248.]

[Footnote 265: _Bull. Astr._, t. vi., pp. 241, 289.]

[Footnote 266: _Etude sur la Theorie des Cometes periodiques. Annales de
l'Observatoire_, t. xx., Paris, 1891.]

[Footnote 267: _Amer. Journ. of Science_, vol. xlii., pp. 183, 482,
1891.]

[Footnote 268: _Observatory_, vol. xiv., p. 194.]

[Footnote 269: _Phil. Trans._, vol. cii., pp. 118-124.]

[Footnote 270: _Ueber den Schweif des grossen Cometen von 1811, Monat.
Corr._, vol. xxv., pp. 3-22. Reprinted by Zoellner. _Ueber die Natur der
Cometen_, pp. 3-15.]

[Footnote 271: _Natur der Cometen_, p. 148.]

[Footnote 272: The subject of a classical memoir by Bessel, published in
1810.]

[Footnote 273: A fresh investigation of its orbit has been published by
N. Herz of Vienna. See _Bull. Astr._, t. ix., p. 427.]

[Footnote 274: _Astr. Jahrbuch_ (Bode's), 1823, p. 134.]

[Footnote 275: Reproduced in Webb's _Celestial Objects_, 4th ed.]

[Footnote 276: _Month. Not._, vol. xxxvi., p. 309.]

[Footnote 277: _Celestial Objects_, p. 40, note.]

[Footnote 278: See Airy's Address, _Mem. R. A. S._, vol. x., p. 376.
Rosenberger calculated no more, though he lived until 1890. W. T. Lynn,
_Observatory_, vol. xiii., p. 125.]

[Footnote 279: Hind, _The Comets_, p. 47.]

[Footnote 280: Arago, _Annuaire_, 1836, p. 228.]

[Footnote 281: _Astr. Nach._, No. 300.]

[Footnote 282: It deserves to be recorded that Robert Hooke drew a very
similar inference from his observations of the comets of 1680 and 1682.
_Month. Not._, vol. xiv., pp. 77-83.]

[Footnote 283: _Briefwechsel zwischen Olbers und Bessel_, Bd. ii., p.
390.]

[Footnote 284: Herschel, _Results_, p. 405.]

[Footnote 285: _Mem. R. A. S._, vol. x., p. 92,]

[Footnote 286: _Results_, p. 401.]

[Footnote 287: Pontecoulant, _Comptes Rendus_, t. lviii., p. 825.]

[Footnote 288: _Annuaire_, 1836, p. 233.]

[Footnote 289: _Cosmos_, vol. i., p. 90, _note_ (Otte's trans.).]

[Footnote 290: Herschel, _Outlines of Astronomy_, p. 399, 9th ed.]

[Footnote 291: _Outlines_, p. 398.]

[Footnote 292: Boguslawski calculated that it extended on the 21st of
March to 581 millions.--_Report. Brit. Ass._, 1845, p. 89.]

[Footnote 293: _Comptes Rendus_, t. xvi., p. 919.]

[Footnote 294: _Observatory_, vol. xxiv., p. 167; Astr. Nach., No.
3,320.]

[Footnote 295: Piazzi noticed a considerable increase of lustre in a
very faint star of the twelfth magnitude viewed through a comet. Maedler,
_Reden_, etc., p. 248, _