which the painter blends his colours and forms his tints upon his palette, as was probably done by Titian and the Venetian school; and the other by which he makes as it were a palette of his picture, applying his colours unbroken, and producing his combinations therewith upon his canvas, as appears to have been the method of Rubens and Reynolds. To the first, a good eye is principally necessary; while the latter depends upon a better knowledge of colours,-it is also more favourable to the brilliancy, purity, and durability of colouring, according to the foregoing maxims. Here also the best practice is a compound of the two extreme methods, and in some measure essential to good colouring, and appears to have been acted upon in the landscapes of Gainsborough and Wilson.

The practice of producing tints and hues by grinding pigments together, instead of blending them on the palette, has fallen into disuse, whether advantageously or otherwise may be questioned; but to this disuse may be attributed some peculiarity of the tints and textures of the pictures of the Flemish school, they being perhaps results of intimate combination from grinding, and consequently of a more powerful chemical action among the ingredients compounded. It conduces also undoubtedly to that union upon which tone and mellowness depend, when the same pigments which lie near together in a picture are employed to form intermediate hues and tints; but this practice conducts to foulness when the colours of such pigments are not pure and true, and they do not assimilate well in mixture chemically.

We could not well avoid this digression on the modes of practice, upon which durability so much depends: for so concurrent is permanence with reputation, and so important is it, that had the sculpture of the Greeks been no more durable than their painting, literature could not have preserved the fame of their artists; and the reputation of their painters in our time is principally conceded to the transcendent excellence of their sculpture which still remains. Hence the modern artist, who is inattentive to the durability of his materials, may content himself with sharing some portion only of the reputation of the engraver, whose art will become to modern. times in this respect, what sculpture in relief has been to the antient; for as to colouring in particular, which has been called mechanical and subordinate, it is the only department of painting which cannot be copied and transferred mechanically by a copper-plate and a press, but requires a cultivated taste and judgment, a fine eye, and an able hand, united immediately in the work.

G

Abstractedly considered, it is probable that the durability of colour in substances is uniformly dependent upon the state in which they exist chemically or by constitution, with respect to what we have before regarded as the two concurrent and essential principles of light and colours, which we have distinguished by the terms oxygen and hydrogen; and this may account for the apparent capriciousness by which a pigment is found sometimes durable and sometimes not so, particularly the lakes, carmines, and most vegetal colours, the fugitiveness of which depends as much upon the state of their bases as upon the natural infirmity of their colouring matter. If the pigment or its base be in a state which the chemists have termed a protoxide, it will, by a gradual acquisition of oxygen from light, air, or moisture, change or fade, till being saturated, or becoming a peroxide, it is no farther subject to change by the election of oxygen.

On the other hand, pigments and bases assume similar states with respect to the hydrogenous principle of light, &c. in which they may be termed prothydrids and perhydrids, in which states they are subject to changes opposite but analogous to the preceding, and to this latter influence metallic colours and their bases are principally subject: upon the whole, however, oxygen being the more active of the two principles, colours are in a greater measure subject to its influence. Such is the subtile chemistry, in the simplest view we are able to take of it, upon which the changes of colours in pigments depend.

It would not be difficult to explain upon the same agency, why pigments are more subject to oxidation and fading in a water vehicle, and to hydrogenation and darkening in one of oil.

With respect also to permanence, it is worthy of remark, that recent pigments, both natural and artificial, like recent pictures, wines, &c. undergo amelioration by the influence of time, temperature, atmosphere, &c. which it is better they should suffer in the state of pigments than upon the canvas. Their drying in oil is in general also improved by age, and they approach nearer altogether to the condition of native pigments.

These effects of time, &c. are additional reasons for the esteem in which the colours as well as the works of celebrated deceased artists are commonly held; and this accords with the common remark, that time effects a mellow and harmonious change upon pictures; but sometimes it produces changes altogether unfavourable. To insure the former, and prevent these latter changes, the attention of the artist, in the course of his colouring, should be

directed to the employment of such colours and pigments as are prone to adapt themselves in changing to the intended key of his colouring and the right effect of his picture. For example, if he design a cool effect, ultramarine has a tendency through time to predominate, and to aid the natural key of blue: he will therefore compromise the permanence of his effect, if in such case he employ a declining or changeable blue, or if he introduce such reds and yellows as have a tendency to warmth or foxiness, by which the colouring of many pictures has been destroyed. In a glowing or warm key the case is in some measure reversed,-not wholly so, for it is observable that those pictures have best preserved their colouring and harmony in which the blue has been most lasting, by its counteracting the change of colour in the vehicle, and that suffusion of dusky yellow which time usually bestows upon pictures even of the best complexion.

Newly-discovered pigments, however flattering in appearance or in working, are to be employed with caution, or even suspicion, till experience has obtained them the stamp of excellence. Good pigments have ever been prized with so true an estimation of their value by all people, whether barbarian or refined, that it may be doubted if a really excellent one has ever been lost to the world; and to produce such after the ages of research which have passed, and for which all who have had eyes have been in a measure qualified, is, we may be assured, no ordinary result either of accident or design. Accordingly, most of the resplendent pigments, fruits of the fecundity of modern chemistry, have been found deficient of the intrinsic and sterling excellences which have given value and reputation to some of the antient and approved. Thus the splendid yellow chromates of lead, which withstand the action of the sunbeam, become by time, foul air, and the influence of other pigments, inferior even to the ochres. So again Indian yellow, which also powerfully resists the sun, is soon destroyed in oil, and changed by time, &c. Again, the vivid and dazzling reds of iodine are chameleon colours, subject to the most sudden and opposite changes, and yield the palm of excellence to the fine solid colours of vermilion, whose name they usurp and falsify. So again the brilliant blues of cobalt, beautiful and abundant as they are, which resist the sunbeam powerfully and have no present imperfection, are always tending to greenness and obscurity, and must yield their pretensions on the palette to the unrivalled excellences of ultramarine.

These, among the chief productions of modern chemistry, are valuable for the ordinary and temporary purposes of painting; but they captivate the eye by a meretricious beauty which misleads the judgment, and are to be introduced with great caution in the more elevated practice of the art.

As to the individual permanency or fugitiveness of pigments, we have noted them under their respective heads as they occur in the following chapters.

CHAP. VI.

ON THE GENERAL QUALITIES OF PIGMENTS.

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"Je voi bien," Damon dit, que vous voulez que le peintre ne laisse rien échapper de tout ce qui est de plus avantageux dans son art."-DU PILE, DIAL. p. 9.

HITHERTO We have treated of colour only, which is the universal quality of pigments, and of its relations, physical causes, and changes; there remain therefore for discussion the more material properties, upon which depend the various uses, excellences, and defects of pigments.

The general attributes of a perfect pigment are beauty of colour, comprehending pureness and richness, brilliancy and intensity, delicacy and depth,-truth of hue,-transparency or opacity, well-working, crispness, setting-up or keeping its place, and desiccation or drying well; to all which must be superadded durability when used, a quality to which the health and vitality of a picture belong, and is so essential, that all the others put together without it are of no esteem with the artist who merits reputation: we have therefore given it a previous distinct consideration.

No pigment possesses all these qualifications in perfection, for some are naturally at variance or opposed; nor is there any pigment that cannot boast excellence in one or more of them. BEAUTY, delicacy, purity, and brilliancy, are commonly allied in the same pigment, as are also depth, richness, and intensity in the beauty of others; and some pigments possess all these in considerable degree; yet delicacy and depth in the beauty of colours are at variance in the production of all pigments, so that perfect success in producing the one is attended with some degree of failure in the other, and when they are united it is with some sacrifice of both ;-they are the male and female in beauty of colour; the principle is universal, and the