[10] We can, however, distinguish, in the tomb paintings of the Middle Empire, an earlier form without the lower table. This earlier type, moved by hand from the upper table, was that used by the Greeks at least as late as the sixth century B.C., and a similar primitive wheel is still used in India. On later Egyptian monuments of Ptolemaic time, the potter is seen moving the wheel by pressing his foot on a second lower table, as now at Sèvres and elsewhere. Both forms of wheel appear to have been used by the Italian potters of the Renaissance. [11] This seam is often visible on vases of old Chinese porcelain, and may be taken as a sign that the object has been moulded. [12] Porcelain in China followed, as we shall see, in the wake of the more early developed arts of the bronze-caster and the jade-carver. Hence the prevalence in the early wares of shapes unsuitable to the wheel. [13] I think that this is a more practical division than the one made by M. Vogt and adopted by Dr. Bushell. [14] An important exception is to be noted in the case of the firing of large vases in China. [15] A good instance of the first case is the finding of crow-claws in the rubbish-heaps of Fostât or Old Cairo. As to the method of support indicating the place of origin, see what is said below about the celadon ware of Siam. [16] There is only one exception of any importance--the porcelain of Chantilly, much of which has an opaque stanniferous glaze. [17] So we can infer from the magnificent wall decoration of the Achæmenian period brought home from Susa by M. Dieulafoi. [18] A glaze of this nature was in the Saracenic East applied to a layer of fine white slip, which itself formed a coating on the coarse paste. Such a combination, often very difficult to distinguish from a tin enamel, we find on the wall-tiles of Persia and Damascus. [19] Metallic gold has, of course, been applied to the decoration of porcelain in all countries. [20] The colour of the ruby glass in our thirteenth century windows has a very similar origin. In this case the art was lost and only in a measure recovered at a later period. As in the case of the Chinese glaze, the point was to seize the moment when the copper was first reduced and, in a minute state of division, was suspended in floccular masses in the glass. [21] With these colours a dark blue is sometimes associated. Is this derived like the turquoise from copper? It is a curious fact that we have here exactly the same range of colours that we find in the little glass bottles of Phœnician or Egyptian origin, with zig-zag patterns (1500-400 B.C.). [22] See Vogt, _La Porcelaine_, p. 219. The problem is really more complicated. For simplicity’s sake we have ignored the changes that take place in the glaze that lies between the enamels and the paste. [23] The same result may be obtained by painting one colour over the other, as we find in the black ground of the _famille verte_.