Translate and memorize the following words. 2. Read and translate correctly:

commercial	immediately	retain
malleable	occasionally	inherent
insufficient	whilst	presumably
unalloyed	appreciably	impermeable

2. Read and translate correctly:

on a commercial scale; whilst it is oxidized; insufficient to have any commercial impact; when unalloyed; the creep resistance; atmospheric corro­sion; the electro-negative character; partly ionic and partly covalent.

3. Pay attention to the word combinations in bold type, translate them into Russian:

1. As early as in 19th century... 2. This experiment is as important as.... 3. As far as this report is concerned.... 4. As far back as in 1947... 5. As late as in the 18th century occurs... 6. As long as this reaction occurs... 7. As soon as he comes.... 8. As early as 200 B.C…

4. Translate the following word combinations, mind the Participles II:

the method involved was; the experiment spoken of is; the lecture followed by the experiment took place; the data referred to must be; the report presented involved some data; the figures summed up resulted in; the book translated consisted of 2 parts; the work done helped greatly; the ore found contained; the solution used is to be heated.

5. Translate the following sentences, mind the Infinitives:

1. The copper to be used must be pure. 2. The metal is to be used in our experiment. 3. To use this solution we have to heat it. 4. To use these figures is to complete this, work. 5. The method seems to be useful in this work. 6. The work done proves to be of great importance. 7. They found this substance to melt at a low temperature. 8. The application of zinc is known to be important in heavy industry. 9. Zinc is known to be a silvery white metal. 10. This metal appears to be readily dissolved by most mineral acids.

6. Read the text, analyse the grammar constructions:

BRASS

The addition of zinc to copper to form brass is the oldest and one of the most important applications of zinc. The art of producing bronze by alloying copper with tin was developed relatively early and was one of primitive man's greatest technological advances, but due to the difficulties in­herent in the metallurgy of zinc, brasses do not seem to have been produced until the first or second century B.C., when the cementation process was practised in India and China, and also in Europe by the Romans.

A mixture of zinc oxide (as calcined calamine) and charcoal was placed in a crucible and covered by a layer of pieces of copper. The crucible was heated to 1000°C, when the zinc oxide was reduced and formed zinc vapour, which dissolved in and was retained by the copper. As the zinc content of the copper rose to approximately 30 per cent, the alloy began to melt and ran down to the bottom of the crucible, and at the end of the reaction was cast into moulds – usually made of stone slabs – and later hammered into the shapes required. The process did not involve the separation of zinc as metal. The method was the main source of brass production for many centuries. It was not capable of producing alloy containing more than 30 per cent zinc.

When methods for producing zinc were developed in India and China in the thirteenth and fourteenth centuries A.D., and the metal became generally available, some brass was made by directly alloying the two metals. This method was more controllable and enabled alloys with a higher zinc content than 30 per cent to be made if required, but the cementation process was presumably cheaper and its use did not die out for many years.

The brasses constitute an important series of alloys, since by varying the composition and heat treatment, a wide range of mechanical properties can be produced with valuable characteristic and excellent corrosion resistance. They form one of the three major outlets for zinc metal.