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 184
promise can be made sufficient for all practical pur-poses if the lamp is not supported at the center but at a distanceof 8 or 15 per cent, of the diameter from the top of the innersurface of the sphere, also by making the globe very large. The construction of this photometer is shown in Fig. 98… … Fig. 98.—The globe photometer. Experiments with globe photometers give results very con-sistent with those obtained from point-to-point readings, andtests of a great many different sources of light show that themean spherical candle-power can be obtained by this arrangementwith an error of not more…
Light · Photometry · Electric lighting
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