Chapter VIII: Book VII: Treating of Comets

I. Phenomena, however wonderful, are not noted and admired
unless they are uncommon. The sun and moon and starry
heavens have no observers, but a Comet at once sets the
whole world agog. The nature of the stars is a sublime and
likewise a profitable study 271

II. The nature of _Comets_ has not been hitherto fully
investigated. They are so rare that one wants a record of
the movements of all ever observed 273

III. Democritus, Eudoxus, Conon, Epigenes, and Apollonius of
Myndus all fail to give any satisfactory account of the
matter. Nor had the Egyptians or Chaldaeans investigated
them 274

IV. Epigenes explains the Comet as due to a conjunction of
Saturn with Mars or the Sun: it is akin to whirlwind and
“beam” meteors 275

V. But there are essential differences between whirlwind, which
is terrestrial, and beams and torches, which are above the
clouds. There is a difference of duration also. Beams and
Comets, it is true, have been mistaken for one another. It
was a Comet, according to Aristotle, that appeared before
the destruction of Buris and Helice. The character of the
flame differs in the two forms 276

VI. There are two kinds of Comets, according to Epigenes. They
are produced by air driven up and setting on fire suitable
material above, which takes place every day at the same hour 277

VII. But Comets are not concomitants of winds; there is no
parallelism in the phenomena. The higher ones, which have an
orbit, he attributes to the north wind, but the facts do not
square here either 278

VIII. The course and altitude of Comets render the whirlwind
explanation impossible 279

IX. The force and duration of whirlwinds are similarly
inadequate 280

X. The slowness and steadiness of the Comet could not be
accounted for on this assumption, nor its general behaviour
and shape 281

XI. We must look for some other explanation. Now Comets, it must
be premised, appear in all quarters of the sky. Whatever the
divisions of them made by the Greeks, they are all of one
origin. Some of the ancients thought they were due to the
union of two planets 283

XII. Again the facts do not square. Comets and planets appear
simultaneously. A conjunction is momentary, a Comet lasts
six months sometimes. The planets do not pass much beyond
the ecliptic, but Comets appear in every quarter of the sky.
And there are other objections 284

XIII. Artemidorus thinks the firmament is solid and has
openings for stars. Comets are casual planets, or formed by
conjunctions of them. His account is a tissue of barefaced
falsehoods 286

XIV. How would a solid firmament be supported? No feasible
explanation can be offered. Besides, the number of stars is
so great--and they may all be “wanderers” if an indefinite
number is--that there must be innumerable conjunctions of
them, _i.e._ Comets. But, as a matter of fact, Comets are
rare 287

XV. Again the huge Comets of the times of Demetrius and Attalus
would require scores of planetary conjunctions to form them 288

XVI. Ephorus, a mere chronicler, who takes this view, has
nothing to support him. He tries, like others of his set, to
embellish his work by narrating marvels. Why did he not tell
us what the two stars were into which the Comet resolved
itself, as he alleges it did? 289

XVII. Apollonius of Myndus holds the Comet to be a true star
(planet) with an erratic course, visible only when it
approaches the lower part of its orbit. Different colours of
Comets 290

XVIII. But Comets do not wax and wane as they approach and
recede like planets. Nor do their orbits lie within the
ecliptic. Besides, we can see through a Comet but not
through a true star (planet) 291

XIX. Zeno the Stoic thinks the light of converging stars gives
the appearance of a longer star. Others hold modified forms
of the same opinion or analogous views 291

XX. Most of the Stoics hold Comets to be evanescent, and
attribute them to friction of the air. Various phenomena are
analogous 292

XXI. Their methods of accounting for varieties of orbits in
Comets 293

XXII. I do not agree with any School. Reasons 295

XXIII. Further arguments showing difference between fires and
Comets 295

XXIV. There may be many stars in the universe whose paths
have not been traced: Comets are such. No satisfactory
explanation has been given of the mind, but its existence is
not doubted 297

XXV. Comets are not yet fully understood. Many things are in the
same category. A future age will be amazed at our ignorance
of such matters 298

XXVI. Reasons of apparent movements of Comets. The transparence
and shape accounted for 299

XXVII. Parallels to the differences between Comets and other
planets 300

XXVIII. Comets give prognostications, but not of immediate
events or weather 302

XXIX. Denial of heaviness and slowness of Comets 303

XXX. Humility is as becoming in investigators of the nature of
the heavens as in worshippers. God has revealed but a little
of Himself to man 304

XXXI. One cannot be surprised that everything has not yet
been discovered. We must leave something to succeeding
generations. We are not yet fully proficient in vice, though
we have striven so long and hard. We still retain, strange
to say, some traces of manhood 305

XXXII. We are all given up to low pleasures and vices, and
devote our strength to them. Philosophy is kept for wet
days. The old teachers have no successors. In fact, we are
letting go what they discovered. We at best play with truth,
which, as of old, lies at the bottom of the well, and needs
the best efforts of young and old, late and early, to bring
it to light 307

NOTES BY SIR A. GEIKIE 309

TRANSLATOR’S NOTES ON “AIR,” QUOTATIONS, AND GERCKE’S READINGS 344

INDEX 351