On the Nature of the Universe (Oxford World’s Classics) (51 page)

The liquid mass of water and swimming plains?

405

And if he wants us to beware the stroke

Why is he loth to let us see it coming?

But if he wants to crush us unawares

Why does he thunder from the same direction

And put us on our guard? Why does he first

Summon the darkness, with its roars and growls?

410

And can you possibly believe he shoots

In many directions simultaneously?

Or would you dare to say this never happens,

Never many strikes at the same time?

In fact this often occurs, and it must be

That just as rain-showers fall in many places

415

So at one time fall many thunderbolts.

Lastly, why does he wreck the holy shrines of gods

And his own glorious habitations

With hostile thunderbolt? Why does he smash

The noble images of gods, and dishonour

His own fine statues with a violent wound?

420

Why does he mostly strike high ground, why do we see

The signs of fire most often on the mountain tops?

From what has been said, it is easy to understand

Those whirlwinds which the Greeks name from their nature

Presters, and how they come from above into the sea.

425

It sometimes happens that a kind of column

Is let down from the sky into the sea.

The waters boil round it, lashed by furious winds,

And any ships caught in this mighty tumult

Find themselves storm-tossed, in the greatest danger.

430

This happens when sometimes a powerful wind

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