[1] Meddelanden frÅn Lunds Observatorium, No. 41.

[2] Meddelanden frÅn Lunds Astronomiska Observatorium, Serie II, No. 14.

[3] Annals of the Harvard Observatory, vol. 50.

[4] In order to deduce from M the apparent magnitude at a distance corresponding to a parallax of 1 we may subtract 3^m.48. To obtain the magnitude corresponding to a parallax of 0.1 we may add 1.57. The latter distance is chosen by some writers on stellar statistics.

[5] The best colour-scale of the latter sort seems to be that of Osthoff.

[6] Compare H. A. 50 and H. A. 56 and the remarks in L. M. II, 19.

[7] “Bonner Sternverzeichnis” in den Astronomischen Beobachtungen auf der Sternwarte zu Bonn, Dritter bis FÜnfter Band. Bonn 1859-62.

[8] “Bonner Durchmusterung”, Vierte Sektion. Achter Band der Astronomischen Beobachtungen zu Bonn, 1886.

[9] “The Cape Photographic Durchmusterung” by David Gill and J. C. Kapteyn, Annals of the Cape Observatory, vol. III-V (1896-1900).

[10] “Cordoba Durchmusterung” by J. Thome. Results of the National Argentine Observatory, vol. 16, 17, 18, 21 (1894-1914).

[11] Aph. J., vol. 36.

[12] H. A., vol. 71.

[13] H. A., vol. 91, 92, 93, 94.

[14] A catalogue of radial velocities has this year been published by J. Voute, embracing 2071 stars. “First catalogue of radial velocities”, by J. Voute. Weltevreden, 1920.

[15] Compare Adams' memoirs in the Contributions from Mount Wilson.

[16] The first line gives the stars of an absolute magnitude between -4.9 and -4.0, the second those between -3.9 and -3.0, &c. The stars of type B and A are from Walkey's catalogue.