VISION OF TELEVISION REALISED

Manawatu Times, Volume 60, Issue 196, 21 August 1935, Page 16

VISION OF TELEVISION REALISED

-£JNLIKE many other wonderful inventions which have taken 20 or

30 years, or even longer to como to fruition, it is only 12 years since John Logie Baird, a Scot, as you may guess from his name, decided to devote the whole of his time and means to television, says Colonel 11. G. Kennard. Thirty years ago Nipkow saw television in theory and invented the spiral disc which Baird uses to-day. Weller invented the mirror-drum which forms part of the apparatus. But Baird was tho first man in Great Britain to show actual results and his system is one of those selected to be operated by the British Broadcasting Corporation in 1.935.

It was in 1925 that the writer first heard of Baird getting actual results from experiments in television. Inquiry located him in a small house in the .Soho quarter of London. A question ou the second floor as to whether this was Mr. Baird’s place elicited 1 the reply, "Oil, you mean Sparks. No, he’s next floor up. Take care you don’t get blown up." And sure enough, there was the inventor occupying two small rooms on tho top floor. He had been warned of the object of tlic visit, so was prepared. His work table looked a mass of wires, batteries and electrical gear, with a large disc perforated with holes as the principal item. A bicycle’ chain did duty for driving the disc. Altogether it looked a strango contraption with which to produco television. But Mr Baird explained that he would prove he could produce it, and showed how the outline of a silhouette cut from cardboard held in front of his transmitter would be seen on a hooded screen of a receiving apparatus in tho next room. Tlio next thing was to set the apparatus working. When this happened such a clatter ensued that one thought everything must come to pieces. Hurrying to the receiver in tho next room one could see first tho outline of an open hand, and then of two or three cardboard profiles which Mr Baird held in front of tho brilliant electric light. "You see I really have got television," he said. “Though it is only on a wire connection from one room to another, it is only a matter of development to send it by wireless from one place to another, miles away." Tlio following year, 1926, saw tho first demonstration in Great Britain before members of the British Association when living faces woro tolevised. Big headlines in the papers announced that television had arrived. A small syndicate was formed to back tlio invention on which Mr Baird had spent his all, and in 1926 tho first public company was formed. After that there were successive demonstrations, each showing an advance on the preceding one. In 1930 television had a fortnight’s turn at a London variety theatre where tlio faces of several well-known people wore thrown on to a screen, having been transmitted from tho Baird laboratories about half a mile away. Members of tho audience were allowed to ask the person to "Put out your tongue," "Shut your eyes" and so on, just to convinco the sceptics. This was followed by similar demonstrations in Berlin, Paris and Stockholm. In 1931 the finish of the race for the Derby was seen in the magnifying lens of tho early typo of televisor, and in 1932 tho Derby finish was again shown, but this time on the screen of a cinema. Earlier than these was the occasion on which the chief wireless operator of the Berengaria, then in mid-Atlantic, was enabled to see his fiancee who was in the Baird studio in London.

Experiments Bear Fruit

And how is television done? Tho picture to be taken, whether it bo a scene or a face, has to be "scanned." A spot of brilliant light is made to traverse the picture from side to side. Tho number of scanning lines to tho inch determines the high or low defini-' tion of the resultant picture. Ad'dcd to this is the number of times per second tho wholo picture has to be scanned. Hitherto in England Mr Baird has used 30 lines to tho inch and the picture has been scanned 12 J times per second. This was because he has been limited to tho use of tho ordinary medium wavelengths and could not "spread himself" on either side. This disability has disappeared now that ho works on ultrashort wavelengths round about seven metres. In 1934 a committee, appointed by the Postmaster-General to’ investigate the question of television for a public service, recommended a standard of 240 lines to the inch and 25 ‘frames," or complete scannings of the. picture, per second. This has given quito excellent results, tho picture, some 12 x 9 inches id size, being comparable in clarity to those seen on a cinema screen, but in miniature. Tho lines of light in the scanning can bo produced in three ways—(l) by a rotating disc with holes through which the light passes; (2) by a mirror drum; or (3) by a combination of photo-cell and cathode-ray tube. Mr Baird says, that he has experimented with as high, as 400 lines to tho inch, but that the result is very little better than 240. But it is worth remembering that what appears on the screen as a moving picture is made up of a scries, each being produced by a spot of light travelling at immense speed over what is to be produced, and then presented to the viewer so much faster than the human eye can take it in that,, as ia a cinema, the picture appears to be moving. Tho point, however, upon which popular interest centres is what the lookerin, the televiewer, or the televisionist is going to see when ho has got his rather expensive apparatus. Mr Baird has shown at hi-s latest demonstration that a cinema film, a studio scene, and a scene of horses jumping in a field can bo successfully dealt with. Before these were shown the announcer’s face appeared on tho screen to give out the items on the programme.

When asked liow long it would require after tho taking of a film of some current event before it could bo put on tho air for television, Mr Baird’s astonishing reply was 35 seconds. That ia tho record ho said, but to bo on the safe side, gay a minute. A combination has been invented with which, the cinema film is photographed, passed direct into the developing and fixing bath, and thence into tho television transmitter. When asked if this operation included tho making of tho positive film, Mr Baird smiled and said that no positive was necessary because the visible picture was turned into an electrical equivalent by transformers and was thus unaffected by the question of positive or negative. On the screen it appears as a positive.

And so, as a correspondent to tho Press recently said, wo may soon hear such a conversation as this: A. Shall you teleview the Test Match to-morrow? Ik I didn’t know it was going to bo televised. Anyhow I am not a tele-« viewer as I have not got a radioscpc. A. That’s a pity. Televiewing is almost as good as being thero and this will be the first tele visible Test Match. Come round and seo it in my radioscope.