Pottery is the name given to all kinds of pots and other tools made from clay and other minerals when they have been hardened by heat in the potter's kiln.
Pottery is one of the oldest crafts, which began to be practiced as soon as man learned to control fire, and long before the melting o£ metals. Pottery enabled man from very early times to make vessels for storing and cooking food, for carrying water, etc. Early vessels were shaped by hand and probably hardened in a big fire.
A great advance in pottery followed the invention of the potter's wheel and the kiln. It is not known where the potter s wheel was first used, but it is believed that by 3500 B.C. potters in Central Asia were using some kind of wheel. Its use spread west and east to Egypt. China, and then to Ancient Greece and Rome.
At first the wheel was nothing more than a small disc, turned round by hand. Later it was improved and could be turned round by the potter with his feet. Such a wheel was probably in use in Egypt by about 200 B.C. It was certainly still in use in Europe at the beginning of the nineteenth century. Modern potters wheels are power driven.
There are three principal ways pottery articles are made. They may be shaped by hand,or the wet clay may be thrown on the potter s wheel and shaped against the spin with the fingers or some tools. Or, the wet clay may be put in a pre-shaped 'form'.
After the pots have been shaped. they are slowly baked in the kiln. This prcxluces chemical chan-丄 ges in the clay which have a hardening effect. The time taken for firing pottery varies with the size of《 the kiln and the type o£ clay. It can take from 24 hours to 2 weeks.
Clay is leaking by nature. If a pottery article is to hold water, it must be 'glazed' Glaze consists of the raw materials of glass,ground together and mixed with water. The glaze is sprayed on to the pot which is then heated in the kiln again until it is covered with a very thin layer of glass. This seals the tiny holes in the clay and gives us the various and oven dishes we know so well today.
The passage is probably written for ______.
A.technicians B.general readers C.history students D.art student正确答案B
