Although, as a rule, the tails of comets increase in magnitude and
brilliancy in the vicinity of the sun, and are directed away from that
central body, yet the comet of 1823 offered the remarkable example of two
tails, one of which was turned toward the sun, and the other away from it,
forming with each other an angle of 160 degrees. Modifications of polarity
and the unequal manner of its distribution, and of the direction in which it
is conducted, may in this rare instance have occasioned a double, unchecked,
continuous emanation of nebulous matter.*
[footnote] *Bessel, in 'Astr. Nachr.', 1836, No. 302, s. 231. Schum,
'Jahrb.', 1837 s. 175. See, also Lehmann, 'Ueber Cometenschweife' (On the
Tails of Comets), in Bode, 'Astron. Jahrb. fur' 1826, s. 168.
Aristotle, in his 'Natural Philosophy', makes these emanations the means of
bringing the phenomena of comets into a singular connection with the
existence of the Milky Way. According to his views, the innumerable
quantity of stars which compose this starry zone give out a self-luminous,
incandescent matter. The nebulous belt which separates the different
portions of the vault of heaven was therefore regarded by the Stagirite as a
large comet, the substance of which was incessantly being renewed.
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