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diff --git a/old/15620-8.txt b/old/15620-8.txt new file mode 100644 index 0000000..ff3a748 --- /dev/null +++ b/old/15620-8.txt @@ -0,0 +1,7862 @@ +The Project Gutenberg EBook of Recreations in Astronomy, by Henry Warren + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Recreations in Astronomy + With Directions for Practical Experiments and Telescopic Work + +Author: Henry Warren + +Release Date: April 14, 2005 [EBook #15620] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK RECREATIONS IN ASTRONOMY *** + + + + +Produced by Robert J. Hall. + + + + +[Page ii] +[Illustration: THE CONSTELLATIONS OF ORION AND TAURUS. + +NOTES.--Star a in Taurus is red, has eight metals; moves east (page +227). At o above tip of right horn is the Crab Nebula (page 219). +In Orion, a is variable, has five metals; recedes 22 miles per +second. b, d, e, x, r, etc., are double stars, the component parts +of various colors and magnitudes (page 212, note). l and i are +triple; s, octuple; th, multiple, surrounded by a fine Nebula (page +218).] + + + + +[Page iii] +RECREATIONS IN ASTRONOMY + +WITH + +_DIRECTIONS FOR PRACTICAL EXPERIMENTS AND TELESCOPIC WORK_ + + +BY + +HENRY WHITE WARREN, D.D. + +AUTHOR OF "SIGHTS AND INSIGHTS; OR, KNOWLEDGE BY TRAVEL," ETC. + + +WITH EIGHTY-THREE ILLUSTRATIONS AND MAPS OF STARS + + + +[Page v] +[Greek: + TAEI PSUCHAEI + TAEI AGAPAETAEI + ASTRAPOUSAEI + KAI + ISAGGEDOI] + + + + +[Page vii] +PREFACE. + +All sciences are making an advance, but Astronomy is moving at the +double-quick. Since the principles of this science were settled +by Copernicus, four hundred years ago, it has never had to beat +a retreat. It is rewritten not to correct material errors, but +to incorporate new discoveries. + +Once Astronomy treated mostly of tides, seasons, and telescopic +aspects of the planets; now these are only primary matters. Once +it considered stars as mere fixed points of light; now it studies +them as suns, determines their age, size, color, movements, chemical +constitution, and the revolution of their planets. Once it considered +space as empty; now it knows that every cubic inch of it quivers with +greater intensity of force than that which is visible in Niagara. +Every inch of surface that can be conceived of between suns is more +wave-tossed than the ocean in a storm. + +The invention of the telescope constituted one era in Astronomy; +its perfection in our day, another; and the discoveries of the +spectroscope a third--no less important than either of the others. + +While nearly all men are prevented from practical experimentation +in these high realms of knowledge, few [Page viii] have so little +leisure as to be debarred from intelligently enjoying the results +of the investigations of others. + +This book has been written not only to reveal some of the highest +achievements of the human mind, but also to let the heavens declare +the glory of the Divine Mind. In the author's judgment, there is no +gulf that separates science and religion, nor any conflict where +they stand together. And it is fervently hoped that anyone who +comes to a better knowledge of God's works through reading this +book, may thereby come to a more intimate knowledge of the Worker. + +I take great pleasure in acknowledging my indebtedness to J. M. +Van Vleck, LL.D., of the U.S. Nautical Almanac staff, and Professor +of Astronomy at the Wesleyan University, for inspecting some of the +more important chapters; to Dr. S. S. White, of Philadelphia, for +telescopic advantages; to Professor Henry Draper, for furnishing, +in advance of publication, a photograph of the sun's corona in 1878; +and to the excellent work on "Popular Astronomy," by Professor +Simon Newcomb, LL.D., Professor U. S. Naval Observatory, for some +of the most recent information, and for the use of the unequalled +engravings of Jupiter, Saturn, and the great nebula of Orion. + + + + +[Page ix] +CONTENTS. + + CHAP. + I. CREATIVE PROCESSES + II. CREATIVE PROGRESS + Constitution of Light + Chemistry of Suns revealed by Light + Creative Force of Light + III. ASTRONOMICAL INSTRUMENTS + The Telescope + The Reflecting Telescope + The Spectroscope + IV. CELESTIAL MEASUREMENTS + Celestial Movements + How to Measure + V. THE SUN + What the Sun does for us + VI. THE PLANETS, AS SEEN FROM SPACE + The Outlook from the Earth + VII. SHOOTING-STARS, METEORS, AND COMETS + Aerolites + Comets + Famous Comets + Of what do Comets consist? + Will Comets strike the Earth? + VIII. THE PLANETS AS INDIVIDUALS + Vulcan + Mercury + Venus + The Earth + The Aurora Borealis +[Page x] + The Delicate Balance of Forces + Tides + The Moon + Telescopic Appearance + Eclipses + Mars + Satellites of Mars + Asteroids + Jupiter + Satellites of Jupiter + Saturn + Rings of Saturn + Satellites of Saturn + Uranus + Neptune + IX. THE NEBULAR HYPOTHESIS. + X. THE STELLAR SYSTEM + The Open Page of the Heavens + Equatorial Constellations + Characteristics of the Stars + Number + Double and Multiple Stars + Colored Stars + Clusters of Stars + Nebulę + Variable Stars + Temporary, New, and Lost Stars + Movements of Stars + XI. THE WORLDS AND THE WORD + XII. THE ULTIMATE FORCE + SUMMARY OF LATEST DISCOVERIES AND CONCLUSIONS + SOME ELEMENTS OF THE SOLAR SYSTEM + EXPLANATION OF ASTRONOMICAL SYMBOLS + Signs of the Zodiac + Other Abbreviations Used in the Almanac + Greek Alphabet Used Indicating the Stars + CHAUTAUQUA OUTLINE FOR STUDENTS + GLOSSARY OF ASTRONOMICAL TERMS AND INDEX + + + + +[Page xi] +ILLUSTRATIONS + +FIG. + The Constellations of Orion and Taurus + 1. An Orbit resulting from Attraction and Projection + 2. The Moon's Orbit about the Earth + 3. Changes of Orbit by Mutual Attraction + 4. Velocity of Light measured by Jupiter's Satellites + 5. Velocity of Light measured by Fizeau's Toothed Wheel + 6. White Light resolved into Colors + 7. Showing amount of Light received by Different Planets + 8. Measuring Intensities of Lights + 9. Reflection and Diffusion of Light + 10. Manifold Reflections + 11. Refraction by Water + 12. Atmospherical Reflection + 13. Refracting Telescope + 14. Reflecting Telescope + 15. The Cambridge Equatorial Refractor + 16. The new Reflecting Telescope at Paris + 17. Spectroscope, with Battery of Prisms + 18. Spectra of Glowing Hydrogen and of the Sun + 19. Illustrating Arcs and Angles + 20. Measuring Objects by observing Angles + 21. Mural Circle + 22. Scale to measure Hundredths of an Inch + 23. Spider-lines to determine Star Transits + 24. Illustrating Triangulation +[Page xii] + 25. Measuring Distance to an Inaccessible Object + 26. Measuring Elevation of an Inaccessible Object + 27. Illustrating Parallax + 28. Illustrating Stellar Parallax + 29. Mode of Ascertaining Longitude + 30. Relative Size of Sun, as seen from Different Planets + 31. Zodiacal Light + 32. Corona of the Sun in 1858--Brazil + 33. Corona of the Sun in 1878--Colorado + 34. Solar Prominences of Flaming Hydrogen + 35. Changes in Solar Cavities during Rotation + 36. Solar Spot + 37. Holding Telescope to see the Sun-spots + 38. Orbits and Comparative Sizes of the Planets + 39. Orbit of Earth, illustrating Seasons + 40. Inclination of Planes of Planetary Orbits + 41. Inclination of Orbits of Earth and Venus + 42. Showing the Sun's Movement among the Stars + 43. Passage of the Sun by Star Regulus + 44. Apparent Path of Jupiter among the Stars + 45. Illustrating Position of Planets + 46. Apparent Movements of an Inferior Planet + 47. Apparent Movements of a Superior Planet + 47_a_. A Swarm of Meteors meeting the Earth + 48. Explosion of a Bolide + 49. Flight of Bolides + 50. The Santa Rosa Aerolite + 51. Orbit of November Meteors and the Comet of 1866 + 52. Aspects of Remarkable Comets + 53. Phases and Apparent Dimensions of Venus + 54. The Earth and Moon in Space + 55. Aurora as Waving Curtains + 56. Tide resulting from Centrifugal Motion + 57. Lunar Landscape +[Page xiii] + 58. Telescopic View of the Moon + 59. Illumination of Lunar Craters and Peaks + 60. Lunar Crater "Copernicus" + 61. Eclipses: Shadows of Earth and Moon + 62. Apparent Sizes of Mars, seen from the Earth + 63. Jupiter + 64. Various Positions of Jupiter's Satellites + 65. View of Saturn and his Rings + 66. Perturbations of Uranus + 67. Map: Circumpolar Constellations + 68. Map of Constellations on the Meridian in December + 69. Map of Constellations on the Meridian in January + 70. Map of Constellations on the Meridian in April + 71. Map of Constellations on the Meridian in June + 72. Map of Constellations on the Meridian in September + 73. Map of Constellations on the Meridian in November + 74. Southern Circumpolar Constellations + 75. Aspects of Double Stars + 76. Sprayed Star Cluster below ae in Hercules + 77. Globular Star Cluster in the Centaur + 78. Great Nebula about th Orionis + 79. The Crab Nebula above z Tauri + 80. The Ring Nebula in Lyra + 81. Showing Place of Ring Nebula + 82. The Horizontal Pendulum + + COLORED PLATE REPRESENTING VARIOUS SPECTA + MAPS TO FIND THE STARS + + + + +[Page 1] +I. + +CREATIVE PROCESSES. + + "In the beginning God created the heaven and the earth. And the + earth was without form, and void; and darkness was upon the face of the + deep."--_Genesis_ i. 1, 2. + +[Page 2] + "Not to the domes, where crumbling arch and column + Attest the feebleness of mortal hand, + But to that fane, most catholic and solemn, + Which God hath planned,-- + To that cathedral, boundless as our wonder, + Whose quenchless lamps the sun and stars supply; + Its choir the winds and waves, its organ thunder, + Its dome the sky." H. W. LONGFELLOW. + + "The heavens are a point from the pen of His perfection; + The world is a rose-bud from the bower of His beauty; + The sun is a spark from the light of His wisdom; + And the sky a bubble on the sea of His power." + SIR W. JONES. + + +[Page 3] +RECREATIONS IN ASTRONOMY. + + * * * * * + +I. + +_CREATIVE PROCESSES._ + +During all the ages there has been one bright and glittering page +of loftiest wisdom unrolled before the eye of man. That this page +may be read in every part, man's whole world turns him before it. +This motion apparently changes the eternally stable stars into a +moving panorama, but it is only so in appearance. The sky is a +vast, immovable dial-plate of "that clock whose pendulum ticks +ages instead of seconds," and whose time is eternity. The moon +moves among the illuminated figures, traversing the dial quickly, +like a second-hand, once a month. The sun, like a minute-hand, goes +over the dial once a year. Various planets stand for hour-hands, +moving over the dial in various periods reaching up to one hundred +and sixty-four years; while the earth, like a ship of exploration, +sails the infinite azure, bearing the observers to different points +where they may investigate the infinite problems of this mighty +machinery. + +This dial not only shows present movements, but it keeps the history +of uncounted ages past ready to be [Page 4] read backward in proper +order; and it has glorious volumes of prophecy, revealing the +far-off future to any man who is able to look thereon, break the +seals, and read the record. Glowing stars are the alphabet of this +lofty page. They combine to form words. Meteors, rainbows, auroras, +shifting groups of stars, make pictures vast and significant as the +armies, angels, and falling stars in the Revelation of St. +John--changing and progressive pictures of infinite wisdom and +power. + +Men have not yet advanced as far as those who saw the pictures John +describes, and hence the panorama is not understood. That continuous +speech that day after day uttereth is not heard; the knowledge that +night after night showeth is not seen; and the invisible things +of God from the creation of the world, even his eternal power and +Godhead, clearly discoverable from things that are made, are not +apprehended. + +The greatest triumphs of men's minds have been in astronomy--and +ever must be. We have not learned its alphabet yet. We read only +easy lessons, with as many mistakes as happy guesses. But in time we +shall know all the letters, become familiar with the combinations, +be apt at their interpretation, and will read with facility the +lessons of wisdom and power that are written on the earth, blazoned +in the skies, and pictured by the flowers below and the rainbows +above. + +In order to know how worlds move and develop, we must create them; +we must go back to their beginning, give their endowment of forces, +and study the laws of their unfolding. This we can easily do by that +faculty wherein man is likest his Father, a creative imagination. +God creates and embodies; we create, but [Page 5] it remains in +thought only. But the creation is as bright, strong, clear, +enduring, and real, as if it were embodied. Every one of us would +make worlds enough to crush us, if we could embody as well as +create. Our ambition would outrun our wisdom. Let us come into the +high and ecstatic frame of mind which Shakspeare calls frenzy, in +the exigencies of his verse, when + + "The poet's eye, in a fine frenzy rolling, + Doth glance from heaven to earth, from earth to heaven; + And, as imagination bodies forth + The forms of things unknown, the poet's pen + Turns them to shapes, and gives to airy nothing + A local habitation and a name." + +In the supremacy of our creative imagination let us make empty +space, in order that we may therein build up a new universe. Let us +wave the wand of our power, so that all created things disappear. +There is no world under our feet, no radiant clouds, no blazing +sun, no silver moon, nor twinkling stars. We look up, there is +no light; down, through immeasurable abysses, there is no form; +all about, and there is no sound or sign of being--nothing save +utter silence, utter darkness. It cannot be endured. Creation is +a necessity of mind--even of the Divine mind. + +We will now, by imagination, create a monster world, every atom +of which shall be dowered with the single power of attraction. +Every particle shall reach out its friendly hand, and there shall +be a drawing together of every particle in existence. The laws +governing this attraction shall be two. When these particles are +associated together, the attraction shall be in proportion to the +mass. A given mass will pull twice [Page 6] as much as one of half +the size, because there is twice as much to pull. And a given mass +will be pulled twice as much as one half as large, because there is +twice as much to be pulled. A man who weighed one hundred and fifty +pounds on the earth might weigh a ton and a half on a body as large +as the sun. That shall be one law of attraction; and the other shall +be that masses attract inversely as the square of distances between +them. Absence shall affect friendships that have a material basis. +If a body like the earth pulls a man one hundred and fifty pounds at +the surface, or four thousand miles from the centre, it will pull +the same man one-fourth as much at twice the distance, one-sixteenth +as much at four times the distance. That is, he will weigh by a +spring balance thirty-seven and a half pounds at eight thousand +miles from the centre, and nine pounds six ounces at sixteen +thousand miles from the centre, and he will weigh or be pulled by +the earth 1/24 of a pound at the distance of the moon. But the moon +would be large enough and near enough to pull twenty-four pounds on +the same man, so the earth could not draw him away. Thus the two +laws of attraction of gravitation are--1, _Gravity is proportioned +to the quantity of matter_; and 2, _The force of gravity varies +inversely as the square of the distance from the centre of the +attracting body_. + +The original form of matter is gas. Almost as I write comes the +announcement that Mr. Lockyer has proved that all the so-called +primary elements of matter are only so many different sized molecules +of one original substance--hydrogen. Whether that is true or not, +let us now create all the hydrogen we can [Page 7] imagine, either +in differently sized masses or in combination with other substances. +There it is! We cannot measure its bulk; we cannot fly around it in +any recordable eons of time. It has boundaries, to be sure, for we +are finite, but we cannot measure them. Let it alone, now; leave it +to itself. What follows? It is dowered simply with attraction. The +vast mass begins to shrink, the outer portions are drawn inward. +They rush and swirl in vast cyclones, thousands of miles in extent. +The centre grows compact, heat is evolved by impact, as will be +explained in Chapter II. Dull red light begins to look like coming +dawn. Centuries go by; contraction goes on; light blazes in +insufferable brightness; tornadoes, whirlpools, and tempests +scarcely signify anything as applied to such tumultuous tossing. + +There hangs the only world in existence; it hangs in empty space. +It has no tendency to rise; none to fall; none to move at all in +any direction. It seethes and, flames, and holds itself together +by attractive power, and that is all the force with which we have +endowed it. + +Leave it there alone, and withdraw millions of miles into space: +it looks smaller and smaller. We lose sight of those distinctive +spires of flame, those terrible movements. It only gives an even +effulgence, a steady unflickering light. Turn one quarter round. +Still we see our world, but it is at one side. + +Now in front, in the utter darkness, suddenly create another world +of the same size, and at the same distance from you. There they +stand--two huge, lone bodies, in empty space. But we created them +dowered with attraction. Each instantly feels the drawing influence +of the other. They are mutually attractive, and begin to [Page 8] +move toward each other. They hasten along an undeviating straight +line. Their speed quickens at every mile. The attraction increases +every moment. They fly swift as thought. They dash their flaming, +seething foreheads together. + +And now we have one world again. It is twice as large as before, +that is all the difference. There is no variety, neither any motion; +just simple flame, and nothing to be warmed thereby. Are our creative +powers exhausted by this effort? + +[Illustration: Fig. 1.--Orbit A D, resulting from attraction, A +C, and projectile force, A B.] + +No, we will create another world, and add another power to it that +shall keep them apart. That power shall be what is called the force +of inertia, which is literally no power at all; it is an inability +to originate or change motion. If a body is at rest, inertia is +that quality by which it will forever remain so, unless acted upon +by some force from without; and if a body is in motion, it will +continue on at the same speed, in a straight line, forever, unless +it is quickened, retarded, or turned from its path by some other +force. Suppose our newly created sun is 860,000 miles in diameter. +Go away 92,500,000 miles and create an earth eight thousand miles +in diameter. It instantly feels the attractive power of the sun +drawing it to itself sixty-eight [Page 9] miles a second. Now, just +as it starts, give this earth a push in a line at right angles with +line of fall to the sun, that shall send it one hundred and +eighty-nine miles a second. It obeys both forces. The result is that +the world moves constantly forward at the same speed by its inertia +from that first push, and attraction momentarily draws it from its +straight line, so that the new world circles round the other to the +starting-point. Continuing under the operation of both forces, the +worlds can never come together or fly apart. + +They circle about each other as long as these forces endure; for +the first world does not stand still and the second do all the +going; both revolve around the centre of gravity common to both. +In case the worlds are equal in mass, they will both take the same +orbit around a central stationary point, midway between the two. +In case their mass be as one to eighty-one, as in the case of the +earth and the moon, the centre of gravity around which both turn +will be 1/81 of the distance from the earth's centre to the moon's +centre. This brings the central point around which both worlds +swing just inside the surface of the earth. It is like an apple +attached by a string, and swung around the hand; the hand moves +a little, the apple very much. + +Thus the problem of two revolving bodies is readily comprehended. +The two bodies lie in easy beds, and swing obedient to constant +forces. When another body, however, is introduced, with its varying +attraction, first on one and then on the other, complications are +introduced that only the most masterly minds can follow. Introduce +a dozen or a million bodies, and complications arise that only +Omniscience can unravel. + +[Page 10] +[Illustration: Fig. 2.] + +Let the hand swing an apple by an elastic cord. When the apple +falls toward the earth it feels another force besides that derived +from the hand, which greatly lengthens the elastic cord. To tear +it away from the earth's attraction, and make it rise, requires +additional force, and hence the string is lengthened; but when +it passes over the hand the earth attracts it downward, and the +string is very much shortened: so the moon, held by an elastic cord, +swings around the earth. From its extreme distance from the earth, +at A, Fig. 2, it rushes with increasing speed nearly a quarter of a +million of miles toward the sun, feeling its attraction increase +with every mile until it reaches B; then it is retarded in its +speed, by the same attraction, as it climbs back its quarter of +a million of miles away from the sun, in defiance of its power, +to C. All the while the invisible elastic force of the earth is +unweariedly maintained; and though the moon's distances vary over a +range of 31,355 miles, the moon is always in a determinable place. +A simple revolution of one world about another in a circular orbit +would be a problem of easy solution. It would always be at the +same distance from its centre, and going with the same velocity. +But there are over sixty causes that interfere with such a simple +orbit in the case of the moon, all of which causes and their +disturbances must be considered in calculating such a simple matter +as an eclipse, or predicting the moon's place as the sailors guide. +One of the most puzzling of the irregularities [Page 11] of our +night-wandering orb has just been explained by Professor Hansen, of +Gotha, as a curious result of the attraction of Venus. + +[Illustration: Fig. 3.--Changes of orbit by mutual attraction.] + +Take a single instance of the perturbations of Jupiter and Saturn +which can be rendered evident. The times of orbital revolution of +Saturn and Jupiter are nearly as five to two. Suppose the orbits of +the planets to be, as in Fig. 3, both ellipses, but not necessarily +equally distant in all parts. The planets are as near as possible +at 1, 1. Drawn toward each other by mutual attraction, Jupiter's +orbit bends outward, and Saturn's becomes more nearly straight, as +shown by the dotted lines. A partial correction of this difficulty +immediately follows. As Jupiter moves on ahead of Saturn it is held +back--retarded in its orbit by that body; and Saturn is hastened +in its orbit by the attraction of Jupiter. Now greater speed means +a straighter orbit. A rifle-ball flies nearer in a straight line +than a thrown stone. A greater velocity given to a whirled ball +pulls the elastic cord far enough to give the ball a larger orbit. +Hence, being hastened, Saturn stretches out nearer its proper orbit, +and, retarded, Jupiter approaches the smaller curve that is its +true orbit. + +But if they were always to meet at this point, as they would if +Jupiter made two revolutions to Saturn's one, it would be disastrous. +In reality, when Saturn has gone around two-thirds of its orbit to +2, Jupiter will have gone once and two-thirds around and overtaken +[Page 12] Saturn; and they will be near again, be drawn together, +hastened, and retarded, as before; their next conjunction would be +at 3, 3, etc. + +Now, if they always made their conjunction at points equally distant, +or at thirds of their orbits, it would cause a series of increasing +deviations; for Jupiter would be constantly swelling his orbit at +three points, and Saturn increasingly contracting his orbit at +the same points. Disaster would be easily foretold. But as their +times of orbital revolutions are not exactly in the ratio of five +and two, their points of conjunction slowly travel around the orbit, +till, in a period of nine hundred years, the starting-point is +again reached, and the perturbations have mutually corrected one +another. + +For example, the total attractive effect of one planet on the other +for 450 years is to quicken its speed. The effect for the next 450 +years is to retard. The place of Saturn, when all the retardations +have accumulated for 450 years, is one degree behind what it is +computed if they are not considered; and 450 years later it will +be one degree before its computed place--a perturbation of two +degrees. When a bullet is a little heavier or ragged on one side, +it will constantly swerve in that direction. The spiral groove in +the rifle, of one turn in forty-five feet, turns the disturbing +weight or raggedness from side to side--makes one error correct +another, and so the ball flies straight to the bull's-eye. So the +place of Jupiter and Saturn, though further complicated by four +moons in the case of Jupiter, and eight in the case of Saturn, and +also by perturbations caused by other planets, can be calculated +with exceeding nicety. + +The difficulties would be greatly increased if the orbits [Page 13] +of Saturn and Jupiter, instead of being 400,000,000 miles apart, +were interlaced. Yet there are the orbits of one hundred and +ninety-two asteroids so interlaced that, if they were made of wire, +no one could be lifted without raising the whole net-work of them. +Nevertheless, all these swift chariots of the sky race along the +course of their intermingling tracks as securely as if they were +each guided by an intelligent mind. _They are guided by an +intelligent mind and an almighty arm._ + +Still more complicated is the question of the mutual attractions of +all the planets. Lagrange has been able to show, by a mathematical +genius that seems little short of omniscience in his single department +of knowledge, that there is a discovered system of oscillations, +affecting the entire planetary system, the periods of which are +immensely long. The number of these oscillations is equal to that +of all the planets, and their periods range from 50,000 to 2,000,000 +years, + +Looking into the open page of the starry heavens we see double +stars, the constituent parts of which must revolve around a centre +common to them both, or rush to a common ruin. Eagerly we look +to see if they revolve, and beholding them in the very act, we +conclude, not groundlessly, that the same great law of gravitation +holds good in distant stellar spaces, and that there the same sufficient +mind plans, and the same sufficient power directs and controls all +movements in harmony and security. + +When we come to the perturbations caused by the mutual attractions +of the sun, nine planets, twenty moons, one hundred and ninety-two +asteroids, millions [Page 14] of comets, and innumerable meteoric +bodies swarming in space, and when we add to all these, that belong +to one solar system, the attractions of all the systems of the other +suns that sparkle on a brilliant winter night, we are compelled to +say, "As high as the heavens are above the earth, so high above our +thoughts and ways must be the thoughts and ways of Him who +comprehends and directs them all." + + + + +[Page 15] +II. + +CREATIVE PROGRESS. + + "And God said, Let there be light, and there was light."--_Genesis_ + i., 3. + + "God is light."--1 _John_, i. 5. + +[Page 16] + "Hail! holy light, offspring of Heaven first born, + Or of the eternal, co-eternal beam, + May I express thee unblamed? since God is light, + And never but in unapproached light + Dwelt from eternity, dwelt then in thee, + Bright effluence of bright essence increate." + MILTON. + + "A million torches lighted by Thy hand + Wander unwearied through the blue abyss: + They own Thy power, accomplish Thy command, + All gay with life, all eloquent with bliss. + What shall we call them? Piles of crystal light-- + A glorious company of golden streams-- + Lamps of celestial ether burning bright-- + Suns lighting systems with their joyous beams? + But 'Thou to these art as the noon to night." + DERZHAVIN, trans. by BOWRING. + + + + +[Page 17] +II. + +_CREATIVE PROGRESS._ + +Worlds would be very imperfect and useless when simply endowed +with attraction and inertia, if no time were allowed for these +forces to work out their legitimate results. We want something +more than swirling seas of attracted gases, something more than +compacted rocks. We look for soil, verdure, a paradise of beauty, +animal life, and immortal minds. Let us go on with the process. + +Light is the child of force, and the child, like its father, is full +of power. We dowered our created world with but a single quality--a +force of attraction. It not only had attraction for its own material +substance, but sent out an all-pervasive attraction into space. By +the force of condensation it flamed like a sun, and not only lighted +its own substance, but it filled all space with the luminous outgoings +of its power. A world may be limited, but its influence cannot; +its body may have bounds, but its soul is infinite. Everywhere is +its manifestation as real, power as effective, presence as actual, +as at the central point. He that studies ponderable bodies alone +is not studying the universe, only its skeleton. Skeletons are +somewhat interesting in themselves, but far more so when covered +with flesh, flushed with beauty, and inspired with soul. The +universe [Page 18] has bones, flesh, beauty, soul, and all is one. +It can be understood only by a study of all its parts, and by +tracing effect to cause. + +But how can condensation cause light? Power cannot be quiet. The +mighty locomotive trembles with its own energy. A smitten piece +of iron has all its infinitesimal atoms set in vehement commotion; +they surge back and forth among themselves, like the waves of a +storm-blown lake. Heat is a mode of motion. A heated body commences +a vigorous vibration among its particles, and communicates these +vibrations to the surrounding air and ether. When these vibrations +reach 396,000,000,000,000 per second, the human eye, fitted to be +affected by that number, discerns the emitted undulations, and the +object seems to glow with a dull red light; becoming hotter, the +vibrations increase in rapidity. When they reach 765,000,000,000,000 +per second the color becomes violet, and the eye can observe them no +farther. Between these numbers are those of different rapidities, +which affect the eye--as orange, yellow, green, blue, indigo, in an +almost infinite number of shades--according to the sensitiveness +of the eye. + +We now see how our dark immensity of attractive atoms can become +luminous. A force of compression results in vibrations within, +communicated to the ether, discerned by the eye. Illustrations are +numerous. If we suddenly push a piston into a cylinder of brass, +the force produces heat enough to set fire to an inflammable substance +within. Strike a half-inch cube of iron a moderate blow and it becomes +warm; a sufficient blow, and its vibrations become quick enough to +be seen--it is red-hot. Attach a thermometer to an extended [Page +19] arm of a whirling wheel; drive it against the air five hundred +feet per second, the mercury rises 16°. The earth goes 98,000 feet +per second, or one thousand miles a minute. If it come to an +aerolite or mass of metallic rock, or even a cloudlet of gas, +standing still in space, its contact with our air evolves 600,000° +of heat. And when the meteor comes toward the world twenty-six miles +a second, the heat would become proportionally greater if the meteor +could abide it, and not be consumed in fervent heat. It vanishes +almost as soon as seen. If there were meteoric masses enough lying +in our path, our sky would blaze with myriads of flashes of light. +Enough have been seen to enable a person to read by them at night. +If a sufficient number were present, we should miss their individual +flashes as they blend their separate fires in one sea of +insufferable glory. The sun is 1,300,000 times as large as our +planet; its attraction proportionally greater; the aerolites more +numerous; and hence an infinite hail of stones, small masses and +little worlds, makes ceaseless trails of light, whose individuality +is lost in one dazzling sea of glory. + +On the 1st day of September, 1859, two astronomers, independently +of each other, saw a sudden brightening on the surface of the sun. +Probably two large meteoric masses were travelling side by side +at two or three hundred miles per second, and striking the sun's +atmosphere, suddenly blazed into light bright enough to be seen +on the intolerable light of the photosphere as a background. The +earth responded to this new cause of brilliance and heat in the +sun. Vivid auroras appeared, not only at the north and south poles, +but even where such spectacles are seldom seen. The electro-magnetic +[Page 20] disturbances were more distinctly marked. "In many places +the telegraphic wires struck work. In Washington and Philadelphia +the electric signalmen received severe electric shocks; at a station +in Norway the telegraphic apparatus was set fire to; and at Boston a +flame of fire followed the pen of Bain's electric telegraph." There +is the best of reason for believing that a continuous succession of +such bodies might have gone far toward rendering the earth +uncomfortable as a place of residence. + +Of course, the same result of heat and light would follow from +compression, if a body had the power of contraction in itself. We +endowed every particle of our gas, myriads of miles in extent, with an +attraction for every other particle. It immediately compressed itself +into a light-giving body, which flamed out through the interstellar +spaces, flushing all the celestial regions with exuberant light. + +But heat exerts a repellent force among particles, and soon an +equilibrium is reached, for there comes a time when the contracting +body can contract no farther. But heat and light radiate away into +cold space, then contraction goes on evolving more light, and so +the suns flame on through the millions of years unquenched. It is +estimated that the contraction of our sun, from filling immensity +of space to its present size, could not afford heat enough to last +more than 18,000,000 years, and that its contraction from its present +density (that of a swamp) to such rock as that of which our earth +is composed, could supply heat enough for 17,000,000 years longer. +But the far-seeing mind of man knows a time must come when the +present force of attraction [Page 21] shall have produced all the +heat it can, and a new force of attraction must be added, or the sun +itself will become cold as a cinder, dead as a burned-out char. + +Since light and heat are the product of such enormous cosmic forces, +they must partake of their nature, and be force. So they are. The +sun has long arms, and they are full of unconquerable strength +ninety-two millions, or any other number of millions, of miles +away. All this light and heat comes through space that is 200° +below zero, through utter darkness, and appears only on the earth. +So the gas is darkness in the underground pipes, but light at the +burner. So the electric power is unfelt by the cable in the bosom +of the deep, but is expressive of thought and feeling at the end. +Having found the cause of light, we will commence a study of its +qualities and powers. + +Light is the astronomer's necessity. When the sublime word was +uttered, "Let there be light!" the study of astronomy was made +possible. Man can gather but little of it with his eye; so he takes +a lens twenty-six inches in diameter, and bends all the light that +passes through it to a focus, then magnifies the image and takes +it into his eye. Or he takes a mirror, six feet in diameter, so +hollowed in the middle as to reflect all the rays falling upon it +to one point, and makes this larger eye fill his own with light. +By this larger light-gathering he discerns things for which the +light falling on his pupil one-fifth of an inch in diameter would +not be sufficient. We never have seen any sun or stars; we have +only seen the light that left them fifty minutes or years ago, more +or less. Light is the aėrial sprite that carries our measuring-rods +across the infinite [Page 22] spaces; light spreads out the history +of that far-off beginning; brings us the measure of stars a thousand +times brighter than our sun; takes up into itself evidences of the +very constitutional elements of the far-off suns, and spreads them +at our feet. It is of such capacity that the Divine nature, looking +for an expression of its own omnipotence, omniscience, and power of +revelation, was content to say, "God is Light." We shall need all +our delicacy of analysis and measurement when we seek to determine +the activities of matter so fine and near to spirit as light. + +[Illustration: Fig. 4.--Velocity of Light measured by Eclipses of +Jupiter's Moons.] + +We first seek the velocity of light. In Fig. 4 the earth is 92,500,000 +miles from the sun at E; Jupiter is 480,000,000 miles from the sun +at J. It has four moons: the inner one goes around the central +body in forty-two hours, and is eclipsed at every revolution. The +light that went out from the sun to M ceases to be reflected back +to the earth by the intervention of the planet Jupiter. We know +to a second when these eclipses take place, and they can be seen +with a small telescope. But when the earth is on the opposite side +of the sun [Page 23] from Jupiter, at E', these eclipses at J' take +place sixteen and a half minutes too late. What is the reason? Is +the celestial chronometry getting deranged? No, indeed; these great +worlds swing never an inch out of place, nor a second out of time. +By going to the other side of the sun the earth is 184,000,000 miles +farther from Jupiter, and the light that brings the intelligence of +that eclipse consumes the extra time in going over the extra +distance. Divide one by the other and we get the velocity, 185,000 +miles per second. That is probably correct to within a thousand +miles. Methods of measurement by the toothed wheel of Fizeau confirm +this result. Suppose the wheel, Fig. 5, to have one thousand teeth, +making five revolutions to the second. Five thousand flashes of +light each second will dart out. Let each flash travel nine miles to +a mirror and return. If it goes that distance in 1/10000 of a +second, or at the rate of 180,000 miles a second, the next tooth +will have arrived before the eye, and each returning ray be cut off. +Hasten the revolutions a little, and the next notch will then admit +the ray, on its return, that went out of each previous notch: the +eighteen miles having been traversed meanwhile. The method of +measuring by means of a revolving mirror, used by Faucault, is held +to be even more accurate. + +[Illustration: Fig. 5.--Measuring the Velocity of Light.] + +When we take instantaneous photographs by the exposure [Page 24] of +the sensitive plate 1/20000 part of a second, a stream of light nine +miles long dashes in upon the plate in that very brief period of +time. + +The highest velocity we can give a rifle-ball is 2000 feet a second, +the next second it is only 1500 feet, and soon it comes to rest. +We cannot compact force enough behind a bit of lead to keep it +flying. But light flies unweariedly and without diminution of speed. +When it has come from the sun in eight minutes, Alpha Centauri +in three years, Polaris in forty-five years, other stars in one +thousand, its wings are in nowise fatigued, nor is the rapidity +of its flight slackened in the least. + +It is not the transactions of to-day that we read in the heavens, +but it is history, some of it older than the time of Adam. Those +stars may have been smitten out of existence decades of centuries +ago, but their poured-out light is yet flooding the heavens. + +It goes both ways at once in the same place, without interference. +We see the light reflected from the new moon to the earth; reflected +back from the house-tops, fields, and waters of earth, to the moon +again, and from the moon to us once more--three times in opposite +directions, in the same place, without interference, and thus we +see "the old moon in the arms of the new." + +_Constitution of Light._ + +[Illustration: Fig. 6.--White Light resolved into Colors.] + +Light was once supposed to be corpuscular, or consisting of transmitted +particles. It is now known to be the result of undulations in ether. +Reference has been made to the minuteness of these undulations. +Their velocity is equally wonderful. Put a prism of glass into +a ray of light coming into a dark room, and it is [Page 25] +instantly turned out of its course, some parts more and some less, +according to the number of vibrations, and appears as the seven +colors on different parts of the screen. Fig. 6 shows the +arrangement of colors, and the number of millions of millions of +vibrations per second of each. But the different divisions we call +colors are not colors in themselves at all, but simply a different +number of vibrations. Color is all in the eye. Violet has in +different places from 716 to 765,000,000,000,000 of vibrations per +second; red has, in different places, from 396 to +470,000,000,000,000 vibrations per second. None of these in any +sense are color, but affect the eye differently, and we call these +different effects color. They are simply various velocities of +vibration. An object, like one kind of stripe in our flag, which +absorbs all kinds of vibrations except those between 396 and +470,000,000,000,000, and reflects those, appears red to us. The +field for the stars absorbs and destroys all but those vibrations +numbering about 653,000,000,000,000 of [Page 25] vibrations per +second. A color is a constant creation. Light makes momentary color +in the flag. Drake might have written, in the continuous present as +well as in the past, + + "Freedom mingles with its gorgeous dyes + The milky baldrick of the skies, + And stripes its pore celestial white + With streakings of the morning light." + +Every little pansy, tender as fancy, pearled with evanescent dew, +fresh as a new creation of sunbeams, has power to suppress in one +part of its petals all vibrations we call red, in another those +we call yellow, and purple, and reflect each of these in other +parts of the same tender petal. "Pansies are for thoughts," even +more thoughts than poor Ophelia knew. An evening cloud that is +dense enough to absorb all the faster and weaker vibrations, leaving +only the stronger to come through, will be said to be red; because +the vibrations that produce the impression we have so named are +the only ones that have vigor enough to get through. It is like an +army charging upon a fortress. Under the deadly fire and fearful +obstructions six-sevenths go down, but one-seventh comes through +with the glory of victory upon its face. + +Light comes in undulations to the eye, as tones of sound to the +ear. Must not light also sing? The lowest tone we can hear is made +by 16.5 vibrations of air per second; the highest, so shrill and +"fine that nothing lives 'twixt it and silence," is made by 38,000 +vibrations per second. Between these extremes lie eleven octaves; +C of the G clef having 258-7/8 vibrations to the second, and its +octave above 517-1/2. Not that sound vibrations cease [Page 27] at +38,000, but our organs are not fitted to hear beyond those +limitations. If our ears were delicate enough, we could hear even up +to the almost infinite vibrations of light. In one of those +semi-inspirations we find in Shakspeare's works, he says-- + + "There's not the smallest orb which thou beholdest, + But in his motion like an angel sings, + Still quiring to the young-eyed cherubim. + Such harmony is in immortal souls; + But, whilst this muddy vesture of decay + Doth grossly close it in, we cannot hear it." + +And that older poetry which is always highest truth says, "The +morning stars sing together." We misconstrued another passage which +we could not understand, and did not dare translate as it was written, +till science crept up to a perception of the truth that had been +standing there for ages, waiting a mind that could take it in. +Now we read as it is written--"Thou makest the out-goings of the +morning and evening to sing." Were our senses fine enough, we could +hear the separate keynote of every individual star. Stars differ +in glory and in power, and so in the volume and pitch of their +song. Were our hearing sensitive enough, we could hear not only +the separate key-notes but the infinite swelling harmony of these +myriad stars of the sky, as they pour their mighty tide of united +anthems in the ear of God: + + "In reason's ear they all rejoice, + And utter forth a glorious voice. + Forever singing, as they shine, + The hand that made us is divine." + +This music is not monotonous. Stars draw near each other, and make +a light that is unapproachable by mortals; [Page 28] then the music +swells beyond our ability to endure. They recede far away, making a +light so dim that the music dies away, so near to silence that only +spirits can perceive it. No wonder God rejoices in his works. They +pour into his ear one ceaseless tide of rapturous song. + +Our senses are limited--we have only five, but there is room for +many more. Some time we shall be taken out of "this muddy vesture +of decay," no longer see the universe through crevices of our +prison-house, but shall range through wider fields, explore deeper +mysteries, and discover new worlds, hints of which have never yet +been blown across the wide Atlantic that rolls between them and +men abiding in the flesh. + +_Chemistry of Suns revealed by Light._ + +When we examine the assemblage of colors spread from the white ray +of sunlight, we do not find red simple red, yellow yellow, etc., +but there is a vast number of fine microscopic lines of various +lengths, parallel--here near together, there far apart, always the +same number and the same relative distance, when the same light +and prism are used. What new alphabets to new realms of knowledge +are these! Remember, that what we call colors are only various +numbers of vibrations of ether. Remember, that every little group in +the infinite variety of these vibrations may be affected differently +from every other group. One number of these is bent by the prism +to where we see what we call the violet, another number to the +place we call red. All of the vibrations are destroyed when they +strike a surface we call black. A part of them are destroyed when +[Page 29] they strike a substance we call colored. The rest are +reflected, and give the impression of color. In one place on the +flag of our nation all vibrations are destroyed except the red; in +another, all but the blue. Perhaps on that other gorgeous flag, not +of our country but of our sun, the flag we call the solar spectrum, +all vibrations are destroyed where these dark lines appear. Perhaps +this effect is not produced by the surface upon which the rays fall, +but by some specific substance in the sun. This is just the truth. +Light passing through vapor of sodium has the vibrations that would +fall on two narrow lines in the yellow utterly destroyed, leaving +two black spaces. Light passing through vapor of burning iron has +some four hundred numbers or kinds of vibrations destroyed, leaving +that number of black lines; but if the salt or iron be glowing gas, +in the source of the light itself the same lines are bright instead +of dark. + +Thus we have brought to our doors a readable record of the very +substances composing every world hot enough to shine by its own +light. Thus, while our flag means all we have of liberty, free as +the winds that kiss it, and bright as the stars that shine in it, +the flag of the sun means all that it is in constituent elements, +all that it is in condition. + +We find in our sun many substances known to exist in the earth, +and some that we had not discovered when the sun wrote their names, +or rather made their mark, in the spectrum. Thus, also, we find +that Betelguese and Algol are without any perceivable indications +of hydrogen, and Sirius has it in abundance. What a sense of +acquaintanceship it gives us to look up and recognize [Page 30] the +stars whose very substance we know! If we were transported thither, +or beyond, we should not be altogether strangers in an unknown +realm. + +But the stars differ in their constituent elements; every ray that +flashes from them bears in its very being proofs of what they are. +Hence the eye of Omniscience, seeing a ray of light anywhere in +the universe, though gone from its source a thousand years, would +be able to tell from what orb it originally came. + +_Creative Force of Light._ + +Just above the color vibrations of the unbraided sunbeam, above +the violet, which is the highest number our eyes can detect, is +a chemical force; it works the changes on the glass plate in +photography; it transfigures the dark, cold soil into woody fibre, +green leaf, downy rose petals, luscious fruit, and far pervasive +odor; it flushes the wide acres of the prairie with grass and flowers, +fills the valleys with trees, and covers the hills with corn, a +single blade of which all the power of man could not make. + +This power is also fit and able to survive. The engineer Stephenson +once asked Dr. Buckland, "What is the power that drives that train?" +pointing to one thundering by. "Well, I suppose it is one of your +big engines." "But what drives the engine?" "Oh, very likely a canny +Newcastle driver." "No, sir," said the engineer, "it is sunshine." +The doctor was too dull to take it in. Let us see if we can trace +such an evident effect to that distant cause. Ages ago the warm +sunshine, falling on the scarcely lifted hills of Pennsylvania, +caused the reedy vegetation to grow along the banks of [Page 31] +shallow seas, accumulated vast amounts of this vegetation, sunk it +beneath the sea, roofed it over with sand, compacted the sand into +rock, and changed this vegetable matter--the products of the +sunshine--into coal; and when it was ready, lifted it once more, all +garnered for the use of men, roofed over with mighty mountains. We +mine the coal, bring out the heat, raise the steam, drive the train, +so that in the ultimate analyses it is sunshine that drives the +train. These great beds of coal are nothing but condensed +sunshine--the sun's great force, through ages gone, preserved for +our use to-day. And it is so full of force that a piece of coal that +will weigh three pounds (as big as a large pair of fists) has as +much power in it as the average man puts into a day's work. Three +tons of coal will pump as much water or shovel as much sand as the +average man will pump or shovel in a lifetime; so that if a man +proposes to do nothing but work with his muscles, he had better dig +three tons of coal and set that to do his work and then die, because +his work will be better done, and without any cost for the +maintenance of the doer. + +Come down below the color vibrations, and we shall find that those +which are too infrequent to be visible, manifest as heat. Naturally +there will be as many different kinds of heat as tints of color, +because there is as great a range of numbers of vibration. It is +our privilege to sift them apart and sort them over, and find what +kinds are best adapted to our various uses. + +Take an electric lamp, giving a strong beam of light and heat, and +with a plano-convex lens gather it into a single beam and direct +it upon a thermometer, twenty feet away, that is made of glass +and filled with air. The [Page 32] expansion or contraction of this +air will indicate the varying amounts of heat. Watch your +air-thermometer, on which the beam of heat is pouring, for the +result. There is none. And yet there is a strong current of heat +there. Put another kind of test of heat beyond it and it appears; +coat the air-thermometer with a bit of black cloth, and that will +absorb heat and reveal it. But why not at first? Because the glass +lens stops all the heat that can affect glass. The twenty feet of +air absorbs all the heat that affects air, and no kind of heat is +left to affect an instrument made of glass and air; but there are +kinds of heat enough to affect instruments made of other things. + +A very strong current of heat may be sent right through the heart +of a block of ice without melting the ice at all or cooling off +the heat in the least. It is done in this way: Send the beam of +heat through water in a glass trough, and this absorbs all the heat +that can affect water or ice, getting itself hot, and leaving all +other kinds of heat to go through the ice beyond; and appropriate +tests show that as much heat comes out on the other side as goes +in on this side, and it does not melt the ice at all. Gunpowder +may be exploded by heat sent through ice. Dr. Kane, years ago, +made this experiment. He was coming down from the north, and fell +in with some Esquimaux, whom he was anxious to conciliate. He said +to the old wizard of the tribe, "I am a wizard; I can bring the +sun down out of the heavens with a piece of ice." That was a good, +deal to say in a country where there was so little sun. "So," he +writes, "I took my hatchet, chipped a small piece of ice into the +form of a double-convex lens, [Page 33] smoothed it with my warm +hands, held it up to the sun, and, as the old man was blind, I +kindly burned a blister on the back of his hand to show him I could +do it." + +These are simple illustrations of the various kinds of heat. The +best furnace or stove ever invented consumes fifteen times as much +fuel to produce a given amount of heat as the furnace in our bodies +consumes to produce a similar amount. We lay in our supplies of +carbon at the breakfast, dinner, and supper table, and keep ourselves +warm by economically burning it with the oxygen we breathe. + +Heat associated with light has very different qualities from that +which is not. Sunlight melts ice in the middle, bottom, and top at +once. Ice in the spring-time is honey-combed throughout. A piece +of ice set in the summer sunshine crumbles into separate crystals. +Dark heat only melts the surface. + +Nearly all the heat of the sun passes through glass without hinderance; +but take heat from white-hot platinum and only seventy-six per cent. +of it goes through glass, twenty-four per cent. being so constituted +that it cannot pass with facility. Of heat from copper at 752° +only six per cent. can go through glass, the other ninety-four per +cent. being absorbed by it. + +The heat of the sun beam goes through glass without [Page 34] any +hinderance whatever. It streams into the room as freely as if there +were no glass there. But what if the furnace or stove heat went +through glass with equal facility? We might as well try to heat our +rooms with the window-panes all out, and the blast of winter +sweeping through them. + +The heat of the sun, by its intense vibrations, comes to the earth +dowered with a power which pierces the miles of our atmosphere, +but if our air were as pervious to the heat of the earth, this +heat would flyaway every night, and our temperature would go down +to 200° below zero. This heat comes with the light, and then, +dissociated from it, the number of its vibrations lessened, it is +robbed of its power to get away, and remains to work its beneficent +ends for our good. + +Worlds that are so distant as to receive only 1/1000 of the heat +we enjoy, may have atmospheres that retain it all. Indeed it is +probable that Mars, that receives but one-quarter as much heat +as the earth, has a temperature as high as ours. The poet drew on +his imagination when he wrote: + + "Who there inhabit must have other powers, + Juices, and veins, and sense and life than ours; + One moment's cold like theirs would pierce the bone, + Freeze the heart's-blood, and turn us all to stone." + +The power that journeys along the celestial spaces in the flashing +sunshine is beyond our comprehension. It accomplishes with ease +what man strives in vain to do with all his strength. At West Point +there are some links of a chain that was stretched across the river +to prevent British ships from ascending; these links were made +of two-and-a-quarter-inch iron. A powerful locomotive might tug +in vain at one of them and not stretch it the thousandth part of +an inch. But the heat of a single gas-burner, that glows with the +preserved sunlight of other ages, when suitably applied to the +link, stretches it with ease; such enormous power has a little +heat. There is a certain iron bridge across the Thames at London, +resting on arches. The warm sunshine, acting [Page 35] upon the +iron, stations its particles farther and farther apart. Since the +bottom cannot give way the arches must rise in the middle. As they +become longer they lift the whole bridge, and all the thundering +locomotives and miles of goods-trains cannot bring that bridge down +again until the power of the sunshine has been withdrawn. There is +Bunker Hill Monument, thirty-two feet square at the base, with an +elevation of two hundred and twenty feet. The sunshine of every +summer's day takes hold of that mighty pile of granite with its +aėrial fingers, lengthens the side affected, and bends the whole +great mass as easily as one would bend a whipstock. A few years ago +we hung a plummet from the top of this monument to the bottom. At 9 +A.M. it began to move toward the west; at noon it swung round toward +the north; in the afternoon it went east of where it first was, and +in the night it settled back to its original place. + +The sunshine says to the sea, held in the grasp of gravitation, +"Rise from your bed! Let millions of tons of water fly on the wings +of the viewless air, hundreds of miles to the distant mountains, +and pour there those millions of tons that shall refresh a whole +continent, and shall gather in rivers fitted to bear the commerce +and the navies of nations." Gravitation says, "I will hold every +particle of this ocean as near the centre of the earth as I can." +Sunshine speaks with its word of power, and says, "Up and away!" +And in the wreathing mists of morning these myriads of tons rise +in the air, flyaway hundreds of miles, and supply all the Niagaras, +Mississippis and Amazons of earth. The sun says to the earth, wrapped +in the mantle of winter, [Page 36] "Bloom again;" and the snows +melt, the ice retires, and vegetation breaks forth, birds sing, and +spring is about us. + +Thus it is evident that every force is constitutionally arranged +to be overcome by a higher, and all by the highest. Gravitation of +earth naturally and legitimately yields to the power of the sun's +heat, and then the waters fly into the clouds. It as naturally +and legitimately yields to the power of mind, and the waters of the +Red Sea are divided and stand "upright as an heap." Water naturally +bursts into flame when a bit of potassium is thrown into it, and +as naturally when Elijah calls the right kind of fire from above. +What seems a miracle, and in contravention of law, is only the +constitutional exercise of higher force over forces organized to +be swayed. If law were perfectly rigid, there could be but one +force; but many grades exist from cohesion to mind and spirit. +The highest forces are meant to have victory, and thus give the +highest order and perfectness. + +Across the astronomic spaces reach all these powers, making creation +a perpetual process rather than a single act. It almost seems as +if light, in its varied capacities, were the embodiment of God's +creative power; as if, having said, "Let there be light," he need do +nothing else, but allow it to carry forward the creative processes +to the end of time. It was Newton, one of the earliest and most +acute investigators in this study of light, who said, "I seem to +have wandered on the shore of Truth's great ocean, and to have +gathered a few pebbles more beautiful than common; but the vast +ocean itself rolls before me undiscovered and unexplored." + +[Page 37] +EXPERIMENTS WITH LIGHT. + +A light set in a room is seen from every place; hence light streams +in every possible direction. If put in the centre of a hollow sphere, +every point of the surface will be equally illumined. If put in +a sphere of twice the diameter, the same light will fall on all +the larger surface. The surfaces of spheres are as the squares +of their diameters; hence, in the larger sphere the surface is +illumined only one-quarter as much as the smaller. The same is true +of large and small rooms. In Fig. 7 it is apparent that the light +that falls on the first square is spread, at twice the distance, +over the second square, which is four times as large, and at three +times the distance over nine times the surface. The varying amount +of light received by each planet is also shown in fractions above +each world, the amount received by the earth being 1. + +[Illustration: Fig. 7.] + +[Illustration: Fig. 8.--Measuring Intensities of Light.] + +The intensity of light is easily measured. Let two lights of different +brightness, as in Fig. 8, cast shadows on the same screen. Arrange +them as to distance so that both shadows shall be equally dark. +Let them fall side by side, and study them carefully. Measure the +respective distances. Suppose one is twenty inches, the other forty. +Light varies as the square [Page 38] of the distance: the square of +20 is 400, of 40 is 1600. Divide 1600 by 400, and the result is that +one light is four times as bright as the other. + +[Illustration: Fig. 9.--Reflection and Diffusion of Light.] + +Light can be handled, directed, and bent, as well as iron bars. +Darken a room and admit a beam of sunlight through a shutter, or +a ray of lamp-light through the key-hole. If there is dust in the +room it will be observed that light goes in straight lines. Because +of this men are able to arrange houses and trees in rows, the hunter +aims his rifle correctly, and the astronomer projects straight +lines to infinity. Take a hand-mirror, or better, a piece of glass +coated on one side with black varnish, and you can send your ray +anywhere. By using two mirrors, or having an assistant and using +several, you can cause a ray of light to turn as many corners as you +please. I once saw Mr. Tyndall send a ray into a glass jar filled +with smoke (Fig. 9). Admitting a slender ray through a small hole in +a card over the mouth, one ray appeared; removing the cover, the +whole jar was luminous; as the smoke disappeared in spots cavities +of darkness appeared. Turn the same ray into a tumbler of water, +[Page 39] +it becomes faintly visible; stir into it a teaspoonful of milk, then +turn in the ray of sunlight, and it glows like a lamp, illuminating +the whole room. These experiments show how the straight rays of +the sun are diffused in every direction over the earth. + +Set a small light near one edge of a mirror; then, by putting the +eye near the opposite edge, you see almost as many flames as you +please from the multiplied reflections. How can this be accounted +for? + +Into your beam of sunlight, admitted through a half-inch hole, +put the mirror at an oblique angle; you can arrange it so as to +throw half a dozen bright spots on the opposite wall. + +[Illustration: Fig. 10.--Manifold Reflections.] + +In Fig. 10 the sunbeam enters at A, and, striking the mirror _m_ +at _a_, is partly reflected to 1 on the wall, and partly enters +the glass, passes through to the silvered back at B, and is totally +reflected to _b_, where it again divides, some of it going to the +wall at 2, and the rest, continuing to make the same reflections +and divisions, causes spots 3, 4, 5, etc. The brightest spot is +at No.2, because the silvered glass at B is the best reflector +and has the most light. + +When the discovery of the moons of Mars was announced in 1877, +it was also widely published that they could be seen by a mirror. +Of course this is impossible. The point of light mistaken for the +moon in this secondary reflection was caused by holding the mirror +in an oblique position. + +Take a small piece of mirror, say an inch in surface, and putting +under it three little pellets of wax, putty, or clay, set it on +the wrist, with one of the pellets on the pulse. Hold the mirror +steadily in the beam of light, and the frequency and prominence of +each pulse-beat will be indicated by the tossing spot of light on +the wall. If the operator becomes excited the fact will be evident +to all observers. + +[Illustration: Fig. 11.] + +Place a coin in a basin (Fig. 11), and set it so that the rim will +conceal the coin from the eye. Pour in water, and the coin will +[Page 40] appear to rise into sight. When light passes from a medium +of one density to a medium of another, its direction is changed. +Thus a stick in water seems bent. Ships below the horizon are +sometimes seen above, because of the different density of the layers +of air. + +Thus light coming from the interstellar spaces, and entering our +atmosphere, is bent down more and more by its increasing density. +The effect is greatest when the sun or star is near the horizon, +none at all in the zenith. This brings the object into view before +it is risen. Allowance for this displacement is made in all delicate +astronomical observations. + +[Illustration: Fig. 12.--Atmospherical Refraction.] + +Notice on the floor the shadow of the window-frames. The glass +of almost every window is so bent as to turn the sunlight aside +enough to obliterate some of the shadows or increase their thickness. + +DECOMPOSITION OF LIGHT. + +Admit the sunbeam through a slit one inch long and one-twentieth +of an inch wide. Pass it through a prism. Either purchase one or +make it of three plain pieces of glass one and a half inch wide +by six inches long, fastened together in triangular shape--fasten +the edges with hot wax and fill it with water; then on a screen +or wall you will have the colors of the rainbow, not merely seven +but seventy, if your eyes are sharp enough. + +Take a bit of red paper that matches the red color of the spectrum. +Move it along the line of colors toward the violet. In the orange +it is dark, in the yellow darker, in the green and all beyond, +black. That is because there are no more red rays to be reflected +by it. So a green object is true to its color only in the green +rays, and black elsewhere. All these colors may be recombined by +a second prism into white light. + + + + +[Page 41] +III. + +ASTRONOMICAL INSTRUMENTS. + + "The eyes of the Lord are in every place."--_Proverbs_ xv. 3. + +[Page 42] +"Man, having one kind of an eye given him by his Maker, proceeds +to construct two other kinds. He makes one that magnifies invisible +objects thousands of times, so that a dull razor-edge appears as +thick as three fingers, until the amazing beauty of color and form +in infinitesimal objects is entrancingly apparent, and he knows that +God's care of least things is infinite. Then he makes the other kind +four or six feet in diameter, and penetrates the immensities of space +thousands of times beyond where his natural eye can pierce, until he +sees that God's immensities of worlds are infinite also."--BISHOP +FOSTER. + + + + +[Page 43] +III. + +_THE TELESCOPE._ + +Frequent allusion has been made in the previous chapter to discovered +results. It is necessary to understand more clearly the process by +which such results have been obtained. Some astronomical instruments +are of the simplest character, some most delicate and complex. +When a man smokes a piece of glass, in order to see an eclipse +of the sun, he makes a simple instrument. Ferguson, lying on his +back and slipping beads on a string at a certain distance above +his eye, measured the relative distances of the stars. The use +of more complex instruments commenced when Galileo applied the +telescope to the heavens. He cannot be said to have invented the +telescope, but he certainly constructed his own without a pattern, +and used it to good purpose. It consists of a lens, O B (Fig. 13), +which acts as a multiple prism to bend all the rays to one point +at R. Place the eye there, and it receives as much light as if it +were as large as the lens O B. The rays, however, are convergent, +and the point difficult to [Page 44] find. Hence there is placed at +R a concave lens, passing through which the rays emerge in parallel +lines, and are received by the eye. Opera-glasses are made upon +precisely this principle to-day, because they can be made +conveniently short. + +[Illustration: Fig. 13.--Refracting Telescope.] + +If, instead of a concave lens at R, converting the converging rays +into parallel ones, we place a convex or magnifying lens, the minute +image is enlarged as much as an object seems diminished when the +telescope is reversed. This is the grand principle of the refracting +telescope. Difficulties innumerable arise as we attempt to enlarge +the instruments. These have been overcome, one after another, until +it is now felt that the best modern telescope, with an object lens +of twenty-six inches, has fully reached the limit of optical power. + +_The Reflecting Telescope_. + +This is the only kind of instrument differing radically from the +refracting one already described. It receives the light in a concave +mirror, M (Fig. 14), which reflects it to the focus F, producing the +same result as the lens of the refracting telescope. Here a mirror +may be placed obliquely, reflecting the image at right angles to the +eye, outside the tube, in which case it is called the Newtonian +telescope; or a mirror at R may be placed perpendicularly, and send +the rays through [Page 45] an opening in the mirror at M. This form +is called the Gregorian telescope. Or the mirror M may be slightly +inclined to the coming rays, so as to bring the point F entirely +outside the tube, in which case it is called the Herschelian +telescope. In either case the image may be magnified, as in the +refracting telescope. + +[Illustration: Fig. 14.--Reflecting Telescope.] + +Reflecting telescopes are made of all sizes, up to the Cyclopean +eye of the one constructed by Lord Rosse, which is six feet in +diameter. The form of instrument to be preferred depends on the +use to which it is to be put. The loss of light in passing through +glass lenses is about two-tenths. The loss by reflection is often +one-half. In view of this peculiarity and many others, it is held +that a twenty-six-inch refractor is fully equal to any six-foot +reflector. + +The mounting of large telescopes demands the highest engineering +ability. The whole instrument, with its vast weight of a twenty-six-inch +glass lens, with its accompanying tube and appurtenances, must be +pointed as nicely as a rifle, and held as steadily as the axis +of the globe. To give it the required steadiness, the foundation +on which it is placed is sunk deep in the earth, far from rail or +other roads, and no part of the observatory is allowed to touch +this support. When a star is once found, the earth swiftly rotates +the telescope away from it, and it passes out of the field. To +avoid this, clock-work is so arranged that the great telescope +follows the star by the hour, if required. It will take a star at +its eastern rising, and hold it constantly in view while it climbs +to the meridian and sinks in the west (Fig. 15). The reflector +demands still more difficult engineering. That of Lord Rosse has +a metallic mirror [Page 46] weighing six tons, a tube forty feet +long, which, with its appurtenances, weighs seven tons more. It +moves between two walls only 10° east and west. The new Paris +reflector (Fig. 16) has a much wider range of movement. + +[Illustration: Fig. 15.--Cambridge Equatorial.] + +[Illustration: Fig. 16.--New Paris Reflector.] + +_The Spectroscope._ + +A spectrum is a collection of the colors which are dispersed by +a prism from any given light. If it is sunlight, it is a solar +spectrum; if the source of light is a [Page 49] star, candle, +glowing metal, or gas, it is the spectrum of a star, candle, glowing +metal, or gas. An instrument to see these spectra is called a +spectroscope. Considering the infinite variety of light, and its +easy modification and absorption, we should expect an immense number +of spectra. A mere prism disperses the light so imperfectly that +different orders of vibrations, perceived as colors, are mingled. No +eye can tell where one commences or ends. Such a spectrum is said to +be impure. What we want is that each point in the spectrum should be +made of rays of the same number of vibrations. As we can let only a +small beam of light pass through the prism, in studying celestial +objects with a telescope and spectroscope we must, in every +instance, contract the aperture of the instrument until we get only +a small beam of light. In order to have the colors thoroughly +dispersed, the best instruments pass the beam of light through a +series of prisms called a battery, each one spreading farther the +colors which the previous ones had spread. In Fig. 17 the ray is +seen entering through the telescope A, which renders the rays +parallel, and passing [Page 50] through the prisms out to telescope +B, where the spectrum can be examined on the retina of the eye for a +screen. In order to still farther disperse the rays, some batteries +receive the ray from the last prism at O upon an oblique mirror, +send it up a little to another, which delivers it again to the prism +to make its journey back again through them all, and come out to be +examined just above where it entered the first prism. + +[Illustration: Fig. 17.--Spectroscope, with Battery of Prisms.] + +Attached to the examining telescope is a diamond-ruled scale of glass, +enabling us to fix the position of any line with great exactness. + +[Illustration: Fig. 18.--Spectra of glowing Hydrogen and the Sun.] + +In Fig. 18 is seen, in the lower part, a spectrum of the sun, with +about a score of its thousands of lines made evident. In the upper +part is seen the spectrum of bright lines given by glowing hydrogen +gas. These lines are given by no other known gas; they are its +autograph. It is readily observed that they precisely correspond +with certain dark lines in the solar spectrum. Hence we easily +know that a glowing gas gives the same bright lines that it absorbs +from the light of another source passing through it--that is, glowing +gas gives out the same rays of light that it absorbs when it is +not glowing. + +The subject becomes clearer by a study of the chromolithic plate. +No. 1 represents the solar spectrum, with a few of its lines on an +accurately graduated scale. [Page 51] No.3 shows the bright line of +glowing sodium, and, corresponding to a dark line in the solar +spectrum, shows the presence of salt in that body. No. 2 shows that +potassium has some violet rays, but not all; and there being no dark +line to correspond in the solar spectrum, we infer its absence from +the sun. No.6 shows the numerous lines and bands of barium--several +red, orange, yellow, and four are very bright green ones. The lines +given by any volatilized substances are always in the same place on +the scale. + +A patient study of these signs of substances reveals, richer results +than a study of the cuniform characters engraved on Assyrian slabs; +for one is the handwriting of men, the other the handwriting of +God. + +One of the most difficult and delicate problems solved by the +spectroscope is the approach or departure of a light-giving body +in the line of sight. Stand before a locomotive a mile away, you +cannot tell whether it approaches or recedes, yet it will dash by +in a minute. How can the movements of the stars be comprehended +when they are at such an immeasurable distance? + +It can best be illustrated by music. The note C of the G clef is +made by two hundred and fifty-seven vibrations of air per second. +Twice as many vibrations per second would give us the note C an octave +above. Sound travels at the rate of three hundred and sixty-four +yards per second. If the source of these two hundred and fifty-seven +vibrations could approach us at three hundred and sixty-four yards +per second, it is obvious that twice as many waves would be put +into a given space, and we should hear the upper C when only waves +enough were made for the lower C. The same [Page 52] result would +appear if we carried our ear toward the sound fast enough to take up +twice as many valves as though we stood still. This is apparent to +every observer in a railway train. The whistle of an approaching +locomotive gives one tone; it passes, and we instantly detect +another. Let two trains, running at a speed of thirty-six yards a +second, approach each other. Let the whistle of one sound the note +E, three hundred and twenty-three vibrations per second. It will be +heard on the other as the note G, three hundred and eighty-eight +vibrations per second; for the speed of each train crowds the +vibrations into one-tenth less room, adding 32+ vibrations per +second, making three hundred and eighty-eight in all. The trains +pass. The vibrations are put into one-tenth more space by the +whistle making them, and the other train allows only nine-tenths of +what there are to overtake the ear. Each subtracts 32+ vibrations +from three hundred and twenty-three, leaving only two hundred and +fifty-eight, which is the note C. Yet the note E was constantly +uttered. + +[Illustration: 1. Solar Spectrum. 2. Spectrum of Potassium. 3. +Spectrum of Sodium. 4. Spectrum of Strontium. 5. Spectrum of Calcium. +6. Spectrum of Barium.] + +If a source of light approach or depart, it will have a similar +effect on the light waves. How shall we detect it? If a star approach +us, it puts a greater number of waves into an inch, and shortens their +length. If it recedes, it increases the length of the wave--puts +a less number into an inch. If a body giving only the number of +vibrations we call green were to approach sufficiently fast, it +would crowd in vibrations enough to appear what we call blue, indigo, +or even violet, according to its speed. If it receded sufficiently +fast, it would leave behind it only vibrations enough to fill up +[Page 53] the space with what we call yellow, orange, or red, +according to its speed; yet it would be green, and green only, all +the time. But how detect the change? If red waves are shortened they +become orange in color; and from below the red other rays, too far +apart to be seen by the eye, being shortened, become visible as red, +and we cannot know that anything has taken place. So, if a star +recedes fast enough, violet vibrations being lengthened become +indigo; and from above the violet other rays, too short to be seen, +become lengthened into visible violet, and we can detect no movement +of the colors. The dark lines of the spectrum are the cutting out of +rays of definite wave-lengths. If the color spectrum moves away, +they move with it, and away from their proper place in the ordinary +spectrum. If, then, we find them toward the red end, the star is +receding; if toward the violet end, it is approaching. Turn the +instrument on the centre of the sun. The dark lines take their +appropriate place, and are recognized on the ruled scale. Turn it on +one edge, that is approaching us one and a quarter miles a second by +the revolution of the sun on its axis, the spectral lines move +toward the violet end; turn the spectroscope toward the other edge +of the sun, it is receding from us one and a quarter miles a second +by reason of the axial revolution, and the spectral lines move +toward the red end. Turn it near the spots, and it reveals the +mighty up-rush in one place and the down-rush in another of one +hundred miles a second. We speak of it as an easy matter, but it is +a problem of the greatest delicacy, almost defying the mind of man +to read the movements of matter. + +It should be recognized that Professor Young, of [Page 54] +Princeton, is the most successful operator in this recent realm of +science. He already proposes to correct the former estimate of the +sun's axial revolutions, derived from observing its spots, by the +surer process of observing accelerated and retarded light. + +Within a very few years this wonderful instrument, the spectroscope, +has made amazing discoveries. In chemistry it reveals substances +never known before; in analysis it is delicate to the detection of +the millionth of a grain. It is the most deft handmaid of chemistry, +the arts, of medical science, and astronomy. It tells the chemical +constitution of the sun, the movements taking place, the nature of +comets, and nebulę. By the spectroscope we know that the atmospheres +of Venus and Mars are like our own; that those of Jupiter and Saturn +are very unlike; it tells us which stars approach and which recede, +and just how one star differeth from another in glory and substance. + +In the near future we shall have the brilliant and diversely colored +flowers of the sky as well classified into orders and species as +are the flowers of the earth. + + + + +[Page 55] +IV. + +CELESTIAL MEASUREMENTS. + +"Who hath measured the waters in the hollow of his hand, and meted +out heaven with the span? Mine hand also hath laid the foundation +of the earth, and my right hand hath spanned the heavens."--_Isa._ +xl. 12; xlviii. 13. + +[Page 56] + "Go to yon tower, where busy science plies + Her vast antennę, feeling thro' the skies; + That little vernier, on whose slender lines + The midnight taper trembles as it shines, + A silent index, tracks the planets' march + In all their wanderings thro' the ethereal arch, + Tells through the mist where dazzled Mercury burns, + And marks the spot where Uranus returns. + + "So, till by wrong or negligence effaced, + The living index which thy Maker traced + Repeats the line each starry virtue draws + Through the wide circuit of creation's laws; + Still tracks unchanged the everlasting ray + Where the dark shadows of temptation stray; + But, once defaced, forgets the orbs of light, + And leaves thee wandering o'er the expanse of night." + OLIVER WENDELL HOLMES. + + + + +[Page 57] +IV. + +_CELESTIAL MEASUREMENTS._ + +We know that astronomy has what are called practical uses. If a +ship had been driven by Euroclydon ten times fourteen days and +nights without sun or star appearing, a moment's glance into the +heavens from the heaving deck, by a very slightly educated sailor, +would tell within one hundred yards where he was, and determine +the distance and way to the nearest port. We know that, in all +final and exact surveying, positions must be fixed by the stars. +Earth's landmarks are uncertain and easily removed; those which +we get from the heavens are stable and exact. + +In 1878 the United States steam-ship _Enterprise_ was sent to survey +the Amazon. Every night a "star party" went ashore to fix the exact +latitude and longitude by observations of the stars. Our real landmarks +are not the pillars we rear, but the stars millions of miles away. +All our standards of time are taken from the stars; every railway +train runs by their time to avoid collision; by them all factories +start and stop. Indeed, we are ruled by the stars even more than +the old astrologers imagined. + +Man's finest mechanism, highest thought, and broadest exercise +of the creative faculty have been inspired by astronomy. No other +instruments approximate in delicacy those which explore the heavens; +no other [Page 58] system of thought can draw such vast and certain +conclusions from its premises. "Too low they build who build beneath +the stars;" we should lay our foundations in the skies, and then +build upward. + +We have been placed on the outside of this earth, instead of the +inside, in order that we may look abroad. We are carried about, +through unappreciable distance, at the inconceivable velocity of +one thousand miles a minute, to give us different points of vision. +The earth, on its softly-spinning axle, never jars enough to unnest +a bird or wake a child; hence the foundations of our observatories +are firm, and our measurements exact. Whoever studies astronomy, +under proper guidance and in the right spirit, grows in thought +and feeling, and becomes more appreciative of the Creator. + +_Celestial Movements._ + +Let it not be supposed that a mastery of mathematics and a finished +education are necessary to understand the results of astronomical +research. It took at first the highest power of mind to make the +discoveries that are now laid at the feet of the lowliest. It took +sublime faith, courage, and the results of ages of experience in +navigation, to enable Columbus to discover that path to the New +World which now any little boat can follow. Ages of experience +and genius are stored up in a locomotive, but quite an unlettered +man can drive it. It is the work of genius to render difficult +matters plain, abstruse thoughts clear. + +[Illustration: Fig. 19.] + +A brief explanation of a few terms will make the principles of +world inspection easily understood. Imagine a perfect circle thirty +feet in diameter--that is, create [Page 59] one (Fig. 19). Draw +through it a diameter horizontally, another perpendicularly. The +angles made by the intersecting lines are each said to be ninety +degrees, marked thus °. The arc of a circle included between any two +of the lines is also 90°. Every circle, great or small, is divided +into these 360°. If the sun rose in the east and came to the zenith +at noon, it would have passed 90°. When it set in the west it would +have traversed half the circle, or 180°. In Fig. 20 the angle of the +lines measured on the graduated arc is 10°. The mountain is 10° +high, the world 10° in diameter, the comet moves 10° a day, the +stars are 10° apart. The height of the mountain, the diameter of the +world, the velocity of the comet, and the distance between the +stars, depend on the distance of each from the point of sight. Every +degree is divided into 60 minutes (marked '), and every minute into +60 seconds (marked "). + +[Illustration: Fig. 20.--Illustration of Angles.] + +Imagine yourself inside a perfect sphere one hundred feet in diameter, +with the interior surface above, around, and below studded with +fixed bright points like stars. The familiar constellations of +night might be blazoned there in due proportion. + +If this star-sprent sphere were made to revolve once in twenty-four +hours, all the stars would successively [Page 60] pass in review. +How easily we could measure distances between stars, from a certain +fixed meridian, or the equator! How easily we could tell when any +particular star would culminate! It is as easy to take all these +measurements when our earthly observatory is steadily revolved +within the sphere of circumambient stars. Stars can be mapped as +readily as the streets of a great city. Looking down on it in the +night, one could trace the lines of lighted streets, and judge +something of its extent and regularity. But the few lamps of evening +would suggest little of the greatness of the public buildings, the +magnificent enterprise and commerce of its citizens, or the +intelligence of its scholars. Looking up to the lamps of the +celestial city, one can judge something of its extent and +regularity; but they suggest little of the magnificence of the many +mansions. + +Stars are reckoned as so many degrees, minutes, and seconds from +each other, from the zenith, or from a given meridian, or from the +equator. Thus the stars called the Pointers, in the Great Bear, +are 5° apart; the nearest one is 29° from the Pole Star, which is +39° 56' 29" above the horizon at Philadelphia. In going to England +you creep up toward the north end of the earth, till the Pole Star +is 54° high. It stays near its place among the stars continually, + + "Of whose true-fixed and resting quality + There is no fellow in the firmament." + +_How to Measure._ + +Suppose a telescope, fixed to a mural circle, to revolve on an axis, +as in Fig. 21; point it horizontally at a star; [Page 61] turn it up +perpendicular to another star. Of course the two stars are 90° +apart, and the graduated scale, which is attached to the outer edge +of the circle, shows a revolution of a quarter circle, or 90°, But a +perfect accuracy of measurement must be sought; for to mistake the +breadth of a hair, seen at the distance of one hundred and +twenty-five feet, would cause an error of 3,000,000 miles at the +distance of the sun, and immensely more at the distance of the +stars. The correction of an inaccuracy of no greater magnitude than +that has reduced our estimate of the distance of our sun 3,000,000 +miles. + +[Illustration: Fig. 21.--Mural Circle.] + +Consider the nicety of the work. Suppose the graduated scale to +be thirty feet in circumference. Divided into 360°, each would +be one inch long. Divide each degree into 60', each one is 1/60 +of an inch long. It takes good eyesight to discern it. But each +minute must be [Page 62] divided into 60", and these must not only +be noted, but even tenths and hundredths of seconds must be +discerned. Of course they are not seen by the naked eye; some +mechanical contrivance must be called in to assist. A watch loses +two minutes a week, and hence is unreliable. It is taken to a +watch-maker that every single second may be quickened 1/20160 part +of itself. Now 1/20000 part of a second would be a small interval of +time to measure, but it must be under control. If the temperature of +a summer morning rises ten or twenty degrees we scarcely notice it; +but the magnetic tastimeter measures 1/5000 of a degree. + +Come to earthly matters. In 1874, after nearly twenty-eight years' +work, the State of Massachusetts opened a tunnel nearly five miles +long through the Hoosac Mountains. In the early part of the work +the engineers sunk a shaft near the middle 1028 feet deep. Then the +question to be settled was where to go so as to meet the approaching +excavations from the east and west. A compass could not be relied +on under a mountain. The line must be mechanically fixed. A little +divergence at the starting-point would become so great, miles away, +that the excavations might pass each other without meeting; the +grade must also rise toward the central shaft, and fall in working +away from it; but the lines were fixed with such infinitesimal +accuracy that, when the one going west from the eastern portal and +the one going east from the shaft met in the heart of the mountain, +the western line was only one-eighth of an inch too high, and +three-sixteenths of an inch too far north. To reach this perfect +result they had to triangulate from the eastern portal to distant +[Page 63] mountain peaks, and thence down the valley to the central +shaft, and thus fix the direction of the proposed line across the +mouth of the shaft. Plumb-lines were then dropped one thousand and +twenty-eight feet, and thus the line at the bottom was fixed. + +Three attempts were made--in 1867, 1870, and 1872--to fix the exact +time-distance between Greenwich and Washington. These three separate +efforts do not differ one-tenth of a second. Such demonstrable results +on earth greatly increase our confidence in similar measurements +in the skies. + +[Illustration: Fig. 22.] + +A scale is frequently affixed to a pocket-rule, by which we can +easily measure one-hundredth of an inch (Fig. 22). The upper and +lower line is divided into tenths of an inch. Observe the slanting +line at the right hand. It leans from the perpendicular one-tenth +of an inch, as shown by noticing where it reaches the top line. When +it reaches the second horizontal line it has left the perpendicular +one-tenth of that tenth--that is, one-hundredth. The intersection +marks 99/100 of an inch from one end, and one-hundredth from the +other. + +When division-lines, on measures of great nicety, get too fine +to be read by the eye, we use the microscope. By its means we are +able to count 112,000 lines ruled on a glass plate within an inch. +The smallest object that can be seen by a keen eye makes an angle +of 40", but by putting six microscopes on the scale of the telescope +on the mural circle, we are able to reach an exactness of 0".1, or +1/3600 of an inch. This instrument is used to measure the declination +of stars, or angular [Page 64] distance north or south of the +equator. Thus a star's place in two directions is exactly fixed. +When the telescope is mounted on two pillars instead of the face of +a wall, it is called a transit instrument. This is used to determine +the time of transit of a star over the meridian, and if the transit +instrument is provided with a graduated circle it can also be used +for the same purposes as the mural circle. Man's capacity to measure +exactly is indicated in his ascertainment of the length of waves of +light. It is easy to measure the three hundred feet distance between +the crests of storm-waves in the wide Atlantic; easy to measure the +different wave-lengths of the different tones of musical sounds. So +men measure the lengths of the undulations of light. The shortest is +of the violet light, 154.84 ten-millionths of an inch. By the +horizontal pendulum Professor Root has made 1/36000000 of an inch +apparent. + +The next elements of accuracy must be perfect time and perfect +notation of time. As has been said, we get our time from the stars. +Thus the infinite and heavenly dominates the finite and earthly. +Clocks are set to the invariable sidereal time. Sidereal noon is +when we have turned ourselves under the point where the sun crosses +the equator in March, called the vernal equinox. Sidereal clocks +are figured to indicate twenty-four hours in a day: they tick exact +seconds. To map stars we wish to know the exact second when they +cross the meridian, or the north and south line in the celestial +dome above us. The telescope (Fig. 21, p. 61) swings exactly north +and south. In its focus a set of fine threads of spider-lines is +placed (Fig. 23). The telescope is set just high enough, so that +by the rolling over of the earth [Page 65] the star will come into +the field just above the horizontal thread. The observer notes the +exact second and tenth of a second when the star reaches each +vertical thread in the instrument, adds together the times and +divides by five to get the average, and the exact time is reached. + +[Illustration: Fig. 23.--Transit of a Star noted.] + +But man is not reliable enough to observe and record with sufficient +accuracy. Some, in their excitement, anticipate its positive passage, +and some cannot get their slow mental machinery in motion till +after it has made the transit. Moreover, men fall into a habit of +estimating some numbers of tenths of a second oftener than others. +It will be found that a given observer will say three tenths or +seven tenths oftener than four or eight. He is falling into ruts, +and not trustworthy. General O. M. Mitchel, who had been director +of the Cincinnati Observatory, once told one of his staff-officers +that he was late at an appointment. "Only a few minutes," said the +officer, apologetically. "Sir," said the general, "where I have +been accustomed to work, hundredths of a second are too important +to be neglected." And it is to the rare genius of this astronomer, +and to others, that we owe the mechanical accuracy that we now +attain. The clock is made to mark its seconds on paper wrapped +around a revolving cylinder. Under the observer's fingers is an +electric key. This he can touch at the instant of the transit of +the star [Page 66] over each wire, and thus put his observation on +the same line between the seconds dotted by the clock. Of course +these distances can be measured to minute fractional parts of a +second. + +But it has been found that it takes an appreciable time for every +observer to get a thing into his head and out of his finger-ends, +and it takes some observers longer than others. A dozen men, seeing +an electric spark, are liable to bring down their recording marks +in a dozen different places on the revolving paper. Hence the time +that it takes for each man to get a thing into his head and out +of his fingers is ascertained. This time is called his personal +equation, and is subtracted from all of his observations in order to +get at the true time; so willing are men to be exact about material +matters. Can it be thought that moral and spiritual matters have +no precision? Thus distances east or west from any given star or +meridian are secured; those north and south from the equator or +the zenith are as easily fixed, and thus we make such accurate +maps of the heavens that any movements in the far-off stars--so +far that it may take centuries to render the swiftest movements +appreciable--may at length be recognized and accounted for. + +[Illustration: Fig. 24.] + +We now come to a little study of the modes of measuring distances. +Create a perfect square (Fig. 24); draw a diagonal line. The square +angles are 90°, the divided angles give two of 45° each. Now the +base A B is equal to the perpendicular A C. Now any point--C, where +a perpendicular, A C, and a diagonal, B C, meet--will be [Page 67] +as far from A as B is. It makes no difference if a river flows +between A and C, and we cannot go over it; we can measure its +distance as easily as if we could. Set a table four feet by eight +out-doors (Fig. 25); so arrange it that, looking along one end, the +line of sight just strikes a tree the other side of the river. Go to +the other end, and, looking toward the tree, you find the line of +sight to the tree falls an inch from the end of the table on the +farther side. The lines, therefore, approach each other one inch in +every four feet, and will come together at a tree three hundred and +eighty-four feet away. + +[Illustration: Fig. 25.--Measuring Distances.] + +[Illustration: Fig. 26.--Measuring Elevations.] + +The next process is to measure the height or magnitude of objects +at an ascertained distance. Put two pins in a stick half an inch +apart (Fig. 26). Hold it up two feet from the eye, and let the +upper pin fall in line with your eye and the top of a distant church +steeple, and the lower pin in line with the bottom of the church and +your eye. If the church is three-fourths of a mile away, it must +be eighty-two feet high; if a mile away, it must be one hundred +and ten feet high. For if two lines spread [Page 68] one-half an +inch going two feet, in going four feet they will spread an inch, +and in going a mile, or five thousand two hundred and eighty feet, +they will spread out one-fourth as many inches, viz., thirteen +hundred and twenty--that is, one hundred and ten feet. Of course +these are not exact methods of measurement, and would not be correct +to a hair at one hundred and twenty-five feet, but they perfectly +illustrate the true methods of measurement. + +Imagine a base line ten inches long. At each end erect a perpendicular +line. If they are carried to infinity they will never meet: will +be forever ten inches apart. But at the distance of a foot from +the base line incline one line toward the other 63/10000000 of +an inch, and the lines will come together at a distance of three +hundred miles. That new angle differs from the former right angle +almost infinitesimally, but it may be measured. Its value is about +three-tenths of a second. If we lengthen the base line from ten +inches to all the miles we can command, of course the point of +meeting will be proportionally more distant. The angle made by +the lines where they come together will be obviously the same as +the angle of divergence from a right angle at this end. That angle +is called the parallax of any body, and is the angle that would +be made by two lines coming from that body to the two ends of any +conventional base, as the semi-diameter of the earth. That that +angle would vary according to the various distances is easily seen +by Fig. 27. + +[Illustration: Fig. 27.] + +Let O P be the base. This would subtend a greater angle seen from +star A than from star B. Let B be far enough away, and O P would +become invisible, and B [Page 69] would have no parallax for that +base. Thus the moon has a parallax of 57" with the semi-equatorial +diameter of the earth for a base. And the sun has a parallax 8".85 +on the same base. It is not necessary to confine ourselves to right +angles in these measurements, for the same principles hold true in +any angles. Now, suppose two observers on the equator should look at +the moon at the same instant. One is on the top of Cotopaxi, on the +west coast of South America, and one on the west coast of Africa. +They are 90° apart--half the earth's diameter between them. The one +on Cotopaxi sees it exactly overhead, at an angle of 90° with the +earth's diameter. The one on the coast of Africa sees its angle with +the same line to be 89° 59' 3"--that is, its parallax is 57". Try +the same experiment on the sun farther away, as is seen in Fig. 27, +and its smaller parallax is found to be only 8".85. + +It is not necessary for two observers to actually station themselves +at two distant parts of the earth in order to determine a parallax. +If an observer could go from one end of the base-line to the other, +he could determine both angles. Every observer is actually carried +along through space by two motions: one is that of the earth's +revolution of one thousand miles an hour around the axis; and the +other is the movement of the earth around the sun of one thousand +miles in a minute. Hence we can have the diameter not only of [Page +70] the earth (eight thousand miles) for a base-line, but the +diameter of the earth's orbit (184,000,000 miles), or any part of +it, for such a base. Two observers at the ends of the earth's +diameter, looking at a star at the same instant, would find that it +made the same angle at both ends; it has no parallax on so short a +base. We must seek a longer one. Observe a certain star on the 21st +of March; then let us traverse the realms of space for six months, +at one thousand miles a minute. We come round in our orbit to a +point opposite where we were six months ago, with 184,000,000 of +miles between the points. Now, with this for a base-line, measure +the angles of the same stars: it is the same angle. Sitting in my +study here, I glance out of the window and discern separate bricks, +in houses five hundred feet away, with my unaided eye; they subtend +a discernible angle. But one thousand feet away I cannot distinguish +individual bricks; their width, being only two inches, does not +subtend an angle apprehensible to my vision. So at these distant +stars the earth's enormous orbit, if lying like a blazing ring in +space, with the world set on its edge like a pearl, and the sun +blazing like a diamond in the centre, would all shrink to a mere +point. Not quite to a point from the nearest stars, or we should +never be able to measure the distance of any of them. Professor Airy +says that our orbit, seen from the nearest star, would be the same +as a circle six-tenths of an inch in diameter seen at the distance +of a mile: it would all be hidden by a thread one-twenty-fifth of an +inch in diameter, held six hundred and fifty feet from the eye. If a +straight line could be drawn from a star, Sirius in the east to the +star Vega in the west, touching our [Page 71] earth's orbit on one +side, as T R A (Fig. 28), and a line were to be drawn six months +later from the same stars, touching our earth's orbit on the other +side, as R B T, such a line would not diverge sufficiently from a +straight line for us to detect its divergence. Numerous vain +attempts had been made, up to the year 1835, to detect and measure +the angle of parallax by which we could rescue some one or more of +the stars from the inconceivable depths of space, and ascertain +their distance from us. We are ever impelled to triumph over what is +declared to be unconquerable. There are peaks in the Alps no man has +ever climbed. They are assaulted every year by men zealous of more +worlds to conquer. So these greater heights of the heavens have been +assaulted, till some ambitious spirits have outsoared even +imagination by the certainties of mathematics. + +[Illustration: Fig. 28.] + +It is obvious that if one star were three times as far from us as +another, the nearer one would seem to be displaced by our movement +in our orbit three times as much as the other; so, by comparing one +star with another, we reach a ground of judgment. The ascertainment +of longitude at sea by means of the moon affords a good illustration. +Along the track where the moon sails, nine bright stars, four planets, +and the sun have been selected. The nautical almanacs give the +distance of the moon from these successive stars every hour in +the night for three years in advance. The sailor can measure the +distance at any time by his sextant. Looking from the world at +D (Fig. 29), the distance of the moon and [Page 72] star is A E, +which is given in the almanac. Looking from C, the distance is only +B E, which enables even the uneducated sailor to find the distance, +C D, on the earth, or his distance from Greenwich. + +[Illustration: Fig. 29.--Mode of Ascertaining Longitude.] + +So, by comparisons of the near and far stars, the approximate distance +of a few of them has been determined. The nearest one is the brightest +star in the Centaur, never visible in our northern latitudes, which +has a parallax of about one second. The next nearest is No. 61 in +the Swan, or 61 Cygni, having a parallax of 0".34. Approximate +measurements have been made on Sirius, Capella, the Pole Star, +etc., about eighteen in all. The distances are immense: only the +swiftest agents can traverse them. If our earth were suddenly to +dissolve its allegiance to the king of day, and attempt a flight +to the North Star, and should maintain its flight of one thousand +miles a minute, it would flyaway toward Polaris for thousands upon +thousands of years, till a million years had passed away, before +it reached that northern dome of the distant sky, and gave its +new allegiance to another sun. The sun it had left behind it would +gradually diminish till it was small as Arcturus, then small as +could be discerned by the naked eye, until at last it would finally +fade out in utter darkness long before the new sun was reached. +Light can traverse the distance around our earth eight times in +one second. It comes in eight minutes from the sun, but it takes +three and a quarter years to come from Alpha [Page 73] Centauri, +seven and a quarter years from 61 Cygni, and forty-five years from +the Polar Star. + +Sometimes it happens that men steer along a lee shore, dependent +for direction on Polaris, that light-house in the sky. Sometimes it +has happened that men have traversed great swamps by night when that +star was the light-housse of freedom. In either case the exigency +of life and liberty was provided for forty-five years before by a +Providence that is divine. + +We do not attempt to name in miles these enormous distances; we +must seek another yard-stick. Our astronomical unit and standard of +measurement is the distance of the earth from the sun--92,500,000 +miles. This is the golden reed with which we measure the celestial +city. Thus, by laying down our astronomical unit 226,000 times, we +measure to Alpha Centauri, more than twenty millions of millions +of miles. Doubtless other suns are as far from Alpha Centauri and +each other as that is from ours. + +Stars are not near or far according to their brightness. 61 Cygni is +a telescopic star, while Sirius, the brightest star in the heavens, +is twice as far away from us. One star differs from another star +in intrinsic glory. + +The highest testimonies to the accuracy of these celestial observations +are found in the perfect predictions of eclipses, transits of planets +over the sun, occultation of stars by the moon, and those statements +of the Nautical Almanac that enable the sailor to know exactly +where he is on the pathless ocean by the telling of the stars: +"On the trackless ocean this book is the mariner's trusted friend +and counsellor; daily and nightly its revelations bring safety +to ships in all parts of the [Page 74] world. It is something more +than a mere book; it is an ever-present manifestation of the order +and harmony of the universe." + +Another example of this wonderful accuracy is found in tracing +the asteroids. Within 200,000,000 or 300,000,000 miles from the +sun, the one hundred and ninety-two minute bodies that have been +already discovered move in paths very nearly the same--indeed two of +them traverse the same orbit, being one hundred and eighty degrees +apart;--they look alike, yet the eye of man in a few observations +so determines the curve of each orbit, that one is never mistaken +for another. But astronomy has higher uses than fixing time, +establishing landmarks, and guiding the sailor. It greatly quickens +and enlarges thought, excites a desire to know, leads to the utmost +exactness, and ministers to adoration and love of the Maker of +the innumerable suns. + + + + +[Page 75] +V. + +THE SUN. + +"And God made two great lights; the greater light to rule the day, and +the lesser light to rule the night: he made the stars also."--_Gen._ +i. 16. + +[Page 76] +"It is perceived that the sun of the world, with all its essence, +which is heat and light, flows into every tree, and into every +shrub and flower, and into every stone, mean as well as precious; +and that every object takes its portion from this common influx, +and that the sun does not divide its light and heat, and dispense +a part to this and a part to that. It is similar with the sun of +heaven, from which the Divine love proceeds as heat, and the Divine +wisdom as light; these two flow into human minds, as the heat and +light of the sun of the world into bodies, and vivify them according +to the quality of the minds, each of which takes from the common +influx as much as is necessary."--SWEDENBORG. + + + + +[Page 77] +V. + +_THE SUN._ + +Suppose we had stood on the dome of Boston Statehouse November 9th, +1872, on the night of the great conflagration, and seen the fire +break out; seen the engines dash through the streets, tracking their +path by their sparks; seen the fire encompass a whole block, leap +the streets on every side, surge like the billows of a storm-swept +sea; seen great masses of inflammable gas rise like dark clouds +from an explosion, then take fire in the air, and, cut off from +the fire below, float like argosies of flame in space. Suppose we +had felt the wind that came surging from all points of the compass +to fan that conflagration till it was light enough a mile away to +see to read the finest print, hot enough to decompose the torrents +of water that were dashed on it, making new fuel to feed the flame. +Suppose we had seen this spreading fire seize on the whole city, +extend to its environs, and, feeding itself on the very soil, lick +up Worcester with its tongues of flame--Albany, New York, Chicago, +St. Louis, Cincinnati--and crossing the plains swifter than a prairie +fire, making each peak of the Rocky Mountains hold up aloft a separate +torch of flame, and the Sierras whiter with heat than they ever were +with snow, the waters of the Pacific resolve into their constituent +elements of oxygen and hydrogen, and [Page 78] burn with +unquenchable fire! We withdraw into the air, and see below a world +on fire. All the prisoned powers have burst into intensest activity. +Quiet breezes have become furious tempests. Look around this flaming +globe--on fire above, below, around--there is nothing but fire. Let +it roll beneath us till Boston comes round again. No ember has yet +cooled, no spire of flame has shortened, no surging cloud has been +quieted. Not only are the mountains still in flame, but other ranges +burst up out of the seething sea. There is no place of rest, no +place not tossing with raging flame! Yet all this is only a feeble +figure of the great burning sun. It is but the merest hint, a +million times too insignificant. + +The sun appears small and quiet to us because we are so far away. +Seen from the various planets, the relative size of the sun appears +as in Fig. 30. Looked for from some of the stars about us, the +sun could not be seen at all. Indeed, seen from the earth, it is +not always the same size, because the distance is not always the +same. If we represent the size of the sun by one thousand on the +23d of September or 21st of March, it would be represented by nine +hundred and sixty-seven on the 1st of July, and by one thousand +and thirty-four on the 1st of January. + +[Illustration: Fig. 30.--Relative Size of Sun as seen from Different +Planets.] + +We sometimes speak of the sun as having a diameter of 860,000 miles. +We mean that that is the extent of the body as soon by the eye. +But that is a small part of its real diameter. So we say the earth +has an equatorial diameter of 7925-1/2 miles, and a polar one of +7899. But the air is as much a part of the earth as the rocks are. +The electric currents are as much a part of the [Page 79] earth as +the ores and mountains they traverse. What the diameter of the earth +is, including these, no man can tell. We used to say the air +extended forty-five miles, but we now know that it reaches vastly +farther. So of the sun, we might almost say that its diameter is +infinite, for its light and heat reach beyond our measurement. Its +living, throbbing heart sends out pulsations, keeping all space full +of its tides of living light. + +[Page 80] +[Illustration: Fig. 31.--Zodiacal Light.] + +We might say with evident truth that the far-off planets are a +part of the sun, since the space they traverse is filled with the +power of that controlling king; not only with light, but also with +gravitating power. + +But come to more ponderable matters. If we look [Page 81] into our +western sky soon after sunset, on a clear, moonless night in March +or April, we shall see a dim, soft light, somewhat like the +milky-way, often reaching, well defined, to the Pleiades. It is +wedge-shaped, inclined to the south, and the smallest star can +easily be seen through it. Mairan and Cassini affirm that they have +seen sudden sparkles and movements of light in it. All our best +tests show the spectrum of this light to be continuous, and +therefore reflected; which indicates that it is a ring of small +masses of meteoric matter surrounding the sun, revolving with it and +reflecting its light. One bit of stone as large as the end of one's +thumb, in a cubic mile, would be enough to reflect what light we see +looking through millions of miles of it. Perhaps an eye sufficiently +keen and far away would see the sun surrounded by a luminous disk, +as Saturn is with his rings. As it extends beyond the earth's orbit, +if this be measured as a part of the sun, its diameter would be +about 200,000,000 miles. + +Come closer. When the sun is covered by the disk of the moon at +the instant of total eclipse, observers are startled by strange +swaying luminous banners, ghostly and weird, shooting in changeful +play about the central darkness (Fig. 32). These form the corona. +Men have usually been too much moved to describe them, and have +always been incapable of drawing them in the short minute or two +of their continuance. But in 1878 men travelled eight thousand +miles, coming and returning, in order that they might note the +three minutes of total eclipse in Colorado. Each man had his work +assigned to him, and he was drilled to attend to that and nothing +else. Improved instruments were put into his [Page 82] hands, so +that the sun was made to do his own drawing and give his own picture +at consecutive instants. Fig. 33 is a copy of a photograph of the +corona of 1878, by Mr. Henry Draper. It showed much less +changeability that year than common, it being very near the time of +least sun-spot. The previous picture was taken near the time of +maximum sun-spot. + +[Illustration: Fig. 32.--The Corona in 1858, Brazil.] + +It was then settled that the corona consists of reflected light, +sent to us from dust particles or meteoroids swirling in the vast +seas, giving new densities and [Page 83] rarities, and hence this +changeful light. Whether they are there by constant projection, and +fall again to the sun, or are held by electric influence, or by +force of orbital revolution, we do not know. That the corona cannot +be in any sense an atmosphere of any continuous gas, is seen from +the fact that the comet of 1843, passing within 93,000 miles of the +body of the sun, was not burned out of existence as a comet, nor in +any perceptible degree retarded in its motion. If the sun's diameter +is to include the corona, it will be from 1,260,000 to 1,460,000 +miles. + +[Illustration: Fig. 33.--The Corolla in 1878, Colorado.] + [Page 84] Come closer still. At the instant of the totality of the + eclipse red flames of most fantastic shape play along the edge of + the moon's disk. They can be seen at any time by the use of a + proper telescope with a spectroscope attached. I have seen them + with great distinctness and brilliancy with the excellent + eleven-inch telescope of the Wesleyan University. A description of + their appearance is best given in the language of Professor Young, + of Princeton College, who has made these flames the object of most + successful study. On September 7th, 1871, he was observing a large + hydrogen cloud by the sun's edge. This cloud was about 100,000 + miles long, and its upper side was some 50,000 miles above the + sun's surface, the lower side some 15,000 miles. The whole had the + appearance of being supported on pillars of fire, these seeming + pillars being in reality hydrogen jets brighter and more active + than the substance of the cloud. At half-past twelve, when + Professor Young chanced to be called away from his observatory, + there were no indications of any approaching change, except that + one of the connecting stems of the southern extremity of the cloud + had grown considerably brighter and more curiously bent to one + side; and near the base of another, at the northern end, a little + brilliant lump had developed itself, shaped much like a summer + thunderhead. + +[Illustration: Fig. 34.--Solar Prominences of Flaming Hydrogen.] + +But when Professor Young returned, about half an hour later, he +found that a very wonderful change had taken place, and that a +very remarkable process was actually in progress. "The whole thing +had been literally blown to shreds," he says, "by some inconceivable +uprush from beneath. In place of the quiet cloud I had [Page 87] +left, the air--if I may use the expression--was filled with the +flying _débris_, a mass of detached vertical fusi-form fragments, +each from ten to thirty seconds (_i. e._, from four thousand five +hundred to thirteen thousand five hundred miles) long, by two or +three seconds (nine hundred to thirteen hundred and fifty miles) +wide--brighter, and closer together where the pillars had formerly +stood, and rapidly ascending. When I looked, some of them had +already reached a height of nearly four minutes (100,000 miles); and +while I watched them they arose with a motion almost perceptible to +the eye, until, in ten minutes, the uppermost were more than 200,000 +miles above the solar surface. This was ascertained by careful +measurements, the mean of three closely accordant determinations +giving 210,000 miles as the extreme altitude attained. I am +particular in the statement, because, so far as I know, +chromatospheric matter (red hydrogen in this case) has never before +been observed at any altitude exceeding five minutes, or 135,000 +miles. The velocity of ascent, also--one hundred and sixty-seven +miles per second--is considerably greater than anything hitherto +recorded. * * * As the filaments arose, they gradually faded away +like a dissolving cloud, and at a quarter past one only a few filmy +wisps, with some brighter streamers low down near the +chromatosphere, remained to mark the place. But in the mean while +the little 'thunder-head' before alluded to had grown and developed +wonderfully into a mass of rolling and ever-changing flame, to speak +according to appearances. First, it was crowded down, as it were, +along the solar surface; later, it arose almost pyramidally 50,000 +miles in height; then [Page 88] its summit was drawn down into long +filaments and threads, which were most curiously rolled backward and +forward, like the volutes of an Ionic capital, and finally faded +away, and by half-past two had vanished like the other. The whole +phenomenon suggested most forcibly the idea of an explosion under +the great prominence, acting mainly upward, but also in all +directions outward; and then, after an interval, followed by a +corresponding in-rush." + +No language can convey nor mind conceive an idea of the fierce +commotion we here contemplate. If we call these movements hurricanes, +we must remember that what we use as a figure moves but one hundred +miles an hour, while these move one hundred miles a second. Such +storms of fire on earth, "coming down upon us from the north, would, +in thirty seconds after they had crossed the St. Lawrence, be in +the Gulf of Mexico, carrying with them the whole surface of the +continent in a mass not simply of ruins but of glowing vapor, in +which the vapors arising from the dissolution of the materials +composing the cities of Boston, New York, and Chicago would be +mixed in a single indistinguishable cloud." In the presence of +these evident visions of an actual body in furious flame, we need +hesitate no longer in accepting as true the words of St. Peter +of the time "in which the [atmospheric] heavens shall pass away +with a great noise, and the elements shall melt with fervent heat; +the earth also, and the works that are therein, shall be burned +up." + +This region of discontinuous flame below the corona is called the +chromosphere. Hydrogen is the principal material of its upper part; +iron, magnesium, and other [Page 89] metals, some of them as yet +unknown on earth, but having a record in the spectrum, in the denser +parts below. If these fierce fires are a part of the Sun, as they +assuredly are, its diameter would be from 1,060,000 to 1,260,000 +miles. + +Let us approach even nearer. We see a clearly recognized even disk, +of equal dimensions in every direction. This is the photosphere. +We here reach some definitely measurable data for estimating its +visible size. We already know its distance. Its disk subtends an +angle of 32' 12".6, or a little more than half a degree. Three +hundred and sixty such suns, laid side by side, would span the +celestial arch from east to west with a half circle of light. Two +lines drawn from our earth at the angle mentioned would be 860,000 +miles apart at the distance of 92,500,000 miles. This, then, is +the diameter of the visible and measurable part of the sun. It +would require one hundred and eight globes like the earth in a line +to measure the sun's diameter, and three hundred and thirty-nine, +to be strung like the beads of a necklace, to encircle his waist. +The sun has a volume equal to 1,245,000 earths, but being only +one-quarter as dense, it has a mass of only 326,800 earths. It +has seven hundred times the mass of all the planets, asteroids, +and satellites put together. Thus it is able to control them all +by its greater power of attraction. + +Concerning the condition of the surface of the sun many opinions +are held. That it is hot beyond all estimate is indubitable. Whether +solid or gaseous we are not sure. Opinions differ: some incline to +the first theory, others to the second; some deem the sun composed +of solid particles, floating in gas so condensed [Page 90] by +pressure and attraction as to shine like a solid. It has no sensible +changes of general level, but has prodigious activity in spots. +These spots have been the objects of earnest and almost hourly study +on the part of such men as Secchi, Lockyer, Faye, Young, and others, +for years. But it is a long way off to study an object. No telescope +brings it nearer than 200,000 miles. Theory after theory has been +advanced, each one satisfactory in some points, none in all. The +facts about the spots are these: They are most abundant on the two +sides of the equator. They are gregarious, depressed below the +surface, of vast extent, black in the centre, usually surrounded by +a region of partial darkness, beyond which is excessive light. They +have motion of their own over the surface--motion rotating about an +axis, upward and downward about the edges. They change their +apparent shape as the sun carries them across its disk by axial +revolution, being narrow as they present their edges to us, and +rounder as we look perpendicularly into them (Fig. 35). + +[Illustration: Fig. 35.--Change in Spots as rotated across the Disk, +showing Cavities.] + +These spots are also very variable in number, sometimes there being +none for nearly two hundred days, and again whole years during which +the sun is never without them. The period from minimum to maximum +[Page 91] of spots is about eleven years. We might look for them +again and again in vain this year (1878). They will be most numerous +in 1882 and 1893. The cause of this periodicity was inferred to be +the near approach of the enormous planet Jupiter, causing +disturbance by its attraction. But the periods do not correspond, +and the cause is the result of some law of solar action to us as yet +unknown. + +These spots may be seen with almost any telescope, the eye being +protected by deeply colored glasses. + +Until within one hundred years they were supposed to be islands of +scorię floating in the sea of molten matter. But they were depressed +below the surface, and showed a notch when on the edge. Wilson +originated and Herschel developed the theory that the sun's real +body was dark, cool, and habitable, and that the photosphere was +a luminous stratum at a distance from the real body, with openings +showing the dark spots below. Such a sun would have cooled off in +a week, but would previously have annihilated all life below. + +The solar spots being most abundant on the two sides of the equator, +indicates their cyclonic character; the centre of a cyclone is +rarefied, and therefore colder, and cold on the sun is darkness. +M. Faye says: "Like our cyclones, they are descending, as I have +proved by a special study of these terrestrial phenomena. They +carry down into the depths of the solar mass the cooler materials +of the upper layers, formed principally of hydrogen, and thus produce +in their centre a decided extinction of light and heat as long as +the gyratory movement continues. Finally, the hydrogen set free +at the base of the whirlpool becomes reheated at this [Page 92] +great depth, and rises up tumultuously around the whirlpool, forming +irregular jets, which appear above the chromosphere. These jets +constitute the protuberances. The whirlpools of the sun, like those +on the earth, are of all dimensions, from the scarcely visible pores +to the enormous spots which we see from time to time. They have, +like those of the earth, a marked tendency, first to increase and +then to break up, and thus form a row of spots extending along the +same parallel." + +[Illustration: Fig. 36.--Solar spot, by Langley.] + +A spot of 20,000 miles diameter is quite small; there was one 14,816 +miles across, visible to the naked eye for a week in 1843. This +particular sun-spot somewhat [Page 93] helped the Millerites. On the +day of the eclipse, in 1858, a spot over 107,000 miles in extent was +clearly seen. In such vast tempests, if there were ships built as +large as the whole earth, they would be tossed like autumn leaves in +an ocean storm. + +The revolution of the sun carries a spot across its face in about +fourteen days. After a lapse of as much more time, they often reappear +on the other side, changed but recognizable. They often break ont +or disappear under the eye of the observer. They divide like a +piece of ice dropped on a frozen pond, the pieces sliding off in +every direction, or combine like separate floes driven together +into a pack. Sometimes a spot will last for more than two hundred +days, recognizable through six or eight revolutions. Sometimes +a spot will last only half an hour. + +The velocities indicated by these movements are incredible. An +up-rush and down-rush at the sides has been measured of twenty +miles a second; a side-rush or whirl, of one hundred and twenty +miles a second. These tempests rage from a few days to half a year, +traversing regions so wide that our Indian Ocean, the realm of +storms, is too small to be used for comparison; then, as they cease, +the advancing sides of the spots approach each other at the rate of +20,000 miles an hour; they strike together, and the rising spray +of fire leaps thousands of miles into space. It falls again into the +incandescent surge, rolls over mountains as the sea over pebbles, and +all this for eon after eon without sign of exhaustion or diminution. +All these swift succeeding Himalayas of fire, where one hundred +worlds could be buried, do not usually prevent the sun's appearing +to our far-off eyes as a perfect sphere. + +[Page 94] +_What the Sun does for us._ + +To what end does this enormous power, this central source of power, +exist? That it could keep all these gigantic forces within itself +could not be expected. It is in a system where every atom is made +to affect every other atom, and every world to influence every +other. The Author of all lives only to do good, to send rain on +the just and unjust, to cause his sun to rise on the evil and the +good, and to give his spirit, like a perpetually widening river, +to every man to profit withal. + +The sun reaches his unrelaxing hand of gravitation to every other +world at every instant. The tendency of every world is to fly off +in a straight line. This tendency must be momentarily curbed, and +the planet held in its true curve about the sun. These giant worlds +must be perfectly handled. Their speed, amounting to seventy times +as fast as that of a rifle-ball, must be managed. Each and every +world may be said to be lifted momentarily and swung perpetually +at arm's-length by the power of the sun. + +The sun warms us. It would convey but a small idea of the truth +to state how many hundreds of millions of cubic miles of ice could +be hailed at the sun every second without affecting its heat; but, +if any one has any curiosity to know, it is 287,200,000 cubic miles +of ice per second. + +We journey through space which has a temperature of 200° below +zero; but we live, as it were, in a conservatory, in the midst of +perpetual winter. We are roofed over by the air that treasures the +heat, floored under by strata both absorptive and retentive of heat, +[Page 95] and between the earth and air violets grow and grains +ripen. The sun has a strange chemical power. It kisses the cold +earth, and it blushes with flowers and matures the fruit and grain. +We are feeble creatures, and the sun gives us force. By it the light +winds move one-eighth of a mile an hour, the storm fifty miles, the +hurricane one hundred. The force is as the square of the velocity. +It is by means of the sun that the merchant's white-sailed ships are +blown safely home. So the sun carries off the miasma of the marsh, +the pollution of cities, and then sends the winds to wash and +cleanse themselves in the sea-spray. The water-falls of the earth +turn machinery, and make Lowells and Manchesters possible, because +the sun lifted all that water to the hills. + +Intermingled with these currents of air are the currents of electric +power, all derived from the sun. These have shown their swiftness +and willingness to serve man. The sun's constant force displayed +on the earth is equal to 543,000,000,000 engines of 400-horse power +each, working day and night; and yet the earth receives only +1/21500000000 part of the whole force of the sun. + +Besides all this, the sun, with provident care, has made and given +to us coal. This omnipotent worker has stored away in past ages +an inexhaustible reservoir of his power which man may easily mine +and direct, thus releasing himself from absorbing toil. + +EXPERIMENTS. + +Any one may see the spots on the sun who has a spy-glass. Darken +the room and put the glass through an opening toward the sun, as +shown in Fig. 37. The eye-piece should be drawn out about half +an inch beyond [Page 96] its usual focusing for distant objects. The +farther it is drawn, the nearer must we hold the screen for a +perfect image. + +By holding a paper near the eye-piece, the proper direction of +the instrument may be discovered without injury to the eyes. By +this means the sun can be studied from day to day, and its spots or +the transits of Mercury and Venus shown to any number of spectators. + +[Illustration: Fig. 37.--Holding Telescope to see the Sun's Spots.] + +First covering the eyes with very dark or smoked glasses, erect +a disk of pasteboard four inches in diameter between you and the +sun; close one eye; stand near it, and the whole sun is obscured. +Withdraw from it till the sun's rays just shoot over the edge of +the disk on every side. Measure the distance from the eye to the +disk. You will be able to determine the distance of the sun by +the rule of three: thus, as four inches is to 860,000 miles, so +is distance from eye to disk to distance from disk to the sun. +Take such measurements at sunrise, noon, and sunset, and see the +apparently differing sizes due to refraction. + + + + +[Page 97] +VI. + +THE PLANETS, AS SEEN FROM SPACE. + +"He hangeth the earth upon nothing."--_Job_ xxvi. 7. + +[Page 98] +"Let a power be delegated to a finite spirit equal to the projection +of the most ponderous planet in its orbit, and, from an exhaustless +magazine, let this spirit select his grand central orb. Let him with +puissant arm locate it in space, and, obedient to his mandate, there +let it remain forever fixed. He proceeds to select his planetary +globes, which he is now required to marshal in their appropriate +order of distance from the sun. Heed well this distribution; for +should a single globe be misplaced, the divine harmony is destroyed +forever. Let us admit that finite intelligence may at length determine +the order of combination; the mighty host is arrayed in order. +These worlds, like fiery coursers, stand waiting the command to +fly. But, mighty spirit, heed well the grand step, ponder well +the direction in which thou wilt launch each wailing world; weigh +well the mighty impulse soon to be given, for out of the myriads +of directions, and the myriads of impulsive forces, there comes +but a single combination that will secure the perpetuity of your +complex scheme. In vain does the bewildered finite spirit attempt +to fathom this mighty depth. In vain does it seek to resolve the +stupendous problem. It turns away, and while endued with omnipotent +power, exclaims, 'Give to me infinite wisdom, or relieve me from +the impossible task!'"-0. M. MITCHEL, LL. D. + + + + +[Page 99] +VI. + +_THE PLANETS, AS SEEN FROM SPACE_ + +If we were to go out into space a few millions of miles from either +pole of the sun, and were endowed with wonderful keenness of vision, +we should perceive certain facts, viz: That space is frightfully +dark except when we look directly at some luminous body. There is +no air to bend the light out of its course, no clouds or other +objects to reflect it in a thousand directions. Every star is a +brilliant point, even in perpetual sunshine. The cold is frightful +beyond the endurance of our bodies. There is no sound of voice in +the absence of air, and conversation by means of vocal organs being +impossible, it must be carried on by means of mind communication. +We see below an unrevolving point on the sun that marks its pole. +Ranged round in order are the various planets, each with its axis +pointing in very nearly the same direction. All planets, except +possibly Venus, and all moons except those of Uranus and Neptune, +present their equators to the sun. The direction of orbital and +axial revolution seen from above the North Pole would be opposite +to that of the hands of a watch. + +[Illustration: Fig. 38.--Orbits and Comparative Sizes of the Planets.] + +The speed of this orbital revolution must be proportioned to the +distance from the sun. The attraction of the sun varies inversely +as the square of the distance. [Page 100] It holds a planet with a +certain power; one twice as far off, with one-fourth that power. +This attraction must be counterbalanced by centrifugal force; great +force from great speed when attraction is great, and small from less +[Page 101] speed when attractive power is diminished by distance. +Hence Mercury must go 29.5 miles per second--seventy times as fast +as a rifle-ball that goes two-fifths of a mile in a second--or be +drawn into the sun; while Neptune, seventy-five times as far off, +and hence attracted only 1/5626 as much, must be slowed down to 3.4 +miles a second to prevent its flying away from the feebler +attraction of the sun. The orbital velocity of the various planets +in miles per second is as follows: + + Mercury 29.55 | Jupiter 8.06 + Venus 21.61 | Saturn 5.95 + Earth 18.38 | Uranus 4.20 + Mars 14.99 | Neptune 3.36 + +Hence, while the earth makes one revolution in its year, Mercury +has made over four revolutions, or passed through four years; the +slower Neptune has made only 1/164 of one revolution. + +The time of axial revolution which determines the length of the +day varies with different planets. The periods of the four planets +nearest the sun vary only half an hour from that of the earth, +while the enormous bodies of Jupiter and Saturn revolve in ten +and ten and a quarter hours respectively. This high rate of speed, +and its resultant, centrifugal force, has aided in preventing these +bodies from becoming as dense as they would otherwise be--Jupiter +being only 0.24 as dense as the earth, and Saturn only 0.13. This +extremely rapid revolution produces a great flattening at the poles. +If Jupiter should rotate four times more rapidly than it does, it +could not be held together compactly. As it is, the polar diameter +is five thousand miles less than the equatorial: the difference +in diameters produced by the [Page 102] same cause on the earth, +owing to the slower motion and smaller mass, being only twenty-six +miles. The effect of this will be more specifically treated +hereafter. + +The difference in the size of the planets is very noticeable. If +we represent the sun by a gilded globe two feet in diameter, we +must represent Vulcan and Mercury by mustard-seeds; Venus, by a +pea; Earth, by another; Mars, by one-half the size; Asteroids, by +the motes in a sunbeam; Jupiter, by a small-sized orange; Saturn, +by a smaller one; Uranus, by a cherry; and Neptune, by one a little +larger. + +Apply the principle that attraction is in proportion to the mass, +and a man who weighs one hundred and fifty pounds on the earth +weighs three hundred and ninety-six on Jupiter, and only fifty-eight +on Mars; while on the Asteroids he could play with bowlders for +marbles, hurl hills like Milton's angels, leap into the fifth-story +windows with ease, tumble over precipices without harm, and go +around the little worlds in seven jumps. + +[Illustration: Fig. 39.--Orbit of Earth, showing Parallelism of +Axis and Seasons.] + +The seasons of a planet are caused by the inclination of its axis +to the plane of its orbit. In Fig. 39 the rotating earth is seen +at A, with its northern pole turning in constant sunlight, and +its southern pole in constant darkness; everywhere south of the +equator is more darkness than day, and hence winter. Passing on +to B, the world is seen illuminated equally on each side of the +equator. Every place has its twelve hours' darkness and light at +each revolution. But at C--the axis of the earth always preserving +the same direction--the northern pole is shrouded in continual +gloom. Every place [Page 105] north of the equator gets more +darkness than light, and hence winter. + +The varying inclination of the axes of the different planets gives +a wonderful variety to their seasons. The sun is always nearly +over the equator of Jupiter, and every place has nearly its five +hours day and five hours night. The seasons of Earth, Mars, and +Saturn are so much alike, except in length, that no comment is +necessary. The ice-fields at either pole of Mars are observed to +enlarge and contract, according as it is winter or summer there. +Saturn's seasons are each seven and a half years long. The alternate +darkness and light at the poles is fifteen years long. + +But the seasons of Venus present the greatest anomaly, if its assigned +inclination of axis (75°) can be relied on as correct, which is +doubtful. Its tropic zone extends nearly to the pole, and at the +same time the winter at the other pole reaches the equator. The +short period of this planet causes it to present the south pole to +the sun only one hundred and twelve days after it has been scorching +the one at the north. This gives two winters, springs, summers, and +autumns to the equator in two hundred and twenty-five days. + +If each whirling world should leave behind it a trail of light to +mark its orbit, and our perceptions of form were sufficiently acute, +we should see that these curves of light are not exact circles, but +a little flattened into an ellipse, with the sun always in one +of the foci. Hence each planet is nearer to the sun at one part +of its orbit than another; that point is called the perihelion, +and the farthest point aphelion. This eccentricity of orbit, or +distance of the sun from the centre, is very small. [Page 106] In +the case of Venus it is only .007 of the whole, and in no instance +is it more than .2, viz., that of Mercury. This makes the sun appear +twice as large, bright, and hot as seen and felt on Mercury at its +perihelion than at its aphelion. The earth is 3,236,000 miles nearer +to the sun in our winter than summer. Hence the summer in the +southern hemisphere is more intolerable than in the northern. But +this eccentricity is steadily diminishing at a uniform rate, by +reason of the perturbing influence of the other planets. In the case +of some other planets it is steadily increasing, and, if it were to +go on a sufficient time, might cause frightful extremes of +temperature; but Lalande has shown that there are limits at which it +is said, "Thus far shalt thou go, and no farther." Then a +compensative diminution will follow. + +Conceive a large globe, to represent the sun, floating in a round +pond. The axis will be inclined 7-1/2° to the surface of the water, +one side of the equator be 7-1/2° below the surface, and the other +side the same distance above. Let the half-submerged earth sail +around the sun in an appropriate orbit. The surface of the water +will be the plane of the orbit, and the water that reaches out +to the shore, where the stars would be set, will be the plane of +the ecliptic. It is the plane of the earth's orbit extended to +the stars. + +The orbits of all the planets do not lie in the same plane, but +are differently inclined to the plane of the ecliptic, or the plane +of the earth's orbit. Going out from the sun's equator, so as to +see all the orbits of the planets on the edge, we should see them +inclined to that of the earth, as in Fig. 40. + +[Illustration: Fig. 40.--Inclination of the Planes of Orbits.] + +If the earth, and Saturn, and Pallas were lying in [Page 107] the +same direction from the sun, and the outer bodies were to start in a +direct line for the sun, they would not collide with the earth on +their way; but Saturn would pass 4,000,000 and Pallas 50,000,000 +miles over our heads. From this same cause we do not see Venus and +Mercury make a transit across the disk of the sun at every +revolution. + +[Illustration: Fig. 41.--Inclination of Orbits of Venus and Earth. +Nodal Line, D B.] + +Fig. 41 shows a view of the orbits of the earth and Venus seen +not from the edge but from a position somewhat above. The point E, +where Venus crosses the plane of the earth's orbit, is called the +ascending node. If the earth were at B when Venus is at E, Venus +would be seen on the disk of the sun, making a transit. The same +would be true if the earth were at D, and Venus at the descending +node F. + +This general view of the flying spheres is full of interest. [Page +108] While quivering themselves with thunderous noises, all is +silent about them; earthquakes may be struggling on their surfaces, +but there is no hint of contention in the quiet of space. They are +too distant from one another to exchange signals, except, perhaps, +the fleet of asteroids that sail the azure between Mars and Jupiter. +Some of these come near together, continuing to fill each other's +sky for days with brightness, then one gradually draws ahead. They +have all phases for each other--crescent, half, full, and gibbous. +These hundreds of bodies fill the realm where they are with +inexhaustible variety. Beyond are vast spaces--cold, dark, void of +matter, but full of power. Occasionally a little spark of light +looms up rapidly into a world so huge that a thousand of our earths +could not occupy its vast bulk. It swings its four or eight moons +with perfect skill and infinite strength; but they go by and leave +the silence unbroken, the darkness unlighted for years. +Nevertheless, every part of space is full of power. Nowhere in its +wide orbit can a world find a place; at no time in its eons of +flight can it find an instant when the sun does not hold it in +safety and life. + +_The Outlook from the Earth._ + +If we come in from our wanderings in space and take an outlook from +the earth, we shall observe certain movements, easily interpreted +now that we know the system, but nearly inexplicable to men who +naturally supposed that the earth was the largest, most stable, +and central body in the universe. + +We see, first of all, sun, moon, and stars rise in the east, mount +the heavens, and set in the west. As I [Page 109] revolve in my +pivoted study-chair, and see all sides of the room--library, maps, +photographs, telescope, and windows--I have no suspicion that it is +the room that whirls; but looking out of a car-window in a depot at +another car, one cannot tell which is moving, whether it be his car +or the other. In regard to the world, we have come to feel its +whirl. We have noticed the pyramids of Egypt lifted to hide the sun; +the mountains of Hymettus hurled down, so as to disclose the moon +that was behind them to the watchers on the Acropolis; and the +mighty mountains of Moab removed to reveal the stars of the east. +Train the telescope on any star; it must be moved frequently, or the +world will roll the instrument away from the object. Suspend a +cannon-ball by a fine wire at the equator; set it vibrating north +and south, and it swings all day in precisely the same direction. +But suspend it directly over the north pole, and set it swinging +toward Washington; in six hours after it is swinging toward Rome, in +Italy; in twelve hours, toward Siam, in Asia; in nineteen hours, +toward the Sandwich Islands; and in twenty-four, toward Washington +again, not because it has changed the plane of its vibration, but +because the earth has whirled beneath it, and the torsion of the +wire has not been sufficient to compel the plane of the original +direction to change with the turning of the earth. The law of +inertia keeps it moving in the same direction. The same experimental +proof of revolution is shown in a proportional degree at any point +between the pole and the equator. + +But the watchers on the Acropolis do not get turned over so as to +see the moon at the same time every night. [Page 110] We turn down +our eastern horizon, but we do not find fair Luna at the same moment +we did the night before. We are obliged to roll on for some thirty +to fifty minutes longer before we find the moon. It must be going in +the same direction, and it takes us longer to get round to it than +if if it were always in the same spot; so we notice a star near the +moon one night--it is 13° west of the moon the next night. The moon +is going around the earth from west to east, and if it goes 13° in +one day, it will take a little more than twenty-seven days to go the +entire circle of 360°. + +[Illustration: Fig. 42.--Showing the Sun's Movement among the Stars.] + +[Page 111] +In our outlook we soon observe that we do not by our revolution +come to see the same stars rise at the same hour every night. Orion +and the Pleiades, our familiar friends in the winter heavens, are +gone from the summer sky. Have they fled, or are we turned from +them? This is easily understood from Fig. 42. + +When the observer on the earth at A looks into the midnight sky +he sees the stars at E; but as the earth passes on to B, he sees +those stars at E three minutes sooner every night; and at midnight +the stars at F are over his head. Thus in a year, by going around +the sun, we have every star of the celestial dome in our midnight +sky. We see also how the sun appears among the successive +constellations. When we are at A, we see the sun among the stars +at G; but as we move toward B, the sun appears to move toward H. +If we had observed the sun rise on the 20th of August, 1876, we +should have seen it rise a little before Regulus, and a little +south of it, in such a relation as circle 1 is to the star in Fig. +43. By sunset the earth had moved enough to make the sun appear +to be at circle 2, and by the next morning at circle 3, at which +time Regulus would rise before the sun. Thus the earth's motion +seems to make the sun traverse a regular circle among the stars +once a year: but it is not the sun that moves. + +[Illustration: Fig. 43.] + +There are certain stars that have such irregular, uncertain, vagarious +ways that they were called vagabonds, or planets, by the early +astronomers. Here is the path of Jupiter in the year 1866 (Fig. +44). These bodies go forward for awhile, then stop, start aside, +then retrograde, [Page 112] and go on again. Some are never seen far +from the sun, and others in all parts of the ecliptic. + +[Illustration: Fig. 44.] + +First see them as they stand to-day, as in Fig. 45. The observer +stands on the earth at A. It has rolled over so far that he cannot +see the sun; it has set. But Venus is still in sight; Jupiter is +45° behind Venus, and Saturn is seen 90° farther east. When A has +rolled a little farther, if he is awake, he will see Mars before +he sees the sun; or, in common language, Venus will set after, +and Mars rise before the sun. All these bodies at near and far +distances seem set in the starry dome, as the different stars seem +in Fig. 42, p. 110. + +[Illustration: Fig. 45. Showing Position of Planets.] + +The mysterious movements of advance and retreat are rendered +intelligible by Fig. 46. The planet Mercury is at A, and, seen from +the earth, B is located at _a_, [Page 113] on the background of the +stars it seems to be among. It remains apparently stationary at _a_ +for some time, because approaching the earth in nearly a straight +line. Passing D to C, it appears to retrograde among the stars to +_c_; remains apparently stationary for some time, then, in passing +from C to E and A, appears to pass back among the stars to _a_. The +progress of the earth, meanwhile, although it greatly retards the +apparent motion from A to C, greatly hastens it from C to A. + +[Illustration: Fig. 46.--Apparent Movements of an Inferior Planet.] + +It is also apparent that Mercury and Venus, seen from the earth, +can never appear far from the sun. They must be just behind the +sun as evening stars, or just before it as heralds of the morning. +Venus is never more than 47° from the sun, and Mercury never more +than 30°; indeed, it keeps so near the sun that very few people +have ever seen the brilliant sparkler. Observe how much larger the +planet appears near the earth in conjunction at D than in opposition +at E. Observe also what phases it must present, and how transits +sometimes take place. + +[Page 114] +The movement of a superior planet, one whose orbit is exterior +to the earth, is clear from Fig. 47. When the earth is at A and +Mars at B, it will appear among the stars at C. When the earth is +at D, Mars having moved more slowly to E, will have retrograded +to F. It remains there while the earth passes on, in a line nearly +straight, from Mars to G; then, as the earth begins to curve around +the sun, Mars will appear to retraverse the distance from F to +C, and beyond. The farther the superior planet is from the earth +the less will be the retrograde movement. + +[Illustration: Fig. 47.--Illustrating Movements of a Superior Planet.] + +The reader should draw the orbits in proportion, and, remembering +the relative speed of each planet, note the movement of each in +different parts of their orbits. + +To account for these most simple movements, the earlier astronomers +invented the most complex and impossible machinery. They thought the +earth the centre, and that the sun, moon, and stars were carried +about it, as stoves around a person to warm him. They thought these +strange movements of the planets were accomplished by mounting them +on subsidiary eccentric wheels in the revolving crystal sphere. +All that was [Page 115] needed to give them a right conception was a +sinking of their world and themselves to an appropriate proportion, +and an enlargement of their vision, to take in from an exalted +stand-point a view of the simplicity of the perfect plan. + +EXPERIMENTS. + +Fix a rod, or tube, or telescope pointing at a star in the cast +or west, and the earth's revolution will be apparent in a moment, +turning the tube away from the star. Point it at stars about the +north pole, and those on one side will be found going in an opposite +direction from those on the other, and very much slower than those +about the equator. Anyone can try the pendulum experiment who has +access to some lofty place from which to suspend the ball. It was +tried in Bunker Hill Monument a few years ago, and is to be tried +in Paris, in the summer of 1879, with a seven-hundred-pound pendulum +and a suspending wire seventy yards long. The advance and retrograde +movements of planets can be illustrated by two persons walking +around a centre and noticing the place where the person appears +projected on the wall beyond. + + * * * * * + + PROCESSION OF STARS AND SOULS. + + "I stood upon the open casement, + And looked upon the night, + And saw the westward-going stars + Pass slowly out of sight. + + "Slowly the bright procession + Went down the gleaming arch, + And my soul discerned the music + Of the long triumphal march; + + "Till the great celestial army, + Stretching far beyond the poles, + Became the eternal symbol + Of the mighty march of souls. + +[Page 116] + "Onward, forever onward, + Red Mars led on his clan; + And the moon, like a mailčd maiden, + Was riding in the van. + + "And some were bright in beauty, + And some were faint and small, + But these might be, in their great heights, + The noblest of them all. + + "Downward, forever downward, + Behind earth's dusky shore, + They passed into the unknown night-- + They passed, and were no more. + + "No more! Oh, say not so! + And downward is not just; + For the sight is weak and the sense is dim + That looks through heated dust. + + "The stars and the mailčd moon, + Though they seem to fall and die, + Still sweep in their embattled lines + An endless reach of sky. + + "And though the hills of Death + May hide the bright array, + The marshalled brotherhood of souls + Still keeps its onward way. + + "Upward, forever upward, + I see their march sublime, + And hear the glorious music + Of the conquerors of Time. + + "And long let me remember + That the palest fainting one + May to diviner vision be + A bright and blazing sun." + + THOMAS BUCHANAN READ. + + + + +[Page 117] +VII. + +SHOOTING-STARS, METEORS, AND COMETS. + +"The Lord cast down great stones from heaven upon them unto Azekah, +and they died."--_Joshua_ x. II. + +[Page 118] +[Illustration: A SWARM OF METEORS MEETING THE EARTH. + +Their orbits are all parallel. Those coming in direct line to the +eye appear as stars, having no motion. Those on one side of this +line are seen in foreshortened perspective. Those furthest from +the centre, other things being equal, appear longest. The centre, +called the radiant point, of these November meteors is situated +in Leo; that of the August meteors in Perseus. Over fifty such +radiant points have been discovered. Over 30,000 meteors have been +visible in an hour.] + + + + +[Page 119] +VII. + +_SHOOTING-STARS, METEORS, AND COMETS._ + +Before particularly considering the larger aggregations of matter +called planets or worlds as individuals, it is best to investigate +a part of the solar system consisting of smaller collections of +matter scattered everywhere through space. They are of various +densities, from a cloudlet of rarest gas to solid rock; of various +sizes, from a grain's weight to little worlds; of various relations +to each other, from independent individuality to related streams +millions of miles long. When they become visible they are called +shooting-stars, which are evanescent star-points darting through +the upper air, leaving for an instant a brilliant train; meteors, +sudden lights, having a discernible diameter, passing over a large +extent of country, often exploding with violence (Fig. 48), and +throwing down upon the earth aerolites; and comets, vast extents +of ghostly light, that come we know not whence and go we know not +whither. All these forms of matter are governed by the same laws +as the worlds, and are an integral part of the solar system--a +part of the unity of the universe. + +[Illustration: Fig. 48.--Explosion of a Bolide.] + +Everyone has seen the so-called shooting-stars. They break out +with a sudden brilliancy, shoot a few degrees with quiet speed, +and are gone before we can say, "See there!" The cause of their +appearance, the [Page 120] conversion of force into heat by their +contact with our atmosphere, has been already explained. Other facts +remain to be studied. They are found to appear about seventy-three +miles above the earth, and to disappear about twenty miles nearer +the surface. Their average velocity, thirty-five, sometimes rises to +one hundred miles a second. They exhibit different colors, according +to their different chemical substances, which are consumed. The +number of them to be seen on different nights is exceedingly +variable; sometimes not more [Page 121] than five or six an hour, +and sometimes so many that a man cannot count those appearing in a +small section of sky. This variability is found to be periodic. +There are everywhere in space little meteoric masses of matter, from +the weight of a grain to a ton, and from the density of gas to rock. +The earth meets 7,500,000 little bodies every day--there is +collision--the little meteoroid gives out its lightning sign of +extinction, and, consumed in fervent heat, drops to the earth as gas +or dust. If we add the number light enough to be seen by a +telescope, they cannot be less than 400,000,000 a day. Everywhere we +go, in a space as large as that occupied by the earth and its +atmosphere, there must be at least 13,000 bodies--one in 20,000,000 +cubic miles--large enough to make a light visible to the naked eye, +and forty times that number capable of revealing themselves to +telescopic vision. Professor Peirce is about to publish, as the +startling result of his investigations, "that the heat which the +earth receives directly from meteors is the same in amount which it +receives from the sun by radiation, and that the sun receives +five-sixths of its heat from the meteors that fall upon it." + +[Illustration: Fig. 49.--Bolides.] + +[Page 121] +In 1783 Dr. Schmidt was fortunate enough to have a telescopic view +of a system of bodies which had turned into meteors. These were two +larger bodies followed by several smaller ones, going in parallel +lines till they were extinguished. They probably had been revolving +about each other as worlds and satellites before entering our +atmosphere. It is more than probable that the earth has many such +bodies, too small to be visible, revolving around it as moons. + +[Illustration: Fig. 50.--Santa Rosa Aerolite.] + +_Aerolites._ + +Sometimes the bodies are large enough to bear the heat, and the +unconsumed centre comes to the earth. [Page 123] Their velocity has +been lessened by the resisting air, and the excessive heat +diminished. Still, if found soon after their descent, they are too +hot to be handled. These are called aerolites or air-stones. There +was a fall in Iowa, in February, 1875, from which fragments +amounting to five hundred pounds weight were secured. On the evening +of December 21st, 1876, a meteor of unusual size and brilliancy +passed over the states of Kansas, Missouri, Illinois, Indiana, and +Ohio. It was first seen in the western part of Kansas, at an +altitude of about sixty miles. In crossing the State of Missouri it +began to explode, and this breaking up continued while passing +Illinois, Indiana, and Ohio, till it consisted of a large flock of +brilliant balls chasing each other across the sky, the number being +variously estimated at from twenty to one hundred. It was +accompanied by terrific explosions, and was seen along a path of not +less than a thousand miles. When first seen in Kansas, it is said to +have appeared as large as the full moon, and with a train from +twenty-five to one hundred feet long. Another, very similar in +appearance and behavior, passed over a part of the same course in +February, 1879. At Laigle, France, on April 26th, 1803, about one +o'clock in the day, from two to three thousand fell. The largest did +not exceed seventeen pounds weight. One fell in Weston, Connecticut, +in 1807, weighing two hundred pounds. A very destructive shower is +mentioned in the book of Joshua, chap. x. ver. 11. + +These bodies are not evenly distributed through space. In some +places they are gathered into systems which circle round the sun +in orbits as certain as those of the [Page 124] planets. The chain +of asteroids is an illustration of meteoric bodies on a large scale. +They are hundreds in number--meteors are millions. They have their +region of travel, and the sun holds them and the giant Jupiter by +the same power. The Power that cares for a world cares for a +sparrow. If their orbit so lies that a planet passes through it, and +the planet and the meteors are at the point of intersection at the +same time, there must be collisions, and the lightning signs of +extinction proportioned to the number of little bodies in a given +space. + +It is demonstrated that the earth encounters more than one hundred +such systems of meteoric bodies in a single year. It passes through +one on the 10th of August, another on the 11th of November. In +a certain part of the first there is an agglomeration of bodies +sufficient to become visible as it approaches the sun, and this is +known as the comet of 1862; in the second is a similar agglomeration, +known as Temple's comet. It is repeating the same thing to say that +meteoroids follow in the train of the comets. The probable orbit +of the November meteors and the comet of 1866 is an exceedingly +elongated ellipse, embracing the orbit of the earth at one end and +a portion of the orbit of Uranus at the other (Fig. 51). That of +the August meteors and the comet of 1862 embraces the orbit of +the earth at one end, and thirty per cent. of the other end is +beyond the orbit of Neptune. + +[Illustration: Fig. 51.--Orbit of the November Meteors and the Comet +or 1866.] + +In January, 1846, Biela's comet was observed to be divided. At +its next return, in 1852, the parts were 1,500,000 miles apart. +They could not be found on their periodic returns in 1859, 1865, +and 1872; but it [Page 125] should have crossed the earth's orbit +early in September, 1872. The earth itself would arrive at the point +of crossing two or three months later. If the law of revolution +held, we might still expect to find some of the trailing meteoroids +of the comet not gone by on our arrival. It was shown that the point +of the earth that would strike them would be toward a certain place +in the constellation of Andromeda, if the remains of the diluted +comet were still there. The prediction was verified in every +respect. At the appointed time, place, [Page 126] and direction, the +streaming lights were in our sky. That these little bodies belonged +to the original comet none can doubt. By the perturbations of +planetary attraction, or by different original velocities, a comet +may be lengthened into an invisible stream, or an invisible stream +agglomerated till it is visible as a comet. + +_Comets._ + +Comets will be most easily understood by the foregoing considerations. +They are often treated as if they were no part of the solar system; +but they are under the control of the same laws, and owe their +existence, motion, and continuance to the same causes as Jupiter and +the rest of the planets. They are really planets of wider wandering, +greater ellipticity, and less density. They have periodic times +less than the earth, and fifty times as great as Neptune. They +are little clouds of gas or meteoric matter, or both, darting into +the solar system from every side, at every angle with the plane +of the ecliptic, becoming luminous with reflected light, passing +the sun, and returning again to outer darkness. Sometimes they +have no tail, having a nucleus surrounded by nebulosity like a +dim sun with zodiacal light; sometimes one tail, sometimes half a +dozen. These follow the comet to perihelion, and precede it afterward +(Fig. 52). The orbits of some comets are enormously elongated; one +end may lie inside the earth's orbit, and the other end be as far +beyond Neptune as that is from the sun. Of course only a small +part of such a curve can be studied by us: the comet is visible +only when near the sun. The same curve around the sun may be an +orbit that will bring it back again, [Page 127] or one that will +carry it off into infinite space, never to return. One rate of speed +on the curve indicates an elliptical orbit that returns; a greater +rate of speed indicates that it will take a parabolic orbit, which +never returns. The exact rate of speed is exceedingly difficult to +determine; hence it cannot be confidently asserted that any comet +ever visible will not return. They may all belong to the solar +system; but some will certainly be gone thousands of years before +their fiery forms will greet the watchful eyes of dwellers on the +earth. A comet that has an elliptic orbit may have it changed to +[Page 128] parabolic by the accelerations of its speed, by +attracting planets; or a parabolic comet may become elliptic, and so +permanently attracted to the system by the retardations of +attracting bodies. A comet of long period may be changed to one of +short period by such attraction, or _vice versa_. + +[Illustration: Fig. 52.--Aspects of Remarkable Comets.] + +The number of comets, like that of meteor streams, is exceedingly +large. Five hundred have been visible to the naked eye since the +Christian era. Two hundred have been seen by telescopes invented +since their invention. Some authorities estimate the number belonging +to our solar system by millions; Professor Peirce says more than +five thousand millions. + +_Famous Comets._ + +The comet of 1680 is perhaps the one that appeared in A.D. 44, soon +after the death of Julius Cęsar, also in the reign of Justinian, +A.D. 531, and in 1106. This is not determined by any recognizable +resemblance. It had a tail 70° long; it was not all arisen when +its head reached the meridian. It is possible, from the shape of +its orbit, that it has a periodic time of nine thousand years, or +that it may have a parabolic orbit, and never return. Observations +taken two hundred years ago have not the exactness necessary to +determine so delicate a point. + +On August 19th, 1682, Halley discovered a comet which he soon declared +to be one seen by Kepler in 1607. Looking back still farther, he +found that a comet was seen in 1531 having the same orbit. Still +farther, by the same exact period of seventy-five years, he found +that it was the same comet that had disturbed [Page 129] the +equanimity of Pope Calixtus in 1456. Calculations were undertaken as +to the result of all the accelerations and retardations by the +attractions of all the planets for the next seventy-five years. +There was not time to finish all the work; but a retardation of six +hundred and eighteen days was determined, with a possible error of +thirty days. The comet actually came to time within thirty-three +days, on March 12th, 1759. Again its return was calculated with more +laborious care. It came to time and passed the sun within three days +of the predicted time, on the 16th of November, 1835. It passed from +sight of the most powerful telescopes the following May, and has +never since been seen by human eye. But the eye of science sees it +as having passed its aphelion beyond the orbit of Neptune in 1873, +and is already hastening back to the warmth and light of the sun. It +will be looked for in 1911; and there is good hope of predicting, +long before it is seen, the time of its perihelion within a day. + +_Biela's lost Comet._--This was a comet with a periodic time of +six years and eight months. It was observed in January, 1846, to +have separated into two parts of unequal brightness. The lesser +part grew for a month until it equalled the other, then became +smaller and disappeared, while the other was visible a month longer. +At disappearance the parts were 200,000 miles asunder. On its next +return, in 1852, the parts were 1,500,000 miles apart; sometimes +one was brighter and sometimes the other; which was the fragment +and which was the main body could not be recognized. They vanished +in September, 1852, and have never been seen since. Three revolutions +have been made since that time, but no [Page 130] trace of it could +be discovered. Probably the same influence that separated it into +parts, separated the particles till too thin and tenuous to be seen. +There is ground for believing that the earth passed through a part +of it, as before stated under the head of meteors. + +_The Great Comet of_ 1843 passed nearer the sun than any known +body. It almost grazed the sun. If it ever returns, it will be in +A.D. 2373. + +_Donati's Comet of_ 1858.--This was one of the most magnificent +of modern times. During the first three months it showed no tail, +but from August to October it had developed one forty degrees in +length. Its period is about two thousand years. Every reader remembers +the comet of the summer of 1875. + +_Encke's Comet._--This comet has become famous for its supposed +confirmation of the theory that space was filled with a substance +infinitely tenuous, which resisted the passage of this gaseous +body in an appreciable degree, and in long ages would so retard +the motion of all the planets that gravitation would draw them +all one by one into the sun. We must not be misled by the term +retardation to suppose it means behind time, for a retarded body +is before time. If its velocity is diminished, the attraction of +the sun causes it to take a smaller orbit, and smaller orbits mean +increased speed--hence the supposed retardation would shorten its +periodic time. This comet was thought to be retarded two and a +half hours at each revolution. If it was, it would not prove the +existence of the resisting medium. Other causes, unknown to us, +might account for it. Subsequent and more exact calculations fail +to find any retardations in at least two revolutions between 1865 +and [Page 131] 1871. Indications point to a retardation of one and a +half hours both before and since. But such discrepancy of result +proves nothing concerning a resisting medium, but rather is an +argument against its existence. Besides, Faye's comet, in four +revolutions of seven years each, shows no sign of retardation. + +The truth may be this, that a kind of atmosphere exists around the +sun, perhaps revealed by the zodiacal light, that reaches beyond +where Encke's comet dips inside the orbit of Mercury, and thus +retards this body, but does not reach beyond the orbit of Mars, +where Faye's comet wheels and withdraws. + +_Of what do Comets consist?_ + +The unsolved problems pertaining to comets are very numerous and +exceedingly delicate. Whence come they? Why did they not contract to +centres of nebulę? Are there regions where attractions are balanced, +and matter is left to contract on itself, till the movements of +suns and planets adds or diminishes attractive force on one side, +and so allows them to be drawn slowly toward one planet, and its +sun, or another? There is ground for thinking that the comet of +1866 and its train of meteors, visible to us in November, was thus +drawn into our system by the planet Uranus. Indeed, Leverrier has +conjecturally fixed upon the date of A.D. 128 as the time when it +occurred; but another and closer observation of its next return, +in 1899, will be needed to give confirmation to the opinion. Our +sun's authority extends at least half-way to the nearest fixed star, +one hundred thousand times farther than the orbit of the earth. +Meteoric and cometary matter lying [Page 132] there, in a spherical +shell about the solar system, balanced between the attraction of +different suns, finally feels the power that determines its destiny +toward our sun. It would take 167,000,000 years to come thence to +our system. + +The conditions of matter with which we are acquainted do not cover +all the ground presented by these mysterious visitors. We know +a gas sixteen times as light as air, but hydrogen is vastly too +heavy and dense; for we see the faintest star through thousands of +miles of cometary matter; we know that water may become cloudy vapor, +but a little of it obscures the vision. Into what more ethereal, +and we might almost say spiritual, forms matter may be changed we +cannot tell. But if we conceive comets to be only gas, it would +expand indefinitely in the realms of space, where there is no force +of compression but its own. We might say that comets are composed +of small separate masses of matter, hundreds of miles apart; and, +looking through thousands of miles of them, we see light enough +reflected from them all to seem continuous. Doubtless that is sometimes +the case. But the spectroscope shows another state of things: it +reveals in some of these comets an incandescent gas--usually some +of the combinations of carbon. The conclusion, then, naturally is +that there are both gas and small masses of matter, each with an +orbit of its own nearly parallel to those of all the others, and +that they afford some attraction to hold the mass of intermingled and +confluent gas together. Our best judgment, then, is that the nucleus +is composed of separate bodies, or matter in a liquid condition, +capable of being vaporized by the heat of the sun, and driven off, +[Page 133] as steam from a locomotive, into a tail. Indications of +this are found in the fact that tails grow smaller at successive +returns, as the matter capable of such vaporization becomes +condensed. In some instances, as in that of the comet of 1843, the +head was diminished by the manufacture of a tail. On the other hand, +Professor Peirce showed that the nucleus of the comets of 1680, +1843, and 1858 must have had a tenacity equal to steel, to prevent +being pulled apart by the tidal forces caused by its terrible +perihelion sweep around the sun. + +It is likely that there are great varieties of condition in different +comets, and in the same comet at times. We see them but a few days +out of the possible millions of their periodic time; we see them +only close to the sun, under the spur of its tremendous attraction +and terrible heat. This gives us ample knowledge of the path of +their orbit and time of their revolution, but little ground for +judgment of their condition, when they slowly round the uttermost +cape of their far-voyaging, in the terrible cold and darkness, +to commence their homeward flight. The unsolved problems are not +all in the distant sun and more distant stars, but one of them +is carried by us, sometimes near, sometimes far off; but our +acquaintance with the possible forms and conditions of matter is +too limited to enable us to master the difficulties. + +_Will Comets strike the Earth?_ + +Very likely, since one or two have done so within a recent period. +What will be the effect? That depends on circumstances. There is +good reason to suppose we passed through the tail of a comet in +1861, and the only [Page 134] observable effect was a peculiar +phosphorescent mist. If the comet were composed of small meteoric +masses a brilliant shower would be the result. But if we fairly +encountered a nucleus of any considerable mass and solidity, the +result would be far more serious. The mass of Donati's comet has +been estimated by M. Faye to be 1/20000 of that of the earth. If +this amount of matter were dense as water, it would make a globe +five hundred miles in diameter; and if as dense as Professor Peirce +proved the nucleus of this comet to be, its impact with the earth +would develop heat enough to melt and vaporize the hardest rocks. +Happily there is little fear of this: as Professor Newcomb says, "So +small is the earth in comparison with celestial space, that if one +were to shut his eyes and fire at random in the air, the chance of +bringing down a bird would be better than that of a comet of any +kind striking the earth." Besides, we are not living under a +government of chance, but under that of an Almighty Father, who +upholdeth all things by the word of his power; and no world can come +to ruin till he sees that it is best. + + + + +[Page 135] +VIII. + +THE PLANETS AS INDIVIDUALS. + +"Through faith we understand that the worlds [plural] were framed +by the word of God, so that things which were seen were not made +of things which do appear."--_Heb._ xi. 3. + +[Page 136] +"O rich and various man! Thou palace of sight and sound, carrying +in thy senses the morning, and the night, and the unfathomable +galaxy; in thy brain the geometry of the city of God; in thy heart +the power of love, and the realms of right and wrong. An individual +man is a fruit which it costs all the foregoing ages to form and +ripen. He is strong, not to do but to live; not in his arms, but +in his heart; not as an agent, but as a fact."--EMERSON. + + + + +[Page 137] +VII. + +_THE PLANETS AS INDIVIDUALS._ + +How many bodies there may be revolving about the sun we have no +means to determine or arithmetic to express. When the new star +of the American Republic appeared, there were but six planets +discovered. Since then three regions of the solar system have been +explored with wonderful success. The outlying realms beyond Saturn +yielded the planet Uranus in 1781, and Neptune in 1846. The middle +region between Jupiter and Mars yielded the little planetoid Ceres +in 1801, Pallas in 1802, and one hundred and ninety others since. +The inner region between Mercury and the sun is of necessity full +of small meteoric bodies; the question is, are there any bodies +large enough to be seen? + +The same great genius of Leverrier that gave us Neptune from the +observed perturbations of Uranus, pointed out perturbations in +Mercury that necessitated either a planet or a group of planetoids +between Mercury and the sun. Theoretical astronomers, aided by the +fact that no planet had certainly been seen, and that all asserted +discoveries of one had been by inexperienced observers, inclined +to the belief in a group, or that the disturbance was caused by +the matter reflecting the zodiacal light. + +When the total eclipse of the sun occurred in 1878, [Page 138] +astronomers were determined that the question of the existence of an +intra-mercurial planet should be settled. Maps of all the stars in +the region of the sun were carefully studied, sections of the sky +about the sun were assigned to different observers, who should +attend to nothing but to look for a possible planet. It is now +conceded that Professor Watson, of Ann Arbor, actually saw the +sought-for body. + + +VULCAN. + +The god of fire; its sign [Symbol], his hammer. + +DISTANCE FROM THE SUN, 13,000,000 MILES. ORBITAL REVOLUTION, ABOUT +20 DAYS. + + +MERCURY. + +The swift messenger of the gods; sign [Symbol], his caduceus. + +DISTANCE FROM THE SUN, 35,750,000 MILES. DIAMETER, 2992 MILES. +ORBITAL REVOLUTION, 87.97 DAYS. ORBITAL VELOCITY, 1773 MILES PER +MINUTE. AXIAL REVOLUTION, 24H. 5M. + +Mercury shines with a white light nearly as bright as Sirius; is +always near the horizon. When nearly between us and the sun, as +at D (Fig. 46, p. 113), its illuminated side nearly opposite to +us, we, looking from E, see only a thin crescent of its light. +When it is at its greatest angular distance from the sun, as A or +C, we see it illuminated like the half-moon. When it is beyond the +sun, as at E, we see its whole illuminated face like the full-moon. + +The variation of its apparent size from the varying distance is +very striking. At its extreme distance from the earth it subtends +an angle of only five seconds; nearest to us, an angle of twelve +seconds. Its distance from the earth varies nearly as one to three, +and its apparent size in the inverse ratio. + +[Page 139] +When Mercury comes between the earth and the sun, near the line +where the planes of their orbits cut each other by reason of their +inclination, the dark body of Mercury will be seen on the bright +surface of the sun. This is called a transit. If it goes across +the centre of the sun it may consume eight hours. It goes 100,000 +miles an hour, and has 860,000 miles of disk to cross. The transit of +1818 occupied seven and a half hours. The transits for the remainder +of the century will occur: + + November 7th 1881 | November 10th 1894 + May 9th 1891 | November 4th 1901 + + +VENUS. + +Goddess of beauty; its sign [Symbol], a mirror. + +DISTANCE FROM THE SUN, 66,750,000 MILES. DIAMETER, 7660 MILES. +ORBITAL VELOCITY, 1296 MILES PER MINUTE. AXIAL REVOLUTION, 23H. +21M. ORBITAL REVOLUTION, 224.7 DAYS. + +This brilliant planet is often visible in the daytime. I was once +delighted by seeing Venus looking down, a little after mid-day +through the open space in the dome of the Pantheon at Rome. It +has never since seemed to me as if the home of all the gods was +deserted. Phoebus, Diana, Venus and the rest, thronged through +that open upper door at noon of night or day. Arago relates that +Bonaparte, upon repairing to Luxemburg when the Directory was about +to give him a _fźte_, was much surprised at seeing the multitude +paying more attention to the heavens above the palace than to him +or his brilliant staff. Upon inquiry, he learned that these curious +persons were observing with astonishment a star which they supposed +to be that of the conqueror of Italy. The emperor himself was not +indifferent when [Page 140] his piercing eye caught the clear lustre +of Venus smiling upon him at mid-day. + +This unusual brightness occurs when Venus is about five weeks before +or after her inferior conjunction, and also nearest overhead by +being north of the sun. This last circumstance occurs once in eight +years, and came on February 16th, 1878. + +Venus may be as near the earth as 22,000,000 miles, and as far +away as 160,000,000. This variation of its distances from the earth +is obviously much greater than that of Mercury, and its consequent +apparent size much more changeable. Its greatest and least apparent +sizes are as ten and sixty-five (Fig. 53). + +[Illustration: Fig. 53.--Phases of Venus, and Varions Apparent +Dimensions.] + +When Copernicus announced the true theory of the solar system, he +said that if the inferior planets could be clearly seen they would +show phases like the moon. When Galileo turned the little telescope +he had made on Venus, he confirmed the prophecy of Copernicus. +Desiring to take time for more extended observation, and still be +able to assert the priority of his discovery, he published the +following anagram, in which his discovery was contained: + +[Page 141] + "Hęc immatura a me jam frustra leguntur o. y." + (These unripe things are now vainly gathered by me.) + +He first saw Venus as gibbous; a few months revealed it as crescent, +and then he transposed his anagram into: + + "Cynthię figuras ęmulatur mater amorum." + (The mother of loves imitates the phases of Cynthia.) + +Many things that were once supposed to be known concerning Venus are +not confirmed by later and better observations. Venus is surrounded +by an atmosphere so dense with clouds that it is conceded that +her time of rotation and the inclination of her axis cannot be +determined. She revealed one of the grandest secrets of the universe +to the first seeker; showed her highest beauty to her first ardent +lover, and has veiled herself from the prying eyes of later comers. + +Florence has built a kind of shrine for the telescope of Galileo. +By it he discovered the phases of Venus, the spots on the sun, +the mountains of the moon, the satellites of Jupiter, and some +irregularities of shape in Saturn, caused by its rings. Galileo +subsequently became blind, but he had used his eyes to the best +purpose of any man in his generation. + + +THE EARTH. + +Its sign [Symbol]. + +DISTANCE FROM THE SUN, 92,500,000 MILES. DIAMETER, POLAR, 7899 +MILES; EQUATORIAL, 7925-1/2 MILES. AXIAL REVOLUTION, 23H. 56M. +4.09S.; ORBITAL, 365.86. ORBITAL VELOCITY PER MINUTE, 1152.8 MILES. + +Let us lift ourselves up a thousand miles from the earth. We see it +as a ball hung upon nothing in empty space. As the drop of falling +water gathers itself [Page 142] into a sphere by its own inherent +attraction, so the earth gathers itself into a ball. Noticing +closely, we see forms of continents outlined in bright relief, and +oceanic forms in darker surfaces. We see that its axis of revolution +is nearly perpendicular to the line of light from the sun. One-half +is always dark. The sunrise greets a new thousand miles every hour; +the glories of [Page 143] the sunset follow over an equal space, +180° behind. We are glad that the darkness never overtakes the +morning. + +[Illustration: Fig. 54.--Earth and Moon in Space.] + +_The Aurora Borealis._ + +While east and west are gorgeous with sunrise and sunset, the north +is often more glorious with its aurora borealis. We remember that +all worlds have weird and inexplicable appendages. They are not +limited to their solid surfaces or their circumambient air. The +sun has its fiery flames, corona, zodiacal light, and perhaps a +finer kind of atmosphere than we know. The earth is +[Page 144] +not without its inexplicable surroundings. It has not only its +gorgeous eastern sunrise, its glorious western sunset, high above +its surface in the clouds, but it also has its more glorious northern +dawn far above its clouds and air. The realm of this royal splendor +is as yet an unconquered world waiting for its Alexander. There are +certain observable facts, viz., it prevails mostly near the arctic +circle rather than the pole; it takes on various forms--cloud-like, +arched, straight; it streams like banners, waves like curtains in +the wind, is inconstant; is either the cause or result of electric +disturbance; it is often from four hundred to six hundred miles +above the earth, while our air cannot be over one hundred miles. +It almost seems like a revelation to human eyes of those vast, +changeable, panoramic pictures by which the inhabitants of heaven +are taught. + +[Illustration: Fig. 55.--The Aurora as Waving Curtains.] + +Investigation has discovered far more mysteries than it has explained. +It is possible that the same cause that produces sun-spots produces +aurora in all space, visible in all worlds. If so, we shall see +more abundant auroras at the next maximum of sun-spot, between +1880-84. + +_The Delicate Balance of Forces._ + +A soap-bubble in the wind could hardly be more flexible in form +and sensitive to influence than is the earth. On the morning of +May 9th, 1876, the earth's crust at Peru gave a few great throbs +upward, by the action of expansive gases within. The sea fled, +and returned in great waves as the land rose and fell. Then these +waves fled away over the great mobile surface, and in less than +five hours they had covered a space equal to half of Europe. The +waves ran out to the Sandwich Islands, six [Page 145] thousand +miles, at the rate of five hundred miles an hour, and arrived there +thirty feet high. They not only sped on in straight radial lines, +but, having run up the coast to California, were deflected away into +the former series of waves, making the most complex undulations. +Similar beats of the great heart of the earth have sent its pulses +as widely and rapidly on previous occasions. + +The figure of the earth, even on the ocean, is irregular, in consequence +of the greater preponderance of land--and hence greater density--in the +northern hemisphere. These irregularities are often very perplexing +in making exact geodetic measurements. The tendency of matter to +fly from the centre by reason of revolution causes the equatorial +diameter to be twenty-six, miles longer than the polar one. By this +force the Mississippi River is enabled to run up a hill nearly +three miles high at a very rapid rate. Its mouth is that distance +farther from the centre of the earth than its source, when but +for this rotation both points would be equally distant. + +If the water became more dense, or if the world were to revolve +faster, the oceans would rush to the equator, burying the tallest +mountains and leaving polar regions bare. If the water should become +lighter in an infinitesimal degree, or the world rotate more slowly, +the poles would be submerged and the equator become an arid waste. +No balance, turning to 1/1000 of a grain, is more delicate than +the poise of forces on the world. Laplace has given us proof that +the period of the earth's axial rotation has not changed 1/100 +of a second of time in two thousand years. + +[Page 146] +_Tides._ + +But there is an outside influence that is constantly acting upon +the earth, and to which it constantly responds. Two hundred and +forty thousand miles from the earth is the moon, having 1/81 the +mass of the world. Its attractive influence on the earth causes the +movable and nearer portions to hurry away from the more stable and +distant, and heap themselves up on that part of the earth nearest +the moon. Gravitation is inversely as the square of the distance; +hence the water on the surface of the earth is attracted more than +the body of the earth, some parts of which are eight thousand miles +farther off; hence the water rises on the side next the moon. But +the earth, as a whole, is nearer the moon than the water on the +opposite side, and being drawn more strongly, is taken away from +the water, leaving it heaped up also on the side opposite to the +moon. + +A subsidiary cause of tides is found in the revolution of the earth +and moon about their common centre of gravity. Revolution about +an axis through the centre of a sphere enlarges the equator by +centrifugal force. Revolution about an axis touching the surface +of a flexible globe converts it into an egg-shaped body, with the +longer axis perpendicular to the axis of revolution. In Fig. 56 the +point of revolution is seen at the centre of gravity at G; hence, +in the revolution of earth and moon as one, a strong centrifugal +force is caused at D, and a less one at C. This gives greater height +to the tides than the attraction of the moon alone could produce. + +[Page 147] +[Illustration: Fig. 56.] + +If the earth had no axial revolution, the attractive point where +the tide rises would be carried around the earth once in twenty-seven +days by the moon's revolution about the earth. But since the earth +revolves on its axis, it presents a new section to the moon's attraction +every hour. If the moon were stationary, that would bring two high +tides in exactly twenty-four hours; but as the moon goes forward, +we need nearly twenty-five hours for two tides. + +The attractive influence of the sun also gives us a tide four-tenths +as great as that of the moon. When these two influences of the sun +and moon combine, as they do, in conjunction--when both bodies +are on one side of the earth; or in opposition, sun and moon being +on opposite sides of the earth--we have spring or increased tides. +When the moon is in its first or third quarter, _i. e._, when a +line from the moon to the earth makes a right angle with one from +the sun to the earth, these influences antagonize one another, +and we have the neap or low tides. + +It is easy to see that if, when the moon was drawing its usual +tide, the sun drew four-tenths of the water in a tide at right +angles with it, the moon's tide must be by so much lower. Because +of the inertia of the water [Page 148] it does not yield instantly +to the moon's influence, and the crest of the tide is some hours +behind the advancing moon. + +The amount of tide in various places is affected by almost innumerable +influences, as distance of moon at its apogee or perigee; its position +north, south, or at the equator; distance of earth from sun at +perihelion and aphelion; the position of islands; the trend of +continents, etc. All eastern shores have far greater tides than +western. As the earth rolls to the east it leaves the tide-crest +under the moon to impinge on eastern shores, hence the tides of +from seventy-five to one hundred feet in the Bay of Fundy. Lakes and +most seas are too small to have perceptible tides. The spring-tides +in the Mediterranean Sea are only about three inches. + +This constant ebb and flow of the great sea is a grand provision for +its purification. Even the wind is sent to the sea to be cleansed. +The sea washes every shore, purifies every cove, bay, and river +twice every twenty-four hours. All putrescible matter liable to +breed a pestilence is carried far from shore and sunk under fathoms +of the never-stagnant sea. The distant moon lends its mighty power +to carry the burdens of commerce. She takes all the loads that +can be floated on her flowing tides, and cheerfully carries them +in opposite directions in successive journeys. + +It must be conceded that the profoundest study has not mastered +the whole philosophy of tides. There are certain facts which are +apparent, but for an explanation of their true theory such men as +Laplace, Newton, and Airy have labored in vain. There are plenty +of other worlds still to conquer. + + +[Page 150] +[Illustration: Fig. 57.--Lunar Day.] + +[Page 151] +THE MOON. + +New moon, [Symbol]; first quarter, [Symbol]; full moon, [Symbol]; +last quarter, [Symbol]. + +EXTREME DISTANCE FROM THE EARTH, 259,600 MILES; LEAST, 221,000 +MILES; MEAN, 240,000 MILES. DIAMETER, 2164.6 MILES [2153, LOCKYER]. +REVOLUTION ABOUT THE EARTH, 29-1/2 DAYS. AXIAL REVOLUTION, SAME +TIME. + +When the astronomer Herschel was observing the southern sky from +the Cape of Good Hope, the most clever hoax was perpetrated that +ever was palmed upon a credulous public. Some new and wonderful +instruments were carefully described as having been used by that +astronomer, whereby he was enabled to bring the moon so close that +he could see thereon trees, houses, animals, and men-like human +beings. He could even discern their movements, and gestures that +indicated a peaceful race. The extent of the hoax will be perceived +when it is stated that no telescope that we are now able to make +reveals the moon more clearly than it would appear to the naked +eye if it was one hundred or one hundred and fifty miles away. +The distance at which a man can be seen by the unaided eye varies +according to circumstances of position, background, light, and +eye, but it is much inside of five miles. + +Since, however, the moon is our nearest neighbor, a member of our +own family in fact, it is a most interesting object of study. + +A glance at its familiar face reveals its unequal illumination. +All ages and races have seen a man in the moon. All lovers have +sworn by its constancy, and only part of them have kept their oaths. +Every twenty-nine or thirty days we see a silver crescent in the +west, and are glad if it comes over the right shoulder--so [Page +152] much tribute does habit pay to superstition. The next night it +is thirteen degrees farther east from the sun. We note the stars it +occults, or passes by, and leaves behind as it broadens its disk, +till it rises full-orbed in the east when the sun sinks in the west. +It is easy to see that the moon goes around the earth from west to +east. Afterward it rises later and smaller each night, till at +length, lost from sight, it rises about the same time as the sun, +and soon becomes the welcome crescent new moon again. + +The same peculiarities are always evident in the visible face of +the moon; hence we know that it always presents the same side to +the earth. Obviously it must make just one axial to one orbital +revolution. Hold any body before you at arm's-length, revolve it +one-quarter around you until exactly overhead. If it has not revolved +on an axis between the hands, another quarter of the surface is +visible; but if in going up it is turned a quarter over, by the +hands holding it steady, the same side is visible. Three causes +enable us to see a little more than half the moon's surface: 1. The +speed with which it traverses the ellipse of its orbit is variable. +It sometimes gets ahead of us, sometimes behind, and we see farther +around the front or back part. 2. The axis is a little inclined to +the plane of its orbit, and its orbit a little inclined to ours; +hence we see a little over its north pole, and then again over +the south pole. 3. The earth being larger, its inhabitants see +a little more than half-way around a smaller body. These causes +combined enable us to see 576/1000 of the moon's surface. Our eyes +will never see the other side of the moon. If, now, being solid, +her axial revolution could [Page 153] be increased enough to make +one more revolution in two or three years, that difference between +her axial and orbital revolution would give the future inhabitants +of the earth a view of the entire circumference of the moon. Yet if +the moon were once in a fluid state, or had oceans on the surface, +the enormous tide caused by the earth would produce friction enough, +as they moved over the surface, to gradually retard the axial +revolution till the two tidal elevations remained fixed toward and +opposite the earth, and then the axial and orbital revolutions would +correspond, as at present. In fact, we can prove that the form of +the moon is protuberant toward the earth. Its centre of gravity is +thirty-three miles beyond its centre of magnitude, which is the same +in effect as if a mountain of that enormous height rose on the earth +side. Hence any fluid, as water or air, would flow round to the +other side. + +The moon's day, caused by the sun's light, is 29-1/2 times as long +as ours. The sun shines unintermittingly for fifteen days, raising a +temperature as fervid as boiling water. Then darkness and frightful +cold for the same time succeed, except on that half where the earth +acts as a moon. The earth presents the same phases--crescent, full, +and gibbous--to the moon as the moon does to us, and for the same +causes. Lord Rosse has been enabled, by his six-foot reflector, to +measure the difference of heat on the moon under the full blaze +of its noonday and midnight. He finds it to be no less than five +hundred degrees. People not enjoying extremes of temperature should +shun a lunar residence. The moon gives us only 1/6180000 as much +light as the sun. A sky full of moons would scarcely make daylight. + +[Page 154] +[Illustration: Fig. 58.--View of the Moon near the Third Quarter. +From a Photograph by Professor Henry Draper.] + +There are no indications of air or water on the moon. When it occults +a star it instantly shuts off the light and as instantly reveals +it again. An atmosphere would gradually diminish and reveal the +light, and by refraction [Page 155] cause the star to be hidden in +much less time than the solid body of the moon would need to pass +over it. If the moon ever had air and water, as it probably did, +they are now absorbed in the porous lava of its substance. + +_Telescopic Appearance._ + +[Illustration: Fig. 59.--Illumination of Craters and Peaks.] + +Probably no one ever saw the moon by means of a good telescope +without a feeling of admiration and awe. Except at full-moon, we +can see where the daylight struggles with the dark along the line +of the moon's sunrise or sunset. This line is called the terminator. +It is broken in the extreme, because the surface is as rough as +possible. In consequence of the small gravitation of the moon, utter +absence of the expansive power of ice shivering the cliffs, or the +levelling power of rains, precipices can stand in perpendicularity, +mountains shoot up like needles, and cavities three miles deep +remain unfilled. The light of the sun falling on the rough body +of the moon, shown in section (Fig. 59), illuminates the whole +cavity at _a_, part of the one at _b_, casts a long shadow from the +mountain at _c_, and touches the tip of the one at _d_, which appears +to a distant observer as a point of light beyond the terminator, +As the moon revolves the conical cavity, _a_ is illuminated on +the forward side only; the light creeps down the backward side +of cavity _b_ to the bottom; mountain _c_. comes directly under +the sun and casts no shadow, and mountain _d_ casts its long shadow +over the plain. Knowing the time of revolution, and observing the +change of [Page 156] illumination, we can easily measure the height +of mountain and depth of crater. An apple, with excavations and +added prominences, revolved on its axis toward the light of a +candle, admirably illustrates the crescent light that fills either +side of the cavities and the shadows of the mountains on the plain. +Notice in Fig. 58 the crescent forms to the right, showing cavities +in abundance. + +[Illustration: Fig. 60.--Lunar Crater "Copernicus," after Secchi.] + +The selenography of one side of the moon is much better known to +us than the geography of the earth. Our maps of the moon are far +more perfect than those of the earth; and the photographs of lunar +objects by Messrs. Draper and De la Rue are wonderfully perfect, +[Page 157] and the drawings of Padre Secchi equally so (Fig. 60). +The least change recognizable from the earth must be speedily +detected. There are frequently reports of discoveries of volcanoes +on the moon, but they prove to be illusions. The moon will probably +look the same to observers a thousand years hence as it does to-day. + +This little orb, that is only 1/81 of the mass of the earth, has +twenty-eight mountains that are higher than Mont Blanc, that "monarch +of mountains," in Europe. + +_Eclipses._ + +[Illustration: Fig. 61.--Eclipses; Shadows of Earth and Moon.] + +It is evident that if the plane of the moon's orbit were to correspond +with that of the earth, as they all lie in the plane of the page +(Fig. 61), the moon must pass between the centres of the earth +and sun, and exactly behind the earth at every revolution. Such +successive and total darkenings would greatly derange all affairs +dependent on light. It is easily avoided. Venus does [Page 158] not +cross the disk of the sun at every revolution, because of the +inclination of the plane of its orbit to that of the earth (see Fig. +41, p. 107). So the plane of the orbit of the moon is inclined to +the orbit of the earth 5° 8' 39"; hence the full-moon is often above +or below the earth's shadow, and the earth is below or above the +moon's shadow at new moon. It is as if the moon's orbit were pulled +up one-quarter of an inch from the page behind the earth, and +depressed as much below it between the earth and the sun. The point +where the orbit of the moon penetrates the plane of the ecliptic is +called a node. If a new moon occur when the line of intersection of +the planes of orbits points to the sun, the sun must be eclipsed; if +the full-moon occur, the moon must be eclipsed. In any other +position the sun or moon will only be partially hidden, or no +eclipse will occur. + +If the new moon be near the earth it will completely obscure the +sun. A dime covers it if held close to the eye. It may be so far +from the earth as to only partially hide the sun; and, if it cover +the centre, leave a ring of sunlight on every side. This is called +an annular eclipse. Two such eclipses will occur this year (1879). +If the full-moon passes near the earth, or is at perigee, it finds +the cone of shadow cast by the earth larger, and hence the eclipse +is greater; if it is far from the earth, or near apogee, the earth's +shadow is smaller, and the eclipse less, or is escaped altogether. + +There is a certain periodicity in eclipses. Whenever the sun, moon, +and earth are in a line, as in the total eclipse of July 29th, +1878, they will be in the same position after the earth has made +about eighteen revolutions, [Page 159] and the moon two hundred and +sixteen--that is, eighteen years after. This period, however, is +disregarded by astronomers, and each eclipse calculated by itself to +the accuracy of a second. + +How terrible is the fear of ignorance and superstition when the sun +or moon appear to be in the process of destruction! how delightful +are the joys of knowledge when its prophesies in regard to the +heavenly bodies are being fulfilled! + + +MARS. + +The god or war; Its sign [Symbol], spear and shield. + +MEAN DISTANCE FROM THE SUN, 141,000,000 MILES. DIAMETER, 4211 MILES. +REVOLUTION, AXIAL, 24H. 37M. 22.7S.; ORBITAL, 686.98 DAYS. VELOCITY +PER MINUTE, 899 MILES. SATELLITES, TWO. + +[Illustration: Fig. 62.--Apparent Size of Mars at Mean and Extreme +Distances.] + +At intervals, on an average of two years one month and nineteen +days, we find rising, as the sun goes down, the reddest star in +the heavens. Its brightness is exceedingly variable; sometimes +it scintillates, and sometimes it shines with a steady light. Its +marked peculiarities demand a close study. We find it to be Mars, +the fiery god of war. Its orbit is far from circular. At perihelion +it is 128,000,000 miles from the sun, and at aphelion 154,000,000; +hence its mean distance is about 141,000,000. So great a change +in its distance from the sun easily accounts for the change in +its brilliancy. Now, if Mars and the earth revolved in circular +orbits, the one 141,000,000 miles from the sun, and the other +92,000,000, they would approach at conjunction within 49,000,000 +miles of each other, and at opposition be 233,000,000 miles apart. +But Mars at perihelion may be only 128,000,000 miles from the sun, +and earth at [Page 160] aphelion may be 94,000,000 miles from the +sun. They are, then, but 34,000,000 miles apart. This favorable +opportunity occurs about once in seventy-nine years. At its last +occurrence, in 1877, Mars introduced to us his two satellites, that +had never before been seen by man. In consequence of this greatly +varying distance, the apparent size of Mars differs very much (Fig. +62). Take a favorable time when the planet is near, also as near +overhead as it ever comes, so as to have as little atmosphere as +possible to penetrate, and study the planet. The first thing that +strikes the observer is a dazzling spot of white near the pole which +happens to be toward him, or at both poles when the planet is so +situated that they can be seen. When the north pole is turned toward +the sun the size of the spot sensibly diminishes, and the spot at +the south pole enlarges, and _vice versa_. Clearly they are +ice-fields. Hence Mars has water, and air to carry it, and heat to +melt ice. It is winter at the south pole when Mars is farthest from +the sun; therefore the ice-fields are larger than at the north pole. +It is summer at the south pole when Mars is nearest the sun. Hence +its ice-fields grow smaller [Page 161] than those of the north pole +in its summer. This carrying of water from pole to pole, and melting +of ice over such large areas, might give rise to uncomfortable +currents in ocean and air; but very likely an inhabitant of earth +might be transported to the surface of Mars, and be no more +surprised at what he observed there than if he went to some point of +the earth to him unknown. Day and night would be nearly of the same +length; winter would linger longer in the lap of spring; summer +would be one hundred and eighty-one days long; but as the seas are +more intermingled with the land, and the divisions of land have less +of continental magnitude, it may be conjectured that Mars might be a +comfortable place of residence to beings like men. Perhaps the +greatest surprise to the earthly visitor would be to find himself +weighing only four-tenths as much as usual, able to leap twice as +high, and lift considerable bowlders. + +_Satellites of Mars._ + +The night of August 11th, 1877, is famous in modern astronomy. +Mars has been a special object of study in all ages; but on that +evening Professor Hall, of Washington, discovered a satellite of +Mars. On the 16th it was seen again, and its orbital motion followed. +On the following night it was hidden behind the body of the planet +when the observation began, but at the calculated time--at four +o'clock in the morning--it emerged, and established its character as +a true moon, and not a fixed star or asteroid. Blessings, however, +never come singly, for another object soon emerged which proved +to be an inner satellite. This is extraordinarily near [Page 162] +the planet--only four thousand miles from the surface--and its +revolution is exceedingly rapid. The shortest period hitherto known +is that of the inner satellite of Saturn, 22h. 37m. The inner +satellite of Mars makes its revolution in 7h. 39m.--a rapidity so +much surpassing the axial revolution of the planet itself, that it +rises in the west and sets in the east, showing all phases of our +moon in one night. The outer satellite is 12,579 miles from Mars, +and makes its revolution in 30h. 18m. Its diameter is six and a +quarter miles; that of the inner one is seven and a half miles. This +can be estimated only by the amount of light given. + + +ASTEROIDS. + +ALREADY DISCOVERED (1879), 192. DISTANCES FROM THE SUN, FROM 200,000,000 +TO 315,000,000 MILES. DIAMETERS, FROM 20 TO 400 MILES. MASS OF ALL, +LESS THAN ONE-QUARTER OF THE EARTH. + +The sense of infinite variety among the countless number of celestial +orbs has been growing rapidly upon us for half a century, and doubtless +will grow much more in half a century to come. Just as we paused +in the consideration of planets to consider meteors and comets, +at first thought so different, so must we now pause to consider a +ring of bodies, some of which are as small in comparison to Jupiter, +the next planet, as aerolites are compared to the earth. + +In 1800 an association of astronomers, suspecting that a planet +might be found in the great distance between Mars and Jupiter, +divided the zodiac into twenty-four parts, and assigned one part to +each astronomer for a thorough search; but, before their organization +could commence work, Piazzi, an Italian astronomer of Palermo, [Page +163] found in Taurus a star behaving like a planet. In six weeks it +was lost in the rays of the sun. It was rediscovered on its +emergence, and named Ceres. In March, 1802, a second planet was +discovered by Olbers in the same gap between Mars and Jupiter, and +named Pallas. Here was an embarrassment of richness. Olbers +suggested that an original planet had exploded, and that more pieces +could be found. More were found, but the theory is exploded into +more pieces than a planet could possibly be. Up to 1879 one hundred +and ninety-two have been discovered, with a prospect of more. +Between 1871-75 forty-five were discovered, showing that they are +sought for with great skill. In the discovery of these bodies, our +American astronomers, Professors Watson and Peters, are without +peers. + +Between Mars and Jupiter is a distance of some 339,000,000 miles. +Subtract 35,000,000 miles next to Mars and 50,000,000 miles next +to Jupiter, and there is left a zone 254,000,000 miles wide outside +of which the asteroids never wander. If any ever did, the attraction +of Mars or Jupiter may have prevented their return. + +Since the orbits of Mars and Jupiter show no sign of being affected +by these bodies for a century past, it is probable that their number +is limited, or at least that their combined mass does not approximate +the size of a planet. Professor Newcomb estimates that if all that +are now discovered were put into one planet, it would not be over +four hundred miles in diameter; and if a thousand more should exist, +of the average size of those discovered since 1850, their addition +would not increase the diameter to more than five hundred miles. + +[Page 164] +That all these bodies, which differ from each other in no respect +except in brilliancy, can be noted and fixed so as not to be mistaken +one for another, and instantly recognized though not seen for a +dozen years, is one of the highest exemplifications of the accuracy +of astronomical observation. + + +JUPITER. + +The king of the gods; sign [Symbol], the bird of Jove. + +DISTANCE FROM THE SUN, PERIHELION, 457,000,000 MILES; APHELION, +503,000,000 MILES. DIAMETER, EQUATORIAL, 87,500 MILES; POLAR, 82,500 +MILES. VOLUME, 1300 EARTHS. MASS, 213 EARTHS. AXIAL REVOLUTION, 9H. +55M 20S. ORBITAL REVOLUTION, 11 YEARS 317 DAYS. VELOCITY, 483.6 +MILES PER MINUTE. + +[Illustration: Fig. 63.--Jupiter as seen by the great Washington +Telescope. Drawn by Mr. Holden.] + +Jupiter rightly wears the name of the "giant planet." His orbit +is more nearly circular than most smaller planets. He could not +turn short corners with facility. We know little of his surface. +His spots and belts are [Page 165] changeable as clouds, which they +probably are. Some spots may be slightly self-luminous, but not the +part of the planet we see. It is covered with an enormous depth of +atmosphere. Since the markings in the belts move about one hundred +miles a day, the Jovian tempests are probably not violent. It is, +however, a singular and unaccountable fact, as remarked by Arago, +that its trade-winds move in an opposite direction from ours. +Jupiter receives only one twenty-seventh as much light and heat from +the sun as the earth receives. Its lighter density, being about that +of water, indicates that it still has internal heat of its own. +Indeed, it is likely that this planet has not yet cooled so as to +have any solid crust, and if its dense vapors could be deposited on +the surface, its appearance might be more suggestive of the sun than +of the earth. + +_Satellites of Jupiter._ + +In one respect Jupiter seems like a minor sun--he is royally attended +by a group of planets: we call them moons. This system is a favorite +object of study to everyone possessing a telescope. Indeed, I have +known a man who could see these moons with the naked eye, and give +their various positions without mistake. Galileo first revealed +them to ordinary men. We see their orbits so nearly on the edge +that the moons seem to be sliding back and forth across and behind +the disk, and to varying distances on either side. Fig. 64 is the +representation of their appearance at successive observations in +November, 1878. Their motion is so swift, and the means of comparison +by one another and the planet so excellent, that they can be seen +to change their places, [Page 166] be occulted, emerge from shadow, +and eclipse the planet, in an hour's watching. + +[Illustration: Fig. 64.--_a._ Various Positions of Jupiter's Moons; +_b._ Greatest Elongation of each Satellite.] + + ELEMENTS OF JUPITER'S SATELLITES. + +-------------------------------------------------------------+ + | | Mean Distance | | | + | | from Jupiter. | Sidereal Period. | Diameter.| + | |---------------+------------------+----------| + | | Miles. | Days Hrs. Min. | Miles. | + | I. Io | 260,000 | 1 18 28 | 2,352 | + | II. Europa | 414,000 | 3 13 43 | 2,099 | + | III. Ganymede | 661,000 | 7 3 59 | 3,436 | + | IV. Callisto | 1,162,000 | 16 18 5 | 2,929 | + +-------------------------------------------------------------+ + +It is seen by the above table that all these moons are larger than +ours, one larger than Mercury, and the asteroids are hardly large +enough to make respectable moons for them. They differ in color: +I. and II. have a bluish tinge; III. a yellow; and IV. is red. +The amount of light given by these satellites varies in the most +sudden and inexplicable manner. Perhaps it may be owing to the +different distributions of land and water on them. The mass of all +of them is .000171 of Jupiter. + +[Page 167] +If the Jovian system were the only one in existence, it would be +a surprising object of wonder and study. A monster planet, 85,000 +miles in diameter, hung on nothing, revolving its equatorial surface +forty-five miles a minute, holding four other worlds in steady +orbits, some of them at a speed of seven hundred miles a minute, +and the whole system carried through space at five hundred miles +a minute. Yet the discovery of all this display of power, skill, +and stability is only reading the easiest syllables of the vast +literature of wisdom and power. + + +SATURN. + +The god or time; sign [Symbol], his scythe. + +MEAN DISTANCE FROM THE SUN, 881,000,000 MILES. DIAMETER, POLAR, +66,500 MILES; EQUATORIAL, 73,300 MILES. AXIAL REVOLUTION, 10H. +14M. PERIODIC TIME, 29T YEARS. MOONS, EIGHT. + +The human mind has used Saturn and the two known planets beyond +for the last 200 years as a gymnasium. It has exercised itself +in comprehending their enormous distances in order to clear those +greater spaces, to where the stars are set; it has exercised its +ingenuity at interpreting appearances which signify something other +than they seem, in order that it may no longer be deluded by any +sunrises into a belief that the heavenly dome goes round the earth. +That a wandering point of light should develop into such amazing +grandeurs under the telescope, is as unexpected as that every tiny +seed should show peculiar markings and colors under the microscope. + +[Illustration: Fig. 65.--View of Saturn and his Rings.] + +There are certain things that are easy to determine, such as size, +density, periodic time, velocity, etc.; but other things are exceedingly +difficult to determine. It requires long sight to read when the +book is held [Page 168] 800,000,000 miles away. Only very few, if +more than two, opportunities have been found to determine the time +of Saturn's rotation. On the evening of December 7th, 1870, +Professor Hall observed a brilliant white spot suddenly show itself +on the body of this planet. It was as if an eruption of white hot +matter burst up from the interior. It spread eastward, and remained +bright till January, when it faded. No such opportunity for getting +a basis on which to found a calculation of the time of the rotation +of Saturn has occurred since Sir William Herschel's observations; +and, very singularly, the two times deduced wonderfully +coincide--that of Herschel being 10h. 16m., that of Mr. Hall being +10h. 14m. + +[Page 169] +The density of Saturn is less than that of water, and its velocity +of rotation so great that centrifugal force antagonizes gravitation +to such an extent that bodies weigh on it about the same as on the +earth. All the fine fancies of the habitability of this vaporous +world, all the calculations of the number of people that could +live on the square miles of the planet and its enormous rings, +are only fancy. Nothing could live there with more brains than a +fish, at most. It is a world in formative processes. We cannot hear +the voice of the Creator there, but we can see matter responsive +to the voice, and moulded by his word. + +_Rings of Saturn._ + +The eye and mind of man have worked out a problem of marvellous +difficulty in finding a true solution of the strange appearance +of the rings. Galileo has the immortal honor of first having seen +something peculiar about this planet. He wrote to the Duke of Tuscany, +"When I view Saturn it seems _tricorps_. The central body seems the +largest. The two others, situated, the one on the east, and the +other on the west, seem to touch it. They are like two supporters, +who help old Saturn on his way, and always remain at his side." +Looking a few years later, the rings having turned from view, he +said, "It is possible that some demon mocked me;" and he refused +to look any more. + +Huyghens, in March, 1655, solved the problem of the triform appearance +of Saturn. He saw them as handles on the two sides. In a year they +had disappeared, and the planet was as round as it seemed to Galileo +in 1612. He did not, however, despair; and in October, [Page 170] +1656, he was rewarded by seeing them appear again. He wrote of +Saturn, "It is girdled by a thin plain ring, nowhere touching, +inclined to the ecliptic." + +Since that time discoveries have succeeded one another rapidly. +"We have seen by degrees a ring evolved out of a triform planet, +and the great division of the ring and the irregularities on it +brought to light. Enceladus, and coy Mimas, faintest of twinklers, +are caught by Herschel's giant mirrors. And he, too, first of men, +realizes the wonderful tenuity of the ring, along which he saw +those satellites travelling like pearls strung on a silver thread. +Then Bond comes on the field, and furnishes evidence to show that +we must multiply the number of separate rings we know not how many +fold. And here we reach the golden age of Saturnian discovery, +when Bond, with the giant refractor of Cambridge, and Dawes, with +his 6-1/3-inch Munich glass, first beheld that wonderful dark +semi-transparent ring, which still remains one of the wonders of +our system. But the end is not yet: on the southern surface of +the ring, ere summer fades into autumn, Otto Struve in turn comes +upon the field, detects, as Dawes had previously done, a division +even in the dark ring, and measures it, while it is invisible to +Lassell's mirror--a proof, if one were needed, of the enormous +superiority possessed by refractors in such inquiries. Then we +approach 1861, when the ring plane again passes through the earth, +and Struve and Wray observe curious nebulous appearances."[*] + +[Footnote *: Lockyer.] + +Our opportunities for seeing Saturn vary greatly. As the earth at +one part of its orbit presents its south pole [Page 171] to the sun, +then its equator, then the north pole, so Saturn; and we, in the +direction of the sun, see the south side of the rings inclined at an +angle of 27°; next the edge of the rings, like a fine thread of +light; then the north side at a similar inclination. On February +7th, 1878, Saturn was between Aquarius and Pisces, with the edge of +the ring to the sun. In 1885, the planet being in Taurus, the south +side of the rings will be seen at the greatest advantage. From 1881 +till 1885 all circumstances will combine to give most favorable +studies of Saturn. Meanwhile study the picture of it. The outer ring +is narrow, dark, showing hints of another division, sometimes more +evident than at others, as if it were in a state of flux. The inner, +or second, ring is much brighter, especially on the outer edge, and +shading off to the dusky edge next to the planet. There is no sign +of division into a third dusky innermost ring, as was plainly seen +by Bond. This, too, may be in a state of flux. + +The markings of the planet are delicate, difficult of detection, +and are not like those stark zebra stripes that are so often +represented. + +The distance between the planet and the second ring seems to be +diminished one-half since 1657, and this ring has doubled its breadth +in the same time. Some of this difference may be owing to our greater +telescopic power, enabling us to see the ring closer to the planet; +but in all probability the ring is closing in upon the central +body, and will touch it by A.D. 2150. Thus the whole ring must +ultimately fall upon the planet, instead of making a satellite. + +We are anxious to learn the nature of such a ring. [Page 172] +Laplace mathematically demonstrated that it cannot be uniform and +solid, and survive. Professor Peirce showed it could not be fluid, +and continue. Then Professor Maxwell showed that it must be formed +of clouds of satellites too small to be seen individually, and too +near together for the spaces to be discerned, unless, perhaps, we +may except the inner dark ring, where they are not near enough to +make it positively luminous. Indeed, there is some evidence that the +meteoroids are far enough apart to make the ring partially +transparent. + +We look forward to the opportunities for observation in 1882 with +the brightest hope that these difficult questions will be solved. + +_Satellites of Saturn._ + +The first discovered satellite of Saturn seen by Huyghens was in +1655, and the last by the Bonds, father and son, of Cambridge, +in 1848. These are eight in number, and are named: + + Distant from Saturn's centre. + I. Mimas 119,725 miles. + II. Enceladus 153,630 " + III. Tethys 190,225 " + IV. Dione 243,670 " + V. Rhea 340,320 " + VI. Titan 788,915 " + VII. Hyperion 954,160 " + VIII. Japetus 2,292,790 " + +Titan can be seen by almost any telescope; I., II., and III., only +by the most powerful instrument. All except Japetus revolve nearly +in the plane of the ring. Like the moons of Jupiter, they present +remarkable and unaccountable variations of brilliancy. An inspection +[Page 173] of the table reveals either an expectation that another +moon will be discovered between V. and VI., and about three more +between VII. and VIII., or that these gaps may be filled with groups +of invisible asteroids, as the gap between Mars and Jupiter. This +will become more evident by drawing Saturn, the rings, and orbits of +the moons all as circles, on a scale of 10,000 miles to the inch. +Saturn will be in the centre, 70,000 miles in diameter; then a gap, +decreasing twenty-nine miles a year to the first ring, of, say, +10,000 miles; a dark ring 9000 miles wide; next the brightest ring +18,300 miles wide; then a gap of 1750 miles; then the outer ring +10,000 miles wide; then the orbits of the satellites in order. + +If the scenery of Jupiter is magnificent, that of Saturn must be +sublime. If one could exist there, he might wander from the illuminated +side of the rings, under their magnificent arches, to the darkened +side, see the swift whirling moons; one of them presenting ten times +the disk of the earth's moon, and so very near as to enable him +to watch the advancing line of light that marks the lunar morning +journeying round that orb. + + +URANUS. + +Sign [Symbol]; the initial of Herschel, and sign of the world. + +DISTANCE FROM THE SUN, 1,771,000,000 MILES. DIAMETER, 31,700 MILES. +AXIAL REVOLUTION UNKNOWN. ORBITAL, 84 YEARS. VELOCITY PER MINUTE, +252 MILES. MOONS, FOUR. + +Uranus was presented to the knowledge of man as an unexpected reward +for honest work. It was first mistaken by its discoverer for a comet, +a mere cloud of vapor; but it proved to be a world, and extended the +[Page 174] boundaries of our solar system, in the moment of its +discovery, as much as all investigation had done in all previous +ages. + +Sir William Herschel was engaged in mapping stars in 1781, when he +first observed its sea-green disk. He proposed to call it _Georgium +Sidus_, in honor of his king; but there were too many names of the +gods in the sky to allow a mortal name to be placed among them. It +was therefore called Uranus, since, being the most distant body of +our system, as was supposed, it might appropriately bear the name +of the oldest god. Finding anything in God's realms of infinite +riches ought not to lead men to regard that as final, but as a +promise of more to follow. + +This planet had been seen five times by Flamsteed before its character +was determined--once nearly a century before--and eight times by +Le Monnier. These names, which might easily have been associated +with a grand discovery, are associated with careless observation. +Eyes were made not only to be kept open, but to have minds behind +them to interpret their visions. Herschel thought he discovered six +moons belonging to Uranus, but subsequent investigation has limited +the number to four. Two of these are seen with great difficulty by +the most powerful telescopes. + +If the plane of our moon's orbit were tipped up to a greater +inclination, revolving it on the line of nodes as an axis until +it was turned 85°, the moon, still continuing on its orbit in that +plane, would go over the poles instead of about the equator, and +would go back to its old path when the plane was revolved 180°; +but its revolution would now be from east to west, or [Page 175] +retrograde. The plane of the moons of Uranus has been thus inclined +till it has passed 10° beyond the pole, and the moons' motions are +retrograde as regards other known celestial movements. How Uranus +itself revolves is not known. There are more worlds to conquer. + + +NEPTUNE. + +God of the sea; sign [Symbol], his trident. + +DISTANCE FROM THE SUN, 2,775,000,000 MILES. DIAMETER, 34,500 MILES. +VELOCITY PER MINUTE, 201.6 MILES. AXIAL REVOLUTION UNKNOWN. ORBITAL, +164.78 YEARS. ONE MOON. + +Men sought for Neptune as the heroes sought the golden fleece. +The place of Uranus had been mapped for nearly one hundred years +by these accidental observations. On applying the law of universal +gravitation, a slight discrepancy was found between its computed +place and its observed place. This discrepancy was exceedingly +slight. In 1830 it was only 20"; in 1840,190"; in 1884, 2'. Two +stars that were 2' apart would appear as one to the keenest unaided +eye, but such an error must not exist in astronomy. Years of work +were given to its correction. Mr. John C. Adams, of Cambridge, +England, finding that the attraction of a planet exterior to Uranus +would account for its irregularities, computed the place of such +a hypothetical body with singular exactness in October, 1841; but +neither he nor the royal astronomer Airy looked for it. Another +opportunity for immortality was heedlessly neglected. Meanwhile, +M. Leverrier, of Paris, was working at the same problem. In the +summer of 1846 Leverrier announced the place of the exterior planet. +The conclusion was in striking coincidence with that of Mr. [Page +176] Clark. Mr. Challis commenced to search for the planet near the +indicated place, and actually saw and mapped the star August 4th, +1846, but did not recognize its planetary character. Dr. Galle, of +Berlin, on the 23d of September, 1846, found an object with a +planetary disk not plotted on the map of stars. It was the +sought-for world. It would seem easy to find a world seventy-six +times as large as the earth, and easy to recognize it when seen. The +fact that it could be discovered only by such care conveys an +overwhelming idea of the distance where it moves. + +[Illustration: Fig. 66.--Perturbation of Uranus.] + +The effect of these perturbations by an exterior planet is understood +from Fig. 66. Uranus and Neptune were in conjunction, as shown, +in 1822. But in 1820 it had been found that Uranus was too far +from the sun, and too much accelerated. Since 1800, Neptune, in +his orbit from F to E, had been hastening Uranus in his orbit D +from C to B, and also drawing it farther from the sun. After 1822, +Neptune, in passing from E to D, had been retarding Uranus in his +orbit from B to A. + +We have seen it is easy to miss immortality. There is still another +instance. Lalande saw Neptune on May 8th and 10th, 1795, noted that +it had moved a little, and that the observations did not agree; +but, supposing the first was wrong, carelessly missed the glory +of once more doubling the bounds of the empire of the sun. + +[Page 177] +It is time to pause and review our knowledge of this system. The +first view reveals a moon and earth endowed with a force of inertia +going on in space in straight lines; but an invisible elastic cord of +attraction holds them together, just counterbalancing this tendency +to fly apart, and hence they circle round their centre of gravity. +The revolving earth turns every part of its surface to the moon in +each twenty-four hours. By an axial revolution in the same time +that the moon goes round the earth, the moon holds the same point +of its surface constantly toward the earth. If we were to add one, +two, four, eight moons at appropriate distances, the result would +be the same. There is, however, another attractive influence--that +of the sun. The sun attracts both earth and moon, but their nearer +affection for each other keeps them from going apart. They both, +revolving on their axes and around their centre of gravity, sweep +in a vastly wider curve around the sun. Add as many moons as has +Jupiter or Saturn, the result is the same--an orderly carrying +of worlds through space. + +There lies the unsupported sun in the centre, nearer to infinity +in all its capacities and intensities of force than our minds can +measure, filling the whole dome to where the stars are set with +light, heat, and power. It holds five small worlds--Vulcan, Mercury, +Venus, Earth, and Mars--within a space whose radius it would require +a locomotive half a thousand years to traverse. It next holds some +indeterminate number of asteroids, and the great Jupiter, equal in +volume to 13,000 earths. It holds Saturn, Uranus, and Neptune, and +all their variously related satellites and rings. The two thoughts +that overwhelm us are distance and power. The period of [Page 178] +man's whole history is not sufficient for an express train to +traverse half the distance to Neptune. Thought wearies and fails in +seeking to grasp such distances; it can scarcely comprehend one +million miles, and here are thousands of them. Even the wings of +imagination grow weary and droop. When we stand on that outermost of +planets, the very last sentinel of the outposts of the king, the +very sun grown dim and small in the distance, we have taken only one +step of the infinite distance to the stars. They have not changed +their relative position--they have not grown brighter by our +approach. Neptune carries us round a vast circle about the centre of +the dome of stars, but we seem no nearer its sides. In visiting +planets, we have been only visiting next-door neighbors in the +streets of a seaport town. We know that there are similar neighbors +about Sirius and Arcturus, but a vast sea rolls between. As we said, +we stand with the outermost sentinel; but into the great void beyond +the king of day sends his comets as scouts, and they fly thousands +of years without for one instant missing the steady grasp of the +power of the sun. It is nearer almightiness than we are able to +think. + +If we cannot solve the problems of the present existence of worlds, +how little can we expect to fathom the unsoundable depths of their +creation and development through ages measureless to man! Yet the +very difficulty provokes the most ambitious thought. We toil at +the problem because it has been hitherto unsolvable. Every error +we make, and discover to be such, helps toward the final solution. +Every earnest thinker who climbs the shining worlds as steps to +a higher thought is trying to solve the problem God has given us +to do. + + + + +[Page 179] +IX. + +THE NEBULAR HYPOTHESIS. + +"And the earth was without form, and void; and darkness was upon +the face of the deep."--_Genesis_ i. 2. + +[Page 180] + "A dark + Illimitable ocean, without bound, + Without dimension, where length, breadth, and height, + And time, and place are lost."--MILTON. + +"It is certain that matter is somehow directed, controlled, and +arranged; while no material forces or properties are known to be +capable of discharging such functions."--LIONEL BEALE. + +"The laws of nature do not account for their own origin."--JOHN +STUART MILL. + + + + +[Page 181] +IX. + +_THE NEBULAR HYPOTHESIS._ + +The method by which the solar system came into its present form +was sketched in vast outline by Moses. He gave us the fundamental +idea of what is called the nebular hypothesis. Swedenborg, that +prodigal dreamer of vagaries, in 1734 threw out some conjectures of +the way in which the outlines were to be filled up; Buffon followed +him closely in 1749; Kant sought to give it an ideal philosophical +completeness; as he said, "not as the result of observation and +computation," but as evolved out of his own consciousness; and +Laplace sought to settle it on a mathematical basis. + +It has been modified greatly by later writers, and must receive +still greater modifications before it can be accepted by the best +scientists of to-day. It has been called "the grandest generalization +of the human mind;" and if it shall finally be so modified as to pass +from a tentative hypothesis to an accepted philosophy, declaring +the modes of a divine worker rather than the necessities of blind +force, it will still be worthy of that high distinction. + +Let it be clearly noted that it never proposes to do more than to +trace a portion of the mode of working which brought the universe +from one stage to another. It only goes back to a definite point, +never to absolute beginning, nor to nothingness. It takes matter +from [Page 182] the hand of the unseen power behind, and merely +notes the progress of its development. It finds the clay in the +hands of an intelligent potter, and sees it whirl in the process of +formation into a vessel. It is not in any sense necessarily +atheistic, any more than it is to affirm that a tree grows by vital +processes in the sun and dew, instead of being arbitrarily and +instantly created. The conclusion reached depends on the spirit of +the observer. Newton could say, "This most beautiful system of the +sun, planets, and comets could only proceed from the counsel and +dominion of an intelligent and powerful being!" Still it is well to +recognize that some of its most ardent defenders have advocated it +as materialistic. And Laplace said of it to Napoleon, "I have no +need of the hypothesis of a god." + +The materialistic statement of the theory is this: that matter +is at first assumed to exist as an infinite cloud of fire-mist, +dowered with power latent therein to grow of itself into every +possibility of world, flower, animal, man, mind, and affection, +without any interference or help from without. But it requires +far more of the Divine Worker than any other theory. He must fill +matter with capabilities to take care of itself, and this would +tax the abilities of the Infinite One far more than a constant +supervision and occasional interference. Instead of making the +vase in perfect form, and coloring it with exquisite beauty by +an ever-present skill, he must endow the clay with power to make +itself in perfect form, adorn itself with delicate beauty, and +create other vases. + +The nebular hypothesis is briefly this: All the matter composing +all the bodies of the sun, planets, and satellites once existed +in an exceedingly diffused state; [Page 183] rarer than any gas with +which we are acquainted, filling a space larger than the orbit of +Neptune. Gravitation gradually contracted this matter into a +condensing globe of immense extent. Some parts would naturally be +denser than others, and in the course of contraction a rotary +motion, it is affirmed, would be engendered. Rotation would flatten +the globe somewhat in the line of its axis. Contracting still more, +the rarer gases, aided by centrifugal force, would be left behind as +a ring that would ultimately be separated, like Saturn's ring, from +the retreating body. There would naturally be some places in this +ring denser than others; these would gradually absorb all the ring +into a planet, and still revolve about the central mass, and still +rotate on its own axis, throwing off rings from itself. Thus the +planet Neptune would be left behind in the first sun-ring, to make +its one moon; the planet Uranus left in the next sun-ring, to make +its four moons from four successive planet-rings; Saturn, with its +eight moons and three rings not made into moons, is left in the +third sun-ring; and so on down to Vulcan. + +The outer planets would cool off first, become inhabitable, and, +as the sun contracted and they radiated their own heat, become +refrigerated and left behind by the retreating sun. Of course the +outer planets would move slowly; but as that portion of the sun +which gave them their motion drew in toward the centre, keeping +its absolute speed, and revolving in the lessening circles of a +contracting body, it would give the faster motion necessary to +be imparted to Earth, Mercury, and Vulcan. + +The four great classes of facts confirmatory of this hypothesis +are as follows: 1st. All the planets move [Page 184] in the same +direction, and nearly in the same plane, as if thrown off from one +equator; 2d. The motions of the satellites about their primaries are +mostly in the same direction as that of their primaries about the +sun; 3d. The rotation of most of these bodies on their axes, and +also of the sun, is in the same direction as the motion of the +planets about the sun; 4th. The orbits of the planets, excluding +asteroids, and their satellites, have but a comparatively small +eccentricity; 5th. Certain nebulę are observable in the heavens +which are not yet condensed into solids, but are still bright gas. + +The materialistic evolutionist takes up the idea of a universe of +material world-stuff without form, and void, but so endowed as to +develop itself into orderly worlds, and adds to it this exceeding +advance, that when soil, sun, and chemical laws found themselves +properly related, a force in matter, latent for a million eons in +the original cloud, comes forward, and dead matter becomes alive +in the lowest order of vegetable life; there takes place, as Herbert +Spencer says, "a change from an indefinite, incoherent homogeneity, +into a definite, coherent heterogeneity, through continuous +differentiation and integration." The dead becomes alive; matter +passes from unconsciousness to consciousness; passes up from plant +to animal, from animal to man; takes on power to think, reason, +love, and adore. The theistic evolutionist may think that the same +process is gone through, but that an ever-present and working God +superintends, guides, and occasionally bestows a new endowment +of power that successively gives life, consciousness, mental, +affectional, and spiritual capacity. + +Is this world-theory true? and if so, is either of the [Page 185] +evolution theories true also? If the first evolution theory is true, +the evolved man will hardly know which to adore most, the Being that +could so endow matter, or the matter capable of such endowment. + +There are some difficulties in the way of the acceptance of the +nebular hypothesis that compel many of the most thorough scientists +of the day to withhold their assent to its entirety. The latest, and +one of the most competent writers on the subject, Professor Newcomb, +who is a mathematical astronomer, and not an easy theorist, evolving +the system of the universe from the depth of his own consciousness, +says: "Should any one be sceptical as to the sufficiency of these +laws to account for the present state of things, science can furnish +no evidence strong enough to overthrow his doubts until the sun +shall be found to be growing smaller by actual measurement, or the +nebulę be actually seen to condense into stars and systems." In +one of the most elaborate defences of the theory, it is argued that +the hypothesis explains why only one of the four planets nearest +the sun can have a moon, and why there can be no planet inside of +Mercury. The discovery of the two satellites to Mars and of the +planet Vulcan makes it all the worse for these facts. + +Some of the objections to the theory should be known by every thinker. +Laplace must have the cloud "diffused in consequence of excessive +heat," etc. Helmholtz, in order to account for the heat of the +contracting sun, must have the cloud relatively cold. How he and +his followers diffused the cloud without heat is not stated. + +The next difficulty is that of rotation. The laws [Page 186] of +science compel a contraction into one non-rotating body--a central +sun, indeed, but no planets about it. Laplace cleverly evades the +difficulty by not taking from the hand of the Creator diffused gas, +but a sun with an atmosphere filling space to the orbit of Neptune, +and _already in revolution_. He says: "It is four millions to one +that all motions of the planets, rotations and revolutions, were at +once imparted by an original common cause, of which we know neither +the nature nor the epoch." Helmholtz says of rotation, "the +existence of which must be assumed." Professor Newcomb says that the +planets would not be arranged as now, each one twice as far from the +sun as the next interior one, and the outer ones made first, but +that all would be made into planets at once, and the small inner +ones quite likely to cool off more rapidly. + +It is a very serious difficulty that at least one satellite does +not revolve in the right direction. How Neptune or Uranus could +throw their moons backward from its equator is not easily accounted +for. It is at least one Parthian arrow at the system, not necessarily +fatal, but certainly dangerous. + +A greater difficulty is presented by the recently discovered satellites +of Mars. The inner one goes round the planet in one-third part of +the time of the latter's revolution. How Mars could impart three +times the speed to a body flying off its surface that it has itself, +has caused several defenders of the hypothesis to rush forward +with explanations, but none with anything more than mere imaginary +collisions with some comet. It is to be noticed that accounting for +three times the speed is not enough; for as Mars shrunk away from +the [Page 187] ring that formed that satellite, it ought itself to +attain more speed, as the sun revolves faster than its planets, and +the earth faster than its moon. In defending the hypothesis, Mitchel +said: "Suppose we had discovered that it required more time for +Saturn or Jupiter to rotate on their axes than for their nearest +moon to revolve round them in its orbit; this would have falsified +the theory." It is also asserted that the newly discovered planet +Vulcan makes an orbital in less time than the sun makes an axial +revolution. + +In regard to one Martial moon, Professor Kirkwood, on whom Proctor +conferred the highest title that could be conferred, "the modern +Kepler," says: "Unless some explanation can be given, the short period +of the inner satellite will be doubtless regarded as a conclusive +argument against the nebular hypothesis." If gravitation be sufficient +to account for the various motions of the heavenly bodies, we have +a perplexing problem in the star known as 1830 Groombridge, now +in the Hunting Dogs of Bootes. It is thought to have a speed of +two hundred miles per second--a velocity that all the known matter +in the universe could not give to the star by all its combined +attraction. Neither could all that attraction stop the motion of +the star, or bend it into an orbit. Its motion must be accounted +for on some hypothesis other than the nebular. + +The nebulę which we are able to observe are not altogether confirmatory +of the hypothesis under consideration. They have the most fantastic +shapes, as if they had no relation to rotating suns in the formative +stages. There are vast gaps in the middle, where they ought to be +densest. Mr. Plumer, in the _Natural Science Review_, [Page 188] +says, in regard to the results of the spectroscopic revelations: "We +are furnished with distinct proof that the gases so examined are not +only of nearly equal density, but that they exist in a low state of +_tension. This fact is fatal to the nebular theory._" + +In the autumn of 1876 a star blazed out in Cygnus, which promised +to throw a flood of light on the question of world-making. Its +spectrum was like some of the fixed stars. It probably blazed ont +by condensation from some previously invisible nebula. But its +brilliancy diminished swiftly, when it ought to have taken millions +of years to cool. If the theory was true, it ought to have behaved +very differently. It should have regularly condensed from gas to a +solid sun by slow process. But, worst of all, after being a star +awhile, it showed unmistakable proofs of turning into a cloud-mist--a +star into a nebula, instead of _vice versa_. A possible explanation +will be considered under variable stars. + +Such are a few of the many difficulties in the way of accepting +the nebular hypothesis, as at present explained, as being the true +mode of development of the solar system. Doubtless it has come +from a hot and diffused condition into its present state; but when +such men as Proctor, Newcomb, and Kirkwood see difficulties that +cannot be explained, contradictions that cannot be reconciled by +the principles of this theory, surely lesser men are obliged to +suspend judgment, and render the Scotch verdict of "not proven." +Whatever truth there may be in the theory will survive, and be +incorporated into the final solution of the problem; which solution +will be a much grander generalization of the human mind than the +nebular hypothesis. + +[Page 189] +Of some things we feel very sure: that matter was once without +form and void, and darkness rested on the face of the mighty deeps; +that, instead of chaos, we have now cosmos and beauty; and that +there is some process by which matter has been brought from one +state to the other. Whether, however, the nebular hypothesis lays +down the road travelled to this transfiguration, we are not sure. +Some of it seems like solid rock, and some like shifting quicksand. +Doubtless there is a road from that chaos to this fair cosmos. +The nebular hypothesis has surveyed, worked, and perfected many +long reaches of this road, but the rivers are not bridged, the +chasms not filled, nor the mountains tunnelled. + +When men attempt to roll the hypothesis of evolution along the +road of the nebular hypothesis of worlds, and even beyond to the +production of vegetable and animal life, mind and affection, the +gaps in the road become evident, and disastrous. + +A soul that has reached an adoration for the Supreme Father cares +not how he has made him. Doubtless the way God chose was the best. +It is as agreeable to have been thought of and provided for in the +beginning, to have had a myriad ages of care, and to have come +from the highest existent life at last, as to have been made at +once, by a single act, out of dust. The one who is made is not to +say to the Maker, "Why hast thou formed me in this or that manner?" +We only wish the question answered in what manner we were really +made. + +Evolution, without constant superintendence and occasional new +inspiration of power, finds some tremendous chasms in the road +it travels. These must be spanned by the power of a present God +or the airy imagination [Page 190] of man. Dr. McCosh has happily +enumerated some of these tremendous gaps over which mere force +cannot go. Given, then, matter with mechanical power only, what are +the gaps between it and spirituality? + +"1. Chemical action cannot be produced by mechanical power. + +"2. Life, even in the lowest forms, cannot be produced from unorganized +matter. + +"3. Protoplasm can be produced only by living matter. + +"4. Organized matter is made up of cells, and can be produced only +by cells. Whence the first cell? + +"5. A living being can be produced only from a seed or germ. Whence +the first vegetable seed? + +"6. An animal cannot be produced from a plant. Whence the first +animal? + +"7. Sensation cannot be produced in insentient matter. + +"8. The genesis of a new species of plant or animal has never come +under the cognizance of man, either in pre-human or post-human ages, +either in pre-scientific or scientific times. Darwin acknowledges +this, and says that, should a new species suddenly arise, we have +no means of knowing that it is such. + +"9. Consciousness--that is, a knowledge of self and its +operations--cannot be produced out of mere matter or sensation. + +"10. We have no knowledge of man being generated out of the lower +animals. + +"11. All human beings, even savages, are capable of forming certain +high ideas, such as those of God and duty. The brute creatures +cannot be made to entertain these by any training. + +[Page 191] +"With such tremendous gaps in the process, the theory which would +derive all things out of matter by development is seen to be a +very precarious one. + +The truth, according to the best judgment to be formed in the present +state of knowledge, would seem to be about this: The nebular hypothesis +is correct in all the main facts on which it is based; but that neither +the present forces of matter, nor any other forces conceivable to +the mind of man, with which it can possibly be endowed, can account +for all the facts already observed. There is a demand for a personal +volition, for an exercise of intelligence, for the following of a +divine plan that embraces a final perfection through various and +changeful processes. The five great classes of facts that sustain +the nebular hypothesis seem set before us to show the regular order +of working. The several facts that will not, so far as at present +known, accord with that plan, seem to be set before us to declare +the presence of a divine will and power working his good pleasure +according to the exigencies of time and place. + + + + +[Page 193] +X. + +THE STELLAR SYSTEM. + +"The heavens number out the glory of the strong God."--DAVID. + +[Page 194] +Richter says that "an angel once took a man and stripped him of +his flesh, and lifted him up into space to show him the glory of +the universe. When the flesh was taken away the man ceased to be +cowardly, and was ready to fly with the angel past galaxy after +galaxy, and infinity after infinity, and so man and angel passed +on, viewing the universe, until the sun was out of sight--until +our solar system appeared as a speck of light against the black +empyrean, and there was only darkness. And they looked onward, +and in the infinities of light before, a speck of light appeared, +and suddenly they were in the midst of rushing worlds. But they +passed beyond that system, and beyond system after system, and +infinity after infinity, until the human heart sank, and the man +cried out: 'End is there none of the universe of God?' The angel +strengthened the man by words of counsel and courage, and they flew +on again until worlds left behind them were out of sight, and specks +of light in advance were transformed, as they approached them, into +rushing systems; they moved over architraves of eternities, over +pillars of immensities, over architecture of galaxies, unspeakable in +dimensions and duration, and the human heart sank again and called +ont: 'End is there none of the universe of God?' And all the stars +echoed the question with amazement: 'End is there none of the universe +of God?' And this echo found no answer. They moved on again past +immensities of immensities, and eternities of eternities, until +in the dizziness of uncounted galaxies the human heart sank for +the last time, and called out: 'End is there none of the universe +of God?' And again all the stars repeated the question, and the +angel answered: 'End is there none of the universe of God. Lo, +also, there is no beginning.'" + + + + +[Page 195] +X. + +_THE OPEN PAGE OF THE HEAVENS._ + +The Greeks set their mythological deities in the skies, and read +the revolving pictures as a starry poem. Not that they were the +first to set the blazonry of the stars as monuments of their thought; +we read certain allusions to stars and asterisms as far back as +the time of Job. And the Pleiades, Arcturus, and Orion are some of +the names used by Him who "calleth all the stars by their names, +in the greatness of his power." Homer and Hesiod, 750 B.C., allude +to a few stars and groups. The Arabians very early speak of the +Great Bear; but the Greeks completely nationalized the heavens. +They colonized the earth widely, but the heavens completely; and +nightly over them marched the grand procession of their apotheosized +divinities. There Hercules perpetually wrought his mighty labors +for the good of man; there flashed and faded the changeful star +Algol, as an eye in the head of the snaky-haired Medusa; over them +flew Pegasus, the winged horse of the poet, careering among the +stars; there the ship Argo, which had explored all strange seas +of earth, nightly sailed in the infinite realms of heaven; there +Perseus perpetually killed the sea-monster by celestial aid, and +perpetually won the chained Andromeda for his bride. Very evident +was their recognition of divine help: equally evident was [Page 196] +their assertion of human ability and dominion. They gathered the +illimitable stars, and put uncountable suns into the shape of the +Great Bear--the most colossal form of animal ferocity and +strength--across whose broad forehead imagination grows weary in +flying; but they did not fail to put behind him a representative of +themselves, who forever drives him around a sky that never sets--a +perpetual type that man's ambition and expectation correspond to +that which has always been revealed as the divine. + +The heavens signify much higher power and wisdom to us; we retain the +old pictures and groupings for the convenience of finding individual +stars. It is enough for the astronomer that we speak of a star as +situated right ascension 13' 45", declination 88° 40'. But for +most people, if not all, it is better to call it Polaris. So we +might speak of a lake in latitude 42° 40', longitude 79° 22', but +it would be clearer to most persons to say Chatauqua. For exact +location of a star, right ascension and declination must be given; +but for general indication its name or place in a constellation +is sufficiently exact. The heaven is rather indeterminably laid +out in irregular tracts, and the mythological names are preserved. +The brightest stars are then indicated in order by the letters of +the Greek alphabet--Alpha (a), Beta (b), Gamma (g), etc. After +these are exhausted, the Roman alphabet is used in the same manner, +and then numbers are resorted to; so that the famous star 61 Cygni +is the 111th star in brightness in that one constellation. An +acquaintance with the names, peculiarities, and movements of the +stars visible at different seasons of the year is an unceasing +source of pleasure. It [Page 197] is not vision alone that is +gratified, for one fine enough may hear the morning stars sing +together, and understand the speech that day uttereth unto day, and +the knowledge that night showeth unto night. One never can be alone +if he is familiarly acquainted with the stars. He rises early in the +summer morning, that he may see his winter friends; in winter, that +he may gladden himself with a sight of the summer stars. He hails +their successive rising as he does the coming of his personal +friends from beyond the sea. On the wide ocean he is commercing with +the skies, his rapt soul sitting in his eyes. Under the clear skies +of the East he hears God's voice speaking to him, as to Abraham, and +saying, "Look now toward the heavens, and tell the number of the +stars, if thou be able to number them." + +A general acquaintance with the stars will be first attempted; +a more particular knowledge afterward. Fig. 67 (page 201) is a +map of the circumpolar region, which is in full view every clear +night. It revolves daily round Polaris, its central point. Toward +this star, the two end stars of the Great Dipper ever point, and +are in consequence called "the Pointers." The map may be held toward +the northern sky in such a position as the stars may happen to be. +The Great Bear, or Dipper, will be seen at nine o'clock in the +evening above the pole in April and May; west of the pole, the +Pointers downward, in July and August; close to the north horizon +in October and November; and east of the pole the Pointers highest, +in January and February. The names of such constantly visible stars +should be familiar. In order, from the end of the tail of the Great +Bear, we have Benetnasch ae, Mizar z, Little Alcor close to it, +[Page 198] Alioth, e Megrez, d at the junction, has been growing +dimmer for a century, Phad, g Dubhe and Merak. It is best to get +some facility at estimating distances in degrees. Dubhe and Merak, +"the Pointers," are five degrees apart. Eighteen degrees forward of +Dubhe is the Bear's nose; and three pairs of stars, fifteen degrees +apart, show the position of the Bear's three feet. Follow "the +Pointers" twenty-nine degrees from Dubhe, and we come to the +pole-star. This star is double, made of two suns, both appearing as +one to the naked eye. It is a test of an excellent three-inch +telescope to resolve it into two. Three stars beside it make the +curved-up handle of the Little Dipper of Ursa Minor. Between the two +Bears, thirteen degrees from Megrez, and eleven degrees from Mizar, +are two stars in the tail of the Dragon, which curves about to +appropriate all the stars not otherwise assigned. Follow a curve of +fifteen stars, doubling back to a quadrangle from five to three +degrees on a side, and thirty-five degrees from the pole, for his +head. His tongue runs out to a star four degrees in front. We shall +find, hereafter, that the foot of Hercules stands on this head. This +is the Dragon slain by Cadmus, and whose teeth produced such a crop +of sanguinary men. + +The star Thuban was once the pole-star. In the year B.C. 2300 it +was ten times nearer the pole than Polaris is now. In the year +A.D. 2100 the pole will be within 30' of Polaris; in A.D. 7500, +it will be at a of Cepheus; in A.D. 13,500, within 7° of Vega; in +A.D. 15,700, at the star in the tongue of Draco; in A.D. 23,000, +at Thuban; in A.D. 28,000, back to Polaris. This indicates no change +in the position of the dome [Page 199] of stars, but a change in the +direction of the axis of the earth pointing to these various places +as the cycles pass. As the earth goes round its orbit, the axis, +maintaining nearly the same direction, really points to every part +of a circle near the north star as large as the earth's orbit, that +is, 185,000,000 miles in diameter. But, as already shown, that +circle is too small to be discernible at our distance. The wide +circle of the pole through the ages is really made up of the +interlaced curves of the annual curves continued through 25,870 +years. The stem of the spinning top wavers, describes a circle, and +finally falls; the axis of the spinning earth wavers, describes a +circle of nearly 28,000 years, and never falls. + +The star g Draconis, also called Etanin, is famous in modern astronomy, +because observations on this star led to the discovery of the +_aberration of light_. If we held a glass tube perpendicularly out +of the window of a car at rest, when the rain was falling straight +down, we could see the drops pass directly through. Put the car +in motion, and the drops would seem to start toward us, and the +top of the tube must be bent forward, or the drops entering would +strike on the backside of the tube carried toward them. So our +telescopes are bent forward on the moving earth, to enable the +entered light to reach the eye-piece. Hence the star does not appear +just where it is. As the earth moves faster in some parts of its +orbit than others, this aberration is sometimes greater than at +others. It is fortunate that light moves with a uniform velocity, +or this difficult, problem would be still further complicated. +The displacement of a star from this course is about 20".43. + +[Page 200] +On the side of Polaris, opposite to Ursa Major, is King Cepheus, +made of a few dim stars in the form of the letter K. Near by is +his brilliant wife Cassiopeia, sitting on her throne of state. +They were the graceless parents who chained their daughter to a +rock for the sea-monster to devour; but Perseus, swift with the +winged sandals of Mercury, terrible with his avenging sword, and +invincible with the severed head of Medusa, whose horrid aspect of +snaky hair and scaly body turned to stone every beholder, rescues +the maiden from chains, and leads her away by the bands of love. +Nothing could be more poetical than the life of Perseus. When he +went to destroy the dreadful Gorgon, Medusa, Pluto lent him his +helmet, which would make him invisible at will; Minerva loaned +her buckler, impenetrable, and polished like a mirror; Mercury +gave him a dagger of diamonds, and his winged sandals, which would +carry him through the air. Coming to the loathsome thing, he would +not look upon her, lest he, too, be turned to stone; but, guided +by the reflection in the buckler, smote off her head, carried it +high over Libya, the dropping blood turning to serpents, which +have infested those deserts ever since. + +[Illustration: Fig. 67.--Circumpolar Constellations. Always visible. +In this position.--January 20th, at 10 o'clock; February 4th, at +9 o'clock; and February 19th, at 8 o'clock.] + +The human mind has always been ready to deify and throne in the +skies the heroes that labor for others. Both Perseus and Hercules +are divine by one parent, and human by the other. They go up and +down the earth, giving deliverance to captives, and breaking every +yoke. They also seek to purge away all evil; they slay dragons, +gorgons, devouring monsters, cleanse the foul places of earth, +and one of them so wrestles with death as to win a victim from his +grasp. Finally, by [Page 201] an ascension in light, they go up to +be in light forever. They are not ideally perfect. They right wrong +by slaying wrong-doers, rather than by being crucified themselves; +they are just murderers; but that only plucks the fruit from the +tree of evil. They never attempted to infuse a holy life. They +punished rather than regenerated. It must be confessed, also, that +they were not sinless. But they were the best saviors the race could +imagine, and are examples of that perpetual effort of the human mind +to incarnate a Divine Helper who shall labor and die for the good of +men. + +[Page 202] +[Illustration: Fig. 68.--Algol is on the Meridian, 51° South of +Pole.--At 10 o'clock, December 7th; 9 o'clock, December 22d; 8 +o'clock, January 5th.] + +_Equatorial Constellations._ + +If we turn our backs on Polaris on the 10th of November, at 10 +o'clock in the evening, and look directly overhead, we shall see +the beautiful constellation of Andromeda. Together with the square +of Pegasus, it makes another enormous dipper. The star a Alpheratz +is in her face, the three at the left cross her breast. b and the +two above mark the girdle of her loins, and g is in the foot. Perseus +is near enough for help; and Cetus, the sea-monster, is far enough +away to do no harm. Below, and east of Andromeda, is the Ram of +the golden fleece, recognizable by the three stars in an acute +triangle. The brightest is called Arietis, or Hamel. East of this +are the Pleiades, and the V-shaped Hyades in Taurus, or the Bull. +The Pleiades rise about 9 o'clock on the evening of the 10th of +September, and at 3 o'clock A.M. on June 10th. + +[Page 203] +[Illustration: Fig. 69.--Capella (45° from the Pole) and Rigel +(100°) are on the Meridian at 8 o'clock February 7th, 9 o'clock +January 22d, and at 10 o'clock January 7th.] + +Fig. 69 extends east and south of our last map. It is the most +gorgeous section of our heavens. (See the Notes to the Frontispiece.) +Note the triangle, 26° on a side, made by Betelguese, Sirius, and +Procyon. A line from Procyon to Pollux leads quite near to Polaris. +Orion is the mighty hunter. Under his feet is a hare, behind him +are two dogs, and before him is the rushing bull. The curve of +stars to the right of Bellatrix, g, represents his shield of the +Nemean lion's hide. The three stars of his belt make a measure +3° long; the upper one, Mintaker, is less than 30' south of the +equinoctial. The ecliptic passes between Aldebaran and the Pleiades. +Sirius rises about 9 o'clock P.M. on the 1st of December, and about +4 o'clock A.M. on the 16th of August. Procyon rises about half an +hour earlier. + +[Page 204] +[Illustration: Fig. 70--Regulus comes on the Meridian, 79° south +from the Pole, at 10 o'clock March 23d, 9 o'clock April 8th, and +at 8 o'clock April 23d.] + +Fig. 70 continues eastward. Note the sickle in the head and neck +of the Lion. The star b is Denebola, in his tail. Arcturus appears +by the word Bootes, at the edge of the map. These two stars make +a triangle with Spica, about 35° on a side. The geometric head of +Hydra is easily discernible east of Procyon: The star g in the +Virgin is double, with a period of 145 years. z is just above the +equinoctial. There is a fine nebula two-thirds of the way from d to +ae, and a little above the line connecting the two. Coma Berenices +is a beautiful cluster of faint stars. Spica rises at 9 o'clock on +the 10th of February, at 5 o'clock A.M. on the 6th of November. + +[Page 205] +[Illustration: Fig. 7l.--Arcturus comes to the Meridian, 70° from +the Pole, at 10 o'clock May 25th, 9 o'clock June 9th, and at 8 +o'clock June 25th.] + +Fig. 71 represents the sky to the eastward and northward of the +last. A line drawn from Polaris and Benetnasch comes east of Arcturus +to the little triangle called his sons. Bootes drives the Great +Bear round the pole. Arcturus and Denebola make a triangle with +a, also called Cor Coroli, in the Hunting Dogs. This triangle, and +the one having the same base, with Spica for its apex, is called +the "Diamond of the Virgin." Hercules appears head down--a in the +face, b, g, d; in his shoulders, p; and ae; in the loins, t in the +knee, the foot being bent to the stars at the right. The Serpent's +head, making an X, is just at the right of the g of Hercules, and +the partial circle of the Northern Crown above. The head of Draco +is seen at b on the left of the map. Arcturus rises at 9 o'clock +about the 20th of February, and at 5 A.M. on the 22d of October; +Regulus 3h. 35m. Earlier. + +[Page 206] +[Illustration: Fig. 72.--Altair comes to the Meridian, 82° from +the Pole, at 10 o'clock P.M. August 18th, at 9 o'clock September +2d, and at 8 o'clock September 18th.] + +Fig. 72 portrays the stars eastward and southward. Scorpio is one +of the most brilliant and easily traced constellations. Antares, a, +in the heart, is double. In Sagittarius is the Little Milk-dipper, +and west of it the bended bow. Vega is at the top of the map. Near +it observe z, a double, and e, a quadruple star. The point to which +the solar system is tending is marked by the sign of the earth +below p; Herculis. The Serpent, west of Hercules, and coiled round +nearly to Aquila, is very traceable. In the right-hand lower corner +is the Centaur. Below, and always out of our sight, is the famous +a Centauri. The diamond form of the Dolphin is sometimes called +"Job's Coffin." The ecliptic passes close [Page 207] to b of +Scorpio, which star is in the head. Antares, in Scorpio, rises at 9 +o'clock P.M. on May 9th, and at 5 o'clock A.M. on January 5th. + +[Illustration: Fig. 73.--Fomalhaut comes to the Meridian, only 17° +from the horizon, at 8 o'clock November 4th.] + +In Fig. 73 we recognize the familiar stars of Pegasus, which tell +us we have gone quite round the heavens. Note the beautiful cross +in the Swan. b in the bill is named Albireo, and is a beautiful +double to almost any glass. Its yellow and blue colors are very +distinct. The place of the famous double star 61 Cygni is seen. The +first magnitude star in the lower left-hand corner is Fomalhaut, in +the Southern Fish. a Pegasi is in the diagonal corner from Alpharetz, +in Andromeda. The star below Altair is b Aquilę, and is called +Alschain; the one above is g Aquilę, named Tarazed. This is not +a brilliant section of the sky. Altair rises at 9 o'clock on the +29th of May, and at 6 o'clock A.M. on the 11th of January. + +[Page 208] +[Illustration: Fig. 74.--Southern Circumpolar Constellations invisible +north of the Equator.] + +Fig. 74 gives the stars that are never seen by persons north of +the earth's equator. In the Ship is brilliant Canopus, and the +remarkable variable ae. Below it is the beautiful Southern Cross, +near the pole of the southern heavens. Just below are the two first +magnitude stars Bungala, a, and Achernar, b, of the Centaur. Such +a number of unusually brilliant stars give the southern sky an +unequalled splendor. In the midst of them, as if for contrast, +is the dark hole, called by the sailors the "Coal-sack," where +even the telescope reveals no sign of light. Here, also, are the +two Magellanic clouds, both easily discernible by the naked eye; +the larger two hundred times the apparent size of the moon, lying +between the pole and Canopus, and the other between Achernar and +the pole. The smaller cloud is only one-fourth the size of the +other. Both are mostly resolvable into groups of stars from the +fifth to the fifteenth magnitude. + +[Page 209] +For easy out-door finding of the stars above the horizon at any +time, see star-maps at end of the book. + +_Characteristics of the Stars._ + +Such a superficial examination of stars as we have made scarcely +touches the subject. It is as the study of the baptismal register, +where the names were anciently recorded, without any knowledge +of individuals. The heavens signify much more to us than to the +Greeks. We revolve under a dome that investigation has infinitely +enlarged from their estimate. Their little lights were turned by +clumsy machinery, held together by material connections. Our vast +worlds are connected by a force so fine that it seems to pass out +of the realm of the material into that of the spiritual. Animal +ferocity or a human Hercules could image their idea of power. Ours +finds no symbol, but rises to the Almighty. Their heavens were full +of fighting Orions, wild bulls, chained Andromedas, and devouring +monsters. Our heavens are significant of harmony and unity; all +worlds carried by one force, and all harmonized into perfect music. +All their voices blend their various significations into a personal +speaking, which says, "Hast thou not heard that the everlasting +God, the Lord, the creator of the ends of the earth, fainteth not, +neither is weary?" There is no searching of his understanding. +Lift up your eyes on high, and behold who hath created all these +things, that brought out their host by number, that calleth them +all by their names in the greatness of his power; for that he is +strong in power not one faileth. + +[Page 210] +_Number._ + +We find about five thousand stars visible to the naked eye in the +whole heavens, both north and south. Of these twenty are of the +first magnitude, sixty-five of the second, two hundred of the third, +four hundred of the fourth, eleven hundred of the fifth, and three +thousand two hundred of the sixth. We think we can easily number +the stars; but train a six-inch telescope on a little section of the +Twins, where six faint stars are visible, and over three thousand +luminous points appear. The seventh magnitude has 13,000 stars; +the eighth, 40,000; the ninth, 142,000. There are 18,000,000 stars +in the zone called the Milky Way. When our eyes are not sensitive +enough to be affected by the light of far-off stars the tastimetre +feels their heat, and tells us the word of their Maker is true--"they +are innumerable."[*] + +[Footnote *: _Telescopic Work._--Look at the Hyades and Pleiades +in Taurus. Notice the different colors of stars in them both. Find +the cluster Pręsepe in Fig. 70, just a trifle above a point midway +between Procyon and Regulus. It is equally distant from Procyon and +a point a little below Pollux. Sweep along the Milky Way almost +anywhere, and observe the distribution of stars; in some places +perfect crowds, in others more sparsely scattered. Find with the +naked eye the rich cluster in Perseus. Draw a line from Algol to +a of Perseus (Fig. 67); turn at right angles to the right, at a +distance of once and four-tenths the first line a brightness will +be seen. The telescope reveals a gorgeous cluster.] + +_Double and Multiple Stars._ + +If we look up during the summer months nearly overhead at the star +e Lyra, east of Vega (Fig. 72), we shall see with the naked eye +that the star appears a little [Page 211] elongated. Turn your +opera-glass upon it, and two stars appear. Turn a larger telescope +on this double star, and each of the components separate into two. +It is a double double star. We know that if two stars are near in +reality, and not simply apparently so by being in the same line of +sight, they must revolve around a common centre of gravity, or rush +to a common ruin. Eagerly we watch to see if they revolve. A few +years suffice to show them in actual revolution. Nay, the movement +of revolution has been decided before the companion star was +discovered. Sirius has long been known to have a proper motion, such +as it would have if another sun were revolving about it. Even the +direction of the unseen body could always be indicated. In February, +1862, Alvan Clark, artist, poet, and maker of telescopes (which +requires even greater genius than to be both poet and artist), +discovered the companion of Sirius just in its predicted place. As a +matter of fact, one of Mr. Clark's sons saw it first; but their fame +is one. The time of revolution of this pair is fifty years. But one +companion does not meet the conditions of the movements. Here must +also be one or more planets too small or dark to be seen. The double +star x in the Great Bear (see Fig. 70) makes a revolution in +fifty-eight years. + +Procyon moves in an orbit which requires the presence of a companion +star, but it has as yet eluded our search. Castor is a double star; +but a third star or planet, as yet undiscovered, is required to +account for its perturbations. Men who discovered Neptune by the +perturbations of Uranus are capable of judging the cause of the +perturbations of suns. We have spoken of [Page 212] the whole orbit +of the earth being invisible from the stars. The nearest star in our +northern hemisphere, 61 Cygni, is a telescopic double star; the +constituent parts of it are forty-five times as far from each other +as the earth is from the sun, yet it takes a large telescope to show +any distance between the stars.[*] + +[Footnote *: _Telescopic Work._--Only such work will be laid out +here as can be done by small telescopes of from two to four inch +object-glasses. The numbers in Fig. 75 correspond to those of the +table. + + -------------------------------------------------------------------- +| | | |Dist. of|Magni-| | +|No.| Name. | Fig. | Parts. |tudes.| Remarks. | +|---|------------|-------------|--------|------|---------------------| +| 1.| e Lyrę | 72 | 1' 56" | |Quadruple. | +| 2.| z Lyrę | 72 | 44 |5 & 6 |Topaz and green. | +| 3.| b Cygni | 73 | 34-1/2|3 & 6 |Yellow and blue. | +| 4.| 61 Cygni | 73 | 20 |5 & 6 |Nearest star but one.| +| 5.| Mizar | 67 | 14 |3 & 4 |Both white. | +| 6.| Polaris | 67 | 18-1/2|2 & 9 |Test object of eye | +| | | | | | and glass. | +| 7.| r Orionis |Frontispiece.| 7 |5 & 8 |Yellow and blue. | +| 8.| b Orionis | " | 9 |1 & 8 | Rigel. | +| 9.| d " | " | 10 |2 & 8 | Red and white. | +|10.| th " | " | | |Septuple. | +|11.| l " | " | 5 | |White and violet. | +|12.| s " | " A, B.| 11 |4 & 10|Octuple. | +|13.| Castor | 69 | 5-1/2|2 & 3 |White. | +|14.| Pollux | 69 | |Triple|Orange, gray, lilac. | +|15.| g Virginis | 70 | 5 |3 & 3 |Both yellow. | + -------------------------------------------------------------------- +] + +When g Virginis was observed in 1718 by Bradley, the component +parts were 7" asunder. He incidentally remarked in his note-book +that the line of their connection was parallel to the line of the +two stars Spica, or a and d Virginis. By 1840 they were not more +than 1" apart, and the line of their connection greatly changed. +The appearance of the star is given in Fig. 75 (15), commencing +at the left, for the years 1837 '38 '39 '40 '45 '50 '60 and '79. +also a conjectural [Page 213] orbit, placed obliquely, and the +position of the stars at the times mentioned, commencing at the top. +The time of its complete revolution is one hundred and fifty years. + +[Illustration: Fig. 75.--Aspects and Revolution of Double Stars.] + +The meaning of these double stars is that two or more suns revolve +about their centre of gravity, as the moon and earth about their +centre. If they have planets, as doubtless they have, the movement +is no more complicated than the planets we call satellites of Saturn +revolving about their central body, and also about the sun. Kindle +Saturn and Jupiter to a blaze, or let out their possible light, and +our system would appear a triple star in the distance. Doubtless, +in the far past, before these giant planets were cooled, it so +appeared. + +We find some stars double, others triple, quadruple, octuple, and +multiple. It is an extension of the same principles that govern +our system. Some of these suns are so far asunder that they can +swing their Neptunes between them, with less perturbation than +Uranus and Neptune have in ours. Light all our planets, and there +would be a multiple star with more or less suns seen, +[Page 214] +according to the power of the instrument. Perhaps the octuple star +s in Orion differs in no respect from our system, except in the +size and distance of its separate bodies, and less cooling, either +from being younger, or from the larger bodies cooling more slowly. +Suns are of all ages. Infinite variety fills the sky. It is as +preposterous to expect that every system or world should have analogous +circumstances to ours at the present time, as to insist that every +member of a family should be of the same age, and in the same state +of development. There are worlds that have not yet reached the +conditions of habitability by men, and worlds that have passed +these conditions long since. Let them go. There are enough left, +and an infinite number in the course of preparation. Some are fine +and lasting enough to be eternal mansions. + +_Colored Stars._ + +In the cloudy morning we get only red light, but the sun is white. +So Aldebaran and Betelguese may be girt by vapors, that only the +strong red rays can pass. Again, an iron moderately heated gives +out dull red light; becoming hotter, it emits white light. Sirius, +Regulus, Vega, and Spica may be white from greater intensity of +vibration. Procyon, Capella, and Polaris are yellow from less intensity +of vibration. Again, burn salt in a white flame, and it turns to +yellow; mix alcohol and boracic acid, ignite them, and a beautiful +green flame results; alcohol and nitrate of strontia give red flame; +alcohol and nitrate of barytes give yellow flame. So the composition +of a sun, or the special development of anyone substance thereof +at any time, may determine the color of a star. + +[Page 215] +The special glory of color in the stars is seen in the marked contrasts +presented in the double and multiple stars. The larger star is +usually white, still in the intensity of heat and vibration; the +others, smaller, are somewhat cooled off, and hence present colors +lower down the scale of vibration, as green, yellow, orange, and +even red. + +That stars should change color is most natural. Many causes would +produce this effect. The ancients said Sirius was red. It is now +white. The change that would most naturally follow mere age and +cooling would be from white, through various colors, to red. We are +charmed with the variegated flowers of our gardens of earth, but +he who makes the fields blush with flowers under the warm kisses of +the sun has planted his wider gardens of space with colored stars. +"The rainbow flowers of the footstool, and the starry flowers of +the throne," proclaim one being as the author of them all. + +_Clusters of Stars._ + +From double and multiple we naturally come to groups and clusters. +Allusion has been made to the Hyades, Pleiades, etc. Everyone has +noticed the Milky Way. It seems like two irregular streams of compacted +stars. It is not supposed that they are necessarily nearer together +than the stars in the sparse regions about the pole. But the 18,000,000 +suns belonging to our system are arranged within a space represented +by a flattened disk. If one hundred lights, three inches apart, +are arranged on a hoop ten feet in diameter, they would be in a +circle. Add a thousand or two more the same distance apart, filling +up the centre, and [Page 216] extending a few inches on each side of +the inner plane of the hoop: an eye in the centre, looking out +toward the edge, would see a milky way of lights; looking out toward +the sides or poles, would see comparatively few. It would seem as if +this oblate spheroidal arrangement was the result of a revolution of +all the suns composing the system. Jupiter and earth are flattened +at the poles for the same reason. + +[Illustration: Fig. 76.--Sprayed Cluster below ae in Hercules.] + +[Illustration: Fig. 77.--Globular Cluster.] + +In various parts of the heavens there are small globular well-defined +clusters, and clusters very irregular in form, marked with sprays +of stars. There is a cluster of this latter class in Hercules, +just under the S, in Fig. 72. "Probably no one ever saw it with a +good telescope without a shout of wonder." Here is a cluster of the +former class represented in Fig. 77. "The noble globular cluster, +o Centauri is beyond all comparison the richest and largest object +of the kind in the heavens. Its stars are literally innumerable; +and as their total light, when received by the naked eye, affects +it hardly more than a star of the fifth to fourth +[Page 217] +magnitude, the minuteness of each star may be imagined." + +There are two possibilities of thought concerning these clusters. +Either that they belong to our stellar system, and hence the stars +must be small and young, or they are another universe of millions +of suns, so far way that the inconceivable distances between the +stars are shrunken to a hand's-breadth, and their unbearable splendor +of innumerable suns can only make a gray haze at the distance at +which we behold them. The latter is the older and grander thought; +the former the newer and better substantiated. + +_Nebulę._ + +The gorgeous clusters we have been considering appear to the eye +or the small telescope as little cloudlets of hazy light. One after +another were resolved into stars; and the natural conclusion was, +that all would yield and reveal themselves to be clustered suns, +when we had telescopes of sufficient power. But the spectroscope, +seeing not merely form but substance also, shows that some of them +are not stars in any sense, but masses of glowing gas. Two of these +nebulę are visible to the naked eye: one in Andromeda (see Fig. +68), and one around the middle star of the sword of Orion, shown +in Fig.78. A three-inch telescope resolves th Orionis into the +famous trapezium, and a nine-inch instrument sees two stars more. +The shape of the nebula is changeable, and is hardly suggestive of +the moulding influence of gravitation. It is probably composed of +glowing nitrogen and hydrogen gases. Nebulę are of all conceivable +shapes--circular, annular, oval, lenticular, [Page 218] conical, +spiral, snake-like, looped, and nameless. Compare the sprays of the +Crab nebulę above z Tauri, seen in Fig. 79, and the ring nebula, +Fig. 80. This last possibly consists of stars, and is situated, as +shown in Fig. 81, midway between b and g Lyrę. + +[Illustration: Fig. 78.--The great Nebula about the multiple Star +th Orionis. (See Frontispiece.)] + +When Herschel was sweeping the heavens with his telescope, and +saw but few stars, he often said to his assistant, "Prepare to +write; the nebulę are coming." They are most abundant where the +stars are least so. A zone about the heavens 30° wide, with the +Milky Way in the centre, would include one-fourth of the celestial +sphere; but instead of one-fourth, we find nine-tenths +[Page 219] +of the stars in this zone, and but one-tenth of the nebulę. + +These immense masses of unorganized matter are noticed to change +their forms, vary their light greatly, but not quickly; they change +through the ages. "God works slowly." He takes a thousand years +to lift his hand off. + +[Illustration: Fig. 79.--Crab Nebula, near z Tauri. (See Frontispiece.)] + +There are many unsolved problems connected with these strange bodies. +Whether they belong to our system, or are beyond it, is not settled; +the weight of evidence leans to the first view. + +[Page 220] +_Variable Stars._ + +[Illustration: Fig. 80.--The Ring Nebula.] + +Our sun gives a variable amount of light, changing through a period +of eleven years. Probably every star, if examined by methods +sufficiently delicate and exact, would be found to be variable. +The variations of some [Page 221] stars are so marked as to +challenge investigation. b Lyrę (Fig. 81) has two maxima and minima +of light. In three days it rises from magnitude 4-1/2 to 3-1/2; in a +week falls to 4, and rises to 3-1/2; and in three days more drops to +4-1/2: it makes all these changes in thirteen days; but this period +is constantly increasing. The variations of one hundred and +forty-three stars have been well ascertained. + +[Illustration: Fig. 81.--Constellation Lyra, showing place of the +Ring Nebula.] + +Mira, or the Wonderful, in the Whale (Fig. 68), is easily found when +visible. Align from Capella to the Pleiades, and as much farther, +and four stars will be seen, situated thus: + + * + * * * + +The right-hand one is Mira. For half a month it shines as a star +of the second magnitude. Then for three months it fades away, and +lost to sight; going down even to the eleventh magnitude. But after +five months its resurrection morning mes; and in three months +more--eleven months in all--our Wonderful is in its full glory +in the heavens. It its period and brilliancy are also variable. +The star Megrez, d in the Great Bear, has been growing dim [Page +222] for a century. In 1836 Betelguese was exceedingly variable, and +continued so till 1840, when the changes became much less +conspicuous. Algol (Fig. 68) has been already referred to. This +slowly winking eye is of the second magnitude during 2d. 14h. Then +it dozes off toward sleep for 4h. 24m., when it is nearly invisible. +It wakes up during the same time; so that its period from maximum +brilliancy to the same state again is 2d. 20h. 48m. Its recognizable +changes are within five or six hours. As I write, March 25th, 1879, +Algol gives its minimum light at 9h. 36m. P.M. It passes fifteen +minima in 43d. 13m. There will therefore be another minimum May 7th, +at 9h. 49m. Its future periods are easy to estimate. Perhaps it has +some dark body revolving about it at frightful speed, in a period of +less than three days. The period of its variability is growing +shorter at an increasing rate. If its variability is caused by a +dark body revolving about it, the orbit of that body is contracting, +and the huge satellite will soon, as celestial periods are reckoned, +commence to graze the surface of the sun itself, rebound again and +again, and at length plunge itself into the central fire. Such an +event would evolve heat enough to make Algol flame up into a star of +the first magnitude, and perhaps out-blaze Sirius or Capella in our +winter sky. + +None of the causes for these changes we have been able to conjecture +seem very satisfactory. The stars may have opaque planets revolving +about them, shutting off their light; they may rotate, and have +unequally illuminated sides; they may revolve in very elliptical +orbits, so as to greatly alter their distance from us; they may +be so situated in regard to zones of meteorites as [Page 223] to +call down periodically vast showers; but none or all of these +suppositions apply to all cases, if they do to any. + +_Temporary, New, and Lost Stars._ + +Besides regular movements to right and left, up and down, to and +from us--changes in the intensity of illumination by changes of +distance--besides variations occurring at regular and ascertainable +intervals, there are stars called _temporary_, shining awhile and +then disappearing; _new_, coming to a definite brightness, and so +remaining; and _lost_, those whose first appearance was not observed, +but which have utterly disappeared. + +In November, 1572, a new star blazed out in Cassiopeia. Its place +is shown in Fig. 67, ch g being the stars + + d * + g ch + +in the seat of the chair, and d being the first one in the back. +This star was visible at noonday, and was brighter than any other +star in the heavens. In January, 1573, it was less bright than +Jupiter; in April it was below the second magnitude, and the last +of May it utterly disappeared. It was as variable in color as in +brilliancy. During its first two months, the period of greatest +brightness, it was dazzling white, then became yellow, and finally +as red as Mars or Aldebaran, and so expired. + +A bright star was seen very near to the place of the _Pilgrim_, +as the star of 1572 was called, in A.D. 945 and 1264. A star of +the tenth magnitude is now seen brightening slowly almost exactly +in the same place. It is possible that this is a variable star +of a period of about three hundred and ten years, and will blaze +out again about 1885. + +But we have had, within a few years, fine opportunities [Page 224] +to study, with improved instruments, two new stars; On the evening +of May 12th, 1866, a star of the second magnitude was observed in +the Northern Crown, where no star above the fifth magnitude had been +twenty-four hours before. In Argelander's chart a star of the tenth +magnitude occupies the place. May 13th it had declined to the third +magnitude, May 16th to the fourth, May 17th to the fifth, May 19th +to the seventh, May 31st to the ninth, and has since diminished to +the tenth. The spectroscope showed it to be a star in the usual +condition; but through the usual colored spectrum, crossed with +bright lines, shone four bright lines, two of which indicated +glowing hydrogen. Here was plenty of proof that an unusual amount of +this gas had given this sun its sudden flame. As the hydrogen burned +out the star grew dim. + +Two theories immediately presented themselves: First, that vast +volumes had been liberated from within the orb by some sudden breaking +up of the doors of its great deeps; or, second, this star had +precipitated upon itself, by attraction, some other sun or planet, +the force of whose impact had been changed into heat. + +Though we see the liberated hydrogen of our sun burst up with sudden +flame, it can hardly be supposed that enough could be liberated +at once to increase the light and heat one hundred-fold. + +In regard to the second theory, it is capable of proof that two +suns half as large as ours, moving at a velocity of four hundred +and seventy-six miles per second, would evolve heat enough to supply +the radiation of our sun for fifty million years. How could it be +possible for a sun like this newly blazing orb to cool off to such a +[Page 225] degree in a month? Besides, there would not be one chance +in a thousand for two orbs to come directly together. They would +revolve about each other till a kind of grazing contact of grinding +worlds would slowly kindle the ultimate heat. + +It is far more likely that this star encountered an enormous stream +of meteoric bodies, or perhaps absorbed a whole comet, that laid +its million leagues of tail as fuel on the central fire. Only let +it be remembered that the fuel is far more force than substance. +Allusion has already been made to the sudden brightening of our +sun on the first day of September, 1859. That was caused, no doubt, +by the fall of large meteors, following in the train of the comet +of 1843, or some other comet. What the effect would have been, had +the whole mass of the comet been absorbed, cannot be imagined. + +Another new star lately appeared in Cygnus, near the famous star +61--the first star in the northern hemisphere whose distance was +determined. It was first seen November 24th, 1876, as a third magnitude +star of a yellow color. By December 2d it had sunk to the fourth +magnitude, and changed to a greenish color. It had then three bright +hydrogen lines, the strong double sodium line, and others, which +made, it strongly resemble the spectrum of the chromosphere of our +sun. An entirely different result appeared in the fading of these +two stars. In the case of the star in the Crown, the extraordinary +light was the first to fade, leaving the usual stellar spectrum. In +the case of the star in Cygnus, the part of the spectrum belonging +to stellar light was the first to fade, leaving the bright lines; +that is, the gas of one gave way to regular starlight, and the +starlight [Page 226] of the other having faded, the regular light of +the glowing gas continued. By some strange oversight, no one studied +the star again for six months. In September and November, 1877, the +light of this star was found to be blue, and not to be starlight at +all. It had no rainbow spectrum, only one kind of rays, and hence +only one color. Its sole spectroscopic line is believed to be that +of glowing nitrogen gas. We have then, probably, in the star of +1876, a body shining by a feeble and undiscernible light, surrounded +by a discernible immensity of light of nitrogen gas. This is its +usual condition; but if a flight of meteors should raise the heat of +the central body so as to outshine the nebulous envelope, we should +have the conditions we discovered in November, 1876. But a rapid +cooling dissipates the observable light of all colors, and leaves +only the glowing gas of one color. + +_Movements of Stars._ + +We call the stars _fixed_, but motion and life are necessary to all +things. Besides the motion in the line of sight described already, +there is motion in every other conceivable direction. We knew Sirius +moved before we had found the cause. We know that our sun moves +back and forth in his easy bed one-half his vast diameter, as the +larger planets combine their influence on one side or the other. + +The sun has another movement. We find the stars in Hercules gradually +spreading from each other. Hercules's brawny limbs grow brawnier +every century. There can be but one cause: we are approaching that +quarter of the heavens. (See [Symbol], Fig. 72.) We are even [Page +227] able to compute the velocity of our approach; it is four miles +a second. The stars in the opposite quarter of the heavens in Argo +are drawing nearer together. + +This movement would have no effect on the apparent place of the +stars at either pole, if they were all equally distant; but it +must greatly extend or contract the apparent space between them, +since they are situated at various distances. + +Independent of this, the stars themselves are all in motion, but so +vast is the distance from which we observe them that it has taken +an accumulation of centuries before they could be made measurable. +A train going forty miles an hour, seen from a distance of two +miles, almost seems to stand still. Arcturus moves through space +three times as fast as the earth, but it takes a century to appear +to move the eighth part of the diameter of the moon. There is a +star in the Hunting Dogs, known as 1830 Groombridge, which has a +velocity beyond what all the attraction of the matter of the known +universe could give it. By the year 9000 it may be in Berenice's +Hair. + +Some stars have a common movement, being evidently related together. +A large proportion of the brighter stars between Aldebaran and +the Pleiades have a common motion eastward of about ten seconds +a century. All the angles marked by a, b, g, ch Orionis will be +altered in different directions; l is moving toward g. l and e +will appear as a double star. In A.D. 50,000 Procyon will be nearer +ch Orionis than Rigel now is, and Sirius will be in line with a and +ch Orionis. All the stars of the Great Dipper, except Benetnasch +and Dubhe, have a common motion somewhat in the direction [Page 228] +of Thuban (Fig. 67), while the two named have a motion nearly +opposite. In 36,000 years the end of the Dipper will have fallen out +so that it will hold no water, and the handle will be broken square +off at Mizar. "The Southern Cross," says Humboldt, "will not always +keep its characteristic form, for its four stars travel in different +directions with unequal velocities. At the present time it is not +known how many myriads of years must elapse before its entire +dislocation." + +These movements are not in fortuitous or chaotic ways, but are +doubtless in accordance with some perfect plan. We have climbed +up from revolving earth and moon to revolving planets and sun, +in order to understand how two or ten suns can revolve about a +common centre. Let us now leap to the grander idea that all the +innumerable stars of a winter night not only loan, but must revolve +about some centre of gravity. Men have been looking for a central +sun of suns, and have not found it. None is needed. Two suns can +balance about a point; all suns can swing about a common centre. +That one unmoving centre may be that city more gorgeous than Eastern +imagination ever conceived, whose pavement is transparent gold, +whose walls are precious stones, whose light is life, and where +no dark planetary bodies ever cast shadows. There reigns the King +and Lord of all, and ranged about are the far-off provinces of his +material systems. They all move in his sight, and receive power +from a mind that never wearies. + + + + +[Page 229] +XI. + +THE WORLDS AND THE WORD. + +"The worlds were framed by the word of God."--_Heb._ xi., 3. + +[Page 230] + "Mysterious night! when our first parent knew thee + From report divine, and heard thy name, + Did he not tremble for this lovely frame, + This glorious canopy of light and blue? + Yet, 'neath a curtain of translucent dew, + Bathed in the rays of the great setting flame, + Hesperus, with all the host of heaven, came, + And lo! creation widened in man's view. + Who could have thought such darkness lay concealed + Within thy beams, O Sun! Oh who could find, + Whilst fruit and leaf and insect stood revealed, + That to such countless worlds thou mad'st us blind! + Why do we then shun death with anxious strife? + If light conceal so much, wherefore not life?" + BLANCO WHITE. + + + + +[Page 231] +XI. + +_THE WORLDS AND THE WORD._ + +Men have found the various worlds to be far richer than they originally +thought. They have opened door after door in their vast treasuries, +have ascended throne after throne of power, and ruled realms of +increasing extent. We have no doubt that unfoldings in the future +will amaze even those whose expectations have been quickened by +the revealings of the past. What if it be found that the Word is +equally inexhaustible? + +After ages of thought and discovery we have come out of the darkness +and misconceptions of men. We believe in no serpent, turtle, or +elephant supporting the world; no Atlas holding up the heavens; +no crystal domes, "with cycles and epicycles scribbled o'er." What +if it be found that one book, written by ignorant men, never fell +into these mistakes of the wisest! Nay, more, what if some of the +greatest triumphs of modern science are to be found plainly stated +in a book older than the writings of Homer? If suns, planets, and +satellites, with all their possibilities of life, changes of flora +and fauna, could be all provided for, as some scientists tell us, +in the fiery star-dust of a cloud, why may not the same Author +provide a perpetually widening river of life in his Word? As we +believe He is perpetually present in his worlds, we know He has +[Page 232] promised to be perpetually present in his Word, making it +alive with spirit and life. + +The wise men of the past could not avoid alluding to ideas the falsity +of which subsequent discovery has revealed; but the writers of the +Bible did avoid such erroneous allusion. Of course they referred +to some things, as sunrise and sunset, according to appearance; +but our most scientific books do the same to-day. That the Bible +could avoid teaching the opposite of scientific truth proclaims +that a higher than human wisdom was in its teaching. + +That negative argument is strong, but the affirmative argument is +much stronger. The Bible declares scientific truth far in advance +of its discovery, far in advance of man's ability to understand +its plain declarations. Take a few conspicuous illustrations: + +The Bible asserted from the first that the present order of things +had a beginning. After ages of investigation, after researches in +the realms of physics, arguments in metaphysics, and conclusions +by the necessities of resistless logic, science has reached the +same result. + +The Bible asserted from the first that creation of matter preceded +arrangement. It was chaos--void--without form--darkness; arrangement +was a subsequent work. The world was not created in the form it +was to have; it was to be moulded, shaped, stratified, coaled, +mountained, valleyed, subsequently. All of which science utters +ages afterward. + +The Bible did not hesitate to affirm that light existed before +the sun, though men did not believe it, and used it as a weapon +against inspiration. Now we praise men for having demonstrated +the oldest record. + +[Page 233] +It is a recently discovered truth of science that the trata of +the earth were formed by the action of water, and the mountains +were once under the ocean. It is an idea long familiar to Bible +readers: "Thou coverest the earth with the deep as with a garment. +The waters stood above the mountains. At thy rebuke they fled; at +the voice of thy thunder they hasted away. The mountains ascend; +the valleys descend into the place thou hast founded for them." +Here is a whole volume of geology in a paragraph. The thunder of +continental convulsions is God's voice; the mountains rise by God's +power; the waters haste away unto the place God prepared for them. +Our slowness of geological discovery is perfectly accounted for by +Peter. "For of this they are _willingly ignorant_, that by the word +of God there were heavens of old, and land framed out of water, and +by means of water, whereby the world that then was, being overflowed +by water, perished." We recognize these geological subsidences, +but we read them from the testimony of the rocks more willingly +than from the testimony of the Word. + +Science exults in having discovered what it is pleased to call an +order of development on earth--tender grass, herb, tree; moving +creatures that have life in the waters; bird, reptile, beast, cattle, +man. The Bible gives the same order ages before, and calls it God's +successive creations. + +During ages on ages man's wisdom held the earth to be flat. Meanwhile, +God was saying, century after century, of himself, "He sitteth upon +the sphere of the earth" (Gesenius). + +Men racked their feeble wits for expedients to uphold [Page 234] the +earth, and the best they could devise were serpents, elephants, and +turtles; beyond that no one had ever gone to see what supported +them. Meanwhile, God was perpetually telling men that he had hung +the earth upon nothing. + +Men were ever trying to number the stars. Hipparchus counted one +thousand and twenty-two; Ptolemy one thousand and twenty-six; and +it is easy to number those visible to the naked eye. But the Bible +said, when there were no telescopes to make it known, that they +were as the sands of the sea, "innumerable." Science has appliances +of enumeration unknown to other ages, but the space-penetrating +telescopes and tastimeters reveal more worlds--eighteen millions +in a single system, and systems beyond count--till men acknowledge +that the stars are innumerable to man. It is God's prerogative "to +number all the stars; he also calleth them all by their names." + +Torricelli's discovery that the air had weight was received with +incredulity. For ages the air had propelled ships, thrust itself +against the bodies of men, and overturned their works. But no man +ever dreamed that weight was necessary to give momentum. During +all the centuries it had stood in the Bible, waiting for man's +comprehension: "He gave to the air its weight" (Job xxviii. 25). + +The pet science of to-day is meteorology. The fluctuations and +variations of the weather have hitherto baffled all attempts at +unravelling them. It has seemed that there was no law in their +fickle changes. But at length perseverance and skill have triumphed, +and a single man in one place predicts the weather and winds [Page +235] for a continent. But the Bible has always insisted that the +whole department was under law; nay, it laid down that law so +clearly, that if men had been willing to learn from it they might +have reached this wisdom ages ago. The whole moral law is not more +clearly crystallized in "Thou shalt love the Lord thy God with all +thy heart, and thy neighbor as thyself," than all the fundamentals +of the science of meteorology are crystallized in these words: "The +wind goeth toward the south (equator), and turneth about (up) unto +the north; it whirleth about continually, and the wind returneth +again according to his circuits (established routes). All the rivers +run into the sea; yet the sea is not full: unto the place from +whence the rivers come, thither they return again" (Eccles. i. 6, +7). + +Those scientific queries which God propounded to Job were unanswerable +then; most of them are so now. "Whereon are the sockets of the +earth made to sink?" Job never knew the earth turned in sockets; +much less could he tell where they were fixed. God answered this +question elsewhere. "He stretcheth the north (one socket) over +the empty place, and hangeth the earth upon nothing." Speaking +of the day-spring, God says the earth is _turned_ to it, as clay +to the seal. The earth's axial revolution is clearly recognized. +Copernicus declared it early; God earlier. + +No man yet understands the balancing of the clouds, nor the suspension +of the frozen masses of hail, any more than Job did. + +Had God asked if he had perceived the _length_ of the earth, many +a man to-day could have answered yes. But the eternal ice keeps +us from perceiving the _breadth_ [Page 236] of the earth, and shows +the discriminating wisdom of the question. + +The statement that the sun's going is from the end of the heaven, +and his circuit to the ends of it, has given edge to many a sneer +at its supposed assertion that the sun went round the earth. It +teaches a higher truth--that the sun itself obeys the law it enforces +on the planets, and flies in an orbit of its own, from one end of +heaven in Argo to the other in Hercules. + +So eminent an astronomer and so true a Christian as General Mitchell, +who understood the voices in which the heavens declare the glory of +God, who read with delight the Word of God em bodied in worlds, and +who fed upon the written Word of God as his daily bread, declared, +"We find an aptness and propriety in all these astronomical +illustrations, which are not weakened, but amazingly strengthened, +when viewed in the clear light of our present knowledge." Herschel +says, "All human discoveries seem to be made only for the purpose +of confirming more strongly the truths that come from on high, and +are contained in the sacred writings." The common authorship of +the worlds and the Word becomes apparent; their common unexplorable +wealth is a necessary conclusion. + +Since the opening revelations of the past show an unsearchable +wisdom in the Word, has that Word any prophecy concerning mysteries +not yet understood, and events yet in the future? There are certain +problems as yet insolvable. We have grasped many clews, and followed +them far into labyrinths of darkness, but not yet through into +light. + +We ask in vain, "What is matter?" No man can [Page 237] answer. We +trace it up through the worlds, till its increasing fineness, its +growing power, and possible identity of substance, seem as if the +next step would reveal its spirit origin. What we but hesitatingly +stammer, the Word boldly asserts. + +We ask, "What is force?" No man can answer. We recognize its various +grades, each subordinate to the higher--cohesion dissolvable by +heat; the affinity of oxygen and hydrogen in water overcome by +the piercing intensity of electric fire; rivers seeking the sea +by gravitation carried back by the sun; rock turned to soil, soil +to flowers; and all the forces in nature measurably subservient to +mind. Hence we partly understand what the Word has always taught +us, that all lower forces must be subject to that which is highest. +How easily can seas be divided, iron made to swim, water to burn, +and a dead body to live again, if the highest force exert itself +over forces made to be mastered. When we have followed force to +its highest place, we always find ourselves considering the forces +of mind and spirit, and say, in the words of the Scriptures, "God +is spirit." + +We ask in vain what is the end of the present condition of things. +We have read the history of our globe with great difficulty--its +prophecy is still more difficult. We have asked whether the stars +form a system, and if so, whether that system is permanent. We +are not able to answer yet. We have said that the sun would in +time become as icy cold and dead as the moon, and then the earth +would wander darkling in the voids of space. But the end of the +earth, as prophesied in the Word, is different: "The heavens will +pass away with [Page 238] a rushing noise, and the elements will be +dissolved with burning heat, and the earth and the works therein +will be burned up." The latest conclusions of science point the same +way. The great zones of uncondensed matter about the sun seem to +constitute a resisting medium as far as they reach. Encke's comet, +whose orbit comes near the sun, is delayed. This gives gravitation +an overwhelming power, and hence the orbit is lessened and a +revolution accomplished more quickly. Faye's comet, which wheels +beyond the track of Mars, is not retarded. If the earth moves +through a resisting substance, its ultimate fall into the sun is +certain. Whether in that far future the sun shall have cooled off, +or will be still as hot as to-day, Peter's description would +admirably portray the result of the impact. Peters description, +however, seems rather to indicate an interference of Divine power at +an appropriate time before a running down of the system at present +in existence, and a re-endowment of matter with new capabilities. + +After thousands of years, science discovered the true way to knowledge. +It is the Baconian way of experiment, of trial, of examining the +actual, instead of imagining the ideal. It is the acceptance of the +Scriptural plan. "If a man wills to do God's will, he shall know." +Oh taste and see! In science men try hypotheses, think the best they +can, plan broadly as possible, and then see if facts sustain the +theory. They have adopted the Scriptural idea of accepting a plan, +and then working in faith, in order to acquire knowledge. Fortunately, +in the work of salvation the plan is always perfect. But, in order +to make the trial under the most favorable circumstances, there +must be faith. The faith of [Page 239] science is amazing; its +assertions of the supersensual are astounding. It affirms a thousand +things that cannot be physically demonstrated: that the flight of a +rifle-ball is parabolic; that the earth has poles; that gages are +made of particles; that there are atoms; that an electric light +gives ten times as many rays as are visible; that there are sounds +to which we are deaf, sights to which we are blind; that a thousand +objects and activities are about us, for the perception of which we +need a hundred senses instead of five. These faiths have nearly all +led to sight; they have been rewarded, and the world's wealth of +knowledge is the result. The Word has ever asserted the +supersensuous, solicited man's faith, and ever uplifted every true +faith into sight. Lowell is partly right when he sings: + + "Science was Faith once; Faith were science now, + Would she but lay her bow and arrows by, + And aim her with the weapons of the time." + +Faith laid her bow and arrows by before men in pursuit of worldly +knowledge discovered theirs. + +What becomes of the force of the sun that is being spent to-day? +It is one of the firmest rocks of science that there can be no +absolute destruction of force. It is all conserved somehow. But +how? The sun contracts, light results, and leaps swiftly into all +encircling space. It can never be returned. Heat from stars invisible +by the largest telescope enters the tastimeter, and declares that +that force has journeyed from its source through incalculable years. +There is no encircling dome to reflect all this force back upon +its sources. Is it lost? Science, in defence of its own dogma, +should [Page 240] assign light a work as it flies in the space which +we have learned cannot be empty. There ought to be a realm where +light's inconceivable energy is utilized in building a grander +universe, where there is no night. Christ said, as he went out of +the seen into the unseen, "I go to prepare a place for you;" and +when John saw it in vision the sun had disappeared, the moon was +gone, but the light still continued. + +Science finds matter to be capable of unknown refinement; water +becomes steam full of amazing capabilities: we add more heat, superheat +the steam, and it takes on new aptitudes and uncontrollable energy. +Zinc burned in acid becomes electricity, which enters iron as a kind +of soul, to fill all that body with life. All matter is capable +of transformation, if not transfiguration, till it shines by the +light of an indwelling spirit. Scripture readers know that bodies +and even garments can be transfigured, be made astrapton (Luke xxiv. +4), shining with an inner light. They also look for new heavens and +a new earth endowed with higher powers, fit for perfect beings. + +When God made matter, so far as our thought permits us to know, +he simply made force stationary and unconscious. Thereafter he +moves through it with his own will. He can at any time change these +forces, making air solid, water and rock gaseous, a world a cloud, +or a fire-mist a stone. He may at some time restore all force to +consciousness again, and make every part of the universe thrill +with responsive joy. "Then shall the mountains and the hills break +forth before you into singing, and all the trees of the field clap +their hands." One of these changes is to come to the earth. [Page +241] Amidst great noise the heaven shall flee, the earth be burned +up, and all their forces be changed to new forms. Perhaps it will +not then be visible to mortal eyes. Perhaps force will then be made +conscious, and the flowers thereafter return our love as much as +lower creatures do now. A river and tree of life may be consciously +alive, as well as give life. Poets that are nearest to God are +constantly hearing the sweet voices of responsive feeling in nature. + + "For his gayer hours + She has a voice of gladness and a smile, + And eloquence of beauty; and she glides + Into his darker musings with a mild + And gentle sympathy, that steals away + Their sharpness ere he is aware." + +Prophets who utter God's voice of truth say, "The wilderness and +the solitary place shall be glad for holy men, and the desert shall +rejoice and blossom as the rose. It shall blossom abundantly and +rejoice, even with joy and singing." + +Distinguish clearly between certainty and surmise. The certainty is +that the world will pass through catastrophic changes to a perfect +world. The grave of uniformitarianism is already covered with grass. +He that creates promises to complete. The invisible, imponderable, +inaudible ether is beyond our apprehension; it transmits impressions +186,000 miles a second; it is millions of times more capable and +energetic than air. What may be the bounds of its possibility none +can imagine, for law is not abrogated nor designs disregarded as +we ascend into higher realms. Law works out more beautiful designs +with more absolute certainty. Why [Page 242] should there not be a +finer universe than this, and disconnected from this world +altogether--a fit home for immortal souls? It is a necessity. + +God filleth all in all, is everywhere omnipotent and wise. Why +should there be great vacuities, barren of power and its creative +outgoings? God has fixed the stars as proofs of his agency at some +points in space. But is it in points only? Science is proud of its +discovery that what men once thought to be empty space is more +intensely active than the coarser forms of matter can be. But in +the long times which are past Job glanced at earth, seas, clouds, +pillars of heaven, stars, day, night, all visible things, and then +added: "Lo! these are only the outlying borders of his works. What +a whisper of a word we hear of _Him!_ The thunder of his power +who can comprehend?" + +Science discovers that man is adapted for mastery in this world. +He is of the highest order of visible creatures. Neither is it +possible to imagine an order of beings generically higher to be +connected with the conditions of the material world. This whole +secret was known to the author of the oldest writing. "And God +blessed them, and God said unto them: Be fruitful, and multiply, +and replenish the earth, and subdue it: and have dominion over +the fish of the sea, and over the fowl of the air, and over every +living thing that moveth upon the earth." The idea is never lost +sight of in the sacred writings. And while every man knows he must +fail in one great contest, and yield himself to death, the later +portions of the divine Word offer him victory even here. The typical +man is commissioned to destroy even death, and make man a sharer +in the victory. [Page 243] Science babbles at this great truth of +man's position like a little child; Scripture treats it with a +breadth of perfect wisdom we are only beginning to grasp. + +Science tells us that each type is prophetic of a higher one. The +whale has bones prophetic of a human hand. Has man reached perfection? +Is there no prophecy in him? Not in his body, perhaps; but how his +whole soul yearns for greater beauty. As soon as he has found food, +the savage begins to carve his paddle, and make himself gorgeous with +feathers. How man yearns for strength, subduing animal and cosmic +forces to his will! How he fights against darkness and death, and +strives for perfection and holiness! These prophecies compel us to +believe there is a world where powers like those of electricity and +luminiferous ether are ever at hand; where its waters are rivers +of life, and its trees full of perfect healing, and from which all +unholiness is forever kept. What we infer, Scripture affirms. + +Science tells us there has been a survival of the fittest. Doubtless +this is so. So in the future there will be a survival of the fittest. +What is it? Wisdom, gentleness, meekness, brotherly kindness, and +charity. Over those who have these traits death hath no permanent +power. The caterpillar has no fear as he weaves his own shroud; for +there is life within fit to survive, and ere long it spreads its +gorgeous wings, and flies in the air above where once it crawled. Man +has had two states of being already. One confined, dark, peculiarly +nourished, slightly conscious; then he was born into another--wide, +differently nourished, and intensely [Page 244] conscious. He knows +he may be born again into a life wider yet, differently nourished, +and even yet more intensely conscious. Science has no hint how a +long ascending series of developments crowned by man may advance +another step, and make man isaggelos--equal to angels. But the +simplest teaching of Scripture points out a way so clear that a +child need not miss the glorious consummation. + +When Uranus hastened in one part of its orbit, and then retarded, +and swung too wide, men said there must be another attracting world +beyond; and, looking there, Neptune was found. So, when individual +men are so strong that nations or armies cannot break down their +wills; so brave, that lions have no terrors; so holy, that temptation +cannot lure nor sin defile them; so grand in thought, that men +cannot follow; so pure in walk, that God walks with them--let us +infer an attracting world, high and pure and strong as heaven. The +eleventh chapter of Hebrews is a roll-call of heroes of whom this +world was not worthy. They were tortured, not accepting deliverance, +that they might obtain a better resurrection. The world to come +influenced, as it were, the orbits of their souls, and when their +bodies fell off, earth having no hold on them, they sped on to +their celestial home. The tendency of such souls necessitates such +a world. + +The worlds and the Word speak but one language, teach but one set +of truths. How was it possible that the writers of the earlier +Scriptures described physical phenomena with wonderful sublimity, +and with such penetrative truth? They gazed upon the same heaven +that those men saw who ages afterward led the world in knowledge. +These latter were near-sighted, and absorbed [Page 245] in the +pictures on the first veil of matter; the former were far-sighted, +and penetrated a hundred strata of thickest material, and saw the +immaterial power behind. The one class studied the present, and made +the gravest mistakes; the other pierced the uncounted ages of the +past, and uttered the profoundest wisdom. There is but one +explanation. He that planned and made the worlds inspired the Word. + +Science and religion are not two separate departments, they are +not even two phases of the same truth. Science has a broader realm +in the unseen than in the seen, in the source of power than in the +outcomes of power, in the sublime laws of spirit than in the laws +of matter; and religion sheds its beautiful light over all stages +of life, till, whether we eat or whether we drink, or whatsoever +we do, we may do all for the glory of God. Science and religion +make common confession that the great object of life is to learn +and to grow. Both will come to see the best possible means, for +the attainment of this end is a personal relation to a teacher +who is the Way, the Truth, and the Life. + + + + +[Page 247] +XII. + +THE ULTIMATE FORCE. + +"In the beginning was the Word, and the Word was with God, and the +Word was God. The same was in the beginning with God. All things +became by him, and without him was not anything made that was made +* * * and by him all things stand together." + +[Page 248] + "O thou eternal one; whose presence blight + All space doth occupy--all motion guide-- + Thou from primeval nothingness didst call + First chaos, then existence. Lord, on thee + Eternity had its foundation: all + Sprung forth from thee--of light, joy, harmony, + Sole origin: all life, all beauty thine. + Thy word created all, and doth create; + Thy splendor fills all space with rays divine; + Thou art and wert, and shalt be glorious, great; + Life-giving, life-sustaining Potentate, + Thy chains the unmeasured universe surround-- + Upheld by thee, by thee inspired with breath." + DERZHAVIN. + + + + +[Page 249] +XII. + +_THE ULTIMATE FORCE._ + +The universe is God's name writ large. Thought goes up the shining +suns as golden stairs, and reads the consecutive syllables--all +might, and wisdom, and beauty; and if the heart be fine enough and +pure enough, it also reads everywhere the mystic name of love. Let +us learn to read the hieroglyphics, and then turn to the blazonry +of the infinite page. That is the key-note; the heavens and the earth +declaring the glory of God, and men with souls attuned listening. + +To what voices shall we listen first? Stand on the shore of a lake +set like an azure gem among the bosses of green hills. The patter +of rain means an annual fall of four cubic feet of water on every +square foot of it. It weighs two hundred and forty pounds to the +cubic foot, one hundred million tons on the surface of a little +sheet of water twenty miles long by three wide. Now, all that weight +of falling rain had to be lifted, a work compared to which taking +up mountains and casting them into the sea is pastime. All that +water had to be taken up before it could be cast down, and carried +hundreds of miles before it could be there. You have heard Niagara's +thunder; have stood beneath the falling immensity; seen it ceaselessly +poured from an infinite hand; felt that you would be ground to atoms +if you fell into that resistless flood. Well, all that infinity of +[Page 250] water had to be lifted by main force, had to be taken up +out of the far Pacific, brought over the Rocky Mountains; and the +Mississippi keeps bearing its wide miles of water to the Gulf, and +Niagara keeps thundering age after age, because there is power +somewhere to carry the immeasurable floods all the time the other +way in the upper air. + +But this is only the Alpha of power. Professor Clark, of Amherst, +Massachusetts, found that such a soft and pulpy thing as a squash +had so great a power of growth that it lifted three thousand pounds, +and held it day and night for months. It toiled and grew under the +growing weight, compacting its substance like oak to do the work. +All over the earth this tremendous power and push of life goes +on--in the little star-eyed flowers that look up to God only on +the Alpine heights, in every tuft of grass, in every acre of wheat, +in every mile of prairie, and in every lofty tree that wrestles +with the tempests of one hundred winters. But this is only the B +in the alphabet of power. + +Rise above the earth, and you find the worlds tossed like playthings, +and hurled seventy times as fast as a rifle-ball, never an inch +out of place or a second out of time. But this is only the C in +the alphabet of power. + +Rise to the sun. It is a quenchless reservoir of high-class energy. +Our tornadoes move sixty miles an hour, those of the sun twenty +thousand miles an hour. A forest on fire sends its spires of flame +one hundred feet in air, the sun sends its spires of flame two +hundred thousand miles. All our fires exhaust the fuel and burn +out. If the sun were pure coal, it would burn out in five thousand +years; and yet this sea of unquenchable [Page 251] flame seethes and +burns, and rolls and vivifies a dozen worlds, and flashes life along +the starry spaces for a million years without any apparent +diminution. It sends out its power to every planet, in the vast +circle in which it lies. It fills with light not merely a whole +circle, but a dome; not merely a dome above, but one below, and on +every side. At our distance of ninety-two and a half millions of +miles, the great earth feels that power in gravitation, tides, +rains, winds, and all possible life--every part is full of power. +Fill the earth's orbit with a circle of such receptive +worlds--seventy thousand instead of one--everyone would be as fully +supplied with power from this central source. More. Fill the whole +dome, the entire extent of the surrounding sphere, bottom, sides, +top, a sphere one hundred and eighty-five million miles in diameter, +and everyone of these uncountable worlds would be touched with the +same power as one; each would thrill with life. This is only the D +of the alphabet of power. And glancing up to the other suns, one +hundred, five hundred, twelve hundred times as large, double, +triple, septuple, multiple suns, we shall find power enough to go +through the whole alphabet in geometrical ratio; and then in the +clustered suns, galaxies, and nebulę, power enough still +unrepresented by single letters to require all combinations of the +alphabet of power. What is the significance of this single element +of power? The answer of science to-day is "correlation," the +constant evolution of one force from another. Heat is a mode of +motion, motion a result of heat. So far so good. But are we mere +reasoners in a circle? Then we would be lost men, treading our round +of death in a limitless forest. What is the ultimate? Reason [Page +252] out in a straight line. No definition of matter allows it to +originate force; only mind can do that. Hence the ultimate force is +always mind. Carry your correlation as far as you please--through +planets, suns, nebulę, concretionary vortices, and revolving +fire-mist--there must always be mind and will beyond. Some of that +willpower that works without exhaustion must take its own force and +render it static, apparent. It may do this in such correlated +relation that that force shall go on year after year to a thousand +changing forms; but that force must originate in mind. + +Go out in the falling rain, stand under the thunderous Niagara, +feel the immeasurable rush of life, see the hanging worlds, and +trace all this--the carried rain, the terrific thunder with God's bow +of peace upon it, and the unfailing planets hung upon nothing--trace +all this to the orb of day blazing in perpetual strength, but stop +not there. Who _made_ the sun? Contrivance fills all thought. _Who_ +made the sun? Nature says there is a mind, and that mind is Almighty. +Then you have read the first syllables, viz., being and power. + +What is the continuous relation of the universe to the mind from +which it derived its power? Some say that it is the relation of +a wound-up watch to the winder. It was dowered with sufficient +power to revolve its ceaseless changes, and its maker is henceforth +an absentee God. Is it? Let us have courage to see. For twenty +years one devotes ten seconds every night to putting a little force +into a watch. It is so arranged that it distributes that force +over twenty-four hours. In that twenty years more power has been +put into that watch than a horse could exert at once. But suppose +[Page 253] one had tried to put all that force into the watch at +once: it would have pulverized it to atoms. But supposing the +universe had been dowered with power at first to run its enormous +rounds for twenty millions of years. It is inconceivable; steel +would be as friable as sand, and strengthless as smoke, in such +strain. + +We have discovered some of the laws of the force we call gravitation. +But what do we know of its essence? How it appears to act we know a +little, what it is we are profoundly ignorant. Few men ever discuss +this question. All theories are sublimely ridiculous, and fail to +pass the most primary tests. How matter can act where it is not, +and on that with which it has no connection, is inconceivable. + +Newton said that anyone who has in philosophical matters a competent +faculty of thinking, could not admit for a moment the possibility +of a sun reaching through millions of miles, and exercising there +an attractive power. A watch may run if wound up, but how the +watch-spring in one pocket can run the watch in another is hard +to see. A watch is a contrivance for distributing a force outside +of itself, and if the universe runs at all on that principle, it +distributes some force outside of itself. + +Le Sage's theory of gravitation by the infinitive hail of atoms +cannot stand a minute, hence we come back as a necessity of thought +to Herschel's statement. "It is but reasonable to regard gravity +as a result of a consciousness and a will existent somewhere." +Where? I read an old book speaking of these matters, and it says +of God, He hangeth the earth upon nothing; he upholdeth constantly +all things by the word of his power. [Page 254] By him all things +consist or hold together. It teaches an imminent mind; an almighty, +constantly exerted power. Proof of this starts up on every side. +There is a recognized tendency in all high-class energy to +deteriorate to a lower class. There is steam in the boiler, but it +wastes without fuel. There is electricity in the jar, but every +particle of air steals away a little, unless our conscious force is +exerted to regather it. There is light in the sun, but infinite +space waits to receive it, and takes it swift as light can leap. We +said that if the sun were pure coal, it would burn out in five +thousand years, but it blazes undimmed by the million. How can it? +There have been various theories: chemical combustion, it has +failed; meteoric impact, it is insufficient; condensation, it is not +proved; and if it were, it is an intermediate step back to the +original cause of condensation. The far-seeing eyes see in the sun +the present active power of Him who first said, "Let there be +light," and who at any moment can meet a Saul in the way to Damascus +with a light above the brightness of the sun--another noon arisen on +mid-day; and of whom it shall be said in the eternal state of +unclouded brightness, where sun and moon are no more, "The glory of +the Lord shall lighten it, and the Lamb is the light thereof." + +But suppose matter could be dowered, that worlds could have a +gravitation, one of two things must follow: It must have conscious +knowledge of the position, exact weight, and distance of every +atom, mass, and world, in order to proportion the exact amount of +gravity, or it must fill infinity with an omnipresent attractive +power, pulling in myriads of places at nothing; in [Page 255] a few +places at worlds. Every world must exert an infinitely extended +power, but myriads of infinities cannot be in the same space. The +solution is, one infinite power and conscious will. + +To see the impossibility of every other solution, join in the long +and microscopic hunt for the ultimate particle, the atom; and if +found, or if not found, to a consideration of its remarkable powers. +Bring telescopes and microscopes, use all strategy, for that atom +is difficult to catch. Make the first search with the microscope: +we can count 112,000 lines ruled on a glass plate inside of an +inch. But we are here looking at mountain ridges and valleys, not +atoms. Gold can be beaten to the 1/340000 of an inch. It can be +drawn as the coating of a wire a thousand times thinner, to the +1/340000000 of an inch. But the atoms are still heaped one upon +another. + +Take some of the infusorial animals. Alonzo Gray says millions +of them would not equal in bulk a grain of sand. Yet each of them +performs the functions of respiration, circulation, digestion, +and locomotion. Some of our blood-vessels are not a millionth of +our size. What must be the size of the ultimate particles that +freely move about to nourish an animal whose totality is too small +to estimate? A grain of musk gives off atoms enough to scent every +part of the air of a room. You detect it above, below, on every +side. Then let the zephyrs of summer and the blasts of winter sweep +through that room for forty years, bearing out into the wide world +miles on miles of air, all perfumed from the atoms of that grain +of musk, and at the end of the forty years the weight of musk has +not appreciably diminished. [Page 256] Yet uncountable myriads on +myriads of atoms have gone. + +Our atom is not found yet. Many are the ways of searching for it +which we cannot stop to consider. We will pass in review the properties +with which materialists preposterously endow it. It is impenetrable +and indivisible, though some atoms are a hundred times larger than +others. Each has definite shape; some one shape, and some another. +They differ in weight, in quantity of combining power, in quality +of combining power. They combine with different substances, in +certain exact assignable quantities. Thus one atom of hydrogen +combines with eighty of bromine, one hundred and sixty of mercury, +two hundred and forty of boron, three hundred and twenty of silicon, +etc. Hence our atom of hydrogen must have power to count, or at +least to measure, or be cognizant of bulk. Again, atoms are of +different sorts, as positive or negative to electric currents. +They have power to take different shapes with different atoms in +crystallization; that is, there is a power in them, conscious or +otherwise, that the same bricks shall make themselves into stables +or palaces, sewers or pavements, according as the mortar varies. +"No, no," you cry out; "it is only according as the builder varies +his plan." There is no need to rehearse these powers much further; +though not one-tenth of the supposed innate properties of this +infinitesimal infinite have been recited--properties which are +expressed by the words atomicity, quantivilence, monad, dryad, +univalent, perissad, quadrivalent, and twenty other terms, each +expressing some endowment of power in this in visible atom. Refer +to one more presumed ability, an ability [Page 257] to keep +themselves in exact relation of distance and power to each other, +without touching. + +It is well known that water does not fill the space it occupies. +We can put eight or ten similar bulks of different substances into +a glass of water without greatly increasing its bulk, some actually +diminishing it. A philosopher has said that the atoms of oxygen +and hydrogen are probably not nearer to each other in water than +one hundred and fifty men would be if scattered over the surface +of England, one man to four hundred square miles. + +The atoms of the luminiferous ether are infinitely more diffused, +and yet its interactive atoms can give four hundred millions of +light-waves a second. And now, more preposterous than all, each +atom has an attractive power for every other atom of the universe. +The little mote, visible only in a sunbeam streaming through a +dark room, and the atom, infinitely smaller, has a grasp upon the +whole world, the far-off sun, and the stars that people infinite +space. The Sage of Concord advises you to hitch your wagon to a +star. But this is hitching all stars to an infinitesimal part of +a wagon. Such an atom, so dowered, so infinite, so conscious, is +an impossible conception. + +But if matter could be so dowered as to produce such results by +mechanism, could it be dowered to produce the results of intelligence? +Could it be dowered with power of choice without becoming mind? +If oxygen and hydrogen could be made able to combine into water, +could the same unformed matter produce in one case a plant, in +another a bird, in a third a man; and in each of these put bone, +brain, blood, and nerve in [Page 258] proper relations? Matter must +be mind, or subject to a present working mind, to do this. There +must be a present intelligence directing the process, laying the +dead bricks, marble, and wood in an intelligent order for a living +temple. If we do put God behind a single veil in dead matter, in all +living things he must be apparent and at work. If, then, such a +thing as an infinite atom is impossible, shall we not best +understand matter by saying it is a visible representation of God's +personal will and power, of his personal force, and perhaps +knowledge, set aside a little from himself, still possessed somewhat +of his personal attributes, still responsive to his will. What we +call matter may be best understood as God's force, will, knowledge, +rendered apparent, static, and unweariably operative. Unless matter +is eternal, which is unthinkable, there was nothing out of which the +world could be made, but God himself; and, reverently be it said, +matter seems to retain fit capabilities for such source. Is not this +the teaching of the Bible? I come to the old Book. I come to that +man who was taken up into the arcana of the third heaven, the holy +of holies, and heard things impossible to word. I find he makes a +clear, unequivocal statement of this truth as God's revelation to +him. "By faith," says the author of Hebrews, "we understand the +worlds were framed by the word of God, so that things which are seen +were not made of things which do appear." In Corinthians, Paul +says--But to us there is but one God, the Father, of whom [as a +source] are all things; and one Lord Jesus Christ, by whom [as a +creative worker] are all things. So in Romans he says--"For out of +him, and through him, and to him are all things, to whom be glory +forever. Amen." + +[Page 259] +God's intimate relation to matter is explained. No wonder the forces +respond to his will; no wonder pantheism--the idea that matter is +God--has had such a hold upon the minds of men. Matter, derived +from him, bears marks of its parentage, is sustained by him, and +when the Divine will shall draw it nearer to himself the new power +and capabilities of a new creation shall appear. Let us pay a higher +respect to the attractions and affinities; to the plan and power +of growth; to the wisdom of the ant; the geometry of the bee; the +migrating instinct that rises and stretches its wings toward a +provided South--for it is all God's present wisdom and power. Let +us come to that true insight of the old prophets, who are fittingly +called seers; whose eyes pierced the veil of matter, and saw God +clothing the grass of the field, feeding the sparrows, giving snow +like wool and scattering hoar-frost like ashes, and ever standing on +the bow of our wide-sailing world, and ever saying to all tumultuous +forces, "Peace, be still." Let us, with more reverent step, walk +the leafy solitudes, and say: + + "Father, thy hand + Hath reared these venerable columns: Thou + Did'st weave this verdant roof. Thou did'st look down + Upon the naked earth, and forthwise rose + All these fair ranks of trees. They in Thy sun + Budded, and shook their green leaves in Thy breeze. + + "That delicate forest flower, + With scented breath and looks so like a smile, + Seems, as it issues from the shapeless mould, + An emanation of the indwelling life, + A visible token of the unfolding love + That are the soul of this wide universe."--BRYANT. + +[Page 260] +Philosophy has seen the vast machine of the universe, wheel within +wheel, in countless numbers and hopeless intricacy. But it has +not had the spiritual insight of Ezekiel to see that they were +everyone of them full of eyes--God's own emblem of the omniscient +supervision. + +What if there are some sounds that do not seem to be musically +rhythmic. I have seen where an avalanche broke from the mountain side +and buried a hapless city; have seen the face of a cliff shattered +to fragments by the weight of its superincumbent mass, or pierced +by the fingers of the frost and torn away. All these thunder down +the valley and are pulverized to sand. Is this music? No, but it +is a tuning of instruments. The rootlets seize the sand and turn +it to soil, to woody fibre, leafy verdure, blooming flowers, and +delicious fruit. This asks life to come, partake, and be made strong. +The grass gives itself to all flesh, the insect grows to feed the +bird, the bird to nourish the animal, the animal to develop the +man. + +Notwithstanding the tendency of all high-class energy to deteriorate, +to find equilibrium, and so be strengthless and dead, there is, +somehow, in nature a tremendous push upward. Ask any philosopher, +and he will tell you that the tendency of all endowed forces is +to find their equilibrium and be at rest--that is, dead. He draws +a dismal picture of the time when the sun shall be burned out, +and the world float like a charnel ship through the dark, cold +voids of space--the sun a burned-out char, a dead cinder, and the +world one dismal silence, cold beyond measure, and dead beyond +consciousness. The philosopher has wailed a dirge without [Page 261] +hope, a requiem without grandeur, over the world's future. But +nature herself, to all ears attuned, sings pęans, and shouts to men +that the highest energy, that of life, does not deteriorate. + +Mere nature may deteriorate. The endowments of force must spend +themselves. Wound-up watches and worlds must run down. But nature +sustained by unexpendable forces must abide. Nature filled with +unexpendable forces continues in form. Nature impelled by a magnificent +push of life must ever rise. + +Study her history in the past. Sulphurous realms of deadly gases +become solid worlds; surplus sunlight becomes coal, which is reserved +power; surplus carbon becomes diamonds; sediments settle until +the heavens are azure, the air pure, the water translucent. If +that is the progress of the past, why should it deteriorate in the +future? + +There is a system of laws in the universe in which the higher have +mastery over the lower. Lower powers are constitutionally arranged +to be overcome; higher powers are constitutionally arranged for +mastery. At one time the water lies in even layers near the ocean's +bed, in obedience to the law or power of gravitation. At another +time it is heaved into mountain billows by the shoulders of the +wind. Again it flies aloft in the rising mists of the morning, +transfigured by a thousand rain bows by the higher powers of the +sun. Again it develops the enormous force of steam by the power of +heat. Again it divides into two light flying airs by electricity. +Again it stands upright as a heap by the power of some law in the +spirit realm, whose mode of working we are not yet large enough +[Page 262] to comprehend. The water is solid, liquid, gaseous on +earth, and in air according to the grade of power operating upon it. + +The constant invention of man finds higher and higher powers. Once +he throttled his game, and often perished in the desperate struggle; +then he trapped it; then pierced it with the javelin; then shot it +with an arrow, or set the springy gases to hurl a rifle-ball at +it. Sometime he may point at it an electric spark, and it shall +be his. Once he wearily trudged his twenty miles a day, then he +took the horse into service and made sixty; invoked the winds, +and rode on their steady wings two hundred and forty; tamed the +steam, and made almost one thousand; and if he cannot yet send his +body, he can his mind, one thousand miles a second. It all depends +upon the grade of power he uses. Now, hear the grand truth of nature: +as the years progress the higher grades of power increase. Either +by discovery or creation, there are still higher class forces to +be made available. Once there was no air, no usable electricity. +There is no lack of those higher powers now. The higher we go the +more of them we find. Mr. Lockyer says that the past ten years have +been years of revelation concerning the sun. A man could not read +in ten years the library of books created in that time concerning +the sun. But though we have solved certain problems and mysteries, +the mysteries have increased tenfold. + +We do not know that any new and higher forces have been added to +matter since man's acquaintance with it. But it would be easy to +add any number of them, or change any lower into higher. That is the +[Page 263] meaning of the falling granite that becomes soil, of the +pulverized lava that decks the volcano's trembling sides with +flowers; that is the meaning of the grass becoming flesh, and of all +high forces constitutionally arranged for mastery over lower. Take +the ore from the mountain. It is loose, friable, worthless in +itself. Raise it in capacity to cast-iron, wrought-iron, steel, it +becomes a highway for the commerce of nations, over the mountains +and under them. It becomes bones, muscles, body for the inspiring +soul of steam. It holds up the airy bridge over the deep chasm. It +is obedient in your hand as blade, hammer, bar, or spring. It is +inspirable by electricity, and bears human hopes, fears, and loves +in its own bosom. It has been raised from valueless ore. Change it +again to something as far above steel as that is above ore. Change +all earthly ores to highest possibility; string them to finest +tissues, and the new result may fit God's hand as tools, and thrill +with his wisdom and creative processes, a body fitted for God's +spirit as well as the steel is fitted to your hand. From this world +take opacity, gravity, darkness, bring in more mind, love, and God, +and then we will have heaven. An immanent God makes a plastic world. + +When man shall have mastered the forces that now exist, the original +Creator and Sustainer will say, "Behold, I create all things new." +Nature shall be called nearer to God, be more full of his power. +To the long-wandering Ęneas, his divine mother sometimes came to +cheer his heart and to direct his steps. But the goddess only showed +herself divine by her departure; only when he stood in desolation +did the hero know he had [Page 264] stood face to face with divine +power, beauty, and love. Not so the Christian scholars, the +wanderers in Nature's bowers to-day. In the first dawn of discovery, +we see her full of beauty and strength; in closer communion, we find +her full of wisdom; to our perfect knowledge, she reveals an +indwelling God in her; to our ardent love, she reveals an indwelling +God in us. + +But the evidence of the progressive refinements of habitation is no +more clear than that of progressive refinement of the inhabitant: +there must be some one to use these finer things. An empty house is +not God's ideal nor man's. The child may handle a toy, but a man +must mount a locomotive; and before there can be New Jerusalems +with golden streets, there must be men more avaricious of knowledge +than of gold, or they would dig them up; more zealous for love +than jewels, or they would unhang the pearly gates. The uplifting +refinement of the material world has been kept back until there +should appear masterful spirits able to handle the higher forces. +Doors have opened on every side to new realms of power, when men +have been able to wield them. If men lose that ability they close +again, and shut out the knowledge and light. Then ages, dark and +feeble, follow. + +Some explore prophecy for the date of the grand transformation +of matter by the coming of the Son of Man, for a new creation. A +little study of nature would show that the date cannot be fixed. +A little study of Peter would show the same thing. He says, "What +manner of persons ought ye to be, in all holy conversation and +godliness, looking for and hastening the coming [Page 265] of the +day of God, wherein the heavens being on fire shall be dissolved, +and the elements shall melt with fervent heat? Nevertheless we, +according to his promise, look for a new heaven and a new earth." + +The idea is, that the grand transformation of matter waits the +readiness of man. The kingdom waits the king. The scattered cantons +of Italy were only prostrate provinces till Victor Emanuel came, +then they were developed into united Italy. The prostrate provinces +of matter are not developed until the man is victor, able to rule +there a realm equal to ten cities here. Every good man hastens the +coming of the day of God and nature's renovation. Not only does +inference teach that there must be finer men, but fact affirms +that transformation has already taken place. Life is meant to have +power over chemical forces. It separates carbon from its compounds +and builds a tree, separates the elements and builds the body, +holds them separate until life withdraws. More life means higher +being. Certainly men can be refined and recapacitated as well as +ore. In Ovid's "Metamorphoses" he represents the lion in process of +formation from earth, hind quarters still clay, but fore quarters, +head, erect mane, and blazing eye--live lion--and pawing to get +free. We have seen winged spirits yet linked to forms of clay, +but beating the celestial air, endeavoring to be free; and we have +seen them, dowered with new sight, filled with new love, break +loose and rise to higher being. + +In this grand apotheosis of man which nature teaches, progress +lias already been made. Man has already outgrown his harmony with +the environment of mere matter. He has given his hand to science, and +been lifted up above the earth into the voids of infinite space. He +[Page 266] has gone on and on, till thought, wearied amidst the +infinities of velocity and distance, has ceased to note them. But he +is not content; all his faculties are not filled. He feels that his +future self is in danger of not being satisfied with space, and +worlds, and all mental delights, even as his manhood fails to be +satisfied with the materiel toys of his babyhood. He asks for an +Author and Maker of things, infinitely above them. He has seen +wisdom unsearchable, power illimitable; but he asks for personal +sympathy and love. Paul expresses his feeling: every creature--not +the whole creation--groaneth and travaileth in pain together until +now, waiting for the adoption--the uplifting from orphanage to +parentage--a translation out of darkness into the kingdom of God's +dear Son. He hears that a man in Christ is a new creation: old +things pass away, all things become new. There is then a possibility +of finding the Author of nature, and the Father of man. He begins +his studies anew. Now he sees that all lines of knowledge converge +as they go out toward the infinite mystery; sees that these +converging lines are the reins of government in this world; sees the +converging lines grasped by an almighty hand; sees a loving face and +form behind; sees that these lines of knowledge and power are his +personal nerves, along which flashes his will, and every force in +the universe answers like a perfect muscle. + +Then he asks if this Personality is as full of love as of power. +He is told of a tenderness too deep for tears, a love that has the +Cross for its symbol, and a dying cry for its expression: seeking +it, he is a new creation. He sees more wondrous things in the Word +than in the [Page 267] world. He comes to know God with his heart, +better than he knows God's works by his mind. + +Every song closes with the key-note with which it began, and the +brief cadence at the close hints the realms of sound through which +it has tried its wings. The brief cadence at the close is this: +All force runs back into mind for its source, constant support, +and uplifts into higher grades. + +Mr. Grove says, "Causation is the will, creation is the act, of God." +Creation is planned and inspired for the attainment of constantly +rising results. The order is chaos, light, worlds, vegetable forms, +animal life, then man. There is no reason to pause here. This is +not perfection, not even perpetuity. Original plans are not +accomplished, nor original force exhausted. In another world, free +from sickness, sorrow, pain, and death, perfection of abode is +offered. Perfection of inhabitant is necessary; and as the creative +power is everywhere present for the various uplifts and refinements +of matter, it is everywhere present with appropriate power for +the uplifting and refinement of mind and spirit. + + + + +[Page 269] +SUMMARY OF LATEST DISCOVERIES AND CONCLUSIONS. + +_Movements on the Sun._--The discovery and measurement of the up-rush, +down-rush, and whirl of currents about the sunspots, also of the +determination of the velocity of rotation by means of the spectroscope, +as described (page 53), is one of the most delicate and difficult +achievements of modern science. + +_Movement of Stars in Line of Sight_ (page 51).--The following +table shows this movement of stars, so far as at present known: + + --------------------------------------------------------------- +| APROACHING. || RECEDING. | +|------------------------------||-------------------------------| +| Map. | Name. | Rate || Map. | Name. | Rate | +| | | per sec. || | | per sec. | +|-------|-----------|----------||--------|-----------|----------| +|Fig. 71|Arcturus | 55 miles ||Fig. 69 |Sirius | 20 miles | +| " 72|Vega | 50 " ||Fr'piece|Betelguese | 22 " | +| " 73|a Cygni | 39 " || " |Rigel | 15 " | +| " 69|Pollux | 49 " ||Fig. 69 |Castor | 25 " | +| " 67|Dubhe | 46 " || " 70 |Regulus | 15 " | + --------------------------------------------------------------- + +_Sun's Appearance._--This was formerly supposed to be an even, +regular, dazzling brightness, except where the spots appeared. +But the sun's surface is now known to be mottled with what are +called rice grains or willow leaves. But the rice grains are as +large as the continent of America. The spaces between are called +pores. They constitute an innumerable number of small spots. This +appearance of the general surface is well portrayed in the cut +on page 92. + +_Close Relation between Sun and Earth._-Men always knew that the +earth received light from the sun. They subsequently discovered +that the earth was momentarily held by the power [Page 270] of +gravitation. But it is a recent discovery that the light is one of +the principal agents in chemical changes, in molecular grouping and +world-building, thus making all kinds of life possible (p. 30-36). +The close connection of the sun and the earth will be still farther +shown in the relation of sun-spots and auroras. One of the most +significant instances is related on page 19, when the earth felt the +fall of bolides upon the sun. Members of the body no more answer to +the heart than the planets do to the sun. + +_Hydrogen Flames._--It has been demonstrated that the sun flames +200,000 miles high are hydrogen in a state of flaming incandescence +(page 85). + +_Sun's Distance._--The former estimate, 95,513,794 miles, has been +reduced by nearly one-thirtieth. Lockyer has stated it as low as +89,895,000 miles, and Proctor, in "Encyclopędia Britannica," at +91,430,000 miles, but discovered errors show that these estimates +are too small. Newcomb gives 92,400,000 as within 200,000 miles +of the correct distance. The data for a new determination of this +distance, obtained from the transit of Venus, December 8th, 1874, +have not yet been deciphered; a fact that shows the difficulty +and laboriousness of the work. Meanwhile it begins to be evident +that observations of the transit of Venus do not afford the best +basis for the most perfect determination of the sun's distance. + +Since the earth's distance is our astronomical unit of measure, it +follows that all other distances will be changed, when expressed +in miles, by this ascertained change of the value of the standard. + +_Oxygen in the Sun._--In 1877 Professor Draper announced the discovery +of oxygen lines in the spectrum of the sun. The discovery was doubted, +and the methods used were criticised by Lockyer and others, but +later and more delicate experiments substantiate Professor Draper's +claim to the discovery. The elements known to exist in the sun +are salt, iron, hydrogen, [Page 271] magnesium, barium, copper, +zinc, cromium, and nickel. Some elements in the sun are scarcely, if +at all, discoverable on the earth, and some on the earth not yet +discernible in the sun. + +_Substance of Stars._--Aldebaran (_Frontispiece_) shows salt, magnesium, +hydrogen, calcium, iron, bismuth, tellurium, antimony, and mercury. +Some of the sun's metals do not appear. Stars differ in their very +substance, and will, no doubt, introduce new elements to us unknown +before. + +The theory that all nebulę are very distant clusters of stars is +utterly disproved by the clearest proof that some of them are only +incandescent gases of one or two kinds. + +_Discoveries of New Bodies._--Vulcan, the planet nearest the sun +(page 138). The two satellites of Mars were discovered by Mr. Hall, +U. S. Naval Observatory, August 11th, 1877 (page 161). "The outer +one is called Diemas; the inner, Phobus. + +Sir William Herschel thought he discovered six satellites of Uranus. +The existence of four of them has been disproved by the researches of +men with larger telescopes. Two new ones, however, were discovered +by Mr. Lassell in 1846. + +_Saturn's Rings_ are proved to be in a state of fluidity and contraction +(page 171). + +_Meteors and Comets._--The orbits of over one hundred swarms of +meteoric bodies are fixed: their relation to, and in some cases +indentity with, comets determined. Some comets are proved to be +masses of great weight and solidity (page 133). + +_Aerolites._-Some have a texture like our lowest strata of rocks. +There is a geology of stars and meteors as well as of the earth. M. +Meunier has just received the Lalande Medal from the Paris Academy +for his treatise showing that, so far as our present knowledge can +determine, some of these meteors once belonged to a globe developed +in true geological epochs, and which has been separated into fragments +by agencies with which we are not acquainted. + +[Illustration: Fig. 82.--Horizontal Pendulum.] + +_The Horizontal Pendulum._--This delicate instrument is [Page 272] +represented in Fig. 82. It consists of an upright standard, strongly +braced; a weight, _m_, suspended by the hair-spring of a watch, B D, +and held in a horizontal position by another watch-spring, A C. The +weight is deflected from side to side by the slightest influence. +The least change in the level of a base thirty-nine inches long that +could be detected by a spirit-level is 0".1 of an arc--equal to +raising one end 1/2068 of an inch. But the pendulum detects a +raising of one end 1/36000000 of an inch. To observe the movements +of the pendulum, it is kept in a dark room, and a ray of light is +directed to the mirror, _m_, and thence reflected upon a screen. +Thus the least movement may be enormously magnified, and read and +measured by the moving spot on the screen. It has been discovered +that when the sun rises it has sufficient attraction to incline this +instrument to the east; when it sets, to incline it to the west. The +same is true of the moon. When either is exactly overhead or +underfoot, of course there is no deflection. The mean deflection +caused by the moon at rising or setting is 0".0174; by the sun, +0".008. Great results are expected from this instrument hardly known +as yet: among others, whether gravitation acts instantly or consumes +time in coming from the sun. This will be shown by the time of the +change of the pendulum from east to west when the sun reaches the +zenith, and _vice versa_ when it crosses the nadir. The sun will be +best studied without light, in the quiet and darkness of some deep +mine. + +[Page 273] +_Light of Unseen Stars._--From careful examination, it appears +that three-fourths of the light on a fine starlight night comes +from stars that cannot be discerned by the naked eye. The whole +amount of star light is about one-eightieth of that of the full +moon. + +_Lateral Movements of Stars_, page 226-28. + +_Future Discoveries_--_A Trans-Neptunian Planet._--Professor Asaph +Hall says: "It is known to me that at least two American astronomers, +armed with powerful telescopes, have been searching quite recently for +a trans-Neptunian planet. These searches have been caused by the fact +that Professor Newcomb's tables of Uranus and Neptune already begin +to differ from observation. But are we to infer from these errors of +the planetary tables the existence of a trans-Neptunian planet? It +is possible that such a planet may exist, but the probability is, I +think, that the differences are caused by errors in the theories of +these planets. * * * A few years ago the remark was frequently made +that the labors of astronomers on the solar system were finished, and +that henceforth they could turn their whole attention to sidereal +astronomy. But to-day we have the lunar theory in a very discouraging +condition, and the theories of Mercury, Jupiter, Saturn, Uranus, +and Neptune all in need of revision; unless, indeed, Leverrier's +theories of the last two planets shall stand the test of observation. +But, after all, such a condition of things is only the natural +result of long and accurate series of observations, which make +evident the small inequalities in the motions, and bring to light +the errors of theory." + +Future discoveries will mostly reveal the laws and conditions of +the higher and finer forces. Already Professor Loomis telegraphs +twenty miles without wire, by the electric currents between mountains. +We begin to use electricity for light, and feel after it for a +motor. Comets and Auroras show its presence between worlds, and +in the interstellar spaces. Let another Newton arise. + +[Page 274] + SOME ELEMENTS OF THE SOLAR SYSTEM + ------------------------------------------------------------------------ +| | | | Mean Dist. | | | +| | | | from Sun. | | | +| | | |-------------------| Mean |Density.| +| | | | Earth's| |Diameter |[Earth] | +| Name. | Sign. | Masses. | Dist. | Millions |in Miles.| = 1. | +| | | | as 1. | of Miles.| | | +|-----------|--------|------------|--------|----------|---------|--------| +| Sun |[Symbol]| Unity | | | 860,000 | 0.255 | +| Mercury |[Symbol]|1/5000000(?)| 0.387 | 35-3/4| 2,992 | 1.21 | +| Venus |[Symbol]| 1/425000 | 0.723 | 66-3/4| 7,660 | 0.85 | +| Earth |[Symbol]| 1/326800 | 1. | 92-1/3| 7,918 | 1. | +| Mars |[Symbol]| 1/2950000 | 1.523 | 141 | 4,211 | 0.737 | +| Asteroids | (No.) | | | | | | +| Jupiter |[Symbol]| 1/1047 | 5.203 | 480 | 86,000 | 0.243 | +| Saturn |[Symbol]| 1/3501 | 9.538 | 881 | 70,500 | 0.133 | +| Uranus |[Symbol]| 1/22600 | 19.183 | 1771 | 31,700 | 0.226 | +| Neptune |[Symbol]| 1/19380 | 30.054 | 2775 | 34,500 | 0.204 | + ------------------------------------------------------------------------ + + ------------------------------------------------------------- +| | | Gravity | | | +| | Axial | at | | Orbital | +| | Revolu- | Surface. | Periodic | Velocity | +| Name. | tion | [Earth] | Time. | in Miles | +| | | = 1 | | per sec. | +|-----------|---------------|----------|-----------|----------| +| Sun | 25 to 26d | 27.71 | | | +| Mercury | 24h 5m(?) | 0.46 | 87.97d | 29.55 | +| Venus | 23h 21m(?) | 0.82 | 224.70d | 21.61 | +| Earth | 23h 56m 4s | 1. | 365.26d | 18.38 | +| Mars | 24h 37m 22.7s | 0.39 | 686.98d | 14.99 | +| Asteroids | | | | | +| Jupiter | 9h 55m 20s | 2.64 | 11.86yrs | 8.06 | +| Saturn | 10h 14m | 1.18 | 29.46yrs | 5.95 | +| Uranus | Unknown. | 0.90 | 84.02yrs | 4.20 | +| Neptune | Unknown. | 0.89 | 164.78yrs | 3.36 | + ------------------------------------------------------------- + +[Page 275] + EXPLANATION OF ASTRONOMICAL SYMBOLS. + + SIGNS OF THE ZODIAC + + 0. [Symbol] Aries 0° | VI. [Symbol] Libra 180° + I. [Symbol] Taurus 30 | VII. [Symbol] Scorpio 210 + II. [Symbol] Gemini 60 | VIII. [Symbol] Sagittarius 240 + III. [Symbol] Cancer 90 | IX. [Symbol] Capricornus 270 + IV. [Symbol] Leo 120 | X. [Symbol] Aquarius 300 + V. [Symbol] Virgo 150 | XI. [Symbol] Pisces 330 + + * * * * * + + [Symbol] Conjunction. | S. Seconds of Time. + [Symbol] Quadrature. | ° Degrees. + [Symbol] Opposition. | ' Minutes of Arc. + [Symbol] Ascending Node. | " Seconds of Arc. + [Symbol] Descending Node. | R. A. Right Ascension. + H. Hours. | Decl. or D. Declination. + M. Minutes of Time. | N. P. D. Dist. From North Pole. + + OTHER ABBREVIATIONS USED IN THE ALMANAC. + +S., South, _i.e._, crosses the meridian; M., morning; A, Afternoon; +Gr. H. L. N., greatest heliocentric latitude north, _i.e._, greatest +distance north of the ecliptic, as seen from the sun. [Symbols] +Inf., inferior conjunction; Sup., superior conjunction. + + GREEK ALPHABET USED INDICATING THE STARS. + + a, alpha. | ae, eta. | n, nu. | t, tau. + b, beta. | th, theta. | x, xi. | u, upsilon. + g, gamma. | i, iota. | o, omicron. | ph, phi. + d, delta. | k, kappa. | p, pi. | ch, chi. + e, epsilon. | l, lambda. | r, rho. | ps, psi. + z, zeta. | m, mu. | s, sigma. | o, omega. + + + + +[Page 276] +CHAUTAUQUA OUTLINE FOR STUDENTS. + +As an aid to comprehension, every student should draw illustrative +figures of the various circles, planes, and situations described. +(For example, see Fig. 45, page 112.) As an aid to memory, the +portion of this outline referring to each chapter should be examined +at the close of the reading, and this mere sketch filled up to a +perfect picture from recollection. + +I. _Creative Processes._--The dial-plate of the sky. Cause or different +weights--on sun, moon. Two laws of gravity. Inertia. Fall of earth +to sun per second. Forward motion. Elastic attraction. Perturbation +of moon; of Jupiter and Saturn. Oscillations of planets. + +II. _Light._--From condensation. Number of vibrations of red; violet. +Thermometer against air. Aerolite against earth. Two bolides against +the sun. Large eye. Velocity of light. Prism. Color means different +vibrations. Music of light. Light reports substance of stars. Force +of; bridge, rain, dispersion, intensities, reflection, refraction, +decomposition. + +III. _Astronomical Instruments._--Refracting telescope. Reflecting; +largest. Spectroscope. Spectra of sun, hydrogen, sodium, etc. E +made G by approach; C by departure. Stars approach and recede. + +IV. _Celestial Measurements._-Place and time by stars. Degrees, +minutes, seconds. Mapping stars. Mural circle. Slow watch. Hoosac +Tunnel. Fine measurements. Sidereal time. Spider-lines. Personal +equation. Measure distance--height. Ten-inch base line. Parallax +of sun, stars. Longitude at sea. Distance of Polaris, a Centauri, +61 Cygni. Orbits of asteroids. + +V. _The Sun._--World on fire. Apparent size from planets. Zodiacal +light. Corona. Hydrogen--how high? Size. How many earths? Spots: +1. Motion; 2. Edges; 3. Variable; 4. Periodic; 5. Cyclonic; 6. +Size; 7. Velocities. What the sun does. Experiments. + +VI. _The Planets from Space._--North Pole. Speed. Sizes. Axial +revolution. Man's weight on. Seasons. Parallelism of axis. Earth +near [Page 277] sun in winter. Plane of ecliptic. Orbits inclined +to. Earth rotates. Proof. Sun's path among stars. Position of +planets. Motion--direct, retrograde. Experiments. + +VII. _Meteors._--Size; number; cause of; above earth; velocity; +colors; number in space; telescopic view of. Aerolites: Systems +of; how many known. Comets: Orbits; number of comets; Halley's; +Biela's lost; Encke's. Resisting medium. Whence come comets? Composed +of what? Amount of matter in. [Symbol]. + +VIII. _The Planets._--How many? Uranus discovered? Neptune? Asteroids? +Vulcan? Distance from sun. Periodic time. Mercury: Elements; shapes, +as seen from earth; transits. Venus: Elements; seen by day; how +near earth? how far from? phases; Galileo. Earth: Elements; in +space; Aurora; balance of forces. Tides: Main and subsidiary causes; +eastern shores; Mediterranean Sea. Moon: Elements; hoax; moves east; +see one side; three causes help to see more than half. Revolution: +Why twenty-nine and a half days: heat--cold; how much light? Craters +and peaks lighted; measured. Eclipses--Why not every new and full +moon? Periodicity. Mars: Elements; how near earth? How far from? +Apparent size; ice-fields; which end most? Satellites--Asteroids: +How found? When? By whom? How many? Jupiter: Elements; trade-winds; +how much light received? Own heat. Satellites: How many? Colors. +Saturn: Elements; habitability; rings; flux; satellites. Uranus: +Elements; discoverer; seen by; moon's motion. Neptune: Elements; +discovered by; how? Review system. + +IX. _The Nebular Hypothesis._--State it; facts confirmatory. +Objections--1. Heat; 2. Rotation; 3. Retrograde; 4. Martial moons; +5. Star of 1876. Evolution: Gaps in; conclusion. + +X. _The Stellar System._-Motto. Man among stars; open page; starry +poem; stars located; named. Thuban. Etanin. Constellations: Know +them; number of stars; double; e Lyrę, Sirius, Procyon, Castor, +61 Cygni, g Virginis. Colored stars; change color. Clusters: Two +theories. Nebulę: Two visible; composed of; shapes; where? Variable +stars. Sun. b Lyrę, Mira, Betelguese, Algol; cause. Temporary; +1572. New star of 1866: Two theories. Star of 1876. Movements of +stars; Sirius; sun; 1830 Groombridge. Stars near Pleiades: Orion, +Great Dipper, Southern Cross. Centre of gravity. + +XI. _The Worlds and the Word._--Rich. Number. Erroneous allusions. +Truth before discovery: 1. A beginning; 2. Creation before arrangement; +3. Light before sun; 4. Mountains under water; 5. Order of +development; [Page 278] 6. Sphere of earth; 7. How upheld; 8. Number +of stars; 9. Weight of air; 10. Meteorology; 11. Queries to Job; 12. +Sun to end of heaven; 13. View of Mitchell; 14. Herschel. What is +matter? Force? End of earth. Way to knowledge. Work of light. +Transfiguration of matter. Uniformitarianism. A whisper of Him. Man +for mastery. Each a type of higher. Survival of fittest. Uranus. +Worlds and Word one language. + +XII. _The Ultimate Force._--Universe shows power: 1. Rain; Niagara; +2. Vegetable growth; 3. Worlds carried; 4. Sun; fill dome with worlds; +5. Double suns; 6. Galaxies. Correlation. What ultimate? Mind and +will. What continuous relation? Watch. Theories of gravitation: +Newton's, Le Sage's, Bible's. High-class energy deteriorates. Search +for atoms: 1. Microscope; 2. Gold; 3. Infusoria; 4. Musk. Properties +of atoms: 1. Impenetrable; 2. Indivisible; 3. Shape; 4. Quality; 5. +Crystallization; 6. Not touch each other; 7. Active; 8. Attractive; +9. Intelligent. Whose? Relation of matter to God; rock to soil. +Push upward. Highest has mastery. Man advances by highest. Matter +recapacitated. Refined habitations. Inhabitants. All force leads +back to mind. Personal and infinite. + + + + +[Page 279] +GLOSSARY OF ASTRONOMICAL TERMS AND INDEX. + +ABBREVIATIONS used in astronomies, 275. +ABERRATION OF LIGHT (_a wandering away_), an apparent + displacement of a star, owing to the progressive motion of light + combined with that of the earth and its orbit, 199. +AEROLITE (_air-stone_), 122. +AIR, refraction of the, 40. +ALGOL, the variable star, 222. +ALMANAC, Nautical, 71; explanation of signs used, 275. +ALPHABET, Greek, 275. +ALTITUDE, angular elevation of a body above the horizon. +ANGLE, difference in directions of two straight lines that meet. +ANNULAR (_ring-shaped_) ECLIPSES, 158; nebulę, 218, 220. +APHELION, the point in an orbit farthest from the sun. +APOGEE, the point of an orbit which is farthest from the earth. +APSIS, plural _apsides_, the line joining the aphelion and + perihelion points; or the major axis of elliptical orbits. +ARC, a part of a circle. +ASCENSION, RIGHT, the angular distance of a heavenly body from + the first point of Aries, measured on the equator. +ASTEROIDS (_star-like_), 162; orbits of interlaced, 74. +ASTRONOMICAL INSTRUMENTS, 43. +ASTRONOMY, use of, 57. +ATOM, size of, 255; power of, 256. +AURORA BOREALIS, 143. +AXIS, the line about which a body rotates. +AZIMUTH, the angular distance of any point or body in the horizon + from the north or south points. +BAILEY'S BEADS, dots of light on the edge of the moon seen in a + solar eclipse, caused by the moon's inequalities of surface. +BASE LINE, 68. +BIELA'S COMET, 129. +BINARY SYSTEM, a double star, the component parts of which + revolve around their centre of gravity. +BODE'S LAW of planetary distances is no law at all, but a study + of coincidences. +BOLIDES, small masses of matter in space. They are usually + called meteors when luminous by contact with air, 120. +[Page 280] +CELESTIAL SPHERE, the apparent dome in which the heavenly bodies + seem to be set; appears to revolve, 3. +CENTRE OF GRAVITY, the point on which a body, or two or more + related bodies, balances. +CENTRIFUGAL FORCE (_centre fleeing_). +CHROMOLITHIC PLATE of spectra of metals, to face 50. +CIRCUMPOLAR STARS, map of north, 201. +COLORS OF STARS, 214. +COLURES, the four principal meridians of the celestial sphere + passing from the pole, one through each equinox, and one through + each solstice. +COMETS, 126; Halley's, 128; Biela's lost, 129; Encke's, 130; + constitution of, 131; will they strike the earth? 133. +CONJUNCTION. Two or more bodies are in conjunction when they + are in a straight line (disregarding inclination of orbit) with the + sun. Planets nearer the sun than the earth are in inferior + conjunction when they are between the earth and the sun; superior + conjunction when they are beyond the sun. +CONSTELLATION, a group of stars supposed to represent some figure: + circumpolar, 201; equatorial, for December, 202; for January, 203; + April, 204; June, 205; September, 206; November, 207; southern + circumpolar, 208. +CULMINATION, the passage of a heavenly body across the meridian + or south point of a place; it is the highest point reached in its + path. +CUSP, the extremities of the crescent form of the moon or an + interior planet. +DECLINATION, the angular distance of a celestial body north or south + from the celestial equator. +DEGREE, the 1/360 part of a circle. +DIRECT MOTION, a motion from west to east among stars. +DISK, the visible surface of sun, moon, or planets. +DISTANCE OF STARS, 70. +DOUBLE STARS, 210. +EARTH, revolution of, 109; in space, 142; irregular figure, 145. +ECCENTRICITY OF AN ELLIPSE, the distance of either focus from centre + divided by half the major axis. +ECLIPSE (_a disappearance_), 157. +ECLIPTIC, the apparent annual path of the sun among the stars; + plane of, 106. +EGRESS, the passing of one body off the disk of another. +ELEMENTS, the quantities which determine the motion of a planet: + data for predicting astronomical phenomena; table of solar, 274. +ELEMENTS, chemical, present in the sun, 270. +ELONGATION, the angular distance of a planet from the sun. +EMERSION, the reappearance of a body after it has been eclipsed or + occulted by another. +[Page 281] +EQUATOR, terrestrial, the great circle half-way between the poles of + the earth. When the plane of this is extended to the heavens, + the line of contact is called the celestial equator. +EQUINOX, either of the points in which the sun, in its apparent + annual course among the stars, crosses the equator, making days + and nights of equal length. +EVOLUTION, materialistic, 182; insufficient, 189. +FIZEAU determines the velocity of light, 23. +FORCES, delicate balance of, 144. +GALILEO, construction of his telescope, 43. +GEOCENTRIC, a position of a heavenly body as seen or measured from + the earth's centre. +GEODESY, the art of measuring the earth without reference to the + heavenly bodies. +GOD, relation of, to the universe, 258. +GRAVITATION, laws of, 6; extends to the stars, 13; theories of, 253. +GRAVITY on different bodies, 6, 274. +HELICAL, rising or setting of a star, as near to sunrise or sunset + as it can be seen. +HELIOCENTRIC, as seen from the centre of the sun. +HOOSAC TUNNEL, example of accuracy, 62. +HORIZONTAL PENDULUM, 272. +IMMERSION, the disappearance of one body behind another, or in + its shadow. +INCLINATION OF AN ORBIT, the angle between its plane and the plane + of the ecliptic. +INFERIOR CONJUNCTION, when an interior planet is between the earth + and the sun. +JUPITER, apparent path of, in 1866, 112; elements of, 164; + satellites of, 165; positions of satellites, 166; elements of satellites, + 166; the Jovian system, 167. +KEPLER'S LAWS--1st, that the orbits of planets are ellipses, having + the sun or central body in one of the foci; 2d, the radius-vector + passes over equal spaces in equal times; 3d, the squares of the + periodic times of the planets are in proportion to the cubes of + their mean distances from the sun. +LATITUDE, the angular distance of a heavenly body from the ecliptic. +LIGHT, the child of force, 17; number of vibrations of, 18, 25; + velocity of, 22; undulatory and musical, 26; chemical force of, 30; + experiments with, 37; approach and departure of a light-giving + body measured, 51; aberration of, 199. +LIMB, the edge of the disk of the moon, sun, or a planet. +LONGITUDE. If a perpendicular be dropped from a body to the + ecliptic, its celestial longitude is the distance of the foot of the + perpendicular from the vertical equinox, counted toward the east; + mode of ascertaining terrestrial, 72. +MAGELLANIC CLOUDS, 208. +[Page 282] +MARS, 159; snow spots of, 160; satellites of, 161. +MASS, the quantity of matter a body contains. +MEAN DISTANCE OF A PLANET, half the sum of the aphelion and + perihelion distances. +MEASUREMENTS, celestial, 57. +MERCURY, 138. +MERIDIAN, terrestrial, of a place, a great circle of the heavens + passing through the poles, the zenith, and the north and south points + of the horizon; celestial, any great circle passing from one pole + to the other. +METEORS, 119; swarm of, meeting the earth, 118; explosion of, 120; + systems of, 123; relation of, to comets, 124. +MICROMETER, any instrument for the accurate measurement of very + small distances or angles. +MIND, origin of force, 252; continuous relation of, to the + universe, 252. +MILKY WAY, 210, 215. +MIRA, the Wonderful, 221. +MOON, the, 151; greatest and least distance from the earth, 10; + telescopic appearance of, 155. +MURAL CIRCLE, 61. +NADIR, the point in the celestial sphere directly beneath our feet, + opposite to zenith. +NEBULĘ, 217. +NEBULAR HYPOTHESIS, not atheistic, 182; stated, 182; confirmatory + facts, 183; objections to, 185. +NEPTUNE, elements of, 175. +NODE, the point in which an orbit intersects the ecliptic, or + other plane of reference; ascending, descending, line of, 107. +OCCULTATION, the hiding of a star, planet, or satellite by the + interposition of a nearer body of greater angular magnitude. +OPPOSITION. A superior planet is in opposition when the sun, + earth, and the planet are in a line, the earth being in the middle. +ORBIT, the path of a planet, comet, or meteor around the sun, or of + a satellite around a primary; inclination of, 106; earth's, seen + from the stars, 70. +OUTLINE FOR STUDENTS, 276. +PARALLAX, the difference of direction of a heavenly body as seen + from two points, as the centre of the earth and some point of its + surface, 69. +PARALLELS, imaginary circles on the earth or in the heavens parallel + to the equator, having the poles for their centre. +PERIGEE, nearest the earth; said of a point in an orbit. +PERIHELION, the point of an orbit nearest the sun. +PERIODIC TIME, time of a planet's, comet's, or satellite's + revolution. +PERSONAL EQUATION, 65. +PERTURBATION, the effect of the attractions of the planets or other +[Page 283] + bodies upon each other, disturbing their regular motion; of Saturn + and Jupiter, 11; of asteroids, 13; of Uranus and Neptune, 176. +PHASES, the portions of the illuminated half of the moon or + interior planet, as seen from the earth, called crescent, full, and + gibbous. +PHOTOSPHERE of the sun, 89. +PLANET (_a wanderer_), as seen from space, 99; speed of, 101; + size of, 102; movements retrograde and direct, 112. +POINTERS, the, 197. +POLE, NORTH, movement of, 198. +POLES, the extremities of an imaginary line on which a celestial + body rotates. +QUADRANT, the fourth part of the circumference of a circle, or 90°. +QUADRATURE, a position of the moon or other body when 90° from + the sun. +RADIANT POINT, that point of the heavens from which meteors seem + to diverge, 118. +RADIUS-VECTOR, an imaginary line joining the sun and a planet or + comet in any part of its orbit. +RAIN, weight of, 249. +REFLECTING TELESCOPE, 44. +REFRACTING TELESCOPE, 43. +REFRACTION, a bending of light by passing through any medium, as + air, water, prism. +RETROGRADE MOTION, the apparent movement of a planet from east + to west among the stars. +REVOLUTION, the movement of bodies about their centre of gravity. +ROTATION, the motion of a body around its axis. +SATELLITES, smaller bodies revolving around planets and stars. +SATURN, elements of, 167; revolution of, 168; rings of, 169; + decreasing, 171; nature of, 171; satellites of, 172. +SEASONS, of the earth, 102; of other planets, 105. +SELENOGRAPHY (_lunography_), a description of the moon's + surface. +SIGNS OF THE ZODIAC, the twelve equal parts, of 30° each, into + which the zodiac is divided. +SOLAR SYSTEM, view of, 100, 177. +SOLSTICES, those points of the ecliptic which are most distant from + the equator. The sun passes one about June 21st, and the other + about December 21st, giving the longest days and nights. +SPECTROSCOPE, 46. +SPECTRUM OF SUN AND METALS, 50. +STARS, chemistry of, 28; distance of, 70-73; mode of naming, 196; + number of, 210; double and multiple, 210; colored, 214; clusters + of, 215; variable, 220; temporary, new, and lost, 223; movements + of lateral, 226; in line of sight, 269. +STATIONARY POINTS, places in a planet's orbit at which it has no + motion among the stars. +[Page 284] +STELLAR SYSTEM, the, 195. +SUMMARY OF RECENT DISCOVERIES, 269. +SUN, fall of two meteoric bodies into, 19; light from contraction + of, 20; as seen from planets, 79; corona, 81; hydrogen flames of, 84; + condition of, 89; spots, 90; experiments, 95; apparent path among + the stars, 111; power of, 250. +SYMBOLS USED IN ASTRONOMY, 275. +TELESCOPE, refracting, 43; reflecting, 44; Cambridge equatorial, 46. +TELESCOPIC WORK, clusters, 210; double stars, 212. +TEMPORARY STARS, 223. +TERMINATOR, the boundary-line between light and darkness on the + moon or a planet. +TIDES, 146. +TRANSIT, the passage of an object across some fixed line, as the + meridian, or between the eye of an observer and an apparently + larger object, as that of Mercury or Venus over the disk of the + sun, and the satellites of Jupiter over its disk; of a star, 65. +ULTIMATE FORCE, the, 249. +URANUS, elements of, 173; moons of, retrograde, 174; perturbed by + Neptune, 176. +VARIABLE STARS, 220. +VENUS, 139. +VERNIER, a scale to measure very minute distances. +VERTICAL CIRCLE, one that passes through the zenith and nadir of + the celestial sphere. The prime vertical circle passes through the + east and west points of the horizon. +VULCAN, discovery of, 137. +WORLDS, THE, AND THE WORD, teach the same truth, 231-245. +YEAR, the, length of, on any planet, is determined by the periodic + time. +ZENITH, the point in the celestial sphere directly overhead. +ZODIAC, a belt 18° wide encircling the heavens, the ecliptic being + the middle. In this belt the larger planets always appear. In + the older astronomy it was divided into twelve parts of 30° + each, called signs of the zodiac. +ZODIACAL LIGHT, 80. + + + + +TO FIND THE STARS IN THE SKY. + +Detach any of the following maps, appropriate to the time of year, +hold it between you and a lantern out-of-doors, and you have an +exact miniature of the sky. Or, better, cut squares of suitable +sizes from the four sides of a box; put a map over each aperture; +provide for ventilation, and turn the box over a lamp or candle +out-of-doors. Use an opera glass to find the smaller stars, if +one is accessible. + +[Illustration: Circumpolar Constellations. Always visible. In this +position.--January 20th, at 10 o'clock; February 4th, at 9 o'clock; +and February 19th, at 8 o'clock.] + +[Illustration: Algol is on the Meridian, 51° South of Pole.--At 10 +o'clock, December 7th; 9 o'clock, December 22d; 8 o'clock, January +5th.] + +[Illustration: Capella (45° from Pole) and Rigel (100°) are on +the Meridian at 8 o'clock February 7th, 9 o'clock January 22d, and +at 10 o'clock January 7th.] + +[Illustration: Regulus comes on the Meridian, 79° south from the +Pole, at 10 o'clock March 23d, 9 o'clock April 8th, and at 8 o'clock +April 23d.] + +[Illustration: Arcturus comes to the Meridian, 70° from the Pole, +at 10 o'clock May 25th, 9 o'clock June 9th, and at 8 o'clock June +25th.] + +[Illustration: Altair comes to the Meridian, 82° from the Pole, +at 10 o'clock P.M. August 18th, at 9 o'clock September 2d, and +at 8 o'clock September 18th.] + +[Illustration: Fomalhaut comes to the Meridian, only 17° from the +horizon, at 8 o'clock November 4th.] + + + + + + +End of Project Gutenberg's Recreations in Astronomy, by Henry Warren + +*** END OF THIS PROJECT GUTENBERG EBOOK RECREATIONS IN ASTRONOMY *** + +***** This file should be named 15620-8.txt or 15620-8.zip ***** +This and all associated files of various formats will be found in: + https://www.gutenberg.org/1/5/6/2/15620/ + +Produced by Robert J. Hall. + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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