Pottery is the name given to all kinds of pots and utensils made from clay and other minerals when they have been ‘fired’, that is, hardened by heat in the potter’s kiln. Articles made of pottery include plates, cups and saucers, cooking dishes, wall and floor tiles, chemical storage jars, bathroom fittings, filters, drain pipes, electrical insulator and ornaments for the home.
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 of metals. It enabled him from very early times to make vessels for storing and cooking food, for carrying water, and for ritual burial purposes. Early vessels were shaped by hand and probably ‘fired’ in a big bonfire by covering them over with dried grass and dead branches, which were then set alight.
A great advance in pottery followed the invention of the potter’s wheel and the kiln. It is not certainly known where the potter’s wheel was first used, but it is thought that by about 3500 B.C. potters in Central Asia were using some kind of wheel. From there its use spread west and east to Egypt, Crete, China-and then to Ancient Greece and Rome.
At first the wheel was nothing more than a small disc, turned on a pivot by hand, but later it was improved by raising it and providing it with a larger circular platform near the ground as well which could be rotated by the potter with his feet. Such a wheel was probably in use in Egypt by about 200 B.C., though this is only conjecture; but it was certainly still in use in Europe at the beginning of the nineteenth century. In the eighteenth century, however, the potter’s wheel was improved so that it could be worked by a treadle, or turned by an assistant. Modern potters’ wheels are power driven.
There are three principal ways articles may be made of pottery. They may be simply shaped by hand. They may be thrown on the potter’s wheel and shaped against the spin with the fingers or some scraping tool. Thirdly, the wet clay may be put in a pre-shaped ‘form’ of plaster-of-Paris.
After the pots have been made, they are slowly baked in the kiln. This produces chemical changes in the clay which have a hardening effect. The time taken for firing pottery varies with the size of the kiln and the type of clay. It can take anything from 24 hours to as long as 2 weeks.
If pottery is to hold water, it must be ‘glazed’, since clay is porous by nature. Glaze consists of the raw materials of glass, ground together and mixed with water to a creamy consistency. The glaze is sprayed on to the pot which is then heated in the kiln again until it is, in effect, covered with a very thin layer of glass. This seals the pores in the clay and gives us the versatile table and oven dishes we know so well today.