Because that denser darkling air behind
Followeth in, and fills each aperture
And thus blockades the pathways of the eyes
That there no images of any things
Can be thrown in and agitate the eyes.
And when from far away we do behold
The squared towers of a city, oft
Rounded they seem,--on this account because
Each distant angle is perceived obtuse,
Or rather it is not perceived at all;
And perishes its blow nor to our gaze
Arrives its stroke, since through such length of air
Are borne along the idols that the air
Makes blunt the idol of the angle's point
By numerous collidings. When thuswise
The angles of the tower each and all
Have quite escaped the sense, the stones appear
As rubbed and rounded on a turner's wheel--
Yet not like objects near and truly round,
But with a semblance to them, shadowily.
Likewise, our shadow in the sun appears
To move along and follow our own steps
And imitate our carriage--if thou thinkest
Air that is thus bereft of light can walk,
Following the gait and motion of mankind.