MOTOR NOTES

Bay of Plenty Beacon, Volume 1, Issue 6, 3 May 1939, Page 6

MOTOR NOTES

o DAZZLE CURED NEW "POLARISED LIGHT" CAR DRIVING SAFER The biggest single danger in night driving is the dazzling ell'ect oi' a car's headlights when directed at another driver's eyes. In town areas it is made worse bv the multitude of illuminated signs which abound in the streets; while in wet weather the reflections of all types of light in the rain-soaked pavement makes driving a great ordeal. A complete cure for headlight dazzle exists, but its adop. tion at the moment bristles with dU. ficulties, of which the most important is that every single car on the road must be equipped with a spec, ial type of glass in the lamps and windscreen, otherwise the system fails. In this, the beams emitted from behind the lamp glasses are known as "polarised light." In explanation of this term it may be stated that ordinary light consists of \ibiation,s> but these vibrations are not all in the same plane. Light when passing through certain materials, behaves almost a:" though it were passing through a series of very narrow slits. If a polarising material is placed in front of each headlamp so that the slits run from the top left hand to the bottom right hand at an angle of 45 degrees, and a similar arrangement is placed in front of the windscreen, a car travelling in the opposite direction, equipped in the same way would have these slits at direct right-angles, simply because his vehicle is pointing the other way. Each driver can proceed comfort, ably behind his own headlights under all conditions, because when the other car is met, the lights irom its lieadlights will not dazzle, simply because its vibrating waves cannot pass through the slits, which are at right angles to the plane of vibration of the other lights. But th<: approaching car itself can be seen. Not So Simple However, the solution is not acta, ally as simp'e as ail that. Unless the two polarising materials have their slits exactly at right angle; some light from the other headlights will filter through, and cause *Lccr - tain amount of dazzle. And it 'will be realised that variations in roacl camber will cause this condition. This trouble has been cured in a peculiar manner by an American invention. Behind the polarising screen is placed a sheet of plastic material. The polarised light passing through this in the form of a flat ribbon has a spin imparted to it, so that it oe. comcs like the thread of a deeply cut screw, and this, striking the screen of tlie oncoming car, which also has a plastic sheet behind it, passes through and straightens out to the angles of the slits through Avhicß it penetrates. Thus accurate setting oi different car screens is uot needed. The polarising material does net actually possess slits, the term beinJ used for the sake of clarity. Tht polarising material is glass whose crystals are not scattered in all di. rections, as is the case with ordinarv glass, but by a special process oi manufacture are made to lie parallel to each other. It is these invisible crystals which ret like slits. Great Importance The importance of this development cannot be over-estimated. Photc graphs taken at nigh I time arc in existence which show how the daz/Je is cut out completely, and the on. coming car remains completely delineated. Unfortunately, it is uso. less unless every ear on the road equipped, and this obviously eoul.i only be done at once by legal com. pulsion, assuming that enough sets of headlamp'"'and windscreen polaroid glasses were available, which they are not. However, it appears to be delinitv: that polaroid glass eventually will be fitted to all motor vehicles. It is understood that plans are already in existence by car manufacturers lithe U.S.A. to standardise the mate--, ial within a very feAV years. Eng. lish authorities are displaying a ven lively interest in it. One minor disadvantage is tha; light, when polarised, loses a gooi deal of its intensity, and that wil ipp'an more powerful electrical equip meat as a compensation.

THE DROUGHT ENDS

WET \V HATH Ell PRECAUTION { | The Bay of, Plenty drought has end. g ed and it seems that the wet wca_ ther may last some time. Consequently motorists may appreciate the foilnwi n g advice: V\*hcn a cur is driven considerably in wet weather, the owner, as .soon as Oner days appear, should have the car thoroughly greased. And it does not matter whether it was lubrieat, ed all over immediately before the rain, the advice still holds good. The reason is that a surprising amount of water finds its way into the chassis bearings when driving on a thoroughly soaked road, and to prove this, the owner has only to apply the oil gun himself to the chas sis after a downpour, when he will be shocked to see the amount of water that is forced out of the bear ings by the fresh oil going in. This water Avill cause squeaks all over the chassis and may even cause rust on the polished surfaces of the spring pins. The sooner it is removed the better. "FLIVVER DUMPS" GO ARMAMENTS BOOM RESULT The "flivver dumps" usually seen on the outskirts of every big town in America are disappearing. It was to these autograveyards that old cais were driven and abandoned. But now the dumps are being cleared. The armaments boom has sent scrap metal prices rocketing. So day and night lorries are travel ling the United States collecting metnl from these dumps.