The Origin of Radium

Abstract

EIGHT months have elapsed since I wrote in your columns (NATURE, May 12, 1904) giving an account of some experiments designed to test the view advanced by Prof. Rutherford and myself that radium is a product of the radio-active change of uranium. I then stated that in 1 kilogram of uranium nitrate that had been under observation over a period of one year since it was completely freed from radium, the quantity of radium reproduced in that time was less than one-ten-thousandth of the quantity theoretically to be expected. This result has been widely quoted, more widely, perhaps, than I intended, for the result was a preliminary conclusion only, and, as I pointed out, obtained under very unfavourable conditions owing to the very powerful preparations of radium that had been in use in the laboratory for other researches. The necessity for publishing it was to a certain extent forced upon me by the attention the problem was beginning to attract from other investigators, and by the prospect of several months' absence abroad. I relied on the fact that the result being negative, the presence of the radium in the laboratory could have had no effect, but in this I was mistaken.