[689] Phil. Trans., vol. clxx., p. 46.
[690] Comptes Rendus, t. xcvii., p. 555; t. ci., p. 1145.
[691] Liveing and Dewar, Astr. and Astrophysics, vol. xi., p. 705.
[692] Comptes Rendus, t. lx., p. 213; t. lxiii., p. 289.
[693] Ibid., t. cviii., p. 1035.
[694] Ibid., t. cxi., p. 431.
[695] Astroph. Jour., vols. iv., p. 317; vi., p. 426.
[696] Trans. Roy. Soc. Edin., vol. xxxii., p. 452.
[697] Comptes Rendus, t. cxi., p. 941; Huggins, Proc. Roy. Soc., vol. xlvi., p. 168.