a fine sort of earthen-ware, chiefly manufactured in China, and thence called china-ware. The most just idea we can form of the porcelain, or china-ware, ware, is, that it is an half vitrified substance, or manufacture, in a middle state between the common baked earthen ware of our vulgar manufactures, and true glas. This is the essential and distinctive character of porcelain; and it is only by considering it in this light, that we are to hope of arriving at the perfect art of imitating it in Europe. This attempt is to be made on these principles in two different manners. The one by finding from appropriated matter, on which fire acts with more than ordinary strength, in the time of its passing from the common baked state of earthen ware into that of glas. The other is to compose a paste of two substances, reduced to a powder; the one of which shall be of force to resist a very violent fire, so as not to become vitrified in it; and the other a matter very easily vitrifiable. In the first case, the matter is to be taken out of the fire at the time when it is imperfectly vitrified; and in the other, the compound mass is to remain in the furnace, till the one substance which is the more easily vitrifiable is truly vitrified; and being then taken out, the whole will be what porcelain is, a substance in part vitrified, but not wholly so. The first method is that by which the European porcelain has been generally made, which though it may be very beautiful, yet it is always easy to distinguish even the finest of it from the china-ware; and the nature of the two substances appears evidently different: these owing all their beauty to their near approach to vitrification, are made to endure a long and violent fire, and are taken from it at a time when a little longer continuance should have made them perfect glas; on the contrary, the china ware being made of a paste, part of which is made of a substance in itself scarce possible to be vitrified, bears the fire in a yet much more intense degree than ours, and is in no danger of running wholly into glas from it.
The two substances used by the Chinese, are well known by the names of petunse and kaolin; and on examining these, it appears very evident, that we have in Europe the very same substances, or at least substances of the very same nature, capable of being wrought into porcelain equally beautiful and fine.
Porcelain-shell. See Cypraea.
Porcupine, in zoology. See Histrix.
Pore, in anatomy, a little interstice or space between the parts of the skin, serving for perspiration.