BY M. CHEVREUL, MEMBER OF THE ACADEMT OF SCIENCES, PARIS.

Amongst the pleasures presented to us by the culture of flowering plants, there are few that exceed what we experience from the sight of a multitude of flowers varying in colour, form, and size, and in their arrangement upon the stem that supports them.

It is probably owing to the admiration bestowed individually upon each, and to the affection cherished toward them in consequence of the great care they have required, that pains have hitherto not been taken to arrange them in such a manner as to produce the best possible effect upon the eye, not only separately, but collectively. Nothing, therefore, is more common than a defect of proportion observed in the manner in which flowers of the same colour are made to recur in a garden. At one time, the eye sees nothing but blue or white; at another, it is dazzled by yellow, scattered around in profusion. The evil effect of a predominating colour may be further augmented where the flowers are of approximating but still different shades of colour. For instance, in the spring we meet with the Jonquil, of a brilliant yellow, side by side with the pale yellow of the Narcissus; in the autumn, the Indian Pink may be seen next to the China Hose and the Aster, and Dahlias of different reds grouped together, etc.

Approximations like these produce upon the eye of a person accustomed to judge of the effects of the contrast of colours, sensations that are quite as disagreeable as those experienced by the ear of the musician when struck by discordant sounds. The principal rule to be observed in the arrangement of flowers is, to place the blue next to the orange, and the violet next to the yellow, whilst red and pink blossoms are never seen to greater advantage than when surrounded by verdure and by white flowers; the latter may also be advantageously dispersed among groups formed of blue and orange, and of violet and yellow colours; for although a clump of white flowers may produce but little effect when seen apart, it cannot be denied that the same flowers must be considered as indispensable to the adornment of a garden, when they are seen suitably distributed amongst groups of flowers whose colours have been assorted according to the law of contrast. It will be observed by those who may be desirous of putting in practice the precepts we have been inculcating, that there are periods of the horticultural year when white flowers are not sufficiently multiplied by cultivation to enable us to derive the greatest possible advantage from the flora of our gardens.

Further, those plants whose flowers are to produce a contrast should be of the same size; and in many cases the colour of the sand or gravel composing the ground of the walks or beds of a garden may be made to conduce to the general effect.

In laying down the preceding rules, it is not meant to be asserted that a different arrangement of colours may not please the eye; but by adhering to the arrangement mentioned, we may always be certain of producing assemblages of colour conformable to good taste, whilst we should not be equally sure of success in pursuing a different course.

In reply to an objection that might be made, " that the green of the leaves, which serves, as it weie, for a ground for the flowers, destroys the effect of the contrast of the latter," we say, such is not the case; and to prove this, it is only necessary to fix on a screen of green silk two kinds of flowers, and to look at them at the distance of some ten paces. This admits of a very simple explanation; for as soon as the eye distinctly and simultaneously sees two colours, the attention is so riveted, that contiguous objects, especially when on a receding plane, and where they are of a sombre colour, and present themselves in a confused manner to the sight, produce but a very feeble impression.