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Electromagnetic waves

Radio waves, light, X-rays and some cosmic rays - they all belong to the same family. They travel at trie velocity of light.

The wave has both electric and magnetic components which are bound together. At the end of its travel the wave gives up energy. The ether waves are those we know as wireless waves.

When the waves are too long they are "seen" as infrared, when they

are too short they are "seen" as ultra-violet. Shorter than the ultra-violet are X-rays and far shorter than the shortest of these are the "gamma" rays, and finally the cosmic rays.

The penetrative power of these increases as the wavelength decreases. To sum up: all these electromagnetic waves travel through the ether at the same enormous speed; the different effect which they produce depends entirely upon their length.

Some more words about ultra-violet and X-rays.

Ultra-violet rays are familiar to most people as the particular art of sunlight that is "health-giving".

The effect of the ultra-violet rays is to produce in the skin the vitamin that is important for the promotion of bone-growth.

The use of these rays in diagnosis is a powerful weapon of medicine.

One of the most valuable uses of ultra-violet rays in industry is the testing of the quality of certain goods.

X-raying is very important in metallic weldings.

X-ray were discovered by Roentgen after whom the rays are some­times called. The discovery of X-rays was quickly followed by its application to medicine.

Revision exercises

I. Translate the following sentences into Ukrainian paying

attention to the Objective Infinitive Construction (Complex Object).

1. Have you heard how he spoke on the control of space vehicles from

the Earth? 2. Have you heard him speak on the control of space vehicles

from the Earth? 3.I saw them test this device. 4.I heard her speak English.

5. They did not watch us make experiments in the lab- 6- We did not notice

him leave the lecture hall.

II. Translate the following sentences paying attention to the func­tions of the Infinitive construction.

1. We are said to live in the age of atomic energy. 2. We suppose the earth's new satellite to start its revolution around the earth very soon. 3. The earth's new satellite is supposed to start its revolution around the earth very soon. 4. In ancient times the sun was thought to be revolving round the earth. 5. The radio was supposed to have been invented by Marconi. 6. The stu­dents are supposed to work in the laboratory. 7. The students are offered to work in the laboratory. 9. He was expected to come in time. 10. He was made to come against his will. 10. Sedov is known to have died on his way to the North Pole. 11. Scientists expect titanium to be widely used in indus­try.

III. Translate into Ukrainian paying attention to the Subjective Infinitive Construction (Complex Subject).

1. The lecture was said to be very interesting. 2. The members of the committee are reported to come to an agreement. 3. The English delegation is believed to come at the end of the month. 4. She seems to know English and French. 5. He proved to be a good teacher. 6. This school is considered to be the best in the town. 7. The weather appears to be improving. 8. The doctor happened to be there at the time of the accident. 9. She seems to be waiting for you. 10. Lake Baikal is said to be the deepest in the world. 11. This picture proved to be the best at the exhibition. 12. These two scientists happened to work at the same problem.