It is on this blue ware that the greater number of the Chinese characters are found denoting the period in which the porcelain was made. The cobalt on the earlier pieces was not so fine as on those of the _Siouen-te_ and _Ching-hoa_ periods, which are now much sought after. It is extremely difficult to tell even the approximate date of the coloured pieces, especially as there was a conventional method of decorating them which had been practised from time immemorial; the painters worked according to given models or patterns, and monsters, deities, or flowers and landscapes, of the same uncouth and rude designs, were placed in successive ages upon the ware. [Illustration: FIG. 328.--PORCELAIN VASE. _Painted in enamel colours._] The Père d'Entrecolles tells us the manner of painting vases in China, and how the different parts of a landscape on one vase were intrusted to various hands according to their ability to paint special objects mechanically. He says: "One is employed solely to form the coloured circle which is seen round the border of the ware, a second traces the flowers in outline, which a third fills in with colour; another excels only in painting the water and the mountains, while the next is only competent to portray birds or animals." [Illustration: FIG. 329.--PORCELAIN EWER. _Painted in enamel colours, and mounted with Florentine copper gilt. 17th century._] A sort of very hard stoneware, covered with a thick glaze, may be the most ancient description seen at the present day. The surface is covered with a semi-opaque glaze which is called _céladon_ by the French, and which varies in colour from a russet grey to a sea green. The glaze of this ware is frequently seen crackled all over in irregular lines, which is termed in England _crackle_. This crackle china is the most esteemed of Oriental porcelain, although it arises from a _defective_ cause. [Illustration: FIG. 330.--BOTTLE. _Powder blue porcelain. Ming dynasty._] [Illustration: FIG. 331.--JAR. _Painted with plum blossoms. Ming dynasty._]