[130] Fairfield, H. C. 264, 1924.

[131] H. C. 258, 1924.

[132] Ibid.

[133] Payne, Proc. N. Ac. Sci., 11, 192, 1925; Chapter XIII, [p. 188].

[134] Nature, 114, 86, 1924.

[135] Personal letter.

[136] Chapter IV, [p. 51].

[137] Mt. W. Contr. 262, 1922.

[138] Fairfield, H. C. 264, 1924.

[139] Lindblad, Ap. J., 59, 305, 1924.