The pieces of which mosaic work were originally formed were very large, and sometimes gilded and silvered. About the close of the third century, a Floren tine, named Andrea Tasai, contemporary with Cimabne, the restorer of the art of painting, introduced an improved manner of executing it, which soon attracted the attention of the rich and powerful, and in consequence mosaic paintings became much more common than they had been for a long time before. Tasai, however, does not deserve the sole merit of reviv ing the art, as he acquired his skill from Apollonius, a Greek, who had performed several very fine pieces for St. Mark's church at Venice.
A few specimens of the gilded man ner of executing figures in mosaic may still be seen in England, and particularly in Westminster Abbey, where the tombs of Edward the Confessor and.of Henry III. have been adorned in this way in fan ciful figures, some of which are perfect, but the greater part are destroyed by the billy practice of picking out the frag ments of glass, to discover what may be seen on each side—the mode of setting them in the cement. " How much," says Keysler, " this curious art has been im proved, during the two last centuries, may be easily seen, by comparing the coarse works in some of the old cupolas of the chapels in St. Peter's church with the other pieces lately erected there. The
studs in these old works are made of clay burnt, and the surface only tinctured with various colours." Another description of mosaic work has been made by the moderns, in the following manner. That wholly of mar ble is done by preparing a piece of the same material, either white or black. The artist having traced the design upon this plane, he excavates or cuts it with a chi sel, perhaps to the depth of an inch : other pieces of the colour necessary for the parts are then shaped as correctly as possible to fit the excavations, and set in them with cement. Thus far completed, the artist finishes the shading by drawing intersecting lines with a pencil, and those being cut into the design as before, they are filled with a black composition, partly consisting of Burgundy pitch, which when rubbed off and rendered smooth by polishing, affords an imperfect picture, very greatly inferior to the beautiful works produced in the manner before described, and rather deserving the term of inlaid work than mosaic. There arc other methods of imitating this splendid production of art ; but with materials that precept a possibility of deception ; indeed their poverty of effect has ope rated to banish them from the palaces of Europe almost universally. •