Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 204
han 60-watt gas-filledlamps are assumed. The chart alsoallows for 30 per cent, depreciation inillumination due to deposits of dust onlamp and reflector, aging of lamps, etc.If the conditions are such as to make itlikely that this deterioration will beexceeded, appropriately larger unitsshould be… … <A A -j - K « vlo n id oq:^ * ~> 3 a 2 - - ui ■ n ra _ a- « u> ° 3 4,^-a, o o <* a q^o 2 q.«» 3 * ° ° -•,0^3 3 o ao •+ =V i1!3 «ion +2.o i 1 w 194 THE ILLUMINATING ENGINEER (jui.y 1919) in some cases vertical illumination mustalso be considered. The ratio betweenillumination in a…
Lighting
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