ray

(ra) [L. ra’dius spoke]. A line of light or of heat. act: r., a light-ray which produces chemic changes. alpha-r’s, a-rays, those radioactive emanations that have the lowest velocity and penetrating power. They consist of positively charged particles having great velocities, but smal] ma es. They are detlected slightly by a strong electric or magnetic field. They are believed to be atoms of the gas helium. astral r., one of the rays of an astrosphere. Becquerel r’s, rays emitted from uranium. They have the pene~ trating properties of the Réntgen rays, but are capable of being polarized, reflected, and refracted. beta-r’s, §-rays, those radio-active emanations that have a moderate velocity and penetrating power. They are charged with negative electricity and are deflected by a magnet. Blond lot r’s. See n-r's. canal-r’s, rays formed when a discharge is pa ed through a vacuum, tube having a perforated cathode. They consist of positive ions, analogous to alpha-rays. cathode-r’s, rays given off from the cathode of a vacuum tube in which an electric discharge takes place. They consist of negatively charged particles, or ions, and move in a straight line unle deflected by a magnet. By striking on solids they generate Réntgen rays. delta-r's, rays of high penetrating power given off from radium and other radioactive substances. They are waves of motion and not electrically charged particles like the alpha and beta rays. Finsen r's. See Finsen Hight, under light. r.-fungus. Same as aclinomyces. gatnma-r’s, y-rays, those radio-active emanations that have the highest velocity and penetrating power. Gold stein’sr’s, rays formed when x-rays pa through some transparent medium. Called also s-r’s. hertzian r’s, electromagnetic waves in the ether similar to a light-wave, but having a greater wave-length. i-r’s, an alleged form of radiant emanations allied to n-rays, and given off from the brain during certain psychic proce es. Lenard r’s, cathode rays after they ave i ued from a Crookes’ tube through a window of platinum foil. medullary r., any cortical extension of a bundle of tubules from a malpighian pyramid of the kidney. mai- Τ᾿ Β, rays generated by pa ing in can des- cent light through dark-blue gla . n-r’s, non- Juminous rays having a wave length below that of heat and light and above that of electricity. These rays are emitted along with light-rays from ordinary flame, and are also given off by certain bodies, as gla , wood, and rubber, when forcibly compre ed and twisted. The rays have the power of pa ing through platinum, aluminum, tin-foil, gla , gold-leaf, and saline water, but they are arrested by pure water and by lead. They also have the property of increasing the luminosity of light and of producing luminosity in fluorescent and phosphorescent bodies. It has been stated that the rays are emitted by living nerve and muscle. Called also Blond lot r’s. A variety of n-rays (called n’-rays) differs from n-rays in diminishing the luminosity of light and of faintly luminous surfaces. Nieuenglowski’s r’s, luminous rays given out by substances which have been exposed to the sun. para cathodic r’s, rays formed by the impaction of cathode rays against a body (the anticathode) in their path. pr Y., a ray iven off directly from a radio-active substance. mtgen r’s [after W. K. Rontgen, of Wirzburg], a species of energy having the property of penetrating substances that are ordinarily opaque and of affecting an ordinary photographic plate. It is generated by an electric current ed through a Ruhmkorff coil, and thence to a ighly exhausted vacuum tube (Crookes’ tube,