But if this rarity go not through and through, There needs must be a limit, beyond which Its contrary prevents the further passing,
And thence the foreign radiance is reflected, Even as a colour cometh back from glass, The which behind itself concealeth lead.
Now thou wilt say the sunbeam shows itself More dimly there than in the other parts, By being there reflected farther back.
From this reply experiment will free thee If e’er thou try it, which is wont to be The fountain to the rivers of your arts.
Three mirrors shalt thou take, and two remove Alike from thee, the other more remote Between the former two shall meet thine eyes.
Turned towards these, cause that behind thy back Be placed a light, illuming the three mirrors And coming back to thee by all reflected.
Though in its quantity be not so ample The image most remote, there shalt thou see How it perforce is equally resplendent.
Now, as beneath the touches of warm rays Naked the subject of the snow remains Both of its former colour and its cold,
Thee thus remaining in thy intellect, Will I inform with such a living light, That it shall tremble in its aspect to thee.
Within the heaven of the divine repose Revolves a body, in whose virtue lies The being of whatever it contains.
The following heaven, that has so many eyes, Divides this being by essences diverse, Distinguished from it, and by it contained.
The other spheres, by various differences, All the distinctions which they have within them Dispose unto their ends and their effects.
Thus do these organs of the world proceed, As thou perceivest now, from grade to grade; Since from above they take, and act beneath.
Observe me well, how through this place I come Unto the truth thou wishest, that hereafter Thou mayst alone know how to keep the ford
The power and motion of the holy spheres, As from the artisan the hammer’s craft, Forth from the blessed motors must proceed.
The heaven, which lights so manifold make fair, From the Intelligence profound, which turns it, The image takes, and makes of it a seal.
And even as the soul within your dust Through members different and accommodated To faculties diverse expands itself,
So likewise this Intelligence diffuses Its virtue multiplied among the stars. Itself revolving on its unity.
Virtue diverse doth a diverse alloyage Make with the precious body that it quickens, In which, as life in you, it is combined.
From the glad nature whence it is derived, The mingled virtue through the body shines, Even as gladness through the living pupil.
From this proceeds whate’er from light to light Appeareth different, not from dense and rare: This is the formal principle that produces,
According to its goodness, dark and bright.”
Paradiso: Canto III
That Sun, which erst with love my bosom warmed, Of beauteous truth had unto me discovered, By proving and reproving, the sweet aspect.
And, that I might confess myself convinced And confident, so far as was befitting, I lifted more erect my head to speak.
But there appeared a vision, which withdrew me So close to it, in order to be seen, That my confession I remembered not.
Such as through polished and transparent glass, Or waters crystalline and undisturbed, But not so deep as that their bed be lost,
Come back again the outlines of our faces So feeble, that a pearl on forehead white Comes not less speedily unto our eyes;
Divine Comedy, Longfellow's Translation, Paradise · The Wunder Library — complete classics, free to read, with narration.