LAMP CLEANING.

Auckland Star, Volume LXIX, Issue 96, 26 April 1938, Page 20

LAMP CLEANING.

INCREASED EFFICIENCY. DESIGNERS' TROUBLES. As the result of experiments with various plated surfaces in respect to their reflective charauteristics in the headlamps of automobiles!, an interesting fact was recently disclosed by the well-known EnplUh automotive expert, Dr. A. H. Stuart. He stated that, although it was quite true that all the light in motor headlamp beams came, from the. filament, of the bulb, it was not generally realised how little of it came directly from that source and how the intensity of the beam was really dependent on the efliciency of the reflectors in headlamps. Actually only a small fraction of one per cent of the light from these lamps came from the filament, the balance coming off the reflecting surfaces of the lamp. From this, it would bo realised how vital was the reflectivity of the reflectors of a lamp and the necessity of keeping them untarnished and free from dust. One of the problems lamp manufacturers have had to contend with is the tendency of .silver plating to tarnish from exposure to the air; to prevent

this an almost invisible lacquer is used to protect the silvered surface. H is for this reason that any attempt to polish the reflectors of 'headlamps is likely to rub off the very thin coating of lacquer and lead to 'tarnishing the silver-plated surface. Silver is a gowd reflector only when it i.s bright I v polished. Once the air gets" at it, tarnish sets in, hence the need of care not to damage the lacquer coating when lightly dusting out the interior of motor lamp?. As brilliant reflectors and incidentally clean lenses have a big effect upon the comfort and safety of night driving, an occasional dusting of the interior of these lamps and the cleaning of the glasses will materially help their eflieieney in road illumination.