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Science





Iron's early history

No one knows how long man has used iron. Iron ore is to be found in almost all countries, and primitive man in many lands knew how to use it many centuries ago.

One can only guess (догадываться) as to the way man first learned that ore could be melted and used for his tools. Perhaps some primitive man's camp fire first smelted (плавить) iron by

accident. Legend says that fifteen hundred years before Christ1 a forest fire showed the people of the island of Crete (Крит) how to make iron. Pictures which date back to thirty-five hundred years before Christ show Egyptians smelting iron with the air of a goat-skin bellows (мехи из козьей кожи). However2 man may have found out how to make iron, it was made by the same method in ancient times in Africa, in China, in India, as well as in the countries around the Mediterranean (Средиземное море). In England, Caesar (Цезарь) found the Britons making iron very much as the explorer may still find it made in remote parts of Africa and Asia. Even the Romans were unable to make much improvement on the process of making iron. Rome produced thus all the metal with which Caesar armed his victorious legions. The iron which held together the oak of Columbus's ships was made in a simple fire-place like a blacksmith's forge (кузнечный горн). Iron for Washington's cannon and muskets3 was made in tall furnaces not unlike big stone chimneys4. The fire was fed by the forced draft (воздушный поток, сквозняк), commonly produced by a water wheel.

We must not think that because the ancients had difficulty in making iron they could not make good iron. The fact is that their product was as good as, and even better than, most of the iron we have today. The stories are true of the splendid shining swords (мечи) of ancient heroes. We have learned merely how to make iron more easily and more cheaply. The principle ofiron-making has always been the same, whether it was5 in Central Africa or Rome, in the time of George Washington or Andrew Carnegie6; hot fire smelts the iron out of the ore.

Coelacanth 7

The Smithsonian Institution8 has put on exhibit a "living fossil" (живую окаменелость) fish, the coelacanth, in the National Museum. Another is at the American Museum of Natural History. The coelacanth was believed by scientists to have become extinct (вымерший) 70,000,000 years ago. But a specimen (экземпляр, образец) was caught alive in 1938 in the Indian Ocean off South Africa; since 1952, twelve have been caught near Madagascar. The coelаcаnth has two pairs of limb-like fins9 and a rudimentary lung. These are like those from which the legs, arms and lungs of man and other land vertebrates (позвоночные) could have evolved. Paleontologists have traced the ancestry (родословная, предки) of the coelacanth back 325,000,000 years to the group of creatures (существ) from which all land vertebrates descended (произошли). The specimen put on exhibit in Washington is a forty-three-pound fifty-one-inch male (самец).

Date: 2015-12-13; view: 385; Нарушение авторских прав; Помощь в написании работы --> СЮДА...



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