History of Astronomy

History of Astronomy

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Title: History of Astronomy
Author: George Forbes
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[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

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