Let us then consider for a moment what the materials were that the Chinese had to draw from--whether from Arab or other sources.
Putting aside the application of stained glass to windows, for specimens of this art are not easily exported, these may be summed up as, first, the enamelled glass of the Saracens, and secondly, the _cloisonnés_ and _champlevés_ enamels of the Byzantines and other Western nations.
As to the first--the application of coloured and easily fusible enamels to the surface of glass, which was then exposed to a second firing--this process had been used by the Arabs for the decoration of their mosque lamps and other vessels probably as early as the twelfth century, and this was an art identical in its system with the application of the same colours to the surface of porcelain. The beauty of the effect cannot have failed to have struck the Chinese if they had had any opportunity of seeing the finer specimens. But the material was fragile, and apart from a statement by M. Scherer that glass was exported from Aleppo to China,[44] I cannot find in the accounts of the Arab trade of the time any record of such ware being imported into China.
On the other hand, we know that enamels on metal are first mentioned in the Ming annals about the middle of the fifteenth century. They take their name of Cheng-tai enamels from the emperor who reigned at that period; but the proper Chinese term for such enamels is _Folang chien yao_--‘the inlaid ware of Folang.’ Julien interpreted these words ‘_Porcelaines à incrustations (ornées d’émaux) de France_,’ and Dr. Hirth carries us to Bethlehem! But the word _Folang_ is probably the same as the term _Folin_ or _Fulen_, used as early as the sixth century for the Roman empire of the East, and it may possibly be connected with the Greek πόλις (cf. Stamboul = Εἰς τὴν πόλιν).[45] It is definitely stated by a later Chinese writer that the same colours are employed by both the enameller on metal and the decorator of porcelain.
If we examine the colours found on both the wares to which we have tentatively traced back the enamelled porcelain of the Chinese--the enamels on glass on the one hand, and those on metal on the other--taking in each case the earlier specimens as examples, we find on the mosque lamps from Cairo little except a deep blue generally used as a ground for a design which is outlined in an opaque iron red. On the famous flask from Würzburg, now in the British Museum, for which a ‘Mesopotamian’ origin of the thirteenth century is claimed, a turquoise blue relieved by gilding is the predominant note; there is also a sparing use of yellow, of an opaque white, and, what is especially interesting, of a fine pinkish red, which is possibly obtained from gold. (The way in which this colour is shaded into the opaque white reminds us of the similar use of the _rouge d’or_ in later times in China.)