It requires no long disquisition to show that the dispositions which I have stated actually subsist in the human mind. Variety reanimates the attention, which is apt to languish under a continual sameness. Novelty makes a more forcible impression on the mind than can be made by the representation of what we have often seen before; and contrasts rouse the power of comparison by opposition. All this is obvious; but, on the other hand, it must be remembered, that the mind, though an active principle, has likewise a disposition to indolence; and though it loves exercise, loves it only to a certain degree, beyond which it is very unwilling to be led or driven; the pursuit, therefore, of novelty and variety may be carried to excess. When variety entirely destroys the pleasure proceeding from uniformity and repetition, and when novelty counteracts and shuts out the pleasure arising from old habits and customs, they oppose too much the indolence of our disposition; the mind, therefore, can bear with pleasure but a small portion of novelty at a time. The main part of the work must be in the mode to which we have been used. An affection to old habits and customs I take to be the predominant disposition of the mind, and novelty comes as an exception; where all is novelty, the attention, the exercise of the mind is too violent. Contrast, in the same manner, when it exceeds certain limits, is as disagreeable as a violent and perpetual opposition; it gives to the senses, in their progress, a more sudden change than they can bear with pleasure. It is then apparent, that those qualities, however they contribute to the perfection of Art, when kept within certain bounds, if they are carried to excess, become defects, and require correction: a work consequently will not proceed better and better as it is more varied; variety can never be the groundwork and principle of the performance--it must be only employed to recreate and relieve. To apply these general observations which belong equally to all arts, to ours in particular. In a composition, when the objects are scattered and divided into many equal parts, the eye is perplexed and fatigued, from not knowing where to find the principal action, or which is the principal figure; for where all are making equal pretensions to notice, all are in equal danger of neglect. The expression which is used very often on these occasions is, the piece wants repose; a word which perfectly expresses a relief of the mind from that state of hurry and anxiety which it suffers when looking at a work of this character. On the other hand, absolute unity--that is, a large work, consisting of one group or mass of light only--would be as defective as an heroic poem without episode, or any collateral incidents to recreate the mind with that variety which it always requires.