counts are given by authors of the mode of preparing this pigment, the principal substance or colouring matter of which is a smoke black, having all the properties of our lamp-black; and the variety of its hues and texture seems wholly to depend upon the degree of burning and levigating it receives. The pigment known by the name Sepia is supposed to enter into the composition of the better sort.

XII. BLACK LEAD, Plumbago, or Graphite, is a native carburet of iron or oxide of carbon, found in many countries, but nowhere more abundantly, or so fine in quality, as at Borrodale in Cumberland, where there are mines of it, from which the best is obtained, and consumed in large quantity in the formation of crayons and the blacklead pencils of the shops, which are in universal use in writing, sketching, designing, and drawing; for which the facility with which it may be rubbed out by Indian rubber, caoutchouc, or gum elastic, and the crumb of bread, admirably adapts it.⁕

Although not acknowledged as a pigment, its

* Drawings, &c. in pencil are sometimes required to be fixed. This is best and most easily done with water-starch, prepared in the manner of the laundress, of such strength as just to form a jelly when cold, which may be then applied with a broad camel's-hair brush, as in varnishing. The same may be done with thin, cold isinglass size, or rice-water; but these contract and cockle.

powers in this respect claim a place for it, at least among water-colours; in which way, levigated in gum-water in the ordinary manner, it may be used effectually with rapidity and freedom in the shading and finishing of pencil drawings, &c., and as a substitute therein for Indian ink. Even in oil it may be useful occasionally, as it possesses remarkably the property of covering, forms very pure grey tints, dries quickly, injures no colour chemically, and endures for ever. These qualities render it the most eligible black for adding to white in minute quantity to preserve the neutrality of its

tint.

Although plumbago has usurped the name of Black Lead, there is another substance more properly entitled to this appellation, and which may also be safely employed in the same manner, and with like effects as a pigment. This substance is the Sulphuret of Lead, either prepared artificially, or as found native in the beautiful lead ore, or Galena, of Derbyshire.

CHAPTER XXII.

TABLES OF PIGMENTS.

As there are circumstances under which some pigments may very properly and safely be used, which under others might prove injurious or destructive to the work, the following Lists or Tables are subjoined, in which they are classed according to various general properties, as guides to a judicious selection. These Tables are the results of direct experiments and observation, and are composed, without regard to the common reputation or variable character of pigments, according to the real merits of the various specimens tried.

The powers of pigments therein adverted to might have been denoted by numbers; but since there is no exact and constant agreement in different specimens of like pigments, nor relatively among different pigments, it would have been an affectation of accuracy without utility: add to which, the properties and effects of pigments are much influenced by adventitious circumstances, and are sometimes varied or altogether changed by the grounds on which pigments are used, by the vehicles in which they are used, by the siccatives

Y

and colours with which they are used, and by the varnishes by which they are covered.

These Tables are therefore offered only as approximations to the true characters of pigments (some of which, for the above reasons, are liable to be disputed), and as general guides to right prac tice. They render it also apparent, as a general conclusion, that the majority of pigments have a mediocrity of qualification balancing their excellences with their defects, and that the number of good and eligible pigments overbalances those which ought in general to be rejected.

TABLE I.

Of Pigments, the colours of which suffer different degrees of change by the action of light, oxygen, and pure air; but are little, or not at all, affected by shade, sulphuretted hydrogen, damp, and foul air :

REMARKS. None of the pigments in this Table are eminent for permanence. No white or black pigment whatever belongs to this class, nor does any tertiary, and a few only of the original semineutrals. Most of those included in the list fade or become lighter by time, and also, in general, less bright.