Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 112
le commercial manner.This may be illustrated by reference toa simple diagram, Fig. 5, showing asource of light, S, a condensing lens,C, and a projecting lens, P, in whichthe condensing lens is placed atabout the focus of the projectinglens while the condenser is of such astrength that an image of… … FlG. •*).—Showing use of lease- to obtain definite line of demarcation betweenLight and darkness. diameter of a smaller lamp will meana smaller reduction in the amount ofprojected light. It is thus possible for aSin. diameter lamp of short focal length illuminated condenser at some consider-able…
Lighting
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