Produced by Jonathan Ingram, Dave Maddock, Charles Franks and the Online Distributed Proofreading Team. [Illustration: SIR ISAAC NEWTON (From the bust by Roubiliac In Trinity College, Cambridge.)] HISTORY OF ASTRONOMY BY GEORGE FORBES, M.A., F.R.S., M. INST. C. E., (FORMERLY PROFESSOR OF NATURAL PHILOSOPHY, ANDERSON’S COLLEGE, GLASGOW) AUTHOR OF “THE TRANSIT OF VENUS,” RENDU’S “THEORY OF THE GLACIERS OF SAVOY,” ETC., ETC. CONTENTS PREFACE BOOK I. THE GEOMETRICAL PERIOD 1. PRIMITIVE ASTRONOMY AND ASTROLOGY 2. ANCIENT ASTRONOMY—CHINESE AND CHALDÆANS 3. ANCIENT GREEK ASTRONOMY 4. THE REIGN OF EPICYCLES—FROM PTOLEMY TO COPERNICUS BOOK II. THE DYNAMICAL PERIOD 5. DISCOVERY OF THE TRUE SOLAR SYSTEM—TYCHO BRAHE—KEPLER 6. GALILEO AND THE TELESCOPE—NOTIONS OF GRAVITY BY HORROCKS, ETC. 7. SIR ISAAC NEWTON—LAW OF UNIVERSAL GRAVITATION 8. NEWTON’S SUCCESSORS—HALLEY, EULER, LAGRANGE, LAPLACE, ETC. 9. DISCOVERY OF NEW PLANETS—HERSCHEL, PIAZZI, ADAMS, AND LE VERRIER BOOK III. OBSERVATION 10. INSTRUMENTS OF PRECISION—SIZE OF THE SOLAR SYSTEM 11. HISTORY OF THE TELESCOPE—SPECTROSCOPE BOOK IV. THE PHYSICAL PERIOD 12. THE SUN 13. THE MOON AND PLANETS 14. COMETS AND METEORS 15. THE STARS AND NEBULÆ ILLUSTRATIONS INDEX PREFACE An attempt has been made in these pages to trace the evolution of intellectual thought in the progress of astronomical discovery, and, by recognising the different points of view of the different ages, to give due credit even to the ancients. No one can expect, in a history of astronomy of limited size, to find a treatise on “practical” or on “theoretical astronomy,” nor a complete “descriptive astronomy,” and still less a book on “speculative astronomy.” Something of each of these is essential, however, for tracing the progress of thought and knowledge which it is the object of this History to describe. The progress of human knowledge is measured by the increased habit of looking at facts from new points of view, as much as by the accumulation of facts. The mental capacity of one age does not seem to differ from that of other ages; but it is the imagination of new points of view that gives a wider scope to that capacity. And this is cumulative, and therefore progressive. Aristotle viewed the solar system as a geometrical problem; Kepler and Newton converted the point of view into a dynamical one. Aristotle’s mental capacity to understand the meaning of facts or to criticise a train of reasoning may have been equal to that of Kepler or Newton, but the point of view was different.