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Wilhelm Roentgen

     Professor Wilhelm Roentgen was fascinated by the mysterious illumination  produced by an electric discharge in a tube without any air. The illumination seemed to start at the negative electrode, or "cathode". Accordingly, the phenomenon was referred to as "cathode rays". When the rays hit the glass of the tube, it glowed with a greenish light.
    On November 5, 1895, Roentgen enclosed his cathode ray tube in a box of black cardboard and darkened the room. He wanted to observe the luminescence without the interference of outside light.
     He turned on the electricity. Almost at once a flash of light that did not come from the tube caught his eye. He looked up. Quite a distance from the tube, he happened to have a sheet of paper coated with a chemical, barium platinocyanide. He had been using the paper in experiments because this was one of the chemicals that glowed when placed near the cathode ray tube.


       But wny should it be glowing now? After all, the tube was in a cardboard box!
Roentgen walked into the next room with the coated paper, closed the door, and pulled down the blinds. Still the paper continued the glow so long as the tube was in operation.
      He had discovered something invisible that acted through cardboard and walls!
      Wilhelm Roentgen was born on March 27, 1845, in Lennep, a small town in Germany. For most of his early life, however, he lived outside Germany. He received his primary education in Holland and went to college in Switzerland.
      After completing his college course, Roentgen continued his studies in Switzerland, concentrating on research in physics. In 1888 a new institute of physics was opened at the University of Wurzburg in Bavaria, and Roentgen was invited there. It was there that he discovered his penetrating rays and won world fame.
     His mysterious rays, which penetrated cardboard and doors, causing chemicals to luminesce, were called "Roentgen rays" in honour of their discoverer.
    Roentgen himself, in view of their mysterious origin, .   gave his  rays  the mathematical   symbol  for  the  unknown. He called them "X-rays", the name by which they are commonly referred to in English.
     As we have seen in previous chapters of this book, careful investigations of some phenomenon often result in   unexpected   discoveries   of   related,   but   previously unknown phenomena. To an outsider such discoveries often   seem   accidents  or   luck.   But,   as   Pasteur  once remarked,  in   science   chance   favours   the   prepared mind. The mind  must  be prepared  in  two ways.   It must know the   subject   very   well,   well   enough   to recognize something new when  it  turns  up.   But   it must also be receptive to something new or strange. There is only a narrow line between the understand­able refusal of a scientist to be distracted by side effects and a willingness to notice and to investigate a strange or annoying effect in an experiment. In the last decades of the nineteenth century there were many scientists with more or less "prepared minds" working with  cathode  rays.   But   the  astonishing  discovery  of X-rays  was  made  by a  man  both  lucky  and  wise -lucky enough to observe something peculiar (although oihers had already observed  it)   and wise enough to investigate it.
    When Roentgen announced his discovery, the scien­tific world was amazed. A number of scientists found that they had encountered these mysterious rays earlier. William Crookes, a British scientist who had worked with cathode rays, had noticed several times that photographic film nearby had become fogged." He had thought it accidental and paid no attention. In 1890 A. Goodspeed, an American physicist, had actually   produced what we now call an X-ray photograph, but he was not sufficiently interested to follow it up and  establish the nature of the phenomenon.
     Within a few weeks of his discovery, Roentgen was -able to establish many important characteristics of X-rays. He demonstrated that X-rays have a much  greater penetrating power than cathode rays and that they are not bent by magnetic or electric fields.
     Usually years or even decades pass between a new scientific discovery and its practical application. But with X-rays the applications came quickly. Roentgen's discovery was made in November, 1895. His first publication on the subject appeared in December. And al­ready in January, 1896, the broken arm of an American, Edward McCarthy, was set with the help of X-rays. Soon X-rays were in common use in medical practice. Doctors now had a way of looking into the human body quickly, easily, and — above all — without cutting. Small breaks in bones could be discovered, the begin­nings of tuberculosis in the lungs, foreign objects in the stomach  — in short, the doctor had a magic eye at his disposal.
     In industry, too, X-rays have applications. They can detect internal flaws in the structure of metals, flaws that would be invisible otherwise. In chemical research they are used to probe the structure of crystals and of complex molecules, for example, of proteins. In short, Roentgen's discovery provided a new means of making the invisible visible.




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Albert Einstein 

Alexander Fleming

Igor Kurchatov

Poytr Lebedev

Marie Curie

Michael Faraday

Wilhelm Roentgen


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