CHAPTER III.. The Middle Ages (from About 600 a.d. to About

THE MIDDLE AGES (FROM ABOUT 600 A.D. TO ABOUT 1500 A.D.), §§ 55-69 76-91

§ 55. The slow development of astronomy during this period 76

§ 56. =The East.= The formation of an astronomical school at the court of the Caliphs: revival of astrology: translations from the Greek by Honein ben Ishak, Ishak ben Honein, Tabit ben Korra, and others 76

§§ 57-8. The Bagdad observatory. Measurement of the earth. Corrections of the astronomical data of the Greeks: trepidation 78

§ 59. Albategnius: discovery of the motion of the sun’s apogee 79

§ 60. Abul Wafa: supposed discovery of the variation of the moon. Ibn Yunos: the Hakemite Tables 79

§ 61. Development of astronomy in the Mahometan dominions in Morocco and Spain: Arzachel: the Toletan Tables 80

§ 62. Nassir Eddin and his school: Ilkhanic Tables: more accurate value of precession 81

§ 63. Tartar astronomy: Ulugh Begh: his star catalogue 82

§ 64. Estimate of oriental astronomy of this period: Arabic numerals: survivals of Arabic names of stars and astronomical terms: nadir 82

§ 65. =The West.= General stagnation after the fall of the Roman Empire: Bede. Revival of learning at the court of Charlemagne: Alcuin 83

§ 66. Influence of Mahometan learning: Gerbert: translations from the Arabic: Plato of Tivoli, Athelard of Bath, Gherardo of Cremona. Alfonso X. and his school: the Alfonsine Tables and the Libros del Saber 84

§ 67. The schoolmen of the thirteenth century, Albertus Magnus, Cecco d’Ascoli, Roger Bacon. Sacrobosco’s Sphaera Mundi 85

§ 68. Purbach and Regiomontanus: influence of the original Greek authors: the Nürnberg school: Walther: employment of printing: conflict between the views of Aristotle and of Ptolemy: the celestial spheres of the Middle Ages: the firmament and the primum mobile 86

§ 69. Lionardo da Vinci: earthshine. Fracastor and Apian: observations of comets. Nonius. Fernel’s measurement of the earth 90