ROEBUCK 



5048 



ROENTGEN RAYS 



THE ROEBUCK 



in Love with H^ H /. is another of hi- 

 known stories. 



ROEBUCK, ro'buk, also called ROE DEEU ami 

 ROE, a European member of the doer family, 

 one of the smallest of that race. It is a grace- 

 ful, agile animal, 

 with a long neck, 

 slender legs and 

 a very short tail. 

 .:nmcr coat 

 is fox-red above 

 and white be- 

 neath.but in win- 

 ter this changes 

 to a grayish-fawn 

 color, with a white 

 mark on the 

 rump. The male 

 is about twenty- 

 seven inches high 

 at the shoulder, 

 and has upright 

 antlers with two 

 main forks. Roe deer are still found wild in 

 sparsely-settled regions in the temperate parts 

 of Europe, but are far less abundant than for- 

 merly. Both males and females are called roes. 



ROENTGEN, runt' gen, WILHELM KONRAD 

 (1845- ), a German physicist and inventor, 

 born at Lennep, Prussia. He studied at Zurich 

 and Utrecht, became assistant professor at 

 Strassburg in 1873, and was then professor suc- 

 cessively at Hohenheim, Giessem, Wurzburg 

 and Munich. His fame rests on his discovery 

 at Wurzburg, in 1895, of Roentgen rays (which 

 see), commonly known as X-rays, which have 

 practically revolutionized surgery. For this dis- 

 covery he was given the Order of the Royal 

 Crown by the German emperor and the title of 

 baron by Prince Ludwig of Bavaria. In 1900 

 Columbia University awarded him the Barnard 

 Medal for the greatest discovery in science 

 during the preceding five years. He was also 

 awarded the Rumford Medal of the Royal So- 

 ciety of London. 



ROENTGEN RAYS, or X-RAYS, the name 

 given a peculiar radiation discovered in 1895 

 by Professor Wilhelm Roentgen, of the Univer- 

 sity of Wurzburg, while he was experimenting 

 with Crookes tubes. Roentgen gave the name 

 X-rays to these radiations because he did not 

 understand their mechanism. They were after- 

 wards named Roentgen rays, in honor of the 

 discoverer. 



The apparatus for producing Roentgen rays 

 consists of a glass bulb in which nearly a per- 



fect vacuum has been produced, and having a 

 concave cathode (negative) metallic plate (a in 

 illustration) and a flat platinum anode (posi- 

 tive) plate (b) placed at the focus of the con- 

 cave plate and inclined to it at an angle of 45. 

 When a strong electric current is passed through 

 the bulb the cathode rays fall upon the plati- 

 num plate, and from this plate the Roentgen 

 rays pass through the walls of the bulb. 



X-rays are invisible, and can be detected only 

 by their effects. They are not reflected, re- 

 fracted or polarized like ordinary rays of light. 

 They possess the remarkable power of passing 

 through many substances that are opaque to 

 light rays, and of being absorbed by certain 

 transparent substances. They will not, for in- 

 stance, pass through glass, but will pass through 

 muscular tissue. For this reason their discov- 

 ery has revolutionized surgery. Compounds- of 

 borium, calcium and platinum become self- 

 luminous when exposed to X-rays, and if an 

 object opaque to these rays is placed between 

 a screen coated with one of these substances 

 and an X-ray tube, its shadow will appear on 

 the screen. Since the bones absorb more of 

 the rays than the flesh the shadow of the hand 

 thrown upon the screen shows the bones. 



Uses of X-Rays. An X-ray photograph is 

 made by laying the object on the sensitized 

 surface of a photographic plate and exposing 

 the plate to the rays. Surgeons make use of 



X-rays for locating foreign objects, such as 

 needles and bullets, that have penetrated the 

 body, and for determining the character of 

 fractures and dislocations. X-rays are also em- 

 ployed in the treatment of certain forms of 

 cancer. Sometimes physicians employ X-my 

 apparatus for observing the beating of the 

 heart. When the skin is exposed too long to 

 the rays they produce an effect similar to a 

 burn. The apparatus should therefore be used 

 only by experienced operators. 



Consult Williams' The Roentgen Rays in Medi- 

 cine and Surgery ; Thompson's Light, Visible and 

 Invisible; Bragg' s X-Rays: How to Produce and 

 Interpret Them. 



Related Subjects. The reader is referred to 

 the following articles in these volumes : 

 Cancer Roentgen, Wilhelm 



Cathode Rays Konrad 



Crookes Tubes 



