File:Light and lighting (1908) (14597221110).jpg

Identifier: lightlighting07illu (find matches)
Title: Light and lighting
Year: 1908 (1900s)
Authors: Illuminating Engineering Society Association of Public Lighting Engineers (Great Britain)
Subjects: Lighting
Publisher: (London)
Contributing Library: Knox - University of Toronto
Digitizing Sponsor: University of Toronto

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URCH UGHTinQ, FlQ.e This angle is 39° 10, giving an areaon the reference plane of approximately1700 square feet. 200 THE ILLUMINATING ENGINEER (april)
Text Appearing After Image:
THE ILLUMINATING ENGINEER (arun.) 201 values show a heaping up of the illumina-tion towards the middle of the room.The figures are given in Tablj VI. Table VI.Comparison of Kesults. Fig. 11. Position. Calculated value of horizontal illumination. Observedvalues. A.BC. 1-601-44 1-88 1-51-51-5 falling off in illumination in a space of18 days continuous use varies from18*5 per cent, to 45 pei cent., dependingon the conditions of service. The estimation of the mean horizontalillumination by the flux method is inthis case particularly easy. The sym-metrical arrangement of the points, andthe flat plane of reference, neglecting theactual booking office, make it unnecessaryto draw cones for more than two lamps,as shown in Fig. 11. The summation isshown in Table VII. Hence flux for 8 lamps=4x9513=3805 lumens.

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