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Show Radio Vision Era Fast Approaching Secret Cell Proves to Be Big Step Forward in Television Tele-vision Art. Television "seeing what is happening happen-ing at a distance in the .same instant hb it happens" is no longer in Its early experimental stage, according to an article in Kadio broadcast Magazine. Maga-zine. Preparation has already been made in England for the commercial production of televisors (instruments for the reception of moving pictures), And J. L. Baird, the inventor of what is likely to be a highly successful system sys-tem of television, is nightly transmitting transmit-ting his television Impulses between two points in the London area. About this man Baird, there is much to say. After the war, he went into business with a patent sock he had invented, designed to keep out the dump. Being a Scotsman, he knew well that his sock project was no idle one, for stringent measures were necessary nec-essary to keep out the eternal char-acterii.tic char-acterii.tic of his native moors. Nor was his surmise incorrect. Money was plentiful, but just as matters looked rosy for him, he was forced to retire from business on account of ill health. Throughout the days of his business life, Baird had one hobby scientific research, and to this he turned when he became inactive in business. As far back as in 1912 he had devised a scheme for television and, taking up , the threads where be had left olT, it was in a remarkably short time that lie was able to transmit shadowgraphs. shadow-graphs. That is, by Interposing an opaque object between a source of strong light and a selenium cell, he was able to transmit to the distant receiver, and reproduce on a screen, a shadowy outline of the object at the transmitting end. Shadowgraphs Not Television. So far, so good, but -shadowgraphs are not television. Baird soon found, like so many other investigators in various countries, that successful television tele-vision is a much more difficult thing. In the case of television, it is n. f enough to send mere outlines of the object to be transmitted. Not only . Hie conlour, but also all the details . ) and gradations of light and shade, together with a lifelike reproduction of all movements, must be transmitted and received. To achieve this, the arrangement ar-rangement of scene and light source must be reversed. That is to say, the light, instead of shining on the light sensitive cell, must shine on the scene, and, under these conditions, the a.nounl of light which actually reaches the ceil is that amount which is relieved re-lieved from the scene. Baird found that the amount of light retlected from the human face is of the order of one candle power only, and when the image of the face is broken up into many small parts for transiiiissioc purposes, it will readily be' realized Unit the amount of light which actually ac-tually falls on the light sensitive cell at any given moment is extremely small, indeed. Baird did not find satisfactory sat-isfactory either the photo-electric cell or the modern selenium cell for his experiments, ex-periments, and so invented u cell of his own, the secret of which is. still closely close-ly guarded. All that Is said about it in the Radio Broadcast article is that it is a cell of the cnllodial type, that is, one made up of extremely finely divided selenium in suspension in a liquid. Month after month Baird worked on bis problem, using apparatus appar-atus of the crudest description. The biscuit tins, sealing wax, string, and oilier makeshifts beloved of the true inventor, and scoffed at by the sterile pedant, were very much in evidence. At hist, however, in April. !)2."i, he had the satisfaction of giving the first public demonstration of television, transmitting outlines between two separate sep-arate machines. These outlines were not the shadowgraphs referred to above, but were transmitted by reflected reflect-ed light a most important point, showing an enormous advance over the earlier experiments. They were, however, very rough and flickering, and mere outlines. Though a few months ago Baird was able only to transmit an object the size of a human face, now he can take in a complete head and shoulders. Headers may remember that during the early days of the moving picture, the results on the. screen were far from perfect. There was a constant flicker, the focus was often wrong, "and there was always the "pouring rain" effect. The images on the screen of Bairds's televisor suffered from very similar effects, but these are rapidly being eliminated, until, at the present time, a highly creditable demonstration can be given. Perfectly Clear. The writer in Radio Broadcast, A. Dinsdule, Is able to speak authoritatively authori-tatively on this subject of progress, for he witnessed one of Baird's earliest earli-est demonstrations, and lias been in close touch with developments ever siuce. The image seen on the televisor tele-visor screen is pefectly clear and unmistakable; un-mistakable; the sitter before the transmitter can be recognized without tiie slightest difficulty, and every detail de-tail of his features can be taken in, even to blemishes of the complexion. All movements are faithfully portrayed, por-trayed, just as they would be on a "movie'' screen. Even the smoke from 'a cigarette can be seen, and its ascending as-cending wreaths followed. The results are not yet as perfect as those seen on a motion-picture screen, but such rapid progress has been made that the writer lias no doubt that before long absolute perfection will be arrived at. At present Baird is stepping out of his laboratory as far as the location of his televisor is concerned, and he is now engaged in broadcasting ids television tele-vision impulses from his laboratory in the heart of London to a receiving station sta-tion at Harrow, about nine miles distant, dis-tant, using a itfO-watt broadcast transmitter trans-mitter operating on 1,500 kc. (200 meters). me-ters). These transmissions are purely of an experimental character and are being conducted nightly after regular broadcasting hours, the object of them being to perfect the technical details of the transmission, from a purely wireless point of view. |