Biscuit porcelain is specially suitable for figure modelling, because the sharpness of the details remains unobscured by glaze. It has been largely employed in European porcelain factories for this purpose, but the Chinese seem to have been prejudiced against this exclusive use of the material. As a rule they reserve it for the fleshy parts of their figures, giving the draperies a coating of glaze or of enamel or both. A rare example of the use of biscuit is illustrated in the catalogue of the Walters Collection (_O. C. A._, Plate XXIX.), a white bottle with a dragon carved out of the glaze and left in biscuit. The white wares so far described were made of the ordinary porcelain body and glaze, but there is another group of whites which is ranked with the so-called “soft pastes.” This is a creamy, opaque and often earthy-looking ware, the glaze of which is almost always crackled. It is in fact an imitation of the old Ting yao (q.v.), and its soft-looking surface and warm creamy tone are seen to perfection in small vases, snuff bottles, and ornamental wares. Indeed, the elegantly shaped and finely potted vessels of this soft, ivory crackle are among the gems of the period. Crackle is a feature which is common to many of the monochromes, and incidental mention has frequently been made of it in the preceding pages. It is essentially a Chinese phenomenon, dating back to the Sung dynasty, and there are various accounts of the methods employed to produce it. We are speaking of the intentional crackle which is clearly defined and usually accentuated by some colouring matter rubbed into the cracks, as opposed to the accidental crazing which appears sooner or later on most of the glazes of the _demi grand feu_, and on many low-fired enamels. One crackling process used by the Sung potters has been described on p. 99, vol. i. Another method is mentioned in the K’ang Hsi Encyclopædia,[366] viz. to heat the unglazed ware as much as possible in the sun, then plunge it into pure water. By this means a crackle was produced on the ware after the firing. But the normal process in the Ch’ing dynasty seems to have been to mix a certain ingredient with the glaze which produced a crackle when fired. There are constant references to this ingredient under the name of _sui yu_ (crackle glaze) in the letters of Père d’Entrecolles in connection with various monochromes, and in the first letter,[367] the following definite account appears:--“It is to be observed that when no other glaze but that composed of white pebbles[368] is added to the porcelain, the ware turns out to be of a special kind known as _tsoui ki_ (_sui ch’i_ = crackled ware). It is marbled all over and split up in every direction into a infinite number of veins. At a distance it might be taken for broken porcelain, all the fragments of which have remained in place. It is like mosaic work. The colour produced by this glaze is a slightly ashen white.”