Page:Popular Science Monthly Volume 90.djvu/449

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Motion-Pictures on Glass

��G. Bettini, the distinguished inventor, substitutes glass plates for celluloid film and thus gives the motion -picture industry a new turn

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��� ��The glass plate substitute for celluloid film. The images are each one quarter of an inch square, and there are five hundred and seventy-six images on each plate. One glass plate is equivalent to about seventy-five feet of standard film. At the right is Mr. Bettini and his projector, with the plate in position for showing motion-pictures

��WHEN a cheap, durable, non-inflam- mable substitute for the ordinary motion-picture celluloid film is found, we may expect to see motion- picture machines enter our homes and take a place beside the phonograph. So long as the cost of film is excessive, as it is at present, and so long as the film is inflammable, as it always has been and may continue to be, it will be difficult to popularize home motion-pictures.

To overcome these diffi- culties, G. Bettini, of New York, has invented several cameras and projectors in which ordinary cheap glass plates take the place of the usual expensive film. For instance, he has evolved a motion-picture camera that utilizes glass plates in place of the usual film; a motion- picture projector for the home which uses the same glass plates; a second projector which utilizes circular non-inflammable disks; a machine which



��The Bettini principle of pro- jection. The light from the lantern strikes the prism and is there bent at right angles toward the image on the plate. Passing through the plate it enters the lens to which the prism is attached, and is thrown on the screen

��prints pictures on disks from standard film subjects, and a mechanical printer which makes square glass plate positives from standard film.

The glass plates which Mr. Bettini sub- stitutes for celluloid films are the same as those used in ordinary photography, the

size being approximately

five by eight and a half inches. The images, ar- ranged in vertical and hori- zontal rows on a plate, are each one-quarter of an inch square. There are five hundred and seventy-six images to each plate, which is equal to about seventy- five feet of standard film. The developing of the nega- tive plates and the printing of the positives is as easy as in ordinary photography.

The Bettini principle of taking and projecting pic- tures is novel yet simple. The glass plate is moved downward, one row at a time, while the camera lens or the lantern lens (the lens for taking the picture



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