Hero of Alexandria

Text C

IX. Reading and Comprehension.

Exercise 19. Describe the trends in the modern machine-building industry. Use the table of ex. 18.

VIII. Oral Practice.

Exercise 20. Read the text C without a dictionary for 6 min.:

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.:

Дата добавления: 2015-03-29