trial Magnetism_, Washington,
1898, p. 27.]

[Footnote 483: _Astr. and Astrophysics_, vol. xi., p. 611.]

[Footnote 484: _Ibid._, p. 819 (Sidgreaves).]

[Footnote 485: See J. Rand Capron, _Phil. Mag._, vol. xv., p. 318.]

[Footnote 486: _Mittheilungen ueber die Sonnenflecken_, No. ix.,
_Vierteljahrsschrift der Naturforschenden Gesellschaft in Zurich_,
Jahrgang 4.]

[Footnote 487: _Mitth._, No. lii., p. 58 (1881).]

[Footnote 488: _Ibid._, No. xii., p. 192. Baxendell, of Manchester,
reached independently a similar conclusion. See _Month. Not._, vol.
xxi., p. 141.]

[Footnote 489: Wolf, _Mitth._, No. xv., p. 107, etc. Olmsted, following
Hansteen, had already, in 1856, sought to establish an auroral period of
sixty-five years. _Smithsonian Contributions_, vol. viii., p. 37.]

[Footnote 490: Hahn, _Ueber die Reziehungen der Sonnenfleckenperiode zu
meteorologischen Erscheinungen_, p. 99 (1877).]

[Footnote 491: _Report Brit. Ass._, 1881, p. 518; 1883, p. 418.]

[Footnote 492: The Rev. A. Cortie (_Month. Not._, vol. lx., p. 538)
detects the influence of a short subsidiary cycle, Dr. W. J. S. Lockyer
that of a thirty-five year period (_Nature_, June 20, 1901). Professor
Newcomb (_Astroph. Jour._, vol. xiii., p. 11) considers that solar
activity oscillates uniformly in 11.13 years, with superposed periodic
variations.]

[Footnote 493: _Opere_, t. iii., p. 412.]

[Footnote 494: _Mitth._, Nos. vii. and xviii.]

[Footnote 495: _Observations at Redhill_, p. 248.]

[Footnote 496: _Comptes Rendus_, t. xcv., p. 1249.]

[Footnote 497: _Ibid._, t. xciii., p. 827; t. xcvi., p. 1418.]

[Footnote 498: _Ibid._, t. c, p. 593.]

[Footnote 499: Ellis, _Proc. Roy. Society_, vol. lxiii., p. 70.]

[Footnote 500: Schultz, _Astr. Nach._, Nos. 2,817-18, 2,847-8; Wilsing,
_Ibid._, No. 3,039; Belopolsky, _Ibid._, No. 2,722.]

[Footnote 501: _Report Brit. Ass._, 1892, p. 635.]

[Footnote 502: A. W. Augur, _Astroph. Jour._, vol. xiii., p. 346.]

[Footnote 503: _Report Brit. Ass._, 1862, p. 16 (pt. ii.).]

[Footnote 504: _Mem. R. A. S._, vol. xxi., p. 161.]

[Footnote 505: _Month. Not._, vol. xxiv., p. 162.]

[Footnote 506: _Am. Jour. of Science_, vol. vii., 1874, p. 92.]

[Footnote 507: Young, _The Sun_, p. 103.]

[Footnote 508: _Ann. Bur. Long._, 1879, p. 679.]

[Footnote 509: _Ibid._, 1878, p. 689.]

[Footnote 510: _Himmelsphotographie_, p. 273.]

[Footnote 511: Ranyard, _Knowledge_, vols. xiv., p. 14, xvi., p. 189;