Colour measurement and mixture. Published under the direction of the Committee of General Literature and Education appointed by the Society for Promoting Christian Knowledge (1891)
Abney, William de Wiveleslie, Sir, 1843-1920, Society for Promoting Christian Knowledge (Great Britain). General Literature Committee · London: Society for promoting Christian knowledge; New York, E. & J. B. Young & co. · leaf 116
reeslits can be placed in any part of the spectrum, COLOUR MEASUREMENT AND MIXTURE. 113 and that they can be narrowed or widened atpleasure. Instead of a card the writer uses ametal slide, as shown in Fig. 30. It will be seen that the three slits can be closedor opened from the centre by a parallel… … Fig. 30.—Slide with slits to be used in the Spectrum. grooves in which the slits move are another pair ofgrooves, into which small pieces of card CCCCcan slide, and thus close the apertures between theslits. By this arrangement all rays except thosecoming through the slits themselves are cut off.…
Color
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