[3] Mr. J.E. Gore in Concise Knowledge Astronomy, pp. 541-2.
[4] Nature, October 26, 1899.
[5] The System of the Stars, p. 385.
[6] This account of Professor Kapteyn's research is taken from an article by Miss A.M. Clerke in Knowledge, April 1893.
[7] The Stars, p. 256. The region here referred to is that where the Milky Way has its greatest width (though nearly as wide in the part exactly opposite), and where it may perhaps extend somewhat in our direction. Miss A.M. Clerke informs me that in April 1901 Kapteyn withdrew the conclusions arrived at in 1893, as being founded on illegitimate reasoning as to the relation of parallaxes to proper motions. But as this relation is still accepted, under certain limitations, by Professor Newcomb and other astronomers, who have arrived independently at very similar results, it seems not improbable that, after all, Professor Kapteyn's conclusions may not require very much modification. Professor Newcomb also tells us (The Stars, p. 214, footnote) that he has seen the latest of Professor Kapteyn's papers, down to 1901; but he does not therefore express any doubt as to his own conclusions as here referred to.
[8] See Knowledge and The Fortnightly Review of April 1903.
[9] Sir R. Ball in an article in Good Words (April 1903) says that luminosity is an exceptional phenomenon in nature, and that luminous stars are but the glow-worms and fire-flies of the universe, as compared with the myriads of other animals.
[10] The Astrophysical Journal, vol. xiv., July 1901, p. 17.
[11] Professor F.J. Allen: What is Life?
[12] Art. 'Vegetable Physiology' in Chambers's Encyclopædia.