. Physical researches on sensation [by] Frank Allen [and others]. hromatics, 3rd Ed., p. 257. Oct., 1924] Kkklex of Color C(»ntk.\st 377 eye a mixture of red with white light, wliiili will give the observer theidea that he is looking at a horizontal, square field of a somewhat palereddish tint. If now a small black square be attached to the verticalcardboard at B, of course no white light can come to the eye from thisportion of the cardboard and the image of this spot will seem to the eyeto be at h on the horizontal board under the eye. Inder ordinary cir-cumstances this image would ai)
. Physical researches on sensation [by] Frank Allen [and others]. hromatics, 3rd Ed., p. 257. Oct., 1924] Kkklex of Color C(»ntk.\st 377 eye a mixture of red with white light, wliiili will give the observer theidea that he is looking at a horizontal, square field of a somewhat palereddish tint. If now a small black square be attached to the verticalcardboard at B, of course no white light can come to the eye from thisportion of the cardboard and the image of this spot will seem to the eyeto be at h on the horizontal board under the eye. Inder ordinary cir-cumstances this image would ai)pear black; in point of fact, however,in this case it a])pears deep red. owing to the red light transmitted bythe plate of glass. Jhus far the arrangement amounts Ut a device forpresenting to the eye a mixture of red with white light, the white lightbeing absent at a certain spot, which aj)pears of a deeperred. A similar black square is mnv to be placed on the horizontal boardat (; it will of course prevent the light from the place it covers from. tlG. 1. C onlfifl tthtiud oj Ka^i lui Siina. reaching either the red glass or the eye. and under ordinary circum-stances would be i>erceive(l simply as a square black siH)t to the fact that the upper surface of the glass plate is reflect-ing white light to the eye. it really appears :us a grey spot. The finalresult is that we present to the eye at K a pale-red ground on which isa spot of pure grey, and near it (»ne which is deej) red. Owing to con-trast, however, the aj^pearance is dilTerent: instead of a grey .spot, wesee one strongly coloured green-blue. This ellect is partly due to con-trast with the palc-retl of the ground, but still more to the presence ofthe deep red sj^ot. Ihis latter we can remove by taking away the blacksquare. B, which diminishes the elTect considerably. Hut now comes themost curious part of this experiment; if we select a square of grey paperwhich has the same colour with t
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectphysiol, bookyear1902
