592.]

[Footnote 574: He died in London, November 20, 1898.]

[Footnote 575: _Bull. Acad. St. Petersbourg_, t. vi., p. 253.]

[Footnote 576: W. H. Wesley, _Phil. Trans._, vol. cxc, p. 204.]

[Footnote 577: _Lick Reports on Eclipse of January 1, 1889_, p. 204.]

[Footnote 578: _Astroph. Jour._, vol. xi., p. 226.]

[Footnote 579: _Observatory_, vol. xxi., p. 157.]

[Footnote 580: _The Indian Eclipse_, 1898, p. 114.]

[Footnote 581: _Science_, June 22, 1900; _Astroph. Jour._, vol. xii., p.
370.]

[Footnote 582: _Ann. der Physik_, Bd. xlviii., p. 528. See also Wood,
_Physical Review_, vol. iv., p. 191, 1896.]

[Footnote 583: _Science_, August 3, 1900.]

[Footnote 584: _Lick Observatory Bulletin_, No. 9.]

[Footnote 585: _Observatory_, vol. xxiv., pp. 321, 375.]

[Footnote 586: _Lick Report on Eclipse of December 22, 1889_, p. 47;
_Month. Not._, vol. l., p. 372.]

[Footnote 587: _Lick Obs. Bull._, No. 9.]

[Footnote 588: _Bull. de l'Acad. St. Petersbourg_, t. iv., p. 289.]

[Footnote 589: _The Solar Corona discussed by Spherical Harmonics_,
Smithsonian Institution, 1889.]

[Footnote 590: Bakerian Lecture, _Proc. Roy. Soc._, vol. xxxix.]

[Footnote 591: _Astr. and Astrophysics_, vol. xi., p. 483.]

[Footnote 592: _Ibid._, vol. xii., p. 804.]

[Footnote 593: _Am. Journ. of Science_, vol. xi., p. 253, 1901.]

[Footnote 594: See Huggins, _Proc. Roy. Soc._, vol. xxxix., p. 108;
Young, _North Am. Review_, February, 1885, p. 179.]

[Footnote 595: Professor W. A. Norton, of Yale College, appears to have
been the earliest formal advocate of the Expulsion Theory of the solar
surroundings, in the second (1845) and later editions of his _Treatise
on Astronomy_.]

CHAPTER IV

_SOLAR SPECTROSCOPY_

The new way struck out by Janssen and Lockyer was at once and eagerly
followed. In every part of Europe, as well as in North America,
observers devoted themselves to the daily study of the chromosphere and
prominences. Foremost among these were Lockyer in England, Zoellner at
Leipzig, Spoerer at Anclam, Young at Hanover, New Hampshire, Secchi and
Respighi at Rome. There were many others, but these names stood out
conspicuously.

The first point to be cleared up was that of chemical composition.
Leisurely measurements verified the presence above the sun's surface of
hydrogen in prodigious volumes, but showed that sodium had nothing to do
with the o