A BLACK LIGHT

Wanganui Chronicle, Volume LXXXIII, Issue 19772, 21 February 1927, Page 7

A BLACK LIGHT

INVISIBLE AT NIGHT WILL PENETRATE FOG REMARKABLE INVENTION. [By Telegraph—Per Press Assn.—Copyright.] Received Feb. 20, 5.5 pun. LONDON, Feb. 19. Mr John Baird, of Glasgow, a leading research student in connection with television, announced that in consequence of widespread international interest, including America, Germany and France, he is constructing a full-sized model of his new black light, which consists of a powerful ray like a searchlight, invisible in darkness, yet brilliantly illuminating anything on which it j thrown. It even penetrates fog. Mr Baird says he will be able to pick out aeroplanes over London at a height of 6000 feet. UNSEEN SEARCHLIGHT

TELEVISION DISCOVERY. EFFECT ON FUTURE WARFARE. 1 ■ A special correspondent writes in the London Daily Mail:— Accompanied by a colleague, I was permitted to take part in a first demonstration —apart from secret tests before naval, military and air force officials — of seeing in total darkness by means of an invisible ray. Mr John L. Baird, inventor of the Baird ‘ 4 televisor, ’ ’ who gave the first demonstration of television on January ’27 this year, is the producer of this invisible ray, find describes as follows the experiments leading to its application:—

“In my first demonstrations of television it was necessary for the person being “transmitted” to sit before an intensely bright light. Its intensity was so great, in fact, as almost to blind the sitter . Before, therefore, my ‘ televisor ’ could be feasible commercially it was essential that this enormously brilliant light should be dispensed with. “For six months I have been concentrating upon reducing the brilliance of the lighting and with such success that it is now possible by my 1 televisor’ to see a person who is sitting some distance away in total darkness. This is accomplished by isolating and employing Pays which are outside the visible spectrum. The human eye cannot see them, but the sensitive 1 electric eye’ of my apparatus detects them radily. Rays .Sent By Wireless. “In the demonstrations my colleague sat in. darkness before the transmitting screen on the ‘televisor.’ Above his head, shut off by an enclosed space from the room, were a certain number of ordinary electric lights. The rays from these impinged upon a light filter. “This filter extracted everything that was visible from those rays, and only allowed to pass into the room certain rays in the lower spectrum, invisible to the human eye. Those unseen rays bathed my colleague’s head and shoulders without his being in the I least conscious of the fact, and after I they had been ‘analysed’ by an apparatus in front of the transmitter were flashed ’by wireless across an intervening empty room to the sensitive cell of Mr Baird’s ‘televisor.’This was installed in a third room; it had been adapted specially to record those rays and to project them in a visible form upon a screen.

“In the receiving room I sat in total darkness before the small screen. On it flickered and then clarified the easily recognisable head and shoulders of my colleague as he sat in the other room in pitch-dark. He turned his head, as we hadagrecd he should, opened and shut his eyes and drew back and then approached nearer. The fidelity of the 'image was perfect. Astounding Possibilities. “I was accomplishing the apparent miracle of seeing a distant person in the dark who was illuminated by a ray invisible to the human eye. This ability to sec by means of rays unseen by those upon whom they are turned opens up astonishing possibilities. ’ ’ “It is difficult,” said Captain O. G. Hutchinson, who is associated with Mr Baird, “to estimate what may be the importance in war of this invention. It becomes feasible to follow an enemy’s movements when he believes himself to be in darkness. Attacking aeroplanes approaching under cover of night will be disclosed to the defending headquarters by the electric eye of the ‘televisor.’ They will be followed by searchlights emitting invisible rays, and as these rays will be unseen by them they will continue to approach until, without warning, they are brought down by the guns of the defence. “Darkness, that cloak of military operations, will give security no longer, creeping forward for a surprise assault in pitch blackness, an attacking party will be swept by an invisible ray and watched on the ‘televisor’ screen of the defenders. The attackers will be allowed to come well within range and will then find themselves, in spite of apparent darkness overwhelmed by gunfire. ’ ’ Fog Penetration. The invisible ray, Mr Baird explained, could be focussed and flashed through lenses like an ordinary searchlight, but owing to its nature it would !be more penetrative and could be thrown further than any other visible ray.

For naval, military, or flying purposes it would be used in conjunction with a special receiving screen or I “eye” upon which would be focussed an image of tiny distant object upon which the invisible searchlight was turned. The nature of the rays would also enable them to penetrate fog more readily than any other form of ray, and in this respect they might have great significance commercially in the operation during foggy weather of sirtps, trains and aeroplanes.