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Book II, Chapter 6. Of the Nature of the Stars and the Motion of the Planets.
Let us return from this digression to the other parts of nature. The stars which are described as fixed in the heavens, are not, as the vulgar suppose, attached each of them to different individuals, the brighter to the rich, those that are less so to the poor, and the dim to the aged, shining according to the lot of the individual, and separately assigned to mortals; for they have neither come into existence, nor do they perish in connexion with particular persons, nor does a falling star indicate that any one is dead. We are not so closely connected with the heavens as that the shining of the stars is affected by our death. When they are supposed to shoot or fall, they throw out, by the force of their fire, as if from an excess of nutriment, the superabundance of the humour which they have absorbed, as we observe to take place from the oil in our lamps, when they are burning. The nature of the celestial bodies is eternal, being interwoven, as it were, with the world, and, by this union, rendering it solid; but they exert their most powerful influence on the earth. This, notwithstanding its subtilty, may be known by the clearness and the magnitude of the effect, as we shall point out in the proper place. The account of the circles of the heavens will be better understood when we come to speak of the earth, since they have all a reference to it; except what has been discovered respecting the Zodiac, which I shall now detail.
Anaximander the Milesian, in the 58th olympiad, is said to have been the first who understood its obliquity, and thus opened the road to a correct knowledge of the subject. Afterwards Cleostratus made the signs in it, first marking those of Aries and Sagittarius; Atlas had formed the sphere long before this time. But now, leaving the further consideration of this subject, we must treat of the bodies that are situated between the earth and the heavens.
It is certain that the star called Saturn is the highest, and therefore appears the smallest, that he passes through the largest circuit, and that he is at least thirty years in completing it. The course of all the planets, and among others of the Sun, and the Moon, is in the contrary direction to that of the heavens, that is towards the left, while the heavens are rapidly carried about to the right. And although, by the stars constantly revolving with immense velocity, they are raised up, and hurried on to the part where they set, yet they are all forced, by a motion of their own, in an opposite direction; and this is so ordered, lest the air, being always moved in the same direction, by the constant whirling of the heavens, should accumulate into one mass, whereas now it is divided and separated and beaten into small pieces, by the opposite motion of the different stars. Saturn is a star of a cold and rigid nature, while the orbit of Jupiter is much lower, and is carried round in twelve years. The next star, Mars, which some persons call Hercules, is of a fiery and burning nature, and from its nearness to the sun is carried round in little less than two years. In consequence of the excessive heat of this star and the rigidity of Saturn, Jupiter, which is interposed between the two, is tempered by both of them, and is thus rendered salutary. The path of the Sun consists of 360 degrees; but, in order that the shadow may return to the same point of the dial, we are obliged to add, in each year, five days and the fourth part of a day. On this account an intercalary day is given to every fifth year, that the period of the seasons may agree with that of the Sun.
Below the Sun revolves the great star called Venus, wandering with an alternate motion, and, even in its surnames, rivalling the Sun and the Moon. For when it precedes the day and rises in the morning, it receives the name of Lucifer, as if it were another sun, hastening on the day. On the contrary, when it shines in the west, it is named Vesper, as prolonging the light, and performing the office of the moon. Pythagoras, the Samian, was the first who discovered its nature, about the 62nd olympiad, in the 222nd year of the City. It excels all the other stars in size, and its brilliancy is so considerable, that it is the only star which produces a shadow by its rays. There has, consequently, been great interest made for its name; some have called it the star of Juno, others of Isis, and others of the Mother of the Gods. By its influence everything in the earth is generated. For, as it rises in either direction, it sprinkles everything with its genial dew, and not only matures the productions of the earth, but stimulates all living things. It completes the circuit of the Zodiac in 348 days, never receding from the sun more than 46 degrees, according to Timæus.
Similarly circumstanced, but by no means equal in size and in power, next to it, is the star Mercury, by some called Apollo; it is carried in a lower orbit, and moves in a course which is quicker by nine days, shining sometimes before the rising of the sun, and at other times after its setting, but never going farther from it than 23 degrees, as we learn from Timæus and Sosigenes. The nature of these two stars is peculiar, and is not the same with those mentioned above, for those are seen to recede from the sun through one-third or one-fourth part of the heavens, and are often seen opposite to it. They have also other larger circuits, in which they make their complete revolutions, as will be described in the account of the great year.
But the Moon, which is the last of the stars, and the one the most connected with the earth, the remedy provided by nature for darkness, excels all the others in its admirable qualities. By the variety of appearances which it assumes, it puzzles the observers, mortified that they should be the most ignorant concerning that star which is the nearest to them. She is always either waxing or waning; sometimes her disc is curved into horns, sometimes it is divided into two equal portions, and at other times it is swelled out into a full orb; sometimes she appears spotted and suddenly becomes very bright; she appears very large with her full orb and suddenly becomes invisible; now continuing during all the night, now rising late, and now aiding the light of the sun during a part of the day; becoming eclipsed and yet being visible while she is eclipsed; concealing herself at the end of the month and yet not supposed to be eclipsed. Sometimes she is low down, sometimes she is high up, and that not according to one uniform course, being at one time raised up to the heavens, at other times almost contiguous to the mountains; now elevated in the north, now depressed in the south; all which circumstances having been noticed by Endymion, a report was spread about, that he was in love with the moon. We are not indeed sufficiently grateful to those, who, with so much labour and care, have enlightened us with this light; while, so diseased is the human mind, that we take pleasure in writing the annals of blood and slaughter, in order that the crimes of men may be made known to those who are ignorant of the constitution of the world itself.
Being nearest to the axis, and therefore having the smallest orbit, the Moon passes in twenty-seven days and the one-third part of a day, through the same space for which Saturn, the highest of the planets, as was stated above, requires thirty years. After remaining for two days in conjunction with the sun, on the thirtieth day she again very slowly emerges to pursue her accustomed course. I know not whether she ought not to be considered as our instructress in everything that can be known respecting the heavens; as that the year is divided into the twelve divisions of the months, since she follows the sun for the same number of times, until he returns to the commencement of his course; and that her brightness, as well as that of the other stars, is regulated by that of the sun, if indeed they all of them shine by light borrowed from him, such as we see floating about, when it is reflected from the surface of water. On this account it is that she dissolves so much moisture, by a gentle and less perfect force, and adds to the quantity of that which the rays of the sun consume. On this account she appears with an unequal light, because being full only when she is in opposition, on all the remaining days she shows only so much of herself to the earth as she receives light from the sun. She is not seen in conjunction, because, at that time, she sends back the whole stream of light to the source whence she has derived it. That the stars generally are nourished by the terrestrial moisture is evident, because, when the moon is only half visible she is sometimes seen spotted, her power of absorbing moisture not having been powerful enough; for the spots are nothing else than the dregs of the earth drawn up along with the moisture. But her eclipses and those of the sun, the most wonderful of all the phenomena of nature, and which are like prodigies, serve to indicate the magnitude of these bodies and the shadow which they cast.
To prove your understanding of this lesson, draw a diagram that illustrates Pliny’s description of the earth, sun, moon, stars and planets.