The colour-sense: its origin and development : an essay in comparative psychology / by Grant Allen.

  • Grant Allen
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: The colour-sense: its origin and development : an essay in comparative psychology / by Grant Allen. Source: Wellcome Collection.

    37/304 (page 21)
    few Tiiore have such a diflcrent molecular arrangement as to absorb entirely, like soot, lampblack, and broadcloth. But most bodies have their molecules so set as to absorb certain amounts or orders of lether-waves and to return certain other amounts or orders. It is these last of which we generally speak as coloured objects. Practically speaking, black, white, and grey only differ in the amount of waves which they reflect and absorb, not in their kinds. A black object absorbs nearly all; a white object disperses nearly all; a grey object absorbs some and disperses some, but in nearly equal proportions of the various kinds. These varieties, then, yield us no sensa- tions of colour proper, but rather of light and shade. But many objects—the vast majority of objects, in fact—do not reflect the various constituents of the total wave-bundle in their entirety or in equal proportions. They have such a molecular constitution that they select from the waves which fall upon them certain special waves, whose frequency is the same as their own natural rate of oscillation, or else a multiple of the same. All others they reject and reflect back upon the aether with- out. It is these reflected waves which fall upon our eyes and yield us the sensation of colour. Very few natural objects, again, outside the organic class, yield us pure colours. Most of them are of dull mixed hues, like the various earths, sands, rocks, and clays. A very small and highly prized class of inorganic bodies do, indeed, reflect light of a single sort only, as in the ruby, the topaz, the amethyst, and other precious stones. But, as a rule, inorganic bodies, as found in nature, are dull browns, dingy greys, or muddy whites. AVhen we turn to the organic world, however, we find pure colours—that is to say, mther-waves of single or slightly compounded orders—very prevalent. In the green leaves of trees, the brilliant tints of flowers, the lovely hues of fruits, the wings of butterflies, the featliers of birds, we find colour constantly appearing in very pure