Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 442
3C 20 10 o to ao 30 Fig. 11.—Polar Curve of Inverted Mantle with Opal and Clear Optic Globe. THE ILLUMINATING ENGINEER. 427 … Fig. 12.—Polar Curve of Tungsten Lamp inPrismatic Glass Sphere for upright use. adds very little to the mean sphericalintensity, but it may be of value incircumstances demanding a localisedbright patch. The percentage losses inthe above table are apparently too lowfor the given materials—obviously…
Lighting
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
