Chapter XXXIV: Book III: , Chapter 24. On the name of astronomy

1. Astronomy is the law of the stars, and it traces with inquiring reason the courses of the heavenly bodies, and their figures, and the regular movements of the stars with reference to one another and to the earth.

Chapter 25. On its discoverers.

1. The Egyptians were the first to discover astronomy. And the Chaldeans first taught astrology and the observance of nativity. Moreover, Josephus asserts that Abraham taught astrology to the Egyptians. The Greeks, however, say that this art was first elaborated by Atlas, and therefore it was said that he held the heavens up.

2. Whoever was the discoverer, it was the movement of the heavens and his rational faculty that stirred him, and in the light of the succession of seasons, the observed and established courses of the stars, and the regularity of the intervals, he considered carefully certain dimensions and numbers, and getting a definite and distinct idea of them he wove them into order and discovered astrology.

Chapter 26. On its teachers.

1. In both Greek and Latin there are volumes written on astronomy by different writers. Of these Ptolemy[268] is considered chief among the Greeks. He also taught rules by which the courses of the stars may be discovered.[269]

[268] Du Breul has _Ptolemaeus, rex Alexandriae_.

[269] The canons by which Ptolemy calculated the position of the
planets. Isidore makes no further reference to them.

Chapter 27. The difference between astronomy and astrology.

1. There is some difference between astronomy and astrology. For astronomy embraces the revolution of the heavens, the rise, setting, and motion of the heavenly bodies, and the origin of their names. Astrology, on the other hand, is in part natural, in part superstitious.

2. It is natural astrology when it describes the courses of the sun and the moon and the stars, and the regular succession of the seasons. Superstitious astrology is that which the mathematici follow, who prophesy by the stars, and who distribute the twelve signs of the heavens among the individual parts of the soul or body, and endeavor to predict the nativities and characters of men from the course of the stars.