52 ON CERTAIN ANCIENT ENAMELS.

as well from their antii^uity as from the splendour and variety of their colours, and the material on which they have been generally executed. Any preliminary account of the origin of the art of enamelling on metal, or of the composition of the enamel, would be unnecessary after Mr. Way's excellent paper upon the subject in the Second volume of the Journal. It will be suflBcient for ni}^ purpose to notice, that from the commence- ment of the Christian era to about the thirteenth century, the enamelled work was formed exclusively by embedding the enamel in the metal, the metal divisions forming the general outlines of the pattern. In the thirteenth century appear plates of metal, generally silver or gold, covered with a delicate chiselHng in bas-relief, and clothed with colour by means of a coating of various transparent enamels through which the pattern is seen. And, lastly, in the fifteenth century, we find plates of metal, gold or copper, coated with a thick covering of enamel, on which the design is painted,^ In these successive processes, we perceive a tendency to the concealment and subordination of the metal that forms the groundwork of the enamel. At first the metal appears on the surface forming the principal lines of the pattern ; next we see it through a coloured medium ; and, lastly, it disappears altogether. This varied relation of the enamel to the metal on which it is fused, seems to supply distinctions available for the classification of the various products of the art. We hereby obtain the general divisions of them, into embedded enamel, enamel transparent on bas-relief, and ^Mm/^c? enamel.^ An accurate and scientific classification of the results of human ingenuity, is necessarily impossible, owing to the constant occurrence of combinations of various processes, and other exceptions to any rule. In the first of these divisions, where the enamel is embedded in the metal, considerable differences will be observed in the mode of working the metal itself. In some, the divisions are formed out of the solid metal, by tooling out the portions to be enamelled, so that the enamel is what may be termed ' I do not mean by this that one pro- division, incruste, when translated into cess ceased to be exercised when the other Enghsh, would apply equally to all ena- be^an, but simply to mark the period of mels. The name I have employed for the tlieir commencement. second class is naturally suggested by the 2 The classification employed by French term used by Cellini for this work, in antiquaries corresponds with that here which he excelled, — opera di hasao-rilievo. suggested ; but their name for the first