Light, photometry and illumination : a thoroughly rev. ed. of ''Electrical illuminating engineering'' (1912)
Barrows, William Edward, 1878-1960 · New York ; London : McGraw-Hill Book Co. · leaf 166
TIONS 151 zone. This method forms the basis of Macbeths polar fluxpaper, which is the ordinary polar coordinate paper on whichare placed the radial lines representing the zonal centers of 20zones of equal areas. The construction of this paper is shownin Fig. 87. The vertical distribution curves may… … Fig. 87.—Construction of Macbeths polar flux paper. mately the average candle-power throughout the zones whichthey represent. In order to use this method on polar curvesconstructed on ordinary polar coordinate paper, these radiallines may be drawn as in Fig. 88,^ on transparent celluloid…
Light · Photometry · Electric lighting
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