X-Rays Or Rontgen Rays
( Originally Published Early 1900's )
X or Rontgen Rays are a newly discovered form of energy that is radiated from a highly exhausted discharge tube, and developed by an electrical discharge. The rays are so called for their discoverer, Prof. IV. C. Rontgen of Wurtzburg, who gave them the name "X rays" because he was ignorant of their precise nature, the letter "X" being the usual algebraic symbol for an unknown quantity. The Rontgen rays resemble ordinary light in being propagated in straight lines, in being capable of reflection, in causing phosphorescence, and in affecting a sensitized plate. They differ from it in being invisible, in not being capable of refraction or polarization, and in being able to traverse many substances that are opaque to ordinary light. The phenomena caused by the passage of electricity through exhausted tubes have long attracted attention. It was noticed by Faraday in 1837, and by Plucker, in 1858, who was the first to cause apparatus to be made whereby a practically permanent vacuum could be maintained in a glass bulb. The physicist Crookes improved the tube and made many experiments with "cathode rays." The discovery of Rontgen was announced in 1896 as a new form of radiation. The discovery was accidental, and was made by observing that a highly flourescent substance with which he was experimenting gave out light whenever a neighboring Crookes tube was excited, though this tube was covered with an opaque cloth. The phenomena differed from cathode rays, and it was found that when the human hand was interposed between the tube and a photo-graphic plate, the new rays caused a marked shadow picture of the skeleton to appear on the plate. Nothing but a shadow picture was possible owing to the fact that the rays are capable of but slight reflection. Extraordinary and widespread interest was at once aroused, but the purely scientific interest was for the time being overshadowed in the public mind by the sensational announcement that a means of "seeing through" the human body had been devised. Notwithstanding these exaggerations, experimenters in all countries verified Prof Rontgen's own claims. The shadow pictures are used for a great variety of purposes, such as locating foreign bodies, examining fractures and malformations of bones, in dental surgery, and in detecting adulterations. The rays have also been utilized in France for the study of fossils.