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BOOK VI, tr. John Clarke

BOOK VI

WHICH TREATS OF EARTHQUAKES



219



WE have just had news, my esteemed Lucilius, i
that Pompeii, the celebrated city in Campania, has
been overwhelmed in an earthquake, which shook
all the surrounding districts as well. The city, you
know, lies on a beautiful bay, running far back from
the open sea, and is surrounded by two converging
shores, on the one side that of Surrentum and
Stabiae, on the other that of Herculaneum. The
disaster happened in winter, a period for which our
forefathers used to claim immunity from such
dangers. On the 5th of February, in the consulship 2
of Regulus and Virginius, this shock occurred,
involving widespread destruction over the whole
province of Campania ; the district had never
been without risk of such a calamity, but had been
hitherto exempt from it, having escaped time after
time from groundless alarm.

The extent of the disaster may be gathered
from a few details. Part of the town of Hercu
laneum fell ; the buildings left standing are very
insecure. The colony of Nuceria had painful ex
perience of the shock, but sustained no damage.
Naples was just touched by what might have proved
a great disaster to it ; many private houses suffered,
but no public building was destroyed. The villas 3
built on the cliffs everywhere shook, but without

221



222 PHYSICAL SCIENCE BK. vi

damage being done. In addition, they say, a flock
of six hundred sheep was destroyed, and statues
were split open ; some people were driven out of
their minds, and wandered about in helpless idiotcy.
The plan of my present work demands a discussion
of the causes of this, and the disaster itself fits in with
our present inquiries (i.e. our discussion is opportune
in view of the recent disaster). We must seek solace
for the anxious and dispel overmastering fear. For
what can any one believe quite safe if the world
itself is shaken, and its most solid parts totter to

4 their fall ? Where, indeed, can our fears have limit
if the one thing immovably fixed, which upholds all
other things in dependence on it, begins to rock,
and the earth lose its chief characteristic, stability ?
What refuge can our weak bodies find ? whither
shall anxious ones flee when fear springs from the
ground and is drawn up from earth s foundations ?
If roofs at any time begin to crack and premonitions
of fall are given, there is general panic : all hurry
pell-mell out of doors, they abandon their household
treasures, and trust for safety to the public street.

5 But if the earth itself stir up destruction, what
refuge or help can we look for ? If this solid globe,
which upholds and defends us, upon which our
cities are built, which has been called by some the
world s foundation, stagger and remove, whither
are we to turn ? What comfort, not to say help,
can you gain when fear has destroyed all way of
escape ? Where, I say, is there any protection you
can trust? what is there that will stand as sure
defence either of oneself or of others ? An enemy
I can drive off from my city wall. The mere
difficulties of approach to turrets set on the dizzy
heights will stop the march even of great armies.



i WHOLESALE DESTRUCTION 223

From storm the harbour shelters us ; our roofs are 6
able to withstand the whole force of clouds let loose,
and the endless deluges of rain. Fire cannot pur
sue us if we run away from it. Against heaven s
threats in thunder refuges underground and caverns
dug out in the depths of the earth are of avail
the fire of heaven does not pierce the ground,
but is beaten back by the tiniest portion of the
soil. In time of plague we may change our place
of abode. No species of disaster is without some
means of escape. Lightning has never consumed
whole nations. A plague-laden sky has drained
cities, but has never blotted them out.

But this calamity of earthquake extends beyond 7
all bounds, inevitable, insatiable, the destruction of a
whole State. Nor is it only families or households
or single cities that it swallows ; it overthrows
whole nations and regions. At one time it hides
them in their ruins, at another consigns them to the
deep abyss ; it leaves not a wrack behind to witness
that what no longer is, once was. The bare soil
stretches over the site of the most famous cities,
and no trace is left of their former existence.
Nor are there wanting those who dread most of
all this kind of death, in which they go down alive
into the pit, houses and all, and are carried off
from the number of the living : as if every form
of death did not lead to the one goal. Among g
nature s righteous decrees this is the chief, that
when we reach the end of life we are all on a level.
It makes no difference, therefore, to me whether
one stone wound me to death or I am crushed
beneath a whole mountain ; whether the weight of
one house come down on me, and I expire beneath
the dust of its humble mound, or whether the whole



224 PHYSICAL SCIENCE BK. vi

world descend upon my head; whether I yield up this
breath in the open light of day or in the vast abyss
of the yawning earth ; whether I am borne down
to those depths all alone or along with a great
9 throng of perishing nations. To me it can make no
difference how great is the turmoil that accompanies
my death ; the thing is everywhere just the same.

Wherefore, let us raise high our courage against
that disaster, which can neither be shunned nor
yet foreseen. Let us cease to listen to the people
that have bid adieu to Campania since the time
of this disaster, and have removed to other dis
tricts, vowing they will never set foot in that
quarter again ! Who can guarantee them more

10 solid foundations in whatever soil they choose ? All
the world is subject to the same fate. If it has not
yet suffered from earthquake, it may ; perchance
this spot on which you stand in full security will be
rent this night, or even this day before night. How
can one tell whether is better the state of the places
on which fortune has already spent her force or of
those which are upheld meantime, but only for
some disaster to come ? We do greatly err if we
suppose any quarter of the world wholly exempt
from this danger. All quarters are subject to the
same law. Nature framed nothing to be immovable.

11 Different things will fall at different times. Just as in
large cities, now this house and now that leans over
and has to be shored up, so in the world as a
whole, now this part contains a flaw, now that.
Tyre was once notorious for a disaster of the kind.
The province of Asia lost at a single stroke twelve
of its cities. Last year calamity overtook Achaia
and Macedonia, now the injury has fallen upon
Campania, whatever be the nature of that force



i EARTHQUAKES UNIVERSAL 225

which thus assails us. Fate makes a circuit, paying
a second visit to places she has long passed over.
On some places her attacks are more rare, more 12
frequent on some. Nothing is suffered to be quite
exempt from injury. Not merely we men, whose
life is frail and fleeting, but cities too, and the earth s
coasts and shores, yea, the very sea falls under
bondage to fate. And in face of this we promise
ourselves permanence in the boons fortune bestows !
we suppose there will be stability and endurance in
happiness, whose fickleness is greatest of all things
on earth ! While men promise themselves all things 13
in perpetuity, it never enters their thoughts that the
very earth on which we stand is not permanent. The
flaws of the ground are to be found everywhere ;
they are not peculiar to Campania or Tyre or
Achaia. The earth coheres imperfectly, it suffers
breach from many causes ; permanent as a whole,
it is subject to collapse in its parts.



II

WHAT am I doing ? I had promised to offer
comfort in face of danger, and lo ! I threaten its
terrors on all sides. I tell you that there can
be no assured peace in what can suffer or cause
destruction. But that very fact I regard as a solace,
and, indeed, the most powerful of all. Fear is but
folly when there is no escape from it. Philosophy
delivers the wise from fear ; even the unlearned
may derive great confidence from despair. You
must, therefore, regard the words addressed to those
amazed by sudden captivity amid fire and foe as
addressed to the whole human race :

The one safety of the conquered is to hope for none.

Q



226 PHYSICAL SCIENCE UK. vi

2 If you wish to fear nothing, think that every
thing is to be feared ; consider by how slight
causes our life is dissipated. Neither food nor
drink, nor waking nor sleeping, is healthful, except
in due measure. One may soon realise that
we are but puny, insignificant bodies, weak and
unstable, that small effort is needed to compass our
destruction. The only sufficiency of danger, doubt
less, would be the earth s trembling, its sudden
dissipation, the rending of its surface into chasms !

3 Surely he sets a high value on his life who dreads
only lightning, and earthquakes with their yawning
abysses ; won t he allow himself to open his eyes to
his frailty and be afraid of choking on his phlegm ?
Such, forsooth, is our constitution by birth, such
the powerful frames we have obtained, such the
size we have grown to, that we cannot perish unless
the four quarters of the world are moved, the

4 heavens thunder, and the earth subside ! Why, a
pain in a tiny nail, not even the whole nail, but a
little ragnail at the side, may finish us ! And I must
fear only the trembling of the world, when too
thick a spittle will choke me ! I am to await with
dread the removal of the sea from its place, or the
overflowing of an abnormal tide with its excess of
water ; why, some ere now have been strangled by
a drink that took a wrong course down the throat !
What folly to be afraid of the sea when you know

5 that a single drop may kill you ! There is no
solace of death greater than the very liability to
death, no solace of all the terrors from without equal
to the thought that there are countless dangers
within our own bosom. What greater madness than
to collapse at the sound of thunder, and through
fear of lightning to creep under the ground ? What



ii DEATH UNIVERSAL 227

greater folly than to stand in fear of the earth s 6
tottering and the sudden fall of mountains, or inroads
of the sea cast up beyond the shore, when death
is everywhere present and meets us on every side ?
Nothing is so small as not to be strong enough
to compass the destruction of the human race.
Great or unusual dangers ought not to unnerve us,
as if they implied more mischief than a common
death ; nay, rather when one must quit the world
and at last resign life, it should be a positive joy to
perish by some grand cause. Die we must some- 7
where, sometime. The ground you tread may stand
firm, it may confine itself within its own bounds and
not be tossed about by any violence ; yet some day
I shall be beneath it. Does it really matter, then,
whether I place it on myself or itself do ? It is rent
by the irresistible force of some disaster ; it bursts
and draws me into its immense depths. What
then ? Is death easier on the earth s level surface ?
What reason for complaint have I if nature will not
have me lie in a place unknown to fame ? or if she
lays on me a portion of herself? My friend, 8
Vagellius, 1 in that famous poem of his, says finely:

If fall I must, I should desire to fall from the height of heaven, 2

We may adopt the language. If fall I must, let the
earth be shaken at my fall ; not that one ought to
pray for a public disaster, but it is a great solace
of death to see that the earth is likewise subject to
death.

1 The name is doubtful, as is, indeed, the quotation also.

2 The sense may be : I would have the heavens fall along with me ; this
meaning would suit the context better.



228 PHYSICAL SCIENCE BK. vi



III

1 IT will be useful also to be assured that none of
these things is the doing of the gods, and that the
moving of heaven or earth is no work of angry
deities. Those phenomena have causes of their
own. It is not by special command that they put
forth their rage, but, just as in our own bodies, the
disturbance arises from certain inherent imper
fections ; at the moment when they seem to inflict
injury, they sustain it. Through our ignorance of
the truth all these things are terrible, the more as

2 their infrequency increases our alarm. Familiar
occurrences seem less serious ; the unusual causes
greater terror. But why is anything unusual in our
estimation ? The reason is that we grasp the
meaning of nature only superficially, and not
rationally ; we dwell too exclusively on what she
has done, and do not consider what she can do.
Accordingly, we pay the penalty of this neglect in
our terror of things that we suppose unprecedented,
when they are not really unprecedented, but merely
unusual. For instance, are not superstitious fears
inspired both privately and even for the safety of
the State, if either the sun has been seen in eclipse
or if the moon, whose obscuration is more frequent,

3 has partially or wholly been concealed ? And is
not this far more so in the case of such sights
as we have spoken of: torches driven athwart
the heavens, the sky on fire over the greater part
of its extent, comets, mock suns, stars appearing
in the daytime, the sudden passage of stars that
mark their trail with a bright light ? Our wonder



in EARTHQUAKES HAVE NATURAL CAUSES 229

at these is in no case free from fear. As the
cause of the fear is ignorance, is it not worth while
to gain the knowledge that will dispel it ? How
much better it would be to inquire into the causes
of the alarming sights, to bend, in fact, our whole
mind to the task ? Nothing, surely, could be found
more deserving than that, of having the mind s
energies not only lent to it, but devoted to it.



IV

LET us ask ourselves, therefore, what it is that stirs i
the earth to its foundation, what moves a mass of
such weight, what it is that is stronger than the
earth, and that in its violence can shake such a
load. Let us inquire why at one time the earth
trembles, at another is loosened and sinks, and
again is divided into parts and opens a chasm ;
or why on some occasions the intervals of destruction
are prolonged, on others are suddenly cut short.
What is the cause why it now consigns to its
depths rivers of renowned greatness, and now causes
fresh rivers to issue ? why does it sometimes open
up springs of hot water, sometimes freeze them 2
with cold ? and why at times are fires caused to
shoot out through some hitherto unknown opening
in mountain or crag, while sometimes well-known
fires, that have been famous for centuries, are sup
pressed ? The earthquake produces a thousand
strange sights, changing the aspect of the ground,
levelling mountains, elevating plains, exalting
valleys, raising new islands in the deep. What are
the causes that bring these things to pass ? That
is a subject well worthy our discussion. What, you



2 3 o PHYSICAL SCIENCE BK. vi

say, will be the reward of our labour ? That
reward, I say, which surpasses all others, the
3 knowledge of nature. Among the many serviceable
lessons to be derived from such researches, no
feature is more commendable than this, that man is
thereby made to dwell upon the sight of his own
grandeur 1 ; the study is pursued, not in hope of gain,
but from the wonder it excites. Let us inquire, there
fore, what it is that brings about all this. The
inquiry is so fascinating to me that although long
ago in my youth I published a volume on earth
quakes, I am anxious to make another trial of my
powers, and to see whether age has added anything
to my knowledge, or, at any rate, to my industry.



1 THE cause of earthquakes has been assigned
variously by different authorities to water, fire, air,
and to the earth itself ; some assign it to a combina
tion of several of the causes, others, to a union of them
all. Certain writers have stated that it was plain
to them that some one of these causes produced the
earthquake, but it was not plain which. Let us
look at the various opinions in detail. First of
all, I feel bound to say in general terms that the
old views are crude and inexact. As yet men
were groping their way round truth. Everything
was new to those who made the first attempt to
grasp it ; only later were the subjects accurately
investigated. But all subsequent discoveries must
nonetheless be set down to the credit of those early

2 thinkers. It was a task demanding great courage

1 The meaning may rather be the grandeur of the subject.



v SCIENTIFIC DISCOVERY GRADUAL 231

to remove the veil that hid nature, and, not satisfied
with a superficial view, to look beneath the surface
and dive into the secrets of the gods. A great con
tribution to discovery was made by the man who
first conceived the hope of its possibility. We
must, therefore, listen indulgently to the ancients.
No subject is perfected while it is but beginning.
The truth holds not merely of the subject we are
dealing with, the greatest and most complicated of
all, in which, however much may be accomplished,
every succeeding age will still find something fresh
to accomplish. It holds alike in every other
concern ; the first principles have always been a
long way off from the completed science.



VI

WATER is the first cause alleged: more authors than i
one adopt this view, but it is not stated by all in
the same terms. Thales of Miletus is convinced
that the whole earth floats, and is upborne by mois
ture lying beneath it, which you may call either Ocean
or the great sea, or still mere elemental water of a
different character from the sea, the simple ingredient,
moisture. In these waves, in his opinion, the globe
is supported like some huge lumbering vessel in the
water which bears it. It is unnecessary for me to 2
reproduce his reasons for supposing that the heaviest
part of the world cannot be sustained in such a rare
and nimble element as air : for the earth s position
is not the question here but its movement. By way
of argument, to prove that water is the cause, he
adduces the fact that in every considerable earth
quake, as a rule, new springs burst out. So if



232 PHYSICAL SCIENCE BK. vi

a boat leans over to one side away from the straight,
the result is that it ships water. And, generally
speaking, in the case of all objects which water
supports, if they are unduly sunk, the water either
pours over them or at any rate rises to right and
left above its ordinary height.

3 Now, no lengthened consideration is needed
to prove the falsity of this view. Why, if the
earth were supported by water, and from time
to time shaken by it, it would be in perpetual
shock ; the wonder would be not that it was
tossed about sometimes, but that it was ever at
rest. Then, again, it would be shaken all over and
not at a single point : we never find only half the
ship tossed by the waves. But, according to present
experience, a shock never occurs over the whole
earth simultaneously, but is always felt at some
particular spot. How, then, can it be that what is
carried as a whole is not shaken as a whole, if the
shock comes from the body by which it is carried ?

4 But, it may be urged, why do waters burst out at
the time of earthquakes ? Well, in the first place,
there has often been earthquake without any fresh
supply of water appearing. Secondly, if the sup
posed cause of the water rushing forth were the
true one, it would pour all round the sides of the
earth, as we see happening under similar circum
stances in sea and rivers : when boats sink, the
increase of water shows itself chiefly over the sides.
Finally, the outburst of waters which Thales de
scribes would not be so small as he says, nor would
it ooze in like bilge-water through a chink, but from
the exhaustless reservoir that upbears all creation,
a mighty deluge would ensue.



vii WATER AS CAUSE OF EARTHQUAKE 233



VII

SOME, who, like Thales, attribute earthquake to the i
effects of water, give a different explanation of its
operation. There are, they say, many kinds of
waters running over the whole earth. In one
place there are constant rivers whose size renders
them fit for navigation, even without the aid of
rains. There is the Nile, rolling down its huge
volume all summer long : here are the Danube and
the Rhine separating with their streams the peaceful
from the hostile, the former checking attacks from
the Sarmatians and forming the boundary between
Europe and Asia, the latter keeping back the
Germans, a nation ever keen for war. Then there 2
are lakes of very wide extent, great pools surrounded
by tribes mutually ignorant of each other, marshes
that no boat can struggle through, that cannot be
passed even by the people that dwell on their
borders. Add, then, the multitude of fountains, and
of river sources that belch out of their recesses full-
grown streams. Besides, there are many rushing
torrents that gather only for a time, whose force is
as shortlived as it is sudden. Now there are waters,
in all this variety of form and character, within as 3
well as above the earth. Away there below some are
borne along in vast bulk, and tumble their whole
volume down the steep : others more sluggish are
dammed back in shallows, and flow with gentle, quiet
stream. And can any one deny that within those
vast underground hollows waters are formed, and lie
sluggish and inactive in many places? It needs no
long proof to show that there must be many waters



234 PHYSICAL SCIENCE BK. vi

in the place where all waters are. The earth would
not be able to produce so many rivers unless it
poured them from a copious reserve.

4 This being so, sometimes below the earth a
river must become swollen, and leaving its banks
assail with violence all obstacles that meet it. So
there will be a movement of some point on which
the river has made an onset, and which it will keep
lashing until its waters fall. Or it may happen that
the constant wear of a stream may eat away
some quarter, dragging down thereby some mass
above, by whose fall, in turn, the surface which

5 rested on it is shaken. Now surely a man trusts
too much to the sight of the eyes and cannot launch
out his imagination beyond, if he does not believe
that the depths of earth contain a vast sea with
winding shores. I see nothing to prevent or oppose
the existence of a beach down there in the ob
scurity, or a sea finding its way through the hidden
entrances to its appointed place. There, too, it
occupies as much space as here, perhaps more,
since the regions up on earth have had to be shared
with so many living creatures ; but the hidden
regions being desert without inhabitant give freer

6 scope to the waves of the nether ocean. And who
is there to hinder the sea from swelling there and
being tossed by all the winds that every interstice
of the earth, and every species of atmosphere can
create ? So, then, when a storm greater than ordi
nary has arisen, it may beat upon some one side of
the earth with too great vehemence and move it.
For on the surface likewise, many places which
had been far from the sea have felt the violence of
its sudden approach : villas almost out of sight of
it have been invaded by the waves which used only



vii ABUNDANCE OF UNDERGROUND WATER 235

to be heard in the distance. The nether sea, too,
can approach and retire ; neither of which movements
can take place without shock to the earth that stands
above it.



VIII

I DO not, indeed, suppose that you will long hesitate i
to believe that there are underground rivers and
a hidden sea. From what other cause could the
rivers burst out and come to the surface unless the
source of the moisture were shut up within the
earth ? For instance, when one sees the Tigris
interrupted and dried up in the middle of its course,
not diverted as a whole, but gradually with imper
ceptible, losses first lessen and then waste away,
where do you suppose it goes to if not to the depths
of the earth, especially as you see it emerge again
not less in volume than its former stream ? And 2
what are you to say when you see the Alpheus, so
celebrated by the poets, sink in Achaia and, having
crossed beneath the sea, pour forth in Sicily the
pleasant fountain Arethuse ? And don t you know
that among the explanations given of the occurrence
of the inundation of the Nile in summer, one is
that it bursts forth from the ground, and is swollen
not by rain from above but by water given out
from within the earth ?

I have myself heard from their own lips the 3
story told by the two non-commissioned officers
sent to investigate the sources of the Nile by our
good Emperor Nero, a monarch devoted to virtue
in every form, but especially solicitous for the
interests of truth. The King of Ethiopia had
supplied them with assistance and furnished letters



236 PHYSICAL SCIENCE BK. vi

of introduction to the neighbouring kings, and
so they had penetrated into the heart of Africa

4 and accomplished a long journey. "We came
indeed," I give their own words, "to huge marshes,
the limit of which even the natives did not know,
and no one else could hope to know ; so completely
was the river entangled with vegetable growth, 1 so
impassable the waters by foot, or even by boat, since
the muddy overgrown marsh would bear only a
small boat containing one person. There," my in
formants went on, " we saw with our eyes two rocks
from which an immense quantity of water issued."

5 Now whether that is the real source or only an
addition to the river; whether it rises there or
merely returns to the surface after its previous
course underground ; don t you think that, whatever
it is, that water comes up from a great lake in the
earth ? The earth must contain moisture scattered
in numerous places and collected at depth in order
to be able to belch it out with such violence.



IX

1 FIRE is the cause assigned by some for earthquakes,
but they are not agreed as to its method of action.
First among them is Anaxagoras, who is of opinion
that pretty much the same cause produces concus
sion in the earth as in the atmosphere. In the nether
parts of earth, air (gas) causes explosions of thick
atmosphere massed in clouds with the same violence
as on earth clouds are wont to be burst. Fire is
struck out by this collision of clouds and by the

2 rush of the atmosphere that is forced out. This fire

1 The so-called "sudd."



ix FIRE AS CAUSE 237

in seeking an exit meets obstructions and bursts
through all obstacles, until it has either found a way
of escape to the light through the narrow passages,
or has made one for itself by violence and destruc
tion. Other writers who still believe the cause to lie
in fire do not suppose that this is its method of
action : they think the fire presents itself in more
than one place and burns away everything in the
vicinity. Then if the parts eaten away fall in at
any time, a shock follows in the portions which are
deprived of their supports ; they first totter and then
collapse ; nothing encounters them to support their
weight. Then chasms and vast gulfs are opened 3
up, or it may be, after hanging a long time in the
balance, the ground settles down over what is still
left standing. We see the same thing happen ordi
narily as often as a part of the city suffers from a fire.
The joists are burnt through, or what gave support
to the upper part of the buildings is undermined.
Then the roofs after tossing about for a long time
fall in ; their swaying and oscillating continue until
they find a resting-place on solid ground.



X

ANAXIMENES affirms that the earth is itself the i
cause of the earthquake, and that nothing encounters
it from without to give it a shock. Within it, he
thinks, certain parts of its substance fall of themselves,
either loosened by moisture, or eaten away by fire,
or shaken off by the violence of air. But even in
absence of such active cause there is not wanting
sufficient to account for the loss or removal of some
portion of the earth. In the first place, all things



238 PHYSICAL SCIENCE BK. vi

fall through age, for nothing is safe from the ravages
of time, which waste even the solidest and strongest
edifice. In old buildings parts fall without being
knocked off, merely because they have more weight
2 than strength. So in the earth s body as a whole
it comes to pass that portions are loosened by age,
and being loosened, fall, causing shock to the things
above them. This they do primarily while they are
leaving their place ; for nothing, especially if it is
large, can be wrenched off without movement of
that to which it adhered. But further, when the
objects have fallen, they meet the solid earth and
rebound like a ball. When a ball falls, it jumps up
and bounces repeatedly, just as often, in fact, as
it recoils from the ground for a new flight. If the
loosened objects within the earth are carried down
into stagnant waters, this accident of itself causes
a shock to the vicinity through the wave cast up
by the weight of the objects shot suddenly down
from a great height.

XI

SOME attribute these earthquakes to fire, but
give different explanations of its action. When
fire causes intense heat at various points beneath
the earth, it must roll up a great cloud of vapour,
which can find no exit, and which dilates the air
by its high temperature. If the pressure of the
vapour is excessive, it scatters all obstructions ; but
if it is comparatively moderate, it merely causes
movement of the earth. We observe water smoke
when fire is applied. What the fire does to this
water in a narrow pot, one may suppose is done
on a much greater scale when a violent and wide-



xi AIR AS CAUSE 239

spreading fire causes immense extents of water to
boil. It then by evaporation from the overflowing
waters shakes violently whatever it strikes.



XII

MANY of the greatest authorities are persuaded that i
earthquakes are to be attributed to air. Archelaus,
who is well versed in the records of antiquity, speaks
thus : Winds are carried down into the earth s
hollows and recesses. When they are all full, and the
atmosphere is condensed to the utmost extent, the
air, which continues to come in, forces and thrusts
the former air, and with frequent blows first com
presses and then dislodges it. The air in its 2
endeavour to find room forces all the narrow
passages and tries to burst its barriers. Through
the struggle of the air as it seeks for an escape
it comes to pass that the earth is moved. This
explains why the approach of an earthquake is
preceded by still and quiet of the atmosphere ;
the force of the air which is wont to rouse the
winds is held in check in its nether abode. Even 3
on the present occasion of the earthquake in
Campania, although the season was winter, the
atmosphere was perfectly still and calm for several
days before it. 1 Well, then, did an earthquake
never take place when there was a wind blowing ?
On very rare occasions have there been two winds
blowing simultaneously. Still, such a thing is
possible, and is wont to occur. But if we admit
it as an established fact that two winds can be
in activity at one and the same time, why shouldn t

1 The text is uncertain, and the argument down to the end of the chapter
rather obscure.



2 4 o PHYSICAL SCIENCE BK. vi

it happen that [at times] one of them agitates the
upper air, the other the nether ? l



XIII

1 IN this category you may rank Aristotle and his
disciple Theophrastus, a man of pleasant though not
of superhuman eloquence, as the Greeks considered
him, and of easy, polished style. Let me unfold in
more detail what they hold in common : There is
always evaporation of some kind going on from
the earth, which is at one time dry, at another has
an admixture of moisture. When this, rising from
the lowest parts of earth, has been raised to the
utmost extent, and has no place beyond into which
to issue, it is borne back and returns upon itself.
The struggle of the air in its ebb and flow tosses
to and fro all obstructions it meets, and, whether
its egress is stopped or whether it escapes through
the narrow openings, it causes movement of the

2 earth and uproar. To the same school of opinion
belongs Strato, who made a special study of this
department of science, and was a diligent student
of natural philosophy. His verdict on the matter
is this : Cold and heat always move away from
one another in opposite directions, and cannot
remain in the same place. Cold flows into the
spot whence the influence of heat has departed ;
and, conversely, there is heat in the place whence
cold has been banished. The statement is beyond
doubt, but the contrariety of the two may become

1 The argument seems to be : Two winds can blow simultaneously. One
may be beneath the earth (causing or during earthquake), one above.
Therefore, stillness of the upper atmosphere is not a necessary concomitant
of earthquake. The fact has at times been otherwise.



xni EFFECTS OF TEMPERATURE 241

plain to you from the following : In the winter 3
season, when there is cold on the earth s surface,
the wells are warm, and caves and all underground
retreats equally so. The heat, yielding possession
of the upper regions to the cold, retreats down
there. When it reaches the lower regions, and
is accumulated there to the utmost, the denser it
is, the more powerful is it. To this a further
supply is added, to which what has already
gathered, and is compressed into a narrow space,
of necessity gives way. The same thing happens
from the opposite cause when a greater quantity of
cold is borne down to these recesses. All the heat 4
that lurks there gives way to the cold, and retires
to the narrow passages, and is driven onward with
great impetuosity. The nature of the two, as I
have said, does not allow agreement, or abode in
the same place. In its flight, then, and eager haste
to escape at all hazards the air pushes back and
tosses about all that lies near it. This is why,
previous to an earthquake, a roaring is usually
heard, through the tumult of the winds in the
earth s bowels. For not otherwise, as our poet 5
Virgil says, could

The earth bellow beneath our feet and the lofty peaks be moved,

were not this the work of the winds. In this
contest again there are ups and downs. There are
cessations in the massing of the heat and, in turn,
in its emission. Then the cold, too, is restrained
and gives way, but some day soon it will be more
powerful again. While, therefore, the alternating
forces rush to and fro, and the air moves hither
and thither, the earth is shaken.



R



242 PHYSICAL SCIENCE BK. vi



XIV

1 THERE are some who think that, while air and no
other cause produces earthquake, it operates in a
different way from that which Aristotle supposed.
Listen to what they say : Our body is irrigated
with blood, and with air which courses everywhere
along its own routes. We have some compara
tively narrow vessels through which they cannot
do more than pass ; some wider, in which they
accumulate, and from which they are distributed

2 to the members. So this whole body of the earth
at large has passages alike for water, which performs
the function of blood, and for wind, which might
be called simply the breath of its life. These two
encounter each other at some points, at some points
they are stationary. While in our bodies good
health is enjoyed, the movement of the veins pre
serves its rate undisturbed ; but when there is
malady the pulse beats more rapidly, the deep
breathing and panting betoken laboured, wearied
effort. In like manner the earth remains unshaken

3 while it maintains its natural position. But if any
flaw occur in it, there is a shaking, just as of a
body suffering from disease ; for the air which
flowed through it with regularity is violently
smitten, and causes its veins to quiver ; but not,
let me add, in the way, described a little above, 1
imagined by those who will have it that the earth
is a living creature. In that case the earth, just
as an animal does, would feel the agitation equally
all over. When a fever seizes any of us, it does

1 There seems a slight lapse of memory here. Cf. pp. 126, 196.



xiv EFFECTS OF AIR 243

not delay for a time its attack upon some parts,
but with uniform regularity spreads over them all.

Perhaps you had better assume, therefore, that 4
air from the surrounding atmosphere enters the earth.
As long as it has free egress, it glides through it
without doing harm ; but if it meet some obstacle
to block its way, then it is, to begin with, weighted
with the atmosphere that pours in on the rear ;
by and by it escapes with difficulty through some
chink, and makes its way with the greater violence
the narrower the opening is. That cannot take
place without a struggle, and a struggle involves
shaking of the earth. But if the confined air 5
cannot find even a chink by which to issue, it is
massed and becomes furious, and is driven round in
this direction and in that, overthrowing or bursting
one thing after another. It is excessively subtle,
and at the same time exceedingly powerful ; it can
worm its way into obstructions however great,
splitting and scattering whatever it enters. When
this occurs, then there is a regular tossing of the
earth. For the earth either opens to give room
to the wind, or, after giving room, is deprived
of its foundation and subsides into the very cavern
from which it allowed the wind to issue.



XV

SOME entertain the following opinion : The earth
is porous at many points, possessing not merely
those first shafts which it received as ventilators
at its creation, but many subsequently opened up
by various changes. In some places water has
washed away the soil that was on the surface ;



244 PHYSICAL SCIENCE BK. vi

part has been eaten away by torrents, while parts
have been exposed by the disruptive action of great
tides. Through the interstices thus produced air
enters. If it so happen now that the sea has
shut it in and driven it deeper, and the waves
prevent its escape by the same road, egress and
regress being alike closed, the air rolls about
within the earth. Its natural tendency is to hurry
straight forward, but as that path is closed, it
presses upward and lashes the earth, whose weight
lies heavy upon it.

XVI

1 I MUST further mention a view held by the majority
of writers, which probably I shall myself support.
The earth does not lack air within ; that everybody
knows. I do not mean merely the air which holds
it together and unites its parts, which exists even in
stones and dead bodies ; but I mean that fresh vital
air which supports all life. Unless the earth pos
sessed this store of air, how could she infuse it into
so many trees and crops, which derive their life from

2 this and no other source ? How could she nourish
all the different roots that sink into the soil in one
place and another, some merely attached to the sur
face, others sunk deeper, had she not an abundant
supply of the breath of life, which produces so many
varied growths and rears them with its nourishing
draught ? These are the slighter arguments that I
hitherto urge. Why, all the heaven we see, which
is shut in by fiery ether, the highest portion of the
universe, all these stars, whose number cannot be
conceived, all this concourse of heavenly bodies,
and, to mention only one more, this sun, that urges



xvi AIR NOURISHES THE UNIVERSE 245

his course so close to us, many times larger than
the whole circuit of the earth all these draw
their nourishment from materials of earth which
they share among them, and are sustained, of
course, by nothing else than the breath of the 3
earth. This is their nourishment, this their pas
turage. Now the earth would be unable to nourish
so many bodies of such size, larger even than
itself, unless it were full of breath, which it exhales
from every part of it day and night. For there
must be a large reserve of that from which so
much is sought and taken ; in fact, the supply to be
drawn from it is created for the occasion. The 4
earth would not possess a perennial supply of
air sufficient for the wants of so many heavenly
bodies, unless the elements issued and returned
alternately and were transmutable into one another.
But apart from this, it is necessary that the earth
be abundantly filled with it, and be able to draw
it forth from her hidden store. There is no
doubt then that a great quantity of air lurks
in the interstices of the earth, and a widely
diffused atmosphere occupies the hidden spaces
underground. If that is true, of necessity the
earth must often be moved, since it is full of a most
movable substance. No one, I suppose, can doubt
that there is nothing so restless, so capricious, so
fond of disturbance as air.



XVII

IT follows, therefore, that air should obey the law of
its being ; what is wont to be moved will sometimes
move other things. And when ? Whenever its free
course is checked. As long as it is not hindered it



246 PHYSICAL SCIENCE BK. vi

flows quietly along. When it is opposed and held
back it becomes furious, bursting all obstacles just
like that

Araxes that ever spurned a bridge.

2 As long as the river has a free easy channel it
rolls down its waters in due and regular succession.
But if through chance or by human agency rocks are
placed in its way to check its course, then it gathers
fresh strength from the barrier, and the more
numerous the obstacles opposed to it, the greater
the force that it musters to overcome them. For
all the water that accumulates behind, constantly
increases, and being at last unable to bear its own
weight manifests its violence through the havoc it
works in its descent, and escapes headlong down its
channel, bearing the very obstacles that blocked its

3 path. The same thing occurs with air, only that, in
proportion to its greater strength and mobility,
it is the more rapidly carried onward, and bursts
the more violently all that encloses it. From this,
of course, there is a disturbance in the part of the
ground under which the struggle has occurred. The
truth of this assertion may be proved from the con
sideration that often when an earthquake has taken
place, involving a breach of only some part of the
earth, wind has issued from it for several days.

4 This is recorded to have taken place in the earth
quake in which Chalcis suffered, as you will find
in Asclepiodotus, Posidonius pupil, in his discus
sion of my own topic of Physical Inquiries. In
other authors, too, you will find it stated that after
a chasm had opened up at one spot, in no long time
wind issued from it, having no doubt made for itself
the way along which it travelled.



xvin CHIEF CAUSE OF EARTHQUAKE 247



XVIII

THE chief cause of earthquake, therefore, is air, i
an element naturally swift and shifting from
place to place. As long as it is not stirred, but
lurks in a vacant space, it reposes innocently,
giving no trouble to objects round it. But when
any cause coming upon it from without rouses it, or
compresses it, and drives it into a narrow space,
in the first instance, to be sure, it merely retires
and roams about, its enclosure. But when oppor
tunity of escape is cut off, and resistance meets it
on all hands, then

. . . With deep murmur of the mountain
It roars around the barriers ; . . .

which, after long battering, it dislodges and tosses
on high, growing the more fierce, the stronger the 2
obstacle with which it has contended. By and by,
when it has traversed the whole space in which it
was enclosed, and has failed to find a way of escape,
it recoils from the side on which its impact was
greatest. It is then either distributed through
the secret openings which the earthquake of itself
causes here and there, or escapes through a new
rent. So uncontrollable is this mighty power. No
bolt can imprison wind ; it loosens every bond,
bears with it every weight, and insinuating itself
into the smallest crannies wins its release ; for by
the invincible power of nature it is free, especially
when roused, and asserts its right for itself. Air is 3
a thing no man can tame ; nothing will be found
which,



248 PHYSICAL SCIENCE BK. vi

When the winds struggle and the tempests roar,

Can restrain them by its sway and rein them by bonds and prison.

Doubtless the poets wished the place in which
the winds lay pent up underground to be con
sidered a prison. But they did not perceive either
that what was shut up is no longer wind, or
that what is wind can no longer be shut up.
What is shut up is at rest, and the atmosphere
is at a standstill ; whereas all wind is in flight.
4 Besides these arguments, there is a considera
tion by which it becomes manifest that motion
is brought about by air, namely, that our bodies
never tremble except when some cause produces
disturbance of the internal air, 1 which is contracted
by fear, grows sluggish in old age, languishes when
the veins are numbed, is checked with cold, or
after some attack of fever is quite driven from its
wonted course. As long as it flows unimpeded, and
moves in its wonted fashion, there is no quivering
of the body. When anything intervenes to prevent
its functioning, then being no longer able to main
tain what it upheld by its vigour, it fails, causing a
collapse of everything that it had sustained when
unimpaired.

XIX

1 WE must now hear what Metrodorus of Chios
desires to urge by way of opinion. I do not allow
myself the liberty of passing over unnoticed even
opinions that I disapprove ; it is better to have the
largest possible variety of views, and to condemn

2 rather than omit what we do not approve. Well,
then, what has Metrodorus to say ? He compares the

1 Or spirit : there is almost a play upon the ambiguous meaning of the
term.



xix SUBTERRANEAN VOIDS 249

subterranean disturbances to the voice of a person
who puts his head into a barrel and begins to sing
out. In that case there is a kind of quavering
as the voice extends and resounds through the
whole hollow space ; slight as the movement is, it
passes all round the vessel in which it is enclosed,
grazing its sides and causing disturbance all through.
In the same way the vast empty caverns that
stretch down beneath the earth have atmosphere
of their own, on which other air coming from above
falls with violence. The agitation produced differs
in no wise from that of the empty vessels which I
have just mentioned, when they resound through
shouting into them.



XX

LET us now go on to consider the authors who i
have alleged as causes all the different factors
mentioned, or, at any rate, several of them.
Democritus is one of those who think that several
are concerned. He asserts that the earthquake is
produced sometimes by air, sometimes by water,
sometimes by both. He pursues the argument
in the following way : Some portion of the earth
is hollow, in which a large quantity of water has
gathered. Part of this water is thinner and less
dense than the rest. When it is driven back by
a heavy mass descending upon it from above, it
comes violently against the earth, causing a com
motion of it. The fluctuating movement of the
water cannot take place without corresponding
movement of the body on which it impinges.
Besides, what we said a little above regarding air 2



250 PHYSICAL SCIENCE BK. vi

must be repeated in regard to water. When it
is accumulated at one place, which becomes too
small to contain it, it inclines in some particular
direction, and opens up a passage for itself, at
first by its mere weight, afterwards by the gathering
force of its current. Being long shut up it cannot
escape except down an incline, and it cannot drop
straight down with any gentleness, or without violent
shaking of the parts through which and on which it

3 falls. Now, if after it has begun its rapid downward
movement it is checked at any point, and the force
of the current is thrown back upon itself, it is driven
back on the earth which encounters it, and attacks
the earth at the point where it is most insecure.
Moreover, the ground is sometimes so saturated
with the moisture it has received into its heart that
it subsides to a lower level and its very foundation
is destroyed. The pressure is then exerted on the
part toward which the weight of the descending
waters most inclines. Air, too, sometimes urges
the water. If it presses with some degree of
violence, it naturally moves the part of the earth
toward which it has urged the gathering of the

4 waters. Sometimes, again, the air is driven into
passages through the earth, and in its search
for a way of escape causes a general movement.
The earth, as we know, is pervious to wind ; air
is too subtle to be excluded, too violent to be resisted
when excited to rapid movement.

Turning from Democritus to Epicurus, we find
the latter to assert that all the foregoing may be
causes of earthquake, but he tries to introduce
some additional ones. He criticises other authors
for affirming too positively that some particular
one of the causes is responsible, as it is difficult



xx CO MB IN A TION OF CA USES 2 5 1

to pronounce anything as certain in matters in
which conjecture must be resorted to. As he says, 5
then, water is capable of producing earthquake
by washing and rubbing off certain portions, the
weakening of which removes the support of what
was upborne by them when unimpaired. The
force of air is also capable of moving the earth.
Perhaps the air within the earth is set in violent
agitation by other air entering from without. Or,
perchance, it may be that the earth receives an
internal blow from the sudden fall of some portion
of it, and derives thence the shock. Or, perchance,
some portion of the earth is upheld, as it were, by
certain pillars and stakes, the injury or withdrawal
of which causes a tremor to run through the mass
they support. Or, perchance, a quantity of hot air e
turning to fire and assuming the character of light
ning courses along to the widespread destruction
of all obstacles it encounters. Or, perchance, some
wind stirs the sluggish marshy waters, whose stroke
in consequence shakes the earth ; or the tossing
of the air, increasing to violence through the mere
movement, is carried from the lowest depths right
up to the surface of the earth. Still, Epicurus is
satisfied that there is no more potent cause of earth
quake than air.

XXI

WE Stoics also are convinced that it is only air that i
can attempt such a feat as the production of an
earthquake, for than it nothing in the whole realm
of nature is more powerful, more energetic ; in
absence of it even the elements that are most violent
lose their force. It is by air that fire is kindled ;



252 PHYSICAL SCIENCE BK. vi

if you withdraw wind, water is sluggish. Water
becomes impetuous only when the blast tosses it
with violence. This force it is that has power to
scatter vast spaces of earth, to raise from the
depths new mountains, and to set in mid -ocean

2 islands hitherto unseen. Can any one doubt that
There and Therasia and this island which in our
days under our very eyes rose out of the Aegean
Sea, were carried up to the light by the force of
air ?

Posidonius will have it that there are two
different varieties in the movements of the earth,
each with its distinctive name. The one is a
quaking when the earth is shaken and moves up
and down ; the other is a tilting when, like a

3 ship, it leans over to one or other side. I am of
opinion that there is still a third variety, which we
have a special term to denote. Our forefathers had
good reason for speaking of a trembling of the
earth, for it is unlike either of the other kinds of
movement. On such an occasion things are neither
all shaken nor all tilted, but they quiver. In a case
of this kind no great damage is usually done ; while,
on the other hand, a tilting is far more destructive
than a shock ; for unless a contrary movement set
in very quickly from the other side to restore the
level, downfall follows of necessity.



XXII

THESE movements being dissimilar, their causes are
likewise different. Let us deal first with the shaking
movement. If great loads are being conveyed by
a row of many waggons, and the wheels, under



xxii EARTHQUAKES THAT SHAKE 253

the unusual strain, fall into the ruts of the road, one
feels the earth shaken. Asclepiodotus has put it
on record that on one occasion the fall of a rock
that was torn off from the mountain-side caused
by the tremor the collapse of some houses in its
vicinity. Just the same thing may occur beneath
the earth ; parts of the overhanging crags may
be loosened and fall with great weight and noise
upon the floor of the cavern beneath, and with a
violence proportionate to the weight of the mass
and the height of the fall. The whole roof of the
subterranean valley is disturbed by an occurrence
of this kind. It is conceivable, too, that rocks are 2
not always wrenched off by their own weight ; when
rivers roll over them, the constant moisture weakens
the joints of the stone, and day by day bears away
part of its fastening, causing abrasion, so to speak,
of the skin in which the stone is enclosed. The long
waste of ages, through constant daily rubbing, by
and by so weakens the fastenings that they cease
to be able to sustain their burden. Then blocks 3
of vast size fall down, then the crag hurled head
long will not suffer anything to stand that it strikes
in the rebound from its fall, but

Comes away with a roar ; and all things seem suddenly to rush
headlong,

as our- countryman Virgil says. Such must be the
cause of the earthquake that shakes the ground
beneath. Now I must pass on to the second kind.



XXIII



THE earth is naturally full of cavities, containing
much empty space. Through these cavities air



254 PHYSICAL SCIENCE BK. vi

roams. When an excessive quantity has entered
and cannot escape it shakes the earth. This ex
planation is approved by others, too, as mentioned
a little above. Perhaps the crowd of witnesses
will impress you. The view has the adhesion of
Callisthenes, and he is a man not lightly to be
set aside. He was endowed with a lofty intellect,
and he dared to brave the wrath of a king. His
death is an eternal blot on the memory of
Alexander, which no valour and no success in

2 war can ever remove. As often as it is said,
Alexander slew many thousands of the Persians,
the retort will be, And Callisthenes too. As often
as it is said, He slew Darius, in whose hands there
was then a mighty kingdom, the retort will be,
Yes, and Callisthenes too. As often as it is said,
He conquered all lands right up to the Ocean, the
Ocean likewise he essayed with fleets strange to
its waters, from a corner of Thrace he extended
his empire to the bounds of the East ; it will
also be said, Yes, but he slew Callisthenes.

3 Granted that he surpassed all former precedents of
generals and kings, yet of all that he did, nothing
will match his guilt in slaying Callisthenes.

Well, this Callisthenes, in the treatise in
which he gives details of the sinking of Helice
and Buris, and discusses the disaster which sent
them into the sea, or the sea into them, says
what I have said at a previous point. Air, he
says, enters the earth by hidden openings under

4 the sea, just as everywhere else. By and by,
when the path is blocked by which it had
descended, and the resistance of the water in the
rear has cut off its retreat, it is borne hither and
thither, and encountering itself in its course it



xxin ACTION OF AIR 255

undermines the earth. That is the reason why
land over against the sea is most frequently
harassed by earthquakes ; and hence it is that
Neptune has been assigned this power of moving
the earth. 1 Any one who has learned the elements
of Greek knows that he is called among the Greeks
Earthshaker



XXIV

I SHALL be ready to allow that air is the cause of i
this form of destructive earthquake. But I shall
have some criticism to offer as to the method by
which it enters the ground. Does it enter by
fine openings that the eye cannot detect, or by
larger and more evident ones ? Does it come from
the depths of the earth, or does it pass through
the surface too ? The last-mentioned view seems
inconceivable. In our bodies the skin keeps out
air, which finds no entrance except that through
which it is inhaled. And even when taken in by
us, it cannot settle except in the looser portion of
the body. It does not remain among the sinews 2
or muscle, but in the bowels and the open vessels
of our internal organs. The same arrangement may
be suspected in regard to the earth s interior from the
very fact that the movement in an earthquake is not
on the surface of the earth or about the surface, but
beneath in the lowest parts. A proof of this is that
seas of immense depth are tossed up, no doubt
from the movement of the ground over which they
spread. It is therefore probable that the earth 3
is moved in its depths, and that the air is formed

1 The usual reading, marts = sea, contradicts the argument; it cannot
surely be right.



256 PHYSICAL SCIENCE BK. vi

there in the immense caverns. Nay, says some
critic, but just as when we shiver from cold a
trembling follows, so, too, the earth is shaken by
air affecting it from without. This I deny can
by any possibility occur. Why, the earth must
get a chill in order to have the same happen to
it as to us, w r hom an external affection drives into

4 a shuddering fit. I should quite allow that the
earth shows symptoms of much the same kind as
we do, but the cause is wholly different. An injury
of a deeper kind, more toward its centre, must affect
it, the very strongest proof of which may be found
in the fact that when through violent earthquake
the soil is laid open in wide destruction, the
chasm sometimes takes in and buries whole cities.

5 Thucydides tells us that, about the time of the
Peloponnesian War, the island of Atalanta, either
wholly, or, at any rate, for the most part, was
swallowed up. You may take Posidonius for
witness that the same thing happened to Sidon.
But we do not require evidence of this. Within
our own memory the earth has been torn by
internal movement, adjoining places have been
rent asunder, whole plains have disappeared. I will
now explain how I suppose this sort of thing to
occur.



XXV

WHEN air has completely filled a large vacant space
within the earth, and has begun to struggle and
meditate escape, it lashes again and again the sides
of the enclosure within which it lurks, and right over
which, as it happens, cities are sometimes situated.
The shaking is at times so violent that buildings



xxv FAMOUS EARTHQUAKES 257

standing above the area of disturbance are thrown
down. Sometimes it goes to such lengths that
the walls by which the whole roof of the cavern is
supported fall right down into that vacant under
ground space, and cities sink entire into the
unfathomed depths. Long ago, if one may believe 2
the story, Ossa and Olympus were united; subse
quently they were separated by an earthquake, and
the one great mountain was split into two. Then
the Peneus made its escape, draining the marshes
with which Thessaly was overspread, and drawing
off the waters, which from want of exit had hitherto
formed a lake. It was an earthquake that let loose
Ladon, the river which flows between Elis and
Magalenopolis. What, it is asked, do these facts
go to prove ? Simply that air gathers in the spacious 3
caves for what other name can I apply to the
empty places under the earth ? Were this not so, 1
great spaces of the earth would be convulsed, and
many of them would totter to ruin at one and the
same time. As it is, only small portions suffer, nor
does a shock ever extend as much as two hundred
miles. Look at the recent one, the marvellous tales
of which have filled the whole world ; it did not
pass beyond Campania. Need I say that when 4
Chalcis felt the earthquake shock Thebes did not
fall ? when Aegium suffered, Patras, which is quite
close by, only learned by report about the earth
quake ? That mighty shock, which swallowed up
the two cities Helice and Buris, stopped short
of Aegium. Plainly, then, the movement extends
only such distance as the empty space underground
stretches.

1 I.e. were the air distributed all through the earth.



258 PHYSICAL SCIENCE BK. vi



XXVI

1 To prove my point I might have used, somewhat un
fairly perhaps, the authority of the great writers who
relate that Egypt never experienced an earthquake
shock, the reason they allege for it being that it is
all composed of mud. If one may believe Homer,
Pharos used to be as far from the mainland as a ship
under full sail could reach in a day s voyage ; but it
has now become attached to the mainland. The
Nile s swollen stream brings down great quantities of
mud, and by adding it from time to time to the existing
land it has by an annual increase constantly carried

2 forward the coast of Egypt. The country thus is
composed of rich loamy soil without interstices, as
it has become solid just by the drying up of the mud.
The composition of the mud was close and firm,
the particles of it being stuck together ; no vacant
space could intervene, since the solid was always
being added to by the liquid and soft slime.
But Egypt is, as a matter of fact, subject to earth
quake ; and Delos, too, though Virgil bade it stand
fast,

And granted that it should be a settled land of tillage, and should
laugh the winds to scorn.

The philosophers, too, a credulous set of people,
relying on Pindar s authority, said that it did not
experience movement. Thucydides asserts that
in former times it was unshaken, but sustained a
shock about the time of the Peloponnesian War.

3 Callisthenes asserts that the same thing happened
on another occasion also. Among the numerous
portents these are his words by which warning was



xxvi THE SEA NO PROTECTION 259

given of the overthrow of the two cities Helice and
Buris, the most remarkable were the appearance of
a huge pillar of fire and the earthquake shock in
Delos. Yet he will have it that the island is com
paratively firm for the reason that it is placed on the
sea and has hollow crags and porous rocks, which
afford a way of escape to air imprisoned in them.
For this reason, too, islands have, he thinks, a 4
firmer soil, and cities are safer in proportion to
their proximity to the sea. The falsity of such an
opinion surely Pompeii and Herculaneum learned
to their cost. Add now the fact that every sea-
coast is particularly subject to earthquakes. Paphos,
for instance, was more than once ruined, and the
famous Nicopolis is already intimately acquainted
with this mischief. Cyprus is surrounded by a
deep sea, but is subject to shocks. Tyre is as
regularly shaken by earthquake as it is washed by
the waves. Such, then, are for the most part the
explanations that have been suggested for the
trembling of the earth.



XXVII

WE must now essay an explanation of certain i
peculiar features which are said to have occurred in
the recent Campanian earthquake. A flock of six
hundred sheep is asserted to have been killed in the
district near Pompeii, and there is no reason to
suppose that this happened to the sheep through
fright. We have said that after great earthquakes
it is usual for a pestilence to occur. And no
wonder, since in the depths of earth many deadly
poisons lurk. In fact, the very atmosphere there, 2



260 PHYSICAL SCIENCE BK. vi

being stagnant through some fault in the earth or
the sluggish movement and the everlasting darkness
that prevails, is dangerous to breathe. Or being
poisoned by the fumes of the internal fires, when it
is released from its long inactivity, it taints and
pollutes this pure clear air above, and brings new
forms of disease to those who inhale the unwonted
draught. You remember, too, that we found the
water lurking in the secret depths to be useless
and even pestilential, since activity never stirs
it, and the free breath of heaven never ruffles it.

3 Being therefore thick and covered beneath gross
eternal darkness it contains only elements that are
pestilential and injurious to our bodies. So, too, the
atmosphere, which mingles with it and lies amid
these marshes, scatters far and wide its poison when
it issues out, and kills those who breathe it. The
flocks, which the pestilence is wont to attack, feel
the poisonous effects more readily, because they are
more greedy in feeding. They live for the most
part in the open, and they drink a great deal of
water, which is chiefly responsible for the pestilence.

4 Sheep are of rather delicate constitution, and, as
they keep their heads close to the earth, I am not
surprised at their being attacked by the infection ;
they receive the blasts of tainted air just as it issues
from the ground. If it had issued in greater volume,
it would have injured man too. But the abundant
supply of pure air counteracted it before it could
rise high enough to be breathed by any human
being.



xxvin POISONS UNDERGROUND 261



XXVIII

Now you may infer that the earth contains many i
deadly elements from the mere fact that so many
poisons grow of themselves without being sown ;
the soil no doubt contains seeds of evil as well as of
good. Is it not the case that, earthquakes apart,
in several places in Italy a pestilential steam is
emitted through certain openings, which it is not
safe for either man or beast to breathe ? Even birds,
if they meet it before it is neutralised by the purer
breath of heaven, fall in mid -flight ; their bodies
become livid, and their jaws swell just as if they had
been strangled. As long as this air is contained in 2
the earth and escapes by a narrow opening, it has no
greater power than to kill creatures that look down
into, or voluntarily approach too near, it. But when
for centuries darkness has brooded over it, and the
gloom of the place has increased the infection, it
becomes more dangerous through mere lapse of
time ; the more sluggish it is, all the more deadly
does it become. Then when it has gained an exit it
lets loose all that mischief conceived in the cold
shades through endless ages of nether darkness,
tainting with it the atmosphere of our realms of
earth. The better is ever conquered by the worse. 3
Even that purer air of heaven then changes to
pestilential. Thence come sudden and continuous
deaths, and portentous forms of disease that spring
from unexampled causes. The disaster is long or
short lived, according to the strength of the sources
of infection. Nor does the plague cease until the
freedom of heaven and the tossing of the winds
have banished l that fatal air.

1 Or purified.



262 PHYSICAL SCIENCE BK. vi



XXIX

1 THROUGH fear some people have run about as
if distracted or mad. For fear, even when in
moderation and confined to individuals, shatters
the mind s powers. But when there is public
alarm through fall of cities, burying of whole
nations, and shaking of earth s foundations, what
wonder that minds in the distraction of suffering
and terror should have wandered forth bereft of
sense ? It is no easy matter in the midst of
overmastering evils not to lose one s reason. So
it is, as a rule, the feeblest souls that reach such

2 a pitch of dread as to become unhinged. No one,
indeed, has suffered extreme terror without some
loss of sanity ; one who is afraid is much like a
madman. But some quickly recovering from the
alarm regain self-possession. Others it more
violently disturbs and reduces to sheer madness.
Hence during times of war lunatics are to be met
wandering about. On no occasion will one find
more instances of raving prophets than when mingled
terror and superstition have struck men s hearts.

I am not surprised that a statue is split by an
earthquake, after I have recounted that mountains
have been separated from mountains and the ground
itself burst asunder down to its depths.

3 These places, once convulsed by the force of vast ruin
Such the power of change in the lapse of lengthened ages !
Leaped asunder, they tell us, whereas hitherto both lands
Were one ; into their midst rushed the deep with its mighty

billows,

Cutting off the Italian from the Sicilian side ; fields and cities
Were parted in sea-line and washed by the narrow tide that

flowed between.



xxix STATUES AND KINGDOMS SPLIT 263

One sees whole regions torn from their place, and
what was once contiguous, now lying beyond the sea.
One sees a separation of cities and nations when a
part of nature is roused by internal motion, or the sea
or fire or air has assailed some point ; for their force
is marvellous, since it has a boundless reserve from
which to draw. Though its rage is vented at but one 4
point, yet it has the world s whole strength to rein
force its wrath. Thus it was that the sea tore away
Spain from the mainland of Africa. Thus it was
by the flood, which the greatest of poets have
celebrated, that Sicily was cut away from Italy. The
movements that proceed from depth have much more
force. They are more energetic, as their effort is
concentrated upon a narrow area. Enough has
now been said to show what mighty deeds these
earthquakes have wrought and what wondrous sights
they have displayed.

XXX

WHY, then, should one be amazed that the bronze i
of a single statue is burst, and that, not even solid,
but hollow and thin ? as likely as not air in seeking
an escape has got enclosed in it. And does not
every one know that buildings are sometimes ob
served in time of earthquake to split at the corners
and be united again ? Other things badly set upon
their base, and loosely and carelessly put together
by the workmen, have been known to be welded
firmly together by the repeated shaking of the
earthquake. If it splits whole walls and whole 2
houses, and rends the sides of great towers, which
are constructed of solid masonry, and scatters the
piles that support the foundations of great works,



264 PHYSICAL SCIENCE BK. vi

why should one think it worthy of remark that a
statue had been cut equally into two from base to
summit? But why, it may be asked, did the shock last
3 for several days ? For Campania went on trembling
continuously, more gently it is true, but still causing
great damage, because what it shook was already
shaken and crushed. Things stood so insecurely as
to require only a slight shake, but not a push, to
bring them down. The explanation of the prolonged
shaking is no doubt that all the air had not yet
escaped, but though the greater part was discharged,
a remnant was still roaming about here and there.



XXXI

THERE is yet a further proof that you may un
hesitatingly add to the others that go to show that
all these phenomena are the outcome of air. After
the most violent shock that cities and provinces can
experience has spent itself, another of like violence
cannot immediately follow ; after the crisis there
are only slight shocks, just because the most violent
one has opened a way of escape for the struggling
winds. The remains of the air that is left have not
the same power, nor do they require to struggle ;
they have now found a way of escape, and follow the
path by which the first and greatest shock issued.

I am of opinion, too, that the observations of a
certain learned and grave philosopher of my acquaint
ance deserve to be put on record ; he happened
to be taking a bath when the earthquake occurred.
He asserted that he saw the tiles with which the
floor of the bathroom was paved, separate one
from another and unite again. At one moment,



xxxi A PHILOSOPHERS OBSERVATIONS 265

when the pavement opened, the water was taken
in through the joints, the next, when the pavement
closed, it was forced out all bubbling. I have heard
the same learned man relate that he had seen soft
materials undergo more frequent but more gentle
shocks than materials naturally hard.



XXXII

So much, my esteemed Lucilius, with respect to the i
mere causes of earthquakes. Now we must adduce
some considerations that will tend to reassure us in
face of the perils of earthquakes. After all, it con
cerns us more closely to acquire resolution of mind
than erudition, and yet the former cannot be had
without the latter. Assurance comes to the mind
from no source but elevating studies and the con
templation of nature. Is there any one, I say,
that reflects upon causes, who will not be reassured
and emboldened by this late catastrophe in Cam
pania to face disasters of all kinds ? Why should 2
I fear man or beast, bow or lance? Far greater
perils are ever lurking for me. Lightning and earth
shock, and all the great forces of nature, aim their
blows at us. Death must therefore be resolutely l
challenged whether its attack be with vast 1 over
powering onset or by ordinary means of daily oc
currence. It is of no moment how threatening its
approach, or how great the engine it brings up
against us. The life it asks of us is a very little
thing. It will be taken from us by old age, or by 3
a little pain in the ear, or by a superabundance
of tainted moisture within, by food that the stomach

1 It would seem that ingenti and aequo have by some means got trans
posed in the ordinary texts. Gercke reads saevo for aequo.



266 PHYSICAL SCIENCE BK. vi

cannot assimilate, or by a slight injury to one s toe.
Man s life is a paltry affair, but a mighty affair is
the contempt of life. He who can despise life may
look unmoved upon the tossing of the sea, even
though all the winds have roused it, even though
by some upheaval of the world the tide has turned

4 the whole Ocean bodily upon the land. Unmoved
he will behold the fierce forbidding aspect of the
thundering heavens, yes, though heaven itself be
crushed and unite its fires for the destruction
of mankind and of itself first of all. Unmoved
he will behold earth s framework rent and earth s
foundations yawning beneath. Though the realms
of the nether world be uncovered, he will stand
over the abyss still dauntless, and into the pit into
which he is doomed to fall he will perhaps leap.
What is it to me how great the powers by which
I perish ? To perish is itself no great matter.

5 Wherefore, if we desire to be happy, to be
harassed by no fear either of men, or gods, or
circumstance, to despise fortune with her super
fluous promises and her contemptible threats, if
we desire to live the peaceful life, and to vie with
the very gods in happiness, then we must carry
our life in our right hand. Whether snares or
diseases attack it, the swords of foes or the crash
of falling tenements, or the downfall of earth itself,
or the violence of widespread fire enveloping city
and field in common disaster, let who will take it.

6 What more do I owe life than to encourage
it on its journey, and to despatch it with good
wishes ? Go resolutely, go prosperously ! There
must be no hesitation in rendering back life. It
is merely a question of time, not of fact. What
you are doing must be done some day. Beseech



xxxii CONSOLATION AGAINST DEATH 267

not nor fear, nor draw back as if starting to
face some peril. Nature, who bore you, waits
your coming to a place better and safer than
earth. There is no earthquake there, friend, no 7
winds clashing with loud noise of cloudy sky, no
fires to waste province and city, no fear of ship
wreck swallowing up whole fleets, no armies ar
rayed with opposing banners, or common fury of
hosts prepared for mutual destruction, no plague,
no pyres lit up around the promiscuous resting-
place of slaughtered nations. If death is a light
affair, why fear it? If it is heavy, then rather let it
fall once for all than be always hanging over us.
Should / fear to perish when earth must perish s
before me, when the powers that shake are shaken,
when they hasten to our destruction only through
their own? The sea received Helice and Buris
entire ; shall I fear for one poor body ? Ships
sail over the site of two towns, aye, towns that
we know well, that the record preserved by letters
has brought to our intimate knowledge. How
many others have been sunk in other places ? how
many nations has either earth or sea engulfed?
Shall I rebel against my end when I know that 9
I am not endless? nay, when I am fully assured
that all things come to an end, shall I fear my
latest sigh ?

Wherefore steel yourself, Lucilius, with all
your might against fear of death. This fear it is
that drags us down ; this it is that torments and
destroys the life it tries to preserve. It magnifies
all those dangers, earthquakes and lightnings, and
the rest. You will be able to bear them all
resolutely if you but reflect that short and long
in life make no difference. It is but hours we lose. 10



268 PHYSICAL SCIENCE BK. vi

But suppose it is days, or months, or years, what
we lose is, surely, bound to perish. What differ
ence, pray, is it whether I manage to reach them
or not ? Time flows on ; it leaves behind those
most eager to seize it. Neither what is to be is
mine, nor what was. I am poised upon a point
of fleeting time ; it is a great thing to have been
moderate in one s ambitions. Laelius the Wise
made a neat retort once to a person who said, I am
ii sixty years old : you mean, said he, the sixty you
no longer are. 1 We show our failure to grasp the
terms of this elusive life of ours, and the conditions of
time that is never our own, in reckoning up as ours
years that are now lost. Let us fix this in our
minds, and constantly remind ourselves, I must die.
When ? What matter is that to you ? Death is a
law of nature ; death is a tribute and a duty imposed
on mortals ; it is the remedy of all ills. Whoever
now fears it will one day long for it. Giving up all
else, Lucilius, make this your one meditation, not
to dread the name death. By long reflection make
death an intimate friend, that, if so required, you
may be able even to go forth to welcome it.



1 It is almost impossible to express in English the play on
French is more amenable. "J ai soixante ans ! Parlez-vous des soixante
ans que vous n avez plus ? " NISARD.

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