[412] Adams and Kohlschütter, Mt. W. Contr. 89, 1914.

[413] B. A. N. 19, 1922.

[414] Milne, Phil. Mag., 47, 209, 1924.

[415] Pannekoek, B. A. N. 19, 1922.

[416] Pop. Ast., 31, 88, 1923.

[417] Pop. Ast., in press.

[418] B. A. N. 19, 1922.

[419] In Pannekoek’s notation, a is surface brightness, is radius, and , surface gravity.

[420] Stewart, Pop. Ast., in press.

[421] Pub. Dom. Ap. Obs., 3, 1, 1924.

[422] P. 121.

[423] H. C. 258, 1924.

[424] Adams, Pub. A. S. P., 28, 278, 1916; Adams and Joy, Pub. A. S. P., 36, 142, 1924.

[425] Pub. Solar Phys. Com., 1910.

[426] Chapter V, p. 81.

[427] Chapter, V, p. 70.

[428] Menzel, H. C. 258, 1924; Chapter VIII, p. 126.