Chapter 14: On the Apses of the Planets

Each of the planets has its own circle among the stars, which the Greeks called an apse; these circles are different from those of the world, for the centre of the world or heaven is the earth which lies between the two peaks or poles, and it is also the centre of the Zodiac, which is inclined between these poles. All this is known and, having been drawn with a compass, becomes quite obvious. The lpsids of the planets have some other center, so the circles [they describe] are different, and they move in different ways. Since the lower [halves of each] apse should be shorter, and the highest [positions of each planet] relative to the center of the earth are as follows: Saturn in Scorpio, Jupiter in Virgo, Mars in Leo, the Sun in Gemini, Venus in Sagittarius, Mercury in Capricorn, the Moon in Taurus, and accordingly the other halves [of the orbits of each planet] are on the contrary the lowest and closest to the center of the earth, so it seems to us that that [the planets] move more slowly when they are in the upper [half] of their revolution. [In fact] their natural motion, which is definite and different from the others, does not accelerate or decelerate, but since the lines drawn from the circumference of the apse to the center approach like radii in a circle, the same motion appears to us now faster and sometimes slower, according to the proximity [of the planet] to the center. Their motion quickens when they are near the earth, and slows down when they rise higher, which is best observed in the motion of the moon.

Chapter 15. Why do they change color?

Each planet has its own color: Saturn is white, Jupiter is clear, Mars is fiery, Lucifer is joyful, Vesper [21] is brilliant, Mercury is radiant; the moon has an insinuating color, the sun when it rises is blazing. However, their colors change according to the altitude, so that [the planet] becomes similar to the one in whose region it has fallen, and all approaching the alien orbit are colored in [alien] color; [approaching] a colder one into pale, a hotter one into a red one, a windy one into a shimmering one; but approaching the sun, or the intersections of the apses, or the extreme points of the orbit, [the planets are covered] with black darkness. [148]

Chapter 19. On the motion and magnitude of the Sun

It is said that the solar fire is nourished by water, and that the sun is much larger than the moon, and since the moon is also larger than the earth, [the sun is so huge that, regardless of the point of observation] appears to everyone to be of the same magnitude. As for the fact that it does not appear to us to be larger than a cubit, this is due to its extreme height and distance. However, at sunrise it appears large in India, and in Britain it is greater at sunset. Having a fiery nature, it increases its heat even more, becoming incandescent in too rapid a movement. The course of the sun divides [time] into days, months, seasons, and years, and as it approaches the earth and recedes, it distributes the temperature of the air according to the seasons, for if it remained in the same places all the time, the other places would be destroyed either by cold or heat.

Chapter 20. About the nature and location of the Moon

It is said that the moon does not decrease or grow, but, being illuminated by the sun on one side and gradually moving away from it, then approaching it, turns to us now with the light side, now with the dark side. On the day of the new moon, when the moon begins to rise, we see it lying on its back face up, because it is above the sun [and illuminated] from below; at this time it sinks to the north; during waning, it stands vertically and inclines to the south; the full moon is always opposite the sun. The moon is always [standing] high when the sun is low, and low when the sun is high, and [the luminous part of it] increases from the second day... until it becomes full, and then it decreases, after which it is not visible for 13 parts, [i.e., degrees], because of the sun. The young Moon always appears, whether at night or during the day, in the constellation of Aries. If, when rising, it was located vertically, then, when rising in the morning, it will seem to face upwards. If, on the contrary, when it rises, it seems to be turned upwards like a ship, then in the morning at sunrise it will be seen in an upright position. Thus, it has three positions and can be seen sometimes turned up, sometimes downward, sometimes standing upright.

Chapter 25. About air

Air is everything that, being like emptiness, exudes a life-giving spirit, in which birds and clouds fly and storms [rush by]. Here also the air forces, overthrown from the highest throne, are tormented by the expectation of the day of judgment, when they will be most severely condemned. Appearing to people, they dress aerial bodies corresponding to the dignity of each. And over the Moon, whose orbit serves as the boundary between air and ether, purity and eternal light reign, and it is said that not far from here is the vership of Olympus. But we see the stars in the darkness at night, the reflections [of this light]. The upper and clear air belongs to heaven, and the lower air, which becomes coarse and corporeal from moist vapors, belongs to the earth: for it is here that fire, hail, snow, ice, and thunderstorms are commanded, which are commanded to praise the Lord on earth. But sometimes this [earthly] air is also called heaven: for example, Peter says that the heavens perished during the flood, because the air was tossed up by the whirlwinds, swirling into whirlpools of waves. And the heavens of heavens are called the starry heavens — [in contrast to] these airy heavens, as higher than the lower.

Chapter 26. About the winds

Wind is the air set in motion, as can be easily seen with a small fan. And it is explained only as a stream of air, which, according to Clement, rushes down from some of the highest mountains, compressed and constrained, according to divine determination; [this stream] forms the winds, which are supposed to agitate the sea and soften the heat. The winds received different names in different parts of the sky. [149]

Chapter 28. About thunder

It is said that thunder comes from the rupture of clouds: the winds, once within them, turn there from side to side due to the mobility of their nature, seeking everywhere a way out and trying to break out; when they break free, they make a terrible noise and crack, like four horses jumping out of a stable, or a bubble, which, although small, makes a very loud sound when it bursts.