The Sphere of the World

Symbols of the planets

¶ Furthermore, according to an accidental property, the sphere is divided into the right sphere and the oblique sphere. Those are said to have a right sphere A "right sphere" refers to the celestial orientation for an observer at the equator, where the celestial poles lie on the horizon and the stars rise and set vertically. who live beneath the equinoctial line The celestial equator; the imaginary line in the sky directly above the Earth's equator., if indeed anyone is able to live there. It is called "right" because neither of the poles is raised higher than the other for those observers. Or, it is so called because their horizon intersects the equinoctial line and is intersected by it at right spherical angles. However, those are said to have an oblique sphere who live anywhere around the equinoctial line or beyond it. For them, one of the poles is always raised above the horizon, while the other is always depressed below it. Or, it is so called because their artificial horizon intersects the equinoctial line and is intersected by it at unequal and oblique angles.

What the form of the world is.

¶ The universal machine of the world is divided into two parts: namely, the ethereal and the elementary regions. The elementary region, being constantly subject to change In Aristotelian physics, the "sublunary" or elementary region is the only place where things are born, die, and change., is divided into four parts. For the earth is situated in the middle of all things as the center of the world; around it is water; around the water is air; and around the air is fire—there pure and undisturbed—reaching to the sphere of the moon, as Aristotle says in his book On Meteorology original: "methaurorum". For so did God, glorious and sublime, dispose these things. And these are called the four elements, which in turn are changed, corrupted, and regenerated by one another. The elements are simple bodies which cannot be divided into parts of different forms, and from their mixing together, the various species of generated things are created. Any of the three air, water, and fire surrounds the earth in a circular fashion on all sides, except in so far as the dryness of the earth resists the moisture of the water to preserve the life of living creatures. All these things, except the earth, are in motion. The earth, as the center of the world, by its own weight equally fleeing the great motion of the outer edges from every direction, occupies the middle of the round sphere.

¶ Around the elementary region, the ethereal region—luminous and immune from all variation due to its immutable essence—moves in a continuous circular motion; and this is called by the philosophers the "fifth essence" quintessence; the celestial substance believed to be fundamentally different from the four earthly elements. There are nine spheres within it, as was just discussed: namely, those of the Moon, ☿ Mercury, ♀ Venus, the Sun, ♂ Mars, Jupiter, Saturn, and the Stars...