Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 275
theposition of the radial bar. A sightingpoint was fixed at F to the other end ofthe radial bar, and a fixed sighting pointwas arranged at 0. The lamp A wasset at 100 on the photometric scale,the lamj) E was adjusted until a balance 264 THE ILLUMINATING ENGINEER (sept. 1919) of brightness was… … Via 43.—Apparatus for investigation oftransmission. angles it was better to set the Lamp Aat some round number, and to move theradial bar until a balance was found,and to record the angle. A considerableelaboration of screens, diaphragms, andhoods was necessary to avoid straylight. In the first set…
Lighting
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