Light visible and invisible : a series of lectures delivered at the Royal Institution of Great Britain, at Christmas, 1896 (1897)
Thompson, Silvanus Phillips, 1851-1916, Royal Institution of Great Britain · New York : Macmillan · leaf 114
egion willbe less sensitive for red than it is for the other colours.Hence if gray {i.e. diluted white) is presented in view,the retina at the fatigued region is more sensitive toall the other tints present than it is to red, and willtherefore on the whole receive an impression in whichgreen… … FlG. 57- board. Diffuse daylight should be allowed to fall from the front upon the white card, making it gray. By lights suitably placed behind the coloured tissue is lit up. The eye therefore sees the gray ring between an inner and an outer circle of colour. And after looking for a very few…
Light · X-rays
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