. It may further be remarked that Poincaré (Journ. d. Physique, ii. p. 5 (1912)) has deduced the necessity of assuming that the transference of energy takes place in quanta
in order to explain the experimental laws of black radiation.
[6] A series of lines, first observed by Pickering in stellar spectra and recently by Fowler in vacuum-tubes containing a mixture of hydrogen and helium, is generally also ascribed to hydrogen. These lines, however, can be accounted for on the present theory, if we ascribe them to helium. (Phil. Mag. loc. cit. p. 10: comp. also ‘Nature’ xcii. p. 231 (1913).)
[7] Comp. A. v. d. Broek, Phys. Zeitschr. xiv. p. 32 (1913), comp. also several recent contributions to ‘Nature.’
[8] Phil. Mag. loc. cit. p. 487.
[9] Comp. J. W. Nicholson, Month. Not. Roy. Astr. Soc. lxxii. p. 679 (1912).
[10] Note added during the proof.—In the Phys. Zeitschr. of Feb. 1, E. Gehrcke has attempted to represent the theory of the hydrogen spectrum in a way somewhat different from that in my former paper. Like the procedure in my paper, Gehrcke does not attempt to give a mechanical explanation of Planck’s relation between the frequency of the radiation and the amount of energy emitted; but he does also not try to give a mechanical interpretation of the dynamical equilibrium of the atom in its possible stationary states, or to obtain a connexion to ordinary mechanics in the region of slow vibrations.
[11] Note added during the proof—In the Phys. Zeitsehr. of Feb. 1, A. Garbasso and E. Gehrcke (c. f. note, p. 6) have deduced expressions for