Exercise 18. Study the table and
A) find in the text B passages which are described in the table;
B) complete the table if necessary.
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What else? What else?
VIII. Oral Practice.
Exercise 19. Describe the trends in the modern machine-building industry. Use the table of ex. 18.
IX. Reading and Comprehension.
Exercise 20. Read the text C without a dictionary for 6 min.:
Text C
Hero of Alexandria.
About sixty years after death of Archimedes, Hero of Alexandria was born. Nobody knows the exact date of his birth, but according to the best authorities, he lived about 150 B.C. In addition to being a great mathematician, he invented the siphon, the gearwheel, the pump, the water clock and the steam engine.
His book on mechanics translated into Arabic was carefully studied by mechanics and engineers of the sixteenth century. In this remarkable book Hero lists and describes five simple ways by which an unusually heavy weight may be lifted and moved with minimum effort. These five principles form the basis of all the machinery in the world today and, though described in detail by Hero, their practical application to machinery did not come about for more than a thousand years. They are: the lever, the wheel and axle, the pulley, the wedge, the screw.
While it is true that the invention of the screw is attributed to Archimedes and the wedge and the lever were known long before Hero's time, he was the man, who showed for the first time that all machinery is based on these five important principles, and how to apply these principles to machinery — such as it was in these early times.
Neither he nor anyone else of his time realized the importance of these inventions. Hero's book on pneumatics, which was translated into Italian in 1549 and later into English, described more than seventy totally useless inventions, most of which embody important basic principles. Their main function was to entertain.
Exercise 21. Find the correspondence:
| Hero of Alexandria lived… His inventions were… Hero described and listed… He described… The main function of Hero’s invention was… | the siphon, the gearwheel, the pump, the water clock, the steam engine. about 10 B.C. to entertain. how the heavy weight may be lifted and moved with minimum effort. five basic principles of the machinery. |
Exercise 22. Put the following statements in the right order:
1. All his inventions were used to entertain only.
2. Hero lived about 10- B.C.
3. Among his inventions are the siphon, the gearwheel, the pump, the water clock, and the steam engine.
4. Hero of Alexandria was a great mathematician and inventor.
5. Practical application of these five principles to machinery came about more than a thousand years later.
6. Hero also showed for the first time that all machinery is based on these principles.
7. Hero’s book on pneumatics described more than seventy of his totally useless invention.
8. The five principles described by Hero are the lever, the wheel and axle, the pulley, the wedge, the screw.
9. In his book on mechanics, Hero listed and describe the five basic principles of mechanics.
10. Neither Hero nor his contemporaries realized the importance of his inventions.
Exercise 23. Answer the following questions:
1. When did Hero live?
2. What were his famous inventions?
3. Why is his book on mechanics so important for the future of the machinery?
4. What are the five principles of machinery which were listed by Hero?
5. Why were the inventions described in Hero’s book useless?
Exercise 24. Read the text D without a dictionary for 8 min.:
Text D.
JAMES WATT
James Watt was born in Greenock, Scotland, and was taught at home. Later he went to Greenock Grammar School.
His technical expertise seems to have been obtained from working in his father’s workshop and from early in life he showed academic promise. His early formal training was as an instrument maker in London and Glasgow.
Watt combined the expertise of a scientist with that of a practical engineer, for later he was not only to improve the heat engine but also to devise new mechanisms.
Watt was interested in making experimental models of steam engines and this marks a historical milestone in engineering development, for they were the first experimental apparatus purposely constructed for engineering research. Watt's early interest in steam arose from experience in repairing a model steam engine in 1764, and in 1765 he invented the separate steam condenser. In 1769 he took out a patent on the condenser in which steam came into direct contact with cold water. That was a milestone by which steam engineering reached its practical and usable
form.
In 1784 he took out a patent for a reaction turbine at a time when continental engineers were only considering similar approaches. An improved centrifugal governor was to follow in 1788 and a design for a pressure gauge in 1790.
In the development of the steam engine James Watt represents the perfecting of a sequence of stages beginning with the Newcomen engine and ending with the parallel motion and sun/planet gearing. The latter is said to have been invented by William Murdock but patented by Watt.
In the scientific field watt’s finest memorial, apart from steam engines, is his establishment of the unit of power – the rate of doing work. He coined the term horsepower (hp), one horse being defined as equivalent to 33,000 ft lb/min.
James Watt died in 1819 in Heathfield, after a life of incomparable technical value. Later, a statue to Watt was placed in Westminster Abbey.
Exercise 25. Complete the table using the information from the text D:
| Time | Watt’s activity and its results |
| repairing a model steam engine ---------- ---------- ---------- ---------- ---------- |
X. Oral Practice.
Exercise 26. Comparethe inventive activities of James Watt and Hero (text C and text D); and prove your position.
SUPPLEMENTARY READING