Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 445
n. colour and consumption, &c., and the spot. In this way one can readilycalculation of the combined effect of obtain data which it would be hardlya number of sources, has been carried j^ossible to secure by calculations and 416 THE ILLUMINATING ENGINEER. grapliical constructions. For… … Fig. 2.—General view of instrument. the Wingen photometer for the deter-mination of horizontal illumination.But the readings of this instrument aresomewhat easily affected by the varia-tions in the height of the flame, andthe shadow of the operators body isapt to fall on the test-surface. I have…
Lighting
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