History relates many instances of the jealousy of sovereigns with regard to the quality of red. Surrounding accompaniments of this colour have always a grave and magnificent effect. 798. The red glass exhibits a bright landscape in so dreadful a hue as to inspire sentiments of awe. 799. Kermes and cochineal, the two materials chiefly employed in dyeing to produce this colour, incline more or less to the _plus_ or _minus_ state, and may be made to pass and repass the culminating point by the action of acids and alkalis: it is to be observed that the French arrest their operations on the active side, as is proved by the French scarlet, which inclines to yellow. The Italians, on the other hand, remain on the passive side, for their scarlet has a tinge of blue. 800. By means of a similar alkaline treatment, the so-called crimson is produced; a colour which the French must be particularly prejudiced against, since they employ the expressions--"Sot en cramoisi, méchant en cramoisi," to mark the extreme of the silly and the reprehensible. GREEN. 801. If yellow and blue, which we consider as the most fundamental and simple colours, are united as they first appear, in the first state of their action, the colour which we call green is the result. 802. The eye experiences a distinctly grateful impression from this colour. If the two elementary colours are mixed in perfect equality so that neither predominates, the eye and the mind repose on the result of this junction as upon a simple colour. The beholder has neither the wish nor the power to imagine a state beyond it. Hence for rooms to live in constantly, the green colour is most generally selected. COMPLETENESS AND HARMONY. 803. We have hitherto assumed, for the sake of clearer explanation, that the eye can be compelled to assimilate or identify itself with a single colour; but this can only be possible for an instant. 804. For when we find ourselves surrounded by a given colour which excites its corresponding sensation on the eye, and compels us by its presence to remain in a state identical with it, this state is soon found to be forced, and the organ unwillingly remains in it. 805. When the eye sees a colour it is immediately excited, and it is its nature, spontaneously and of necessity, at once to produce another, which with the original colour comprehends the whole chromatic scale. A single colour excites, by a specific sensation, the tendency to universality. 806. To experience this completeness, to satisfy itself, the eye seeks for a colourless space next every hue in order to produce the complemental hue upon it. 807. In this resides the fundamental law of all harmony of colours, of which every one may convince himself by making himself accurately acquainted with the experiments which we have described in the chapter on the physiological colours. 808.