MOSAIC. This term is applied to the art of composing figures in imitation of nature and painting, by the judicious ar rangement of fragments of marble and co loured glass, inserted in a composition, which, becoming hard soon after the ope ration is completed, renders the subject a durable.picture for ages. The learned are doubtful of the origin of the term, which is said by some to be derived from musaicum, which may be supposed to• convey an idea of an exceeding curious and difficult representation of natural ob jects in this way.
It is impossible to ascertain the ars of the invention ; but it is by no means im probable, that it was suggested by the forming of figures in pavements with dif ferent coloured stones or marbles, the durability of which substances, and their resistance of damps, suggested the intro duction of imitations of objects on walls and parts of buildings exposed to the ac tion of the weather ; those, however, probably were at first very rude and tasteless performances. The Greeks transmitted the art to the Romans : it was perpetuated in Italy, according to the Abbe Berthelemy, during the incur sions of the Barbarians, and brought to perfection in Rome in subsequent ages, where the works of the best masters still remain for the admiration of the present and many future generations. The frag ments, which are generally of marble, and cut into cubical forms, were distribu ted with great skill and judgment in the most impervious cement, and being thus firmly connected, the surface received a high polish. The elegance of the work consists in the true disposition of the fragments, their diminutive size, and the richness of the colours : of the latter, se veral of the principal were•obtained from the quarries of Sicily and Greece, " at the same time that the different shades were found blended in different species of marble. The whiteness and purity of snow was emulated by the Parian ; alabas ter, beautifully fair, by that from Synna da, in Phrygia ; and unsullied ivory, by a different description from Asia Minor ; the marble from Jassiis, in Canis, furnish. ed a glowing crimson ; and those of Si cily, granites and rubies." The interme diate colours and gradations of colours were supplied by several means, and par ticularly enamels, as appears from the mosaic works discovered in the Jesuits' college at Frescati, which were conveyed to the cabinet belonging to the order at Rome : in those the blue is a composition or paste • and in one of the pieces are two shades of yellow, one of which is marble, and the other brick.
There are specimens of ancient mosaic, composed exclusively of enamel, and sock were those which adorned the floors and walls of a house discovered in the last century at Surrento, and which are attributed to Pollio. Among the pieces
preserved at Rome, there were several that agreed with the ideas generally en tertained of this laborious and durable species of ornament : but far superior were those valuable fragments found by M. Furietti in Adrian's villa at Tivoli, which lie described in a work of great judgment and erudition. One of the pieces alluded to represents four doves, arranged on the rim of a vase, and is equally remarkable for the excellence of the performance, and the connection of the subject with another treated by Sosus, and taken from a house at Perp. Ms. " The Abbe, observes M. Furiet ti, is of opinion, that Adrian had caused it to be removed to embellish his house at Titoli ; but may we not as fairly pre sume, that the emperor was satisfied with a copy of it t An idea that would solve some difficulties found in the writings of The monument, however, most inte resting to antiquaries, was some years past preserved at the palace of the Princes of the Barbarini family at Pales trina, and is the celebrated work in mo saic, which, in its original destination, co vered the sanctuary of the temple at Pres, neste. This magnificent specimen of an cient skill is described by Berthelemy as being about eighteen feet in length, and rather more than fourteen in breadth, and the attributes of the hunters and animals represented on a mountainous country, in the upper part, left him no reason to doubt that the scene was intended for Egypt. Greek characters inscribed be neath the animals give their names. "In the lower part of the mosaic, we perceive the Nile, winding round several small islands ; boats with oars, or sails ; Egyp tians in pursuit of crocodiles, which con ceal themselves among the rushes ; rus tic cottages ; superb buildings; priests performing religious ceremonies in their temples ; Egyptian women, reclined un der a bower on the borders of a canal, with cups or musical instruments in their hands ; and, lastly, a magnificent tent, near which a general, followed by seve ral soldiers, armed with lances and shields, advances towards a female with a palm branch in her left hand, and in her right a species of garland, which she holds out to him. It was natural," adds this learned writer, "that the sagacity of antiquaries should be employed on so rich a compo sition. Father Kircher discovered in it the vissitudes of fortune ; Cardinal Po lignac, the arrival of Alexander in Egypt ; and Father Montfaucon, exhibitions of the Nile, of Egypt, and of Ethiopia." Bar. thelemy, with more probability, thought it represented the arrival of the Emperor Adrian in a province of Upper Egypt.