The one exception mentioned above is the type represented by the “barrel-shaped seats.” The description of these leaves no room for doubt that they belonged to a fairly familiar class of Ming ware, whose strength and solidity has preserved it in considerable quantity where the more delicate porcelains have disappeared. Plate 62 gives a good idea of the Ming barrel-shaped garden seat, “with solid ground filled in with colours in engraved floral designs.” The other kind, “with openwork ground, the designs filled in with colours (_wu ts’ai_), gorgeous as cloud brocades,” must have been in the style of Plate 61. These styles of decoration are more familiar to us on potiche-shaped wine jars and high-shouldered vases than on garden seats, but the type is one and the same. Quite a series of these vessels was exhibited at the Burlington Fine Arts Club in 1910, and they are fully described in the catalogue. Some had an outer casing in openwork; others had the designs outlined in raised threads of clay, which contained the colours like the ribbons of cloisonné enamel[40]; in others, again, the patterns were incised with a point. The common feature of all of them was that the details of the pattern were defined by some emphatic method of outlining which served at the same time to limit the flow of the colours. The colours themselves consist of glazes containing a considerable proportion of lead, and tinted in the usual fashion with metallic oxides. They include a deep violet blue (sometimes varying to black or brown), leaf green, turquoise, yellow,[41] and a colourless glaze or a white slip which served as white colour, though at times the white was represented merely by leaving the unglazed body or biscuit to appear. These coloured glazes differ from the on-glaze painted enamels in that they are applied direct to the body of the ware, and are fired at a relatively high temperature in the cooler parts of the great kiln, a circumstance expressed by the French in the concise phrase, _couleurs de demi-grand feu_.[42]