THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

LOS ANGELES

8I^Rr?r"

PHYSICAL SCIENCE IN THE
TIME OF NERO

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PHYSICAL SCIENCE

IN THE TIME OF NERO

BEING A TRANSLATION OF THE
QUAESTIONES NATURALES OF SENECA

BY

JOHN CLARKE, M.A.

LECTURER ON EDUCATION IN THE UNIVERSITY OF ABERDEEN

WITH NOTES ON THE TREATISE BY

SIR ARCHIBALD GEIKIE

K.C.B., D.C.L., Sc.D., LL.D.

PRESIDENT OF THE ROYAL SOCIETY

MACMILLAN AND CO., LIMITED

ST. MARTIN'S STREET, LONDON

1910

Plurimum ad inveniendum contulit qui speravit posse reperiri.

SENECA, Q.N. vi. v. 2.

College
library

Ql5

PREFACE

THIS book is intended primarily for English readers,
to most of whom it will probably be at least new.
Thomas Lodge, the well-known dramatist, pub-
lished in 1614 a translation of the whole of Seneca's
prose works (except the Apocolocyntosis), but no
English editor or commentator seems to have
turned his attention to the Quaestiones Naturales,
either before or since. Lodge's translation, a folio
volume of nearly a thousand pages, was probably
very good for its day, but is now out of date.

The Introduction is designed to give a setting
to the translation, and to answer a few of the
questions that would naturally occur to the mind of
an intelligent reader who was not a classical scholar.
In the Index also some details are included that
may be helpful to those who have neither time nor
opportunity for hunting up historical and other
allusions in books of reference. The object has
been to make the volume self-interpreting, though
it may be that the course has not always been
judiciously steered between too little and too much.

The Quaestiones Naturales must be regarded as
occupying historically an important position. It
was the latest deliverance of the classical world

672785

PHYSICAL SCIENCE

upon the subject of physical speculation. Its
currency during the Middle Ages rendered it for
many centuries the chief authority in science in
Western Europe. Its cosmology represented not
only popular but also educated opinion, and became
the source of many of the accepted ideas concerning
the universe that passed into early modern litera-
ture in our own and other countries.

Indebtedness to editors of Seneca and to others,
which has been very great, is acknowledged as
fully as possible in the Introduction and elsewhere
where help has been availed of. The interest
taken in the book by various friends is also grate-
fully acknowledged. Professor Sir Joseph Larmor
and Professor J. Arthur Thomson have made
several useful suggestions. Professor Herbert
J. C. Grierson has very kindly read the proofs and
given valuable assistance in other respects. But
my chief acknowledgments are due to Sir Archibald
Geikie. To him the translation owed its inception :
his constant aid and encouragement have enabled
me to complete a task from which I should probably
have otherwise shrunk. I am indebted to him also
for the Commentary appended to the translation,
in which the questions treated by Seneca are con-
sidered from the point of view of modern Science.
It has been to him a labour of love : may our
readers enjoy something of the same satisfaction !

J.C.

OLD ABERDEEN,

September 27, 1909.

1

CONTENTS

PREFACE . . . v

INTRODUCTION . . xxi

BOOK I

[METEORS, HALO, RAINBOW, MOCK SUN, ETC.]
PREFACE

PAGE

CONTRAST between human (moral) philosophy and divine (natural,
physical). The sublime character of the latter which lifts us above
the contemplation of the littlenesses of the earth and earthly life
to the knowledge of God and His nature. Compared with
astronomical conceptions and dimensions the world of man is but
as a threshing-floor, the haunt of ants. The mind of man attains
its true height in contemplation and investigation of these sublime
facts. Some of the problems thus raised ..... 3

CHAP.

I. Meteoric fires — she-goat, kid, etc. Occasions of their appearance ;

connection of portent with event. Explanation of the phenomena.
They may be due to pressure of the atmosphere. Aristotle attri-
butes them to the effect of terrestrial evaporation : difference of
density causes various outbursts of this kind. They are analogous
to lightning, but less violent ....... 8

II. Halos, Produced by the light of a heavenly body striking the

surrounding air and forming a circle as a stone does when thrown
into a pond. Formed far away from the heavenly body and
comparatively near the earth in the region of the wind. Require
a particular state of the atmosphere neither too dense nor too
thin. More frequent at night than day for this reason : by day
the sun rarefies the air too much by its heat. Method of dis-
sipation gives indication of wind or rain. Calmness a condition
of formation, as in the analogous case of water . . . . 12

III. Rainbows. Generally by day, produced by inequalities of surface
and density in clouds. Another species seen in a burst pipe or a
fuller at work. Various explanations. Light and shade will not
explain the varied colours. Some explain the rainbow as a con-
fused reflection of the sun from individual drops of rain :
every bounded surface, large or small, thus reflects — fish-pond
and dew-drop equally. Aristotle attributes the confusion of colours
to weakness of hum m sight ; parallels may be found in persons
whose sight is abnormally weak. As the innumerable drops,

vii b

PHYSICAL SCIENCE

CHAP. PAGE

apparently without intervals, fall, human vision fails to dis-
tinguish severally the reflections of the sun, which thus become
blended and confused. Vision is similarly deceived in the case of
an oar in water, apples in a glass globe, etc., even in the size and
movements of the sun himself. At any rate the rainbow requires
both sun and cloud, and these opposite to each other. These
two in operation produce the varieties of colour . . . 1 6

IV. That the rainbow is an image is shown by the relation of sun to
cloud in position, by the rapidity of formation and dispersion.
Artemidorus' explanation of the shape of the cloud (concave),

and the consequent position of the red in the rainbow . . 22

V. Arguments to show that the cloud is coloured by the sun, like a

dove's neck or a peacock's tail, and that the rainbow is not a
reflection of the sun. The position (opposite) would be equally
necessary in this case. Answer to this contention by Posidonius.
The colour effects. Author agrees with Posidonius' position but
not his arguments. The only proof is the geometrical one. . 23

VI. Arguments from the size — never more than a semicircle — and
shape of the bow. As the colour, whether real or reflected, is
derived from the sun, so must also the shape be. The size is
accounted for by the magnifying power of water, glass, etc.

The sun as he appears in the rainbow is seen through moisture . 28

VII. The arguments from the dispersion of the sun's rays through glass
(prism). Contention that they confirm author's view . . 30

VIII. The form once more ; why it is never larger than a semicircle.
A wrong explanation refuted. Explanation of Aristotle's remark
as to the seasons of rainbows, in summer only in the morning or
evening, in autumn at any time . . . . . . 31

IX. Streaks or weather-galls. Merely abortive or imperfect rainbows . 33

X. Relations and differences of halos, bows, and weather-galls . . 34

XI. Mock suns. Their appearance and position in relation to the sun.
They are a reflection of the sun in a suitable medium . . 34

XII. The formation of a mock sun may be compared to the image of
the sun in eclipse as seen reflected in a dish of oil or pitch : the
medium must be adapted to give the impression. The mock sun
requires a certain consistency of cloud, failing which, a different
effect is produced — obscuration, dissipation, etc. . . . 35

XIII. There may be two mock suns simultaneously. Some think the
one is a reflection of the other, the clouds acting as mirrors set
opposite to one another. Mock suns, especially in the South, are

a sign of rain ......... 36

XIV. Other celestial fires. "Cave meteors^" "Barrel meteors"
" Chasms" with a brief description of each. The rapidity of
their flight, just as of lightning, deceives the sight. Their origin

and cause. They indicate wind . . . . . . 37

XV. Gleams (flashes, <rt\a). Their production and motions, varieties
of them. Some do damage. Some are analogous to comets.
"Bearded," " torches" "cypress " are different kinds. "Beams "
and " barrels " may be of the same class. A curious case where
such an appearance raised an alarm of fire. They are real fires.
On the contrary, rainbows and halos are mere reflections.
Mirrors have this wonderful power of false presentation . . 39

CONTENTS

CHAP. PAGE

XVI. The "mirrored den" of Hostius Quadra . . . . 41

XVII. The philosophy of the looking-glass. The evolution of mirrors.
Mirrors of full length are now used. They cost a fortune greater
than the Senate gave Scipio's daughters. A harmless necessary
device has become an instrument of luxury, the adornment of
women, the burden of men, nay, part of the kit of the soldier . 44

BOOK II

[THE NATURE OF AIR. THUNDER AND LIGHTNING]

[I. -XI. PREFATORY to treatment of thunder and lightning, descriptive
of the nature of the air, in which these phenomena occur. ]

I. Divisions of physical science — astronomy, meteorology, geography.

Cross divisions, e.g. earthquakes, belong to meteorology, being
produced by air ; so the earth, as a planet, belongs to Astronomy
but its properties belong to Geography . . . . . 51

II. Unity and composition in bodies. The analogy of the seen applies

to the unseen. The atmosphere is possessed of unity (unitas) . 52

III. Parts and material of bodies distinguished. In the human body
blood is both ......... 54

IV. The atmosphere is an integral part of the universe : has unity . 54

V. The earth is both part and material of the universe. From it

nourishment is supplied to the latter . . . . . 55

VI. The atmosphere has unity — is not compact of atoms, otherwise it
could not exert tension, which is one of its main features, with
endless manifestations . . . . . . . . 55

VII. There is no vacuum in the air, as the analogy of.water shows . 57

VIII. The exertion of tension presupposes tensibility, just as motion
does mobility. Its existence in air proved by the effects of air,
which tosses about mountains, houses, walls, etc. The propaga-
tion of sight and sound proves the same . . . . . 58

IX. Its tension is seen in raising water, as in the jet in the amphi-
theatre. Proofs from a ship upborne of water, a quoit flung from

a height, sound heard through a wall . . . . . 59

X. Varieties of density and temperature in the atmosphere : the

central layer is coldest ........ 60

XI. The lower parts are most subject to change. The cause of this
is in part the earth, in part the sun, moon, and other stars.
So much by way of preface to explain the nature of that atmo-
sphere in which thunder and lightning occur . . . . 61

XII. Lightning, thunder-bolt, thunder. All agree that they occur in
the clouds, but different explanations are given of their cause and
relations. Anaxagoras connects them with the ether ; Aristotle
says they are due to exhalations of various kinds, from the earth,
coming in contact with the clouds . . . . . . 62

XIII. The fire cannot be inherent in the clouds and fall from them.
When it so comes it is forced ....... 64

PHYSICAL SCIENCE

CHAP. PAGE

XIV. There is nothing inconsistent with this in the explanation given
(I. xv.) of meteors. There may be an analogy with what is
observed in cases of fire when isolated groups of houses take fire
through gradual accumulation of heat . . . . . 65

XV. Some (Stoics) think that spontaneous combustion takes place in

the air 66

XVI. Difference between a flash of lightning and a bolt ... 66

XVII. Some explain the noise of thunder as due to hot meeting cold,

as in the case of hot iron plunged into water .... 67

XVIII. Anaximander attributes the effects to air and explains all the
phenomena by reference to it . . . . . . . 67

XIX. Anaxagoras says it is the ether that acts on the lower atmo-
sphere to produce them : it sends out fire . . . . 68

XX. Diogenes of Apollonia thinks that fire and air interact, pro-
ducing one another, as may be observed in the various phenomena 68

XXL Authorities discarded : independent explanation. A flash and

a bolt are fire in some form : they differ only in degree . . 69

XXII. Analogy of fire on earth : it must apply above. Lightning due
either to impact or friction. Hurricanes are a sufficient cause of

the former .......... 70

XXIII. Clouds and air may through friction also be a cause. The fires

so produced are insubstantial and evanescent . . . . 71

XXIV. Fire by reason of its lightness levitates, just as water gravi-
tates. But in the case of a bolt it is forced down, contrary to its
nature, like a " weeping " tree . . . . . . 71

XXV. But it is said that wet clouds produce fire. How ? . . 72

XXVI. There is no inconsistency in the combination in the same
cloud of potential fire and water. A log burns at one end,
exudes moisture at the other. An island on each of two occa-
sions was thrown up by fire in the Aegean Sea, fire overcoming
water. And clouds are, as a matter of fact, required for light-
ning : exceptions to this are only apparent . . . . 72

XXVII. Different kinds of thunder. The growling and the crashing,

with their causes ......... 75

XXVIII. In order to the sound of thunder, clouds of a particular
shape must meet in a particular way. A bladder does not burst
with a report if cut. A broad simultaneous blow over the whole
cloud is necessary to an explosion . . . . . . 76

XXIX. The proper shape and the rupture of the cloud are necessary.
Compare drums, etc. . . . . . . . . 77

XXX. According to some, clouds are not necessary to thunder :
witness eruptions of Etna and the overthrow of Cambyses' army,
where particles of sand were the medium of the thunder and
lightning. But in this case, too, a cloud was formed, it may be,
a denser, and more solid than one composed of mere air, before

the sound was emitted . . . . . . . . 77

XXXI. Strange effects of lightning 78

XXXII. Portents and events, their undoubted and widespread con-
nection .......... 79

XXXIII. Thunderbolts. Threefold division of the art of dealing

with them . . . . . . . . . 8 1

CONTENTS

XXXIV. Mistaken views as to the relation of lightning to other
presages. The former are of equal, not superior, value . . 82

XXXV. Fate cannot be changed by expiation and entreaty . . 83

XXXVI. " God is not a man" that he should change fate. What is

the use, then, of rites ?........ 84

XXXVII. Answer — Fate fixes some things only conditionally: the
alternative issues are determined by the conduct, active or
passive, of the worshipper ....... 84

XXXVIII. This action of his is likewise a part of fate. The sooth-
sayer, like the physician, is the minister of fate. Discussion of

free will deferred 85

XXXIX. Three classes or kinds of thunderbolts, as judged by their
indications, according to Caecina ...... 86

XL. These are kinds of prognostications rather than of bolts. The
different species of the latter are distinguished by their effects —
boring, splitting, burning. Fine distinctions of Latin terms . 87

XLI. A kind that stains or discolours. The Etruscan view of the

three kinds of bolt according to their division .... 88

XLI I. The Etruscans knew what they were about in attributing
certain motives and actions to Jupiter. Their theory was for the
benefit of the ignorant mass of humanity ..... 89

XLIII. "Which things are an allegory." An example is set to

earthly rulers to be merciful and consider well their judgments . 90

XLIV. Jove does not change his missiles ; but there are gradations in

the offence to be punished. That is the lesson . . . 91

XLV. By Jove the Etruscans meant, as we do, all that is greatest and

best — Fate, Providence, Nature, the Universe . . . . 91

XLVI. He is the source of the thunder's power, though he does not
superintend each stroke. Why he spares the guilty is another
affair, which will be discussed in another place .... 92

XLVII. An erroneous classification of thunderbolts according to time 92

XLVIII. It must be wrong, because the time is always limited. A
better basis of treatment is that of Attalus. Place, time, person,
etc., must all be looked into ....... 93

XLIX. Caecina's division, his names and their meanings ... 94

L. That of Attalus is much better, being based on the true significa-
tion ........... 95

LI. The signification of some does not affect, of some does not

reach, us .......... 95

LII. The force of lightning as seen in different materials, and at

different times in the same material (cf. xxxi.) 9^

LIII. Poisonous effects : may be followed up afterwards. Panegyric

on philosophy . . . . . . . . 97

LIV. Returns to Posidonius' (Aristotle's) opinion as to the cause of

thunder, an explosion of air . . . . . . . 98

LV. The collision of clouds may produce it. Air is the cause in this
instance also. Shooting stars are associated with thunder, but
this is the exception, not the rule 98

PHYSICAL SCIENCE

CHAP. PAGE

LVI. Heraclitus and Caecina think sheet lightning an intermittent

incipient fire. Change in the pronunciation of the Latin word . IOO

LVII. Lightning is probably due to the air turning into fire through
rarefaction of the clouds. It is naturally most frequent in
summer. Sheet and forked lightning differ in degree, not in kind IOO

LVIII. Reasons for rapidity of lightning and its obliquity . . 101

LIX. Every story should have a moral. Death cannot be prevented ;
why fear it ? It is cowardly and silly. Death by lightning is
rather an honour than otherwise. Besides, fear is futile . . 102

BOOK III

ON FORMS OF WATER
PREFACE

HAVING begun a mighty task in my old age I must make up for lost
time by hurrying on. The magnitude of it is actually an incentive
to effort. Such studies are far superior to the historian's task of
recording the deeds of the robbers and butchers of mankind. The
former raise us above the vicissitudes of fortune. " The principal
thing " is to have a pure heart and clean hands, to escape slavery
to self. The study of the universe exalts us to this . . .109

I. The cause of rivers and their varieties. Waters vary in amount at

different seasons, in temperature, in medicinal qualities . . 114

II. Varieties of taste, weight, colour, utility to health, consistency . 115

III. Gravitation or the force of air determines the flow of water. Surface

and spring water : they may be combined as in Lake Fucinus . 115

IV. Why is the sea not filled nor the earth drained dry by rivers ? . 1 16

V. Some hold that what flows into the sea returns by secret passages

cleansed of its salinity . . . . . . . . 1 1 6

VI. Some think rain supplies the rivers, and in proof cite the interior

of Africa as contrasted with Gaul and Germany . . . 117

VII. Objections to this argument. Rain does not penetrate more than
10 feet. If the earth is dry, it absorbs the rain ; if it is saturated,
the rain runs off. Again, rivers rise in rocks and mountains,
where what rain ever fell must have run ofT. Rich wells of
" living " water are found in the driest ground at depth. Fountains

well out at mountain tops . . . . . . .117

VIII. The interior of the earth is, according to some, a huge receptacle

of fresh water 118

IX. Others think the air which is contained within the earth being
prevented from circulating turns into water . . . . 119

X. But indeed the four elements are all interchangeable . . .120

XI. Though the supply of water is perennial, rivers and springs are
intermittent . . . . . . . . .121

XII. The abundance of water is no difficulty, since it is a fourth part

of the universe . . . . . . . . .123

CONTENTS xiii

CHAP. PACK

XIII. The relation of water to the other elements. Thales' silly
notion that the earth sails in water like a ship at sea . . . 124

XIV. The Egyptians divide each of the elements into male and
female 125

XV. The veins of the earth resemble those of the human body. There
are likewise the analogies of marrow, mucus, etc. , of injuries and

of bleeding, of parturition, perspiration, etc. . . . . 125

XVI. Intermittent fountains are an illustration of seasonal activity. The
great' vacant spaces of the earth and their tenants. Underground fish 1 28

XVII. The incredible wonders of nature are paralleled and even out-
done by the excesses of luxury . . . . . .129

XVIII. The extravagances of luxury, which make a wise man mad . 1 30

XIX. To return — a sudden eruption of water casts up fish, generally
poisonous. This points to the unfailing supply of subterranean
water 132

XX. Various tastes of water due to four causes ; qualities of water —
petrifying, soporific, intoxicating, fatal . . . . -133

XXI. The same pestilential influence as taints rivers is perceived in
caves : the noxious rivers flow from or through them . . 1 34

XXII. The Ocean and seas are coeval with the universe. So probably

are abnormal rivers like the Danube and the Nile . . . 135

XXIII. Rain and surface water must be added to subterranean . . 135

XXIV. The causes of hot springs 136

XXV. Poisonous rivers. Colouring power of others. Great specific
gravity of certain waters, its effects and cause . . . -137

XXVI. Intermittent rivers and springs. Means possessed by river,
fount, and sea of purifying themselves . . . . . 141

XXVII. Digression on the universal deluge which will destroy the
world. Nature is niggardly in creation, lavish in destruction.

Ovid is unequal in his treatment of this catastrophe . . . 143

XXVIII. Further imaginative pictures of what water can do by way
of destruction. Alternative methods of destroying the earth —
water and fire ......... 148

XXIX. Further possibilities of the same character. Distinctions of
seas, gulfs, etc., will all be obliterated ; nature and the works of

man will alike be overthrown . . . . . . .150

XXX. Nature shows by the chafing of the sea that she designs to
inundate the world. A deluge is part of the fore-ordained plan.
But there will be a new earth and a new race of men who will

not sin — for a time . . . . . . . .154

BOOK IV

CONTAINING A DISCUSSION OF SNOW, HAIL,
AND RAIN. [THE NILE]

PREFACE

THE dangers of flattery and its insidiousness. If you must have
praise, praise yourself. Lucilius has good cause : he must not,

PHYSICAL SCIENCE

CHAP. PAGE

however, think too much of himself because he is governor of that
historic province Sicily, which has ere now decided the fate of
generals and of empires . . . . . . . 159

I. Leaving Sicily and its marvels let us deal with the omitted part of

the last book, the Nile. There is no real analogy between it and

the Danube .......... 166

II. The course of the Nile ; its cataracts. The inundation of the

river. Its meaning to Egypt. Its denizens ; crocodiles and
dolphins in conflict. Causes of the overflow : melting of

snow ; Etesian Winds ; drying up of the springs through internal
heat of the earth in winter ; the attraction of the sun in Africa
draws water from the sea to fill up the gap caused by evaporation
[none of the accounts apparently accepted] . . . . 167

III. Origin of hail ; why it differs from snow . . . . .177

IV. Causes of snow in winter, hail in spring . . . . .179

V. It is said that the cooler air of the North (Scythia, etc.) is stirred

by the melting of the snow in spring and floats South, causing hail
instead of rain . . . . . . . . .180

VI. Hail, it is again alleged, is averted by sacrifice. If there is not a
victim handy you have merely to prick your finger ! . . . 1 8 1

VII. This belief in the power of blood was an ancient superstition . 182

VIII. Three causes why the air near the earth is warmest, and there-
fore produces snow rather than hail . . . . . . 1 82

IX. Democritus' view — dense bodies are heated most quickly, and
retain their heat longest . .. . . . . . 183

X. The air nearest the earth is denser than elsewhere . . , 1 84

XI. The tops of mountains, it is urged, should be warmer because
nearer the sun. The difference is wholly inappreciable if we
adopt the scale of the universe, the true one . . . .184

XII. The comparatively mild air near the earth causes snow, but not

hail 186

XIII. The despicable luxury of the effeminate Romans, who bought
snow, bathed in it, and must resort even to ice to cool the
unnatural feverish thirst born of their indulgence . . .186

BOOK V

TREATING OF WINDS AND MOVEMENT OF THE
ATMOSPHERE

I. DEFINITION of wind — air flowing in one direction. The air, like

the sea, is always moving, even when it is thought to be still ;
hence the necessity of the additional qualification — in one direction 193

II. Democritus says wind arises from a multitude of atoms in a small

space striving to get free, just like a crowd jostling each other . 194

CONTENTS

CHAP. PAGE

III. But wind does not thus depend on density ; cloudy or misty
weather does not necessarily produce wind, while wind is pro-
duced when the morning sun dissipates the air. Democritus is,
therefore, wrong . . . . . . . . -195

IV. Wind arises in two ways — from the interior of the earth by emis-
sion— like wind on the stomach ! — and from evaporation . . 196

V. The air has inherent power of movement, which is the chief cause

of wind, evaporation being a less powerful one. Water has the
power of moving and of imparting life to animals and plants . 197

VI. Fire even, the destroyer, sometimes generates life. Air in like
manner has a peculiar power of its own . . . . .197

VII. Breezes before dawn arise from rivers, etc. Do not last long . 198

VIII. The "gulf" wind (tyicoXirlas) : its origin and duration . . 198

IX. Connection of winds with seasons of the year and with the heat

and light of the sun. The sun does not directly cause the winds 200

X. Some cite the Etesian Winds as proof that he does. They blow in

summer when the snows melt and the moisture is carried South . 201

XI. But as to the effect of the sun, there is no analogy between the
Etesian Winds, which do not spring up till late in the day, and the
winds which rise at dawn and fall as the day advances . . 202

XII. Cloud squalls (twefoas). Their formation and combinations . 203

XIII. The breaking up of clouds produces wind. Air, in an effort to
get free, or heat, may produce this. Interruption of free passage
may produce a whirlwind, just as an obstacle in a river a whirl-
pool. Violent whirlwinds take fire (wprjffTrip). Some winds pro-
duce different ones. An analogy holds between air and drops of
moisture. A union of forces in air or in dew is necessary to give
impulse and produce a current. Air and wind are merely a matter

of degree .......... 204

XIV. Mode in which the subterranean winds are generated and make

their escape .......... 205

XV. Ancient miners of Philip's saw rivers and vast underground
reservoirs. It is some consolation to read such a story, which
shows greed is no new vice : the older generations were as reck-
less as we are in their quest for treasure better hid . . . 207

XVI. The four cardinal winds. The full list includes twelve. Their
names and directions ........ 208

XVII. The great circles of the earth which give twelve divisions, and
therefore prescribe the possible number of the winds . . . 2 Id

XVIII. The uses of wind and the illustration afforded of the wisdom
of Providence. The crops are dependent on it. So is commerce.
But we make the sea a highway to war and not to peace. We
go to seek for death, as if it were not always near. Xerxes,
Alexander, Crassus are warnings of the mischievous use of power
to cross the sea. Better, perhaps, the winds had never been
given at all. But the value of a natural gift must not be esti-
mated by the depraved use of it. Every gift, even sight and
speech, man has perverted in the same way . . . . 212

PHYSICAL SCIENCE

BOOK VI

TREATING OF EARTHQUAKES

CHAP. PAGE

I. EARTHQUAKE at Pompeii and the alarm it caused, many giving up

Campania as a residence altogether. If the solid earth fail, what
can be done ? Refuge from tempest and fire and thunderstorm
and war is possible, but not from earthquake. But ( I ) the whole
earth is subject to such movement : we cannot escape by changing
our ground — Tyre, Asia Minor, Achaia have all suffered. (2)
Death is the same in whatever form it come, the circumstances
matter not, a stone is all one with a mountain . . . .221

II. We cannot escape death. The hopeless find refuge in despair.

The knowledge of our frailty and mortality is our true solace.
Death must come, a death with circumstance is rather to be
preferred than otherwise. In an earthquake the earth shows
itself mortal as men are ..... ... 225

III. Our fears are due to ignorance. Through lack of a philosophic
view of the universe we consider phenomena strange which are
merely rare, e.g. eclipses. Fear may be removed by knowledge 228

IV. The study of such problems is the very worthiest ; it reveals
the secrets of nature, and is disinterested. But it is highly
profitable at the same time ....... 229

V. Various explanations of earthquakes have been suggested. The

earlier ones are crude, but not therefore to be despised. Every
subject develops as time goes on. Gratitude is due to the
investigators who first dared to question nature . . .230

VI. The cause of earthquakes is by some said to be water. Thales
of Miletus explains how this takes place, but he must be wrong :
the analogy of a ship sailing the ocean will not apply to the earth

(cp. III. xiii.) 231

VII. Water may be the cause, but may operate in quite different ways
from those supposed by Thales. Storms, etc., in subterranean

seas may cause earthquakes . . . . . . .233

VIII. There must be such subterranean water. The Tigris and
Arethusa prove it. Nero, the virtuous and the veracious, sent
two officers to investigate the sources of the Nile ; their account
confirms the assumption . . . . . . -235

IX. Fire is another alleged cause. It either bursts out through
opposing obstacles, as in the clouds (Anaxagoras), or burns away

the foundation and causes a subsidence at the spot . . . 236

X. Pieces of the earth falling in merely through the decay of age

may produce the effect without fire or any external influence.

This is Anaximenes' opinion ....... 237

XI. Fire is supposed by some to cause earthquakes by expanding the
vapour which it first causes to be given off from the subterranean
waters ........... 238

XII. Archelaus sets down the cause as air pressing up the earth's
internal wind which is already condensed to bursting point . 239

CONTENTS xvii

CHAP. PAGE

XIII. Aristotle and Theophrastus take evaporation to be the cause.
Strato, much in the same way, thinks that differences of internal
temperature are the cause ....... 240

XIV. By some it is thought that air is the cause, but that its operation,
along with water, is like that of blood and air in the vessels of
the body. The earth, it is assumed in this case, admits air,
which must find an exit. When it does so violently, the result

is an earthquake . 242

XV. The earth is porous, perforated at many points, and it is thus

that the air enters ......... 243

XVI. The earth is full of air, nourishing plants rooted in it, and exhaling
enough to feed the sun and the other heavenly bodies. Air
is the most movable of elements ; therefore the earth, if it is

full of air, must also have frequent movements .... 244

XVII. Obstruction of air, just as of water, causes greater impetuosity
when it escapes. Wind is frequently associated with earthquakes,

as at Chalcis 245

XVIII. Additional considerations to prove that the great cause of
earthquakes is air, i.e, wind ....... 247

XIX. Metrodorus of Chios compares the rumbling of an earthquake
to the resonance of the voice in a tub ; the underground caves
impart the sound ......... 248

XX. Various combinations of water and air supposed by Democritus

and Epicurus to co-operate to the production of earthquakes . 249

XXI. Air must be the cause. Different kinds of earthquakes . . 251

XXII. First species — shaking of the earth : its causes . . . 252

XXIII. Next comes the form of concussion caused by air. The great
Callisthenes, who braved the fury of Alexander and lost his life
for it, supports this view. Submarine effects of it are particu-
larly noticeable 253

XXIV. Different explanations may be given of the exact method in
which air acts . . . . . . . . .255

XXV. The striving of the air in subterranean caverns produces a con-
cussion or collapse in the earth above. The area of disturbance
is limited, never over 200 miles, as numerous instances prove.

The Pencils and Ladon were thus produced .... 256

XXVI. The nature of the soil composed of muddy accretions without
interstices is said to account for the exemption of Egypt from
earthquakes. So Delos in the sea has porous rocks which emit
the air easily. But the facts are wrong. There is abundant
proof that proximity to the sea is no safeguard against shock . 258

XXVII. A peculiarity of the Campanian earthquake, that it killed 600
sheep, is explained by the emission of pestilential vapour, by
which sheep, with their heads close to the ground, naturally were

most readily affected ........ 259

XXVIII. Noxious vapours are not, however, peculiar to earthquakes.
They are found in several parts of Italy habitually. Such, too,

is the origin of new diseases ....... 261

XXIX. Excessive fear drives people mad. Earthquakes split statues

and divide kingdoms, e.g. Sicily from Italy, Spain from Africa . 262

xviii PHYSICAL SCIENCE

CHAP. PAGE

XXX. The action of the air accounts for all the detailed phenomena,
splitting of walls, houses, towers, statues ; also for the prolonga-
tion of shocks for several days . . . . . .263

XXXI. A further proof that air is the agent is to be found in the
gradually diminishing violence of the successive shocks. Pheno-
mena in the pavement witnessed by a philosopher who was in

his bath .......... 264

XXXII. The moral. Life hangs on a thread ; why should one dread
the loss of it ? The greatness of the cause of death is no source
of terror. The hereafter is better and safer than earth. There
there is no fear of earthquake or thunderstorm, fire or flood.
Fear of death magnifies all human risks. Do not dread death,

long for it, and, if necessary, meet it half way .... 265

BOOK VII

TREATING OF COMETS

I. PHENOMENA, however wonderful, are not noted and admired

unless they are uncommon. The sun and moon and starry
heavens have no observers, but a Comet at once sets the
whole world agog. The nature of the stars is a sublime and like-
wise a profitable study . . . . . . . .271

II. The nature of Comets has not been hitherto fully investigated.

They are so rare that one wants a record of the movements of all

ever observed ......... 273

III. Democritus, Eudoxus, Conon, Epigenes, and Apollonius of
Myndus all fail to give any satisfactory account of the matter.

Nor had the Egyptians or Chaldaeans investigated them . . 274

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

V. But there are essential differences between whirlwind, which is

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

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

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

here either .......... 278

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

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

CONTENTS xix

CHAP. PAGE

X. The slowness and steadiness of the Comet could not be

accounted for on this assumption, nor its general behaviour and
shape 281

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

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

there are other objections ....... 284

XIII. Artemidorus thinks the firmament is solid and has openings
for stars. Comets are casual planets, or formed by conjunctions

of them. His account is a tissue of barefaced falsehoods . . 286

XIV. How would a solid firmament be supported ? No feasible
explanation can be offered. Besides, the number of stars is so
great — and they may all be " wanderers " if an indefinite
number is — that there must be innumerable conjunctions of them,

i.e. Comets. But, as a matter of fact, Comets are rare . . 287

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

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

it did ? 289

XVII. Apollonius of Myndus holds the Comet to be a true star
(planet) with an erratic course, visible only when it approaches

the lower part of its orbit. Different colours of Comets . . 290

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

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

XX. Most of the Stoics hold Comets to be evanescent, and attribute

them to friction of the air. Various phenomena are analogous . 292
XXL Their methods of accounting for varieties of orbits in Comets . 293

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

XXIII. Further arguments showing difference between fires and
Comets 295

XXIV. There may be many stars in the universe whose paths have
not been traced : Comets are such. No satisfactory explanation

has been given of the mind, but its existence is not doubted . 297

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

such matters ......... 298

PHYSICAL SCIENCE

XXVI. Reasons of apparent movements of Comets. The transparence

and shape accounted for ....... 299

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

XXVIII. Comets give prognostications, but not of immediate events

or weather .......... 302

XXIX. Denial of heaviness and slowness of Comets . . . 303

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

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

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

NOTES BY SIR A. GEIKIE ........ 309

TRANSLATOR'S NOTES ON "AiR," QUOTATIONS, AND GERCKE'S

READINGS .......... 344

INDEX 351

INTRODUCTION

SENECA
I. LIFE

Lucius ANNAEUS SENECA was the second son of Annaeus
Seneca (generally, but apparently without authority, called
Marcus Annaeus Seneca) of Corduba (Cordova) in Spain :
his mother was a Spanish lady named Helvia. The
elder Seneca was himself a man of note. He is known
as Seneca the Orator or Rhetorician, in contradistinction
to his more famous son, the Philosopher. His works that
have come down to us suggest by their titles, Controversiae
and Suasoriae, the rhetorical character of the contents.

Seneca had an elder brother, M. Annaeus Novatus,
and a younger one, L. Annaeus Mela (or Mella), father of
Lucan the poet (M. Annaeus Lucanus).1 The family
was thus a distinguished one. The poet Martial, himself
a Spaniard, speaks of " the house of learned Seneca thrice
to be numbered " (iv. 40. 2) : the allusion might with
equal appropriateness apply either to the three brothers
or to the three generations : Seneca the Elder, Seneca,
Lucan — father, son, grandson.

The eldest brother of the Senecan family, Novatus,
was adopted by a friend of the family, Junius Gallio, by
whose name he is known to history. Seneca on more
than one occasion makes reference to him in the Q.N.,
and always in the most laudatory terms. In iv. Pref. 9
et sqq., he pays a high tribute to his character, and a

1 Lucan, owing to the jealousy of Nero, was induced to join Piso's con-
spiracy in 65 and suffered the penalty. His heroic poem, the Pharsalia, though
in many respects crude, is a wonderful production for a man of twenty-six.
xxi

PHYSICAL SCIENCE

further proof of his admiration and affection is afforded
by his addressing to him his treatise on A Happy Life.
Gallic is of interest in another connection. He was
proconsul of Achaia during the period of the Apostle
Paul's activity there (Acts xviii.), and his conduct on the
occasion of a sectarian uproar at Corinth has attached
to his name a certain stigma which, perhaps, he does not
altogether deserve.

Seneca was born about the beginning of the Christian
era, probably in the year 3. By this time the language
and the arts of Rome had spread widely over the conquered
provinces, in many of which independent centres of culture
and literary activity had sprung up. While Rome as the
capital and heart of things continued to draw to herself all
that was best, or, at any rate, all that was most enterprising
and ambitious, her literary and even her political life was
largely recruited and maintained by supplies from external
sources, such as Spain, Gaul, and Africa.1

Seneca was brought by his father to Rome at an early
age,2 and there he was educated and spent practically his
whole life. His lot was cast in perilous times, those of
Caligula the madman (37-41), Claudius the imbecile
(41-54), Nero the monster (54-68). Seneca's early studies
were devoted to rhetoric. With such assiduity did he
prosecute them, and with such brilliant success were his
efforts at the bar crowned, that he speedily awakened the
jealousy of Caligula. The hint of danger was taken. By
his father's advice he abandoned law in the meantime and
devoted himself with equal ardour and enthusiasm to
philosophy. Among his philosophic tutors were Attalus,
a Stoic, and Sotion, a pupil of the Sextii, the decline
of whose school is lamented in the Q.N. (307). He
first embraced the Stoic doctrine, but finding the tenets

1 From Spain, besides the Senecas, Lucan and Martial, already mentioned,
came Columella, Pomponius Mela, Quintilian, etc. ; from Gaul came many
rhetoricians ; Africa sent so many of the same class that by Juvenal's time
(circ. 100) it could with propriety be designated " nursery of lawyers " (see
Teuffel, Hist, of Rom. Lit. vol. ii. 6).

2 His maternal aunt acted as nurse on the occasion : see Consol. ad
Helviam, xvii.

INTRODUCTION

and practices of this sect not sufficiently severe, he
adopted those of the Pythagoreans. His father, a man
with a good deal of worldly wisdom, saw the dangers
of extreme eccentricities of this kind, which implied a
covert condemnation of the whole world. He exhorted
his son to live more like other people ; he might other-
wise be mistaken for a Jew (i.e. a Christian) ! The
young barrister's difficulties were, however, ended for a
time by the death of Caligula (41). Seneca, who was
now thirty-eight, resumed his practice at the bar, and
opened a school for youths of noble birth, which was
largely attended. About this time also he obtained the
quaestorship, the duties of which introduced a young man
into public service and enabled him to obtain some
insight into the financial methods of the Empire.

His re-entry on public life was, however, destined to be
the prelude to another disaster. Indeed, all through his
subsequent life his interests were so involved with the
affairs of the rulers of the State that he must always stand
on slippery ground. The fact is, Seneca's abilities were
too great for his position. He was a man of the most
brilliant parts, "one of those ardent natures the virgin
soil of whose talent shows a luxurious richness un-
known to the harassed brains of an old civilisation "
(Cruttwell, Hist, of Rom. Liter, p. 378). In an age of abso-
lute and suspicious tyranny all eminence is obnoxious to the
ruling powers. It is a standing reproach to them, hence
a source of fear and alarm, a menace as they imagine, and
an incentive to disloyalty. During the very first year of
Claudius' reign Seneca was banished to Corsica, where the
next eight years find him. It was the outcome of a
Court intrigue. Messalina, wife of the Emperor, was
apparently jealous of the influence of Claudius' nieces,
Julia and Agrippina, whom he had just recalled from
banishment. Julia was again banished, and Seneca, on
the ground of an alleged improper intimacy with her, was
made to share her disgrace. His banishment was really a
blessing in disguise. He employed assiduously the period
of enforced leisure, devoting himself again to philosophy,

PHYSICAL SCIENCE

and returning to his first love, Stoicism. Here he per-
fected his study, and probably elaborated most of those
doctrines with which his writings abound. In Cruttwell's
words, he " struck out the mild and catholic form " of the
Stoic philosophy " which has made his teaching, with all
its imperfections, the purest and noblest of antiquity "
(pp. at. 379). To this period, too, belong some of what
may be called his earlier works, already showing remark-
able power.

His exile had been compassed by the notorious
Messalina, the third wife of Claudius. On her fall
Claudius married, as his fourth wife, his niece, the still
more notorious Agrippina,1 daughter of Germanicus
Caesar and sister of Caligula and of Julia. One of
Agrippina's first acts was to have Seneca recalled and
appointed tutor to the young Nero, her son by a former
marriage and now heir-apparent to the throne. This was
in 48, when Nero was but eleven years of age, and hence-
forth to the end of his life Seneca's fortunes are closely
associated with those of Nero, " a name to all succeeding
ages curst" To be tutor to a prince means much if the
pupil is docile. If he prove headstrong and at the same
time vicious, as Nero speedily did, the choice of the tutor
is an unenviable one, either to follow his pupil and palliate
his conduct, or else to resist at the risk of position and
influence and, it may be eventually, of life. With Seneca
at first all went well. The prince was amenable, the
tuition seemed to bear good fruit. The teacher was
faithful to his charge, and loyal to the prince's mother,
Agrippina, to whom he owed his office and influence.
Mother and son were still in accord. To the philosopher
there was no conflict of duty, no necessity for the choice
of one of two evils.

In 54 the vacillating Claudius was poisoned by
Agrippina, and Nero succeeded to the throne. For a time
the government was virtually in the hands of Seneca and
of Burrus, also an excellent man, commander of the

1 This lady must not be confounded with her mother, who bore the same

INTRODUCTION

praetorian guards. In these earlier years the young
Emperor gained a reputation for justice and moderation
which has thrown a halo round that golden quinquennium.
His tutor must in fairness receive a portion of the credit.
He seems to have been throughout imbued with an honest
desire to promote virtue and good government and to
check such vicious propensities as a youth with Nero's
antecedents was not unlikely to develop ; but whether the
means adopted were always unimpeachable seems more
open to question. Seneca's own interests were apparently
not neglected. In 50 he had been made praetor ; shortly
after he was raised to the consulship. Within the short
space of four years from his appointment as Nero's master
he had attained a position of commanding influence in
the State, and had amassed a colossal fortune (nearly
£3,000,000 it is said). The latter he attributed to the
unsolicited generosity of his master, but his enemies and
detractors had quite a different version of the matter.

For more than a decade after Nero's succession
Seneca's life is part of the history of the Roman Empire.
The philosopher had become, as it appeared, de facto king
and a new era seemed to have arisen on mankind.
Philosophers, it is true, have neither in ancient nor in
modern times shone in the sphere of action. The troubled
sea of practical politics is strewn with the wrecks of
philosophic reputations. Still, even before the age of
the Antonines, Seneca, if any man, might have been the
exception to prove the rule. He was a man of versatile
genius, he had had a practical training, he was a man of
affairs. The facts show that he had a true conception
of the necessities as well as of the duties of government.
But he was placed in an impossible situation. Agrippina
wished to rule her son, and her chosen means was
through his tutor. Nero, on the other hand, once he
had tasted the sweets of power, determined not to be ruled
by his mother, but to make her instrument his tool. The
condition of unstable equilibrium could not long continue.

The conflict came to a head through a disgraceful
intrigue of Nero's about the year 59. Seneca had to

PHYSICAL SCIENCE,

make his choice, and never was choice more difficult.
To Agrippina he owed everything — life, position, fortune,
his past belonged to her. But he saw that Nero was to
be the winner in the struggle ; his safety, his hopes, his
future lay with the ruling power. He may have felt that
expostulation was vain and resistance fruitless. He does
not appear to have attempted either. He decided to cast
in his lot with the Emperor. When Nero finally decided
to get rid of his mother, Seneca not only adhered to the
plan but consented to vilify her memory by composing
the letter to the Senate, in which the matricide sought to
justify his act. It was the great treason of his life. In a
critical situation he had chosen a wrong course, and it
cannot have been without a pang, a sense of moral
cowardice and tergiversation. He had sacrificed self-
respect, he had lost philosophic caste.

After the murder of his mother, Nero abandoned
himself to the wildest excesses and extravagances. The
philosopher had perforce to follow in his wake, and
humiliating enough he must have felt the part he
was obliged to play. Still, he and Burrus continued
to act as a sort of drag, conspiring with what of con-
science was left to Nero in checking his headlong
course. The beginning of the end, so far as Seneca was
concerned, came with the death in 63 of Burrus, his
constant friend and ally. Various indications now showed
that the tyrant was anxious to be freed from the last
remaining restraint. The philosopher felt his position was
insecure. The man who had murdered his mother, not
to mention his (step-)brother and his wife — two of his
other victims — was not likely to have great compunction
in ridding himself of his tutor. Seneca sought to anticipate
the storm by abandoning politics, retiring from Court,
and surrendering his estates. Nero refused the offer, and
expressed profusely his continued regard for his tutor ;
shortly afterwards he displayed the sincerity of his pro-
fessions by an insidious attempt to poison him ! The
philosopher then renounced all his state, adopted a
voluntary poverty, and by putting into practice his

INTRODUCTION

professed tenets of the simple life endeavoured to avoid a
repetition of the risk at least of poison. His diet was
herbs, his drink, water from the fountain. But it was
only a matter of time now. The occasion for which the
Emperor was on the watch came in 65. In that year
Piso's conspiracy was formed against the Emperor's life,
and Seneca was accused, falsely so far as we can judge,
of complicity. He was ordered to prepare for death,
which, according to the custom of the day, allowed the
victim the choice of means, and was usually a voluntary
opening of the veins in order to bleed to death. Tacitus
has with characteristic power and pathos depicted the
scene (Annals^ xv. 61-4^). No act of his life, it would
seem, became Seneca better than the leaving of it
His death was worthy of a philosopher and a Stoic.
With the utmost calmness, amid a throng of mourning,
sympathising friends, he faced his fate, and yet with
the studied pose of a man who had conned the part.
The age was one of posturing. Men were always under
the eye of the informer and the spy, and learnt to act
their part accordingly. The " meditation of death " must
often have occupied the philosopher's latter days. He was
a second Socrates consigned to an unjust end ; the last
scene was enacted with all the dignity, composure, and
even cheerfulness of his great prototype. The cock due
to Aesculapius has a parallel more worthy of the occasion
in the libation to Jupiter the Liberator. The supreme act
atoned for many weaknesses and failures.

Though Seneca was not without many detractors,1 his
worth as a man is attested by many proofs. His young
wife Paulina desired to share his fate, and opened her
veins along with her husband. By Nero's orders she
was saved, but she continued to the end of her life to
bear in her unnatural pallor the marks of her devotion.
Tacitus, writing at a distance of thirty or forty years,
describes the character of Seneca in terms of commendation
and esteem. No doubt the historian had himself borne

1 Dio Cassius is often very caustic in his criticisms, but even he recognises
Seneca's sterling merit and services to the state.

PHYSICAL SCIENCE

the yoke of the savage Domitian, and knew what life under
a tyrant meant. But withal he was too acute an observer
and too impartial a critic to be blinded by any mere
sentimental sympathy. He understood and appreciated
Seneca, to whose genuine worth his testimony is the most
enduring tribute.

The age of Seneca, whose " life almost coincides with
the Julio-Claudian tyranny," has been made to re-live for
us in Professor Dill's Roman Society from Nero to Marcus
Aurelius, which ought to be studied by those who desire
to understand more of Seneca as statesman, philosopher,
and man.1 In addition to a short account and criticism of
the Quaestiones Naturales (pp. 300 et sqg.\ the chapter
(Book III. ch. i. pp. 289-333) on "The Philosophic Director"
is particularly illuminating. The following tribute from
it may fittingly close our brief sketch : —

"The man who approaches Seneca thinking only of
scandals gleaned from Tacitus and Dio Cassius, and
frozen by a criticism which cannot feel the power of
genius, spiritual imagination, and a profound moral experi-
ence, behind a rhetoric sometimes forced and extravagant,
had better leave him alone. The Christianity of the
twentieth century might well hail with delight the advent
of such a preacher, and would certainly forget all the
accusations of prurient gossip in the accession of an
immense and fascinating spiritual force. The man with
any historical imagination must be struck with amazement
that such spiritual detachment, such lofty moral ideals, so
pure an enthusiasm for the salvation of souls, should
emerge from a palace reeking with all the crimes of the
haunted races of Greek legend" (pp. cit. p. 295).

II. WRITINGS

Seneca was a voluminous writer. Most of his works
partake more or less of a philosophical character. In a
class by themselves may be placed the ten tragedies,

1 Mr. Henderson's The Life and Principate of the Emperor Nero should
also be studied.

INTRODUCTION

together with some verses, attributed to him. The titles,
Medea, Hercules Furens, Hippolytus^ Agamemnon, etc.,
suggest the Greek subjects as well as the plays of the
same names by Euripides and Aeschylus. The treatment
of the themes is all Seneca's own. Moral maxims
abound ; the plays are homiletic and were never designed
to be acted.

One of the plays is of special interest as dealing with
current topics. This is the Octavia, whose chief character
is Nero's wife of that name, exiled by him in order to
make room for the licentious Poppaea Sabina. Seneca
himself is introduced as one of the characters, deploring
the vices of the age and the unhappiness of those set in
high position. If the play is genuine, which has been
doubted on the ground of references in it that seem to
apply to Nero's death, it goes to prove that Seneca used
very plain language toward his master and pupil. In
any case, it shows what the relation of Seneca to Nero
was generally supposed to be. Tacitus (xv. 61) repre-
sents Seneca as telling Nero by messenger that the latter
has had more frequent experience of his independence
than of his servility, and the Octavia is fair comment upon
his statement.

Here is a specimen of the dialogue : —

Nero. Fortune has put everything in my power.

Seneca. Distrust her favours : she is a fickle goddess.

N. To fail to see all that one may do, betrays the coward.

S. The credit lies in doing not what one may, but what one ought.

N. The crowd tramples on a feeble prince.

61. They will crush a hated. one :

and so forth. Seneca's last remark may be a prophecy —
some would say after the event. The play contains other
allusions which suggest some of the actual details of
Nero's end.

The prose works include :

(a) Philosophical Essays such as Anger, Clemency,
Benefits, Calmness of Mind, A Happy Life, The Shortness
of Life, Providence, or Why Providence allows troubles to

xxx PHYSICAL SCIENCE

afflict the Just, The Constancy of the Sage, The Leisure of
the Sage.

(b) Letters, or rather Treatises, of Condolence, the so-
called Consolations, addressed respectively to his Mother
Helvia ; to Marcia, the daughter of Cordus, on the death
of her son ; to Polybius, the powerful freedman of Claudius,
on the loss of his brother.

(c) Letters to Lucilius, a hundred and twenty-four in
number.

(d) Apocolocyntosis — a lampoon on the deceased
Emperor Claudius. On such occasions deification (apothe-
osis) was accorded to the late ruler, and he was received
into the number of the gods. This skit describes the
reception of Claudius in heaven and his expulsion thence
to the lower regions, with his trial and sentence there.
Pumpkinification is the nearest English translation of the
title.1

(e) Quaestiones Naturales.

(/) Works no longer extant, the only one of them
that concerns us being that on Earthquakes, referred to as
a work of his youth in Q.N. 230.

(g) A spurious work, as is now on all hands conceded,
is the correspondence between Seneca and St. Paul. In
his opposition to popular beliefs and superstitions, and in
the purity of his moral tenets, Seneca approached some of
the Christian doctrines, and it was no improbable supposi-
tion that at the Court of Nero he might have became
acquainted with the Apostle of the Gentiles.2 But the
assumption of a correspondence of this kind is another
affair. Its genuineness was believed from the time of
Jerome (400) till the sixteenth century.

Seneca is generally considered to appear at his best
in the Consolation to his Mother Helvia and in the Epistles
to Lucilius, which are therefore usually ranked as amongst
his finest works. The latter work, which from the outset

1 One would have expected that Claudius' fate would be to be enrolled
among — the Pumpkins. But the piece as we have it contains no allusion to
this.

2 See Mr. Henderson's Life and Principate of Nero, 286-7, and Mr.
Glover's The Conflict of Religions in the Early Roman Empire, 1 49.

INTRODUCTION

was designed for publication, is not an ordinary corre-
spondence on the current affairs and interests of everyday
life like Cicero's Letters, but is philosophic in character ;
it covers a wide range of moral discussion and reflec-
tion, and is full of admirable maxims. Many of its
sentiments have become commonplaces ; their almost
hackneyed character detracts perhaps somewhat from our
appreciation of their intrinsic merit. On the other hand,
the spitefulness of the Apocolocyntosis, the servility of the
Consolation to Polybius, and the flattery of the Clemency,
which was addressed to Nero, show the reverse of Seneca's
character. Of the characteristics of his style, however,
and of his position in Roman literature — one of command-
ing importance — this is not the place to speak. His
works reflect truly enough both the iron and the miry
clay which entered into his mental and moral composition.

III. "QUAESTIONES NATURALES "

This work stands in a category by itself. It raises a
number of difficult problems, in which every reader of it,
whether classical scholar or not, is interested.

The historical title, Natural Questions, is convenient,
though, without explanation, a little misleading. The
nearest rendering of the Latin form Quaestiones Naturales
is Physical Inquiries, or Investigations in the Domain of
Physics, or, as in the title, what we should now call
Physical Science. The terms Physics and Science had
a very different connotation in that age and in ours.
Plutarch, almost a younger contemporary of Seneca,
gravely discusses in a work with a similar title such
questions as Why shepherds give their sheep salt, Why
horses' hair is superior to mares' for casting-lines, and
even, Why a dog runs after a stone rather than after the
person who threw it ! The extent of such a title is
determined pretty much by the range of topics an author
decides to include. In Seneca's case, as it happens,

PHYSICAL SCIENCE

the branches chiefly dealt with are Astronomy and
Meteorology, together with certain portions of what
may be designated as Physical Geography including
Seismology.

Science was in that day synonymous with Philosophy,
or at any rate Philosophy embraced all that could claim
to be Science. Learning was homogeneous ; its sub-
divisions had not yet been separated or differentiated.

The treatise was addressed in a quasi-epistolary form
to Lucilius Junior, procurator l of Sicily. Most of our
knowledge of him is derived from Seneca, who, besides
the Q.N., addressed to him his Epistles and his tract on
Providence. Lucilius seems to have been a prottgt of
Seneca, and rising from the ranks under his fostering care
and guidance, not only to have attained a position of
influence, but also to have achieved literary distinction.
His philosophical predilections were toward Epicureanism,
but he was a man of high principle and character, though
not exempt from dangerous temptations at various points in
his career. His public labours had associated him with Sicily,
and the themes of his writings, chiefly poems as it would
appear, had been drawn from the same quarter. He is,
not without probability, supposed to have been the author
of the anonymous didactic poem Aetna, for long attri-
buted to Virgil, a work which presents many interesting
parallelisms to the Q.N. both in its science and its
philosophy. Seneca's Epistle Ixxix. contains a special
charge to Lucilius, who was at the time making a circuit
of his province, to report the facts concerning Charybdis —
Seneca knew all there was to know about Scylla — and to
investigate in detail the present condition of Aetna. The
letter goes on to banter Lucilius upon the inclusion of
Aetna in the poem on which he was engaged — no doubt
the work referred to in Q.N. 114, 142 ; cf. 167. The whole
question is discussed with full knowledge by Professor
Robinson Ellis in the Introduction (xxxvi-xlviii) to his

1 The procurator was in this case practically governor. In some instances
he was the representative of a chief governor (praeses] to whom he was
subject, e.g. Pontius Pilate was procurator of Judaea under the Governor of
Syria.

INTRODUCTION

edition of the Aetna, to which reference should be made.
For other allusions to Lucilius in Seneca see, besides the
Q.N., Epistles xix. xxvi. xxxiv. etc.

The Q.N. was composed probably about the year 63
or 64. We might content ourselves with the statement
of the fact, did not the circumstances of composition
throw light upon difficulties of arrangement and sequence
which can scarcely be passed unnoticed. The evidence
on which we have to rely is chiefly internal. The exact
date of Lucilius' procuratorship in Sicily (159) is unknown,
but the consulship of Regulus and Virginius, which
witnessed the Campanian earthquake (221), fell in 63,
that is, some two years before Seneca's death. The
allusions in the Preface to Book III. (109) are still
more direct and convincing. The writer was drawing
near his end, pressed hard on the rear by old age, with
every necessity and incentive to hurry on the completion
of his task.

On the other hand, the mission despatched by Nero
to the sources of the Nile (235-6) would naturally point
to an earlier date during the more promising years of his
reign — unless indeed, as is by no means improbable, the
complimentary reference to the emperor's virtues be a
piece of adulation. A similar reference recurs in con-
nection with the comet in Nero's reign (290), the date of
which must (after Tacitus) be assigned to the year 61.

The Elder Pliny, writing in 77, about a dozen years
after Seneca's death, adds to each Book of his Natural
History an exhaustive list of the authorities, native and
foreign, that he had used. Book II. deals with many of
the subjects of the Q.N., of which it is in some places an
expansion, but in most little more than an epitome.1
And yet no mention of Seneca occurs in the list of

1 See particularly Pliny's treatment of Comets (ii. xxii. ), Winds (xliv.-l.),
Lightning (liii.), Floating Islands (xcvi.). But most striking of all is the
reproduction (Ixiii.) of Seneca's remark (208 end of c. xv.), "If any nether
gods existed, they would have been dug up long ere this in the mines sunk
by our avarice and luxury." The two authors had hit upon the same thought,
and Seneca had happened to use it first. Or it may have been a current
witticism in an age of unbelief.

PHYSICAL SCIENCE

authorities attached, which seems strange if the work had
then been given to the world.1

We read in the Sixth Book of the Q.N. (230) that the
author had previously, when a young man, composed a work
upon Earthquakes. This, taken in connection with what
precedes, and with what we know of the author's character
and interests, affords some ground for the conjecture that
he may have worked intermittently at the subject at
various periods of life. But no doubt the arrangement of
the materials and the completion of the work belong to
his latter years. He had by this time lost his hold upon
Nero, and had practically retired from political activity.
His trust in princes had been found misplaced. He was
disappointed if not embittered. The discussion of public
affairs was precluded. It was dangerous even to let one's
thoughts rest upon them. But there were consolations
for political disappointment and inactivity. Recourse
might be made to the contemplation of those great works
and workings of Nature which are exempt from the
caprices of human passion. The study of Nature was
equally fitted to humble and to console ; to it Seneca
betook himself for refuge.2

The Q.N. may, thus, have been composed at different
dates, materials for it being gathered at various times as
opportunity offered. But the final arrangement and
systematisation belong to the last years of the author's
life, about the years 63 or 64. The publication may not
have taken place until some time subsequently, and may
have been carried out by Lucilius, who was Seneca's literary
executor. So much is certain, that the work as we have
it is not the work as it left the author's hand.

Much time and ingenuity have been bestowed on

1 Seneca's name does occur in the lists attached to Books VI. IX. and
XXXVI. ; the first is geographical, dealing with Asia and Africa, the second
has for subject fishes and aquatic life in general, while the third deals with
the natural history of stones.

2 " The Stoics affected to despise physical studies, or at any rate to postpone
them to morals. Seneca shared this edifying but far from scientific persuasion.
But after his final withdrawal from court, as the wonders of nature forced
themselves on his notice, he reconsidered his old prejudice, and entered with
ardour on the contemplation of physical phenomena" (Cruttwell, op. cit. 381).

INTRODUCTION

attempts to restore the Q.N. to what may be supposed
to have been its original form. The most casual reading
of it as it stands, shows that it is full of inequalities. If
the clue could only be recovered, much of its difficulty
and obscurity would disappear. As it is, it abounds in
abrupt transitions, interruptions of the logical sequence,
repetitions, excrescences, and even irrelevancies and incon-
sistencies, which it can hardly be supposed that an author
would have allowed to remain in a treatise prepared for
publication.

One or two considerations derived from the present
arrangement will serve to throw light upon this point
In the first place, Book IV., as we have it, is evidently
composite. Between Chaps. II. and III. there is a deep
hiatus. In the former chapter the discussion of the Nile
is cut short, and the author's own view is not even
indicated, much less established ; while the latter opens
so abruptly as at least to suggest that it may have origin-
ally been preceded by something with which it stood in
organic sequence.

Again, the several Books do not conform to the
author's division of the subject as set forth in the opening
of Book II. (51), but follow — or precede — one another
anyhow.

Then, three of the Books (I. III. IV.) have a formal
Preface, while the others have not, though in them, too,
with the exception of the Sixth, the opening chapter is
introductory in character.

Any attempt to restore a more intelligible order must
depend for its success on the extent to which we may
assume Seneca to have been a methodiser. In Book II. i.,
he certainly states very distinctly the divisions of his sub-
ject— (a) things in the heavens, (£) things between heaven
and earth, (c) things on the earth. But it by no means
follows that he himself maintained this order of treatment,
or that he always exhausted one subject before passing
on to the next. The division evidently enumerates the
subjects in order of dignity or worth, and may have little,
if any, relation to the order of their discussion ; in fact, in

PHYSICAL SCIENCE

Book II. he goes on immediately to deal with meteorology,
his second and not his first topic.

Bernhardt (Die Anschauung des Seneca vom Universum,
p. 7) frankly accepts the traditional order of the Books,
and finds its explanation in the distinction between
phenomena and elements. The first three Books deal
with the phenomena of heaven, air, earth, respectively ;
the last four respectively with the elements — water,
air, earth, fire. This is ingenious, if not altogether
convincing.

The most recent editor, Professor Gercke, divides Book
IV. into its two constituents, IV. (a) = IV. Pref.-ii., IV.
(£) = IV. iii.-xiii., and arranges the Books in ascending
scale thus: Earth III. IV. («) ; Air IV. (£), II. V. VI. ;
Heaven VII. I. There seems great probability, almost
amounting to certainty, that there were originally eight
Books, as he supposes. But a consistent and fairly
natural order might perhaps be restored with less violence
to the accepted form than his scheme involves. Books
III. and IV. (a) seem to have been misplaced or transposed,
being placed after Book II. instead of after Book VI., where
they originally stood ; Book IV. (a) had somehow got muti-
lated, which the more easily led to the confusion. Book IV.
(#) also suffered somewhat in the process. Thus the original
order may have been I. II. IV. (b\ V. VI. ; III. IV. (a) ;
VII. ; the first five Books deal with Meteorology, including
Seismology (air), the next two with Physical Geography
(earth), the last Book with Astronomy (heaven). A single
change of the order is thus all that is required ; but, of
course, the regrettable gap after IV. (a) remains.

Even with this rearrangement the sequence leaves
something to be desired. But it must be borne in mind
that the author makes a claim to philosophic liberty (178),
and that in no case can the rules of modern requirement
be applied to him.

Of course, if the assumption of methodical arrangement
be unfounded, and the author composed just as the humour
took him, the existing order may be all right : it is as
good as any other fortuitous collocation. Some have

INTRO D UCTION

supposed that the work was left unfinished at the author's
death, but of this we have no proof.

The language of the Preface to Book III. has been
taken by some to imply that this was the opening of the
whole work. Whether this is so must remain to some
extent matter of opinion. It may, however, be pointed
out (a) that the claim of the Preface to Book I. seems at
least equally strong, (b} that the language of § 4 of the
Preface to Book III. (i 10), "how much is unaccomplished
of my plan, though not of my life," seems inapplicable
to a work that was not begun or merely beginning.
There was a remnant of the work and a remnant of life,
but they were disproportionate, the one large, the other
small. This was a reminder to hurry on to completion
a work with which, ex hypothesi, some progress had already
been made.

When all has been said, we must, for practical purposes,
accept the book as it has been handed down to us and
make what we can of it The difficulties are not exhausted
even when the pristine order is restored. What is true of
the work as a whole is true of it also in detail. The text
is full of uncertainties and corruptions. The work was
popular and was frequently copied, and this naturally
gave rise to variations, which, being improved upon by
succeeding generations of copyists, in course of time
rendered the text in many places very obscure if not
unmeaning. The nature of the subject matter, frequently
little understood, no doubt facilitated and hastened the
process of corruption. Hence the translator has at every
turn to decide first what, and then how, he shall translate.1

An added difficulty is the form of address to Lucilius.
The adoption of the epistolary style, whatever its other
advantages, has not, it must be admitted, conduced
to the lucidity of the argument. Science does not
readily lend itself to exposition by dialogue, and the

1 Gercke says (Preface, xlvi) that the traditional text of the Q.N. is
utterly corrupt and still requires the united efforts of many earnest scholars
for its restoration. He writes as recently as two years ago (1907), and has
himself probably made the most considerable contribution of all the editors to
the correction of the text ; but he modestly calls himself only a pioneer.

PHYSICAL SCIENCE

trouble is aggravated when, in addition to the corre-
spondent, an imaginary opponent is from time to time
introduced and indifferently addressed in the second
person, or referred to in the third. To make matters
still worse, the author frequently conceals himself behind
the mask of one or other of the disputants, irrespective
of pronouns. Finally, he employs " we " sometimes of
himself and his correspondent, sometimes of his philosophic
sect, the Stoics, sometimes of his nation, the Romans,
sometimes of his kind, man in general !

IV. SENECA'S METHOD OF TREATMENT OF
SUBJECT

In order to appreciate Seneca's treatment of his subject
we must understand something of his philosophical tenets.
He was in the main a Stoic, but with such a strong
tendency toward independence that he may be considered
an Eclectic. The Stoics, whether or not they originated,
at any rate recognised and adopted the threefold division
of philosophy — Physics, Ethics, Logic * — which was origin-
ated among the Greeks and handed down by them to
the Romans, who were in this department their pupils.
Seneca is typical of the Stoics in regarding Ethics as of
supreme importance. On Logic he did not apparently
set any great store, though he must have been a diligent
student of the cognate branch, Rhetoric. Physics, as we
have seen, did not claim much attention from him in early
life ; only as he approached the mature age of threescore
did his study of it become more detailed and systematic.
No clear line of demarcation existed in his mind, or for
the matter of that in his age, between philosophy and

1 See Professor Davidson's The Stoic Creed, p. 42, where it is pointed out
that each of these may be subdivided so as to bring the number up to six —
Physics and Theology, Ethics and Politics, Logic and Rhetoric. See also
Seneca, Epist. Ixxxix., where the division is discussed. For further infor-
mation on the subject, the article on the Stoics in the Encyclopaedia Britannica
and any of the histories of philosophy, e.g. Erdmann or Zeller, may be
consulted.

INTRODUCTION

science. Yet there is considerable internal evidence in
the Q.N. that his pursuit of such studies was in part an
outcome of the true scientific spirit, and that he possessed
in no ordinary degree the scientific imagination. Still,
when all due allowance is made for this, it remains true
that Seneca was moralist first and physicist or scientist
afterwards. Physics led to theology,1 and had thus a
direct bearing on man's destiny and fate. Had there been
no Ethics, whose interests were involved in a knowledge
of the universe, its parts, its function, and its author, the
impelling motive for the study of Physics would have been
removed. Possibly when his political career was closed
by the death of Burrus in 63, Seneca might in any case
have devoted some of his leisure to a subject which
offered such opportunities of exalted contemplation. But
it was his ethical aims that added the chief zest to the
pursuit.2 As the various departments of knowledge had
not assumed definite divergent forms, there was nothing
incongruous to his mind in the mixture, or as he might
have regarded it, the union, of what to us seem so different
from one another as Physics and Ethics. The facts of
nature had, in his view, to be brought into connection with
the lessons that may be derived from them. In so many
words he tells us (102) that every study must have a
moral attached to it, or to put it otherwise, that physical
phenomena must be made the occasion for driving home
some general truth, establishing some ethical position,
clinching an argument, reprobating a vice. The conclusion
of each Book of the Q.N. contains the practical application
of the lessons to be derived .from its subject : there are not
infrequent digressions, too, for the same or a cognate
purpose. The author's moral zeal sometimes ran off with
him, and he felt constrained to break off for the time his
discussion of scientific truths and to assume the role of
the moralist and reformer.3

1 Cf. Professor Burner's Early Greek Philosophy for illustration of this in
earlier times.

2 Cf. footnote 2 to p. xxxiv.

3 The method was not obsolete for many centuries, even if it is yet wholly
dead. On more than one occasion the study of Natural History has been

4

PHYSICAL SCIENCE

The reader of the Q.N. need not, therefore, regard as
matter of surprise this curious medley of science and
morality, which is of the very essence of the author's
principles and purpose. Seneca performs this part of his
task with evident relish. He is always ready to improve
the occasion, and will even go out of his way to find it.
His censure of vice, his denunciation of luxury and self-
indulgence, his castigation of immorality, seem to afford
him a kind of morbid satisfaction. Even a note of
insincerity may sometimes be suspected. He is rather too
ready to display his own acquaintance with all the refine-
ments of the vices of " good society " : perhaps it was
the fault of his age to gloat over unsavoury details that a
moralist would now be more anxious to conceal than to
reveal.1

With Seneca as moralist, however, we are not here
directly concerned. But what attitude are we to assume
toward his Science? It need scarcely be said that of
Science in the twentieth century sense, the first century
of our era knew very little. Its greatest weakness was
that it possessed practically no means of interrogating
nature save those afforded by the human senses. The
sundial was known, but the thermometer, the barometer,
the telescope, and even the microscope, had still to be
invented. Experiment except in the most rudimentary
form was impossible. Observation was the only method
available, and it lost much of its value from the necessary
looseness and inaccuracy attaching to it. Seneca was
fully alive to the necessity of procuring correct data. He
records his own observation when digging among his
vines (117) ; he had visited the Sabine country to see a
floating island (139); he had evidently watched closely
rainbow, lightning, meteors, comets, etc., etc. He laid

advocated on account of the abundance of figures of speech that may be drawn
from it ! Erasmus esteemed it because of the light it threw on the classics ;
his insensibility to the wonders of natural forces and processes provoked
Luther's remark that " Erasmus looks upon external objects as cows look
upon a new gate. "

1 " There are pictures of voluptuous ease and jaded satiety which may be
the work of a keen sympathetic observation, but which may also be the
expression of repentant memory" (Dill, op. cit. p. 298).

INTRODUCTION xli

friends like Lucilius under contribution, and he insists on
the necessity for keeping records of observation, especially
when the phenomenon is comparatively rare, as a Comet
(274). Besides, he draws not only upon the history of
his country, but also upon the learning of other nations —
Greeks, Babylonians, and Egyptians — records which for the
most part are no longer extant. The Q.N. thus embodies
many out-of-the-way facts which otherwise would be
unknown to us. Accuracy is nearly always a relative
term : approximate accuracy is the most we can look for
in that age. Seneca's contribution of data is curious,
interesting, and valuable.

Again, in arguing from facts, or supposed facts, Seneca
is entitled to credit for his method if not always for his
results. A great merit is that he endeavours to account
for the phenomena observed, he habitually raises the
causal issue, and he is not satisfied until he has passed in
review all the considerations involved in the observation
or problem. He is scrupulous in always giving the other
side a hearing, and in discussing views with which he
disagrees, even though only to reject them. On the
negative side he is generally fairly convincing, and succeeds
in showing the fallacies involved in a proposition. But
on the constructive side he is many times ingeniously
perverse, curiously blind to the inadequacy of the theories
which he himself advances, and which he would readily
have confuted in an opponent. Sometimes he adopts an
error already current, as old as Aristotle or older ; some-
times he advances a fresh one of his own. But even his
errors are instructive, and represent a phase of progress.
The line of progress is zigzag. Only after errors have
been exhausted does the truth emerge and advance become
possible.

The amenities of ancient science seem to have been
somewhat scanty. A mistake, a false inference, an
erroneous view, is met with the lie direct. The moral
stigma of falsehood is, at any rate in certain instances,
attached to such a deviation from fact. Nor is this all.
The whole character must be bad if a man has " lied."

xlii PHYSICAL SCIENCE

The authors, whom Seneca calls chroniclers, and particu-
larly Epigenes, are in one passage quite fiercely attacked
(289). In justice to Seneca it must be said that he is
hardly more polite toward himself. The words on p. 154,
§ 2, rendered, " I can give my own word, etc.," read liter-
ally, " I'm a liar if water does not meet us, etc." Perhaps,
therefore, it is only a manner of speaking. In the early
days of public education in Britain a Government report
recorded as a proof of moral progress the substitution in
some parts of the country of " I beg your pardon " for
" You're a liar ! " The child seems to have here re-lived
the history of the race.

Seneca had a wide outlook, too, and a splendid scien-
tific faith. With prophetic eye he sees the day when an
astronomer will arise to demonstrate the nature and orbit
of Comets1 (299) ; he is content to let posterity have a
share of the credit ! Nor is his humility less than his
confidence. His lessons may still usefully be taken
home ; we imagine we have pierced to nature's inmost
sanctum, yet we are still loitering round her outer court
(306); let us not despise the day of small things, the investi-
gation of nature's marvels requires generations of workers
and ages of work ; there will come a day when all will
be revealed, when posterity will smile at our feeble and
clumsy efforts and wonder how we missed such obvious
truths (298). The ancients must be treated leniently ; it
was a large contribution to discovery to have conceived
the hope of its possibility (231). Seneca maintained and
promoted this belief in ultimate success. He displays
throughout the same alert, buoyant, enthusiastic confid-
ence, together with patient, reverent search for truth in
nature and truth about God.

Seneca nowhere gives us a reasoned connected exposi-
tion of the views entertained by him regarding the Universe
as a whole or the relation of its parts. Only " by parcels "
and inference can we glean them from scattered remarks
and comments that he makes in the course of his work.

1 The fulfilment, or at least the beginning of the fulfilment, of this predic-
tion may be dated from Newton in 1680.

INTRODUCTION xliii

In Physics even more than in Ethics he was an Eclectic ;
he criticises freely, and occasionally rejects entirely, the
opinions of his own school, the Stoics, at one point going
so far as to call them silly (181, cf. 295). He claims
authority, too, for his own research, and asserts the right to
hypothesise for himself: he is hopeful, if not certain, of
discovery (304). He frequently quotes rival opinions
without indicating his own. He is familiar with conflict-
ing theories which he does not attempt, or fails in his
attempt, to harmonise. And in the end one is tempted
to ask whether he himself had reached any consistent
comprehensive cosmical scheme. There is much that is
quaint and interesting and ingenious, but it seems doubt-
ful whether an attempt to construct from the Q.N. a
complete cosmology would in the end repay the labour.
The scheme might prove self-contradictory ; it would in
any case be full of error, and there would in no case be
the assurance that it was all Seneca's own. This seems
sufficient reason for declining the task. If one care to
pursue it further, helpful information may be obtained
from Bernhardt's brochure (Die Anschauung, etc.} already
referred to, while a discussion of the whole subject will
be found in Crousle's Thesis, written in Latin, De L,
Annaei Senecae Nat. Quaest., which for fulness and fair-
ness leaves nothing to be desired.1 In the Commentary
and Notes at the end of the volume Seneca's scientific
opinions and methods are discussed by Sir Archibald
Geikie.

V. SOME OF SENECA'S PREDECESSORS AND
CONTEMPORARIES

The history of ancient Science is a very tangled and
abstruse subject, a portion of the history of ancient

1 Ideler's Mcteorologia veterum Graecorum et Romanorum, which forms the
Prolegomena to his edition of Aristotle's Meteorology, but is printed as a
separate volume, also contains much curious information on this recondite
subject.

xliv PHYSICAL SCIENCE

Philosophy, which lies as much outside the scope of the
present work as beyond the powers of the writer. Still,
Seneca cannot be altogether detached from what pre-
ceded him. In order to throw light upon his work, it
may be permissible to pass in rapid review a few of the
chief sources from which he drew. Our starting-point
may be Aristotle.

Aristotle is with good reason named " the master of
those who know " (Dante, H. iv.). He may be said to
have summed up the knowledge of the ancient world,
at least as far as Greece is concerned, on all subjects. If
not the founder of Science any more than of Philosophy,
he recapitulated so fully all that went before that he
became the fountain-head and source from which all
succeeding workers mainly drew. He systematised the
existing materials, adding his own criticisms and observa-
tions, and illuminating the whole with the strong light of
his unrivalled powers. He drew upon many authorities
whose works are now lost, the leading names among
them being familiar from the Q.N. — Thales, Anaximander,
Pythagoras, and the rest. The extent and variety of
the material may, perhaps, best be understood from a
work like Professor Burnet's Early Greek Philosophy, to
which reference should be made. A reasoned con-
secutive account will there be found of the individual
contributions made to philosophy (including science) by
the early Greek thinkers. Long before Aristotle's time
numerous physical theories had been propounded, and
had been supported by their authors with great acuteness
of argument ; hardly any question had been left unasked
that related to matter, motion, or mind. " We may smile,
if we please, at the strange medley of childish fancy and
true scientific insight. . . . But we shall do well to remem-
ber at the same time that even now it is just such hardy
anticipations of experience that make scientific progress
possible, and that nearly every one of the early inquirers
. . . made some permanent addition to the store of posi-
tive knowledge, besides opening up new views of the
world in every direction " (pp. cit. 29).

INTRODUCTION xlv

Seneca probably possessed fuller details of the investi-
gations and speculations of these early workers than we
now do. The existing materials are contained in Pro-
fessor Diels' Die Fragments der Vorsokratiker, with which
his other great work, the Doxographi Graeci, should be
compared.1

The chief work of Aristotle upon which Seneca drew
was the Meteor ologica. The extent to which its subject
coincided with that of the Q.N. may be inferred from a
glance at its contents. The Meteorologica is divided into
four Books, arranged thus : —

I. Scope and relations of Meteorology. The four
elementary bodies — earth, water, fire, air — and their rela-
tions. Celestial fires. Shooting stars. Comets. The
Milky Way. Clouds. Fog. Dew. Hoar-frost. Rain.
Snow. Hail. Wind. Formation of rivers. Change in
land through action of rivers : effects on movements of
races.

II. The sea and its salinity. Theory of the winds,
their varieties, positions, etc. Earthquakes and their
explanation. Lightning and thunder.

III. Lightning, thunder, and similar phenomena. Halo
and rainbow. Mock sun and cognate appearances. Ex-
halation and its influence.

IV. Theory of the elements ( = ingredients or first
principles) ; two active — hot and cold, two passive — dry
and moist. Their effect on bodies. Cohesion, Lique-
faction, Solidification, Coagulation, Fusion, Solubility, and
other properties. Homogeneous and non-homogeneous
bodies. Effects of temperature. Place of this work in
author's scheme.

Another work that goes under Aristotle's name, but is
now generally considered spurious, is the De Mundo (the
Universe}, which in part repeats the subjects of the latter
part of the Meteorology. Seneca may also have drawn
on the De Coelo (the Heavens], whose subject covers
portions of the Q.N. He refers more than a dozen of
times to Aristotle by name, but it was not customary to

1 These are, of course, only for the classical scholar.

xlvi PHYSICAL SCIENCE

refer to individual works. There are numerous instances
in which Aristotle is his authority, though no specific
mention of him occurs.

Theophrastus, the pupil of Aristotle, and his successor
as head of the Academy, is also frequently referred to
in the Q.N. His master bequeathed to him his library
and original manuscripts, and Theophrastus was himself
also a voluminous writer.

Among his extant works on Science, we have treatises
or tracts dealing with Fire ; Winds ; Stones ; Signs of
Rain, Wind, Storm, and Fine Weather ; not to mention
Colours, Odours, etc., and an extensive work on Plants
and their History. His work on Perception and Per-
cepts is said to be a chapter of a larger work on the
history of philosophy. At any rate, it records and dis-
cusses the opinions of earlier writers on the subjects to
which the title refers. For his further views on Physics,
and the lost treatise on the subject, see Diels, Dox. Grate.
119 et sqq., and 473 et sqq.

Aratus, who flourished about 280-270 B.C., wrote two
poems (in Greek) entitled respectively Phaenomena} an
introduction to the knowledge of the constellations ; and
Prognostics, a method of forecasting the weather from
astronomical phenomena. Aratus scarcely ranks as a
scientific writer, but Seneca refers to his opinions on one
occasion in the Q.N. He was apparently held in high
esteem by the Romans, for he found a translator (in
part) in Cicero, and an imitator in Virgil (Georgics).

Plutarch stands in a somewhat different relation to
Seneca. He was a little subsequent in date, but there is
a sort of parallelism between the two, both in their
scientific and their more general interests. Besides the
Physical Causes, already referred to, Plutarch made a
compilation in five Books — at least it goes under his
name — of the Tenets of the Philosophers (Placita Philo-
sophorum} regarding a vast number of physical, especially

1 It is from this poem (1. 5) that Paul quotes (Acts xvii. 28), " For we
are also his offspring." Aratus was a native of Soli in Cilicia, and therefore
a compatriot of Paul.

INTRODUCTION xlvii

astronomical and physiological, subjects. Diels (pp. tit.
65) scouts the idea of the genuineness of the "wretched
epitome," and assigns it to the middle of the second
century. Whether this be so or not does not much affect
its value for us. The existence of the work shows the
nature of the material which was available in Seneca's
age. The work is a kind of distant echo of Theo-
phrastus' lost treatise and preserves many opinions of the
older philosophers, of which, to say the least of it, we
should otherwise have been less fully informed. The
parallelism of the Plaata to the Q.N. will appear from
a few of the titles. Books II. and III. of the former
reproduce a long array of opinions of Thales, Empedocles,
Anaxagoras, Diogenes, Anaximenes, Democritus, Xeno-
phanes, Xenocrates, not to mention Plato, Aristotle, the
Pythagoreans, the Stoics, etc., etc., regarding such sub-
jects as Eclipses, the Milky Way, Comets, Earthquakes,
Clouds, Winds, Thunder and Lightning, etc., etc.

Plutarch also has questions regarding Aratus Prog-
nostics, and a Miscellanea of discussions on allied sub-
jects.

Of Latin writers two have special bearing on Seneca.
Lucretius (95-51 B.C.), in his great poem on Nature (De
Rerum Natura), has expounded the Epicurean view of the
universe. In so far as science is capable of metrical and
poetical exposition, he ranks high among scientific writers ;
while the recent resuscitation of the atomic theory lends
special interest to his views. The Romans were always a
practical and not a speculative nation, and any deviation
from the type, such as Lucretius or Seneca, becomes
especially noteworthy and valuable. Numerous parallelisms
between them have been brought out in the Commentary
and Notes appended to this Translation.

Pliny the Elder stands in respect of date in much the
same relation to Seneca as Plutarch does. His great
work on Natural History, which was addressed to the
reigning Emperor, Vespasian, was published in the year
77, that is, about a dozen years after Seneca's death.
We have already glanced at the bearing of this date upon

xlviii PHYSICAL SCIENCE

that of the publication of the Q.N. We are now con-
cerned rather with the relation of the contents of the two
works. Gibbon (Decline and Fall, chap, xiii.) speaks of
"that immense register where Pliny has deposited the
discoveries, the arts, and the errors of mankind." Nor
is the description unjust. The work is of portentous
length, extending to thirty-seven Books ; it treats of an
enormous variety of subjects, physical, geological, geo-
graphical, ethnographical, botanical, medical, etc., many of
which are now quite dissociated from the title, Natural
History. Pliny seems to have read everything that
existed in writing on the various subjects included, and
his array of authorities attached to the contents of each
Book is very imposing.1 But unfortunately his judgment
does not appear to have been equal to his industry. Every-
thing is recorded, credible and incredible, whether derived
from trustworthy literature or based on mere report : a
more uncritical congeries of truth and error it would be
difficult to imagine.

Book II. deals with the constitution of the universe,
including astronomical and meteorological phenomena,
such as Meteors, Halos, Eclipses, Winds, Earthquakes,
Rain, etc., etc. Many of these cover the same ground
as the Q.N. Among the domestic authors cited for this
Book are M. Varro, Livy, Cornelius Nepos, Caecina,
" who wrote on the Etruscan cult " ; among the foreign
authors are Plato, Anaximander, Democritus, Archimedes,
Aristotle, etc., etc. The omission of Seneca from the
Latin list is balanced by that of Theophrastus from
the Greek list. It is, of course, unsafe to build any
theory on a merely negative basis. Obviously Pliny had
read at any rate portions of these authors, to whom he
elsewhere refers, and may, through mere oversight or negli-
gence, have omitted specific mention of them here : he
usually refers to authors and not to their individual works.
If, at the time of the composition of Book II., which may

1 He claims to have read about 2000 volumes of 100 choice authors, but
his lists seem to include a much larger number of names — 1 46 Roman and
327 foreign writers. See Teuffel, Rom. Lit. vol. ii., under Pliny the Elder.
Cf. Dill, op. fit. p. 146 and note.

INTRODUCTION xlix

have been considerably earlier than the date of publica-
tion of the whole work, he did not know of Seneca's Q.N.,
then the inference seems inevitable that there were current
a collection or collections of the opinions (Sogai) of the
older philosophers which were common property to any
one interested in such matters. The Placita attributed to
Plutarch, though its present form may be much later than
Pliny's time, may have been derived from sources of this
kind. We shall not be far wrong in supposing that, in
addition to the works still extant, there was a mass of
material available to Seneca and Pliny alike which repre-
sented the traditional views on physical and allied subjects
handed down from the old Greek philosophy. Most of
the Latin authors, seventeen in number in all, cited by
Pliny on Book II. are now known to us only by name ;
of those whose works remain, Varro is the only one whom
we should consider likely to furnish much material for the
topic in hand.

Of Pliny's lists in general it may be said that they
indicate that a good many writers even among the
Romans had been attracted by subjects of a scientific or
quasi-scientific character, if we may not venture to say that
their works can rank as science even in the modified sense
in which the term is applicable to Seneca or Pliny. It is
in keeping with the character of the people that practical
sciences like agriculture (Varro, Columella) and architecture
(Vitruvius), not to mention cookery, should have received
special attention. These authors, with others like Manilius
(Astronomicd} and Pomponius Mela (geography), however
interesting in themselves, have only an indirect and some-
times only a remote bearing on the Physical Science of
their day.

VI. THE "QUAESTIONES NATURALES" IN THE
MIDDLE AGES

The Q.N. is a landmark in the progress of Physical
Science. From Aristotle and Theophrastus there is a
great gap until we reach Seneca : the gap is still greater

1 PHYSICAL SCIENCE

between Seneca and the Renascence, from which the era
of true science is to be dated. The Q.N. is the last word
spoken on the subject by the classical world, and practi-
cally the only work of its kind that survives to us in
Latin. Various commentators on Aristotle and Seneca
have, probably unconsciously, appeared as champions of
either author's claim to be considered as the authority
in Science during the Middle Ages. All the materials
for forming an unbiassed judgment are to be found in
Dr. Sandys' History of Classical Scholarship (vol. i.).

Seneca possessed one or two initial advantages. In
the first place, Latin, in which he wrote, was understood
and spoken throughout the world, whereas for many
centuries Greek was over large tracts of it, particularly
in the West, an unknown tongue. Again, Seneca was
for long supposed to be a Christian, claimed by the early
fathers as " one of us," and ranked by Jerome among the
Ecclesiastical Writers. There was not therefore the same
prejudice against his works as is known to have existed
in the early Christian centuries against pagan authors,
especially against the poets.

As a matter of fact, the knowledge of Aristotle's works,
at any rate in the West, seems to have been derived in
the first instance from Arabic translations made in the
ninth century and brought to Spain about the twelfth
century, while from 1204 onwards he was known in
Latin translations made direct from the Greek MSS.,
which were now accessible. "In Roger Bacon's day, not-
withstanding his eagerness for promoting the study of
Aristotle in the original Greek, it was the Latin Aristotle
alone that was studied in the schools " (Sandys, op. cit. 575).
That was about the year 1267. Seneca seems to have
been well known, chiefly as a moralist, through the Middle
Ages. He " was famous as the author of the Naturales
Quaestiones" (ib. 627 *) also. Saint-Hilaire's claim, there-
fore (Arist. Meteor. Pref. ii. iii.), "that Aristotle laid
down the law on Meteorology, as in everything else, from
the age of Alexander right up to the Renascence," must

1 See, besides, pp. 387, 541, 547, 560, 569, etc.

INTRODUCTION

be accepted with some qualification. There seems room
for Ruhkopfs explanation (Q.N. Pref.) that Seneca's work
was, and continued to be, the sole fountain whence Natural
Philosophy derived its source and drew its supplies during
many centuries, " until Aristotle's books were transmitted
for public use into Western Europe."

By the thirteenth century Aristotle had come fully into
vogue, and the references to his teaching in Dante (1265-
1321), said to number upwards of 300, show what a hold
he had obtained upon the greatest man of the age. The
" moral Seneca " is also known to Dante, and placed by
him in the same region of the unseen world (H. iv.), but
the references to his teaching are insignificant by com-
parison (less than ten). Dr. Sandys states (op. cit. 591 ».)
that the references to Aristotle are mainly to the Ethics,
Physics, Metaphysics, and De Anima.

But we are now on the eve of the Renascence, whose
"morning-star . . . arose in the person of Petrarch"
(pp. cit. 650), early in the fourteenth century (1304-1374).
Greek scholarship was reviving in the West, and Petrarch
studied the language in his later days. But his inspiration
was derived in the first instance from Latin, " the philo-
sophical works of Cicero and the moral letters of Seneca "
(op. cit. ii. 4). The latter he cites as many as sixty times
(ib. 7), and he was also familiar with the Senecan tragedies
(ib. 6).

From this and from the general course of history
we seem justified in believing that during the Middle
Ages, in default of any general knowledge of Aristotle,
Seneca was the chief authority on Physical Science.
The views transmitted by him, for they were compara-
tively seldom altogether his own, having obtained currency,
found their way into literature, and probably went far
to colour the conceptions entertained on the subject
in all the earlier literature of Modern Europe. Later,
when Aristotle's works became more widely known, his
authority became supreme alike in philosophy and in
science. Nor does the temporary ascendancy of Seneca,
though historically very important, carry with it any pre-

PHYSICAL SCIENCE

sumption of rivalry, not to say superiority, to Aristotle.
Seneca may best be regarded as pupil and interpreter of
Aristotle, in so far as the two come into competition.
His date, the language employed as his medium, his
position, his reputation as a Christian, and his activity in
other fields, all conspired to give him a position in the
Middle Ages which is not necessarily the measure of his
intrinsic merit as compared with Aristotle.

VII. THE PRESENT TRANSLATION

From what has preceded, it will appear that the path
of the translator of the Quaestiones Naturales is beset with
snares. At best he has a choice of difficulties. It may
perhaps, therefore, be well to say a word or two upon the
method in which these have been dealt with on the present
occasion.

A translator's prime duty is to follow his author, for
which purpose he must first understand him, a requirement
not very easily here fulfilled. The texts of the Q.N. vary
greatly, as already indicated, and it is no easy matter to
select any one that might be consistently followed. The
most recent and best text, the Teubner, edited by Gercke,
has strong claims, and had it been my good fortune to have
it by me when the translation was made, I should have
been tempted to adopt it simpliciter, even though in many
details it departs somewhat violently from the accepted
arrangement. As it was, it did not come to hand until
the translation was finished and paged for publication, so
that full use could not be made of it. In a few cases its
corrections had been anticipated ; in some its readings
have been adopted ; some that could not be incorporated
are referred to in a note on the subject.

The text being settled, the translator must, if possible,
put himself in the author's position and obtain his point
of view.

In science, particularly, the milieu of the author
must be caught if his thoughts are to be accurately

INTRODUCTION liii

reproduced. The danger of attributing to Seneca ideas
that were unknown to him and that are due to modern
analysis and discovery has to be constantly present to
one's mind. For example, " homogeneity," " elasticity,"
" electricity," " gas," " explosion," etc., are a few of the
terms that his language suggests, but that would probably
convey a wrong impression of his conception of the
phenomena to which they relate. They have been thus
ruled out. Nor is Seneca consistent in the use of the
terms he employs ; he has no scientific vocabulary. In a
separate note attention is called to his words for " air "
and " atmosphere " ; but there are many other terms that
belong to the same category. These are, for instance,
three words for " thick " or " dense," crassus, densus, spissus,
which he seems to use almost indifferently, at any rate
without any precise discrimination. So with terms like
" impetus " (impulse, onset) " impulsus " (shove, impulse),
" ictus " (stroke, blow), " vis " (force, quantity, amount),
" curro " (to run (river), to revolve (heavenly body)), and
its compounds, eo (to go), and its compounds, etc., etc.

Apart from any peculiarity of Seneca, Latin allows
the use of adjectives and pronouns, whose distinctive
gender points their reference, where English requires
substantives or their equivalent. Latin, too, often conveys
by mere suggestion where English requires explicit ex-
pression. This is particularly so with connectives, where
a separate clause may be required to develop the nuance
of a subtle collocation. In general, assuming — and it is
no great stretch — that the author meant to express some-
thing, whether right or .wrong, I have endeavoured to
ascertain what that something was and to convey it to
the English reader. In doing so I have had no scruple
in using more words than Latin, or in making explicit
what I conceived to be implicit, or in varying the render-
ing of the same term to suit the context and idiom.
Ambiguity has, as far as possible, been avoided and even
removed. At the same time the author has been followed
as closely and faithfully as may be. Where he repeats
a term purposely, as he frequently does, the repetition is

liv PHYSICAL SCIENCE

retained, though a variant might have sounded more
euphonious. Probably, in some cases — it may be in a
good many — the meaning has been misconceived; certainly,
there will be difference of opinion in regard to readings
adopted for translation, where one had to be taken and
two or more almost equally good had to be left out.
Ruhkopf was the text chiefly used ; in addition Koeler
and the Variorum Edition of Bouillet were constantly at
hand, and I have been much indebted to all three in
questions of interpretation. Nisard's French Translation
has also been of some service, indirectly by suggestion
perhaps rather than directly ; in a few passages the
translation is from a different text from that printed on
the same page. The old Tauchnitz text has been habitu-
ally consulted, while Gercke's text has been carefully
collated throughout. The latter does not mention Ruhkopf
at all in his Bibliography — surely an involuntary omission.
There is a useful Bibliography also in Bouillet, but the
date of his Edition is as far back as 1830. To my
regret I have not been able to procure Lagrange's famous
French Translation, and the same remark applies to several
German works of repute. Lodge's Translation (1614) was
not of any service for my purpose.

THE NATURAL QUESTIONS OF L. ANNAEUS
SENECA ADDRESSED TO LUCILIUS

BOOK I
[METEORS, HALO, RAINBOW, MOCK SUN, ETC.]

PREFACE

LUCILIUS, my much esteemed friend — While a great i
gulf separates philosophy from the other learned
arts, there is to my mind an equally wide gulf in
philosophy itself between the portion which relates
to human conduct and that which deals with the
nature and power of heaven. The latter is more
exalted and more speculative, it allows itself wide
liberty. It is not satisfied with mere observation,
it surmises that there is a greater and fairer realm
placed by nature beyond human sight. Between
these two divisions of philosophy, in short, there is
as wide a gulf as between their subjects, God and
man.

The one teaches us what should be done 2
on earth ; l the other, what is done in heaven.
The one dispels our errors and flashes a light by
which to thread the mazes of life ; the other far
transcends this gloom. in which we grope, rescues
us from the darkness, and leads us to the very
source of light itself. For myself, I am grate-
ful to nature, not so much when I see her on the
side that is open to the world, as when I am per-
mitted to enter her shrine. Then one may seek to
know of what stuff the universe is made, who is its
author or guardian, what is the nature of God. Is

1 In other words, the principles of human conduct.
3

PHYSICAL SCIENCE

He wholly absorbed in Himself, or does He some-
times regard us ? does He do something daily, or
has He done once for all ? is He a portion of the
world, or the whole world? may He issue new
decrees even to-day and thus modify the laws of
fate, or is it an infringement of His majesty and an
acknowledgment of error to alter what has once been

3 made ? for surely the same must always please
Him who can be pleased only with what is best.
Nor yet withal is His freedom or power diminished,
for He is a law unto Himself.

Life would have been a useless gift, were I not
admitted to the study of such themes. What
cause for joy would it be to be set merely in
the number of those who live ? In order to digest
food and drink ? To repair a diseased, enfeebled
body, that would perish unless it were continually
refilled, and thus lead the life of a sick man's
attendant? To fear death, to which our very
birth destines us ? Away with the priceless boon !

4 Life is not worth the heat and the sweat. How
despicable a creature is man, unless he rise above
the earth ! What great thing can we do as long as
we have to wrestle with our passions ? Even if we
prevail, we but conquer monsters. What cause
have we to esteem ourselves because we are not
quite so bad as the very worst ? I can see no great
reason for self-satisfaction because one's strength is
rather above the average of those in the same
hospital. You are still far from good health and
vigour. Or, again, you have escaped vices of soul,
the hypocrite's brow, the flatterer's speech fashioned
to serve another's will, the dissembler's heart, the
miser's spirit, which robs all, but yet mortifies itself.
You are a prey neither to luxury, which loses basely

PREF. DIVINE PHILOSOPHY 5

and repairs its losses still more basely ; nor to
ambition, which leads to place of worth only by 5
unworthy means. But yet you have accomplished
nothing. You have escaped many perils, but not
yet [that of] self! The virtue we aim at raises to
a splendid eminence ; not so much because escape
from vice is in itself a blessed thing, but rather
because the soul is emancipated, prepared for the
knowledge of heavenly things, and rendered worthy
of entering into communion with God.

The full consummation of human felicity is
attained when, all vice trampled under foot, the soul
seeks the heights and reaches the inner recesses of
nature. What joy then to roam through the very
stars, to look down with derision on the gilded
saloons of the rich and the whole earth with its store
of gold ! Gold, did I say ? Yes, all the gold the
earth ever produced and sent into currency, and all
that she keeps hidden in secret to glut the avarice of
posterity. Only when one has surveyed the whole 6
universe can one truly despise grand colonnades,
ceilings glittering with ivory, trim groves and cooling
streams transported into wealthy mansions From
above, one can now look down upon this narrow
world, covered for the most part by sea, and, even
where it rises above the sea, an ugly waste either
parched or frozen. The philosopher says to himself :
Is this the plot that so many tribes portion out by
fire and sword ? How ludicrous are their frontiers !
The Dacian must not pass the lower Danube ; 7
the Strymon must shut off the Thracians ; the
Euphrates must be the barrier of the Parthians ;
the Danube must form the boundary between Sar-
matian and Roman ; the Rhine must set a limit
to Germany ; the Pyrenees must raise their chain

PHYSICAL SCIENCE

between Gallic and Spanish provinces ; between
Egypt and Ethiopia a desert of barren sands must
stretch ! Why, if ants are ever endowed with human
intelligence, will not they in like manner portion
out a threshing-floor into many provinces ?

8 But when you rise to what is truly great, then, as
often as you see armies marching forth with floating
banners, and the cavalry now scouting in front, now
massed on the flanks, as if some great design were
toward, you will pleasantly remark :

The black swarm is hurrying through the plains.

That host is a throng of ants, its evolutions are
in a back garden. In what do we excel the ants,
save in the measure of the puny little body ? That
is a mere point in which you sail, and war, and dis-
pose your kingdoms. Your kingdoms are lilliputian
even when they stretch from Ocean to Ocean.

9 Only on high are the domains spacious ; to their
possession the mind is admitted, provided always
that it bring with it no taint of the body, but wipe
off all stain and pass forth like an armed man,
lightly equipped, nimble, modest in his wants.
When the soul reaches those regions, it receives
nourishment and growth ; as if freed from the
shackles of earth, it returns to the true source of its

10 being. A proof of its divine origin is furnished
by the pleasure it derives from what is divine ; here
it feels itself at home, not in a strange land.
Without alarm it views the setting of the stars and
their rising, and the mazy orbits of the heavenly
bodies that yet move all in unison. It notes when
each star first shows its light on earth, when it
attains its meridian height, observes its orbit and
the limits of its descent. An interested spectator, it

PREF. NATURE OF DEITY 7

examines and investigates every detail. And why
should it not? It feels that they are akin to itself.
Then contempt for the narrow limits of its former u
dwelling succeeds. For what after all is the space
that lies from India to the farthest shores of Spain ?
A few days' journey if a prosperous wind waft the
vessel. But that heavenly region affords a route
during full thirty years to the swiftest of the planets,
rushing with untiring velocity, never once halting.

Here at last the soul comes to learn what it has
long sought, it begins to know God. But what is 12
God ? The universal intelligence. What is God,
did I say ? All that you see and all that you
cannot see. His greatness exceeds the bounds of
thought. Render Him His true greatness and He
is all in all, He is at once within and without His
works. What, then, is the difference between the
divine nature and the human ? In us the better 13
part is spirit, in Him there is nothing except spirit.
He is wholly reason : though mortal eyes are so
sealed by error that men believe this frame of things
to be but a fortuitous concourse of atoms, the sport of
chance. And yet than this universe could aught be
fairer, more carefully adjusted, more consistent in
plan ? But men will have it that it is tossed about
at random in the confusion of thunder, cloud, and
storm, and the other forces by which the earth and
its purlieus are haunted.

Nor is this merely the madness of vulgar error;
even the philosophers are tainted by it. Men 14
there are who think that they themselves have a
mind, one, too, that foresees and orders events
in detail whether relating to themselves or to
others. But this frame of things, in which we
men along with the rest of creation are set, they

8 PHYSICAL SCIENCE BK. i

deem void of counsel, hurried hither and thither at
random ; or at best, nature, they suppose, does not
know what her own aim is. How profitable then,
think you, will it be to ascertain the truth on such
questions and exactly to define each position ! For
example, what is the extent of the power of God ?
Does He create matter or does He employ
matter already given ? Does the pre-existing
archetype give shape to matter, or does the matter
determine the shape ? Can God perform anything
He wishes, or does material fail Him in many
15 cases, just as a great artist often produces inferior
work, not through any defect in his art, but because
the material on which it is exercised is refractory ?
To search into such things, to learn them, to medi-
tate upon them — why, is it not in effect to transcend
the limits of mortality and to be enrolled a citizen
of a higher state? What good will it do you,
you ask. Well, if nothing else, I shall, at any rate,
know that measured by divine standard all earthly
things are mean. But of this more anon.

To come now to my purpose — listen to the explana-
tion offered by Natural Philosophy concerning the
Fires which the atmosphere drives athwart. Their
oblique course and amazing velocity furnish proof
that they are thrust out with great violence. Evi-
dently they do not come forth of themselves, they
are shot out. There are many different forms of
them. A certain kind of them Aristotle calls a She-
Goat. If you ask me why, I must retort by asking
you first to explain why they are also called Kids.

i METEORS 9

It will, perhaps, be more to the purpose not to 2
cross-examine one another with questions such as :
What does such and such an author say ? Answer
me. Better examine the cause of the phenomenon
itself than form surmises as to why Aristotle has
applied the name She-Goat to a ball of fire. This
was the shape of the one as big as the moon that
appeared when Paulus was engaged in the war
against Perseus. In our own days we have more
than once seen a huge ball-shaped flame which
broke up in the very middle of its course. We 3
saw a similar portent about the time of the death
of the late Emperor Augustus. We again saw one
when Sejanus was executed. A warning of the
same kind preceded the death of Germanicus.

You may, perhaps, exclaim : Are you then so
benighted as to suppose that the gods send out
previous intimation of the death of great men ? Do
you imagine that anything on earth is so great
that the Universe should perceive its loss? That
question must be reserved for another season. We
shall then see whether a fixed succession is observed
in all events, and whether one event is so bound up
with another that what precedes is either cause or
at least token of what follows. We shall then 4
see, too, whether the gods trouble themselves about
human concerns, and • whether the mere series of
events reveals by unmistakable signs what its effects
must be. Meantime, I venture the opinion that
fires of the class referred to are produced by violent
friction of the atmosphere. The pressure inclines
toward one or other side, and as there is no yielding
there, an internal struggle ensues. From violent
action of this kind arise the different varieties of
fires — beams, balls, torches, and gleams. When the

PHYSICAL SCIENCE

shock is less severe, and the atmosphere is merely
grazed, as it were, smaller lights are emitted,

And the flying stars drag their hairy tail.

5 Then their thin fires mark a slender path, which they
prolong across the sky. For that reason no night is
without sights of the kind ; no great movement of
the atmosphere is required to produce them. In
fact, to put it shortly, they are due to the very same
cause as thunderbolts, only they require less force.

Clouds that encounter each other with little force
cause flashes of lightning; if impelled by greater

6 violence, thunderbolts. Aristotle offers the following
explanation : The earth gives forth many different
exhalations, some moist, some dry, some cold, some
containing the seeds of fire. And little wonder if the
earth's evaporation is of all varied kinds. Why,
even in the heavens the colour of objects does not
show uniform ; the red of the Dog-star is brighter,

7 that of Mars duller ; Jupiter has no red, his sheen
is prolonged into pure light. Well, in the great
abundance of minute bodies emitted by the earth
and driven up to the higher regions, of necessity
some of the elements that reach the clouds furnish
material for fires. They do not require any collision
in order to burn, the breath of the sun's rays is
sufficient to kindle them. So with us, shavings

8 sprinkled with sulphur catch fire at some distance.
Probably, therefore, tinder of this kind gathering
within the clouds is easily kindled ; greater or less
fires are produced just as there has been more or
less substance in the elements.

On the other hand, to suppose either that
actual stars fall or leap across the sky, or that
some portion of them is taken away or pared off,

THEIR PROGNOSTICATIONS

is sheer folly. If this had been so, they would 9
ere this have disappeared. For there is not a
single night on which there is not a very large
number of stars that seem to break up as they
pass across the sky. Yet they are all found again
in their wonted places : each one maintains its size
unimpaired. It follows, therefore, that the fires
referred to have their origin below the stars, and
that, being without solid foundation on fixed abode,
they quickly perish. Why, then, you ask, do they
not cross the sky by day as well as by night? 10
The next thing you will say will be that there are
no stars by day because they are not visible !
The stars are, of course, there, but obscured by
the sun's brightness. Similarly, meteor fires like
torches cross the sky by day too, but they are
hidden by the brightness of the daylight. If,
as sometimes happens, a burst of light shoots out
strong enough to assert its brilliance even in the
face of day, then they do become visible. In fact, n
our own age has more than once seen torches by
day, some rushing from east to west, others from
west to east.

Sailors consider it a sign of storm when there
are many shooting stars. If their appearance
really is a sign of wind, they must occur in the
quarter where wind • is found, in other words,
in the atmosphere which lies between the earth
and the moon. In violent storms at sea there
sometimes appear, as it were, stars settling on
the sails. The sailors who are in jeopardy then
suppose that they are being aided by the power of 12
Castor and Pollux. They have really ground for
better hope in this appearance, because it makes
plain that the storm is breaking, and the wind

PHYSICAL SCIENCE

falling. Otherwise the fires would flit about without
settling. When Gylippus was on the voyage to
Syracuse, a star appeared, resting on the very tip
of his lance. In the camp of the Romans at times
pikes appeared to be on fire, no doubt because fires
of this kind glided down on to them : these fires are

13 often wont to strike animals and trees, just like
thunderbolts. If, however, they are discharged
with less force, they merely glide down and settle,
and do not inflict stroke or wound. Again, some
are forced out from among clouds, others come from
a clear sky, if the atmosphere has got into a condi-
tion to emit fire. In like manner, it occasionally
thunders with a clear sky, and from the same cause
as with a cloudy one, the atmosphere undergoing
internal collision. Even when the air is compara-
tively clear and dry, it may become condensed, and
form bodies similar to clouds, the clashing of which

14 causes the sound of the thunder. From time to
time, therefore, arise meteors like beams and like
shields, and the semblance of vast fires over the
sky, if a force similar in kind but greater in degree
encounter suitable material.

II

LET us now see how the brightness is produced
that sometimes envelops the heavenly bodies.
History has put on record that, on the day of the
late Emperor Augustus' entrance into Rome on
his return from Apollonia, a parti -coloured circle,
such as is wont to be seen in a rainbow, appeared
round the sun. The Greeks call this a Halo ;
our most appropriate name for it is a Crown.

ii HALO 13

Let me explain how it is formed. When a stone 2
is thrown into a pond, the water is observed to
part in numerous circles, which, very narrow at
first, gradually widen out more and more until
the impulse disappears, lost in the surface of the
smooth water beyond. Let us suppose something
of the same kind to occur in the atmosphere.
When condensed it is capable of receiving an im-
pact : the light of sun, moon, or any heavenly body
encountering it forces it to recede in the form of
circles. Moisture, be it observed, and air, and
everything else that takes shape from a blow, is
driven into the same form as that possessed by the
object that strikes it. Now every kind of light is 3
round. Therefore, the air when struck by light will
assume this form. Accordingly the Greeks gave
the name Threshing-floor (i.e. Halo) to a brightness
of this kind, because spaces set apart for threshing
corn were, as a rule, round.

Be the better name threshing-floors, or be it
crowns, there is no reason to suppose that they
are formed in the neighbourhood of the heavenly
bodies. They are a very long distance from
them, though as seen from the earth they seem
to touch and encircle them. In reality such an 4
image is formed not very far from the earth, but
the wonted frailty of .human vision is deceptive,
and we imagine the ring is formed close round the
heavenly body itself. But no such thing could
possibly occur in the neighbourhood of the sun and
stars, as there is nothing but thin ether there. It
is only when bodies have become rough and dense
that shape can be impressed upon them. In subtle
bodies there is no point on which form can lay hold
or to which it can adhere. A phenomenon of the

14 PHYSICAL SCIENCE BK. i

same nature as the halo may often be witnessed
in baths, because the atmosphere is thick and dark :
it is most frequent when the wind is in the south,
when the air is heaviest and most dense.

5 Halos sometimes are dissolved gradually and
fade away, sometimes they are broken up on
one side. In the latter case seafaring men look
for wind in the direction in which the circle of
the crown has been broken. If the parting is on
the north, there will be a north wind, if on the
west, zephyrs will follow. This is a proof that
these crowns are formed in the region of the sky
in which the winds are usually formed. The
upper regions of air have no crowns because they

€ have no winds either. An additional proof of the
connection of winds and halos is afforded by the
fact that the halo is never formed unless the atmo-
sphere is at rest, and the wind, as it were, inactive.
Under other circumstances it is not usually observed.
The atmosphere when it is at rest may be
fashioned to any pattern by being driven or drawn in
any direction. But when it is in motion, light cannot
even strike it. It takes no shape and offers no
resistance, because the part first affected is always

7 dissipated by the motion. Therefore it is that no
heavenly body can ever be surrounded by a figure of
the kind referred to unless when the atmosphere is
dense and motionless, and so preserves the ray of
round light that strikes upon it. Nor is it without
good reason. Recollect the analogy mentioned a
little ago. A pebble thrown into a pond or lake or
any other circumscribed piece of water produces
innumerable circles ; but it has not the same effect
if thrown into a river. And why so ? Because in
the latter case the water as it hurries on prevents

ITS CAUSE 15

the formation of any definite figure. So in the atmo- 8
sphere the same thing happens ; when it is stationary,
it may receive a pattern ; when it rushes in rapid
motion, it evades all control, warding off every
blow and every form as it approaches. When these
crowns, of which I have spoken, have disappeared
uniformly on all sides, and vanished in their own
tracks, it is an indication of equilibrium in the atmo-
sphere : there is perfect quietness and you may then 9
look out for rain. When they break up at one side,
it means wind in that quarter. If they burst at
several points, a storm is brewing. The reason of
this may be gathered from the explanations I have
now given. If the ring fade all round, it is evident
that the atmosphere is equable, and therefore calm.
But if it is broken through on one side, evidently there
must be an inclination of the air in that direction :
hence that quarter will produce wind. But when the
halo is rent and torn on all sides, plainly an attack is
being made on it from several quarters at once, and
a disquieted atmosphere is assailing it on this side
and on that. So this disturbance of the heavens, 10
the repeated effort and striving in all directions,
betokens evidently that a storm is coming up with
sudden shiftings of the wind.

These crowns may be observed generally by
night round the moon and other stars, but very
seldom by day ; in fact, so rarely in the latter case,
that certain of the Greeks have denied that they
appear at all by day. But history proves that
they do. The cause of the infrequency of their
appearance by day is that the sun's light is stronger
then, and the atmosphere itself when stirred and
warmed by it is less dense. The moon's power, on
the other hand, is feebler, and is therefore more

16 PHYSICAL SCIENCE BK. i

easily resisted by the surrounding air. The rest of
the heavenly bodies are equally weak, and unable
by their own force to burst through the atmosphere.
So their shape is impressed and retained in the
more solid and less yielding medium. For, in order
to produce the phenomenon, the atmosphere must
neither be so thick as to exclude or dissipate the
light that streams in on it, nor yet so thin and rare as
to furnish no hold to the rays that fall upon it. This
particular consistency is obtained at night : the
sluggish air is at that time struck with the faint light
from moon or stars without violence or rudeness,
and, being thicker than it is wont to be by day, is
tinged thereby.

Ill

1 ON the contrary, the Rainbow does not occur by
night, except on very rare occasions, inasmuch as
the moon has not sufficient strength to pierce the
clouds and suffuse them with hues such as
they receive from the brilliant light of the sun.
The shape and varied colours of the rainbow are
due to the peculiarities of different kinds of clouds.
Some parts of the clouds are swollen, others
hollow ; some are too dense to transmit sunlight,

2 others too rare to exclude it. This difference in
consistency causes alternations of light and shade,
and produces that marvellous variety presented by
the rainbow. Another explanation is offered in
instances like the following : When a pipe bursts
anywhere, the water is observed to be forced by
pressure through the small opening ; the drops
seen against a slanting sun reproduce the appear-
ance of the rainbow. Again, if you will at any

RAINBOW 17

time watch a fuller at work, you will observe the
same appearance : when he has filled his mouth
with water and spirts it lightly on the clothes
stretched on pegs, the air thus besprinkled ex-
hibits plainly the various colours that shine in
the bow. One cannot doubt that the reason of 3
this lies in the moisture. For a rainbow never
occurs except when there are clouds about.

Let us inquire how it is produced. Some
authorities say that there are certain drops • of
water that transmit light, while some are too com-
pact to be translucent. Thus the brightness is the
effect of the former; the shadow, of the latter;
by the intermingling of the two is formed the
rainbow, part of which is bright, to wit, that which
admits sunlight, part darker, namely, that which
has shut out the light and cast a shadow from itself
over the objects nearest it. Others again deny that 4
this is so. Shade and light, they say, might be the
cause if the rainbow had only two colours, and
thus was made up of light and shade.

But now, though there gleam a thousand diverse hues,
Their changes withal elude the eyes that behold.
The hues that touch seem actually one, yet the edges are quite
different.

In it sight detects something that is red, something
that is orange, something that is blue ; and there
are other colours too, laid on in finest lines just
like a skilful painting, so that, as the poet remarks
above, it is impossible to discover whether the
colours differ from one another until the last of
them is compared with the first. The junction of 5
colour with colour deceives the sight : with such
marvellous skill does nature starting from what is
like end in what is totally unlike. What good, then,

1 8 PHYSICAL SCIENCE BK. i

do the two alleged colours, light and shade, do in
a case of this kind, when the presence of an endless
variety must be accounted for ? Again,

certain authorities are of opinion that the following
is the method of formation of the rainbow : In the
quarter of the sky where rain is falling, they say,
the drops of falling rain are so many mirrors ;
from each mirror, therefore, is reflected an image
of the sun. By and by, many, in fact, countless,
images, descending and crossing abruptly, are all
blended together. Therefore the rainbow is just a
blending of a great number of images of the sun.

6 They appeal to the following argument in proof of
this : On a clear day, say they, set out a thousand
basins, and they will all contain images of the
sun. Or arrange single drops of water on single
leaves ; they will each have an image of the sun.
On the other hand, an immense pond will have no
more than one image. Why so ? Just because
every smooth surface that is fenced off, and sur-
rounded by its own boundaries, is a mirror. Again,
divide a pond of very large size into several small
ponds by inserting partition walls ; it will show as
many images of the sun as it has divisions. Leave
it as it was, spreading out to its full extent, and it

7 will show but one reflection of him. The small
extent of the liquid or pond makes no manner of
difference. If the surface is circumscribed, it forms
a mirror. Well then, those countless drops, which
are carried down by a falling shower, are so many
mirrors, and contain so many reflections of the sun.
To an observer right in front of them they
present the appearance of being mixed up : the
intervals which part them from each other are not
distinguished, their mere distance from the observer

in ARISTOTLE >S EXPLANATION 19

prevents discrimination of them. By and by
instead of individual drops there is seen a single
blurred mass that contains them all.

Aristotle agrees with this opinion. His words
are : Beams of light are reflected by sight y\
from every smooth surface. Now, nothing is 8
smoother than water and air. Therefore, our
sight is reflected back on us from thick air.
Indeed, where the vision is dull and feeble,
the slightest stroke of air checks it. Some
people suffer from an affection which causes
them to think that they are meeting their own
image, and they see everywhere the reflection of
themselves. And why ? Because the power of
their eyes is so weak that it cannot overcome the
resistance of even the nearest layer of the
atmosphere. What dense air effects in ordinary
cases, any kind of air is sufficient to effect in
the cases referred to by Aristotle. For whatever
the nature of the air, it is strong enough to defeat
weak sight. Now, much more is our vision

reflected upon us by water because it is denser
and cannot be pierced ; it absolutely stops the
rays from our eyes, and turns them back to the
source whence they proceeded. Well then, 9

when there are numerous raindrops, they are
just so many mirrors. ' But on account of their
smallness they express the sun's colour without
distinct shape. By and by when the same colour
is reflected in the countless drops that fall without
intermission, it begins to take on the appearance
not of numerous images with intervals between, but
of a single, long, uninterrupted image.

But how, you may object, can you tell me that there
are many thousands of images there, where I can

20 PHYSICAL SCIENCE BK. i

10 see none at all- ? Besides, as there is but one colour
in the sun, why are there different colours in the
reflections of him ? These objections which you
have put forward, as well as others that no less call
for refutation, I will endeavour to refute. And let
me say, first of all, that nothing is more deceptive
than our eyesight, not merely in objects whose
careful examination is prevented by distance in
position,1 but even in objects seen close at hand.
An oar, though quite whole, presents the appear-
ance of being broken when seen in clear shallow
water. Apples seen through glass appear much

11 larger than they really are. In long colonnades,
pillars set at intervals present an apparently un-
broken continuity of line. Or go back to the case
of the sun himself; his orb, which reason proves
to be larger than the whole earth, is so contracted
by human sight that some of the philosophers have
maintained that it is only a foot in diameter. He
is, we know, the swiftest of all luminaries, yet none
of us can see him move ; nor should we believe
that he does advance, were it not evident from time
to time that he has advanced. The world itself
glides on with headlong speed ; within an instant of
time it unfolds its risings and its settings, yet none

12 of us is aware of its movement. What cause, then,
is there for wonder if our eyesight cannot separate
the drops of the rain showers, and loses the dis-
tinction of the images on account of the vast
distance at which they are beheld ? At any rate
no one can doubt this, that the rainbow is a
reflection of the sun, formed in a hollow cloud full
of moisture. This is made plain from the simple fact
that the image is never seen except opposite the sun,

1 The received text gives "diversity of colours."

COLOUR OF RAINBOW

high up or low down, in inverse relation, just as he
sinks or elevates his course. When he descends,
it is higher ; when he is high in the heavens, it is
more sunken. A cloud of the required kind is 13
often at the side of the sun without producing a
rainbow, because it does not catch his image
straight in front.

As to the variegation in colour, it is due
simply to its double source, derived partly from
the sun, partly from the moist cloud. The mois-
ture produces lines now blue, now green, now
purple-like, and orange or red — the two shades,
dull and bright, combining to produce this diversity.
So also, a purple garment does not always come 14
out in exactly the same tint from the same dye.
Differences depend upon the length of time it has
been steeped, the consistency and the amount of
moisture in the dye it has imbibed : it may be
dipped and boiled more than once, or it may have re-
ceived only one immersion. In like manner then,
when there are the two elements, sun and cloud,
in other words, object and mirror, it is little wonder
that as many varieties of colour are generated as can
be produced from them in higher or lower tone in
countless different categories. For example, there 15
is one colour that proceeds from the light of fire,
another from a light that is duller and less violent
than fire. In other details concerning the rainbow
the method of inquiry is full of uncertainty ; there
is nothing concrete to lay hold upon, and conjecture
must be ventured in every direction. But in this
question of its origin doubt is precluded ; for it is
evident that the causes of the rainbow are two in
number, sun and cloud. The bow never appears
when the sky is clear, and never when it is so

22 PHYSICAL SCIENCE BK. i

cloudy as to hide the sun. It must, therefore,
unquestionably arise from these, failing either of
which it cannot come into being.

IV

A FURTHER consideration must be mentioned, which
is just as manifest as the preceding, to prove
that the reflection is given back after the fashion
of a mirror ; it is never given back save from
straight opposite to the sun, that is,1 unless on
one side stands the object to be reflected, and on the
other the mirror that reveals it. Proofs are adduced
by the mathematicians that are not merely convinc-
ing but that compel belief of this. Nor can doubt
be left in any mind that the rainbow is an image of
the sun, imperfectly reflected owing to the defective
shape of the mirror. But meantime let us

recall other proofs that may, so to speak, be picked
up in the street without any reference to mathe-
matics. Among the proofs of this origin of the bow
I place the extreme rapidity of its emergence. In
a single moment the huge form with its thousand
lines is inwoven in the texture of the heavens, and
just as rapidly does it fade. Now, nothing is
returned so quickly as an image from a mirror.
The mirror does not create anything, it merely
reveals it. Artemidorus of Parium tells us further
even the kind of cloud required to reflect such an
image of the sun. If you make a concave mirror,
he says, that is, one resembling half of a ball cut
through the middle, and take your stand outside
the centre, then those who stand beside you will

1 In a writer less prone to repetition the words to the end of the sentence
would seem the insertion of a copyist.

iv MIRROR AND IMAGE 23

appear in the reflection inverted and nearer to you
than to the mirror. The very same thing, accord- 4
ing to him, takes place when we look at a round
hollow cloud from the side : the image of the
sun detaches itself from the cloud, and is nearer
us and more turned in our direction. Therefore
the red colour is from the sun, the dark blue is
from the cloud : the other hues are produced by a
blending of these two.

BUT there are arguments on the other side. About i
mirrors there are two opinions ; some people think
that only phantoms are seen in them ; in other
words, the shape of our bodies, an emanation sepa-
rated from our bodies. Others, however, affirm
that images do not exist in the mirror, but that it is
the very bodies that are seen, the eyesight being
bent back and reflected on itself again. Now, the
point is not how do we see whatever it is we see :
the question is, how the image should resemble the 2
original in the cloud as in a mirror.1 Could any-
thing be more unlike than the sun and a rainbow in
which neither the colour nor the shape nor the size
of the sun is to be seen ? A bow is far larger
and, in the bright part, far redder than the sun : in
the other colours, too,- it is different from him.
Besides, when you insist on comparing a mirror to
the atmosphere (i.e. as embodied in a cloud), you
must show me in the latter the same smoothness of
texture, the same levelness of surface, the same

1 The reading of the MSS. is admittedly corrupt. I have followed Ruhkopf 's
conjecture, though without conviction. The argument seems to require dissimi-
lis = unlike, or non similis (cf. c. v. 13), instead of similis = like ("re-
semble " in the text) : in that case the meaning would be : how an image
unlike the original ought to be reflected from the cloud as from a mirror.
Cf. § 13 below.

24 PHYSICAL SCIENCE UK. i

brightness as in the former. But surely no clouds
resemble mirrors to this extent. We often pass
through the middle of clouds without seeing our-
selves in them. People who climb to the tops of

3 mountains look down on cloud, but cannot make
out their reflection in it. True enough,
but it is separate drops that are separate mirrors,
says my opponent. Admitted. Still, I deny
that a cloud consists of fully formed drops. It
no doubt contains the elements from which the
drops are formed, but not as drops. Clouds do
not contain even water, but only the material to
form water. Granting, for the sake of argument,
that there are countless drops in the clouds and
that they can reflect an object, yet they do not
all produce one and the same reflection, but each

4 its own. Further, you may join mirrors to one
another, but they will not unite to form a single
reflection : each portion will enclose a likeness of the
object. Some mirrors are composed of a large number
of very small parts. Set before them one man and a
whole people is reflected, each portion producing an
image of its own. The portions of the mirror thus
united and placed side by side none the less keep
their images separate, and out of one man make

5 a crowd. But they do not blend in one that
troop ; they separate and distinguish the individual
faces. Now, a rainbow is bounded by a single
outline, the whole presents but one representation.

Well, but, says our opponent, is not the water
that is scattered from a burst pipe, or that is
tossed up by the oar, wont to exhibit something
similar to these colours that are seen in the bow ?
True, but not for the reason which you wish to
bring out, to wit, that each single droplet receives

v COLOUR EFFECTS 25

an image of the sun. As a matter of fact, the 6
drops fall too quickly to be able to form such an
image. The medium must be stationary in order to
receive the impression of what is to be reproduced

How, then, it may be asked, does it come about ?
The drops, I reply, receive the colour, but not the
image of the sun. Besides, as Nero Caesar says
very elegantly :

The neck of Venus' dove glitters as the bird tosses its head,

and so the neck of the peacock shines with varied
colours as often as it is turned hither and thither.
Are we, therefore, to say that feathers of this kind, 7
whose every turn passes into new colours, are
mirrors? Well, clouds differ in character from
mirrors no less than the birds mentioned, and as
chameleons and the other animals whose colour
changes. In the latter case the cause is sometimes
subjective : the creatures when inflamed with anger
or passion vary their hue through the suffusion of
moisture : at other times the position of the light,
direct or slanting, gives the colour its particular hue.
What resemblance, I say, is there between mirrors 8
and clouds? Whereas those are not translucent,
these transmit light. Those are dense and com-
pact, these are rare. Mirrors are of uniform material
throughout, clouds are made up of various ele-
ments brought together at random, and therefore
are full of internal strife, and cannot long hold
together. Consider further ; at sunrise one sees a
certain portion of the sky ruddy ; at other times
one sees clouds of fiery red. This particular colour
is received by the clouds from encountering the sun :
what, then, is there to prevent the many colours of
the bow being derived by them in the same way

26 PHYSICAL SCIENCE BK. i

from him, even though they do not possess the
9 power of mirrors ? A little ago, my oppo-

nent retorts, you advanced the argument that the
rainbow is always produced opposite the sun, be-
cause an image could not be reflected from a mirror
unless the object were in front of it. We agree
in this point, he adds. Yes, for just as the object
whose image is to be transferred to the mirror
must be set opposite the mirror, in like manner,
in order that the clouds may be tinged by the
sun's rays, the sun must occupy a suitable posi-
tion. He does not produce the same effect if
his light streams in on all sides ; there must
be a proper incidence of the rays to produce
the effect. Such are the reasons alleged by

those who will have it that the rainbow is a coloured
cloud.

Posidonius and those who are of opinion that
the phenomenon is produced by reflection as from

10 a mirror, answer their arguments thus : If there
were any real colour in a bow, it would persist,
and be seen more distinctly, the nearer it is. As
it is, the image of the bow is clear only in the
distance ; it is lost as it begins to approach.
I do not agree with this argument in refutation,
though I approve the main sentiment which
it supports. And I will tell you why. The
cloud is coloured, but in such a way that the
colour cannot be seen from every point. And no
more can the cloud itself : for no one who is in it

n can see it. What wonder, then, if its colour cannot
be seen by one to whom itself is not visible ? And
yet, although the cloud is not seen, it is there : and
so is the colour. It is, therefore, no proof of the
deceptiveness of the colour that it ceases to be

v REFLECTION 27

manifest when one approaches it. For, I repeat,
the same happens to the clouds themselves : they
are not all a sham merely because under certain
conditions they cease to be visible. Besides,

when you are told that the cloud is dyed by the sun,
it does not mean that that colour of his is mingled,
as it were, with a hard, firm, durable body, but
with a liquid unstable body that is incapable of more
than a very brief impress. Let me add that there 12
are certain artificial colours which display their
virtue at a distance. The better and richer the
Tyrian purple is, the higher up you must hold it to
display its full blaze. It does not cease to possess
its colour simply because it does not reveal its best
shade in any and every position in which it is
exhibited. I am -of the same opinion as

Posidonius in holding that the bow is formed in a
cloud shaped like a hollow round mirror, whose form
is that of a section through a ball. This cannot be 13
proved without the aid of geometry : the mathe-
matical proofs leave no doubt that the bow is an
image of the sun, but one that does not resemble it.
Nor, indeed, are all objects faithfully represented in
mirrors. There are some mirrors one is terrified to
let one's eyes rest upon, such is the misshapen
and distorted image they reproduce of those who
gaze upon them. They deform the likeness they
preserve withal. Some, again, there are, a glance at i*
which causes great self-satisfaction in one's strength :
the arms are enormously increased, and the appear-
ance of the whole body is enlarged to superhuman
proportions. There are mirrors that turn faces to
the right, and mirrors that turn them to the left,
others twist and even invert them. What wonder,
then, that a mirror of this kind should be formed in

28 PHYSICAL SCIENCE BK. i

a cloud by which a defective appearance of the sun
should be presented ?

VI

1 AMONG the other arguments it must be mentioned
that a rainbow never is seen greater than a semi-
circle : the higher the sun is, too, the smaller is the
bow. As our countryman Virgil says :

And deep drinks
The mighty bow,

when rain is brewing. But the threat the bow con-
veys is not the same whatever the quarter it has

2 shown itself in. If it rises toward the south, it will
bring a heavy fall. The rain in that quarter, such is
its force, cannot be mastered by the strongest midday
sun. If it shine toward the west, there will be only
a dew or a light rain. If it rise in the east or there-
abouts, it prognosticates fine weather. If,
however, the bow is the sun's reflection, why does
it appear of far larger size than the sun himself?
Just because there is a kind of mirror that exhibits
objects on a far larger scale than that on which
they are presented to it, increasing their form to a
portentous magnitude : and in turn there is another
kind that reduces the size. And tell me this again,
why does an image assume the form of a circle if

3 it does not answer to a circle ? You may, perhaps,
tell me why the colour of the bow is varied : why
its shape is what it is, you will not be able to tell
me except by citing some model after which it is
formed. Now, other model there is none save that
of the sun ; when you admit that the rainbow
receives its colour from him, it follows that it

vi SIZE AND SHAPE OF BOW 29

receives its shape also from him. In short, you and
I are agreed that those colours by which its quarter
of the heaven is adorned proceed from the sun.
But on one point we are not agreed : you say that
the colour is real ; I maintain that it is only
apparent. Whichever it is, real or apparent, it
comes from the sun. On your assumption its
sudden cessation cannot be explained, seeing that
all other bright lights in the sky are dispelled
gradually. Its sudden appearance and, at the same 4
time, its sudden extinction make for my contention.
For it is a peculiarity of a mirror that the reflection
in it is not built up piecemeal, but all at once comes
fully into being. Every image in it is destroyed,
too, with as great rapidity as it was formed. For to
the construction or removal of the images nothing
is required but the presentation and withdrawal of
the objects.

In the rainbow-cloud whose nature is in ques-
tion, there is no proper substance or material :
there is only a sham and a likeness without
reality. Will you be convinced that this is so? 5
The proof is, the rainbow will cease if you conceal
the sun. Place another cloud, I repeat, in front of
the sun, and ^ all the bright hues of the bow are
gone. But what is to be said, you may ask,

in explanation of the size of the bow which is con-
siderably greater than that of the sun ? I have
already said that there are certain mirrors that
multiply every object they reflect. I may now add
that every object much exceeds its natural size when
seen through water. Letters, however small and
dim, are comparatively large and distinct when
seen through a glass globe filled with water.
Apples floating in a glass vessel seem more beauti-

30 PHYSICAL SCIENCE BK. i

6 ful than they are in reality. The stars appear
bigger if seen through a cloud, because our vision
is blurred in the moisture, and cannot accurately
grasp its object. This will become plain to demon-
stration if you fill a cup with water and throw a
ring into it. While the ring lies right at the bottom
its appearance is visible on the surface of the

7 water. Anything, in fact, that is seen through
moisture appears far larger than in reality it is.
What wonder that the image of the sun, being
seen in a moist cloud, should be reproduced on a
scale larger than the original, and that for the two
reasons indicated ? The cloud contains the two
elements, one like glass, which can transmit light,
and one also of the character of water ; at any rate,
if it does not just yet contain the actual water, it
is now forming it, its nature is already such as can
easily be changed into water.

VII

1 As you have mentioned glass, some one inter-
poses, I can draw from this same material an
argument to confute you. Glass sticks are manu-
factured, either fluted or bulging-,1 with many
corners like a club. If one of these sticks is placed
obliquely in the path of the sun's rays, it sends
back the colour which is wont to be seen in the
rainbow. This proves that there is not here an
image of the sun, but an imitation of his colour

2 from reflection. Now, in this argument there are
many points that make for my view. First of all,
it is plain that there must be some smooth surface
like a mirror to reflect the sun. Secondly, it is

1 Another reading gives "twisted."

vii PRISMATIC EFFECTS 31

plain that no colour is formed in the rod, but only
a false appearance of colour, such as I mentioned
above, which the neck of a pigeon, as it is bent
hither and thither, alternately puts on and off.
This, I say, is seen likewise in the case of a mirror,
which assumes no real colour, but only a certain
imitation of the colour of a foreign body.

Still, this one point requires explanation ; it is 3
not the sun's image that is beheld in that glass
stick, because it is not capable of expressing it
accurately. True enough it tries to reproduce the
image, because the material is smooth and suitable
for this purpose. But it fails because its shape is
unsymmetrical. If it had been suitably constructed,
it would reflect as many images of the sun as it
had faces. But since the sides are not distinctly
separated from each other, and not bright enough
to serve as mirrors, the images are only incipient,
not fully expressed ; they get confused through
being crowded together, and are reduced to the
appearance of a single band of colour.

VIII

BUT to return — why does the bow not complete
the full circle in its form, but appear as only a semi-
circle when stretched to the full extent of its
greatest span ? Some are of opinion that the
reason is that the sun, being much higher than the
clouds, strikes them only on the upper side. Hence
their lower parts are not touched by his light.
Receiving the sun only on one side, the clouds
reproduce only one portion of him, and this is
never more than a half. There is very little force

32 PHYSICAL SCIENCE UK. i

2 in this contention. My reason for saying so ? The
sun, even though he is on the upper side, yet
strikes, and therefore colours, the whole cloud.
How could it be otherwise ? His rays are wont
to be transmitted through the clouds and to
penetrate any density in them. Further, the proof
they advance is flatly in opposition to their main
proposition. For if the sun is higher than the
clouds, and his beams, therefore, shed only on their
upper side, the bow would never come down as far

3 as the earth. Yet it does descend to the very
ground. Besides, the bow is never seen except
opposite to, not below, the sun. The fact is, the
sun's highness or lowness does not affect the
matter : the side of the cloud that faces him is
struck by him throughout its whole extent.

Furthermore, sometimes even the setting sun
produces a rainbow ; surely at that time, being near1
the earth, he strikes the clouds on their lower side.
And yet then, too, the bow is only a semicircle, though
the clouds receive the sunlight on their lower and

4 darker portions. The Stoics, who hold that the
light is reflected in the cloud as in a mirror, make
the cloud hollow like the section of a ball. Such a
mirror, being but part of a circle, cannot, they
think, reproduce a whole circle. I give my adherence
to the proposition, but I cannot agree to the
argument in its support. For, if the whole figure
of a1 circle placed opposite a concave mirror is
reproduced in it, then there can surely be nothing to
prevent the whole of a ball being seen in a semi-

5 circular mirror. Besides, we have already shown that
complete rings resembling a rainbow surround the

1 The common reading makes this adjective refer to clouds — the clouds
which are near the earth.

vin SEASONS OF RAINBOW 33

sun and the moon at times. Why should the circle
be complete in the halo, but never in the rainbow ?
And then again, why should the clouds that receive
the sunlight be always hollow ones, and not some-
times flat or bulging ?

Aristotle says that rainbows are formed, after the
autumnal equinox, at any hour of the day, but in
summer only either in the early part of the day, or
when the sun has begun to sink. The cause of this
is obvious. In the first place, about midday the great 6
heat of the sun dispels the clouds : he cannot be
reflected in the clouds which he breaks up. But
in the early morning and as he sinks toward the west,
his rays have less power, and can thus be resisted
and reflected by the clouds. In the second place,
the sun is not wont to form a bow except when he
faces the clouds in which it is formed. When the ^
days are shortening in autumn, his rays are always
slanting. Therefore, he has some clouds facing him
that he can strike, at any part of the day, even at
the hour at which he attains his meridian height.
But in the summer season he sails right overhead.
Therefore, in the great altitude of his midday
course, he looks down on the earth too directly to
encounter any clouds. He has them at that period
all beneath him.

IX

I MUST now go on to speak of Streaks (watergalls, i
sun-dogs), which are as bright and varied as the
rainbow, and commonly received by us as equally
indicative of rain. No great labour need be spent
in explaining them, for they are just incomplete 2
rainbows. They have the variegated appearance

34 PHYSICAL SCIENCE BK. i

of the bow, but none of its curve. They lie in
a straight line. They are formed near the sun,
as a rule, in a moist cloud that has begun to break
up. Thus, they have the same colour as is found
in the rainbow, but there is a difference in the
shape, due to the corresponding difference in the
clouds over which they stretch.

THERE is a similar variety of colours in Halos.
But there is this difference in the various pheno-
mena : Halos are formed at any point in the sky,
wherever there is a heavenly body ; rainbows are
not found except opposite the sun ; streaks, only
in the neighbourhood of the sun. I may express
their difference in another way : Bisect a halo and
you have a rainbow ; make it a straight line and
you have a streak. In all three there is the same
multiplicity of colours, the scale running from dark
blue to orange. Streaks, then, are found only close
to the sun. Rainbows are all either solar or lunar.
Halos are seen with all the heavenly bodies.

XI

1 ANOTHER kind of streak is visible when thin rays
of bright light equidistant from one another are shot
out through narrow apertures in the clouds. These,
too, are a prognostication of rain. How am I to
express myself here ? What shall I call them ?
Images of the sun ? The chroniclers call them
merely suns, and have put on record that they have

2 been seen in twos and threes. The Greeks call

MOCK SUNS 35

them Mock Suns (parelia = beside the sun), because
they are generally seen in proximity to the sun,
and somewhat resemble the sun. They do not
give a complete reproduction of the sun, but ex-
hibit only his size and shape. They are dull,
however, and languid without any of his heat.
What name are we to apply to them ? Shall I do
as Virgil did — hesitating about the name, employ
the very name which causes the hesitation ?

And by what name l shall I call you,

Rhaetian wine? But yet you must not seek to compete with
the Falernian bins.

There is no objection to my calling these, mock
suns. They are, in fact, images of the sun formed
in a thick cloud close to him after the fashion of a
mirror. Some writers define a mock sun as a cloud,
round, bright, and resembling the sun. The mock
sun follows the sun, and is never left farther behind
him in his orbit than it was at its first appearance.
None of us, I suppose, is surprised at seeing a
reflection of the sun in some fountain or quiet lake.
Well, his disc may be reflected in the heavens just
as readily as on earth, if only the material is suitable
to produce the reflection.

• XII

WHENEVER we wish to observe an eclipse of the
sun, we place on the ground basins filled with oil
or pitch. The thick liquid is not easily disturbed,
and therefore retains the images it receives.
Images, I may observe, cannot be seen except in a

1 He has altered Virgil's word "carmine" to "nomine" to suit his
meaning, or, as the editors say, lapsu memoriae.

36 PHYSICAL SCIENCE BK. i

liquid at rest. Then we are in the habit of noting
how the moon obstructs the sun, and by the inter-
position of her body hides his, which is so much larger,
sometimes partially, if it so fall out that she only
encounter a portion of his orb, sometimes completely.
2 The latter is called a total eclipse : it quite shuts
out the light and shows us the stars ; it occurs when
the centre of the two bodies lies in the same straight
line. Now, just as the image of both sun and moon
can be seen on earth, so it is in the case of mock
suns in the atmosphere. The still air is so compact
and yet clear that it can receive the sun's likeness.
Other clouds receive it, but let it go if they are
either in motion, or thin, or black. The moving
clouds disperse it, the rare let it slip, the black and
impure do not take the impress of it, just as on
earth soiled objects do not reflect an image.

XIII

1 MOCK suns are wont to be formed in pairs and on
the same principle. There is nothing, in fact, to
prevent the formation of as many as there are clouds
suitable for exhibiting an image of the sun. Some
writers are inclined to hold that when two such
phantoms are visible, one arises directly from the
sun, the other from his image. For, to use an
illustration from common experience, when several
mirrors are so arranged that one is in sight of the
other, all reflect the same image ; but only one is
directly from the original, the rest are reflections

2 of images. The nature of the object presented to
the mirror makes no difference in the effect. What-
ever it sees it reproduces. So, up on high there, if

THEIR CAUSE 37

some chance has so disposed the clouds that they
face one another, one of them reflects the image of
the sun, the other the image of his image. The
clouds that produce this effect must be dense,
smooth, bright and flat, analogous in character to
the sun. All phantoms of this kind are white and
resemble so many discs of the moon, for the reason
that the sun's light that they receive and reflect
back is always oblique. If the cloud, on the con- 3
trary, is beneath the sun and too near him, his rays
dispel it : or again, if situated too far away, it does
not reflect them nor produce any image. In
ordinary experience in the same way mirrors with-
drawn to a distance from us do not reproduce our
features because our sight cannot carry back to us
from them.

These suns, too — to employ the name given by
the chroniclers, — are an indication of rain, especially
if they have their position in a southern quarter,
from which the most heavily-charged clouds chiefly
come up. When such an image surrounds the sun
on both sides, then, if we are to believe Aratus,
a storm is brewing.

XIV

IT is now high time- that I ran over the other i
varieties of celestial fires, whose forms are diverse
one from the other. Sometimes there is a shooting
star, sometimes there are glowing lights, which are
occasionally stationary, sticking to one spot, and at
times able to rush through the air. Several species
of these may be observed. There are, for example,
Bothynae (cave -like meteors) when within an
outer circle there is a blazing gulf in the sky like a

38 PHYSICAL SCIENCE BK. i

circular grotto excavated in it. Then there are
Pithitae (barrel-shaped meteors) when a vast circular
mass of fire like a cask either rushes through the

2 sky, or blazes away in one spot. There are
Chasmata (chasms), too, when there is a subsidence
of some portion of the heavens, which sends out
hissing flame, as it were, from its hidden recesses.
There are also a great number of colours in all
these. Some are of brightest red, some of light
insubstantial flame, some of white light, some
glittering, some with a uniform glow of orange
without sparks or rays. We see, therefore,

The stars' long tracks that gleam white behind.

3 These stars, for so they appear to be, dart forth
and flit across the sky, and by reason of their
extraordinary rapidity seem to leave a long trail
of fire. Our sight cannot follow their course, and
wherever their career leads we imagine the heaven
is all on fire. Such is the swiftness of their flight
that its separate portions are not distinguished
and it can be grasped only as a whole. We are
aware rather of the quarter in which the star

4 appears than of its route. It, therefore, seems to
mark its entire course with a line of continuous
fire, because the slowness of our vision fails to keep
pace with the stages of its career and sees at the
same moment the start and the finish ; as happens
in a flash of lightning, the fire seems a long train
because the meteor traverses its path rapidly and
the space through which it falls presents itself to
our eyes as a whole. But, as a matter of fact, the
fire does not extend itself all through the space

5 crossed by the meteor. Nor have such long thin
bodies strength enough for the effort. How, then,

xiv OTHER CELESTIAL FIRES 39

it may be asked, do they issue forth ? The answer
is, the fire is kindled by the friction of the atmosphere
and is urged headlong by the wind. Still, it does
not always arise from wind or friction. Some-
times its origin is due to certain peculiar conditions
in the atmosphere ; for on high there are many
elements, dry and hot and earthy, among which fire
is generated. It then streams down in pursuit of
fuel to sustain it, and therefore is hurried rapidly
along. The reason for the differences of colour it 6
presents lies in the nature of the material set on
fire and in the degree of violence of the conflagra-
tion. A falling body of this kind betokens wind,
which may be looked for in the quarter in which
the meteor has burst out.

XV

How, some one further inquires, are those bright i
gleams of light which the Greeks call Sela (lumin-
osities) produced ? In many ways, people say.
They may arise from the violence of the winds,
or from the fervent heat of the upper heavens.
Fire is a very widely diffused element there, and
sometimes catches the lower regions if they are
combustible. The mere motion of the stars in
their courses may kindle fire, and convey it
to all that lies beneath them. Nay, is it not
quite possible that the atmosphere should drive up
even to the ether the germs of fire, from which may
arise a glow or burning or darting resembling a
star ? Some of these gleams rush headlong like 2
shooting stars, some remain fixed in their place,
emitting light sufficient to dispel darkness and re-

40 PHYSICAL SCIENCE BK. i

instate daylight, until their fuel is used up, and they
gradually grow dimmer, and by and by, just like a
flame which is dying out, are by gradual subsidence

3 reduced to nothingness. Some of these appear in
the clouds, some above them : in such cases the
thick air nearer the earth feeds them for a long time,
but eventually forces them right up to the stars.
Certain of these last no considerable time : they
straightway dart across the sky, or are extinguished
just at their point of origin. These are called
gleams because their appearance is fitful and short-
lived, though their fall is not always unattended by
injury : they have often caused as much damage as
lightning. One has seen houses struck by them,
what the Greeks call astrapoplecta * ( = star-struck).

4 Those that have a longer career and a stronger fire
which follows the motion of the heavens, or those
that pursue an orbit of their own, are regarded by
the Stoic philosophers as Comets : of which more
anon. Different kinds of these zxepogoniae (bearded),
lampades (torches), and cyparissiae (like cypress
trees), and all the rest of them : they have a thin
tail of fire. It is doubtful whether beams (trades)
and the rare barrel -meteors (pithitae) should be

5 placed in this category or not. Such meteors re-
quire a great mass of fire, since their immense orb
sometimes surpasses in size that of the morning sun.

Among these should certainly be placed a pheno-
menon of which we often read in the chronicles
— the heavens appeared to be on fire. The blaze
of it is occasionally so high as to mount to the very
stars ; occasionally it is so low as to present the

6 appearance of a distant fire. In the reign of

1 The term might also mean struck by lightning. A commoner reading
gives the meaning : which, when grazed by this means, the Greeks called
plecta ( = struck).

xv SUBSTANCE AND SHADOW 41

Tiberius Caesar the fire brigade hurried off to the
relief of the colony at Ostia, supposing it to be in
flames ; during the greater part of the night there
had been a dull glow in the sky, which appeared to
proceed from a thick smoky fire. No one has any
doubt that these burnings in the heavens contain
flame as really as they display it : they have a
certain substance in them. As to those for- 7

merly discussed, I mean rainbows and halos, it is a
question whether they deceive the sight and consist
of an illusion ; or really contain what appears in
them. I and those who think with me cannot con-
vince ourselves that the rainbow and halo have a
basis of any definite material in them. For we judge
that in a mirror there is nothing but a deception :
the mirror only pretends to show a foreign body.
What is revealed does not exist in the mirror. 8
Otherwise it would not come out of it, nor would it
be forthwith obscured by another image : nor would
innumerable forms now fade from it, now be received
by it. What follows, then ? That these are mere
phantoms and the insubstantial imitation of real
bodies. Indeed, in certain instances, people have so
arranged mirrors that the objects have been distorted
and degraded in the reflection. For, as I have already
said, there are some mirrors that twist the faces of
those who look into them, some that enormously
increase them until they exceed all size and propor-
tions of these bodies of ours.

XVI

AT this point I wish to tell you a little story
to show you how unscrupulous lust is in seizing

42 'PHYSICAL SCIENCE BK. i

every instrument that will rouse passion : so re-
sourceful is it in goading to madness its own morbid
fury. There was one Hostius Quadra whose
obscenity formed a model for everything that was
lewd on the stage. He was rich and avaricious, a
very slave to his millions. He was eventually
murdered by his own slaves, but the late Emperor
Augustus considered his murder undeserving of
punishment, and as good as declared that he had

2 been justly slain. This man's lust knew no distinc-
tion of sex. Among other things, he had mirrors
constructed of the kind just mentioned, that re-
flected images of abnormal size, causing, for ex-
ample, a finger to exceed the size of an arm in
length and thickness. He so arranged his mirrors
that he. could see all his accomplices' movements,
and could gloat over the imagined proportions

3 of his own body. He raised a levy of scamps
like himself in all the public baths, where he chose
men of the regulation height ; this but whetted his
appetite to have his scenes of riot reproduced in
false unnatural proportions. Go to, you that say
the mirror was invented for purposes of adornment I
I could not soil my pen by recording the foul words
and deeds of that monster : he deserved to be torn
by his own jaws. To aggravate his guilt, mirrors
faced him on every side that he might be a witness of

4 his own infamy. Deeds of darkness, which lie heavy
on the conscience, the imputation of which ordinary
men will indignantly spurn, weighed so lightly with
him that he thrust them before his face, and into
his very eyes. Crimes, in faith, usually dread the
sight of themselves. Even in those lost to shame,
and exposed to every insult, the eye is still delicately
susceptible. But that beast thought his unparalleled

xvi STORY OF HOSTIUS QUADRA 43

wickedness but a trifle ; he summoned his eyes to
witness it. Aye, not content with seeing his sin, he
surrounded himself with mirrors to multiply and
group his scenes of vice. Even when he could not 5
see directly, he employed the reflecting power of
the mirrors to reveal scenes of revolting and abomi-
nable iniquity. The filthy blackguard left nothing 6
that could be called a deed of darkness. He had no
dread of the daylight, but complacently applauded
himself in all his bestial vice. Now, don't you
think he would have liked to have his portrait
painted in that attitude ? The ministers of public
vice draw the veil of modesty over them in part :
in fact, a house of ill-fame is in some degree shame-
faced. But that brute had made an exhibition of 7
his obscenity, and presented to his own sight what
the darkest night is not deep enough to hide. I will be
out and out bad, was the monster's resolve ; my eyes
must share my lust, they must witness and super-
intend ! By my art I will defeat nature's shyness : g
nobody must imagine that I do not know what I am
about ! Nature is niggardly to man, she is more
generous to the cattle. I will find means to thwart
her, and to indulge my little weakness. My lust
shall go one better than nature. I will construct a
mirrored chamber that will reflect shapes of enor-
mous size. I only wish I could make the size real ; 9
but I must be content with the belief of it. My
vice must see more than it can compass, and must
rest content with wonder at its own restraint.

Away with such a fellow ! Perchance he met a
speedy death even before he could gloat over the
sight. He richly deserved to be offered up as a
victim before his own mirror-idol.

44 PHYSICAL SCIENCE

XVII

1 Go now and laugh at the philosophers for discussing
the nature of the mirror and inquiring why our face
is reflected in it, and is turned toward us too. What
did nature mean by giving us real bodies and then
ordaining that phantoms of them also should be
visible ? What was her purpose in providing
material of the sort capable of receiving and return-

2 ing images ? Not, I trow, that we men might
use a looking-glass to pluck out the straggling
hairs of our beard and polish up our face.
Nature has never at any point merely provided
resources for luxury. First of all, her motive was
to show us the sun with his glare dulled, since
our eyes are too weak to gaze at him direct, and
without something to reflect him we should be

3 wholly ignorant of his shape. No doubt one may
study him as he rises and as he sets. But we should
know nothing of his true figure as he shines in
fierce noonday brightness, without his softening
ruddy glow, unless an image of him could be
mirrored in some liquid where he shines less
directly and is more easy to observe. In the second
place, we should be unable to see or investigate
the conjunction of two heavenly bodies, by which
the daylight is wont to be interrupted, unless we
could examine the reflections of sun and moon
in basins on the ground with comparative freedom.

4 In the third place, mirrors were discovered in order
that man might come to know himself.

Many benefits have ensued ; first, the knowledge
of self, after that, devices to secure specific results.
The comely man was taught to shun conduct that

xvn EVOLUTION OF THE MIRROR 45

would degrade him. The uncomely learned that
bodily defects must be compensated by virtue of
character. The young man was reminded by his
vigour that youth was the time for learning and for
performing daring deeds of chivalry. The grey-beard
was warned to have respect for his hoary hair and
turn his thoughts sometimes to death. It was for 5
this that even objects in nature have afforded us the
opportunity of seeing ourselves.1 A clear fountain
or a smooth stone gives each back his image. In
the poet's words :

Lately I saw myself on the shore,
When the sea stood calm without a breath of wind.

What, think you, was the style of life of the people
who dressed at a mirror of this kin$ ? The age was
unsophisticated, satisfied with what supplies chance
presented. It did not as yet degrade a boon into a
vice, or turn nature's invention to purposes of lust
and luxury. At first, chance revealed to each his 6
form. In due time the inherent self-love of man-
kind endeared the sight of their own figure, and
they came to look more frequently into the mirror
held up by nature in which they had first beheld
their image. Later on, when a worse race of men
ransacked the very bowels of the earth for treasure
better hid more deeply, iron first came into use ;
its production might have caused no damage had
the world produced only that one metal. But then ^
in good earnest were brought to light the other
precious banes of earth. Their smooth surface
presented the image of their possessors, who had
in view some quite different purpose. One saw his

1 The meaning may be, In addition, i.e. to artificial mirrors, objects in
nature, etc.

46 PHYSICAL SCIENCE BK. i

reflection in a cup, another in a brass vessel pro-
cured for some ordinary use. Presently a round
mirror was constructed specially to render this
service : it was not as yet of polished silver, but of
a common brittle ware.

The men of ancient days lived a homely life ; they
thought themselves smart enough if they washed off
in the stream of the river the dirt contracted in their
work. But even then they bestowed pains on dress-
ing their hair and combing out their flowing beards.

s In this part of the toilet each attended to himself and
at the same time helped his neighbour. The thick
streaming hair of the men, which it was of old the
fashion to wear, was, of course, combed out by the
wives. But sometimes they thought themselves
handsome enough without any such artistic hand,
and they just shook it out for themselves as spirited
animals do their mane. Afterwards, when luxury
had now gained sway, embossed mirrors of gold and
silver of full-length size were made, and at last they
were actually adorned with precious stones. One
of these has ere now cost a woman more than the
amount of a dowry given in the old days at the
public expense to the penniless daughters of famous

9 generals. Do you suppose Scipio's daughters bought
mirrors chased with gold from the iron money
that their dowry was paid in? Happy the poverty
that gave occasion to earn such a title to glory !
The Senate would not have dowered them if they
had been able to afford mirrors. Whoever the
man was to whom the Senate acted the part of
father-in-law, he knew that he had got a wife that
was above suspicion. Nowadays the whole of the
dowry that the Roman people gave Scipio would
not be enough to buy a single looking-glass for

xvn AN INSTR UMENT OF LUXURY 47

some of the loose, silly daughters of our freedmen !
Luxury has been gradually developed merely by
the possession of wealth, and has now gone to
oppressive lengths ; therewith vices have received
an immense accession of strength. In short, every-
thing has got so mixed up through our perverted
refinements that all that used to be regarded as
the decoration of women has become part and
parcel of the outfit of man ; I am understating,
it is now an essential portion of a soldier's kit.
The mirror was introduced for the sake of the toilet ;
nowadays there is no vice to which it is not an
indispensable adjunct.

BOOK II

[THE NATURE OF AIR. THUNDER AND
LIGHTNING]

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. n

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 MATTER 53

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).

'- That is, are not composite.

54 PHYSICAL SCIENCE

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. \
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] l 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

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;

1 ireplffTa.ffis = 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.

vni 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 hand1 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 LAYERS OF ATMOSPHERE 61

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 r
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
2 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 —

xii THUNDER AND LIGHTNING 63

some authorities believe that the fire is actually
resident in the clouds, some that it is merely pro-
duced fcr 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 UK. 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 wre 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 haye 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

7o 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] l 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. n

force as launched the bolt from the cloud causes it
2 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

i 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. 11

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.

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. n

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

i 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

xxxii 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 l 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

1 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

2 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,

9o

PHYSICAL SCIENCE

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.

JOVE'S BOLTS 91

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 1 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 clas"s, 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
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
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 CAUSE 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.

PHYSICAL SCIENCE

LVI

1 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,

2 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

RAREFACTION AND FRICTION

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 i
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 2
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 ?

104 PHYSICAL SCIENCE BK. n

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.

BOOK III

WHICH TREATS OF THE DIFFERENT
FORMS OF WATER

107

PREFACE

I AM not unaware, my dear friend Lucilius, of the i
greatness of the edifice whose foundations I am
laying in my old age, when I resolve to survey the
universe, to unearth its motives and secrets, and to
reveal them to the knowledge of others. When shall
I ever manage to cover such a field, gather together
such widely-spread material, behold with clear vision
such profound secrets ? Old age presses hard on
the rear, upbraiding me with the years bestowed on
vain pursuits. We must ply our task all the more
vigorously, and toil must now make good the loss
of a lifetime withdrawn from its true purpose.
Night must be added to day, engagements cut 2
short, care abandoned of property that lies far away
from its owner. The mind must be wholly set free
from other thoughts, and at least at the moment of
its flight from earth must bestow itself in self-con-
templation. It shall do so, and shall urge itself on,
and each day it shall measure the brief span of time
left. What has been lost shall be repaired by diligent
use of the remainder of life. The surest pledge of
virtue is repentance and amendment. I may ex- s
claim in the words of an illustrious poet :

High is the courage that inspires me, great the work, but short
The time in which to plan.

109

PHYSICAL SCIENCE

I should say the same were I planning it in boyhood
or in youth. No period could be anything but
narrow in face of such an undertaking. As it is,
when the midday of life is past, I have entered upon

4 a task that is serious, difficult, limitless. Let me
act as people generally do in a journey — those that
are late in starting make up for the delay by their
speed. I must hurry on, and without further excuse
on the score of age proceed to tackle my problem
— undoubtedly a vast, possibly an insuperable, one.
My mind swells with pride when I survey the
magnitude of my undertaking and reflect how much
is unaccomplished of my plan, though not of my
life.

5 Some writers have wasted their efforts in nar-
rating the doings of foreign kings, and in telling,
as the case may be, the sufferings or the cruelties
of nations. Surely it is wiser to try to end one's
own ills than to record for a coming generation the
ills of others. How much better to make one's
theme the works of the gods than the robberies of
Philip, or Alexander, or the other conquerors who
earned their fame by the destruction of mankind !
Such men were as truly scourges of humanity as a
flood by which a whole plain has been inundated, or
a conflagration by which the greater part of its

6 living creatures has been burnt up. The historians
tell us how Hannibal crossed the Alps, how he sud-
denly transferred into Italy a war rendered more
formidable by Roman disasters in Spain ; how,
when his fortunes were shattered, more determined
still, even though the fate of Carthage was sealed,
he wandered through all kingdoms, offering to be
leader against Rome, and begging for an army ;
how he never ceased even in his old age to seek

PREF. PHILOSOPHY VERSUS HISTORY m

to rouse up war in every corner of the world.
He could, it was plain, endure to be without a
country, but not without a foe.

How much better is it to inquire what ought to 7
be done than what has been done, and to teach
those who have entrusted their state to fortune that
nothing she gives is stable, but that all her gifts are
more fickle than the very air ! For she cannot rest,
her delight is to match sadness with joy, and to
mingle smiles with tears. Therefore in the day of
prosperity let no man exult, in the day of adversity
let no man faint : the successions of fortune alter-
nate. Why should you boast yourself ? The wave 8
meantime bears you aloft on its crest ; but where it
may strand you, you cannot tell. Its end will be
of its own choice, not of yours. Or why, again, do
you despond? You have been carried down to
the nadir ; now is the chance of rising again.
Adversity alters for the better, success for the worse.
Changes of the kind must be anticipated, not merely
in private families, which are affected by a slight
cause, but also in sovereign houses. Dynasties
rising from the gutter have ere now established
themselves above the ruling powers, while ancient 9
empires have fallen when in the very heyday of
their power. The number cannot be reckoned of
the kingdoms that have been overthrown by other
kingdoms. God now makes it His special aim to
exalt some and to overthrow others ; nor does He
let them gently down, but dashes them from their
pinnacle, so that no remnant of them is left. A
great sight it is ; we think it so only because we
are ourselves small. There are many departments 10
in which the standard is not derived from the actual
size of the objects, but from our own littleness.

PHYSICAL SCIENCE

What, I ask, then, is the principal thing in human
life ? Not to have filled the seas with fleets, nor to
have planted the standard of the nation on the shores
of the Red Sea, nor, when land has been exhausted,
to have wandered for the injury of others over the
Ocean in quest of the unknown. Rather it is to have
grasped in mind the whole universe, and to have
gained what is the greatest of all victories, the mastery
over besetting sins. There are hosts of conquerors
who have had cities and nations under their power,
but a very few who have subdued self. What is
the principal thing ? I say again. To raise the
soul above the threats and promises of fortune ; to

11 consider nothing as worth hoping for. For what
does fortune possess worth setting your heart upon ?
Why, as often as you lapse from converse with what
is divine back to what is human, your eyes will be
blinded just like the eyes of those who have returned
from bright sunlight into gross darkness. What is
the principal thing ? To be able to endure adver-
sity with joyful heart ; to bear whatever betide just
as if it were the very thing you desired to happen.
For you would have felt it your duty to desire it, had
you known that all things happen by God's decree.

12 Tears, complaints, lamentation, are rebellion. What
is the principal thing ? A heart in face of calamity
resolute and invincible ; an adversary, yea, a sworn
foe, to luxury ; neither anxious to meet nor anxious
to shun peril ; a heart that knows how to fashion
fortune to its will without waiting for her ; which
can go forth to face ill or good dauntless and un-
embarrassed, paralysed neither by the tumult of the

13 one nor the glamour of the other. What is the
principal thing ? Not to admit evil counsel into the
heart, and to lift up clean hands to heaven ; to seek

PREF. THE PRINCIPAL THING 113

for no advantage which some one must give and
some one lose in order that it may reach you ; to
pray — a prayer that no one will envy — for purity
of heart; as for other blessings which are highly
esteemed by the world, even should some chance
bring them to your home, to regard them as sure to
depart by the same door by which they entered.
What is the principal thing ? To lift one's courage 14
high above all that depends upon chance ; to re-
member what man is, so that whether you be
fortunate, you may know that this will not be for
long ; or whether you be unfortunate, you may be
sure you are not so if you do not think yourself so.

The principal thing is to have life on the very
lips, ready to issue when summoned. This makes a
man free, not by right of Roman citizenship, but by
right of nature. He is the true freeman who has
escaped from bondage to self. That slavery is
constant, from it there is no deliverance ; it presses
us day and night alike, without pause, without
respite. To be a slave to self is the most grievous 15
kind of slavery ; yet its fetters may easily be struck
off, if you will but cease to make large demands
upon yourself, if you will cease to seek a personal
reward for your services, and if you will set clearly
before you your nature and your time of life, even
though it be the bloom of youth ; if you will say to
yourself, Why do -I rave, and pant, and sweat ?
Why do I ply the earth ? why do I haunt the forum ?
Man needs but little, nor needs that little long.

To this end it will be profitable for us to examine
the nature of the universe. In the first place we
shall rise above what is base ; in the second, we shall
set the spirit free from the body, imparting to it that
courage and elevation of which it stands in need.

u4 PHYSICAL SCIENCE BK. m

16 Besides, subtlety of thought practised on the
hidden mysteries of nature will prove no less
efficacious in problems that lie more on the surface.
And nothing is more on the surface than these
salutary lessons we are taught as safeguards against
the prevailing vice and madness — faults we all con-
demn, but do not abandon.

1 LET us enter then on an investigation of forms
of water, and let us trace the causes that produce
them ; whether, as Ovid says :

There was a fountain silvery clear with gleaming wavelets ;

or, as Virgil says :

Whence through nine mouths with mighty roar of the mountain
The sea issues in broken waves, overspreading the fields with its
resounding flood ;

or, as I find it in your own poem, my dear Lucilius :
The stream of Elis wells up from Sicilian fountains.

Let us inquire by what method the waters are

2 supplied ; how it is that day and night unceasingly
so many huge rivers roll down their course ; why
some are swollen by the rain of winter, some
increase in summer when all the other streams fail.
Meantime let us separate the Nile from the common
crowd ; it is a river of peculiar and unique character.
We shall give it its turn by and by. At present we
will confine our treatment to the common waters,
cold as well as hot. In regard to the latter we
must inquire whether the heat is due to natural or
artificial causes. We shall discuss other waters
too which are rendered remarkable by taste or some

i FORMS OF WATER 115

special virtue. Some, for example, I may explain,
alleviate affections of the eyes, some, those of the
sinews, some effect complete cure of chronic maladies
given up by doctors as hopeless. Some again heal
sores, some by being drunk ease internal pain and
relieve complaints of the lungs and bowels. Some
staunch the flow of blood ; in fact their individual
uses are as varied as their taste.

II

ALL waters are classed as either standing or
running ; they are either gathered in one or occupy
different channels underground. Some of them are
sweet, others have pungent flavours of different
kinds, among them salt, bitter, medicinal. Belong-
ing to the last class one may name sulphur, iron,
alum waters. The taste shows the quality. Waters
of different kinds have many other differences.
First there is touch, hot and cold; then weight,
light and heavy ; then colour, pure, muddy, dark
blue, yellowish ; then wholesomeness, wholesome
and useful, or deadly or capable of petrifaction.
Some waters are thin, some thick ; some give
nourishment, others pass through the system with-
out benefiting it at all ; the use of some removes
barrenness.

Ill

THE lie of the ground makes water either stand or
run ; on a slope it flows down, a plain keeps it
in, causing it to stagnate. Sometimes under pres-
sure of air it is forced uphill ; it is then driven, it

n6 PHYSICAL SCIENCE BK. m

does not flow. Surface water comes from rain ;
spring water from a natural fountain. There is,
however, nothing to prevent surface and spring
water in the same spot. This we see in Lake
Fucinus, into which the streams drain all the
rainfall of the surrounding mountains, while there
are also large springs concealed under the surface
of the lake itself. So, even when the torrents
discharge into it in winter, it preserves its appear-
ance unaltered.

IV

LET us inquire therefore, in the first place, how the
earth can contain sufficient water to maintain the
unbroken flow of the rivers, and where such a vast
quantity of water comes from. We are surprised
that the ocean is not sensible of the additional water
derived from rivers. It is no less surprising that
the earth is not sensible of the loss of all the water
that issues from it. What is it that has so filled it
up that it can from its hidden recesses furnish such
quantities and continually make good the loss as
it does ? Whatever explanation we give regarding
a river must apply also to streams and springs.

SOME are of opinion that, the earth receives back
all the water it has lost. The sea, therefore, does
not get larger, because it does not assimilate the
water that runs into it, but forthwith restores it to the
earth. For the sea water returns by a secret path,

v EARTH'S RESERVOIR 117

and is filtered in its passage back.1 Being dashed
about as it passes through the endless, winding
channels in the ground, it loses its salinity, and,
purged of its bitterness in such a variety of ground
as it passes through, it eventually changes into pure,
fresh water.

VI

SOME suppose that all the water that the earth
drinks in from rain is sent out again into the
rivers. They set down by way of proof the fact
that there are fewest rivers in the localities where
there is least frequent rain. On that account, they
say, the deserts of Ethiopia are destitute of streams,
and few springs are found in the interior of Africa,
because there is always a blazing sky and almost
perpetual summer. Therefore there are ugly
stretches of sandy waste, without tree and without
inhabitant, sprinkled at rare intervals by showers
that they immediately swallow up. On the other
hand, it is well known that there are abundant
streams and rivers in Germany and Gaul and
next to them in Italy, because they enjoy a moist
climate, and even the summer is not without
rainfall.

VII

A GREAT deal can obviously be urged in reply to i
this. First of all, as a diligent digger among
my vines, I can affirm from observation that no

1 The .ordinary text, as Koeller saw, is evidently wrong. It runs : " For
by a secret path the sea water enters the ground and becomes visible, and
returns stealthily, and is filtered, etc." No author can be supposed to have
written such a sentence. The restoration must be conjectural. I have
adopted what seems simplest and most in keeping with the context.

n8 PHYSICAL SCIENCE UK. in

rain is ever so heavy as to wet the ground to a
depth of more than 10 feet. All the moisture is
absorbed in the upper layer of earth without getting
down to the lower ones. How, then, can rain, which
merely damps the surface, store up a supply sufficient
for rivers ? The greater part of it is carried off at
once into the sea by river-channels. But a small
portion is absorbed by the ground, and even that is

2 not retained. For the ground is either dry and
so uses up at once the water poured into it ; or else
it is saturated and throws off what of the rainfall
it does not require. This is the reason why rivers
do not rise with the first rainfall ; the thirsty ground
absorbs it all.

And then, again, how are we to explain the fact
that some rivers burst out from rocks and moun-
tains ? What contribution can be made to them by
rains that are carried down over the bare crags

3 and have no earth into which to sink ? Besides,
wells sunk in the very driest localities to a depth
of 200 or 300 feet reveal rich springs of water at
a depth to which rain water does not penetrate.
One may be sure there is no rain water there nor
any gathering of moisture, but living ( = spring)
water as it is usually called. The opinion in
question is disproved by this other argument, too ;
some springs well up in the very summit of a
mountain. It is plain, therefore, that the water in
them is forced up or forms on the spot, since all
the rain water runs off.

VIII

SOME writers think there is an exact parallelism
between the external and the internal distribution

viii SURFACE AND UNDERGROUND WATER 119

of water in the earth. On the outer surface are
huge marshes, great navigable lakes, and seas
covering immense tracts of earth and pouring over
its hollows. So in the interior of the earth there
is abundant store of fresh water, which overflows
great spaces no less than the Ocean and its gulfs
above ground ; in fact, still more extensively, as the
depth of the earth extends farther down than that
of the sea. From that supply in the deeps, there-
fore, those rivers of which we have spoken issue.
And why should one be surprised that the earth is
not sensible of their withdrawal since the sea is not
sensible of their addition ?

IX

SOME approve the following explanation : The i
earth contains, they assert, many hollow recesses
and a great quantity of air. This air, under pres-
sure of the gross darkness, of necessity freezes.
Then remaining sluggish and unmoved it ceases to
circulate and turns into water. Just as on earth a
change in the density of the atmosphere produces
rain, so beneath the earth the change of density
starts a river or a stream. In the former case the
air above our heads cannot long remain sluggish
and heavy ; for sometimes it is rarefied by the sun's
heat, sometimes expanded by the wind's force.
There are, therefore, long intervals between falls 2
of rain. But underground the forces, whatever they
are, that turn air into water, are constant — perpetual
darkness, everlasting cold, inert density ; they can,
therefore, supply without a break the sources of
fountain or flood. We Stoics are satisfied that the

120 PHYSICAL SCIENCE BK. m

earth is interchangeable in its elements. So all this
air that she has exhaled in her interior, since it is
not taken up by the free atmosphere, condenses and
is forthwith converted into moisture.

1 THERE you have the first cause of the origin of
underground water. You may add the more
general principle that all elements arise from all :
air comes from water, water from air ; fire from air,
air from fire. So why should not earth be formed
from water, and conversely water from earth? If
the earth is capable of transmutation into other
elements, water must be one of them, in fact, the
most suitable of them. The two things are cognate ;
both are heavy, condensed, both driven by nature
down to the very confines of the universe. Earth
is formed from water ; why not water from earth in
like manner?

But, you say, the rivers are too large to be
accounted for in this way. Well, after you have
considered the size of the rivers, just look at the

2 size of the reservoir whence they issue. Are you
surprised that a fresh supply of water is always
forthcoming for them, since they flow on for ever,
some even rushing down their channel with im-
petuous haste ? Surely you might as well be
surprised, when the winds drive hither and thither
the whole atmosphere, that the supply of air does
not fail, but flows on day and night unceasingly.
And the wind, remember, is not confined to a definite
channel, as rivers are, but goes with wide sweep
over the broad expanse of heaven. You might

ELEMENTS INTERCHANGEABLE 121

well, too, be surprised that after so many breakers
have spent their force, any succeeding wave is left.
The truth is, nothing is ever exhausted that returns 3
upon itself (i.e. is self-supported). All the four
elements return alternately upon one another ; what
is lost in one is conserved by passing into another.
Nature, too, weighs her parts as if with nice adjust-
ment in the balance, lest their just proportion should
be disturbed and the world topple over into ruin
( = lose its equilibrium). All elements are in all.
Air not only passes into fire, but it is never without
fire. Deprive it of its heat and it will grow stiff,
stagnant, hard. Air passes into moisture, but
nevertheless contains moisture. Earth yields both 4
air and water, and is never at any time devoid of
water any more than it is of air. 'The mutual
transition is the easier, because there is already an
admixture of the element to which the transition
is to be made. So (i),1 then, the earth contains
moisture, which it forces out. (2)1 It contains air,
which the darkness of its wintry cold condenses so
as to form moisture. (3)1 By nature, too, it has
itself the power of changing into moisture : this
power it habitually exerts.

XI

You have still a difficulty, you say. If the causes i
giving rise to rivers and fountains are constant, why
are their waters sometimes dried up ? and why do
they sometimes appear in places where they did not
exist before ? Their routes, I should reply, are often
disturbed by earthquakes ; the channel is cut off by a

1 The numerals here have no counterpart in the original.

122 PHYSICAL SCIENCE BK. in

fall of rock or earth, and the water being held back
seeks a fresh exit, which it forces with a certain
measure of violence ; or merely by the earth's vibra-
tion the course is shifted from one place to another.
On the surface of the earth one may observe that
rivers that have lost their channels are first of all
dammed back, but afterwards, in lieu of the course

2 they have lost, force a new one. Theophrastus
affirms that an incident of the kind took place in the
Corycian Mount,1 where, after a slight shock of earth-
quake, a fountain burst out from a fresh source.

But some writers are of opinion that other causes
too are at work to call up water in other ways, or
to drive or turn it from its course. Mount Haemus
was once destitute of water ; but after a tribe of
the Gauls, being hard pressed by Cassander, took
refuge there, and felled the woods, an immense
supply of water appeared. No doubt the woods
had attracted it for their nourishment previously.
When they were uprooted, the moisture, ceasing to

3 be used up by their roots, overflowed. Theo-
phrastus affirms that the same thing happened near
Magnesia.

But with all respect to Theophrastus, this is not
a very likely story. Everything that is most shady
tends most to gather water. But that would not be
the case if trees drained off water. Roots draw their
nourishment from their immediate vicinity ; but the
volume of river water flows from recesses far down,
and is derived from a source deeper than roots can
penetrate. Besides, when trees are cut down, more
moisture than before is required ; the stumps suck
up a supply, not merely for life, but for new growth.

4 Theophrastus tells us, too, that round Arcadia,

1 In Cilicia.

xi EFFECT OF TREE FELLING 123

which was a city in the island of Crete, the wells
and lakes disappeared, because the land ceased to
be tilled after the destruction of the city ; but after
it had got back its tillers, it recovered its waters
also. He sets down as the cause of the dry ness,
that the earth had got hidebound and quite hard,
and not being stirred could not transmit to the
underground reservoirs the rain that fell. But if
this is true, how comes it that we see springs in
great plenty in the most desert ground? In fact, 5
one finds a great deal more ground that began to
be tilled on account of the abundance of water than
that began to have an abundant supply of water
because it was tilled. You may be quite sure that
it is not mere rain water that is carried down in our
greatest rivers, navigable by large vessels from their
very source,1 as is proved by the fact that the flow
from the fountain-head is uniform winter and summer.
Rainfall may cause a torrent, but it cannot maintain
the steady, constant flow of a full river. Rains cannot
produce, they can only enlarge and quicken, a river.

XII

LET us, if you please, go into the matter a little
more deeply, and you will soon see that you have
no cause to put further questions, once you reach
the true origin of rivers. A river is, of course,
formed by a supply of water that is always constant.
If you ask me, therefore, how water is produced, I
will ask in my turn how air or earth is produced.
If there are four elements in nature, you are not
entitled to ask where water, one of them, comes

1 The text seems to be at fault, but the argument is quite clear.

i24 PHYSICAL SCIENCE BK. HI

2 from ; it is the fourth part of nature. Why, there-
fore, are you surprised that so great a portion of
nature can furnish a perpetual supply of liquid from
itself? Just as the atmosphere, which is likewise a
fourth part of the universe, is the source of winds
and breezes, so is water, of streams and rivers. If
wind is atmosphere in motion, so is a river water in
motion. I have given it strength enough in saying
that it is one of the four elements. You must be
aware that what has an element as its source can
never run short.

XIII

1 WATER is, according to Thales, the most powerful
of the elements. He thinks it was the first of them,
and that all the others sprang from it. We Stoics,
too, are also of the same opinion ; or perhaps I
should rather say that we think it is the last.1 For
we say that it is fire that lays hold upon the world
and changes all things into its own nature. We
suppose that fire eventually fades and sinks, and
that, when the fire is quenched, nothing is left in
nature save moisture, in which lies the hope of the
world that is to come. So fire is the end, moisture
the beginning, of the world. Can you wonder that
rivers may always issue from this, which was before
all things, and from which all things have been

2 formed? In the separation of the elements [at
the beginning] the moisture was reduced to a
fourth part, and was placed in such a situation that
it could furnish a sufficient supply for rivers,
streams, and fountains. The next opinion expressed

1 I.e. that to which all others may be reduced : the text seems corrupt,
and the meaning is more or less conjectural. Gercke's text reads, "are also
of the same or an analogous opinion."

xin THALES* MISTAKES 125

by Thales is a silly one. The whole earth, he says,
is upborne by water, and floats just like a boat ;
when it is spoken of as trembling, it is rolling by
the movement of the water. It is no wonder, then,
that there should be abundance of water to pour
forth in rivers, since the world is itself wholly set
in water. You should put out of court such an
antiquated, unscientific idea. There is no ground
for believing that the water comes in through the
chinks in the earth's sides, and forms bilge-water
in her centre.

XIV

THE Egyptians have recognised four elements also ;
and they then form each into two, male and female.
The atmosphere they consider male where it is
windy, female where it is cloudy and sluggish.
They call the sea manly water, every other kind of
water they call womanly. Fire they call masculine
where a flame is burning, and feminine where there
is a glow that is harmless to touch. The firmer
kinds of earth, such as boulders and crags, they call
male, reserving the term female for the parts that
are amenable to cultivation.

XV

THERE is but one sea, which has so existed no doubt
from the beginning of things. It has sources of its
own, from which its impulses and tides are derived.
As with the raging sea, so with this gentler kind of
water, there is a vast supply1 in secret, which no

1 All the texts give via = -way. The obvious correction is vts = amount,
supply. Gercke confirms this correction.

126 PHYSICAL SCIENCE BK. m

river course can drain dry. The exact explanation
of its reserve strength has not yet been discovered.
It is only the superfluous portion of it that is

2 released. Now, there are some of these beliefs
to which we may safely subscribe ; but I hold this
further opinion. My firm conviction is that the
earth is organised by nature much after the plan of
our bodies, in which there are both veins and arteries,

3 the former blood-vessels, the latter air-vessels. In
the earth likewise there are some routes by which
water passes, and some by which air. So exactly
alike is the resemblance to our bodies in nature's
formation of the earth, that our ancestors have
spoken of veins ( = springs) of water. Again, in
our bodies there is not merely blood, but many
other kinds of moisture, some essential to life,
others tainted and somewhat thick — brain in the
head, marrow in the bones, mucus, saliva, tears,
and a kind of lubricating substance that suffuses the
joints, and enables them to turn more quickly
( = synovial fluid).

So, too, in the earth there are several different

4 kinds of moisture. There are some kinds that
grow hard when fully formed. Hence arises all the
metalliferous soil, from which our avarice seeks
gold and silver. Then there is the kind which
turns from liquid into stone. In some localities
the earth and its moisture combine to form a
liquid like bitumen and other substances of the
same kind. There, then, we find the cause of
waters produced according to the law and will

5 of nature. But as in our bodies, so in the earth,
humours often contract taints of various kinds. A
blow, or some shock, or exhaustion of the ground,
or cold or heat injures the natural vigour. A vein

xv ANALOG Y FROM HUMAN BOD Y 127

of sulphur, too, may solidify the moisture, lasting
for a longer or shorter time. Therefore, as in our
bodies, when a vein is cut, the flow of blood lasts
till the blood is exhausted or the incision in the
vein has closed up and stopped it, or until some
other cause has staunched the blood ; in like manner
in the ground, when the seams have been loosened
and laid bare, a stream or river rushes forth. The 6
way in which the water is used up depends on the
extent of the opening in the seam. At one point
its flow is checked by some obstacle ; at another it
heals up, so to speak, into a scar and chokes the
path it had made ; at another the power of trans-
mutation, which we have said the earth possesses,
reaches its limit and cannot longer supply material
that may be liquefied : sometimes the exhausted
source is replenished, now by energy self-recruited,
now by a supply drawn from external sources. For I
ought to say that often dry objects placed opposite
to wet attract the moisture to them. Earth itself, 7
which easily assumes another form, often wastes
away, and is dissolved in moisture. The same
phenomenon occurs under the earth as above it in
the clouds ; becoming too dense and heavy to retain
longer its own character, solid begets liquid. There
is often a gathering of thin, scattered moisture like
dew, which from many points flows into one spot.
The dowsers call if sweat, because a kind of drop
is either squeezed out by the pressure of the ground
or raised by the heat. This slender trickle scarce
suffices to form a spring. But if the sources are
great and the gatherings great, rivers issue. Some-
times they flow gently if the water merely descends
by its own weight, sometimes with violence and
loud roar if air be intermingled and eject the water.

128 PHYSICAL SCIENCE BK. in

XVI

1 ANOTHER peculiarity requires explanation : some
wells are full for six hours and dry for six alter-
nately: why is this so? It is hardly necessary to
name the rivers individually which are at certain
months broad, at certain narrow, and to give
separate causes of this, seeing I can give a common
explanation that applies to all. An ague returns
at the same hour, gout always keeps its appointment,
the custom of women, unless interrupted, observes
its stated period, birth is ready at the proper month.
In like manner waters have their intervals of recur-
rence, at which to withdraw and at which to return.

2 Now, some intervals are shorter, and the more strik-
ing on that account ; some are longer, but no less
certain. And what is strange in that, when you see
that the succession of events, and all nature, by decree
preserve their appointed order ? Winter has never
mistaken its time. Summer has always blazed forth
in its season. The changes of spring and autumn
have occurred according to their wont. Solstice and
equinox alike have kept their appointed days.

Beneath the earth likewise there are laws of
nature, less familiar to us, but no less fixed. Be
assured that there exists below everything that you
see above. There, too, there are antres vast, im-
mense recesses, and vacant spaces, with mountains

3 overhanging on either hand. There are yawning
gulfs stretching down into the abyss, which have
often swallowed up cities that have fallen into them,
and have buried in their depths their mighty ruins.
These retreats are filled with air, for nowhere is
there a vacuum in nature ; through their ample

xvi DENIZENS OF UNDERGROUND WATER 129

spaces stretch marshes over which darkness ever
broods. Animals also are produced in them, but
they are slow -paced and shapeless ; the air that
conceived them is dark and clammy, the waters are
torpid through inaction. Most of these creatures
are blind, such as moles and underground rats,
which have no sense of sight, since it is unnecessary
for them. From these depths fish are, according
to Theophrastus, dug up in certain localities.

XVII

AT this point many pleasantries will occur to you i
to apply to my incredible narrative, which you will
politely call a good story. A man will no longer
go to fish with net and hook, but with his mattock !
The next thing will be for some one to go out
hunting at sea. Now what reason is there, I ask,
why fish should not cross the land if we can
cross the sea and change our abodes ? You are
surprised at this happening. How much more
incredible are the achievements of luxury as often
as it either counterfeits or vanquishes nature ? Fish
are to be found swimming in the dining couch ; one
is caught right under the table, to be transferred
immediately to the table. A mullet is not thought 2
fresh enough unless 'it expires in the hand of the
banqueter. These fish are handed round enclosed
in glass jars, and their colours are observed while
they expire ; death paints many hues on them as
they draw their last struggling breath. Others are
pickled alive and killed in the sauce. These are
the people who think one is romancing who asserts
that a fish can live underground and instead of

K

1 30 PHYSICAL SCIENCE BK. in

being caught can be dug up ! How inconceivable
it would sound to them to hear that a fish swam
in sauce and was killed during dinner, but not to
be served at dinner ; that first it was long admired,
and that the eyes were feasted on it before the
gullet was !

XVIII

1 SUFFER me here to lay aside my subject, and to
apply the scourge to luxury ! Commend me for
a beautiful sight, says one, to an expiring mullet.
In the death-struggle, as its life ebbs away, first a
ruddy glow, then a pallor suffuses it. How sym-
metrical are the variations as it changes from tint to
tint between life and death ! Our somnolent, jaded
luxury gets a long respite by means of this.1 It was
late in waking up to find how cruelly it had been
circumscribed in being cheated of such a pleasure !

2 Hitherto only fishermen have been able to enjoy this
grand and beauteous sight. But why should we at
the banquet be satisfied with a cooked, a lifeless fish ?
Let him expire on the very tray. We used to be
surprised at the fastidiousness of our epicures in
refusing to touch fish unless it had been caught on
the same day, when, as the saying goes, it smacked
of the briny. It used for that reason to be delivered
post haste — way had to be made for the breathless

3 porters as they hurried along shouting. To what
lengths have refinements now been pushed ? A fish
killed to-day has come to be considered as already

1 The passage is almost hopelessly corrupt. The meaning of this sentence
seems to be that luxury gets some respite from the fatigues of the table by
watching the mullet's death-struggle. Ruhkopf suggests an emendation which
would give the sense : Our somnolent, jaded luxury has taken a long time to
discover this new enjoyment. That would certainly be well in keeping with
the following sentence.

xviii FASTIDIO US L UXUR Y 131

stinking. " He was taken out of the water this day,
I assure you." " I cannot trust you in a matter of
such moment. I must have the evidence of my
own senses ; let the creature be brought here and
breathe out his life before my eyes." Such a pitch
of fastidiousness has the gourmands' palate reached
that they will not taste a fish unless they have seen
it swimming and throbbing in the very banqueting
room.

The more skill our jaded luxury has had placed 4
at its disposal, the more refined and elegant the
devices that in its frenzy it day by day invents ; it
spurns everything that is common. We used to
hear the remark, " Nothing can surpass a mullet
caught on the rocks " ; but now it runs, " Nothing
equals the beauty of an expiring mullet. Let me
hold in my own hands the glass vase, to see him
jump and quiver." After long and fulsome praise 5
has been lavished on him, he is taken out of his
transparent pond. Then each guest shows off his
experience of such scenes by pointing out the hues
to his fellows. " Look how the red bursts forth,
deeper than any carmine ; look at the veins he has
along his sides : see, you would think his belly was
covered with blood ; what a gleam of dark blue shot
forth just under the brow ! Now he is stretching
himself out, and sinking to a uniform pallid hue ! "
Not one of these selfish fellows would sit by a dying
friend's bedside, none of them can endure the sight
of a father's death — a sight they have dearly longed
for. How few will attend the funeral of a relative ! 6
The last hour of brothers and friends is shunned by
them ; they are all in a hurry to be in at the death
of a mullet ! For he has a delicate beauty, don't
you know, that nothing can surpass. My impatience

132 PHYSICAL SCIENCE BK. in

makes me sometimes exceed the bounds of decency
and use words at random. These drivellers are
not satisfied to bring teeth, and palate, and stomach
to the revel ; they make their very eyes partners
in the gluttony.

XIX

1 BUT to return to my subject. Here is a proof I
have to give you that in the underground recesses
are concealed great quantities of water which
abound in filthy fish. Any time that the water
bursts out, it brings in its train a huge crowd of
creatures foul to sight, disgusting and noxious to
taste. At any rate, once, near the city of Hydissus
in Caria, a flood of underground water threw up to
the light of day a number of strange fishes, and all

2 who ate them died. And no wonder. Their bodies
were full of oil from their long inactivity ; they had
been fattened in the darkness without exercise, and
deprived of that light whence health is derived. A
further proof that fish may be produced in those
depths of earth is afforded by the breeding of eels
in shady places ; they also are a heavy diet through
their want of exercise, especially if a considerable
depth of mud has hidden them quite out of sight.

3 So then the earth contains not only veins of water
by the union of which rivers may be formed, but
also streams of very great size. In some cases their
channel is concealed throughout, until they are
swallowed up in some cavern ; others of them well
up in the bottom of some lake. Everybody knows
that some marshes have no bottom. What is the
point of my argument ? It shows plainly that
mighty rivers have here unending supplies whose

xix PROPERTIES OF WATERS 133

limits are incalculable, just as is the duration of
rivers and fountains themselves.

XX

FOR the variety of taste in water there are four i
causes. The first is the kind of soil through which
it flows. The second also depends on the soil when
the water arises from transmutation of it. The
third is from air which has been transformed into
water. The fourth comes from some taint which
water often contracts when injuriously affected by
foreign bodies. These causes impart to water, first, 2
variety of taste, then medicinal power, its heavy
pestilential smell, its lightness and heaviness, its
heat and its excessive astringency. It is affected by
its passage through ground full of sulphur, or nitre
( = saltpetre), or bitumen. If the water is tainted in
this way, the drinking of it endangers life. This is
the explanation of a passage in Ovid :

The Ciconians have a river a draught of whose waters turns into

stone
The bowels ; which mantles in marble all that it touches.

The river in question has medicinal properties, its 3
mud being of the kind that glues together and
hardens the bodies it encounters. Just as the dust
at Puteoli becomes stone if it touches water, so,
contrariwise, if the water of this river touches a
solid body, it adheres and gets firmly affixed to it.
This is the reason why objects thrown into the
same lake1 are constantly found to be turned to
stone when they are taken out. This occurs at
several places in Italy ; you may put into the water

1 The allusion is not quite evident.

i34 PHYSICAL SCIENCE BK. m

a twig or bough and a few days after you can

4 take out a stone. The mud surrounds the object
and gradually coats it over. This will seem the
less surprising if you have remarked that the Albula,
and, generally speaking, all water charged with
sulphur, deposit a coating of it on the banks of their
channels and streams. Some one or other of the
foregoing causes accounts for the peculiarities of
those lakes, whereof who tastes with the lips, in the
words of the same poet,

Goes raving mad or endures a sleep of wondrous depth.

5 The effect is like that of strong drink, only more
violent. Drunkenness is madness until its effects pass
off; with a weight like lead it bears down its victim
into sleep. In the like manner the strong infusion
of sulphur in this water contains a sort of poison
that is more potent owing to the noxious atmosphere,
and either goads the mind to madness or weighs
it down in deep sleep. The river in. Lyncestis
likewise possesses this baleful power :

For whoso with intemperate lips has drained a draught,
Staggers as if having drunk deep of wine undiluted.

XXI

THERE are certain caves a glance down into which
has cost people their life. So swift is their destruc-
tive power that it kills in flight the birds that cross
them. That is the kind of air and the kind of
place from which waters of death escape. If the
infection of the air and place is less severe, the
damage is less fatal too, merely affecting the sinews
like men overpowered by intoxication. I am not

xxi SOMNOLENCE— INTOXICATION— POISON 135

at all surprised that place and air infect water and
render it similar in character to the tract through
which and from which it proceeds. Similarly, milk
shows the taste of the cow's fodder, the quality
of the wine comes out even in the vinegar it yields.
There is, in fact, nothing that does not bear marks
of its origin in the same way.

XXII

THERE is another species of water which we Stoics
are satisfied must be coeval with the world. If the
latter has existed from all eternity, so must it too.
If the world has had some beginning, then the
water was assigned its place at the creation. You
want to know what kind of water I mean ? I mean
the Ocean and all its seas that wash the continents
of the earth. Some philosophers are convinced
that the rivers likewise whose nature is inexplicable,
date from the creation of the world ; such are the
mighty rivers Danube and Nile, too remarkable to
be supposed by any possibility to have the same
origin as other rivers.

XXIII

SUCH is the division of various kinds of water,
as it presents itself to some minds. After that come
waters of the sky, which the clouds pour down from
the upper regions. Of terrestrial waters, they say,
there are some that overflow, so to speak, and
creep along the surface ; others are concealed under-
ground. I have already explained all these.

136 PHYSICAL SCIENCE

XXIV

SEVERAL explanations are given of the temperature
of water. Sometimes it is hot, sometimes it boils
so fiercely that it cannot be used until it has given
off its steam in the open, or is tempered by
mixing cold water with it. Empedocles is of
opinion that as there are fires concealed in many
places beneath the earth, water is heated when they
happen to lie beneath the ground through which it
has to flow. Let me use an illustration. We are in
the habit of constructing serpentines,1 and cylinders,
and vessels of several other designs in which thin
copper pipes are laid in descending spiral coils. The
object is to make the water meet the same fire over
and over again, and flow through a space sufficient for
heating it up ; so, entering as cold it comes out hot.
Empedocles supposes something of the same kind
to take place underground. People who have their
baths heated without fire may well believe that he
is right. In this case air from the heated furnace
is introduced. The air glides along the passages,
warming up the walls and vessels of the bathroom
just as if fire had been directly applied. In short,
all the cold water in these instances is changed into
hot by merely passing through a heated medium ;
and inasmuch as it is conveyed in an enclosure
there is no evaporation to impart a flavour to it.2
Others, again, suppose that the water contracts heat
by issuing from or passing through ground charged
with sulphur ; the heat is imparted by the properties

1 The technical name is "worm."
2 There is considerable doubt regarding the correct text and meaning.

xxiv TEMPERATURE OF WATER 137

of the material, to which also smell and taste bear
witness. All substances, I may say in general terms,
tend to reproduce the qualities of the medium by
which they have been warmed. If you are surprised
at sulphur warming water, you have only to pour
water over quicklime ; it will at once evolve heat.

XXV

SOME waters are fatal, although they give no in- i
dication of this either by smell or taste. In
Arcadia, near Nonacris, the river called by the
people there the Styx lures strangers to ruin, as
its appearance and smell rouse no suspicion. This
is like the drugs of accomplished poisoners, which
cannot be detected save by their fatal effects. The
water I mentioned a little above brings destruction
with amazing swiftness, and allows no opportunity
of applying a remedy. It hardens immediately it is 2
drunk, and, much like chalk under the influence of
water, it sets and binds fast the bowels. There is
a poisonous water in Thessaly, near Tempe, shunned
by all cattle and wild beasts. It comes out through
seams of iron and copper, and contains the power
of softening the very hardest material. It does
not nourish any trees either, and it kills grass.
Certain rivers possess a peculiar and strange
power. Some there are whose draught dyes whole
flocks of sheep. Within a short time those that
were black have white fleeces ; in other cases those
that came white go away black. This is what two
rivers in Boeotia do, one of which from its effect is
called Melas (Blackwater). Both the rivers issue
from the same lake, to go on their opposite

138 PHYSICAL SCIENCE BK. in

3 missions. So, too, in Macedonia, Theophrastus
asserts there is a river to which shepherds who
desire to turn their sheep white bring them. If
the sheep drink it for any length of time, their
colour changes as if they had been dyed. But if
those people want a dark wool, they have a dyer
ready at hand who charges nothing ; they have
merely to drive the same flock to the river Peneus.
I have recent authorities for the statement that
there is a river in Galatia that has the same
power of changing the colour in all animals,
while in Cappadocia there is one which if drunk
changes the colour of horses but not of any
other animal ; their skin is dappled with white
spots.

4 It is well known that there are lakes whose
waters bear up those who cannot swim. There
used to be a pool in Sicily, there still is one
in Syria, in which brickbats float, and no objects
thrown in, however heavy, will sink. The cause
of it is obvious. Weigh any object and com-
pare it with water while they are equal bulk for
bulk. If the water is the heavier, it will bear the
object that is lighter than itself, and will raise it
above its surface to a height proportionate to its
lightness ; objects heavier than the water will sink

5 in it. But if the weight of water and of the object
compared with it in respect of weight be equal,
the object will neither go to the bottom nor yet
will it stick up ; it will just be in equipoise with the
water. It will float, it is true, but almost submerged
and without any part projecting. The differences
in weight give the reason why some logs float
almost entirely above water, while some sink to
their centre, and some go down until they are in

xxv SPECIFIC GRAVITY 139

equipoise with the water. For it always holds good
that, when the weights of the two are equal, neither
yields to the other ; but objects heavier than water
sink, those lighter are upborne.

Now heavy and light do not refer to our judg- 6
ment of weight, but are relative to the medium
by which an object is to be supported. So when
water is heavier than the human body or than a
stone, it does not allow the inferior weight to sink.
So it comes to pass that in some lakes even stones
will not go to the bottom ; I mean hard solid
stones. There are many light pumice stones,
of which in Lydia whole islands that float are
composed. Theophrastus is my authority for
the statement. I have myself seen a floating
island in the lake near Cutiliae. Another is
carried about in the Vadimonian Lake, another
in the lake by Statonia. The island at Cutiliae 7
contains trees and grows grass, and yet it is
borne up by the water, and is wafted now in this
direction, now in that, not merely by wind, but
even by a mere air. So light the breath that moves
it that night and day it never remains stationary
in one spot. There are two reasons for it : first,
there is the weight of the water, which is medicated
and therefore heavy ; and then there is the portable
material of the island itself, which contains no solid
body, although it supports trees. Perhaps in the first 8
instance the thick liquid laid hold upon and made
fast light trunks and boughs scattered over the
surface of the lake. So also whatever rocks are
in the island, you will find porous and hollow. They
resemble those formed of moisture that has hardened
especially near the banks of medicinal springs ; in
such cases the scourings of the spring coalesce and

1 40 PHYSICAL SCIENCE BK. in

the foam is solidified. It is necessarily light, being
formed by concretions of windy, empty material.

9 There are other peculiarities attaching to waters
of different kinds, of which no explanation can be
offered. For example, why should Nile water make
women more fruitful ? So effective is it in this
respect that in some instances wombs shut up in
prolonged barrenness have relaxed so as to render
conception possible. Or why should certain waters
in Lycia prevent miscarriage, being sought after by
ladies who are subject to this frailty ? For my own
part I set these down among vulgar errors. It is
firmly believed by people that certain waters, whether
applied outwardly or taken inwardly, affect the body
with scab, certain with leprosy and foul blotches
over the skin. Water gathered from dew, they say,

10 has this fault. Wouldn't any one suppose that water
that turns into ice is the heaviest of all ? The
truth is just the opposite of this. The change takes
place in the thinnest water, which for that very
reason is most easily congealed by the cold. The
origin of the stone that resembles ice is plain from
the very name used for it by the Greeks. They apply
the term crystal (Kpv<rra\\o<;) equally to the transparent
stone and to the ice from which the stone is supposed
to be formed. Rain water, which contains very little
solid matter, once it is frozen becomes more and
more condensed through the persistence of the longer
cold until all the air is expelled, and it is compressed
to the last degree ; then what was once moisture is
changed into stone.

RISE OF RIVERS IN SUMMER 141

XXVI

SOME rivers rise in summer like the Nile, of which i
I will give an account later on. Theophrastus
makes himself responsible for the statement that
in Pontus likewise certain rivers rise in the summer
season. Four different causes are assigned for this.
First, the earth is at that period most readily
changed into moisture. Second, there are in the
remote districts heavier rains, the water from which,
rinding its way by secret channels, comes unnoticed
to swell the volume of the rivers. A third ex-
planation is that the estuary is exposed to more
frequent winds, and is lashed by the sea waves ; the
river is checked and seems to increase because it
cannot discharge freely. The fourth reason connects 2
itself with the heavenly bodies. These bodies by
their more severe pressure during certain months
drain the rivers ; when they retire to a greater
distance, the waste and drain are less. What was
previously lost now accrues by way of increase.
Certain rivers fall visibly into some grotto or other,
and thus are withdrawn from sight; some are
gradually wasted and disappear. They return,
however, at some distance off and recover their
name and course. The reason is plain enough. 3
There is vacant space underground. All liquid
naturally is carried to the lower level and to the
unoccupied space. The rivers received into these
recesses have run their course there in secret. But
as soon as any solid obstacle blocks the way, they
burst through the part that offers the slightest
obstruction to their escape and regain their channel
above ground.

i42 PHYSICAL SCIENCE BK. in

So when Lycus has been swallowed up by the yawning earth,
He comes forth far thence, and is born from another source.
So is now drunk up, now gliding with silent stream,
Is restored to its Argolic waves the mighty Erasmus.

4 In the East as well as the West this happens. The
Tigris is absorbed by the earth and after long
absence reappears at a point far removed, but un-
doubtedly the same river. Some fountains cast
out their scourings at a fixed period ; the fountain
Arethuse does so every fifth summer during the
Olympic festival. Thence comes the belief that
the Alpheus makes its way right from Achaia
to Sicily, stealing under sea by secret sluice, and
reappearing only when it reaches the coast at
Syracuse. On that account, during the days on
which the Olympic festival is taking place, the dung
of the victims offered in sacrifice being thrown into
the stream of the river (Alpheus) turns up in

5 quantity away in Sicily. You have yourself told
the story, my dear Lucilius, in your own poem, and
so has Virgil, who says in his address to Arethuse :

So when thou glid'st beneath Sicilian seas,

Never may sea nymph mingle bitter salt waves with thine.

In the Carian Chersonese there is a fountain of
the Rhodians which at long intervals sends up
from its depths certain foul excretions of mud, until

6 it is set free of them by being cleaned out. At
certain places wells throw up not merely mud but
also leaves, and bits of crockery and any other
filthy things that have accumulated in them. The
sea does the same everywhere, its nature being to
drive ashore all filthy impurities. In the neighbour-
hood of Messana and Mylae as it boils and tosses
in storms it throws up on the beach something

xxvi PURGING OF IMPURITIES 143

actually like ordure, which has a vile smell too.
Whence comes the fable that the oxen of the sun
are stalled in that neighbourhood. In certain cases
of this kind it is difficult to reach the true explana-
tion, especially when the time of the occurrence
in question has not actually been observed and is
therefore doubtful. But though the immediate and 7
special cause cannot be discovered, there is a general
one worth mentioning ; all waters when standing
and enclosed tend to throw off impurities. In water
that has a current the impurities cannot settle, as
they are carried down and expelled by the mere
force of the stream. The waters which do not
throw off foreign bodies that settle in them always
boil more or less. As for the sea, it drags from
its lowest depths dead bodies, refuse of vegetation,
and all kinds of wreckage, and purges itself of them,
not merely when its billows rage in a storm but
likewise in its calm and peaceful moments.

XXVII

THE occasion reminds me of a wider question, i
When the fated day of deluge comes, after what
fashion will the earth for the most part be over-
whelmed by the waves ? Will it be by the strength
of Ocean and the rise of the outer sea against us ?
Or will the rain descend uninterruptedly, and will
summer be cut out of the year while persistent
winter bursts its clouds and pours down endless
masses of water ? Or will earth herself open new 2
reservoirs and shed forth rivers more abundantly ?
Or will a single cause be insufficient to produce
such a catastrophe, and all the methods conspire

144 PHYSICAL SCIENCE BK. in

together, the rains descending and the river floods
rising, and the seas hurrying in hot haste from their
place — all agencies in concert bent upon the one
aim, the destruction of the human race ? The last
is the truth. Nature finds no difficulties in com-
passing her ends, especially when she hastens to
make an end of herself. At the creation of things
she economises her efforts, putting forth her energy
in small imperceptible increase : for destruction she

3 comes with sudden and irresistible might. How
long a time is needed to bring the embryo child
to the birth! How great the toil called for in
rearing the tender infant ! How careful the nurture
through which the frail body is at length brought
to manhood ! But how insignificant the effort
needed to undo it all ! Cities take centuries to
establish : an hour brings their ruin. Ages rear
the forest : a moment turns it to ashes. To
its stability and vigour this universe of things
calls for great and constant protection ; quickly and

4 suddenly dissolution comes. Deviation by nature
from her established order in the world suffices for
the destruction of the race.

So when that day of fate comes, many causes will
be at work in fulfilling its decrees ; and as some, in-
cluding Fabianus, think, such a change will not come
without a shock to the whole universe. In the first
instance there will be excessive rainfall, a dull leaden
sky with never a glimpse of the sun. The clouds
will be unbroken, the gathering moisture will cause
thick darkness, and there will be no winds to lick

5 it up. Hence the crops will be diseased, the grain
ere it be grown will wither without fruit. All tillage
of man's hand will be ruined ; marsh grass will
spring up over all the plains. Presently the stronger

THE DELUGE 145

plants feel the strain ; their roots are loosened, and
the pollard elms fall forward, carrying their vines
with them. All shrubs lose their hold on the soil,
which has become soft and flabby. Soon the ground
is so saturated that it can support neither grain nor
fruitful pasture. The stress of famine is felt, and
recourse is had to the ancient sustenance of berries.
The fruit is shaken from ilex and oak, and any
other tree that has been able to keep its ground by
the support of the clefts of the rocks in the moun-
tains. Roofs are sodden and rickety ; the rain has 6
penetrated to the depths, and the foundations sink.
The ground is all a marsh. It is vain to seek
supports to the tottering houses ; every foundation
is set on slippery ground, and in the muddy soil
nothing is firm. After the storm-clouds have more
and more densely massed, and the accumulated
snows of centuries have melted, a cataract sweeps
down from the lofty mountains carrying before it
the woods now insecure in their place, tearing off
boulders from their fastenings, and whirling them
down in fierce career. It washes off the country ^
houses, and takes down with it flocks of sheep
among the debris. The smaller hamlets it carries
off as it passes, but at length it leaves its course
and rushes in fury upon the larger homesteads.
It draws in its career whole cities, inhabitants, and
buildings all mixed together : people know not
whether to complain of a catastrophe or a shipwreck.
So utterly crushed are they and at the same time
submerged by its coming.

By and by, as it advances, the cataract is
swollen by the absorption of other torrents, and in
devastating course roams through the whole plain.
Finally, it holds universal sway; it has earned a

146 PHYSICAL SCIENCE BK. in

title by the widespread destruction of the world

8 which it carries as its burthen. The rivers, too,
originally large, have been so hurried down by the
storms that they have left their channels. The
Rhone, the Rhine, the Danube, even when confined
within their banks, have an impetuous torrent.
What, suppose you, are they now that they have
overflowed and made themselves new banks, and,
cutting through the soil have all wandered from
their wonted course ? With what headlong rush
they roll down ! The Rhine overspreads the plains,
but the wideness of the space causes no slackening
of its energy ; it pours its waters in full force over
the whole extent as if it were rushing through a

9 gorge. The Danube no longer washes the base, or
even the middle, of the mountains ; it lashes the
very summits, bearing down with it the mountain
sides it has flooded, the crags it has overturned,
the beetling promontories through whole provinces ;
it undermines their foundations, and carries them far
off from the mainland. And, after all, the river finds
no exit — for it had closed up every passage against
itself — but returns in a circuit, and envelops in one
vast whirlpool the huge expanse of lands and cities.

Meantime the rains continue, the sky becomes
still more threatening, and thus, for long, disaster
is heaped upon disaster. What was once cloud

10 is now profound night, and that, too, dread and
terrible, with gleams of lurid light between. For
frequent flashes show, and squalls disturb the sea.
Then for the first time, feeling the increase from
the rivers, and too narrow to contain itself, the
main advances its shores. Its own bounds cannot
contain it, and yet the torrents from land prevent
its escape, and drive back its waves. Still, the

xxvn WATER, WATER EVERYWHERE 147

greater part of the torrents detained by their
narrow mouth recoil in pools, reducing the fields to
the aspect of a continuous lake. Now everything,
far as the eye can reach, is a waste of waters.
Every hill is hidden in the abyss, everywhere is u
fathomless depth of water. Only in the highest
mountain tops are there shallows. To these
heights men have fled with wives and children,
and have driven up their cattle. All intercourse
and communication have been cut off among the
wretched survivors; for all the lower ground has
been filled by the waves. The remnants of the
human race cling to every lofty peak. Brought
to the last shift, they have this one solace, that
apprehension has passed into stupor. Astonishment
so fills them that there is no room for fear. Even 12
grief finds no place ; for it loses its force in one
whose wretchedness has passed beyond perception
of suffering. So there are only mountain tops that
appear like islands above the water, and increase the
number of the scattered Cyclades, as that accom-
plished poet finely says ; with an exaltation of lan-
guage too in keeping with his theme, he exclaims :
All was sea ; to the sea there was no shore.

It is a pity he reduced that burst of genius and his
splendid subject to childish twaddle by adding :

The wolf has to swim among the sheep, the wave carries tawny
lions.

There is too little seriousness in making sport in 13
this way when the earth has been swallowed up.
He expressed a fine thought and caught a vivid
picture of the utter confusion when he said :

Through the open plains the rivers wander at their will,
. The towers totter and sink beneath the flood.

i48 PHYSICAL SCIENCE BK. in

That was splendid, if he had not minded what the
wolf and the sheep were doing. Could anything,
in fact, swim amid such deluge and destruction ?
Was not every hoof drowned in the same torrent
as carried it off? You conceived a worthy image,
Ovid, when all the world was overwhelmed, and the
sky itself descended upon earth. Keep it up. You
will know what it ought to be if you reflect that the
whole world was afloat. Now we must return to
our discussion.

XXVIII

1 THERE is a section of philosophers who hold that
while the earth may be greatly harassed by exces-
sive rains, it cannot be overwhelmed by them. By
a mighty blow this mighty earth must be smitten.
Rain will spoil the crops, hail will knock off the
fruit ; but the rivers will only be swollen above their
banks, and will subside again. Some, again, are
satisfied that the cause of the widespread destruction
will be derived from the movements of the sea.
The great shipwreck of the world cannot, they
think, arise from injury by cataract, river, or rain.

2 I am willing to grant that when that day of
destruction is at hand, and Heaven is resolved to
create a new race of men, the rain will pour down
incessantly, and there will be no limit to the floods,
the north and other dry winds will cease to blow ;
the south will bring up in plenty clouds and rain
and stream.

But hitherto only damage has been inflicted.
The crops are laid low, and to the grief of the farmer,
All hope of increase is abandoned ; the toil of the long year is
wasted and vain.

xxvin RAIN— RIVER— SEA

149

But for our purpose the earth must be more
than damaged, it must be submerged. In fact, the
disasters described are merely the prelude to
destruction. After that, the seas swell far beyond
their wonted bounds, sending out their waves far
above the farthest high-water mark of the most vio-
lent tempest. The winds will urge them on from the 3
rear, rolling up huge billows that will break far inland
out of sight of the highest shore. In course of time
the shore will thus be shifted forward, the deep will
be established in a realm that is not its own ; the
mischief will come nearer, and from its new base
the tide will issue still from the deepest recesses
of the main. For just like atmosphere and ether,
this element, sea, has a large reserve, and in
its depth is far more copious than appears to the
eye. This reserve, moved by fate, not merely by
tides — for tides are but the agency of fate — raises
and drives before it a gulf of vast extent. Then in 4
wondrous wise it rears its crest, and overtops all man's
refuges of safety. Nor do the waters find this a
hard task, since, if the heights were calculated, it
would be found that the sea mounts from an eleva-
tion equal to that of earth. The surface of the sea
is of uniform level ; for the earth itself as a whole is
uniformly level. Hollows and plains are everywhere
below the general level.

But the whole globe is as a matter of fact formed
into a regular sphere, while in part of it is the sea,
which unites to form the unity of a single ball. But
just as when one looks out across a plain, the 5
ground that sinks gradually deceives the eye, so
we are not aware of the sea's curvatures, and all
that is visible is a plain. But being on a level with
the earth, the sea does not require to raise itself to

150 PHYSICAL SCIENCE BK. in

any great height in order to overflow. In order to
overtop what is on a level with it, it need make only
a slight rise. Besides, the flow of it does not pro-
ceed from the shore where it is lower, but from mid
ocean where the heap in question stands. Therefore,

6 as the tide at the equinox soon after the conjunction
of moon and sun rises to a height greater than at
any other time of year ; in like manner this one
that is sent out to seize upon the earth must exceed
in violence the highest of ordinary tides, and bear
a far greater volume of water ; nor does it begin
to ebb until it has swollen above the peaks of the
mountains that are its objective. Some localities
have at present a tide that runs up inland for a
hundred miles in ordinary course harmlessly. It
flows up to its normal limit and then ebbs again.

7 But when the time of deluge comes, the tide,
freed from all restraint, will set no limit to its
advance. In what way ? you say. Just in the
same way as the great conflagration is destined
to take place. Both will take place when God
has seen fit to end the old order, and bring in a
better. Fire and water are lords of the earth.
From these it took its rise, and in these it will
find its grave. So when a new creation of the
world has been resolved upon by Heaven, the sea
will be let loose on us from above ; or it may be
the raging fire, if another variety of destruction
is Heaven's will.

XXIX

i SOME suppose that in the final catastrophe the earth,
too, will be shaken, and through clefts in the ground
will uncover sources of fresh rivers which will flow

SEEDS OF DESTRUCTION

forth from their full source in larger volume. Berosus,
the translator of [the records of] Belus, affirms that
the whole issue is brought about by the course of
the planets. So positive is he on the point that he
assigns a definite date both for the conflagration
and the deluge. All that the earth inherits will, he
assures us, be consigned to flame when the planets,
which now move in different orbits, all assemble
in Cancer, so arranged in one row that a straight
line may pass through their spheres. When the
same gathering takes place in Capricorn, then we
are in danger of the deluge. Midsummer is at
present brought round by the former, midwinter by
the latter. They are zodiacal signs of great power 2
seeing that they are- the determining influences in
the two great changes of the year. I should myself
quite admit causes of the kind. The destruction of
the world will not be determined by a single reason.
But I should like to apply in this connection as
well, a principle which we Stoics adopt in regard to
a conflagration of the universe. Whether the world
is a soul, or a body under the government of nature,
like trees and crops, it embraces in its constitution
all that it is destined to experience actively or
passively from its beginning right on to its end ;
it resembles a human being, all whose capacities are
wrapped up in the embryo before birth. Ere the 3
child has seen the light the principle of beard and
grey hairs is innate. Albeit small and hidden, all
the features of the whole body and of every
succeeding period of life are there. In like manner
the creation of the world embraces sun and moon,
stars with their successive phases, and the birth of
all sentient life ; and no less the methods of change
in all earthly things. Among the latter is flood,

PHYSICAL SCIENCE

which comes by a law of nature just as winter and

4 summer do. So, that catastrophe will not be pro-
duced simply by rain, but rain will contribute : nor
by inroads of the sea, but these inroads will con-
tribute : nor by earthquake, but earthquake will
contribute. All elements will aid nature, that
nature's decrees may be executed. The chief cause
of its inundation will be furnished by the earth
herself, which, as has been already said, is subject
to transmutation, and may dissolve in moisture.

5 Therefore, there will one day come an end to all
human life and interests. The elements of the
earth must all be dissolved or utterly destroyed in
order that they all may be created anew in inno-
cence, and that no remnant may be left to tutor men
in vice. There will be more moisture then than
there ever was before. At present the elements
are all carefully adjusted to the parts they have
to fulfil. To destroy the equipoise in which the
balance stands, there must be some addition to one
or other of them. The addition will be to moisture.
It has, at present, power to surround, but not to
overwhelm the earth. Any addition to it must of
necessity overflow into ground that does not now
belong to it.1 So the earth as the weaker is bound
to yield to sea which has gathered unnatural strength.
So it will begin to rot, then to be loosened and con-

6 verted into moisture, and to waste away by the
continuous drain. Rivers will then issue forth
beneath mountains, shaking them to the foundations
by their fury ; then they will flow on in silence
without a breath of air. The soil will everywhere
give forth water ; the tops of mountains will pour it
out, just as disease corrupts what is sound, and an

1 The text is uncertain, but the meaning fairly obvious.

xxix THE FINAL CATASTROPHE 153

ulcer taints its whole vicinity. The nearer the
part is to the soil that is being liquefied, the more
quickly will it be washed off, dissolved, and finally
carried away. The rock will everywhere gape in
fissures, and the fresh supplies of water will leap
down into the gulfs, and unite in forming one great
sea. There will be no Adriatic any longer, no strait
in the Sicilian Sea, no Charybdis, no Scylla. All
the fabulous dangers will be swallowed up in the
new sea ; the existing Ocean which surrounds the
fringes of the earth will come into the centre.

Nor will this be all. As if this were not enough,
winter will seize upon months that are not his,
summer will be stopped, the heat of every heavenly
body that dries up earth's moisture will be quenched
and cease. All these names will be obliterated —
Caspian and Red Sea, Ambracian and Cretan Gulfs,
the Pontus and the Propontis. All distinctions will
disappear. All will be mixed up which nature
has now arranged in its several parts. Nor will walls
and battlements afford protection to any. Temples
will not save their worshippers, nor citadels their
refugees. The wave will anticipate the fugitives,
and sweep them down from their very strong-
hold. Some enemies will hasten from the west,
others from the east. A single day will see the
burial of all mankind. All that the long forbearance
of fortune has produced, all that has been reared to
eminence, all that is famous and all that is beautiful,
great thrones, great nations — all will descend into
the one abyss, will be overthrown in one hour.

154 PHYSICAL SCIENCE BK. in

XXX

1 NATURE, as I have said, finds no task hard, and
especially one resolved upon from the beginning,
to which she does not come of a sudden, but of
which long warning has been given. From the
world's first morning, when out of shapeless uni-
formity it assumed this form it wears, nature's decree
had fixed the day when all earthly things should be
overflowed. Nay, from of old the seas have prac-
tised their strength for this purpose, lest at any time
destruction as a strange work might be found diffi-
cult to compass. Do you not see how the breaker
dashes against the beach as if it wished to leave its
element ? Do you not see how the tide sometimes
crosses its bounds and instals the sea in possession

2 of the land ? Do you not see how unceasing is the
war it wages against its barriers ? But what special
apprehension need there be of the sea, the place
where you see such turmoil, and of the rivers that
burst forth in such fury ? Where has nature not
placed water ? She can attack us on all sides the
moment she chooses. I can give my own word of
honour for it that water meets us as we turn up the
soil ; every time our avarice sends us down a mine,
or any other motive induces us to sink a shaft deep
in the earth, the end of the excavation is always a
rush of water.

3 Remember, too, that there are huge lakes
hidden deep in the earth, great quantities of sea
stored up, and many rivers that glide through the
unseen depths. On all sides, therefore, will be

xxx THE DELUGE— AND AFTER

J55

causes of deluge ; for some waters flow in beneath
the earth and others flow round it. Though long
restrained they will at last prevail, and will join
stream to stream and pool to marsh. The sea will
fill up the mouth of every fountain, and will open
it out to wider extent. Just as the bowels drain 4
the body in the draught, or as the strength goes off
into perspiration, so the earth will dissolve, and
though other causes are inactive, it will find within
itself a flood in which to sink. All the great forces
will thus, I should suppose, combine. Nor will de-
struction tarry. The harmony is assailed and broken
when once the world has relaxed aught of its needed
care. At once, from all sides, open and hidden,
above and beneath, will rush the influx of waters.
There is nothing like the letting loose of the sea's 5
full force, for violence and ungovernable fury ; it
rises in rebellion and spurns every restraint. It will
make full use of its permitted liberty ; as its nature
prompts, what it rends and surrounds it will soon fill
up. Just as fire that breaks out at different points will
speedily unite the flames and make one grand blaze,
so the overflowing seas will join forces in an instant.
But the waves will not enjoy their unrestrained 6
liberty for ever. When the destruction of the human
race is consummated, and when wild beasts, whose
nature men had come to share, have been consigned
together to a like fate, the earth will once more
drink up the waters. Nature will force the sea to
stay its course, and to expend its rage within its
wonted bounds. Ocean will be banished from our
abodes into his own secret dwelling-place. The
ancient order of things will be recalled. Every 7
living creature will be created afresh. The earth
will receive a new man ignorant of sin, born under

156 PHYSICAL SCIENCE BK. in

happier stars. But they, too, will retain their inno-
cence only while they are new. Vice quickly creeps
in ; virtue is difficult to find ; she requires ruler and
guide. But vice can be acquired even without a
tutor.

BOOK IV

CONTAINING A DISCUSSION OF SNOW,
HAIL, AND RAIN [THE NILE]

PREFACE

You tell me you are delighted, Lucilius, my most i
esteemed of friends, with your peaceful government
of Sicily. You will continue to be delighted if you
are willing to observe the bounds of moderation, and
do not try to turn into an empire what is merely a
province. Nor do I doubt that this will be your
choice, knowing as I do that you are a stranger to
ambition, and a friend to a peaceful life of letters.
Let those who cannot bear their own company, long
for a crowd of affairs and of people ! You are on
the best of terms with yourself. It is little wonder 2
that few attain such a happy lot. We are always
laying commands upon ourselves to our own dis-
peace. We suffer at one moment from love of, at
another from weariness of, ourselves. Our unhappy
soul is now inflamed with pride, now inflated with
passion. Sometimes we relax it through indulgence,
sometimes we consume it with anxiety. The most
pitiable thing of all is that we are never alone
with ourselves. So, where such a crowd of vices 3
have to mess together, there must be continual
wrangling among them. Behave, therefore, my
dear Lucilius, as you are wont to behave. Separate
yourself as far as possible from the common
herd, and expose no side to the attack of flattery.
Flatterers are adepts in spreading a net for their
159

160 PHYSICAL SCIENCE BK. iv

betters. However much you are on your guard, you
will be no match for them. If you allow yourself
to be caught, you will be delivering yourself up to

4 betrayal, take my word for it. Flattery has in it
the inherent charm, that even when spurned, it is
not unpleasing : often shut out, it is at the last taken
to the bosom. Flattery accepts its rejection as a
mark of attention ; even insults cannot subdue it.

What I am going to tell you may sound incredible,

5 yet it is the simple truth. Every man is most open
to danger on the side on which he is attacked.
Perhaps, indeed, that is the very reason why he
is attacked on that side. You must, therefore, lay
your account to recognise that, do what you will,
you cannot manage to be impervious to adulation.
When you have closed every loophole, it will still
wound you through your harness. One assailant
will employ his flattery secretly and sparingly ;
another, above board, openly, with an affectation of
honest sincerity, as if it were straightforward blunt-
ness, not device. Plancus, the greatest adept in the
art before Vitellius' time, used to say that secret,
dissembled flattery was not to be employed. Ad-

6 vances, quoth he, are lost if they are not recog-
nised. The flatterer makes most headway when he
is detected ; still more, in fact, if an open rebuke
brings the blush to his cheek. You must assume
that a public character like you will encounter many
Plancuses. It is no remedy against the inveterate
plague to refuse to be praised. I never knew a man
more shrewd in every practical matter than Crispus
Passienus, and especially in diagnosing and treating
faults of character. He often used to say that we
only put-to the door against flattery, and do not shut
it, much in the same way as in the face of a mis-

PREF. INSIDIOUS FLATTERY 161

tress. If she gives it a shove, we are pleased, still
more so if she forces it open. I remember hearing 7
that distinguished man, Demetrius, remark to a
certain powerful freedman that he, too, had an easy
road to riches on the day that he made up his mind
to renounce all virtuous resolutions. Nor will I
grudge any of you, said he, the knowledge of the
art, but I will teach those who regard gain as the \
one thing needful how they may attain their object.
They need not follow the doubtful fortune of the
sea, nor the competition of buying and selling : they
need not place their faith in the fickle proceeds of
the ground, nor the still more fickle fortunes of the
exchange. I will teach them a means of making
money not merely easy, but positively so merry that
the victims whom they fleece will share the fun.
Flattery shall be the means. If you have the 8
stature of the pigmy Thracian matched against
Thracian in the arena, I will swear that you are
taller than Fidus Annaeus or Apollonius Pycta. I
will say that no fellow could be more liberal than
you, nor shall I lie, since you may be considered to
have bestowed upon all whatever you have not
robbed them of.

The fact is, my dear Junior, the more open
and shameless flattery is, and the more completely
it has brazened its own features and raised the
conscious blush in those of others, the more quickly
it storms the citadel. We have now reached such
a pitch of madness that he who uses flattery
sparingly is considered niggardly. I used to tell 9
you that my brother Gallic — a man whom even his
most ardent admirer cannot love according to the
measure of his deserts — was a stranger to other vices,
but this he positively loathed. You might assail

1 62 PHYSICAL SCIENCE BK. iv

him on every side. One began by paying homage
to his intellect, the greatest and worthiest of all,
which one had rather see consecrated to the service
of heaven than wasted in weak human effort ; he ran
away from one who talked thus. Or one began to
praise his thrift — he was so indifferent to money that
he seemed neither to possess it nor to condemn it —
he cut short the very first words of the panegyric.

10 Or, again, one would admire his bonhomie and
unaffected grace of character, which charms even
those it passes unnoticed — a service to every one he
meets, which costs the author nothing. No one in the
world, I may tell you, is such a favourite with his one
chosen friend as he is with all. At the same time
so great is his natural amiability that it is free from
all savour of artifice or pretence. No one, you would
think, can refuse credit for a goodness in which all
share. At this point, too, he successfully resisted
your blandishments, leading you to exclaim that
you had found a man absolutely impregnable to
assaults of the flattery which no one ever refuses

11 to take to his bosom. You were forced to admit
that you respected his wisdom and determination
in escaping from that unavoidable plague, all the
more that you had hoped that your insinuating
words would be received with open ears because
they were true. Yet all the more he saw that he
must resist your wiles. For when truth is attacked
by falsehood, the attack always seeks the aid of
some measure of truth. Still, I would not have
the flatterer who tried his art upon my brother
displeased with his success, as if he had acted his
part ill while the other suspected some joke or

12 trick. You had not been detected, your advances
had simply been rejected. Now do you, Lucilius,

PREF. GALLiaS INDIFFERENCE 163

adapt yourself to this model. When any flatterer
approaches you, say to him : Do you wish to
convey a complimentary message such as passes
between magistrates duly installed in office ? Do
you think that I am prepared to return the com-
pliment, and willing, therefore, to listen to your
long story ? Neither do I wish to dupe, nor can
I be duped. I should like well enough to have
the praise of people like yourself if you did not
praise the bad as well as the good.

And yet, Lucilius, why is it necessary for you to
come down to their level, and allow them to attack
you at close quarters ? Keep a long distance between
you and them. When you desire to have genuine
praise, why should you be indebted to another for
it ? Yourself commend your own efforts. Say
thus : Though my poverty prompted another kind
of career, and tempted me to devote my talents to 13
a field which promised to application a quick return,
yet I gave myself up to liberal pursuits. I turned
aside to the unremunerative domains of poetry,
and bestowed myself upon the wholesome study of
philosophy. I have showed that seeds of virtue
are planted in every breast. I have surmounted
the difficulties of birth ; measuring my powers, not
by my lot, but by my capacity, I have reached a
position on a level with the highest. My friendship
with Gaetulicus did rtot sap my allegiance to the
Emperor Caius Caligula. Messalina and Narcissus,
long enemies of the State before they became
enemies of one another, were unable to overturn 14
my resolve to be true to others whom it was a
crime to love.1 I risked my head for my loyalty.

1 The passage is evidently corrupt ; the facts with which it deals are in
part unknown.

1 64 PHYSICAL SCIENCE BK. iv

No word was wrung from me that I could not
utter with a clear conscience. All my fears were
for my friends, none for myself, except the fear of
not proving a true friend. No womanish tears
escaped me, nor did I cling as suppliant to the
hands of any ruler. I have done nothing un-
becoming a man or a good man. Rising superior

15 to dangers, ready to face all they threatened, I
thanked fortune for affording opportunity of
showing what a price I put upon honour. Such an
issue could not be lightly esteemed in my eyes.
The suspense was not of long continuance. The
weights in the scale were by no means equal
— was it better for me to perish for honour's
sake or for honour to perish for my sake ? I did
not rush headlong to self-destruction, the refuge of
despair, to rescue myself from the mad rage of
the rulers. In Caius' time I saw tortures and
fires of persecution. Under his reign I recog-
nised at one period that the lot of humanity

16 had sunk to such a depth of misery that the
loss of one's life might be ranked among the
deeds of mercy. Yet, I did not fall upon my
sword, nor leap open-mouthed into the sea : I
would not have it seem that death was the only
service I could render for honour's sake. Add,
now, that my soul has never stooped to bribes,
amid the eager race for wealth my hand has never
reached forth to receive unjust gain. Add, too,
the thriftiness of my mode of life, the restraint
of my speech, my courtesy toward inferiors, my
respect for superiors.

After these reflections, ask yourself, my friend,
whether what you have related of yourself be true
or false. If it is true, you have a most important

LUCILIUS* RECORD 165

witness to your character ; if false, there will be
no witness to the derision you have earned. I may 17
myself appear at present to be either seeking to
throw my net over you or trying to make you rise
to my fly. Take either supposition for true, and
begin, from the example I offer, to fear all flatterers.
Meditate on Virgil's words :

Nowhere is honour safe ;
or on Ovid's :

As far as earth extends, the savage Fury rules j
For crime, methinks, all have conspired ;

or on this sentiment of Menander's — for who has
not put forth the full strength of his indignation 18
on this topic, in abhorrence of mankind's agreement
in rushing toward vice ? All are bad livers, says
the poet, presenting himself on the stage in the
rude character of a raw countryman. He excepts
neither greybeard nor youth, neither man nor woman.
He adds to the charge that it is not individuals or
small numbers that sin, but that wickedness is now
ingrained in society all through. One must flee from
the world and return to oneself, nay, rather one must
escape from oneself. Though you and I are separated
by the sea, I will endeavour to render you some 19
service : placing my hand in yours I will guide
your doubtful steps along the more excellent way.
At this distance I will mingle my talk with yours,
that you may not feel the loneliness. We shall be
united in our noblest part — the spirit. We shall
impart mutual counsel, and, as you hang upon the
lips of your monitor, I will lead you far away from
that province of yours. For I would not have you
put too implicit trust in records of the past, or
become self-satisfied as often as you reflect : I

1 66 PHYSICAL SCIENCE BK. iv

20 have under my jurisdiction a province here which
both maintained and crushed the armies of the
mightiest states, when it was offered as a prize in
that colossal war between Carthage and Rome. It
saw the strength of four Roman generals, in other
words, of the whole empire, massed in one spot ;
it raised high the fortunes of Pompey, brought
Caesar's to their culmination ; transferred the power
of Lepidus to his rivals, and contained the fate of
all. Sicily was an eye-witness of that great spectacle

21 which showed plainly to the world how rapid the
descent from highest to lowest could be, and in how
many different ways great power might be over-
thrown by fortune. For at one and the same time
it witnessed the downfall of Pompey and Lepidus
from the pinnacle of power in opposite ways ;
Pompey had to run from his enemy's army,
Lepidus from his own.

ALTHOUGH Sicily, then, has many wonderful sights
in and around it, I will meantime withdraw
your mind wholly from your own province, and,
passing by all questions relating to it, will direct
your thoughts to a far different scene. In your
society I will resume the inquiry postponed in my
last book, why the Nile overflows in the summer
months. Now, let me remark that the philosophers
have asserted the similarity of the Danube to the
Nile, because its source is unknown and it is
larger in summer than in winter. Both statements
are clearly false. We know for a fact that the
Danube rises in Germany. Again, though the

THE NILE

rise of the Danube begins in summer, it is at a
period when the Nile still remains within its
ordinary limits : the heat is then only beginning,
and the stronger sun toward the latter part of
spring is softening the snows, but it has to melt
them before the Nile begins to rise. During the
remainder of the summer the Danube actually falls
until it reaches its winter size, from which in due
course it begins its rise again.1

II

BUT the increase of the Nile begins in the middle of i
the hot season, before the rise of the dog-star, and
continues till after the equinox. Nature has raised
up this noble river before the eyes of the world,
and has so ordered its inundation of the land of
Egypt that it should occur at the very time at which
the ground is most parched with heat. The earth
thus drinks the more deeply, and imbibes sufficient
to counteract the drought of the whole year. In
the part of Egypt that stretches round Ethiopia,
you must bear in mind, there is either no rain at all
or it occurs only at long intervals, and is insufficient
to give much relief to a land which ordinarily knows
nothing of water from the clouds. It is in the 2
Nile, as you are aware, that Egypt reposes all its
hopes. According to the abundance or scantiness
of its overflow is the leanness or the fatness of its
season. None of its farmers regards the sky, are
the words of your own poem. And why should
I not crack a joke with my dear poet friend, and

1 The meaning of the last clause is taken by some to be : and even falls
below it — a somewhat pointless remark.

1 68 PHYSICAL SCIENCE BK. iv

retort with a verse from his favourite Ovid ? l who
says :

Nor do the herbs make supplication to the rain-god Jupiter.

3 If one could only ascertain at what point in the
course of the river the rise begins, the causes of the
rise would also be discovered. As it is, the river
wanders through great deserts, spreads out into
marshes, among many scattered tribes, before it
is for the first time after its wandering, mazy course
gathered into one near Philae. Philae is a rugged
island, precipitous on all sides ; it is surrounded by
the two branches of the river before they unite to
form the one river which henceforth bears the
designation Nile. The whole city of Philae is
surrounded by the Nile, which after leaving
Ethiopia is a large rather than rapid river.2 Next
in its course are the sandy deserts through which

4 passes the trade route to the Red Sea.2 After
that the Nile enters the Cataracts, a spot famous
for a wonderful sight. The river rises over high
crags that are at several points jagged. The
opposing rocks break up its course and rouse its
utmost force ; as it struggles through the narrows,
swirls show the points where it conquers or is con-
quered. A smooth channel had hitherto conducted
its waters without uproar. Here for the first time
they are roused, and the turbulent cataract leaps
down through the narrow passage quite unlike its

5 former self. Up to that point the stream was thick
and muddy. But once it enters the craggy gorge
it breaks into foam. Its colour is no longer the
natural one, but derived from the ground through

1 The quotation is really from Tibullus.
2 The text is very uncertain.

ii CATARACTS 169

which it has to force its way. When at length it
has struggled through the obstructions, suddenly
deprived of support, it falls from a vast height with a
roar that resounds through all the surrounding
regions. The race planted in that savage place
was indeed unable to endure the din ; their ears
were deafened by the constant crash, and they were
therefore removed from the settlement.

Among the wonderful sights of the river I have
been told of a feat of incredible daring performed by
the inhabitants. Two of them embark in a small
boat, one steering, the other baling out the water.
Forthwith they are violently buffeted from side to side 6
by the furious waves of the rapid river, and at length
reach the narrowest channels, through which they
thread their way till they escape from the craggy
gorge. Then they are carried down along with the
whole volume of the stream, guiding all the time by
hand the rushing craft. At one moment they seem
to stand right on their head ; the spectators are in
great alarm ; one gives them up for lost, and believes
they must be sunk and overwhelmed by such a
mass of water. But finally they are shot out like an
arrow, and are discovered afloat at a point far below
where they had entered the current. The waves in
their fall do not swamp them, but pass them on to
smooth water.

The first rise of the Nile is observed near the 7
island Philae which I have just mentioned. A
short distance from it the river is divided by a
rock in the centre, which the Greeks call the
Inaccessible ("A/Saro?). No foot approaches it
save that of the priestly ministers. Those cliffs first
feel the increase of the river. Then a long distance
below that two crags project, called by the natives

i ;o PHYSICAL SCIENCE BK. iv

the veins of the Nile. A great quantity of water is
shed out by them, but yet insufficient to flood the
land of Egypt. When the date of the sacred
festival comes round, the priests throw into these
fountains a public offering, while the magistrates

8 offer gifts of gold. From this point the Nile,
obviously displaying the fresh energy it has gained,
flows onward in a channel of profound depth, but
is restrained by mountain barriers from spreading
widely beyond its banks. Only when it reaches
Memphis is it released ; and separating into
numerous channels, it roams over the champaign.

In order to regulate the supply, canals are con-
structed by hand, and thus the water is distributed
over all Egypt. At first near its bank the stream is
simply divided ; by and by the waters extend till they
assume the aspect of a wide, swollen sea at rest. The
extent of the country flooded, which embraces the
whole land of Egypt to right and left, deprives the

9 current of all its force. The height of the Nile's
rise determines the expectation of growth for the
year. The farmer is never out in his reckoning ; the
fertility of the land answers unfailingly to the measure
of the river's increase. It spreads a coating of soil as
well as water over the thirsty, sandy ground. As it
comes down swollen, it deposits all its sediment in the
dry, gaping cracks, and spreads over the parched soil
all the rich mud it has brought down. It thus renders
a double service to the land — first, by overflowing
it, and then by coating it with slime. And so any

10 portion that it does not reach lies waste and unsightly.
If the inundation is unduly high, it does damage.

The river possesses this wonderful character-
istic : while all other rivers wash away and exhaust
land, the Nile, though so much larger than the

ii IRRIGATION— ALLUVIAL DEPOSIT 171

rest, far from eating away or rubbing off soil,
actually adds to its vigour; it contains very little
that injuriously affects the soil,1 for by the mud
it brings down, it soaks and binds the sands.
Egypt, in fact, owes to the river not merely the
fertility of the soil, but also the soil itself. It is n
a beautiful sight when the Nile has spread itself
over all the fields. The plains are hidden, the
valleys have disappeared ; only the towns stand out
like islands. In the interior of the country there is
no communication except by boat. The people are
overjoyed the more, the less they can see of their
country. Even when the river has resumed its
normal course, it discharges into the sea by seven
mouths, any one of them itself a sea. Moreover, it
sends out many less famous arms toward either bank.
And then when we look at the monsters it rears,
they are equal to those of ocean in size, and
no less formidable. One may judge indeed of the 12
greatness of the river from the hugeness of the
animals for whose sustenance it provides food in
abundance, and for whose free movements it
affords room. Balbillus, a most excellent man who
has distinguished himself in every walk of letters,
has recorded that during his own government of
Egypt he himself saw in the largest mouth of the
Nile, the Heracleotic, the strange sight of what
may be called a pitched battle between dolphins,
coming up from the sea, and crocodiles meeting
them in front from the river. The crocodiles 13
were in the event vanquished by the inoffensive
animals with harmless bite. It happened on this
wise : The upper part of the crocodile's body is
hard, and cannot be pierced by the teeth even of

1 Or, its least service is that it tempers the soil.

172 PHYSICAL SCIENCE BK. iv

larger animals ; but the lower part is soft and
tender. The dolphins dived in the fight and
wounded the belly of the crocodiles with the pro-
jecting spikes they carry on their back ; then driv-
ing home the stroke, they fairly cut up the enemy.

14 When a number of the crocodiles had been opened
out in this fashion, the remainder, to adopt military
language, wheeled their line and retreated. The
battle was not to the strong, the fleeing creature
successfully resisted the daring, the most daring fled
before the timid ! Nor is it by any peculiar virtue
of stock or blood that the islanders from Tentyra
beat the crocodiles, but merely through pluck and
contempt of them. They take the offensive against
them, and as the crocodiles try to escape they lasso
them and drag them ashore. At the same time
many of the hunters lose their lives through lack of
nerve in the chase.

Theophrastus assures us that the Nile has at

15 times brought down sea water. It is a well-
established fact that for two successive years, the
tenth and eleventh of the reign of Cleopatra,
there was no rise in the river. People say that
this was an intimation of the impending fall of
its two rulers. For as a matter of fact, the rule
of Antony and Cleopatra did fall. At an earlier
period the Nile did not rise for nine whole years,
according to the statement of Callimachus.

16 But I must now go on to inquire into the ex-
planations of the occurrence of the rise of the Nile
in summer ; and I will begin with the most ancient
of them. Anaxagoras asserts that the snow melting
on the peaks of Ethiopia is constantly running
down to the Nile. All antiquity shared the same
view, which is recorded by Aeschylus, Sophocles,

ii RISE OF NILE— SNOW 173

and Euripides. But many proofs make it plain that 17
it is a mistaken one. First of all, the blackened
complexion of the people shows that Ethiopia is
exceedingly hot. So do the habits of the Trog-
lodytes (cave-dwellers), who for coolness have under-
ground houses. The rocks glow with heat as if a
fire had been applied, and that, not only at mid-day,
but even toward nightfall. The dusty ground is so
hot that no foot of man can endure it. Silver is
unsoldered.1 The joints of statues are melted. No
coating of plated metal will stick on. The south ig
wind, too, coming from that tract of country, is the
hottest of all winds. None of the animals that go
to earth in winter ever hibernates there. Even in
midwinter the serpent is seen above ground in the
open. At Alexandria, too, which lies far north of
this excessive heat, snow does not fall ; but the upper
regions have not even rain.

How then, I ask, could a district exposed to
such broiling heat receive a snowfall sufficient to
last through a whole summer ? No doubt some of 19
the mountains in Ethiopia, as well as elsewhere,
intercept snow ; but there can never be a greater
fall than in the Alps, or the peaks of Thrace,
or the Caucasus. It is in spring, however, or
early summer, that the rivers that flow from the
European mountains are swollen ; subsequently
during winter time they decrease. The reason,
of course, is that the rains in spring wash off so
much of the snow, and the first heat of summer
soon scatters the remnants. Neither the Rhine,
nor the Rhone, nor the Danube, nor yet the Caystrus
is liable to the catastrophe of an overflow in winter;
their increase is in summer, though in those northern

1 Some render — is dissolved and gives off its lead.

174 PHYSICAL SCIENCE BK. iv

peaks where they rise the snow lies very deep.

20 The Phasis, too, and the Dnieper would swell
during summer if snows had the power of rais-
ing the rivers high in spite of the heat of that
season. Besides, if this were the cause of the
flooding of the Nile, its stream would be fullest in
early summer ; for that is the period when the snow is
deepest and least impaired, and when from its soft-
ness the thaw is quickest. The Nile, however, has
a regular increase to its stream during four months.

21 If one may believe Thales, the Etesian winds
hinder the descent of the Nile and check its course
by driving the sea against its mouths. It is thus
beaten back, and returns upon itself. Its rise is not
the result of increase : it simply stops through being
prevented from discharging, and presently, wherever
it can, it bursts out into forbidden ground. Euthy-
menes of Marseilles bears corroborative testimony :
I have, he says, gone a voyage in the Atlantic
Sea. It causes an increase in the Nile as long as
the Etesian winds observe their season. For at
that period the sea is cast up by pressure of the

22 winds. When the winds have fallen, the sea is at
rest, and supplies less energy to the Nile in its
descent. Further, the taste of that sea is fresh, and
its denizens resemble those of the Nile. Now, if the
Etesian winds, as alleged, stir up the Nile, why, I
should like to know, does its rise begin before them
and last after them ? Moreover, it does not rise
higher in proportion to the violence of their blast.
Nor does it swell and fall according as they blow
furiously or gently. All which would happen if it
derived from them the strength of its increase.

23 Then, again, the Etesian winds beat on the shore of
Egypt, and the Nile conies down in their teeth :

n ETESIAN WINDS 175

whereas, if its rise is to be traced to them, the river
ought to come from the same quarter as they do.
Furthermore, if it flowed out of the sea, its waters
would be clear and dark blue, not muddy, as they are.
Add to this that Euthymenes' evidence is refuted
by a whole crowd of witnesses. At such a time when
foreign parts were all unknown, there was oppor-
tunity for falsehood : people like Euthymenes had
scope for giving currency to travellers' myths. But
nowadays the whole coast of the sea beyond
Gibraltar is visited by trading vessels : none of the
traders tell us that the Nile rises there, or that the sea
in the Atlantic tastes differently from what it does
elsewhere. The very nature of the sea forbids 24
belief in the story that it is fresh : the freshest water
is always lightest, and as such attracted by the sun
in evaporation : the residuum, sea, must be salt.
Besides, why, on this theory, does the Nile not rise
in winter ? The sea may be raised at that season
by storms too, which are considerably greater than
the Etesians ; the latter are comparatively moderate
in their force. Besides if the source were derived
from the Atlantic Ocean, Egypt would be flooded
all at once ; but, as a matter of fact, the increase is
very gradual.

Oenopides of Chios has another explanation : he 25
says that in winter heat is stored up under the
ground ; that is why caves are then warm, and the
water in wells is less cold. The veins of water are
dried up by this internal heat, he thinks. In other
countries rivers swell through rain : but the Nile,
being aided by no rainfall, dwindles during the
rainy season of winter, and by and by increases in
summer, a season at which the interior of the earth
is cold, and the frost returns to the springs. Now, 26

176 PHYSICAL SCIENCE BK. iv

if that were true, rivers in general would increase in
summer, and all wells would then have greater
abundance of water. Besides, it is not true that
there is an increase in the heat underground in
winter. Water and caves and wells are warm at
that season because they do not admit the frosty air
from without. Thus, they do not possess heat, they
merely exclude cold. For the same reason they
are chilly in summer, because the air heated by the
sun is drawn off to a distance, and does not pene-
trate to them.

27 The next account is that of Diogenes of Apollonia.
It runs thus: The sun attracts moisture; the earth
drained of it replenishes its supply in part from the
sea, in part from other water. Now, it is impos-
sible that one land should be dry and another over-
flowing with moisture. The whole earth is full of
perforations, and there are paths of intercommunica-
tion from part to part. From time to time the dry
parts draw upon the moist. Had not the earth
some source of supply, it would ere this have been
completely drained of its moisture. Well, then, the
sun attracts the waves. The localities most affected

28 are the southern.1 When the earth is parched, it
draws to it more moisture. Just as in a lamp the
oil flows to the point where it is consumed, so the
water inclines toward the place to which the over-
powering heat of the burning earth draws it. But
where, it may be asked, is it drawn from ? Of
course, it must be from those northern regions of
eternal winter, where there is a superabundance of

29 it. This is why a swift current sets from the Black
Sea toward the Lower Sea, without interruption,
and not, as in the case of other seas, with alternate

1 The text is uncertain ; the general meaning is, however, plain.

ii OTHER EXPLANATIONS 177

flow and ebb of tide ; there is always a descending
flood in the one direction. Unless this took place,
and these routes supplied the means whereby what
is lacking may be bestowed on each land, and what
is superfluous may be given off, the whole earth
would ere now have been either drained or flooded.
Now, one would like to ask Diogenes, seeing the 30
deep and all streams are in intercommunication, why
the rivers are not everywhere larger in summer.
Egypt, he will perhaps tell me, is more baked by
the sun, and therefore the Nile rises higher from
the extra supply it draws ; but in the other coun-
tries, too, the rivers receive some addition. Another
question — seeing that every land attracts moisture
from other regions, and a greater supply in propor-
tion to its heat, why is any part of the world without
moisture? Another — why is the Nile fresh if its
water comes from the sea? No river has a fresher
and sweeter taste.

Ill

I SHOULD be somewhat too bold if I were to assure i
you as on oath that hail is formed in the sky much
in the way ice is with us, only that in the former
case a whole cloud is frozen. So I may regard
myself as a witness only in the second degree — one
of those who say not that they have actually seen
but have been informed. Or, I may, for once, do as
the chroniclers do. After lying at large to their
heart's content, they fix on some one point for which
they refuse to vouch, adding: Evidence of this
will be found in the authorities. So, if you do 2
not believe me, Posidonius will vouchsafe to you
his authority both for the statement I have made,

N

1 78 PHYSICAL SCIENCE BK. iv

and for one that I am going to make. He will assure
you, as confidently as if he had witnessed the pro-
cess of formation, that hail is formed from a cloud
that is charged with rain, and has already turned
into moisture. You can discover without a tutor
why the hail is round if you observe that drops of

3 all kinds tend to become globular. This is seen,
for example, in looking-glasses, which gather mois-
ture from the breath, as well as in cups, and any
other smooth surface bedewed with it. So, too,
in the leaves of grass or trees, any drops that
adhere take a circular form.

What is harder than rock, what softer than water ?

Yet the hard rock is hollowed by drops of the soft water ;

or, as another poet tells us :

The drip by its fall hollows the stone :

4 and this hollow is itself round. Whence it is
evident that its shape resembles this drip which
hollows it out, sculpturing the spot to its own
form and character. Besides, the hail, even were
it not of this shape, might be rounded in its
fall, and worn equally on all sides into globular
form as it is again and again whirled round in
its descent through the space of thick air it
traverses. Snow, on the contrary, cannot be affected
thus, because it is not so solid, being indeed
very much scattered, and falling from no great
height. It has its source in the neighbourhood of
the earth, and its descent is of no great distance
through the air, but starts from a point quite close

5 by. Why should I not allow myself the same licence
as Anaxagoras in differing from my authorities ?
Nowhere can equality of rights be claimed with
more propriety than among the philosophers. Hail

HAIL

179

is simply ice held suspended in mid-air ; snow is a
floating congealed mass of the nature of hoar-frost.
I have already said that the difference between
water and dew is reproduced in the difference of
hoar-frost and ice, and, in like manner, in that
between snow and hail.

IV

I MIGHT take leave of the question here, holding i
that I had finished it. But I will give you good
measure, and, having begun to trouble you with
my speculations, I will discuss everything con-
nected with the topic. One of the cognate ques-
tions is, why in winter there is snow but no
hail, while in spring, after the worst of the cold
is over, there are falls of hail. For let me be
deceived for your benefit, though I may say I am
fully persuaded of the truth of what I am about
to affirm. I lend always a credulous ear to these
trivial falsehoods ; perhaps they deserve to be
punished by having one's mouth stopped, but they 2
hardly call for the putting out of one's eyes ! In
winter the atmosphere is stiff, and is therefore not
as yet capable of being converted into water, but
only into snow, to which the atmosphere is more
akin. But when spring begins, a greater variation
of the atmosphere ensues, and, the sky being warmer,
the drops are larger. Therefore, as our poet Virgil

says :

When rain-charged spring descends,

there is a more violent change in the atmosphere,
which everywhere opens up and relaxes through the
action of the mere warmth. For this reason the
clouds that are carried to earth are heavy and large 3

i8o PHYSICAL SCIENCE BK. iv

rather than lasting. Winter rain is thin and per-
sistent. The fall often occurs in the form of small,
fine rain, with an admixture of snow. We call it
a snowy day when the cold is intense and the sky
leaden. Besides, when the north wind doth blow,
producing its characteristic sky, there may be fine
rain. With south wind the rain is more persistent,
and the drops heavier.

1 ONE position held by the philosophers of my sect
I neither venture to adopt on account of its seeming
weakness, nor yet can I pass it by without mention.
Where can be the harm of suggesting even an
improbable explanation when one has such an
indulgent judge ? If we are to apply a test like the
pyx to every argument, we shall soon cease to
advance any hypothesis at all and be reduced to
dumbness. There are very few statements that
pass unchallenged. All the rest have to assert
their rights before they can win their case. Well,
the assertion of the Stoics is, that all the ice-bound
region about Scythia and Pontus and the northern
quarter is released from its chain in spring ; then the
frozen rivers resume their course, then the mountains
melt the snows in which they have been buried.
It is quite conceivable, therefore, that cool airs arise
from this and mingle with the atmosphere of spring.

2 They add a proof which I have never tested nor
have any intention of testing. You, too, I fancy,
however anxious you may be to ascertain the truth,
will be cautious about making such a trial of snow.
The feet are said to suffer less pain when one treads
on hard, solid snow than if the snow were slushy

v ITS SUPPOSED ORIGIN 181

and half melted. Well, then, if the Stoics do not
lie, all the currents of air wafted from those northern
parts, when the snow has now been dislodged and
the ice is breaking up, condense and bind the
atmosphere of the southern region which is already
becoming warm and moist. So what was going to
be rain becomes, through the violence done by the
cold, hail instead.

VI

I CANNOT refrain from trotting out all the silly i
fancies of our Stoic friends. The assertion in
question is that there are some people skilled in
observing the clouds who foretell when a hail
shower is coming on. They gather this just from
experience by marking the colour of the clouds
and noting which was on previous occasions followed
by hail. It seems incredible that at Cleonae there
were hail-guards (xa\a£o<f>v\a/ce<;) appointed by the
state to look out for the approach of hail. When
they had given the signal that the hail was close at
hand, what do you think ? that people ran off to get
their overcoats or cloaks ? Nay, they each offered 2
sacrifice as fast as they could, one a lamb, another
a chicken. Forthwith, those clouds after getting
a little taste of blood drew off in another direction.
You smile ! There is something to make you smile
more broadly. If one had not a lamb or kid by,
one laid hands upon oneself to an extent that could
be done without serious damage. You must not think
the clouds greedy or cruel ; one merely pricked one's
finger with a well-sharpened style and made atone-
ment with this blood. The hail as invariably turned
away from his little plot as from the estate of the

1 82 PHYSICAL SCIENCE BK. iv

man who had prevailed upon it through the offering
of greater victims.

VII

1 CERTAIN writers seek for a rational explanation of
this practice. One school, adopting the only line
that comports with philosophy, deny the possibility
of making any bargain with hail and buying off
storms by paltry presents, true, though it be, that
gifts overcome even gods. Others affirm their
suspicion that blood itself contains a virtue potent
enough to avert and repel a cloud. But how, I ask,
should a drop or two of blood possess a virtue to
reach on high and influence the clouds ? Is it not
much easier to say, the whole thing is a parcel of

2 lies ? But Cleonae was strict in dealing with its
warders who had received charge of looking out
beforehand for the storm, if it happened that
through their neglect the vineyards had been beaten
down or the crops laid. And among ourselves, too,
at Rome the laws of the Twelve Tables introduce
safeguards against the blighting of a neighbour's
crops by charms. Antiquity as yet untutored enter-
tained the belief that rain could be attracted or
repelled by incantations. The impossibility of such
fancies is so evident that one need not enter a
school of philosophy in order to be taught how to
disprove them.

VIII

I SHALL add one more remark which you will be
very glad, I am sure, to approve and applaud. It
is asserted that snow is formed in the part of the

vni HAIL AVERTED BY BLOOD 183

atmosphere near the earth. This layer has more
heat than any other, and that for three reasons.
One is that all evaporation from the earth, contain-
ing as it does much dry, glowing matter, is always
the hotter, the more recently it has left the ground.
The second is that the sun's rays are reflected from
the ground and return upon themselves. Their
reflection heats up the parts next the ground, which
thus have more warmth from getting the sun's heat
twice. The third reason is that the upper regions
are more subject to wind ; but all places that are
sunk are less wind-swept.

IX

To the foregoing Democritus' explanation falls to be
added. Every body receives heat more quickly and
retains it longer in proportion to its solidity. For
example, if three vessels, of copper, glass, and silver
respectively, are set in the sun, the heat will
penetrate the copper one soonest and will remain
in it longest. The reason why Democritus is of
this opinion may also be added. In the bodies,
he says, that are harder, more compact, and dense,
the openings must of necessity be smaller than in
others, and in each of the openings the film of
air must be thinner. It follows that just as smaller
baths and smaller cylinders are heated more rapidly
than others, so these concealed apertures, so small
as to elude the eye, both feel the heat more quickly,
and by reason of this same smallness of calibre
give back more slowly the heat they have received.

184 PHYSICAL SCIENCE

THIS long preamble leads up to the point we are
now examining. All air is the denser the nearer
it is to the earth. In water and other liquids the
dregs are always at the bottom ; in like manner
in the atmosphere the thickest portions settle down
to the lowest part nearest the earth. But it has
already been proved that all things, in proportion
as they are denser and more compact in their con-
sistency, guard more faithfully the heat they have
received. On the other hand, the more exalted
the air is, and the farther it is withdrawn from the
pollutions of earth, the less contaminated and the
more pure it is ; and so it does not retain the sun's
rays, but transmits them as if through a vacuum ;
hence it is less warmed by them.

XI

1 BUT contrariwise, certain persons assert that moun-
tain peaks ought to be warmer in the degree in
which they are nearer the sun. Such people seem
to me, however, to be astray in supposing that the
Apennines and the Alps and other mountains
famed for their exceeding height are so greatly
elevated that their size should enable them to feel
in any special way the sun's proximity. No doubt
those are lofty heights so long as the standard of
comparison is ourselves. But when one regards
the size of the universe, the lowness of them all
becomes evident. Compared with one another,

2 mountains are surpassed or surpass in height. But

xi STANDARDS OF HEIGHT 185

nothing on earth is elevated so high that even the
greatest of objects should be any1 appreciable
portion in comparison with the whole universe.
Were this not so, we should not be in the habit
of saying that the whole earth is a ball. The
distinctive mark of a ball is a certain uniform
rotundity, much the same as the uniformity seen in
a football or cricket ball.2 The seams and chinks
constitute no great objection to the ball being
described as symmetrical on all sides. As in a 3
playing ball, those spaces do not in any way prevent
the appearance of roundness, no more, in the earth
at large regarded as a sphere, do lofty mountains,
whose height is lost in a comparison with the whole
world. A person who says that a higher mountain
ought to be warmer from receiving the sun's rays
at a shorter distance, may just as well say that a
taller man should be heated sooner than a dwarf,
and his head sooner than his feet ! But any one who 4
will take the trouble to judge the universe by its
proper standard, and who will reflect that this earth
occupies but a single point in space, will not fail
to perceive that nothing on earth can be of such
eminence as to be more sensible than others of
the influence of the heavenly bodies, as if it had
approached their neighbourhood. Those mountains
at which we gaze up, their summits weighed down
with eternal snows,' are none the less but low and
humble. While it is true that a mountain is nearer
the sun than is plain or valley, yet it is in the same
sense as javelin is spoken of as thicker than javelin,
tree as larger than tree, mountain than mountain.

1 The argument seems to require ulla — any, instead of nulla = no.

2 The specific references are not contained in the Latin words ; the modern
counterpart of the Roman games of ball serves, however, to bring out the
meaning of the illustration.

1 86 PHYSICAL SCIENCE BK. iv

5 Accordingly to that mode of speech of yours, one
tree must be said to be nearer the sky than another ;
which is false, because among puny objects there
cannot exist great differences except while they are
compared with one another. When one comes
to compare such objects with the mighty frame of
things, it is immaterial how much the one is bigger
than the other, because the very small things, how-
ever great the differences among them, are quite
dwarfed by comparison with the universe.

XII

BUT to return to my main theme ; for the reasons
which I have detailed, most authorities are satisfied
that snow is formed in the part of the atmosphere
which is in the vicinity of the earth. It is less
compacted than hail because congealed through
less intense cold. For the air near us has at
once too much cold to allow its passage into water
and rain, and at the same time too little to get
hardened into hail. Through this moderate but
not too intense cold the water is massed and turns
into snow.

XIII

WHY, I fancy I hear you say, do you pursue so
laboriously those frivolous explanations of yours,
by which no one is made either more accomplished
or more virtuous ? You tell us all about the
formation of snow ; it would be far more to the
point that we should be told why it is a

xiii CAUSE OF SNOW 187

wrong thing for snow to be bought.1 I see you
wish to drag me into a dispute with luxury, a
quarrel of daily occurrence that never leads to any
tangible result Let us withal brace ourselves for
the struggle ; even if luxury win the day, it must
find us fighting and resisting to the death.

Well then ! do you suppose that the examination
of nature, irrelevant as it may appear, makes no
contribution to the object you have at heart ? When 2
we inquire how snow is formed, telling that its
character resembles hoar-frost, containing more air
than water, do you not think that it is a reproach
upon the epicures ? If it is a scandalous thing to
buy water, they are still worse, for they do not
get even water [but chiefly air] for their money.
Let us, I say, inquire rather how snow is formed
than how it is preserved. The means of pre-
servation have already been discovered ; not
content with racking wines of vintage, arranging
them by flavour and age, we have devised means
of compressing snow to overcome the power of
summer, and of protecting it by the coolness of
the icehouses from the hotness of the season.
And what have we accomplished by all our anxious 3
efforts ? The privilege of buyLig water that we
might have got for nothing ! We are vexed that
we cannot buy air and sunlight, and that the
atmosphere all around streams in easily and un-
bought upon the fastidious and the rich. How
badly nature treats us in leaving anything that is
common property ! Upon this other element,
water, which nature has allowed to flow for the
free use of mankind, and which she has given the

1 I.e. the moral turpitude of sinking into such debased luxury as to require
snow should be set forth rather than mere theories of the formation of snow ;
the ethical should take precedence of the physical.

1 88 PHYSICAL SCIENCE BK. iv

whole world to drink, this that she has shed forth
with lavish prodigality for the service alike of man
and of beasts and birds and the very laziest of the
animal creation — upon this, luxury, with ill-conceived

4 ingenuity, has managed to put a price. In fact,
nothing can please luxury unless it is expensive.
Water was the one thing that used to bring down
the rich to the level of the common herd, in which
the wealthy could not surpass the very poorest.
Those who found their riches a burden have devised
a plan whereby water should become a luxury.

How it has come about that no running water
should be thought cool enough, I will now explain.
As long as the stomach is healthy and is able to
relish wholesome food, with which it is satisfied and
not overloaded, it is quite content with the natural

5 stimulants. But when through daily indigestion it
suffers from the heat not of the season but of its
own indulgence, when habitual drunkenness has
taken firm hold on the organs of life, and turns into
bile which parches the intestines, then it becomes
necessary to seek out some means of quenching the
internal heat. Water merely inflames it, the disease
is aggravated by the remedies. Therefore, for
this purpose they use snow for drink, not only in
summer, but even in the depths of winter. The
cause can be no other than the internal complaint.
Digestion is spoiled through indulgence ; respite is
never given it in which to rest. Breakfast is
heaped upon a supper prolonged till daylight.
While the revellers are literally bursting with the
lavishness and variety of the courses, heavy
drinking plunges them still deeper in the mire.

6 Then the continuous excess causes heartburn
from the food previously consumed, and inflames

xin DEGRADING LUXURY 189

the constant craving for some new stimulant. So,
though they protect the banqueting hall with
draperies and windows, and seek by roaring fires
to banish winter's colds, none the less the lan-
guishing appetite, exhausted by its own heat,
yearns for something new to revive it. Just as we
sprinkle cold water on people who have lost con-
sciousness through a fainting fit, in order to bring
them back to their senses ; so the internal organs,
numbed through excess, are past feeling, unless
they are smitten by the parching, as it were, of
more violent cold. Hence it is, I say, that not 7
content even with snow, they call for ice, as if the
stimulant were the more certain from its solidity,
and melt it with repeated douches of water. The
ice, too, is not taken from the surface, but, that it
may have greater virtue and more lasting cold, it
is dug out of the depths of the pile. Thus it is
not even of uniform price ; but water actually
has its hawkers and — alas the day ! — a varying
price. The Lacedaemonians once banished the
perfumers from their city, ordering them to quit
the country with all speed, because they were
wasting the oil supply. What would they have 8
done, I wonder, if they had seen cold stores for
preserving snow and such an army of beasts
employed in carting water, whose colour and
flavour are often all spoiled by the straw in which
it is kept ?

Good heavens ! how easy a thing it is to
quench the thirst of health ! But what feeling can
jaws retain that are deadened and numbed by
scalding food? These epicures can have nothing
cold enough, neither can they have anything hot
enough. Mushrooms taken from the fire and hastily 9

1 90 PHYSICAL SCIENCE BK. iv

dipped in their special sauce are crammed down
the throat almost boiling, and the heat has to be
allayed by draughts chilled in snow. One may see,
I tell you, slender youths, rigged out in cloaks and
mufflers, pale and sickly, not merely sipping the
snow, but actually eating it, throwing little pieces
of it into their glasses to prevent them from getting
warm during the intervals of drinking. Do you
10 call that honest thirst ? It is fever, the more acute
too as it cannot be detected by the pulse or the
wonted heat that overspreads the skin. The very
heart is dried up by that incurable malady, luxury,
whose habitual weakness and unsteadiness are
turned into endurance and obstinacy. Don't you
know that habit dulls the force of everything ? The
snow in which you are now, so to speak, swimming l
has through custom and the daily slavery of the
stomach come to occupy the place of water. You
must now search for something colder still ; for a
stimulant that is habitual is no stimulant at all.

1 Which you now use in your baths.

BOOK V

WHICH TREATS OF WINDS AND
ATMOSPHERIC MOVEMENT IN GENERAL

191

I

WIND is the atmosphere in motion. Some have i
put the definition thus : Wind is the atmosphere
in motion in one direction. The latter seems the
more accurate, because the atmosphere is never so
still as not to be in agitation of some kind. In a
similar way the sea is called calm when it is only
slightly moved and does not set in a particular
direction. Thus, if you read the verse :

When the winds slumbered and the sea was still,

you must bear in mind that the sea was not actu-
ally still, but heaved gently ; and that it is called 2
calm in a comparative sort of way because it
receives no distinct impulse to this side or to that.
The same opinion is likewise to be adopted in
regard to the atmosphere : it is never absolutely
motionless, even though it be still. This you may
gather from the following observation : When the
sun pours into any circumscribed space, one sees
minute particles carried through the air in different
directions, some up, some down, meeting each other
in a great variety of ways. Therefore, if one say : 3
a wave is an agitation of the sea, one will very
imperfectly express what is meant, because even
when at rest the sea is agitated. But one will more
than sufficiently safeguard oneself if the definition

193 O

i94 PHYSICAL SCIENCE BK. v

be : a wave is an agitation of the sea in one
direction. So in the subject which at the moment
forms our special topic, the definition will not be
unduly restricted if one is careful to say : wind
is the atmosphere flowing in one direction ; or, wind
is atmosphere flowing through some impulse, or, is
the force of the atmosphere going in one direction,
or, is a rush of the atmosphere more forcible than
usual in some one direction. I am aware of a
criticism that may be made in regard to the first
4 definition. What need is there to add that it is in
one direction that the atmosphere flows ? For
surely whatever flows, flows in one direction. No
one says that water flows if there is simply an
internal movement of it, but only if it is borne in
a particular direction. So a substance may be in
motion and yet not flow ; but, on the other hand, it
cannot flow except in one direction. Well, if, on
the one hand, the shorter definition is free from cavil,
let us employ it ; but if, on the other, any one is a
stickler, let him not omit the phrase whose addition
will serve to preclude all ambiguity. Now that we
have sufficiently discussed our terms, let us come to
grapple with our problem at closer quarters.

II

DEMOCRITUS avers that when there are many
particles, which he calls atoms, in a small empty
space (i.e. vacuum), wind is the outcome. But, on the
contrary, when the space is large and the particles
few, there is a still peaceful condition of the atmo-
sphere. To illustrate : in the market square or in
a side street as long as there is a sprinkling of

ii WIND— ATOMIC THEORY 195

people there is no disturbance as one walks along
it ; but when a crowd meets in a narrow space, then
they jostle against each other, and quarrelling
arises. Similarly in this space which surrounds our
earth ; when many bodies have crowded a very
small portion, it is unavoidable that they should
jostle one another and be driven back and forward,
and be intertwined and squeezed. Hence results
wind ; the particles that were struggling have had
to give way, and after being tossed about and
remaining in suspense for a long time they at
length lean their weight toward one side. But when
a few bodies occupy a large roomy place, they can
neither ram each other nor be jostled by one
another.

Ill

THE falsity of this view may be inferred merely i
from the fact that wind by no means invariably
accompanies a cloud-laden atmosphere, and yet
more particles have gathered at that than at any
other time in a narrow space, where they pro-
duce condensation and heaviness in the clouds.
Besides, in the neighbourhood of rivers and lakes
cloud is frequent from the confinement and accu-
mulation of particles, and yet there is no attendant
wind. Indeed, sometimes such a darkness over-
spreads the place that the view of objects in the
immediate vicinity is cut off; which would never
happen unless numerous particles were massed in
a small space. Yet no period is more free from 2
wind than a period of cloud. Add now a con-
sideration of an opposite character : When the sun
rarefies at his rising the thick dank morning air,

196 PHYSICAL SCIENCE BK. v

then a breeze springs up ; the particles have got
more room now, and the thickly packed crowd of
them is broken up.

IV

1 BUT how, you will say, are winds then formed, for
you won't deny that they are formed ? Not in any
single way, I reply. Sometimes the earth herself
emits a great quantity of air, which she breathes out
of her hidden recesses. At other times a great
and long -continued evaporation drives the emis-
sions from the depths up on high, where the ,change
which the mixed breath undergoes issues in ^ wind.
A suggestion has been made which I cannot make
up my mind to believe, and yet I cannot pass over
without mention. In our bodies food produces
flatulence, the emission of which causes great
offence to one's nasal susceptibilities ; sometimes a
report accompanies the relief of the stomach, some-

2 times there is a more polite smothering of it. In
like manner it is supposed the great frame of things
when assimilating its nourishment emits air. It is
a lucky thing for us that nature's digestion is good,
else we might apprehend some less agreeable con-
sequences. Is it not, then, nearer the truth to say
that numerous particles are constantly borne up
from every part of the world ; and when they are
accumulated and subsequently begin to be rarefied
by the sun, wind starts up ? It is a general prin-
ciple that anything contained in a narrow space
when it expands tries to get more room.

E VAPOR A TION AS CA USE 1 9 7

WELL, then, do I ask you to believe that evapora- i
tion from land and water is the sole cause of wind ?
Do I affirm that it produces a weight in the atmo-
sphere, the breaking up of which causes a rush of
air ? that at that moment what was previously dense
and stationary gets rarefied and strives, as its
nature requires, to obtain a wider space ? I do
approve of this as sometimes the explanation. But
there is a far truer and more potent one, to wit,
that the atmosphere by its constitution possesses a
native capacity of movement, this power not being
derived from an external source, but being like
others of its powers inherent. For can you suppose 2
that we men have been endued with strength to
move about, while the atmosphere has been left
sluggish and immovable ? Water, too, has its own
motion, even though the winds are at rest ; other-
wise it could not produce animal life. We see also
forms of vegetable life like moss produced by
water, and certain kinds of herbage floating on its
surface.

VI

WELL, then, I take it, in water there resides some
vital principle. In water, did I say ? Why, fire,
the universal destroyer, has a creative function ; it
may not seem a likely thing, but all the same it is
but the truth that some animals are generated by
fire. The atmosphere, then, possesses some power
of this kind ; and that is why it sometimes grows
thick, sometimes expands and throws off impurities,

1 98 PHYSICAL SCIENCE BK. v

sometimes contracts, at others opens up and dis-
perses. There is thus the same difference between
air and wind as between lake and river.1 There are
occasions when the sun is the sole cause of wind, as
he rarefies the stiff atmosphere and opens it out
from its thick contracted state.

VII

HAVING spoken of the winds in general, let us now
proceed to the discussion of individual winds.
Perchance the discovery of the time and place of
their origin will conduce to the discovery of their
manner of formation. First, then, let us look at
breezes before dawn, which are borne either from
rivers or hollow valleys or from some bay. None
of these winds lasts long, but falls when the sun has
got stronger ; nor is it carried up out of sight of the
earth. This class of wind sets in in spring, and
does not last beyond summer. It comes chiefly
from a quarter where there are spaces of water
and mountains. Plains, for instance, may have
abundance of water, and yet they have no breeze ;
I mean a breeze strong enough to be called wind.

VIII

How, then, is a blast of this kind, which is called
by the Greeks a gulf breeze (eyico^ias), formed ?
This is the theory of them : All the exhalations of
marshes and rivers — and they are abundant and
constant — form by day the sun's nourishment. By
night, however, there is no drain on them, and they

1 This remark would have been more apposite in Chap. I. , above ;
possibly that is its correct place.

vin THE GULF BREEZE 199

are enclosed by the mountains and accumulate
in one quarter. When they have filled up this
quarter and can no longer find accommodation
in it, but are squeezed out on one side and move
in a particular direction, then you have the
wind. It inclines, of course, toward the side to
which it is invited by the freer exit, and by the
openness of the place toward which the accumu- 2
lated elements can rush. A proof of this is that a
wind of this kind does not blow in the early part of
the night. At that time the gathering only begins,
but by daybreak it has reached the full, and seeks
relief by flowing off. It chooses its exit by pre-
ference where there is the largest empty space and
a great expanse of open. It is stimulated by the
rays of the rising sun striking on the chilly air.
Even before he makes his appearance his light of
itself has an influence. The sun does not at that
stage, it is true, drive away the atmosphere with his
beams ; still, he already attacks and harasses it by 3
the shafts of light he sends before him. When he
comes out himself in his power, part of the
gathering is carried off to a greater altitude, part is
dissipated by his heat. Wherefore power is not
granted to these winds to continue longer than the
morning. All their strength collapses at sight of
the sun. Even if their blast is somewhat violent,
yet they begin to subside as mid-day approaches ;
in fact, the breeze l never lasts as long as noon. Any
other variety of the breeze is weaker and shorter in
duration ; they vary according as the causes to which
they owe their origin are more or less powerful.

1 The precise meaning of this and the following sentence is doubtful ; one
would suspect that the latter originally ran — varieties of the breeze are longer
or shorter in duration according as, etc.

PHYSICAL SCIENCE BK. v

IX

1 BUT why, again, are winds of this nature stronger
in spring and summer ? For during the remainder
of the year they are very light, never rising
sufficiently to fill the sails of a boat. The reason is
that spring is a wetter season. There is at that
time more evaporation going on, both from the
abundance of water lying about, and from the
saturation of the ground to overflowing through
the moist character of the sky. And the reason
why this wind is equally prevalent in summer is
that the heat of the day remaining after sundown
and lasting during a great part of the night draws
out exhalations, and attracts more forcibly any of
them that are wont to be given off spontaneously
by the ground. But subsequently the heat has not

2 sufficient strength to use up what it drew out. This is
the reason, I say, why the soil and its moisture give off
for a longer period [at certain seasons] the particles
derived from the earth's wonted emanations and ex-
halations. The sunrise produces wind by its stroke
as well as by its warmth. For, as I have already
said, the light which precedes the sun does not as yet
heat up the atmosphere, but merely smites upon it ;
being smitten the air retires to one side. And yet I
cannot go so far as to admit that the light is quite
devoid of heat, inasmuch as it is derived from heat.
Probably it does not contain as great an amount as
would appear from its effect. Still, it accomplishes
its own task by separating and rarefying the dense

3 exhalations. Moreover, places which through some
disservice of nature are so shut in that they cannot
receive the direct rays of the sun, even they, I say,

SEASONAL WINDS— ETESIANS

are heated somewhat by the dull cloudy light that
can pierce to them and are less rigid during the
day than by night. Furthermore, all heat naturally
dispels cloud and drives it off from itself. There-
fore the sun likewise has the same effect. For that
reason some people suppose that the blast must
come from the direction in which the sun lies. But
this opinion is manifestly false, seeing that the
breeze sets in any direction, and one can sometimes
sail right toward the sunrise with all canvas set.
That could not happen if the wind were always
coming from the direction of the sun.

THE Etesian winds, too, which some drag into the i
discussion, do not give much support to their con-
tention. First, I will tell you what their opinion is,
and, secondly, why it is not mine. The Etesians,
say they, do not blow in winter, because at the
season of the shortest days the effect of the sun
ceases before the cold is overcome. So, snow
accumulates then and freezes hard. In summer
the Etesian winds begin to blow at the time
when the day is lengthened out and the sun's
rays come down straight upon us. Probably, there-
fore, the snows smitten by the greater heat exhale
more moisture. The earth likewise breathes more
freely when uncovered and relieved of the snow.
So more particles issue from the northern portion of 2
the heavens, and are wafted toward our quarter,
which lies lower and is warmer. From this the
Etesians derive their impulse ; wherefore they begin
at the summer solstice, and do not blow strongly

PHYSICAL SCIENCE

after the rise of the Dog-star, because by that time
a great part of the cold northern exhalations has
been carried down to our regions. But when the sun
has changed his course he still directs his beams
straight down on our hemisphere ; and one part of
the air he attracts, but another he thrusts before
him.1 Thus the blast of the Etesians breaks the
force of the summer heat, protecting us from the
full severity of the most broiling months.

XI

I MUST now, as I promised, tell you why the Etesian
winds do not give any assistance to their advocates
nor contribute aught to their argument. We have
said that the breeze is stirred by the morning light,
but it no less surely subsides when the full sun has
touched it. And yet the Etesians are called by sailors
sleepy-headed and dainty, for the very reason that, as
my brother Gallic puts it, they cannot get up in the
morning. They begin to show face at the time when
even the most persistent morning breeze has fallen.
This would not occur if the sun reduced the force
of the Etesians as he does that of the morning
breezes. Add also that, if the cause of their rise
was the lengthened space of the day, they would
blow even prior to the solstice when the days are at
their longest, and when the thaw of the snow is at
its height. By the month of July everything is
clear of snow, or, at any rate, very few places are
still covered with it.

1 The meaning is very obscure. The text has been suspected, not
without cause : the words " he still . . . hemisphere " are out of place, to
say the least of it.

CLOUD WINDS 203

XII

THERE are some species of winds which issue i
from clouds that are rent and pour down their
contents. They are called by the Greeks cloud
winds (e'/«>e</>ta<?). Their method of formation, as
I suppose, is this : among the particles given off
by the earth's vapour and carried aloft there is great
inequality and dissimilarity, some being dry and
others moist. When the particles have massed in
one body there is great discord and internal strife,
which probably leads to the forming of certain hollow
clouds with narrow pipe-shaped spaces left between,
much like a flute in shape. In these gaps there 2
is shut up rarefied air, which, being buffeted about
in the confined space and becoming heated, strives to
get more room. It expands and rends its envelope,
breaking forth in wind, which, as a rule, is squally,
since it descends from above and falls on us with
fierce vehemence. It is not diffused, nor does it
come through a wide open space, but it struggles
and opens up its way by main force. As a rule, it 3
is a brief gust. As it bursts through the cloudy
receptacle by which it was confined and overleaps
the battlements, it comes in tumultuous energy,
sometimes not unattended with fire and the sound
of thunder in the heavens. Such winds are much
more violent and of longer duration if they have
taken up in their course other gusts proceeding
from a like cause, and thus several have conspired
to form one. It is just like the flow of torrents of
moderate size, not serious as long as each has its
separate course. But when a number of them have 4

204 PHYSICAL SCIENCE BK. v

combined their streams, they surpass in size regular,
constant rivers. The same thing may probably
happen in squalls ; they are short-lived whenever
they are alone. But when they have joined forces,
and the air expelled from several parts of the sky
at once has all combined in one, both force and
duration are added to them.

XIII

1 So, then, wind results from the breaking up of a
cloud, which breach is effected in several different
ways. The accumulation of air is burst sometimes
by the internal struggle, as it seeks to gain an exit ;
sometimes by the heat produced either simply by
the sun or else by the mutual ramming and friction
of the roaming bodies.

At this point, if you have no objection, one may
raise the question why a whirlwind occurs. In
rivers, when their course has been without any
obstacle for a long distance, the channel is a straight,

2 uniform one. But when they meet some boulder
that juts from the bank, the stream is driven back
and whirls the waters in a circle without a way of
escape, so that in their revolution they are con-
stantly sucked in toward the centre to form a
whirlpool. In like manner the wind pours out in
full force as long as no obstacle stands in the way.
But when it is reflected from some jutting pro-
jection, or is massed in a quarter which com-
bines to form a thin downward channel, then it
revolves upon its own axis, and produces an
eddy similar to that in which, as we have just

3 said, the water revolves. This revolving wind,

WHIRLWIND 205

which always traverses the same spot and is
roused to fury by the mere giddy whirling, is a
whirlwind. If it is a very fierce one, and revolves
longer than ordinary, it ignites and causes what
the Greeks call a fire-wind (TT/O^O-TT^), which is
just a fiery whirlwind. The bursting of such
winds from the clouds produces almost all the
disasters by which herds are carried off and ships
lifted, bodily, right out of the water. Further,
some winds produce different ones by dispersing
the air and driving it before them in other directions
than that toward which they themselves have bent
their course.

It occurs to me at the moment to mention 4
a parallel to wind that may be drawn from drops
of moisture. The single drops may begin to
incline downwards and be on the verge of giving
way, but yet do not manage to fall. When, how-
ever, several have united and the mass has imparted
strength, then they are said to flow and to move.
So, as long as there are slight movements of the
atmosphere disturbed at several points, they do not
produce wind. The latter begins only when all
those movements are united and concentrated in a
single effort. Air differs from wind in degree alone.
A more violent air is a wind ; air in turn is gently
flowing atmosphere.

XIV

LET me now recall a remark that I had made early
in this book, namely, that wind issues from cave or
inner recess of earth. The whole earth is not of
solid compact constitution down to its lowest
foundations, but at many points is hollow,

206 PHYSICAL SCIENCE BK. v

. . . hung over dark retreats.

In some places it contains voids that have no
moisture. Though there is no light there to
show the distinctions in the air, yet I venture to

2 assert that cloud and mist settle in that gloom.
Above ground cloud and mist surely do not
exist because they are seen ; but, rather, they
are seen because they exist. Well, there too rivers
none the less exist that they are not seen. You
must understand that down there rivers flow equal
in size to our own. Some glide gently, others
resound as they tumble down headlong over the
broken ground. So must not you equally allow
that there are some lakes underground and some

3 water in pools without an exit ? This being so, it
is of necessity that the air be charged with moisture,
and that, being charged, it lean in one direction, rais-
ing the wind by its propulsion. We must recognise,
therefore, that from those subterranean clouds blasts
of wind are raised in the dark, what time they have
gathered strength sufficient to remove the obstacles
presented by the earth, or can seize upon some open
path for their exit, and from this cavernous retreat

4 can escape toward the abodes of men. Now it is
obvious that underground there are large quantities
of sulphur and other substances no less inflammable.
When the air in search of a path of escape works its
tortuous way through ground of this nature, it
necessarily kindles fire by the mere friction. By
and by, as the flames spread more widely, any
sluggish air there may be is also rarefied and set in
motion ; a way of escape is sought with great
roaring and violence. This point I will elaborate
in more detail when I go on to treat of earthquakes.

xv A MINING TALE

207

XV

You must now allow me to tell you a little story ! x
Asclepiodotus vouches for the tale. Once on a time
a large party of miners was sent down by Philip
into an old mine, long since abandoned, to ascertain
its prospects and condition, and to see whether
ancient avarice had left anything for posterity to
glean. Down they went with plenty of light to last
for days. In due time, when they were quite tired
by the length of the road, they saw a sight to make
their hair stand on end — huge rivers and vast
reservoirs of sluggish waters, equal in size to any
above ground, not pressed down either with a
weight of earth above, but overarched with an open
vault. I confess I felt lively satisfaction in reading
the story. It showed me that the vices from which 2
our age suffers are not new ; they have been handed
down from ancient days. Nor is it in our age that
avarice has for the first time ransacked the reefs of
soil and stone, searching in the dark for treasure
badly hidden. Those ancestors of ours, whom we
are always vaunting, our declension from whose
standard we constantly bemoan, were also lured
by hope to cut down the mountains and stand
beneath the ruins to -gloat over their filthy lucre.

Before the time of Philip of Macedon there were 3
kings who pursued treasure down to its deepest
lurking-places ; leaving the free air and light of day
behind, they lowered themselves into those caverns,
which no distinction of night from day could reach.
What expectation could lead them on ? What
necessity caused man, whose head points to the

208 PHYSICAL SCIENCE BK. v

stars, to stoop below, burying him in mines and
plunging him in the very bowels of innermost earth
to root up gold ? The quest for the precious bane
4 is no less perilous than its possession. For this he
drove shafts and crawled round his dirty, uncertain
booty, forgetful of day, forgetful of his better
nature, which he abjured. On no dead man does
earth lie so heavily as it lies on those on whom
insistent avarice has cast earth's weight, from whom
it has withdrawn the light of day, whom it has
buried in the depths where that noxious poison
lurks. They had the hardihood to descend to a
region where they found a new order of nature,
forms of overhanging earth and winds raving
through the blind void, where are dread fountains
of waters whose streams none drink, and night
reigns deep and unbroken. And then, after all that
has come and gone, they dread the gods of the
nether world !

XVI

1 BUT to return to the matter in hand ; there are
four winds, divided, according to the cardinal points,
into east, west, south, and north. The rest of the
winds, which are called by different names, are
attached to these :

Eurus has gone toward the dawn and the realms of Nebaioth
And Persia and the peaks that lie beneath the rays of morn.
Evening and the coasts that are warmed by the setting sun
Are close to Zephyrus. Scythia and the Great Bear
Are under the sway of dread Boreas. The land that faces these
Is bathed in unbroken cloud and rainy Auster.

2 Or, if you prefer a briefer enumeration, you may
gather them in one great storm — a physical im-
possibility, by the way :

xvi CLASSIFICATION OF WINDS 209

Eurus and Notus (south) rush together, and with squall upon

squall
Africus (south-west).

And we may add Aquilo (north), which has no place
in the famous battle of the winds to which Virgil
refers. Some make the number of the winds twelve.
They divide the four quarters of heaven into three
parts each, adding two subsidiary winds to each of
the principal ones. On this principle that diligent 3
author, Varro, classifies them. And there is good
ground for it ; the other method, which refers them
to seasonal changes, is very unsatisfactory. For
instance, the sun does not always rise or set at the
same point. He has one place of rising at the
equinox — indeed, the equinox occurs twice a year
— another at the summer, and still another at the
winter, solstice. The wind which sets in from the
direction of sunrise at the equinoxes is with us
called Subsolane (near the sun) ; the Greeks call it
a(/>?7Xt&>T779 (from the sun). From sunrise in winter
Eurus comes, named by our countrymen Vulturnus
(i.e. from Mt. Vultur in the S.E.). Livy also calls it 4
by this name, in connection with that famous battle
of Cannae, which proved so disastrous to Rome.
Hannibal on that occasion managed to get our
army with its face to the rising sun and to the
wind ; by the aid of the wind and the glare that
dazzled the eyes of the enemy he snatched the
victory. Varro likewise uses the same name. But
Eurus is a name now naturalised, and has a place in
our vocabulary that does not suggest any foreign
origin. The wind that is raised by sunrise at the 5
summer solstice was called by the Greeks /cat/eta? ; l
we have no name for it. Sunset at the equinox sends

1 No explanation of this name of the nor'-easter is forthcoming.

P

210 PHYSICAL SCIENCE BK. v

us Favonius, which even people who cannot speak
Greek will tell you is called the Zephyr. Corus,
which is by some called Argestes [from its clear-
ness], comes from the sunset at the summer solstice.
I do not approve of the identification ; Corus is a
vehement wind, rushing in one uniform direc-
tion, while Argestes is, as a rule, a gentle wind,
and blows impartially on travellers coming and
going along the same road (i.e. is constantly
6 shifting). From sunset in midwinter comes the
rushing furious Africus (African wind), named by
the Greeks the Libyan (xfy). In the northern
quarter the highest (i.e. most easterly) is Aquilo,
the central one is Septemtrio, the lowest Thracias,1
for which there is no corresponding word in Latin.
In the southern region there is Euronotus, then
Notus, or in Latin Auster, then Libonotus, which
has no Latin name.

XVII

1 WE Stoics hold that there are twelve winds ; not
that there are everywhere so many (the slope of the
earth \i.e. of the earth's axis] excludes some), but
because there are nowhere more than twelve. We
speak of six cases in the same way, not because
every noun possesses six, but because none has
more than six. Those who assert the number
of the winds to be twelve adopt the principle
that the number must be the same as the divisions
of the heavens. Now the heavens are divided
into five zones passing through the cardinal points

2 of the world. These are the northern, the solstitial,

1 I.e. the Thracian ; Thrace must have been N.W. of the region in which
the name had its origin.

xvii LOCAL WINDS

the equinoctial, the wintry, the one that faces
the northern. A sixth is added in the zone which
separates the upper part of the world from the
lower. As you know, there is always one -half
the world above our head, and one -half beneath
our feet. This line which lies between the visible
and the concealed parts of the sky is called
by the Greeks the Horizon (oplfav = bounding
line) : our school call it the Bounder ; others, the
Bounding [line]. To this must be added the 3
meridian circle, which cuts the .horizon at right
angles. Some of these zones run transversely,
intersecting others. Now there must necessarily
be as many divisions of the heavens as there are
parts. So, then, the horizon or bounding circle
cuts those five zones, of whose position I have
just spoken, making ten parts, five to east and five
to west. The meridian circle which meets the
horizon gives two additional divisions. Thus the 4
air receives its twelve divisions, and yields a like
number of winds.

There are some of the winds that are peculiar to
certain localities ; they do not carry far, but reach only
the immediate vicinity. They do not derive their
impulse from a particular quarter of the world at large.
For example, the wind Atabulus haunts Apulia ; the
lapygian, Calabria ; the Scironian, Athens ; Cataegis,
Pamphylia ; Circius, Gaul. To the last mentioned,
though it shakes their houses, the people are very
grateful, believing they are indebted to it for the
healthiness of their climate. At any rate, the late
Emperor Augustus, when he was staying in Gaul,
erected to it a temple he had vowed. My task
would never be done if I were to attempt to
enumerate the individual winds. There is hardly

212 PHYSICAL SCIENCE BK. v

any district that has not some particular wind that
arises in it and falls not far from it.

XVIII

1 WHEREFORE among the other works of Providence
this one must be regarded as worthy of all admira-
tion. Heaven had many purposes in view in
devising the winds and distributing them through
all the varied quarters of the earth. The first object
was to prevent the atmosphere from becoming
gross ; by their constant tossing the winds were
meant to render it beneficial, a source of life to
those who were to breathe it. In the second place,
they were to supply the earth with rain, and at the

2 same time to restrain excess of rain. This they
accomplish by now gathering, now scattering the
clouds, so that the rainfall should be fairly distributed
over the whole world. The south wind drives it
toward Italy, the north sends it back to Africa.
The Etesian winds will not suffer the clouds to settle
in our quarter ; but yet the whole of India and
Ethiopia are watered with constant rain during the
period of their prevalence. Moreover, crops could
not be gathered in unless the worthless elements
were winnowed by the blast from the good grain
with which it is mixed. The breeze is needed, too,
to rouse the seed and bring to light the latent
fruit, by causing it to burst through its covering,
those wrappings which the farmers call follicles.

3 Furthermore, the wind has established intercom-
munication among all the different nations, and has
united tribes far removed from each other in place.

A great service is this that nature here renders, did

xvm A DOUBTFUL BOON 213

not man's madness turn it to his own injury ! As it
is, the remark may be applied to the winds which
was commonly made regarding Caesar the Elder
(Julius), as recorded by Titus Livius (Livy) ; it was
doubtful whether his birth was a blessing or a
curse to the state. In like manner all the useful
and necessary services performed by the winds can-
not outweigh the devices which man's madness has
through them framed for his own destruction. But 4
they do not cease to be inherently good, even
though, through fault of those who degrade their
use, they are turned to instruments of harm.
Surely Providence and God, the great Disposer of
the world, had a beneficent aim in establishing the
winds, and diffusing them on every side, to wit,
that the atmosphere might be kept in motion
by them, that no part of the world should become
unsightly through inactivity. His object was not
that we might man our fleet with armed soldiers to
seize every quarter of the main, and that we might
go in search of foes either in or beyond the sea.
What frenzy goads us on, and matches us in strife
for our mutual destruction? We spread the sails 5
to the winds to go in quest of war, and we run
risks of sea for the sake of meeting risks of battle !
We tempt the uncertainty of fortune, the force of
tempests that no human effort can overcome, death
without hope of burial. The prize would not be
worth the toil if the voyage conducted us to
peace. As it is, when we have passed so many
hidden rocks and hidden shoals of a treacherous
sea ; when we have escaped the billows that rise
like mountains above us, into which the raging wind
forces all voyagers ; when we have passed through 6
days enveloped in mist, and nights rendered still

214 PHYSICAL SCIENCE BK. v

more awful by cloud and thunder, and by whirlwinds
that rend the frail bark in pieces ; what reward shall
we have for all the toil and anxiety ? What harbour
will give us hospitable shelter, worn out as we are
with so many sufferings ? War, I trow, will meet
us, and an enemy ready prepared on shore and
tribes destined to cruel slaughter, but not without
much damage to the conqueror, and ancient cities
in flames. Why do we press whole nations into
arms ? Why do we enrol armies to marshal

7 their lines amid the billows ? Why do we dis-
quiet the seas ? The land, I suppose, is not wide
enough to compass our death. Fortune deals too
tenderly with us : she has given us too hardy
bodies, too sound health. No ravage of plague
cuts us off: each one may comfortably fill up the
measure of his years and reach the haven of old age.
So let us launch upon the deep and call toward us
the loitering fates. Poor wretches, what is it ye
seek ? Death, which is always too much with us ?
It will attack you, even in your couch ; well, see
that the victims it attacks are innocent of crime. It
will seize you in your house ; be sure it find you
planning no mischief.

s But what can one call it but plain insanity
actually to carry destruction in your train, to
rush in anger against men you never saw, to lay
waste without provocation all that comes in your
path, and, after the fashion of wild beasts, to kill
a man you do not hate ? We are worse than
beasts, for they bite only in retaliation or from
hunger ; but we, utterly lavish of our own and
others' blood, harass the seas by the vessels we
launch, entrust our safety to the waves, and pray for
favouring winds, counting it our good fortune to be

xvni INVASION MADE EASY 215

borne in safety to the wars ! To what lengths have
our crimes hurried us criminals ? It is not enough 9
to vent one's madness within one's own sphere.
Your stupid King of Persia must cross into Greece,
filling it with an army with which he has failed to
conquer it. Your Alexander, leaving behind Bactra
and India, must needs seek to learn what lies
beyond the great sea, and will 'chafe that there is
any point beyond which he cannot go. Crassus in
like manner will fall a prey to the Parthians through
his lust of gold. He will not dread the imprecations
of the tribune who calls him back, nor the storms
of the tedious sea, nor the lightning by Euphrates
that foretold destruction, nor the resistance of heaven
itself. Through the wrath of man and God alike 10
gold shall be sought.

Not without good cause, therefore, it may be
said that nature would have done better by us
had she forbidden the winds to blow at all, had
she checked their roaming abroad in their fury,
and ordered each one to abide in his own land.
If this had served no other end, at any rate the
mischief of each human life would have been
restricted to itself and its own nation. As it is,
the ills of home are too little for us ; we must toil to
share those abroad as well. No land is so far re-
moved from neighbours that it cannot send forth in
some direction its evil propensities. How do I know u
but that some ruler of a great nation meantime con-
cealed from view, swollen by fortune's kindness,
may choose not to confine his arms within the
boundaries of his own realm, but with secret design
may even now be fitting out his fleet against us ?
How can I tell whether this wind or that shall
convey war to me ? It would go far to ensure

216 PHYSICAL SCIENCE BK. v

the peace of the world if the seas could be
shut up.

Still, as I said a little ago, we cannot put the
blame on God, our Author, if we corrupt His

12 blessings and turn them into curses. He gave us
the winds to maintain the equable temperature of
earth and sky, to call forth or to repress the
waters, to nourish the produce of field and tree ;
the crops are brought to maturity, among other
causes, by their mere tossing in the wind, which
attracts the nourishment to the top, and by move-
ment prevents the stagnation of decay. He gave
the winds that we might gain acquaintance with
foreign lands. Man would have been an untutored
creature without much experience of the world if

13 circumscribed by the bounds of his native soil. He
gave the winds that the blessings of each region
might become common to all ; not to convey across
the sea regiments of horse and foot, nor arms for
the destruction of mankind. If we simply estimate
nature's boons by the degraded uses to which they
have been put, there is nothing that we have not
received for our own hurt. Who is aught the better
of the gift of sight ? or of speech ? To whom is
life itself not a torment ? I defy you to find any-
thing of such undoubted utility that it cannot by
misuse be converted into a curse. So it is with the
winds : nature had designed them for a boon ; we

14 have ourselves made them the opposite. They all
lead us to some disaster : one man has not the
same motive as his neighbour for putting to sea, but
none has a good one. Diverse temptations lead us
to essay the way. Above all, we love to go to sea
in order to damage some one. Plato, with whose
testimony I may close, has observed, with great

xvni MISUSE OF DIVINE GIFTS 217

aptness, it is mere trifles that men purchase with
their lives. Yes, my dear Lucilius, if you estimate
aright man's madness, in other words, our own — for
we all wallow in the same herd — you will be
still more amused by the reflection that we amass
for life what in the end wears life out.

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

PHYSICAL SCIENCE

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 8
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 "
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 BK. 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

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 30 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
grandeur1 ; 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 DISCO VER Y GRAD UAL 2 3 1

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 UK. 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.

WATER AS CAUSE OF EARTHQUAKE 233

VII

SOME, who, like Thales, attribute earthquake to the :
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
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
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 ear-th ?

I have myself heard from their own lips the
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
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."
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."

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.

ANAXIMENES affirms that the earth is itself the
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.

24o PHYSICAL SCIENCE BK. vi

it happen that [at times] one of them agitates the
upper air, the other the nether ? 1

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.

xin 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.

242 PHYSICAL SCIENCE

XIV

* 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 i
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.

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 it's right for itself. Air is 3
a thing no man can tame ; nothing will be found
which,

248 PHYSICAL SCIENCE BK. vi

\Vhen 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

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 6
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
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

xxn 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, whom 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

i 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.

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

258 PHYSICAL SCIENCE

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 1 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 1
challenged whether its attack be with vast a 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

xxxn 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
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 habeo—\i'a.\& ;
French is more amenable. "J'ai soixante ans ! Parlez-vous des soixante
ans que vous n'avez plus ? " — NISARD.

BOOK VII

WHICH TREATS OF COMETS

269

I

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

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

271

272 PHYSICAL SCIENCE BK. vn

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

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

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

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

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

1 The common reading, aliis=. others, seems an error for i7//r = them.

i WONDERS OF NATURE— COMETS 273

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

II

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

T

274 PHYSICAL SCIENCE BK. vn

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

Ill

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

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

in CAUSES OF COMETS 275

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

IV

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

276 PHYSICAL SCIENCE BK. vn

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

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

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

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

v METEORS AND COMETS 277

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

VI

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

278 PHYSICAL SCIENCE BK. vn

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

VII

1 A GREAT deal can be urged against this view. First
of all, if wind were responsible, a comet would never
make its appearance without wind. As a matter of
fact, it appears when the air is perfectly still. In
the next place, if it were due to wind, it would
fall with the wind ; and if it began through wind,
would increase with increase of wind, and would be
the brighter the more furious the wind was. This
point, too, has to be added to the foregoing : while
the wind impels many parts of the atmosphere, a
comet appears in one spot. The wind does not
mount up high, but comets are seen higher up than

2 the winds are permitted to go. Epigenes after-
wards goes on to speak of the comets that, he says,
have a more definite resemblance to stars, traversing
an orbit and passing through the zodiacal signs.
He attributes their origin to the same causes as
produce those that he called lower comets, the only
difference being that the earth's exhalations in this
case contain many dry elements, and therefore seek

vii WIND AS CAUSE OF COMETS 279

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

VIII

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

28o PHYSICAL SCIENCE BK. vn

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

IX

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

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

ix INADEQ UACY OF EXPLANA TION 2 8 1

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

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

282 PHYSICAL SCIENCE BK. vn

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

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

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

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

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

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

xi DIFFERENT KINDS OF COMETS 283

XI

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

1 I.e. are cone-shaped.

284 PHYSICAL SCIENCE BK. vn

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

XII

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

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

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

xii CONJUNCTION OF PLANETS AS CAUSE 285

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

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

286 PHYSICAL SCIENCE BK. vn

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

XIII

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

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

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

A SOLID FIRMAMENT' 287

XIV

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

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

2 Or, between the earth and it.

288 PHYSICAL SCIENCE BK. vn

Well, what argument1 then justifies the assertion
that it is not merely the five planets that move,
but that there are many such in many quarters
of the universe ? Or if there is no probable
proof of this, one may rejoin : What is there to
prevent one from saying either that all the stars
4 move or that none of them does ? Besides, your
argument is in no way helped by that crowd of stars
which you assume to be everywhere roaming about !
For the more there are of them, the oftener will
they meet with others ; whereas comets are rare,
and for that reason marvellous. And will not
every age give evidence against you by noting and
recording for the use of posterity the emergence of
such stars ?

XV

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

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

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

xv CONJUNCTION THEORY ERRONEOUS 289

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

XVI

I HAVE refuted the argument ; I must now discredit i
its authors. It requires no great effort to strip
Ephorus of his authority ; he is a mere chronicler.
Some of his class seek to recommend their narrative
by incredible stories, and by their marvels try to
interest the reader, who would probably soon find
some other occupation if he were called on to wade
through their tedious narrative of ordinary events.
Some, again, are too credulous, some too careless,
some are deluded, some delighted, by falsehood.
The former do not shun it, the latter go in quest of
it. The whole clan of them have this in common ; 2
they fancy their work cannot merit approval, and
become popular unless they freely interlard it with
lies. Ephorus is not a person of any scrupulous
honour; he is often duped, often he tries to dupe. For
example, he asserts that the great comet which, by
its rising, sank Helice and Buris, which was carefully
watched by the eyes of the whole world since it
drew issues of great moment in its train, split up
into two stars ; but nobody besides him has re-
corded it. Who, I wonder, could observe the 3
moment at which the comet broke up and was
resolved into two parts ? And if there is any one
who saw it split up into two, how is it that no one
saw it first formed out of the two ? And why did
Ephorus not add the names of the two stars into

u

2 90 PHYSICAL SCIENCE BK. vn

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

XVII

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

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

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

xvn COMET IS NOT PLANET 291

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

XVIII

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

XIX

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

292 PHYSICAL SCIENCE BK. vn

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

XX

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

Long glistening trains of flame behind,

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

2 than usual. That is why it does not remain long,
but glides off once it issues from the cloud, forth-
with perishing. But other fiery appearances remain
for a considerable time, and do not break up until all
the fuel on which they fed has been used up. Here
belong the strange sights recorded by Posidonius
— pillars and shields all ablaze, and other flames
of marvellous strangeness. They would attract no
attention if they ran their course after customary
laws ; but now the sight of them sends all men agape.

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

STOIC VIEW 293

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

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

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

XXI

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

1 I.e. the tail of a comet.

294 PHYSICAL SCIENCE BK. vn

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

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

3 view. No doubt the former found moister elements,
more suitable for its fire, and pursued them ; the latter
in turn chose a richer and more substantial district.
So they descend toward the direction in which they
are invited by their material, and not by a definite
path, which in the two we have seen was different,
since the one moved off toward the right and the
other toward the left. Now all stars1 have their
orbit in one direction, namely, contrary to the motion
of the universe. The latter moves from east to
west, the stars go from west to east. For this
reason they have a double motion, — one, their own
proper motion ; the other, which carries them round
along with the heavens.

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

REFUTATION OF STOICS 295

XXII

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

XXIII

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

296 PHYSICAL SCIENCE BK. vn

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

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

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

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

xxiii UNIQUENESS OF COMETS 297

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

XXIV

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

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

298 PHYSICAL SCIENCE BK. vn

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

XXV

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

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

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

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

xxv SLOW PROGRESS OF KNOWLEDGE 299

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

XXVI

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

300 PHYSICAL SCIENCE BK. vn

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

XXVII

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

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

NATURES RIDDLES

301

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

302 PHYSICAL SCIENCE

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

XXVIII

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

The oil splutters, and rotten fungus covers the wick ;

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

sea — if

the sea

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

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

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

xxvin PROGNOSTICATIONS FROM COMETS 303

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

XXIX

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

3o4 PHYSICAL SCIENCE BK. vn

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

XXX

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

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

xxx REVERENCE AND HUMILITY OF SCIENCE 305

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

XXXI

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

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

X

306 PHYSICAL SCIENCE BK. vn

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

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

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

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

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

xxix PHILOSOPHY UNFASHIONABLE 307

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

XXXII

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

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

308 PHYSICAL SCIENCE BK. vn

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

NOTES ON SENECA'S "QUAESTIONES
NATURALES"

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

THE treatise of which the present volume is a translation
possesses a twofold interest. In the first place, it is prob-
ably the last literary work of a man who filled a large
space in the Roman world of his day. After a varied
career as philosopher, barrister, politician, statesman,
courtier, and man of letters, he at last incurred the
implacable enmity of Nero, to whom he had been tutor.
Having in his youth paid some attention to physical
inquiries, he had then been led to prepare and publish
a book on earthquakes. But in subsequent years the
absorbing cares of State probably left him little leisure to
continue these studies, for which, however, he had retained
his taste. Hence, when in his last days he sought in
retirement to devote himself to philosophical pursuits, he
naturally turned to some of the physical problems that
had interested him in earlier life. The earthquake which
on 5th February A.D. 63 had done much damage to the
towns of Campania, revived his youthful enthusiasm for
the investigation of such phenomena, and may possibly
have suggested to him the preparation of another volume
dealing with this and other scientific matter. We know
at least from the book itself that he wrote a part, if not
the whole, of it after that date (221, 23O),1 and that he
took pains to collect information about the catastrophe.

1 The numbers within parentheses throughout these Notes refer to the
pages of the Translation.

309

3io PHYSICAL SCIENCE

As he was in the habit of sojourning on the shores of
the Bay of Naples, he probably visited the scene of de-
struction himself for the purpose of his book. We learn
from Tacitus that it was immediately after his return
from Campania to his villa near Rome, bringing with him,
we may suppose, his nearly completed manuscript, that
Seneca received the Emperor's order to commit suicide.

In the second place, Seneca's work on Natural
Questions stands out as one of the few treatises on
physical science which have come down to us from anti-
quity. It is interesting alike for the quotations it contains
from the works of previous authors, some of which have
not survived, and for the criticisms and opinions which he
himself expresses on the various subjects of which he
treats. It can hardly, however, be regarded as an original
contribution to science. Its author's life had been spent
in other and widely different pursuits, which led him far
away from scientific inquiry. But as a summary of the
general state of knowledge in his day, made by a man of
strong intellect, who had been trained in the legal and
philosophical schools of the time, and had read widely and
reflected much on these matters, the book may be taken to
afford a fair presentation of the manner in which a number
of questions in astronomy, meteorology, and physical geo-
graphy were regarded by thoughtful minds in the first
century of our era.

In judging of the intrinsic merit of such a work as the
present, the modern reader finds a difficulty in realising
from the broad platform of natural knowledge which, after
the labours of the intervening centuries, has now been
laid, how exceedingly narrow was the circle of ascertained
fact available to the student two thousand years ago. The
spirit of scientific observation and experiment had not then
been developed, yet the familiar phenomena of every-
day life pressed, as they still do, for explanation. Man's
knowledge of nature was then too limited to furnish a
basis for distinguishing what was fact from what was mere
guesswork. In the infancy of our race, as in the childhood
of the individual, the tendency of the human mind is to

NOTES 3II

perceive resemblances rather than differences. Analogies
are readily observed and, in default of knowledge of
the facts involved, are mistaken for identical sequences
of cause and effect Throughout the interpretations of
natural phenomena given by the philosophers of antiquity,
it is remarkable to what a large extent the meaning of
one appearance is explained by comparing it with another
to which in reality it may bear no resemblance. Seneca's
volume abounds in examples of this use of analogy.

The authority of great names exercised a wonderful
fascination on the minds of the early investigators of
nature. Generation after generation of writers were led
to accept with little or no modification the dicta of
eminent philosophers who had preceded them. An ob-
server might sometimes recognise the erroneousness of the
opinion of a predecessor, and yet lack the means of
detecting the falsity of his own, which nevertheless he
propounded with full assurance of its truth. In such
circumstances criticism had no secure foundation, while
credulity, rampant in the world outside, could hardly fail
to show itself in philosophic circles. Even the most
cautious and truth-seeking inquirer might easily and almost
inevitably be led to accept statements which did not seem
to him unreasonable, and which no previous experience of
his own or others warranted him to disbelieve or even to
suspect.

It behoves us, therefore, to be on our guard lest, from
our much higher standard of knowledge, we may be
tempted to look with amused contempt on the puerile
conceptions of nature to be met with in the writings of
the ancients — the grave assertion of absurdities as actual
facts, the inept analogies, the confident explanations which
are no explanations at all, and the complete absence of
any attempt to test by examination or experiment the
validity of statements which with but little trouble could
have been disproved.

These evidences of the exceedingly imperfect knowledge
of his time are fully illustrated in Seneca's chapters. He
quotes some two dozen of previous writers who had dealt

3i2 PHYSICAL SCIENCE

with the same or cognate subjects. It is needless to say
that they were Greeks, no place having yet been found
in Latin literature for treatises on Science. The author
most frequently cited by him is Aristotle, whose Meteoro-
logica he had evidently studied with care. He gives
frequent quotations from that work, but even where he
does not specifically quote, his views generally accord
with those of the great philosopher and naturalist.1 Almost
the only quotations from the works of his own countrymen
are verses from some of the poets, especially from Virgil
and Ovid. It is remarkable that he makes only one
quotation from Lucretius, although he would have found
in that poet's noble work many passages more apposite
to his subject than those which he has taken from the
Aeneid, the Georgics, and the Metamorphoses. We may
suppose that these works were favourites with him, and
that he knew much of them by heart, but that he was less
familiar with the De Rerum Natura.

It is manifest from the present volume that its author,
like Lucretius before him, had a lofty conception of the
dignity and moral influence of the study of nature. This
pursuit seemed to him to raise us above the sordid things
of life and to withdraw the mind from the body — a
dissociation so eminently beneficial to our higher aspira-
tions. He believed that in the study of the hidden
phenomena of the universe a mental alacrity is developed
which will be found to be not without practical utility in
the conduct of affairs that lie nearer the surface (113).

With this clear recognition of the importance of his
theme he resolved in his old age to enter upon a task
which other less worthy pursuits had hindered him from
pursuing. He would now attempt to survey the universe,
unravel its secrets, and give; the results of his studies to
the world ( 1 09). It was not, however, his aim to compose
a systematic treatise on Natural Philosophy, but rather
to take up some special subjects and deal with them in

1 Seneca's indebtedness to Aristotle is emphatically expressed by Barthelemy
Saint- Hilaire in the Dissertation prefixed to his translation of the Meteoro-
logica (Mtttorologie d'Aristote, 1863, pp. Ixix-lxx).

NOTES 313

the light of what had already been written upon them,
and of what his own reflections suggested. His under-
taking assumed the form of a series of epistolary essays
addressed to his friend Lucilius Junior, procurator of
Sicily. The literary shape thus selected allowed the use
of an unconstrained, almost colloquial, style which would
not have been suitable to a more ambitious work.

Had Seneca designed to prepare a formal or methodical
treatise, he would doubtless have planned it to include
the three sections which he regarded as comprising every
inquiry that can arise as to the nature and constitution
of the Universe (Universuin) — celestial, atmospheric, and
terrestrial (Caelestia, Sublimia, Terrena, 51). The world
(Mundus) in his view comprehends all things that come
or can come within our cognisance (54). Instead of
entering upon a full discussion of any one of his three
sections, he selected from them a few topics which had
probably more particularly engaged his attention. Most
of these belong to the second or atmospheric division of
his scheme of arrangement, to which he devotes six of
his seven books, the remaining one being given to the
discussion of some celestial phenomena. Certain subjects
which we should naturally range in the terrestrial series,
such as the source and flow of rivers and the nature and
origin of earthquakes, he explicitly includes among his
atmospheric phenomena (51).

It appears to be probable that Seneca had neither
finished nor revised his manuscript at the time of his
death. Parts of the work are obviously incomplete, though
some of these gaps may be due to defects of transcription
or to the subsequent loss of parts of the text. The
obscurities of language, which are not infrequent, may like-
wise have partly arisen from lack of the author's revision
of his original copy. His discussion of the problem of
the rise of the Nile suddenly breaks off in such an abrupt
manner as to suggest the loss of a portion of the original
volume. One of the most important omissions is the
absence of any account of the phenomena of volcanoes.
The author does indeed refer in several places to this

3i4 PHYSICAL SCIENCE

subject, but with Aetna before him, of which so many
Greek and Latin poets had sung, and which had so often
been referred to in the writings of the philosophers, he
could hardly have meant to offer no commentary on so
notable a feature in the geography and history of his own
country. We know indeed that he was keenly interested
in this mountain, and that he wrote to Lucilius to ascend
the volcano and send him particulars about it. In the
letter conveying this request he alludes to some of the
Roman poets who had sung of its wonders, and urges that
a description of Aetna should form part of a poem on
which his correspondent appears to have been then en-
gaged.1 Another important subject in physical geography
finds no place in Seneca's volume — the Sea. Of the outer
ocean it was not to be expected that he could have had
much to say, but we can hardly suppose that he would have
considered his essay complete without some discussion of
the various phenomena presented by the Mediterranean Sea.
A century before Seneca's prime, the immortal De
Rerum Natura of Lucretius had appeared at Rome, wherein
the origin and constitution of the world were sung with
the intense earnestness, brilliant imagination, and resound-
ing cadence of a great poet and with the grasp and
penetration of a great philosopher. In this splendid work
some of the problems discussed by Seneca were considered,
and explanations were given of them with the usual un-
doubting confidence of olden time. In literary quality the
two writers stand far apart, yet it is not uninteresting to
compare their respective views of nature. The vivid and
often majestic diction of the one is not more diverse from
the somewhat familiar and conversational tone of the other
than are their respective creeds. Lucretius was a con-
vinced and enthusiastic Epicurean, and in accordance with
the teachings of his master denied the existence of any
divine co-operation in the plan and government of the
Universe,

nequaquam nobis divinitus esse paratam
naturam rerum,2

1 Seneca, Epist. Ixxix. 2 De Rerum Natura, v. 198.

NOTES 315

although no writer either of ancient or modern time
has had a more overpowering sense of the beauty,
majesty, and order of this world. It was his earnest
purpose to show men how, by a contemplation of the
face and ordered scheme of nature, they could free them-
selves from the bond of religious superstition and the fear
of death.1

Seneca, on the other hand, held the Stoic belief in an
all-wise and omnipotent Creator. In an eloquent exordium
to his volume, and in a peroration near its end, he affirms
his conviction that this Divine Being is all in all, at once
within and without his works ; He has clothed himself
with creation, but is hidden from our eyes and can be
perceived only by thought (3, 7, 305). Our philosopher
could not conceive of anything more beautiful, more
orderly, and more consistent everywhere in plan than the
world around us. That such a world should have resulted
from the tumult of chaos, by the mere chance collocation
of atoms, appeared to him the madness of vulgar error.
Yet it was only too true, though it might be thought
hardly credible, that even philosophers had been tainted
with this pernicious doctrine. Hence it would be in the
author's judgment a profitable task to inquire into the
truth concerning these matters. To explore this world,
he remarks, is far more than enough for a single lifetime.
Whether what we may be led to believe regarding it shall be
true must be decided by those who may attain the knowledge
of the truth ; we can but examine and conjecture, with no
certain assurance of discovery, yet not without hope (304).
It behoves us to be ever watchful against forming con-
clusions rashly, disrespectfully, or ignorantly, and of being
knowingly untrue. In this quest after knowledge, while
much may be found out which will be of practical useful-

1 rursus in antiquas referuntur religiones
et dominos acres adsciscunt, omnia posse
quos miseri credunt, ignari quid queat esse,
quid nequeat, finita potestas denique cuique
quanam sit ratione atque alte terminus haerens. — Of, cit. v. 86.
hunc igitur terrorem animi tenebrasque necessest
non radii solis neque lucida tela diei
discutiant, sed naturae species ratioque. — i. 146.

3i6 PHYSICAL SCIENCE

ness, we are encouraged to advance, not by any hope of
gain, but by the wonder with which the inquiry fills the
soul. To obtain a knowledge of Nature is the highest
reward to which the mind of man can aspire (230, 304).
Seneca's practical conclusion was thus much the same as
that of Lucretius. He does not, however, attempt in this
volume to enforce it with the solemn earnestness shown
by the poet, though he loses no opportunity of inveighing
against the follies and vices of his time. In discussing
natural phenomena his first desire is to explain them, and
in so doing to animadvert on the explanations of previous
writers, with perhaps a not unnatural wish to show his
own ability as a critic and expositor.

It was in due accordance with the principles of his
school, as well as with his own natural temperament, that
Seneca should continually be led to draw ethical lessons
from the physical phenomena which he discussed. The
interpolation of some of these reflections may occasionally
seem to a modern reader rather irrelevant and far-fetched,
but there can be no question as to the spirit of reverence
with which he approached his subject. Like other philo-
sophers who had preceded him, he maintained this spirit,
while at the same time he had discarded the crowded and
confused polytheism of the prevalent mythology. But he
here keeps this antagonism in due restraint, only occasion-
ally expressing his dissent from the popular creed. He
would not admit that even the old philosophers could
have been so foolish as to credit the gods with some of
the acts which had been popularly attributed to them.
He refused to believe that the guardian and ruler of the
Universe hurled thunderbolts with his own hand. Still
less could he suppose that the gods- had lighter bolts with
which they amused themselves in play. His expression
(fulminibus lusoriis, 91) recalls the bitter irony of Lucretius
and the sarcasm of his question whether, when the gods
aim at lonely places or at the sea, they are only at
practice to strengthen their arms.1 But Seneca held with
Lucretius that in the contemplation of nature we obtain
1 an turn bracchia consuescunt firmantque lacertos ? — vi. 397.

NOTES

3*7

the courage and elevation of mind which fit us for the
trials of life and the coming of death (113).

In the treatment of scientific problems Seneca dis-
plays the same unhesitating assurance of the truth of his
opinions, which was characteristic of the philosophers of
antiquity. These writers had hardly a glimmering concep-
tion of nature's infinite complexity, of the extreme diversity
and intricacy of natural processes, of the unbroken and
endlessly ramifying relations of cause and effect, of the
long and patient investigation by which alone these
relations could be unravelled, and of the caution and
diffidence with which conclusions regarding them should
at least for a time be formulated. Seneca frequently
passes caustic criticisms on the views expressed by his
predecessors. He styles the philosophers, as a body, " a
credulous folk." Some of them he even goes so far as to
accuse of perpetrating deliberate falsehoods (276, 286,
289). Nor does he hesitate to banter his brethren of the
Stoic School, whose "absurdities," as he calls them, he
cannot refrain from quoting.

Yet when his own opinions are examined in the light
of the present day, they are found to be in many cases no
nearer the truth than those which he rejected with con-
tempt. It is, indeed, sometimes difficult to realise the
mental position of a man who could adopt and propound
them. In many cases he accounts for a phenomenon by
the analogy of another to which it has no real affinity,
as where he explains halos by the circular undulations
produced on a surface of water into which a stone is
thrown ( 1 3). He sometimes suggests an experiment to
prove the truth of his assertion, but if he had made the
experiment he would have found how completely it failed
to support him, as, for instance, when he states that a
large pond of water reflects only one image of the sun,
but that, if it is divided into several smaller ponds by the
insertion of partitions, it will show as many images as
there are divisions (18). Striking also and numerous
are the examples of his credulous acceptance of statements
which, had it occurred to him to test them by actual

3i8 PHYSICAL SCIENCE

examination, he could easily have found to be erroneous.
He affirms, for instance, more than once, that while
lightning melts metals, it freezes wine, and he gravely
alleges that when the wine is thawed and imbibed, it
either kills or drives mad those who partake of it (79, 97).
He asserts that the waters of certain rivers have the
power of dyeing whole flocks of sheep, black fleeces being
changed into white, and white into black (137), that some
waters are so dense that even the heaviest objects will
not sink in them (138); that the heat of the sun in the
Nile valley is so great as to melt silver and the joints of
statues (173). When he proceeds to explain the reason
of such abnormalities he expresses no hesitation, but
delivers his opinion with the assurance of a professor
who has obtained the experimental demonstration in
his laboratory.

It is remarkable that although some progress had been
made in astronomy, especially by Greek philosophers,
before the beginning of the Christian era, the conclusions
arrived at by these observers regarding the relations of
the earth to the other heavenly bodies met with but little
acceptance for many centuries, even among reflecting
minds. Lucretius, for example, still believed the earth
to be the centre of the Universe to which all the heavier
materials had converged, while the fire-laden ether escaped
to the outer boundaries of space, sun, moon, and stars
occupying an intermediate place. He did not think that
the sun can be much larger than it looks to be to our
senses, nor was he quite sure whether it is the same sun
which, passing under the earth, reappears in the morning,
or if at the close of each day the sun is extinguished and a
new collection of fires makes a fresh sun in the morning.
He was quite aware of the different views of Chaldaean
sages and astronomers, but in such questions he could see
no reason why one theory should be better than another.1

Seneca, however, had, on the whole, a more advanced
appreciation of the relations of the earth to the heavenly
bodies. He believed the sun to be larger than our globe,

1 De Rer. Nat. v. 564, 650, 680, 727.

NOTES 319

and that a thousand stars might be put together without
equalling his mass (284, 288). He thought the heavens
to be so vast as to afford space for the swiftest of the
planets to rush along with uninterrupted speed during
full thirty years (7). He showed his enlightened outlook
upon astronomical possibilities when he surmised that
comets may have orbits that carry them far beyond the
Zodiac, and when he conjectured that other planets than
those then known remained to be discovered (296-299).
And yet, sharing these more enlarged conceptions, he
clung with curious pertinacity to some of the old childish
faith which was natural in the infancy of mankind.
He knew that some philosophers held that it is the
earth which revolves and not the heavens, and though
he does not deliberately reject this opinion, it is evident
that he still held that the heavens circle round the
earth.1 Again and again he expresses his conviction
that the force which sustains the energy of the sun
and the stars consists of the exhalations that arise from
the surface of the earth. These exhalations, he says,
are the pasturage of the heavenly bodies, the breath of the
world. It would be impossible, he asserts, for the earth
to furnish so ample a store of nourishment to bodies
larger than itself unless it were full of breath which is
passing off from every part of its surface both by day and
night. To the obvious objection that the supply of this
energy would soon become exhausted, he has the reply
that this exhaustion would certainly take place were it
not that the elements are in a condition of continual
transformation, issuing in one form, passing into each
other, and returning to their original positions, thence to
begin their cycle anew (55, 198, 244-5). ^n this uni-
versal transmutation water passes into air, air into water ;
air likewise is changed into fire, fire into air, while earth
is formed from water, and water from earth (120).

In his general conception of the universe, Seneca, as a
Stoic philosopher, recognised a principle of evolution.
He believed that the world embraces in its constitution

1 Seefostea, Notes on Book VII.

320 PHYSICAL SCIENCE

everything that it' is destined to experience from its
beginning to its end. As a human embryo contains the
germ of the future man, so at the first creation of the
universe, sun and moon, the changes of the stars, and the
birth of living things were all embraced. And there were
likewise included the forces whereby the earth is affected,
and which will ultimately lead to the final destruction of
the globe (iSi).1

With regard to the earth itself, whether it is to be
regarded as a soul or as an organised body, Seneca
announced his conviction that it has been constructed
much after the plan of our human bodies. As in these
bodies, veins and arteries are provided for the reception
of blood and breath, so in the earth there are passages,
some for the transport of water, others for the flow of
air (126). He was sure, also, that everything on the
surface of the earth has its counterpart beneath — caves,
mountains, lakes, and rivers.

1 Lucretius, too, had his views on evolution, which are well expressed in
four lines of verse :

mutat enim mundi naturam totius aetas,
ex alioque alius status excipere omnia debet,
nee manet ulla sui similis res : omnia migrant,
omnia commutat natura et vertere cogit.

— De Rer. Nat. v. 828.

BOOK I

IN this part of his Essay the author has grouped together a
variety of phenomena, some of which are meteorological (in the
modern sense of that word), and belong therefore to his class of
Sublimia, while others are astronomical, and would be properly
placed among his Caelestia. They all have reference to light in
some form, and doubtless for that reason were considered as a
series. Seneca, largely swayed by the opinions expressed in
Aristotle's Meteorologies agrees with that philosopher in the
belief that the earth gives forth various kinds of exhalations,
among which some contain the seeds of fire. He thought that
high up in the air, among dry and hot elements, these fires may
be kindled by the sun's rays, and further, that when the atmo-
sphere becomes violently disturbed its friction may give rise to
fires (9, 10, 39).

With these ideas, which he held as established truths, it is
easy to understand that he should have regarded as extremely
foolish the notion that any of the lights which move rapidly
across the sky are of celestial origin. Had such been their
source, he felt sure that by this time there would have been none
left in the firmament ; yet although no night passes when some of
them may not be seen, each star in the sky is found to maintain
its place and its size. Hence he confidently concluded that the
meteors, which are seen at night, and sometimes even by day,
have their birth far below the stars, and are soon extinguished in
their course because they have no solid and abiding resting-place.
Single aerolites and even showers of stones had been recorded
in Roman literature as having fallen from heaven, but it had not
yet occurred to any observer to connect them with the shooting
stars which gleam across the nocturnal sky, and are now recog-
nised to be due to meteorites of different sizes, entering our
atmosphere with planetary velocity, there breaking up with
varying luminosity, and remaining visible for shorter or longer
intervals of time.

The author appears to have regarded as akin to these meteors
321 Y

322 PHYSICAL SCIENCE

the star-like balls of light, which in stormy weather are sometimes
seen on the masts of vessels at sea, and which before his time
had been observed on the points of the spears of an army in the
field. This luminous appearance, regarded by the Romans as a
sign of the friendly presence of Castor and Pollux, is entirely
atmospheric, and has no connection with shooting stars. It is
now known as St. Elmo's Fire, and has been shown to be a gentle
continuous electric discharge from the earth towards a cloud.

Seneca next describes in some detail a series of optical appear-
ances connected with the sun and moon. Until the laws of the
reflection and refraction of light had been discovered, it was
obviously impossible to account for these phenomena. There is,
therefore, much interest in following the lines of thought by which
the old philosophers attempted to explain them. Seneca clearly
perceived that the halos and coronae seen round the sun and
moon in certain states of the atmosphere do not belong to these
luminaries, but to our own air, and may furnish indications of
coming weather. He remarks shrewdly enough that appearances
akin to those seen in the sky may sometimes be observed in the
thick moist air of a bathroom. But when he confidently proceeds
to explain the meteorological phenomena he betakes himself to
analogy, as he is so fond of doing. He remarks that when a
stone is thrown into a pond a succession of circles is produced
on the surface of the water, which continually widen from the
point of impact until they lessen and disappear. In like manner
he believes that when the light of the sun or moon strikes the
cloudy air it produces a similar effect, for as every kind of light
is round in shape, the air is thus driven into a circular form.
His love of analogy generally, as in this instance, leads him far
away from the truth, and prevents him from seeing the palpable
flaws in his reasoning. But the apparent similarity of appearances,
which are in reality entirely dissimilar, contents him with his
explanations.

His discussion of the rainbow (16-33) ^s one °f ^ne m°st
detailed and vivacious in the whole volume. It takes the form
of a sustained argument, in which the author cites various authori-
ties, and replies to objections brought by a supposed opponent
to his thesis, which is that the rainbow is unquestionably an image
of the sun received in a very moist cloud which has the shape
of a round concave mirror (20, 27). He quotes with apparent
approbation the opinion that in a shower of rain each falling drop
is a mirror reflecting an image of the sun, and that when an
observer stands directly between the sun and the shower he sees
the reflections of the countless drops blended into one continuous
semicircle. But as the discussion proceeds the writer denies that the

NOTES 323

cloud consists of separate rain-drops, and he maintains that even
if it did they would not unite to give one unbroken image. In
proof of his contention he urges the fallacious assertion that if a
number of mirrors are joined together and a man is placed before
them, each gives its own reflection, and thus a single man becomes
multiplied into a crowd. If he had ever tried the experiment or
had visited the shop of a mender of mirrors, he would have seen
that the separate pieces, if strictly arranged on the same plane,
reflect a single image. His imaginary antagonist asks for an
explanation of the rainbow-like colours displayed by the spray
from a burst water-pipe, or the splash from an oar, which are, of
course, cases strictly parallel to the falling shower of rain (24).
The resemblance is at once granted, but is explained away on
the ground that the drops fall so quickly that they cannot form
reflections of the sun, and that to produce such reflections the
medium must be at rest. The objector once more strikes in
with a reference to the rainbow colours to be seen in a glass rod
which is placed obliquely in the path of the sun's rays (30).
These prismatic tints, as has long been known, are due to the same
decomposition of white light, as in the rainbow. But Seneca
claims the illustration as furnishing additional arguments in his
favour. He maintains that no colour is really produced in the
rod, but only a false appearance of colour, his idea being appar-
ently that unless the colour is inherent in an object apart from
direct sunlight, it is only apparent and not real. The glass, he
says, tries to reproduce the sun's image, but fails because of its
unsymmetrical form, the reflections being crowded together and
confused into the appearance of a single band of colour. In
regard to the falling drops of rain in a shower he contends that
they receive the colour but not the image of the sun, and he is
led away by the false analogy of the varying tints of a peacock's
neck as the bird tosses its head (25). At one part of the dis-
cussion he affirms that the colours of the rainbow come partly
from the sun and partly from the moist cloud (21). Further on,
however, he agrees that they proceed from the sun, but are only
apparent, for if another cloud comes across the face of the
luminary they at once vanish (29). The greater diameter of the
rainbow compared with that of the sun as seen by us he accounts
for by the analogy of a concave mirror, which greatly enlarges
the objects reflected from it. At the conclusion of the discussion
he repeats his belief that the rainbow and the corona or halo
have no definite material inherent in them, but are like a mirror
which reveals only a deception, the mere phantoms and empty
imitations of real bodies, which certainly do not exist in the
mirror, and therefore cannot come out of it (41).

324 PHYSICAL SCIENCE

In Chapters XVI. and XVII. the author indulges in one of
his favourite moralising episodes, suggested by the topics he has
been discussing in the previous pages. He takes the existence
of reflecting surfaces as his text, and from the calm surface of
still water passes on to artificial mirrors, contrasting the manners
and morals of early mankind, who had only pools and lakes in
which to see their faces, with the luxury and vice of later ages,
when the use of metals led to the invention of metallic mirrors.
In this retrospect, however, he places the discovery of the use
of iron before that of the other metals. The priority of bronze
and the reason for it are accurately stated by Lucretius :

et prior aeris erat quam ferri cognitus usus,
quo facilis magis est natura et copia maior.1

BOOK II

In this division of his work the author discusses various aspects
of the atmosphere and offers an explanation of the phenomena
which he describes. He distinguishes between the very bright
ether on high, and the moist, denser atmosphere which underlies
it, but thinks that they must pass insensibly into each other (66).
The atmosphere he regards as a continuous non-composite body,
capable of great range in tension, and forming the vehicle through
which the exhalations from the earth pass outwards to the sky.
It does not everywhere possess the same qualities. In its lower
parts next the earth it is dense and misty, owing to the terrestrial
exhalations, and is there warmed by the earth's breath, by the
reflection of the sun's rays from the ground, and from the fires,
artificial and subterranean, as well as from the warmth communi-
cated by living animals and plants, for life cannot exist without
heat. The highest portions of the atmosphere are exceedingly
dry, hot, and attenuated, owing to their nearness to the eternal
fires and the heat of the heavenly bodies. The middle parts, on
the contrary, are intermediate in character, but colder than what
lies above and below them (60, 61). It is the lower portions
that are subject to the greatest changes, for they receive the
earthly elements which involve such constant turmoil. The in-
stability of the air arises also in part from the motions of the
earth and from those of the sun, moon, and stars, to which cold,
rain, and other atmospheric disturbances are due (56, 61).

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

1 De Rer. Nat. v. 1287.

NOTES

325

thunder and lightning, divides the phenomena into three kinds
— lightning -flashes, thunderbolts, and thunderings (62). After
citing and commenting on the opinions of various philosophers
he proceeds to give his own views regarding these appearances.
The lightning flash (fulgiiratio) he looks upon as fire widely
spread out, the thunderbolt (fulmen) as fire condensed and
hurled with violence (66). The difference between the two is in
force rather than character; a flash is a bolt without strength
enough to reach the earth, while a thunderbolt is lightning in its
most intense form (69). With regard to the origin of the fire
he points out that fire may be artificially produced in two ways :
either by percussion, as when stones are struck ; or by friction,
as when two bits of wood are rubbed against each other. He
thinks that probably in both of these ways clouds may emit fire,
and that in the violence of storms a source of energy is supplied
whereby the warm or smoky exhalations from the earth may be
kindled and fall with a fierce glow to the earth (70, 101). These
exhalations contain dry and moist bodies, to which heavier ele-
ments may be added. A combination of such materials will
form a thicker and more solid cloud than one of pure air, and
such a cloud may burst with a loud report (78). There can be
no peal of thunder unless the hollow clouds are broken up with
great violence (76). The characteristic path of the thunderbolt
is determined by the oblique current of air in which, while the
natural tendency of the fire is upward, the violence of its dis-
charge presses it downwards and compels it to take up a zig-zag
course. The peculiar ozone odour noticed during thunderstorms,
and long popularly known as the smell of sulphur, is alluded
to by Seneca (69, 97) and by Lucretius.1

The discussion of these subjects leads on to a disquisition on
the portents that may be drawn from different kinds of thunder
and various forms of lightning. Seneca infers from the effects
produced by it that lightning possesses an inherent divine power.
Among these effects he enumerates some in which he seems to
have thoroughly believed, such, for instance, as the smashing of a
wine jar already quoted, and the freezing of the wine for the
space of three days thereafter. He is thus disposed to attach
credit to the opinion that future events are foretold by both

1 Similar views on thunder and lightning are expressed in the De Rerum
Natura :

semina quod nubes ipsas permulta necessust

ignis habere. — vi. 206.

post ubi conminuit vis eius et impetus acer,

turn perterricrepo sonitu dat scissa fragorem. — Ibid. 128.

. . . notaeque gravis halantis sulpuris auras. — Ibid. 221.

326 PHYSICAL SCIENCE

lightning and thunder. Yet he cannot change his Stoic faith
that fate, that is, the necessity for the happening of all things and
all actions, can be set aside by no force, can be altered by no
portents, nor averted by any prayer or sacrifice. Though he
admits that vows and supplications may be useful to the wor-
shippers, he knows that even these also are included in the
decrees of fate.

These reflections lead the philosopher to a characteristic
peroration on the moral lessons to be derived from the subjects
he has been discussing. From the dangers incident to thunder-
storms he passes to the enforcement of the Stoic doctrine that
death must be despised, and everything which leads to death will
then cease to have any terror.

BOOK III

The subjects comprised in this section of the treatise have
reference chiefly to the springs and rivers which appear on the
surface of the earth or flow underneath it. The Book begins
with a preface, which may have been originally designed to stand
at the beginning of the volume. It bears internal evidence of
having probably been written at the time of the author's resolve
to take up the discussion of physical problems, as it speaks of old
age pressing upon him and leaving him but a short while to cover
the immense field which he wished to survey. The years lost
among vain pursuits must be repaired by diligence in the task
now undertaken ; night must be added to day, and every social
or business care which can possibly be set aside must be aban-
doned. The contemplation of the work before him then leads
the philosopher into his moralising mood, wherein he inquires
what should be the principal object of human life, concluding
with the reflection that the best thing a man can set before him-
self, among the ups and downs of this world, is courage to accept
them calmly and to be ready to meet death boldly whenever
summoned. To the acquisition of such a courage a contempla-
tion of nature will greatly conduce.

Seneca begins his discussion of the various forms of water by
grouping them into two chief classes, standing in collected sheets,
as in lakes, or running in channels, as rivers above ground and
springs underneath. After a brief enumeration of various qualities
of water, he inquires whence the vast volume of water comes that
is carried down by rivers to the sea, and how it happens that
neither is the earth sensible of this daily loss, nor does the ocean

NOTES

327

show any perceptible gain. He merely notices the opinion which
some philosophers had expressed that the sea does not get larger
because it restores to the earth as much water as it receives,
allowing its own saline water to sink through endless subterranean
winding passages wherein it is purged of its saltness and rises on
the land as pure fresh water.1 Another view, that most of the water
supplied by rain eventually finds its way into the rivers, is approxi-
mately that at which modern research has arrived, but it meets
with our philosopher's strong opposition. His first objection is
derived from his own observation. He tells us that, as a diligent
digger among his vines, he can confidently affirm that even the
heaviest rain does not penetrate to a depth of more than ten feet
from the surface. What is not absorbed by the upper crust of
the ground runs at once into river channels, and thence into the
sea. He next asks how rain, which immediately flows off the
surface of naked rocks, can possibly be the source of the springs
and rivers that issue from bare crags, or how springs that appear
on the very summit of mountains can be due to rain. Though
he could not but be aware of the close connection everywhere
observable between evaporation, rainfall, and the volume of
springs and rivers, he does not seem to have reflected on its
meaning— how in seasons of drought the surface waters fail first,
how by degrees the springs begin to lessen and even to cease,
how the rivers dwindle until in many cases their beds become
almost or quite dry, and yet how, when welcome rains set in, the
springs and rivers gradually resume the bulk they had before the
dry weather impoverished them. He had made no study of the
way in which rain percolates through the soil, subsoil, and
rocks underneath, though there are places, such as his vineyard
may have been, where,' from some impervious material, only a
feeble or inappreciable flow of moisture descends beyond a few
feet from the surface. Nor was he aware of the innumerable
lines of joint by which the most solid rocks are traversed, and
which serve as passages for the descent and ascent of water.
Had he climbed many mountains, he would have failed to find a
spring on the summit of any one of them, unless there had been
a sufficient area of higher ground at hand to serve for the supply
of the water.

The origin of underground water is regarded by Seneca as

1 This is the view expressed by Lucretius :

. . . ut in mare de terris venit umor aquai,
in terras itidem manare ex aequore salso ;
percolatur enim virus, retroque remanat
materies umoris et ad caput amnibus omnis
confluit, inde super terras redit agmine dulci.

— De Rer. Nat. vi. 633.

328 PHYSICAL SCIENCE

due to three causes. The earth itself contains moisture which it
forces out at the surface ; it includes also air which in the dark-
ness of the subterranean wintry cold is condensed into moisture ;
by the principle of interchangeability, whereby one element passes
into another, the earth in its interior resolves itself into moisture.
If it be urged that the rivers are too vast to draw their supplies
from these sources, the ready answer comes that the internal
reservoir is quite spacious enough for the purpose, and that it
might as well be matter of surprise that, with all the winds that
constantly blow, the supply of air does not fail, or that a single
wave of the sea should be left to follow so many breakers. If
the questioner, still unsatisfied, should demand to know how water
is produced, he is met with the query how air is produced on earth.
There are in nature four elements, and he is not entitled to ask
where one of them comes from. Each is a fourth part of nature,
and it is obvious that what has an element as its source cannot
fail. Hence the philosopher in pronouncing water to be an
element has given it enough, and more than enough, of strength.
In short, rain may give rise to a torrent, but not a river flowing
steadily between its banks. Heavy rains will swell such a river,
but cannot produce it.

Having, as he believed, cleared the ground in this way, Seneca
proceeds to consider the distribution of water within the earth.
He opines that as in our body, so in the earth, there are channels
by which both air and liquids flow. He states his conviction
that the earth contains not only veins of water, but also large
streams, and in a later part of the volume he speaks of both
underground rivers, huge lakes, and a hidden sea from which
rivers at the surface are supplied (154, 233, 235). He is aware
that some of these subterranean reservoirs contain fish, about
which he has some incredible tales to tell. He makes mention
of rivers that sink underground and reappear, as if a matter for
great astonishment. But examples of it may be found in many
limestone districts, where the solution of the rock by underground
water has given rise to tunnels, passages, and caverns into which,
when their roofs give way, surface streams may be engulfed, to
break out again from other openings at lower levels (141). The
author concludes this part of his argument by asking if anybody
is ignorant that there are some standing waters which have no
bottom, whence, he contends, it is shown that this water is the
perpetual source of large rivers.

The various kinds of taste possessed by natural waters are then
discussed, and some marvellous illustrations are given of their
effects. Allusion is made to medicinal springs, to petrifying
waters, to some with extraordinary dyeing properties, and to

NOTES

329

others with neither taste nor smell, but rapidly fatal to the drinker
by immediately hardening and binding the intestines. Refer-
ence is also included to certain kinds of springs, of which the
volcanic tracts of Italy supply good examples. Such were those
which killed visitors who peered down into the caverns where
their waters lurk, and suffocated birds that flew over them.
Doubtless many tales were told of the effects of such emanations
of carbonic acid gas, like that of the Grotto del Cane which, near
Naples, still preserves their classic reputation (134, 261). Again,
the same volcanic districts furnished instances of warm, sometimes
even boiling, springs, and in alluding to them the author quotes
the opinion of Empedocles, who was doubtless familiar with them
in Sicily. To complete his record of marvels, the author cites
some lakes on which islands float to and fro, of which good illus-
trations, due to a matted growth of vegetation, were then well
known in the Vadimonian Lake (Lago di Bassano),1 and he
mentions other lakes in which he had equal faith, with water so
heavy that brickbats would float upon it, and nothing, however
heavy, not even hard solid stones, would go to the bottom.

Seneca is inclined to agree with some philosophers that
certain rivers of peculiar and inexplicable character were created
along with the world, and he specially cites the Danube and
Nile as examples, these vast streams being too remarkable to have
had the same origin as other rivers. Accordingly he reserves
the Nile for consideration in a later part of his volume (166).
There is another kind of water which, with his Stoic brethren,
he places at the beginning of the world — the great ocean and
every sea that flows from it between the lands. Yet he found no
place in any part of the treatise for a discussion of the phenomena
of the ocean.

The Book closes with a vivid description of the probable
catastrophe by which the end of the world will be brought about.
That the present condition of things will be swept away to make
room for another and better race of men he assumes as a matter
of certainty, and he tries to picture by what physical means the
destruction will probably be effected. He is certain that it will
be by no one agency, but that all the energies of the world will
be called forth to compass the destruction of the human race,
nothing being difficult to nature, especially when she is hurrying
towards her end. The picture which is given of the progress of
the great deluge forms by far the most striking piece of writing
in the volume. It ends somewhat inartistically in some gibing
criticism of a quotation from Ovid. But the poetic afflatus had
not been quite quenched. The author immediately returns to
1 Pliny, Hist, Nat. ii. 96. Pliny the Younger, Epist. viii. 20.

330 PHYSICAL SCIENCE

the subject in the succeeding and final chapters, and after enume-
rating the different agencies that may be called out to effect the
destruction of the world, he draws a lurid scene when a single
day will see the burial of the whole human race.1 After this
act of divine wrath has been accomplished, the waters will
disappear below ground, the sea will retire to its own abode, and
on the renovated earth every animal will be created afresh, and a
new race of men will be installed, ignorant of sin and born under
better auspices.

BOOK IV

This section of the treatise begins with a denunciation of
flattery and ends with another against luxury. Neither the
preface nor the concluding chapter have any obvious connection
with the text between them. It is curious to note that while
Seneca here warns his friend Lucilius against flatterers, and in-
culcates how their approaches are to be met, he himself in this
very volume perpetrates four pieces of flattery to the despicable
but all-powerful Nero. He quotes a prosaic line from a poem of
the emperor's, which he characterises as "most elegant" (dis-
ertissime, 25). He refers to Nero as most devoted to truth as
well as to the other virtues (235); he refers to the advent of a
comet which appearing in Nero's reign had redeemed these
heavenly bodies from their evil repute (290), and he describes
that reign as "most joyous " (laetissimus, 294). The old courtier,
so long habituated to the language of flattery, was perhaps hardly
conscious that he was here making use of it, or he may naturally
have reflected that at a time when the emperor had ceased to
bear him any good will, the absence of the customary adulation
might cause as much offence as if a direct insult were intended.

When from his ethical lecture he turns to resume his physical
disquisitions, it is the mysterious Nile to which he devotes atten-
tion. After a brief contradiction of the statement of some
philosophers that the Nile and the Danube are similar in their
characters, he enumerates some of the well-known peculiarities
of the river of Egypt. A problem which greatly exercised the
minds of the philosophers of antiquity, and which has only been
finally solved in our own day, was the cause of the annual rise
of the Nile on which the fertility of Egypt depended. Seneca

1 So Lucretius :

. . . maria ac terras caelumque —
una dies dabit exitio.

— De Rer. Nat. v. 92, 94.

NOTES 331

says with justice that if the point of the river could be ascertained
where the rise begins the question would be settled. He does
not appear to have known much about the river, for he believed
that the water is for the first time collected into a single channel
at Philae. In his account of that place and of the cataract
there (168, 169), he speaks of the river's egress from Ethiopia,
and of deserts which are crossed by the trade route to the Red
Sea. In a subsequent part of the treatise he gives the inter-
esting and important information that he had himself seen and
conversed with two centurions who had been despatched by Nero
to discover the source of the Nile (235). From them he learnt
that they had penetrated far into the heart of Africa, and had
reached a region of illimitable marshes where the river was so
covered and impeded with vegetation that neither on foot nor by
boat could it be ascended. There can be no doubt that these
enterprising explorers had come to the sudd, which in recent
years has been found so serious an impediment to navigation.
They informed Seneca that in the marsh region they had seen
with their own eyes " two rocks from which an enormous body
of the river came out." There are apparently no rocks along
the course of the Nile in the present marsh region, which is a
vast flat, and it is therefore difficult to conjecture to what the
two military surveyors allude. Possibly they saw the mouth of
some affluent of the main stream such as the Khor Adar, or the
sudd may have extended further north than it does now.

Seneca's account of the Nile derived from travellers and
previous writers gives a clear summary of what was then known
about the river, but of more interest is his discussion of the
opinions that had been propounded before his time as to the
cause of the annual rise. He first quotes the view of Anaxagoras,
shared by the Greek tragedians and widely accepted, that this
rise was due to the melting of snow on the uplands of Ethiopia.
This idea he cogently combats by adducing various kinds of
evidence of the great warmth of the climate in those southern
regions. Some of these proofs, indeed, are exaggerations, as where
he affirms that silver is unsoldered or melted. But one of his
proofs, drawn from the habits of the animals of the country, is
worthy of notice. He remarks that no hibernating creature is
found there, and that even in midwinter the serpent is seen above
ground. He argues that in Africa, as in Europe, melting snow
would swell the rivers in spring and early summer, whereas the
Nile flood continues to rise later during four months.

In a subsequent part of this treatise (235) allusion is made to
an explanation which had been given of the rise of the Nile, that
it is due not to the fall of rain from above but to the outflow of

332 PHYSICAL SCIENCE

water from within the earth, and it is in connection with this
opinion that he cites the experience of Nero's two centurions
above referred to, as if he were disposed to believe that what
these explorers saw was really a vast body of water issuing from
underground.

The opinion of Thales is next criticised that the Etesian or
northerly winds drive the waters of the Mediterranean against the
mouths of the Nile and consequently pond back the waters of
the river. This view was of course entirely erroneous, but though
Seneca rejects it, he does not seem to have quite understood it,
for he argues that, coming from the same quarter as the winds,
the Nile water should not have been turbid, but clear and blue,
like that of the sea. In commenting upon the futile support
given by Euthymenes of Marseilles to the idea of Thales, Seneca
throws light on the wide extent to which the coasts of the outer
sea had then been made known by trading vessels.

In rejecting another explanation proposed by Oenopides of
Chios, the author shows that he is aware of the fact that caves
and wells are warm in winter and cool in summer, and that he
has partly divined the reason, when he states that in winter they
are warm since they do not admit the frosty air from without and
in summer they feel cold because the warm air from outside has
not penetrated into their recesses. He returns to this subject in
Book VI. (24 1).1

After mentioning and dismissing a grotesque suggestion of
Diogenes of Apollonia, Seneca suddenly drops the discussion of
the Nile and passes on to the subject of hail. It is obvious that
there is here a serious gap in the text. It is not probable that
he meant to leave off his examination into the probable sources of
the Nile without stating his own view of a matter which had been
so long the subject of wonder and debate. Either, therefore, he
never completed this section of his treatise, or a portion of the
work has been lost.

The remainder of Book IV. is taken up with a desultory
discussion of the subjects of hail and snow, written when the
author must have been in a somewhat frivolous mood. He
begins by telling Lucilius that if he were to assert that hail is
produced as ice is with us, a whole cloud being frozen, he would
be rather audacious. So he will imitate the chroniclers, who
after they have told a great many lies, refuse to be responsible
for some one statement, and refer for its truth to the authorities.

1 The various ancient interpretations of the cause of the Nile's annual rise
are succinctly given by Lucretius (De Rer. Nat. vi. 712-37), but he does
not indicate a preference for any one in particular, though he devotes most
space to the influence of the Etesian winds.

NOTES

333

If, therefore, his friend doubts his word, he will call in Posidonius,
who will tell him that hail is formed from a watery cloud just
turned into liquid. No teacher is needed to explain why pellets
of hail are round, for all drops take that shape. Hail is nothing
else than suspended ice, and snow is suspended hoar-frost. In
this light vein Seneca thinks he has finished the subject and
might dismiss it, but he cannot resist the temptation to continue
the persiflage a little further. He quotes in a bantering style
some of the opinions of his brother Stoics, and after this long
preamble begins an inquiry into *:he distribution of density and
temperature in the atmosphere.

It would have been interesting had he seriously and fully
stated what was known or surmised on this last topic, but he
dismisses it in three short chapters. We learn from these that
he regarded the air to be densest next the earth, and that as all
things retain heat better the denser and more compact they are,
so the air becomes less warm in proportion to its height (iS/j.).1
The opinion of some persons, that the air on mountain summits
ought to be warmer because they are nearer the sun, is sagaciously
controverted, and the insignificance of all inequalities on the
surface of the earth in comparison with the distance from the
earth to the sun is forcibly expressed and illustrated.

The subject of snow and hail is briefly reintroduced at the
end of the Book, probably for the purpose of affording a con-
venient introduction to the invective against luxury which fills
the concluding chapter. The preservation of snow in ice-houses,
and its use in the reparation of jaded appetites by cooling drinks,
calls forth a denunciation of the young rakes of his day, which
closes the discussion.

BOOK V

The movements of the atmosphere form the subject of dis-
cussion in this part of the treatise. In the first chapter the
author seeks for an exact definition of the term " Wind " (ventus\
and ends by adopting one which is obviously inaccurate — " wind
is air flowing in one direction," — for as he afterwards speaks of
whirlwinds he was well aware that the movement may be in every
direction, or vorticose. Dismissing the opinion of Democritus
as to the origin of wind, he states that in his judgment wind may
arise from four different causes. First ; The earth itself breathes
forth a vast amount of air from its interior, where there are large

1 This view hardly agrees with what is expressed in Book II. (60, 61),
but it more accurately expresses the fact.

334 PHYSICAL SCIENCE

rivers and lakes, and where the moist air naturally gives rise to
blasts of wind. Second ; Long-continued evaporation carries the
terrestrial emanations aloft, where the intermingling of the breath
results in wind. Third ; Much more important is the fact that the
air in its very constitution possesses an innate power of motion ;
we cannot imagine that while we ourselves are endowed with a
capacity of movement — and water has this power also — the atmo-
sphere should be left inert and immovable (197). Fourth ; Some-
times the sun is itself the cause of wind, when he loosens and
expands the thick air (198).

In this enumeration allusion is made to one or two features
of natural history which the author appears to accept as fact.
He thinks there must be some vital force in water, otherwise it
could not bring forth animals and plants, as we know it does.
But not only water; fire, too, which devours everything, possesses
this generative capacity, for, unlikely as it might be thought, it
is nevertheless true that fire gives birth to some animals. The
air, too, has some vital energy, as it alternately thickens, con-
tracts, and expands, and rids itself of its impurities. The portion
of it contained within the earth is asserted in a later part of the
volume to be the source of the life of the vegetation at the surface
(244).

The local winds, now known as "land and sea breezes," are
next discussed (198). Instead of the simple explanation which
in our own day has shown these aerial currents to be beautiful
examples of the results of diurnal variations of atmospheric pres-
sure, the ancient theory represented that during the day the
exhalations from the land are borne on high to supply the sun
with nourishment, while at night, as they are not needed for that
purpose, they accumulate until they have filled up a given space
enclosed by mountains. When in such a space there is no more
room, they move towards the quarter to which they can most
easily escape ; hence the wind. It is curious, however, to note
that Seneca only describes the land breeze, which falls away as
the morning advances. He does not specially refer to the
equally characteristic sea breeze, which springs up after the other
dies down, and continues during the day, until in the evening it
is again replaced by the land breeze.

The important Etesian or northerly winds, with all their
important local modifications in the Mediterranean basin, must
have been a subject of constant observation to the Greeks and
Romans. There was a general belief that as these winds reap-
peared regularly in summer, they were in some way connected
with the position of the sun in the firmament. Seneca, after
briefly stating this opinion, dissents from it on the ground that,

NOTES 335

as the sun reduces the strength of the morning or land breeze, it
cannot be through his influence that the Etesian winds then
begin to blow. But he does not explain how he would him-
self account for their occurrence. They are now known to
be further illustrations of the influence of atmospheric pressure.
In summer, when the hot region of the Sahara becomes a vast
area of low pressure, the air streams into it from the north across
the Mediterranean basin.

The account given of cloud winds (203) is an excellent illus-
tration of the utter ignorance of the philosophers of antiquity
of the very rudiments of meteorology, and, at the same time, of
the confidence with which they offered their explanations of the
phenomena of the atmosphere. Even now, after prolonged
investigation, the laws that regulate the production of furious
winds and gusts connected with clouds are far from being fully
understood. The boldest meteorologist of to-day, with all his
detailed experience, would hesitate to express his opinion as dog-
matically as is done in the text. The idea that air accumulating
either above ground or below acquires a vast disruptive force,
obtained wide credence in early times. It was this pent-up
accumulation which was supposed to burst clouds asunder and
produce thunder-storms, while the same energy in caverns under
ground led to earthquakes and the eruptions of volcanoes.

The occurrence of whirlwinds is explained by Seneca from the
analogy of eddies in a river. As the water meets with impedi-
ments in its flow, it is driven back and made to whirl round
before it can continue the onward current, so the wind, as long
as it meets with no obstacle, sweeps on, but when it is thrown
back by any projection in its course, or is collected together into
a highly inclined narrow pipe, it whirls round upon itself like the
eddies of a river. But the cause of the vorticose movement
where there is no visible impediment is, of course, left un-
accounted for.

In the fifteenth chapter of this Book a story is told of Philip
of Macedon, who sent down a party of miners to examine an old
mine. The men brought back to daylight a wonderful tale of
vast caverns with high over-arching roofs, and filled with huge rivers
and vast lakes. If the author's intention was to connect the
spaciousness of these underground chambers with the operations
of ancient miners, he was sadly mistaken, since at no time has
metal-mining led to the excavation of huge caverns ; on the con-
trary, it has always been pursued in narrow shafts and passages.
If the report brought back to the king was veracious, his emis-
saries had only come upon a series of natural grottos and tunnels,
such as are of common occurrence in limestone districts, and

336 PHYSICAL SCIENCE

which have no connection whatever with mining.1 But the
narrative served Seneca's purpose, since it furnished him with the
occasion for a diatribe against the cursed love of gold, which had
apparently been rampant in days long before those of Philip,
and allowed him to supply from his own imagination some addi-
tional lurid horrors of the underground world.

When he gets back to his subject, he enters upon an enumera-
tion of the various winds known to the ancients. He himself
thinks that as the heavens are divided into twelve sections, so
there are twelve distinct winds, not all felt everywhere, but never
exceeding that number. He does not attempt, however, to
account for them. In his reference to the names given to the
various winds, he gives a quotation from Ovid's Metamorphoses,
in which the more conspicuous winds from the different quarters
are mentioned. To this quotation he adds a line from Virgil's
graphic picture of the storm in the first book of the Aeneid, where
Aeolus opens his cave and the south-east, south, and south-west
winds rush out in fury upon the sea. Seneca remarks, in passing,
that such a collocation of winds as Virgil enumerates could
never have happened in a single tempest. The poet, however,
has made no mistake. In a great cyclonic storm the wind
veers round with the compass from south-east by south to south-
west. And even if Virgil had added the north wind, which the
philosopher says he left out, he would only have followed the
invariable course of the winds in the cyclones of the northern
hemisphere, which circle round towards the north as the storm
area is passing eastward.

In conclusion, the author points out the Ideological signifi-
cance of the winds, and is thence led to repeat the time-honoured
reproach against human iniquity which turns the winds from
their beneficent intention to purposes of war.

BOOK VI

This is, perhaps, the most valuable. part of the volume, for it
contains more of the author's own observations than the rest of
the work. It deals more particularly with the great earthquake
of 5th February A.D. 63, which occurred in his own country,
and about which he could collect information at first hand. As
already mentioned, the subject of earthquakes had long fascinated

1 It is possible that these ancient mines were driven in search of metal
seams or veins traversing limestone, like those of lead among the caverned
limestones of Derbyshire.

NOTES

337

him, and he had published, in his youth, a volume about it. The
calamity which brought so much injury to the towns of Campania
was more especially likely to enlist his vivid interest, for the
region that had been convulsed was with him a well-known and
favourite part of Italy, where he often came to spend, on the
shores of the Bay of Naples, such leisure as the life in Rome
allowed him. Besides, it was the native district of Lucilius, to
whom the volume was addressed, and whose town of Pompeii
had suffered from the shock.1 Hence he here plunges at once
into details of the damage caused by this particular earthquake.
As a prelude to his inquiry into the whole question of the origin
of such catastrophes, he indulges in reflections on their appalling
nature. Some of the unfortunate residents in the convulsed dis-
trict had fled from it, vowing never to return. But where, the
writer asks, can they be sure of safety, seeing that no quarter of
the world is exempt from this form of danger ? He urges that it
is at least some consolation to be assured that such calamities
are not the work of angry gods, as was popularly believed, but
are traceable to their own special causes in the processes of
nature (228).

He then considers the various opinions entertained on this
subject by earlier writers, which, on the whole, he regards as crude
and inexact. The cause of earthquakes had been found in water,
fire, air, and the earth itself, or in a combination of several of
these agencies, or even in the co-operation of the whole of them.
As regards the action of water, he dismisses the opinion of
Thales (231), but in the statements of other authors, who maintain
the power of internal water in causing earthquakes, he sees a greater
probability of truth. He fully admits the existence of large rivers
and extensive lakes inside the earth, and that in these dark unin-
habited regions flooded rivers undermining their banks, and a
swollen sea lashed into fury by the subterranean winds, may com-
municate shocks to the surface of the earth (234).

That fire is the origin of earthquakes had been held by various
philosophers, who, however, differed as to the manner in which
the fire acts. Anaxagoras thought it was by explosions caused
from the collision of underground clouds (236) ; others held that
the immense mass of vapour produced by the subterranean
conflagrations as it accumulates may exert such a pressure as to

1 In Seneca's letters, frequent reference is made to his visits to the district.
He seems generally to have taken a villa at Baiae, or some adjacent place on
that western part of the coast. He appears to have been a poor sailor, glad
to make for the nearest landing-place between Baiae and Naples, so as to
escape from the pangs of sea-sickness. On one of his excursions he revisited
Pompeii, and was set into a reverie of his youth there. See his Letters,
49, 5i. 53, 55, 57, 7o, 77-

338 PHYSICAL SCIENCE

disrupt all obstructions ; or when the pressure is less may cause
no more than a heaving of the surface. The idea that the shock
of an earthquake results from the removal of material underneath,
whereby the stability of the overlying portion is undermined, and
a collapse of the ground ensues, was held in various forms.
Some thought that this destruction arose from extensive combus-
tion within the earth. Anaximenes supposed that just as at the
surface, rocks and old buildings yield to the ravages of time and
fall down, so in the interior of the earth similar landslips may
occur and cause shocks to the districts above them (237).1

But the favourite opinion of antiquity regarded earthquakes
as primarily due to the violent commotion of air. Seneca com-
ments on the views of various philosophers, and more especially
Aristotle's, as to the way in which the air acts, and he then pro-
ceeds to deliver his own judgment. He has no doubt that,
though some of the other agencies may co-operate, the chief
motive force in earthquakes is air. By no part of nature, he
affirms, is such violent energy displayed as by air ; it kindles fire,
tosses the surface of the waters into waves, destroys large tracts
of the earth, uplifts new mountains, and raises in the midst of
the sea islands never seen before. Not only does air exist above
ground, but it also fills the hollows and interstices of the interior
of the earth, into which it freely enters from the surface.
Nothing in nature is so restless as air, and the earth cannot but
be affected by the movements of the air included in its inside.
The author agrees with the general opinion that when the air
begins to be agitated in a subterranean cavern which it has filled,
pressed by that which is still entering, it struggles to escape, and,
when it does so, emerges with a violence proportionate to the
narrowness of the passage for its exit. But if unable to make
its way out, it becomes furious, acts like a swollen impetuous
river, and that overthrows everything in its path.2

It is not difficult to realise how this explanation should have
been accepted in antiquity, and should have held its ground
down even into modern times. The violence of the commotions
of the atmosphere was a familiar feature on the surface of the
earth, although its physical causes, variously guessed at, were
utterly unknown. To minds that had no conception of the very

1 The collapse of the roofs or sides of underground caverns may un-
doubtedly be in some instances the cause of local earthquakes. This
origin is enforced by Lucretius :

terra superne tremit magnis concussa ruinis,
subter ubi ingentes speluncas subruit aetas.

— De Rer. Nat. vi. 544.

2 Lucretius gives a picturesque recital of these views (De Rer. Nat.
vi. 535-607).

NOTES 339

rudiments of meteorology, there seemed to be no reason why air
inside the earth should not be affected by as violent hurricanes as
the air outside. And as such hurricanes were the most powerful
natural agencies known, their action was not unreasonably in-
voked to account for the phenomena of earthquakes. Assuming
that the air in a large subterranean cavern would behave as the free
open atmosphere does, the old philosophers did not find them-
selves under the necessity of explaining what was to set the air in
motion within the subterranean recesses and lash it into fury there,
any more than they had to account for tempests above ground.

Obviously, if the air found its way from the outside into the
internal parts of the earth, it must have had equal facilities for
egress. And in the convulsions of an earthquake it might be
supposed to issue with violence through some of the previous
openings or from the rents made at the time. In corroboration
of the truth of the prevalent opinion, it was asserted that after an
earthquake air was found to issue from the ground, but no
account appears to have been preserved of any violent outrush
of air. As a further evidence that it is to the force of air that all
these internal disturbances are due, the author remarks that after
a violent earthquake another shock of equal violence cannot occur,
because the first has opened a passage for the struggling winds.

The progress of investigation has, in modern times, thrown a
flood of light on the phenomena of earthquakes, though there
still remain many problems in the subject which await solution.
It is needless to say that no foundation whatever has been found
for the ancient faith that the air plays the chief part in these
subterranean commotions.

Seneca discusses the nature of earthquake motion. He recog-
nises three kinds of movement — quaking (succusszo), tilting (incli-
natio\ and trembling (vibratid) — and he gives illustrations of the
kind of causes to which they may be referred (252). He believes
that the extent of country convulsed by an earthquake depends
upon the area of the subterranean cavern in which the wind
performs its exploits, and as these internal cavities do not con-
tinuously underlie vast tracts of the earth's surface, no large
spaces of that surface are simultaneously shaken. In his day
there appears to have been no record of a shock affecting the
whole basin of the Mediterranean Sea. He thinks that no earth-
quake ever extends as much as two hundred miles. He cites the
recent calamity in Campania, which did not pass beyond that
district, though marvellous tales about it had spread far and
near, and he gives other examples of the markedly local character
of the phenomena, so far as then known. He affirms that
maritime districts are those most frequently shaken (255, 257),

340 PHYSICAL SCIENCE

in proof of which he gives various instances, including the late
disaster to Pompeii and Herculaneum in a region which had
never been known to be shaken before.

He had received information about the Campanian shock, and
the narrative in which he embodies it has the interest of being
the most detailed account of an earthquake that has come down
to us from antiquity. First of all, as already mentioned, he states
that the movement was confined to the district of Campania, no
mention being made of its having been felt even so near as Rome.
He notices the injury done to Herculaneum and to Naples by
the damage of public and private buildings ; bronze statues were
split open and some people were driven out of their minds. He
records that Campania continued to tremble for some days after
the great shock. He had heard that a flock of six hundred sheep
was said to have been killed near Pompeii. Accepting the report
as true, he sees no reason to suppose that the animals died of
fright, but thinks it not unlikely that they were poisoned by the
ascent of pestilential vapours from the ground. This conjecture of
his receives perhaps some support from the fact that in this volcanic
district, after an eruption of Vesuvius, so much carbonic acid gas
has been said to escape from the ground as to suffocate hundreds
of hares, pheasants, and partridges. But the most vivid experience
of the earthquake which he narrates is that of a grave philosophic
friend who, when in his bath, saw the tiles of the floor separate
from each other, allowing the water to sink through the opened
joints, while the next moment, as the pavement closed again, the
water was forced out all bubbling. A better illustration of the
transit of a wave of shock could not be desired.

Seneca was prepared to believe that great changes had been
wrought by earthquakes on the face of the land. He cites in
support of this view some remarkable examples which had
occurred within the times of human history, such as the sinking
of the towns of Buris and Helice, the disappearance wholly or
partially of the island of Atalanta, and the subsidence of Sidon
(256). He refers also to various striking features of landscape
in different regions which had been popularly assigned to the
work of earthquakes, such as the separation of Ossa and Olympus,
the disruption of Sicily from the Italian shore, and the severance
of Spain from the continent of Africa (263).

That the phenomena of earthquakes are closely connected
with those of volcanoes was the general belief in antiquity, and
continued to be accepted up to the middle of last century. It was
believed in early days that just as the collision of clouds during
storms produces the fire seen in lightning, so during the tempes-
tuous agitation of the air within the earth, such heat is generated

NOTES 341

as to set fire to beds of sulphur or other combustible materials,
and thus that rocks are melted and are forced up to the surface
by the vast energy of the escaping air.1 It is to be regretted that
Seneca has not left an account of his own opinions on this subject,
but from the allusions in the present treatise he may be inferred
to have held the prevalent opinion. He alludes in various
passages to volcanic eruptions that had taken place in his own
time, or not long before, in the Mediterranean basin. An eruption
of Etna is briefly noticed, when the mountain was in violent
eruption, ejecting such a quantity of fine burning sand and dust
as to turn day into night, accompanied with much thunder and
lightning (77). This may have been the eruption alluded to in
similar language by Cicero, who adds that for two days nobody
could see his neighbour.2 Seneca further cites two eruptions in
the Aegean Sea, one of which had taken place in his own time,
when a new island was upraised "by the force of air." He
alludes to Thera and Therasia, and the interesting account
given by Posidonius of the uprise of an island in the same sea,
with attendant circumstances closely resembling those of the
eruptions at Santorin in modern times (73, 252). According to
Asclepiodotus, the fire, after overcoming the resistance of the
thick mass of sea, shot up above sea-level to a height of two
hundred paces.

From a consideration of the causes of earthquakes the author
is led by his accustomed train of thought to draw the ethical
lessons which the subject suggested to him. He repeats his
belief that against the perils of earthquakes, as against all the
other dangers and fears of life, the only assurance is to be
obtained from elevating studies and a contemplation of nature
(265). It matters not when or in what form we shall quit life,
whether from some trifle or from a world-wide catastrophe. To
be happy without fear of anything that may befall us, we must
carry our life in our hands, steeling ourselves against fear, and
prepared even to welcome death as the advent of a friend.

BOOK VII

After a brief introduction, marked by no little elegance and
literary skill, the author introduces the subject of the heavenly

1 This view of the nature of volcanic energy is graphically expressed by
Lucretius (op. cit. vi. 639-702).

2 De Nat. Deor. ii. 38. See also Lucretius (ib. vi. 641), who describes
the more conspicuous features of an eruption, and concludes with the line

ne dubites quin haec animai turbida sit vis (693).

342 PHYSICAL SCIENCE

bodies, and more especially of Comets which he is to discuss in
this Book. He proposes at the outset to endeavour to ascertain
whether the earth stands still while the universe revolves round
it, or if it is the universe that remains at rest while the earth
revolves. But he is led on from one topic to another, without
having arrived at a definite solution of this problem when the
volume comes to an end. From various expressions, however,
it may be inferred that he adhered to the primitive belief that it
is the universe which goes round the earth. Thus in Chapter IX.
he speaks of the movement that drags the universe along and
asks what is swifter than that revolution (281). The heavenly
bodies may not stand or turn aside, they all move onward with
the irrevocable movement of this eternal creation (299).

The opinions of various philosophers on comets are quoted
and criticised. He is especially severe in his comments on
Epigenes, who thought that comets are produced somewhat as
fires are excited by whirlwinds. The Greek threefold classification
of comets is cited, and then Artemidorus comes in for his share
of vituperation ; to disprove his theory of the firmament being a
solid roof to the world would be, in the author's opinion, nothing
but beating the air. Ephorus fares no better, being briefly dis-
missed as often deceiving and often deceived. Apollonius of
Myndus held that many comets are distinct planetary bodies,
which wax and wane like the planets, being brightest when they
are nearest us and growing dimmer as they recede to a greater
distance. But Seneca refuses to admit that they have the
character of true planets ; in his view they are insubstantial
irregular fire (291). But he does not agree with his Stoic
brethren in regarding them as generated in dense air and pursuing
their course according to where they can find fuel to sustain
them (292-4). He conceives that they are not mere sudden
and transient fires, but belong to the eternal works of nature.
They steadily traverse their course, and he can understand that
they may have such wide orbits as to carry them far beyond the
limits of the Zodiac (296). He can see no reason why the five
planets then known should be the only stars that move across
the sky, though others had not yet been discovered. Astronomy,
he remarks, is in its infancy, many mysteries of nature remain
still to be discovered, and the day will come when posterity will
marvel at our ignorance of things which will then appear to be
so evident. Some future observer will demonstrate the paths of
the comets, why they wander so far from the other stars, and
what is their size and constitution. We may be content with
what we have found out, and leave something for posterity to
discover.

NOTES 343

In a tone of sad pessimism he brings his volume to a close.
From a contemplation of the glories that might be achieved by
mankind in searching out the marvels of creation he turns to his
own age and his own country, only to see on every side proofs
of decadence. No one now cared for the pursuit of wisdom.
Philosophy and every liberal study were neglected. The schools
of philosophy were dying. If his countrymen even now would
set themselves with all their energy to the task, if the young
would give their sober attention and the elders would teach them,
they would scarcely succeed in reaching the bottom of the well
in which truth lies. Meanwhile they were searching merely on
the surface of the ground and with but a slack hand.

NOTES BY TRANSLATOR

"AIR"

THE word "air" occurs in the text over 200 times, but not
always as a translation of the same Latin word. With a term so
elastic and so ambiguous it would have been mere pedantry to
attempt a uniform rendering ; and indeed such uniform rendering
would have been more misleading than the course adopted of
rendering according to the context, which the idiom of our language
seemed to demand.

Seneca has two main terms for air — aer and spiritus.
Aer means, generally speaking, either air generically, or the
atmosphere specifically. Spiritus, on the other hand, denotes
air under certain conditions of tension, or strain, or pressure,
when it is capable of exerting force or violence ; to its influence
are attributed many effects due in reality to gases, or other causes.
On p. 52, 1. i, we have the definition "air (spiritus) is the atmo-
sphere (aer) in violent motion"; and on p. 205 the concluding
words of V. xiii. are "air differs from wind in degree alone. A more
violent air is a wind ; air in turn is gently flowing atmosphere,"
where again spiritus is " air " and aer " atmosphere."

Again, in the Aetna, 1. 212, we read, "The winds when
inflated are called spirit ; when in subsidence, air " (Professor
Ellis's translation), where the same terms spiritus and aer are
employed.1

Now if our author had been consistent in the use of the
words, there would have been a strong case for a uniform adop-
tion of " air " and " atmosphere," whenever they occurred. But
numerous passages might be cited to show that he interchanges
the words without apparent motive, just as we do " air " and
"atmosphere." For example, on p. 69, 1. 2, "So fire will pass

1 For a discussion of the meaning of the term spiritus and the parallelisms
in its use by Seneca and the author of the Aetna, see Professor Ellis's edition
of that poem, Prolegomena, pp. xl-xliii.

344

NO TES B Y TRANSLA TOR 345

into air (spiritusY while on p. 71, 1. 9, "the air (aer), which is
interchangeable with fire." Again, on p. 75, 1. 6, "When the
clouds have enclosed air" (spiritus); 1. 26, "atmosphere (aer)
shut up in a hollow cloud." A still more conclusive case,
though the passage is probably in other respects corrupt, occurs
in the last sentence of c. xxix. p. 77, where the first "air" is
sptritus, the second, a mere synonym or variant, is aer.
Cf. p. 187, 1. 27, and the passages cited below from pp. 245,
249, 251, 259, 260.

The translator has little choice. He must follow his author,
and, where the latter makes a distinction, must endeavour to
reproduce it ; otherwise he must, as the author did, observe the
idiom of his own language.

In accordance with this principle aer is usually translated
"atmosphere," and spiritus "air"; but circumstances have
rendered unavoidable a considerable number of exceptions.

The discussion of phenomena in which air plays a part is
contained chiefly in Books II. and VI., and here the distinction
of terms in English has been, so far as practicable, maintained.
In Book II. "air" is a translation of aer about a dozen of
times out of a total of over fifty times that " air " occurs, and in
Book VI. about half a dozen out of a total of nearly seventy.

The following is a list of the places in which " air " translates
aer: —

Book I. throughout.

Book II. pp. 56, 11. 20, 21 ; 57, 11. 17, 22; 58, 1. 3; 59,
1. 26 ; 61, 1. 18 ; 66, 1. 12 ; 71, 1. 9; 72, 1. 22 ; 77, 1. 17 ; 98,
1. 26 ; 101, 1. 28.

Book III. pp. 120, 11. 8, 9 (four times); 121, 11. 11-20
(five times); 123, '1. 28; 129, 1. 3; 134, 11. 26, 28; 135,!. i;
140, 1. 29.

Book IV. pp. 176, 11. 6, 9; 184, 1. 2 ; 1 86, 1. 16.

Book V. pp. 195, 1. 32 ; 196, 1. 7 ; 198, 1. 3 ; 199, 1. 16 ;
202, 1. 6 ; 205, 1. 1 1 ; 206, 1. 3 ; 211, 11. 14, 20.

Book VI. pp. 245, 1. 28; 249, 1. 10 ; 251, 11. 8, 9; 259,
1. 7 ; 260, 11. 26, 29.

Book VII. throughout, with three exceptions, viz. pp. 277,
1. 26 ; 279, 1. 16 ; 281, 1. 4.

In a few cases " air " occurs as a more explicit representation
of a pronoun or an adjective which implies it : in these instances
the context is generally a sufficient guide. Spiritus, too, has
sometimes quite a different rendering, e.g. breath.

On pp. in, 139, 152, "air" is used of a very slight breeze,
the very gentlest breath of wind, and represents aura — a good
illustration of the ambiguity of language.

QUOTATIONS

SENECA is fond of illustrating his subject by passages from the
poets. His favourites are Virgil and Ovid, and only once does
he quote Lucretius, whose work was much more analogous to his
own. The quotations are apparently from memory and betray
occasional inaccuracies, as even the best memories will.
The following is a list of the references : —

Book I. Pref., 8 (p. 6). Virg. Aen. iv. 404.

i. 4 (10). Virg. Aen. v. 528.

iii. 4 (17). Ovid, Metamorp. vi. 65-7.

v. 6 (25). Nero in an unknown poem: one or two
other tags of that versatile tyrant have been
preserved.

vi. i (28). Virg. Georg. i. 380. i.

xi. 2 (35). Virg. Georg. ii. 95. 6.

xiv. 2 (38). Virg. Georg. i. 367. (cf. VII. xx. i).

xvii. 5 (45). Virg. Eclog. ii. 25. 6.
Book II. i. 2 (51). Ovid, Metamorp. i. 55.

xliv. i (91). Ovid, Metamorp. iii. 305-7.

Book III. Pref., 3 (109). Origin unknown: a somewhat similar
sentiment occurs in Aetna, 24.

i. i (114). Ovid, Metamorp. iii. 407.

i. i (114). Virg. Aen. i. 245. 6.

i. i (114). Lucilius, to whom the Q.N. was addressed.
If he was the author of Aetna, as seems not improb-
able, he may have written other poems on Sicilian
topography.

xx. 2 (133). Ovid, Metamorp. xv. 313. 4 (cf. Ibid.
xi. 3 sqq.).

xx. 4 (134). Ovid, Metamorp. xv. 321.

xx. 5 (134). Ovid, Metamorp. xv. 330. i.

xxvi. 3 (142). Ovid, Metamorp. xv. 273-6.

xxvi. 5 (142). Virg. Eclog. x. 4. 5.

xxvii. 12 (147). Ovid, Metamorp. i. 292.
346

QUOTATIONS 347

Book III. xxvii. 12 (147). Ovid, Metamorp. i. 304.

xxvii. 13 (148). Ovid, Metamorp. i. 285. 290.

xxviii. 2 (148). Ovid, Metamorp. i. 272.
Book IV. Pref., 17 (165). Virg. Aen. iv. 373.

Pref., 17 (165). Ovid, Metamorp. i. 241. 2.

ii. 2 (168). Tib. Eleg. I. vii. 26.

iii. 3 (178). Ovid, Ars Amat. i. 475. 6.

iii. 3 (178). Lucret. De Rerum Nat. \. 313.

iv. 2 (179). Virg. Georg. i. 313.
Book V. i. i (193). Virg. Eclog. ii. 26.

xiv. i (206). Ovid, Metamorp. i. 388.

xvi. i (208). Ovid, Metamorp. i. 61-6.

xvi. 2 (209). Virg. Aen. i. 85.
Book VI. ii. i (225). Virg. Aen. ii. 354.

ii. 8 (227). Both quotation and author are doubtful :
another reading attributes the poem to A. Gellius.

xiii. 5 (241). Virg. Aen. vi. 256.

xvii. i (246). Virg. Aen. viii. 728.

xviii. i (247). Virg. Aen. i. 55. 6.

xviii. 3 (248). Virg. Aen. i. 53. 4.

xxii. 3 (253). Virg. Aen. viii. 525.

xxvi. 2 (258). Virg. Aen. iii. 77.

xxix. 3 (262). Virg. Aen. iii. 414-9.
Book VII. x. i (282). Ovid, Metamorp. ii. 71.

xx. i (292). Virg. Georg. \. 367 (cf. I. xiv. 2).

xx. 3 (293). Virg. Aen. ix. 20. i.

xxv. i (298). Virg. Georg. i. 137.

xxviii. i (302). Virg. Georg. i. 392.

xxviii. i (302). Virg. Georg. i. 362.

SOME OF GERCKE'S READINGS

Rendering in the Text.
P- 5> § 7> the Strymon.

8, i, the explanation . . .

Philosophy.

9, 2, such as ... answer

me.
20, 10, an oar . . . water.

37, i, Bothynae (cave-
like . . .).

40, 3, one has seen . . .
( = star-struck).

40, 4, of which more anon.

41, 7, For we judge . . .

foreign body.

II. 51, 2, After "rain, snow,"

56, 2, hold together as one

body.
63, 4, on account of ...

clouds.

348

Translation of Gercke's Text,
the Danube and the Bal-
kans,
my opinion.

which each knows the other
cannot answer.

an oar is covered with
shallow water and pre-
sents a broken appear-
ance.

putei (well-like . . .).

what is struck by them we
call smitten with a flash,
that is, struck without
lightning-bolt, what the
Greeks call oo-TepoTrA^KTo,
( = star-struck).

of which we have spoken.

But we judge that it is the
deceptive appearance of
a mirror, which merely
gives a counterfeit repre-
sentation of a foreign
body.

add " winds, earthquakes,
lightnings."

be subject to tension.

when it has accumulated,
is thrust violently upward
by the massing of the
clouds.

SOME OF GERCKE S READINGS

349

II. 75, 2, and it might . . .
bladder.

95, 2, a third neither.

98, i, (c. Iv.) dry air.
III. 122, 3, when trees are cut

down.
123, i, air is produced.

!32J 3> concealed through-
out, until.

142, 5,youhave yourself . .
Virgil.

149, 4, nor do the waters,
etc.

IV. 1 6 1, 8, the stature . .
arena.

173, 19, nor yet the Cay-

strus . . . deep.

and which might with
greater accuracy be called
harsh, because it emits a
sound like that heard
when a bladder.

a third mixed, a fourth
neither.

air in rapid motion.

when trees are full of sap
and not cut down.

Gercke places c. xiv. im-
mediately after this.

after " throughout " insert
"in others they run above
ground for some dis-
tance."

you, my dear Lucilius, be-
lieve the story as (I said)
in the first part [of my
book], and so does Virgil.

nor do the waters find this
a hard task since the sea
mounts from an elevation
equal to that of the earth
(or land). If the heights
be calculated (or if the
average be taken over
the heights), it will appear
that the surface of the
sea is of uniform level.

the text and meaning are
somewhat conjectural.
Gercke reads "the stature
of an ape matched against
a Thracian in the arena."
For " Apollonius Pycta "
he reads "A. the boxer."

nor the Caystrus which lies
beneath Mount Tmolus
increases in summer, and
yet deep snow lies there
constantly as is natural
in those northern regions.
" Tmolo " is an ingenious
and probable emendation.

35°

PHYSICAL SCIENCE

IV. 1 86, i, no one . . . virtuous.

VI. 232, 2, and, generally speak-
ing ...

244, (c. xv.) to hurry
straight forward.

258, 2, philosophers.

265, 2, (c. xxxi.) soft mate-
rials . . . hard.

VII. 296, 4, every star cannot but
touch . . . zodiac.

by which one may become
only more lettered and
not more virtuous.

if the boats are unduly
sunk, the water uses the
whole force of the bur-
thens it upbears, in order
either to pour over them,
or at any rate to rise to
an unwonted height to
right and left.

to blow where it lists.

scholars, [or philologists].

walls undergo more frequent
but more gentle shocks
than the nature of hard
material allows.

no star can traverse its
course without touching
the zodiac, then I say a
comet may have a differ-
ent kind of orbit and yet
some point in it may co-
incide with the zodiac.

INDEX TO THE "QUAESTIONES
NATURALES"

0 prefixed to a name indicates authorities used by Seneca.

a Academy, 307. School and followers of Plato.
Achaia, 142, 224, 225, 235, 288 (adj.), 303. District in

N.W. of southern part of Greece (Morea).
Actors, regard for, 307.
Adriatic, 153.

Adversity, to be faced with joy, 1 1 1, 112.
Aegean (Sea), 73, 252. Eastern part of the Mediterranean.
Aegium, 257 (2). A leading town in Achaia on the Gulf of

Corinth.

a Aeschylus, 172.
Africa, 117, 212, 236, 263.
Africus (Wind), 210.
Air, tension of, 58 ; wide diffusion of, 60 ; transformed into

water, 119, 121; transformed into fire, 120, 121, 205;

kindled by. friction, 205, 206, 277; kindled within the

earth, 236, 251 ; the cause of earthquakes, 239-48, 251,

254, 255; enters interior of earth, 254, 255.
Albula, 134. Small stream flowing into the Arno near Tibur

(Tivoli) some 1 6 miles E. of Rome.
Alexander (the Great), no, 215, 254 (2).
Alexandria, 273.

Alpheiis, 142 (2), 235. River in Elis in Southern Greece.
Alps, no, 173, 184.

Ambracian (Gulf), 153. On W. of Greece (Gulf of Arta).
Ammon ; see Jupiter.
Amphitheatre, jets of water in, 59.
a Anaxagoras, 63, 68, 172, 178, 236, 276. Celebrated Ionian

philosopher, 500-428 B.C.

a Anaximander, 67. Ionian philosopher, 610-547 B.C.
a Anaximenes, 67, 237. Ionian philosopher about 500 B.C.

352 PHYSICAL SCIENCE

Animals, blind in subterranean waters, 129.

Animals, new forms of, discovered in Seneca's time, 305 ;

many still to be found out, 305.
Antiochus, 288. King of Syria, 137-128 B.C.
Antony (Mark), 172.
Ants, mankind compared to, 6.
Apennines, 184.

Apollonia, 12, 68, 176. Town in Illyria.
a Apollonius (of Myndus), 274, 290, 300. Said to have

flourished about the time of Alexander the Great

(330 B.C.). There may be some confusion in the text

between him and the celebrated Pythagorean philosopher,

A. of Tyana, who was born shortly before the Christian

era.
Apollonius Pycta (or pyctes = the boxer), 1 6 1 . Unknown

otherwise ; apparently a gladiator.
Apulia, 211. District in S.E. of Italy.
Aquarius (sign of the Zodiac), 301.
Aquilo (Wind), 209.

a Aratus, 37. Of Cilicia, astronomical poet, flourished 270 B.C.
Araxes, 246. River in Armenia (Aras).
Arcadia, 122, 137. District in centre of Southern Greece.
a Archelaus, 239. Philosopher, flourished about 450 B.C.

Pupil and partly disciple of Anaxagoras.
Arethusa, 142 (2), 235. Celebrated fountain in Syracuse in

Sicily.

Argestes (Wind), 210.

Argolic, 142. Argolis is a district in N.E. of Southern Greece.
a Aristotle, 8, 9, 10, 19 (2), 33, 63, 240, 242, 276, 277, 302 (2),

3°3 (2)> 3°4- See Introduction.
a Artemidorus (of Parium), 22, 286 (2), 287. Not otherwise

known.

a Asclepiodotus, 74, 77, 207, 246, 253. Not otherwise known.
Asia, 224, 233. Province on the W. coast of Asia Minor, or

generic name for area E. and N.E. of Europe.
Astronomy (Caelestid), scope of, 51; of Egyptians, 274; of

Chaldaeans, 275; of Greeks, 298.
Atabulus (Wind), 211.
Atalanta, 256. Small island between Euboea and mainland

of Greece. The channel now bears the name Talanta,

which is likewise that of a neighbouring town.
Athens, 211.

a Attalus, 94, 95. Stoic philosopher, one of Seneca's teachers.
Attalus, 288. King of Pergamus, 241-197 B.C.
Atlantic Ocean, 174, 175 (2).

INDEX 353

Atlantic Ocean, growth of trade to ports on shores of, 175.

Atmosphere, friction of, produces fires, 9, 39 ; upper portion
dry and hot, 39, 60, 65, 78 ; possesses unity or con-
tinuity, 52, 57 ; place of, in universe, 54 ; earthy elements
of, 56, 60 ; tension of, 56 ; lowest portion dense and
dark, 60, 184; and warmer than the rest, 183; distribu-
tion of temperature in, 60, 184; causes of movements
of, 6 1 ; relation of, to the ether, 65, 66; adapted to
transmit sound, 77; rarefied, kindles fire, 100, 205; by
violent movement sets itself on fire, 102; proof that it
is never absolutely motionless, 193 ; possesses a native
capacity of movement, 197.

Atoms, the world a fortuitous concourse of, 7.

Augury, kinds of, 79, 80, 82.

Augustus, 9, 12, 42, 211, 290.

Auster (Wind), 210.

a Authorities (various, not specified by name, but spoken of as
"certain," "some," etc.), 1 8, 31, 35, 57, 63, 67, 73, 75,
93, 101, no, 116, 118, 119, 122, 135, 148 (2), 150,
182, 184, 186, 230, 233, 236, 238, 239, 242, 243, 244,
283.

Avarice, denounced, 207.

Bactra, 215. In Central Asia (Balkh).
a Balbillus, 171. Governor of Egypt in Nero's reign, 53.

Balkan Mountains ; see Haemus.

Baths, heating of water of, 136; effect of Campanian earth-
quake on tiled floor of, 264.

Bathyllus, 307. A native of Alexandria, freedman at Rome
during reign of Augustus; perfected a pantomimic or
ballet dance.

Bear (Great), 208.

Belus, 151. Babylonian deity.
0 Berosus, 151. Priest of Belus, about 250 B.C.

Black Sea ; see Pontus.

Boeotia, 137. District in Central Greece.

Boreas (Wind), 208.

Bothynae (meteors), 37.

Breezes, morning, 195, 198.

Buns ; see Helice.

0 Caecina, 86, 94, 95, 100. A friend and correspondent of

Cicero, about 48 B.C.
Caesar (Julius), 166, 213, 290.
Caius (Emperor Caligula), 163, 164.

2 A

354 PHYSICAL SCIENCE

Calabria, 211. District in extreme S.E. of Italy.
a Callimachus, 172. Grammarian and poet; chief librarian

of Alexandrine library, 260-240 B.C.
a Callisthenes, 254 (6), 258, 276, 277. Relative and pupil of

Aristotle, friend and victim of Alexander the Great.
Cambyses, 78. King of Persia, 529-522 B.C.
Campania, 221 (2), 224 (2), 225, 239, 257, 259 (adj.), 264,

265. District in Italy containing Capua, Naples, etc.
Cancer (sign of the Zodiac), 151.
Cannae, 209. In Apulia.
Cannon, ancient types of, 67.
Capitol, 91.

Cappadocia, 138. Centre of Asia Minor.
Capricorn (sign of the Zodiac), 151.
Caria, 132, 142 (adj.). S.W. of Asia Minor.
Carthage, no, 166.
Caspian, 153.
Cassander, 122. Son of Antipater, regent of Macedonia ;

eventually king of Macedonia; died 297 B.C.
Castor and Pollux, n. Constellation and sign of the Zodiac

(Gemini).

Cataegis (Wind), 211.
Cataracts (Nile), 168.
Caucasus, 173.
Caves with noxious air, 134; felt to be warmer in winter than

in summer, 176, 241.
Caystrus (or Cayster), 173. River in W. of Asia Minor flowing

into the sea near Ephesus.
Chalcis, 246, 257. Chief town of Euboea on Strait at

narrowest point.
* Chaldaeans, 81, 275 (3), 302.

a Charimander (or Charmander), 276. Otherwise unknown.
Charms, laws against, 182.

Charybdis, 153. Whirlpool in Strait of Messina.
Chasmata (meteors), 38.
Chersonese ( = peninsula), 142. Carian or Rhodian on S.W.

of Asia Minor.

Chios, 175. Island and town (Scio) off coast of Asia Minor.
a Cicero, 100.

Ciconians, 133. Tribe in Thrace.
Circius (Wind), 211.
Claudius (Emperor), 290, 294, 304.
Cleonae, 181, 182. Town in Argolis.
Cleopatra, 172 (2). Antony's celebrated partner.
a Clidemus, 99. A philosopher anterior in date to Aristotle.

INDEX 355

Clouds, as sources of lightning and thunder, 10, 62, 63, 64,
75, 203; invisible when we are within them, 24; com-
position of, 24; compression of, causes thunder, 67;
produce fire, 70, 74, 100; must be burst before they
emit sound, 76, 98 ; not necessarily connected with wind,
195; as sources of wind, 203, 204.

Cloud- winds, 203.

Colours (in rainbow), origin of, 21, 25, 30, 31.

Comets, infrequency of, 272, 288, 301 ; what are they \ 272 y
points of resemblance of, to planets, 273; resemblance
to meteors, 275, 276; classes of, 276, 296; not due to
wind, 278, 279-282 ; curved path of, 279 ; long visibility
of, 282 ; distribution and shape of, 283 ; Greek classifica-
tion of,, 2^3; different from the planets, 284; examples
of, .288, 290; vast orbits of, 290, 297, 302; vary in
apparent size as they advance or retreat, 291 ; trans-
parency of, 291, 300; Stoic opinions regarding, 291-294;
directions of, 294, 303, 304 ; Seneca's opinion, 295, 305;
form of, 300 ; portents from, 302.

a Conon, 274. Astronomer; born at Samos ; lived at Alex-
andria about 250 B.C. Said to have been a friend of
Archimedes.

Constellations, 301.

Contentment, duty of, 112.

Continuity or unity, defined, 53.

Corus (Wind), 210.

Corycian (Mt), 122. The district round Corycus in Cilicia
was famous for saffron.

Crassus, 215. Celebrated Roman, slain in battle in Mesopo-
tamia, 53. B.C.

Crete, 123, 153 (adj.).

Crispus Passienus, 160. Stepfather of Nero. Consul in 42.

Crocodiles and dolphins, fight between, 171 ; chase of, 172.

Cutiliae, 139 (2). In the Sabine country, N.E. of Rome.

Cyclades, 147. Group of islands in Grecian Archipelago.

Cyclopes, 91. Jove's fabled armourers with workshops beneath
Etna, Stromboli, etc.

Cyprus, 259.

Dacian, 5.

Danube, as a political boundary, 5, 233 ; alleged remarkable

character of, 135; floods of, 146; contrasted with the

Nile, 1 66; not swollen in winter, 173.
Darius, 254. King of Persia, 521-485 B.C.
Death, to be faced without fear, 103, 223, 226, 265-268 ;

356 PHYSICAL SCIENCE

equalises mankind, 223 ; the introduction to a better

place than earth, 267.
Delos, 258, 259. Perhaps the most famous of "the isles of

Greece."

Deluge, that is to destroy the earth, 143.

a Demetrius, 161. 'Cynic philosopher, contemporary of Seneca.
Demetrius (father and son), 288. Kings of Syria between

162 and 125 B.C.
a Democritus, 183 (2), 194, 249, 250, 276. The optimist or

" laughing philosopher " of Abdera in Thrace ; said to

have lived 460-361 B.C.
"Diogenes (of Apollonia in Crete), 68, 176, 177. Pupil of

Anaximenes, lived in fifth century B.C.
Dnieper (Borysthenes), 174.
Dog-star, 202.

Dolphins and crocodiles, fight between, 171.
Doris, translated " sea nymph " in the quotation from Virgil,

142.

Dowsers, 127.

Drops, globular form of, 178.
Drunkenness, 134, 188.

Earth, material of, formed from water, 120, 121.

Earth as a whole, place of the, in universe, 5 5 ; formed after
the plan of our bodies, 126, 151, 242, 255; final de-
struction of, 143 ; itself the cause of earthquakes, 237 ;
whether it or the universe revolves, 273.

Earth's interior, water supply in, 119, 206, 233, 234; cold
temperature of, 119, 121; like surface above ground,
128, 206; blind animals in waters of, 129; origin of
wind within, 206, 239, 243, 244, 254; landslips in, 238,
249, 251; store of vital air in, 244, 245.

Earthquakes, causes of, 51, 229, 230, 236, 249; effects of,
121, 221, 229, 257, 259, 262, 263; Campanian (of A.D.
63), 221, 257, 259, 262, 264 ; influence of, on the human
mind, 222, 262 ; widespread destruction produced by,
223 ; not the work of angry gods, 228 ; Seneca's youth-
ful work on, 230; water as the origin of, 231; fire as
the origin of, 236, 238; air as the origin of, 239-248,
251, 255, 256, 264; mixed sources of, 249; varieties of
movement in (tnclinatio, sucatssio, tremor), 252 ; most
frequent near the sea, 255 ; cause of local extent of, 257;
features of the Campanian, 259-264; the first shock of,
the most violent, 264.

Eclipses, 35, 274, 284, 293.

INDEX

357

Egypt, 6, 167-177 (passim}; great heat in, 173 ; said not to

be visited by earthquakes, 258.

a Egyptians, ideas of, as to the elements, 125 ; astronomy of, 274.
Elements, interchangeability of, 120, 121, 245; four in

number, 123; contrariety of, 301.
Eleusis, 306. In Attica, N.W. of Athens about 12 miles;

scene of the great Eleusinian mysteries.
Elis, 114, 257. District in S.W. of Southern Greece.
Emanations, terrestrial, feed the sun and stars, 55, 198, 244;
cause thunder, lightning, and commotion of the air, 63,
2 75 > dry and moist, 63, 78.
a Empedocles, 136 (2). Philosopher of Agrigentum in Sicily,

flourished about 444 B.C.
a Ephorus, 289 (3). Greek historian of some repute about

340 B.C.

a Epicurus, 250. Born 342, died 270 B.C.
a Epigenes, 274, 275, 276, 277, 278, 279, 280 (2), 283. A

Greek astronomer of Byzantium of uncertain date.
Erasmus, 142. River of Argolis.
Etesian (Winds), 174 (4), 175, 201 (4), 202 (4), 212.
Ether, characters of the, 65 ; descent of force from the, 68.
Ethiopia, 6, 117, 167, 168, 172, 173, 212, 235. Term was
applied very loosely to all the hinterland of Africa, only
the Mediterranean coast and a portion of the Nile basin
being known to the Greeks.
Etna, 77.
n Etruscans (or Tuscans), 79, 88, 92, 95 (sing.). Etruria lay

immediately N. of the Tiber.
a Eudoxus, 274. Astronomer of Cnidus in Caria, pupil of

Plato, flourished about 366 B.C.
Euphrates, 5, 215.
* Euripides, 173.
Euronotus (Wind), 210.
Europe, 173 (adj.), 233.
Eurus (Wind), 208, 209.
« Euthymenes (of Marseilles), 174, 175 (2)- Geographer,

probably about 150 B.C.
Evaporation from the earth, 198, 200, 240.
Expiation, the reason for, 83, 84.
Eyesight swifter than hearing, 64.

a Fabianus (Papirius), 144. Distinguished Stoic, one of

Seneca's teachers.

Falernian (wine), 35. District famous for wine in N. of
Campania.

358 PHYSICAL SCIENCE

Fate, unalterable, 83 ; nature of, 84, 91 ; uncertainty of
visitations of, 225.

Favonius (Wind), 210.

Fear, how to be combated, 103, 225, 229, 265, 266, 267;
arises from ignorance, 229 ; leads to loss of reason, 262.

Fidus Annaeus, 161. Apparently a gladiator of gigantic
stature.

Fire, kindled in atmosphere, 39, 62, 64, 70, 100, 102; passes
into air, 120 ; artificial modes of producing, by percussion
or friction, 70; naturally rises, 71, 102 ; endowed with the
power of producing some animals, 197 ; as the cause of
earthquakes, 236, 238 ; produced in the earth's interior,
251 ; kindled by air, 251.

Fires, celestial, 8, 39, 294, 295, 296.

Fish in underground waters, 129, 132.

Flattery, counsel against, 159.

Floods, the earth to be finally destroyed by, 143, 144.

Fortune, vicissitudes of, in.

Fountains, discharges from, 142.

Fucinus, 1 1 6. Large lake in Sabine country E. of Rome.

Gaetulicus, 163. Cn. Cornelius Lentulus G., put to death

by Caligula 39.
Galatia, 138.
Gallic, 6.

Gallio, 1 6 1, 202. See Introduction.
Gaul, 117, 122 (pi.), 211.
Geography (Terrena), scope of, 51, 52.
Germanicus, 9. Nero Claudius Drusus, brother of the

Emperor Tiberius, died 10 B.C.
Germans, 233.
Germany, 5, 117, 166.
Gibraltar, 175.
Glass, globe of, filled with water magnifies objects, 29 ; cause

of iridescence in, 30.
God, nature of, 3, 4, 7, 8, 91, 305; sends portents, 80;

unchangeable, 84 ; to Him everything is present, 84 ;

His design in creating the winds, 213, 216.
Gods, dread of infernal, 208 ; do not disturb heaven or earth,

228 ; not to be feared, 266.
Gold, lust for, denounced, 5, 208, 215
Greece, 215, 274(2), 298.
Greek, 58, 95, 210, 255.
0 Greeks, 12, 13, 15, 34, 39, 40, 140, 169, 198, 203, 205,

209(2), 210, 211, 240, 255, 283.

INDEX 359

Gusts of wind, origin of, 203.

Gylippus, 12. Spartan commander against Athenians at
Syracuse, 414 B.C.

Haemus (Balkan Mountains), 122.

Hail, 177, 181 ; falls more in summer than winter, 179;

prognostications of, 181.

Halos (crowns), round sun and moon, 12, 14, 34, 41.
Hannibal, no, 209. Famous Carthaginian general in Second

Punic War, 219-201 B.C.
Happiness, how to be gained, 5, 266.
Heavenly bodies, influence of, on rivers, 141 ; on weather, 275 ;

apparent retrogression of some, 299.
Heavens, extent of the, 7 ; contemplation of the starry, 271 ;

divisions of the, 210; supposed by Artemidorus to be a

solid vault, 286.
Helice and Buris (or Bura), 254, 257, 259, 267, 276,

277, 289. Towns in Achaia swallowed by earthquake

373 B.C
Heracleotic (mouth of the Nile), 171. Most westerly and

largest, not far from Alexandria.
a Heraclitus, 100. Ancient representative of pessimism, "the

weeping philosopher," of Ephesus, toward end of

sixth century B.C.
Herculaneum, 221 (2), 259.
a Homer, 258.
Horizon, 211.
Hostius Quadra, 42. Unknown save for Seneca's unfortunate

mention of him.
Hydissus, 132. Orthography of this Carian town is uncertain ;

Gercke reads Idumus.
Hydraulic organs, 56.

lapygian (Wind), 211.

Ice, 140.

India, 7, 212, 215.

Intermittent action, 128.

Iron, discovery of, 45 ; money made of, 46.

Islands, floating, 139.

Ister (or Hister), a name of the Danube, which see.

Italy, no, 117, 133, 212, 261, 262 (adj.), 263.

Junior; see Lucilius, 168.

Jupiter (Jove), temple of, in African desert (Ammon), 78;

360 PHYSICAL SCIENCE

his thunderbolts, 88, 89, 91, 92; affords lessons to
earthly rulers, 90 ; other names for, 91, 92.
Jupiter, the planet, 284, 299.

Lacedaemonians, 189. Lacedaemon, or Sparta, was in
Laconia, the district in the S.E. of Southern Greece.

Ladon, 257. River in Arcadia, tributary of Alpheus.

Laelius, 268. Friend of the younger Scipio Africanus, consul
140 B.C. Chief interlocutor in Cicero's Dialogue on
Friendship.

Lakes, with dense water, 138, 139; underground, 154; wide
extent of some, 233.

Land and sea breezes, 198.

Landslips, 238, 249, 251 ; effects of, 253.

Latin, 210 (2).

Leo (sign of the Zodiac), 301.

Lepidus, 166 (3). Formed with Augustus and Antony the
Second Triumvirate after Caesar's assassination in
44 B.C.

Libonotus (Wind), 210.

Libyan (Wind), 210.

Life, the proper conduct in, 112, 159, 266; uncertainty of,
226 ; to be carried in our hand if we desire to live happy
and without fear, 266.

Lightning, 62, 66, 69, 86, 87, 100; effects of, 78, 87, 88,
96; portents indicated by, 79, 81, 82, 86, 92, 94, 95,
215; possible pestilential power in, 97; cause of zigzag
course of, 102 ; moral lessons to be derived from a
consideration of, 104; safe retreats from, 223; blinding
effects of, 292 ; connected with the planets, 275.
a Livy (Titus Livius), 209, 213. Roman historian, 59 8.0-17.

Lower Sea ; see Propontis.

Lucilius Junior, i, 103, 109, 114, 142, 159(2), 161, 162, 163,
217, 221, 265, 267, 268. See Introduction.

Luxury, introduction of, 45, 46; growth of, 47, 188; illustra-
tions of, 129, 187; denunciation of, 130, 187, 306.

Lycia, 140. District S.W. of Asia Minor.

Lycus, 142. River, probably of Phrygia in Asia Minor,
flowing into the Maeander.

Lydia, 139. District in W. of Asia Minor.

Lyncestis, 134.

Macedonia, 138, 207, 224, 303.
Magnesia, 122. Town of Lydia.
Mankind, compared to ants, 6 ; early ages of, 45, 46 ; final

INDEX 361

destruction of, 147, 152; re-creation of, after the deluge,

155 ; world not made only for, 305.
Marmora or Marmara (Sea of) ; see Propontis.
Mars, the planet, 10, 275, 284.
Marseilles, 174.

Marshes, 233 ; of the Nile, 236.
Magalenopolis (or Megalepolis or Megalopolis), 257. Town in

Arcadia.

Melas, 137. River of Boeotia in Central Greece.
Memphis, 170. Great Egyptian city a little above Cairo.
Menander, 165. Athenian comic poet, 342-291 B.C.
Mercury, the planet, 284.
Messalina, 163. Third wife of Emperor Claudius ; put to

death by Narcissus, 48.
Messana (Messina), 142.
Metalliferous veins, 126.
Metals, melted by lightning, 78, 96 ; denunciation of the

search for the precious, 207, 215.
Meteorology (Sublimia)^ scope of, 51.
Meteors, 8-n, 37, 38, 40, 275, 276, 292, 293, 296.
Metrodorus (of Chios), 248 (2). Philosopher who flourished

about 330 B.C. "Sceptic." Disciple of Democritus, perhaps.
Milky Way, 289.

Mind, the human, its nature and seat unknown, 297.
Mines, water in, 154 ; ancient, explored by Philip of Macedon,

207.

Mirrors, 22, 23, 24, 27, 41, 42, 44, 45, 47.
Mock-suns, 35.

Moon, eclipse of, 298 ; varying colour of, 300.
Moral reflections, Seneca's, 1-8, 42, 44-47, 102-105, 109-

114, 130-132, 143-156, 159-166, 186-190, 207, 213-

217, 222-229, 254. 265-268.
Mountains, insignificance of height of, compared with the

whole mass of the earth, 184.
Mushrooms, 189.

Mylae, 142. Town on N. coast of Sicily, near Messina.
Myndus, 274, 290. Town in Caria.

Naples, partly damaged by earthquake of A.D. 63, 221.

Narcissus, 164. Freedman of Claudius, put to death by
Agrippina, 54.

Natural Philosophy, 3, 8.

Nature, influence of, 3 ; origin of, 7 ; as a synonym for God,
92 ; advantage of the study of, 113, 265 ; finds no task
hard, 144, 154; inadequate conceptions of, 228; study

362 PHYSICAL SCIENCE

of, the highest pursuit, 230; power of variation in, 301 ; in-
exhaustibility of, 306; still most imperfectly known, 306.

Naval wars denounced, 213.

Nebaioth, 208. An Arabian people, put for East in general.
Latin form is Nabataei.

Neptune (Earthshaker), 255.

a Nero Caesar, 25, 235, 290, 294 ; probably referred to, though
not named, 90 (last two sentences).

Nicopolis, 259. City in W. of Greece at entrance to Ambracian
Gulf. The word means " city of victory," something like
our oft-recurrent "Victoria."

Nile, unusual character of, 114, 135, 166; physiological effect
of water of, 140; rise of, 141, 167, 169, 172; course
of, 168, 170, 233; cataracts of, 168; mode of descent
of, 169; delta of, 170, 171; canalisation of, 170;
deposit of, 170, 258; inundation of, 171; supposed
underground supply of, 235; Nero's expedition to the,
235 ; transport of sediment by, 258.

Nonacris, 137. Town in Arcadia.

Notus (Wind), 209.

Nuceria, 221. Town in Campania.

Ocean, 6 (2), 112, 119, 135, 143, 153, 155, 231, 254 (2), 266.
a Oenopides (of Chios), 175. Mathematician and astronomer,

probably contemporary of Anaxagoras, fifth century B.C.
Olympic, 142 (2). Olympia was in Elis.
Olympus, 257. High mountain in Thessaly, Northern

Greece.

Omens, arranged by Providence, 80; from lightning, 82.
Organs (hydraulic), 56.

Ossa, 257. Mountain in Thessaly, Northern Greece.
Ostia, 41. Town at mouth of Tiber; port of Rome.
a Ovid, 114, 133, 148, 165, 168. Latin poet, 43 B.c.-i8.

Parhelia, 35.

Pamphylia, 211. District on S. of Asia Minor.
a Panaetius, 304. Stoic philosopher of Rhodes, friend of

Laelius and the younger Scipio Africanus ; died 1 1 1 B.C.
Paphos, 259. Town on W. of Cyprus.
Parium, 22. Town in Mysia on N.W. of Asia Minor.
Parthians, 5, 215.
Paterculus, 303. His consulship is said to have been in the

year 60.

Patras, 257. Town at entrance of Gulf of Corinth.
Paulus, 9. L. Aemilius P., consul 181 and 168 B.C.

INDEX 363

Peacock, analogy from colours of, 25.

Peloponnesian (War), 256, 258. Lasted 431-404 B.C. between
Athens and Sparta.

Peneiis, 138, 257. Great river draining the plain of
Thessaly and flowing through vale of Tempe between
Olympus and Ossa ; now called Salambria.

Perseus, 9. Last king of Macedonia, 178-168 B.C.

Persia, 208, 215.

Persians, 254.

Pestilential vapours emitted from the ground, 260, 261.

Pharos, 258. Island off Alexandria with famous lighthouse,
united to mainland by Alexander the Great.

Phasis, 174. River of Colchis at E. of Black Sea.

Philae, 168 (3), 169. Island in the Nile, just below
First Cataract. Seneca seems to confuse it with the
so-called island of Meroe, at the junction of the Blue
Nile and Atbara.

Philip, no, 207 (2). Father of Alexander the Great ; king
of Macedonia 359-336 B.C.

Philosophers, debt due to the early, 230 ; credulous folk,
258; severe criticisms of, 125, 175, 288, 289.

Philosophy, divisions of, 3 ; pleasures of, 4, 5 ; benefits con-
ferred by, 97; delivers its votaries from fear, 225; re-
wards of, 229; decadence of, 307, 308.
a Pindar, 258. Greek poet, 522-442 B.C.

Pithitae, or pithiae (meteors), 38, 40.

Plancus, 1 60. L. Munatius P., a prominent actor in the
civil wars, 48-31 B.C.

Planets, colours of, i o ; enumerated, 275; fixed number of,
284; orbits of, 285; motions of, 288; possibly greater
number of, 297 ; conspicuous movements of, 298.
a Plato, 216.

Pollux, 1 1 ; see Castor.

Pompeii, 221, 259(2).

Pompey, 166 (3). Defeated by Caesar 48 B.C., and assassi-
nated shortly after.

Pontus (district in N.E. of Asia Minor), 141.

Pontus (Black Sea), 153, 176, 180 (?).

Portents from meteors, 9, 228, 259; lightning, 79, 86, 93,

94, 95, 215; eclipses, 228; comets, 272, 290, 302.
a Posidonius, 26, 27, 73, 74, 98 (2), 177, 246, 252, 256, 292,
293. A very distinguished Stoic philosopher, president
of that school. Instructor for a time and friend of
Cicero. Prosecuted physical investigations with great
success. Native of Syria. Lived 135-51 B.C.

364 PHYSICAL SCIENCE

Posterity, great increase of knowledge to be attained by, 298.

Predestination, 85.

Prognostications ; see Portents.

Propontis (Sea of Marmora), 153, 176 (Lower Sea).

Providence, 92, 213.

Puteoli, 133. On coast of Campania.

Pylades, 307. A Cilician; a dancer like Bathyllus.

Pyrenees, 5.
a Pyrrho, 307. Founder of the sect of the Sceptics, native of

Elis ; flourished about fourth century B.C.
a Pythagoras, 307. Flourished in second half of sixth century

B.C.

Pyx, trial of, 180.

Rain, Seneca's observation on descent of, into soil, 117;

share of, in final destruction of the world, 143, 144, 149 ;

seasonal variations of, 179; supposed to be influenced

by incantations, 182.
Rainbow, 16-33.
Rainless countries, 167, 173.
Red Sea, 112, 153, 168.
Regulus, 221. Consul 63.
Reverence, duty of, 304.
Rhaetian, 35. The reference is to wine grown in the N.

of Italy (Cisalpine Gaul).
Rhine, 146 (2), 173, 233.

Rhodians, 142. Island of Rhodes was at S.W. of Asia Minor.
Rhone, 146, 173.
Rivers as political boundaries, 5, 233; sources of supply of,

116; underground, 132, 141, 206, 207, 233, 235;

summer rise of, 141, 173.
Roman, 5, 12, 46, no, 113, 166.
Rome, no, 166, 182, 209, 307.
Roots, disruptive force of, 57.
Rulers, counsel to, 90.

Sacrifice cannot alter fate, 84; to keep off hail, 181.
St. Elmo's Fire, n, 37.
a Sallust, 279. Roman historian, 86-34 B.C.
Sarmatian, 5, 233 (pi.). Roughly speaking, the S. part of

Russia.

Saturn, the planet, 275 (2), 284, 303.
Scipio, 46 (2). The elder Sc. Africanus, victor of Hannibal

at Zama, 202 B.C.
Scironian (Wind), 211.

INDEX 365

Scylla, 153; see Chary bdis.

Scythia, 180, 208. Term used very loosely of region in Central
and Northern Asia, but at times extending to Europe, as
far west as the Danube. Sarmatia of one age was part
of Scythia of another.

Sea, unity of the, 125; coeval with the world, 135; throws
ashore ill-smelling deposits, 142 ; share of, in final de-
struction of the earth, 143, 150; current of, from Black
Sea, 176; subterranean, 234.

Sea and land breezes, 198.

Seafaring, condemned, 216.

Sea-water, purged of its salt within the earth, 1 1 6.

Sejanus, 9. Notorious instrument of Tiberius ; put to death

31-

Sela (gleams in the sky), 39.
Self, bondage of slavery to, 113.
Septemtrio (Wind), 210.
• Sextii, 307. Father and son in the time of Augustus and

Nero respectively ; taught a combination of Stoic and

Pythagorean doctrines.
Sheep, destruction of, during Campanian earthquake of

A.D. 63, 259.
Sicily and Sicilian, 114, 138, 142 (2), 153, 159, 166(2),

235, 262, 263.
Sidon, 256.
Snow, melting in Ethiopia erroneously supposed to be the

cause of the annual rise of the Nile, 173; supplies some

European rivers, 173; on European mountains, 173;

origin of, 178, 179, 182, 186; said to feel colder to

the feet when dry and hard than when slushy and half

melted, 180; artificial use of, 187.
Sophocles, 172.
Soul, divine origin of, 6 ; to be rescued from error and fear

of death, 103.

Sound less rapid than light, 64.
Spain and Spanish, 6, 7, no, 263.
Springs, 118, 121, 127, 136, 142.
Squalls, origin of, 204; short duration of, 281.
Stabiae, 221. Small town on coast of Campania.
Stars, fed by emanations from the earth, 55, 198, 244;

influence of, in human affairs, 81 ; nature of, 273;

transits of, 284; supposed small size of, 288; place of,

in sky, 297 ; varying colours of, 300.
Stars, falling, 10, n, 37, 99, 296.
Statonia, 139. Town in Etruria, about 15 miles from the coast.

366 PHYSICAL SCIENCE

Stoics, 32, 40, 58, 66, 95, 119, 124, 135, 151, 180, 181 (2),

210, 251, 291, 292, 293, 295 (my school).
a Strato, 240. Succeeded Theophrastus as head of the Peri-
patetic school in 288 B.C. Native of Lampsacus in
Mysia on the Hellespont.

Streaks in the sky, 33.

Strymon, 5. River of Thrace and Macedonia (Struma). The
text of the passage is very doubtful.

Styx, 137. River in Arcadia.

Submergence of Helice and Buris, 254, 257, 259, 267, 276,
289; of Atalanta, 256; of Sid on, 256; of other cities
and nations, 267.

Subsolane (Wind), 209.

Sudd, 236 n.

Sulphur, baneful effects of, in water, 134; supposed to warm
water, 136 ; exists in large quantity underground, 206.

"Sulphur smell" produced by lightning, 69, 97.

Sun, size of, 20, 288; eclipse of, 35, 274, 284, 293; draws
his sustenance from the earth, 55, 198, 244; movements
of, 271 ; among the constellations, 301.

Superstition, 271.

Surrentum, 221. Town on promontory in Campania.

Syracuse, 12, 142.

Syria, 138, 288.

Tempe, 137. Vale or gorge in Thessaly; see Pencils.
Temperature of atmosphere, 60, 183, 184; of various waters,

136.

Tension, effects of, 56, 58.
Tentyra, 172. Island in the Nile (Denderah), not far from

Thebes.
a Thales, 124, 125, 174, 233. Of Miletus; may be considered

the father of Greek philosophy, 636-546 B.C.
Thebes, 257. Capital of Boeotia. There was a more ancient

city of the same name in Upper Egypt on whose site are

the modern Luxor, Karnak, etc.
a Theophrastus 122 (3), 129, 138, 139, 141, 172,240,303.

Of Lesbos, favourite pupil and successor of Aristotle,

head of Peripatetic school, 322-287 B.C.
Therasia and There (Thera), 252. Small volcanic islands in

the group called Sporades, S. of Cyclades.
Thessaly, 137, 257.

Thrace and Thracians, 5, 161, 173, 254.
a Thucydides, 256, 258.
Thunderings, 62, 67; different kinds of, 75; causes of, 98.

INDEX 367

Tiberius Caesar, 41.

Tigris, 142, 235.

Time, wasting influence of, 238, 253; fleetingness of, 268.

Trade to Atlantic ports, 175.

Transmutation of the elements, 120, 121.

Troglodytes, 173. Cave-dwellers, specially applied to tribes

on W. of Red Sea.
Tuscans ; see Etruscans.
Tyre and Tyrian, 27, 224, 225.

Unity or continuity, defined, 53.

Universe, defined, 54; impetuous whirl of, 273; ceaseless
revolution of, 281, 294, 299; a harmony of discords, 301.

Vacuum, non-existent in nature, 128.

Vadimonian (Lake), 139. In Etruria, not far from the Tiber,

the Lago di Bassano, now dried up.
Vagellius, 227. Name unknown, probably corrupt.
Valerius Asiaticus, 74. Consul, for the second time, in 46.
Varro, 209 (2). Famous grammarian, antiquarian, etc., 116-

28 B.C.

Venus, the planet, 284.
Vice, conquest of, leads to highest happiness, 5 ; continued

progress of, 46, 187, 306, 307.
Virgil, 28, 35, 114, 142, 165, 209, 241, 253, 258.
Virginius, 221. Consul 63.
Vitellius, 1 60. Name doubtful; may refer to father of

Emperor Vitellius, who flourished under Caligula and

Claudius, being consul in 34.
Volcanic eruptions, 73, 74, 77, 252.
Vopiscus,- 303. Consul 60.
Vultur, 209. Mountain on borders of Apulia.
Vulturnus (Wind), 209.

Wars, denunciation of, 213, 214.

Water, forms of, 114, 115, 233; transformed into air, 120;
formed from earth, 120; as one of the four elements,
124; Thales' opinions on, 124, 231 ; underground sources
of, 126, 233, 234, 235 ; various tastes of, 133 ; petrifying
powers of, 133; varying temperatures of, 136; artificial
heating of, 136 ; baneful kinds of, 137 ; dyeing properties
of some kinds of, 137; varying densities of, 138;
supposed physiological effects of some, 140; in mines,
154; produces animal and plant life, 197; as the cause
of earthquakes, 231, 233, 234.

368 PHYSICAL SCIENCE

Watergalls and sun-dogs, 33.

Weather indications, u, 14, 15, 28, 37, 39, 75, 181, 275,
302, 303.

Wells and their water-supply, 118, 123, 128; warm winter
temperature of, 176, 241.

Whirlwinds, 204, 275, 276, 278, 279, 280, 281, 282.

Will, freedom of the, 85, 86.

Wind, definition of, 193 ; Democritus' view of origin of, 194;
origin of, 196, 200, 203, 204; within the earth, 205,
206, 239, 243, 244; number and names of the winds,
208-212 ; ideological design of, 212, 216 ; misuse of, by
man, 216; beneficial influences of, 216; disruptive
energy of, 252.

Winds, 208-211. The following are specified: Africus,
Aquilo, Argestes, Atabulus, Auster, 'A^T/Atom?? ( = Subso-
lane), Boreas, Cataegis, Circius, Corus, Etesian, Euronotus,
Eurus, Favonius, lapygian, Kcu/aas, Libonotus, Libyan,
Notus, Scironian, Septemtrio, Subsolane, Thracias, Vul-
turnus, Zephyrus.

Wine, frozen by lightning, 79, 97.

World, revolution of, 20.

a Zeno, 291. Native of Cyprus, founder of the Stoic philosophy,

lived between middle of fourth and third centuries B.C.
Zephyrus (Wind), 208.
Zodiac, 285, 291, 296.

THE END

Printed by R. & R. CLARK, LIMITED, Edinburgh.

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