List of Illustrations xxi.i 



FIG. PAGE 



bg. The parallax of a planet ... 206 



70. Motion in a circle ... ... ... ... 214 



71. The moon as a projectile ... ... ... ... ... 220 



72. The spheroidal form of the earth ... ... 234 



73. An elongated ellipse and a parabola ... ... ... ... 238 



PORTRAIT OF NEWTON To face p. 240 



PORTRAIT OF BRADLEY 258 



74. 75. The aberration of light 262,263 



76. The aberrational ellipse 264 



77. Precession and nutation ... ... ... ... ... 268 



78. The varying curvature of the earth ... ... ... ... 277 



79. Tobias Mayer's map of the moon To face p. 282 



80. The path of Halley's comet 294 



81. A varying ellipse 303 



PORTRAIT OF LAGRANGE To face p. 305 



PORTRAIT OF LAPLACE 307 



PORTRAIT OF WILLIAM HERSCHEL 327 



82. Herschel's forty-foot telescope ... ... 329 



83. Section of the sidereal system ... ... 333 



84. Illustrating the effect of the sun's motion in space... ... 345 



85. 61 Oygni and the two neighbouring stars used by Bessel ... 360 



86. The parallax of 6 1 Cygni 361 



87. The path of Halley's comet 373 



88. Photographic trail of a minor planet ... ... To face p. 377 



89. Paths of minor planets... ... ... ... 378 



90. Comparative sizes of three minor planets and the moon ... 379 



91. Saturn and its system ... ... ... ... 380 



92. Mars and its satellites ... ... 381 



93. Jupiter and its satellites ... ... ... 3^2 



94. The Apennines and the adjoining regions \ T r ^ c, 



of the moon J 



95. Saturn and its rings ... ... ... ... 384 



96. A group of sun-spots ... ... 385 



97. Fraunhofer's map of the solar spectrum ... 387 



98. The total solar eclipse of 1886 ... ... ,, 390 



99. The great comet of 1882 ... ... ... 393 



100. The nebula about 17 Argus ... 397 



101. The orbit of Ursae ... ... ... ... 399 



102. Spiral nebulae ... ... ... To face p. 400 



103. The spectrum of /3 Aurigae ... ... ... fl 403 



104. The Milky Way near the cluster in Perseus 405 



