The _first_ point we have to deal with here is the _brightness_ and _obscurity_ of particular colours respectively to one another, that is in so far as they are operative as light and dark in their varied relations, and either emphasize or suppress and impair their individual effect. Red, for example, and still more yellow, is at an equal grade of intensity more brilliant than blue. This is dependent upon the nature of the colours themselves, which in recent times Goethe has for the first time fully explained[286]. In other words, we find that in blue _shadow_ is of main significance, which, in its first operation through a brighter, but not as yet fully transparent medium, appears to our sight as blue. The sky, for example, is dark, and on the highest mountains it is yet darker. Seen through a transparent but thick medium, such as the atmosphere of its lower planes is, it appears as blue, and its brightness increases in proportion as the air is less transparent. In the case of yellow, on the contrary, essential brightness works through a density, which, however, suffers this brightness to shine through it. Smoke, for example, is such an obscuring medium; looked at in front of anything black which works its way through it, it appears of a bluish tint, and before anything bright it appears yellow and reddish. Genuine red is the actively royal and concrete colour, in which blue and yellow, themselves also extremes of opposition, press together in fusion, We may also regard green as such a union, not, however, in a unity that is concrete, but merely as a difference that is cancelled, as a medium of satiated and tranquillized neutrality[287]. These colours are the purest, simplest, and original _cardinal_ colours. We may consequently find a symbolical significance in the way that the old masters made use of them. Especially is this so in their use of blue and red. Blue corresponds with the milder, sensuous, more tranquil aspect, a contemplation which is rich in feeling, in so far as it has obscurity for its principle, and offers no resistance, whereas the brightness therein rather suggests that which resists, produces, is alive and blithesome. Red corresponds with what is masculine, dominant, and royal, green with that which is indifferent and neutral. According to such symbolism for example, the Virgin Mary is frequently clothed in red where she is enthroned, and set before us as queen of heaven; where she is depicted as mother, she wears a blue mantle[288]. All the other colours in their endless variety must be regarded as mere modifications of the above, in which we must recognize a certain degree of shadow fused with the cardinal colours. In this sense no painter would call violet a colour[289]. Furthermore all these colours, in their mutual relation to each other, are respectively of greater brightness or obscurity, a fact that the artist must bear in mind if he is not to fail in