CONTENTS.

INTRODUCTION 1
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]
PART II.
THE ASTRONOMY OF DANTE.
I.Popular Astronomy in Italy in Dante’s Time.
 The astronomy of Dante contrasted with Homer and Milton.
 General feeling for astronomy in his day; some famous
 astrologers: astronomy considered an ennobling study;
 Ptolemy’s system final. Knowledge of average educated man.[209]
II.Dante’s Studies.
 Dante a representative of contemporary beliefs: his erudition;
 his education; Brunetto Latini’s influence; possible visits to
 universities of Bologna, Padua, Paris.[223]
III.Books on Astronomy used by Dante.
 Dante’s wide reading; his diligence and memory. Ptolemy his
 supreme authority on astronomy; his principal text-books
 Alfraganus and Aristotle; versions used. Classical Latin authors;
 Greek; Arab; Christian[231]
IV.Astronomy in Dante’s Writings.
 References to heavenly bodies in Vita Nuova, the Canzoniere,
 Convivio, Latin works and letters, Divine Comedy. Artistic use
 of the facts and theories of astronomy.[253]
V.Observational Astronomy
 1. Movements of the Moon[261]
 2. Movements of the Sun[270]
 3. The Stars[283]
 4. The Galaxy[303]
 5. The Planets[307]
 6. Eclipses[316]
 7. Comets and Meteors[318]
 8. The Sun’s Path in the Sky seen from different Parts of the Earth[322]
 9. Celestial Phenomena and Time[338]
VI.Dante’s Journey through the Three Realms:
Indications of Time and Direction by Means of the Skies
 1. Time references in the Divine Comedy[353]
 2. The Inferno[367]
 3. Purgatory[373]
 4. Paradise[391]
 5. Positions of Sun, Moon, and Planets among the Stars during Dante’s Vision[402]
 6. The Assumed Date of the Vision[409]
VII.Theoretical and Speculative Astronomy
 1. The Spheres[429]
 2. The Spheres and the four Elements[441]
 3. Dimensions and Physical Nature of the Universe[457]
 4. Influence of the Spheres on Human Affairs[471]
 5. The Motive Power[480]
VIII.Mediæval and Modern Views of the Universe[487]