PHYSICS

...is the end of them, and he who is closer to it in the similarity of its motion is swifter, and his power is stronger; and he who is more remote from it in the similarity of its motion is slower in motion, and his power is weaker.

And when it has been declared by us that the one closer to this sphere is swifter than the one who is more remote and more similar in motion, and the one closer to this becomes more similar to it and swifter in motion than the one who is more remote—this is because the similarity to it in velocity is not approached with the uniformity of those motions of the planets with their diversity—then we arrive at the intended goal, and we have with this the cause of their succession and order, which cannot be otherwise. For the wise men of this science—both the ancients and the moderns—differ concerning the order of these spheres, and no one has seen the efficient cause of this. Indeed, the order of them among them has been derived inductively from sense, and they have attempted to bring forward in this unnecessary causes. I suppose that this famous order found among them is that which was handed down to them from their predecessors, and because the moderns have scrutinized its cause, they have been discordant in this, as is evident in their books.

Let us return to that in which we were, saying that it is indeed also proven—what we said—that motion proceeds from the superior body, from that which is seen in this inferior world, namely the generable and corruptible the sublunary realm, subject to birth and decay existing under the heaven. For in the motive power of the world, which belongs to the body moving the universe, it appears that which we have said: for the motion of that which is closer to it is stronger and swifter than that of the one which is more remote. For the emanation of circular motion in them, which is beyond their natural motion, is from it. For in the igneous material the element of fire, we see a circular motion similar to celestial motion, in that which is seen like the stars appearing at certain times burning in the superior places at night; therefore, they seem to the observer to be stars, and they appear to move with the motion of the stars, or to follow them to the extent that they have a setting. And this indeed indicates that that element is moved, carried by the motion of the superior heaven.

The element of air, in its motion, has a certain lightness, although it does not preserve order due to the tempest in the nature of air, which is the reception of expulsion and the velocity of eruption and splitting. However, it remains in it for the most part that it is moved to the motion of the heaven, and especially at the rising of the sun and its declination after rising, and also at the setting. We indeed see [evidence] of the motion of the air and its tempest, although we are in the air and do not feel its motion. Furthermore, air close to the Earth, and existing beneath its parts from lakes and mountains—in which there is thickness due to vapors ascending from the Earth and water—its motion does not appear to the sense, whence the motion of it does not preserve order, although it is of lesser velocity than the motion of fire.

The element of water: the motion of it is plainly visible in that it follows the motion of the heaven necessarily, although its motion is not upon a complete circle. This is indeed from that which we see of the motion of the great sea during the day and night according to the same order, as if it were an equidistant motion. This indeed proceeds from its weight and from that which is in its nature from the declination downward and the deepening to the inferior places of the Earth. And fully, from that which is declared, the motion of the heaven is with it when it gathers in the sea, in which no end or boundary is apprehended except one alone because of its magnitude and depth. The motion of the water, however, which is from the east, is the motion that follows that which is superior; its motion in the return is because of its weight and declination downward from its multitude. But the motion of the water is less swift than the motion of the air, wherefore they think concerning the water that it follows in its motion the motion of the moon because of the proximity of their motions. They believed that it happens thus because they pursue it, yet they fall short of it, and the power does not arrive for it to complete the revolution; thus another revolution follows, and the completion of the revolution accelerates, whence water is in a continual tempest as it appears to them.

The Earth, however, appears to be quiescent in itself entirely, although in some of its parts there has been some...