THE EYE OF DEFENCE

Hawke's Bay Herald-Tribune, Volume 81, Issue 49, 20 November 1937, Page 15

THE EYE OF DEFENCE

Piercing the Fog Screen

Inventorg in many countrieu have •hnost eimultaneously golvcd the problem of detecting material objects bidden from the eye by cloud or fog, and practieal use on a limited scale is being nade of the discovery. The solutions of the problem are . simttar to each other, but with variations in detail. An English inventor, Mr.- F. D. Aldridge, bases his on the use. of light-wave^ slightly longer than those of the infra-red series. Every golid object radiates light waves- from its surface, and these waves include those to which the hjipian eye is not sensitive. The various apparatus of diffcrent inventors convert such rays into visual or aural signals, Aeroplanes have heen "seen" through fog by this means, and the appaiatus can'be ren5*red sufficiently sensitive to detect

aircraft at a cjstance of eome miles. Hills and ships present no difiiculty, and it is obvious that the use of such an instrument should enable airmen off their course to avoid hitting hills iupposed to be miles a^vay. By robbing air raiders of their prineipal advantage of being able to choose cloudy weather for their operations, fence, this meehanical eye promises to discourage them. It will have been gathered from recent ofiicial statements >that the prospeets of defence against aid raids have much improved. Doubtless the "eye" of defence is ono of the metliohs which are being developed. It is not siifficient, howevter, merely to kpow of the existence of such methods. The necessary oquipraent is as necessary as are guns, searchliglits. and aeroplanes, J