Rendering Fog Transparent

Radio Record, Volume III, Issue 19, 22 November 1929, Page 4

Rendering Fog Transparent

A New Radiovision Development AN invention which should prove of immense value to shipping and to aviation was recently demonstrated in England by Mr J. lL, Baird, the inventor of .adiovision. The "Noctovisor," as tie apparatus is called, is ‘the result of a series of experiments conducted by Mr. Baird to reduce the intensity of illumination with which it was necessary to flood persons being radiovised. He discovered that by using invisible infra-red rays he was able to obtain almost equally satisfactory results. To obtain these rays he simply covered the front of the boxes containing his flood-lights with thin sheets of ebonite, which allowed only the invisible ultra-

red rays to pass. By switching ‘the ordinary light in the transmitt room, the person being televised found himself apparently in complete darkness, and yet in the receiving screen the image of his face appeared quite clearly. In the initial stages of this discovery, the phenomenon produced was regarded merely as a scientific curiosity, but during the past few months, Mr. Baird has been devoting nearly all his time in endeavouring to apply his invention commercially, His efforts have been rewarded to such an extent that several naval and mercantile marine officers who witnessed the demonstration of the apparatus unanimously declared that it is one of the most epoch-making inventions of the age. For.the public demonstration, the "Noctovisor" was set. up on top of a hill in order to secure an unobstructed view of the surrounding country. }At , nightfall, a car was despatched along the main road in the valley below. About three miles distant from the apparatus on the hill-top the car was stopped, and one of the Headlights directed towards the hill,

At a signal Irom the operator of the Noctovisor, the headlight suddenly vanished, and all was pitch darkness. The light on the car had been obliterated — by placing a sheet of ebonite in front of it. On the hill, the operator, acting as the of a supposed ship, was endeavouring by means of the Noctovisor to pick up this hidden light, which for the. purposes of the demonstration was considered to be a light-ship or a lighthouse obscured by fog. Suddenly, to the amazement/of the audience, there appeared’ on the border of the screen the first signs of the hidden light, which, as the apparatus came into focus, turned into a spot of brilliant orange light. By further adjustment to the apparatus, the operator was able to read off the exact | compass bearing of the invisible ray. The apparatus is very compact and easily manageable, and will probably displace the wireless direction-finder for use over short distances. Directionfinders, though very efficient over long distances, prove unreliable when ships are within a very few miles of one another, owing to the rapidity of movement of the ships concerned. In clear weather, an approaching ship can be seen, and steps taken to avoid a collision. In foggy weather, however, the direction-finder cannot with certainty be relied upon to overcome this danger, because the closer the spins are together, the more difficult 4 to determine accurately the position be the approaching vessel. It is in such circumstances, by ren-, dering fog transparent to navigators, that. the Noctovisor will prove invaluable. In cases, also, where it is necessary to sail close to a lighthouse or lightship in foggy weather, this new device will eliminate much of the uncertainty of blind navigation. Its application to commercial aviation, however, will probably prove. equally bene-. ficial in preventing loss of life, as its use will eliminate much of the danger and uncertainty of "blind" flying and landing in fogs.