An element is that primary out of which the generated things are generated, and that in which they are ultimately resolved.[1] Indeed, the [sc. four] elements are together the unqualified substance, the matter. Fire is hot, water moist, air cold, earth dry. However, there is still the same part in the air;[2] so fire, which indeed is called “ether” and where the first sphere of fixed [stars] is produced, is the highest. Then, [it is] the [sphere] of the planets, after which [comes] air; then water. But as foundation of all things [there is] earth, being in the middle of all of them.