BOOK VII

WHICH TREATS OF COMETS

I

No man is so utterly dull and obtuse, with head so bent on earth, 1

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, which paints with beauty the spacious 2

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 are the ordinary movements of the sun! He takes, so to speak, 3

as many steps as there are days, completing the year in his circuit.

From the summer solstice he turns back to the lessening days, from the

solstice he slopes his rays,[90] and gives more 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 moon, except when she is right opposite 4

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.

[90] 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.

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 whether to admire or to 5

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,[91] 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 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.

[91] The common reading, _aliis_ = others, seems an error for _illis_

= them.

II

In view of this inquiry it will be well to ask whether comets are 1

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 stars are pure fire and nothing else, remaining for 2

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 deserves our study, if we are to know where we 3

really stand, whether the abode we have obtained 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 reappearance at the

appointed day. Such a development of astronomy is recent, having been

lately introduced into Greece.

III

Democritus, the most acute of all the ancient philosophers, says he 1

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 worked out. Subsequently Conon, who was himself a 2

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

Apollonius of Myndus, the latter highly skilled in casting 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 the views of the 1

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 constellations next Mars, or crosses

to the neighbourhood 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 is thunder and lightning. If he has Mars in agreement, the 2

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 from one another 3

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 line of fire, which lasts

just so long as the mass of air remains, which carries within it the

supply of moist earthy matter.

V

This account of Epigenes is a tissue of falsehoods. To begin with the 1

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 rotates as on a pivot. And in addition to this, it 2

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. Callisthenes puts it on record

that a similar appearance of a trail of fire was observed before the

sea swallowed up Buris and Helice. Aristotle says it was not a “beam,” 3

but a comet; the characteristic dispersion of the fire was not seen

at first on account of its excessive brightness, but, in process 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 of comets. One kind 1

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 is capable of setting on fire 2

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 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 according to appointment. His opinion may

be briefly expressed by saying that he supposes comets to be formed 3

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 1

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 afterwards goes on to speak of the comets that, he 2

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 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 Epigenes, for he employs 1

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 thus pays no attention to the nature of the 2

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 of us will believe that either the moon or the

five planets are carried by the wind or spun round by the whirlwind.

I trow not. And why? Just because they have not an irregular and 3

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

Let Epigenes, therefore, make his choice of the two alternatives: 1

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 replenished

from a larger stock. I said a moment ago that the whirlwind’s eddy 2

could not long endure, nor could it mount higher than the moon, or as

far 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 hurricane lasts long. The more strength 3

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 rotation is swifter and more violent; the higher it 4

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.

X

Again, a fire carried along by a whirlwind cannot remain on high 1

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 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

continued in sight for six months? Then, as hinted above, there 2

must be two motions in the same spot--one that constant motion of

the heaven, accomplishing 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 of an obstacle being ever placed in its way.

It is utterly beyond belief that a whirlwind, the most violent and 3

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 like that which produces

it. Now a whirlwind is round in appearance; it remains in the same 4

track, and revolves after the fashion of a rotating pillar. The fire,

therefore, that is enclosed ought to resemble it in shape. But in

reality it is a trail of scattered fire, and resembles anything rather

than fire gathered into a ball.

XI

Let us now say good-bye to Epigenes, and proceed to examine the 1

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, distinguished 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.[92] 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 spectators are not agreed as to their shape. According 3

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 one fact about which there ought to be agreement is, that 4

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 two blends in one, producing the

appearance of a more elongated star. This happens not merely when star

touches star, but even when one approaches another. The space between

the two is in that case lit up by both, and seems aflame, producing the

trail of fire.

[92] _I.e._ are cone-shaped.

XII

Our first answer to this theory is that the number of moving stars 1

(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 independent 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 a straight line on Venus or Mercury.

But yet no comet is formed from this movement whereby the one planet 2

approaches the other. Were it otherwise, there would be a comet every

year, for every year there are planets in the same constellation.

Again, if the approach of star to star produced 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 together. The sun and the moon, as we see, part company 3

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 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 us to be close to one 4

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 appearance 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 mentioned are the 5

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 the rainbow 6

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 certain than the limits of the

space which they may not exceed.

XIII

In reply to arguments like mine it is urged by Artemidorus that the 1

five planets are not the only stars with erratic courses, but merely

the only ones of the class that have been observed. But innumerable

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. It is

thus, he says, that certain new stars enter our field of vision, 2

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 or altered. Nevertheless, it has certain ventilators, and, as 3

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

Still, I will descend to the task. Let the man who has placed such a 1

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[93] of some kind outside by which it is prevented from falling.

Nor again can there be any support in the centre[94] to receive and

prop up the threatening mass. And again, no one will venture to

assert that the universe is being constantly 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 made about the earth, when they could discover no 3

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.

[93] The word is usually applied to a flexible fastening, hawser,

cable, or the like.

[94] Or, between the earth and it.

Well, what argument[95] 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 move or that none of them does? Besides, your argument 4

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?

[95] The argument is resumed from the beginning of XIII. after the

digression about the “firmament.”

XV

After the death of Demetrius, king of Syria, whose kingdom was 1

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 combine to make up such a

huge mass? You might collect in one a thousand of them without ever 2

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 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 1

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 2

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 recorded it. Who, I wonder, could observe

the moment at which the comet broke up and was resolved into two 3

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 which it was broken up, since they

must have been some of the five planets?

XVII

Apollonius of Myndus differs in his view from Epigenes. He asserts 1

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. On the other hand its orbit is not visible. It cuts 2

(‍=‍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

Venus Genetrix. Comets are as varied as they are numerous. They are 3

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

prognostication of bloodshed to follow in their train. They wax and

wane like other planets. They are brighter 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 same thing does 1

_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 star. 2

Our sight cannot pierce through the centre of a planet so as to view

through it what lies beyond. 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. He is convinced 1

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 of neighbouring stars or the union of stars that stick 2

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 mankind. 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

Most of our Stoic brethren entertain another view, which they do not 1

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 marvellous 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 than usual. That

is why it does not remain long, but glides off once it issues from 2

the cloud, forthwith 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. They bring down sudden fire from the heights of heaven, 3

sometimes producing a flash which is gone 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

showing at a time not their own is different from that alleged; it 4

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[96] 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.

[96] _I.e._ the tail of a comet.

XXI

Our Stoic friends, therefore, are satisfied that, like trumpet meteors 1

and beams, and other portents of the sky, comets are formed by dense

air. They appear in greatest number toward the north, because 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 this account,

pursues its fuel just as fires do. Although 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 or

left. It has no particular route assigned to it; wherever the supply 2

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 view. No doubt the former found moister

elements, more suitable for its fire, and pursued them; the latter 3

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[97] 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.

[97] Planets may be specially referred to; the Latin word is the

generic one, _stella_.

XXII

I do not agree with my school here, for I cannot think a comet is a 1

sudden fire, but I rank it among Nature’s permanent creations. First of

all, everything 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 one to 2

the other. The clouds, so intimately connected 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 is the thicker, 3

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 1

is distinctive of a star (planet) that it 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, everything 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 past, cutting

through the air. No fires have any considerable duration unless 2

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 arose from some defect in the atmosphere. I

have now to add further, that it can by no means be fixed and steady. 3

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 up the divine into narrow space? These very 4

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 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?[98] 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.

[98] 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.

XXIV

Consider whether it is not more in keeping with the size of the 1

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 2

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; 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

Why should we be surprised, then, that comets, so rare a sight in the 1

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.

And there are many nations at the present hour who merely know the 2

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 successive ages to unfold

all. The day will yet come when posterity will be amazed that we 3

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 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 have been found bold enough 4

to say to us: You are mistaken in thinking that any star ever stops or

wheels 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 1

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.

We cannot, Apollonius says, see through the stars what is beyond, but

sight passes easily through the comets. Well, in the first place, if 2

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

Why is this so, you ask. Do you tell me first why the light the 1

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 like

theirs. Besides, is not the universe, if you will only examine it 2

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 constellation 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 and 3

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 has made some 4

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 conspicuous; 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 thought accidental, whether you consider their vastness 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

According to Aristotle, comets give indications of storm and disturb- 1

ances 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[99] sport on land; her haunts in the marshes

Are deserted by the heron, and she soars above the heights of cloud:

[99] Perhaps cormorants: the identity of the bird is difficult to

determine.

but in the same way as the equinox is a sign of the turn of the year 2

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 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 and prolonged storms, 3

while in Achaia and Macedonia cities were overturned by earthquakes.

The slowness 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 their order. Well, it 1

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 course is more sluggish, they have farther to go.

But it is a falsehood to assert that they move more slowly. For this 2

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 north, and passing by way of

the west, reached the southern quarters, and was elevating its orbit

when it faded from sight. That other one, in Claudius’ reign, also 3

first appeared in the north, and continued 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 conjecture and grope in the

dark, with no assurance of discovery, and yet not without hope.

XXX

Aristotle has finely said that we should never be more reverent 1

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 disrespectful; or lest we wittingly lie. Let us not 2

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 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 in secret, 3

never dawning upon human eyes? Nor is it for man that God has made all

things.[100] How small a portion of His mighty work is entrusted to us?

But He who directs them all, who established 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.

[100] Another reading runs: Nor has God revealed all things to man.

XXXI

Many things, moreover, akin to highest deity or holding power near 1

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 know for the first time in our own 2

days! Many, too, that are unknown to us, the people of a coming day

will know. Many discoveries are reserved for 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 outer courts. Those secrets of hers are not opened 3

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 yet attained perfection. Vice

is still making progress. Luxury is constantly discovering some new 4

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 outdone the refinements of women; we have adopted

the colours of harlots, that even an honest woman would not put on.

With delicate mincing step we check our gait; we do not walk, with 5

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, 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 her perfect work? Why, 1

vice has not wholly revealed 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 for lack of successors. 2

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 of no actor may be 3

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 long wearing of the mask, the

transition to the brothel is easy and natural. Philosophy gets never 4

a thought. And so it comes to pass that, far from advance being made

toward the discovery of what the older generations left insufficiently

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.

NOTES ON SENECA’S “QUAESTIONES NATURALES”

By Sir ARCHIBALD GEIKIE, K.C.B., Pres.R.S.

The treatise of which the present volume is a translation possesses

a twofold interest. In the first place, it is probably the last

literary work of a man who filled a large space in the Roman world of

his day. After a varied career as philosopher, barrister, politician,

statesman, courtier, and man of letters, he at last incurred the

implacable enmity of Nero, to whom he had been tutor. Having in his

youth paid some attention to physical inquiries, he had then been

led to prepare and publish a book on earthquakes. But in subsequent

years the absorbing cares of State probably left him little leisure to

continue these studies, for which, however, he had retained his taste.

Hence, when in his last days he sought in retirement to devote himself

to philosophical pursuits, he naturally turned to some of the physical

problems that had interested him in earlier life. The earthquake

which on 5th February A.D. 63 had done much damage to the towns of

Campania, revived his youthful enthusiasm for the investigation of

such phenomena, and may possibly have suggested to him the preparation

of another volume dealing with this and other scientific matter. We

know at least from the book itself that he wrote a part, if not the

whole, of it after that date (221, 230),[101] and that he took pains

to collect information about the catastrophe. As he was in the habit

of sojourning on the shores of the Bay of Naples, he probably visited

the scene of destruction himself for the purpose of his book. We learn

from Tacitus that it was immediately after his return from Campania

to his villa near Rome, bringing with him, we may suppose, his nearly

completed manuscript, that Seneca received the Emperor’s order to

commit suicide.

[101] The numbers within parentheses throughout these Notes refer to

the pages of the Translation.

In the second place, Seneca’s work on _Natural Questions_ stands out as

one of the few treatises on physical science which have come down to us

from antiquity. It is interesting alike for the quotations it contains

from the works of previous authors, some of which have not survived,

and for the criticisms and opinions which he himself expresses on

the various subjects of which he treats. It can hardly, however, be

regarded as an original contribution to science. Its author’s life had

been spent in other and widely different pursuits, which led him far

away from scientific inquiry. But as a summary of the general state

of knowledge in his day, made by a man of strong intellect, who had

been trained in the legal and philosophical schools of the time, and

had read widely and reflected much on these matters, the book may be

taken to afford a fair presentation of the manner in which a number

of questions in astronomy, meteorology, and physical geography were

regarded by thoughtful minds in the first century of our era.

In judging of the intrinsic merit of such a work as the present, the

modern reader finds a difficulty in realising from the broad platform

of natural knowledge which, after the labours of the intervening

centuries, has now been laid, how exceedingly narrow was the circle

of ascertained fact available to the student two thousand years ago.

The spirit of scientific observation and experiment had not then been

developed, yet the familiar phenomena of everyday life pressed, as

they still do, for explanation. Man’s knowledge of nature was then too

limited to furnish a basis for distinguishing what was fact from what

was mere guesswork. In the infancy of our race, as in the childhood

of the individual, the tendency of the human mind is to perceive

resemblances rather than differences. Analogies are readily observed

and, in default of knowledge of the facts involved, are mistaken for

identical sequences of cause and effect. Throughout the interpretations

of natural phenomena given by the philosophers of antiquity, it is

remarkable to what a large extent the meaning of one appearance is

explained by comparing it with another to which in reality it may bear

no resemblance. Seneca’s volume abounds in examples of this use of

analogy.

The authority of great names exercised a wonderful fascination on the

minds of the early investigators of nature. Generation after generation

of writers were led to accept with little or no modification the dicta

of eminent philosophers who had preceded them. An observer might

sometimes recognise the erroneousness of the opinion of a predecessor,

and yet lack the means of detecting the falsity of his own, which

nevertheless he propounded with full assurance of its truth. In such

circumstances criticism had no secure foundation, while credulity,

rampant in the world outside, could hardly fail to show itself in

philosophic circles. Even the most cautious and truth-seeking inquirer

might easily and almost inevitably be led to accept statements which

did not seem to him unreasonable, and which no previous experience of

his own or others warranted him to disbelieve or even to suspect.

It behoves us, therefore, to be on our guard lest, from our much higher

standard of knowledge, we may be tempted to look with amused contempt

on the puerile conceptions of nature to be met with in the writings of

the ancients--the grave assertion of absurdities as actual facts, the

inept analogies, the confident explanations which are no explanations

at all, and the complete absence of any attempt to test by examination

or experiment the validity of statements which with but little trouble

could have been disproved.

These evidences of the exceedingly imperfect knowledge of his time

are fully illustrated in Seneca’s chapters. He quotes some two dozen

of previous writers who had dealt with the same or cognate subjects.

It is needless to say that they were Greeks, no place having yet

been found in Latin literature for treatises on Science. The author

most frequently cited by him is Aristotle, whose _Meteorologica_

he had evidently studied with care. He gives frequent quotations

from that work, but even where he does not specifically quote, his

views generally accord with those of the great philosopher and

naturalist.[102] Almost the only quotations from the works of his own

countrymen are verses from some of the poets, especially from Virgil

and Ovid. It is remarkable that he makes only one quotation from

Lucretius, although he would have found in that poet’s noble work many

passages more apposite to his subject than those which he has taken

from the _Aeneid_, the _Georgics_, and the _Metamorphoses_. We may

suppose that these works were favourites with him, and that he knew

much of them by heart, but that he was less familiar with the _De Rerum

Natura_.

[102] Seneca’s indebtedness to Aristotle is emphatically expressed

by Barthélemy Saint-Hilaire in the Dissertation prefixed to his

translation of the _Meteorologica_ (_Météorologie d’Aristote_, 1863,

pp. lxix-lxx).

It is manifest from the present volume that its author, like Lucretius

before him, had a lofty conception of the dignity and moral influence

of the study of nature. This pursuit seemed to him to raise us above

the sordid things of life and to withdraw the mind from the body--a

dissociation so eminently beneficial to our higher aspirations. He

believed that in the study of the hidden phenomena of the universe a

mental alacrity is developed which will be found to be not without

practical utility in the conduct of affairs that lie nearer the surface

(113).

With this clear recognition of the importance of his theme he resolved

in his old age to enter upon a task which other less worthy pursuits

had hindered him from pursuing. He would now attempt to survey the

universe, unravel its secrets, and give the results of his studies to

the world (109). It was not, however, his aim to compose a systematic

treatise on Natural Philosophy, but rather to take up some special

subjects and deal with them in the light of what had already been

written upon them, and of what his own reflections suggested. His

undertaking assumed the form of a series of epistolary essays addressed

to his friend Lucilius Junior, procurator of Sicily. The literary shape

thus selected allowed the use of an unconstrained, almost colloquial,

style which would not have been suitable to a more ambitious work.

Had Seneca designed to prepare a formal or methodical treatise, he

would doubtless have planned it to include the three sections which he

regarded as comprising every inquiry that can arise as to the nature

and constitution of the Universe (_Universum_)--celestial, atmospheric,

and terrestrial (_Caelestia, Sublimia, Terrena_, 51). The world

(_Mundus_) in his view comprehends all things that come or can come

within our cognisance (54). Instead of entering upon a full discussion

of any one of his three sections, he selected from them a few topics

which had probably more particularly engaged his attention. Most of

these belong to the second or atmospheric division of his scheme of

arrangement, to which he devotes six of his seven books, the remaining

one being given to the discussion of some celestial phenomena. Certain

subjects which we should naturally range in the terrestrial series,

such as the source and flow of rivers and the nature and origin of

earthquakes, he explicitly includes among his atmospheric phenomena

(51).

It appears to be probable that Seneca had neither finished nor revised

his manuscript at the time of his death. Parts of the work are

obviously incomplete, though some of these gaps may be due to defects

of transcription or to the subsequent loss of parts of the text. The

obscurities of language, which are not infrequent, may likewise have

partly arisen from lack of the author’s revision of his original copy.

His discussion of the problem of the rise of the Nile suddenly breaks

off in such an abrupt manner as to suggest the loss of a portion of the

original volume. One of the most important omissions is the absence of

any account of the phenomena of volcanoes. The author does indeed refer

in several places to this subject, but with Aetna before him, of which

so many Greek and Latin poets had sung, and which had so often been

referred to in the writings of the philosophers, he could hardly have

meant to offer no commentary on so notable a feature in the geography

and history of his own country. We know indeed that he was keenly

interested in this mountain, and that he wrote to Lucilius to ascend

the volcano and send him particulars about it. In the letter conveying

this request he alludes to some of the Roman poets who had sung of its

wonders, and urges that a description of Aetna should form part of a

poem on which his correspondent appears to have been then engaged.[103]

Another important subject in physical geography finds no place in

Seneca’s volume--the Sea. Of the outer ocean it was not to be expected

that he could have had much to say, but we can hardly suppose that he

would have considered his essay complete without some discussion of the

various phenomena presented by the Mediterranean Sea.

[103] Seneca, _Epist._ lxxix.

A century before Seneca’s prime, the immortal _De Rerum Natura_ of

Lucretius had appeared at Rome, wherein the origin and constitution

of the world were sung with the intense earnestness, brilliant

imagination, and resounding cadence of a great poet and with the grasp

and penetration of a great philosopher. In this splendid work some of

the problems discussed by Seneca were considered, and explanations

were given of them with the usual undoubting confidence of olden

time. In literary quality the two writers stand far apart, yet it is

not uninteresting to compare their respective views of nature. The

vivid and often majestic diction of the one is not more diverse from

the somewhat familiar and conversational tone of the other than are

their respective creeds. Lucretius was a convinced and enthusiastic

Epicurean, and in accordance with the teachings of his master denied

the existence of any divine co-operation in the plan and government of

the Universe,

nequaquam nobis divinitus esse paratam

naturam rerum,[104]

[104] _De Rerum Natura_, v. 198.

although no writer either of ancient or modern time has had a more

overpowering sense of the beauty, majesty, and order of this world. It

was his earnest purpose to show men how, by a contemplation of the face

and ordered scheme of nature, they could free themselves from the bond

of religious superstition and the fear of death.[105]

[105]

rursus in antiquas referuntur religiones

et dominos acres adsciscunt, omnia posse

quos miseri credunt, ignari quid queat esse,

quid nequeat, finita potestas denique cuique

quanam sit ratione atque alte terminus haerens.--_Op. cit._ v. 86.

hunc igitur terrorem animi tenebrasque necessest

non radii solis neque lucida tela diei

discutiant, sed naturae species ratioque.--i. 146.

Seneca, on the other hand, held the Stoic belief in an all-wise and

omnipotent Creator. In an eloquent exordium to his volume, and in a

peroration near its end, he affirms his conviction that this Divine

Being is all in all, at once within and without his works; He has

clothed himself with creation, but is hidden from our eyes and can

be perceived only by thought (3, 7, 305). Our philosopher could not

conceive of anything more beautiful, more orderly, and more consistent

everywhere in plan than the world around us. That such a world should

have resulted from the tumult of chaos, by the mere chance collocation

of atoms, appeared to him the madness of vulgar error. Yet it was

only too true, though it might be thought hardly credible, that even

philosophers had been tainted with this pernicious doctrine. Hence it

would be in the author’s judgment a profitable task to inquire into the

truth concerning these matters. To explore this world, he remarks, is

far more than enough for a single lifetime. Whether what we may be led

to believe regarding it shall be true must be decided by those who may

attain the knowledge of the truth; we can but examine and conjecture,

with no certain assurance of discovery, yet not without hope (304).

It behoves us to be ever watchful against forming conclusions rashly,

disrespectfully, or ignorantly, and of being knowingly untrue. In this

quest after knowledge, while much may be found out which will be of

practical usefulness, we are encouraged to advance, not by any hope

of gain, but by the wonder with which the inquiry fills the soul. To

obtain a knowledge of Nature is the highest reward to which the mind of

man can aspire (230, 304). Seneca’s practical conclusion was thus much

the same as that of Lucretius. He does not, however, attempt in this

volume to enforce it with the solemn earnestness shown by the poet,

though he loses no opportunity of inveighing against the follies and

vices of his time. In discussing natural phenomena his first desire is

to explain them, and in so doing to animadvert on the explanations of

previous writers, with perhaps a not unnatural wish to show his own

ability as a critic and expositor.

It was in due accordance with the principles of his school, as well as

with his own natural temperament, that Seneca should continually be led

to draw ethical lessons from the physical phenomena which he discussed.

The interpolation of some of these reflections may occasionally seem

to a modern reader rather irrelevant and far-fetched, but there can be

no question as to the spirit of reverence with which he approached his

subject. Like other philosophers who had preceded him, he maintained

this spirit, while at the same time he had discarded the crowded and

confused polytheism of the prevalent mythology. But he here keeps

this antagonism in due restraint, only occasionally expressing his

dissent from the popular creed. He would not admit that even the old

philosophers could have been so foolish as to credit the gods with some

of the acts which had been popularly attributed to them. He refused to

believe that the guardian and ruler of the Universe hurled thunderbolts

with his own hand. Still less could he suppose that the gods had

lighter bolts with which they amused themselves in play. His expression

(fulminibus lusoriis, 91) recalls the bitter irony of Lucretius and the

sarcasm of his question whether, when the gods aim at lonely places or

at the sea, they are only at practice to strengthen their arms.[106]

But Seneca held with Lucretius that in the contemplation of nature we

obtain the courage and elevation of mind which fit us for the trials

of life and the coming of death (113).

[106] an tum bracchia consuescunt firmantque lacertos?--vi. 397.

In the treatment of scientific problems Seneca displays the same

unhesitating assurance of the truth of his opinions, which was

characteristic of the philosophers of antiquity. These writers had

hardly a glimmering conception of nature’s infinite complexity, of

the extreme diversity and intricacy of natural processes, of the

unbroken and endlessly ramifying relations of cause and effect, of

the long and patient investigation by which alone these relations

could be unravelled, and of the caution and diffidence with which

conclusions regarding them should at least for a time be formulated.

Seneca frequently passes caustic criticisms on the views expressed by

his predecessors. He styles the philosophers, as a body, “a credulous

folk.” Some of them he even goes so far as to accuse of perpetrating

deliberate falsehoods (276, 286, 289). Nor does he hesitate to banter

his brethren of the Stoic School, whose “absurdities,” as he calls

them, he cannot refrain from quoting.

Yet when his own opinions are examined in the light of the present

day, they are found to be in many cases no nearer the truth than those

which he rejected with contempt. It is, indeed, sometimes difficult to

realise the mental position of a man who could adopt and propound them.

In many cases he accounts for a phenomenon by the analogy of another

to which it has no real affinity, as where he explains halos by the

circular undulations produced on a surface of water into which a stone

is thrown (13). He sometimes suggests an experiment to prove the truth

of his assertion, but if he had made the experiment he would have found

how completely it failed to support him, as, for instance, when he

states that a large pond of water reflects only one image of the sun,

but that, if it is divided into several smaller ponds by the insertion

of partitions, it will show as many images as there are divisions

(18). Striking also and numerous are the examples of his credulous

acceptance of statements which, had it occurred to him to test them

by actual examination, he could easily have found to be erroneous.

He affirms, for instance, more than once, that while lightning melts

metals, it freezes wine, and he gravely alleges that when the wine is

thawed and imbibed, it either kills or drives mad those who partake

of it (79, 97). He asserts that the waters of certain rivers have the

power of dyeing whole flocks of sheep, black fleeces being changed

into white, and white into black (137), that some waters are so dense

that even the heaviest objects will not sink in them (138); that the

heat of the sun in the Nile valley is so great as to melt silver and

the joints of statues (173). When he proceeds to explain the reason of

such abnormalities he expresses no hesitation, but delivers his opinion

with the assurance of a professor who has obtained the experimental

demonstration in his laboratory.

It is remarkable that although some progress had been made in

astronomy, especially by Greek philosophers, before the beginning

of the Christian era, the conclusions arrived at by these observers

regarding the relations of the earth to the other heavenly bodies met

with but little acceptance for many centuries, even among reflecting

minds. Lucretius, for example, still believed the earth to be the

centre of the Universe to which all the heavier materials had

converged, while the fire-laden ether escaped to the outer boundaries

of space, sun, moon, and stars occupying an intermediate place. He did

not think that the sun can be much larger than it looks to be to our

senses, nor was he quite sure whether it is the same sun which, passing

under the earth, reappears in the morning, or if at the close of each

day the sun is extinguished and a new collection of fires makes a

fresh sun in the morning. He was quite aware of the different views of

Chaldaean sages and astronomers, but in such questions he could see no

reason why one theory should be better than another.[107]

[107] _De Rer. Nat._ v. 564, 650, 680, 727.

Seneca, however, had, on the whole, a more advanced appreciation of

the relations of the earth to the heavenly bodies. He believed the sun

to be larger than our globe, and that a thousand stars might be put

together without equalling his mass (284, 288). He thought the heavens

to be so vast as to afford space for the swiftest of the planets to

rush along with uninterrupted speed during full thirty years (7). He

showed his enlightened outlook upon astronomical possibilities when he

surmised that comets may have orbits that carry them far beyond the

Zodiac, and when he conjectured that other planets than those then

known remained to be discovered (296–299). And yet, sharing these more

enlarged conceptions, he clung with curious pertinacity to some of the

old childish faith which was natural in the infancy of mankind. He

knew that some philosophers held that it is the earth which revolves

and not the heavens, and though he does not deliberately reject this

opinion, it is evident that he still held that the heavens circle

round the earth.[108] Again and again he expresses his conviction that

the force which sustains the energy of the sun and the stars consists

of the exhalations that arise from the surface of the earth. These

exhalations, he says, are the pasturage of the heavenly bodies, the

breath of the world. It would be impossible, he asserts, for the earth

to furnish so ample a store of nourishment to bodies larger than itself

unless it were full of breath which is passing off from every part of

its surface both by day and night. To the obvious objection that the

supply of this energy would soon become exhausted, he has the reply

that this exhaustion would certainly take place were it not that the

elements are in a condition of continual transformation, issuing in

one form, passing into each other, and returning to their original

positions, thence to begin their cycle anew (55, 198, 244–5). In this

universal transmutation water passes into air, air into water; air

likewise is changed into fire, fire into air, while earth is formed

from water, and water from earth (120).

[108] See _postea_, Notes on Book VII.

In his general conception of the universe, Seneca, as a Stoic

philosopher, recognised a principle of evolution. He believed that the

world embraces in its constitution everything that it is destined to

experience from its beginning to its end. As a human embryo contains

the germ of the future man, so at the first creation of the universe,

sun and moon, the changes of the stars, and the birth of living things

were all embraced. And there were likewise included the forces whereby

the earth is affected, and which will ultimately lead to the final

destruction of the globe (151).[109]

[109] Lucretius, too, had his views on evolution, which are well

expressed in four lines of verse:

mutat enim mundi naturam totius aetas,

ex alioque alius status excipere omnia debet,

nec manet ulla sui similis res: omnia migrant,

omnia commutat natura et vertere cogit.

--_De Rer. Nat._ v. 828.

With regard to the earth itself, whether it is to be regarded as a

soul or as an organised body, Seneca announced his conviction that it

has been constructed much after the plan of our human bodies. As in

these bodies, veins and arteries are provided for the reception of

blood and breath, so in the earth there are passages, some for the

transport of water, others for the flow of air (126). He was sure,

also, that everything on the surface of the earth has its counterpart

beneath--caves, mountains, lakes, and rivers.

BOOK I

In this part of his Essay the author has grouped together a variety of

phenomena, some of which are meteorological (in the modern sense of

that word), and belong therefore to his class of Sublimia, while others

are astronomical, and would be properly placed among his Caelestia.

They all have reference to light in some form, and doubtless for that

reason were considered as a series. Seneca, largely swayed by the

opinions expressed in Aristotle’s _Meteorologica_, agrees with that

philosopher in the belief that the earth gives forth various kinds of

exhalations, among which some contain the seeds of fire. He thought

that high up in the air, among dry and hot elements, these fires may

be kindled by the sun’s rays, and further, that when the atmosphere

becomes violently disturbed its friction may give rise to fires (9, 10,

39).

With these ideas, which he held as established truths, it is easy

to understand that he should have regarded as extremely foolish the

notion that any of the lights which move rapidly across the sky are of

celestial origin. Had such been their source, he felt sure that by this

time there would have been none left in the firmament; yet although

no night passes when some of them may not be seen, each star in the

sky is found to maintain its place and its size. Hence he confidently

concluded that the meteors, which are seen at night, and sometimes even

by day, have their birth far below the stars, and are soon extinguished

in their course because they have no solid and abiding resting-place.

Single aerolites and even showers of stones had been recorded in Roman

literature as having fallen from heaven, but it had not yet occurred to

any observer to connect them with the shooting stars which gleam across

the nocturnal sky, and are now recognised to be due to meteorites of

different sizes, entering our atmosphere with planetary velocity, there

breaking up with varying luminosity, and remaining visible for shorter

or longer intervals of time.

The author appears to have regarded as akin to these meteors the

star-like balls of light, which in stormy weather are sometimes seen

on the masts of vessels at sea, and which before his time had been

observed on the points of the spears of an army in the field. This

luminous appearance, regarded by the Romans as a sign of the friendly

presence of Castor and Pollux, is entirely atmospheric, and has no

connection with shooting stars. It is now known as St. Elmo’s Fire, and

has been shown to be a gentle continuous electric discharge from the

earth towards a cloud.

Seneca next describes in some detail a series of optical appearances

connected with the sun and moon. Until the laws of the reflection and

refraction of light had been discovered, it was obviously impossible

to account for these phenomena. There is, therefore, much interest in

following the lines of thought by which the old philosophers attempted

to explain them. Seneca clearly perceived that the halos and coronae

seen round the sun and moon in certain states of the atmosphere do

not belong to these luminaries, but to our own air, and may furnish

indications of coming weather. He remarks shrewdly enough that

appearances akin to those seen in the sky may sometimes be observed in

the thick moist air of a bathroom. But when he confidently proceeds to

explain the meteorological phenomena he betakes himself to analogy, as

he is so fond of doing. He remarks that when a stone is thrown into a

pond a succession of circles is produced on the surface of the water,

which continually widen from the point of impact until they lessen and

disappear. In like manner he believes that when the light of the sun or

moon strikes the cloudy air it produces a similar effect, for as every

kind of light is round in shape, the air is thus driven into a circular

form. His love of analogy generally, as in this instance, leads him far

away from the truth, and prevents him from seeing the palpable flaws in

his reasoning. But the apparent similarity of appearances, which are in

reality entirely dissimilar, contents him with his explanations.

His discussion of the rainbow (16–33) is one of the most detailed

and vivacious in the whole volume. It takes the form of a sustained

argument, in which the author cites various authorities, and replies

to objections brought by a supposed opponent to his thesis, which is

that the rainbow is unquestionably an image of the sun received in a

very moist cloud which has the shape of a round concave mirror (20,

27). He quotes with apparent approbation the opinion that in a shower

of rain each falling drop is a mirror reflecting an image of the sun,

and that when an observer stands directly between the sun and the

shower he sees the reflections of the countless drops blended into one

continuous semicircle. But as the discussion proceeds the writer denies

that the cloud consists of separate rain-drops, and he maintains

that even if it did they would not unite to give one unbroken image.

In proof of his contention he urges the fallacious assertion that if

a number of mirrors are joined together and a man is placed before

them, each gives its own reflection, and thus a single man becomes

multiplied into a crowd. If he had ever tried the experiment or had

visited the shop of a mender of mirrors, he would have seen that the

separate pieces, if strictly arranged on the same plane, reflect a

single image. His imaginary antagonist asks for an explanation of the

rainbow-like colours displayed by the spray from a burst water-pipe,

or the splash from an oar, which are, of course, cases strictly

parallel to the falling shower of rain (24). The resemblance is at

once granted, but is explained away on the ground that the drops fall

so quickly that they cannot form reflections of the sun, and that to

produce such reflections the medium must be at rest. The objector once

more strikes in with a reference to the rainbow colours to be seen in

a glass rod which is placed obliquely in the path of the sun’s rays

(30). These prismatic tints, as has long been known, are due to the

same decomposition of white light, as in the rainbow. But Seneca claims

the illustration as furnishing additional arguments in his favour. He

maintains that no colour is really produced in the rod, but only a

false appearance of colour, his idea being apparently that unless the

colour is inherent in an object apart from direct sunlight, it is only

apparent and not real. The glass, he says, tries to reproduce the sun’s

image, but fails because of its unsymmetrical form, the reflections

being crowded together and confused into the appearance of a single

band of colour. In regard to the falling drops of rain in a shower he

contends that they receive the colour but not the image of the sun, and

he is led away by the false analogy of the varying tints of a peacock’s

neck as the bird tosses its head (25). At one part of the discussion

he affirms that the colours of the rainbow come partly from the sun

and partly from the moist cloud (21). Further on, however, he agrees

that they proceed from the sun, but are only apparent, for if another

cloud comes across the face of the luminary they at once vanish (29).

The greater diameter of the rainbow compared with that of the sun as

seen by us he accounts for by the analogy of a concave mirror, which

greatly enlarges the objects reflected from it. At the conclusion of

the discussion he repeats his belief that the rainbow and the corona

or halo have no definite material inherent in them, but are like a

mirror which reveals only a deception, the mere phantoms and empty

imitations of real bodies, which certainly do not exist in the mirror,

and therefore cannot come out of it (41).

In Chapters XVI. and XVII. the author indulges in one of his favourite

moralising episodes, suggested by the topics he has been discussing

in the previous pages. He takes the existence of reflecting surfaces

as his text, and from the calm surface of still water passes on to

artificial mirrors, contrasting the manners and morals of early

mankind, who had only pools and lakes in which to see their faces, with

the luxury and vice of later ages, when the use of metals led to the

invention of metallic mirrors. In this retrospect, however, he places

the discovery of the use of iron before that of the other metals. The

priority of bronze and the reason for it are accurately stated by

Lucretius:

et prior aeris erat quam ferri cognitus usus,

quo facilis magis est natura et copia maior.[110]

[110] _De Rer. Nat._ v. 1287.

BOOK II

In this division of his work the author discusses various aspects of

the atmosphere and offers an explanation of the phenomena which he

describes. He distinguishes between the very bright ether on high,

and the moist, denser atmosphere which underlies it, but thinks that

they must pass insensibly into each other (66). The atmosphere he

regards as a continuous non-composite body, capable of great range in

tension, and forming the vehicle through which the exhalations from

the earth pass outwards to the sky. It does not everywhere possess

the same qualities. In its lower parts next the earth it is dense and

misty, owing to the terrestrial exhalations, and is there warmed by the

earth’s breath, by the reflection of the sun’s rays from the ground,

and from the fires, artificial and subterranean, as well as from the

warmth communicated by living animals and plants, for life cannot exist

without heat. The highest portions of the atmosphere are exceedingly

dry, hot, and attenuated, owing to their nearness to the eternal fires

and the heat of the heavenly bodies. The middle parts, on the contrary,

are intermediate in character, but colder than what lies above and

below them (60, 61). It is the lower portions that are subject to the

greatest changes, for they receive the earthly elements which involve

such constant turmoil. The instability of the air arises also in part

from the motions of the earth and from those of the sun, moon, and

stars, to which cold, rain, and other atmospheric disturbances are due

(56, 61).

Seneca, in passing on to discuss the nature and origin of thunder and

lightning, divides the phenomena into three kinds--lightning-flashes,

thunderbolts, and thunderings (62). After citing and commenting on the

opinions of various philosophers he proceeds to give his own views

regarding these appearances. The lightning flash (_fulguratio_) he

looks upon as fire widely spread out, the thunderbolt (_fulmen_) as

fire condensed and hurled with violence (66). The difference between

the two is in force rather than character; a flash is a bolt without

strength enough to reach the earth, while a thunderbolt is lightning

in its most intense form (69). With regard to the origin of the fire

he points out that fire may be artificially produced in two ways:

either by percussion, as when stones are struck; or by friction, as

when two bits of wood are rubbed against each other. He thinks that

probably in both of these ways clouds may emit fire, and that in the

violence of storms a source of energy is supplied whereby the warm or

smoky exhalations from the earth may be kindled and fall with a fierce

glow to the earth (70, 101). These exhalations contain dry and moist

bodies, to which heavier elements may be added. A combination of such

materials will form a thicker and more solid cloud than one of pure

air, and such a cloud may burst with a loud report (78). There can be

no peal of thunder unless the hollow clouds are broken up with great

violence (76). The characteristic path of the thunderbolt is determined

by the oblique current of air in which, while the natural tendency of

the fire is upward, the violence of its discharge presses it downwards

and compels it to take up a zig-zag course. The peculiar ozone odour

noticed during thunderstorms, and long popularly known as the smell of

sulphur, is alluded to by Seneca (69, 97) and by Lucretius.[111]

[111] Similar views on thunder and lightning are expressed in the _De

Rerum Natura_:

semina quod nubes ipsas permulta necessust

ignis habere.--vi. 206.

post ubi conminuit vis eius et impetus acer,

tum perterricrepo sonitu dat scissa fragorem.--_Ibid._ 128.

... notaeque gravis halantis sulpuris auras.--_Ibid._ 221.

The discussion of these subjects leads on to a disquisition on the

portents that may be drawn from different kinds of thunder and various

forms of lightning. Seneca infers from the effects produced by it that

lightning possesses an inherent divine power. Among these effects he

enumerates some in which he seems to have thoroughly believed, such,

for instance, as the smashing of a wine jar already quoted, and the

freezing of the wine for the space of three days thereafter. He is

thus disposed to attach credit to the opinion that future events are

foretold by both lightning and thunder. Yet he cannot change his Stoic

faith that fate, that is, the necessity for the happening of all things

and all actions, can be set aside by no force, can be altered by no

portents, nor averted by any prayer or sacrifice. Though he admits that

vows and supplications may be useful to the worshippers, he knows that

even these also are included in the decrees of fate.

These reflections lead the philosopher to a characteristic peroration

on the moral lessons to be derived from the subjects he has been

discussing. From the dangers incident to thunderstorms he passes to

the enforcement of the Stoic doctrine that death must be despised, and

everything which leads to death will then cease to have any terror.

BOOK III

The subjects comprised in this section of the treatise have reference

chiefly to the springs and rivers which appear on the surface of the

earth or flow underneath it. The Book begins with a preface, which

may have been originally designed to stand at the beginning of the

volume. It bears internal evidence of having probably been written at

the time of the author’s resolve to take up the discussion of physical

problems, as it speaks of old age pressing upon him and leaving him but

a short while to cover the immense field which he wished to survey. The

years lost among vain pursuits must be repaired by diligence in the

task now undertaken; night must be added to day, and every social or

business care which can possibly be set aside must be abandoned. The

contemplation of the work before him then leads the philosopher into

his moralising mood, wherein he inquires what should be the principal

object of human life, concluding with the reflection that the best

thing a man can set before himself, among the ups and downs of this

world, is courage to accept them calmly and to be ready to meet death

boldly whenever summoned. To the acquisition of such a courage a

contemplation of nature will greatly conduce.

Seneca begins his discussion of the various forms of water by grouping

them into two chief classes, standing in collected sheets, as in lakes,

or running in channels, as rivers above ground and springs underneath.

After a brief enumeration of various qualities of water, he inquires

whence the vast volume of water comes that is carried down by rivers

to the sea, and how it happens that neither is the earth sensible of

this daily loss, nor does the ocean show any perceptible gain. He

merely notices the opinion which some philosophers had expressed that

the sea does not get larger because it restores to the earth as much

water as it receives, allowing its own saline water to sink through

endless subterranean winding passages wherein it is purged of its

saltness and rises on the land as pure fresh water.[112] Another view,

that most of the water supplied by rain eventually finds its way into

the rivers, is approximately that at which modern research has arrived,

but it meets with our philosopher’s strong opposition. His first

objection is derived from his own observation. He tells us that, as a

diligent digger among his vines, he can confidently affirm that even

the heaviest rain does not penetrate to a depth of more than ten feet

from the surface. What is not absorbed by the upper crust of the ground

runs at once into river channels, and thence into the sea. He next

asks how rain, which immediately flows off the surface of naked rocks,

can possibly be the source of the springs and rivers that issue from

bare crags, or how springs that appear on the very summit of mountains

can be due to rain. Though he could not but be aware of the close

connection everywhere observable between evaporation, rainfall, and the

volume of springs and rivers, he does not seem to have reflected on

its meaning--how in seasons of drought the surface waters fail first,

how by degrees the springs begin to lessen and even to cease, how the

rivers dwindle until in many cases their beds become almost or quite

dry, and yet how, when welcome rains set in, the springs and rivers

gradually resume the bulk they had before the dry weather impoverished

them. He had made no study of the way in which rain percolates through

the soil, subsoil, and rocks underneath, though there are places, such

as his vineyard may have been, where, from some impervious material,

only a feeble or inappreciable flow of moisture descends beyond a few

feet from the surface. Nor was he aware of the innumerable lines of

joint by which the most solid rocks are traversed, and which serve

as passages for the descent and ascent of water. Had he climbed many

mountains, he would have failed to find a spring on the summit of any

one of them, unless there had been a sufficient area of higher ground

at hand to serve for the supply of the water.

[112] This is the view expressed by Lucretius:

... ut in mare de terris venit umor aquai,

in terras itidem manare ex aequore salso;

percolatur enim virus, retroque remanat

materies umoris et ad caput amnibus omnis

confluit, inde super terras redit agmine dulci.

--_De Rer. Nat._ vi. 633.

The origin of underground water is regarded by Seneca as due to

three causes. The earth itself contains moisture which it forces out

at the surface; it includes also air which in the darkness of the

subterranean wintry cold is condensed into moisture; by the principle

of interchangeability, whereby one element passes into another, the

earth in its interior resolves itself into moisture. If it be urged

that the rivers are too vast to draw their supplies from these sources,

the ready answer comes that the internal reservoir is quite spacious

enough for the purpose, and that it might as well be matter of surprise

that, with all the winds that constantly blow, the supply of air does

not fail, or that a single wave of the sea should be left to follow

so many breakers. If the questioner, still unsatisfied, should demand

to know how water is produced, he is met with the query how air is

produced on earth. There are in nature four elements, and he is not

entitled to ask where one of them comes from. Each is a fourth part of

nature, and it is obvious that what has an element as its source cannot

fail. Hence the philosopher in pronouncing water to be an element has

given it enough, and more than enough, of strength. In short, rain may

give rise to a torrent, but not a river flowing steadily between its

banks. Heavy rains will swell such a river, but cannot produce it.

Having, as he believed, cleared the ground in this way, Seneca proceeds

to consider the distribution of water within the earth. He opines that

as in our body, so in the earth, there are channels by which both air

and liquids flow. He states his conviction that the earth contains not

only veins of water, but also large streams, and in a later part of the

volume he speaks of both underground rivers, huge lakes, and a hidden

sea from which rivers at the surface are supplied (154, 233, 235).

He is aware that some of these subterranean reservoirs contain fish,

about which he has some incredible tales to tell. He makes mention

of rivers that sink underground and reappear, as if a matter for

great astonishment. But examples of it may be found in many limestone

districts, where the solution of the rock by underground water has

given rise to tunnels, passages, and caverns into which, when their

roofs give way, surface streams may be engulfed, to break out again

from other openings at lower levels (141). The author concludes this

part of his argument by asking if anybody is ignorant that there are

some standing waters which have no bottom, whence, he contends, it is

shown that this water is the perpetual source of large rivers.

The various kinds of taste possessed by natural waters are then

discussed, and some marvellous illustrations are given of their

effects. Allusion is made to medicinal springs, to petrifying

waters, to some with extraordinary dyeing properties, and to others

with neither taste nor smell, but rapidly fatal to the drinker by

immediately hardening and binding the intestines. Reference is also

included to certain kinds of springs, of which the volcanic tracts of

Italy supply good examples. Such were those which killed visitors who

peered down into the caverns where their waters lurk, and suffocated

birds that flew over them. Doubtless many tales were told of the

effects of such emanations of carbonic acid gas, like that of the

Grotto del Cane which, near Naples, still preserves their classic

reputation (134, 261). Again, the same volcanic districts furnished

instances of warm, sometimes even boiling, springs, and in alluding to

them the author quotes the opinion of Empedocles, who was doubtless

familiar with them in Sicily. To complete his record of marvels, the

author cites some lakes on which islands float to and fro, of which

good illustrations, due to a matted growth of vegetation, were then

well known in the Vadimonian Lake (Lago di Bassano),[113] and he

mentions other lakes in which he had equal faith, with water so heavy

that brickbats would float upon it, and nothing, however heavy, not

even hard solid stones, would go to the bottom.

[113] Pliny, _Hist. Nat._ ii. 96. Pliny the Younger, _Epist._ viii.

20.

Seneca is inclined to agree with some philosophers that certain rivers

of peculiar and inexplicable character were created along with the

world, and he specially cites the Danube and Nile as examples, these

vast streams being too remarkable to have had the same origin as other

rivers. Accordingly he reserves the Nile for consideration in a later

part of his volume (166). There is another kind of water which, with

his Stoic brethren, he places at the beginning of the world--the great

ocean and every sea that flows from it between the lands. Yet he found

no place in any part of the treatise for a discussion of the phenomena

of the ocean.

The Book closes with a vivid description of the probable catastrophe

by which the end of the world will be brought about. That the present

condition of things will be swept away to make room for another and

better race of men he assumes as a matter of certainty, and he tries

to picture by what physical means the destruction will probably be

effected. He is certain that it will be by no one agency, but that

all the energies of the world will be called forth to compass the

destruction of the human race, nothing being difficult to nature,

especially when she is hurrying towards her end. The picture which

is given of the progress of the great deluge forms by far the

most striking piece of writing in the volume. It ends somewhat

inartistically in some gibing criticism of a quotation from Ovid. But

the poetic afflatus had not been quite quenched. The author immediately

returns to the subject in the succeeding and final chapters, and after

enumerating the different agencies that may be called out to effect the

destruction of the world, he draws a lurid scene when a single day will

see the burial of the whole human race.[114] After this act of divine

wrath has been accomplished, the waters will disappear below ground,

the sea will retire to its own abode, and on the renovated earth every

animal will be created afresh, and a new race of men will be installed,

ignorant of sin and born under better auspices.

[114] So Lucretius:

... maria ac terras caelumque--

una dies dabit exitio.

--_De Rer. Nat._ v. 92, 94.

BOOK IV

This section of the treatise begins with a denunciation of flattery

and ends with another against luxury. Neither the preface nor the

concluding chapter have any obvious connection with the text between

them. It is curious to note that while Seneca here warns his friend

Lucilius against flatterers, and inculcates how their approaches are

to be met, he himself in this very volume perpetrates four pieces of

flattery to the despicable but all-powerful Nero. He quotes a prosaic

line from a poem of the emperor’s, which he characterises as “most

elegant” (_disertissime_, 25). He refers to Nero as most devoted to

truth as well as to the other virtues (235); he refers to the advent

of a comet which appearing in Nero’s reign had redeemed these heavenly

bodies from their evil repute (290), and he describes that reign

as “most joyous” (_laetissimus_, 294). The old courtier, so long

habituated to the language of flattery, was perhaps hardly conscious

that he was here making use of it, or he may naturally have reflected

that at a time when the emperor had ceased to bear him any good will,

the absence of the customary adulation might cause as much offence as

if a direct insult were intended.

When from his ethical lecture he turns to resume his physical

disquisitions, it is the mysterious Nile to which he devotes attention.

After a brief contradiction of the statement of some philosophers that

the Nile and the Danube are similar in their characters, he enumerates

some of the well-known peculiarities of the river of Egypt. A problem

which greatly exercised the minds of the philosophers of antiquity, and

which has only been finally solved in our own day, was the cause of

the annual rise of the Nile on which the fertility of Egypt depended.

Seneca says with justice that if the point of the river could be

ascertained where the rise begins the question would be settled. He

does not appear to have known much about the river, for he believed

that the water is for the first time collected into a single channel at

Philae. In his account of that place and of the cataract there (168,

169), he speaks of the river’s egress from Ethiopia, and of deserts

which are crossed by the trade route to the Red Sea. In a subsequent

part of the treatise he gives the interesting and important information

that he had himself seen and conversed with two centurions who had

been despatched by Nero to discover the source of the Nile (235). From

them he learnt that they had penetrated far into the heart of Africa,

and had reached a region of illimitable marshes where the river was so

covered and impeded with vegetation that neither on foot nor by boat

could it be ascended. There can be no doubt that these enterprising

explorers had come to the _sudd_, which in recent years has been found

so serious an impediment to navigation. They informed Seneca that in

the marsh region they had seen with their own eyes “two rocks from

which an enormous body of the river came out.” There are apparently no

rocks along the course of the Nile in the present marsh region, which

is a vast flat, and it is therefore difficult to conjecture to what

the two military surveyors allude. Possibly they saw the mouth of some

affluent of the main stream such as the Khor Adar, or the _sudd_ may

have extended further north than it does now.

Seneca’s account of the Nile derived from travellers and previous

writers gives a clear summary of what was then known about the river,

but of more interest is his discussion of the opinions that had been

propounded before his time as to the cause of the annual rise. He

first quotes the view of Anaxagoras, shared by the Greek tragedians

and widely accepted, that this rise was due to the melting of snow on

the uplands of Ethiopia. This idea he cogently combats by adducing

various kinds of evidence of the great warmth of the climate in those

southern regions. Some of these proofs, indeed, are exaggerations, as

where he affirms that silver is unsoldered or melted. But one of his

proofs, drawn from the habits of the animals of the country, is worthy

of notice. He remarks that no hibernating creature is found there, and

that even in midwinter the serpent is seen above ground. He argues that

in Africa, as in Europe, melting snow would swell the rivers in spring

and early summer, whereas the Nile flood continues to rise later during

four months.

In a subsequent part of this treatise (235) allusion is made to an

explanation which had been given of the rise of the Nile, that it is

due not to the fall of rain from above but to the outflow of water

from within the earth, and it is in connection with this opinion that

he cites the experience of Nero’s two centurions above referred to, as

if he were disposed to believe that what these explorers saw was really

a vast body of water issuing from underground.

The opinion of Thales is next criticised that the Etesian or northerly

winds drive the waters of the Mediterranean against the mouths of the

Nile and consequently pond back the waters of the river. This view was

of course entirely erroneous, but though Seneca rejects it, he does not

seem to have quite understood it, for he argues that, coming from the

same quarter as the winds, the Nile water should not have been turbid,

but clear and blue, like that of the sea. In commenting upon the futile

support given by Euthymenes of Marseilles to the idea of Thales, Seneca

throws light on the wide extent to which the coasts of the outer sea

had then been made known by trading vessels.

In rejecting another explanation proposed by Oenopides of Chios, the

author shows that he is aware of the fact that caves and wells are

warm in winter and cool in summer, and that he has partly divined the

reason, when he states that in winter they are warm since they do not

admit the frosty air from without and in summer they feel cold because

the warm air from outside has not penetrated into their recesses. He

returns to this subject in Book VI. (241).[115]

[115] The various ancient interpretations of the cause of the Nile’s

annual rise are succinctly given by Lucretius (_De Rer. Nat._ vi.

712–37), but he does not indicate a preference for any one in

particular, though he devotes most space to the influence of the

Etesian winds.

After mentioning and dismissing a grotesque suggestion of Diogenes

of Apollonia, Seneca suddenly drops the discussion of the Nile and

passes on to the subject of hail. It is obvious that there is here a

serious gap in the text. It is not probable that he meant to leave off

his examination into the probable sources of the Nile without stating

his own view of a matter which had been so long the subject of wonder

and debate. Either, therefore, he never completed this section of his

treatise, or a portion of the work has been lost.

The remainder of Book IV. is taken up with a desultory discussion of

the subjects of hail and snow, written when the author must have been

in a somewhat frivolous mood. He begins by telling Lucilius that if

he were to assert that hail is produced as ice is with us, a whole

cloud being frozen, he would be rather audacious. So he will imitate

the chroniclers, who after they have told a great many lies, refuse

to be responsible for some one statement, and refer for its truth

to the authorities. If, therefore, his friend doubts his word, he

will call in Posidonius, who will tell him that hail is formed from a

watery cloud just turned into liquid. No teacher is needed to explain

why pellets of hail are round, for all drops take that shape. Hail is

nothing else than suspended ice, and snow is suspended hoar-frost.

In this light vein Seneca thinks he has finished the subject and

might dismiss it, but he cannot resist the temptation to continue the

persiflage a little further. He quotes in a bantering style some of the

opinions of his brother Stoics, and after this long preamble begins

an inquiry into the distribution of density and temperature in the

atmosphere.

It would have been interesting had he seriously and fully stated what

was known or surmised on this last topic, but he dismisses it in three

short chapters. We learn from these that he regarded the air to be

densest next the earth, and that as all things retain heat better

the denser and more compact they are, so the air becomes less warm

in proportion to its height (184).[116] The opinion of some persons,

that the air on mountain summits ought to be warmer because they are

nearer the sun, is sagaciously controverted, and the insignificance

of all inequalities on the surface of the earth in comparison with

the distance from the earth to the sun is forcibly expressed and

illustrated.

[116] This view hardly agrees with what is expressed in Book II. (60,

61), but it more accurately expresses the fact.

The subject of snow and hail is briefly reintroduced at the end of the

Book, probably for the purpose of affording a convenient introduction

to the invective against luxury which fills the concluding chapter. The

preservation of snow in ice-houses, and its use in the reparation of

jaded appetites by cooling drinks, calls forth a denunciation of the

young rakes of his day, which closes the discussion.

BOOK V