DECORATION WITH SLIP.--There is a class of ware which might perhaps claim a separate division for itself--I mean that decorated with an _engobe_ or slip. We have already mentioned the most important cases where this _engobe_ is applied to the surface of single-glazed wares: these are, in the first place, the _fond laque_ (PL. XVI.), and in a less degree certain blue and even white wares. The slip, of a cream-like consistency, is as a rule painted on with a brush over the glaze, generally, I think, after a preliminary firing.[95] This _engobe_ may then itself be decorated with colours, as we have seen in the case of the Ko yao, and the whole surface probably then covered with a second glaze.[96] Sometimes when the ground itself is nearly white we get an effect like the _bianco sopra bianco_ of Italian majolica. This carefully prepared and finely ground _engobe_ contains, in some cases at least, the same materials as those employed in the preparation of the Sha-tai or ‘sand-bodied’ porcelain. PIERCED OR OPEN-WORK DECORATION (PL. XVIII. 1).--We may here find place for another kind of decoration, one much admired in Europe in the eighteenth century. [Illustration: _PLATE XVIII._ 1--CHINESE, PIERCED WARE, BLUE AND WHITE 2--CHINESE, BLUE AND WHITE WARE] This is obtained by piercing the paste so as to form an open-work design, generally some simple diapered or key pattern, but sometimes flowers or figures of cranes. The little apertures or windows thus formed may be filled in by the glaze (if this is sufficiently viscous to stretch across them) in the simple process of dipping. In this case the glaze takes in part the place of the paste, and indeed in the closely allied ‘Gombroon’ ware of Persia it is the thick, viscous glaze rather than the friable sandy paste that holds the vessel together. It is the plain white ware to which this decoration is generally applied in China. There is one class where this pierced work is associated with groups of little figures, in biscuit, in high or full relief--as is well illustrated by a series of small cups in the Salting collection, some of which bear traces of gilding and colours. The term ‘rice-grain’ was originally applied to the open-work diapers filled in with glaze. As a whole this kind of work may be referred to the later part of the reign of Kien-lung, and especially to that of his successor, Kia-king (1795-1820), so that it is not unlikely that the Persian frit-ware, some of which is of earlier date, may have served as a model. BLUE AND WHITE WARE.--This is, on the whole, the most important as well as the best defined class of Chinese porcelain. The Chinese name, _Ching hua pai ti_ (literally ‘blue flowers white ground‘), defines its nature well enough.