In 1907, I received a precious mark of sympathy from Mr. Andrew Carnegie, who donated to my laboratory an annual income for research fellowships which enabled some advanced students or scientists to devote their whole time to investigation. Such foundations are very encouraging to those whose inclinations and talents are such as to warrant their entire devotion to research work. They ought to be multiplied in the interest of science. As for myself, I had to devote again a great deal of time to the preparation of several decigrammes of very pure radium chloride. With this I achieved, in 1907, a new determination of the atomic weight of radium, and in 1910 I was able to isolate the metal. The operation, an extremely delicate one, was performed with the assistance of a distinguished chemist belonging to the laboratory staff. It has never been repeated since that time, because it involves a serious danger of loss of radium, which can be avoided only with utmost care. So I saw at last the mysterious white metal, but could not keep it in this state, for it was required for further experiments. As for the polonium, I have not been able to isolate it, its quantity in the mineral being even much less than the quantity of radium. However, very concentrated polonium has been prepared in my laboratory, and important experiments have been performed with this substance, concerning especially the production of helium by radiation of polonium. I had to devote special care to the improvement of the measuring methods in the laboratory. I have told how important precise measurements were in the discovery of radium. It is still to be hoped that efficient methods of quantitative determination may lead to new discoveries. I devised a very satisfactory method for determining the quantity of radium by the means of a radioactive gas produced by it and called "emanation." This method, frequently used in my laboratory, permits of the measurement of very small quantities of radium (less than a thousandth of a milligramme), with a fair precision. More important quantities are often measured by their penetrating radiation, named Gamma-rays. For this we also possess in my laboratory a suitable equipment. It is easier and more satisfactory to measure the radium by the emitted rays, than to weigh it in a balance. However, these measurements require the disposition of reliable standards. So the question of a radium standard had to be taken into careful consideration. The measurements of radium had to be established on a solid basis, for the benefit of laboratories and scientific research, which, of course, is in itself an important reason, and moreover, the growing medical utilization of this substance made it necessary to control the relative purity of commercially produced radium.