SEEING BY WIRELESS

Evening Star, Issue 19663, 16 September 1927, Page 2

SEEING BY WIRELESS

how mr J. l Baird discovered TELEVISION Mr J. L. Baird, the inventor of television, gave a lecture on television recently under the auspices of the Edinburgh Empire Exhibition. Part of the lecture was broadcast. Mr Baird, defining the ■word television,” said that it meant, simply exgessed. vision by telephone, or by wiress. A televisor did for the eye what the telephone or wireless set did for the ear, and allowed ua to see as well_ as hear the person who was telephoning or broadcasting. When we were actually transmitting, the person being transmitted sat m front of an apparatus corresponding to the microphone of a telephone. _ Tins converted the image of his face into a fluctuating current. These image currents could be heard in a telephone as sounds, every face or scene having its corresponding sound. The fluctuating current was transmitted to the receiving station to an apparatus called a "televisor. _ Here the current controlled an electric lamp behind a device which gave exactly the reverse effect to the analyser, and built uo the little flashes of light into a complete picture. STORY OF THE DISCOVERY. About five years ago, Mr Baird said, ho had decided to devote his entire time to an effort to achieve television. He commenced by attempting to send mov- 1 ing shadows, and after about six mouths was successful. The step from shadows to true television proved a very difficult one. The problems involved were of a highly technical nature; but, without going more fully into the matter, «e might say that the outstanding obstacle was the lighting difficulty. In the autumn of 1925, however, a way out of the remaining difficulties opened, and one Friday afternoon the head of the dummy used as an experimental model, instead of appearing on the screen as a mere black and white outline, capie through a real image with gradation if light and shade and detail. ‘ Experimenting with a human subject office hoy from the office beneath j-he gave the hoy half a crown “in the excitement of the moment,” and at last,.succeeded in obtaining a clear picture of the hoy's face on the screen. It seemed a pity, the inventor remarked, that the first person ever seen television should have to he bribed with half a qrown to achieve the distinction. DIFFICULTIES SURMOUNTED. On January 27, 1926, he demonstrated television to some forty members of the Royal Institution. . Several members had their faces televised, but Complained about the dazzling light under which they had to sit, In suhBMnent researches ho went on slowly aeducJna the amount of light necessary, hi in ■fami lii I Ti ' ' '

infra-red rays, which are invisible to the eye but visible to the photo-electric cell, and have no bad effect on the human body, and pass readily through glass. In December of 1926 ne invited the Royal Institution to come and see television demonstrated in total darkness, and it was during this successful demonstration that a chance remark of one of the members led to an investigation which, he hoped, would have useful commercial results in tho future. NOCTOVISION.

At the first demonstration in 1925 one of the features had been the transmission of a view of a boy smoking a cigarette, and ono of the members had been impressed by the clearness with which the puffs of smoke were reproduced on the receiving screen. At the second demonstration he asked to see the boy smoking again, so that he might see what the effect of the infra-red rays was on the smoke. During the experiment the smoke was invisible, smoke and fog being transparent to infra-red rays. Yellow r and red light penetrated fog very much'better than blue light, and the more red the light the better it penetrated. ,Fog was not absolutely transparent to infra-red rays, but they penetrated < it about sixteen times better than visible light. He was hopeful that the application to shipping of the infra-red television apparatus, or the “ Noctovisor,” would prove an assistance to navigation during foggy weather. In an interview with a Press representative Mr Baird stated it is hoped that in time an instrument, the combination of phonograph and television apparatus, may bo available to the public. By coupling the gramophone with a television apparatus it will he possible for the onlooker to hear the sound and see the origin of the sound —a person singing or speaking pr playing a violin, the movements coinciding exactly with the sound, as in the case of the phonofilm.