[Footnote 73: Sir R. Ball's measurements at Dunsink gave to 61 Cygni a parallax of 0·47"; Professor Pritchard obtained, by photographic determinations, one of 0·43".] [Footnote 74: _Additamentum in Mensuras Micrometricas_, p. 28.] [Footnote 75: Elkin's corrected result (in 1897) for the parallax of Vega is 0·082".] [Footnote 76: _Mem. Roy. Astr. Soc._, vol. xi., p. 61.] [Footnote 77: That numbered 21,185 in Lalande's _Hist. Cél._, found by Argelander to have a proper motion of 4·734", and by Winnecke a parallax of O·511". _Month. Not._, vol. xviii., p. 289.] [Footnote 78: _Fund. Astr._, p. 309.] [Footnote 79: _Mém. Prés. à l'Ac. de St. Pétersb._, t. iii.] [Footnote 80: _Phil. Trans._, vol. cxxxvii., p. 79.] [Footnote 81: _Mem. Roy. Astr. Soc._, vols. xxviii. and xxxii.] [Footnote 82: _Ibid._, vol. xlvii., p. 327.] [Footnote 83: _Mémoires de St. Pétersbourg_, t. xxxv., No. 3, 1887; revised in _Astr. Nach._, Nos. 3,729-30, 1901.] [Footnote 84: _Astronomical Journal_, Nos. 213, 501.] [Footnote 85: _Astr. Nach._, Nos. 2,999, 3,000.] [Footnote 86: _Veröffentlichungen der Grossh. Sternwarte zu Karlsruhe_, Bd. iv., 1892.] [Footnote 87: _Proceedings Amsterdam Acad. of Sciences_, Jan. 27, 1900.] [Footnote 88: _Astr. Jour._, No. 457.] [Footnote 89: _Ibid._, Nos. 276, 497.] [Footnote 90: _Phil. Trans._, vol. xcvi., p. 230.] [Footnote 91: _Mém. Prés. à l'Ac. de St. Pétersbourg_, t. iii., p. 603 (read Feb. 5, 1837).] [Footnote 92: _Die Centralsonne, Astr. Nach._, Nos. 566-567, 1846.] [Footnote 93: Sir J. Herschel, note to _Treatise on Astronomy_, and _Phil. Trans._, vol. cxxiii., part ii., p. 502.] [Footnote 94: The position is (as Sir J. Herschel pointed out, _Outlines of Astronomy_, p. 631, 10th ed.) placed beyond the range of reasonable probability by its remoteness (fully 26°) from the galactic plane.] [Footnote 95: Mädler in _Westermann's Jahrbuch_, 1867, p. 615.] [Footnote 96: Letter from Bessel to Sir J. Herschel, _Month. Not._, vol. vi., p. 139.] [Footnote 97: Wolf, _Gesch. d. Astr._, p. 743, _note_.] [Footnote 98: _Astr. Nach._, Nos. 745-748.] [Footnote 99: _Astr. Jour._, No. 440.] [Footnote 100: Adopting Elkin's revised parallax for Procyon of 0·325".] [Footnote 101: _Astr. Nach._, Nos. 1371-1373.] [Footnote 102: _Ueber die Doppelsterne_, Bericht, 1827, p. 22.] [Footnote 103: _Ueber die Doppelsterne_, Bericht, 1827, p. 25.] [Footnote 104: _Mensuræ Micr._, p. xcix.] [Footnote 105: _Stellarum Fixarum imprimis Duplicium et Multiplicum Positiones Mediæ_, pp. cxc., cciii.] [Footnote 106: For instance, the southern stars, 36A Ophiuchi (itself double) and 30 Scorpii, which are 12' 10" apart. _Ibid._, p. cciii.] [Footnote 107: _Stellarum Fixarum_, etc., p. ccliii.] [Footnote 108: _Études d'Astronomie Stellaire_, 1847, p. 82.] [Footnote 109: _Ibid._, p. 86.] [Footnote 110: See Encke's criticism in _Astr. Nach._, No. 622.] [Footnote 111: _Phil. Trans._, vol. cxiv., part iii., 1824.]