The _third_ and last point for our consideration in this connection is the emanation[305] and _mystery_ of colour in its entire effect. This witchery of colour appearance will mainly be found, where the substantive ideality of objects has become an effusion of spirit which enters into the scheme and treatment of its coloured presentment. In general, we may say that the magic consists in a handling of colour by means of which we obtain an interplay of scenic effect which is devoid of defined articulation as such, which is, in fact, simply the result of moulding of colour in the finest degree of fluency, a fusion of coloured material, an interplay of reflected points which pass into one another, and are so fine and evanescent in their gradations, so full of vital cohesion that the medium here seems already to have entered that of musical sound. From the point of view of modelling the mastery of chiaroscuro is part of this magic result, an aspect of the art in which among the Italians Leonardo da Vinci and, above all, Correggio were supreme. While introducing the very deepest shadow, the transparency of this is not only preserved, but is carried through imperceptible gradations to the most brilliant light. By this means roundness in the moulding of form is complete; there is no harshness of line or limit, but all is equable transition. Light and shadow are not here merely in their immediate effect as such, but gleam through one another much as a spiritual force is operative through an external shell. It is just an effect like this we find in the artistic treatment of colour, and the Dutch were no less than others consummate masters of this. By virtue of this ideality, this mutual relation between the parts, this interfusion of reflections and colour scintillations, this alternation and evanescence of transitional tones, a breath of soul and vitality is throughout communicated in the brilliancy, depth, the mild and juicy illumination of colour. It is this which gives us the magic effect of a masterpiece of colour; it is the unique gift of the genius of the artist who is himself the magician. (_γγ_) And this brings us to the last point we have to discuss on this part of our subject. We started with the _linear perspective_, we passed on then to _drawing_ and concluded with _colour_; _first_ considering light and shade in its relation to modelling, and, _secondly_, viewing it as colour simply, or more accurately, as the mutual relation between degrees of brightness and darkness in colours, regarding it, moreover, in its aspects of harmony, atmospheric perspective, flesh-colour and magical effect. We have now to consider more directly[306] the _creative impulse_ of the artist in bringing about such colour effects.