Among the assortments of two luminous colours, there are scarcely any besides those of red and orange with which grey associates more happily than white. But it is inferior to it, as also to black, in the arrangements red and green, red and yellow, orange and yellow, orange and green, yellow and green. It is also inferior to white, with yellow and blue. 245. 9th. _Grey, in combining with sombre colours, such as Blue and Violet, and with broken tones of luminous colours, produces harmonies of analogy, which have not the vigour of those with black; although the colours do not combine well together, it has the advantage of separating them from each other._ 246. 10th. _When Grey is associated with two colours, one of which is luminous the other sombre, it will perhaps be more advantageous than White, if this produces too strong a contrast of tone; on the other hand, it may be more advantageous than Black, if that increases too much the proportion of sombre colours._ _Examples._ Grey associates better than Black with— 1. Orange and Violet. 2. Green and Blue. 3. Green and Violet. 247. 11th. If, when two colours accord badly, there is in principle an advantage in separating them by White, Black, or Grey, it is important to the effect to take into consideration—1. The height of tone of the colours. 2. The proportion of sombre to luminous colours, including, in the first, the broken brown tone of the brilliant scales, and in the luminous colours, the light tones of the Blue and Violet scales. Consider the height of tone of the colours. 248. The effect of white with red and orange is inferior as their tones become higher, especially in the assortment white, red, orange, white, &c.; the effects of the white being too crude. On the contrary, black unites very well with the normal tones of the same colours, that is to say, the highest tones without any mixture of black. Although grey does not associate so well as black with red and orange, it has the advantage of producing a less crude effect than white. Consider the proportion of sombre to luminous colours. 249. Whenever colours differ very much, either in tone or in brilliancy, from the black or white with which we wish to associate them, that arrangement where each of the two colours is separated from the other by black or white, is preferable to that in which the black or the white separate each pair of colours. Thus the assortment white, blue, white, violet, white, &c., is preferable to the assortment white, blue, violet, white, &c., because the separation of the brilliant from the sombre is more equal in the first than in the second. I should add that this is somewhat more symmetrical as to the position of the two colours, and the principle of symmetry influences our judgment of things more than is generally recognised. It is also in conformity with the above, that the assortment black, red, black, orange, black, &c., is preferable to the assortment black, red, orange, black, &c.