Radiograph
a picture of an object or objects obtained by means of the Roentgen rays instead of light rays; called also skiagraph. rarily radioactive. These gases are consisting of Gymnomyxa in which the known as emanations. The emanations from actinium lose their activity very quickly, those from thorium more slowly, while those from radium retain their activity about six thousand times as long as those from actinium. By boiling the solution of a radioactive salt, all the emanations contained in it can be removed, but the de-emanated salt gradually regains its power of producing emanations. The emanations behave, in every way, way, as ordinary gases, and can be liquefied by cooling to very low temperatures. The rays emitted are of three kinds, and are known as the A, B, and I rays. They are capable of passing through opaque substances, but their penetrating power varies greatly. A rays are positively charged and have