1. The subject-matter of astronomy is made up of many kinds. For it defines what the universe is, what the heavens, what the position and movement of the sphere, what the axis of the heavens and the poles, what are the climates of the heavens, what the courses of the sun and moon and stars, and so forth. Chapter 29. On the universe and its name. 1. _Mundus_ (the universe) is that which is made up of the heavens and earth and the sea and all the heavenly bodies. And it is called _mundus_ for the reason that it is always in _motion_. For no repose is granted to its elements. Chapter 30. On the form of the universe. 1. The form of the universe is described as follows: as the universe rises toward the region of the north, so it slopes away toward the south; its head and face, as it were, is the east, and its back part the north. Chapter 31. On the heavens and their name. 1. The philosophers have asserted that the heavens are round, in rapid motion, and made of fire, and that they are called by this name (_coelum_) because they have the forms of the stars fixed on them, like a dish with figures in relief (_coelatum_). 2. For God decked them with bright lights, and filled them with the glowing circles of the sun and moon, and adorned them with the glittering images of flashing stars. Chapter 32. On the situation of the celestial sphere. 1. The sphere of the heavens is rounded and its center is the earth, equally shut in on every side. This sphere, they say, has neither beginning nor end, for the reason that being rounded like a circle it is not easily perceived where it begins or where it ends. 2. The philosophers have brought in the theory of seven heavens of the universe, that is, globes with planets moving harmoniously, and they assert that by their circles all things are bound together, and they think that these, being connected, and, as it were, fitted to one another, move backward and are borne with definite motions in contrary directions. Chapter 33. On the motion of the same. 1. The sphere revolves on two axes, of which one is the northern, which never sets, and is called Boreas; the other is the southern, which is never seen, and is called Austronotius. 2. On these two poles the sphere of heaven moves, they say, and with its motion the stars fixed in it pass from the east all the way around to the west, the _septentriones_ near the point of rest describing smaller circles. Chapter 34. On the course of the same sphere. 1. The sphere of heaven, [moving] from the east towards the west, turns once in a day and night, in the space of twenty-four hours, within which the sun completes his swift revolving course over the lands and under the earth. Chapter 35. On the swiftness of the heavens. 1. With such swiftness is the sphere of heaven said to run, that if the stars did not run against its headlong course in order to delay it, it would destroy the universe. Chapter 36. On the axis of the heavens.