History of Astronomy   By: George Forbes (1849-1936)

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

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.

Then, again, new points of view are provided by the invention of new methods in that system of logic which we call mathematics. All that mathematics can do is to assure us that a statement A is equivalent to statements B, C, D, or is one of the facts expressed by the statements B, C, D; so that we may know, if B, C, and D are true, then A is true. To many people our inability to understand all that is contained in statements B, C, and D, without the cumbrous process of a mathematical demonstration, proves the feebleness of the human mind as a logical machine. For it required the new point of view imagined by Newton's analysis to enable people to see that, so far as planetary orbits are concerned, Kepler's three laws (B, C, D) were identical with Newton's law of gravitation (A). No one recognises more than the mathematical astronomer this feebleness of the human intellect, and no one is more conscious of the limitations of the logical process called mathematics, which even now has not solved directly the problem of only three bodies.