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Sales. David Sarnoff, 37, vice president & general manager of R. C. A., is in the position of a man who has something that customers clamor to buy but which he knows is not perfect enough to sell under his name. "In five years," said he, "television will be an art and an industry. But I cannot promise any date at which we can make the sale of television receiving sets. Generally there remains considerable testing & experimenting to be done."
Receiving Set. The television receiving set contains practically the same elements as the sending set, plus an all-important invention—a Moore tube. This tube is similar to a radio vacuum tube but filled with neon gas which glows pinkly when current passes through the tube. Light in the tube can vary in intensity 1,000,000 times a second. As in ordinary radio receivers the waves coming into the television receiver are amplified. Then instead of being shunted through only a loud speaker, they are passed through both a loud speaker and the Moore neon tube. The loud speaker changes part of the incoming waves into sound, the tube another part into light. That light, flickering too fast for analysis by the unaided eye, shines against a disc like the disc in the laboratory—with 48 holes arranged spirally and rotating 18 times a second. The swiftly turning holes interrupt the tube flickers just enough for the human eye to receive visual impressions. Observers see pinkishly as well as hear loudly just what is happening at the sending station.
De Forest Doubts. Said Dr. Lee De Forest, inventor of the three-element vacuum tube: "I do not think that any marked advance has been made in the Alexanderson television apparatus, except in the synchronization system. I think that television will never be practical in the home, due to the fact that the present methods require large rotating parts operated by a motor. The difficulty is that the operator at the receiving end must constantly regulate a little knob or dial, to prevent the picture from becoming distorted. We are still a million miles away from the application of television on a large theatre screen, because eighteen inches today constitutes approximately the largest television screen in use. A new system must be developed, based on another branch of physics, which will get away from heavy and rotating parts before seeing by radio can be made practical for private use."