French physicist (1852–1908) whose experiments with uranium salts led to the discovery of spontaneous radioactivity; for this breakthrough he shared the 1903 Nobel Prize for Physics with Marie and Pierre Curie. Handwritten notes on radioactivity by Henri Becquerel, five pages on three sheets, 9 x 13.75, no date but circa 1903. Significant handwritten notes on radioactivity, chronicling discoveries and work of Pierre Curie, Marie Curie, André-Louis Debierne, Ernest Rutherford, and himself between November 1899 and January 1903. In part (translated): "Curie and Madame Curie. Nov. 6, 1899. Radioactivity communicated by exposure to Ra[dium] rays. Increases with the weather. Tending towards limit. Activity plate. Induced radioactivity decreases quickly then slowly. Asymptotic law…Feb 17 01 Curie ionized liquids…We also looked for how to contained the weakened uranium chloride crystals removed of these solutions; these resumed little by little but the humidity conditions from which we had neglected to remove them made the results irregular. Transformed into oxides this 24 December…Let us add that on December 27 we had put the same quantity of the mixture of uranium chloride and barite chloride which were discussed in two balloons, one closed and the other open. The precipitates of barite sulphide collected gave as calculation measuring activity 0.0718 for the closed balloon and 0.0779 for the balloon open…July 1902. Mr. Rutherford…made an interesting study of the absorption of these Uranium radiations by this block, and which has various reserves, then it mainly attaches to the study of the emanation of Thorium and Radium (noting that the production law…is the same with or without an electric field). He concludes from the absorption that the radiations from Thorium and Radium are identical (effects not as a whole). Dispersion of induced radioactivity. Radiation induced by Tho[rium] loss ½ in 11 hours. For Radium different curves depending on the preparations…Continued emanation of Thor[rium] and Ra[dium] / Emanation (Dorn and not Curie—not aware of the emanation of the radium)." In very good to fine condition, with various edge tears, primarily along the top edge. Accompanied by two related contemporary newspaper clippings from French and German newspapers. A unique scientific manuscript by a pioneering physicist who lent his name to the SI unit for radioactivity, the becquerel (Bq).