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Light, photometry and illumination : a thoroughly rev. ed. of ''Electrical illuminating engineering'' (1912)

Barrows, William Edward, 1878-1960 · New York ; London : McGraw-Hill Book Co. · leaf 68

An illustration from Light, photometry and illumination : a thoroughly rev. ed. of ''Electrical illuminating engineering'', 1912, leaf 68 — nd of the bar where it may be replaced by the lamps to bemeasured after checking the intensity of the kerosene lamp. The Hefner Lamp.—^The two most successful primary flamestandards are the Hefner amyl acetate lamp and the Harcourtpentane lamp. The Hefner lamp is especially favored inGermany and is… … Fig. 20.—The Hefner lamp. The Reichsanstalt lamp has been universally adopted as thestandard for the use of amyl acetate. The material of construc-tion is of brass except the wick-tube which is of German silver toprevent corrosion by the combustible. The wick is moved bymeans of a worm gear which…

Light · Photometry · Electric lighting

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