FOOTNOTES:
[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 3m.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.
Transcriber's Note: The following corrections have been made to the original text.
Page 4: "Terrestial distances" changed to "Terrestrial distances"
Page 9: "we must chose," changed to "we must choose,"
Page 12: "acromasie" changed to "achromatism"
Page 15: "inparticular" changed to "in particular"
"supposing, that" changed to "supposing that"
Page 16: "393.4 mm" changed to "393.4 μμ"
Page 20: "for which stars if" changed to "for which stars it"
Page 22: "sphaerical" changed to "spherical"
Page 23: "principal scource" changed to "principal source"
Page 25: "lense with 15 cm" changed to "lens with 15 cm"
Page 27: "Through the spectroscopie method" changed to "Through the spectroscopic method"
"made to its principal" changed to "made its principal"
"american manner" changed to "American manner"
Page 35: "many tenths of a year" changed to "many tens of years"
Page 38: "same appearence" changed to "same appearance"
Page 47: "red stears" changed to "red stars"
"dispersion in M" changed to "dispersion in M"
Page 49: "smaller the" changed to "smaller than"