Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 226
shownwithin the circles drawn on the benchesin Fig. 23. The mean of the observedvalues at the four positions nearest to no allowance has been made for thepresence of the beams. Th3 presenceof cross reflections from the verticalsides of one beam to the other would tendto reduce the effective… … FIG. 24 POLAR CURVE OF LAMP ANDFITTING USED in LIGHTING ROOM FORMANUAL TRAINING (FIG. 23) the centre of plane of reference is 53foot-candles, a disi repancy of about 21 percent. There is no doubt that this is in themain due to a shrinkage in the polarvalues on service as compared with thoseobtained…
Lighting
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