dflbv20050102

20.09.2020 21:41

Английский язык

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Много , в краце, ! exercise 4. write a short composition of the text. текст: iron was in limited use long before it became possible to smelt it. the first signs of iron use come from ancient egypt, where around 4000bc small items, such as the tips of spears and ornaments, were being fashioned from iron recovered from meteorites. about 6% of meteorites are composed of an iron-nickel alloy, and iron recovered from meteorite falls allowed ancient peoples to manufacture small numbers of iron artifacts. meteoric iron was also fashioned into tools in north america. beginning around the year 1000, the people of greenland began making harpoons and other edged tools from pieces of the cape york meteorite. these artifacts were also used as trade goods with other arctic peoples: tools made from the cape york meteorite have been found in archaeological sites more than 1000 miles (1600 km) away. when the american polar explorer robert peary shipped the largest piece of the meteorite to the american museum of natural history in new york city in 1897, it still weighed over 33 tones. the name for iron in several ancient languages means “sky metal” or something similar. in distant antiquity, iron was regarded as a precious metal, suitable for royal ornaments. beginning between 3000 bc to 2000 bc increasing numbers of smelted iron objects (distinguishable from meteoric iron by their lack of nickel) appear in anatolia, egypt and mesopotamia. the oldest known samples of iron that appear to have been smelted from iron oxides are small lumps found at copper-smelting sites on the sinai peninsula, dated to about 3000 bc. some iron oxides are effective fluxes for copper smelting; it is possible that small amounts of metallic iron were made as a by-product of copper and bronze production throughout the bronze age. in anatolia, smelted iron was occasionally used for ornamental weapons. also, the egyptian ruler tutankhamen died in 1323 bc and was buried with an iron dagger with a golden hilt. an ancient egyptian sword bearing the name of pharaoh merneptah as well as a battle axe with an iron blade and gold-decorated bronze haft were both found in the excavation of ugarit. iron did not, however, replace bronze as the chief metal used for weapons and tools for several centuries, despite some attempts. working iron required more fuel and significantly more labor than working bronze. then, between 1200 bc and 1000 bc, iron tools and weapons displaced bronze ones throughout the near east. this process appears to have begun in the hittite empire around 1300 bc, or in cyprus and southern greece, where iron artifacts dominate the archaeological record after 1050 bc. mesopotamia was fully into the iron age by 900 bc, central europe by 800 bc. the reason for this sudden adoption of iron remains a topic of debate among archaeologists. one prominent theory is that warfare and mass migrations beginning around 1200 bc disrupted the regional tin trade, forcing a switch from bronze to iron. egypt, on the other hand, did not experience such a rapid transition from the bronze to iron ages: although egyptian smiths did produce iron artifacts, bronze remained in widespread use there until after egypt’s conquest by assyria in 663 bc. iron smelting at this time was based on the bloomery, a furnace where bellows were used to force air through iron ore and burning charcoal. the carbon monoxide produced by the charcoal reduced the iron oxides to metallic iron, but the bloomery was not hot enough to melt the iron. instead, the iron collected in the bottom of the furnace as a spongy mass, or bloom, whose pores were filled with ash and slag. the bloom then had to be reheated to soften the iron and melt the slag, and then repeatedly beaten and folded to force the molten slag out of it. the result of this time-consuming and laborious process was wrought iron, a malleable but soft alloy containing little carbon. wrought iron can be carburized into a mild steel by holding in it a charcoal a fire for prolonged periods of time. by the beginning of the iron age, smiths had discovered that iron that was repeatedly reforged produced a higher quality of metal. quench-hardening was also known by this time. the oldest quenchhardened steel artifact is a knife found on cyprus at a site dated to 1100 bc.