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]
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 its Neighbouring Stars[415]
84.The Pleiades[416]
85.Orion, Sirius, and Neighbouring Stars[417]
86.Castor and Pollux[418]
87.The Great Bear and the Lion[419]
88.Boötes and the Crown[420]
89.Virgo and Neighbouring Constellations[421]
90.The Constellation of Lyra[422]
91.Vega, the Swan, and the Eagle[423]
92.The Orbit of Sirius[426]
93.The Parallactic Ellipse[444]
94.61 Cygni and the Comparison Stars[447]
95.Parallax in Declination of 61 Cygni[450]
96.Globular Cluster in Hercules[463]
97.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]

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 exquisite beauty. It leads to the contemplation of grand phenomena in nature and great achievements of human genius.

Let us enumerate a few of the questions which will be naturally asked by one who seeks to learn something of those glorious bodies which adorn our skies: What is the Sun—how hot, how big, and how distant? Whence comes its heat? What is the Moon? What are its landscapes like? How does our satellite move? How is it related to the earth? Are the planets globes like that on which we live? How large are they, and how far off? What do we know of the satellites of Jupiter and of the rings of Saturn? How was Uranus discovered? What was the intellectual triumph which brought the planet Neptune to light? Then, as to the other bodies of our system, what are we to say of those mysterious objects, the comets? Can we discover the laws of their seemingly capricious movements? Do we know anything of their nature and of the marvellous tails with which they are often decorated? What can be told about the shooting-stars which so often dash into our atmosphere and perish in a streak of splendour? What is the nature of those constellations of bright stars which have been recognised from all antiquity, and of the host of smaller stars which our telescopes disclose? Can it be true that these countless orbs are really majestic suns, sunk to an appalling depth in the abyss of unfathomable space? What have we to tell of the different varieties of stars—of coloured stars, of variable stars, of double stars, of multiple stars, of stars that seem to move, and of stars that seem at rest? What of those glorious objects, the great star clusters? What of the Milky Way? And, lastly, what can we learn of the marvellous nebulæ which our telescopes disclose, poised at an immeasurable distance? Such are a few of the questions which occur when we ponder on the mysteries of the heavens.

The history of Astronomy is, in one respect, only too like many other histories. The earliest part of it is completely and hopelessly lost. The stars had been studied, and some great astronomical discoveries had been made, untold ages before those to which our earliest historical records extend. For example, the observation of the apparent movement of the sun, and the discrimination between the planets and the fixed stars, are both to be classed among the discoveries of prehistoric ages. Nor is it to be said that these achievements related to matters of an obvious character. Ancient astronomy may seem very elementary to those of the present day who have been familiar from childhood with the great truths of nature, but, in the infancy of science, the men who made such discoveries as we have mentioned must have been sagacious philosophers.