With respect to the case in which more colours than one are associated in the same petal or blossom, the difference of effect is extreme between a tasteful arrangement, or the reverse; and taste in this sense, that is, as far as it is subject to certain and invariable rules, comes properly within the scope of this essay. These rules, as before observed, may be classed under the heads of Combination and Contrast; for though the difference between these two modes of harmony may not seem so obvious as is implied in the opposition of the words, yet there is a real and essential opposition both in the principle of association and in the effect produced on the beholder. In either case there must be a mutual adaptation between the colours; but in the one, it is to form a single compound idea; in the other, two separate and rival ones.

Whether for combination or contrast, the colours must be in juxtaposition, but not necessarily in contact. Colours that do not readily combine may be seen to do so when there is an interval; and a contrast is often more striking when it is not only between the colours themselves, but between them as displayed in opposite parts of a flower. It is only requisite that the eye be able to take them in together.

1. The first mode of combination is that in which the two join and yet are completely distinct, as in two parallel stripes of the African Marigold; or in which one colour is laid on another, as in the spotted or blotched Calceolaria. For the effect of such an arrangement to be pleasing, there must be a positive agreement or a positive diversity between the colours: if the former, they will combine; if the latter, they will contrast. And the peculiar power of combination is seen in this, that whereas the strongest diversity produces the most striking contrast, in harmonious colours the most striking effect is sometimes when the diversity is least. Thus, in a collection of Pelargoniums, amongst the strong contrasts afforded by the maroon and other dark-coloured spots, a crimson, or still more a scarlet spot on a pink or orange ground, in which there is no contrast, and but little diversity, will be the surest to arrest and retain the eye. Some varieties of Iris, Ixia, and Gladiolus, are remarkable for blending harmonious tints; indeed the whole tribe of Irids and Amaryllids is as rich in every example of colour as the Orchids are in form.

2. Another mode of combination is that in which they become partially blended, and form a cloudy mass; which, if the constituents harmonise, gives the idea of richness, and is usually a mark of high quality. But if the cloudiness be only partial, it will run the risk of an appearance of mere unevenness of colour, which is a great fault; and if the constituents do not harmonise the result will be flat and dull.

3. The last form of combination is when they lose their separate existence, and produce an uniform new tint; in which case what has been said under the article of colour in general is applicable. Every existing colour may be considered as compound, because every known, or, indeed, conceivable one, may be made up of two others. And it is evident that the number of such must be unlimited; so that variety produced by colour must be unlimited likewise. And in nature we find it so. The various shades of colour in a self-Verbena give it as much variety as a party-coloured one has.

It seems hardly determinable with precision beforehand what colours will combine and what will not, or even what will contrast: except that, as might be expected, every colour will contrast with white or grey; and therefore it may be taken as a rule, that a small white or grey interval will reconcile any two colours. Their position on the solar spectrum conducts but a very little way, and is not to be implicitly trusted even so far as that. It is a deficiency, however, of no consequence; for even if it were otherwise, our only appeal would be to experience, and that is our guide now.

Yet thus far is plain, that in contrasts the most dissimilar elements, as those from opposite ends of the spectrum, or dark and light, or any other contraries, produce the greatest effect. And further, that colours which will not combine into one idea, will often readily harmonise without an interval, if by their position a contrast be excited. Thus the green-edged Auricula is considered the most perfect form of the flower, because the refractory green is made to contrast with the ring of colour by the rings being separated into parts of co-ordinate value by being concentric.

To conclude, then, if it be asked which is the higher origin of beauty, I would say, Contrast possesses the far greater range of effects, and has all the boldness, energy, and pungency on its side; but Combination presents all the smoothness, elegance, and high-toned richness of colouring, and, as far as I can analyse my own perceptions, excites the livelier emotions of pleasure. Contrast makes far more out of unpromising materials, and brings out their hidden and unsuspected powers, like pitting them in a contest of skill; to combination appertains refinement, and the grace peculiar to high breeding. Contrast, in short (to use a quaint similitude), has the virtues of democracy, combination those which may be called aristocratic.

It is by contrast that the margin of a large-blotched Pelargonium becomes so striking and effective, even when the beauty is enhanced, as it often is, by its being between colours that combine. There should, therefore, be no pencillings, nor any processes of the blotch breaking into it to mar its distinctness. It is by contrast that the white eye of others adds so much to their beauty. Neither of these properties has any positive value; it is relative, and depends on the contrast; and that in the throat is often formed entirely by the abruptness with which the colour terminates. Hence it is that a feather in the eye, however small, gives an. appearance of poverty, because it detracts from the purity of the white, and, by consequence, from the contrast in which the effectiveness resides.* Finally, it is to contrast, in a great measure, that the gorgeous splendour of the Tulip is owing; for its bold and bright colours being laid on the purest white or yellow surface, the extreme purity of the ground brings out with such perfect effect the strokes of the pencilling.