Sound motion pictures : from the laboratory to their presentation (1929)

348 SOUND MOTION PICTURES II. Television: Problems and Promise We have been discussing the probable future of the innovation. But what is television? There are three separate phases in the development. The first is semiphotographs by radio, which are now being effected every day in the course of regular business. The second is transmitting motion pictures by radio. The third is televising actual events. Until recently television has been able to show only stationary or slowmoving objects without blurring the picture. This defect, however, is being rapidly overcome. Demonstrations have been given in which images of two men boxing, fencing, and swimming came in with "fair clarity" over a band only forty kilocycles wide. Some stations have been successful in broadcasting very small pictures on a channel ten kilocycles wide in the broadcast band. One of the big problems pertaining to television is the selection of wave lengths most suitable for picture transmission. For adequate television service, channels one hundred kilocycles wide are essential. One may draw his own conclusions, therefore, concerning the commercial feasibility of the feats I have mentioned. Until recently, moreover, it was impossible to send anything but highly illuminated scenes over the radio because the photo-electric cell, which is to light waves what the microphone is to sound waves, demands intense illumination. Those who are familiar with photography realize that the photo-electric cell — the eye of the contrivance— is exposed to the scene only -s-u-.Tnro" of a second. It therefore was not possible to televise any scene in natural sunlight, or any scene with human actors except for very short flashes, because of the intensity of the light. The Bell Telephone Company, however, has devised a new system of television whereby it is possible to trans