The Persians, like the Greeks, mingled the natural with the conventional. Their vases and tiles (Fig. 13) are ornamented with floral designs, in which, while some of the flowers can be distinguished, others are altered beyond recognition. Among the Mussulman Persians the enamels reached the highest point of gorgeous brilliancy: glowing red as a ground-color, dishes with bottoms covered with rich arabesques--everything set in tints of the most pronounced and striking kind. Their decorations are many-hued as the rainbow; and if at times they lack its softly melting shades, they appear at others as if suspended in the clear and liquid glaze, as soft as the tints of early spring. White figures on a blue or yellow ground, or _vice versa_, are distinctive of much of the ornamentation of Persia. The mosque at Sultaneah (Fig. 14) is described as having its walls entirely “cased with enamelled tiles of deep blue, with yellow and white scrolls and devices.” The patterns are arabesque, occasionally mingled with animal and floral forms. The finest specimens of Persian tiling at the Museum at Sèvres are in blue and white, the latter forming the ground. [Illustration: Fig. 14.--Mosque at Sultaneah. Cased, inside and out, with enamelled tiles.] [Illustration: Fig. 15.--Japanese Porcelain. Cloudy gray, flecked with gold; dress, rose and gold. (Sutton Coll.)] These technical secrets, known centuries ago in Persia and the far East, have been coveted by ceramists down to the present day. They have been and are the most jealously guarded possessions of artists and factories, and history records many instances of the extreme precautions adopted to prevent their spread. The Japanese, for example, although indebted to China and Corea for the foundation of the knowledge upon which the magnificent structure of their subsequent art was built, guard with the utmost care the borrowed secrets in their possession. In a native work on porcelain it is said: “The painting and decoration of vases is a secret that it is not permitted to reveal.” Similar instances present themselves on every hand. The production of any unusually beautiful color, although really only one-half of the difficulty with which the ceramic artist has to contend, is universally regarded as a triumph. Such were the efforts upon which the potters of China expended their skill, and upon which the emperors of the Flowery Kingdom bestowed rewards. There are dynastic colors, but no dynastic style of ornamentation with design. The ability to apply color to an artistic creation was a secondary matter, and went without recognition. The position of the artist and the workman were thus in a measure inverted, if we insist that the production of color is mechanical, and its application artistic. If the decoration be examined, its execution in detail will be found to be almost perfect--birds of brilliant plumage, flowers of richest hue, men and women draped in Oriental splendor (Fig. 15).