Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 539
piral arrangement gave us something muchmore nearly approaching the idealpoint-source desired for optical pur- \o\v coui,- the half-watt auto- mobile lamp with it- coiled filament in a gas-filled bulb which is stated to he tight tit/us as efficient as the old carbon fila-ment lamp. Tin- effect of… … THE ILLUMINATING ENGINEER (nov.) 525 135 150 185 160 (63* ISO 135*
Lighting
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