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

by Ronald Melville

  Should not also and all the more fall off;

  Especially since on the outer surface of things

  Are many minute bodies which can be cast off

  In the same order in which they were before

  And keep the shape of the objects, and far more quickly,

  Since they are so much less able to be impeded

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  Being fewer and placed on the extreme outside.

  For many things are thrown off lavishly

  Not only from deep within (as we said before)

  But from their surfaces, among them colour.

  Awnings do this, yellow and red and purple

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  Spread over a great theatre, for all to see,

  On posts and beams, flapping and billowing;

  For then the great assembly massed below,

  The scenes on the stage, the grandees in their boxes,

  They dye, and make to glow and flow with colour.

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  And the more the theatre’s surrounding walls

  Enclose it, the more all things with beauty filled

  Laugh when the light of day is thus confined.

  Therefore, since canvas throws off colour from its surface,

  All other things must equally send out

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  Thin images from the surface everywhere.

  And so there are now fixed outlines of shapes

  Of finest texture which fly all around

  But individually cannot be seen.

  Again, the reason why all smell, smoke, heat,

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  And similar things stream out into the air diffused

  So widely is that they come up from the depths

  And in their tortuous course are split apart,

  And there are no straight openings to the paths

  Of exit, through which they can push out together.

  But on the other hand, when the thin film

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  Of surface colour is thrown off, there is nothing

  To tear it up, because it lies exposed

  And is located on the outer surface.

  Lastly, whatever similitudes we see

  In mirrors, water, or any shining surface,

  Since they possess the same outward appearance

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  As those objects, it follows that they must

  Consist of images thrown off from them.

  There are therefore thin shapes and likenesses

  Of things which singly no one can perceive

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  Yet being flung back by continual

  And instantaneous recoil produce

  A vision from the surfaces of mirrors.

  Nor is there clearly any other way

  In which they could be presented to reproduce

  So accurate a likeness of each object.

  Now I’ll explain to you how very thin

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  Each image is. First since their atoms are

  So far below our senses and so much

  Smaller than those things which the eyes begin

  No longer to see, to confirm this let me explain

  In a few words how exceedingly minute

  The primal elements of all things are.

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  First, there exist some animals so small

  That a third part of them is quite invisible.

  What do you think one of their guts is like?

  The ball of the heart? or the eyes? or limbs and joints?

  How small they are! And what too of the atoms

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  Of which the mind and spirit are composed?

  Do you not see how fine and minute they are?

  Consider also things that from their bodies

  Emit a pungent small—all-heal, rank wormwood,

  Strong southern-wood, astringent centaury

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  If you press lightly a leaf of one of them

  Between two fingers

  [Some lines missing]

  Rather you may know that many likenesses

  Of things are flying about in many ways

  And all beneath the power of our perception.

  Now these similitudes cast off from objects

  Are not the only ones that fly around.

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  Others there are which of their own accord

  Come into being and by themselves are formed

  In this part of the sky we call the air,

  Which formed in many ways are carried aloft

  And melting never cease to change their shapes

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  And form the outlines of things of many kinds.

  We see clouds quickly massing in the sky

  That mar the clear face of the firmament

  Stroking the air as they move. For often giants

  Appear to fly above, casting deep shadows,

  Sometimes great mountains and rocks torn off from them

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  Seem to confront the sun and pass across it

  And then some monster pulling other clouds.

  Unceasingly they melt and change their shapes

  And take the outlines of forms of every kind.

  Now let me tell you how easily and swiftly

  These images arise, perpetually

  Flowing and falling from things and moving away.

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  For there is always something streaming off

  From the surface of things which they eject. And this,

  When it meets some things, passes through them, like glass

  Especially. But when it meets rough stone

  Or solid wood at once it is broken up,

  And then it cannot reproduce an image.

  But when the object opposed is bright and compact

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  As a mirror is, none of these things occurs;

  For it cannot pass through it, as it does through glass,

  And also it cannot be broken up, so much

  Safety the smoothness never forgets to give.

  That is why the images stream back to us.

  However suddenly you place a thing

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  In front of a mirror, at once its image appears;

  So you may know that from the surface of things

  There is a constant and perpetual flow

  Of thin shapes and thin tissues everywhere.

  Therefore in a short time many images

  Come into being, so you may rightly call

  The origin of them instantaneous.

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  The sun must send out many beams of light

  In a short time, to fill the world with it,

  So in one moment many images

  Are borne in many ways into all parts.

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  Whichever way we turn a mirror, something

  Makes answer to us of like form and colour.

  Consider this now: when the weather has been

  Most brilliant, suddenly the sky becomes

  Gloomy and ugly so that you might think

  That all the dark from Acheron had fled

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  And filled the mighty caverns of the sky.

  So foul a night of clouds has massed together

  And the black face of fear lours from on high;

  And the image of these clouds, how small it is,

  No man can tell or reasonably describe.

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  I now explain how fast these images move

  And what velocity as they swim through the air

  Is given them, a brief hour for a mighty space,

  Where each with varied impulse makes its course.

  And this I tell in words both sweet and few.

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  Better the swan’s brief song than that cry of cranes

  Spread by the south wind through the clouds on high.

  First, you may very often see that things

  Light and of minute elements move swiftly.
/>   Of such kind are the sun’s light and its heat

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  Because they are made of minute elements

  Which are hit, at it were, and cross immediately

  The intervening space hit by a blow that follows:

  For instantly light follows light, and flash

  Is triggered off by flash, like a team of oxen.

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  In much the same way therefore the images

  Must be able to run through space incalculable

  In a moment of time; first, since a very small impulse

  From far behind is enough to set them in motion,

  Since with so swift a lightness they rush on.

  Next, since their texture is so very fine

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  That they can easily penetrate anything

  And ooze as it were through the intervening air.

  Consider this too: certain particles

  Which rise from deep down, like the sun’s heat and light,

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  Are seen at the very instant of daybreak

  Through the whole space of heaven to pour themselves

  And fly over land and sea and flood the sky;

  What then of those already on the surface

  When they are thrown off and nothing checks their flight?

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  Faster and further clearly they must go

  And cover a distance many times as great

  In the same time that it takes the sun

  To spread its light abroad across the sky.

  This also especially seems to show most truly

  The speed at which these images are borne:

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  A smooth surface of water is exposed

  To a clear sky at night, at once the stars

  And constellations of the firmament

  Shining serene make answer in the water.

  Now do you see how in an instant the image

  Falls from the edge of heaven to the edge of earth?

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  Wherefore again and yet again I say

  How marvellously swift the motion is

  Of the bodies which strike our eyes and make us see.

  And odours flow perpetually from things,

  As cold from rivers, heat from the sun, and spray

  From the sea which scours the walls along the shore.

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  And always different sounds fly through the air.

  Again, a damp taste of salt enters our mouths

  When we walk by the sea; and when we watch wormwood

  Being mixed with water we sense its bitterness.

  So does from all things always something flow

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  And everywhere into all parts spreads abroad.

  And no delay or rest is given this flow

  Since we constantly feel it, and all things always

  We can see and smell, and hear the sound of them.

  Again, a shape that is handled in the dark

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  Is recognized to be the same we see

  In the clear light of day. It follows then

  That sight and touch derive from a like cause.

  If we touch something square and it stimulates

  Our senses in the dark, what can it be

  That in the light comes to our sight as square,

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  If not an image of it?

  Images therefore clearly are the cause

  Of vision, and without them nothing can be seen.

  Now these images I speak of are flying around

  Everywhere and sprayed about in all directions;

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  But since it is only with our eyes we see them

  It follows that only where we turn our sight

  There all things strike it with their form and colour.

  Also the image enables us to see

  How far away things are, and to distinguish

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  Distances, for when it is sent off

  At once it drives and pushes all the air

  That is between the object and our eyes,

  And this air all passes through our eyeballs

  And brushes the pupils as it were in going through.

  This is the reason why we can see how far

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  Away things are, and the greater the volume of air

  That is driven before it and the longer the stream

  That brushes our eyes, the more distant

  And far removed the thing is seen to be.

  And all this happens extremely rapidly,

  You may be sure, so that at the same moment

  We see both what a thing is and how far away.

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  And here is a thing that need not cause surprise—

  That objects can be perceived though the images

  That strike our eyes cannot themselves be seen.

  For when wind blows slowly on us and bitter cold

  Flows round, we do not feel each particle

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  Of wind or cold, but rather the whole at once,

  And we feel blows falling upon our body, as if

  Something were striking it, and giving us the feeling

  Of its own body coming from outside.

  And when we knock a stone with a toe, we touch

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  Just the outer surface of it and the surface colour,

  But we do not feel this by our touch, but rather

  The hardness of the stone deep down inside.

  Now I will tell you why the image is seen

  Beyond the mirror; for certainly it seems

  To be far withdrawn and lie deeply within.

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  We see things in the same way through open doors

  When the doorway gives an open view through it

  And lets us see many things outside the house.

  This vision is caused by a double stream of air.

  For first the air this side of the doorposts is seen,

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  Then follow the doorposts themselves both right and left,

  And then the light outside and the second stream

  Of light brushes the eyes, and finally

  The objects which are really seen out of doors.

  The same thing happens when a mirrored image

  Projects itself on to our sight: on its way to our eyes

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  It drives and pushes all the air between

  Itself and our eyes, and makes us feel this first

  Before we see the mirror. But when we have seen

  The mirror itself also, at once the image

  That travels from us to it and is reflected

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  Comes back to our eyes, pushing a stream of air

  In front of it, and so this first we sense

  Before we see the object in the mirror;

  That is why it appears to be so far within it.

  Wherefore again and yet again I say

  It is by no means right to be surprised

  At this appearance of objects reflected

  In the surface of a mirror, since they involve

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  A double journey with two streams of air.

  Now why is it that the right side of our body

  Appears in a mirror on the left? This is because

  When the approaching image strikes the mirror

  It is not turned round intact, but flung straight back

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  In reverse, as if someone should throw a mask

  Of plaster before it is dry against a pillar

  So that it bounces straight back keeping the features

  Set on its front, but showing them in reverse.

  In this case what was the right eye would become

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  The left, and the left eye again the right.

  An image may also pass from mirror to mirror

  So that five or six reflections are produced.


  For things can be out of sight at the back of a house

  And yet however far removed they are

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  Through twisting passages can all be brought out

  By a number of mirrors, and be seen to be inside.

  So does the image shine from mirror to mirror.

  And when the left is given it comes back right

  And then comes back again turned round to the same position.

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  Moreover, mirrors that have small sides that are curved

  In the same degree as our sides send back images

  Right to our right and unreversed. Either

  Since the image is carried across from mirror to mirror

  And then flies to us having been twice reflected,

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  Or since the image is turned round when it approaches

  As the curved shape of the mirror turns it towards us.

  Sometimes the images march along with us

  Keeping step with us and mimicking our gestures.

  This is because if you move from a part of a mirror

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  At once the images cannot return from that part.

  Nature compels all things that strike a mirror

  To be reflected back at equal angles.

  Now here is another thing: the eyes avoid

  Bright objects and refuse to gaze at them.

  The sun will blind you if you stare at it.

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  This is because its power is very great

  And from on high through the pure air the images

  Travel with great momentum and strike the eyes

  And in so doing disrupt the structure of them.

  And any strong brightness often burns the eyes

  For the reason that it contains many seeds of fire

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  Which cause pain to the eyes by piercing them.

  People with jaundice see everything yellow.

  This is because many seeds of yellow colour

  Stream from their bodies to meet the images of things;

  And many such seeds are mingled in their eyes

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  And by their contact paint everything with pallor.

  Again, we see in the dark things in the light

  Because, when the black air of darkness, being nearer,

  Has entered our eyes and taken possession of them

  There follows immediately a bright clear air

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  Which purifies them as it were and scatters

  The black shades of the first air; for this bright air

  Is made of particles much more minute

  And much more mobile and more powerful;

  As soon as this has filled the paths of the eyes

  And opened them, which previously were beset

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  By the black air, at once the images of things

  That are in the light follow and make us see them.

  But on the contrary, we cannot see

  Out of the light things that are in the dark,

  And this is why: a grosser air of darkness