Recherches sur les substances radioactives
Marie Sklodowska Curie(1867-1934)
 It was Becquerel who first noticed that the residuum of pitchblende from which uranium was extracted showed an intensity of radioactivity four times greater than uranium itself. He suggested to Marie Curie, his pupil and friend at that time, that she investigate the pitchblende. Curie immediately undertook the research with the collaboration of her husband Pierre, and succeeded in June 1898 in separating from pitchblende a new element with a radioactive intensity three hundred times greater than uranium, which she named polonium after her native country Poland. However, even after the uranium and polonium were extracted, the residuum still maintained radioactive intensity.
 The Curie’s continued further investigation and in December 1898 finally discovered another substance, a new element that had a radioactive intensity a million times greater than uranium. They called it radium and determined its atomic weight to be 226.2. With hard, painful work during the following years, they extracted a decigram of pure radium from several tons of pitchblende in 1902.
 In addition to that Curie also made the first measurement of radioactive radiation through the application of the Piezo electric effect discovered by her husband. Like Rutherford, Curie enunciated the atomic nature of radioactivity as a characterization of alpha rays, a demonstration of equivalence between election and beta rays and was the distinction of gamma rays.
 In 1903, Curie wrote the above dissertation in which she compiled all the above mentioned research during her most creative period, 1897-1903, in a detailed, critical presentation. This dissertation was also her first integrated and correlated examination that included all of her studies. In it Curie described the enormous amounts of energy emitted by radium, which Einstein was able to formulate as the equivalence of mass and energy (E=mc2) three years later. Curie not only clarified the chemical aspects of radioactivity, but also prepared and opened up a new realm of nuclear physics. With these contributions and this treatise. Marie Curie was awarded the Nobel Prize together with Becquerel and her husband Pierre Curie in the same year.