PART I.

ASTRONOMY FROM PRIMITIVE TIMES UNTIL THE AGE OF DANTE.

I. APPARENT MOVEMENTS OF THE HEAVENLY BODIES AS SEEN FROM EARTH 9

II. THE BEGINNINGS OF ASTRONOMY. Gnomons and clepsydras; the constellations and the calendar; astrology and star-worship; early cosmogonies 25

III. GREEK ASTRONOMY: FIRST PERIOD. B.C. 900 to B.C. 350 1. Homeric Greece; First Notions of Astronomy 51 2. Thales and Anaximander: Earth flat, heaven a series of hemispheres 55 3. Later Flat Earth Systems: the Universe a sphere 60 4. Pythagoras and his Followers: Earth round, Earth in Motion 66

IV. GREEK ASTRONOMY: SECOND PERIOD, B.C. 400 to A.D. 150 1. Plato: the World-Soul 79 2. Eudoxus: the Spheres 88 3. Calippus: the Spheres of Eudoxus improved 93 4. Aristotle: the Philosophy of the Spheres; the three kinds of motion; Earth immoveable at the centre of the Universe; the elements; the celestial movers, and the First Mover 95 5. Aristarchus: Earth turning on her axis, and revolving round the sun 107 6. The School of Alexandria: instruments and methods; Earth’s diameter measured; the theory of Moveable Eccentrics 112 7. Hipparchus: “the Father of Astronomy;” his star catalogue; his inventions and discoveries; the precession of the equinoxes 122 8. Ptolemy: the Almagest; the system of Epicycles and Eccentrics; distance and size of the moon discovered; the stars; astrology; geography, the seven climates 134 V. RETROSPECT: Greek Cosmogonies; Greek calendar 159 VI. ASTRONOMY UNDER IMPERIAL AND CHRISTIAN ROME. B.C. 46 to A.D. 1000. Amateur Astronomers; the Julian Calendar; passion for Astrology; the Fathers; the ecclesiastical Calendar; the Schools; the Monasteries 167 VII. ARAB ASTRONOMY. A.D. 750 to 1250. Schools of Baghdad, Egypt, Spain. Improvements in Mathematics and Instruments; Ptolemy’s values more correctly determined; supposed discoveries of planetary distances and trepidation; a ninth sphere added to Ptolemy’s eight 181 VIII. THE RETURN OF GREEK ASTRONOMY TO EUROPE. A.D. 1000 to 1300. The Universities; Arab influence; Greek books; new European books; the course in Astrology in Bologna; Aristotle and the Church 199