er really referred to a comet, and they
even regard this comet as an apparition of the comet of 1680. They cite
in support of this opinion the portent which followed the prayer of
Anchises, 'AEneid,' Book II. 692, etc.: 'Scarce had the old man ceased
from praying, when a peal of thunder was heard on the left, and a star,
gliding from the heavens amid the darkness, rushed through space
followed by a long train of light; we saw the star,' says AEneas,
'suspended for a moment above the roof, brighten our home with its
fires, then, tracing out a brilliant course, disappear in the forests of
Ida; then a long train of flame illuminated us, and the place around
reeked with the smell of sulphur. Overcome by these startling portents,
my father arose, invoked the gods, and worshipped the holy star.' It is
impossible to recognise here the description of a comet. The noise, the
trail of light, the visible motion, the smell of sulphur, all correspond
with the fall of a meteorite close by; and doubtless Virgil simply
introduced into the narrative the circumstances of some such phenomenon
which had been witnessed in his own time. To base on such a point the
theory that the comet of 1680 was visible at the time of the fall of
Troy, the date of which is unknown, is venturesome in the extreme. True,
the period calculated for the comet of 1680, when Pingre and Lalande
agreed in this unhappy guess, was 575 years; and if we multiply this
period by five we obtain 2875 years, taking 1680 from which leaves 1195
years B.C., near enough to the supposed date of the capture of Troy.
Unfortunately, Encke (the eminent astronomer to whom we owe that
determination of the sun's distance which for nearly half a century held
its place in our books, but has within the last twenty years been
replaced by a distance three millions of miles less) went over afresh
the calculations of the motions of that famous comet, and found that,
instead of 575 years, the most probable period is about 8814 years. The
difference amounts only to 8239 years; but even this small difference
rather impairs the theory of Lalande and Pingre.[41]

Three hundred and seventy-one years before the Christian era, a comet
appeared which Aristotle (who was a boy at the time) has described.
Diodorus Siculus writes thus respecting it: 'In the first year of the
102d Olympiad, Alcisthenes being Archon of Athens, several prodigies
announced the approaching humiliation of the Lacedaemonians; a bl