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X rays.

Work on cathode rays by Goldstein (see 1876) and by Crookes (see 1861) had come to interest a number of physicists in the subject. One of them was a German physicist, Wilhelm Conrad Rontgen (1845-1923), who was particularly interested in the ability of cathode rays to make materials fluoresce.

He placed certain chemicals, known to fluoresce easily, inside a cathode ray tube, surrounded it by dark paper, and darkened the room to observe the pale fluorescence that would result.

On November 5, 1895, he set his cathode-ray tube to working, and in the dimness, a flash of light that did not come from the tube caught his eye. A sheet of paper coated with barium platinocyanide (one of the chemicals he was planning to use) was glowing. The glow ceased when the cathode-ray tube was turned off. The coated paper glowed even in the next room once the cathode-ray tube was turned on.

Radiation was clearly emerging from the tube when the cathode rays were streaming, and was penetrating matter to some extent. Rontgen didn't know what the radiation might be, so he referred to it as X rays, x being the usual symbol for an unknown quantity in mathematics. He published his findings on December 18, 1895.

The news of these X rays roused the world of physics to a furor not seen since Orsted had discovered electromagnetism (see 1820). So much work was done, and so many revolutionary findings were made (most of them as a direct result of Rontgen's finding) that Rontgen is often viewed as having set off a second Scientific Revolution, as Copernicus had set off the first (see 1543).

For this work, Rontgen received the Nobel Prize in physics (the first one) in 1901.

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Author:Asimov, Isaac
Publication:Asimov's Chronology of Science & Discovery, Updated ed.
Article Type:Reference Source
Date:Jan 1, 1994
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