Seneca, Naturales Quaestiones

49



EVERY inquiry into the nature and constitution of i
the universe falls into three divisions astronomy,
meteorology, and geography. The first investigates
the nature of the heavenly bodies, the size and
shape of the fires that ring-in the world. It inquires
whether the heavens are solid, composed of strong
rigid material, or woven of a fine thin stuff; whether
they receive or impart motion ; whether the heavenly
bodies are beneath them or fixed in their texture ;
in what manner the sun maintains the succession
of the seasons ; whether he returns upon his track
or not, and all the other questions of a similar
character. The second division deals with what lies 2
between heaven and earth, to wit, clouds, rain, snow,
and

Thunder that frights the heart of man :

in short, all that the atmosphere does or suffers.
This subject is called meteorology (sublimia raised
on high), because it deals with phenomena exalted
above the low earth. The third part inquires
about waters, lands, trees, crops, or to use a legal
phrase, everything that is contained in the soil.

How comes it, you ask me, that you have put the 3
question of earthquakes in the division under which
you are going to treat of thunder and lightning ?
For that is my plan. Well, the earthquake is due

51



52 PHYSICAL SCIENCE BK. 11

to air, and air is the atmosphere in violent motion.
Now, though the air may enter the earth in order to
produce earthquakes, the treatment of earthquakes
does not fall under geography, but more properly
belongs to meteorology, which deals with the sphere
to which nature has assigned the atmosphere. I
can tell you something that will sound stranger
still : I must speak of the earth when dealing with

4 the heavenly bodies. Why ? you ask. For this
reason : we discuss in their own proper place, as
part of geography, the properties of the earth, for
example, whether it is broad, projecting unequally
in a huge bulge to one side, or whether it all assumes
the shape of a ball, gathering up its parts into a
globe ; whether it binds its waters or is itself bound
by them ; whether it is an animal or a lifeless mass
without feeling, full of air no doubt, but not its own

5 breath. These, and all other questions of the kind, as
often as they crop up, will be relegated to geography,
and be placed in the lowest category. But when
the question comes to be the situation of the earth,
the part of the universe in which it has settled, its
position with respect to the heavens and heavenly
bodies, then the inquiry will take its place in the
higher category, 1 and obtain higher rank so to speak.



II

HAVING described the three divisions into which all
the material of nature falls, I must add a few general
remarks on the subject. And this must be premised,
that the atmosphere belongs to the class of bodies
that possess unity. What exactly this means, and

1 Viz. that of the heavenly bodies which constitute the subject matter
of astronomy.



ii " UNITY " IN MA TTER 5 3

why it must be laid down as an axiom, will
appear if I go back a little, and entering more
fully into the subject, tell you that certain bodies
are continuous, and certain formed by a union of
different elements. 1 Continuity may be defined as 2
unbroken union of parts one with another. Unity
is continuity without a break ; it is the contact of
two bodies joined to one another. There can be no
shadow of doubt that of the bodies around us which
we see and handle, and which are either perceived
or perceive, certain are composite. They are so 3
either through nexus or through mere accumulation ;
take as illustrations a rope, corn, a ship. Again,
there are bodies that are not composite, as a tree, a
stone. You must, therefore, grant that likewise
among the objects that elude sense, and are grasped
only by thought, some are possessed of unity 2
[while some arise from junction of parts]. See
how careful I am of your susceptibilities. If I 4
had chosen to employ the jargon of philosophy,
I might have got out of the difficulty by merely
saying "united bodies." You must, in turn, be duly
grateful for this concession to your weakness ! What
am I driving at ? This : if at any time I speak
of " unity " in this connection, bear in mind that it
is not used of number, but has reference to the
composition of a body that coheres through no
external aid, but by its own unity. To this category
the atmosphere belongs.

1 This difficult passage, according to Gercke s text, runs : You will under
stand the meaning of this, and the necessity for my axiomatic position if I
take up the argument a little farther back, and say that there is one kind
of body possessing unity, another that is continuous, and another that is
formed by junction. For junction is the contact of two bodies joined one to
another, continuity is the uninterrupted joining of parts one to another, unity
is continuity without junction (i.e. without a break).

2 That is, are not composite.



54



PHYSICAL SCIENCE BK. n



III

1 THE universe embraces all the objects that fall, or
that can fall, under our cognisance. Of these some
are its parts, the remaining ones must form its
material. Nature, just like every manual art every-

2 where, requires material. Let me make this a little
plainer. In ourselves the parts are hand, bones,
sinews, eyes ; the material is the sap of the digested
food, which will be distributed for the nourishment
of the parts. Again, blood is in a certain sense a
part of us, but still it is material as well. For it
goes to form other parts, and, none the less, it is
among the parts that go to make up the whole
body.

IV

1 So the atmosphere is a part, a most necessary one,
of the world. This it is that joins heaven and
earth, separating highest and lowest in such a way
as yet to unite them. It separates by coming in
between, it unites by rendering possible communica
tion between the two. It transmits to the higher
regions what it receives from the earth ; and again,
it transfuses terrestrial objects with the influences
of the heavenly bodies. I call it a part of the
world in the same sense as animals and trees are

2 parts. The whole class of animals and trees
forms part of the universe, since it has to be taken
in to make up the whole, and without it the universe
is not complete. A single animal or tree is a quasi-
part : though it is lost, that from which it is lost is
still entire. Now the atmosphere, as I have



iv WORLD- EARTH ATMOSPHERE 55



been saying, adheres both to sky and earth. In
both it is inborn. Whatever is an inborn part of
anything else possesses unity, for without unity
nothing can be born.



THE earth is at once part and material of the world, i
You are not, I think, more likely to ask why it is a
part than why the sky is a part. The one is just as
essential as the other to the existence of the whole,
which they go to make up, and from which [from
the one no less than from the other] 1 sustenance is
provided for all animals and crops and stars. From 2
the earth all the strength of every man, all the
energy of the world with its ceaseless demands, are
supplied. Hence proceeds the force that, by day
and by night, sustains in their labours so many stars,
so active and so eager, and that provides their food.
The universal nature derives from this source what
suffices for its nourishment. The world has appro
priated all that it requires throughout eternity. To
adopt a tiny illustration of a great subject : eggs
enclose within them as much moisture as they
require for the completion of the creature that is to
be hatched.



VI

THE atmosphere is in unbroken contact with the earth,
in such close juxtaposition that it must always occupy
the space that she has just quitted. It is a part, as
I have said, of the universe. At the same time it

1 The words in brackets are in all probability spurious, the addition of
some commentator. The whole passage is very uncertain.



56 PHYSICAL SCIENCE BK. n

receives all that the earth sends forth for the nourish
ment of the heavenly bodies ; so that, of course, it
should be understood in this connection as material
rather than part. It is these earthy elements that
cause its fickleness and constant turmoil. Some
authorities believe the atmosphere to be composed
of separate bodies as dust is, but they are sadly in

2 error. For there can never be internal effort in a
body held together in any other way than by
unity, 1 since the elements must be in agreement in
order to contribute their united strength toward the
tension. Now, the atmosphere, if assumed to be
cut up into atoms, must be dispersed. Scattered
elements cannot hold together as one body. But,
as a matter of fact, the tension of the atmosphere is
proved by inflated objects that will not yield to a
blow. It is proved, too, by weights carried up to a
great height merely by the support of the wind. It
is proved by the sound of voices sinking or swelling,
according to the stirring ( = vibration) of the air. For

3 what is voice save tension of the air moulded by a
stroke of the tongue so as to become audible ?
What is all running and motion ? Are they not the
effects of tense air ? This it is that imparts strength
to the sinews, and endows the runner with his speed.
When, being violently stirred, it has twisted itself
into an eddy, it uproots trees and woods, carries

4 aloft and shatters whole buildings. When the sea
lies all peaceful, the air raises it in waves. Or, to
descend to less violent manifestations, what song
can be sung without tension of breath ? Or, take
horns and trumpets, or those organs that by means
of hydraulic pressure can produce a greater volume
of sound than the mouth is capable of doing : is it not

1 Or, except in a body of uniform texture.






vi ATMOSPHERIC "TENSION" 57

through atmospheric tension that they display their
functions ? Or, let us note what an enormous force 5
is exerted in secret by quite tiny seeds, whose small-
ness has allowed them to find a lodgment in the
clefts of stones. Their slender diminutive roots
gather strength enough to dislodge huge boulders,
split statues, and cleave crags and rocks. And to 6
what is this due but air tension, without which
there is no strength, over which no strength can
prevail ? The unity of the atmosphere may, in fact,
be inferred from the mere coherence of our bodies.
What else is it that holds them together save air ?
What else is it by which the soul is stirred (literally,
moved) ? l What constitutes that motion if it be 7
not tension ? What tension can there be except
from unity? What unity could there be unless it
were in the air ? What else, too, brings forth from
the earth its fruits and slender grain, and sets erect
the verdant trees, and stretches out their branches,
or sets them on high, but the tension and unity
of air?



VII

SOME writers believe that the air is rent and sepa- i
rated into small parts with void spaces, as they
suppose, between. They consider the easy flight of
birds through it a proof that it has not a compact
body, but has large empty spaces : fowls, great and
small, pass through it without difficulty. But this is
a mistake. For water also affords the same easy 2
motion, and there is no doubt of its unity. When
it receives bodies, it always retreats in the direction

1 Nisard translates, What imparts movement, in man, to the vital
principle ?



58 PHYSICAL SCIENCE BK. n

opposite to them. This the Stoics call displace
ment, in Greek it is peristasis, 1 which takes place
in air just as it does in water. For it literally stands
round every body by which it is pressed. There is
no need to assume an admixture of vacuum with
the element. But more of this another time.



VIII



1 FROM what has been said it must be inferred that
in nature there exists a principle of activity of
enormous force. For there is nothing that does not
become more active through tension ; and it is no
less true, nothing will be found capable of tension
from another body unless it have in itself capacity of
tension. 2 In the same way we say that nothing
could be moved by another body without possessing
the quality of mobility in itself. But what element
can be conceived more likely to possess tension in

2 itself than air? Will any one deny that it can be
subject to that force after seeing how it tosses
about the earth with its mountains, houses, and
walls and towers, and great cities with their in
habitants, seas, and whole coast-lines ? The tension
of air is proved, too, by its velocity and expansion.
Illustrations of these properties are common : in an
instant the eye extends its sight over many miles;



= a standing around. The Latin equivalent in the text is
circumstantia, rendered "displacement."

2 The reading at several points is so uncertain that one cannot be at all
sure of the meaning. Probably the whole passage is very corrupt. So far
as the main theme is concerned, the argument seems to be, As mobility is a
presupposition of motion, so tensibility is a necessary condition of actual
tension produced in a body by another body. One is tempted to employ
"elasticity," but the term contains implications with which the author was
apparently unfamiliar.



vin FURTHER PROOFS 59

a single voice resounds at the same moment
through whole cities ; light does not creep forth
little by little, but is shed simultaneously over the
whole world.



IX

AGAIN, how could water be subject to tension i
without the aid of air ? You entertain no doubt, I
suppose, that the jet of water in the amphitheatre,
which is thrown from the centre of the arena to
the highest pinnacle, is accompanied by tension of
the water ? And yet neither hand 1 nor any other
engine can send or force water more effectively
than air. It lends itself readily to the influence of 2
the air, by the compelling force of which within the
pipe it is raised. Its nature is to flow down, but
under pressure it mounts and accomplishes great
results contrary to its nature. Yes, and do not
heavily laden vessels also prove that it is the
resistance of air, not of water, that prevents their
sinking ? The water of itself would give way,
and would be unable to bear up the burthens, were
it not itself upborne. So, too, a quoit thrown from 3
a height into a pond does not fall straight in, but
recoils, and that merely because the air bears it
back. In what way, again, could the sound of a
voice be transmitted through the thick barrier of a
wall unless the solid masonry contained some air
to receive and transmit the sound from without ?
The tension of the air, of course, affects not only
what is exposed, but what is concealed and enclosed
as well. This is easy for it to do, since it is never 4
divided, but maintains an unbroken continuity even

1 A conjecture widely adopted gives "crane."



60 PHYSICAL SCIENCE BK. n

through the centre of objects by which it appears
to be parted. The interposition of walls and high
mountains renders it impassable by us, but is no
obstacle to itself. The air is there all the same, 1
but a portion is enclosed and we cannot follow it
through ; that s all.



1 THUS the air passes through the middle of an
obstacle by which it is apparently divided. It not
merely surrounds and encircles all objects, but
permeates them likewise. It is shed abroad from
the bright ether on high down to the very earth.
It is nimbler and rarer and more exalted than the
earth, and no less so than the waters of earth ;
but, on the contrary, it is thicker and heavier than
the ether, and is naturally cold and dark, its light
and heat coming from without. It is not of the
same specific quality in every region, but borrows

2 its qualities from its surroundings. The highest
part of it is extremely dry and hot, and so, very
rare also, from the proximity of the eternal fires,
the endless motions of the stars, and the constant
revolution of the heavens. But the lowest portion
next the earth is dense and dark, because it forms
a receptacle for the exhalations of the earth. The
intermediate portion, in dryness and rarity, runs
to neither extreme as compared with the highest

3 and lowest strata, but is colder than either. The
reason is this : The higher parts are affected by
the heat of the heavenly bodies that are close by;
and again the lower parts are warmed in the first

1 The general sense is clear, but the particular text is uncertain.



x LA YERS OF A TMO SPHERE 6 1

place by the earth s breath which is charged with
heat, while in addition the sun s rays are reflected
from the ground, and as far as the reflection extends
it renders the atmosphere kindlier and more genial.
Besides, the temperature of the lower air is raised
by the warm breath of all animals, trees, and
crops, whose life is dependent on heat. Add
to this also fires on the earth, not merely the
artificial ones about which we know, but also those
concealed beneath it, some of which have ere this
broken out, and myriads of which are blazing away
in the hidden depths incessantly. Add, too, that all
the fertile parts of the earth have some degree of
heat which is exhaled into the air : heat is a con
dition of generation, the frigid is sterile. So, then,
the middle portion of the atmosphere being remote
from all these influences abides in its native cold :
for air is by nature chilly.



XI

SUCH being the divisions of the atmosphere, I
may observe that in its lowest layer it is most
variable, unstable, and changeful. It is near the
earth that the air is, so to speak, most enterprising
and most long-suffering, as it tosses or is tossed.
But withal, it is not all affected in the same way,
but at different times at different points its different
parts are in unrest and turmoil. The reasons of
the changefulness and inconstancy are in part
derived from the earth : her position turning hither
and thither is a potent factor in determining the
quality of the atmosphere. Other reasons are due
to the heavenly bodies, chiefly the sun, whose course



62 PHYSICAL SCIENCE BK. n

directs the year, whose solstices determine winter
and summer. Next in importance is the moon s
influence. But even the other stars produce an
effect alike on the earth and on the air that rests
upon the face of the earth. Their rising or their
corresponding setting and their disturbances cause
now cold, now rain, now other damage such as
earth is subject to.

It was necessary for me to make these preliminary
remarks before going on to speak of thunder and
thunderbolts and lightnings. For as these pheno
mena occur in the atmosphere, I had to explain the
nature of the latter, that it might more readily appear
what active or passive capacities it possessed.



XII

1 THERE are, I have just said, three phenomena
lightnings, thunderbolts, thunderings : the last is
simultaneous in occurrence with the others, but its
sound reaches us subsequently. Lightning (i.e.
sheet) merely reveals fire, the thunderbolt (forked
lightning) actually despatches it on its mission.
The former is, so to speak, a threatening and feint
without a blow, the latter a stroke and a blow.
There are some of the facts connected with the
phenomena of thunder and lightning on which
there is general agreement, others on which there

2 is much diversity of opinion. For example, there
is agreement that they occur in the clouds and
issue from the clouds ; further, it is agreed that
lightning of both kinds is either composed of fire
or at any rate presents the appearance of fire.
But to pass on to the points which are disputed



THUNDER AND LIGHTNING 63



some authorities believe that the fire is actually
resident in the clouds, some that it is merely pro
duced for the occasion, and that it does not exist
until it issues out. But yet there is no agreement
as to what brings out the fire. One explains it 3
as due to light. Again, a certain author says that
the sun s rays accumulate through recurrent inter
section, and kindle the fire. Anaxagoras asserts that
it is distilled from the ether, that from such heat in
the sky many sparks fall which the clouds enclose
and retain for a long time.

Aristotle supposes that the fire does not gather
in the clouds any long time previously, but rather
that it bursts out at the same instant as it is formed.
His opinion runs thus : Two elements of the world, 4
land and water, lie in its lower part ; each exhales
its peculiar emanation. The vapour of earth is
dry, resembling smoke, and produces wind, thunder,
and lightning ; the breath of water, on the other
hand, is moist, and produces rain and snow.
But that dry vapour from the earth, to which
[as mentioned] winds owe their origin, on account
of its accumulation in large masses, is subject to
violent lateral pressure when it is condensed for
the formation of clouds. Thereupon it strikes the 5
adjacent clouds over a larger surface, and the
blow reverberates loudly [in thunder]. The effect
is analogous to that produced by the crackling of
flame from the moisture contained in green un
seasoned firewood. In this case the air enclosed
in the wood has some moisture in it, and when it
accumulates it bursts out in the flame. So like
wise the air which, as I said a little ago, is driven
out through a collision of two clouds, cannot burst
or leap out without noise. The sound varies 6



64 PHYSICAL SCIENCE BK. n

according to the variety of impact in the clouds ;
the larger cavity in some clouds, the smaller in
others account for the variety. That air violently
driven out is fire, which is called sheet lightning
when it forms a fitful flame of no great violence.
We see the flash before we can hear the sound :
eyesight is swifter than hearing, and far outstrips it.



XIII

1 THE mistakenness of the opinion that the fire is
stored up in the clouds may be inferred from many
considerations. For example, if the fire merely
falls from the sky, why does it not do so every day
from the glowing mass that is constantly up there ?
Then, again, the theory gives no explanation of the
downward course of the fire, an element which
naturally rises. Fires on earth from which embers
fall belong to a different category ; the embers
possess a certain amount of weight, which carries
them down. Fire cannot descend in the same way,

2 but must be forced or conducted down. Nothing
analogous to a terrestrial fire can take place in that
pure ethereal fire which contains nothing that can
carry it down to earth. Otherwise , if any portion
of it fall down, the whole is endangered ; for
anything susceptible of gradual diminution piece
meal may evidently also fall in a mass. Besides, if
an element whose lightness habitually prevents its
fall contain any weight in its hidden depths, how
could it maintain itself in the place whence it fell ?
But, it is urged, are not certain forms of fire wont
to descend into the lower parts of air very much
like these bolts of lightning that we are investi-



xin FIRE IN THE CLOUDS 65

gating ? Admitted. Only they are conveyed, they 3
do not proceed of themselves. Some force not
resident in the ether carries them down. For in
the ether no violent compulsion, no breach, no
interruption of the wonted continuity, can occur.
It preserves a fixed succession ; its fire cleansed of
impurity claims the upper regions as its own, and
performs its functions in preservation of the
universe with beautiful precision. It cannot leave
its place, no, nor even be thrust from it by external
force, because no disturbing body can find lodgment
in ether. Its fixed and ordered composition renders
conflict impossible.

XIV

SOME of your friends the philosophers, a critic may i
say to me, in giving an explanation of shooting
stars have told us that some parts of the atmosphere
contract fire which is drawn from these same
higher regions, and that the fires are kindled by the
glow of the ether. Yes, but I reply that it makes
all the difference whether the fire is alleged to fall
from the ether, which is incompatible with its
nature ; or whether it is asserted that from its
fierce glow the heat leaps the boundary between it
and the lower regions, firing them by its power.
For on the latter assumption, the fire does not fall
from the upper region, which is impossible, but is
kindled in the lower. Surely, too, when a widely 2
spread conflagration occurs in one of our cities, we
see detached blocks which have for long been
heated by the fire from a distance at last catch
fire of themselves. So in the upper atmosphere,
which is endowed with the power of drawing fire,



66 PHYSICAL SCIENCE BK. n

in all probability there are cases of ignition from
the heat of the superposed ether. In nature there
is never a sudden transition from one element to a
totally different one. Hence there must be some
congruity between lowest ether and highest atmo
sphere ; conversely highest atmosphere cannot be
wholly dissimilar to lowest ether On the confines
the two elements pass so imperceptibly into one
another that at a particular point there might
well be doubt whether one is in atmosphere or in
ether.

XV

SOME of the Stoics believe that air, being inter
changeable with other elements such as fire and
water, does not derive from without a fresh cause
of fire ; it kindles itself by its internal motion.
Then in dissipating masses of thick, compact clouds
it necessarily emits a loud noise from the .bursting
of such large bodies. Besides, the very conflict
of the resisting clouds contributes to the energy of
the fire. In the same way the hand contributes to
the cutting power of an instrument, but the actual
cutting is done by the steel.



XVI

LET me now explain the difference between the
flash and the bolt of lightning which you naturally
wish to know. The flash is the fire widely spread
out, the bolt is the condensed fire hurled with
violence. Let me use a homely illustration. We
sometimes join our two hands in order to take up



xvi OTHER MISTAKEN EXPLANATIONS 67

water in them ; then we squeeze our palms together
and squirt out the water like a syringe. Imagine
something like this to take place in the clouds.
When they are compressed the restricted space
drives out the air between them, setting it on fire
at the same time, and hurling it forth like a cannon
ball. The missiles from our balistae l and scorpions l
give forth a loud noise as they are hurled.



XVII

A CERTAIN number of writers are of opinion that
the air of itself emits a report as it traverses the
cold and moist regions. Iron, they point out, when
heated cannot be dipped in moisture without noise.
A mass of heated metal when plunged in water
causes a loud sputtering as it is cooled ; so,
according to Anaximenes, air meeting cloud produces
peals of thunder ; then as it rushes struggling
through the obstructions that bar its way it kindles
the flame of lightning merely by its escape.



XVIII

ANAXIMANDER refers all the phenomena of thunder
to air. Peals of thunder are, he says, the sounds
of blows on a cloud. He explains the inequality of
the peals by the inequality of the blows. To the
question, why it thunders in a clear sky also, he
answers that even in absence of cloud the atmo
sphere is shaken and rent by the bursting forth of
air. But why is there thunder sometimes and yet

1 The ancient counterparts of cannon.



68 PHYSICAL SCIENCE BK. n

no lightning ? The rarity and feebleness of the air
render it incapable of producing flame, while yet
sufficient to produce sound. Lightning, according
to him, then, is really a disturbance where the
atmosphere is merely parted and rushes hither and
thither, displaying a faint fire that will not issue
from its place. As for the thunderbolt, it is the
career of the more active and denser air.



XIX

1 ANAXAGORAS says all the phenomena correspond
to the descent of some force from the ether to the

2 lower regions. So when the fire encounters cold
clouds it emits a sound ; when it cleaves them there
is a flash ; less violence in the fires produces
lightning, greater, thunderbolts.



XX

1 DIOGENES of Apollonia asserts that thunder arises
in some cases from fire, in some from air. Fire
precedes those it produces, to herald them. Those
that are attended with rattling noise, but without
flash, are produced by air. Either sound or flash,
I grant, can and sometimes does occur without the
other. Still, their powers are not distinct, each
may be produced by each. For will any one say
that air borne with great violence, when it can

2 produce sound, will not also produce fire ? Will
not every one grant, too, that fire as well as air
may sometimes burst the clouds without darting
from them, for example, if it has burst through a



xx CAUSES AND EFFECTS 69

few of the clouds, but is buried beneath an
accumulation of them ? So fire will pass into air, and
lose its shining appearance in cutting through some
cloudy obstacles and kindling what is within. Add
now another inevitable result the rush of the
thunderbolt sends out blasts of air and drives them
before it, and raises a wind behind it through
the great extent of its impact on the atmosphere.
Thus, through the vibration caused by the wind
which the fire drives in front of it, all objects
quiver before they are actually struck by the bolt
of lightning.



XXI

WE must now dismiss our tutors and try to walk i
alone as we pass on from what is admitted to what
is debatable in this subject. What is to be classed
as admitted ? It is admitted that the thunderbolt
is fire of some kind ; similarly with the lightning
flash, which is simply flame ready to become a bolt
if it had more strength. The difference between
the two is not in character but in force. The fiery
nature of the bolt is proved by its heat. Apart
from that, its effects prove it, for it has often been
the cause of great conflagrations. Forests and 2
portions of cities have been burnt to ashes by it.
Even objects that are not struck are yet seen to
be scorched, some are discoloured as if by smoky
grime. Then, again, everything that lightning
strikes has the smell of sulphur. And so it is
beyond dispute that both phenomena are a form of
fire, and that they differ merely in their method of
movement. A flash is a bolt that has not strength 3
to carry it down to the earth. And conversely you



70 PHYSICAL SCIENCE BK. n

may say that the bolt is a flash that has been
conveyed right down to the ground. It is not for
the purpose of refinement of terms that I deal at
some length with them, but in order to prove the
phenomena related and of the same category and
character. A bolt is something more than a flash.
Inverting the statement, a flash is all but a bolt.



XXII

1 Now that it is agreed that the two things are both
fire, let us see how fire arises on earth, for no doubt
the same method prevails aloft. There are two
common methods of producing fire one by striking
it out, as, for example, from a stone ; the other by
the more tedious method of friction, as when two
pieces of wood are rubbed together for some time.
It is, of course, not every kind of substance that
gives the desired result ; you must choose one
suitable for giving out fire, for example, laurel, ivy,
and other trees familiar to shepherds for this
purpose. Probably, therefore, clouds may in the
same way emit fire either from a blow or from

2 friction. Consider for a moment the force with which
squalls rush forth, the impetuous eddying revolu
tion of the whirlwind. Anything that encounters
a missile from an engine of war is scattered and
removed and driven far from its position. What
wonder, then, that such violence in the wind extracts
fire either from some external object or merely from
itself ? You can readily see what a glow all
neighbouring bodies grazed by its passage must
receive. But the force of storms cannot for a
moment be compared with the energy of the



xxn PRESENCE OF FIRE 71

heavenly bodies, whose immense power is beyond
question.

XXIII

PERCHANCE, too, when the wind only blows softly i
and exerts no great force, the clouds, wafted against
each other, will emit fire strong enough to show a
gleam, though not to issue from them. Less force
is required for lightning than for the thunderbolt.
We found above what a glow the friction of certain
woods caused. Now when the air, which is inter- 2
changeable with fire, [has been changed in full force
into fire and] 1 undergoes friction, it is credible and
even probable that fire is struck out, but of an
evanescent and transitory character, as it arises
from no solid material and has no fuel in which it
can lodge. It therefore quickly passes ; its duration
is no longer than its route and course ; it has
nothing to support it when hurled forth into space.



XXIV

BUT how, you ask me, when you philosophers say
that it is the nature of fire to rise, does the bolt
seek the earth ? Perhaps what you said about fire
is not true ? It seems to take its course down as
well as up.

Both my statements, I reply, may be true. Fire
naturally does rise and mounts if nothing prevents
it, just as water naturally gravitates downwards.
But water if affected by a force which drives it
uphill is pressed up in the direction from which
it was precipitated in rain. In like manner the same

1 These words seem of more than doubtful genuineness.



72 PHYSICAL SCIENCE BK. u

force as launched the bolt from the cloud causes it
to fall to the ground. Something of the same kind
happens to these celestial fires as to trees when
bent. The topmost branches if slender may be
dragged down so as to touch the ground ; but when
you let them go, they rebound to their original
position. You must not regard the condition which
an object involuntarily assumes as characteristic of
it. If you allow fire to go where it will, it will
return to the sky, the abode of all the lightest
bodies. But when there is anything to carry it
down and divert it from its natural course, that is
not a mark of its disposition but a token of its
subjection.



XXV

You and your friends say, an objector interposes,
that clouds emit fire through mutual friction
when they are moist, indeed wet. How can such
clouds produce fire, which is no more likely to be
generated by a cloud than by pure water ?



XXVI

WELL, first of all, the fire which is thus produced is,
as it is found in the clouds, not water, but thick
air, adapted for the generating of water ; it is not yet
changed into it, but is already inclined toward, and
ready for, the change. There is no ground for
supposing that water is first gathered in the clouds
and afterwards shed from them. It falls simultane
ously with its formation. But in the second place,



xxvi FIRE AND WATER 73

though I grant that the cloud is moist and charged
with fully formed water, still there is nothing to
prevent fire being drawn from what is moist, yes
and what will surprise you more to learn out of
pure moisture. Some authorities have actually 2
affirmed that nothing can be converted into fire
without a prior change into water. A cloud, then,
without prejudice to the water it may contain,
may emit fire at some part of it, just as often one
end of a log is blazing while the other exudes
moisture. I do not deny that fire and water are
opposing elements and that the one destroys the
other. But where the fire is stronger than the
water it wins the day. On the other hand, where
there is a superabundant supply of moisture, then
fire is powerless. That is why green wood won t
burn. The result depends, therefore, on the quantity
of water present. If it is small, no effectual resist- 3
ance is offered, the fire is not prevented. Why,
according to Posidonius account, when an island
rose in the Aegean Sea long ago in our forefathers
days, the sea was lashed into foam for a long time
previously and sent up smoke from its depths. At
last fire was emitted, not continuously, but in flames
shooting out at intervals, after the fashion of
thunderbolts, just as often as the fervent heat of
what lay below had overcome the weight of water
above it. By and by boulders were thrown up and 4
rocks, part of them still unimpaired, which the air
had thrust out before their calcination, part of them
corroded by the fire and changed to light pumice ;
at last the cone of a blasted mountain issued from
the waves. Subsequently, there was an addition
to its height, and the rock grew in extent into
an island, The same thing happened within our



74 PHYSICAL SCIENCE BK. n

own recollection during the second consulship of
Valerius Asiaticus.

5 Why have I narrated these incidents ? My
purpose was to make it evident that neither is
fire necessarily extinguished by having the whole
sea poured over it, nor its violence prevented
from bursting out by the weight of huge waves.
Asclepiodotus, a pupil of Posidonius, has left it
on record that the height to which the fire
mounted, after overcoming the resistance of the
waves, was a hundred fathoms. Now, if such a
huge mass of water was unable to overcome the
force of the flames that rose from its depths, how
much less can the thin, dewy moisture in the clouds

6 extinguish fire in the atmosphere ? In short, the
moisture of the clouds is so far from presenting any
obstacle to the formation of fire that lightning is
never seen to flash except when the sky threatens
rain. A clear sky has no bolts to hurl. No terror
of that sort proceeds from a bright day, nor for the
matter of that from a night that is not enveloped in
cloud. But what ! I hear some one say. Does it
not sometimes lighten in a calm night when the

7 stars are visible? It does, but you must remember
that there are clouds all the same in that quarter
whence issues the flash ; only, the earth s hump
does not allow them to be seen by us. Add, too,
what is quite possible, that low clouds near the
earth may produce fire through friction. This fire
when forced up to the upper regions becomes
visible in the clear bright part of the sky, but none
the less its place of origin was in the dark vicinity
of earth.



xxvii VARIETIES OF THUNDER 75



XXVII

SOME writers have distinguished different kinds i
of thunder, saying there was one kind with a deep
growl like that which precedes an earthquake,
when the wind moans and tries to burst its prison
walls. Let me tell you how they suppose this
kind of thunder to arise. When the clouds have
enclosed air, it rolls through their cavernous depths
and emits a hoarse, regular, continuous sound like
bellowing. So also when that quarter of the
heavens is charged with moisture, its exit is pre
vented until the thunder begins. Therefore, thunder 2
of this kind is a sure sign that rain is to follow.
There is another kind, which is sharp, and it might
be described more accurately as a crackling than
as a regular sound ; it resembles the report one
hears when a bladder is burst over some one s
head. Such thunder is the result of the breaking
up of a densely massed cloud and the release of
the air by which it was inflated. This is appropri
ately named a peal, sudden and violent. When it
occurs, people collapse and are sometimes literally
frightened to death by it ; others retain life, but are
dazed and completely lose their wits : we call them
thunder-struck, for that sound in the heavens has
quite unhinged their minds. This sound may also 3
be produced by the atmosphere shut up in a hollow
cloud being rarefied, merely through motion, and
expanded. By and by in seeking more room for
itself it resounds against the walls that envelop it.
In fact, is it not just similar to the applause given
out by the clapping of the hands? only, when the



76 PHYSICAL SCIENCE BK. n

clouds collide, the sounds may be expected to
correspond in volume to the greatness of the
encountering bodies.

XXVIII

1 BUT clouds, says some one, are seen striking upon
mountains without causing any sound. How is
that consistent with your theory? Well, in the
first place, a sound is not caused by any and every
method of cloud collision, but only when there is
an arrangement of their position suitable for pro
ducing a sound. Striking the backs of the hands
does not produce clapping, but the contact of palm
with palm does. It makes a great difference, too,
whether the clouds that strike are hollow, or flat
and extended. In the second place, the clouds
must not merely drift, as against a mountain, but

2 be driven with great tempestuous violence. Besides,
a mountain does not cut through a cloud, it merely
disperses it by displacing the successive front layers
of it. Even a bladder does not give a report
irrespectively of the method in which it emits the
air in it ; it depends on the way in which the air
escapes. If the bladder is cut with a knife, the air
is emitted without the ear perceiving it. It must
be burst, not cut, in order to give a report. The
same, I assert, holds in regard to the clouds : they
emit no peal unless broken up with great violence.

3 Besides, clouds driven against a mountain are not
broken up, but merely pour round certain parts
of the mountain, tree branches, shrubs, and rough
projecting boulders. They are rent thereby, and
emit by numerous exits whatever air they may
contain ; but there is no rattle unless the air all



xxvin CAUSE OF THUNDER PEAL 77

burst out at once. In proof of this, bear in mind 4
that the wind blowing through a tree, which cuts
it, hisses but does not roar. A broad blow, so to
speak, that dissipates the whole mass at once, is
required in order to the emission of a sound such
as is heard when there is thunder.



XXIX

MOREOVER, the atmosphere is by constitution
adapted to the transmission of sound. 1 Of necessity
this is so, since sound is nothing but an impact of
the atmosphere. The clouds that [as indicated]
are completely rent must therefore be hollow and
taut. One sees how much more resonant empty
vessels are than full, and distended ones than slack.
So this accounts for the sound of tambourines and
cymbals ; the former resound because the blow
upon the air is resisted at the farther side ; the
latter are beaten against the air directly, but unless
there were a cavity in the instrument it would not
tinkle.



XXX

SOME authors, including Asclepiodotus, are convinced
that thunder and lightning may also be produced
by the collision of certain solid bodies. Once Etna
was in violent eruption and cast up a huge quantity
of burning sand. The daylight was veiled with the
cloud of dust, and sudden night terrified the world.
On that occasion, they allege, there was much
thunder and lightning, produced, they maintain,

1 The specific word vox = voice is used in the text.



78 PHYSICAL SCIENCE BK. 11

by the concourse of dry bodies, not of clouds : with
such a glow in the firmament there probably were

2 no clouds at all. Cambyses once sent an army to
the temple of Jupiter Ammon in the desert. The
sand raised by the south wind fell on it like snow-
flakes, first covering and finally overwhelming it.
Probably on that occasion also there was thunder
and lightning, caused by the mutual friction of
the particles of sand. Such a view is not in-

3 consistent with my contention above. I have said
that the earth s exhalations contain bodies of two
kinds, dry and moist, portions of which roam
through the whole expanse of the atmosphere. So
if any heavy element be introduced, it makes a
cloud thicker and more solid than if its texture
were of pure air exclusively. Such a [solid] cloud

4 may burst with a loud report. The elements I
have mentioned, whether they have charged the
atmosphere with moist fires or with earth-sweeping
winds, must produce a cloud before they produce
a report. Dry elements no less than moist may
make up a cloud. For cloud, as we have already
said, is just a condensation of thick air.



XXXI

BUT further, if you will but open your eyes to
them, there are marvellous effects in lightning that
leave no doubt that a subtle divine power is
inherent in it. For example, coins are fused while
the purse containing them is uninjured and intact.
A sword is melted while the sheath remains. The
iron point is fused in a javelin, but the wooden
shaft suffers no damage. The jar is smashed and



xxxi MARVELLOUS EFFECTS OF LIGHTNING 79

the wine frozen, but the stiffness does not last for
more than three days. There are other no less 2
notable effects of lightning. The head of man or
other animal struck by it always points in the direc
tion whence the lightning issued : the twigs of all
trees that are struck rise straight up in the direction
of the lightning. Let me add, too, when venomous
serpents or other animals whose bite is fatal are
struck with lightning, all the poison disappears.
How, you say, can I tell that ? In the dead bodies
of poisonous animals worms are not produced. But
when struck with lightning they breed worms within
a few days.

XXXII

LIGHTNING portends the future, too. Nor do the i
signs it gives refer to only one or two events.
Often a complete series of fate s succeeding decrees
is intimated, with proof, too, plain to demonstration,
far more distinct than if it were recorded in writing.
There are differences of interpretation, however,
between our countrymen and the Tuscans, the
latter of whom possess consummate skill in the
explanation of the meaning of lightning. We 2
think that because clouds collide, therefore lightning
is emitted ; they hold that clouds collide in order
that lightning may be emitted. They refer every
thing to the will of God : therefore they are strong
in their conviction that lightning does not give an
indication of the future because it has occurred,
but occurs because it is meant to give this in
dication. Whether the indication is its purpose
or its consequence makes no difference in the
method of its occurrence. How, then, do they



8o PHYSICAL SCIENCE BK. n

3 give indication unless they are sent by God ? Just
in the same way as birds give favourable or un
favourable omens, though they are not moved on
their flight for the express purpose of meeting us.
God moves them too, it is urged. You imagine He
has so little to do that He can attend to trifles of this
sort, if you will have Him arrange visions for one,
entrails of victims for another.

4 Nevertheless, all those things are managed by
Divine agency, not, however, in the sense that the
wings of birds are immediately directed by God, or
the bowels of cattle arranged by Him in certain
forms under the priest s axe. It is in far other
way that the roll of fate is unfolded ; it sends
ahead in all directions intimations of what is to
follow, which are in part familiar, in part unknown
to us. Everything that happens is a sign of some
thing that is going to happen : mere chance occur
rences uncontrolled by any rational principle do not

5 admit of the application of divination. An event
that belongs to a series thereby becomes capable of
being predicted. But why, then, is the honour
conferred upon the eagle of giving omens concern
ing great events ? or a similar function assigned to
the raven and a very few other birds, while all the
rest give no presage by their notes ? The reason
simply is that some departments have not yet been
brought within the sphere of the art of augury, while
some are incapable of ever being brought within it,
because our acquaintance with them is too slight.

6 As a matter of fact, there is no living creature
whose movement or meeting with us does not fore
tell something. Of course, only some, not all, can
be observed. The omen lies in the observation.
So it concerns the person who directs his attention



xxxn OMENS FROM LIGHTNING 81

to it. But other things as well concern him, though
they pass unheeded. For instance, the Chaldaeans
confined their observation to the five great planets.
But do you suppose that the influence of so many
thousands of other bright stars is naught ? The 7
essential error of those who pretend to skill in
casting the horoscope lies in limiting our destinies
to the influence of a few of the stars, while all that
float above us in the heavens claim some share in
us. Perchance the lower stars exert their force on
us more directly ; and 1 the same may be true of
the stars that by reason of their more frequent
movements turn their view upon man in a different
way from that in which it is turned upon other
living creatures. But even those stars that are either
stationary or, from their velocity being the same as
that of the world as a whole, seem to be so, are
not without sway and dominion over us. Add 8
one other consideration and you have the subject
set out with due arrangement of its parts : 2 it is
not more easy to ascertain what the power of the
stars is than justifiable to doubt that they possess
such power.



XXXIII

To return now to lightning: the art relating to it falls
into three divisions its observation, its interpre-

1 Or, Turn their view upon man no less than on the other living creatures
now from one point, now from another, i.e. under more varied aspects. The
passage is doubtful. The general sense is plain : nearness, frequency of
appearance, and variety of aspect severally are or may be special factors in
determining a star s influence on the fate of man.

2 The text is corrupt and the sense more or less conjectural. Ruhkopf
suggests that the words may have been transferred from some other passage
to this. One would be inclined to suspect that adjice = add, instead of
aspice see, regard, is the correct word at the beginning of the sentence.

G



82 PHYSICAL SCIENCE BK. n

tation, its deprecation. The first has regard to the
category in which it should be placed, the second to
divination, the third to the propitiation of the gods,
whose blessings we ought to ask and whose threats
we must avert by prayer. We must ask them to
fulfil their promises, pray them to remit their
threats.



XXXIV

1 PEOPLE are convinced that lightning possesses
sovereign power, because its occurrence destroys
the force of other portents. On the other hand,
whatever it portends is regarded as unalterable, and
the appearance of no other omen lessens its
import. Anything threatened by unfavourable
entrails or inauspicious birds will be cancelled by
favourable lightning. But any warning given by
lightning cannot be defeated by opposing entrail or

2 omen. Now this belief seems to me mistaken. My
reason ? Simply that nothing can be truer than the
truth. If birds have truly foretold the future, the
omen cannot be nullified by lightning : if it can,
then it was not a true prophecy the birds uttered.
It is not bird and lightning whose force I am here
comparing, but two revelations of truth, which must
be equal in authority if they are equally intimations
of truth. Therefore, if the occurrence of lightning
destroys the indications given by priests or augurs,
there must have been a flaw in the inspection of the

3 entrails or the observation of the auguries. It is
not a question of which of the two kinds of omen
possesses the more exalted or powerful character : if
both have furnished indications of truth, they are so
far equal. You would be quite justified in asserting



xxxiv PROGNOSTICATION VALUES 83

that the power of flame was greater than that of
smoke ; but flame has just the same power as
smoke, and no more, in giving indication of the
existence of fire. So if the statement is confined
to the assertion of the greater authority of lightning
on occasions when the entrails give one indication
and lightning a different one, I shall perhaps agree.
But if the statement go on to affirm that although 4
other signs have foretold the truth, yet the lightning
stroke has destroyed all that went before and claims
credit only for itself, then the statement is untrue.
And for this reason : the mere number of the
auspices makes no difference. Fate is but one. If
it was rightly understood through the first auspice,
it is not destroyed through the second ; it remains
just the same. And so I say again it does not
matter whether the means of our inquiry ( = auspice)
is the same or different, since the object of the
inquiry remains the same.



XXXV

FATE cannot be changed by lightning. And why ? i
Lightning is itself a part of fate. Well, then, it
may be asked, what is the good of expiation and
atonement if the fates are immutable ? Let me
uphold the rigid sect that takes exception to such
rites and regards vows as but comfort to a breast ill
at ease. The fates perform their function in a
far different way from that supposed ; they are not
moved by any prayer nor changed by pity nor by
favour. The course they hold is irrevocable ; once 2
they have entered upon it they flow on by unalter
able decree. As the water of rushing cataracts



84 PHYSICAL SCIENCE BK. n

returns not upon itself, nor yet lingers, since each
succeeding wave drives headlong that which went
before ; so the order of events is rolled on by the
eternal succession of fate, whose first law it is to
abide by its decrees.



XXXVI

1 FOR what is one to understand as meant by fate ?
I suppose it is the binding necessity of all events
and actions, a necessity that no force can break. If
you believe that such a power can be prevailed upon
to change through sacrifice or the head of a snow-
white lamb, you know little about the Divine dis-

2 pensation. You say that even a wise man does
not change his mind : how much less is God a man
that he should change ? Even the wise man knows
what is best under present conditions ; to the Divine
wisdom everything is present. Still, I wish, for the
moment, to advocate the views of those who hold
that atonement should be made for lightning, and
who have no doubt that expiation is of avail, now
to remove dangers, now to mitigate them, now to
delay them.

XXXVII

i IN a little I will follow up what I have said and
show the consequences involved. Meantime we
have so much in common with the persons last
mentioned in holding that vows are of service, but
without prejudice to the power and sway of fate.
Some things are, in fact, left by the immortal gods in
such a state of suspense as to turn to the advantage



xxxvn COURSE OF FATE 85

of worshippers if they employ prayer to heaven and
take vows upon them. This, then, is so far from
being opposed to fate that it is actually a part of fate.
But my opponent argues thus : an event is either 2
going or is not going to take place. If it is going
to, then it will take place, even though you take no
vows upon you. If it is not going to, then it won t,
even though you take the vows. The dilemma, I
reply, is no valid one : you overlook an alternative
that lies between those horns of yours. This, say
I, will take place, but not unless vows have been
taken upon those concerned. This, too, one may
say, must be included in the order of fate, either
that you undertake the vows or that you do not.



XXXVIII

SUPPOSE that I surrender at discretion and admit i
that it is likewise included in fate that vows be
assuredly performed. Then for that reason they
will be performed. It is fated that a man be
eloquent, but only if he use due means and apply
himself to study. The same destiny enjoins that
he should study ; therefore he will study. Another
will be rich, but he must first go to sea. But in
the order of fate in which he is promised a great
fortune, it is also decreed that he go to sea ; there
fore he will go to sea. In regard to expiation, I 2
apply just the same principle. A man is fated to
escape danger if he expiate the threats foretold by
heaven. But it is likewise contained in fate that
he offer expiation ; therefore he will offer it.

An objection is usually urged against this view
which seeks to prove that no freedom of will is on



86 PHYSICAL SCIENCE BK. n

this assumption left to us, all sway is handed over to
fate. When I come to treat of that subject, I will
explain how, without infringing the power of fate,
3 something may still be left to human choice. For
the nonce, I have explained the point at issue, viz.
how, consistently with an order fixed by fate, perils
from prodigies may be averted through expiation
and sacrifice, inasmuch as they do not conflict with
fate, but, on the contrary, are assumed by the very
law of fate. What benefit, then, you say, can I derive
from a soothsayer? In any case I must of necessity
offer expiation, even though he be not by to advise
it. He so far does good in that he is the instru
ment of fate. In like manner, when recovery
from illness seems the work of fate, it is due at the
same time to the doctor, because the boon of fate
passes through his hands in order to reach us.



XXXIX

THERE are, Caecina says, three kinds of lightning
the counselling, the authoritative, and what is
called the ordinary. The counselling occurs before
an event, but after the design is formed. When
something is simmering in one s mind, the lightning
stroke either urges it or deters from it. The
authoritative one succeeds an event, indicating its
outcome as good or ill fortune. In the ordinary
case, people are busied neither with action nor design
when the lightning suddenly occurs. The flash
conveys either threat, promise, or warning. The
last form is indeed called admonitory : I am disposed
to think it is identical with the counselling mentioned
above. One who warns at the same time counsels.



xxxix DIFFERENT KINDS OF LIGHTNING 87

Yet there is a distinction between them. Therefore
they are put in different classes. The one applies
suasion or dissuasion, the other is restricted to
warning how to avoid an impending danger ; as, for 3
example, fire, or deception from neighbours, or a
plot by slaves. Besides, I can perceive another
difference between the two kinds : if one has a
design, then the lightning that occurs counsels ; but
if one has no such design, it warns. Each situation
has its own peculiar features. In deliberation advice
is appropriate, but a warning comes unsought.



XL

ON the face of it, one s comment on this view i
would be that these are so many kinds of prognosti
cations and not of lightning. Of the latter the
kinds are the boring, the splitting, and the scorching.
The first has a subtle flame, which from its un
alloyed purity can win escape through the tiniest
aperture. The second, which scatters to the winds
what it strikes, is massed fire with an admixture of
condensed tempestuous wind. So the first kind
escapes again by the opening by which it entered.
The second spreads wide the effects of its violence,
it bursts what it strikes, and does not perforate it.
The third kind mentioned, the scorching, has much 2
earthiness in its composition, and contains fire
rather than flame. It therefore leaves deep scars
of fire, which will be branded in what it has struck.
No lightning, it is true, that comes to earth is
fireless, but this kind is distinctively called fiery,
because it imprints the marks of fire so manifestly,
by either scorching or staining. It scorches in three



88 PHYSICAL SCIENCE BK. n

different ways, that is, it either breathes on its
object, so to speak, inflicting slight injury, or burns
it right up, or sets it on fire. All those are methods
of what I have called scorching, differing, however,
in character and degree. Whatever is, for example,
3 burnt up is necessarily scorched as well. But [the
converse is not equally true], everything that is
scorched is not necessarily burnt up. And so with
what is set on fire ; it is not necessarily consumed,
the fire may merely have scorched it in passing.
Everybody knows that things may be scorched
without breaking out into fire, but that nothing can
break out into fire without being scorched. I have
only one further remark on the point : an object
may be consumed without being set on fire ; it may
also be set on fire without being consumed.



XLI

1 I PASS on now to the kind of lightning that stains
objects struck by it. The staining is either dis
colouring or colouring, between which I draw a
distinction. When the colour is spoiled, without
being changed, there is discolouring. On the con
trary, there is colouring when the aspect of an object
becomes different in kind from what it was, for
example, when it turns dark blue or black or pale. So
far the Etruscans and the philosophers are in agree
ment. But disagreement begins when the former
go on to assert that lightning is sent by Jupiter, to

2 whom they assign three species of bolt. The first,
according to their statement, gives a peaceful
warning, being sent by Jove s own counsel. The
second is, it is true, sent also by him, but by advice



XLI ETRUSCAN BELIEFS 89

of his council, to which he summons the twelve
gods as assessors. This bolt is no doubt beneficial,
but not without doing damage to some extent. The
third kind of bolt is still of Jove s sending, but he
summons into council the so-called supreme veiled
gods. This bolt causes destruction of what it
encounters, and in particular it changes the existing
condition of private and public affairs that it finds
For fire allows nothing to remain as it is.



XLII

TAKING a superficial view one would pronounce i
these old beliefs all wrong. What could be more
absurd than to believe that Jupiter hurls bolts
from the clouds, aiming at pillars, trees, aye, and
statues of himself sometimes, or that, passing by
the sacrilegious unbelievers, he strikes sheep,
sets fire to altars, and smites innocent flocks ? or
can one imagine that great Jove should call the
gods into council, as if he were himself lacking
in counsel ? Or that those bolts bring promise of
peace and joy that he hurls unaided, and those
cause destruction in whose despatch a greater
crowd of deities was concerned? If you ask my 2
opinion on the point, however, I may tell you that
I do not for a moment suppose those people of old
were so obtuse as to believe that Jupiter was evilly
disposed or, to say the least of it, insufficiently
prepared with his missiles. When he issued fiery
bolts to pass over the heads of the wicked and
strike the innocent, as is alleged, did he, do you
suppose, refuse to send them with truer aim, or did
he miss his shot ? If that cannot be the explanation,



90 PHYSICAL SCIENCE BK. n

what was the idea of those ancients in speaking as
3 they did ? Being men of profound wisdom they
were, in my opinion, of the settled conviction that
fear was essential to restrain the passions of the
ignorant ; we must reverence something higher than
ourselves. In a time of such audacious crime it
was expedient that there be a belief in something
which no criminal could seem powerful enough to
resist. And so it was to terrify those wretches,
against whose passions innocence is no protection
unless backed up by fear, that they placed over us
in the heavens the image of an avenger, and him
well armed.

XLIII

WHY, therefore, on this assumption, is the bolt that
Jupiter sends alone, peaceful, while the other is
destructive on which he has sought counsel, and
which he has sent down with the approval of other
gods besides ? The reason is that Jupiter, that is,
an absolute monarch, when acting alone ought to
be always a power for good ; he should not inflict
injury unless when a numerous council has ratified
the decision. From this let all those who have
inherited great earthly power learn that not even
the bolt of heaven is sent without counsel taken.
Let them call to them their advisers, let them
ponder the opinions of a multitude of counsellors,
let them temper the rigour of their decrees ; and
when some blow must fall, let them not forget that
even Jupiter needs more than his own wisdom to
guide him.



XLIV JOVE S BOLTS 9*



XLIV

NOR, again, were the ancient sages so stupid as to i
suppose that Jupiter changed his missiles. It is
only the licence of poetry that can with decency
say :

There is another and lighter bolt to which the Cyclopes hands
Have added less of harshness and of flame, less, too, of wrath.
The dwellers above call them missiles of peace.

Those men of exalted wisdom were undoubtedly 2
not possessed with the delusion that Jupiter some
times employs lighter bolts, weapons of the
practising school, so to speak. Their object was
to warn those who have to direct their bolts against
the sins of men, that all offences are not to be
visited after the same fashion : some offenders must
be crushed, some censured and lightly punished,
some l dismissed with an admonition.



XLV

NOR yet did these ancient sages believe that the
Jupiter we worship in the Capitol and the rest of the
temples ever really hurled thunderbolts from his
hand. They recognised the same Jupiter as we do,
the guardian and ruler of the universe, its soul and
breath, the maker and lord of this earthly frame of
things, to whom every name of power is appro
priate. If you prefer to call him fate, you will not
be wrong. He it is on whom depend all things,

1 Admoneri to be admonished, seems necessary, instead of the
authorised admoveri^ to which it is impossible to attach any satisfactory
meaning in this connection. The word means to be moved towards ;
amoveri = to be removed, would make sense.



92 PHYSICAL SCIENCE BK. n

from whom proceed all causes of causes. If you
prefer to call him providence, you will still be right;
2 for he it is by whose counsel provision is made for
the world that it may pursue its orderly course and
unfold the drama of its being. If you prefer to call
him nature, you will make no mistake ; for it is he
from whom all things derive being, and by whose
breath we live. If you prefer to call him the
world, you will not be in error ; for he is everything
that you can see, he is wholly infused in all his
parts, self-sustained through inherent power. The
Etruscans thought so too. They said bolts were
sent by Jove, just because nothing is performed
except by his power.



XLVI

BUT, you ask, why does Jupiter pass over the guilty
and strike the innocent ? That is too big a question
to enter on here ; it shall have its own place and
time. Meantime I insist on this, that bolts are not
sent directly by Jupiter, but that all things are so
arranged that even what is not done by him is yet
not done without some plan, which plan is his.
The force of the bolts is a consequence of his per
mission. For even though Jupiter does not make
them, he caused them to be made. He does not
superintend every detail ; but to all he gives the
signal, force, and cause.

XLVII

THERE is another division of them made to which
I cannot agree. They are, according to the asser-



XLVII WRONG CLASSIFICATION 93

tion of some, either constant or limited or deferred.
The constant are those whose prognostication
extends all over life, not merely intimating a single
occurrence, but embracing the series of coming
events through the whole subsequent life. This is
the kind of bolt that occurs first after entrance on
an inheritance, or when an individual or a city has
entered on a new phase of existence. Limited ones
answer exactly to a definite date. Deferred are
those whose threats may be delayed, though they
cannot be averted and completely avoided.



XLVIII

I WILL now state my reasons for disagreeing with i
this division. One is that even the bolt which is
called constant lasts for a limited period. Such
bolts correspond no less than others to a definite
date. Nor do they cease to be limited because the
period they signify is a long one, So, too, what is
thought to be deferred is limited. For by the
admission of the advocates of this division the
period for which delay can be procured is a definite
one. Bolts that relate to private matters cannot,
according to them, be delayed longer than ten
years, those relating to public affairs not more than
thirty. So this class, as well as the first, is limited,
as it includes the date beyond which the prognosti
cation cannot be deferred. There is thus a fixed 2
period for bolts and results of every kind. For of
what is uncertain there could be no distinct know
ledge. Then, too, these people talk in too vague
and general terms about the points to be noted
in lightning. They ought rather to divide them



94 PHYSICAL SCIENCE BK. n

according to the scheme of the philosopher Attalus,
who had specialised in this department. The
inspection should determine where the lightning
occurred, when, to whom, in what connection, of
what kind, of what amount. If I were to attempt
to arrange and classify all these, I should just be
committing myself to an endless task.



XLIX

1 LET me now glance at the names of the lightning
adopted by Caecina, and explain my own opinion
of them. He calls one kind imperative, as it de
mands the re-establishment of sacrifices neglected or
informally offered. Admonitory is the second kind,
giving information of what must be guarded against.
Pestilential is a kind that portends death or exile.
Deceptive is that which, under guise of some

2 benefit, inflicts injury ; for example, it gives the
consulship to some one whose ruin the office will
prove, or bestows an estate the profit of which must
be compensated by some great loss. The avertible,
again, bring an appearance of danger without real
danger. The destructive remove the threats
of previous lightning. The attested signify an
agreement with former lightning. The earth-borne
occur in a covered place. The overwhelming
strike what was previously struck without due

3 atonement having been made. The royal smite
either the election ground or the government quarter
of a free city ; their prognostication threatens a
free state with an absolute monarchy. Infernal
are when fire issues from the ground. Hospitable
summon or, to use a more polite word, invite



XLIX CAECINAS AND ATTALUS DIVISIONS 95

Jupiter to share a sacrificial feast with us. If he
happen to be angry with his host when he is
invited, then his coming, Caecina says, is fraught
with danger to his entertainers. Auxiliary come by
summons too, but bring good to the summoner.



BUT how much simpler is the division employed i
by our distinguished Stoic, Attalus, who combined
skill in the Etruscan lore with all the subtlety of
Greek thought ! Of the different kinds of lightning,
he says, one gives intimation of something that
concerns us, another kind intimates either a thing
of no importance or something whose meaning
does not reach us. Of the significant lightning
there are several varieties one is favourable, one
unfavourable, a third neither one nor other. Of 2
the unfavourable there are all these forms the evils
portended may be either unavoidable or avoidable,
or such as may be mitigated, or such as may
be delayed. Again, the benefits foretold by the
favourable may be either abiding or transient.
The mixture of favourable and unfavourable
may either consist of half and half, good and
ill ; or ill may be turned by them into good, or
good into ill. The lightning that is neither un
favourable nor favourable gives us intimation of
some action by which we need neither be terrified
nor elated, for example, a journey abroad from
which there is nothing either to fear or hope.

LI

LET me revert for a moment to the lightning that
portends something, but a something that does not



96 PHYSICAL SCIENCE BK. n

concern us ; for instance, whether the same kind of
lightning as has occurred will again occur in the
same year. Sometimes lightning contains no indi
cation at all, or one whose grasp eludes us ; as, for
example, those manifestations of it that are scattered
through the spaces of the sea or in lonely deserts.
Their indication, if any, is lost.



LII

1 I HAVE still a few remarks to add in order to show
more fully the force of lightning in various ways,
for its power is not always displayed in just the
same way in every kind of material. For instance,
the stronger bodies are shattered with greater
violence on account of their resistance ; it some
times passes through the yielding ones without
doing any damage. With stone and iron and all
the hard substances it enters into conflict, because
in its impetuous course it must find a way through
them ; so it makes a way by which to escape. The
more flexible and thinner substances, though they
seem very suitable material for flames, it spares,
mitigating its fury when it encounters no obstacle
to its passage. And so, as I said at a previous
point, coin is found fused, while the purse that
contained it is untouched ; the extremely thin fire
runs through the invisible interstices of the latter.
But whatever solidity it meets in a beam it subdues

2 as being refractory. For, as I have just said, its
fury does not always take the same form ; the
nature of the force in each case is revealed merely
by the kind of the damage, and you can tell the
species of the lightning by its effect. Again, the



LII LIGHTNING IRRESISTIBLE 97

force of the same flash produces many varieties of
damage in the same material. For example, in a
tree it scorches any portion that is very dry ; what
is firm and hard it bores through and smashes ; the
outer bark it scatters, the inner layers nearer the
centre it bursts and cuts up, the leaves it lashes and
strips off. Wine is frozen, iron and copper fused.



LIII

IT is a strange fact that when wine that has been i
thus frozen is used after it returns to its liquid state, it
either kills or drives mad those who have drunk of it.
When one inquires why this effect should be pro
duced, the suggestion presents itself that the
lightning contains a pestilential force, some taint
of which probably is left in the liquid it has con
densed and frozen. Indeed, the substance could
never have been solidified had not some bond of
cohesion been introduced. Moreover, in oil and
every kind of unguent there is a foul smell after
lightning has touched them. Whence it is manifest 2
that this subtle fire, driven in a direction contrary
to its nature, contains a pestilential power, for not
only its blow but even its mere breath is over
whelming. Moreover, wherever lightning has
struck there is sure always to be a smell of sulphur,
a substance which, being naturally poisonous, causes
delirium if breathed too freely. But we shall
return to this point when we are more at leisure.
For I should like some day to prove the extent to
which the world is indebted to philosophy, the
parent of the arts, for knowledge of all such
matters. She it was that first both investigated the

H



98 PHYSICAL SCIENCE BK. n

causes of things and noted their effects. She per
formed a service far more valuable than the
inspection of lightning in thus comparing results
with the principles from which they are derived.



LIV

1 I WILL at this point revert to Posidonius opinion
of the cause of thunder. From the earth and its
confines are exhaled certain elements, partly moist,
partly dry and smoke-like. The latter element
remains in the sky as material for lightning, while
the former falls in rain. The dry smoky particles
that reach the atmosphere will not allow themselves
to be enclosed in clouds, but burst their envelope.
Thence comes the report which we name thunder.
Besides this, anything in the atmosphere itself that
is rarefied is at the same time dried and heated up.

2 This also, if it is enclosed, seeks an exit with equal
eagerness, and causes a report as it escapes. On
one occasion it makes a complete burst, and the
thunder is consequently the more violent ; on
another it escapes by degrees in small portions.
Air of this kind, then, by either bursting or flying
through the clouds, produces peals of thunder. The
rolling of the air enclosed in a cloud is the most
potent cause of setting fire to what is struck.



LV

i THUNDER is, in short, simply the report of ex
plosions of dry air, which cannot occur unless there
is either friction or a rent in a cloud. Posidonius



LV CA USE OF THUNDER 99

adds that if the clouds merely collide with each
other, the kind of blow needed to produce an
explosion is given, but not completely ; clouds do
not meet through their whole extent, but only part
with part. And again, soft substances do not
resound unless knocked against hard ones ; a wave
is not heard unless when it beats on the hard shore.
But fire, which is soft, says an opponent, when let
into water, also a soft substance, produces sound in
being extinguished. Well, suppose it is so, it makes 2
for the opposite view which I urge. For it is not
really the fire that makes the sound, but the air
escaping through the water that is quenching it.
Granted that fire is both produced and extinguished
in the cloud, it arises from air and friction. Well
then, it is urged, may not some of the shooting
stars plunge into a cloud and be extinguished ?
Even supposing that such a thing can and some
times does occur, it does not remove the difficulty.
It is not the occasional chance cause but the natural
normal one that we are in search of. Suppose I
admit the truth of your contention that occasionally
after thunder fires gleam in the heavens much like
shooting and falling stars. Yet this does not prove 3
that the thunder was caused by them ; it merely
shows that the thunder occurred simultaneously
with this other phenomenon. Clidemus asserts that
a lightning flash is an empty reflection, and not real
fire ; for in the same way after nightfall a gleam
appears from the motion of oars in water. His
illustration is not on all fours with the phenomenon.
In the latter case the gleam is seen actually within
the water ; in the former, in the atmosphere, it
bursts and leaps out of its element.



TOO PHYSICAL SCIENCE BK. n



LVI

HERACLITUS is of opinion that the flash of lightning
is the first attempt of a fire to kindle ; just as on
earth when the flame is at first unsteady, now
dying down and now darting up again. The
ancients used to call this summer lightning.
We now say in the plural thunder peals (toni-
trua) ; the ancients said either thunder (tonitruum,
sing.) or merely peal (noise, tonus). The fore
going remark I find in Caecina, an eloquent man, who
would have had a considerable reputation as such
had he not been overshadowed by Cicero s towering-
form. Besides, the ancients had other variants of
a similar kind. They employed with the penult
short the word that we use with it long ; we say
fulgere (to lighten) just as we do splendere (to
gleam). But in order to denote this sudden burst
of light from the clouds their usage was to shorten
the middle syllable so as to make it fulgere.



LVII

WHAT do I think myself about the matter, you ask.
For up to this point I have been reproducing the
opinions of others. Well, I will tell you. There
is lightning when light bursts out suddenly and
widely. This occurs when the atmosphere has
been changed, by the rarefaction of the clouds, into
fire, which has not gathered strength to issue to
any considerable distance. There is, I presume, no
cause for surprise either that movement rarefies
air or that rarefaction kindles fire. In the same



LVII RAREFACTION AND FRICTION 101

way a leaden bullet is liquefied when discharged
from a sling, and falls in drops by reason of
atmospheric friction just as it would do through
fire. Bolts of lightning are more numerous in 2
summer, for the reason that there is most heat at
that season. Fire naturally starts more readily
when the friction is in warmer air. A flash of
lightning which merely gleams and a bolt which is
discharged are produced in exactly the same way.
But there is less force in the former case and less
fuel. To put my opinion on the point shortly : a
bolt is just lightning in its most intense form. So 3
then, when a body of the nature of heat or smoke
is exhaled from the earth and, meeting with clouds,
is for a long time rolled about in their hollows, at
last it bursts out. Since it possesses no strength, it
is merely a flash. But when lightnings have more
material and burn with fiercer glow, they not merely
become visible, but also fall to the earth.



LVIII

SOME writers are firmly convinced that the lightning
bolt always returns to the clouds. Others hold that
the bolt settles in the ground, at least when its fuel
is heavy, and when it has comparatively little force
in its stroke as it glides down. But why, it may be
asked, does the bolt make its appearance suddenly,
and is there not a continuous trail of fire ? It is on
account of the extreme rapidity of its motion ; it
fires the air at the same moment as it bursts
through the cloud. By and by when the motion
ceases, the flame subsides. For the course of the
air that forms the bolt is intermittent, which pre-



102 PHYSICAL SCIENCE BK. n

vents continuity in the fire. As often as the air
by its more violent agitation sets itself on fire it
conceives an impulse toward flight. When the
internal conflict has been ended by its escape, it is
afterwards for the same reason sometimes carried
down as far as the earth, and sometimes, if urged
down with less force, it is dissipated in air. Why,
again, is the course of the lightning oblique ? The
reason is that the air current of which it is composed
3 is oblique and tortuous. Nature summons fire up
ward, violence presses it downward, and so it begins
to be zigzag. Sometimes, when neither force gives
way to the other, the fire is at the same moment
urged toward the upper and depressed toward the
nether regions. Why are the peaks of mountains
frequently struck by it ? Because they are exposed
to the clouds, and objects falling from heaven to earth
must pass by way of them.

LIX

1 I KNOW quite well what you have long been anxious
to say and what you demand. I had rather, you
say, get rid of fear of thunderbolts than learn all
about them. So you may reserve for others your
instruction regarding their origin. Let me be
delivered from fear of them rather than be informed
of their nature. Well, I will follow your invitation,
for I quite allow that some moral should be attached

2 to all studies and all discourse. As we dive into
the secrets of nature and treat of things in the
heavens, the soul must be delivered from its errors
and from time to time reassured. Even the learned
who devote themselves exclusively to this pursuit
require such reassurance ; not in order to escape



LIX THE MORAL 103

the arrows of fortune, for her missiles are hurled
on us from every side, but in order to bear them
with resolution and constancy. Unvanquished we
may be, unassailed we cannot be, though meantime
the hope sometimes insinuates itself that even this is
possible. How ? you exclaim. Despise death and 3
then everything that leads to death is despised, be
it war or shipwreck, or the jaws of wild beasts,
or the weight of roofs rushing down with sudden
fall. What more can they do than part the body
from the soul ? And this parting no care can
shun, no good fortune can remove, no power can
prevent. Other features in human lot are variously 4
assigned ; to death s call all are alike subject.
Whether heaven is propitious or wrathful, die we
must.

Let courage be derived from our very despair.
The most cowardly of animals which nature has
created for flight, if they find no way of escape
open to them, show fight with their unwarlike
body. In fact, no foe is more deadly than one into
whom a tight corner has put courage. Far more
violent resistance is offered to death through
necessity than through valour. A desperate soul 5
shows as much daring as a courageous, probably
more. Let us assume that, so far as concerns death,
we are given over to it ; and so we are. The fact
is so, Lucilius ; we are all destined to death. All
this nation that you see, all the people you can
anywhere suppose to exist, will some day soon
be recalled by nature to the grave. There is no
question of the fact, only of the day. Sooner or
later we must all go to the one place. Well, then, 6
does not he seem to you the most fearful and silliest
of men who by great entreaty seeks to delay death ?



io 4 PHYSICAL SCIENCE BK. u

Would you not despise a man who was set in a
company of those appointed to death if he asked
by way of favour to be allowed to be the last to
lay his head upon the block ? We do the same
in setting such store upon a little delay in the time
of death. Capital punishment is the sentence on

7 all mankind, and the sentence is most just. We
possess what is wont to be regarded as the greatest
consolation that those sentenced to the extreme
penalty could enjoy ; the circumstances of all being
the same, our fate is the same. If handed over by
a judge or magistrate to execution, we should follow
and render obedience to our executioner ; what
difference does it make whether it is by order of
another or of our own accord that we go to death ?

How foolish you must be, how forgetful of your
feebleness if you are afraid of death every time it
thunders ! Does your abiding safety really depend

8 on this ? Will life be secure if you escape the
lightning ? You will be a victim of the sword,
of a stone, of a fever. The lightning is not the
most serious of dangers, it is only the most con
spicuous. Your fate, I should think, would not be a
bad one if the inconceivable rapidity of your death
prevented any sense of it, if your death was the
occasion of sacrificial ceremonies, if even when you
breathe your last, you are not quite a superfluity,

9 but remain as a sign of some great event. Your
fate is surely not bad if you are buried along
with the bolt of lightning. And yet you are in
panic at a crash in the sky, you tremble at the
sound of a hollow cloud ; as often as there is a
flash you are ready to give up the ghost. Well
then, is it in your judgment more creditable to die
of sheer chicken-heartedness than to be killed by



LIX CALMNESS AND COURAGE 105

lightning ? Rather, say I, confront all the more
resolutely the threats of the heavens, and when the
universal world is in flames around you, consider
that in such a mighty mass you have nothing to
lose. But if you can bring yourself to believe that 10
that wreck of heaven, that conflict of the stormy
winds, is aimed at you, if it is on your account
that the clouds are piled up and collide and roar, if
it is for your destruction that such a mass of fire is
scattered abroad, then you may surely regard it as
some consolation that your death has cost so dear !
But there will then be no room for such a reflection.
The fate of one struck by lightning removes all
fear. Among other advantages it includes this, that
it anticipates your expectation ; no man ever was
afraid of lightning except one who had escaped it.