Cyclopedia of architecture, carpentry, and building : a general reference work ... (1907)
American School of Correspondence · Chicago : American Technical Society · leaf 415
he area of C, distant two units from the source of light A, is four times that of B which is distant one unit. The Lummer=Brodhun Photometer. In addition to the Bunsen Screen described, there are several other form.s of photometers, the most important of which a? is the Lummer-Brodhun. The… … Fie:. 53. 345 64 ELECTHIC LIGHTING screen which reflects the light falling upon it from L, to the mirrorM, when it is again reflected to the pair of glass prisms A, B.The surfaces sr are ground to fit perfectly and any light falling onthis surface will pass through the prisms. Light falling on…
Architecture · Building · Carpentry
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