Journal of the Society of Motion Picture Engineers (1930-1949)

704 ABSTRACTS [J. S. M. p. E. Running the Talkies. XVII. R. H. CRICKS. Kinemat. Weekly, 154, Dec. 5, 1929, p. 63. A new film and disk sound reproducing system has been invented by A. W. Harris and marketed by the British Phototone Company. Special features are discussed, such as the novel form of the synchronizer. Instead of the usual sound gate, there is a drum around which the film passes on its way from the bottom sprocket to the spool box. The drum being mounted separately from the projector, the effect of vibration of the latter is eliminated. A radiovisor bridge selenium cell is used in place of the usual photo-electric cell. — Kodak Abstr. Bull. Corophone. New Talkie Apparatus. Kinemat. Weekly, 154, Dec. 12, 1929, p. 61. Brief notes on the Corophone reproduction equipment for sound-on-film or disk are given. The sound-on-film leads can be fitted to practically all projectors. For the illumination of the light-sensitive cell, a dual light source is provided which is run from a battery. No other batteries are employed. — Kodak Abstr. Bull. Running the Talkies. XVIII. British Acoustic. R. H. CRICKS. Kinemat. Weekly, 154, Dec. 12, 1929, p. 61. The new form of the British Acoustic reproduction equipment is described and criticized. The optical system is unique in that instead of the usual narrow slit, 0.002 inch in width, there is an aperture about Vs inch square. The rays from the exciting lamp are focused on this, and a second lens focuses the image of the sound track on a selenium cell. It is suggested that the range of tone of the latter is not quite equal to that of a photo-electric cell. It is capable, however, of a current emission about ten times as great as the photoelectric cell. The price of the outfit is approximately 5500 dollars. — Kodak Abstr. Bull. Unbreakable Movie Film. Sci. Amer., April, 1930, p. 299. A regular 16 mm. film is cut in strips 43/4 inches long. Every strip is then sealed between two pieces of thin steel through which an aperture for each frame has been punched and along the edges of which are a number of holes that are equivalent to the sprocket holes in the film. Each film section is equal in length to 16 frames. The projector consists of a magazine in which the strips are stacked, an electro-magnet to draw the top section, claws to move intermittently past the aperture, and a take-up magazine. As each frame stops in the aperture a 100 watt lamp projects the image onto a mirror placed above the aperture, which mirror deflects the beam of light along a horizontal axis onto a translucent screen. The strips fall by gravity in the take-up magazine from which a conveyor chain transfers them to the bottom of the feed magazine. Test runs exceeding 15,000 passages through the system have shown no wear whatever upon the film. G. L. C. Analysis of Camera Silencing Devices. Projection Eng., March, 1930, p. 13. The article describes the tests made by a committee of the Academy of Motion Picture Arts and Sciences. It is recommended that the motor be mounted as an integral part of the camera so that any external silencing device will be effective for both. The type of tripod used does not seem to have much effect on the noise. The amount of noise transmitted through the silencing device appeared to be nearly independent of the direction of the pick-up device from the camera. A table gives a comparison of various silencing equipments. The first column gives a brief description of the nature of the silencing equipment. Column 2 shows how much louder the noise of the uncovered camera was than average whispering. The next column shows the sound insulating ability in db. of the various devices