and the under-glaze colors, they will always be vague and meaningless terms.
Briefly, then, when a china plate, for instance, is being made, it is first moulded from moist, pliable clay, and is then subjected to an intense heat, whence it issues from the kiln in what is called the "biscuit." In this condition it presents a dull, dry appearance, is quite porous, and has a comparatively rough surface. As an article of utility, it is practically useless ; as it is incapable of retaining liquids, because of its porosity.
This piece of biscuit is then brushed over with, or dipped into, the glaze (which is in a fluid form), and fired again.
Glaze is a colorless, transparent substance, partaking of the nature of glass, so that when fired and fused to the body of the ware the article is literally enclosed in a thin film of glass.
Both the body and the glaze shrink in firing, being divested of all moisture ; and in order to make a perfect article the must contract in the same proportions. In other words, body and glaze must fit each other.
When a piece of ware becomes covered with small irregular cracks, it is said to be "crazed : 1
1 The Chinese manufacture a ware in which the crazing is intentionally accomplished. It is called "crackle ware," and is regarded with special distinction, artistically and commercially.
