Hawkins electrical guide ... : questions, answers & illustrations : a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications ; a practical treatise (1914)
Hawkins, N. (Nehemiah), 1833-1928 · New York : T. Audel & Co. · leaf 432
delicate tints as in silk and paper mills, the light shouldbe as white as possible, while for general illuminating purposes a warmlight is best; cold glary lights, too rich in green and blue, are to beavoided. Calculation of Illumination.—The basis of illuminationcalculations is the foot candle,… … Figs. 3,472 and 3,473.—The foot candle. If A be a lamp giving 16 candle power in a horizontaldirection, the illumination at the point B, four feet distant, would be 16-i-42 = l footcandle, since the intensity of light varies inversely as the square of the distance. To getthenormal illumination at…
Electrical engineering
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![An illustration from L'optique divisée en trois livres : ou, l'On démontre d'une maniere aisée tout ce qui regarde 1. la propagation & les proprietez de la lumiere. 2. La vision. 3. La figure & la disposition des verres qui servent à la perfefectionner [sic] (1682)](https://img.insideoutlibrary.com/img/200/ia-loptiquedivise00ango-81-10.webp)
