We do not mechanically connect the sensation of white with the idea of light, any more than we connect the sensation of black with the idea of darkness. We admit that a black jewel, even if of a dead black, may be more luminous than the white or pink satin of its case. Loving light, we refuse to measure it, and we avoid the geometrical ideas of the focus and the ray, which imply the repetition-contrary to the principle of variety which guides us-of bright planes and sombre intervals in a given direction. Loving colour, we refuse to limit it, and subdued or dazzling, fresh or muddy, we accept all the possibilities contained between the two extreme points of the spectrum, between the cold and the warm tone.