[Footnote 601: _Proc. Roy. Soc._, vol. xvii., p. 302.] [Footnote 602: _Astr. Nach._, No. 1,769.] [Footnote 603: _Am. Jour. of Science_, vol. xv., p. 85.] [Footnote 604: _Journ. Franklin Institute_, vol. xl., p. 232_a_.] [Footnote 605: _Pogg. Annalen_, Bd. cxlvi., p. 475; _Astr. Nach._, No. 3,014.] [Footnote 606: _Astr. Nach._, Nos. 3,006, 3,037.] [Footnote 607: This device was suggested by Janssen in 1869.] [Footnote 608: _Astr. and Astrophysics_, vol. xi., pp. 70, 407.] [Footnote 609: _Astr. and Astrophysics_, vol. xi., p. 604.] [Footnote 610: _Comptes Rendus_, t. cxiii., p. 307.] [Footnote 611: _Astr. and Astrophysics_, vol. xi., p. 50.] [Footnote 612: _Ibid._, pp. 60, 314.] [Footnote 613: Wiedemann's _Annalen der Physik_, Bd. xxv., p. 80.] [Footnote 614: Evershed, _Knowledge_, vol. xxi., p. 133.] [Footnote 615: Secchi, _Le Soleil_, t. ii., p. 294.] [Footnote 616: Lockyer, _Chemistry of the Sun_, p. 418.] [Footnote 617: _L'Astronomie_, August, 1884, p. 292 (Riccò); see also Evershed, _Jour. British Astr. Ass._, vol. ii., p. 174.] [Footnote 618: Averaging about 100 miles across and 300 high. _Le Soleil_, t. ii., p. 35.] [Footnote 619: _The Sun_, p. 192.] [Footnote 620: _Astr. Nach._, No. 1,854.] [Footnote 621: _Mem. degli Spettroscopisti Italiani_, t. v., p. 4; Secchi, _ibid._, t. vi., p. 56.] [Footnote 622: Its non-atmospheric character was early defined by Proctor, _Month. Not._, vol. xxxi., p. 196.] [Footnote 623: _Astroph. Jour._, vol. vi., p. 412.] [Footnote 624: _Ibid._, vol. xi., p. 165.] [Footnote 625: _Ibid._, p. 243.] [Footnote 626: _Sun's Place in Nature_, pp. 111, 288.] [Footnote 627: _Abh. d. Kön. Böhm Ges. d. Wiss._, Bd. ii., 1841-42, p. 467.] [Footnote 628: In a paper read before the Société Philomathique de Paris, December 23, 1848, and first published _in extenso_ in _Ann. de Chim. et de Phys._, t. xix., p. 211 (1870). Hippolyte Fizeau died in September, 1896.] [Footnote 629: _Astr. Nach._, No. 1,772.] [Footnote 630: _Ibid._, No. 1,864.] [Footnote 631: A. Cornu, _Sur la Méthode Doppler-Fizeau_, p. D. 23.] [Footnote 632: _Am. Jour. of Sc._, vol. xii., p. 321.] [Footnote 633: _Ibid._, vol. xiv., p. 140.] [Footnote 634: _Bull. Astronom._, February, 1884, p. 77.] [Footnote 635: _Comptes Rendus_, t. xci., p. 368.] [Footnote 636: _Month. Not._, vol. xliv., p. 170.] [Footnote 637: See _ante_, p. 147.] [Footnote 638: _Recherches sur la Rotation du Soleil_, Upsal, 1891.] [Footnote 639: Harzer, _Astr. Nach._, No. 3,026; Stratonoff, _Ibid._, No. 3,344.] [Footnote 640: _Publ. Astr. Pacific Soc._, vol. ii., p. 193.] [Footnote 641: _Proc. Roy. Society_, vols. xvii., p. 415; xviii., p. 120.] [Footnote 642: _Comptes Rendus_, t. cxii., p. 1421; t. cxiii., p. 310.] [Footnote 643: At the sun's distance, one second of arc represents about 450 miles.] [Footnote 644: _Amer. Jour. of Sc._, vol. ii., p. 468, 1871.] [Footnote 645: _Month. Not._, vol. xxxii., p. 51.]