Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 109
in. diameter in one or two shortlengths, the filament being much morecompact. The bulb is filled at a verylow pressure with an inert gas whichwill not chemically combine with thematerial of the incandescent filament.but which serves to conduct awav heatand allows the filament to be run at ahigher… … FlG. 3.—Showing how a parabolic reflectordistributes light from a spherical source. Each point of the reflecting surface is atthe apex of a right circular cone of lightwhich touches and embraces the sphericalsource, and the same point is also at the apex of a reflected cone of light havingthe same…
Lighting
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