Note 160 — Chapter VI

Mme. Curie, in an article which she wrote shortly after her discovery of radium, shows that she possesses a genius for inductive science of the highest type. "It was at the close of the year 1897," she writes, "that I began to study the compounds of uranium, the properties of which had greatly attracted my interest. Here was a substance emitting spontaneously and continually radiations similar to Röntgen rays, whereas ordinarily, Röntgen rays can be produced only in a vacuum tube with the expenditure of electrical energy. By what process can uranium furnish the same rays without expenditure of energy and without undergoing apparent modification? Is uranium the only body whose compounds emit similar rays? Such were the questions I asked myself; and it was while seeking to answer them that I entered into the researches which have led to the discovery of radium." Radium and Radio-Activity in The Century Magazine, for January, 1904.