"Chiefly under the direction of one man, it would seem that the produce of the Gubbio furnaces was for the most part of a special nature; namely, a decoration of the pieces with the lustre-pigments, producing those brilliant metallic-ruby, golden, and opalescent tints which vary in every piece, and which assume almost every color of the rainbow as they reflect the light directed at varying angles upon their surface. That the Gubbio ware was of a special nature, and produced only at a few fabriques almost exclusively devoted to that class of decoration, is to be reasonably inferred from Piccolpasso's statement, who, speaking of the application of the maiolica-pigments, says, '_Non ch'io ne abbia mai fatto ne men veduto fare._' He was the maestro of an important botega at Castel-Durante, one of the largest and most productive of the Umbrian manufactories, within a few miles, also, of those of Urbino, with which he must have been intimately acquainted and in frequent correspondence. That he, in the middle of the sixteenth century, when all these works were at the highest period of their development, should be able to state that he had not only never applied or even witnessed the process of application of these lustrous enrichments, is, we think, a convincing proof that they were never adopted at either of those seats of the manufacture of enameled pottery. Although much modified and improved, lustre-colors were not invented by Italian artists, but were derived from the potters of the East, probably from the Moors of Sicily, of Spain, or of Majorca. Hence (we once more repeat) the name 'majolica' was originally applied only to wares having the lustre enrichment; but, since the decline of the manufacture, the term has been more generally given: all varieties of Italian enameled pottery being usually, though wrongly, known as 'maiolica.' "That some of these early _bacili_, so well known, and apparently the work of one artist, were made at Pesaro, whence the secret and probably the artist passed to Gubbio, is far from improbable. The reason for this emigration is not known, but it may be surmised that the large quantity of broom and other brush-wood necessary for the reducing process of the reverberatory furnace in which this lustre was produced might have been more abundantly supplied by the hills of Gubbio than in the vicinity of the larger city on the coast. That the process of producing these metallic effects was costly, we gather from Piccolpasso's statement that sometimes not more than six pieces out of a hundred succeeded in the firing.