Mosaic

MOSAIC, either a method, or the result produced by a method, of forming a surface by placing close together small pieces of marble, glass, tile, enamel, etc., usually for decorative effect. Mosaic is an outgrowth of inlay. In early periods of culture, small carvings of wood, stone or ivory were often decorated by inserting into them minute pieces of brilliant stone or enamel. When the area of such inlays is greater than the exposed area of the original material, which thus becomes merely a base and frame to hold the pieces of inlay, the result may be called mosaic. Many examples have been found in Egypt and Mesopotamia, dating from early cultural periods and chiefly ornamenting jewellery, furniture, small tablets and the like. The Egyptians had a certain grasp of larger possibilities for the material, as excavations at Tel el-Yehudia in lower. Egypt have revealed. Examples of column capitals and wall tiles show decorative richness where bits of coloured glass and earthenware have been inserted into sinkages in the tile or stone to form lotus and other ornaments. Recent dis coveries in the Mesopotamian valley prove that the Sumerians had, at least as early as c. 3500 B.C., taken the next logical step in mosaic design and glued or cemented the small pieces of coloured stones to a base. A remarkable work in lapis lazuli and pink sand stone, excavated at Ur by the joint expedition of the British Museum and the University of Pennsylvania, is probably a stand ard, showing on one side an army going to battle, and on the other, a king or noble at a feast. This, probably dating from c. 3500 B.C., had the lapis lazuli and sandstone fastened to a wood background with bituminous cement. (See Illustrated London News, p. 1176, June 23, 1928.) The Egyptians of the later empire apparently abandoned the use of mosaic except for jewellery, but in this they developed the amazingly skilful technique in glass mosaic, which is still employed in north Italy in making mosaic jewellery. This consisted of the use of small rods of coloured glass put together in such a way that their ends formed the desired pattern. The bundle thus made was heated, and so, partially fused together, drawn out while still hot to many times its original length so that at the centre, its section was but a small fraction of its original size. The whole was sliced, each slice giving a miniature reproduction of the original pattern. Thus, results of microscopic delicacy were pro duced, and the well known Egyptian skill produced coloured glass of great brilliance and variety ; the most common colour was a greenish blue, widely used as a background.

Greek and Roman.

It is probable that the Greeks of the pre-Alexandrian period had developed at least the rudiments of mosaic technique, but it was only in the late Hellenistic era that this type of decoration became common. The name opus Alexan drinum (applied to one type, and its invention sometimes wrongly attributed to the emperor Severus Alexander), undoubtedly points to Alexandria as the great centre for work of this type. Few ex amples in Greece proper can be dated earlier than the Roman occu pation. The House of the Trident of Delos shows exquisite ex amples of late Hellenistic mosaic. It is also a fact that in Pompeii, many of the finest examples of floor mosaics, such as the famous Battle of Issus, from the House of the Faun, date from as early as the 2nd century B.C. ; and even the subject of this, unquestionably the most effective of ancient picture mosaics, with its representa tion of Alexander the Great, would seem to point to a Hellenistic origin and a Greek artist. In all of these early floor mosaics, the main body of colour is formed by tesserae, or small cubes, of care fully selected coloured marbles, but occasional bits of glass and tile are sometimes present.

Such large pictorial mosaics as the Battle of Issus in intricately worked detail, were exceptional in Roman floor mosaic work. Usually pictorial features were merely incidental panels in a much larger scheme of floor decoration, a type of design both more practical, and decoratively more satisfactory. Various types can be traced in the hundreds of examples of Roman floor mosaics pre served, not only in Italy, but in Syria, north Africa, France, Germany and England. The simplest, which from its common oc currence in even the most modest houses in Pompeii indicates an extremely inexpensive method of floor covering, consisted of an all-over simple geometric pattern, of two colours only. The tes serae of the background were of many shapes and sizes, put in almost at random, so that the effect approximated that of ter razzo (a cement coating embodying an aggregate of small pieces of coloured marbles, highly polished). The second class consisted of those in which a simple, central, rectangular field, usually light in colour, was surrounded by a decorative border of greater or less richness. These borders comprised some of the most effective mosaic designs of the time. In colour they were usually simple, often merely black and white.