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 119
Fig. 49.—The Wild flicker photometer. Fig. 50.—The Bechsteinflicker photometer. illuminated by rays from the left-hand source, and the outerring by means of rays from the right-hand source. If the pris-matic arrangement Kk is kept stationary, we can employ thephotometer on the equality of…
Light · Photometry · Electric lighting
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