The standard electrical dictionary : a popular encyclopaedia of words and terms used in the practice of electrical engineering (1898)
Sloane, T. O'Conor (Thomas O'Conor), 1851-1940 · London : Crosby Lockwood and Son · leaf 419
Fig. 262. Rumfords Shadow Photometer. intensity of the two lights is estimated by the intensity or strengthof shadows of the same object which they respectively cast. … Fig. 263. Rumfords Shadow Photometer Arranged for TestingIncandescent Lamps. A rod is supported in a vertical position. Back of it is a screen STANDARD BlyKCTRICAIv DICTIONARY. 415 of white paper. The two lights to be compared are arranged infront of the rod and at a little distance from each…
Electricity
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