class="right">85

Chapter V. The Church and the New Astronomy: Conclusion 95 Appendices: Translations by the writer. A. Ptolemy: Almagest. Bk. I, chap. 7: That the earth has no movement of rotation 107 B. Copernicus: De Revolutionibus, Dedication to the Pope 109 C. Bodin: Universæ Naturæ Theatrum, Bk. V, sections 1 and 2 in part, and section 10 entire 115 D. Fienus: Epistolica Quæstio: Is it true that the heavens are moved and the earth is at rest? 124 Bibliography 130 Index 145

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ILLUSTRATIONS

Facsimile of the frontispiece "The Systems of the World" in Riccioli: Almagestum Novum, 1651	Frontispiece
Photographic facsimile (reduced) of a page from a copy of Copernicus: De Revolutionibus, as "corrected" in the 17th century according to the directions of the Congregations of the Index in 1620	p. 61
Photographic facsimile (reduced) of another "corrected" page from the same copy	p. 113

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PREFACE

THIS study does not belong in the field of astronomy, but in that of the history of thought; for it is an endeavor to trace the changes in people's beliefs and conceptions in regard to the universe as these were wrought by the dissolution of superstition resulting from the scientific and rationalist movements. The opening chapter is intended to do no more than to review briefly the astronomical theories up to the age of Copernicus, in order to provide a background for the better comprehension of the work of Copernicus and its effects.

Such a study has been rendered possible only by the generous loan of rare books by Professor Herbert D. Foster of Dartmouth College, Professor Edwin E. Slosson of Columbia University, Doctor George A. Plimpton and Major George Haven Putnam, both of New York, and especially by the kindly generosity of Professor David Eugene Smith of Teachers College who placed his unique collection of rare mathematical books at the writer's disposal and gave her many valuable suggestions as to available material. Professors James T. Shotwell and Harold Jacoby of Columbia University have read parts of this study in manuscript. The writer gratefully acknowledges her indebtedness not only to these gentlemen, but to the many others, librarians and their assistants, fellow-students and friends, too numerous to mention individually, whose ready interest and whose suggestions have been of real service, and above all to Professor James Harvey Robinson at whose suggestion and under whose guidance the work was undertaken, and to the Reverend Doctor Henry A. Stimson whose advice and criticism have been an unfailing source of help and encouragement.

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PART ONE

AN HISTORICAL SKETCH OF THE HELIOCENTRIC
THEORY OF THE UNIVERSE.

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CHAPTER I.

The Development of Astronomical Thought to 1400 A.D.

A Preliminary Sketch of Early Theories as a Background.

THE appearances in the heavens have from earliest historic ages filled men with wonder and awe; then they gradually became a source of questioning, and thinkers sought for explanations of the daily and nightly phenomena of sun, moon and stars. Scientific astronomy, however, was an impossibility until an exact system of chronology was devised.[1] Meanwhile men puzzled over the shape of the earth, its position in the universe, what the stars were and why the positions of some shifted, and what those fiery comets were that now and again appeared and struck terror to their hearts.

In answer to such questions, the Chaldean thinkers, slightly before the rise of the Greek schools of philosophy, developed the idea of the seven heavens in their crystalline spheres encircling the earth as their center.[2] This conception seems to lie back of both the later Egyptian and Hebraic cosmologies, as well as of the Ptolemaic. Through the visits of Greek philosophers to Egyptian shores