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READING. Ex 42 Read the text, and do the assignments coming after it

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Ex 42 Read the text, and do the assignments coming after it.




Scientists working on a problem do not know and sometimes can't even guess what the final result will be. Professor Röntgen* was a physicist at the University of Würzburg in Germany. Late on Friday, 8 November, 1895, he was doing an experiment in his laboratory when he noticed something extraordinary. He had covered an electric bulb with black cardboard, and when he switched on the current he saw little dancing lights on his table. Now the bulb was completely covered; how then could any ray penetrate? On the table there were some pieces of paper which had been covered with metal salts. It was on this paper that the lights were shining. Professor Röntgen took a piece of this paper and held it at a distance from the lamp. Between it and the lamp he placed a number of objects, a book, a pack of cards, a piece of wood and a doorkey. The ray penetrated every one of them except the key. This mysterious ray could shine through everything except the metal. He called his wife into the laboratory and asked her to hold her hand between the lamp and the photographic plate. She was very surprised by this request, but she obediently held up her hand for a quarter of an hour, and when the plate was developed there was a picture of the bones of her hand and of the ring on one finger. The ray could pass through the flesh and not through the bone or the ring.

At a scientific meeting where he described what happened. Professor Röntgen called this new ray "the Unknown", the X-ray. Doctors quickly saw how this could be used, and soon there were X-ray machines in all the big hospitals. At first the doctors did not understand how powerful the rays were and many of them were injured, losing a finger or an arm through exposure to X-rays when they were using the machines. The most obvious use for this discovery was to make it possible for doctors and surgeons to see exactly how a bone was fractured. Other uses came later. It was found that these rays could be used to destroy cancer cells, just as they destroyed the healthy cells of the doctors who first used the machine. Methods were found later by which "ulcers in the stomach could be located, and the lungs could be X-rayed to show if there was any tuberculosis present. "Mass X-ray" units are sent round to factories and detect early signs of trouble in the lungs.

Unfortunately for Professor Röntgen, whose discovery did so much for medical science, envious colleagues spread the story that he had stolen his discovery from a laboratory assistant who worked for him. He died, poor and forgotten, in 1923.

(After "Britain in the Modern World, The Twentieth Century" by E. N. Nash and A. M. Newth)

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