ILLUSTRATIONS

FIG. PAGE
[1.] Archimedes 8
[2.] Leonardo da Vinci 10
[3.] Copernicus 12
[4.] Homeric Cosmogony 15
[5.] Egyptian Symbol of the Universe 16
[6.] Hindoo Earth 17
[7.] Order of ancient Planets corresponding to the Days of the Week 19
[8.] Ptolemaic System 20
[9.] Specimens of Apparent Paths of Venus and of Mars among the stars 21
[10.] Apparent Epicyclic Orbits of Jupiter and Saturn 22
[11.] Egyptian System 24
[12.] True Orbits of Earth and Jupiter 25
[13.] Orbits of Mercury and Earth 25
[14.] Copernican System as frequently represented 26
[15.] Slow Movement of the North Pole in a Circle among the Stars 29
[16.] Tychonic system, showing the Sun with all the Planets revolving round the Earth 38
[17.] Portrait of Tycho 41
[18.] Early out-door Quadrant of Tycho 43
[19.] Map of Denmark, showing the Island of Huen 45
[20.] Uraniburg 46
[21.] Astrolabe 47
[22.] Tycho's large Sextant 48
[23.] The Quadrant in Uraniburg 49
[24.] Tycho's Form of Transit Circle 50
[25.] A Modern Transit Circle 51
[26.] Orbits of some of the Planets drawn to scale 60
[27.] Many-sided Polygon or Approximate Circle enveloped by Straight Lines 61
[28.] Kepler's Idea of the Regular Solids 62
[29.] Diagram of Equant 67
[30.] Excentric Circle supposed to be divided into equal Areas 68
[31.] Mode of drawing an Ellipse 70
[32.] Kepler's Diagram proving Equable Description of Areas for an Ellipse 71
[33.] Diagram of a Planet's Velocity in Different Parts of its Orbit 72
[34.] Portrait of Kepler 76
[35.] Curve described by a Projectile 82
[36.] Two Forms of Pulsilogy 87
[37.] Tower of Pisa 91
[38.] View of the Half-Moon in small Telescope 97
[39.] Portion of the Lunar Surface more highly magnified 98
[40.] Another Portion of the Lunar Surface 99
[41.] Lunar Landscape showing Earth 100
[42.] Galileo's Method of estimating the Height of Lunar Mountain 101
[43.] Some Clusters and Nebulæ 102
[44.] Stages of the Discovery of Jupiter's Satellites 103
[45.] Eclipses of Jupiter's Satellites 105
[46.] Old Drawings of Saturn by Different Observers, with the imperfect Instruments of that day 111
[47.] Phases of Venus 112
[48.] Sunspots as seen with Low Power 113
[49.] A Portion of the Sun's Disk as seen in a powerful modern Telescope 114
[50.] Saturn and his Rings 115
[51.] Map of Italy 118
[52.] Portrait of Galileo 126
[53.] Portrait of Descartes 148
[54.] Descartes's Eye Diagram 151
[55.] Descartes's Diagram of Vortices from his "Principia" 152
[56.] Manor-house of Woolsthorpe 162
[57.] Projectile Diagram 170
[58.]} {171
[59.]Diagrams illustrative of those near the Beginning of Newton's "Principia"174
[60.] 175
[61-2.] 175
[63.] Prismatic Dispersion 182
[64.] A single Constituent of White Light is capable of no more Dispersion 183
[65.] Parallel Beam passing through a Lens 184
[66.] Newton's Telescope 186
[67.] The Sextant, as now made 187
[68.] Newton when young 196
[69.] Sir Isaac Newton 200
[70.] Another "Principia" Diagram 207
[71.] Well-known Model exhibiting the Oblate Spheroidal Form as a Consequence of spinning about a Central Axis 219
[72.] Jupiter 221
[73.] Diagram of Eye looking at a Light reflected in a Distant Mirror through the Teeth of a revolving Wheel 238
[74.] Fizeau's Wheel, showing the appearance of distant Image seen through its Teeth 239
[75.] Eclipses of one of Jupiter's Satellites 241
[76.] A Transit instrument for the British Astronomical Expedition, 1874 243
[77.] Diagram of equatorially mounted Telescope 245
[78.] Aberration Diagram 250
[79.] Showing the three Conjunction Places in the Orbits of Jupiter and Saturn 259
[80.] Lord Rosse's Drawing of the Spiral Nebula in Canes Venatici 269
[81.] Saturn 271
[82.] Principle of Newtonian Reflector 278
[83.] Herschel's 40-foot telescope 283
[84.] William Herschel 285
[85.] Caroline Herschel 287
[86.] Double Stars 288
[87.] Old Drawing of the Cluster in Hercules 290
[88.] Old Drawing of the Andromeda Nebula 291
[89.] The Great Nebula in Orion 292
[90.] Planetary Orbits to scale 297
[91.] Diagram illustrating Parallax 307
[92.] The Königsberg Heliometer 312
[93.] Perturbations of Uranus 320
[94.] Uranus' and Neptune's Relative Positions 325
[95.] Meteorite 333
[96.] Meteor Stream crossing Field of Telescope 334
[97.] Diagram of Direction of Earth's Orbital Motion 335
[98.] Parabolic and Elliptic Orbits 340
[99.] Orbit of Halley's Comet 341
[100.] Various Appearances of Halley's Comet when last seen 342
[101.] Head of Donati's Comet of 1858 343
[102.] Comet 344
[103.] Encke's Comet 345
[104.] Biela's Comet as last seen in two Portions 346
[105.] Radiant Point Perspective 348
[106.] Present Orbit of November Meteors 349
[107.] Orbit of November Meteors before and after Encounter with Uranus 351
[108.] The Mersey 355
[109.] Co-tidal Lines, showing the way the Tidal Wave reaches the British Isles from the Atlantic 359
[110.] Whirling Earth Model 364
[111.] Earth and Moon Model 365
[112.] Earth and Moon (Earth's Rotation Neglected) 366
[113.] Maps showing how comparatively Free from Land Obstruction the Ocean in the Southern Hemisphere Is 369
[114.] Spring and Neap Tides 370
[115.] Tidal Clock 371
[116.] Sir William Thomson (Lord Kelvin) 373
[117.] Tide-gauge for recording Local Tides 375
[118.] Harmonic Analyzer 375
[119.] Tide-predicter 376
[120.] Weekly Sheet of Curves 377