Light, photometry and illumination : a thoroughly revedof ''Electrical illuminating engineering'' . Fig. 111.—Sporadical Fig. 112.—Uniform iilimiina-tion by overlapping straightillumination curves. formly illuminate a circular area as indicated in Fig. Ill, and theareas between the circles shown shaded in the figure wouldreceive no light. It follows, then, that the polar candle-power distribution mustbe modified and the lamps so placed that the illumination due ILLUMINA TION CALCULA TIONS 209 to lamps near one another will overlap. Such a condition isrepresented by Fig. 1
Light, photometry and illumination : a thoroughly revedof ''Electrical illuminating engineering'' . Fig. 111.—Sporadical Fig. 112.—Uniform iilimiina-tion by overlapping straightillumination curves. formly illuminate a circular area as indicated in Fig. Ill, and theareas between the circles shown shaded in the figure wouldreceive no light. It follows, then, that the polar candle-power distribution mustbe modified and the lamps so placed that the illumination due ILLUMINA TION CALCULA TIONS 209 to lamps near one another will overlap. Such a condition isrepresented by Fig. 112 where the small circles represent thelocation of the lamps and the large circles concentric with themrepresent the areas illuminated by the respective lamps. It will be readily understood that in oider to secure approx-imately uniform illumination with a number of lamps theillumination due to each lamp must decrease with departurefrom beneath the source. Polar candle-power curves of differentshapes whereby these conditions may be realized are shown inthe following illustrations. To simplify matters considerationwill be given to onl
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectlight, bookyear1912
