In my former letters I have been occupied in the comparatively easy task of criticising the objections made by others. I now come to the more hazardous one of building up a system myself, and giving the objectors an opportunity of treating me as I have treated them; and, in truth, I invite, or rather request, them to do so. That there is a scientific system at the bottom of the ordinary estimates of flowers, I have long been convinced; and if I do not succeed in developing it, the fault will be in these papers, which, therefore, I should wish to be found fault with, because there is now an ample sufficiency of facts accumulated for the science of floriculture to be thence ascertained, and to take its place with other established systems. It is time for some one to do it, if I should fail.

I proceed, therefore, to point out more particularly my view of the scientific principles on which the general agreement among florists, in what should be considered points of excellence in their flowers, is based. After which, I purpose to apply those principles to some of the flowers, as a specimen of what is required in all for an acknowledged standard, to be referred to both by growers and judges; premising, however, that I have not the arrogance to propose this essay as such a standard: nor could it be; for the principles themselves must first be sifted by criticism, both friendly and unfriendly, until some principles are established and recognised, and not till then can such a manual be compiled. But this may serve as a first attempt towards it, - to attract others into the same path, in order to weed out what is unsound, to prune what is amiss, and to supply what is wanting. It will also serve to shew that there are defined and certain boundaries, within which are confined respectively the province of science, within which there will always be agreement, and the province of taste, which admits of infinite diversity.

And I am pleased at seeing the increase of instances of persons conversant with the details of such matters, and who probably have not turned their attention to the modes by which their judgments have been influenced, feeling their way intelligibly and successfully to the very points which reasoning will demonstrate to be the true points of ideal excellence. Mr. Kendall has, in a recent Number of The Florist, given us the properties of a good Cineraria; and, as far as he has gone, if he had studied Aristotle and the metaplrysicians, he could not have done it better. His guide probably was the experience of a practised and interested eye. It will be the province of these essays to shew by reason that he is right in every particular.

The end proposed by the Creator in the arrangement and colours of the petals of a flower is that which is pleasant to the eye; and the two means by which this is produced are form and colour.

Form is available in two respects - absolute, or direct, which is sought for its own sake; in that some forms are in their nature more pleasing than others, as a curve is more graceful than a straight line, and some curves than others: and relative, or indirect, which is subsidiary to some other purpose; in that some forms are better suited than others to set off colours to advantage, as a smooth petal exhibits its markings more perfectly than a wrinkled one can.

Colour is simply for its own sake; but it produces its effect in two ways - by contrast, as in painting, light appears to be thrown upon any point by placing a shadow beside it; and by combination, as purple unites harmoniously with either of its constituent elements, red or blue, while green will hardly unite with any other. Combination moreover may take place in three ways: where each is preserved, as when one colour shades off imperceptibly into another; where distinctness begins to be lost by partial fusion, as in the clouded colours; and where the separate elements blend into an uniform new tint, as in the endless diversity of compound colours.

These are the few and elementary principles on which, with the latitude to be allowed for tastes, which will be defined hereafter, depends the effect of any flower in pleasing the eye. And it will be found that these principles are strictly scientific, and reducible to rules capable of application to each species of flower, so as to determine, in a great and ascertainable measure, the value of any variety of each species.

And, in fact, it is because there is so much of scientific rule, founded in nature, in the pursuits of florists, that there has been that large amount of agreement among them, which we find to have obtained in a matter which is vulgarly believed to be a mere matter of individual taste and caprice.

Form or shape is the figure contained by a limiting outline. And it is the outline which for the most part suggests to the mind the idea represented by the figure, as has been demonstrated by Retsch in his celebrated illustrations of the German and English poets.

An outline may be either general, of the whole flower under consideration, as the cup of a Tulip; or subordinate, as being contained with others within the general outline, as that of the blotch in the petal of a Pelargonium. This distinction it is necessary to enlarge upon, because, in judging of excellences or defects, what in the former would be a fault, in the latter would be a beauty. The two kinds of outline having different offices to fulfil, require different properties for their perfection.

For subordinate outlines being always appended to, and controlled by, the leading idea of the whole flower, admit, with manifest advantage, departures from perfect forms, which would be intolerable in the general one. Thus the eye of a Pansy, if clear and not confused, is striking in proportion as it is made up of bold dashes and abrupt contrasts, presenting an uneven outline, which, if found in the flower which contains the eye, would condemn it to the dunghill.

These and other similar instances, presenting at first a difficulty to reconcile them with rule and reduce them to order, are, in fact, no exceptions. They are examples of what our experience in every thing is full of, that as in the material world every particle of matter is under the influence of an infinity of attractions on every side, the amount of each of which is nevertheless subject to an invariable law, and therefore the inclination of the particle towards any is reducible to the strictest scientific investigation; so, in the intellectual world, what are commonly supposed to be exceptions, are, in reality, only instances of the things coming within the superior influence of some other rule. Every rule is paramount in its own little circle; but that circle is in every case very small, because there are other rules on the subject which have an equal claim to be obeyed in their place, the interfering influences of which must have their due weight allowed to them.

It is a great mistake, and dishonourable to God as well as to ourselves, indolently to rest satisfied with calling so many things "exceptions," as we are in the habit of doing. An exception is, for the most part, only an expression of our ignorance. Real exceptions are much rarer than they are supposed to be. Our minds were made for order; and however our habits may seem to contradict the assertion, it is still a fact bearing evidence of our high original and destination that disorder is unnatural to us. And this may be seen, not only in the natural preference always in the long-run shewn for scientifically perfect forms, but also in the mode in which we unconsciously form our judgments of them. Thus, in examining a flower, we may not be aware of the fact, but it is not the less true, that we proceed according to strict rule and method. First, we obtain a leading idea, excited by the whole, as made up of and containing its parts. Next, we begin to separate those parts into their respective groups; and as our examination is extended or repeated, subdividing those again into their more elementary units.

And as we become more familiar, and better acquainted with the object of examination, this process is reviewed and altered, and the divisions and subdivisions recast into other groupings arising out of, or suggesting, new and other ideas. So that we may often perceive, as we contemplate a flower, new ideas and associations arising in our minds, and actually, as it were, changing its appearance in our eyes, and altering our judgment of it. Hence an extended familiarity with any flower is necessary before its characteristic points will be discovered, and its most natural divisions and peculiarities definitively settled. But when this process has been sufficiently gone through, the judgment will in most cases be found to be in accordance with nature, and will be generally acquiesced in.

And a much earlier and more perfect agreement may be expected when the natural principles, in accordance with which our preferences are formed, are known and understood.

There is, then, always one leading idea suggested by any flower, controlled by the general outline of its form, and the disposition of its principal parts. This is the characteristic of the flower, to which all its other properties must be subservient. It is not always easy to express in words what this idea is, though when there is some other thing with which we are familiar to serve as an illustration, there is no difficulty. Thus the idea of a Tulip is a painted cup, and that of a Dahlia or a Ranunculus is a variegated rosette.

And as the general outline takes the lead in the impression produced by the flower, a defective form in it cannot be compensated, because there is nothing of equal value, by a counter-excellence, in which it might be balanced. If, therefore, that outline be not full and graceful, the flower must needs be faulty. Such is the native Pansy, and therefore its improvement depended on first bringing its general form into what it may now be said to have obtained, a near resemblance to a circle. The Cineraria is still defective in this, from its outline consisting of points. And therefore its improvement, on the supposition of its continuing a single flower, first demands the rounding off of its petals. Whether it would be improved if rendered double is a question, on the solution of which something will be said when treating of the principle of variety. And thus much in the outset concerning outlines, general and subordinate.

[To be continued.] IOTA.