I declare truly, as I declared in the beginning, that light bodies are the bodies that move from the centre to the surrounding circle, and that heavy bodies are the bodies that move from that to the centre, and that the four elements and everything that is composed of them have these two direct motions. Consequently, since the firmament does not move from the centre, or to the centre,82 let it be understood that it is neither heavy nor light; because if it were heavy, it would move to the centre; and if it were light, it would move from the centre, and since we understand it to be neither one nor the other, we must assume it to be neither hot nor cold, because it is in hot bodies like fire that lightness is, and since that is not light, as we proved, there cannot be heat in it; and since it is in heavy bodies like the earth cold is, since the firmament is not heavy, there cannot he cold in it. Let it be understood again from that that the firmament is neither wet nor dry, because wetness causes slowness in the body in which it is, as it does in air, which moves from the centre, and in water, which moves to the centre. Thus dryness effects velocity in the bodies in which it is, as it does in fire which moves from the centre, and in earth which moves to the centre. Since there is neither swiftness nor slowness in the
There are some ignorant men who are uninformed as regards the works of God, who say that the firmament was composed from the four elements, which is clearly contrary to truth, for since the four elements possess a nature different in everything from the nature of the firmament, reason can not admit that the firmament could be composed of these. Because, as I said before, it is the nature of the four elements, that some of them move towards the centre, and others out from the centre, and that that motion occurs at regular intervals, and is slower at the end than at the beginning, and that they (the elements) are permanent in their own places, and that they never leave those places except by force, for each of the four elements is equal to the other as regards length of existence and natural permanence.
Besides, the four elements possess various properties; heat and cold, wetness and dryness, lightness and heaviness, swiftness and slowness, and the nature of the firmament is directly opposed to those natures; because in opposition to the vertical motion of the four elements, there is the circular motion of the firmament, and in opposition to the periodical occurrence of that motion, is the perpetuity in the motion of the firmament, and in opposition to the swiftness and tardiness of that motion, is the perpetual slowness in the motion of the firmament. In opposition to that lasting permanency of the four elements, in their own positions, is the permanent natural motion of the firmament in its own position. And as the four elements and their state of permanency are of equal antiquity, in the same way, the firmament and its motion are of equal antiquity, and is without any of these properties of the four elements, for there is neither heat nor cold, wetness or dryness in it, nor lightness or heaviness, nor swiftness nor slowness.
As the parts of the four elements are made, they never become corrupted nor changed but (are) as they were from the beginning of the world, firm, compact, indestructible, indissoluble, and thus they will be until the end which the Creator ordered for them. Consequently, since the nature of the four elements and the nature of the firmament are directly opposed to each other, it is against reason to say that the firmament was composed of the four elements.
Another reason against the same theory: Every object that is compounded from contrary elements that work against each other and corrupting each other, the whole corrupts in the end; such includes mankind and animals, and everything else that is composed of the four elements in which the opposite properties of the four elements destroy each other. And when one property prevails over the other, the thing that is composed of them is completely destroyed. Consequently, if the firmament were composed of the four elements, owing to those opposite qualities being mutually destructive, in the end the firmament would be dissolved and would perish.
Thus since no sign of the dissolution is, has been, or will be, observed, let it be understood that it (the firmament) is far from being composed of the four elements. Thus may He who ordered it in such wise be blessed by everyone who would behold it.