Starts to break up a cloud, but cannot do it;
It then depresses it, and it becomes
Like a column let down from the sky into the sea,
Slowly, as though a fist thrust by an arm
Were pushing something down, and spreading it
435
Into the waves; then when the wind has burst it
It rushes out upon the sea, and makes
A wondrous boiling in the waves below.
For the whirlwind turns as it comes down, and brings
The cloud down with it, a soft and yielding body.
But as soon as it has thrust the teeming cloud
440
Down to the ocean’s surface, then at once
The whirlwind plunges into the water and stirs up
The sea all round and makes it boil and roar.
Sometimes a whirlwind wraps itself in a cloud
Scraping together seeds of cloud from the air,
And behaves like a prester let down from the sky.
445
When this has reached the earth and broken up
It vomits out a monstrous violence
Of mighty whirling wind and rushing storm.
But since this occurs quite rarely, and on land
The view of it must often be blocked by mountains,
It is seen most frequently upon the sea
With its wide prospect and its open sky.
450
Clouds form when in the expanse of sky above
Many flying atoms come together
All at once, and these are rougher, and so although
They tangle together lightly, that is enough
To hold them firmly fixed and joined together.
From these at first small clouds are formed; these then
455
Take hold of one another and band together,
Then join and grow, and the winds drive them on
Until in time a furious storm builds up.
Now let us look at clouds on mountain tops.
The closer the crests are neighbours to the heavens,
The more from their exalted seats they smoke
460
With the thick darkness of the tawny cloud.
This is because when first the clouds are formed,
Before the eye can see them, so thin they are,
Winds drive and lift them to the mountain tops.
At length then, massed together and condensing,
465
They become visible, and appear to rise
From the mountains’ very top into the ether.
For our own senses and the facts themselves
Make evident to us when we climb high mountains
That these lofty places are open to the winds.
And nature makes a constant stream of atoms
To rise up from the surface of the sea,
470
As is shown by clothes that hung out on the shore
Grow damp and sticky. This suggests that clouds
Also can grow by receiving many atoms
That rise up from the ocean’s briny swell,
For these possess a similar kind of moisture.
475
Besides, from all rivers and from the earth itself
We see mists and vapours rise, which, drawn up from them
Like breath, move upwards and fill all the sky
With gloom, and gradually as they come together
Bring up supplies to the high clouds above.
480
For the heat also of the starry ether
Presses down on them from above, condensing them,
And weaves a curtain of cloud beneath the blue.
Lastly, those atoms which make clouds and storm-rack
Sometimes come into our sky from outside.
For I have proved that their number is innumerable,
485
And that the sum of space is infinite,
And I have shown the great velocity
With which the atoms fly, and how in an instant
They cover distances beyond all telling.
No wonder is it then if storm and darkness
490
Often so swiftly, with great thunderclouds
Poised overhanging, cover land and sea,
Since everywhere through the channels of the ether
And as it were through all the breathing-holes
Of the great world around, the atoms are free
To make their exits and their entrances.
Now let me demonstrate how rainy moisture
495
Condenses in clouds high above, and falls
In a shower of rain upon the earth beneath.
First you will concede that many atoms of water
Rise up together with the clouds themselves
From things of every kind, and in this way
Both grow together, the clouds and whatever water
500
Is in the clouds, just as our bodies grow
Concurrently with the blood and sweat and whatever
Moisture there may in fact be in the limbs.
Also the clouds often take up a quantity
Of sea water, like hanging fleeces of wool,
When the winds drive them above the mighty ocean.
505
In a similar way moisture rises to the clouds
From every river. And when into the clouds
Many atoms of water have in many ways
Joined up together, increasing everywhere,
The clouds stuffed full strive to discharge the moisture;
For two reasons: the wind compresses them,
510
And the clouds themselves, collecting into a mass
Larger than usual bear down and press
Down from above and make the showers flow out.
Besides, when clouds are thinned out by the wind
And dissipated by the sun’s heat from above,
They send out rainy moisture, and drip, as wax
515
Over a hot fire melts and liquefies.
A downpour comes when clouds are strongly pressed
By both these forces: by their own mass piled up
And by the strong power of the rushing winds.
Long and persistent rain occurs when atoms of water
520
Are set in motion in great multitude
And clouds on clouds are carried streaming down
In universal rainfall everywhere
And all the earth smokes and breathes back the moisture.
And when the sun amidst the gloomy storm
Shines with its rays upon the falling drops
From black clouds opposite, then there stand out
525
Amid the clouds the colours of the rainbow.
And all those other things that grow above
And are created above and collect in the clouds,
All, absolutely all of these, snow, wind,
Hail, freezing front, and ice’s mighty power,
Great hardener of waters, impediment
530
That everywhere reins back the eager rivers—
To find these out and picture in your mind
How they are all produced and why they are made
Is very easy, once you have fully grasped
The different natures of their elements.
Come now, and learn the causes of earthquakes.
535
First, you must get into your mind that the earth
Below us, as above, is everywhere
Full of windy caves; and many lakes and pools
She bears in her bosom, and rocks and beetling cliffs,
And many hidden rivers beneath earth’s back
540
Roll their rough currents over sunken rocks.
For the facts themselves require that everywhere
Earth should be like herself, above an
d below.
With these things therefore joined to it below
And placed beneath it, earth trembles with the shock
Of vast collapse and ruin when age and time
545
Have undermined the mighty caves below.
Whole mountains fall, and from the mighty shock
Tremors spread abroad in an instant far and wide;
Quite naturally, since buildings by the roadside
Tremble with the shock of waggons passing by
Of no great weight, and jump when the iron-shod wheels
550
On either side jolt over stones or potholes.
And sometimes also when some enormous lump
Weakened by time rolls forward from the earth
Into some huge wide pool, the earth itself
Sways shaken by the wave of water, as a jar
555
Sometimes cannot stand still unless the water
Inside has stopped from moving to and fro.
Besides, when through the hollows below the earth
A wind collects, and thrusting in one direction
Bears down and drives into the lofty caverns,
The earth leans under the impact of the wind.
560
The houses that are built up on the earth,
And all the more the more they tower to heaven,
Lean dangerously, bulging and pushing forward
In the same direction, and the beams askew
Hang in the air projecting, ready to go.
And yet men fear to believe that the great world
565
Has waiting for it some disastrous hour
Of ruin and destruction, though they see
So great and mighty a mass of earth lean over!
And yet unless the winds abate, no power
Could curb the world’s rush to ruin and hold it back.
But since in fact the winds alternately
570
Abate and gather strength, and as it were
Collect their forces and rally, and then retreat
Repulsed again, more often for this reason
Earth threatens to fall than it actually does fall.
For it leans forward and then again springs back,
And after falling forward it recovers
Its proper place and stands in balance again.
This is how all buildings totter, the top
575
More than the middle, the middle more than the base;
The base itself is hardly moved at all.
These mighty tremors have another cause.
When wind and some great sudden force of air
Either from outside or within the earth itself
Has hurled itself into earth’s hollow places
580
And there, inside the mighty caverns, first it roars
Tumultuously and rushes whirling round,
Then with its violence intensified
And agitated, out it bursts, and cleaves
Earth to its depths and makes a mighty chasm.
This is what happened at Sidon in Syria
585
And Aegeum in the Peloponnese. Both cities
Were rocked and torn by such an issue of air,
And demolished by the earthquake that took place.
And many another city wall has fallen
By mighty movements of the earth, and many
Cities of men with all their citizens
Have sunk down to the bottom of the sea.
590
But if no burst occurs, yet the strong wind
And violent force of air is disturbed
Through all the many passages of the earth,
Like a shudder, and this creates the tremor,
Just as when cold comes deep into our limbs
It shakes them and makes them tremble against their will.
595
So in their cities men are disquieted
By twofold terror: they fear the houses above,
They dread the caverns beneath, lest suddenly
Earth fling them open, or splitting wide apart
With gaping jaws create a mighty chasm
And fill it with the ruins it has made.
600
Therefore let them believe, however they please,
That earth and sky are incorruptible
And stand destined to everlasting life,
Yet sometimes comes a very present danger
To stab them with the fear that suddenly
Earth may withdraw beneath their feet and fall
605
Into the abyss, and all the sum of things
Follow in total collapse, and then may come
The ruin and confusion of the world.
Some people wonder that nature does not cause
The sea to increase in size, since into it
Runs down so great a flow of water, and since the rivers
All flow into it from every part of the globe.
610
And add the wandering showers and flying storms
That spatter and water every land and sea;
Add too the sea’s own springs; yet all of these
Compared to the sea’s great mass will scarcely equal
The addition to it of a single drop.
This makes it then the less a matter for wonder
That the great sea does not grow greater still.
615
The sun’s heat also draws a great part off.
For certainly we see clothes dripping with water
Dried by the strong rays of the burning sun.
But seas are many, and spread wide below;
Therefore, however small a part the sun
620
May sip from off the surface of the sea
In any single place, yet from that vast expanse
Abundant store of water is drawn off.
Also much water may be taken up
By winds that sweep the surface of the sea,
Since very often in a single night
625
We see the roads dry out and the soft mud
Form into hard crusts all along the way.
Besides, I have shown that clouds also lift off
A mass of moisture from the ocean’s surface
Which on the whole world everywhere they sprinkle
When rains fall on the earth and wind drives the clouds.
630
Last, since the earth is of a porous texture,
And everywhere, joined closely to the sea,
Encompasses its shores on every side,
Then, just as water comes from land to sea,
So it must ooze from the salt sea into the earth.
The brine is filtered off, and the mass of water
635
Oozes back and joins the rivers at their source,
And thence in a column of sweet water
Over the ground it flows, along the path
Once cut by liquid foot to guide the waters.
And now the fires that from Mount Etna’s throat
Breathe out at times in such a furious storm
640
I shall explain. No ordinary disaster
The flaming tempest wrought that reigned supreme
Over the fields of Sicily, and neighbouring nations
Looked on it with amaze, as all the heavens
Filled with black smoke and flashing flames of fire
They saw, and trembled, wondering in fear
645
What new things nature might be forging for the world.
These things, my friend, with vision wide and deep
Must be surveyed, and in every part descried.
You must remember that the sum of things
Is deep beyond all telling. You must see
650
How small a part, how infinitesimal,
Our world is of the total universe,
Is of the whole great earth on which he lives.
If you will keep this firmly in your mind,
And clearly comprehend and clearly see it,
There are many things at which you’ll cease to wonder.
For is there anyone that feels surprise
655
If fever rising with its burning fire
Attacks the limbs, or if some other pain
Afflicts the body, caused by some disease?
The foot swells suddenly; sometimes a stab of pain
Shoots into the teeth or even into the eyes.
The fiery rash breaks out, creeping over the body,
660
And burns whatever part it seizes on,
Crawling relentlessly across the limbs.
All this is caused by the multitude of atoms;
For sure this earth and sky of ours contain
Sufficient store of noxious disease
To spawn a growth of ills immeasurable.
In this way we must think that heaven and earth
665
Are from the infinite supplied with all that’s needed
For earth to move and quake in sudden shock
And the swift whirlwind scour the land and sea,
The fires of Etna flow, the sky to flame.
For this does happen, and the realms of heaven
670
Are set on fire; and a heavier fall
Of rain storms down, when by some chance the atoms
Of water have been massed and concentrated.
‘But surely this tumultuous conflagration
Is much too huge for such an origin.’
Well, any river may appear immense
To a man who has never seen a greater one;
675
So does a tree or a man; and everything,
When a man has seen no larger, he thinks vast.
But all these things, with earth and sea and sky
Added together, are as nothing compared
With the sum total of the universe.
Now, none the less, I shall explain the ways
680
In which the flame excited suddenly
Blasts out from Etna’s mighty furnaces.
First, the whole mountain is hollow underneath,
Supported mostly on caverns in the rock.
In all the caves there is both air and wind;
For air makes wind when strongly agitated.
685
Now when the wind has grown extremely hot,
And heated in fury all the rocks around
Wherever it touches, and also the earth,
And struck from them hot fires and rushing flames,
It rises, and straight through the mountain’s throat
Hurls itself upward in a mighty blast.
Then far and wide the heat is spread, and wide
690
The fall of ashes; and in darkness thick
It rolls its smoke, and all the while throws out
Rocks of amazing weight. Beyond a doubt
On the Nature of the Universe (Oxford World’s Classics) Page 28
