THE STORY OF THE HEAVENS PLATE I. THE PLANET SATURN, IN 1872. THE Story of the Heavens SIR ROBERT STAWELL BALL, LL.D. D.Sc. Author of "Star-Land" FELLOW OF THE ROYAL SOCIETY OF LONDON, HONORARY FELLOW OF THE ROYAL SOCIETY OF EDINBURGH, FELLOW OF THE ROYAL ASTRONOMICAL SOCIETY, SCIENTIFIC ADVISER TO THE COMMISSIONERS OF IRISH LIGHTS, LOWNDEAN PROFESSOR OF ASTRONOMY AND GEOMETRY IN THE UNIVERSITY OF CAMBRIDGE, AND FORMERLY ROYAL ASTRONOMER OF IRELAND WITH TWENTY-FOUR COLOURED PLATES AND NUMEROUS ILLUSTRATIONS NEW AND REVISED EDITION CASSELL and COMPANY, Limited LONDON, PARIS, NEW YORK & MELBOURNE 1900 ALL RIGHTS RESERVED PREFACE TO ORIGINAL EDITION. I have to acknowledge the kind aid which I have received in the preparation of this book. Mr. Nasmyth has permitted me to use some of the beautiful drawings of the Moon, which have appeared in the well-known work published by him in conjunction with Mr. Carpenter. To this source I am indebted for Plates VII., VIII., IX., X., and Figs. 28, 29, 30. Professor Pickering has allowed me to copy some of the drawings made at Harvard College Observatory by Mr. Trouvelot, and I have availed myself of his kindness for Plates I., IV., XII., XV. I am indebted to Professor Langley for Plate II., to Mr. De la Rue for Plates III. and XIV., to Mr. T.E. Key for Plate XVII., to Professor Schiaparelli for Plate XVIII., to the late Professor C. Piazzi Smyth for Fig. 100, to Mr. Chambers for Fig. 7, which has been borrowed from his "Handbook of Descriptive Astronomy," to Dr. Stoney for Fig. 78, and to Dr. Copeland and Dr. Dreyer for Fig. 72. I have to acknowledge the valuable assistance derived from Professor Newcomb's "Popular Astronomy," and Professor Young's "Sun." In revising the volume I have had the kind aid of the Rev. Maxwell Close. I have also to thank Dr. Copeland and Mr. Steele for their kindness in reading through the entire proofs; while I have also occasionally availed myself of the help of Mr. Cathcart. ROBERT S. BALL. Observatory, Dunsink, Co. Dublin. 12th May, 1886. NOTE TO THIS EDITION. I have taken the opportunity in the present edition to revise the work in accordance with the recent progress of astronomy. I am indebted to the Royal Astronomical Society for the permission to reproduce some photographs from their published series, and to Mr. Henry F. Griffiths, for beautiful drawings of Jupiter, from which Plate XI. was prepared. ROBERT S. BALL. Cambridge, 1st May, 1900. CONTENTS. page Introduction 1 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 the Pleiades " " 472 F. ω Centauri " " 474 XVI. Nebulæ observed with Lord Rosse's Telescope " " 476 XVII. The Comet of 1882 " " 357 XVIII. Schiaparelli's Map of Mars " " 221 LIST OF ILLUSTRATIONS. FIG. PAGE 1. Principle of the Refracting Telescope 11 2. Dome of the South Equatorial at Dunsink Observatory, Co. Dublin 12 3. Section of the Dome of Dunsink Observatory 13 4. The Telescope at Yerkes Observatory, Chicago 15 5. Principle of Herschel's Reflecting Telescope 16 6. South Front of the Yerkes Observatory, Chicago 17 7. Lord Rosse's Telescope 18 8. Meridian Circle 20 9. The Great Bear 27 10. Comparative Sizes of the Earth and the Sun 30 11. The Sun, photographed September 22, 1870 33 12. Photograph of the Solar Surface 35 13. An ordinary Sun-spot 36 14. Scheiner's Observations on Sun-spots 38 15. Zones on the Sun's Surface in which Spots appear 39 16. Texture of the Sun and a small Spot 43 17. The Prism 45 18. Dispersion of Light by the Prism 46 19. Prominences seen in Total Eclipses 53 20. View of the Corona in a Total Eclipse 62 21. View of Corona during Eclipse of January 22, 1898 63 22. The Zodiacal Light in 1874 69 23. Comparative Sizes of the Earth and the Moon 73 24. The Moon's Path around the Sun 76 25. The Phases of the Moon 76 26. The Earth's Shadow and Penumbra 78 27. Key to Chart of the Moon (Plate VI.) 81 28. Lunar Volcano in Activity: Nasmyth's Theory 97 29. Lunar Volcano: Subsequent Feeble Activity 97 30. Lunar Volcano: Formation of the Level Floor by Lava 98 31. Orbits of the Four Interior Planets 115 32. The Earth's Movement 116 33. Orbits of the Four Giant Planets 117 34. Apparent Size of the Sun from various Planets 118 35. Comparative Sizes of the Planets 119 36. Illustration of the Moon's Motion 130 37. Drawing an Ellipse 137 38. Varying Velocity of Elliptic Motion 140 39. Equal Areas in Equal Times 141 40. Transit of the Planet of Romance 153 41. Variations in Phase and apparent Size of Mercury 160 42. Mercury as a Crescent 161 43. Venus, May 29, 1889 170 44. Different Aspects of Venus in the Telescope 171 45. Venus on the Sun at the Transit of 1874 177 46. Paths of Venus across the Sun in the Transits of 1874 and 1882 179 47. A Transit of Venus, as seen from Two Localities 183 48. Orbits of the Earth and of Mars 210 49. Apparent Movements of Mars in 1877 212 50. Relative Sizes of Mars and the Earth 216 51, 52. Drawings of Mars 217 53. Elevations and Depressions on the Terminator of Mars 217 54. The Southern Polar Cap on Mars 217 55. The Zone of Minor Planets between Mars and Jupiter 234 56. Relative Dimensions of Jupiter and the Earth 246 57– 60. The Occultation of Jupiter 255 61. Jupiter and his Four Satellites 258 62. Disappearances of Jupiter's Satellites 259 63. Mode of Measuring the Velocity of Light 264 64. Saturn 270 65. Relative Sizes of Saturn and the Earth 273 66. Method of Measuring the Rotation of Saturn's Rings 288 67. Method of Measuring the Rotation of Saturn's Rings 289 68. Transit of Titan and its Shadow 295 69. Parabolic Path of a Comet 339 70. Orbit of Encke's Comet 346 71. Tail of a Comet directed from the Sun 363 72. Bredichin's Theory of Comets' Tails 366 [...]... around the heavens, seems to have been first ascertained by astronomers whose names are unknown The skill of the early Oriental geometers was further evidenced by their determination of the position of the ecliptic with regard to the celestial equator, and by their success in the measurement of the angle between these two important circles on the heavens The principal features of the motion of the moon... demonstrate the apparent annual movement of the sun There could be no rational explanation of the changes in the constellations with the seasons, except by supposing that the place of the sun was altering, so as to make a complete circuit of the heavens in the course of the year This movement of the sun is otherwise confirmed by looking at the west after sunset, and watching the stars As the season...73 Tails of the Comet of 1858 367 74 The Comet of 1744 368 75 The Path of the Fireball of November 6, 1869 375 76 The Orbit of a Shoal of Meteors 378 77 Radiant Point of Shooting Stars 381 78 The History of the Leonids 385 79 Section of the Chaco Meteorite 398 80 The Great Bear and Pole Star 410 81 The Great Bear and Cassiopeia 411 82 The Great Square of Pegasus 413 83 Perseus and... Position of the Great Nebula in Orion 466 98 The Multiple Star θ Orionis 467 99 The Nebula N.G.C 1499 471 100 Star-Map, showing Precessional Movement 493 101 Illustration of the Motion of Precession 495 [Pg 1] THE Story of the Heavens "The Story of the Heavens" is the title of our book We have indeed a wondrous story to narrate; and could we tell it adequately it would prove of boundless interest and of. .. truths of nature, but, in the infancy of science, the men who made such discoveries as we have mentioned must have been sagacious philosophers Of all the phenomena of astronomy the first and the most obvious is that of the rising and the setting of the sun We may assume that in the dawn of human intelligence these daily occurrences would form one of the first problems to engage the attention of those... incurred the wrath of the Inquisition The structure of the human eye in so far as the exquisite adaptation of the pupil is concerned presents us with an apt illustration of the principle of the telescope To see an object, it is necessary that the light from it should enter the eye The portal through which the light is admitted is the pupil In daytime, when the light is brilliant, the iris decreases the. .. which the operation of condensing the rays of light is conducted by refraction The character of the refractor is shown in Fig 1 The rays from the star fall upon the object-glass at the end of the telescope, and on passing through they become refracted into a converging beam, so that all intersect at the focus Diverging from thence, the rays encounter the eye-piece, which has the effect of restoring them... movements of the planets It was found that they obeyed certain laws The cultivation of the science of geometry went hand in hand with the study of astronomy: and as we emerge from the dim prehistoric ages into the historical period, we find that the theory of the phenomena of the heavens possessed already some degree of coherence Ptolemy, following Pythagoras, Plato, and Aristotle, acknowledged that the. .. Observatory for the equatorial telescope, the object-glass of which was presented to the Board of Trinity College, Dublin, by the late Sir James South The main part of the building is a cylindrical wall, on the top of which reposes a hemispherical roof In this roof is a shutter, which can be opened so as to allow the telescope in the interior to obtain a view of the heavens The dome is capable of revolving... comparison between the sighting of a rifle at the target and the sighting of a telescope at a star Instead of the ordinary large bull's-eye, suppose that the target only consisted of a watch-dial, which, of course, the rifleman could not see at the distance of any ordinary range But with the telescope of the meridian circle the watch-dial would be visible even at the distance of a mile The meridian circle . THE STORY OF THE HEAVENS PLATE I. THE PLANET SATURN, IN 1872. THE Story of the Heavens SIR ROBERT STAWELL BALL, LL.D. D.Sc. Author of "Star-Land" FELLOW OF THE ROYAL. from the Sun 363 72. Bredichin's Theory of Comets' Tails 366 73. Tails of the Comet of 1858 367 74. The Comet of 1744 368 75. The Path of the Fireball of November 6, 1869 375 76. The. explanation of the changes in the constellations with the seasons, except by supposing that the place of the sun was altering, so as to make a complete circuit of the heavens in the course of the