Bodies that strike the eyes, awaking sight. 
From certain things flow odours evermore, 
As cold from rivers, heat from sun, and spray 
From waves of ocean, eater-out of walls 
Around the coasts. Nor ever cease to flit 
The varied voices, sounds athrough the air. 
Then too there comes into the mouth at times 
The wet of a salt taste, when by the sea 
We roam about; and so, whene'er we watch 
The wormword being mixed, its bitter stings. 
To such degree from all things is each thing 
Borne streamingly along, and sent about 
To every region round; and Nature grants 
Nor rest nor respite of the onward flow, 
Since 'tis incessantly we feeling have, 
And all the time are suffered to descry 
And smell all things at hand, and hear them sound. 
Besides, since shape examined by our hands 
Within the dark is known to be the same 
As that by eyes perceived within the light 
And lustrous day, both touch and sight must be 
By one like cause aroused. So, if we test 
A square and get its stimulus on us 
Within the dark, within the light what square 
Can fall upon our sight, except a square 
That images the things? Wherefore it seems 
The source of seeing is in images, 
Nor without these can anything be viewed. 

Now these same films I name are borne about 
And tossed and scattered into regions all. 
But since we do perceive alone through eyes, 
It follows hence that whitherso we turn 
Our sight, all things do strike against it there 
With form and hue. And just how far from us 
Each thing may be away, the image yields 
To us the power to see and chance to tell: 
For when 'tis sent, at once it shoves ahead 
And drives along the air that's in the space 
Betwixt it and our eyes. And thus this air 
All glides athrough our eyeballs, and, as 'twere, 
Brushes athrough our pupils and thuswise 
Passes across. Therefore it comes we see 
How far from us each thing may be away, 
And the more air there be that's driven before, 
And too the longer be the brushing breeze 
Against our eyes, the farther off removed 
Each thing is seen to be: forsooth, this work 
With mightily swift order all goes on, 
So that upon one instant we may see 
What kind the object and how far away. 

Nor over-marvellous must this be deemed 
In these affairs that, though the films which strike 
Upon the eyes cannot be singly seen, 
The things themselves may be perceived. For thus 
When the wind beats upon us stroke by stroke 
And when the sharp cold streams, 'tis not our wont 
To feel each private particle of wind 
Or of that cold, but rather all at once; 
And so we see how blows affect our body, 
As if one thing were beating on the same 
And giving us the feel of its own body 
Outside of us. Again, whene'er we thump 
With finger-tip upon a stone, we touch 
But the rock's surface and the outer hue, 
Nor feel that hue by contact- rather feel 
The very hardness deep within the rock. 

Now come, and why beyond a looking-glass 
An image may be seen, perceive. For seen 
It soothly is, removed far within. 
'Tis the same sort as objects peered upon 
Outside in their true shape, whene'er a door 
Yields through itself an open peering-place, 
And lets us see so many things outside 
Beyond the house. Also that sight is made 
By a twofold twin air: for first is seen 
The air inside the door-posts; next the doors, 
The twain to left and right; and afterwards 
A light beyond comes brushing through our eyes, 
Then other air, then objects peered upon 
Outside in their true shape. And thus, when first 
The image of the glass projects itself, 
As to our gaze it comes, it shoves ahead 
And drives along the air that's in the space 
Betwixt it and our eyes, and brings to pass 
That we perceive the air ere yet the glass. 
But when we've also seen the glass itself, 
Forthwith that image which from us is borne 
Reaches the glass, and there thrown back again 
Comes back unto our eyes, and driving rolls 
Ahead of itself another air, that then 
'Tis this we see before itself, and thus 
It looks so far removed behind the glass. 
Wherefore again, again, there's naught for wonder 

In those which render from the mirror's plane 
A vision back, since each thing comes to pass 
By means of the two airs. Now, in the glass 
The right part of our members is observed 
Upon the left, because, when comes the image 
Hitting against the level of the glass, 
'Tis not returned unshifted; but forced off 
Backwards in line direct and not oblique,- 
Exactly as whoso his plaster-mask 
Should dash, before 'twere dry, on post or beam, 
And it should straightway keep, at clinging there, 
Its shape, reversed, facing him who threw, 
And so remould the features it gives back: 
It comes that n