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,