Let us build our walls, then, of stone, or brick, or stucco,--for their flat surfaces and neutral tints conduce to that repose so essential to good architectural effect: but let us not rest content with this, but grant to the eye the delight and contentment which it craves, by color and pattern placed at those points to which it is desirable to attract attention, for they serve the same æsthetic purpose as a tiara on the brow of beauty, or a ring on a delicate white hand. But just as jewelry is best when it is most individual, so the ornament of a building should be in keeping with its general character and complexion. A color scheme should not be chosen at random, but dictated by the prevailing tone and texture of the wall surfaces, with which it should harmonize as inevitably as the blossom of a bush with its prevailing tone of stems and foliage. In a building this prevailing tone will inevitably be either cold or warm, and the color scheme just as inevitably should be either cold or warm; that is, there should be a preponderance of cold colors over warm, or vice versa. Otherwise the eye will suffer just that order of uneasiness which comes from the contemplation of two equal masses, whereas it experiences satisfaction in proportionate unequals. Nothing will take the place of an instinctive colour-sense, but even that needs the training of experience, if the field be new, and a few general principles of all but universal application will not be amiss. First of all it should be remembered that the intensity of color should be carefully adjusted to its area. It is dangerous to try to use high, pure colors, unrelieved and uncontrasted, in large masses, but the brightest, strongest colors may be used with safety in units of sufficiently restricted size. For harmony, as well as for richness, the law of complementaries, in its most general application, is the safest of all guides, but it must be followed with fine discrimination. Complementary colors are like married pairs, if they find the right adjustment with one another they are happy--that is, there is an effect of beauty--but lacking such adjustment they are worse off together than apart. Every artist who experiments in color soon finds out for himself that instead of using two colors directly complementary, it is better to "split" one of them, that is, use instead of one of them two others, which combined will yield the color in question. For example, the color complementary to red is green-blue. Now green-blue is equidistant between yellow-green and blue-violet, so if for red and blue-green; red, yellow-green and blue-violet be substituted the combination loses its obviousness and a certain harshness without losing anything of its brilliance, or without departing from the optical law involved. Such a combination corresponds to a diminished triad in music.