ART ENAMELS. Certain art produc tions beautified by decoration in enamel are termed by connoisseurs enamels. The enamel body is either translucent or opaque. It is composed of a frit or flux of lead glass. The lead ingredient has for its chief purpose the lowering of the melting point of the medium. This vitreous body, by the addition of metallic oxides, produces a colored translucent enamel. (See ENAMEL). It is rendered opaque by a proportion of bone-ash or of oxide of tin. Ground to a degree of extreme fineness this body is washed and moistened to the re quired consistency and then applied to the article to be decorated. It is then melted in a muffle oven and thereby adheres, in its fused condition, to the surface of the metallic back ground. The origin of the word enamel is its French synonym &tail. In most methods of art enameling the reverse side receives a coat of enamel; this so-called contre-email reduces the risk of the glassy decoration splitting or splintering off in the process of cooling.
Proofs lead to the supposition that the art of enamel decoration originated in the East. Any trace of the date of its discovery is lost, but the art dates very far back. The several different processes can be brought under the two heads: "Incrusted' (i.e., inlaid), such as champleve and cloisonné; and that superficially applied, the imaux peints, and the so-called ((Venetian* enamels. It had been quite gen erally supposed that the colored vitreous in lays in extant specimens of ancient Egyptian decoration were enamel work. Flinders-Petrie, however, declares they are inlaid pieces of glass and that the early Egyptians were not able to do enamel work on metal. But there are extant examples of Greek cloisonné enamels dating from the "finest Greek period* (about 400 a.c.). Brooches (fibulc•), and horse harness plates extant of Gallic origin show enamel work. Several vessels and pieces of personal adornment existing with enamel decoration appear to have been made some where between the 2d and 3d centuries A.D. In Ireland and England numerous wonderfully artistic and perfectly enameled ornaments have been dug up from the soil, proving that the Celts and Anglo-Saxons were experts in enamel decoration. Of such we have the Ardagh chalice, Tara brooch, King /Ethelwulf's sold ring, Ding jewel, brooches, pins, rings, armor, horse-harness plates, etc., in blue, ver milion, green, white enamel. These are in champleve work.
Cloisonne Enamels.— The process of cloisonné work is, briefly, the following: Wire is bent into curves and angles to form the outline of the design required. This wire net
work is soldered or otherwise fastened to the metal surface which is to form the base on which the decoration is to be applied. The different colored enamel powders are next used in filling in the open spaces or cells (cloisons). Then the piece is subjected to the muffle oven to fuse the enamel. When cooled the enamel is found to have melted down be low the level of the wire. Additional enamel is °charged" to fill the cells again, and the fusing process is repeated. This process of filling the cells and fusing is continued till the enamel, after fusion, is about level with the top of the wire. The surface of the piece is then filed off flat (termed stoned). If left with its natural surface after it is termed flushed. The surface is next given a friction polish. The early art of enameling in the West appears to have died out, but in the East (about the 7th century) the art was practised in Byzantium (ancient Constanti nople). It was cloisonné "work. Of this period (in Byzantine enamels) there is extant the °Iron Crown" of Lombardy at Monza. (See Caowxs). Of later dates are the "Paliotto" or San Ambrogio altar (835) by Volvinius in Milan (see ALTAR) made to the order of Archbishop Angilbert; the processional cross of Emperor Lotharius I (795-855) in the Cathedral of Aix-la-Chapelle. The votive crown in Saint Mark's, Venice (9th century), has enamel ornament. An enameled 'reliquary in Limburg (containing a piece of the Holy Cross) by its inscription informs us it was made to the order of Emperor Constantine VII (976). Gospel (Textus) covers of the 10th century of beautiful cloisonné decoration ex tant are several in Saint Mark's, Venice, one each in Saint Gall and Sienna. Some gold plates in the National Hungarian Museum, Pest, with their cloisonné pictures of the Em peror Konstantine IX, Monomachos and the Empress Theodora and Zoe are, probably, • parts of a crown, and date from 1042 and 1054. The Hungarian Stephan's crown (see CROWNS) has enameled plates in both arches and the circlet. The Pala d'Oro (see ALTAR) in Saint Mark's, Venice, was formerly an antependium and the enamel picture was made for Doge Pietro Orseolo I in Constantinople (976) and the added enamel plates were done for Doge Ordelafo Falieri (1105). Quite a large num ber of works were produced in Constantinople in Byzantine style for the European churches, such as reliquary caskets (chasses), crosses, book-covers, etc.; some show an inscription as proof. Under competition with the new champleve, Byzantine enamels disappear about the 12th century.