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1932 · rif. 49447 — Paris Gauthier-Villars 1932-33. 4to. No wrappers. In: "Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences" Tome 194 and tome 197. - Tome 194: Nos 381015 a. 25. - Tome 197: No 3. 6 entire issues offered. With titlepages to both volumes. The papers: pp. 273-275 708-711 876-877 a. 1 plate 1229-1232 2208-2211 a. 237-38 tome 197. The issue no 25: pp. 2181-2248 lacks the first leaf no affecting the paper. Titlepages with a faint stamp. First printing of these papers of seminal importance to the evolution of particle physics - the results of these investigations immediately lead the way to the discovery of the neutron.They found that the 'Beryllium radiation' discovered by Bothe and Becker ejected protons from a paraffin target. This discovery was amazing because photons have no mass. However the Joliot-Curies interpreted the results as the action of photons on the hydrogen atoms in paraffin. They used the analogy of the Compton Effect in which photons impinging on a metal surface eject electrons. The trouble was that the electron was 1836 times lighter than the proton and therefore recoiled much more easily than the heavier proton after a collision with a gamma photon. When James Chadwick reported to Lord Rutherford on the Joliot-Curies’ results Lord Rutherford exclaimed "I do not believe it!" Chadwick immediately repeated the experiments at the Cavendish Laboratory in Cambridge England. He not only bombarded the hydrogen atoms in paraffin with the beryllium emissions but also used helium nitrogen and other elements as targets. By comparing the energies of recoiling charged particles from different targets he proved that the beryllium emissions contained a neutral component with a mass approximately equal to that of the proton. He called it the neutron. unknown