The principles of art, including especially those of delineation, although all originating and deducible from nature, as will more particularly and at large be pointed out in one of the following sections, are nevertheless best to be enunciated by the examination of those works of art in which the application of these principles has been peculiarly successful. Those persons who are of the most penetrating genius, alone can abstract these principles from the performances themselves. And the more numerous are the models which]} any one has before him from which to form his own principles, the more rich and varied will be his store. This is the real and only true value of experience. In each of these works he may find some excellence to imitate, or some defect to shun, and may trace both alike to the observance or neglect of the particular rule of art on which they are dependent. Unless certain settled principles are established, there can be no satisfactory criterion by which to decide on the merits of works of art. It is, how-ever, on every account, of the utmost consequence that these principles should be sure and determinate in their formation, and free from caprice as regards their application.
For the carrying out of these principles, certain elements are essential, which form the materials on which the operation of these principles must proceed. In the accomplishment of delineation, they are not only absolutely necessary, but the efficiency of these principles depends upon the proper and due use of these elements.
The elements employed in artistical effort, whether of delineation or the production of picturesque effect, may be severally distinguished and classified as regards both their nature and operation, into the following order 1.) Elements which are active, being those which produce the result at which they are aiming, by some active operation in the constitution of the combination itself, as regards the subject or object to be represented. (2.) Those which are merely and entirely passive, although no less effective, in the accomplishment of the same end. (3.) Those which may be termed originating, inasmuch as, of them-selves, they originate and introduce some entirely original principle or feature into the combination, so as to give it a new and distinct character by this means alone. (4.) Those which are merely derivative, owing their efficient and peculiar character to their connection with certain other elements or subjects, which communicate to them their force and efficiency. (5.) Those elements which exist and are independent of themselves, both as regards their effect and their operation in the combination, without reference to any other object or element, and which by themselves alone produce important results. (6.) Those elements which have no force or effect when applied or acting by themselves alone, but which owe all their force and effect to their relation, and to their being auxiliary to other elements or subjects upon which they operate, or which they affect, or which are operated upon and affected by them. Other elements are (7) direct, operating directly and obviously in the promotion of the end they have in view ; while others are (8) indirect, operating only in an indirect and collateral manner. (9.) Some elements are of themselves absolutely essential and indispensable to complete the combination, which, without their presence, loses all its force and effect, and are consequently always to be found there ; while others are (10) dispensable, however useful and efficient, not being essential for, or always found united in the combination.
Although the elements themselves are in all respects the same whether they exist independently or have relation to each other ; yet this relation or connection, while it does not in the least degree change or affect their essential nature, entirely alters their mode of operation, and also that of affecting us, which is in reality the most important position in which to view them. The elements of gunpowder are not in any respect, or in any degree, actually changed by being mixed together ; but this commixture is, nevertheless, what gives to each, and to the whole compound, the power that it possesses.
The various elements which contribute to produce any particular effect or result, whether in the way of delineation or of picturesque effect, although, like the arts in general, they may be very different in their nature and mode of action, ought all to conduce to the attainment of the same result, even should they act separately in a very opposite manner. Thus, one element may serve to set the mind or the feelings at work. Another to correct and constrain, and indeed counteract the operation to which some other element would lead. Certain elements are auxiliary only to the operation of particular elements ; while some of themselves originate operations which it is left to others to direct to their appointed and legitimate result.
As regards both the elements of delineation and those of the picturesque, it is essential that at least several of them together be availed of in conjunction, and not merely one or two only, the effect of which will be rather to lessen than to heighten the effect aimed at. It is not necessary to include all; but it is requisite that a certain number should be combined in every effective artistical design.
It must be acknowledged, moreover, that in certain cases of this kind, as in analogous instances of classification in nature, there may occasionally be considerable difficulty, and a question may fairly arise, whether a particular element may not claim to belong as much to the picturesque as to delineation, or to de-lineation as to the picturesque. Sometimes, indeed, it cannot be denied that to a greater or less extent it is auxiliary to both. I have, however, done my best to classify correctly these several elements, and must leave it to the candour of the critics to condemn what I have done ; or, what is more important, to correct me where I am in error.
Certain other elements of a delineative nature might also be specified; but which, as they only relate to particular branches of art exclusively, are not strictly admissible here. Such are light and shade, and colour and perspective (incidentally touched upon in subsequent parts of this chapter) * in painting; metre in poetry, punctuation in eloquence, and other principles of this order, which are each applicable only to their own proper and particular art; and which, moreover, belong rather to the mechanical and manual, than to the mental branch of the subject.