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 of 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 p
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If good intentions and good ideas were all it took to save the deteriorating atmosphere, the planet’s fragile layer of air would be as good as fixed. The two great dangers threatening the blanket of gases that nurtures and protects life on earth-global warming and the thinning ozone layer--have been identified. Better yet, scientists and policymakers have come up with effective though expensive countermeasures.
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(3) CFCs-first fingered as dangerous in the 1970s by Sherwood Rowland and Mario M01ina, two of this year’s Nobel-prizewinning chemists--have been widely used for refrigeration and other purposes.
(4) If uncontrolled, the CFC assault on the ozone layer could increase the amount of hazardous solar ultraviolet light that reaches the earth’s surface, which would, among other things, damage crops and bring disasters to environment.
(5) Thanks to a sense of urgency triggered by the 1985 detection
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