The "reticulated" cups are very curious and interesting; the inner cup for holding the tea is surrounded by another pierced through its side with a variety of designs. It is difficult to see how these could have been baked together without fusing and fastening them. The "grains-of-rice" cups are made by cutting the design through the body, which spaces are then filled with a translucent glaze; the cut spaces show when held up to the light, and resemble in most cases grains of rice. The engraving (Fig. 112) represents a pot in Mr. Avery's collection. Just when the "crackle" decoration was applied cannot well be known, but it was in vogue in the beginning of the Ming dynasty. It seems that the purity of the paste was greater during this period than later, and that the colors, therefore, became more brilliant. "Crackle" china has long been prized, and much sought for, especially the best specimens. This ware shows a network of veins covering the whole piece, the lines of which are sometimes filled with a color such as brown, black, green, etc. It remains a mystery to us how this effect is produced, though it is still made. Marryat seems to believe that the crackle is produced in the glaze, and possibly by subjecting it, when heated, to sudden cold, which causes the contraction and crackle; a close examination shows that the crackles are in the body itself, and are afterward covered with the glaze. This decoration is curious rather than beautiful. The crackles vary in size from a half-inch to a very fine network; and this last is most valued. Mr. Franks gives the following as the result of his investigations: "This is one of the most peculiar productions of the art of the Chinese potter, and has not been successfully imitated elsewhere. Occasionally European pieces assume a crackled appearance, but this has not been intentionally produced, and has been subsequent to the baking.