Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 268
30 40 50 60 70 SO Fig. 25.—Analysis of Fig. 22. … Fig. 23.—White celluloid matted, viewedplane with light. si TO 60 50 40 SO 20 10 0 10 20 SO 40 50 60 70 SO Frc. 26.—Analysis of Fig. 23. words, I moved one quarter of the wayround the instrument and repeated thetests. (This, of course, is the positionin which it should always be used inpractice.)…
Lighting
Internet Archive · University of Toronto Libraries · Public Domain Mark 1.0. Free to use for anything.
