And this is the cause why the Primum Mobile has a very swift motion; from the fervent longing which each part of that ninth heaven has to be conjoined with that Divinest Heaven, the Heaven of Rest, which is next to it, it revolves therein with so great desire, that its velocity is almost incomprehensible; and quiet and peaceful is the place of that supreme Deity, who alone doth perfectly see himself.” Of the symbolism of these Heavens he says, Convito , II 14:⁠— “As narrated above, the seven Heavens nearest to us are those of the Planets; and above these are two movable Heavens, and one motionless over all. To the first seven correspond the seven sciences of the Trivium and Quadrivium; that is, Grammar, Dialectics, Rhetoric, Arithmetic, Music, Geometry, and Astrology. To the eighth, that is, to the starry sphere, Natural Science, called Physics, corresponds, and the first science, which is called Metaphysics; and to the ninth sphere corresponds Moral Science; and to the Heaven of Rest, the Divine Science, which is called Theology.” The details of these correspondences will be given later in their appropriate places. These Ten Heavens are the heavens of the Paradiso; nine of them revolving about the earth as a central point, and the motionless Empyrean encircling and containing all.