RECENT RESEARCH ON RADIOACTIVITY.
By P. CURIE.
[Reprinted from the American Chemical Journal, Vol. XXXI, No. 4. April, 1904.]
RECENT RESEARCH ON RADIOACTIVITY.[1]
By P. Curie.
Since the discovery of strongly radioactive substances, research on radioactivity has been greatly developed. I propose in this article to give an account of the actual state of our knowledge relative to this subject, laying particular stress on the most recent work.[2]
[1]Translated from an article that appeared in Jour. d. Chim. Phys., I, 409 (1903) edited by Philippe A. Guye, Professor of Chemistry in the University of Geneva. See THIS JOURNAL, 31, 298 (1904).
[2]For more complete details of work done previous to May, 1903, see the thesis of Mme. Curie. It appeared in Ann. de Chim. et de Phys. in 1903 and 1904.
I. Radioactive Substances.
Becquerel Rays. Uranium and Thorium.—We call radioactive such substances as are capable of emitting spontaneously and continuously certain rays known as Becquerel rays. These rays act upon the photographic plate; they render the gases through which they pass conductors of electricity; they can pass through black paper and metals. The Becquerel rays cannot be reflected, refracted or polarized.