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.