Cyclopedia of architecture, carpentry, and building : a general reference work ... (1907)
American School of Correspondence · Chicago : American Technical Society · leaf 422
ction with this photometer. The screen is mounted infront of the opening at g, and turned so that it is illuminated bythe source being considered. Readings of the screen/ are taken asbefore. A calibration curve is plotted for the instrument, usinga known light source at known distance from the… … Fig. 59. of its construction can be obtained from Fig. 5*.l. By means of asystem of mirrors, tlie light given by the lamp in several direc-tions may be integrated and thrown on the photometer screen forcomparison with the standard, the result giving the mean sphericalcandle-power from one reading.…
Architecture · Building · Carpentry
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