[Footnote 162: _De Facie in Orbe Lunæ_, xix., 10. Cf. Grant, _Astr. Nach._, No. 1838. As to the phenomenon mentioned by Philostratus in his _Life of Apollonius_ (viii. 23), see W. T. Lynn, _Observatory_, vol. ix., p. 128.] [Footnote 163: Schmidt, _Astr. Nach._, No. 1832.] [Footnote 164: _Astronomiæ Pars Optica, Op. omnia_, t. ii., p. 317.] [Footnote 165: _De Stellâ Novâ, Op._, t. ii., pp. 696, 697.] [Footnote 166: _Astr. Pars Op._, p. 320.] [Footnote 167: _Mém. de l'Ac. des Sciences_, 1706, p. 119.] [Footnote 168: A digit = 1/12 of the solar diameter.] [Footnote 169: _Phil. Trans._, vol. xxix., pp. 247-249.] [Footnote 170: _Mém. de l'Ac. des Sciences_, 1715; _Histoire_, p. 49; _Mémoires_, pp. 93-98.] [Footnote 171: _Ibid._, 1724, p. 178.] [Footnote 172: _Mém. de l'Ac. des Sciences_, 1715, pp. 161, 166-169.] [Footnote 173: _Ed. Ency._, art. _Astronomy_, p. 635.] [Footnote 174: _Trans. Am. Phil. Soc._, vol. vi., p. 274.] [Footnote 175: _Memoir of Caroline Herschel_, p. 327.] [Footnote 176: _Phil. Trans._, vol. xxv., p. 2240.] [Footnote 177: _Ibid._, vol. xl., p. 182.] [Footnote 178: _Ibid._, vol. xlv., p. 586.] [Footnote 179: _Mem. R. A. S._, vol. i., pp. 145, 148.] [Footnote 180: _American Journal of Science_, vol. xlii., p. 396.] [Footnote 181: _Phil. Trans._, vol. xxxviii., p. 134. Father Secchi, however, adverted to a distinct mention of a prominence observed in 1239 A.D. A description of a total eclipse of that date includes the remark, "Et quoddam foramen erat ignitum in circulo solis ex parte inferiore" (Muratori, _Rer. It. Scriptores_, t. xiv., col. 1097). The "circulus solis" of course signifies the corona.] [Footnote 182: _Phil. Trans._, vol. lxix., p. 114.] [Footnote 183: _Trans. Am. Phil. Soc._, vol. vi., 1809, p. 267.] [Footnote 184: _Annuaire_, 1846, p. 460.] [Footnote 185: _Ibid._, p. 439, _note_.] [Footnote 186: _Ibid._, p. 416.] [Footnote 187: _Mem. R. A. S._, vol. xxi., p. 82.] [Footnote 188: _Ibid._, p. 90.] [Footnote 189: _Ibid._, pp. 7, 8.] [Footnote 190: _Le Soleil_, t. i., p. 386.] [Footnote 191: By Williams and Stanistreet, _Mem. R. A. S._, vol. xxi., pp. 54, 56. Santini had made a similar observation at Padua in 1842. Grant, _Hist. Astr._, p. 401.] [Footnote 192: Lassell in _Month. Not._, vol. xii., p. 53.] [Footnote 193: _Comptes Rendus_, t. xxxiv., p. 155.] [Footnote 194: _Optische Untersuchungen_, and _Zeitschrift für populäre Mittheilungen_, Bd. i., 1860, p. 201.] CHAPTER IV _PLANETARY DISCOVERIES_