[Footnote 1:  See Fig. 1.]

[Illustration:  DETAIL; SHRINE OF THE THREE KINGS, COLOGNE]

The Shrine of the Three Kings in Cologne is decorated both with cloisonne and champleve enamels,—­an unusual circumstance.  In Aix la Chapelle the shrine of Charlemagne is extremely like it in some respects, but the only enamels are in champleve.  Good examples of translucent enamels in relief may be seen on several of the reliquaries at Aix la Chapelle.

Theophilus gives us directions for making a very ornate chalice with handles, richly embossed and ornamented with mello.  Another paragraph instructs us how to make a golden chalice decorated with precious stones and pearls.  It would be interesting as a modern problem, to follow minutely his directions, and to build the actual chalice described in the eleventh century.  To apply the gems and pearls Theophilus directs us to “cut pieces like straps,” which you “bend together to make small settings of them, by which the stones may be enclosed.”  These little settings, with their stones, are to be fixed with flour paste in their places and then warmed over the coals until they adhere.  This sounds a little risky, but we fancy he must have succeeded, and, indeed, it seems to have been the usual way of setting stones in the early centuries.  Filigree flowers are then to be added, and the whole soldered into place in a most primitive manner, banking the coals in the shape of a small furnace, so that the coals may lie thickly around the circumference, and when the solder “flows about as if undulating,” the artist is to sprinkle it quickly with water, and take it out of the fire.

Niello, with which the chalice of Theophilus is also to be enriched, stands in relation to the more beautiful art of enamel, as drawing does to painting, and it is well to consider it here.  Both the Romans and the Anglo-Saxons understood its use.  It has been employed as an art ever since the sixth and seventh centuries.  The term “niello” probably is an abbreviation of the Italian word “nigellus” (black); the art is that of inlaying an engraved surface with a black paste, which is thoroughly durable and hard as the metal itself in most cases, the only difference being in flexibility; if the metal plate is bent, the niello will crack and flake off.

[Illustration:  FINIGUERRA’S PAX, FLORENCE]

Niello is more than simply a drawing on metal.  That would come under the head of engraving.  A graver is used to cut out the design on the surface of the silver, which is simply a polished plane.  When the drawing has been thus incised, a black enamel, made of lead, lamp black, and other substances, is filled into the interstices, and rubbed in; when quite dry and hard, this is polished.  The result is a black enamel which is then fused into the silver, so that the whole is one surface, and the decoration becomes part of the original plate.  The process as described by Theophilus is as follows:  “Compose