IT GLOWS IN THE DARK

Bay of Plenty Beacon, Volume 5, Issue 54, 18 May 1942, Page 2

IT GLOWS IN THE DARK

MILLIONS OF GERMS EXPIRE A paint that glows in the dark is liciniL* used I'or showing up' objects in London's blackout, and it foreshadows: gerjnless houses iii the future. To "activate" the paint, ultra-vio-let rays generated by specially filtered filament lamps are thrown upon it, when the object painted gives out a bluish glow and becomes visible in the dark. The system is being experimented with by London's Underground system, and, in the entrances to four stations' in London's West End. stair-risers, bull's eye signs and indication strips have been treated, and further tests are being caried. out at a trolley-bus depot where a track will be treated to guide the trolley-buses into the depot. The principle of "fluorescence" or the generation of light by any substance under ultra-violet rays, was discovered by an Englishman. Sir John Ilersehel, one hundred years ago. Its war-time application may lead to its extensive use in painting the walls of rooms with fluorescent paint, which, when activated gives off light approximately three times more effective than filament lighting. It can be so arranged that the wavc~ length of the exciting light not alone causes the paint to fluoresce but also kills off bacteria in the atmosphere. If the present blackout experiments prove successful, the lluorescent paint will be made use of in a variety of ways, for example by illuminating the platform steps ol buses, edges of railway station platforms, and tramway junctions. Alveady many private business houses have installed the system for lighting entrance halls where the street doors have to be opened in the blackout.