On colour sense : an address delivered to the Biological Section of the British Association at Edinburgh on August 4, 1892 / by William Rutherford.

Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: On colour sense : an address delivered to the Biological Section of the British Association at Edinburgh on August 4, 1892 / by William Rutherford. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    shadow falls. We use an oxyhydrogen lantern, and transmit the light through plates of coloured glass care- fully selected. The experiment is rendered still more striking, though at the same time a little more complicated, by using two oxyhydrogen lamps, and throwing their light on the same portion of the screen. If a plate of coloured —say ruby—glass be held before one of the lamps, and an opaque object, such as the head of a T square, be placed in the path of both lights, the shadow cast by the white light falls on a surface illuminated by red light from the other lamp, and shows a deep red, far more saturated than the surrounding surface of the screen, where the red and white lights fall. The shadow cast by the red light shows the complementary bluish green, and the contrast of the two is exceedingly striking. When we use a plate of pure green glass, the shadow showing the inducing colour is a saturated green, the other shows the complementary purple. With yellow glass one shadow is deep yellow, the other pale blue. With blue glass one shadow is saturated blue, the other pale yellow. With pink glass the complementary green is deeper than the shadow showing the inducing pink, and is on that account very striking. These experiments which we have shown you point to some subtle physiological relation between comple- mentary colours. A colour-sensation produced in one part of the vision centre forces, so to speak, the neighbouring part, which is relatively quiescent, to pro- duce the complementary colour subjectively. I say vision-centre rather than retina, because, if one eye is