Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 425
nes, properly illu-minated, when each line and space hasan angular breadth of 1 minute, andcan recognize Roman capital letters\\-hich subtend an angle of 5 minutes. 396 THE ILLUMINATING ENGINEER. Hence the letters of signals for the useof aviators flying 1,000 ft. above giound,should be at least 16… … Fig. 1.—Showing a sign made of glass halls exliibiled on the Terrace of the Trocadern. Pari
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