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 58
d illustrate the factthat visual acuity is quite a variable function. Curve III rep-resents the mean for the observers eye. Curves IV and V wereobtained by two other observers and represent the mean of a lessnumber of readings. The illumination maintained throughoutthe experiment was 4.2… … .420 .440 .460 .480 .500 .520 .540 .560 ,580 .600 .620 .640 .660Violet Blue Green Yellow Orange Red Fig. is.—Variation of visual acuity with wave-length of hght. While it may seem to some that the acuity method is the onlyvalid one for comparing the illuminating values of light, it mustbe…
Light · Photometry · Electric lighting
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