Black and white have already been discussed in general terms. More particularly speaking, white, although often considered as no colour (a theory largely due to the Impressionists, who saw no white in nature as a symbol of a world from which all colour as a definite attribute has disappeared). [Footnote: Van Gogh, in his letters, asks whether he may not paint a white wall dead white. This question offers no difficulty to the non-representative artist who is concerned only with the inner harmony of colour. But to the impressionist-realist it seems a bold liberty to take with nature. To him it seems as outrageous as his own change from brown shadows to blue seemed to his contemporaries. Van Gogh's question marks a transition from Impressionism to an art of spiritual harmony, as the coming of the blue shadow marked a transition from academism to Impressionism. (Cf. The Letters of Vincent van Gogh. Constable, London.)] This world is too far above us for its harmony to touch our souls. A great silence, like an impenetrable wall, shrouds its life from our understanding. White, therefore, has this harmony of silence, which works upon us negatively, like many pauses in music that break temporarily the melody. It is not a dead silence, but one pregnant with possibilities. White has the appeal of the nothingness that is before birth, of the world in the ice age. A totally dead silence, on the other hand, a silence with no possibilities, has the inner harmony of black. In music it is represented by one of those profound and final pauses, after which any continuation of the melody seems the dawn of another world. Black is something burnt out, like the ashes of a funeral pyre, something motionless like a corpse. The silence of black is the silence of death. Outwardly black is the colour with least harmony of all, a kind of neutral background against which the minutest shades of other colours stand clearly forward. It differs from white in this also, for with white nearly every colour is in discord, or even mute altogether. [Footnote: E.g. vermilion rings dull and muddy against white, but against black with clear strength. Light yellow against white is weak, against black pure and brilliant.] Not without reason is white taken as symbolizing joy and spotless purity, and black grief and death. A blend of black and white produces gray which, as has been said, is silent and motionless, being composed of two inactive colours, its restfulness having none of the potential activity of green. A similar gray is produced by a mixture of green and red, a spiritual blend of passivity and glowing warmth. [Footnote: Gray = immobility and rest. Delacroix sought to express rest by a mixture of green and red (cf. Signac, sup. cit.).] The unbounded warmth of red has not the irresponsible appeal of yellow, but rings inwardly with a determined and powerful intensity. It glows in itself, maturely, and does not distribute its vigour aimlessly (see Fig. 2).