Ten Treatises on Astronomy (Book of Astronomy)

...the heat is reduced: nor does the growth of things then occur, nor any ordered generation, except for the germination of certain seeds. And that sign is called Virgo original: "virgo"; because the virgin is a humble and sterile animal, since all things tend toward diminution and a kind of sterility. Next, the sun enters Libra; because then the day is equal to the night and the heat is diminished, and an equality is created between cold and heat, because then the cold begins as if to take up its strength, and all things are in equality then. Then the sun enters Scorpio and the cold is increased over the heat, and there is now cold, now heat; and the air is dispersed and rains occur, and wicked, pestilential, and deadly diseases are generated in the manner of poison and the like; and therefore that sign is named after that poisonous animal, the scorpion. Next, the cold manifestly increases over the heat, and then the sun is said to enter Sagittarius; because then changes of the air occur and the air inclines toward the side of coldness; and there come upon us strong frosts, snows, and ice sent from the air like arrows original: "sagitte" hurting living things and plants. Then the cold is increased over the heat and the heat is as if put to sleep, and the air declines toward an immoderate and melancholy coldness; and then there occur much snow and extreme cold and ice and the like; whence, since the Capricorn is a cold, dry, and melancholy animal, that sign is named after that animal; and the sun is then in its ultimate decline from the equator toward the south. Then the sun begins to return toward the equator, and then the cold begins in a certain way to be diminished, and sometimes rains occur in place of snows, and the air is made more humid; whence that sign, Aquarius, is named from such a disposition of the air then prevailing. Then the Sun enters through Pisces, and that sign was named after the Fish, which is an aquatic animal; because then rains abound more than in other times of the year, unless perhaps by chance sometimes; and if there should then be snows or frosts or ice, they are more quickly converted into water than in other winter times.

Here begins the second part: of the second treatise on the essence of the essential circle.

Chapter One: On the division of the circle of signs into twelve signs, and of each sign into 30 degrees, and of each degree into 60 minutes, and of each minute into 60 seconds.

A square astrological chart (horoscope diagram) divided into twelve sections by intersecting diagonal and internal lines. Latin labels for the zodiac signs are written in the segments: Aquarius and Sagittarius at the top; Scorpio, Libra, and Virgo on the right; Leo, Cancer, and Gemini at the bottom; and Taurus, Aries, and Pisces on the left. The label Capricorn is placed in the top-left interior segment.

Indeed, you ought to know that the circle of signs, which is called the zodiac or zodias, is divided into twelve equal divisions, any of which is called a sign; and the signs are named, as was said above, after the likeness of certain animals which are formed according to their shapes, as I told you. Therefore, the first sign is called Aries; the second Taurus; the third Gemini; the fourth Cancer; the fifth Leo; the sixth Virgo; the seventh Libra; the eighth Scorpio; the ninth Sagittarius; the tenth Capricorn; the eleventh Aquarius; the twelfth Pisces. And each one of those signs is divided into 30 equal parts, any of which is called a degree. And each degree is divided into 60 equal parts, any of which is called a minute. And each minute is divided into 60 equal parts, any of which is called a second. And each second is divided into 60 equal parts, any of which is called a third. And each third is divided into 60 equal parts, any of which is called a fourth; and so on until the last of the numbers. But some numbers beyond these will fall to you in your work, and especially in your equations; namely, certain ones from the Order of Preachers The translator likely refers to the Dominicans here, or perhaps "predicators" in a general sense of those who declare things, though there is a subtle poke at their philosophical pretensions. who descend even unto the fifth and sixth divisions, so that they might seem to philosophize without actually philosophizing.

Chapter Two: To show which signs are Northern and which are Southern.

It has been shown above that there are twelve signs, and into how many parts each sign is divided. Now, however, it must be said which of them are Northern Septentrionalia: Signs located in the northern celestial hemisphere. and how many and which are Southern Meridionalia: Signs located in the southern celestial hemisphere.. The Northern ones are those six, namely, those which are from the beginning of Aries until the end of Virgo: specifically, Aries, Taurus, Gemini, Cancer, Leo, and Virgo. And they are called Northern because they are on the side of the North from the equator of the day. The remaining six are those which are from the beginning of Libra until the end of Pisces. And they are called Southern because they are on the side of the South from the equator of the day.

Again, it is known which signs are Northern and which are Southern. Now it must be said which signs are of Direct Ascension and which are of Tortuous Ascension Ascensio: Refers to how the signs rise over the horizon; "direct" signs take longer to rise, while "tortuous" signs rise more quickly at a sharper angle.. Those of Direct Ascension are those six, namely, those which are from the beginning of Cancer until the end of Sagittarius. And they are called of Direct Ascension because they ascend all rightly and in a longer time than their opposites. The remaining six, namely, those from the beginning of Capricorn until the end of Gemini, are called of Tortuous Ascension because they do not ascend as directly as their aforementioned opposites. And they are called "tortuously ascending" because they ascend crookedly and in a shorter time than their aforementioned opposites, which are Capricorn, Aquarius, Pisces, Aries...