Measurement of light and colour sensations : a new method of investigating the phenomena of light and colour by means of the selective absorption in coloured glass, graded into scales of equivalent colour value
Lovibond, Joseph W. (Joseph Williams), 1835-1918, George Gill and Sons, publisher · London : George Gill and Sons, Minerva House, Warwick Lane, E.C. · leaf 18
a taper partition, b, terminating in a knife edge at the eyepiece c, the aperture of which it divides into two equal parts. This cell is represented crosswise in aperture. At the other end are two openings, a, A, which admit two equal but separate beams of light to the eyepiece in such a manner,…
Color · Light · Optics
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