so small
That even their third part can nowise be seen;
Judge, then, the size of any inward organ--
What of their sphered heart, their eyes, their limbs,
The skeleton?--How tiny thus they are!
And what besides of those first particles
Whence soul and mind must fashioned be?--Seest not
How nice and how minute? Besides, whatever
Exhales from out its body a sharp smell--
The nauseous absinth, or the panacea,
Strong southernwood, or bitter centaury--
If never so lightly with thy [fingers] twain
Perchance [thou touch] a one of them

*****

Then why not rather know that images
Flit hither and thither, many, in many modes,
Bodiless and invisible?

But lest
Haply thou holdest that those images
Which come from objects are the sole that flit,
Others indeed there be of own accord
Begot, self-formed in earth's aery skies,
Which, moulded to innumerable shapes,
Are borne aloft, and, fluid as they are,
Cease not to change appearance and to turn
Into new outlines of all sorts of forms;
As we behold the clouds grow thick on high
And smirch the serene vision of the world,
Stroking the air with motions. For oft are seen
The giants' faces flying far along
And trailing a spread of shadow; and at times
The mighty mountains and mountain-sundered rocks
Going before and crossing on the sun,
Whereafter a monstrous beast dragging amain
And leading in the other thunderheads.
Now [hear] how easy and how swift they be
Engendered, and perpetually flow off
From things and gliding pass away....

*****

For ever every outside streams away
From off all objects, since discharge they may;
And when this outside reaches other things,
As chiefly glass, it passes through; but where
It reaches the rough rocks or stuff of wood,
There 'tis so rent that it cannot give back
An image. But when gleaming objects dense,
As chiefly mirrors, have been set before it,
Nothing of this sort happens. For it can't
Go, as through glass, nor yet be rent--its safety,
By virtue of that smoothness, being sure.
'Tis therefore that from them the images
Stream back to us; and howso suddenly
Thou place, at any instant, anything
Before a mirror, there an image shows;