1. Chadwick discovered that the beta spectrum was continuous. L. Meitner suggested in 1922 that a quantized nucleus should not be expected to emit a continuous spectrum, and Ellis found non-conservation of energy from experiments on the emitted electron. Chadwick, J., Verh. Deutsch. Phys. Ges., 16, 383 (1914). Ellis, C. D., Internat. Conf. on Phys., 15, 209 (1934).
2. Ellis and Wooster, Proc. Roy. Soc., A, 117, 109 (1927). Chadwick, J., and Lea, D. E., Proc. Camb. Phil. Soc., 30, 59 (1934); Nahmias, M. E., Proc. Camb. Phil. Soc., 31, 99 (1935). Wu, C. S., Phys. Rev., 59, 481 (1941).
3. Pauli, W., in “Rapports du Septième Conseil de Physique Solvay”, Brussels, 1933 (Gauthier-Villars, Paris, 1934).
4. Fermi, E., Z. Phys., 88, 161 (1934).
5. We do not attempt here to describe the many beautiful and difficult, recoil experiments in which recoils of neutrino-emitting nuclei (∼ 8–200 eV.) have been measured. A summary can be found in an article by O. Kofoed-Hansen in Siegbahn's “Beta and Gamma-Ray Spectroscopy” (Interscience Publishers, Inc., New York, 1955).