THE MANUFACTURE OF MOSAICS AND IMITATION INLAID OR INTARSIA SURFACES.
THIS beautiful method of cementing various kinds of stones, This beautiful method of cementing various kinds of stones, glass, etc., seems to have originated in Persia, whence it found its way into Greece in the time of Alexander, and into Rome about 170 B. C. The critics are divided as to the origin and reason of the name. Some derive it from mosaicum, a corrup tion of musaicum, or, as it was called among the Romans, mu sivum. Scaliger derives it from the Greek Morisa, and imagines the name was given to this sort of work by reason of its ingen uity and exquisite delicacy. Nebricensis is of the opinion it was so called because " ex illis picturis ornabantur musea." Mosaic work of glass is used principally for the ornamentation and decoration of sacred edifices. Some of the finest speci mens of this work are to be seen in the Church of the Invalides at Paris, in which is the tomb of Napoleon I., and in the fine chapel at Versailles. Mosaic work in marble is used for pavements of churches, basilicas and palaces ; and in the incrustation and veneering of the walls of the same structures. As for that of precious stones, it seems to be used only for ornaments for altar pieces and tables for rich cabinets.
The mosaic manufacture at the present day in Rome is one of the most extensive and profitable of the fine arts. Workmen are constantly employed in copying paintings for altar pieces, though the works of the first masters are fast moldering away on the walls of forgotten churches. The French, at Milan, appear to have set the example by copying in mosaic the " Lord's Supper " of Leonardo da Vinci; but their plan was to do much for Milan and nothing for Rome, and consequently a great many invaluable frescoes of Michael Angelo, Raphael, Domenichino and Guido were left to perish. It takes about seven or eight years to finish a mosaic copy of a painting of the ordinary historical size, two men being con stantly occupied in the work. The time and expense are, of
course, regulated by the intricacy of the subject and quantity of the work. Raphael's " Transfiguration " took nine years to complete, ten men constantly working at it.
The execution of some of the latter's work is, however, con sidered very inferior. The slab upon which the mosaic is made is generally of travertin (or tiburtin) stones, connected together by iron clamps. Upon the surface of this a mastic, or cement ing paste, is gradually spread, as the progress of the work re quires it, which forms the adhesive ground, or bed, upon which the mosaic is laid. The mastic is composed of fine lime from burnt marble, and finely powdered travertin stone, mixed to the consistence of a paste with linseed Oil, Into this paste are fixed the " smalts," of which the mosaic picture is formed. They are a mixed species of opaque, vitrified glass, partaking of the nature of stone and glass, and composed of a variety of minerals and materials, colored for the most part with different metallic oxides.
Of these, no fewer than 1,700 different shades are in use. They are manufactured in Rome, in the form of long slender rods, like wires, of various degrees of thickness, and are cut into pieces of the requisite sizes, from the smallest pin point to an inch. When the picture is completely finished, and the cement thoroughly dried, it is highly polished. Mosaic, though an ancient art, is not merely a revived, but an improved one. The Romans only used colored marbles at first, or natural stones, in its composition, which admitted of little variety; but the invention of " smalts" has given it a wider range, and made the imitation of painting far closer. The mosaic work at Flor ence is totally different from this, being merely inlaying in " pietre dure," or natural ornamental or precious stones, of every variety, which form beautiful and very costly imitations of shells, flowers, figures, etc., but bears no similitude to painting.