Exercises

I. Give Russian equivalents of the following phrases used in the text:

the fundamental principles of a computer; to receive education; to be under the influence of; to be unaffected by; contemporary developments in science; to insist upon the application of mathematics; to write a paper on a problem; an idea occured to him; to support a project; to devote efforts to…; the rest of his life; to solve a series of problems; to buils an arithmetic unit from drawings.

II. Read the text and stay the main idea.

III. Paraphrase the following sentences. Instead of the words and word-combinations given in the left column, use their synonyms from the right column:

1. He understood all the basic laws of modern digital computers.

2. All that time mathematics in Cambridge was dominated by Newton.

3. Babbage was a prominent man among his contemporaries.

4. He showed a working model of his machine in 1822.

5. The Royal Society backed his project.

6. He gave much time to the development of his machine.

7. Babbage was not understood by his contemporaries.

IV. Write a logical plan of the text.

V. Find a key sentence in every paragraph.

VI. Make up summary of the text, using the words from exercise 3.

VII. Write an abstract of the text.

Text 7

Dr. Roentgen Discoveres X-Rays

If we look back into history to brace the beginnings of the Atomic Age, we may start the story with an experiment performed by a tall, scholary, bearded professor of physics in the Bavarian town of Würzburg late in the year 1895.

Dr. W. K. Roentgen was fifty years old when he turned his attention to problems that had puzzled him for some time.

One day, now famous in history, November 8, 1895 - Friday afternoon, to be precise, Roentgen, having dined with his wife, hurried back to the laboratory to try another experiment. He had been experimenting with a Lenard tube which was equipped with an aluminium window so thin that the fast-moving electrons or cathode rays, could pass through it to the air. It was the study of these rays that had intrigued him. This particular evening, however, he took a thick-walled glass discharge tude through which the cathode rays could not pass. He wrapped it in a piece of carboard, sealing the edges, so that no light from the tube would leak out.

Then he drew the shades on the windows making sure that the room was completely dark. When his eyes became accustomed to the blackness, Roentgen switched on his high-voltage machine. No Light escaped from the covered discharge tube. Suddenly his eye was caught by a faint greenish light about three feet away from the tube. It was strange. Almost instinctively he switched off his apparatus. The light disappeared. But it glowed again when he once more applied the high voltage to the tube. Whatever the glow was, clearly it was caused by the apparatus. Roentgen struck a match and looked for the source of the light. It was coming from the piece of cardboard that he had covered with crystals of a chemical called berium platinocyenide. How strange that it should glow so far away from the discharge tube.

Holding the piece of cardboard closer to his apparatus, the scientist observed that it now glowed brilliantly. Obviously something - some rays-must be coming from the tube and causing the crystals to glow. A less skilled observer might have passed over the effect, but Roentgen realized that the rays, whatever they might be, were most peculiar. For they penetrated not only the glass walls of the tube and the cardboard in which it was wrapped, but even through the thickness of a book which he placed in their way.

Roentgen's interest was greatly stimulated by the mystery of the strange invisible rays that were produced inside his glass tube. They could penetrate solid matter and cause barium crystals to fluorescene. Needing a name for these unknown rays, he called them "X-rays".

 He now become completely engrossed in his investigation of X-rays. He performed a series of systematic experiments, and by the end of the year he had learned a great deal about them. He found that they affected photographic film, causing in to turn black when it was developed. He wrapped a piece of photographic film in black paper, to protect it from light, placed a metal key on it and then exposed it to X-rays. When he developed the film, he found the key had left its image there. The X-rays had blackened the film all around it, but where the key had been, the film was untouched by the rays. They had been stopped or absorbed by the heavy metal of the key.

Not content with photographing inanimate objects, Roentgen asked his wife to help him in an experiment. He placed a paperwrapped photographic film under her hand and exposed it for fifteen minutes to X-rays from his tube. When the film was developed the bones of her fingers showed up clearly in the faint outline of her hand, the bones having stopped more of the rays than had the fleshy part of the hand. This experiment initialed a whole era in medical diagnosis - the science of roentgenology or radiology.