The typical _sang de bœuf_, or the ‘red of the sacrifice,’ as the Chinese call it, was that made under the _régime_ of Lang Ting-tso a forerunner of the three great directors of the imperial manufactory at King-te-chen, and in later times it was always the aim of the potter to imitate his work--the Lang yao--even in trifling details. According to the Père D’Entrecolles, to obtain this red the Chinese made use of a finely granulated copper which they obtained from the silver refiners, and which therefore probably contained silver. Some other very remarkable substances, he tells us, entered into the composition, but of these it is the less necessary to speak, as he confesses that great secrecy was maintained on the subject. In looking carefully _into_ a glaze of this kind, the deep colouring-matter is seen suspended in a more or less greenish or yellowish transparent matrix, in the form of streaks and clots of a nearly opaque material.[93] The hue, in general effect, varies from a deep blood-red to various shades of orange and brown, but intimately mixed with the red, certain bluish streaks are sometimes to be seen in one part or another of the surface. The colours should stop evenly at the rim and at the base, which parts, if this is achieved, are covered with a transparent glaze of pale greenish or yellowish tint. We have already seen that much depends upon the period of the firing at which the glaze becomes liquid or soft, and upon the exact degree of fluidity attained by it. Should the oxidising currents be allowed further play at the critical period of the firing, the blue and greenish stains and splashes will become more predominant, and we may either pass over to the _flambé_ or ‘transmutation’ glazes, or finally the glaze may become almost white and transparent. But we must hark back to the wares of the Sung period, to the Chün yao, to find the origin of these variegated glazes. These early Sung glazes were copied in the time of Yung-cheng, and if we are to believe the contemporary list, already quoted, of the objects copied, they were of a very complicated nature. In this class of _flambé_ ware we must include also a large part of the so-called _Yuan tsu_ (see p. 77), a heavy kaolinic stoneware, certainly not all dating from the Yuan or Mongol period--a ware, indeed, still common in the north of China. This ware is roughly covered with a glaze of predominant lavender tint, speckled with red, and thus approaches to the ‘robin’s egg’ glaze of the American collector, though this latter is found on a finer porcelain of later times.