believe in atoms and void, hold that the world is neither living nor is
governed by Providence, but by " Nature " which is without intelligence
tie rim aXo7^).' ' De Plac.,' ii. 3. Again, Siobaeus (p. 442, Gais-
ford) says, o'i p,ev aXXoi TTCLVTI^ t^v^ov rbv Koa^iov /cat irpovoig. SIOIKOVHSVOV.
e Kai ArjfioKpirog ical '^TriKOvpoQ ovSsTfpa TOVTWV, fyvaei de dX6y<), tic
arb\i(i)v avveaT&Ta, this meaning (rbv Koo/tov), s dro/zwv ouvforwra, 0w<T6i
flaQai). Both passages show how ancient philosophers re-
garded the atomic theory, as essentially and of necessity atheistic.
But whatever Lucretius's professed creed as an Epicurean convert may
be, the world was something greater to him, in virtue of his gift of
poet and of all therein implied, than it was or ever could have been to
Epicurus.
4 Epicurus's language might sometimes warrant a similar conclusion,
as when he says that the world might perish after the fashion of a living
creature, or of an animal. ETTI'KOVJOOC TrXei'oor rpoTroiQ TOV Koafiov tyOtipeaOai'.
Kal yap wt; %u>ov Kai w QVTOV Kai TroXXaxwf. Stob., * Phys.,' p. 414. But
perhaps these words merely mean that Epicurus, as his manner so often
was, left this subject too an open question.
5 See i. 1052-82, the text of which is unfortunately very imperfect.
Munro's note is as follows : * It is the Stoics, doubtless, whom Lucretius
here mainly attacks, though the Peripatetics and some others held a
150 THE ATOMIC THEORY OF LUCRETIUS.
absolutely at rest, to be relatively so. Lucretius will not hear
of any such principle as gravitation towards a centre of the
universe. ' Through centre or no-centre alike heavy bodies
must move downwards.' They cannot rest upon void, and it is
against their nature to move upwards. 1 This explanation is
the one approved by Lange. 2 Though it is the easiest and
certainly the most apparent, still it is not the one most con-
sistent with the doctrines of the Epicurean system. In the
first place, it must be remembered 3 that Lucretius conceives
the world to be exceedingly buoyant, since its heavy core, the
earth, is surrounded by an outer envelope of ether and air,
which, by their extreme lightness, diminish the action of
gravity upon it, and ' cause the weight of the earth gradually
similar doctrine ; they taught that there was but one finite world sur-
rounded by an infinite void ; and that the world was upheld in the way
which Lucretius so clearly explains here, by things pressing to the centre :
the earth resting iVoKparwf, in the words of Zeno in Stob., * Eel.,' i. 19, 4, at
about the centre of the /c6<r/ioc, in the same way that the whole finite KOV/JIO
remains fast in the infinite void. Had Epicurus, while retaining his concep-
tions of infinite space and matter and innumerable worlds and systems,
seen fit to adopt this Stoical doctrine of things tending to a centre, and
so to make his atoms rush from all sides of space alike .towards a
centre, he might have anticipated the doctrine of universal gravity.'
Again, Mr. Munro remarks on ii. 251-93, ' In a curious memoir of the
Berlin Transactions for 1782, by G-.L.Le Sage, called "Lucrece Neutonien,"
the author ingeniously argues that if Epicurus had had but a part of the
geometrical knowledge of say his contemporary Euclid, and conceptions
of cosmography the same as those of many then living, he might have
discovered the laws of universal gravity, and not only the laws, but, what
was the despair of Newton, its mechanical cause. Had he supposed the
earth to be spherical, and made his atoms move in directions perpendicular
to the surface of a sphere, that is towards its centre, he might not only
have proved the law of the inverse square of the distance, but have
demonstrated the cause of that law.'
1 Of. the argument at ii. 184-215, immediately preceding the proposition
as to the action of gravity. Lucretius here refutes the Aristotelian concep-
tion of a centrifugal upward motion.
2 ' History of Materialism,' vol. i., c. 3.
3 Chapter IV., 4.
HOW LUCRETIUS CONCEIVES THE WORLD. 151
to pass away and be lessened.' l In the second place, as we
have seen, Lucretius conceives the world to be kept in being
'by blows,' plagis that is to say, by the constant supply of |
atoms rising up from below, and striking upon it from without. \
But plagae, the blows of the atoms, effect something more
than this. Lucretius has made no positive statement on the
point ; but from one or two passages it may be inferred 2 that
these blows of the atoms, constantly rising up from beneath
and striking upon the earth, have the effect of keeping it
suspended in its place in the universe. When we remember
that Lucretius conceives the world as a whole to be ex-
ceedingly buoyant, and the natural gravity of the earth in
this way to be greatly reduced, it seems clear that he sup-
posed the upward impulse, given by the atoms ever ascending
to feed the world, to be enough entirely to counteract the
action of gravity upon it, and thus to keep it in its place in
the universe, floating as it were in one spot amid the infinite \
sea of matter.
Terraque ut in media mundi regione quiescat,
evanescere paulatim et decrescere pon<Jus
convenit. v. 534-6.
2 In the passage above referred to
illud in his rebus longe fuge credere, Mem mi,
in medium summae, quod dicunt, omnia niti,
atgue ideo mundi naturam stare sine ullis
ictilus externis, i. 1052-5.
when we remember that Lucretius has just proved the necessity of matter
rising from beneath, and that he is here refuting the Stoic doctrine that
the world is kept in the centre of the universe by the pressure of all things
towards that centre, it is difficult to resist the inference above expressed.
It is evident that Lucretius has left this section of the poem unfinished, if
not incomplete.
CHAPTER IX.
THE DE RERUM NATURA AT ONCE A POEM AND A WORK
OF SCIENCE.
T NLIKE other books of which the subject-matter is
y^J mainly scientific, Lucretius's poem has a twofold aspect,
one being its relation to science, and the other its relation to
literature.
It is impossible to study the c De Rerum Natura' without feel-
ing that, entirely apart from its theological motive, Lucretius
shows a keen^intellectual passion for scientific research. It is
a vivid delight to him f( to make his way into nature's secret
hiding-places,'
caecasque latebras
insinuare omnis, 1
and he glories in his master Epicurus having been the first to
e burst open the fast bars of nature's doors,'
effringere ut arta
naturae primus portarum claustra cupiret. 2
Beyond question he shows much of the genuine scientific
method in the manner according to which he pursues his
inquiries. The modern scientific man may indeed smile at the
air of rigid and unswerving scientific method which Lucretius
sometimes assumes, while in the act of giving for some fact of
nature an explanation which we can now easily see to be arbi-
trary and baseless. At the same time, Epicurean science de-
serves the credit of a careful and methodical examination of
1 i. 407. 2 i. 70-1. .
SCIENCE AND POETRY. 153
many natural phenomena, and of conclusions regarding them,
which are as accurate as without the help of experiment could
be looked for, and are often surprisingly near the truth. 1 If
we take, for example, Lucretius's explanation of the cause of
thunder, or of earthquakes, or of the eruptions of Aetna, we
find a most praiseworthy accuracy in observing and collecting
all the facts of such phenomena, and stating these simply and
as they bear on each other. He next discusses the possible
causes at work, explaining the mode of operation of each from
what we daily observe in the world, and fixes shrewdly enough
on the actual one.
These qualities are specially noticeable in his explanation of
the way in which the magnet attracts iron. 2 He first reminds
us that minute particles are constantly streaming off the sur-
face of every substance. These emanations never cease. The
afflux of particles from the magnet is quite unlike that from
any other body. There proceeds constantly out of it an ex-
ceedingly violent current of atoms so strong that it pushes
out the air and creates a vacuum in front of the magnet. Then,
when a ring of iron is placed near the stone, a great number of
particles of the iron rush forward into the vacuum. 3 Since no
other substance is formed of atoms more intricately entangled
or more solid than those forming iron, in consequence of this
peculiarity of its atomic structure, when a large stream of its
particles have moved forward, the whole mass cannot help
speedily following. But why should the iron rush into the
empty space ? The reason is that the air ' beats on ' (verberat)
1 This does not hold good of Epicurus's notions about astronomy. Here
he was far behind his age. Epicurus simply ignores the discoveries of
Eudoxus, who was born a whole generation before him.
2 vi. 906-1089,
extemplo primordia ferri '
in vacuum prolapsa cadunt coniuncta
Mr. Munro translates, ' forthwith the first-beginnings of iron fall head-
long forward into the void in one mass.'
154 THE ATOMIC THEOEY OF LUCEETIUS.
every substance on all sides, and wherever a vacuum is formed,
the pressure on every side naturally forces the iron in the one
direction where a passage is open. Moreover, the very resist-
ance offered by the solidity of the iron makes the air more
active in forcing it- on. The air penetrates into its passages,
and striking on its substance impels it forward from within as
well as from without. ( The air makes its way subtly through
the frequent pores of the iron even to its minute parts, and
thrusts and pushes it on as does the wind a ship and its sails.' l
In another way, too, the air inclines the iron to move. All
substances are porous, and therefore must have air within them.
This inner air is constantly moving to and fro, and makes a
stirring in the substance of the iron. Thus, as soon as the iron
has begun to move under the influence of the magnet, the
motion of the inner air tends to carry it onward. Why, then,
is iron attracted, but not other things ? Some substances, like
wood, are so porous that the streams of air, instead of pushing
them forward, flow right through them. Lead, again, is too
heavy to be carried forward in such a way.
Lange finds the following difficulty in Lucretius's explana-
tion : { How is it possible that the currents from the magnet
can expel the air without repelling the iron by the same force ? '
But Lucretius has specially guarded against this very objection
(at 11. 979-97). He points out that the pores of different bodies
differ widely. ' The nature of the passages ' allows one thing
to pass, but refuses to admit another to enter the same sub-
stance. Thus the current from the magnet f swims through ' a the
1 We may compare iv. 877-906, where Lucretius, in explaining how the
human body is set in motion Toy f|m will, fl.p-a.in assigns a secondary part
to the air in assisting and increasing motion after it ha,a Jiegnn. When
the human body has begun to moveTits pores are openefl fhow nrjvhy
Lucretius does not say), and theTair, which is ever ready 'to enter, flows in
p-rfla.f, (paniitY jnto the inmost parts ofthe body, and striking on its sub-
stance impels it onward, just asthe wind beating on the jaijjljavefl on a~dhip.
2 tranet (vi. 1052). So of ^images ', which can passthrough glass, be-
cause its pores are straight and parallel (Recta foramina tranant. iv. 601).
SCIENCE AND POETRY. 155
pores of the iron because there is a special adaptation between
the structure of these pores and the particles of the magnetic
current. 1
After Lucretius has given us his explanation, no doubt we
are still disposed to ask many questions. At the same time,
as Lange has said, Lucretius deserves credit for explaining
the magnet's operation not by the assumption of any mystical
horror vacui, nor yet of any secret force or special sympathy,
but as a consequence of the specific gravity and structure of
the iron. This praise is well deserved. -According to his
fifth proposition, as we have seen, there is nothing but matter
and void in existence. Therefore Lucretius is not misled
by any notion of magnetism as an e element ' by itself, or a
6 special fluid ' or f principle ' of one kind or another. He treats
the phenomena of magnetism simply as properties of matter
residing in the molecules of the magnet. Here we see how
great is the vantage-ground of Epicurean science. 2
1 According to Diogenes L. (ix. 47), Democritus wrote a treatise on the
magnet which no doubt influenced Epicurus. Democritus, says Zeller,
* thought that the magnet and the iron consist of atoms of similar nature,
but which are less closely packed together in the magnet. As, on the
one hand, like draws to like, and on the other all moves in the void, the
emanations of the magnet penetrate the iron and press out a part of its
atoms which, on their side, strain toward the magnet and penetrate its
empty interspaces. The iron itself follows this movement, while the
magnet does not move towards the iron because the iron has fewer
spaces for receiving its effluences ' (' Pre-Socratic Philosophy,' vol. ii, p.
230, Eng. tr.). Democritus followed in the footsteps ofEmpedocles, who
asserted the atoms of both substances to be similar, and ' supposed that
after the emanations of the magnet have penetrated into the pores of the
iron, and the air which choked them had been expelled, powerful emana-
tions from the iron pass into the symmetrical pores of the magnet, which
draw the iron itself and hold it fast ' (Zeller, ib., p. 134). On this subject
see Alex. Aphr., * Quaest. Nat'.,' ii. 23.
2 Lucretius's explanation shows how his favourite doctrines, such
as the streaming of emanations from all bodies and the porousness
of all matter, could be made practically serviceable as working hypo-
theses. * He dwells on the magnet at what appears so disproportionate a
156 THE ATOMIC THEORY OF LUCRETIUS.
One very characteristic feature of Lucretius's poem, in
point of literary treatment, is the admirable power of illus-
tration by which he can bring home to us a scientific doctrine
through the means of something going on before our eyes
in the- world. Putting aside their beauty of poetic expres-
sion, these illustrations are in each case singularly close
to the point. Their accuracy shows that, as Professor
Tyndall has said, Lucretius possessed a strong ' scientific
imagination. '
For example, this is how he illustrates the doctrine that
the fl.tnnip ^re^eternally in motion, even though matter appears
to our eyes to be at rest : s Thus often the woolly flocks
as they crop the glad pastures on a hill, go creeping on
whither the grass gemmed with fresh dewdrops invites and
attracts each one, and the lambs full-fed are gambolling and
butting each other in play; all which objects appear to us from
a distance to be blended in one, and to be like a white spot
resting on the green hill.' A second illustration of the same
doctrine is taken from the pageantry of war. ' Again, when
mighty legions wage a mimic war and cover the plains with their
swift movements, there the glitter rises to the sky, and the whole
earth around gleams with brass, and beneath a noise is raised
by the mighty trampling of men, and the mountains, smitten by
the s"houting, fling back their voices to the stars of heaven,
while the horsemen hurry to and fro on the flanks, and
suddenly charge across the plains, shaking them with their
mighty onset.' l How vividly Lucretius makes us see the
legions in evolution, with their armour flashing in the sun,
length, because the phenomena seem to him to illustrate so many of his
favourite first principles. The elaborate criticism in Galen., 'De n'at.
facult.,' i. 14, of Epicurus's theory of the magnet, extending over many
pages, proves that the latter must have dwelt on the subject at as great
length as Lucretius does, and that he explained the phenomena in a
similar manner ' (Munro on vi. 917).
1 ii. 317-30.
SCIENCE AND POETRY. 157
and hear their mighty tread ! But still more impressive are
the two following lines
et tamen est quidam locus altis montibus undo
stare videntur et in campis consistere fulgor.
' And yet there is some place on the high mountains, from
which they appear to stand still and to be a bright spot at rest
on the plain.' In two short lines Lucretius shows us how
small is all human activity, in mere bulk, as compared with the
vastness of nature ; the mighty legions with their thousands of
men constantly marching and counter-marching at full speed,
seen a few miles away, appear only a small bright spot. Yet
he could have chosen no better illustration to bring home to
us how the tiny atoms may be in the most violent and con-
stant motion, while the matter which the^Tmild up appears
to us to be at rest.
While these illustrations are thickly scattered over the
poem, when we come to examine them singly, we find that
every one strictly illustrates the doctrine under which it is in-
troduced. Lucretius enjoys weaving them in as pieces of
pleasant colour into the somewhat grim framework of his poem
but not one is introduced merely as an episode. In each case
the illustration makes plain to us a point which without it we
should feel difficult to grasp. If we examine any one, we find
how strictly it bears on the special doctrine under discussion.
For example, that of the cow whose calf has been taken away
to be sacrificed, and which keeps searching everywhere, return-
ing again and again to wood and pasture and stall in the hope
of recovering it. How does Lucretius introduce this, one of
the most pathetic passages in all literature ? It occurs in the
strictest sequence. Lucretius is proving that the atoms are
not all of one pattern, but that they are of many different
shapes, and that this diversity explains why each individual
of every species of living things differs from the other in
appearance and form. Thus the animals recognize each other's
158 THE ATOMIC THEOEY OF LUCRETIUS.
individuality as much as human beings do every parent knows
its own offspring, and the cow robbed of its calf can never be
satisfied by the substitution of any other, 1 but seeks persis-
tently ( something special and known.'
1 We quote Mr. Munro's admirable rendering of this passage : * And
in no other way could child recognize mother or mother child ; and this
we see that they all can do, and that they are just as well known to one
another as human beings are. Thus often in front of the beauteous
shrines of the gods a calf falls sacrificed beside the incense-burning altars,
and spirts from its breast a warm stream of blood; but the bereaved
mother as she ranges over the green lawns knows the footprints stamped
on the ground by the cloven hoofs, scanning with her eyes every spot to
see if she can anywhere behold her lost youngling ; then she fills with her
meanings the leafy wood each time she desists from her search, and again
and again goes back to the stall pierced to the heart by the loss of her
calf: nor can the soft willows and grass quickened with dew and yon
rivers gliding level with their banks comfort her mind and put away the
care that has entered into her, nor can other forms of calves throughout
the glad pastures -divert her mind and ease it of its care : so persistently
does she seek something special and known ' (ii. 349-66).
There must at bottom have been a kind and loving nature in the man
who could read so keenly the signs of suffering in the animal creation as
Lucretius has here done. Is there not something specially tender in the
touch which tells us how not even the pasture-ground with its dear and
familiar landscape the drooping willows, the cool and dewy grass, and
the river gliding past brimful could make the cow forget her sorrow ?
If animals have any distinct love for the spot where they have been bred,
surely it is bound up with just .such associations of shelter, ease, and
plenty. Too often we ignore the unhappiness which at times the lower
creatures must suffer. Does not Lucretius actually dignify the suffering
of the poor dumb creature, in its cruel bereavement, simply through the
human sympathy with it, which he is not ashamed to express ? In
Lucretius's readiness to realize by imagination and to feel for the suffer-
ing, the pain, and the fear which must exist alike among men and among
animals, all over a world like this where ' the whole creation travails to-
gether in pain,' there is an almost modern note. Thus, for instance,
when he speaks of the lonely places of the earth, which are ' filled with
quaking and terror ' because of the fierce beasts of prey which the other
creatures dread
ita ad satiatem terra ferarum
nunc etiam scatit et trepido terrore repleta est
per nemora ac montes magnos silvasque profundas.
SCIENCE AND POETRY. 159
Lucretius's poem shows that he must have been a close
observer of nature. The manner in which he musters facts
from all quarters to illustrate any given doctrine shows what a
grip he could take of general principles. Beyond question, in
this way he contributed something to the science of Epicu-
reanism beyond what he found in the treatises of his master.
For example, when he is explaining the different sounds of
thunder as the noise produced by the clouds, when buffeted or
burst by the wind within them, he gives, as an instance of
sound produced in a similar way, the loud flapping of a canvas
awning over a large theatre, when it is tossed up and down by
the wind, or again, the harsher sound heard when the wind
tears it. Again, he shows in the following way that there are
forces in nature which we cannot see except in their working. 1
First of all, he describes a violent storm, and points out that
the wind, though its particles are minute, acts in exactly the
same way as a stream in flood. Further, he says, we perceive
smells, though we cannot discern their cause. Clothes hung up
by the sea-shore become moist and are dried again by the sun,
though we see no particles either come or go. In course of
years the ring worn on a finger grows thinner, the dripping of
water from the eaves hollows a stone, the pavement in the
street is worn down by the feet of the passers-by. The hand
of the brazen statue at the city gate is wasted away by the
touch of those who salute it. The rocks by the sea-shore are
eaten away by the salt spray, but we can perceive this gradual
waste no more than we can discern the slow gradual increase
occurring in the growth of plants. In all these cases we are
certain that things have become worn away, but ' the nature of
vision ' prevents us from seeing the particles which, at any
given moment, disappear. Thus Lucretius proves that
* Nature works by unseen bodies,'
corporibus caecis igitur natura gerit res.
1 i. 265-328.
160 .THE ATOMIC THEORY OF LUCRETIUS.
These . facts from Lucretius's daily observation by field
and shore and street appear homely enough when thus ab-
stracted, but they one and all bear rigidly on the point which
he is illustrating. At the same time, how comes it that Lucre-
tius's river in flood and torrent of storm in the air never remind
us of the illustrations which are so plentiful in the modern
science text-books? They are not mere diagrams to illus-
trate his text, but pictures drawn for us to see.
f The force of the wind when roused beats on the harbours
and sinks huge ships and scatters the clouds ; sometimes it
rushes over the plains in a swift whirlwind and strews them
with great trees and lashes the mountain-tops with forest-
crashing blasts : so madly does the wind rave with shrill
howling and rage with a threatening roar. 1 Winds therefore,
beyond question, are unseen bodies. . . . They stream on and
spread destruction abroad in just the same way as does the
soft and yielding water when, in time of flood, down it rushes
all at once in a torrent, while a great downfall of water
from the high hills feeds it with copious rains, hurling together
the fragments of the forests and whole trees : nor are the
strong bridges able to sustain the sudden assault of the flood
coming on, in such wise does the river, wild with much
rain, dash against the piers with mighty force, and overthrow
them with loud crash, and roll along the great stones beneath
its billows ; wherever anything opposes its waves, it hurls it
down. In this way, then, must the blasts of wind, too, rush
along.' 2 Lucretius's picture of a river in flood is a perfect
1 Or, if the MS. reading be correct,