Author_Institution :
Bell Telephone Laboratories, Inc., New York, N. Y.
Abstract :
In a very few years after its discovery in 1898, radioactivity became and has ever since remained the most celebrated subdivision of modern physics. In addition to substances naturally radioactive, such as radium, others may be made so artificially; in fact, of all the known elements, hydrogen alone remains the only one of which a radioactive type has not been discovered or invented.
