"Parmi ies couleurs artificielles le peintre doit connoilre telle qui ont amitie; ensemble (pour ainsi dire), et celle qui ont antipathie; it en doit scavoir les valeurs separement, et par comparison des unes aux antres." - Du Pile: Dialogue, p. 6.

Having defined and exemplified colours generally, and discussed briefly their relations, causes, and general attributes, we proceed to the more particular and practical part of our work - the powers and properties of colours and pigments individually; a subject so pregnant with materials, and of such unlimited connexions - every substance in nature and art possessing colour, the first property of pigments - that volumes might easily be inflated to little purpose with a boundless catalogue of colouring substances, - with vague instructions to prepare bad colours, while good ones may be obtained at less expense - with the history of antient and modern colours, and with the biography, if we may use the term, of individual pigments; while our design is merely to sketch simply and briefly the characters and uses of those received into art, so as to bring the student to a knowledge of his materials by the shortest course: and this we purpose to do in the order suggested by their relations and the foregoing distribution, under their distinct heads.

In so doing we have introduced more illustrations of the poetic uses of colours than might appear necessary; because, in the absence of examples from paintings, or those of nature, they may serve to exercise and lead the mind into acquaintance with the expression and powers of colours in the abstract, and to fix them as impressions habitually on the mind of the artist by whose taste and feeling they are to be applied: at the same time we have rendered our quotations as brief as the sense would admit, which in many of the instances is of wider reference than could have been exhibited without swelling our illustration beyond reasonable hounds. Yet we would willingly call the attention of the student, in the widest reference possible, to the poet's art as a powerful auxiliary: antients and moderns have used it as such, and Homer may be considered not the patriarch of poets only, but of painters also. Plutarch remarks, " that poetry is an imitative art that hath in it much of the nature of painting;" and he observes, "that it is a common saying that poetry is vocal painting, and painting, silent poetry" The same may be asserted of colouring in particular.

• Works, Vol. iii. p. 46.

With regard to the beauty of colours individually, it is a general law of their relations, confirmed by nature and the impressions of sense, that those colours which lie nearest in nature to light have their greatest beauty in their lightest tints; and that those which lie similarly toward shade are most beautiful in their greatest depth or fulness, - a law which, of course, applies to black and white particularly. Thus the most beautiful yellow, like white, is that which is lightest and most vivid; blue is most beautiful when deep and rich, while red is of greatest beauty when of intermediate depth, or somewhat inclined to light, - and their compounds partake of these relations: we speak here only of the individual beauty of colours, and not of that relative beauty by which every tint, hue, and shade of colour becomes pleasing or otherwise according to space, place, and reference, for this belongs to the general nature and harmony of colours.

There is, however, a vicious predilection of some artists in favour of a particular colour, from which some of the best colourists have not been totally free, which arises nevertheless from organic defect or mental association; but these minions of prejudice are greatly to be guarded against by the colourist, who is every way surrounded by dangers: there is danger on the one hand lest he fall into whiteness or chalkiness; on the other, into blackness or gloom: in front, he may run into fire and foxiness, or he may slide backward into cold and leaden dulness: all these are extremes he must avoid. There are also other important prejudices to which the eye is liable, in regard to colours individually, which demand also his particular attention, because they arise from the false affections of the organ itself, to which the best eye is most subject: these are occasioned by the various specific powers of single colours acting on the eye according to their masses and the activity of light, or the length of time they are viewed, whereby vision becomes over - stimulated, unequally exhausted, and endued, even before it is fatigued, with a spectrum which clouds the colour itself, and gives a false brilliancy, by contrast, to surrounding hues, so as totally or partially to throw the eye off its balance and to mislead the judgment. This derangement of the organ may be caused by a powerful colour on the palette, a mass of drapery, the colour of a wall,* the light of the room, or other accidental circumstances; and the remedy against it is to refresh the eye with a new object - of nature, if possible - or to give it rest. The powers of colours in these respects will be hereafter adverted to under their distinct heads. As to the powers of pigments individually, and their reciprocal action and influence chemically, these will be denoted separately of each colour or pigment, and such colours as injure each other pointed out, leaving it to be understood that in instances not noticed colours may be mixed and employed with impunity.

* See Note I.

The attention of the artist to the individual powers of pigments, although it may be of less concern than the attention to general effect in colouring, is by no means less necessary in practice; and it has been well-remarked by Opie,* that he who would excel in colouring must study it in several points of view - in respect to the whole and in respect to the parts of a picture, in respect to mind and in respect to body, and in regard to itself alone; and without a knowledge of the powers of his pigments individually, he will be likely to fail in these other respects.

• Leet iv. p. 138.