Text 10
Precious Metals
Why are some metals so much more valuable than others? Gold, silver and platinum have been highly valued for centuries because of their scarcity, beauty and high qualities. The result of the rush for these metals was death, blood and tragedy.
When Christopher Columbus discovered the Americas in 1492, Spanish expeditions soon followed, and though they are much criticised for their cruelty, greed and treachery, the military achievements of the 'Conquistadors' were remarkable. First they conquered Mexico and took away its valuable treasures. Seeking more land and wealth they invaded Peru, home of the Incas. Here they murdered the king and stole his vast hoard of gold - probably the greatest in the world. The natives were enslaved and set to work to win more gold. Later the Spanish conquered Chile and Bolivia, both of these countries being rich in precious metals, particularly silver.
To the metallurgists, the most exciting discovery made by the Spaniards was the finding of platinum in the silver mines of Mexico. At that time the new metal was
regarded as more of a nuisance than of value. It could not be melted by any known method, though it was possible to make a very realistic imitation gold from it. Later it joined the group of precious metals and is now used for jewellery and in industry. Its high melting point makes it suitable for electrical contacts where the heat of sparks would melt other metals. In the chemical industries its resistance to corrosion is of great value.
Gold is the most malleable of all the metals. It can be hammered into sheets so thin that 250 of them would equal the thickness of a sheet of paper. It is also the most ductile metal. One gram of gold can be drawn into a wire 1.8 miles in length.
Gold is the least chemically active of all metals and does not combine with oxygen to form rust. This ability to resist corrosion makes it very durable, i.e. it may last for centuries. Pure gold is too soft to be used in jewelry so it is usually alloyed with other metals. The proportion of gold in an alloy is measured in karats. Pure gold is 24 karats. A 14 karat gold ring is an alloy of .about 58% of gold and small percentages of copper and silver.
Silver is similar to gold in many ways. Like gold, it is very malleable and ductile and so it is also used for jewelry. Silver differs from gold in that it is more reactive and tarnished when exposed to the traces of sulfur in the air. (Silver sulfide, a black deposit, forms on its surface). Pure silver is too soft and so it is usually alloyed with copper to increase its hardness and durability. Sterling silver is 92.5 percent silver and 7.5 percent copper. Silver is used for coins and for photographic film because certain compounds of silver, such as silver bromide, reflect light. Silver is the best conductor of electricity known.
Task 2. Lexical Exercises
Exercise 1. Find the English equivalents for the words and -word-combinations given below. Use them in the sentences of your own.
огромный запас золота; засесть за работу; рассматривать; имитация золота;
известный метод; драгоценные металлы; высокая точка плавления; химическая промышленность; ювелирное украшение; измерять; терять блеск (окисляться);
серебро высшей пробы; фотопленка; серебряные копи.
Exercise 2. Match the English words and word-combinations given below with their Russian equivalents.
1. to criticize for 1. в поисках новых земель и богатства
2. remarkable achievements 2. повысить износостойкость
3. seeking more land and wealth 3. богатый драгоценными металлами
4. to set to work 4. растянуть в проволоку
5. to equal smth 5. отражать свет
6. to increase durability 6. засесть за работу
7. to reflect light 7. быть равным чему-л
8. rich in precious metals 8. наименее химически активный металл
9. the least chemically active metal 9. удивительные достижения
10. to draw into a wire 10. критиковать за
Exercise 3. Answer the following questions.
1. What are the precious metals valued for? 2. When did the Spanish expeditions set for South America? 3. What did they find there? 4. What was their most exciting discovery? 5. Why is it easy to hammer gold into thin sheets? 6. Where is gold used? 7. What are the properties of silver?
Exercise 4. In the text given above you could find the fragments Of the definitions of gold and silver. Make them complete definitions. Listed in the box are some guidelines for writing good definitions. They are followed by poorly written definitions. Say, what is wrong with them and correct them.
| 1. Identify the class. You may also use descriptions, comparisons, examples. 2. Be precise. Do not only identify the class, but give the characteristics that differentiate this object or phenomenon from others. 3. Use negative definitions (like 'An apple is not a vegetable') when you think people have a wrong idea. But then follow it with a proper definition. 4. Be objective. Always remember about those you are speaking to. A child needs an easier and more detailed definition. |
1. An apple is round, red and about the size of a fist.
2. An astronomer is a scientist.
3. Radium is an element.
4. A pizza is something really good to cat.
5. Helium is light.
6. Barometer measures air pressure.
7. Conduction transfers heat.
8. An agronomist is a person who practises agronomy.
Exercise 5. Translate at sight.
Metals and Non-metals
The 105 elements do not, fortunately, exhibit 105 completely different sets of properties. When the major properties are considered it is found that the elements fall into one or two groups, the metals or the non-metals. The contrast between the properties of these two groups is given below. It is not to be expected that all elements in one class will agree m every detail; some differ in one or two properties from the others of their class; these exceptions are indicated in brackets.
| Metals |
| Non-Metals | |
|
| Physical properties |
| |
| 1. Solid at room temperature (mercury is the only liquid metal) 2. Have a high density (except potassium and sodium) 3. Can be moulded by pressure, i.e. they are malleable 4. Have high melting points and boiling points 5. Are good conductors of heat, electricity 6. Can be drawn into a Wife, i.e. they are ductile | 1. Many are liquids and gases at room temperature 2.Density is usually low 3. Solid non-metals are brittle 4. Have low melting points and boiling points 5. Are poor conductors of heat and electricity (graphite is the only good conductor of electricity among non-metals ) 6.Cannot be drawn into a wire | ||
Chemical properties
| 7. Have basic oxides 8. React with dilute acids forming salts 9. Form positive ions 10. Are liberated at the cathode during electrolysis (hydrogen during electrolysis acts as a metal) | 7. Have acidic oxides 8. Salts of non-metals do not are brittle 9. Form negative ions 10. Are liberated at the anode during electrolysis |
The chemical properties are much more conclusive than the physical properties for deciding whether a particular element is to be regarded as a metal or a non-metal, e.g. if an element forms a basic oxide it must be classified as a metal. A basic oxide is never formed by a non-metal
Text10
Silverware and Plate Industry
While reading the text we shall return to Sheffield - the biggest centre of British metallurgy.
The story of silverware and the story of the highly-prized Old Sheffield plate are inextricably linked. Two hundred and fifty years ago cutlery manufacture was the only important industry in Sheffield and knife handles were the only objects made in silver.
As a result of mid-eighteenth century pioneering work by Thomas Boulsover, a Sheffield cutler, and Joseph Hancock who developed a method of plating a copper ingot with silver by fusion, a new industry came into being.
The plated ingot was rolled as if it was one metal, and by the 1760's several firms were engaged in the manufacture of Old Sheffield plate tableware. Early examples are now coveted collectors items.
Sheffield manufacturers found a ready market: a growing middle class who turned to the cheaper, beautiful articles which resembled silver and were almost as durable.
Machinery invented for the mass production of Sheffield Plate turned out to be suitable for the economical production of silver tableware and from this a sterling silver industry sprang up.
In 1773 an Act of Parliament granted the town its own Assay Office; the Sheffield mark - a crown. After 1904 the Office was also authorised to assay gold on which its mark is the York rose. The present Assay Office is in Portobello Street.
The silverware trade is now the largest industry carried on in Sheffield with non-ferrous metals; the emphasis is on specialists, high grade work manship and two well-known pieces regularly made here are the Grand National trophy and Lonsdale Belts awarded to the winners of British boxing title fights
Task 2. Lexical Exercises
Exercise 1. Find the English equivalents for the words and word-combinations given below and use them in the sentences of your own.
столовое серебро (изделия из серебра); ножовщик; ножевые товары; медная болванка; напоминать серебро; пробирная палата; уполномоченный; награждать;
оборудование (станки); основное внимание уделяется.
Exercise 2. Match the English words and word-combinations given below with their Russian equivalents. Use them in the sentences of your own.
| 1. plate 2. inextricably linked 3. pioneering work 4. to plate by fusion 5. a new industry came into being 6. high grade workmanship 7. York rose 8. Grand National trophy 9. Lonsdale Belt | 1. плакировать путем сплавления 2. появилась новая промышленность 3. сложным образом связаны друг с другом 4. мастерство высокого класса 5. Белая роза (эмблема династии Йорков - королевской династии 15в) 6. изыскательская работа 7. столовое серебро 8. высшая награда боксеров-профессионалов - богато украшенный пояс, вручается чемпиону Великобритании, завоевавшему это звание три раза подряд 9. приз победителю ежегодных крупнейших скачек с препятствиями |
Exercise 3. Answer the following questions.
1.When did the story of Old Sheffield silverware and plate begin? 2. What method was developed in the middle of the 18th century? 3. Why did the plate industry develop so rapidly? 4. Does Sheffield have its own Assay Office? 5. Which two well-known National trophies are made in Sheffield?
Exercise 4. From the choices given choose a word or phrase which could be substituted for the underlined word or phrase without changing its meaning.
1. These two stories are closely linked.
a) connected b) mixed c) integrated
2. A new industry came into being in the middle of the 18th century.
a) developed b) sprang up c) continued
3. A growing middle class wanted to buy cheaper, beautiful tableware.
a) extending b) developing c) increasing
4. The Assay office was authorized to assay both silver and gold.
a) was allowed b) was given the right c) was ready
5. In Sheffield two well-known trophies are made.
a) respectable b) popular c) famous