On the radio-active minerals

Abstract

As Professor Rutherford and Mr. Soddy have pointed out, the study of radio-active minerals is one of the most promising methods of attacking the problem of the connection between the radio-active elements, and the nature of the ultimate inactive products of their change. For in these substances we have, as it were, a laboratory in which the changes have been in progress for immense periods; there is, therefore, a fair chance of obtaining the ultimate products in measurable quantity. In many cases the life of a product is small in comparison with the age of the mineral. We may then expect to find it present in different minerals in a quantity proportional to the amount of its parent. In this way the connection can be made out. Finally, even when the changes are too slow for equilibrium to have been reached, the constant association of two substances may, none the less, give a valuable clue to their relative position in the series of radio-active products. The present paper is a contribution to this subject. It deals with the amount of uranium, radium, thorium, and helium in the minerals. The uranium in the minerals was determined by the ordinary methods of chemical analysis. The majority of the analyses were made for me by Mr. Kitto, of 31, St. Swithin’s Lane, E. C. Mr. H. J. H. Fenton, F. R. S., has also most kindly helped me with this part of the work.