r; the latter had no hair, but William had received some from the
comet.' This is the only instance, so far as I know, in which a comet
has been regarded as a perruquier. A monk of Malmesbury spoke more to
the purpose, according to then received ideas, in thus apostrophising
the comet: 'Here art thou again, cause of tears to many mothers! It is
long since I saw thee last, but I see thee now more terrible than ever;
thou threatenest my country with complete ruin.'

Halley's comet, with its inconveniently short period of about
seventy-seven years, has repeatedly troubled the nations and been
regarded as a sign sent from Heaven:

Ten million cubic miles of head,
Ten billion leagues of tail,

all provided for the sole purpose of warning one petty race of
earth-folks against the evils likely to be brought against them by
another. This comet has appeared twenty-four times since the date of its
first recorded appearance, which some consider to have been 12 B.C., and
others refer to a few years later. It may be interesting to quote here
Babinet's description of the effects ascribed in 1455 to this comet,
often the terror of nations, but the triumph of mathematicians, as the
first whose motions were brought into recognisable obedience to the laws
of gravity.[42]

'The Mussulmans, with Mahomet II. at their head, were besieging
Belgrade, which was defended by Huniade, surnamed the Exterminator of
the Turks. Halley's comet appeared and the two armies were seized with
equal fear. Pope Calixtus III., himself seized by the general terror,
ordered public prayers and timidly anathematised the comet and the
enemies of Christianity. He established the prayer called the noon
_Angelus_, the use of which is continued in all Catholic churches. The
Franciscans (_Freres Mineurs_) brought 40,000 defenders to Belgrade,
besieged by the conqueror of Constantinople, the destroyer of the
Eastern Empire. At last the battle began; it continued two days without
ceasing. A contest of two days caused 40,000 combatants to bite the
dust. The Franciscans, unarmed, crucifix in hand, were in the front
rank, invoking the papal exorcism against the comet, and turning upon
the enemy that heavenly wrath of which none in those times dared doubt.'

The great comet of 1556 has been regarded as the occasion of the Emperor
Charles V.'s abdication of the imperial throne; a circumstance which
seems rendered a little doubtful by the fact that he had already
ab