The next mention occurs in the _T´ao lu_, which gives a short account of the wares under the heading _Kuang yao_, but beyond the statement that the industry originated at Yang-Chiang, it gives no information as to the date or circumstances of its commencement.[380] For the rest this account is very confused and unsatisfactory, and seems in part to refer to the porcelain decorated at Canton (see vol. ii., p. 211), or more probably to the Canton enamels. It is only in the last passage that we come into touch with a ware which is readily recognised as the familiar Canton stoneware. This is a hard-fired ware, usually dark brown at the base, but varying at times to pale yellowish grey and buff, with a thick smooth glaze distinguished from other ceramic glazes by its characteristic mottling and dappling. The colour is often blue, flecked and streaked with grey green or white over a substratum of olive brown, or again green with grey and blue mottling. At times the brown tints predominate, but the most prized varieties are those in which the general tone is blue. These were specially selected for imitation at the Imperial factories under T´ang Ying, and they are highly valued in Japan, where the ware in general goes by the name of _namako_.[381] In other specimens the glaze has a curdled appearance, and sometimes it seems to have boiled up like lava. The mottled glazes at times have a superficial resemblance to the dappled Chün wares, and there is no doubt that in recent times these imitative effects have been studied. The dating of the mottled Kuangtung wares, or Canton stonewares as they are commonly named, is always a difficult matter. They are still made and exported in large quantities, but it is certain that they go back at least to late Ming times. Sir Arthur Church exhibited a tray of this ware at the Burlington Fine Arts Club in 1910[382] which bore a date corresponding to 1625, and the name of the maker, Chin-shih. The glaze of this interesting piece is remarkably deep, rich and lustrous, and it may be regarded as typical of the finest period of the ware. The tray illustrated by Fig. 1 of Plate 48 closely resembles it in colour and quality. Stamped marks occasionally occur in these wares, the most frequent being the seals used by two potters, apparently brothers, named Ko Ming-hsiang and Ko Yüan-hsiang (see p. 221). It was formerly said that they lived at the end of the Ming period, but Dr. Bushell in his _Chinese Art_[383] reduced their antiquity to the reign of Ch´ien Lung (1736-1795). No reason is given for either of these dates, but their work is familiar, and as some of the examples have a decidedly modern aspect, I am strongly in favour of the later attribution. Plate 47 is a fine example of a Kuangtung glaze, in which the blue is conspicuous.[384] It is probably of seventeenth-century date.