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| author | Roger Frank <rfrank@pglaf.org> | 2025-10-15 04:47:11 -0700 |
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| committer | Roger Frank <rfrank@pglaf.org> | 2025-10-15 04:47:11 -0700 |
| commit | 7496b56dbf852fa94ecb487b184da59fbb0ebae3 (patch) | |
| tree | 85657d94036fb66a201e3788a01a45dcabbe7219 /15620-h | |
Diffstat (limited to '15620-h')
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diff --git a/15620-h/15620-h.htm b/15620-h/15620-h.htm new file mode 100644 index 0000000..7309d4e --- /dev/null +++ b/15620-h/15620-h.htm @@ -0,0 +1,11662 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> +<html lang="en"> + +<head> + <title>Recreations in Astronomy</title> + <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> + <meta name="keywords" content="astronomy planet star moon comet"> + <meta name="author" content="Henry WHite Warren"> + <meta name="rating" content="General"> + <meta name="robots" content="all"> + <style type="text/css"> + + body { background: white; + margin-left: 15%; margin-right: 15%; } + h1 { text-align: center; margin-top: 4em; } + h2 { text-align: center; margin-top: 4em; } + h3 { text-align: center; margin-top: 1em; } + hr {width: 80%; margin-top: 2em; margin-bottom: 2em;} + p.indent { text-indent: 3mm; text-align: justify; } + p.bquote { margin-left: 4em; margin-right: 4em; } + p.subtitle { text-align: center; font-size: large; } + p.author { text-align: center; font-size: large; } + p.center { text-align: center; } + p.title { text-align: center; font-size: x-large; } + p.footnote { font-size: smaller; } + p.index { text-indent: -1em; text-align: justify; + margin-left: 1em; margin-top: 0em; + margin-bottom: 0em; } + table.left { float: left; margin: 4px; } + table.center { margin-left: auto; margin-right: auto; } + table.right { float: right; margin: 4px; } + th.bltr { border-left: 1px solid black; + border-top: 1px solid black; + border-right: 1px solid black; } + th.btrb { border-bottom: 1px solid black; + border-top: 1px solid black; + border-right: 1px solid black; } + th.btlbr { border-left: 1px solid black; + border-top: 1px solid black; + border-right: 1px solid black; + border-bottom: 1px solid black; } + th.brb { border-right: 1px solid black; + border-bottom: 1px solid black; } + th.brbl { border-left: 1px solid black; + border-bottom: 1px solid black; + border-right: 1px solid black; } + td.right { text-align: right; vertical-align: top; } + td.center { text-align: center; vertical-align: top; } + td.br { vertical-align: top; + border-right: 1px solid black; } + td.bl { vertical-align: top; + border-left: 1px solid black; } + td.brb { vertical-align: top; + border-right: 1px solid black; + border-bottom: 1px solid black; } + td.blr { vertical-align: top; + border-left: 1px solid black; + border-right: 1px solid black; } + td.blbr { vertical-align: top; + border-left: 1px solid black; + border-right: 1px solid black; + border-bottom: 1px solid black; } + td.center_br { text-align: center; + border-right: 1px solid black; } + td.center_brb { text-align: center; + border-right: 1px solid black; + border-bottom: 1px solid black; } + td.right_br { text-align: right; + border-right: 1px solid black; } + td.right_bl { text-align: right; + border-left: 1px solid black; } + td.right_bb { text-align: right; + border-bottom: 1px solid black; } + td.right_brl { text-align: right; + border-left: 1px solid black; + border-right: 1px solid black; } + td.right_brb { text-align: right; + border-bottom: 1px solid black; + border-right: 1px solid black; } + td.right_blb { text-align: right; + border-left: 1px solid black; + border-bottom: 1px solid black; } + td.right_brbl { text-align: right; + border-right: 1px solid black; + border-bottom: 1px solid black; + border-left: 1px solid black; } + span.page { position: absolute; left: 90%; right: auto; + text-align: right; text-indent: 0em; + color: gray; font-size: 9pt; font-weight: normal; } + + </style> +</head> + +<body> + + +<pre> + +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: UTF-8 + +*** START OF THIS PROJECT GUTENBERG EBOOK RECREATIONS IN ASTRONOMY *** + + + + +Produced by Robert J. Hall. + + + + + +</pre> + + +<div style="width: 100%; text-align: center;"> +<span style="margin: 8px; width: 501px; + font-size: smaller; text-align: justify; "> +<a name="page_ii"><span class="page">Page ii</span></a> +<img src="images/front.jpg" width="501" height="825" alt="frontispiece"> +<br /> +THE CONSTELLATIONS OF ORION AND TAURUS. <br /> +NOTES.—Star α in Taurus is red, has eight metals; moves +east (<a href="#page_227">page 227</a>). At <tt>o</tt> above tip of +right horn is the Crab Nebula (<a href="#page_219">page 219</a>). In +Orion, α is variable, has five metals; recedes 22 miles per +second. β, δ, ε, ξ, ρ, etc., are double +stars, the component parts of various colors and magnitudes (<a +href="#page_212">page 212</a>, note). λ and ι are triple; +σ, octuple; θ, multiple, surrounded by a fine Nebula +(<a href="#page_218">page 218</a>). +</span> +</div> + +<h1> +<a name="page_iii"><span class="page">Page iii</span></a> +RECREATIONS IN ASTRONOMY</h1> + +<p class="center"> +WITH +</p> + +<p class="subtitle"> +<i>DIRECTIONS FOR PRACTICAL EXPERIMENTS AND TELESCOPIC WORK</i> +</p> + +<p class="center"> +BY +</p> + +<p class="author"> +HENRY WHITE WARREN, D.D. +</p> + +<p class="center"> +AUTHOR OF "SIGHTS AND INSIGHTS; OR, KNOWLEDGE BY TRAVEL," ETC. +</p> + +<p class="center"> +WITH EIGHTY-THREE ILLUSTRATIONS AND MAPS OF STARS +</p> + +<table border="1" cellspacing="0" cellpadding="40" class="center"> +<tr><td class="center"> +<a name="page_v"><span class="page">Page v</span></a> +ΤΗΙ ΨΥΧΗΙ<br /> +ΤΗΙ ΑΓΑΠΗΤΗΙ<br /> +ΑΣΤΡΑΠΤΟΥΣΗΙ +<br /> +ΚΑΙ<br /> +ΙΣΑΓΓΕΔΩΙ +</td></tr> +</table> + +<h2> +<a name="page_vii"><span class="page">Page vii</span></a> +PREFACE.</h2> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +While nearly all men are prevented from practical experimentation +in these high realms of knowledge, few +<a name="page_viii"><span class="page">Page viii</span></a> +have so little leisure as to be debarred from intelligently enjoying +the results of the investigations of others. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_ix"><span class="page">Page ix</span></a> +CONTENTS.</h2> + +<table border="0"> +<tr> + <td class="right">CHAP.</td> + <td> </td> +</tr> + +<tr> + <td class="right">I.</td> + <td><a href="#page_1">CREATIVE PROCESSES</a></td> +</tr> + +<tr> + <td class="right">II.</td> + <td><a href="#page_15">CREATIVE PROGRESS</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_24">Constitution of Light</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_28">Chemistry of Suns revealed + by Light</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_30">Creative Force of Light</a></td> +</tr> + +<tr> + <td class="right">III.</td> + <td><a href="#page_41">ASTRONOMICAL INSTRUMENTS</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_43">The Telescope</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_44">The Reflecting Telescope</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_46">The Spectroscope</a></td> +</tr> + +<tr> + <td class="right">IV.</td> + <td><a href="#page_55">CELESTIAL MEASUREMENTS</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_58">Celestial Movements</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_60">How to Measure</a></td> +</tr> + +<tr> + <td class="right">V.</td> + <td><a href="#page_75">THE SUN</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_94">What the Sun does for + us</a></td> +</tr> + +<tr> + <td class="right">VI.</td> + <td><a href="#page_97">THE PLANETS, AS SEEN FROM SPACE</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_108">The Outlook from the + Earth</a></td> +</tr> + +<tr> + <td class="right">VII.</td> + <td><a href="#page_117">SHOOTING-STARS, METEORS, AND COMETS</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_122">Aerolites</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_126">Comets</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_128">Famous Comets</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_131">Of what do Comets + consist?</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_133">Will Comets strike the + Earth?</a></td> +</tr> + +<tr> + <td class="right">VIII.</td> + <td><a href="#page_135">THE PLANETS AS INDIVIDUALS</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_138">Vulcan</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_138">Mercury</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_139">Venus</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_141">The Earth</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_143">The Aurora Borealis</a></td> +</tr><tr> + <td> </td> + <td class="inset"> +<a name="page_x"><span class="page">Page x</span></a> + <a href="#page_144">The Delicate Balance of + Forces</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_146">Tides</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_151">The Moon</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_155">Telescopic Appearance</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_157">Eclipses</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_159">Mars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_161">Satellites of Mars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_162">Asteroids</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_164">Jupiter</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_165">Satellites of Jupiter</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_167">Saturn</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_169">Rings of Saturn</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_172">Satellites of Saturn</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_173">Uranus</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_175">Neptune</a></td> +</tr> + +<tr> + <td class="right">IX.</td> + <td><a href="#page_179">THE NEBULAR HYPOTHESIS</a></td> +</tr> + +<tr> + <td class="right">X.</td> + <td><a href="#page_193">THE STELLAR SYSTEM</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_195">The Open Page of the + Heavens</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_202">Equatorial Constellations</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_209">Characteristics of the + Stars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_210">Number</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_210">Double and Multiple + Stars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_214">Colored Stars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_215">Clusters of Stars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_217">Nebulæ</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_220">Variable Stars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_223">Temporary, New, and Lost + Stars</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_226">Movements of Stars</a></td> +</tr> + +<tr> + <td class="right">XI.</td> + <td><a href="#page_229">THE WORLDS AND THE WORD</a></td> +</tr> + +<tr> + <td class="right">XII.</td> + <td><a href="#page_247">THE ULTIMATE FORCE</a></td> +</tr> + +<tr> + <td colspan="2"><a href="#page_269">SUMMARY OF LATEST DISCOVERIES + AND CONCLUSIONS</a></td> +</tr> + +<tr> + <td colspan="2"><a href="#page_274">SOME ELEMENTS OF THE SOLAR + SYSTEM</a></td> +</tr> + +<tr> + <td colspan="2"><a href="#page_275">EXPLANATION OF ASTRONOMICAL + SYMBOLS</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_275">Signs of the Zodiac</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_275">Other Abbreviations Used in + the Almanac</a></td> +</tr><tr> + <td> </td> + <td class="inset"><a href="#page_275">Greek Alphabet Used Indicating + the Stars</a></td> +</tr> + +<tr> + <td colspan="2"><a href="#page_276">CHAUTAUQUA OUTLINE FOR + STUDENTS</a></td> +</tr> + +<tr> + <td colspan="2"><a href="#page_279">GLOSSARY OF ASTRONOMICAL + TERMS AND INDEX</a></td> +</tr> +</table> + +<h2> +<a name="page_xi"><span class="page">Page xi</span></a> +ILLUSTRATIONS</h2> + +<table border="0"> +<tr> + <td class="right">FIG.</td> + <td> </td> +</tr> + +<tr> + <td class="right"> </td> + <td><a href="#page_ii">The Constellations of Orion and + Taurus</a></td> +</tr> + +<tr> + <td class="right">1.</td> + <td><a href="#page_8">An Orbit resulting from Attraction and + Projection</a></td> +</tr> + +<tr> + <td class="right">2.</td> + <td><a href="#page_10">The Moon's Orbit about the Earth</a></td> +</tr> + +<tr> + <td class="right">3.</td> + <td><a href="#page_11">Changes of Orbit by Mutual + Attraction</a></td> +</tr> + +<tr> + <td class="right">4.</td> + <td><a href="#page_22">Velocity of Light measured by Jupiter's + Satellites</a></td> +</tr> + +<tr> + <td class="right">5.</td> + <td><a href="#page_23">Velocity of Light measured by Fizeau's + Toothed Wheel</a></td> +</tr> + +<tr> + <td class="right">6.</td> + <td><a href="#page_25">White Light resolved into Colors</a></td> +</tr> + +<tr> + <td class="right">7.</td> + <td><a href="#page_37">Showing amount of Light received by + Different Planets</a></td> +</tr> + +<tr> + <td class="right">8.</td> + <td><a href="#page_37">Measuring Intensities of Lights</a></td> +</tr> + +<tr> + <td class="right">9.</td> + <td><a href="#page_38">Reflection and Diffusion of + Light</a></td> +</tr> + +<tr> + <td class="right">10.</td> + <td><a href="#page_39">Manifold Reflections</a></td> +</tr> + +<tr> + <td class="right">11.</td> + <td><a href="#page_40">Refraction by Water</a></td> +</tr> + +<tr> + <td class="right">12.</td> + <td><a href="#page_40">Atmospherical Reflection</a></td> +</tr> + +<tr> + <td class="right">13.</td> + <td><a href="#page_43">Refracting Telescope</a></td> +</tr> + +<tr> + <td class="right">14.</td> + <td><a href="#page_44">Reflecting Telescope</a></td> +</tr> + +<tr> + <td class="right">15.</td> + <td><a href="#page_46">The Cambridge Equatorial Refractor</a></td> +</tr> + +<tr> + <td class="right">16.</td> + <td><a href="#page_47">The new Reflecting Telescope at + Paris</a></td> +</tr> + +<tr> + <td class="right">17.</td> + <td><a href="#page_49">Spectroscope, with Battery of + Prisms</a></td> +</tr> + +<tr> + <td class="right">18.</td> + <td><a href="#page_50">Spectra of Glowing Hydrogen and of the + Sun</a></td> +</tr> + +<tr> + <td class="right">19.</td> + <td><a href="#page_59">Illustrating Arcs and Angles</a></td> +</tr> + +<tr> + <td class="right">20.</td> + <td><a href="#page_59">Measuring Objects by observing + Angles</a></td> +</tr> + +<tr> + <td class="right">21.</td> + <td><a href="#page_61">Mural Circle</a></td> +</tr> + +<tr> + <td class="right">22.</td> + <td><a href="#page_63">Scale to measure Hundredths of an + Inch</a></td> +</tr> + +<tr> + <td class="right">23.</td> + <td><a href="#page_63">Spider-lines to determine Star + Transits</a></td> +</tr> + +<tr> + <td class="right">24.</td> + <td> +<a name="page_xii"><span class="page">Page xii</span></a> + <a href="#page_66">Illustrating Triangulation</a></td> +</tr> + +<tr> + <td class="right">25.</td> + <td><a href="#page_67">Measuring Distance to an Inaccessible + Object</a></td> +</tr> + +<tr> + <td class="right">26.</td> + <td><a href="#page_67">Measuring Elevation of an Inaccessible + Object</a></td> +</tr> + +<tr> + <td class="right">27.</td> + <td><a href="#page_69">Illustrating Parallax</a></td> +</tr> + +<tr> + <td class="right">28.</td> + <td><a href="#page_71">Illustrating Stellar Parallax</a></td> +</tr> + +<tr> + <td class="right">29.</td> + <td><a href="#page_72">Mode of Ascertaining Longitude</a></td> +</tr> + +<tr> + <td class="right">30.</td> + <td><a href="#page_79">Relative Size of Sun, as seen from + Different Planets</a></td> +</tr> + +<tr> + <td class="right">31.</td> + <td><a href="#page_80">Zodiacal Light</a></td> +</tr> + +<tr> + <td class="right">32.</td> + <td><a href="#page_82">Corona of the Sun in 1858—Brazil</a></td> +</tr> + +<tr> + <td class="right">33.</td> + <td><a href="#page_83">Corona of the Sun in 1878—Colorado</a></td> +</tr> + +<tr> + <td class="right">34.</td> + <td><a href="#page_85">Solar Prominences of Flaming Hydrogen</a></td> +</tr> + +<tr> + <td class="right">35.</td> + <td><a href="#page_90">Changes in Solar Cavities during + Rotation</a></td> +</tr> + +<tr> + <td class="right">36.</td> + <td><a href="#page_92">Solar Spot</a></td> +</tr> + +<tr> + <td class="right">37.</td> + <td><a href="#page_96">Holding Telescope to see the Sun-spots</a></td> +</tr> + +<tr> + <td class="right">38.</td> + <td><a href="#page_100">Orbits and Comparative Sizes of the + Planets</a></td> +</tr> + +<tr> + <td class="right">39.</td> + <td><a href="#page_103">Orbit of Earth, illustrating + Seasons</a></td> +</tr> + +<tr> + <td class="right">40.</td> + <td><a href="#page_107">Inclination of Planes of Planetary + Orbits</a></td> +</tr> + +<tr> + <td class="right">41.</td> + <td><a href="#page_107">Inclination of Orbits of Earth and + Venus</a></td> +</tr> + +<tr> + <td class="right">42.</td> + <td><a href="#page_110">Showing the Sun's Movement among the Stars</a></td> +</tr> + +<tr> + <td class="right">43.</td> + <td><a href="#page_111">Passage of the Sun by Star Regulus</a></td> +</tr> + +<tr> + <td class="right">44.</td> + <td><a href="#page_112">Apparent Path of Jupiter among the + Stars</a></td> +</tr> + +<tr> + <td class="right">45.</td> + <td><a href="#page_112">Illustrating Position of Planets</a></td> +</tr> + +<tr> + <td class="right">46.</td> + <td><a href="#page_113">Apparent Movements of an Inferior + Planet</a></td> +</tr> + +<tr> + <td class="right">47.</td> + <td><a href="#page_114">Apparent Movements of a Superior + Planet</a></td> +</tr> + +<tr> + <td class="right">47<i>a</i>.</td> + <td><a href="#page_118">A Swarm of Meteors meeting the + Earth</a></td> +</tr> + +<tr> + <td class="right">48.</td> + <td><a href="#page_120">Explosion of a Bolide</a></td> +</tr> + +<tr> + <td class="right">49.</td> + <td><a href="#page_121">Flight of Bolides</a></td> +</tr> + +<tr> + <td class="right">50.</td> + <td><a href="#page_122">The Santa Rosa Aerolite</a></td> +</tr> + +<tr> + <td class="right">51.</td> + <td><a href="#page_125">Orbit of November Meteors and the Comet + of 1866</a></td> +</tr> + +<tr> + <td class="right">52.</td> + <td><a href="#page_127">Aspects of Remarkable Comets</a></td> +</tr> + +<tr> + <td class="right">53.</td> + <td><a href="#page_140">Phases and Apparent Dimensions of + Venus</a></td> +</tr> + +<tr> + <td class="right">54.</td> + <td><a href="#page_142">The Earth and Moon in Space</a></td> +</tr> + +<tr> + <td class="right">55.</td> + <td><a href="#page_143">Aurora as Waving Curtains</a></td> +</tr> + +<tr> + <td class="right">56.</td> + <td><a href="#page_147">Tide resulting from Centrifugal + Motion</a></td> +</tr> + +<tr> + <td class="right">57.</td> + <td><a href="#page_150">Lunar Landscape</a></td> +</tr> + +<tr> + <td class="right">58.</td> + <td> +<a name="page_xiii"><span class="page">Page xiii</span></a> + <a href="#page_154">Telescopic View of the Moon</a></td> +</tr> + +<tr> + <td class="right">59.</td> + <td><a href="#page_155">Illumination of Lunar Craters and + Peaks</a></td> +</tr> + +<tr> + <td class="right">60.</td> + <td><a href="#page_156">Lunar Crater "Copernicus"</a></td> +</tr> + +<tr> + <td class="right">61.</td> + <td><a href="#page_157">Eclipses: Shadows of Earth and Moon</a></td> +</tr> + +<tr> + <td class="right">62.</td> + <td><a href="#page_160">Apparent Sizes of Mars, seen from the + Earth</a></td> +</tr> + +<tr> + <td class="right">63.</td> + <td><a href="#page_164">Jupiter</a></td> +</tr> + +<tr> + <td class="right">64.</td> + <td><a href="#page_166">Various Positions of Jupiter's + Satellites</a></td> +</tr> + +<tr> + <td class="right">65.</td> + <td><a href="#page_168">View of Saturn and his Rings</a></td> +</tr> + +<tr> + <td class="right">66.</td> + <td><a href="#page_176">Perturbations of Uranus</a></td> +</tr> + +<tr> + <td class="right">67.</td> + <td><a href="#page_201">Map: Circumpolar Constellations</a></td> +</tr> + +<tr> + <td class="right">68.</td> + <td><a href="#page_202">Map of Constellations on the Meridian in + December</a></td> +</tr> + +<tr> + <td class="right">69.</td> + <td><a href="#page_203">Map of Constellations on the Meridian in + January</a></td> +</tr> + +<tr> + <td class="right">70.</td> + <td><a href="#page_204">Map of Constellations on the Meridian in + April</a></td> +</tr> + +<tr> + <td class="right">71.</td> + <td><a href="#page_205">Map of Constellations on the Meridian in + June</a></td> +</tr> + +<tr> + <td class="right">72.</td> + <td><a href="#page_206">Map of Constellations on the Meridian in + September</a></td> +</tr> + +<tr> + <td class="right">73.</td> + <td><a href="#page_207">Map of Constellations on the Meridian in + November</a></td> +</tr> + +<tr> + <td class="right">74.</td> + <td><a href="#page_208">Southern Circumpolar Constellations</a></td> +</tr> + +<tr> + <td class="right">75.</td> + <td><a href="#page_213">Aspects of Double Stars</a></td> +</tr> + +<tr> + <td class="right">76.</td> + <td><a href="#page_216">Sprayed Star Cluster below η in + Hercules</a></td> +</tr> + +<tr> + <td class="right">77.</td> + <td><a href="#page_216">Globular Star Cluster in the Centaur</a></td> +</tr> + +<tr> + <td class="right">78.</td> + <td><a href="#page_218">Great Nebula about θ Orionis</a></td> +</tr> + +<tr> + <td class="right">79.</td> + <td><a href="#page_219">The Crab Nebula above ζ Tauri</a></td> +</tr> + +<tr> + <td class="right">80.</td> + <td><a href="#page_220">The Ring Nebula in Lyra</a></td> +</tr> + +<tr> + <td class="right">81.</td> + <td><a href="#page_221">Showing Place of Ring Nebula</a></td> +</tr> + +<tr> + <td class="right">82.</td> + <td><a href="#page_272">The Horizontal Pendulum</a></td> +</tr> + +<tr> + <td colspan="2"> </td> +</tr> + +<tr> + <td colspan="2"><a href="#page_52">COLORED PLATE REPRESENTING + VARIOUS SPECTA</a></td> +</tr> + +<tr> + <td colspan="2"><a href="#page_285">MAPS TO FIND THE STARS</a></td> +</tr> +</table> + +<h2> +<a name="page_1"><span class="page">Page 1</span></a> +I.</h2> + +<p class="subtitle"> +CREATIVE PROCESSES. +</p> + +<p class="bquote"> +"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."—<i>Genesis</i> i. 1, 2. +</p> + +<p class="bquote"> +<a name="page_2"><span class="page">Page 2</span></a> +"Not to the domes, where crumbling arch and column<br> + Attest the feebleness of mortal hand,<br> +But to that fane, most catholic and solemn,<br> + Which God hath planned,—<br> +To that cathedral, boundless as our wonder,<br> + Whose quenchless lamps the sun and stars supply;<br> +Its choir the winds and waves, its organ thunder,<br> + Its dome the sky." H. W. LONGFELLOW. +</p> + +<p class="bquote"> +"The heavens are a point from the pen of His perfection;<br> +The world is a rose-bud from the bower of His beauty;<br> +The sun is a spark from the light of His wisdom;<br> +And the sky a bubble on the sea of His power."<br> + SIR W. JONES. +</p> + +<p class="title"> +<a name="page_3"><span class="page">Page 3</span></a> +RECREATIONS IN ASTRONOMY. +</p> + +<hr> + +<p class="title">I.</p> + +<p class="subtitle"> +<i>CREATIVE PROCESSES.</i> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +This dial not only shows present movements, but it keeps the history +of uncounted ages past ready to be +<a name="page_4"><span class="page">Page 4</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_5"><span class="page">Page 5</span></a> +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 +</p> + +<p class="bquote"> +"The poet's eye, in a fine frenzy rolling,<br> +Doth glance from heaven to earth, from earth to heaven;<br> +And, as imagination bodies forth<br> +The forms of things unknown, the poet's pen<br> +Turns them to shapes, and gives to airy nothing<br> +A local habitation and a name." +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_6"><span class="page">Page 6</span></a> +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, <i>Gravity is proportioned to the quantity +of matter</i>; and 2, <i>The force of gravity varies inversely +as the square of the distance from the centre of the attracting +body</i>. +</p> + +<p class="indent"> +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 +<a name="page_7"><span class="page">Page 7</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_8"><span class="page">Page 8</span></a> +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. +</p> + +<p class="indent"> +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? +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 420px; + font-size: smaller; text-align: justify; "> +<img src="images/fig01.jpg" width="420" height="170" alt="Figure 1"> +<br /> +Fig. 1.—Orbit A D, resulting from attraction, A C, and projectile +force, A B. +</span> +</div> + +<p class="indent"> +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 +<a name="page_9"><span class="page">Page 9</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<a name="page_10"><span class="page">Page 10</span></a> +<img src="images/fig02.jpg" width="142" height="207" alt="Figure 2"> +<br /> +Fig. 2. +</span> +</span> + +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 +<a name="page_11"><span class="page">Page 11</span></a> +of our night-wandering orb has just been explained by Professor +Hansen, of Gotha, as a curious result of the attraction of Venus. +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig03.jpg" width="196" height="190" alt="Figure 3"> +<br /> +Fig. 3.—Changes of orbit by mutual attraction. +</span> +</span> + +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. +</p> + +<p class="indent"> +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 +<a name="page_12"><span class="page">Page 12</span></a> +Saturn; and they will be near again, be drawn together, hastened, +and retarded, as before; their next conjunction would be at 3, +3, etc. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +The difficulties would be greatly increased if the orbits +<a name="page_13"><span class="page">Page 13</span></a> +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. <i>They are guided by an intelligent mind and +an almighty arm.</i> +</p> + +<p class="indent"> +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, +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_14"><span class="page">Page 14</span></a> +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." +</p> + +<h2> +<a name="page_15"><span class="page">Page 15</span></a> +II.</h2> + +<p class="subtitle"> +CREATIVE PROGRESS. +</p> + +<p class="bquote"> +"And God said, Let there be light, and there was +light."—<i>Genesis</i> i., 3. +</p> + +<p class="bquote"> +"God is light."—1 <i>John</i>, i. 5. +</p> + +<p class="bquote"> +<a name="page_16"><span class="page">Page 16</span></a> +"Hail! holy light, offspring of Heaven first born,<br> +Or of the eternal, co-eternal beam,<br> +May I express thee unblamed? since God is light,<br> +And never but in unapproached light<br> +Dwelt from eternity, dwelt then in thee,<br> +Bright effluence of bright essence increate."<br> + MILTON. +</p> + +<p class="bquote"> +"A million torches lighted by Thy hand<br> +Wander unwearied through the blue abyss:<br> +They own Thy power, accomplish Thy command,<br> +All gay with life, all eloquent with bliss.<br> +What shall we call them? Piles of crystal light—<br> +A glorious company of golden streams—<br> +Lamps of celestial ether burning bright—<br> +Suns lighting systems with their joyous beams?<br> +But 'Thou to these art as the noon to night."<br> + DERZHAVIN, trans. by BOWRING. +</p> + +<p class="title"> +<a name="page_17"><span class="page">Page 17</span></a> +II.</p> + +<p class="subtitle"> +<i>CREATIVE PROGRESS.</i> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 has bones, +<a name="page_18"><span class="page">Page 18</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_19"><span class="page">Page 19</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_20"><span class="page">Page 20</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_21"><span class="page">Page 21</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 aërial sprite that carries our +measuring-rods across the infinite +<a name="page_22"><span class="page">Page 22</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 413px; + font-size: smaller; text-align: justify; "> +<img src="images/fig04.jpg" width="413" height="220" alt="Figure 4"> +<br /> +Fig. 4.—Velocity of Light measured by Eclipses of Jupiter's +Moons. +</span> +</div> + +<p class="indent"> +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 +<a name="page_23"><span class="page">Page 23</span></a> +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 + +<span style="float: left; width: 274px; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig05.jpg" width="274" height="253" alt="Figure 5"> +<br /> +Fig. 5.—Measuring the Velocity of Light. +</span> +</span> + +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. +</p> + +<p class="indent"> +When we take instantaneous photographs by the exposure +<a name="page_24"><span class="page">Page 24</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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." +</p> + +<h3><i>Constitution of Light.</i></h3> + +<p class="indent"> +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 +<a name="page_25"><span class="page">Page 25</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig06.jpg" width="406" height="296" alt="Figure 6"> +<br /> +Fig. 6.—White Light resolved into Colors. +</span> +</span> + +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 vibrations +<a name="page_26"><span class="page">Page 26</span></a> +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, +</p> + +<p class="bquote"> +"Freedom mingles with its gorgeous dyes<br> +The milky baldrick of the skies,<br> +And stripes its pore celestial white<br> +With streakings of the morning light." +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_27"><span class="page">Page 27</span></a> +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— +</p> + +<p class="bquote"> +"There's not the smallest orb which thou beholdest,<br> +But in his motion like an angel sings,<br> +Still quiring to the young-eyed cherubim.<br> +Such harmony is in immortal souls;<br> +But, whilst this muddy vesture of decay<br> +Doth grossly close it in, we cannot hear it." +</p> + +<p class="indent"> +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: +</p> + +<p class="bquote"> +"In reason's ear they all rejoice,<br> +And utter forth a glorious voice.<br> +Forever singing, as they shine,<br> +The hand that made us is divine." +</p> + +<p class="indent"> +This music is not monotonous. Stars draw near each other, and make +a light that is unapproachable by mortals; +<a name="page_28"><span class="page">Page 28</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Chemistry of Suns revealed by Light.</i></h3> + +<p class="indent"> +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 they +<a name="page_29"><span class="page">Page 29</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_30"><span class="page">Page 30</span></a> +the stars whose very substance we know! If we were transported +thither, or beyond, we should not be altogether strangers in an +unknown realm. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Creative Force of Light.</i></h3> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_31"><span class="page">Page 31</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_32"><span class="page">Page 32</span></a> +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. +</p> + +<p class="indent"> +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, +<a name="page_33"><span class="page">Page 33</span></a> +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." +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +The heat of the sun beam goes through glass without +<a name="page_34"><span class="page">Page 34</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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: +</p> + +<p class="bquote"> +"Who there inhabit must have other powers,<br> +Juices, and veins, and sense and life than ours;<br> +One moment's cold like theirs would pierce the bone,<br> +Freeze the heart's-blood, and turn us all to stone." +</p> + +<p class="indent"> +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 +<a name="page_35"><span class="page">Page 35</span></a> +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 aërial 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. +</p> + +<p class="indent"> +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, +<a name="page_36"><span class="page">Page 36</span></a> +"Bloom again;" and the snows melt, the ice retires, and vegetation +breaks forth, birds sing, and spring is about us. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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." +</p> + +<p class="center"> +<a name="page_37"><span class="page">Page 37</span></a> +EXPERIMENTS WITH LIGHT. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 422px; + font-size: smaller; text-align: justify; "> +<img src="images/fig07.jpg" width="422" height="152" alt="Figure 7"> +<br /> +Fig. 7. +</span> +</div> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 423px; + font-size: smaller; text-align: justify; "> +<img src="images/fig08.jpg" width="423" height="191" alt="Figure 8"> +<br /> +Fig. 8.—Measuring Intensities of Light. +</span> +</div> + +<p class="indent"> +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 +<a name="page_38"><span class="page">Page 38</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 464px; + font-size: smaller; text-align: justify; "> +<img src="images/fig09.jpg" width="464" height="437" alt="Figure 9"> +<br /> +Fig. 9.—Reflection and Diffusion of Light. +</span> +</div> + +<p class="indent"> +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, +it becomes +<a name="page_39"><span class="page">Page 39</span></a> +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. +</p> + +<p class="indent"> +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? +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 422px; + font-size: smaller; text-align: justify; "> +<img src="images/fig10.jpg" width="422" height="186" alt="Figure 10"> +<br /> +Fig. 10.—Manifold Reflections. +</span> +</div> + +<p class="indent"> +In Fig. 10 the sunbeam enters at A, and, striking the mirror <i>m</i> +at <i>a</i>, 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 <i>b</i>, 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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<table style="float: left; margin: 4px; width: 224px;"> +<tr><td class="center"> +<span style="font-size: smaller;"> +<img src="images/fig11.jpg" width="224" height="84" alt="Figure 11"> +<br /> +Fig. 11. +</span> +</td></tr> +</table> + +<p class="indent"> +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 appear +<a name="page_40"><span class="page">Page 40</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 498px; + font-size: smaller; text-align: justify; "> +<img src="images/fig12.jpg" width="498" height="183" alt="Figure 12"> +<br /> +Fig. 12.—Atmospherical Refraction. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="center"> +DECOMPOSITION OF LIGHT. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_41"><span class="page">Page 41</span></a> +III.</h2> + +<p class="subtitle"> +ASTRONOMICAL INSTRUMENTS. +</p> + +<p class="bquote"> +"The eyes of the Lord are in every place."—<i>Proverbs</i> xv. 3. +</p> + +<p class="indent"> +<a name="page_42"><span class="page">Page 42</span></a> +"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. +</p> + +<p class="title"> +<a name="page_43"><span class="page">Page 43</span></a> +III. +</p> + +<p class="subtitle"><i>THE TELESCOPE.</i></p> + +<p class="indent"> +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 +<a name="page_44"><span class="page">Page 44</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 451px; + font-size: smaller; text-align: justify; "> +<img src="images/fig13.jpg" width="451" height="88" alt="Figure 13"> +<br /> +Fig. 13.—Refracting Telescope. +</span> +</div> + +<p class="indent"> +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. +</p> + +<h3><i>The Reflecting Telescope</i>.</h3> + +<p class="indent"> +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 +<a name="page_45"><span class="page">Page 45</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 451px; + font-size: smaller; text-align: justify; "> +<img src="images/fig14.jpg" width="517" height="108" alt="Figure 14"> +<br /> +Fig. 14.—Reflecting Telescope. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_46"><span class="page">Page 46</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 442px; + font-size: smaller; text-align: justify; "> +<img src="images/fig15.jpg" width="442" height="567" alt="Figure 15"> +<br /> +Fig. 15.—Cambridge Equatorial. +</span> +</div> + +<h3><i>The Spectroscope.</i></h3> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<a name="page_47"><span class="page">Page 47</span></a> +<img src="images/fig16.jpg" width="548" height="903" alt="Figure 16"> +<br /> +Fig. 16.—New Paris Reflector. +</span> +</span> + +<a name="page_49"><span class="page">Page 49</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig17.jpg" width="301" height="375" alt="Figure 17"> +<br /> +Fig. 17.—Spectroscope, with Battery of Prisms. +</span> +</span> + +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 +<a name="page_50"><span class="page">Page 50</span></a> +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. +</p> + +<p class="indent"> +Attached to the examining telescope is a diamond-ruled scale of glass, +enabling us to fix the position of any line with great exactness. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 355px; + font-size: smaller; text-align: justify; "> +<img src="images/fig18.jpg" width="355" height="123" alt="Figure 18"> +<br /> +Fig. 18.—Spectra of glowing Hydrogen and the Sun. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +<a name="page_51"><span class="page">Page 51</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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? +</p> + +<p class="indent"> +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 +<a name="page_52"><span class="page">Page 52</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 540px; + font-size: smaller; text-align: justify; "> +<a href="images/spectra.jpg"><br> +<img src="images/spectra_small.jpg" width="540" height="377" + alt="spectra"></a> +</span> +</div> + +<table border="0" class="center"> +<tr> + <td>1. Solar Spectrum.</td> + <td>3. Spectrum of Sodium.</td> + <td>5. Spectrum of Calcium.</td> +</tr><tr> + <td>2. Spectrum of Potassium.</td> + <td>4. Spectrum of Strontium.</td> + <td>6. Spectrum of Barium.</td> +</tr> +</table> + +<p class="indent"> +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 the +<a name="page_53"><span class="page">Page 53</span></a> +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. +</p> + +<p class="indent"> +It should be recognized that Professor Young, of +<a name="page_54"><span class="page">Page 54</span></a> +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. +</p> + +<p class="indent"> +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 nebulæ. 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. +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_55"><span class="page">Page 55</span></a> +IV.</h2> + +<p class="subtitle"> +CELESTIAL MEASUREMENTS. +</p> + +<p class="bquote"> +"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."—<i>Isa.</i> +xl. 12; xlviii. 13. +</p> + +<p class="bquote"> +<a name="page_56"><span class="page">Page 56</span></a> +"Go to yon tower, where busy science plies<br> +Her vast antennæ, feeling thro' the skies;<br> +That little vernier, on whose slender lines<br> +The midnight taper trembles as it shines,<br> +A silent index, tracks the planets' march<br> +In all their wanderings thro' the ethereal arch,<br> +Tells through the mist where dazzled Mercury burns,<br> +And marks the spot where Uranus returns. +</p> + +<p class="bquote"> +"So, till by wrong or negligence effaced,<br> +The living index which thy Maker traced<br> +Repeats the line each starry virtue draws<br> +Through the wide circuit of creation's laws;<br> +Still tracks unchanged the everlasting ray<br> +Where the dark shadows of temptation stray;<br> +But, once defaced, forgets the orbs of light,<br> +And leaves thee wandering o'er the expanse of night."<br> + OLIVER WENDELL HOLMES. +</p> + +<p class="title"> +<a name="page_57"><span class="page">Page 57</span></a> +IV. +</p> + +<p class="subtitle"> +<i>CELESTIAL MEASUREMENTS.</i> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +In 1878 the United States steam-ship <i>Enterprise</i> 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. +</p> + +<p class="indent"> +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 +<a name="page_58"><span class="page">Page 58</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Celestial Movements.</i></h3> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_59"><span class="page">Page 59</span></a> +one (Fig. 19). Draw through it a diameter horizontally, another + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig19.jpg" width="129" height="131" alt="Figure 19"> +<br /> +Fig. 19. +</span> +</span> + +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 "). +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 398px; + font-size: smaller; text-align: justify; "> +<img src="images/fig20.jpg" width="398" height="113" alt="Figure 20"> +<br /> +Fig. 20.—Illustration of Angles. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +If this star-sprent sphere were made to revolve once in twenty-four +hours, all the stars would successively +<a name="page_60"><span class="page">Page 60</span></a> +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. +</p> + +<p class="indent"> +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, +</p> + +<p class="bquote"> +"Of whose true-fixed and resting quality<br> +There is no fellow in the firmament." +</p> + +<h3><i>How to Measure.</i></h3> + +<p class="indent"> +Suppose a telescope, fixed to a mural circle, to revolve on an axis, +as in Fig. 21; point it horizontally at a star; +<a name="page_61"><span class="page">Page 61</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 329px; + font-size: smaller; text-align: justify; "> +<img src="images/fig21.jpg" width="329" height="330" alt="Figure 21"> +<br /> +Fig. 21.—Mural Circle. +</span> +</div> + +<p class="indent"> +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 +<a name="page_62"><span class="page">Page 62</span></a> +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. +</p> + +<p class="indent"> +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 +mountain +<a name="page_63"><span class="page">Page 63</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig22.jpg" width="142" height="144" alt="Figure 22"> +<br /> +Fig. 22. +</span> +</span> + +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. +</p> + +<p class="indent"> +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 +<a name="page_64"><span class="page">Page 64</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_65"><span class="page">Page 65</span></a> +the star will come into the field just above the horizontal thread. + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig23.jpg" width="242" height="245" alt="Figure 23"> +<br /> +Fig. 23.—Transit of a Star noted. +</span> +</span> + +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. +</p> + +<p class="indent"> +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 +<a name="page_66"><span class="page">Page 66</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<table style="float: right; margin: 4px; width: 140px;"> +<tr><td class="center"> +<span style="font-size: smaller;"> +<img src="images/fig24.jpg" width="140" height="132" alt="Figure 24"> +<br /> +Fig. 24. +</span> +</td></tr> +</table> + +<table style="float: left; margin: 4px; width: 153px;"> +<tr><td class="center"> +<span style="font-size: smaller;"> +<img src="images/fig25.jpg" width="153" height="355" alt="Figure 25"> +<br /> +Fig. 25.—Measuring Distances. +</span> +</td></tr> +</table> + +<p class="indent"> +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 +<a name="page_67"><span class="page">Page 67</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_68"><span class="page">Page 68</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 502px; + font-size: smaller; text-align: justify; "> +<img src="images/fig26.jpg" width="502" height="115" alt="Figure 26"> +<br /> +Fig. 26.—Measuring Elevations. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_69"><span class="page">Page 69</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig27.jpg" width="194" height="322" alt="Figure 27"> +<br /> +Fig. 27. +</span> +</span> + +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. +</p> + +<p class="indent"> +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 +<a name="page_70"><span class="page">Page 70</span></a> +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 +<a name="page_71"><span class="page">Page 71</span></a> +earth's orbit on one side, as T R A (Fig. 28), and a line were + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig28.jpg" width="279" height="95" alt="Figure 28"> +<br /> +Fig. 28. +</span> +</span> + +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. +</p> + +<p class="indent"> +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 +<a name="page_72"><span class="page">Page 72</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 512px; + font-size: smaller; text-align: justify; "> +<img src="images/fig29.jpg" width="512" height="75" alt="Figure 29"> +<br /> +Fig. 29.—Mode of Ascertaining Longitude. +</span> +</div> + +<p class="indent"> +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 +<a name="page_73"><span class="page">Page 73</span></a> +Centauri, seven and a quarter years from 61 Cygni, and forty-five +years from the Polar Star. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_74"><span class="page">Page 74</span></a> +world. It is something more than a mere book; it is an ever-present +manifestation of the order and harmony of the universe." +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_75"><span class="page">Page 75</span></a> +V.</h2> + +<p class="subtitle"> +THE SUN. +</p> + +<p class="bquote"> +"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."—<i>Gen.</i> i. 16. +</p> + +<p class="bquote"> +<a name="page_76"><span class="page">Page 76</span></a> +"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. +</p> + +<p class="title"> +<a name="page_77"><span class="page">Page 77</span></a> +V. +</p> + +<p class="subtitle"> +<i>THE SUN.</i> +</p> + +<p class="indent"> +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 +<a name="page_78"><span class="page">Page 78</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_79"><span class="page">Page 79</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig30.jpg" width="359" height="580" alt="Figure 30"> +<br /> +Fig. 30.—Relative Size of Sun as seen from Different Planets. +</span> +</span> + +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 527px; + font-size: smaller; text-align: justify; "> +<a name="page_80"><span class="page">Page 80</span></a> +<img src="images/fig31.jpg" width="527" height="687" alt="Figure 31"> +<br /> +Fig. 31.—Zodiacal Light. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +But come to more ponderable matters. If we look +<a name="page_81"><span class="page">Page 81</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_82"><span class="page">Page 82</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 525px; + font-size: smaller; text-align: justify; "> +<img src="images/fig32.jpg" width="525" height="516" alt="Figure 32"> +<br /> +Fig. 32.—The Corona in 1858, Brazil. +</span> +</div> + +<p class="indent"> +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 +<a name="page_83"><span class="page">Page 83</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 458px; + font-size: smaller; text-align: justify; "> +<img src="images/fig33.jpg" width="458" height="515" alt="Figure 33"> +<br /> +Fig. 33.—The Corolla in 1878, Colorado. +</span> +</div> + +<p class="indent"> +<a name="page_84"><span class="page">Page 84</span></a> +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. +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<a name="page_85"><span class="page">Page 85</span></a> +<img src="images/fig34.jpg" width="521" height="780" alt="Figure 34"> +<br /> +Fig. 34.—Solar Prominences of Flaming Hydrogen. +</span> +</span> + +<a name="page_87"><span class="page">Page 87</span></a> +left, the air—if I may use the expression—was filled +with the flying <i>débris</i>, a mass of detached vertical +fusi-form fragments, each from ten to thirty seconds (<i>i. e.</i>, +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 +<a name="page_88"><span class="page">Page 88</span></a> +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." +</p> + +<p class="indent"> +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." +</p> + +<p class="indent"> +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 +<a name="page_89"><span class="page">Page 89</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_90"><span class="page">Page 90</span></a> +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). +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 515px; + font-size: smaller; text-align: justify; "> +<img src="images/fig35.jpg" width="515" height="158" alt="Figure 35"> +<br /> +Fig. 35.—Change in Spots as rotated across the Disk, showing +Cavities. +</span> +</div> + +<p class="indent"> +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 +<a name="page_91"><span class="page">Page 91</span></a> +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. +</p> + +<p class="indent"> +These spots may be seen with almost any telescope, the eye being +protected by deeply colored glasses. +</p> + +<p class="indent"> +Until within one hundred years they were supposed to be islands +of scoriæ 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. +</p> + +<p class="indent"> +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 +<a name="page_92"><span class="page">Page 92</span></a> +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." +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 501px; + font-size: smaller; text-align: justify; "> +<img src="images/fig36.jpg" width="501" height="474" alt="Figure 36"> +<br /> +Fig. 36.—Solar spot, by Langley. +</span> +</div> + +<p class="indent"> +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 +<a name="page_93"><span class="page">Page 93</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3> +<a name="page_94"><span class="page">Page 94</span></a> +<i>What the Sun does for us.</i></h3> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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, +<a name="page_95"><span class="page">Page 95</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="center"> +EXPERIMENTS. +</p> + +<p class="indent"> +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 +<a name="page_96"><span class="page">Page 96</span></a> +its usual focusing for distant objects. The farther it is drawn, +the nearer must we hold the screen for a perfect image. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 354px; + font-size: smaller; text-align: justify; "> +<img src="images/fig37.jpg" width="354" height="491" alt="Figure 37"> +<br /> +Fig. 37.—Holding Telescope to see the Sun's Spots. +</span> +</div> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_97"><span class="page">Page 97</span></a> +VI.</h2> + +<p class="subtitle"> +THE PLANETS, AS SEEN FROM SPACE. +</p> + +<p class="bquote"> +"He hangeth the earth upon nothing."—<i>Job</i> xxvi. 7. +</p> + +<p class="bquote"> +<a name="page_98"><span class="page">Page 98</span></a> +"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. +</p> + +<p class="title"> +<a name="page_99"><span class="page">Page 99</span></a> +VI. +</p> + +<p class="subtitle"> +<i>THE PLANETS, AS SEEN FROM SPACE</i> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +<a name="page_100"><span class="page">Page 100</span></a> + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig38.jpg" width="513" height="696" alt="Figure 38"> +<br /> +Fig. 38.—Orbits and Comparative Sizes of the Planets. +</span> +</span> + +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 +<a name="page_101"><span class="page">Page 101</span></a> +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: +</p> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <td>Mercury</td> + <td class="br">29.55</td> + <td>Jupiter</td> + <td>8.06</td> +</tr><tr> + <td>Venus</td> + <td class="br">21.61</td> + <td>Saturn</td> + <td>5.95</td> +</tr><tr> + <td>Earth</td> + <td class="br">18.38</td> + <td>Uranus</td> + <td>4.20</td> +</tr><tr> + <td>Mars</td> + <td class="br">14.99</td> + <td>Neptune</td> + <td>3.36</td> +</tr> +</table> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_102"><span class="page">Page 102</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<a name="page_103"><span class="page">Page 103</span></a> +<span style="font-size: smaller;"> +<img src="images/fig39.jpg" width="750" height="610" alt="Figure 39"> +<br /> +Fig. 39.—Orbit of Earth, showing Parallelism of Axis and Seasons. +</span> +</span> + +<a name="page_105"><span class="page">Page 105</span></a> +north of the equator gets more darkness than light, and hence winter. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +<a name="page_106"><span class="page">Page 106</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +If the earth, and Saturn, and Pallas were lying in +<a name="page_107"><span class="page">Page 107</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig40.jpg" width="489" height="152" alt="Figure 40"> +<br /> +Fig. 40.—Inclination of the Planes of Orbits. +</span> +</span> + +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 457px; + font-size: smaller; text-align: justify; "> +<img src="images/fig41.jpg" width="457" height="184" alt="Figure 41"> +<br /> +Fig. 41.—Inclination of Orbits of Venus and Earth. Nodal Line, +D B. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +This general view of the flying spheres is full of interest. +<a name="page_108"><span class="page">Page 108</span></a> +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. +</p> + +<h3><i>The Outlook from the Earth.</i></h3> + +<p class="indent"> +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. +</p> + +<p class="indent"> +We see, first of all, sun, moon, and stars rise in the east, mount +the heavens, and set in the west. As I +<a name="page_109"><span class="page">Page 109</span></a> +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. +</p> + +<p class="indent"> +But the watchers on the Acropolis do not get turned over so as to +see the moon at the same time every night. +<a name="page_110"><span class="page">Page 110</span></a> +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°. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 502px; + font-size: smaller; text-align: justify; "> +<img src="images/fig42.jpg" width="502" height="507" alt="Figure 42"> +<br /> +Fig. 42.—Showing the Sun's Movement among the Stars. +</span> +</div> + +<p class="indent"> +<a name="page_111"><span class="page">Page 111</span></a> +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. +</p> + +<p class="indent"> +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. + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig43.jpg" width="48" height="96" alt="Figure 43"> +<br /> +Fig. 43. +</span> +</span> + +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. +</p> + +<p class="indent"> +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, +<a name="page_112"><span class="page">Page 112</span></a> +and go on again. Some are never seen far from the sun, and others +in all parts of the ecliptic. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 429px; + font-size: smaller; text-align: justify; "> +<img src="images/fig44.jpg" width="429" height="40" alt="Figure 44"> +<br /> +Fig. 44. +</span> +</div> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 514px; + font-size: smaller; text-align: justify; "> +<img src="images/fig45.jpg" width="514" height="325" alt="Figure 45"> +<br /> +Fig. 45. Showing Position of Planets. +</span> +</div> + +<p class="indent"> +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 <i>a</i>, +<a name="page_113"><span class="page">Page 113</span></a> +on the background of the stars it seems to be among. It remains +apparently stationary at <i>a</i> for some time, because approaching +the earth in nearly a straight line. Passing D to C, it appears to +retrograde among the stars to <i>c</i>; remains apparently stationary +for some time, then, in passing from C to E and A, appears to pass back +among the stars to <i>a</i>. The progress of the earth, meanwhile, +although it greatly retards the apparent motion from A to C, greatly +hastens it from C to A. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 509px; + font-size: smaller; text-align: justify; "> +<img src="images/fig46.jpg" width="509" height="296" alt="Figure 46"> +<br /> +Fig. 46.—Apparent Movements of an Inferior Planet. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_114"><span class="page">Page 114</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 359px; + font-size: smaller; text-align: justify; "> +<img src="images/fig47.jpg" width="359" height="221" alt="Figure 47"> +<br /> +Fig. 47.—Illustrating Movements of a Superior Planet. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_115"><span class="page">Page 115</span></a> +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. +</p> + +<p class="center">EXPERIMENTS.</p> + +<p class="indent"> +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. +</p> + +<hr> + +<p class="bquote">PROCESSION OF STARS AND SOULS.</p> + +<p class="bquote"> +"I stood upon the open casement,<br> + And looked upon the night,<br> + And saw the westward-going stars<br> + Pass slowly out of sight. +</p> + +<p class="bquote"> +"Slowly the bright procession<br> + Went down the gleaming arch,<br> + And my soul discerned the music<br> + Of the long triumphal march; +</p> + +<p class="bquote"> +"Till the great celestial army,<br> + Stretching far beyond the poles,<br> + Became the eternal symbol<br> + Of the mighty march of souls. +</p> + +<p class="bquote"> +<a name="page_116"><span class="page">Page 116</span></a> +"Onward, forever onward,<br> + Red Mars led on his clan;<br> + And the moon, like a mailèd maiden,<br> + Was riding in the van. +</p> + +<p class="bquote"> +"And some were bright in beauty,<br> + And some were faint and small,<br> + But these might be, in their great heights,<br> + The noblest of them all. +</p> + +<p class="bquote"> +"Downward, forever downward,<br> + Behind earth's dusky shore,<br> + They passed into the unknown night—<br> + They passed, and were no more. +</p> + +<p class="bquote"> +"No more! Oh, say not so!<br> + And downward is not just;<br> + For the sight is weak and the sense is dim<br> + That looks through heated dust. +</p> + +<p class="bquote"> +"The stars and the mailèd moon,<br> + Though they seem to fall and die,<br> + Still sweep in their embattled lines<br> + An endless reach of sky. +</p> + +<p class="bquote"> +"And though the hills of Death<br> + May hide the bright array,<br> + The marshalled brotherhood of souls<br> + Still keeps its onward way. +</p> + +<p class="bquote"> +"Upward, forever upward,<br> + I see their march sublime,<br> + And hear the glorious music<br> + Of the conquerors of Time. +</p> + +<p class="bquote"> +"And long let me remember<br> + That the palest fainting one<br> + May to diviner vision be<br> + A bright and blazing sun." +</p> + +<p class="bquote"> + THOMAS BUCHANAN READ. +</p> + +<h2> +<a name="page_117"><span class="page">Page 117</span></a> +VII.</h2> + +<p class="subtitle"> +SHOOTING-STARS, METEORS, AND COMETS. +</p> + +<p class="bquote"> +"The Lord cast down great stones from heaven upon them unto Azekah, +and they died."—<i>Joshua</i> x. II. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 712px; + font-size: smaller; text-align: justify; "> +<a name="page_118"><span class="page">Page 118</span></a> +<img src="images/swarm.jpg" width="712" height="551" alt="meteor swarm"> +<br /> +A SWARM OF METEORS MEETING THE EARTH. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="title"> +<a name="page_119"><span class="page">Page 119</span></a> +VII. +</p> + +<p class="subtitle"> +<i>SHOOTING-STARS, METEORS, AND COMETS.</i> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_120"><span class="page">Page 120</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig48.jpg" width="521" height="535" alt="Figure 48"> +<br /> +Fig. 48.—Explosion of a Bolide. +</span> +</span> + +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 +<a name="page_121"><span class="page">Page 121</span></a> +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." +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 435px; + font-size: smaller; text-align: justify; "> +<img src="images/fig49.jpg" width="435" height="211" alt="Figure 49"> +<br /> +Fig. 49.—Bolides. +</span> +</div> + +<p class="indent"> +<a name="page_122"><span class="page">Page 122</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 426px; + font-size: smaller; text-align: justify; "> +<img src="images/fig50.jpg" width="426" height="464" alt="Figure 50"> +<br /> +Fig. 50.—Santa Rosa Aerolite. +</span> +</div> + +<h3><i>Aerolites.</i></h3> + +<p class="indent"> +Sometimes the bodies are large enough to bear the heat, and the +unconsumed centre comes to the earth. +<a name="page_123"><span class="page">Page 123</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_124"><span class="page">Page 124</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_125"><span class="page">Page 125</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig51.jpg" width="341" height="551" alt="Figure 51"> +<br /> +Fig. 51.—Orbit of the November Meteors and the Comet or 1866. +</span> +</span> + +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, +<a name="page_126"><span class="page">Page 126</span></a> +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. +</p> + +<h3><i>Comets.</i></h3> + +<p class="indent"> +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, + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<a name="page_127"><span class="page">Page 127</span></a> +<span style="font-size: smaller;"> +<img src="images/fig52.jpg" width="533" height="531" alt="Figure 52"> +<br /> +Fig. 52.—Aspects of Remarkable Comets. +</span> +</span> + +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 +<a name="page_128"><span class="page">Page 128</span></a> +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 <i>vice versa</i>. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Famous Comets.</i></h3> + +<p class="indent"> +The comet of 1680 is perhaps the one that appeared in A.D. 44, +soon after the death of Julius Cæsar, 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. +</p> + +<p class="indent"> +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 +<a name="page_129"><span class="page">Page 129</span></a> +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. +</p> + +<p class="indent"> +<i>Biela's lost Comet.</i>—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 +<a name="page_130"><span class="page">Page 130</span></a> +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. +</p> + +<p class="indent"> +<i>The Great Comet of</i> 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. +</p> + +<p class="indent"> +<i>Donati's Comet of</i> 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. +</p> + +<p class="indent"> +<i>Encke's Comet.</i>—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 +<a name="page_131"><span class="page">Page 131</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Of what do Comets consist?</i></h3> + +<p class="indent"> +The unsolved problems pertaining to comets are very numerous and +exceedingly delicate. Whence come they? Why did they not contract +to centres of nebulæ? 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 +<a name="page_132"><span class="page">Page 132</span></a> +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. +</p> + +<p class="indent"> +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, +<a name="page_133"><span class="page">Page 133</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Will Comets strike the Earth?</i></h3> + +<p class="indent"> +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 +<a name="page_134"><span class="page">Page 134</span></a> +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. +</p> + +<h2> +<a name="page_135"><span class="page">Page 135</span></a> +VIII.</h2> + +<p class="subtitle"> +THE PLANETS AS INDIVIDUALS. +</p> + +<p class="bquote"> +"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."—<i>Heb.</i> xi. 3. +</p> + +<p class="bquote"> +<a name="page_136"><span class="page">Page 136</span></a> +"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. +</p> + +<p class="title"> +VII. +</p> + +<p class="subtitle"> +<a name="page_137"><span class="page">Page 137</span></a> +<i>THE PLANETS AS INDIVIDUALS.</i> +</p> + +<p class="indent"> +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? +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +When the total eclipse of the sun occurred in 1878, +<a name="page_138"><span class="page">Page 138</span></a> +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. +</p> + +<h3>VULCAN.</h3> + +<p class="indent"> +The god of fire; its sign <img src="images/vulcan.gif" width="18" +height="15" alt="Vulcan">, his hammer. +</p> + +<p class="indent"> +<b>Distance from the sun, 13,000,000 miles. Orbital revolution, +about 20 days.</b> +</p> + +<h3>MERCURY.</h3> + +<p class="indent"> +The swift messenger of the gods; sign <img src="images/mercury.gif" +width="12" height="17" alt="Mercury">, his caduceus. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_139"><span class="page">Page 139</span></a> +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: +</p> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <td>November 7th</td> + <td class="br">1881</td> + <td>November 10th</td> + <td>1894</td> +</tr><tr> + <td>May 9th</td> + <td class="br">1891</td> + <td>November 4th</td> + <td>1901</td> +</tr> +</table> + +<h3>VENUS.</h3> + +<p class="indent"> +Goddess of beauty; its sign <img src="images/venus.gif" width="12" +height="18" alt="Venus">, a mirror. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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. Phœbus, 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 <i>fête</i>, 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 +<a name="page_140"><span class="page">Page 140</span></a> +his piercing eye caught the clear lustre of Venus smiling upon him +at mid-day. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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). +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 540px; + font-size: smaller; text-align: justify; "> +<img src="images/fig53.jpg" width="540" height="188" alt="Figure 53"> +<br /> +Fig. 53.—Phases of Venus, and Varions Apparent Dimensions. +</span> +</div> + +<p class="indent"> +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: +</p> + +<p class="bquote"> +<a name="page_141"><span class="page">Page 141</span></a> +"Hæc immatura a me jam frustra leguntur o. y."<br /> +(These unripe things are now vainly gathered by me.) +</p> + +<p> +He first saw Venus as gibbous; a few months revealed it as crescent, +and then he transposed his anagram into: +</p> + +<p class="bquote"> +"Cynthiæ figuras æmulatur mater amorum."<br /> +(The mother of loves imitates the phases of Cynthia.) +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3>THE EARTH.</h3> + +<p class="indent"> +Its sign <img src="images/earth.gif" width="16" height="16" +alt="Earth">. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<a name="page_142"><span class="page">Page 142</span></a> +<span style="font-size: smaller;"> +<img src="images/fig54.jpg" width="505" height="603" alt="Figure 54"> +<br /> +Fig. 54.—Earth and Moon in Space. +</span> +</span> + +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 +<a name="page_143"><span class="page">Page 143</span></a> +the sunset follow over an equal space, 180° behind. We are glad +that the darkness never overtakes the morning. +</p> + +<h3><i>The Aurora Borealis.</i></h3> + +<p class="indent"> +While east and west are gorgeous with sunrise and sunset, the north +is often more glorious with its aurora borealis. We remember that + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig55.jpg" width="515" height="524" alt="Figure 55"> +<br /> +Fig. 55.—The Aurora as Waving Curtains. +</span> +</span> + +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 +<a name="page_144"><span class="page">Page 144</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>The Delicate Balance of Forces.</i></h3> + +<p class="indent"> +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 +<a name="page_145"><span class="page">Page 145</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3> +<a name="page_146"><span class="page">Page 146</span></a> +<i>Tides.</i></h3> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<a name="page_147"><span class="page">Page 147</span></a> +<img src="images/fig56.jpg" width="562" height="155" alt="Figure 56"> +<br /> +Fig. 56. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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>i. e.</i>, 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. +</p> + +<p class="indent"> +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 +<a name="page_148"><span class="page">Page 148</span></a> +it does not yield instantly to the moon's influence, and the crest +of the tide is some hours behind the advancing moon. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 519px; + font-size: smaller; text-align: justify; "> +<a name="page_150"><span class="page">Page 150</span></a> +<img src="images/fig57.jpg" width="519" height="771" alt="Figure 57"> +<br /> +Fig. 57.—Lunar Day. +</span> +</div> + +<h3> +<a name="page_151"><span class="page">Page 151</span></a> +THE MOON.</h3> + +<p class="indent"> +New moon, <img src="images/new_moon.gif" width="12" height="12" +alt="new moon">; first quarter, <img src="images/first_quarter.gif" +width="8" height="13" alt="first quarter">; full moon, <img +src="images/full_moon.gif" width="12" height="12" alt="full moon">; +last quarter, <img src="images/last_quarter.gif" width="8" height="13" +alt="last quarter">. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +Since, however, the moon is our nearest neighbor, a member of our +own family in fact, it is a most interesting object of study. +</p> + +<p class="indent"> +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 +<a name="page_152"><span class="page">Page 152</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_153"><span class="page">Page 153</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 508px; + font-size: smaller; text-align: justify; "> +<a name="page_154"><span class="page">Page 154</span></a> +<img src="images/fig58.jpg" width="508" height="672" alt="Figure 58"> +<br /> +Fig. 58.—View of the Moon near the Third Quarter. From a +Photograph by Professor Henry Draper. +</span> +</div> + +<p class="indent"> +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 +<a name="page_155"><span class="page">Page 155</span></a> +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. +</p> + +<h3><i>Telescopic Appearance.</i></h3> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig59.jpg" width="227" height="127" alt="Figure 59"> +<br /> +Fig. 59.—Illumination of Craters and Peaks. +</span> +</span> + +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 <i>a</i>, part of the one at <i>b</i>, casts +a long shadow from the mountain at <i>c</i>, and touches the tip +of the one at <i>d</i>, which appears to a distant observer as a +point of light beyond the terminator, As the moon revolves the +conical cavity, <i>a</i> is illuminated on the forward side only; +the light creeps down the backward side of cavity <i>b</i> to the +bottom; mountain <i>c</i>. comes directly under the sun and casts +no shadow, and mountain <i>d</i> casts its long shadow over the +plain. Knowing the time of revolution, and observing the change of +<a name="page_156"><span class="page">Page 156</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 544px; + font-size: smaller; text-align: justify; "> +<img src="images/fig60.jpg" width="544" height="474" alt="Figure 60"> +<br /> +Fig. 60.—Lunar Crater "Copernicus," after Secchi. +</span> +</div> + +<p class="indent"> +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, +<a name="page_157"><span class="page">Page 157</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Eclipses.</i></h3> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig61.jpg" width="496" height="319" alt="Figure 61"> +<br /> +Fig. 61.—Eclipses; Shadows of Earth and Moon. +</span> +</span> + +successive and total darkenings would greatly derange all affairs +dependent on light. It is easily avoided. Venus does +<a name="page_158"><span class="page">Page 158</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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, +<a name="page_159"><span class="page">Page 159</span></a> +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. +</p> + +<p class="indent"> +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! +</p> + +<h3>MARS.</h3> + +<p class="indent"> +The god or war; Its sign <img src="images/mars.gif" width="11" +height="17" alt="Mars">, spear and shield. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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 +<a name="page_160"><span class="page">Page 160</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig62.jpg" width="484" height="223" alt="Figure 62"> +<br /> +Fig. 62.—Apparent Size of Mars at Mean and Extreme Distances. +</span> +</span> + +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 <i>vice versa</i>. 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 +<a name="page_161"><span class="page">Page 161</span></a> +smaller 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. +</p> + +<h3><i>Satellites of Mars.</i></h3> + +<p class="indent"> +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 +<a name="page_162"><span class="page">Page 162</span></a> +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. +</p> + +<h3>ASTEROIDS.</h3> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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, +<a name="page_163"><span class="page">Page 163</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_164"><span class="page">Page 164</span></a> +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. +</p> + +<h3>JUPITER.</h3> + +<p class="indent"> +The king of the gods; sign <img src="images/jupiter.gif" width="16" +height="17" alt="Jupiter">, the bird of Jove. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 340px; + font-size: smaller; text-align: justify; "> +<img src="images/fig63.jpg" width="340" height="345" alt="Figure 63"> +<br /> +Fig. 63.—Jupiter as seen by the great Washington Telescope. +Drawn by Mr. Holden. +</span> +</div> + +<p class="indent"> +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 +<a name="page_165"><span class="page">Page 165</span></a> +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. +</p> + +<h3><i>Satellites of Jupiter.</i></h3> + +<p class="indent"> +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, +<a name="page_166"><span class="page">Page 166</span></a> +be occulted, emerge from shadow, and eclipse the planet, in an hour's +watching. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 497px; + font-size: smaller; text-align: justify; "> +<img src="images/fig64.jpg" width="497" height="256" alt="Figure 64"> +<br /> +Fig. 64.—<i>a.</i> Various Positions of Jupiter's Moons; <i>b.</i> +Greatest Elongation of each Satellite. +</span> +</div> + +<p class="center">ELEMENTS OF JUPITER'S SATELLITES.</p> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <th class="bltr" colspan="2"> </th> + <th class="btrb">Mean Distance<br />from Jupiter.</th> + <th class="btrb" colspan="3">Sidereal Period.</th> + <th class="btrb">Diameter.</th> +</tr><tr> + <td class="bl"> </td> + <td class="br"> </td> + <td class="right_br">Miles.</td> + <td class="right">Days</td> + <td class="right">Hrs.</td> + <td class="right_br">Min.</td> + <td class="right_br">Miles.</td> +</tr><tr> + <td class="right_bl">I.</td> + <td class="br">Io</td> + <td class="right_br">260,000</td> + <td class="right">1</td> + <td class="right">18</td> + <td class="right_br">28</td> + <td class="right_br">2,352</td> +</tr><tr> + <td class="right_bl">II.</td> + <td class="br">Europa</td> + <td class="right_br">414,000</td> + <td class="right">3</td> + <td class="right">13</td> + <td class="right_br">43</td> + <td class="right_br">2,099</td> +</tr><tr> + <td class="right_bl">III.</td> + <td class="br">Ganymede</td> + <td class="right_br">661,000</td> + <td class="right">7</td> + <td class="right">3</td> + <td class="right_br">59</td> + <td class="right_br">3,436</td> +</tr><tr> + <td class="right_blb">IV.</td> + <td class="brb">Callisto</td> + <td class="right_brb">1,162,000</td> + <td class="right_bb">16</td> + <td class="right_bb">18</td> + <td class="right_brb">5</td> + <td class="right_brb">2,929</td> +</tr> +</table> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_167"><span class="page">Page 167</span></a> +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. +</p> + +<h3>SATURN.</h3> + +<p class="indent"> +The god or time; sign <img src="images/saturn.gif" width="14" +height="18" alt="Saturn">, his scythe. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_168"><span class="page">Page 168</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig65.jpg" width="545" height="458" alt="Figure 65"> +<br /> +Fig. 65.—View of Saturn and his Rings. +</span> +</span> + +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. +</p> + +<p class="indent"> +<a name="page_169"><span class="page">Page 169</span></a> +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. +</p> + +<h3><i>Rings of Saturn.</i></h3> + +<p class="indent"> +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 <i>tricorps</i>. 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. +</p> + +<p class="indent"> +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, +<a name="page_170"><span class="page">Page 170</span></a> +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." +</p> + +<p class="indent"> +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."[*] +</p> + +<p class="footnote"> +[Footnote *: Lockyer.] +</p> + +<p class="indent"> +Our opportunities for seeing Saturn vary greatly. As the earth at +one part of its orbit presents its south pole +<a name="page_171"><span class="page">Page 171</span></a> +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. +</p> + +<p class="indent"> +The markings of the planet are delicate, difficult of detection, +and are not like those stark zebra stripes that are so often +represented. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +We are anxious to learn the nature of such a ring. +<a name="page_172"><span class="page">Page 172</span></a> +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. +</p> + +<p class="indent"> +We look forward to the opportunities for observation in 1882 with +the brightest hope that these difficult questions will be solved. +</p> + +<h3><i>Satellites of Saturn.</i></h3> + +<p class="indent"> +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: +</p> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <td colspan="2"> </td> + <td colspan="2">Distant from Saturn's centre.</td> +</tr><tr> + <td class="right">I.</td> + <td>Mimas</td> + <td class="right">119,725</td> + <td>miles.</td> +</tr><tr> + <td class="right">II.</td> + <td>Enceladus</td> + <td class="right">153,630</td> + <td> "</td> +</tr><tr> + <td class="right">III.</td> + <td>Tethys</td> + <td class="right">190,225</td> + <td> "</td> +</tr><tr> + <td class="right">IV.</td> + <td>Dione</td> + <td class="right">243,670</td> + <td> "</td> +</tr><tr> + <td class="right">V.</td> + <td>Rhea</td> + <td class="right">340,320</td> + <td> "</td> +</tr><tr> + <td class="right">VI.</td> + <td>Titan</td> + <td class="right">788,915</td> + <td> "</td> +</tr><tr> + <td class="right">VII.</td> + <td>Hyperion</td> + <td class="right">954,160</td> + <td> "</td> +</tr><tr> + <td class="right">VIII.</td> + <td>Japetus</td> + <td class="right">2,292,790</td> + <td> "</td> +</tr> +</table> + +<p class="indent"> +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 +<a name="page_173"><span class="page">Page 173</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3>URANUS.</h3> + +<p class="indent"> +Sign <img src="images/uranus.gif" width="19" height="18" alt="Uranus">; +the initial of Herschel, and sign of the world. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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 +<a name="page_174"><span class="page">Page 174</span></a> +boundaries of our solar system, in the moment of its discovery, +as much as all investigation had done in all previous ages. +</p> + +<p class="indent"> +Sir William Herschel was engaged in mapping stars in 1781, when he +first observed its sea-green disk. He proposed to call it <i>Georgium +Sidus</i>, 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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_175"><span class="page">Page 175</span></a> +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. +</p> + +<h3>NEPTUNE.</h3> + +<p class="indent"> +God of the sea; sign <img src="images/neptune.gif" width="11" +height="18" alt="Neptune">, his trident. +</p> + +<p class="indent"> +<b>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.</b> +</p> + +<p class="indent"> +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. +<a name="page_176"><span class="page">Page 176</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 254px; + font-size: smaller; text-align: justify; "> +<img src="images/fig66.jpg" width="254" height="255" alt="Figure 66"> +<br /> +Fig. 66.—Perturbation of Uranus. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_177"><span class="page">Page 177</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_178"><span class="page">Page 178</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_179"><span class="page">Page 179</span></a> +IX.</h2> + +<p class="subtitle"> +THE NEBULAR HYPOTHESIS. +</p> + +<p class="bquote"> +"And the earth was without form, and void; and darkness was upon +the face of the deep."—<i>Genesis</i> i. 2. +</p> + +<p class="bquote"> +<a name="page_180"><span class="page">Page 180</span></a> + "A dark<br> +Illimitable ocean, without bound,<br> +Without dimension, where length, breadth, and height,<br> +And time, and place are lost."—MILTON. +</p> + +<p class="bquote"> +"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. +</p> + +<p class="bquote"> +"The laws of nature do not account for their own origin."—JOHN +STUART MILL. +</p> + +<p class="title"> +<a name="page_181"><span class="page">Page 181</span></a> +IX. +</p> + +<p class="subtitle"> +<i>THE NEBULAR HYPOTHESIS.</i> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_182"><span class="page">Page 182</span></a> +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." +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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; +<a name="page_183"><span class="page">Page 183</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +The four great classes of facts confirmatory of this hypothesis +are as follows: 1st. All the planets move +<a name="page_184"><span class="page">Page 184</span></a> +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 nebulæ are observable in the heavens +which are not yet condensed into solids, but are still bright gas. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +Is this world-theory true? and if so, is either of the +<a name="page_185"><span class="page">Page 185</span></a> +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. +</p> + +<p class="indent"> +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 nebulæ 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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +The next difficulty is that of rotation. The laws +<a name="page_186"><span class="page">Page 186</span></a> +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 <i>already in revolution</i>. 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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_187"><span class="page">Page 187</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +The nebulæ 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 <i>Natural Science +Review</i>, +<a name="page_188"><span class="page">Page 188</span></a> +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 <i>tension. This fact is fatal to the nebular theory.</i>" +</p> + +<p class="indent"> +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 <i>vice versa</i>. A possible explanation +will be considered under variable stars. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_189"><span class="page">Page 189</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_190"><span class="page">Page 190</span></a> +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? +</p> + +<p class="indent"> +"1. Chemical action cannot be produced by mechanical power. +</p> + +<p class="indent"> +"2. Life, even in the lowest forms, cannot be produced from unorganized +matter. +</p> + +<p class="indent"> +"3. Protoplasm can be produced only by living matter. +</p> + +<p class="indent"> +"4. Organized matter is made up of cells, and can be produced only +by cells. Whence the first cell? +</p> + +<p class="indent"> +"5. A living being can be produced only from a seed or germ. Whence +the first vegetable seed? +</p> + +<p class="indent"> +"6. An animal cannot be produced from a plant. Whence the first +animal? +</p> + +<p class="indent"> +"7. Sensation cannot be produced in insentient matter. +</p> + +<p class="indent"> +"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. +</p> + +<p class="indent"> +"9. Consciousness—that is, a knowledge of self and its +operations—cannot be produced out of mere matter or sensation. +</p> + +<p class="indent"> +"10. We have no knowledge of man being generated out of the lower +animals. +</p> + +<p class="indent"> +"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. +</p> + +<p class="indent"> +<a name="page_191"><span class="page">Page 191</span></a> +"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. +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_193"><span class="page">Page 193</span></a> +X.</h2> + +<p class="subtitle"> +THE STELLAR SYSTEM. +</p> + +<p class="bquote"> +"The heavens number out the glory of the strong God."—DAVID. +</p> + +<p class="bquote"> +<a name="page_194"><span class="page">Page 194</span></a> +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.'" +</p> + +<p class="title"> +<a name="page_195"><span class="page">Page 195</span></a> +X. +</p> + +<h3><i>THE OPEN PAGE OF THE HEAVENS.</i></h3> + +<p class="indent"> +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 +<a name="page_196"><span class="page">Page 196</span></a> +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. +</p> + +<p class="indent"> +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 (α), Beta (β), Gamma +(γ), 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 +<a name="page_197"><span class="page">Page 197</span></a> +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." +</p> + +<p class="indent"> +A general acquaintance with the stars will be first attempted; +a more particular knowledge afterward. Fig. 67 (<a +href="#page_201">page 201</a>) 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 η, +Mizar ζ, Little Alcor close to it, +<a name="page_198"><span class="page">Page 198</span></a> +Alioth, ε Megrez, δ at the junction, has been growing +dimmer for a century, Phad, γ 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. +</p> + +<p class="indent"> +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 α 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 +<a name="page_199"><span class="page">Page 199</span></a> +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. +</p> + +<p class="indent"> +The star γ Draconis, also called Etanin, is famous in modern +astronomy, because observations on this star led to the discovery +of the <i>aberration of light</i>. 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. +</p> + +<p class="indent"> +<a name="page_200"><span class="page">Page 200</span></a> +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. +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<a name="page_201"><span class="page">Page 201</span></a> +<span style="font-size: smaller;"> +<img src="images/fig67.jpg" width="484" height="484" alt="Figure 67"> +<br /> +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. +</span> +</span> + +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<a name="page_202"><span class="page">Page 202</span></a> +<img src="images/fig68.jpg" width="482" height="338" alt="Figure 68"> +<br /> +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. +</span> +</div> + +<h3><i>Equatorial Constellations.</i></h3> + +<p class="indent"> +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 α +Alpheratz is in her face, the three at the left cross her breast. +β and the two above mark the girdle of her loins, and γ +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. +</p> + +<div style="width: 483px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 483px; + font-size: smaller; text-align: justify; "> +<a name="page_203"><span class="page">Page 203</span></a> +<img src="images/fig69.jpg" width="483" height="386" alt="Figure 69"> +<br /> +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. +</span> +</div> + +<p class="indent"> +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, γ, 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. +</p> + +<div style="width: 487px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 487px; + font-size: smaller; text-align: justify; "> +<a name="page_204"><span class="page">Page 204</span></a> +<img src="images/fig70.jpg" width="487" height="434" alt="Figure 70"> +<br /> +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. +</span> +</div> + +<p class="indent"> +Fig. 70 continues eastward. Note the sickle in the head and neck +of the Lion. The star β 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 γ +in the Virgin is double, with a period of 145 years. ζ is just +above the equinoctial. There is a fine nebula two-thirds of the +way from δ to η, 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. +</p> + +<div style="width: 486px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 486px; + font-size: smaller; text-align: justify; "> +<a name="page_205"><span class="page">Page 205</span></a> +<img src="images/fig71.jpg" width="486" height="335" alt="Figure 71"> +<br /> +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. +</span> +</div> + +<p class="indent"> +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 α, +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—α +in the face, β, γ, δ in his shoulders, π and +η in the loins, τ 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 γ of Hercules, and the partial circle of +the Northern Crown above. The head of Draco is seen at β 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. +</p> + +<div style="width: 489px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 489px; + font-size: smaller; text-align: justify; "> +<a name="page_206"><span class="page">Page 206</span></a> +<img src="images/fig72.jpg" width="489" height="426" alt="Figure 72"> +<br /> +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. +</span> +</div> + +<p class="indent"> +Fig. 72 portrays the stars eastward and southward. Scorpio is one +of the most brilliant and easily traced constellations. Antares, +α, 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 ζ, a double, and ε, a +quadruple star. The point to which the solar system is tending is +marked by the sign of the earth below π 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 α Centauri. The diamond form +of the Dolphin is sometimes called "Job's Coffin." The ecliptic +passes close +<a name="page_207"><span class="page">Page 207</span></a> +to β 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. +</p> + +<div style="width: 487px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 487px; + font-size: smaller; text-align: justify; "> +<img src="images/fig73.jpg" width="487" height="338" alt="Figure 73"> +<br /> +Fig. 73.—Fomalhaut comes to the Meridian, only 17° from +the horizon, at 8 o'clock November 4th. +</span> +</div> + +<p class="indent"> +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. β 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. α Pegasi is in the diagonal corner +from Alpharetz, in Andromeda. The star below Altair is β +Aquilæ, and is called Alschain; the one above is γ +Aquilæ, 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. +</p> + +<div style="width: 487px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 487px; + font-size: smaller; text-align: justify; "> +<a name="page_208"><span class="page">Page 208</span></a> +<img src="images/fig74.jpg" width="492" height="330" alt="Figure 74"> +<br /> +Fig. 74.—Southern Circumpolar Constellations invisible north +of the Equator. +</span> +</div> + +<p class="indent"> +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 η. Below it is the beautiful Southern Cross, near the +pole of the southern heavens. Just below are the two first magnitude +stars Bungala, α, and Achernar, β, 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. +</p> + +<p class="indent"> +<a name="page_209"><span class="page">Page 209</span></a> +For easy out-door finding of the stars above the horizon at any +time, see star-maps at end of the book. +</p> + +<h3><i>Characteristics of the Stars.</i></h3> + +<p class="indent"> +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. +</p> + +<h3> +<a name="page_210"><span class="page">Page 210</span></a> +<i>Number.</i></h3> + +<p class="indent"> +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."[*] +</p> + +<p class="footnote"> +[Footnote *: <i>Telescopic Work.</i>—Look at the Hyades and +Pleiades in Taurus. Notice the different colors of stars in them +both. Find the cluster Præsepe 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 α 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.] +</p> + +<h3><i>Double and Multiple Stars.</i></h3> + +<p class="indent"> +If we look up during the summer months nearly overhead at the star +ε Lyra, east of Vega (Fig. 72), we shall see with the naked +eye that the star appears a little +<a name="page_211"><span class="page">Page 211</span></a> +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 ξ in the Great +Bear (see Fig. 70) makes a revolution in fifty-eight years. +</p> + +<p class="indent"> +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 +<a name="page_212"><span class="page">Page 212</span></a> +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.[*] +</p> + +<p class="footnote"> +[Footnote *: <i>Telescopic Work.</i>—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. +</p> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <th class="btlbr">No.</th> + <th class="btrb">Name.</th> + <th class="btrb">Fig.</th> + <th class="btrb">Dist. of<br />Parts.</th> + <th class="btrb">Magnitudes.</th> + <th class="btrb">Remarks.</th> +</tr><tr> + <td class="right_brl">1.</td> + <td class="right_br">ε Lyræ</td> + <td class="right_br">72</td> + <td class="right_br">1' 56"</td> + <td class="right_br"> </td> + <td class="right_br">Quadruple.</td> +</tr><tr> + <td class="right_brl">2.</td> + <td class="right_br">ζ Lyræ</td> + <td class="right_br">72</td> + <td class="right_br">44</td> + <td class="right_br">5 & 6</td> + <td class="right_br">Topaz and green.</td> +</tr><tr> + <td class="right_brl">3.</td> + <td class="right_br">β Cygni</td> + <td class="right_br">73</td> + <td class="right_br">34-1/2</td> + <td class="right_br">3 & 6</td> + <td class="right_br">Yellow and blue.</td> +</tr><tr> + <td class="right_brl">4.</td> + <td class="right_br">61 Cygni</td> + <td class="right_br">73</td> + <td class="right_br">20</td> + <td class="right_br">5 & 6</td> + <td class="right_br">Nearest star but one.</td> +</tr><tr> + <td class="right_brl">5.</td> + <td class="right_br">Mizar</td> + <td class="right_br">67</td> + <td class="right_br">14</td> + <td class="right_br">3 & 4</td> + <td class="right_br">Both white.</td> +</tr><tr> + <td class="right_brl">6.</td> + <td class="right_br">Polaris</td> + <td class="right_br">67</td> + <td class="right_br">18-1/2</td> + <td class="right_br">2 & 9</td> + <td class="right_br">Test object of eye and glass.</td> +</tr><tr> + <td class="right_brl">7.</td> + <td class="right_br">ρ Orionis</td> + <td class="right_br">Frontispiece.</td> + <td class="right_br">7</td> + <td class="right_br">5 & 8</td> + <td class="right_br">Yellow and blue.</td> +</tr><tr> + <td class="right_brl">8.</td> + <td class="right_br">β Orionis</td> + <td class="right_br">" </td> + <td class="right_br">9</td> + <td class="right_br">1 & 8</td> + <td class="right_br">Rigel.</td> +</tr><tr> + <td class="right_brl">9.</td> + <td class="right_br">δ "</td> + <td class="right_br">" </td> + <td class="right_br">10</td> + <td class="right_br">2 & 8</td> + <td class="right_br">Red and white.</td> +</tr><tr> + <td class="right_brl">10.</td> + <td class="right_br">θ "</td> + <td class="right_br">" </td> + <td class="right_br"> </td> + <td class="right_br"> </td> + <td class="right_br">Septuple.</td> +</tr><tr> + <td class="right_brl">11.</td> + <td class="right_br">λ "</td> + <td class="right_br">" </td> + <td class="right_br">5</td> + <td class="right_br"> </td> + <td class="right_br">White and violet.</td> +</tr><tr> + <td class="right_brl">12.</td> + <td class="right_br">σ "</td> + <td class="right_br">" A, B.</td> + <td class="right_br">11</td> + <td class="right_br">4 & 10</td> + <td class="right_br">Octuple.</td> +</tr><tr> + <td class="right_brl">13.</td> + <td class="right_br">Castor</td> + <td class="right_br">69</td> + <td class="right_br">5-1/2</td> + <td class="right_br">2 & 3</td> + <td class="right_br">White.</td> +</tr><tr> + <td class="right_brl">14.</td> + <td class="right_br">Pollux</td> + <td class="right_br">69</td> + <td class="right_br"> </td> + <td class="right_br">Triple.</td> + <td class="right_br">Orange, gray, lilac.</td> +</tr><tr> + <td class="right_brbl">15.</td> + <td class="right_brb">γ Virginis</td> + <td class="right_brb">70</td> + <td class="right_brb">5</td> + <td class="right_brb">3 & 3</td> + <td class="right_brb">Both yellow.</td> +</tr> +</table> + +<p class="indent"> +When γ 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 α and δ 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 +<a name="page_213"><span class="page">Page 213</span></a> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 509px; + font-size: smaller; text-align: justify; "> +<img src="images/fig75.jpg" width="509" height="261" alt="Figure 75"> +<br /> +Fig. 75.—Aspects and Revolution of Double Stars. +</span> +</div> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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, +<a name="page_214"><span class="page">Page 214</span></a> +according to the power of the instrument. Perhaps the octuple star +σ 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. +</p> + +<h3><i>Colored Stars.</i></h3> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_215"><span class="page">Page 215</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Clusters of Stars.</i></h3> + +<p class="indent"> +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 +<a name="page_216"><span class="page">Page 216</span></a> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig76.jpg" width="244" height="291" alt="Figure 76"> +<br /> +Fig. 76.—Sprayed Cluster below η in Hercules. +</span> +</span> + +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. +</p> + +<p class="indent"> +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 + +<span style="float: left; width: 100%; text-align: center; margin: 1em;"> +<span style="font-size: smaller;"> +<img src="images/fig77.jpg" width="262" height="256" alt="Figure 77"> +<br /> +Fig. 77.—Globular Cluster. +</span> +</span> + +a good telescope without a shout of wonder." Here is a cluster +of the former class represented in Fig. 77. "The noble globular +cluster, ω 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 +<a name="page_217"><span class="page">Page 217</span></a> +magnitude, the minuteness of each star may be imagined." +</p> + +<p class="indent"> +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. +</p> + +<h3><i>Nebulæ.</i></h3> + +<p class="indent"> +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 +nebulæ 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 θ 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. Nebulæ are of all +conceivable shapes—circular, annular, oval, lenticular, +<a name="page_218"><span class="page">Page 218</span></a> +conical, spiral, snake-like, looped, and nameless. Compare the +sprays of the Crab nebulæ above ζ 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 β +and γ Lyræ. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 562px; + font-size: smaller; text-align: justify; "> +<img src="images/fig78.jpg" width="562" height="481" alt="Figure 78"> +<br /> +Fig. 78.—The great Nebula about the multiple Star θ +Orionis. (See Frontispiece.) +</span> +</div> + +<p class="indent"> +When Herschel was sweeping the heavens with his telescope, and +saw but few stars, he often said to his assistant, "Prepare to +write; the nebulæ 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 +<a name="page_219"><span class="page">Page 219</span></a> +of the stars in this zone, and but one-tenth of the nebulæ. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 463px; + font-size: smaller; text-align: justify; "> +<img src="images/fig79.jpg" width="463" height="520" alt="Figure 79"> +<br /> +Fig. 79.—Crab Nebula, near ζ Tauri. (See Frontispiece.) +</span> +</div> + +<p class="indent"> +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. +</p> + +<h3> +<a name="page_220"><span class="page">Page 220</span></a> +<i>Variable Stars.</i></h3> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 448px; + font-size: smaller; text-align: justify; "> +<img src="images/fig80.jpg" width="448" height="637" alt="Figure 80"> +<br /> +Fig. 80.—The Ring Nebula. +</span> +</div> + +<p class="indent"> +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 +<a name="page_221"><span class="page">Page 221</span></a> +stars are so marked as to challenge investigation. β Lyræ +(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. +</p> + +<div style="width: 100%; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 346px; + font-size: smaller; text-align: justify; "> +<img src="images/fig81.jpg" width="346" height="275" alt="Figure 81"> +<br /> +Fig. 81.—Constellation Lyra, showing place of the Ring Nebula. +</span> +</div> + +<p class="indent"> +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: +</p> + +<p class="bquote"> +<tt> + *<br /> +* * * +</tt> +</p> + +<p class="indent"> +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, δ in the Great Bear, has been growing dim +<a name="page_222"><span class="page">Page 222</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_223"><span class="page">Page 223</span></a> +to call down periodically vast showers; but none or all of these +suppositions apply to all cases, if they do to any. +</p> + +<h3><i>Temporary, New, and Lost Stars.</i></h3> + +<p class="indent"> +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 <i>temporary</i>, +shining awhile and then disappearing; <i>new</i>, coming to a definite +brightness, and so remaining; and <i>lost</i>, those whose first +appearance was not observed, but which have utterly disappeared. +</p> + +<p class="indent"> +In November, 1572, a new star blazed out in Cassiopeia. Its place +is shown in Fig. 67, χ γ being the stars +</p> + +<p class="bquote"> +<tt> +δ *<br /> + γ χ +</tt> +</p> + +<p> +in the seat of the chair, and δ 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. +</p> + +<p class="indent"> +A bright star was seen very near to the place of the <i>Pilgrim</i>, +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. +</p> + +<p class="indent"> +But we have had, within a few years, fine opportunities +<a name="page_224"><span class="page">Page 224</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_225"><span class="page">Page 225</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_226"><span class="page">Page 226</span></a> +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. +</p> + +<h3><i>Movements of Stars.</i></h3> + +<p class="indent"> +We call the stars <i>fixed</i>, 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. +</p> + +<p class="indent"> +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 <img src="images/earth.gif" width="16" +height="16" alt="Earth">, Fig. 72.) We are even +<a name="page_227"><span class="page">Page 227</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 α, β, γ, χ +Orionis will be altered in different directions; λ is moving +toward γ. λ and ε will appear as a double +star. In A.D. 50,000 Procyon will be nearer χ Orionis than +Rigel now is, and Sirius will be in line with α and χ +Orionis. All the stars of the Great Dipper, except Benetnasch and +Dubhe, have a common motion somewhat in the direction +<a name="page_228"><span class="page">Page 228</span></a> +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." +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_229"><span class="page">Page 229</span></a> +XI.</h2> + +<p class="subtitle"> +THE WORLDS AND THE WORD. +</p> + +<p class="bquote"> +"The worlds were framed by the word of God."—<i>Heb.</i> xi., 3. +</p> + +<p class="bquote"> +<a name="page_230"><span class="page">Page 230</span></a> +"Mysterious night! when our first parent knew thee<br> +From report divine, and heard thy name,<br> +Did he not tremble for this lovely frame,<br> +This glorious canopy of light and blue?<br> +Yet, 'neath a curtain of translucent dew,<br> +Bathed in the rays of the great setting flame,<br> +Hesperus, with all the host of heaven, came,<br> +And lo! creation widened in man's view.<br> +Who could have thought such darkness lay concealed<br> +Within thy beams, O Sun! Oh who could find,<br> +Whilst fruit and leaf and insect stood revealed,<br> +That to such countless worlds thou mad'st us blind!<br> +Why do we then shun death with anxious strife?<br> +If light conceal so much, wherefore not life?"<br> + BLANCO WHITE. +</p> + +<p class="title"> +<a name="page_231"><span class="page">Page 231</span></a> +XI. +</p> + +<p class="subtitle"> +<i>THE WORLDS AND THE WORD.</i> +</p> + +<p class="indent"> +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? +</p> + +<p class="indent"> +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 +<a name="page_232"><span class="page">Page 232</span></a> +promised to be perpetually present in his Word, making it alive +with spirit and life. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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: +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<a name="page_233"><span class="page">Page 233</span></a> +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 <i>willingly ignorant</i>, 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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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). +</p> + +<p class="indent"> +Men racked their feeble wits for expedients to uphold +<a name="page_234"><span class="page">Page 234</span></a> +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. +</p> + +<p class="indent"> +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." +</p> + +<p class="indent"> +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). +</p> + +<p class="indent"> +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 +<a name="page_235"><span class="page">Page 235</span></a> +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). +</p> + +<p class="indent"> +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 <i>turned</i> to it, as clay +to the seal. The earth's axial revolution is clearly recognized. +Copernicus declared it early; God earlier. +</p> + +<p class="indent"> +No man yet understands the balancing of the clouds, nor the suspension +of the frozen masses of hail, any more than Job did. +</p> + +<p class="indent"> +Had God asked if he had perceived the <i>length</i> of the earth, +many a man to-day could have answered yes. But the eternal ice +keeps us from perceiving the <i>breadth</i> +<a name="page_236"><span class="page">Page 236</span></a> +of the earth, and shows the discriminating wisdom of the question. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +We ask in vain, "What is matter?" No man can +<a name="page_237"><span class="page">Page 237</span></a> +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. +</p> + +<p class="indent"> +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." +</p> + +<p class="indent"> +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 +<a name="page_238"><span class="page">Page 238</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_239"><span class="page">Page 239</span></a> +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: +</p> + +<p class="bquote"> +"Science was Faith once; Faith were science now,<br> +Would she but lay her bow and arrows by,<br> +And aim her with the weapons of the time." +</p> + +<p class="indent"> +Faith laid her bow and arrows by before men in pursuit of worldly +knowledge discovered theirs. +</p> + +<p class="indent"> +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 +<a name="page_240"><span class="page">Page 240</span></a> +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. +</p> + +<p class="indent"> +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 +αστραπτων (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. +</p> + +<p class="indent"> +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. +<a name="page_241"><span class="page">Page 241</span></a> +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. +</p> + +<p class="bquote"> + "For his gayer hours<br> +She has a voice of gladness and a smile,<br> +And eloquence of beauty; and she glides<br> +Into his darker musings with a mild<br> +And gentle sympathy, that steals away<br> +Their sharpness ere he is aware." +</p> + +<p class="indent"> +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." +</p> + +<p class="indent"> +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 +<a name="page_242"><span class="page">Page 242</span></a> +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. +</p> + +<p class="indent"> +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 <i>Him!</i> The thunder of his power +who can comprehend?" +</p> + +<p class="indent"> +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. +<a name="page_243"><span class="page">Page 243</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_244"><span class="page">Page 244</span></a> +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 +ισαγγελοσ—equal +to angels. But the simplest teaching of Scripture points out a +way so clear that a child need not miss the glorious consummation. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_245"><span class="page">Page 245</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_247"><span class="page">Page 247</span></a> +XII.</h2> + +<p class="subtitle"> +THE ULTIMATE FORCE. +</p> + +<p class="bquote"> +"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." +</p> + +<p class="bquote"> +<a name="page_248"><span class="page">Page 248</span></a> +"O thou eternal one; whose presence blight<br> +All space doth occupy—all motion guide—<br> +Thou from primeval nothingness didst call<br> +First chaos, then existence. Lord, on thee<br> +Eternity had its foundation: all<br> +Sprung forth from thee—of light, joy, harmony,<br> +Sole origin: all life, all beauty thine.<br> +Thy word created all, and doth create;<br> +Thy splendor fills all space with rays divine;<br> +Thou art and wert, and shalt be glorious, great;<br> +Life-giving, life-sustaining Potentate,<br> +Thy chains the unmeasured universe surround—<br> +Upheld by thee, by thee inspired with breath."<br> + DERZHAVIN. +</p> + +<p class="title"> +<a name="page_249"><span class="page">Page 249</span></a> +XII. +</p> + +<p class="subtitle"> +<i>THE ULTIMATE FORCE.</i> +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_250"><span class="page">Page 250</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_251"><span class="page">Page 251</span></a> +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 nebulæ, 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 +<a name="page_252"><span class="page">Page 252</span></a> +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, nebulæ, 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. +</p> + +<p class="indent"> +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 <i>made</i> the sun? Contrivance +fills all thought. <i>Who</i> 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. +</p> + +<p class="indent"> +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 +<a name="page_253"><span class="page">Page 253</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +<a name="page_254"><span class="page">Page 254</span></a> +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." +</p> + +<p class="indent"> +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 +<a name="page_255"><span class="page">Page 255</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +<a name="page_256"><span class="page">Page 256</span></a> +Yet uncountable myriads on myriads of atoms have gone. +</p> + +<p class="indent"> +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 +<a name="page_257"><span class="page">Page 257</span></a> +to keep themselves in exact relation of distance and power to each +other, without touching. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_258"><span class="page">Page 258</span></a> +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." +</p> + +<p class="indent"> +<a name="page_259"><span class="page">Page 259</span></a> +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: +</p> + +<p class="bquote"> + "Father, thy hand<br> +Hath reared these venerable columns: Thou<br> +Did'st weave this verdant roof. Thou did'st look down<br> +Upon the naked earth, and forthwise rose<br> +All these fair ranks of trees. They in Thy sun<br> +Budded, and shook their green leaves in Thy breeze. +</p> + +<p class="bquote"> + "That delicate forest flower,<br> +With scented breath and looks so like a smile,<br> +Seems, as it issues from the shapeless mould,<br> +An emanation of the indwelling life,<br> +A visible token of the unfolding love<br> +That are the soul of this wide universe."—BRYANT. +</p> + +<p class="indent"> +<a name="page_260"><span class="page">Page 260</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_261"><span class="page">Page 261</span></a> +hope, a requiem without grandeur, over the world's future. But +nature herself, to all ears attuned, sings pæans, and shouts +to men that the highest energy, that of life, does not deteriorate. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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? +</p> + +<p class="indent"> +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 +<a name="page_262"><span class="page">Page 262</span></a> +to comprehend. The water is solid, liquid, gaseous on earth, and +in air according to the grade of power operating upon it. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_263"><span class="page">Page 263</span></a> +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. +</p> + +<p class="indent"> +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 æneas, 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 +<a name="page_264"><span class="page">Page 264</span></a> +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_265"><span class="page">Page 265</span></a> +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." +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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 +<a name="page_266"><span class="page">Page 266</span></a> +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. +</p> + +<p class="indent"> +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 +<a name="page_267"><span class="page">Page 267</span></a> +world. He comes to know God with his heart, better than he knows +God's works by his mind. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_269"><span class="page">Page 269</span></a> +SUMMARY OF LATEST DISCOVERIES AND CONCLUSIONS.</h2> + +<p class="indent"> +<i>Movements on the Sun.</i>—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 (<a href="#page_53">page 53</a>), +is one of the most delicate and difficult achievements of modern +science. +</p> + +<p class="indent"> +<i>Movement of Stars in Line of Sight</i> (<a href="#page_51">page +51</a>).—The following table shows this movement of stars, +so far as at present known: +</p> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <th colspan="3" class="btlbr">APROACHING.</th> + <th colspan="3" class="btrb">RECEDING.</th> +</tr><tr> + <th class="brbl">Map.</th> + <th class="brb">Name.</th> + <th class="brb">Rate per sec.</th> + <th class="brb">Map.</th> + <th class="brb">Name.</th> + <th class="brb">Rate per sec.</th> +</tr><tr> + <td class="right_brl">Fig. 71</td> + <td class="br">Arcturus</td> + <td class="br">55 miles</td> + <td class="right_br">Fig. 69</td> + <td class="br">Sirius</td> + <td class="br">20 miles</td> +</tr><tr> + <td class="right_brl">" 71</td> + <td class="br">Vega</td> + <td class="br">50 "</td> + <td class="right_br">Fr'piece</td> + <td class="br">Betelguese</td> + <td class="br">22 "</td> +</tr><tr> + <td class="right_brl">" 73</td> + <td class="br">α Cygni</td> + <td class="br">39 "</td> + <td class="right_br">" </td> + <td class="br">Rigel</td> + <td class="br">15 "</td> +</tr><tr> + <td class="right_brl">" 69</td> + <td class="br">Pollux</td> + <td class="br">49 "</td> + <td class="right_br">Fig. 69</td> + <td class="br">Castor</td> + <td class="br">25 "</td> +</tr><tr> + <td class="right_brbl">" 67</td> + <td class="brb">Dubhe</td> + <td class="brb">46 "</td> + <td class="right_brb">" 67</td> + <td class="brb">Regulus</td> + <td class="brb">15 "</td> +</tr> +</table> + +<p class="indent"> +<i>Sun's Appearance.</i>—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 <a href="#page_92">page 92</a>. +</p> + +<p class="indent"> +<i>Close Relation between Sun and Earth.</i>-Men always knew that +the earth received light from the sun. They subsequently discovered +that the earth was momentarily held by the power +<a name="page_270"><span class="page">Page 270</span></a> +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 (<a +href="#page_30">p. 30-36</a>). 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. +</p> + +<p class="indent"> +<i>Hydrogen Flames.</i>—It has been demonstrated that the +sun flames 200,000 miles high are hydrogen in a state of flaming +incandescence (<a href="#page_85">page 85</a>). +</p> + +<p class="indent"> +<i>Sun's Distance.</i>—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 "Encyclopædia +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. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<i>Oxygen in the Sun.</i>—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, +<a name="page_271"><span class="page">Page 271</span></a> +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. +</p> + +<p class="indent"> +<i>Substance of Stars.</i>—Aldebaran (<i>Frontispiece</i>) +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. +</p> + +<p class="indent"> +The theory that all nebulæ 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. +</p> + +<p class="indent"> +<i>Discoveries of New Bodies.</i>—Vulcan, the planet nearest +the sun (<a href="#page_138">page 138</a>). The two satellites of +Mars were discovered by Mr. Hall, U. S. Naval Observatory, August +11th, 1877 (<a href="#page_161">page 161</a>). "The outer one is +called Diemas; the inner, Phobus. +</p> + +<p class="indent"> +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. +</p> + +<p class="indent"> +<i>Saturn's Rings</i> are proved to be in a state of fluidity and +contraction (<a href="#page_171">page 171</a>). +</p> + +<p class="indent"> +<i>Meteors and Comets.</i>—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 (<a href="#page_133">page +133</a>). +</p> + +<p class="indent"> +<i>Aerolites.</i>-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. +</p> + +<table style="float: left; margin: 4px; width: 195px;"> +<tr><td class="center"> +<span style="font-size: smaller;"> +<img src="images/fig82.jpg" width="195" height="516" alt="Figure 82"> +<br /> +Fig. 82.—Horizontal Pendulum. +</span> +</td></tr> +</table> + +<p class="indent"> +<i>The Horizontal Pendulum.</i>—This delicate instrument is +<a name="page_272"><span class="page">Page 272</span></a> +represented in Fig. 82. It consists of an upright standard, strongly +braced; a weight, <i>m</i>, 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, <i>m</i>, 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 <i>vice versa</i> when +it crosses the nadir. The sun will be best studied without light, +in the quiet and darkness of some deep mine. +</p> + +<p class="indent"> +<a name="page_273"><span class="page">Page 273</span></a> +<i>Light of Unseen Stars.</i>—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. +</p> + +<p class="indent"> +<i>Lateral Movements of Stars</i>, <a href="#page_226">page 226-28</a>. +</p> + +<p class="indent"> +<i>Future Discoveries</i>—<i>A Trans-Neptunian +Planet.</i>—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." +</p> + +<p class="indent"> +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. +</p> + +<h2> +<a name="page_274"><span class="page">Page 274</span></a> +SOME ELEMENTS OF THE SOLAR SYSTEM</h2> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <th rowspan="2" class="btlbr">Name.</th> + <th rowspan="2" class="btrb">Sign.</th> + <th rowspan="2" class="btrb">Masses.</th> + <th colspan="2" class="btrb">Mean Dist. from Sun.</th> + <th rowspan="2" class="btrb">Mean<br />Diameter<br />in Miles.</th> + <th rowspan="2" class="btrb">Density.<br /> + <img src="images/earth.gif" width="16" height="16" alt="Earth"> + = 1.</th> + <th rowspan="2" class="btrb">Axial<br />Revolu­tion.</th> + <th rowspan="2" class="btrb">Gravity<br />at<br />Surface.<br /> + <img src="images/earth.gif" width="16" height="16" alt="Earth"> + = 1.</th> + <th rowspan="2" class="btrb">Periodic<br />Time.</th> + <th rowspan="2" class="btrb">Orbital<br />Velocity<br />in + Miles<br />per sec.</th> +</tr><tr> + <th class="brb">Earth's<br />Dist. as 1.</th> + <th class="brb">Millions<br />of Miles.</th> +</tr><tr> + <td class="blr">Sun</td> + <td class="center_br"> + <img src="images/sun_face.gif" width="17" height="17" + alt="sun with a face"></td> + <td class="center_br">Unity</td> + <td class="br"> </td> + <td class="center_br"> </td> + <td class="right_br">860,000</td> + <td class="br">0.255</td> + <td class="center_br">25 to 26d</td> + <td class="right_br">27.71</td> + <td class="right_br"> </td> + <td class="right_br"> </td> +</tr><tr> + <td class="blr">Mercury</td> + <td class="center_br"> + <img src="images/mercury.gif" width="12" height="17" + alt="Mercury"></td> + <td class="center_br">1/5000000(?)</td> + <td class="br">0.387</td> + <td class="center_br">35-3/4</td> + <td class="right_br">2,992</td> + <td class="br">1.21</td> + <td class="center_br">24h 5m(?)</td> + <td class="right_br">0.46</td> + <td class="right_br">87.97d</td> + <td class="right_br">29.55</td> +</tr><tr> + <td class="blr">Venus</td> + <td class="center_br"> + <img src="images/venus.gif" width="12" height="18" alt="Venus"></td> + <td class="center_br">1/425000</td> + <td class="br">0.723</td> + <td class="center_br">66-3/4</td> + <td class="right_br">7,660</td> + <td class="br">0.85</td> + <td class="center_br">23h 21m(?)</td> + <td class="right_br">0.82</td> + <td class="right_br">224.70d</td> + <td class="right_br">21.61</td> +</tr><tr> + <td class="blr">Earth</td> + <td class="center_br"> + <img src="images/earth.gif" width="16" height="16" alt="Earth"></td> + <td class="center_br">1/326800</td> + <td class="br">1.</td> + <td class="center_br">92-1/3</td> + <td class="right_br">7,918</td> + <td class="br">1.</td> + <td class="center_br">23h 56m 4s</td> + <td class="right_br">1.</td> + <td class="right_br">365.26d</td> + <td class="right_br">18.38</td> +</tr><tr> + <td class="blr">Mars</td> + <td class="center_br"> + <img src="images/mars.gif" width="11" height="17" alt="Mars"></td> + <td class="center_br">1/2950000</td> + <td class="br">1.523</td> + <td class="center_br">141</td> + <td class="right_br">4,211</td> + <td class="br">0.737</td> + <td class="center_br">24h 37m 22.7s</td> + <td class="right_br">0.39</td> + <td class="right_br">686.98d</td> + <td class="right_br">14.99</td> +</tr><tr> + <td class="blr">Asteroids</td> + <td class="center_br">(No.)</td> + <td class="center_br"> </td> + <td class="br"> </td> + <td class="center_br"> </td> + <td class="right_br"> </td> + <td class="br"> </td> + <td class="center_br"> </td> + <td class="right_br"> </td> + <td class="right_br"> </td> + <td class="right_br"> </td> +</tr><tr> + <td class="blr">Jupiter</td> + <td class="center_br"> + <img src="images/jupiter.gif" width="16" height="17" alt="Jupiter"></td> + <td class="center_br">1/1047</td> + <td class="br">5.203</td> + <td class="center_br">480</td> + <td class="right_br">86,000</td> + <td class="br">0.243</td> + <td class="center_br">9h 55m 20s</td> + <td class="right_br">2.64</td> + <td class="right_br">11.86yrs</td> + <td class="right_br">8.06</td> +</tr><tr> + <td class="blr">Saturn</td> + <td class="center_br"> + <img src="images/saturn.gif" width="14" height="18" alt="Saturn"></td> + <td class="center_br">1/3501</td> + <td class="br">9.538</td> + <td class="center_br">881</td> + <td class="right_br">70,500</td> + <td class="br">0.133</td> + <td class="center_br">10h 14m</td> + <td class="right_br">1.18</td> + <td class="right_br">29.46yrs</td> + <td class="right_br">5.95</td> +</tr><tr> + <td class="blr">Uranus</td> + <td class="center_br"> + <img src="images/uranus.gif" width="19" height="18" alt="Uranus"></td> + <td class="center_br">1/22600</td> + <td class="br">19.183</td> + <td class="center_br">1771</td> + <td class="right_br">31,700</td> + <td class="br">0.226</td> + <td class="center_br">Unknown.</td> + <td class="right_br">0.90</td> + <td class="right_br">84.02yrs</td> + <td class="right_br">4.20</td> +</tr><tr> + <td class="blbr">Neptune</td> + <td class="center_brb"> + <img src="images/neptune.gif" width="11" height="18" alt="Neptune"></td> + <td class="center_brb">1/19380</td> + <td class="brb">30.054</td> + <td class="center_brb">2775</td> + <td class="right_brb">34,500</td> + <td class="brb">0.204</td> + <td class="center_brb">Unknown.</td> + <td class="right_brb">0.89</td> + <td class="right_brb">164.78yrs</td> + <td class="right_brb">3.36</td> +</tr> +</table> + +<h2> +<a name="page_275"><span class="page">Page 275</span></a> +EXPLANATION OF ASTRONOMICAL SYMBOLS.</h2> + +<h3>SIGNS OF THE ZODIAC</h3> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <td class="right">0.</td> + <td class="center"> + <img src="images/aries.gif" width="17" height="17" alt="Aries"></td> + <td>Aries</td> + <td class="right_br">0°</td> + <td class="right">VI.</td> + <td class="center"> + <img src="images/libra.gif" width="19" height="11" alt="Libra"></td> + <td>Libra</td> + <td class="right_br">180°</td> +</tr><tr> + <td class="right">I.</td> + <td class="center"> + <img src="images/taurus.gif" width="13" height="17" alt="Taurus"></td> + <td>Taurus</td> + <td class="right_br">30</td> + <td class="right">VII.</td> + <td class="center"> + <img src="images/scorpio.gif" width="18" height="17" alt="Scorpio"></td> + <td>Scorpio</td> + <td class="right_br">210</td> +</tr><tr> + <td class="right">II.</td> + <td class="center"> + <img src="images/gemini.gif" width="17" height="16" alt="Gemini"></td> + <td>Gemini</td> + <td class="right_br">60</td> + <td class="right">VIII.</td> + <td class="center"> + <img src="images/sagittarius.gif" width="11" height="17" + alt="Sagittarius"></td> + <td>Sagittarius</td> + <td class="right_br">240</td> +</tr><tr> + <td class="right">III.</td> + <td class="center"> + <img src="images/cancer.gif" width="21" height="16" alt="Cancer"></td> + <td>Cancer</td> + <td class="right_br">90</td> + <td class="right">IX.</td> + <td class="center"> + <img src="images/capricornus.gif" width="20" height="17" + alt="Capricornus"></td> + <td>Capricornus</td> + <td class="right_br">270</td> +</tr><tr> + <td class="right">IV.</td> + <td class="center"> + <img src="images/leo.gif" width="17" height="18" alt="Leo"></td> + <td>Leo</td> + <td class="right_br">120</td> + <td class="right">X.</td> + <td class="center"> + <img src="images/aquarius.gif" width="21" height="14" + alt="Aquarius"></td> + <td>Aquarius</td> + <td class="right_br">300</td> +</tr><tr> + <td class="right">V.</td> + <td class="center"><img src="images/virgo.gif" width="21" height="17" + alt="Virgo"></td> + <td>Virgo</td> + <td class="right_br">150</td> + <td class="right">XI.</td> + <td class="center"><img src="images/pisces.gif" width="16" height="18" + alt="pisces"></td> + <td>Pisces</td> + <td class="right_br">330</td> +</tr> +</table> + +<hr> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <td class="right"> + <img src="images/conjunction.gif" width="11" height="17" + alt="conjunction"></td> + <td class="br">Conjunction.</td> + <td class="right">S.</td> + <td>Seconds of Time.</td> +</tr><tr> + <td class="right"><img src="images/quadrature.gif" width="16" + height="16" alt="quadrature"></td> + <td class="br">Quadrature.</td> + <td class="right">°</td> + <td>Degrees.</td> +</tr><tr> + <td class="right"><img src="images/opposition.gif" width="13" + height="15" alt="opposition"></td> + <td class="br">Opposition.</td> + <td class="right">'</td> + <td>Minutes of Arc.</td> +</tr><tr> + <td class="right"><img src="images/ascending_node.gif" width="14" + height="17" alt="ascending node"></td> + <td class="br">Ascending Node.</td> + <td class="right">"</td> + <td>Seconds of Arc.</td> +</tr><tr> + <td class="right"><img src="images/descending_node.gif" width="15" + height="17" alt="descending node"></td> + <td class="br">Descending Node.</td> + <td class="right">R. A.</td> + <td>Right Ascension.</td> +</tr><tr> + <td class="right">H.</td> + <td class="br">Hours.</td> + <td class="right">Decl. or D.</td> + <td>Declination.</td> +</tr><tr> + <td class="right">M.</td> + <td class="br">Minutes of Time.</td> + <td class="right">N. P. D.</td> + <td>Dist. From North Pole.</td> +</tr> +</table> + +<h3>OTHER ABBREVIATIONS USED IN THE ALMANAC.</h3> + +<p class="indent"> +S., South, <i>i.e.</i>, crosses the meridian; M., morning; A, Afternoon; +Gr. H. L. N., greatest heliocentric latitude north, <i>i.e.</i>, +greatest distance north of the ecliptic, as seen from the sun. + <img src="images/conjunction.gif" width="11" height="17" alt="conjunction"> + <img src="images/mercury.gif" width="12" height="17" alt="Mercury"> + <img src="images/sun.gif" width="17" height="17" alt="Sun"> + Inf., inferior conjunction; Sup., superior conjunction. +</p> + +<h3>GREEK ALPHABET USED INDICATING THE STARS.</h3> + +<table border="0" cellspacing="0" cellpadding="4" class="center"> +<tr> + <td class="right">α,</td> + <td class="br">alpha.</td> + <td class="right">η,</td> + <td class="br">eta.</td> + <td class="right">ν,</td> + <td class="br">nu.</td> + <td class="right">τ,</td> + <td>tau.</td> +</tr><tr> + <td class="right">β,</td> + <td class="br">beta.</td> + <td class="right">θ,</td> + <td class="br">theta.</td> + <td class="right">ξ,</td> + <td class="br">xi.</td> + <td class="right">υ,</td> + <td>upsilon.</td> +</tr><tr> + <td class="right">γ,</td> + <td class="br">gamma.</td> + <td class="right">ι,</td> + <td class="br">iota.</td> + <td class="right">ο,</td> + <td class="br">omicron.</td> + <td class="right">φ,</td> + <td>phi.</td> +</tr><tr> + <td class="right">δ,</td> + <td class="br">delta.</td> + <td class="right">κ,</td> + <td class="br">kappa.</td> + <td class="right">π,</td> + <td class="br">pi.</td> + <td class="right">χ,</td> + <td>chi.</td> +</tr><tr> + <td class="right">ε,</td> + <td class="br">epsilon.</td> + <td class="right">λ,</td> + <td class="br">lambda.</td> + <td class="right">ρ,</td> + <td class="br">rho.</td> + <td class="right">ψ,</td> + <td>psi.</td> +</tr><tr> + <td class="right">ζ,</td> + <td class="br">zeta.</td> + <td class="right">μ,</td> + <td class="br">mu.</td> + <td class="right">σ,</td> + <td class="br">sigma.</td> + <td class="right">ω,</td> + <td>omega.</td> +</tr> +</table> + +<h2> +<a name="page_276"><span class="page">Page 276</span></a> +CHAUTAUQUA OUTLINE FOR STUDENTS.</h2> + +<p class="indent"> +As an aid to comprehension, every student should draw illustrative +figures of the various circles, planes, and situations described. +(For example, see Fig. 45, <a href="#page_112">page 112</a>.) 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. +</p> + +<p class="indent"> +I. <i>Creative Processes.</i>—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. +</p> + +<p class="indent"> +II. <i>Light.</i>—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. +</p> + +<p class="indent"> +III. <i>Astronomical Instruments.</i>—Refracting telescope. +Reflecting; largest. Spectroscope. Spectra of sun, hydrogen, sodium, +etc. E made G by approach; C by departure. Stars approach and recede. +</p> + +<p class="indent"> +IV. <i>Celestial Measurements.</i>-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, α Centauri, +61 Cygni. Orbits of asteroids. +</p> + +<p class="indent"> +V. <i>The Sun.</i>—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. +</p> + +<p class="indent"> +VI. <i>The Planets from Space.</i>—North Pole. Speed. Sizes. +Axial revolution. Man's weight on. Seasons. Parallelism of axis. +Earth near +<a name="page_277"><span class="page">Page 277</span></a> +sun in winter. Plane of ecliptic. Orbits inclined to. Earth rotates. +Proof. Sun's path among stars. Position of planets. Motion—direct, +retrograde. Experiments. +</p> + +<p class="indent"> +VII. <i>Meteors.</i>—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. <img src="images/earth.gif" width="16" +height="16" alt="Earth">. +</p> + +<p class="indent"> +VIII. <i>The Planets.</i>—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. +</p> + +<p class="indent"> +IX. <i>The Nebular Hypothesis.</i>—State it; facts confirmatory. +Objections—1. Heat; 2. Rotation; 3. Retrograde; 4. Martial +moons; 5. Star of 1876. Evolution: Gaps in; conclusion. +</p> + +<p class="indent"> +X. <i>The Stellar System.</i>-Motto. Man among stars; open page; +starry poem; stars located; named. Thuban. Etanin. Constellations: +Know them; number of stars; double; ε Lyræ, Sirius, +Procyon, Castor, 61 Cygni, γ Virginis. Colored stars; change +color. Clusters: Two theories. Nebulæ: Two visible; composed +of; shapes; where? Variable stars. Sun. β Lyræ, 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. +</p> + +<p class="indent"> +XI. <i>The Worlds and the Word.</i>—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; +<a name="page_278"><span class="page">Page 278</span></a> +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. +</p> + +<p class="indent"> +XII. <i>The Ultimate Force.</i>—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. +</p> + +<h2> +<a name="page_279"><span class="page">Page 279</span></a> +GLOSSARY OF ASTRONOMICAL TERMS AND INDEX.</h2> + +<p class="index"> +<b>Abbreviations</b> used in astronomies, <a href="#page_275">275</a>. +</p> + +<p class="index"> +<b>Aberration of light</b> (<i>a wandering away</i>), an apparent +displacement of a star, owing to the progressive motion of light +combined with that of the earth and its orbit, +<a href="#page_199">199</a>. +</p> + +<p class="index"> +<b>Aerolite</b> (<i>air-stone</i>), <a href="#page_122">122</a>. +</p> + +<p class="index"> +<b>Air</b>, refraction of the, <a href="#page_40">40</a>. +</p> + +<p class="index"> +<b>Algol</b>, the variable star, <a href="#page_222">222</a>. +</p> + +<p class="index"> +<b>Almanac</b>, Nautical, <a href="#page_71">71</a>; explanation +of signs used, <a href="#page_275">275</a>. +</p> + +<p class="index"> +<b>Alphabet</b>, Greek, <a href="#page_275">275</a>. +</p> + +<p class="index"> +<b>Altitude</b>, angular elevation of a body above the horizon. +</p> + +<p class="index"> +<b>Angle</b>, difference in directions of two straight lines that +meet. +</p> + +<p class="index"> +<b>Annular</b> (<i>ring-shaped</i>) <b>eclipses</b>, +<a href="#page_158">158</a>; nebulæ, +<a href="#page_218">218</a>, <a href="#page_220">220</a>. +</p> + +<p class="index"> +<b>Aphelion</b>, the point in an orbit farthest from the sun. +</p> + +<p class="index"> +<b>Apogee</b>, the point of an orbit which is farthest from the +earth. +</p> + +<p class="index"> +<b>Apsis</b>, plural <i>apsides</i>, the line joining the aphelion +and perihelion points; or the major axis of elliptical orbits. +</p> + +<p class="index"> +<b>Arc</b>, a part of a circle. +</p> + +<p class="index"> +<b>Ascension, right</b>, the angular distance of a heavenly body +from the first point of Aries, measured on the equator. +</p> + +<p class="index"> +<b>Asteroids</b> (<i>star-like</i>), <a href="#page_162">162</a>; +orbits of interlaced, <a href="#page_74">74</a>. +</p> + +<p class="index"> +<b>Astronomical instruments</b>, <a href="#page_43">43</a>. +</p> + +<p class="index"> +<b>Astronomy</b>, use of, <a href="#page_57">57</a>. +</p> + +<p class="index"> +<b>Atom</b>, size of, <a href="#page_255">255</a>; power of, <a +href="#page_256">256</a>. +</p> + +<p class="index"> +<b>Aurora Borealis</b>, <a href="#page_143">143</a>. +</p> + +<p class="index"> +<b>Axis</b>, the line about which a body rotates. +</p> + +<p class="index"> +<b>Azimuth</b>, the angular distance of any point or body in the +horizon from the north or south points. +</p> + +<p class="index"> +<b>Bailey's beads</b>, dots of light on the edge of the moon seen +in a solar eclipse, caused by the moon's inequalities of surface. +</p> + +<p class="index"> +<b>Base line</b>, <a href="#page_68">68</a>. +</p> + +<p class="index"> +<b>Biela's comet</b>, <a href="#page_129">129</a>. +</p> + +<p class="index"> +<b>Binary system</b>, a double star, the component parts of which +revolve around their centre of gravity. +</p> + +<p class="index"> +<b>Bode's law</b> of planetary distances is no law at all, but a +study of coincidences. +</p> + +<p class="index"> +<b>Bolides</b>, small masses of matter in space. They are usually +called meteors when luminous by contact with air, +<a href="#page_120">120</a>. +</p> + +<p class="index"> +<a name="page_280"><span class="page">Page 280</span></a> +<b>Celestial sphere</b>, the apparent dome in which the heavenly +bodies seem to be set; appears to revolve, <a href="#page_3">3</a>. +</p> + +<p class="index"> +<b>Centre of gravity</b>, the point on which a body, or two or more +related bodies, balances. +</p> + +<p class="index"> +<b>Centrifugal force</b> (<i>centre fleeing</i>). +</p> + +<p class="index"> +<b>Chromolithic plate</b> of spectra of metals, to face +<a href="#page_50">50</a>. +</p> + +<p class="index"> +<b>Circumpolar stars</b>, map of north, <a href="#page_201">201</a>. +</p> + +<p class="index"> +<b>Colors of stars</b>, <a href="#page_214">214</a>. +</p> + +<p class="index"> +<b>Colures</b>, the four principal meridians of the celestial sphere +passing from the pole, one through each equinox, and one through +each solstice. +</p> + +<p class="index"> +<b>Comets</b>, <a href="#page_126">126</a>; Halley's, +<a href="#page_128">128</a>; Biela's lost, <a href="#page_129">129</a>; +Encke's, <a href="#page_130">130</a>; constitution of, +<a href="#page_131">131</a>; will they strike the earth? +<a href="#page_133">133</a>. +</p> + +<p class="index"> +<b>Conjunction</b>. 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. +</p> + +<p class="index"> +<b>Constellation</b>, a group of stars supposed to represent some +figure: circumpolar, <a href="#page_201">201</a>; equatorial, for +December, <a href="#page_202">202</a>; for January, +<a href="#page_203">203</a>; April, <a href="#page_204">204</a>; +June, <a href="#page_205">205</a>; September, +<a href="#page_206">206</a>; November, <a href="#page_207">207</a>; +southern circumpolar, <a href="#page_208">208</a>. +</p> + +<p class="index"> +<b>Culmination</b>, the passage of a heavenly body across the meridian +or south point of a place; it is the highest point reached in its +path. +</p> + +<p class="index"> +<b>Cusp</b>, the extremities of the crescent form of the moon or +an interior planet. +</p> + +<p class="index"> +<b>Declination</b>, the angular distance of a celestial body north +or south from the celestial equator. +</p> + +<p class="index"> +<b>Degree</b>, the 1/360 part of a circle. +</p> + +<p class="index"> +<b>Direct motion</b>, a motion from west to east among stars. +</p> + +<p class="index"> +<b>Disk</b>, the visible surface of sun, moon, or planets. +</p> + +<p class="index"> +<b>Distance of stars</b>, <a href="#page_70">70</a>. +</p> + +<p class="index"> +<b>Double stars</b>, <a href="#page_210">210</a>. +</p> + +<p class="index"> +<b>Earth</b>, revolution of, <a href="#page_109">109</a>; in space, +<a href="#page_142">142</a>; irregular figure, +<a href="#page_145">145</a>. +</p> + +<p class="index"> +<b>Eccentricity of an ellipse</b>, the distance of either focus +from centre divided by half the major axis. +</p> + +<p class="index"> +<b>Eclipse</b> (<i>a disappearance</i>), <a href="#page_157">157</a>. +</p> + +<p class="index"> +<b>Ecliptic</b>, the apparent annual path of the sun among the stars; +plane of, <a href="#page_106">106</a>. +</p> + +<p class="index"> +<b>Egress</b>, the passing of one body off the disk of another. +</p> + +<p class="index"> +<b>Elements</b>, the quantities which determine the motion of a +planet: data for predicting astronomical phenomena; table of solar, +<a href="#page_274">274</a>. +</p> + +<p class="index"> +<b>Elements</b>, chemical, present in the sun, +<a href="#page_270">270</a>. +</p> + +<p class="index"> +<b>Elongation</b>, the angular distance of a planet from the sun. +</p> + +<p class="index"> +<b>Emersion</b>, the reappearance of a body after it has been eclipsed +or occulted by another. +</p> + +<p class="index"> +<a name="page_281"><span class="page">Page 281</span></a> +<b>Equator</b>, 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. +</p> + +<p class="index"> +<b>Equinox</b>, 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. +</p> + +<p class="index"> +<b>Evolution</b>, materialistic, <a href="#page_182">182</a>; +insufficient, <a href="#page_189">189</a>. +</p> + +<p class="index"> +<b>Fizeau</b> determines the velocity of light, +<a href="#page_23">23</a>. +</p> + +<p class="index"> +<b>Forces</b>, delicate balance of, <a href="#page_144">144</a>. +</p> + +<p class="index"> +<b>Galileo</b>, construction of his telescope, +<a href="#page_43">43</a>. +</p> + +<p class="index"> +<b>Geocentric</b>, a position of a heavenly body as seen or measured +from the earth's centre. +</p> + +<p class="index"> +<b>Geodesy</b>, the art of measuring the earth without reference +to the heavenly bodies. +</p> + +<p class="index"> +<b>God</b>, relation of, to the universe, <a href="#page_258">258</a>. +</p> + +<p class="index"> +<b>Gravitation</b>, laws of, <a href="#page_6">6</a>; extends to +the stars, <a href="#page_13">13</a>; theories of, +<a href="#page_253">253</a>. +</p> + +<p class="index"> +<b>Gravity</b> on different bodies, <a href="#page_6">6</a>, <a +href="#page_274">274</a>. +</p> + +<p class="index"> +<b>Helical</b>, rising or setting of a star, as near to sunrise +or sunset as it can be seen. +</p> + +<p class="index"> +<b>Heliocentric</b>, as seen from the centre of the sun. +</p> + +<p class="index"> +<b>Hoosac Tunnel</b>, example of accuracy, <a href="#page_62">62</a>. +</p> + +<p class="index"> +<b>Horizontal pendulum</b>, <a href="#page_272">272</a>. +</p> + +<p class="index"> +<b>Immersion</b>, the disappearance of one body behind another, +or in its shadow. +</p> + +<p class="index"> +<b>Inclination of an orbit</b>, the angle between its plane and +the plane of the ecliptic. +</p> + +<p class="index"> +<b>Inferior conjunction</b>, when an interior planet is between +the earth and the sun. +</p> + +<p class="index"> +<b>Jupiter</b>, apparent path of, in 1866, <a href="#page_112">112</a>; +elements of, <a href="#page_164">164</a>; satellites of, +<a href="#page_165">165</a>; positions of satellites, +<a href="#page_166">166</a>; elements of satellites, +<a href="#page_166">166</a>; the Jovian system, +<a href="#page_167">167</a>. +</p> + +<p class="index"> +<b>Kepler's Laws</b>—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. +</p> + +<p class="index"> +<b>Latitude</b>, the angular distance of a heavenly body from the +ecliptic. +</p> + +<p class="index"> +<b>Light</b>, the child of force, <a href="#page_17">17</a>; number of +vibrations of, <a href="#page_18">18</a>, <a href="#page_25">25</a>; +velocity of, <a href="#page_22">22</a>; undulatory and musical, <a +href="#page_26">26</a>; chemical force of, <a href="#page_30">30</a>; +experiments with, <a href="#page_37">37</a>; approach and departure of +a light-giving body measured, <a href="#page_51">51</a>; aberration +of, <a href="#page_199">199</a>. +</p> + +<p class="index"> +<b>Limb</b>, the edge of the disk of the moon, sun, or a planet. +</p> + +<p class="index"> +<b>Longitude</b>. 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, <a href="#page_72">72</a>. +</p> + +<p class="index"> +<b>Magellanic clouds</b>, <a href="#page_208">208</a>. +</p> + +<p class="index"> +<a name="page_282"><span class="page">Page 282</span></a> +<b>Mars</b>, <a href="#page_159">159</a>; snow spots of, +<a href="#page_160">160</a>; satellites of, <a href="#page_161">161</a>. +</p> + +<p class="index"> +<b>Mass</b>, the quantity of matter a body contains. +</p> + +<p class="index"> +<b>Mean distance of a planet</b>, half the sum of the aphelion and +perihelion distances. +</p> + +<p class="index"> +<b>Measurements</b>, celestial, <a href="#page_57">57</a>. +</p> + +<p class="index"> +<b>Mercury</b>, <a href="#page_138">138</a>. +</p> + +<p class="index"> +<b>Meridian</b>, 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. +</p> + +<p class="index"> +<b>Meteors</b>, <a href="#page_119">119</a>; swarm of, meeting the +earth, <a href="#page_118">118</a>; explosion of, +<a href="#page_120">120</a>; systems of, <a href="#page_123">123</a>; +relation of, to comets, <a href="#page_124">124</a>. +</p> + +<p class="index"> +<b>Micrometer</b>, any instrument for the accurate measurement of +very small distances or angles. +</p> + +<p class="index"> +<b>Mind</b>, origin of force, <a href="#page_252">252</a>; continuous +relation of, to the universe, <a href="#page_252">252</a>. +</p> + +<p class="index"> +<b>Milky Way</b>, <a href="#page_210">210</a>, +<a href="#page_215">215</a>. +</p> + +<p class="index"> +<b>Mira</b>, the Wonderful, <a href="#page_221">221</a>. +</p> + +<p class="index"> +<b>Moon</b>, the, <a href="#page_151">151</a>; greatest and least +distance from the earth, <a href="#page_10">10</a>; telescopic +appearance of, <a href="#page_155">155</a>. +</p> + +<p class="index"> +<b>Mural circle</b>, <a href="#page_61">61</a>. +</p> + +<p class="index"> +<b>Nadir</b>, the point in the celestial sphere directly beneath +our feet, opposite to zenith. +</p> + +<p class="index"> +<b>Nebulæ</b>, <a href="#page_217">217</a>. +</p> + +<p class="index"> +<b>Nebular hypothesis</b>, not atheistic, <a href="#page_182">182</a>; +stated, <a href="#page_182">182</a>; confirmatory facts, +<a href="#page_183">183</a>; objections to, <a href="#page_185">185</a>. +</p> + +<p class="index"> +<b>Neptune</b>, elements of, <a href="#page_175">175</a>. +</p> + +<p class="index"> +<b>Node</b>, the point in which an orbit intersects the ecliptic, +or other plane of reference; ascending, descending, line of, <a +href="#page_107">107</a>. +</p> + +<p class="index"> +<b>Occultation</b>, the hiding of a star, planet, or satellite by +the interposition of a nearer body of greater angular magnitude. +</p> + +<p class="index"> +<b>Opposition</b>. A superior planet is in opposition when the +sun, earth, and the planet are in a line, the earth being in the +middle. +</p> + +<p class="index"> +<b>Orbit</b>, the path of a planet, comet, or meteor around the sun, +or of a satellite around a primary; inclination of, +<a href="#page_106">106</a>; earth's, seen from the stars, +<a href="#page_70">70</a>. +</p> + +<p class="index"> +<b>Outline for students</b>, <a href="#page_276">276</a>. +</p> + +<p class="index"> +<b>Parallax</b>, 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, <a href="#page_69">69</a>. +</p> + +<p class="index"> +<b>Parallels</b>, imaginary circles on the earth or in the heavens +parallel to the equator, having the poles for their centre. +</p> + +<p class="index"> +<b>Perigee</b>, nearest the earth; said of a point in an orbit. +</p> + +<p class="index"> +<b>Perihelion</b>, the point of an orbit nearest the sun. +</p> + +<p class="index"> +<b>Periodic time</b>, time of a planet's, comet's, or satellite's +revolution. +</p> + +<p class="index"> +<b>Personal equation</b>, <a href="#page_65">65</a>. +</p> + +<p class="index"> +<b>Perturbation</b>, the effect of the attractions of the planets +or other +<a name="page_283"><span class="page">Page 283</span></a> +bodies upon each other, disturbing their regular motion; of Saturn +and Jupiter, <a href="#page_11">11</a>; of asteroids, +<a href="#page_13">13</a>; of Uranus and Neptune, +<a href="#page_176">176</a>. +</p> + +<p class="index"> +<b>Phases</b>, the portions of the illuminated half of the moon +or interior planet, as seen from the earth, called crescent, full, +and gibbous. +</p> + +<p class="index"> +<b>Photosphere</b> of the sun, <a href="#page_89">89</a>. +</p> + +<p class="index"> +<b>Planet</b> (<i>a wanderer</i>), as seen from space, +<a href="#page_99">99</a>; speed of, <a href="#page_101">101</a>; +size of, <a href="#page_102">102</a>; movements retrograde and +direct, <a href="#page_112">112</a>. +</p> + +<p class="index"> +<b>Pointers</b>, the, <a href="#page_197">197</a>. +</p> + +<p class="index"> +<b>Pole, North</b>, movement of, <a href="#page_198">198</a>. +</p> + +<p class="index"> +<b>Poles</b>, the extremities of an imaginary line on which a celestial +body rotates. +</p> + +<p class="index"> +<b>Quadrant</b>, the fourth part of the circumference of a circle, +or 90°. +</p> + +<p class="index"> +<b>Quadrature</b>, a position of the moon or other body when 90° +from the sun. +</p> + +<p class="index"> +<b>Radiant point</b>, that point of the heavens from which meteors +seem to diverge, <a href="#page_118">118</a>. +</p> + +<p class="index"> +<b>Radius-vector</b>, an imaginary line joining the sun and a planet +or comet in any part of its orbit. +</p> + +<p class="index"> +<b>Rain</b>, weight of, <a href="#page_249">249</a>. +</p> + +<p class="index"> +<b>Reflecting telescope</b>, <a href="#page_44">44</a>. +</p> + +<p class="index"> +<b>Refracting telescope</b>, <a href="#page_43">43</a>. +</p> + +<p class="index"> +<b>Refraction</b>, a bending of light by passing through any medium, +as air, water, prism. +</p> + +<p class="index"> +<b>Retrograde motion</b>, the apparent movement of a planet from +east to west among the stars. +</p> + +<p class="index"> +<b>Revolution</b>, the movement of bodies about their centre of +gravity. +</p> + +<p class="index"> +<b>Rotation</b>, the motion of a body around its axis. +</p> + +<p class="index"> +<b>Satellites</b>, smaller bodies revolving around planets and stars. +</p> + +<p class="index"> +<b>Saturn</b>, elements of, <a href="#page_167">167</a>; revolution +of, <a href="#page_168">168</a>; rings of, <a href="#page_169">169</a>; +decreasing, <a href="#page_171">171</a>; nature of, +<a href="#page_171">171</a>; satellites of, <a href="#page_172">172</a>. +</p> + +<p class="index"> +<b>Seasons</b>, of the earth, <a href="#page_102">102</a>; of other +planets, <a href="#page_105">105</a>. +</p> + +<p class="index"> +<b>Selenography</b> (<i>lunography</i>), a description of the moon's +surface. +</p> + +<p class="index"> +<b>Signs of the zodiac</b>, the twelve equal parts, of 30° each, +into which the zodiac is divided. +</p> + +<p class="index"> +<b>Solar system</b>, view of, <a href="#page_100">100</a>, <a +href="#page_177">177</a>. +</p> + +<p class="index"> +<b>Solstices</b>, 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. +</p> + +<p class="index"> +<b>Spectroscope</b>, <a href="#page_46">46</a>. +</p> + +<p class="index"> +<b>Spectrum of sun and metals</b>, <a href="#page_50">50</a>. +</p> + +<p class="index"> +<b>Stars</b>, chemistry of, <a href="#page_28">28</a>; distance +of, <a href="#page_70">70-73</a>; mode of naming, +<a href="#page_196">196</a>; number of, <a href="#page_210">210</a>; +double and multiple, <a href="#page_210">210</a>; colored, +<a href="#page_214">214</a>; clusters of, <a href="#page_215">215</a>; +variable, <a href="#page_220">220</a>; temporary, new, and lost, +<a href="#page_223">223</a>; movements of lateral, +<a href="#page_226">226</a>; in line of sight, +<a href="#page_269">269</a>. +</p> + +<p class="index"> +<b>Stationary points</b>, places in a planet's orbit at which it +has no motion among the stars. +</p> + +<p class="index"> +<a name="page_284"><span class="page">Page 284</span></a> +<b>Stellar system</b>, the, <a href="#page_195">195</a>. +</p> + +<p class="index"> +<b>Summary of recent discoveries</b>, <a href="#page_269">269</a>. +</p> + +<p class="index"> +<b>Sun</b>, fall of two meteoric bodies into, <a href="#page_19">19</a>; +light from contraction of, <a href="#page_20">20</a>; as seen from +planets, <a href="#page_79">79</a>; corona, <a href="#page_81">81</a>; +hydrogen flames of, <a href="#page_84">84</a>; condition of, <a +href="#page_89">89</a>; spots, <a href="#page_90">90</a>; experiments, +<a href="#page_95">95</a>; apparent path among the stars, +<a href="#page_111">111</a>; power of, <a href="#page_250">250</a>. +</p> + +<p class="index"> +<b>Symbols used in astronomy</b>, <a href="#page_275">275</a>. +</p> + +<p class="index"> +<b>Telescope</b>, refracting, <a href="#page_43">43</a>; reflecting, +<a href="#page_44">44</a>; Cambridge equatorial, +<a href="#page_46">46</a>. +</p> + +<p class="index"> +<b>Telescopic work</b>, clusters, <a href="#page_210">210</a>; double +stars, <a href="#page_212">212</a>. +</p> + +<p class="index"> +<b>Temporary stars</b>, <a href="#page_223">223</a>. +</p> + +<p class="index"> +<b>Terminator</b>, the boundary-line between light and darkness +on the moon or a planet. +</p> + +<p class="index"> +<b>Tides</b>, <a href="#page_146">146</a>. +</p> + +<p class="index"> +<b>Transit</b>, 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, <a +href="#page_65">65</a>. +</p> + +<p class="index"> +<b>Ultimate force</b>, the, <a href="#page_249">249</a>. +</p> + +<p class="index"> +<b>Uranus</b>, elements of, <a href="#page_173">173</a>; moons +of, retrograde, <a href="#page_174">174</a>; perturbed by Neptune, +<a href="#page_176">176</a>. +</p> + +<p class="index"> +<b>Variable stars</b>, <a href="#page_220">220</a>. +</p> + +<p class="index"> +<b>Venus</b>, <a href="#page_139">139</a>. +</p> + +<p class="index"> +<b>Vernier</b>, a scale to measure very minute distances. +</p> + +<p class="index"> +<b>Vertical circle</b>, 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. +</p> + +<p class="index"> +<b>Vulcan</b>, discovery of, <a href="#page_137">137</a>. +</p> + +<p class="index"> +<b>Worlds, the, and the Word</b>, teach the same truth, +<a href="#page_231">231-245</a>. +</p> + +<p class="index"> +<b>Year</b>, the, length of, on any planet, is determined by the +periodic time. +</p> + +<p class="index"> +<b>Zenith</b>, the point in the celestial sphere directly overhead. +</p> + +<p class="index"> +<b>Zodiac</b>, 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. +</p> + +<p class="index"> +<b>Zodiacal light</b>, <a href="#page_80">80</a>. +</p> + +<p class="title"> +<a name="page_285"><span class="page">Page 285</span></a> +TO FIND THE STARS IN THE SKY. +</p> + +<p class="indent"> +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. +</p> + +<div style="width: 498px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 498px; + font-size: smaller; text-align: justify; "> +<img src="images/back1.jpg" width="498" height="493" alt="Back plate 1"> +<br /> +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. +</span> +</div> + +<div style="width: 492px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 492px; + font-size: smaller; text-align: justify; "> +<img src="images/back2.jpg" width="492" height="347" alt="Back plate 2"> +<br /> +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. +</span> +</div> + +<div style="width: 490px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 490px; + font-size: smaller; text-align: justify; "> +<img src="images/back3.jpg" width="490" height="391" alt="Back plate 3"> +<br /> +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. +</span> +</div> + +<div style="width: 496px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 496px; + font-size: smaller; text-align: justify; "> +<img src="images/back4.jpg" width="496" height="443" alt="Back plate 4"> +<br /> +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. +</span> +</div> + +<div style="width: 498px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 498px; + font-size: smaller; text-align: justify; "> +<img src="images/back5.jpg" width="498" height="344" alt="Back plate 5"> +<br /> +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. +</span> +</div> + +<div style="width: 502px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 502px; + font-size: smaller; text-align: justify; "> +<img src="images/back6.jpg" width="502" height="436" alt="Back plate 6"> +<br /> +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. +</span> +</div> + +<div style="width: 494px; text-align: center; margin: 1em;"> +<span style="margin: 0px; width: 494px; + font-size: smaller; text-align: justify; "> +<img src="images/back7.jpg" width="494" height="344" alt="Back plate 7"> +<br /> +Fomalhaut comes to the Meridian, only 17° from the horizon, +at 8 o'clock November 4th. +</span> +</div> + + + + + + + + +<pre> + + + + + +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-h.htm or 15620-h.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. 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