Mosaic
2 of the 7 encyclopedias on this shelf carry an entry for Mosaic. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
mo-za'ik, a surface decorated by the fitting together of small bits of marble, gems, colored glass, or other substances, so as to form patterns. Mosaic is a Greek word meaning a small stone. The mosaics of the ancients rivaled paintings in refinement and delicacy. The earliest known specimens are small patterns appearing on jewelry, ivory fans, and similar articles. The Louvre and the British Museum possess some very fine mosaics from Nineveh and Egypt. Patterns of the lotus and the papyrus plant are inlaid in ivory with small bits of glass, lapis lazuli , and other gems. One exquisite bit of Egyptian work now in the British Museum is about three-eighths of an inch square. It was evidently a part of a ring. It is ornamented with the sacred hawk. Every feather on the bird's wing is produced in varying colors and tints by a number of stones so small that the use of a magnifying glass is required to tell them apart. The Greeks and Romans were famous for mosaic pavements. The bits of marble were ordinarily about a quarter of an inch in diameter. The walls of many buildings in Pompeii were faced with thin sheets and bits of marble, having the effect of paintings. Not infrequently the faces of statues were executed in mosaic. The Romans carried their mosaic work into England, in fact, into all parts of the Roman Empire. Much of the best work was done by Greek slaves in Roman employ. Mosaic work was used in the adornment of the early Christian churches. The artist from whom Michelangelo learned to paint was a master of mosaic, or marquetry, as it is sometimes called. An artist of that day boasted that he was able to produce 15,000 varieties of tints in mosaic work. A portrait of Pope Paul V contained 1,700,000 bits of glass, the largest no larger than a millet seed. It was the boast of the Italian masters of mosaic that they could imitate the finest paintings. To heighten the effects of their work they used gold and silver foil as a basis on which to build. They were able to imitate the transparency of the sky and water, to make a difference between the beard and hair of man, the fur and feathers of animals. They were able to form surfaces that had all the appearance of silk or woolen stuffs, and that, too, in any shade or color. The expression of faces, attitudes, spirited action, the charms of coloring; in short, everything possible to the artist in oils, seems to have been within the reach of the master of mosaic work. If the reader wonders how the workers in mosaic attained such power, it should be remembered that they were people of natural artistic ability, that they were intensely religious, and that they devoted themselves to their art from the earliest childhood. The time that young people nowadays spend in attending school they spent in working with their masters. See Painting
Collier's New Encyclopedia (1921)
a term applied to any work which exhibits a representation on a plane surface by the joining together of minute pieces of hard, colored substances, such as marble, glass, or natural stones united by cement (mastic), and serving as floors, walls, and the ornamental coverings of columns. Mosaic work is of Asiatic origin, and is probably referred to in Esther, ch. i: 6, about 519 b. c. It had attained to great excellence in Greece, in the time of Alexander and his successors. The Opus tesselatum was a tesselated geometrical pavement. Byzantine mosaics date from the 4th century A. D. The art was revived in Italy Tafi, Gaddi, Cimabue, and by Giotto, who designed mosaics, and introduced a higher style in the 13th century. In the 16th century Titian and Veronese also designed subjects for this art. The practice of copying paintings in mosaics came into vogue in the 17th century; and there is now a workshop in the Vatican. Modern Roman mosaic consists of pieces of artificial enamel, in place of natural stone. Italy at present leads in this art, and St. Peter's in Rome is remarkably rich in specimens of such work. In pyrotechnics, a device consisting of a surface with diamond-shaped compartments, formed by two series of parallel lines crossing each other. The effect is produced by placing at each intersection four jets of fire which run into the adjoining ones.