To Transmit Vision.

Stratford Evening Post, Volume XXXIX, Issue 74, 18 July 1914, Page 5

To Transmit Vision.

SEEING BY WIRELESS. THE SUMMONS OF PRYING EYES "Your young man shall see visions, your old men shall dream dreams. There are yet old men among us who dream of the railway, the steamship, and the electric telegraph as the marvels of their youth. The middleaged speak in terms of flight, of j 'wireless,' of the motor caff," says the Pall Mall Gazette. "The young men see visions of the day when we shall talk face to face with friends half the world away, seeing their faces, hearing the tones of their voices."

We stand on the threshold of wireless telephony; Dr. M. A. Low has now demonstrated the possibility of transmitting an image of distant objects by wire, and prophesies that, in 50 years' time, the same thing will be done by wireless, not as an experiment of the lecture-room, but as a part of the converse of every-day life. TEARING THE VEIL. The process .of tearing the veil from Isis is proceeding so fast that mankind has hardly time to take breath and realise the effect which the impact of new discoveries has on his mental outlook upon the physical world. The first thought on reading of Dr. Low's invention and prophetical vision of its future development is the pleasurable one that, some day, it may be possible to converse with friends far distant, to see them in their habit as they live, to hear their voices. It is more difficult to realise the effect upon the world of ideas which must be produced ultimately by the revolution which is being brought about, in all our conceptions of time and space. The secret forces of Nature which for aeons haxe existed unsuspected are being harnessed to overcome the limitations of man. His very faith in the stability of matter is being uprooted. Yet he is still compelled to think in terms of things which are becoming unreal.

CAUSES OF UNREST. How far the ceaseless advance of science contributes to cause unrest in the social sphere we cannot say. But the disappearance of old landmarks ; the intermingling of the world of "reality" and the world of miracle cannot be without its influence. We have to look a very long way ahead to get beyond the state of universal flux. But we are entitled to believe that every, step taken is a step towards the Eternal Truth. Civilisation, which created privacy, is devouring its child says "The Times"). The telegraph, quick trams, the telephone, have made their breaches in the castle wall; and now comes Dr. Low with- the most deadly siegepiece ever dreamed of. It is useless to argue that no one is compelled to nourish in his bosom the telephone or its yet more venomous offspring. One cannot-live the modern life without the contrivances of modern life, and they are few who have the strength of mind and nerve to let the telephone bell ring on unanswered. Five years hence we shall all be rushing to answer the summons of prying eyes.

TO TRANSMIT VISION. Dr. Archibald, who is responsible for these reflections, has (says "The Times") stated his "intentioin of seriously attempting to construct an apparatus for transmitting vision that could be used in a strictly practical sense. He appears to be working on the lines tried during 1910 and 1911 by Professor Ernst Ruhmer, of Berlin, and M. Edouard Belin, of Paris, who employed a large number of selenium cells packed closely together, acting as a screen on which the image to be transmitted was projected. The intensity of light on each cell—i.e., on each small unit of the image—is reproduced at the 'receiving apparatus' through the agency of electric signals, the strengths of which are regulated in each case by the resistance of the selenium. With a- modern selenium cell the electrical resistance can be reduced to as little as one-fifth of the normal by casting a beam of light upon it, so sensitive is this metal in a certain physical state to variations in light.

TELE-VISION. Mr A. A. Campbell Swinton, in the course of an address in November, 1911, at the Rontgen Society, suggested what was then thought to be a really practical solution of the problem of "tele-vision." A miniature searchlight, as it might bo described, was to sweep rapidly over the image of the person to be seen over the wire, a lens would cast this image upon a composite plate consisting of small cubes of rubidium; at the receiving station a beam of cathode rays would similarly sweep over a fluorescent screen, rendering itmore or less luminous in each successive spot in accordance with the strength of the telegraph current as regulated by the rubidium. Exact synchronism was to be effected by means of two alternating currents, each one actuating a magnetic device, I which controlled the movements of the beam of light or cathode rays. This suggestion was, perhaps, the ifirst which, from the point of view of cost, appeared at all within the realms of practicability. Professor Rosing, lof the Technological Institute of St. Petersburg, has made a vary interest-

ing apparatus in which selenium hat been substituted by the photo-electrie cells invented by Elster and Geitel, which have recently been used with »o much success for the measurement of the brightness of faint stara.

PROFESSOR RUBMER'S VISION. "The whole difficulty so far lxa« been the reproduction on the viewing screen of the successive units of an image in a sufficiently, short time fo# the eye to see these units en maase. Rubmer estimated that 10,000 selenium cells would be required for aa a]> paratus sufficient to see by telegrapk a human person completely, and'tthat the cost would be about £500,000. The writer saw Professor Rubmer shortly before his death last year, and he then appeared confident of ultimate success at a more reasonable figure. 'I see no scientifically insurmountable reason/ he once said, 'why the Admiralty in Berlin might not be able to watch the German Armada at battle in the North Sea. ';. . It would all be a question of money.' " "Dr. Low has invented an ingenious means of doing away with a number of the telegraph wires that would ordinarily have to connect the tire pieces of apparatus, but, even »o, it is probable that, for an image of any useful size to bo transmitted, several hundred connecting wires would be necessary, thus rendering tele-vision over any great dißtanos practically out of the question," cencludes "The Times."

DR. LOW'S PROPHECY.

"The tones of the human voice, of which there are hundreds of gradations," said Dr. Low, "can be reproduced by wireless telephony. The gradations of light are far simpler tht» those of sound, and it should be potsible to devise a wireless mean* ©f transmission. I will commit myself to the prophecy that in 50 years' time people will look back with wonder at the days when it was necosaary to be at a person's side in order to see him. When this day arrives, consider how it will change the conditions of warfare. Imagine the altered methedi of military operations when you caa see what is happening miles away." Dr. Low is well known in Londoa as a consulting engineer, and has emgaged in laboratory research for the Government, say s "The Times." A number of inventions stand to his eradit, including the low high-pressure motor and a high-pressure patrol engine. The experiments in connection with light by wire have extended orar five years. "