CONTENTS

[PART I]
[LECTURE I]
PAGE
COPERNICUS AND THE MOTION OF THE EARTH2
[LECTURE II]
TYCHO BRAHÉ AND THE EARLIEST OBSERVATORY 32
[LECTURE III]
KEPLER AND THE LAWS OF PLANETARY MOTION 56
[LECTURE IV]
GALILEO AND THE INVENTION OF THE TELESCOPE 80
[LECTURE V]
GALILEO AND THE INQUISITION 108
[LECTURE VI]
DESCARTES AND HIS THEORY OF VORTICES136
[LECTURE VII]
SIR ISAAC NEWTON159
[LECTURE VIII]
NEWTON AND THE LAW OF GRAVITATION180
[LECTURE IX]
NEWTON'S "PRINCIPIA"203

[PART II]
[LECTURE X]
ROEMER AND BRADLEY AND THE VELOCITY OF LIGHT232
[LECTURE XI]
LAGRANGE AND LAPLACE—THE STABILITY OF THE SOLAR SYSTEM,AND THE NEBULAR HYPOTHESIS254
[LECTURE XII]
HERSCHEL AND THE MOTION OF THE FIXED STARS273
[LECTURE XIII]
THE DISCOVERY OF THE ASTEROIDS294
[LECTURE XIV]
BESSEL—THE DISTANCES OF THE STARS, AND THE DISCOVERY OFSTELLAR PLANETS304
[LECTURE XV]
THE DISCOVERY OF NEPTUNE317
[LECTURE XVI]
COMETS AND METEORS331
[LECTURE XVII]
THE TIDES353
[LECTURE XVIII]
THE TIDES, AND PLANETARY EVOLUTION379