3
epared.
ROBERT S. BALL.
CAMBRIDGE, 1st May, 1900.
CONTENTS.
PAGE
CHAPTER
I.
THE ASTRONOMICAL OBSERVATORY 9
II. THE SUN 29
III. THE MOON 70
IV. THE SOLAR SYSTEM 107
V. THE LAW OF GRAVITATION 122
VI. THE PLANET OF ROMANCE 150
VII. MERCURY 155
VIII. VENUS 167
IX. THE EARTH 192
X. MARS 208
XI. THE MINOR PLANETS 229
XII. JUPITER 245
XIII. SATURN 268
XIV. URANUS 298
XV. NEPTUNE 315
XVI. COMETS 336
XVII. SHOOTING STARS 372
XVIII. THE STARRY HEAVENS 409
XIX. THE DISTANT SUNS 425
XX. DOUBLE STARS 434
XXI. THE DISTANCES OF THE STARS 441
XXII. STAR CLUSTERS AND NEBULÆ 461
XXIII. THE PHYSICAL NATURE OF THE STARS 477
XXIV. THE PRECESSION AND NUTATION OF THE EARTH'S AXIS 492
XXV. THE ABERRATION OF LIGHT 503
XXVI. THE ASTRONOMICAL SIGNIFICANCE OF HEAT 513
XXVII. THE TIDES 531
APPENDIX 558
LIST OF PLATES.
PLATE
I. The Planet Saturn Frontispiece
II. A Typical Sun-spot To face page 9
A. The Sun " " 44
III. Spots and Faculæ on the Sun " " 37
IV. Solar Prominences or Flames " " 57
V. The Solar Corona " " 62
VI. Chart of the Moon's Surface " " 81
B. Portion of the Moon " " 88
VII. The Lunar Crater Triesnecker " " 93
VIII. A Normal Lunar Crater " " 97
IX. The Lunar Crater Plato " " 102
X. The Lunar Crater Tycho " " 106
XI. The Planet Jupiter " " 254
XII. Coggia's Comet " " 340
C. Comet A., 1892, 1 Swift " " 358
XIII. Spectra of the Sun and of three Stars " " 47
D. The Milky Way, near Messier II. " " 462
XIV. The Great Nebula in Orion " " 466
XV. The Great Nebula in Andromeda " " 468
E. Nebulæ in t