TESTING FOR GLARE

Dominion, Volume 10, Issue 3190, 14 September 1917, Page 7

TESTING FOR GLARE

IN MOTOR-CAR LIGHTS INTERESTING EXPERIMENTS A good deal of attention is being paid to the problem of glaring head-lights on motor-cars all over the civilised world, and naturally in Wellington, witli its harrow streets, : the spread of the giaro of the big motor-car lamps has caused an outcry against the motorists' latest ■frightfulness. But the problem is ono whioh has, to be looked at from tho driver's seal, as well as from the public sidewalks. There may be more danger for- the publio if a driver is ill-provided iVith head-lights than.if he had super, glares, for the simple and oft-forgotten reason that of air vehicles traversing pur roads the best controlled (when in charge of a competent driver) is the :;.otor-car. About 70 per cent, of the public are inclined to believe that a good proportion of motorists are madmen, with an appetite for devouring distance in tho quickest time that there is no appeasing—he rushes to nowhere and buck without tho slightest object save to feel the wind whistle through his air and to give the oil company a reasonable prospect of dividends. The other point of view is equally quaint. The motorist has the notion that the average member of the public is a hazy-minded, befogged individual, who wanders off the sidewalk and along the road to see Low long he can .avoid accident or death. There may be excuses for both points of view, just as there are arguments in favour of and against .Jjig' head-lights. The City Council has been struggling with the question for.the last few weeks, and hopes sooner or later to come to some definite 'conclusion with regard to glaring head-lights as a nuisance to the public without unduly handicapping the drivere of cars. To that end the corporation's motor expert (Miv L. S. Drake) has been conducting some experiments with various kinds of - lamp lenses. To do this he has fixed up a couple of ordinary motor 'lamps (having lli.c.p. lamps)-'in a passage in the basement of the Town Hall, and there;, by noting' the position of the central beam thrown by the lamp through this or that lens, and by also taking a clear impression/of the distance of the beams from the car, and the comparative density of tJjp shadows thrown by. the lamps on 'tue. white wall at the farther ond ot the- corridor by persons standing be tweon tue light and the wall, a very good idea may be obtained of tho virtues of file lens as n beam deflector.. ' As Mr. Drake suggests, it is tho simplest matter to dim down a IHit— particularly an electric light—but dim lights are dangerous for tho driver and tlio public. The motorist must l.avo a good fight, : thrown- some distance ahead of Ins fast-moving car, otherwise the motor-lamp would fail in its mission, bo Mr. Drako thinks that the solution of tho problem-lies in the adoption of a lons which will eliminate Hie glare from people's eyes by throwing the-beam on. to the road soma, 15 to 20 feot ahead ot tho car, whilst a diffused light, which can be looked at without dazzling ojic, throws;a softer light well ahead of tho beam spot. Ho demonstrated what ho meant by placing on one lump a lens, tho inside sections of which wero concave, whilst on tho top half of rho outside wero lateral prisms, calculated to control tho beam and deflect it earthward from the centre. Standing 20ft. i'h front of this .light ono could look it lull in tho face," but by stooping down close to the floor the beam spot could bo picked up in all its intensity. That. 16 to say, that whilst; tho lop' Lalf of the lens was responsive to a diffused light, which shed its radiance 70ft. or 8011. away, the beam centre was only l?fl. or 16ft. away from the car. A moro heavily prismed lens was .hardly so generally effective. Another lons was simply a pretty pattern in low relief glass nobs, ■ working out in rings from the centre.. This, oa being tried, was' found (o be merely a diffuses of light, and did not exercise any control over the beam. It was oven less satisfactory than a piece of ordinary Murano glass, which' emitted a good, steady light without a. glare, killing the beam spot altogether. A piece of ground glass (frosted) was'next placed in iho Inns frame. The light it ebed lacked lustro of any kind, and its use would probably mean tho hospital or sudden death lor the occupants of the cur travelling at any rate of speed. A piece of Murano glass was also tried. This shed a light like burnished gold, useless, perhaps, in fine, clear weather, but more effective, than all the white lights in a. fog. Indeed, in London special gold-plated reflectors are obtainable for lamps in order to get those yellow rays that are so penetrating in thick weather. A demonstration of the testing pl.'.iit is to be given before tho By-Laws Committee of the City Council this afternoon.