nov I will tell thee the true cause of the variety in the
surface of the moon.

"Within the heaven of the divine peace revolves a body, in whose
virtue lies the being of all that it contains.[1] The following
heaven[2] which has so many sights, distributes that being
through divers essences[3] from it distinct, and by it
contained. The other spheres, by various differences, dispose the
distinctions which they have within themselves unto their ends
and their seeds.[4] These organs of the world thus proceed, as
thou now seest, from grade to grade; for they receivefrom above,
and operate below. Observe me well, how I advance through this
place to the truth which thou desirest, so that hereafter thou
mayest know to keep the ford alone. The motion and the virtue of
the holy spheres must needs be inspired by blessed motors, as the
work of the hammer by the smith. And the heaven, which so many
lights make beautiful, takes its image from the deep Mind which
revolves it, and makes thereof a seal. And as the soul within
your dust is diffused through different members, and conformed to
divers potencies, so the Intelligence[5] displays its own
goodness multiplied through the stars, itself circling upon its
own unity. Divers virtue makes divers alloy with the precious
body that it quickens, in which, even as life in you, it is
bound. Because of the glad nature whence, it flows, the virtue
mingled through the body shines,[6] as gladness through the
living pupil. From this,[7] comes whatso seems different between
light and light, not from dense and rare; this is the formal
principle which produces, conformed unto its goodness, the dark
and the bright."