Seneca, Naturales Quaestiones

269


No man is so utterly dull and obtuse, with head i
so bent on earth, as never to lift himself up and rise
with all his soul to the contemplation of the starry
heavens, especially when some fresh wonder shows
a beacon-light in the sky. As long as the ordinary
course of heaven runs on, custom robs it of its real
size. Such is our constitution that objects of daily
occurrence pass us unnoticed even when most
worthy of our admiration. On the other hand, the
sight even of trifling things is attractive if their
appearance is unusual. So this concourse of stars, 2
which paints with beauty the spacious firmament on
high, gathers no concourse of the nation. But
when there is any change in the wonted order,
then all eyes are turned to the sky. The sun has
no observer unless he is in eclipse. No one watches
the moon unless she suffer obscuration. But then
whole cities cry out, groundless superstition drives
every one into panic. And yet how much greater 3
are the ordinary movements of the sun ! He takes,
so to speak, as many steps as there are days, com
pleting the year in his circuit. From the summer
solstice he turns back to the lessening days, from
the solstice he slopes his rays, 1 and gives more

1 There is some corruption in the text, but no probable restoration has
been suggested. From the Latin words it would appear that this clause
is merely an explanation of the previous one, inserted by some officious copyist
and therefore spurious.

271



272 PHYSICAL SCIENCE BK. vn

room to the nights ; he occults the planets ; though
so much larger than the earth he does not burn it up,
but cheers it by his heat, which he so regulates as to
make it alternately more intense and more subdued.
He never fills up with light, nor yet obscures, the

4 moon, except when she is right opposite to him. All
this we allow to pass unnoticed as long as the usual
order is preserved. But if there is any disturbance
or any extraordinary light displayed in the sky, we
gaze at it, ask questions, and point it out to our
neighbours. So natural is it to admire what is
strange rather than what is great.

The same thing holds in regard to comets. If
one of these infrequent fires of unusual shape have
made its appearance, everybody is eager to know
what it is. Blind to all the other celestial bodies,
each asks about the newcomer ; one is not quite sure

5 whether to admire or to fear it. Persons there are
who seek to inspire terror by forecasting its grave
import. And so people keep asking and wishing to
know whether it is a portent or a star. But, by my
honour, no one could embark on a more exalted
study, or master a more useful branch of knowledge
than that which treats of the nature of the stars and
planets. Are they a concentration of flame as our
vision avers, and as the very light that streams from
them, 1 and the heat that descends from them suggest ?

6 Or are their orbs not of flame, but, as it were, solid
bodies of earth that glide through tracts of fire,
and having no light of their own draw thence
their brightness and heat ? That is an opinion that
has been held by great men who have believed
the stars to be compact of hard material, and to be
nourished by fire that is not their own. Flame

1 The common reading, aliis=. others, seems an error for z7/r =



i WONDERS OF NATURE COMETS 273

by itself, they argue, would be dissipated and would
have nothing to hold or to be held by. If it were
merely massed and not attached to a solid body,
the universe would assuredly long since have
scattered it in its impetuous whirl.



II

IN view of this inquiry it will be well to ask i
whether comets are wholly analogous to stars and
planets. They seem to have certain elements
in common with them for example, rising and
setting as well as their general form, although
comets are more scattered, and end in a longer
tail. They are alike, too, in their fiery bright
appearance. So, if all the stars are earthy bodies,
comets must share the same lot. But if the 2
stars are pure fire and nothing else, remaining
for six months at a time unbroken by the rapid
whirl of the universe, then comets, too, may
consist of some rarefied material, which is not
broken up by the constant revolution of the sky.
It will also tend to clear up this point if we
endeavour to ascertain whether the earth stands
still while the universe revolves round it, or
whether the converse is the truth, the universe
standing still while the earth revolves. There
have been persons who made bold to say that
it is we that all unwitting are borne round by
the frame of things, that risings and settings are
not produced by a movement of the heavens, but
that we ourselves rise and set. The subject well 3
deserves our study, if we are to know where we
really stand, whether the abode we have obtained

T



274 PHYSICAL SCIENCE BK. vn

as ours is the most sluggish or the swiftest of
motion, whether God causes all things to revolve
round us or causes us to revolve. Now, for this
it is essential that we have a record of all the
appearances of comets in former times. For, on
account of their infrequency, their orbit cannot
as yet be discovered or examined in detail, to
see whether they observe periodic laws, and
whether some fixed order causes their reappear
ance at the appointed day. Such a development
of astronomy is recent, having been lately intro
duced into Greece.



Ill

1 DEMOCRITUS, the most acute of all the ancient
philosophers, says he suspects there are several
stars whose orbits are erratic. But he has given
neither their number nor their names, as the
motions of the five planets were not in his time
understood. Eudoxus was, in fact, the first to
import from Egypt into Greece the knowledge
of these motions, though he says nothing about
comets. From this it becomes plain that, even
among the Egyptians, the people that bestowed
most care on observation of the sky, the portion
of astronomy that relates to comets had not been

2 worked out. Subsequently Conon, who was himself
a careful investigator, made a record of the sun s
eclipses that had been observed by the Egyptians ;
but he made no mention of comets, though he
would certainly not have omitted anything definite
on the subject that he had learned in Egypt. So
much is certain ; two authors, Epigenes and Apol-
lonius of Myndus, the latter highly skilled in cast-



in CAUSES OF COMETS 275

ing horoscopes, who say that they studied among
the Chaldaeans, are at variance in their accounts.
The latter asserts that comets are placed by the 3
Chaldaeans among the number of the wandering
stars (i.e. planets), and that their orbits have been
determined. Epigenes, on the contrary, asserts that
the Chaldaeans have ascertained nothing regarding
comets, which are thought by them to be fires
produced by a kind of eddy of violently rotating
air.



IV

IN the first place, if it like you, let us set down i
the views of the last-mentioned author and refute
them. He supposes that the planet Saturn has
most influence in determining all motions of the
heavenly bodies. When it presses upon the con
stellations next Mars, or crosses to the neighbour
hood of the moon, or encounters the rays of the
sun, being naturally cold and windy, it contracts
and masses the atmosphere at more than one place.
By and by, if Saturn absorb all the sun s rays, there 2
is thunder and lightning. If he has Mars in
agreement, the lightning is forked. Moreover, he
continues, forked and sheet lightning contain
different materials. Evaporation from water or
other moisture produces only gleams that threaten
but stop short of striking. The hotter and drier
exhalation of the earth forges the bolts of forked
lightning. Beam meteors and torches, which differ 3
from one another only in size, are produced in this
same way. When any ball of air what we call a
whirlwind encloses moist earthy matter, wherever
it rushes it presents the appearance of an extended



276 PHYSICAL SCIENCE BK. viz

line of fire, which lasts just so long as the mass
of air remains, which carries within it the supply of
moist earthy matter.



1 THIS account of Epigenes is a tissue of falsehoods.
To begin with the nearest one, the last, it is not true
that torch and beam meteors are due to the violent
action of a whirlwind. The whirlwind is formed
in the neighbourhood of the earth, and there it runs
its course. This is the reason why it tears up trees
by the roots, and wherever it swoops down it lays
bare the soil, carrying off in the meanwhile woods
and roofs of houses ; as a rule, it is lower than the
clouds, and assuredly never higher. But, on the
contrary, it is the more exalted part of heaven that
displays beam meteors, and so they never intervene
between us and the clouds. Besides, a whirlwind
is borne along more swiftly than any cloud, and

2 rotates as on a pivot. And in addition to this, it
ceases all of a sudden, bursting by its own force.
" Beams," on the contrary, do not run or fly across,
like torches, but remain shining for some time
in the same quarter of the sky. Charimander,
too, in the book he wrote on comets, asserts that
a great and unusual light in the sky of the size
of a large beam was once seen by Anaxagoras,
and continued to shine for a long period. Callis-
thenes puts it on record that a similar appearance
of a trail of fire was observed before the sea

3 swallowed up Buris and Helice. Aristotle says it
was not a "beam," but a comet; the characteristic
dispersion of the fire was not seen at first on
account of its excessive brightness, but, in process



v METEORS AND COMETS 277

of time, when the glare began to die down, it
recovered the distinctive appearance of a comet.
In this fiery phenomenon there were many points
worthy of remark, none more so than this, that,
immediately it shone in the sky, the sea came
over Buris and Helice. Did Aristotle, then, one 4
may ask, believe that not merely that beam but
all beams are comets ? Surely not, for there is
this difference, that beams have their fire continuous,
while in the other bodies it is dispersed. Beams
have a regular flame, not interrupted or dull at
any point, while in the end parts it is condensed,
just like what Callisthenes describes the one to
have been, to which I referred a moment ago.



VI

THERE are, Epigenes goes on to say, two classes i
of comets. One kind sheds its light on all sides
without changing its position ; the other extends a
loose kind of fire in one direction, after the fashion
of hair, and passes through among the stars ; of
the latter kind were the two seen in our own days.
The former variety, with hair on all sides, that
do not move, are usually low down, and arise from
the same causes as beams and torches, that is,
from a distempered thick atmosphere that carries
in it many of the earth s exhalations, both dry and
moist. Air driven out through narrow apertures 2
is capable of setting on fire the atmosphere situated
over it, which is full of elements suitable for feeding
a fire ; and it is able after that to drive it forward
from the clear space, lest from any cause it should
fall back and relax its force. After that, it can rise



278 PHYSICAL SCIENCE BK. vn

again on the next and following days and set fire to
the same spot. As presumptive proof of this, we
see winds return during several days at their set
time. Rain, too, and storms in other forms recur
3 according to appointment. His opinion may be
briefly expressed by saying that he supposes comets
to be formed pretty much in the same way as fires
excited by whirlwind. There is this one difference,
that those whirlwinds are pressed down to earth
from a higher region, while these others are raised
from earth to the upper regions.



VII

A GREAT deal can be urged against this view. First
of all, if wind were responsible, a comet would never
make its appearance without wind. As a matter of
fact, it appears when the air is perfectly still. In
the next place, if it were due to wind, it would
fall with the wind ; and if it began through wind,
would increase with increase of wind, and would be
the brighter the more furious the wind was. This
point, too, has to be added to the foregoing : while
the wind impels many parts of the atmosphere, a
comet appears in one spot. The wind does not
mount up high, but comets are seen higher up than
the winds are permitted to go. Epigenes after
wards goes on to speak of the comets that, he says,
have a more definite resemblance to stars, traversing
an orbit and passing through the zodiacal signs.
He attributes their origin to the same causes as
produce those that he called lower comets, the only
difference being that the earth s exhalations in this
case contain many dry elements, and therefore seek



vii WIND AS CAUSE OF COMETS 279

the higher region, and are driven by the north wind
toward the more exalted portions of the heavens.
But, surely, if the north wind urged them, they
would always be borne toward the south, whither
this wind urges its course. And yet, as a fact, they 3
have had different movements, some to east, others
to west, all in a curved path, a direction which the
wind could not impart. Besides, if the impulse
which produced the comet carried up on high those
north winds from the earth, comets would not arise
when other winds blew ; yet they do arise.



VIII

LET us now refute this other explanation of i
Epigenes, for he employs two. He believes that
when all the moist and dry exhalations of the earth
unite, the mere discord of the different bodies turns
the air into whirlwind. Then the force of that wind
as it revolves sets fire by its rapid motion to all
that it embraces in itself, and raises it on high. The
gleam of the fire that is thus extracted remains as
long as there is sufficient nutriment ; when the fuel
fails, the fire subsides too. Now, one who talks 2
thus pays no attention to the nature of the
course of whirlwinds as compared with that of
comets. The career of the former is swift and
violent, more rapid than the winds themselves.
But a comet s movement is so gradual as to
render imperceptible the space traversed during
a day and a night. Besides, whirlwinds have an
erratic, disorderly, and, to use a word of Sallust s,
eddying, motion. Comets have a regular course,
which observes the appointed track. Surely none



280 PHYSICAL SCIENCE BK. vn

of us will believe that either the moon or the five
planets are carried by the wind or spun round
3 by the whirlwind. I trow not. And why ? Just
because they have not an irregular and unrestrained
motion. Let us apply the principle to comets.
They do not move in confusion or irregularity so as
to justify the belief that they are impelled by unruly
and fickle forces. Besides, even if those eddies
could enclose moist earthy elements, and had power
to raise them from the depths to the heights,
still they could not carry them up higher than the
moon. All their force is spent when they reach
the region of clouds. But as for the comets, we
see them sailing through the upper regions, mingling
with the very stars. It is, therefore, improbable
that a whirlwind could persist over such a long
distance, for the greater it is, the more rapidly is it
spent.

IX

1 LET Epigenes, therefore, make his choice of the
two alternatives : if the force is small, it cannot
reach so high ; if it is great and violent, it will the
more quickly break up. But further, according to
the opinion of people like Epigenes, these lower
comets do not mount higher because they have
too much earthiness in them. Their weight keeps
them in the neighbourhood of earth. And yet
these other comets, which are higher and last
longer, must have a more abundant material. For
they could not last so long were their supplies not

2 replenished from a larger stock. I said a moment
ago that the whirlwind s eddy could not long endure,
nor could it mount higher than the moon, or as far



ix INADEQ UACY OF EXPLANA TION 2 8 1

as the place of stars. Of course, the whirlwind is
caused by the mutual struggle of several winds, and
the contest cannot be kept up for any long time.
When the wandering uncertain air assumes a
rotatory form, in the last instance the force of all
the winds yields to the single strongest one. No 3
hurricane lasts long. The more strength squalls
have, the shorter their duration. When winds
reach their maximum, they quickly abate all their
violence. By that headlong speed they must needs
hasten to their own destruction. So no one has
ever seen a whirlwind last a whole day, or even an
hour. Its velocity is astonishing, its brevity no less
astonishing. Moreover, on the earth and near it, its 4
rotation is swifter and more violent ; the higher it is,
the less condensed and compact is it, and that is the
reason of its more rapid dissipation. Add the fact,
too, that even if it reached the highest region where
the stars path lies, it would most certainly be broken
up by the motion which causes the universe to
revolve. For what can compare in rapidity with
the revolution of the world ? Thereby the strength
of all the winds combined in one would be shattered,
aye, and the strong solid chain that binds the earth,
not to say a wisp of whirling air.



AGAIN, a fire carried along by a whirlwind cannot i
remain on high unless the whirlwind also remain.
But then what is so inconceivable as any prolonged
duration in a whirlwind ? Above all, the whirlwind
motion is neutralised by the opposite motion of
the heavens. That region on high to which it



282 PHYSICAL SCIENCE BK. vn

is alleged to mount has an eddying motion of its
own, which carries onward the sky,

And drags the lofty stars, and turns them in rapid whirl.

And even though one grant some duration to
whirlwinds, which is quite contrary to the fact, yet
what is to be said of the comets that have con-

2 tinued in sight for six months ? Then, as hinted
above, there must be two motions in the same spot
one that constant motion of the heaven, accom
plishing its task without intermission, the other a
strange new motion conveyed by the whirlwind.
The one must inevitably obstruct the other. And
yet that motion we see of the moon in her orbit,
and of the other heavenly bodies that pass above the
moon, is irrevocable. It nowhere falters or stops,
nor does it convey to us the slightest suggestion

3 of an obstacle being ever placed in its way. It is
utterly beyond belief that a whirlwind, the most
violent and unruly species of storm, should reach
the very centre of the ranks of the stars, and should
find a sphere for its boisterous activity in that
ordered peace of heaven. Supposing that the
revolution of a whirlwind kindles fire, which is
shot up to the heights, furnishing apparent ground
for the belief that what we see is a trail of fire ; yet
surely the shape of the fire ought to be something

4 like that which produces it. Now a whirlwind is
round in appearance ; it remains in the same track,
and revolves after the fashion of a rotating pillar.
The fire, therefore, that is enclosed ought to re
semble it in shape. But in reality it is a trail of
scattered fire, and resembles anything rather than
fire gathered into a ball.



xi DIFFERENT KINDS OF COMETS 283



XI

LET us now say good-bye to Epigenes, and proceed i
to examine the opinions of other writers. But
before beginning to set them forth, I must first, by
way of preface, remark that comets are not observed
only in one part of the sky, nor merely in the
zodiac, but in the east as well as in the west, more
frequently, however, toward the north. Nor is 2
their shape uniform. The Greeks, indeed, dis
tinguished three classes of them : those from which
the flame hangs down, after the fashion of a beard ;
those that shoot out what looks like hair round them
on all sides ; and those which have a scattered kind
of fire, which, however, stretches toward an apex. 1
But all the classes have a common characteristic,
and are rightly called comets (i.e. long-haired). As
the different shapes present themselves only at long
intervals, it is difficult to compare them with one
another. Even at the time of their appearance 3
spectators are not agreed as to their shape. Ac
cording as one s eyesight is keener or duller, one
asserts that the comet is brighter or redder, and
that its hair is compressed toward the interior of the
star, or spread out toward its sides. But whether
or not there are any differences in comets, they
must all be produced by the same method. The 4
one fact about which there ought to be agreement
is, that a star of strange unwonted appearance is
beheld which drags along with it scattered fire.
Some of the ancients are convinced of the truth of
this explanation : When one of the planets has
come into conjunction with another, the light of the

1 I.e. are cone-shaped.



284 PHYSICAL SCIENCE BK. vn

two blends in one, producing the appearance of a
more elongated star. This happens not merely
when star touches star, but even when one ap
proaches another. The space between the two
is in that case lit up by both, and seems aflame,
producing the trail of fire.



XII

1 OUR first answer to this theory is that the number
of moving stars (planets) is fixed. It is quite usual
for them and comets to appear at the same time ;
whence it is manifest that the comet is not due
to the conjunction of planets, but is a distinctive in
dependent star. Besides, it is a matter of frequent
occurrence for a star to come under the orbit of
a more elevated star. Saturn, for example, is
sometimes above Jupiter ; Mars looks down in

2 a straight line on Venus or Mercury. But yet
no comet is formed from this movement whereby
the one planet approaches the other. Were it
otherwise, there would be a comet every year, for
every year there are planets in the same constella
tion. Again, if the approach of star to star pro
duced a comet, the latter would cease to be in a
moment. The transit of stars takes place with
the utmost rapidity, thence all eclipse of heavenly
bodies is of brief duration ; by the same motion
they are as swiftly separated as they were brought

3 together. The sun and the moon, as we see, part
company within a brief space after the eclipse has
begun. How much swifter must be the separation
of stars, which are so much smaller ? Yet comets
last for six months at a time, which would not



xii CONJUNCTION OF PLANETS AS CAUSE 285

happen if they sprang from the union of two stars.
The stars cannot stick to one another for any long
time, and the law of their swift motion must ever
drive them asunder. Besides, those stars appear to 4
us to be close to one another, but in reality are
separated by immense distances. How, then, could
the one star transmit fire to the other so that the
two should seem in union, when they are thus
parted by an immense tract? The light of the
two stars, it is replied, mixes, furnishing the ap
pearance of one. I suppose this means that the
phenomenon is much the same as when a cloud
takes a ruddy colouring from the rays of the sun
striking on it, or as when there is the golden
glow of evening or morning, or as when the bow
is painted in its varied hues, but only in sunshine.

Well, my first criticism is that all the instances 5
mentioned are the result of great force. It is the
sun that lights them up. The stars do not possess
anything like the same power. My second remark
is that none of the phenomena arises except below
the moon in the vicinity of the earth. The upper
regions are pure and spotless, always retaining their
own colour. I remark further, that if anything of the
kind did occur, it would not last but would speedily
disappear, as halos which surround the sun or
moon fade in a very brief space of time. Even 6
the rainbow does not long remain. If there was
anything of the kind supposed, to unite the space
between the two stars, it would disappear with
equal rapidity. In any case it would not remain
as long as comets are in the habit of doing. The
planets have their orbits within the zodiac, they
lie near this circle ; but comets are seen in all parts
of the sky. Their time of appearance is no more



286 PHYSICAL SCIENCE BK. vn

certain than the limits of the space which they may
not exceed.



XIII

1 IN reply to arguments like mine it is urged by
Artemidorus that the five planets are not the only
stars with erratic courses, but merely the only ones
of the class that have been observed. But in
numerable others revolve in secret, unknown to us
either by reason of the faintness of their light, or
the situation of their orbit being such that they
become visible only when they reach its extremities.

2 It is thus, he says, that certain new stars enter our
field of vision, mingling their light with the fixed
stars, but displaying a brightness greater than is
usual in stars. This is the least serious of his lies :
his account of the universe is from end to end a
shameless tissue of lies. For instance, if we are to
believe him, the upper regions of heaven are
perfectly solid a lofty thick vault, as hard as the
roof of a house, formed by the accumulation of
masses of atoms. The surface immediately above
it is of fire so compact that it cannot be broken up

3 or altered. Nevertheless, it has certain ventilators,
and, as it were, windows through which portions of
the fire stream from the outer part of the universe,
but not so large as to cause commotion in the inner ;
and again the fires pass from the world back into
the outer spaces. These extraordinary appearances,
therefore, Artemidorus supposes, have streamed in
from that mass of matter which lies outside the
world. To set about disproving such a theory is
nothing short of beating the air for the sake of
exercising the muscles !



xiv A SOLID FIRMAMENT! 287



XIV

STILL, I will descend to the task. Let the man i
who has placed such a solid roof on the world tell
me what reason there is for believing his statement
that the heavens have such a thickness. What was
it that took all these solid bodies up there and kept
them there ? Then, a firmament of such thickness
must necessarily be of immense weight too. How
is it that heavy bodies remain aloft ? How is it
that the huge mass does not come down and smash
itself by its own weight? It is, I imagine, a 2
physical impossibility that such a vast weight as
Artemidorus has brought to the support of the
heavens should hang suspended, or be supported by
a slight foundation. Nor can it be alleged that
there are stays l of some kind outside by which it
is prevented from falling. Nor again can there be
any support in the centre 2 to receive and prop up
the threatening mass. And again, no one will
venture to assert that the universe is being con
stantly carried down through the immensities of
space, falling all the time, though it is not evident
that it falls, because its headlong course is to all
eternity, having no final obstacle with which to
collide. This is indeed a statement people have 3
made about the earth, when they could discover no
explanation for a mass standing poised in air. It is
borne down, say they, for ever ; but it is not evident
that it falls because the space into which it falls is
endless.

1 The word is usually applied to a flexible fastening, hawser, cable, or the
like.

2 Or, between the earth and it.



288 PHYSICAL SCIENCE BK. vn

Well, what argument 1 then justifies the assertion
that it is not merely the five planets that move,
but that there are many such in many quarters
of the universe ? Or if there is no probable
proof of this, one may rejoin : What is there to
prevent one from saying either that all the stars
4 move or that none of them does ? Besides, your
argument is in no way helped by that crowd of stars
which you assume to be everywhere roaming about !
For the more there are of them, the oftener will
they meet with others ; whereas comets are rare,
and for that reason marvellous. And will not
every age give evidence against you by noting and
recording for the use of posterity the emergence of
such stars ?



XV

1 AFTER the death of Demetrius, king of Syria,
whose kingdom was divided by his sons Demetrius
and Antiochus, a little before the Achaean War, a
comet blazed forth not inferior to the sun in size.
Its orb was at first fiery red, and emitted a bright
light sufficient to dispel the darkness of night. By
and by its size was gradually reduced and its
brightness waned. Finally it went completely out.
How many stars, suppose you, would require to

2 combine to make up such a huge mass ? You
might collect in one a thousand of them without
ever matching the size of the sun. In the reign of
Attalus a comet appeared, moderately small in size
to begin with. By and by it mounted up and spread
out and moved as far as the equator, equalling in

1 The argument is resumed from the beginning of XIII. after the
digression about the "firmament."



xv CONJUNCTION THEOR Y ERRONEO US 289

the extent of its immense length the whole quarter
of the sky which we call the Milky Way. How
many planets must have combined to occupy with
an unbroken line of fire such a long tract of the
sky?



XVI

I HAVE refuted the argument ; I must now discredit
its authors. It requires no great effort to strip
Ephorus of his authority ; he is a mere chronicler.
Some of his class seek to recommend their narrative
by incredible stories, and by their marvels try to
interest the reader, who would probably soon find
some other occupation if he were called on to wade
through their tedious narrative of ordinary events.
Some, again, are too credulous, some too careless,
some are deluded, some delighted, by falsehood.
The former do not shun it, the latter go in quest of
it. The whole clan of them have this in common ;
they fancy their work cannot merit approval, and
become popular unless they freely interlard it with
lies. Ephorus is not a person of any scrupulous
honour; he is often duped, often he tries to dupe. For
example, he asserts that the great comet which, by
its rising, sank Helice and Buris, which was carefully
watched by the eyes of the whole world since it
drew issues of great moment in its train, split up
into two stars ; but nobody besides him has re
corded it. Who, I wonder, could observe the
moment at which the comet broke up and was
resolved into two parts ? And if there is any one
who saw it split up into two, how is it that no one
saw it first formed out of the two ? And why did
Ephorus not add the names of the two stars into

u



2 9 o PHYSICAL SCIENCE BK. vn

which it was broken up, since they must have been
some of the five planets ?



XVII

1 APOLLONIUS of Myndus differs in his view from
Epigenes. He asserts that a comet is not one star
made up of many planets, but that many comets are
planetary. A comet, he goes on, is not an illusion
nor a trail of fire produced on the borders of two stars,
but is a distinctive heavenly body, just as the sun or
the moon is. Its shape is not limited to the round,
but is somewhat extended and produced lengthwise.

2 On the other hand its orbit is not visible. It cuts
( = intersects) the upper part of the universe, but
only emerges when at length it reaches the lowest
portion of its course. There is no reason to suppose
that the same comet reappears ; for instance that
the one seen in the reign of Claudius was the same
as the one we saw in the reign of Augustus ; or that
the recent one which appeared during the reign of
Nero Caesar which has redeemed comets from
their bad character was similar to the one which
burst out after the death of the late Emperor Julius
Caesar, about sunset on the day of the games to

3 Venus Genetrix. Comets are as varied as they
are numerous. They are unequal in size, unlike in
colour. Some are ruddy without any light ; others
are bright with a pure clear light ; others are flame-
coloured, but the flame is not a pure thin flame, but
is enveloped in a mass of smoky fire. Some are
blood-stained and threatening, bringing prognosti
cation of bloodshed to follow in their train. They
wax and wane like other planets. They are brighter



xvii COMET IS NOT PLANET 291

when they come down toward us, and show larger
from a nearer point, smaller when they depart
from us, and dimmer when they retire to a greater
distance.



XVIII

THE reply is ready to this last statement, that the i
same thing does not happen in comets as in the
other stars. Some comets attain their maximum on
the very first day of their appearance. But, according
to the argument, they ought to increase the nearer
they approach. As it is, their first aspect remains
until they begin to fade. Besides, what has
been said in reply to former authorities applies here
too : If the comet had an erratic orbit, and were a
true planet, it would move within the limits of the
zodiac, within which all the planets confine their
orbits. Again, a star is never seen through another 2
star. Our sight cannot pierce through the centre
of a planet so as to view through it what lies be
yond. But through a comet the further regions are
discerned as through a cloud. Whence it is evident
that it is no planet but an insubstantial, irregular
fire.

XIX

THE following is the opinion of our Stoic sage Zeno. i
He is convinced that the stars act in concert, and
unite their rays with one another a partnership in
light which creates the image of a more elongated star.
Therefore some persons suppose that comets have
no real existence, and that it is only the appearance
of them that is reproduced through the reflection



292 PHYSICAL SCIENCE BK. vn

of neighbouring stars or the union of stars that
2 stick together. Some, again, say that comets are
true stars, but with orbits of their own, and that after
certain periods they come out into the view of man
kind. Some allow their existence but refuse them
the title of stars, because they glide out of sight
without long duration, and within a brief space are
scattered to the winds.



XX

1 MOST of our Stoic brethren entertain another view,
which they do not regard as inconsistent with fact.
Let me explain it. We observe many species of
fire engendered on high, now the heavens ablaze,
now

Long glistening trains of flame behind,

now huge torches of fire being hurried along.
The lightning itself, whose velocity is so marvel
lous that it at once blinds, and at the same instant
restores, the sight, is fire arising from the friction
of air that suffers more violent internal pressure

2 than usual. That is why it does not remain long,
but glides off once it issues from the cloud, forth
with perishing. But other fiery appearances remain
for a considerable time, and do not break up until all
the fuel on which they fed has been used up. Here
belong the strange sights recorded by Posidonius

pillars and shields all ablaze, and other flames
of marvellous strangeness. They would attract no
attention if they ran their course after customary
laws ; but now the sight of them sends all men agape.

3 They bring down sudden fire from the heights of
heaven, sometimes producing a flash which is gone



xx STOIC VIEW 293



in a moment, sometimes compressing the air, which
is forced into a glow ; it is a miracle all the
same. Yes, and is not sometimes a gulf opened
in the ether, which seems to retire on all sides, with
a great glare of light in the hollow centre ? You
are ready to cry out. What is this ?

... I see the very centre of heaven open,
And the stars wandering in the sky. . . .

These stars sometimes do not wait for night to
show their light, but burst out in the full light
of day. The reason, however, for the stars show- 4
ing at a time not their own is different from
that alleged ; it is well known that they are there
all the time, though hidden. Many comets, too,
we cannot see because they are obscured by the
sun s rays. Posidonius, in fact, tells us that during
an eclipse of the sun a comet once appeared which
the sun s proximity had hitherto concealed. Often,
when the sun has just set, straggling fires *
are seen close to him. No doubt the nucleus of
the comet is bathed in sunlight, and therefore
cannot be discerned ; but the tail escapes the effect
of the sun s rays.

XXI

OUR Stoic friends, therefore, are satisfied that, like i
trumpet meteors and beams, and other portents
of the sky, comets are formed by dense air. They
appear in greatest number toward the north, be
cause there is most of the sluggish air there. Why,
then, you naturally ask, does the comet not remain
stationary, but advance in the sky from day to
day ? Let me explain. The comet, according to

1 I.e. the tail of a comet.



294 PHYSICAL SCIENCE BK. VH

this account, pursues its fuel just as fires do. Al
though its tendency is to rise to the upper regions,
still, if material fail it, it retrogrades and sinks. In
the air, too, it does not pursue a direct path to right

2 or left. It has no particular route assigned to
it ; wherever the supply of its fuel leads it, thither it
crawls ; it does not advance in its orbit as a star,
but feeds as a fire. Why, then, does it appear for a
long period, and why is it not quickly extinguished ?
For the recent one which we saw during this joyous
reign of Nero displayed itself to view for six months,
revolving in the opposite direction to the former
one in Claudius time. That one rising from the
north up toward the zenith made for the east,
always growing dimmer. This one began in the
same quarter, but making toward the west, turned
finally toward the south, where it withdrew from

3 view. No doubt the former found moister elements,
more suitable for its fire, and pursued them ; the latter
in turn chose a richer and more substantial district.
So they descend toward the direction in which they
are invited by their material, and not by a definite
path, which in the two we have seen was different,
since the one moved off toward the right and the
other toward the left. Now all stars l have their
orbit in one direction, namely, contrary to the motion
of the universe. The latter moves from east to
west, the stars go from west to east. For this
reason they have a double motion, one, their own
proper motion ; the other, which carries them round
along with the heavens.

1 Planets may be specially referred to ; the Latin word is the generic one,
stella.



xxii REFUTATION OF STOICS 295



XXII

I DO not agree with my school here, for I cannot i
think a comet is a sudden fire, but I rank it among
Nature s permanent creations. First of all, every
thing that the atmosphere creates is short-lived ;
such things arise in an element that is fugitive and
changeable. How can anything continue the same
for long in the air, which itself never remains the
same? It is always in a state of flux, and its quiet
is short-lived. It changes within a brief moment
to another condition from that in which it had been.
It is now rainy, now clear, now alternates from 2
one to the other. The clouds, so intimately con
nected with it, into which it collects and from which
it is released again, now gather, now disperse, but
never remain at rest. Fire cannot possibly abide
securely in a volatile body, nor can it keep its place
so persistently as does a fire that Nature has fixed
never to be dislodged. Further, if the fire stuck
close to its fuel, it would always sink. For the air 3
is the thicker, the nearer it is to the earth. But a
comet is never depressed to the lowest strata of the
atmosphere, nor does it ever approach the ground.
Besides, fire either goes in the direction its nature
prompts, that is, upwards, or else in the direction
in which it is drawn by the material on which it
has fastened, and on which it feeds.



XXIII

IN none of the ordinary fires in the sky is the route
curved ; it is distinctive of a star (planet) that it



296 PHYSICAL SCIENCE BK. vn

describes a curve in its orbit. Whether other
comets had this circular orbit I cannot say. The
two in our own age at any rate had. Again, every
thing kindled by a temporary cause quickly gives
out. Thus torches gleam only while they flit across
the sky ; thus lightning has strength for just one
stroke ; thus so-called shooting and falling stars fly

2 past, cutting through the air. No fires have any con
siderable duration unless their strength is inherent. I
mean the divine fires which the universe maintains
eternally, because they are its parts and works.
These, I say, are always active ; they have an orbit
the even tenor of which they preserve, and they are
uniform. They would on alternate days be larger
or smaller if the fire was merely casual, the sudden
outcome of some accidental cause. Such a fire
would be greater or less according as it was fed
more abundantly or more scantily. I said a
moment ago that no fire could be lasting which

3 arose from some defect in the atmosphere. I have
now to add further, that it can by no means be fixed
and steady. Both torch and lightning and shooting
star, and any other kind of fire forced out of the air
by pressure, are in flight ; none of them is visible
save in the course of its fall. But a comet has its
own settled position. For that reason it is not
expelled in haste, but steadily traverses its course ;
it is not snuffed out, but takes its departure. If it
were a wandering star (i.e. planet), says some one, it
would be in the zodiac. Who, say I, ever thinks
of placing a single bound to the stars ? or of cooping

4 up the divine into narrow space ? These very
stars, which you suppose to be the only ones that
move, have, as every one knows, orbits differing
one from another. Why, then, should there not be



xxm UNIQUENESS OF COMETS 297

some stars that have a separate distinctive orbit far
removed from them ? What reason is there why
there should not be passages into the heavens at
some part of them ? 1 But if you are convinced
that every star (planet) cannot but touch the zodiac,
then I say the comet might have such a wide orbit
that at some point it may coincide with the zodiac.
This is not necessary, but it is possible.



XXIV

CONSIDER whether it is not more in keeping with
the size of the universe that it be supposed to be
divided into many routes, and do not keep this one
beaten track while every other portion is a waste.
Do you suppose that in this great and fair creation,
among the countless stars that adorn the night with
varied beauty, never suffering the atmosphere to
become empty and sluggish, there are only five
stars that are allowed to move freely, while all the
rest stand still, a fixed, immovable crowd ? Should
any one here ask me : Why, then, has their course
not been observed like that of the five planets ? my
answer to him shall be : There are many things whose
existence we allow, but whose character we are still
in ignorance of. We shall all admit that we have a
mind, by whose behest we are urged forward and
called back ; but what that mind is which directs
and rules us, no one can explain any more than he
can tell where it resides. One will say that it is
breath ; another, a kind of harmony ; another, a
divine force and part of God ; another, subtlest air ;

1 The meaning seems to be, there may be passages inlets and outlets
by which occasional visitants like comets may temporarily enter the heavens
as we know them, and subsequently pass out of them. The text is doubtful.



298 PHYSICAL SCIENCE BK. vn

another, disembodied power. Some will even be
found to call it blood, or heat. So far is the mind
from being clear on all other subjects that it is
still in search of itself.

XXV

1 WHY should we be surprised, then, that comets, so
rare a sight in the universe, are not embraced under
definite laws, or that their beginning and end are
not known, seeing that their return is at long
intervals ? It is not yet fifteen hundred years since
Greece

Counted the number of the stars and named them every one.

2 And there are many nations at the present hour
who merely know the face of the sky and do not
yet understand why the moon is obscured in an
eclipse. It is but recently indeed that science
brought home to ourselves certain knowledge on
the subject. The day will yet come when the
progress of research through long ages will reveal
to sight the mysteries of nature that are now
concealed. A single lifetime, though it were
wholly devoted to the study of the sky, does not
suffice for the investigation of problems of such
complexity. And then we never make a fair
division of the few brief years of life as between
study and vice. It must, therefore, require long

3 successive ages to unfold all. The day will yet
come when posterity will be amazed that we
remained ignorant of things that will to them seem
so plain. The five planets are constantly thrusting
themselves on our notice ; they meet us in all the
different quarters of the sky with a positive challenge
to our curiosity. Yet it is but lately we have begun



xxv SLO W PROGRESS OF KNO WLEDGE 299

to understand their motions, to realise what their
morning and evening settings mean, what their
turnings when they move straight toward us, why
they are driven back from us. We have learned
but a few years ago whether Jupiter would rise or
set, or whether he would retrograde the term that
has been applied to his retirement from us. People 4
have been found bold enough to say to us : You are
mistaken in thinking that any star ever stops orwheels
in its course. The heavenly bodies may not stand
or turn away. All advance ; once the signal is
given they start on their race. Their career will
end only with their existence. This eternal creation
has motions that suffer no recall. Should they once
be arrested, they will encounter obstacles in front
which are meantime held in place by the ordered,
regular march of the universe.



XXVI

WHAT then is the reason, you may ask, for the
apparent retrogression of some heavenly bodies ?
The appearance of slowness in their motion is
caused by their encountering the sun, as well as by
the character of their paths and the position of their
orbits, which are at certain periods calculated to
deceive the eye. Ships in the same way moving
under full sail seem withal to be stationary. Men
will some day be able to demonstrate in what
regions comets have their paths, why their course is
so far removed from the other stars, what is their
size and constitution. Let us be satisfied with what
we have discovered, and leave a little truth for our
descendants to find out.



300 PHYSICAL SCIENCE BK. vn

We cannot, Apollonius says, see through the
stars what is beyond, but sight passes easily
2 through the comets. Well, in the first place, if
that is the case, it is not so in the part of the
body which consists of dense solid fire, but only
where the dispersed glow extends as it breaks up
into the appearance of hair. One can see through
the gaps in the fire and not through the fire
itself. Stars again, it is said, are all round, comets
extended ; whence it is plain that they are not true
stars. But who, pray, will allow that comets are
long ? Their tendency like that of other stars is to
a globe shape, only the light from them is prolonged.
The sun shoots out his rays far and wide, but has
himself a shape different from that of the light that
streams from him. So in comets, the body is
rounded, but the glow from them presents the
appearance of being longer than that of the other
stars.

XXVII

1 WHY is this so, you ask. Do you tell me first why
the light the moon receives is wholly unlike the
sun although she receives it from the sun. Why is
it now ruddy, now pale ? why is her colour ashen or
black when she is cut off from the sun s view ? Or
tell me why all the stars have aspects to some extent
dissimilar to one another and all as different as
possible from the sun. It is no hindrance to their
being true stars that they are not all alike ; so there
is nothing to prevent comets from being permanent
through all time, sharing the same destiny as the
other stars, even though they have not an appearance

2 like theirs. Besides, is not the universe, if you will



xxvn NATURES RIDDLES 301

only examine it carefully, made up of contrarieties ?
Why is it that the sun should be always blazing
hot in Leo, scorching the ground with his fierce
glow, while in Aquarius he brings winter s chain
and closes the rivers with ice ? The one con
stellation is subject to the same law as the other,
though its characteristics and influence are so
different. Aries again rises in a moment, Libra
lifts its scales very slowly ; yet the one sign is of
the same nature as the other, though that one
mounts in a brief space, this comes forth very
deliberately. Do you not see, too, how contrary
the elements are to one another ? They are heavy 3
and light, cold and hot, moist and dry. The whole
concord of the universe is a harmony of discords.
You say a comet is not a star, because its form does
not correspond to the type, but is unlike other stars.
You can see, no doubt, how very like that star that
returns to its place after thirty years is to this which
revisits its haunt within the year ! Nature does
not turn out her work according to a single pattern ;
she prides herself upon her power of variation. She 4
has made some things larger, some swifter than
others ; some stronger, some more limited in power ;
some she has separated from the crowd, that their
splendid isolation might render their progress con
spicuous ; some she has consigned to a place in
the common herd. He has little conception of
nature s power who thinks that she may not do
exceptionally what she does not do repeatedly.
She does not often display comets ; she has assigned
them a different place, different periods from the
other stars, and motions unlike theirs. She wished
to enhance the greatness of her work by these
strange visitants whose form is too beautiful to be



302 PHYSICAL SCIENCE BK. vn



thought accidental, whether you consider their vast-
ness or their brightness that surpasses in size and
brilliance all other stars. Their appearance has, in
truth, an exceptional distinction ; they are not cribbed
and cabined within narrow bonds, but let loose to
roam freely, to range over the region of many stars.



XXVIII

1 ACCORDING to Aristotle, comets give indications of
storm and disturbances that bring wind and rain.
Well, then, are you of opinion it is not a star because
it foretells what is coming ? True the comet is not
a sign of storm in the same way as it is a sign of
coming rain when

The oil splutters, and rotten fungus covers the wick ;

or in the same way as it is a forecast of a raging

sea if

the sea

Coots 1 sport on land ; her haunts in the marshes
Are deserted by the heron, and she soars above the heights of
cloud :

2 but in the same way as the equinox is a sign of the turn
of the year toward cold or heat, or as the predictions
of the Chaldaean soothsayers who tell what sorrow or
joy is determined at birth by the natal star, are
indications of coming events. To convince you of
the truth of this, I must warn you that the rising of a
comet does not convey a threat of wind and rain in
the immediate future, as Aristotle says, but casts
suspicion over the whole year. Hence it is plain
that the comet has not derived prognostications
from its immediate surroundings to reveal for the

1 Perhaps cormorants : the identity of the bird is difficult to determine.



xxvni PROGNOSTICATIONS FROM COMETS 303

immediate future, but that it has them stored up and
buried deep within by the laws of the universe. The
comet which appeared in the consulship of Paterculus
and Vopiscus fulfilled the anticipations of this kind
entertained by Aristotle, and for that matter by
Theophrastus ; for there were everywhere severe 3
and prolonged storms, while in Achaia and Macedonia
cities were overturned by earthquakes. The slow
ness of the comets motion, Aristotle says, is a proof
that they are rather heavy, containing much earthy
matter. So are their orbits too, for they are usually
confined to the neighbourhood of the poles.



XXIX

BOTH statements are false. Let me take them in i
their order. Well, it is asserted, is it, that all
bodies are heavy that move more slowly ? What !
is the planet Saturn, which accomplishes its circuit
most slowly of all the planets, heavy? It has, in
fact, a proof of lightness in being higher than all
the rest. But, you say, it takes a wider sweep, and
does not go more slowly than the others, but only
a longer distance. Let me suggest that I can
make the same statement of the comets ; even if
their i course is more sluggish, they have farther
to go. But it is a falsehood to assert that they 2
move more slowly. For this last comet traversed
within six months half the span of heaven ; the
previous one withdrew from sight in a shorter
period. But again, it is urged, on account of their
weight, they are borne down lower. Well, in the first
place, a comet is not borne down, but round. In
the second, this recent one began its motion in the



304 PHYSICAL SCIENCE BK. vii

north, and passing by way of the west, reached the
southern quarters, and was elevating its orbit when
3 it faded from sight. That other one, in Claudius
reign, also first appeared in the north, and con
tinued without intermission to rise straight up to
a higher elevation until it disappeared. Such are
the matters relating to comets which have had
weight with others and with myself. Whether they
are true or not, those who attain knowledge of the
truth must decide. We are permitted only to con
jecture and grope in the dark, with no assurance of
discovery, and yet not without hope.



XXX

1 ARISTOTLE has finely said that we should never be
more reverent than when we are treating of the
gods. We enter a temple with all due gravity,
we lower our eyes, draw up our toga, and assume
every token of modesty when we approach the
sacrifice. How much more is all this due when
we discuss the heavenly bodies, the stars, the
nature of the gods, lest in ignorance we make
any assertion regarding them that is hasty, or dis-

2 respectful ; or lest we wittingly lie. Let us not
be surprised that what is buried so deeply should
be unearthed so slowly. Panaetius and others,
who will have it that a comet is not an ordinary
star but the mere counterfeit of a star, have bestowed
careful treatment on the question whether all seasons
of the year are equally fitted to produce comets,
and whether all quarters of the sky are equally
suitable for their creation. They have inquired,
too, whether they can be formed in all regions



xxx REVERENCE AND HUMILITY OF SCIENCE 305

through which they can pass, and have discussed
other points of a like kind. But all these questions
are foreclosed by my statement that they are not
accidental fires, but inwoven in the texture of the
universe, directed by it in secret, but not often
revealed. And how many bodies besides revolve 3
in secret, never dawning upon human eyes? Nor
is it for man that God has made all things. 1 How
small a portion of His mighty work is entrusted
to us ? But He who directs them all, who estab
lished and laid the foundations of all this world,
who has clothed Himself with creation, and is the
greater and better part of His work, He is hidden
from our eyes, He can be perceived only by
thought.

XXXI

MANY things, moreover, akin to highest deity or i
holding power near it, are still obscure. Or, perhaps,
one may be still more surprised to find that they
at once fill and elude our sight. Either their
subtlety is too great for human vision to grasp,
or such exalted majesty conceals itself in the holier
sanctuary, and rules its kingdom, which is itself,
without permitting access to any power except the
spirit. What that is, without which nothing is, we
cannot know : and when God, the greatest part of the
universe, is an unknown God, we are surprised, are we,
that there are some specks of fire we do not fully
understand ? How many animals we have come to 2
know for the first time in our own days ! Many,
too, that are unknown to us, the people of a coming
day will know. Many discoveries are reserved for

1 Another reading runs : Nor has God revealed all things to man.

X



3 o6 PHYSICAL SCIENCE BK. vn

the ages still to be, when our memory shall have
perished. The world is a poor affair if it do not
contain matter for investigation for the whole world
in every age. Some of the sacred rites are not
revealed to worshippers all at once. Eleusis retains
some of its mysteries to show to votaries on their
second visit. Nature does not reveal all her secrets
at once. We imagine we are initiated in her
mysteries : we are, as yet, but hanging around her

3 outer courts. Those secrets of hers are not opened
to all indiscriminately. They are withdrawn and
shut up in the inner shrine. Of one of them this age
will catch a glimpse, of another, the age that will
come after.

When, then, it may be asked, will all these
things come to our full knowledge ? Great schemes
mature slowly, especially if effort is relaxed. There
is one object we are bent on, heart and soul,
to be as wicked as possible and we have not

4 yet attained perfection. Vice is still making pro
gress. Luxury is constantly discovering some new
outlet for its madness, indecency some new form of
insult on itself. Dissolute effeminacy and corruption
are constantly discovering some more refined and
delicate means of self-destruction. We have not yet
wholly cast off our vigour. We are still doing our best
to extinguish any spark of virtue that is left. By the
smoothness and polish of our bodies we men have out
done the refinements of women ; we have adopted the
colours of harlots, that even an honest woman would

5 not put on. With delicate mincing step we check
our gait ; we do not walk, with measured pace we go.
We adorn our fingers with rings. A precious stone
sparkles on every joint. Day by day we devise
means of wronging and degrading our manhood,



xxix PHILOSOPHY UNFASHIONABLE 307

vexed that we cannot strip it off. One becomes a
eunuch, another assumes the scandalous part of a
gladiator, and, hired for death, arms for disgrace.
The very pauper selects a victim on whom to sate
his morbid lust.



XXXII

Do you wonder that wisdom has not yet attained i
her perfect work ? Why, vice has not wholly re
vealed itself. It is still in its infancy, and yet
on it we bestow all our efforts ; our eyes and our
hands are its slaves. Who attends the school of
wisdom now ? Who thinks it worth while to have
more than a bowing acquaintance with her ? Who
has regard for philosophy or any liberal pursuit,
except when a rainy day comes round to interrupt
the games, and it may be wasted without loss ? And
so the many sects of philosophers are all dying out 2
for lack of successors. The Academy, both old and
new, has left no disciple. Who is there to hand down
the precepts of Pyrrho ? That famous school of
Pythagoras, despised of the rabble, can find no master.
The new sect of the Sextii, which contained the
vigour of Rome, started with great enthusiasm, but
on the very threshold of its career is also dead.

But what anxious care we bestow that the name 3
of no actor may be lost ! The house of Pylades
and Bathyllus stands in a long line of successors.
For arts of that kind there are plenty of pupils and
plenty of teachers. The actor s platform resounds
in every private house in the whole city. On
it men and women alike practise the ballet step.
Husbands and wives vie in paying court to actors.
By and by, when the brow is rubbed smooth by



3 o8 PHYSICAL SCIENCE BK. vn

long wearing of the mask, the transition to the
4 brothel is easy and natural. Philosophy gets
never a thought. And so it comes to pass that,
far from advance being made toward the dis
covery of what the older generations left insuffi
ciently investigated, many of their discoveries are
being lost. But yet, on my soul of honour, if we
urged on this task with all our powers, if our youth
in sobriety braced themselves to it, if the elder
taught it and the younger learned it, even then
scarce should we reach the bottom of the well in
which truth lies. As it is, we search for her on
the surface, and with a slack hand.