Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 305
essels bymeans of a periscope, projecting abovethe surface of the water while the sub-marine remains submerged. spherical curvature while the interior isellipsoidal. Images of everything dis-cernible about the whole horizon are firstrefracted and then reflected down thetube. They are collected in a… … According to Popular Mechanics, in themodern periscope an arrangement is intro-duced, enabling both a general survey ofthe horizon and a detailed observation ofany particular vessel to be made. Thisis described as follows :— One of the great handicaps imposedupon the operators of modern sub-marines…
Lighting
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