An Original Anti-dazzle Lamp Bulb
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FROM time to time many methods of combating the :dazzle danger have been brought forward; one of the' Most simple.Principles is that of using a lams bulb .of. special design, so as to -tackle the trouble at its source. This plan, of course, relieves the driver of the responsibility of actuating any control.
An interesting lamp bulb of this type is the Fenbo Anti-Dazfog, handled by W. J. Bithell, Ltd., 41, Whitehall, London, S.W.1. Bulbs for headlamps cost 4s. each and those for side lamps are priced at 2s. each ; at 12s. a complete anti-dazzie equipment cannot be considered in any way expensive.
The base of the bulb is, of course, made in conformity with standardized dimensions. The rear portion of the bulb is of globular formation, the surface of the glass being noduled; the V-shaped filament is contained entirely within this section of the bulb. The forward portion of the glass is smooth and convex, the glass being amber tinted. The
nodules or crystals of the glass break up the rays of light, each ,erystal, it is claimed, throwing a magnified but diffused beam of its own.
The amber light is especially useful in fog; it should be noted that it is thrown forwards by the reflector—there is no light absorption as occurs when a white light is turned into an amber one by its passage through a lamp front of that tint.
Interesting and satisfactory results of the use of these bulbs are revealed in the report of an R.A.C. test. In brief they are as follow: A driver using lamps equipped with Fenbo bulbs, when approaching a pedestrian so dressed as to be seen only with difficulty, would be able to see him when 284 ft. from the car, provided he was no farther from the centre of the beam than 15 ft. {half its width).The driver would see a pedestrian stepping off the kerb into a road 30 ft. wide when 214 ft. away. When approaching the lamps the
blinding effect ceases when 65 ft. away from them, the eye-level being taken as 4 ft. 6 ins.
At 8 ft. from the ground the length of beam is 244 ft., whilst at 1 ft. 6 ins. above the road surface the beam measures 813 ft. Thus it will be seen that the beam is of a useful length for fast driving; certain anti-dassle devices are apt unpleasantly to curtail the beam. The width of the path of light is actually greater than with some types of plain bulb. The current consumption is no greater than the normal; focusing is simply effected.