Aristotle gives the first place to the aether, as that which is impassible, it being a kind of a fifth body after which he placeth those that are passible, fire, air, and water, and last of all the earth.

To those bodies that are accounted celestial he assigns a motion that is circular, but to those that are seated under them, if they be light bodies, an ascending, if heavy, a descending motion.
Empedocles, that the places of the elements are not always fixed and determined, but they all succeed one another in their respective stations..