A Popular History of Astronomy During the Nineteenth Century / Fourth Edition

by Agnes M. Clerke

[132] R. Wolf, Die Sonne und ihre Flecken, p. 9. Marius himself, however, seems to have held the Aristotelian terrestrial-exhalation theory of cometary origin. See his curious little tract, Astronomische und Astrologische Beschreibung der Cometen, Nürnberg, 1619.

[133] Phil. Trans., vol. xxvii., p. 274. Umbræ (now called penumbræ) are spaces of half-shadow which usually encircle spots. Faculæ ("little torches," so named by Scheiner) are bright streaks or patches closely associated with spots.

[134] Mém. Ac. Sc., 1776 (pub. 1779), p. 507. D. Cassini, however, first put forward about 1671 the hypothesis alluded to in the text. See Delambre, Hist. de l'Astr. Mod., t. ii., p. 694; and Kosmos, Bd. iii., p. 410.

[135] Phil. Trans., vol. lxiv., part i., pp. 7-11.

[136] Rosa Ursina, lib. iv., p. 507.

[137] R. Wolf, Die Sonne und ihre Flecken, p. 12.

[138] Schellen, Die Spectralanalyse, Bd. ii., p. 56 (3rd ed.).

[139] Phil. Trans., vol. lxiv., p. 20.

[140] Ibid., vol. lxxxv., 1795, p. 63.

[141] Phil. Trans., vol. xci., 1801, p. 303.