In number of colours, there is probably not much dif ference between the ancient and modern knowledge. The ancients seem to have been possessed of some colours of which we are ignorant, while they were themselves un acquainted with some of those more recently discovered. The practice of painters upon the revival of the arts, in making a secret of their preparation of colours, has been exceedingly prejudicial to this branch of the study, as the methods of painting were then as various as the artists. The improvements in chemistry have certainly in later times enriched painters with a profusion of tints, of which, in point of brilliancy at least, no combination of the primi tive colours known to the ancients could be capable. Some author, whose name we do not recollect, has taken the trouble to calculate the amount of tints which the com bination of the simple colours admit of ; we should cer tainly have pronounced them innumerable, had he not as certained eight hundred and nineteen to be the number of modifications. This, to a certain extent, must be fanciful, as the very nature of the thing forbids the establishing any rule of distinction, except the imperfection of the human eye, to carry the division any farther.
The colours enumerated by Pliny as in use among the ancients, amount to nine, 1st, Sinopis pontica, a sort of ochre ; 2d, Parxtonion, a white colour, found on the shores of Egypt; 3d, Purpurissum, a deep red ; 4th, Indicus color, a fine blue ; 5th, Armenium ; 6th, Cinnabar; 7th, 8th, Auripigmentum, a fine green ; and, 9th, Atramentum. This shows that the ancients were not ignorant of our principal colours, and might by combina tion have produced almost every tint. Many of their colours were so very highly priced, that it was customary for the person who commissioned the painting of a pic ture, to provide these particular colours, which were, 1st, Alinium ; and this, as appears by the paintings found in Herculaneum, they had of different degrees of intensity ; 2d, Armenium ; 3d, Cinnabar, of which they had two kinds, viz. the natural calx of mercury, and an artificial kind, prepared from a red species of sand found near Ephesus ; 4th, Chrysocolla ; 5th, Indicum ; the ancients were ignorant of the origin of this pigment, being sup plied with it from the east ; it appears to have been in digo ; and 6th, Purpurissum, a species of vermilion.
Of the encaustic mode of painting practised by the ancients, heat was the medium of application ; but our information on the subject is exceedingly limited, as no specimens of that kind have reached our day, and ancient writers seem not to have bestowed such attention to the arts, as to have induced any particular examination of the practices in use regarding it. According to what Pliny
says on the subject, it would appear that the colours mix ed with wax were made up into crayons, and melted as used on the picture, upon which the subject was pre viously traced with a metal point ; when the picture was finished, a waxen varnish was spread over all, in a melted state of course. By this means the colours obtained great brilliancy, and the work became protected from the injuries of the weather. After it was sufficiently dry, the surface was well polished. Various attempts have been made in modern times to revive this art, but as yet -with out perfect success. Indeed, the introduction of the more perfect system of oil painting, seems to supersede alto gether the occasion for its re-discovery, except to gratify antiquarian curiosity. The ancients made use of encaus tic painting in ornamenting their ships.
We have examples still preserved, of the ancient stucco, or fresco paintings, in the relics of Herculaneum, in which no particular is more remarkable than the very great ease of the flowing outline, which, though deeply marked, possesses all the spirit of a masterly sketch ; and in fact demonstrates, not only pure taste, but an uncom mon proficiency and elegance of touch. Many fine ex amples are preserved at Pompeii, besides what were dis covered in the ancient baths of Rome; the outline, which is deeply cut, is sometimes filled up, and sometimes not. The plaster was prepared with the very greatest care, for which various articles were selected, and laid on in dif ferent coats ; volcanic ashes, or terra pozzulana, was the first, and upon this a coat calcareous matter, finely prepar ed, followed. Their plaster was generally allowed to dry before the paint was applied, usually consisting of black, red, or white, if brilliancy was required, to serve as a ground colour. They mixed the colours with very strong glue. The arabesque paintings seem to have been the favourite subject of the ancient frescos, representing ca pricious compositions of every variety, and generally dis playing very great elegance and taste, as well as fertility of invention. They are exceedingly light and delicate; and, although painted on a plain ground, indicate, in the small details of buildings, and foreshortening of figures, no small knowledge of perspective. Raphael was much captivated by the merit of these ancient performances, and not only revived that mode of ornamental work, but made very great use of it, as his immortal works in the lodges of the Vatican testify.