[360] Proc. Roy. Soc., 99A, 135, 1921.

[361] M. N. R. A. S., 83, 403, 1923; ibid., 84, 499, 1924.

[362] Russell and Stewart, Ap. J., 59, 197, 1924.

[363] Eder and Valenta, Atlas Typischer Spektren, 10, 1911.

[364] See Chapter V, [p. 69]. A. Fowler, Bakerian Lecture, 1924, designates this an ultimate line.

[365] See Chapter XIII, [p. 185].

[366] Milne, Observatory, 44, 264, 1921.

[367] M. N. R. A. S., 83, 403, 1923; 84, 499, 1924.

[368] Sommerfeld, Atombau und Spektrallinien, 457, 1922.

[369] Meggers, Kiess, and Walters, Journ. Op. Soc. Am., 9, 355, 1924.