The Electronic States of the Helium Molecule.

T. Compton and L. A. Turner, Phil. Mag., 48, 360 (1924); Physic. Rev., 25, 606 (1925); Compton, McCurdy and Turner, Physic. Rev., 24, 608 (1924); etc. 8 E. Hulthen, Nature, Oct. 31, 1925. 9 Dr. Hulth6n has been so kind as to inform the writer that the high-frequency system is much weaker than the low-frequency system in HgH, decidedly weaker in CdH and about equally intense in ZnH. It seems likely that the conditions of excitation play a dominant role, masking the effect of the difference in A priori probabilities of the two excited states. Howson's CdH photographs (Astrophys. J., 36, 291, 1912) agree with Hulth6n's statement. 10 This includes an alteration of his published values4 of 1' and e' for ZnHl (private communication). "1 Cf. E. C. Kemble, J. Opt. Soc. Amer., 12, 1 (1926): footnote on p. 4. 12 R. T. Birge, Physic. Rev., 27, probably Feb., 1926 (Abstracts). 13 W. Lenz, Verh. d. D. Phys. Ges., 31, 632 (1919); H. A. Kramers and W. Pauli, Zeit. Physik, 13, 351 (1923).