks more than an inch long, from water plugs over 300 feet from the laboratory. One of the most marvellous things about these experiments is that any human being could remain in the vicinity. The absolute safety of these discharges when properly harnessed is well illustrated in the picture shown there as the man seen amidst the flames felt no ill effects from his experience, simply because this power was so thoroughly harnessed by the wizard Tesla, that it could go only to the device tuned to receive it. Every boy is familiar with stories of lightning striking one person, but yet leaving another person right next to him unharmed. Such is the action of Tesla's high tension currents, only he directs them by induction just as he wants them to go.
"But this is just like lightning!" exclaimed the boy.
"So it is," calmly answered Doctor Tesla with a smile. "I have often produced electrical oscillations even greater than the energy of lightning discharges."
These experiments were marvellous enough, but they were surpassed in a short time by his famous discovery of July 3, 1899, which showed him that he could send his wireless waves to the opposite side of the earth just as well as a hundred feet away.
This revelation, as the scientist calls it, came about through his study of lightning. The scientist had set up in his Colorado laboratory many delicate electrical instruments to register various different electrical effects. Tesla noticed, however, that strangely enough his instruments were just as violently affected by distant electrical storms as by nearby disturbances.
"One night when meditating over these facts," said Tesla, "I was suddenly staggered by a thought. The same thing had presented itself to me years ago; but I had then dismissed it as impossible. And that night when it recurred to me I banished it again. Nevertheless, my instinct was aroused, and somehow I felt that I was nearing a great revelation.
"As you know, it was on the third of July that I obtained the first definite evidence of a truth of overwhelming importance for the advancement of humanity. A dense mass of strongly charged clouds gathered in the west, and toward evening a violent storm broke loose which, after spending much of its fury in the mountains, was driven away with great velocity over the plains. Heavy and long persisting arcs formed almost at regular intervals of time. My observations were now greatly facilitated and rendered more accurate by the records already made. I was able to handle my instruments quickly, and was prepared. The recording apparatus being properly adjusted, its indications became fainter and fainter with the increasing distance of the storm, until they ceased altogether. I was watching in eager expectation. Sure enough, in a little while the indications again began, grew stronger, gradually decreased, and ceased once more. Many times, in regularly recurring intervals, the same actions were repeated, until the storm, as evident from simple computations, with nearly constant speed had retreated to a distance of about two hundred miles. Nor did these strange actions stop then, but continued to manifest themselves with undiminished force.
"When I made this discovery I was utterly astounded. I could not believe what I had seen was really true. It was too great a revelation of Nature to accept immediately and unhesitatingly."
What Tesla had discovered, and soon announced to the scientific world, was the existence of stationary terrestrial waves of electricity, and its meaning was that an impulse sent into the earth was carried on these waves to the other side of the earth and rebounded without any loss of power. He had, in fact, discovered and turned to man's use the very heartbeats of our earth.
"Whatever electricity may be," he continued, "it is a fact that it acts like a fluid, and in this connection, we may consider the earth as a great hollow ball filled with electricity." He goes on to explain that when an impulse is sent into this ball of electricity it proceeds to the opposite wall of the earth in waves and, finding no outlet it returns to the place it started, but in a series of waves exactly the opposite of the outgoing ones, so that the two cross and diverge at regular intervals as indicated in the diagram.
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 is just 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 first steps 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 that this 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 wireless telegraphs 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 instrument below 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 tapping the 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 the Republic and Titanic disasters. But also we know that the wireless can be greatly improved upon. With a perfect system of communication, both by wireless telegraph and telephone, 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 the Titanic?" 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 will answer 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 San Francisco 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 future material 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, carry our 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 soon enable 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 combination of 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 V
THE 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 based on 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 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 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 are not 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 out illusion of 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, buildings burning 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 magazine The World To-day (now Hearst'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 between there 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-picture studios 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 cinematograph films 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."
Thomas A. Edison, inventor of the motion-picture machine.
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 of an 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-picture operator 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 page [176]. 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, and that 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.
A SECTION OF MOTION-PICTURE FILM
This is the exact size of the little pictures we see on the screen almost life size. Note how slowly the changes appear. It takes only one second to take sixteen of these.
Courtesy of Thomas A. Edison, Inc.
MAKING A MOTION-PICTURE PLAY IN THE STUDIO
Note the photographer, the stage manager beside him, and the battery of arc lights making the scene in the studio as light as day.
In the rear half of the camera are two boxes. The top one holds the unexposed roll of negative, while the exposed film is rolled in the bottom one. Roughly speaking, the film unwinds from the top spool, passes out of the containing box through a slit, over a set of sprockets into the "film gate," down past the lens and shutter, where it is exposed over a lower set of sprockets, and through a slit into the lower containing box, where it is wound on a spool.
A MOTION-PICTURE CAMERA
A —Box for coil of unexposed film. A´—Box for coil of exposed film. B —Film passing over rollers. B´—Exposed film passing over rollers. C —Cogwheel which draws out film. D —Teeth which jerk film past lens. E —Lens and film-gate. H —Cogwheel which draws in exposed film.
"It looks simple enough, doesn't it?" asked the photographer, who was explaining the making of a moving-picture play to his visitors. "Well, it is a simple idea, but it takes a very complicated and a wonderfully accurate machine to accomplish the desired result.
"In the first place our cinematography is just still photography at high speed. We have to take approximately sixteen snapshots a second, so you can see that it takes a perfect machine to move the film along fast enough so that we can get sixteen good, clear, sharp pictures only slightly bigger than a postage stamp, on our film between the ticks of your watch.
"Now if you look through the little hole at the back of the camera you will see that the scene in front of us is in the proper focus, and if you look at the little ground glass finder at the side here you will see it just the same way, except that it will be upside down. Now I will close the telescope focus at the rear so that when the film is brought down before the lens it will not be light struck."
The "threading" of the camera then began. "This little flap sticking out of this slit in the top box," continued the cinematographer, "is the end of the film, which is tightly wound up in its holder. You notice that I draw it out and thread it between these rollers, making sure that the teeth of the sprockets enter the perforations along the sides of the film. I also make sure that the sensitized side of the film is turned out, so that the light coming through the lens will strike it first. After the negative has been led over the sprockets you notice that it is allowed to make a loop of a couple of inches of slack. Then it is led into the important device we call the 'film gate.'
"You see the gate is hinged and that these little claws or fingers running in grooves take hold of the perforations. The next thing is to close the hinged gate so that the film is tightly held against the aperture, through which the light strikes it and makes the picture. Below the gate we let the negative make another loop and then thread it over another system of rollers and sprockets and so to the slit in the lower box, where the exposed negative is rolled.
"The camera is now loaded and threaded and when I give the crank by which the wheels are turned a few trial turns you can see the way the mechanism works. In the first place you must understand that the film has to be jerked down with an intermittent motion. Don't forget to look for the intermittent motion, because, after the persistence of vision, that jump and stop, jump and stop, is the most important thing in cinematography—intermittent motion!
"You can see as the crank turns that the sprockets pull the film out and guide it along its course, and the little fingers jerk it down the space of one picture, or three quarters of an inch, at each jump. When the fingers are jerking the negative down, the shutter must be closed, and when the fingers are making their back trip to take a new hold on another length of film the strip must be as still as the Washington Monument, for the shutter to open, let in the light and transfer the image before the lens to the negative."
The photographer turned his crank and all the wheels in the camera began to move. The sprockets working in the perforations pulled out the film and made the loop larger. The little fingers entered the perforations and jerked the film down, taking up some of the slack of the loop. The reason that the loop is formed is to prevent the film being torn by a hard jerk by the fingers when it is taut.
"Now if your eye were quick enough—which it is not"—said the photographer, "and you could see behind the gate, you would see a movement like the following repeated sixteen times to the second: Crank turns, top sprocket adds three quarters of an inch to the top loop, bottom sprocket takes up three quarters of an inch of bottom slack loop, fingers spring from groove and carry film down three quarters of an inch, inconceivably short pause while shutter opens and picture is taken; during this pause, while film is stationary, fingers jump back into groove, slide back to starting point without touching film and shutter closes. The shutter is a revolving disk between the lens and film, and the holes in the disk passing the negative admit the light."
After a roll of negative film has been exposed it is sent to the studio dark room for development. Every precaution is taken, of course, that no ray of light other than that which comes from the ruby lamp shall enter this room where films representing hundreds, and perhaps thousands, of dollars are being developed. The actual process for developing is no different from that used in developing other films, but the difficulties in handling a delicate snakelike, strip some 300 or 400 feet long and 1-3/8 inches wide are tremendous. All amateur photographers appreciate the difficulties of developing in one string a roll of twelve films of a reasonable size, but think of handling a roll of film several hundred feet long no wider than a ribbon, and holding sixteen pictures to each foot of surface!
The difficulties of scratching, tangling, etc., were overcome by systematizing the process. In some cinematograph dark rooms the films are wound on racks about four by five feet, and then plunged into the various baths, which are in vertical tanks of convenient size. In yet other dark rooms the films are wound upon drums about four feet in diameter and revolved in horizontal tanks, only the lower part being immersed. The only difference is that the racks can be manipulated easier than the drums.
While in the motion-picture dark room the boy visitor asked the photographer in charge whether an amateur could step in and develop a few hundred feet of film granted that he had the necessary materials.
"Of course he could," came a cheerful voice from the darkness. "It's just the same as developing a roll of ordinary films, only we do more in a bunch than the amateur. If you'll step over here and watch this reel that we are now putting into the developing bath you'll see that it does just the same as the single film developed in the amateur's dark room." After watching this trained photographer and his assistant for a few minutes, however, the newcomer decided that it was not an amateur's job, but rather one of the most delicate operations in all cinematography, for the developer can remedy many faults of exposure by bringing out an under-exposed film or toning down an over-exposed one.
Leaving the dark room the next stage of the negative is the drying room, where the film still on the rack is hung up to dry. This drying is a very difficult process because there is great danger of the film either becoming too brittle and cracking or of its being not hard enough. The air in the drying room has to be kept at a certain even temperature and it must be filtered so that no dust or impurity can injure the film.
After it has been properly dried the film again is wound upon a metal spool, put in an airtight box and sent to the assembling room, where the various scenes that go to make up the picture play, taken at different times and on different rolls of negative, are joined together in their proper order to make a complete play in a single roll about one thousand feet long.
After the negative film is developed, dried and wound upon a metal spool it is sent to the printing room, where positive prints are made from the original impression. Right here it may be well to say that on a negative film or plate in any kind of photography white appears black and black appears white—hence the name negative. The paper or film upon which the print is to be made turns black wherever the light strikes it, so that when the negative is laid over the positive and exposed to a strong light the rays quickly penetrate the white spots on the negative and turn the corresponding spots on the positive black. The light does not penetrate the places on the negative which are black, and consequently leaves those places on the positive white. The result is that the positive shows the image just as it appears to the eye.
The principle of printing positive films, then, is the same as the principle of making photographic prints or positives from ordinary still photography plates or films, but of course it is far more complicated because of the mechanical difficulties of bringing the two long, unwieldy strips of film together in the proper position. The whole process is carried out by a machine which takes the place of the printing frame into which the amateur so easily puts the still-life photographic plate and printing paper.
There are several motion-picture printing machines in use in this country, but in their central idea they are similar, as they all pass the negative and positive films before a very bright light so that the impressions on the negative are transferred to the positive. The invention of this machine was a necessity for the commercial success of motion pictures, for obviously it was impossible to lay a strip of film several hundred feet long and about an inch wide in a printing frame over a positive film of the same length and width.
A MOTION-PICTURE PRINTING MACHINE
A-A´—Rollers for negative film. B-B´—Rollers for positive film. C—Film gate where positive is held over negative for printing. D-D´—Negative film. E—Unexposed positive film. E´—Exposed, or printed positive film. F—Light which, shining through film gate, imprints image of negative on positive
The explanation of one printing machine will suffice to indicate the general principle. Some of the machines are worked by hand power, but in the larger reproduction studios electric power is used practically altogether for running the battery of printing machines.
The spool of negative film is slipped on to a spindle so that it can unwind easily, and immediately underneath it the roll of unexposed positive film, properly perforated along the edges in exactly the same way that the negative film is perforated, is suspended on a similar spindle. Of course the only light in the printing room is the photographer's ruby lamp.
The two films unwind and pass downward, with the sensitive surfaces to the inside, and the positive on the outside of the negative. They are drawn together, and with the positive stretched flatly over the negative they pass over a pair of smooth rollers and toothed sprockets which enter the perforations of the two films with mathematical accuracy. They then make a small loop and enter a side hinged gate which holds them tightly against the printing aperture. This aperture is a hole just the size and shape of each picture on the film, and through it shines a very bright light which casts its direct rays upon the negative and imprints the image of the negative film upon the sensitized surface of the positive film. After passing the printing aperture, the two films make another small loop, run down to another toothed sprocket wheel and roller, and then separate, the printed positive being rolled upon one spool and the negative upon its spool below.
The action of this machine is very similar to that of the motion-picture camera, for like the device for taking the photographs, the movement must be intermittent in order to obtain good results.
If the operator desires to see whether the two films are in exactly the right position and everything is going smoothly, he can, by the use of a lever in the printing gate, drop a little red screen between the light and the films, and by looking through the hole see through the unprinted positive, and the developed negative, to the light inside.
After a roll of positive has been printed, it is developed by just about the same process as is used in bringing out the images on the negative film. Then, after it is dried, the various scenes are joined together, titles and sub-titles put in, any final editing that is necesary is done, and the positive film is ready to be put on the projection machine for the first trial.
The preparation of the titles, sub-titles, and other explanatory writings that are thrown on the screen in the course of a cinematograph play is a comparatively simple matter. The words are written or printed out in large letters on cards and photographed by a camera with a slower movement than the ones used for recording moving figures. The positives are made from the negatives so taken, in the same way that positives of other films are made, and after development and drying are ready to be joined to the film in the proper places.
Every firm engaged in the fascinating business of making and reproducing cinematographic plays gives the most careful and painstaking attention to the first "performance" of a film. Of course it is held in private before only the officials and a few critics invited for the exercise of their judgment. The event amounts to the same thing as the dress rehearsal of a play to be reproduced upon the stage, and any changes that are necessary in the judgment of the critics cause just about as much trouble. Any one of a hundred things may be wrong. Some little incongruous detail in the scenery may be noticed, some jarring gesture by an actor or a scene in which the action does not proceed fast enough.
If the officials of the firm decide that a film is below their standard, parts must be cut out, and new parts photographed over again until the whole thing suits requirements. Sometimes one scene must be done over many times before it suits exactly, and several hundred feet of film wasted. At a cost of about three cents a foot, it is plain that the waste in film alone is great, but when a big scene with a hundred or so actors in it has to be done over again, the cost of assembling the company, paying their salaries and other expenses is enormous.
Finally, when the officials themselves are satisfied with a film it is thrown on the screen for the board of censors in the various cities, and if it measures up to standard, and contains no objectionable features, it is ready for public reproduction.
When all this is done, the printing machine again comes into play, and as many prints of the negative as are needed are struck off, for in cinematography, as in still photography, it is a simple matter to run off as many prints as are desired, once a good negative is made. These prints then are sent out to as many theatres, in as many different cities, as desire them, and released for public view on the same day in every theatre in the country.
Having looked at the motion-picture camera, and at the complicated process for developing and printing the films, we are now ready to climb into the little fireproof box from which comes the beam of light that throws the pictures on the screen. This is the projector and it is probably the most complicated of all the machines used in cinematography. As it was a development through the application of well-known mechanical principles we will not go into this subject more deeply than merely to understand its central principle, which is intermittent motion.
The result toward which the inventors worked was a magic lantern such as was familiar to every boy ten years ago, that would throw upon the screen the tiny consecutive pictures on the film, with such speed, and at the same time so clearly and steadily, that the effect would be that of figures in motion. Most boys will remember the flickering, flashing and jumping that used to be noticeable in motion pictures, and many are probably aware that it was the improvement of the projecting machine that did away with these objectionable features.
The essential parts of the projecting machine are the lantern with its light and lens, and the device for running the positive film before the light with the proper intermittent motion. It might be said generally that the projecting machine looks like a magic lantern, but on close examination it will be seen to be an extremely complicated affair.
The powerful electric light, usually an arc light, which is placed in a metal box a few inches behind the rest of the projector, directs its rays through the glass condensers, thence through the film, and thence through the lens, which throws the image upon the white screen or curtain. The condensers are made of two carefully ground glass parts. The first is dish shaped, with the concave side turned in toward the light and the convex side turned outward. Immediately against it is another condenser the same diameter and convex on both sides so that the collected rays from the dished part are shot forward to a point where they will all converge. This point is the centre of the lens. From the lens the rays of light are projected in a widening beam to the white screen on which the pictures appear.
The film is passed before the beam of light at a point between the condensers and the lens, so that the image is projected through the lens. The film is run before the light with the figures upside down, like in the ordinary stereopticon, and the lens turns the image right side up again.
The most interesting part of the solution of the problem is the advantage taken of the persistence of vision. Photographed at the rapid rate of sixteen a second, and thrown upon the screen at the same rate of sixteen a second, it is plain that the stage of motion shown in the pictures every sixteenth of a second is reproduced. With the inability of the eye to tell that the screen is merely exhibiting separate photographs, the appearance is of motion. In most persons this visual persistence is only about one twenty-fourth of a second, but that is long enough to allow animated photography to be a pleasing illusion to them, for it gives the shutter of the projector time to hide one picture while the mechanism moves the film down to the next picture, bring the film to a dead stop, and let the shutter open again to reveal the next stage of animation.
The manner in which modern mechanical skill took advantage of this physiological defect, proved many years ago by the leading scientists, is nearly as interesting as this slight defect in nature's own camera—the eye.
Above the film gate is a metal fireproof box (many of them are lined with asbestos) in which is the roll of unprojected positive film. Below it is another similar box in which the film that has been shown is wound. The motion, which is directed either by a crank turned by hand or by electrical power, is the same speed, and practically the same in detail, as that of the film in the cinematograph camera. From the film box the film runs to a roller, where a sprocket enters the all-important perforations and draws out the strip to make a small loop above the film gate.
The shutter is placed in front of the lens. It is made up of a black metal circular disk, with either two or three open spaces, and a similar number of solid or opaque spaces. In general it looks like a very wide flat aeroplane propeller. Like the movement of the camera, the film is stationary while the shutter is open, and when the shutter is closed the film is jerked down three fourths of an inch, or the length of one picture, and brought to a dead stop by the time the shutter revolves and is open again. This is repeated sixteen times every second, so the film is cast upon the screen for one thirty-second part of a second, and the screen is blank one thirty-second part of a second while the shutter is closed and, as we might say, the scenes are being changed for the next act. Although the movement is just the same as in the camera, it may be well for the sake of making the thing perfectly clear to go through the motion very slowly.
For the sake of keeping out of fractions entirely too small for our consideration we have assumed that in both camera and projecting machine the shutter is open one thirty-second part of a second and then closed one thirty-second part of a second, the whole operation taking one sixteenth of a second. As a matter of fact the effort of the experts in animated photography is to have the shutter of the camera open for just as brief a space of time as possible, and on the other hand it is their effort to have the shutter of the projecting machine open just as long a space of time as possible, and closed as short a time as possible. In other words, they desire to shorten the time when there is nothing on the screen, and lengthen the time for the eye to photograph each image on the brain. By using a little different mechanism in the film gate of the projector this is accomplished to some extent, as well as obtaining a clearer, steadier picture than formerly was shown.
You will remember that in the camera and printing machine the film was jerked down by little teeth or fingers.
The simpler of the two methods in general use on projectors now is called the "dog" movement. It is composed of an eccentric wheel placed below the film gate, with a little roller projecting from it. The wheel revolves and once every sixteenth part of a second the roller is brought around so that it strikes the film and jerks it down the three fourths of an inch that makes the space of one picture.
A MOTION-PICTURE STUDIO
This is where a great many of the Edison Photoplays are made. Besides all the other departments there is room on the stage for several different plays to be photographed at one time.
Courtesy of Thomas A. Edison, Inc.
A REALISTIC FILM OF WASHINGTON CROSSING THE DELAWARE
This picture was taken in zero weather on a real stream with real ice menacing the actors in the boats.
The other method is known as the "Maltese Cross" movement. The name is taken from the fact that the chief sprocket wheel is shaped somewhat like a Maltese Cross. This wheel, with four notches in it, is attached to the sprocket below the film gate, and it is driven intermittently by a wheel with a pin that enters one of the notches on the Maltese Cross wheel at each revolution, and pushes it around the space of one quarter of a turn. This of course turns the lower toothed sprocket and jerks the film down the space of one picture. On the next revolution of the driving wheel the pin enters the next notch, turns the Maltese Cross wheel another quarter of a turn, and, by the motion imparted to the sprocket, jerks the film down another three quarters of an inch, thereby pulling another picture into place as the shutter opens.
Recent improvements on this movement have largely done away with the jar resulting from the pin catching the notches in the cross. The wheel that looks like a Maltese Cross has, instead of four notches, three grooves, dividing the wheel into three equal parts just as if a pie were cut into three equal parts but the knife stopped short, leaving a solid hub in the centre. The space between each groove represents the length of one picture on the film. Without going into a long, tiresome, technical explanation of this very important little feature of the projecting machine, it will suffice to say that the three-groove wheel is connected with the sprocket underneath the film gate. Near it is a revolving arm, and upon this arm is a horizontal bar. When the arm makes a revolution, and reaches a point where it touches the three-divided wheel, the mechanical adjustment is so fine that the horizontal bar enters the groove, and the revolution of the arm carries the three-divided wheel around one third of a revolution—or the space from one groove to another—turns the sprocket and pulls the film down the space of one picture, with a quick steady pull. After getting this far, the arm on its upward course leaves the three-divided wheel, which stands still while the shutter is open until the arm gets around again, and as the shutter closes pulls the sprocket around another space.
The strong light concentrated upon the film, in just the same way that you concentrate the sun's rays upon your hand with a burning glass, is very apt to set the film afire, particularly if through any slip in the machinery it stops in its rapid progress of about a foot a second. As machinery is not infallible, the manufacturers have invented various safety devices for protecting the film in case the machinery stops. Of course this is not necessary when non-inflammable film is used.
CHAPTER VI.
ADVENTURES WITH MOTION PICTURES
PERILOUS AND EXCITING TIMES IN OBTAINING MOTION PICTURES.—HOW THE MACHINE CAME TO BE INVENTED, AND THE NEWEST DEVELOPMENTS IN CINEMATOGRAPHY
WITH a clear understanding of the mechanism of the various motion-picture machines in mind, we are free to go on with the scientist and our young friend to the exciting times experienced by actors and photographers in making the pictures that delight people all over the world. First, however, let us briefly look back over the history of the art, for there is nothing more interesting than to follow up the experiments upon which Thomas A. Edison based his invention of the original cinematograph or kinetoscope.
Long ago, even before Edison was born, scientists tinkered with devices that would picture apparent motion, but they were rude attempts and little progress was made for many years. The first man to take a decisive step toward practical cinematography was Edward (or Eadweard) Muybridge, a photographer who lived in Oakland, Cal.; so he is rightly called the father of motion pictures.
Muybridge had been experimenting with snapshot cameras, as in those days instantaneous photography with wet plates was comparatively new, and, being something of an artist as well as a photographer, he decided that snapshot photographs of animals and men while running, jumping, and walking would greatly aid artists in transferring to their canvases the exact positions of the figures they wished to paint. In 1872 the people of California were considerably excited over the feat of Governor Leland Stanford's trotting horse Occident, which was the first racer west of the Rocky Mountains to make a mile in two minutes and twenty seconds, and the Governor was having him photographed on every occasion.
Governor Stanford also wagered that at one time during the trotter's stride all four feet were off the ground. Muybridge suggested his plan for photographing the animal's every movement, while running, trotting or walking, as a means of settling the bet, and the Governor, very much pleased, gave him free access to the stables and race course.
The photographer built a studio at the course and systematically went to work. First, he built a high fence along the track and had it painted white. Then he securely mounted twenty-four cameras side by side along the opposite side of the course and stretched thin silk threads from the shutter of each camera across the track about the height of the horse's knees. Occident was then led out and ridden along the course so that he would pass between the white background and twenty-four cameras. As he came to each silk thread his legs broke it and opened the shutter of the camera to which it was attached. Thus the animal photographed himself twenty-four times as he passed over the track and showed that Governor Stanford's contention regarding his movements was correct.
Laid in consecutive order in which the photographs were taken, each picture showed a different stage of the horse's movements, and if the series of photographs was held together and riffled over the thumb, so that each one would be visible for just the fraction of a second, the impression received, thanks to the persistence of vision, was that of a horse in motion. When Muybridge went to Paris the year after taking the photographs of Governor Stanford's horse he received a warm welcome from some of the greatest French painters of the day. He gave several exhibits of his photographs, but carried the work no farther.
Almost one hundred years before this, several brilliant Frenchmen were groping in the darkness for some way of showing motion by means of pictures, and brought forth a device known as the "Wheel of Life," or the Zoetrope. It was simply an enclosed cylinder, and upon the inner lower face, which was free to rotate, were placed a series of pictures showing the stages of some simple animation, in sequence, such as two children seesawing, or a child swinging. The upper surface was pierced with long, narrow slits, and when one looked through the slits, and the lower surface with the pictures on it was rotated, one actually saw only one picture at a time, but as they passed before the eyes the appearance was of motion. Various improvements on this idea were made, and silhouette paintings even were thrown on a screen so as to give an illusion of motion.
The development of photography was necessary, however, before motion pictures ever could be a success. About the time Muybridge took his pictures the old wet plate was superseded by the dry plate we know to-day, and scientists began the search for some material from which they could make film base.
Before the invention of films, motion pictures, as they were known at that time, were used chiefly by scientists in trying to analyze motion which cannot be traced by the human eye. Among the leaders in this work was the French scientist Dr. E. J. Marey, who studied the flight of birds and the movements of animals and men so carefully that he wrote a book entitled "Movement," which is still used by authorities in scientific research.
Doctor Marey set up another camera at the Physiological Station in Paris with which he and his associates made pictures of great scientific value. Those were the days of the early experiment with flying machines, as will be remembered from Chapter II, and the French inventors made careful studies of Marey's pictures of bird flight.
Doctor Marey's stationary camera was a simple bellows type which took an exceptionally wide plate. The shutter, which was operated by a crank, was a disk with slits in it, so that as it turned it intermittently admitted and shut off the light. Thus, as a white-clothed figure passed a dead-black background, in front of the camera, the various stages of its movements in the course of its trip from one side of the camera's focus to the other were faithfully recorded on the plate, each slit making an exposure of the image on a different section of the plate, showing the figure in a different position.
Many machines that were merely developments of the old zoetrope were brought out both in the United States and Europe, but the greatest obstacle to their success was that they were peep-hole machines of the kind that flourished in penny arcades a few years ago, rather than devices for throwing pictures on a screen so that a large number of persons could see at the same time. In general, these old-fashioned "moving-picture" machines were simply cabinets in which were mounted a series of transparencies made from pictures representing the stages of some simple animation. An electric light illuminated the transparencies and they were rotated so that one picture at a time was seen. In some of the more improved "wheels of life," such as were shown in this country, the transparencies in consecutive order were mounted on a hub like the spokes of a wheel and were rotated so that one was seen at a time, very much like the way Muybridge riffled his horse pictures over his thumb.
All this time two American inventors had been at work on the two most perplexing problems in animated photography at that time, and it was through their achievements that the first practical motion-picture machine was given to the world, just as it was through the achievements of the Wright brothers that the first practical aeroplane was given to the world.
These two men were Thomas A. Edison and George Eastman.
Mr. Edison had been working for several years on a motion-picture machine, but was handicapped by the lack of a practical film.
Mr. Eastman, after years of experiment, produced the film that made cinematography possible, in 1889.
With a strong transparent film, flexible, and compressible, to take the place of the clumsy glass plate, Edison was ready to go ahead with his work, started years before, and in 1893 the crowds at the World's Fair in Chicago saw the first motion-picture machine. It was called a Kinetoscope.
Courtesy of Thomas A. Edison, Inc.
THE CORSICAN BROTHERS—A FAMOUS TRICK FILM
The parts of the twin brothers in this film were acted by the same man, the illusion being accomplished by the double exposure trick.
Courtesy of the Vitagraph Company of America
THE GUILLOTINE
Famous scene from the photoplay based on Dickens's great novel, "A Tale of Two Cities."
Simple as it was, thousands and thousands dropped nickels into a slot and peeped into the hole at the "moving pictures." Some of the boys who read this may remember machines like it. The mechanism was in a cabinet in which the pictures were shown on a positive film. This was about forty feet long and was strung backward and forward inside the cabinet on a series of spools in a continuous chain. The film passed before the peep-hole and the pictures were magnified by a lens. They were illuminated by an electric lamp behind them. A rotating shutter cut off the light intermittently, so that each picture was seen for the fraction of a second, and then a period of darkness ensued. The shutter was the only attempt at intermittent revealing of the pictures, for the film travelled continuously.
The camera that Edison invented for taking the pictures shown in his kinetoscope was in principle about the same as the one described earlier in this chapter, except that it has been wonderfully improved in mechanical accuracy and photographic clearness. The hardest problem facing him was the machine which would show the pictures to a large number of spectators at the same time and do away with the old peep-hole machine. The idea of the magic lantern immediately presented itself, but the inventor quickly saw the necessity of an intermittent motion, for if the ribbon of pictures was drawn before the beam of light fast enough to give the illusion of motion, each picture was thrown on the screen for such a short time that it was too faint to be seen easily. From this it was to Edison but a step to a practicable projector, and nothing remained but to improve its mechanical working.
Getting motion pictures is the adventurous part of the business, for this work requires operators and actors who are athletes and who do not know the meaning of fear. As pictures of scenery and events are taken in every corner of the world—in the jungles, in the arctic ice, on mountains and in deserts, the photographers all can tell absorbing stories of the strange places and things they have filmed.
In the rough the films are divided into four great general classes, with several special classes besides. They are scenic, industrial (showing the working of some great industry like steel making), topical, and dramatic. Scenic and industrial films are simply taken at an opportune time, as it is usually not necessary to make any advance arrangements, though the photographing may incur great risks.
Topical films, such as the pictures of the recent Durbar in India or some other great current event, are very valuable when quickly sent broadcast. Of course the photographer must have the same news instinct that the reporter has to get good topical films, for he must get there first and deliver his picture "story" to his studio "editors" as quickly as possible. The photographers often have hair-raising adventures in taking such films, as the single instance of the man who went up Mount Vesuvius during an eruption and took a cinematograph film of it will show.
The greatest variety of experiences, however, is to be found in the making of dramatic films—that is, motion-picture plays. As every boy knows, these stories have just as wide a range as the books in a library. There are plays based on biblical stories, and plays dealing with Wild West adventures; there are farces, comedies, and tragedies; in fact, there is no limit to the variety. These plays, however, can be divided roughly into two classes—that is, those that are produced on the motion-picture studio stage and those produced out of doors with the natural surroundings as the stage. The interesting things about either kind would fill a book the size of this.
In the early days of cinematography only simple shows were attempted, but now nothing is too big or too complicated or too expensive for the big concerns making pictures in the United States and Europe. The first motion-picture studio here was simply a portable, glass roofed, black walled shed set on a pivot in Edison's yard in Orange, N. J. It was called the Black Maria and makes an interesting contrast to the great glass studio at Bronx Park, N. Y., costing $100,000, in which many of the Edison films are now made. All well-equipped motion-picture studios these days are fitted out with space for several stages; a great tank for water scenes, carpenter shops, scene-painting studios, furniture and other stage properties to furnish scenes, costumes, stage fittings, and a great corps of photographers, mechanics, electricians, etc., besides the company of well-paid actors who take part in the shows.
If a play is to be reproduced in the studio, the architect draws the plans for the scenery, which are sent to the stage carpenters, who make the framework and stretch the canvas. The blank scenery is then sent to the racks, where the scene painters get to work on it.
In the meantime the property man at the studio, just like the property man at a theatre, has received a list of the things he will need to furnish the scene and give the actors the paraphernalia necessary for the carrying out of the play. He ransacks his storeroom and brings out tables, chairs, pictures, etc. The studio costumer also checks off her list and sees that she has in her great wardrobe costumes to dress the characters for their parts.
Meantime the stock company of actors is called together, the scenario, or plan of the play, is read, and rehearsals begin. All this part of it and the rehearsing are very much like the work preliminary to the staging of a regular play, except that the scenes are arranged, not according to the size of the stage, but according to the focus of the camera. Each scene is timed to the second so that the pantomime will tell the story but not tire the spectators with useless repetition. In rehearsing, the actors sometimes speak their lines—that is, the words the character would say—just as if they were to be heard, because it often helps them to give the proper effect.
Finally, when the stage director has one scene of a play down fine, after perhaps days or weeks of rehearsing, the photographer is called. He consults with the stage manager, measures off the distance for his focus, so that he will get all that is necessary into the picture, and nothing that is not wanted; and after seeing that every detail is attended to, the great battery of arc lights overhead is turned on, and the stage manager says, "GO!"
The photographer begins to turn his crank, keeping one eye on the stage and the other on his stop watch, and the stage director counts off the seconds, meanwhile shouting instruction to the actors on the stage. To an outsider the noises sound like a riot or a street fair rather than a theatrical performance timed to the fraction of a second in which the movement of an eye counts in the final effect. While the camera clicks off sixteen instantaneous snapshots to the second the stage director calls out the seconds, "One, two, three. One, two, three. Look out there, don't get out of focus! Keep toward the centre of the stage. Now, Jim, run in and grab the book agent—hurry, look angry! One, two, three. That's fine! Hey, there! shake your fist." And so it goes, until the director rings a bell or shouts, "That's all!" and the scene is ended. Just as the last pictures are being run off, a stage hand rushes into the scene and holds up a large placard with a big number on it. This number is the number of the scene in the play, and is watched by the men and women in the assembling room when they gather the various scenes of a picture play together and join them up in the proper order for one continuous roll. Of course in the joining the number is cut out of the picture for projection.
It very often happens that a stage director in his effort to get a graphic story reproduced on the film takes a great many more pictures than can be crowded within the limits set for the play. Then with the scenario in front of him, and a good magnifying glass to bring out the detail of the pictures, he takes his scissors, just as the editor takes his blue pencil, and begins cutting from the story the unnecessary pictures, just as the newspaper or magazine editor cuts useless paragraphs from the story or article. He must not cut out any picture that helps to tell the story, and yet he must sometimes cut out as much as 400 feet of film. He "kills" an unnecessary picture here, and an unnecessary picture there, and adds up their length until the story has been reduced to the proper size.
Although spectacles such as the one in the picture representing a battle on a bridge, and others even larger, are staged in the various big motion-picture studios, the most exciting work in the filming of motion-picture plays is out of doors where the natural surroundings make the stage. A great many of the shows seen to-day are taken this way, with real trees, real water, real mountains, or real streets affording the settings. Hence with studios in which battle scenes, riot scenes, water scenes, and practically any indoor scene can be reproduced; and also the great outdoors at the disposal of the cinematographer, there is practically no limit to the subjects that can be turned into dramatic films for the education and amusement of the public.
A few instances of the plays made out of doors will serve to show the limits to which the producers are willing to go to get new shows. The Edison company, with its big studio in New York and its manufacturing plant at West Orange, N. J., in the heart of the country where the Revolutionary War was fought, is reproducing a whole series of films of American history. These, so far as possible, are made on the exact spots where the dramatic events occurred. The first of the series entitled, "The Minute Men," was taken near Boston, where those historic defenders of liberty fought for their country. In this film is the famous scene representing the Battle of Concord, which was taken on practically the identical ground where the battle was fought. The producers spent a great deal of time in planning this series of pictures and so far as possible had every historical fact correct, so that the value of the series from the educational point of view is apparent. The other titles in the series will show how the scenes of the Revolutionary War were brought home to the American people. They included "The Capture of Fort Ticonderoga," "The Battle of Bunker Hill," "The Declaration of Independence," "The Death of Nathan Hale," "How Washington Crossed the Delaware," "Church and Country; an Episode of the Winter at Valley Forge," and so on. The film dealing with Washington's trip across the Delaware in the ice was made under conditions as nearly like those of the actual events as possible to get them. The pictures were taken during the coldest part of last winter (1912), and the photograph opposite page [193] was taken while the big scene was being acted out. This was taken in an arm of Pelham Bay, near New York, and the "scene shifters" had to work for hours in the bitter cold breaking up the ice and shifting around the great cakes in order to get the desired effect. Their success is attested by the picture reproduced here.
The Selig Company, with studios in Chicago and Los Angeles, and big stock companies of actors in both places also take some wonderful outdoor films. One of these was a play representing life in the African jungle, for which a special trainload of actors, and a whole menagerie of elephants, camels, lions, rhinos, leopards, pumas, zebras, and other animals, were shipped to Florida, where scenes much like those in Africa were found. This same company also sent a stock company and a corps of photographers to the Far North, where a film play was made amid the Arctic ice.
The Chicago studio of this concern is one of the wonders of cinematography, for not only has it a great building in which indoor plays are filmed, but a great land reserve for outdoor productions. In one place are artificial hills built in the natural forest, and upon them artificial feudal castles. In another are log cabins for frontier scenes, and in yet another a barren stretch for other kinds of scenes. The Los Angeles company is close to the mountains, the ocean, and the Great American Desert, so that it can furnish material for an endless amount of exciting Wild West shows.
One of the big films made in Europe was "The Fall of Troy," produced by the Itala Film Company, which reproduced the great wooden horse, the walls of Troy, and all other historical details. The great French, German, and English companies also have made big films.
In the production of plays built on well-known novels the motion-picture industry has found one of its most successful fields. Dickens's great novel, "A Tale of Two Cities," afforded the Vitagraph Company of America, one of its best films, while James Fennimore Cooper, Alexander Dumas, and even Shakespeare, and grand opera have been transferred to the cinematograph. From the great Biblical stories also have been taken films that have been shown by missionaries, and others interested in religious work, all over the world. The "Passion Play" was one of the first long films ever shown and it made a tremendous success.
Big spectacles are always popular and to fulfill the demand two locomotives have been run together at high speed, the motion-picture concern buying the machines outright for the purpose and leasing the railroad for a day; an automobile has been driven over the Palisades of the Hudson River, ships have been towed out into the ocean and blown up and whole towns of flimsy stage construction have been built only to be burned, while the motion-picture photographer recorded the whole thing on a film. One concern even got permission from the Los Angeles Fire department during a big fire, and dressing an actor as a fireman cinematographed him as he heroically rushed up a ladder amidst the flames and rescued a screaming woman from an upper window. The woman was an actress who had risked her life to go into the burning building and be rescued.
Of course the great motion-picture industry has not been without its fatal accidents. Several times actors playing the parts of men in difficulty in the water have actually been seized with cramps and have drowned before the eyes of the spectators. One time a picture was being taken of a band of train wreckers who were supposed to tie the switchman to the track. The train was supposed to stop just short of the man, but it actually ran over and killed him. The pictures were used at the inquest. During the filming of war pictures there have been explosions of gunpowder that were not intended, and in the taking of pictures of wild animals in their native haunts and in menageries, several photographers have been badly injured.
There is another big and important department in the filming of motion picture plays in trick photography. Every one who reads this has seen at the picture-theatre films of things that he knows perfectly well never could have happened—men walking on the ceiling, fairies the size of a match acting on a table beside a man, a saw going through a board, a piece of furniture assembling itself, a man run over by an automobile, his legs cut off, and then stuck on again all within a few minutes, marvellous railroad wrecks, and a thousand other things which could not happen or which the motion-picture photographer probably never could catch in his lens. All of these things are done through trick photography.
Double exposure, double printing, and the stop motion are the most common methods of obtaining these marvellous results. Opposite page [200] is a picture obtained during the reproduction by the Edison Company of Alexander Dumas's novel, "The Corsican Brothers." This film was obtained completely by the double exposure. In the story, the two brothers are twins so much alike that they cannot be told apart. They act exactly alike, and one even feels what, the other feels. In making the film the producers decided that it would be impossible to get two actors that looked enough alike to take the parts of the two brothers, so the same man acted both parts. In the picture referred to the brothers sitting at table with their mother are one and the same actor.
The picture was made by blocking off the whole left half side of the film with black paper and running it through the camera while the actor played the part of the brother on the right side of the table. He was timed to the fraction of a second, and when the exposed half of the film was blocked off with paper and the unexposed half run through, he acted out his part on the left side of the table, to this time schedule. So exact was his work that when the brother on one side of the table spilled a drop of hot coffee on his hand and started in pain, the brother on the other side, feeling the same pain as his counterpart, jumped at exactly the same second.
Another popular trick with the double exposure is a scene showing mermaids or divers swimming or walking at the bottom of the sea. First a large brilliantly lighted glass tank is set up in the studio, stocked with fish and sea life, and photographed. In this kind of a film the images of the real water are a little under exposed. Next a space the size of the tank is measured off on the floor with a gray scene laid flat. On the scene are painted faint lines to indicate water, and faint outlines of fish, seaweed, etc. Then the actress dressed for the part of a mermaid lies flat on the setting and goes through the graceful motions of swimming while the film upon which the real water pictures were taken, is run through the camera, which is placed above her with the lens pointing directly downward.
Another example of double exposure is seen in most films where Lilliputians or small fairies enter into the picture. The parts of both full-grown human beings and diminutive fairies are played alike by adult actors, but the difference in their size is obtained by taking each on the same film at different times. For instance, suppose a tiny fairy is supposed to appear to a grown man in the picture play. First the man goes through his act with the camera photographing him from a distance of about fifteen feet. Next the fairy goes through her act, bowing, etc., to the place where the man stood and is photographed on the film from a distance of say one hundred and fifty feet. The two impressions when printed give a lifelike effect of a full-grown man and a tiny sprite.
There are numberless films made by the stop-motion system, which simply means that the stage hands rush in and arrange things while the shutter is closed. All pictures in which you see a man or a woman falling off a roof or out of a window and subsequently getting up and running away are made by this system. The Edison film showing an automobile going over the Palisades and the driver being hurled to the rocks below was done with the stop motion. It is very simple. The cinematographer photographed the approach of the automobile and the human driver in the seat approaching the cliff at terrific speed. He stopped his camera, the automobile came to a stop, the automobilist got out and a dummy was placed in his seat. Then by starting the automobile a little back of where it was slowed down and stopped, and photographing, it the public could not tell that it had been stopped, and that the man in the seat who was hurled to the rocks below with the machine was a dummy.
A development of this is the picture-a-turn motion, which simply means that with each turn of the crank of the camera one exposure is made. By this trick many of the strangest films seen are made possible. The magic carpenter shop where saws and hammers move without human aid is an example. It is simply done by stage hands who rush on to the stage between each turn of the camera and advance the tools to one more stage of progress. The saw is at the top of the board, and the hammer is suspended in air (by invisible wires), etc. In the next picture, the saw is in different position, and the hammer has descended to the head of a nail. In this way all the magical effects of inanimate objects taking on life in the film are accomplished. One of the interesting details is the appearance of such objects as boards rising from the floor and placing themselves upon the bench ready for the saw. To do this the operator, keeping his shutter closed, advances his film a couple of feet and takes a picture of the board falling to the floor from the bench (pulled off by an invisible wire). As the film is moving backward, the picture when exhibited in sequence shows the board not falling but rising from the floor, and placing itself on the bench in a most mysterious manner.
Moving the film backward will give many strange results. For instance, in the plays where a little child is snatched from death under the wheels of an onrushing train just as the cow-catcher is upon her, it is no longer necessary to risk human lives before trains. First, the onrushing train is photographed with the film moving forward right up to the point where the child is to be standing when rescued. Then the train is allowed to run on past the point. It is then backed up at high speed, and the film run backward. When the locomotive rushes past the spot where the child is to be rescued her heroic rescuer simply dashes on to the tracks amid the dust of the receding train and places the child between the rails. When this section of film, which is taken backward, is fitted into the rest of the ribbon, and is run through the projector forward, it looks as if the rescuer rushed on to the track and grabbed the child out of the way as the train passed by.
Another popular trick by which fairies or ghosts are made to appear gradually in motion-picture scenes is the one by which the lens is narrowed down or opened up gradually. If a ghost is to appear, the hole through which the light strikes the lens is narrowed down so that only the brightest objects are photographed. The hole is gradually enlarged so that the light increases and brings out the figures plainer and plainer, until the ghost is in full view.
A great many good films, such as railroad wrecks, automobile journeys through the clouds, etc., are made with models, propelled by invisible strings over skilfully built scenery. The scene of figures walking on the ceiling is very simple inasmuch as it is only necessary to set the floor of the stage to represent a ceiling and take the pictures with the camera upside down. Men and animals can be made to run up the sides of buildings, simply by laying the scenery on the studio floor, and photographing the whole thing from above.
A ROMANCE OF THE ICE FIELDS
This film was taken in the dead of winter, and the man is in a dangerous position on a real ice cake.
THE SPANISH CAVALIER
A whole motion-picture outfit was taken to Bermuda to get this photoplay.
ALL READY FOR A THERMIT WELD
After the little hole at the bottom of the weld, through which the redhot shaft inside shows, is plugged up, the thermit is ignited.
Of the recent developments in cinematography the ones we hear most about are colour pictures and talking pictures. So far, these two points which would give the last touch of realism to the scenes thrown on the screen are in a very imperfect state of development, but it is safe to say that it will not be very many years before we will have them duplicating what we see and hear in actual life just as faithfully as the black and white pictures now duplicate motion.
Science so far has not given us a method of actually taking a motion-picture negative in the natural colours, such as now can be taken in still photography, so at first the pictures were coloured by hand, and later by stencils. This is a difficult and a tedious undertaking, however, and newer methods have been introduced.
Although there are several systems being worked out the one best known is the Kinemacolour, which achieved its greatest fame by showing the pictures of the coronation of King George in England, and the Durbar in India in colours. The Kinemacolour system is simply one of photographing and projecting through screens of red and green. The shutter of the camera is made up of four parts, as follows: a transparent red screen, an opaque space, a transparent green screen, and another opaque space. Thus, by the law of colours laid down by science, when one picture is photographed through a red screen, all the different tones but red are arrested by the screen, and only the objects having shades of red are photographed. Next, when the green screen exposes the next space of three quarters of an inch, only the objects having green tints are photographed, as all other tints are arrested by the green screen.
The film itself shows no colour other than black and white, but when it is projected through a shutter that works exactly the same as the camera shutter the pictures show the objects in their natural colours. That is, the alternating pictures taken through the red screen and shown through a screen of the same colour show all the tones of red, while the alternating pictures taken through the green screen and likewise projected through a green screen show all the tones in which appear green. Thus, with the aid of the persistence of vision and a somewhat faster system of photographing and projecting, the tones blend and we see on the screen at the same instant red-coated soldiers marching past beautiful green trees, and so on. In order to make this possible it is necessary to give the films a treatment in a solution that makes them more sensitive to all light than they would be for ordinary cinematography.
The drawback to the system, as you will have noticed if you have seen these pictures, is that red and green do not make up all the primary colours of light. In the direct rays of light (not reflected light as from a painted wall) the primary colours, from which all the other tones are obtained, are red, green, and violet, but it has been found a little too difficult a mechanical process to use the three screens instead of only two.
The hardest job of the inventors of talking pictures was to work out a mechanical device that would make a good phonograph and a motion-picture projector keep step, so that, for instance, the actor would not be heard singing after the pictures had shown him close his mouth and leave the stage. Ever since his invention of the Kinetoscope, Edison has had this very thing in mind, and has prophesied that in the near future grand opera with motion pictures and phonographs will be within the means of every patron of the motion-picture theatre. Edison's idea for obtaining this is to make the phonographic and the cinematographic records at the same time in order to insure perfect accuracy of sound and appearance, and his experiments are meeting with success.
A fairly successful device for giving the phonograph and the projector synchronism, or, in other words, keeping them in step, has been worked out by the Gaumont firm of Paris. The phonograph and the projector are run by two motors of exactly the same size and power, from the same wires. The armatures of the motors are divided into an equal number of sections, and each section of one is connected with the corresponding section in the armature of the other, so that one cannot rotate for the fraction of a second unless the other rotates with it. A little switch working on another motor, which works on a set of gears, will speed up or slacken down the talking machine so that if the armatures get "out of step" one can be speeded up or slowed down so that the figures in the pictures will appear to be talking, laughing, or singing, just as they do in real life.
Another of the recent developments in cinematography is the di-optic system which aims to show every stage of the motion of figures, instead of the stage of motion every sixteenth of a second, as is in the case with the usual apparatus. The di-optic camera is simply two machines set side by side in one. It takes two loads of film, has two film gates, and two lenses, but works by turning one crank. The single shutter revolves in front of the twin lens, so that when one side is exposing a length of film the other is closed and the film is advancing. The two rolls of negative exposed in this way record the complete motions of the figures before the camera. The projector also is a di-optic machine working in the same manner as the double-eyed camera, so that when the pictures are thrown on the screen they are seen practically constantly, instead of every sixteenth of a second, for while one is hidden by the shutter, another is thrown on the screen. Also inventors are working on a scheme for taking motion pictures on glass plates instead of on films.
As was mentioned previously the use of the motion-picture machine has been very valuable to science, and by adapting the cinematograph to a powerful microscope a great many motion pictures of the life of bacteria have been obtained. Also motion pictures are sometimes made of surgical operations. Carrying this work even farther still, animated photography and X-ray photography have been joined so that science now can make motion pictures of the processes that go on inside small animals.
Owing to difficulties not yet overcome moving X-ray pictures cannot be taken of the human body at this time. Röntgen rays cannot be refracted, or collected in a lens. Hence the film for an X-ray picture must be equal in size to the picture desired. It is impossible to increase the size of cinematograph films with much success because of the danger of breaking or tearing them when under the strain of the rapid course they must pursue through camera and projector. These facts made it necessary for the scientists experimenting with X-ray motion pictures to photograph only animals, but they were greatly encouraged because they obtained some excellent views of the digestive processes of mice, guinea-pigs, fowls, and other small animals. The bones of the human hand also were photographed while the hand was opened and closed.
M. J. Garvallo, who carried on a great many interesting experiments in France with this type of motion pictures, used a somewhat larger and more sensitive film than the standard, combined with an apparatus too complex for attention here. This phase of cinematography, however, is still in its infancy and we can look for great improvements at an early date.
Another Frenchman, Prof. Lucien Bull, who was one of Doctor Marey's assistants in the early stages of cinematography, has made pictures of the movement of the wings of various insects such as flies, bees, wasps, etc. To do this he has had to make the fastest known cinematograph. It was an especially constructed apparatus entirely unlike the ones described here, but through the agency of an electrical spark which illuminated the vicinity in which the insect flew, 2,000 pictures per second were taken, instead of the usual sixteen.
The very antithesis of the scientific are the uses of the motion-picture film as an illustrated magazine or newspaper. There are only a few successful "animated newspapers" in the world, but the idea will probably spread. The staff of such a publication is made up of photographers, who are scattered about in every nation on the globe. There are regular offices in all the big cities which are ready at a moment's notice to send photographers to any part of their territory. These photographers get films of all the important news occurrences of the day, parades, street demonstrations, wrecks, fires and whatever else fills the newspapers you read every day. The films are hurried to the main office where they are developed, cut down to short "items," or allowed to run as long, "stories" just like in a regular newspaper, pasted together with suitable headlines, printed in one continuous roll of about 1,000 feet and rushed out to the subscribers, who are usually theatres with audiences eager for the "paper."
Such are a few of the many motion-picture activities which have sprung up in the last few years, and made it possible for us to see whatever is interesting in any part of the world, on the cinematograph screen. Beside the professional cinematographers, there are of course any number of smart boys and young men who are having fine times with the amateur projecting outfits sold by the big makers of apparatus. These machines run from mere toys made up for a little roll of film, already prepared, to projectors with which very creditable parlour shows can be given.
CHAPTER VII
STEEL BOILED LIKE WATER AND CUT
LIKE PAPER
OUR BOY FRIEND SEES HOW SCIENCE HAS TURNED THE GREATEST KNOWN HEATS TO THE EVERYDAY USE OF MANKIND
"HOW hot is it in that furnace?" asked the scientist's young friend as he poked about the laboratory one day.
"That is not very hot now, but we could increase the temperature to about 4,000 degrees Fahrenheit if we tried hard enough," answered the man who, outside of his work, enjoyed best of all the visits of the boy. "But the heat of the laboratory furnace most of the time is nothing compared to the heat that we can put to practical use through a couple of new inventions I have been trying here."
"What are they for?" asked the boy, immediately all interest, for he was a member of the metalworking class in his school, and was constantly on the lookout for better ways of working in iron, steel, copper, and brass.
THERMIT IN ERUPTION
With a blinding, dazzling glare and a gentle hissing the thermit in a white-hot molten mass fills the mould and runs down the sides like volcanic lava.
DR. HANS GOLDSCHMIDT
The inventor of Thermit.
"Well, they both are used in welding metals and in one—the thermit process—the hardest steel can be reduced to a molten mass of white hot metal boiling like a tea kettle on a stove, in about a half a minute. You see that requires a great deal of heat," continued the chemist, "and in fact the temperature is 5,400 degrees, Fahrenheit.
"The other process that I have been trying is known as autogenous welding, and in this even a greater temperature is generated than by the thermit process. In the tiny flame no bigger than the point of this pencil that comes from the autogenous welding torch the temperature is about 6,000 degrees Fahrenheit."
"My!" said the boy, "how could any one ever measure such a heat as that?"
"Science teaches us how to do that just as science taught us how to produce these great heats. Why, you know, in the electrical furnaces at Niagara Falls they produce a heat that they think reaches the 10,000 degrees of the sun. Outside of that, however, the thermit process and the autogenous welding process attain the greatest known heats."
"Those must be fine," said the boy, "because before our schools began to teach metal working, I used to play blacksmith and heat pieces of iron in the fire, but I could never do anything with it, and now that we are learning welding in the blacksmith shop at school I see what a hard job it is. I wish we could use these processes at school."
"Well, you will be able to use them some day," said the scientist, "but it took science a long time to find out how to produce and use very high temperatures.
"In the stone age, thousands and thousands of years ago, when men lived in caves and ate raw the animals that they caught with their hands, fire was first discovered by an accident. There are many legends of how the hairy savages that populated the earth fell down and worshipped the aboriginal scientist who taught them how to warm their caves.
"Soon, however, fire became a necessity of life to mankind, for it was discovered that meat tasted better when exposed to a flame—that, is, when it was cooked—than when it was raw. That was a big step toward civilization, but it was a bigger one when some wild mountain tribe found that they could make much more deadly weapons than the rude ones they chipped from flint, by melting down a certain kind of rock and fashioning it into spear heads, arrow heads, and hatchets. From that time on the development of the art of metal working took only a few thousand years, until to-day man's great knowledge of metalurgy has enabled him to make such tremendous fighting machines that war is becoming entirely too destructive, and too expensive a thing to rush into lightly. Thus, heat and metal working are helping to force the world forward to another step in civilization—universal peace.
"After learning how to make these hardest of metals, man has now solved the problem of making them boil like water with the thermit process and of cutting them like paper with the oxy-acetylene gas torch, all in less than a minute.
"You see this bag of coarse black powder that looks like iron filings? Well, it is the thermit. Put it into a crucible, set off a pinch of ignition powder on the top, and the whole thing will ignite in half a minute, throwing off a blinding white light and thousands of sparks like beautiful fire works. That is the thermit reaction.
"You know more about the oxy-acetylene gas torch, for in your metal working at school you used the gas blowpipe to make a very hot flame. The oxy-acetylene gas torch is just a high development of this, for instead of ordinary gas, acetylene is used and instead of air we use pure oxygen."
The caller sat down and asked his friend to tell something more about these two marvelous inventions. The story was several days in the telling, for there were visits to foundries and experiments in the laboratory, besides many long talks.
"First we will see about thermit," said the man, and began to talk as he worked over a crucible.