Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 445
esia screen providedwith this photometer. For weakilluminations, however, it is preferableto substitute for this a glass plate,mirrored on both sides. Fig. 2 shows a general view of theinstrument. F represents the Lummer-Brodhun arrangement «ith lateral win-dows, to which are attached… … Fig -Showing vertical sectinsolide d^clairement. of the from outside, and may be read on ascale S attached to the tube e.xternally.The other shorter tube T carries arod t, terminating in a pivot at P,wliich is at the centre of the graduateddisc C. A is a standard screen illu-minated by the lamp L ;…
Lighting
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