Practical Cinematography and Its Applications

by Frederick Arthur Ambrose Talbot

(1)

(2)

Films prepared by Professor Cranz with his Remarkable Camera.

(1) Moving-pictures of the ejection of a cartridge from an automatic pistol.

(2) Motion photographs of the splintering of a bone by a bullet.

The Cranz apparatus is somewhat more complicated than that designed by Monsieur Bull, though the fundamental principle of operation is the same. The film, resembling an endless belt, is passed round two steel cylinders, one of which is driven by an electric motor. Images of standard size are produced under the illumination of the electric spark, which concentrates the maximum amount of light upon the moving object. The photograph is in silhouette, and the disposition of the apparatus is such that five hundred consecutive pictures can be made in one-tenth of a second, the period of exposure varying between one-millionth and one-ten-millionth of a second. The outstanding feature of the installation is the special and novel type of interrupter. It consists of a pendulum by which the sparking is started before the projectile is fired and made to continue until the film has been exhausted.

Some of the results obtained by this apparatus are very remarkable. When the films are projected upon the screen at the average speed of sixteen pictures per second the flight of the bullet can be followed with ease. One film shows the effect of a bullet striking a suspended india-rubber ball filled with water, and brings out the remarkable formations the ball assumes during the infinitesimal part of a second when the bullet is passing through it. Another interesting film shows the effect of a high velocity bullet striking a bone, and the manner in which the bone is splintered and smashed by the force of the impact conveys a realistic impression of the destructive force of the modern rifle projectile. The deadliness of the automatic pistol is well known. Since seven shots may be discharged in four seconds, the movements of the mechanism are too rapid to be followed by the naked eye. Yet by means of the Cranz apparatus every motion is caught, and the whole is slowed down in projection to such a degree that the complete cycle of the firing of the shot and the expulsion of the cartridge, which normally occupies only a fraction of a second to complete, occupies about thirty seconds upon the screen. When these pictures were exhibited for the first time a number of black specks were observed to accompany the expulsion of the spent cartridge. These proved to be grains of powder which had not been ignited. Their existence had never before been suspected, and the result was curious. After minute examination of the pictures a change was effected in manufacture of the cartridge so that the waste of powder through non-ignition should be reduced to the minimum. The success achieved in this direction was shown by the absence of non-ignited grains in subsequent pictures.

Another wonderful series of moving pictures was prepared by an American ophthalmic surgeon. He embarked upon elaborate researches to gain further information about the eye and its peculiarities both in sickness and in health. The illumination of the eye was carried out very cleverly, so as to obtain the greatest possible brilliancy without causing fatigue to the subject. Accordingly his pictures were absolutely normal. In these experiments glass plates were used, for the reason that they give results much finer and more detailed than celluloid. In celluloid the grain of the base of the film is apt to be disturbing to very fine studies. In this way a great deal of new information was gained. One of the most remarkable discoveries was that the sensitiveness of the organ of sight is far greater than was previously supposed, and that the eye never is absolutely still, even when commonly regarded as being fixed and steady.

During the past two or three years the uses of the cinematograph in medicine have been much extended. A former chapter has described its application to the study of microbic life, but the latest innovation is to employ it in the operating room. The pages of the medical papers are filled with reports of curious and unusual surgical operations, but mere reports are necessarily somewhat imperfect. In view of these circumstances it occurred to one eminent surgeon that a cinematographic record would form a first-class supplement to the technical description. The initial experiment proved a complete success, and accordingly the practice has been extended. In this direction France, Germany, and the United States are taking a very active part. Films of this character can be made to serve two useful purposes. They are valuable for the transmission of practical information between medical men and are useful in the lecture room among the students. Suppose a hospital in New York has a strange and unusual case for operation. Only the students in that establishment have the opportunity of witnessing it. But by the aid of the moving-picture camera and a lecture it can be reproduced in photographic animation upon the screen for the benefit of medical graduates in the various hospitals throughout the world.