1. E. C. Kemble and E. Hill, Proc. N. A. S., 15, 387; 1929. F. Rasetti, ibid. 15, 515; 1929.
2. F. Rasetti, Phys. Rev., 34, 367; 1929.
3. J. Cabannes and P. Daure, C. R., 186, 1533; 1928. A shift of 0.01 A. for butane vapour at normal pressure.
4. P. Daure, Thèse, Paris, 1928. Shift of 100 cm.'1 for the missing line in liquid hydrogen chloride and of 20 cm.'1 for the Q-branch at 3 in liquid ammonia.
5. C. V. Raman and K. S. Krishnan, Proc. Roy. Soc., A, 122, 23; 1928.