Colour cannot stand alone; it cannot dispense with boundaries of some kind. [Footnote: Cf. A. Wallace Rimington. Colour music (OP. CIT.) where experiments are recounted with a colour organ, which gives symphonies of rapidly changing colour without boundaries--except the unavoidable ones of the white curtain on which the colours are reflected.--M.T.H.S.] A never-ending extent of red can only be seen in the mind; when the word red is heard, the colour is evoked without definite boundaries. If such are necessary they have deliberately to be imagined. But such red, as is seen by the mind and not by the eye, exercises at once a definite and an indefinite impression on the soul, and produces spiritual harmony. I say "indefinite," because in itself it has no suggestion of warmth or cold, such attributes having to be imagined for it afterwards, as modifications of the original "redness." I say "definite," because the spiritual harmony exists without any need for such subsequent attributes of warmth or cold. An analogous case is the sound of a trumpet which one hears when the word "trumpet" is pronounced. This sound is audible to the soul, without the distinctive character of a trumpet heard in the open air or in a room, played alone or with other instruments, in the hands of a postilion, a huntsman, a soldier, or a professional musician. But when red is presented in a material form (as in painting) it must possess (1) some definite shade of the many shades of red that exist and (2) a limited surface, divided off from the other colours, which are undoubtedly there. The first of these conditions (the subjective) is affected by the second (the objective), for the neighbouring colours affect the shade of red. This essential connection between colour and form brings us to the question of the influences of form on colour. Form alone, even though totally abstract and geometrical, has a power of inner suggestion. A triangle (without the accessory consideration of its being acute-or obtuse-angled or equilateral) has a spiritual value of its own. In connection with other forms, this value may be somewhat modified, but remains in quality the same. The case is similar with a circle, a square, or any conceivable geometrical figure. [Footnote: The angle at which the triangle stands, and whether it is stationary or moving, are of importance to its spiritual value. This fact is specially worthy of the painter's consideration.] As above, with the red, we have here a subjective substance in an objective shell. The mutual influence of form and colour now becomes clear. A yellow triangle, a blue circle, a green square, or a green triangle, a yellow circle, a blue square--all these are different and have different spiritual values.