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display: block; text-align: center;} -} - </style> - </head> - -<body> - - -<pre> - -Project Gutenberg's Pleasant Ways in Science, by Richard A. Proctor - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world 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. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - -Title: Pleasant Ways in Science - -Author: Richard A. Proctor - -Release Date: March 17, 2017 [EBook #54376] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK PLEASANT WAYS IN SCIENCE *** - - - - -Produced by Chris Curnow, Charlie Howard, and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - -</pre> - - -<div class="transnote covernote"> -<p class="center">Transcriber’s Note: -Cover created by Transcriber and placed in the Public Domain.</p> -</div> - -<h1>PLEASANT WAYS IN SCIENCE.</h1> - -<hr /> - -<h2>WORKS BY RICHARD A. PROCTOR.</h2> - -<blockquote class="hang narrow larger"> - -<p>LIGHT SCIENCE FOR LEISURE -HOURS: Familiar Essays on Scientific -Subjects. Crown 8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>THE ORBS AROUND US: A Series -of Essays on the Moon and Planets, -Meteors and Comets. With Charts and -Diagrams. Crown 8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>OTHER WORLDS THAN OURS: -The Plurality of Worlds Studied under -the Light of Recent Scientific Researches. -With 14 Illustrations. Crown -8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>OTHER SUNS THAN OURS: A -Series of Essays on Suns—Old, Young, -and Dead. With other Science Gleanings. -Two Essays on Whist, and Correspondence -with Sir John Herschel. With -9 Star Maps and Diagrams. Cr. 8vo, -3<i>s.</i> 6<i>d.</i></p> - -<p>THE MOON: Her Motions, Aspects, -Scenery, and Physical Condition. With -Plates, Charts, Woodcuts, &c. Crown -8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>UNIVERSE OF STARS: Presenting -Researches into and New Views respecting -the Constitution of the Heavens. -With 22 Charts and 22 Diagrams. 8vo, -10<i>s.</i> 6<i>d.</i></p> - -<p>LARGER STAR ATLAS for the -Library, in 12 Circular Maps, with Introduction -and 2 Index Pages. Folio, -15<i>s.</i>; or Maps only, 12<i>s.</i> 6<i>d.</i></p> - -<p>NEW STAR ATLAS for the Library, -the School, and the Observatory, in 12 -Circular Maps. Crown 8vo, 5<i>s.</i></p> - -<p>HALF-HOURS WITH THE -STARS: A Plain and Easy Guide to -the Knowledge of the Constellations. -Showing in 12 Maps the position of the -principal Star Groups night after night -throughout the Year. With Introduction -and a separate Explanation of each -Map. True for every Year. 4to, 3<i>s.</i> net.</p> - -<p>HALF-HOURS WITH THE TELESCOPE: -A Popular Guide to the Use -of the Telescope as a means of Amusement -and Instruction. With 7 Plates. -Fcp. 8vo, 2<i>s.</i> 6<i>d.</i></p> - -<p>THE STARS IN THEIR SEASONS: -An Easy Guide to a Knowledge of the -Star Groups, in 12 Large Maps. Imperial -8vo, 5<i>s.</i></p> - -<p>THE SOUTHERN SKIES: A Plain -and Easy Guide to the Constellations of -the Southern Hemisphere. Showing in -12 Maps the position of the principal -Star Groups night after night throughout -the Year. With an Introduction -and a separate Explanation of each -Map. True for every Year. 4to, 5<i>s.</i></p> - -<p>STAR PRIMER: Showing the Starry -Sky Week by Week, in 24 Hourly Maps. -Crown 4to, 2<i>s.</i> 6<i>d.</i></p> - -<p>ROUGH WAYS MADE SMOOTH: -Familiar Essays on Scientific Subjects. -Crown 8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>OUR PLACE AMONG INFINITIES: -A Series of Essays contrasting -our Little Abode in Space and Time -with the Infinities around us. Crown -8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>THE EXPANSE OF HEAVEN: -Essays on the Wonders of the Firmament. -Crown 8vo, 3s. 6<i>d.</i></p> - -<p>THE GREAT PYRAMID: OBSERVATORY, -TOMB, AND TEMPLE. -With Illustrations. Crown 8vo, 5<i>s.</i></p> - -<p>PLEASANT WAYS IN SCIENCE. -Crown 8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>MYTHS AND MARVELS OF ASTRONOMY. -Crown 8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>NATURE STUDIES. By <span class="smcap">Grant -Allen</span>, <span class="smcap">A. Wilson</span>, <span class="smcap">T. Foster</span>, <span class="smcap">E. -Clodd</span>, and <span class="smcap">R. A. Proctor</span>. Crown -8vo, 3<i>s.</i> 6<i>d.</i></p> - -<p>LEISURE READINGS. By <span class="smcap">E. -Clodd</span>, <span class="smcap">A. Wilson</span>, <span class="smcap">T. Foster</span>, <span class="smcap">A. C. -Ranyard</span>, and <span class="smcap">R. A. Proctor</span>. Crown -8vo, 5<i>s.</i> Cheap Edition, 3<i>s.</i> 6<i>d.</i></p> - -<p>STRENGTH: How to Get Strong -and Keep Strong. With Chapters on -Rowing and Swimming, Fat, Age, and -the Waist. With 9 Illustrations. Crown -8vo, 2<i>s.</i></p> - -<p>CHANCE AND LUCK: A Discussion -of the Laws of Luck, Coincidences, -Wagers, Lotteries, and the Fallacies of -Gambling, &c. Crown 8vo, 2<i>s.</i> 6<i>d.</i></p> - -<p>HOW TO PLAY WHIST: With the -Laws and Etiquette of Whist. Crown -8vo, 3<i>s.</i> net.</p> - -<p>HOME WHIST: An Easy Guide to -Correct Play. 16mo, 1<i>s.</i></p></blockquote> - -<hr class="short" /> -<p class="p0 larger center"><span class="smcap">London</span>: LONGMANS, GREEN, & CO.</p> - -<hr /> - -<p class="newpage p4 center vspace xxlarge gesperrt wspace"> -PLEASANT WAYS<br /> -<span class="smaller">IN SCIENCE</span></p> - -<p class="p2 center larger vspace"><span class="xsmall">BY</span><br /> -<span class="wspace gesperrt">RICHARD A. PROCTOR</span></p> - -<p class="p1 center small vspace">AUTHOR OF<br /> -“ROUGH WAYS MADE SMOOTH,” “THE EXPANSE OF HEAVEN,” “OUR PLACE<br /> -AMONG INFINITIES,” “MYTHS AND MARVELS OF ASTRONOMY,”<br /> -ETC. ETC.</p> - -<p class="p2 center"><i>NEW IMPRESSION</i></p> - -<p class="p2 center vspace wspace"><span class="gesperrt larger">LONGMANS, GREEN, AND CO.</span><br /> -39 PATERNOSTER ROW, LONDON<br /> -NEW YORK AND BOMBAY<br /> -1905 -</p> - -<hr /> - -<div class="chapter"> -<h2><a id="CONTENTS"></a>CONTENTS.</h2> -</div> - -<table id="toc" summary="Contents"> - <tr class="small"> - <td> </td> - <td class="tdr nopad">PAGE</td></tr> - <tr> - <td class="tdl"><span class="smcap">Oxygen in the Sun</span></td> - <td class="tdr"><a href="#OXYGEN_IN_THE_SUN">1</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Sun-Spot, Storm, and Famine</span></td> - <td class="tdr"><a href="#SUN-SPOT_STORM_AND_FAMINE">28</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">New Ways of Measuring the Sun’s Distance</span></td> - <td class="tdr"><a href="#NEW_WAYS_OF_MEASURING_THE_SUNS_DISTANCE">56</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Drifting Light Waves</span></td> - <td class="tdr"><a href="#DRIFTING_LIGHT-WAVES">77</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">The New Star which faded into Star-Mist</span></td> - <td class="tdr"><a href="#THE_NEW_STAR_WHICH_FADED_INTO_STAR-MIST">106</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Star-Grouping, Star-Drift, and Star-Mist</span></td> - <td class="tdr"><a href="#STAR-GROUPING_STAR-DRIFT_AND_STAR-MIST">136</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Mallet’s Theory of Volcanoes</span></td> - <td class="tdr"><a href="#MALLETS_THEORY_OF_VOLCANOES">151</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Towards the North Pole</span></td> - <td class="tdr"><a href="#TOWARDS_THE_NORTH_POLE">156</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">A Mighty Sea-Wave</span></td> - <td class="tdr"><a href="#A_MIGHTY_SEA-WAVE">178</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Strange Sea Creatures</span></td> - <td class="tdr"><a href="#STRANGE_SEA_CREATURES">199</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">On some Marvels in Telegraphy</span></td> - <td class="tdr"><a href="#ON_SOME_MARVELS_IN_TELEGRAPHY">232</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">The Phonograph, or Voice-Recorder</span></td> - <td class="tdr"><a href="#THE_PHONOGRAPH_OR_VOICE-RECORDER">274</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">The Gorilla and other Apes</span></td> - <td class="tdr"><a href="#THE_GORILLA_AND_OTHER_APES">296</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">The Use and Abuse of Food</span></td> - <td class="tdr"><a href="#THE_USE_AND_ABUSE_OF_FOOD">330</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Ozone</span></td> - <td class="tdr"><a href="#OZONE">347</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Dew</span></td> - <td class="tdr"><a href="#DEW">357</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">The Levelling Power of Rain</span></td> - <td class="tdr"><a href="#THE_LEVELLING_POWER_OF_RAIN">367</a></td></tr> - <tr> - <td class="tdl"><span class="smcap">Ancient Babylonian Astrogony</span></td> - <td class="tdr"><a href="#ANCIENT_BABYLONIAN_ASTROGONY">388</a></td></tr> -</table> - -<hr /> - -<p><span class="pagenum"><a id="Page_vii">vii</a></span></p> - -<div class="chapter"> -<h2><a id="PREFACE"></a>PREFACE.</h2> -</div> - -<p class="in0">It is very necessary that all who desire to become -really proficient in any department of science should -follow the beaten track, toiling more or less painfully -over the difficult parts of the high road which -is their only trustworthy approach to the learning -they desire to attain. But there are many who -wish to learn about scientific discoveries without this -special labour, for which some have, perhaps, little -taste, while many have scant leisure. My purpose -in the present work, as in my “Light Science for -Leisure Hours,” the “Myths and Marvels of Astronomy,” -the “Borderland of Science,” and “Science -Byways,” has been to provide paths of easy access -to the knowledge of some of the more interesting -discoveries, researches, or inquiries of the science of -the day. I wish it to be distinctly understood that -my purpose is to interest rather than to instruct, in -the strict sense of the word. But I may add that it -seems to me even more necessary to be cautious, and -accurate in such a work as the present than in -advanced treatises. For in a scientific work the -reasoning which accompanies the statements of fact<span class="pagenum"><a id="Page_viii">viii</a></span> -affords the means of testing and sometimes of correcting -such statements. In a work like the present, -where explanation and description take the place of -reasoning, there is no such check. For this reason I -have been very careful in the accounts which I have -given of the subjects here dealt with. I have been -particularly careful not to present, as established -truths, such views as are at present only matters -of opinion.</p> - -<p>The essays in the present volume are taken chiefly -from the <cite>Contemporary Review</cite>, the <cite>Gentleman’s Magazine</cite>, -the <cite>Cornhill Magazine</cite>, <cite>Belgravia</cite>, and <cite>Chambers’ -Journal</cite>. The sixth, however, presents the substance -(and official report) of a lecture which I delivered -at the Royal Institution in May, 1870. It was then -that I first publicly enunciated the views respecting -the stellar universe which I afterwards more fully -stated in my “Universe of Stars.” The same views -have also been submitted to the Paris Academy of -Science, as the results of his own investigations, by -M. Flammarion, in words which read almost like -translations of passages in the above-mentioned -essay.</p> - -<p class="sigright"> -RICHARD A. PROCTOR. -</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_1">1</a></span></p> - -<div class="chapter"> -<h2><span class="larger wspace"><a id="PLEASANT_WAYS_IN_SCIENCE"></a>PLEASANT WAYS IN SCIENCE.</span></h2> -</div> - -<h2 class="nobreak p4"><a id="OXYGEN_IN_THE_SUN"></a><i>OXYGEN IN THE SUN.</i></h2> - -<p class="in0">The most promising result of solar research since Kirchhoff -in 1859 interpreted the dark lines of the sun’s spectrum -has recently been announced from America. Interesting -in itself, the discovery just made is doubly interesting in -what it seems to promise in the future. Just as Kirchhoff’s -great discovery, that a certain double dark line in the solar -spectrum is due to the vapour of sodium in the sun’s atmosphere, -was but the first of a long series of results which the -spectroscopic analysis of the sun was to reveal, so the discovery -just announced that a certain important gas—the -oxygen present in our air and the chief chemical constituent -of water—shows its presence in the sun by bright -lines instead of dark, will in all probability turn out to be -but the firstfruits of a new method of examining the solar -spectrum. As its author, Dr. Henry Draper, of New York, -remarks, further investigation in the direction he has pursued -will lead to the discovery of other elements in the sun, but -it was not “proper to conceal, for the sake of personal -advantage, the principle on which such researches are to -be conducted.” It may well happen, though I anticipate -otherwise, that by thus at once describing his method of -observation, Dr. Draper may enable others to add to the<span class="pagenum"><a id="Page_2">2</a></span> -list of known solar elements some which yet remain to be -detected; but if Dr. Draper should thus have added but -one element to that list, he will ever be regarded as the -physicist to whose acumen the method was due by which all -were detected, and to whom, therefore, the chief credit of -their discovery must certainly be attributed.</p> - -<p>I propose briefly to consider the circumstances which -preceded the great discovery which it is now my pleasing -duty to describe, in order that the reader may the more -readily follow the remarks by which I shall endeavour to -indicate some of the results which seem to follow from the -discovery, as well as the line along which, in my opinion, -the new method may most hopefully be followed.</p> - -<p>It is generally known that what is called the spectroscopic -method of analyzing the sun’s substance had its origin -in Kirchhoff’s interpretation of the dark lines in the solar -spectrum. Until 1859 these dark lines had not been -supposed to have any special significance, or rather it had -not been supposed that their significance, whatever it might -be, could be interpreted. A physicist of some eminence -spoke of these phenomena in 1858 in a tone which ought -by the way seldom to be adopted by the man of science. -“The phenomena defy, as we have seen,” he said, “all -attempts hitherto to reduce them within empirical laws, and -no complete explanation or theory of them is possible. -All that theory can be expected to do is this—it may explain -how dark lines of any sort may arise within the spectrum.” -Kirchhoff, in 1859, showed not only how dark lines of any -sort may appear, but how and why they do appear, and -precisely what they mean. He found that the dark lines -of the solar spectrum are due to the vapours of various -elements in the sun’s atmosphere, and that the nature of -such elements may be determined from the observed position -of the dark lines. Thus when iron is raised by the -passage of the electric spark to so intense a degree of heat -that it is vaporized, the light of the glowing vapour of iron -is found to give a multitude of bright lines along the whole<span class="pagenum"><a id="Page_3">3</a></span> -length of the spectrum—that is, some red, some orange, -some yellow, and so on. In the solar spectrum corresponding -dark lines are found along the whole length of the -spectrum—that is, some in the red, some in the orange, -yellow, etc., and precisely in those parts of these various -spectral regions which the bright lines of glowing iron would -occupy. Multitudes of other dark lines exist of course in -the solar spectrum. But those corresponding to the bright -lines of glowing iron are unquestionably there. They are -by no means lost in the multitude, as might be expected; -but, owing to the peculiarity of their arrangement, strength, -etc., they are perfectly recognizable as the iron lines reversed, -that is, dark instead of bright. Kirchhoff’s researches -showed how this is to be interpreted. It means that the -vapour of iron exists in the atmosphere of the sun, glowing -necessarily with an intensely bright light; <em>but</em>, being cooler -(however intensely hot) than the general mass of the sun -within, the iron vapour absorbs more light than it emits, -and the result is that the iron lines, instead of appearing -bright, as they would if the iron vapour alone were shining, -appear relatively dark on the bright rainbow-tinted background -of the solar spectrum.</p> - -<p>Thus was it shown that in the atmosphere of the sun -there is the glowing vapour of the familiar metal, iron; and -in like manner other metals, and one element (hydrogen) -which is not ordinarily regarded as a metal, were shown to -be present in the sun’s atmosphere. In saying that they -are present in the sun’s atmosphere, I am, in point of fact, -saying that they are present in the sun; for the solar atmosphere -is, in fact, the outer part of the sun himself, since a -very large part, if not by far the greater part, of the sun’s -mass must be vaporous. But no other elements, except the -metals iron, sodium, barium, calcium, magnesium, aluminium, -manganese, chromium, cobalt, nickel, zinc, copper, -and titanium, and the element hydrogen, were shown to be -present in the sun, by this method of observing directly the -solar dark lines. In passing, I may note that there are<span class="pagenum"><a id="Page_4">4</a></span> -reasons for regarding hydrogen as a metallic element, strange -though the idea may seem to those who regard hardness, -brightness, malleability, ductility, plasticity, and the like, -as the characteristic properties of metals, and necessarily -fail to comprehend how a gas far rarer, under the same -conditions, than the air we breathe, and which cannot -possibly be malleable, ductile, or the like, can conceivably -be regarded as a metal. But there is in reality no necessary -connection between any one of the above properties and -the metallic nature; many of the fifty-five metals are wanting -in all of these properties; nor is there any reason why, as -we have in mercury a metal which at ordinary temperatures -is a liquid, so we might have in hydrogen a metal -which, at all obtainable temperatures, and under all obtainable -conditions of pressure, is gaseous. It was shown by -the late Professor Graham (aided in his researches most -effectively by Dr. Chandler Roberts) that hydrogen will -enter into such combination with the metal palladium that -it may be regarded as forming, for the time, with the palladium, -an alloy; and as alloys can only be regarded as -compounds of two or more metals, the inference is that -hydrogen is in reality a metallic element.</p> - -<p>Fourteen only of the elements known to us, or less than -a quarter of the total number, were thus found to be present -in the sun’s constitution; and of these all were metals, if -we regard hydrogen as metallic. Neither gold nor silver -shows any trace of its presence, nor can any sign be seen -of platinum, lead, and mercury. But, most remarkable of -all, and most perplexing, was the absence of all trace of -oxygen and nitrogen, two gases which could not be supposed -wanting in the substance of the great ruling centre of the -planetary system. It might well be believed, indeed, that -none of the five metals just named are absent from the sun, -and indeed that every one of the forty metals not recognized -by the spectroscopic method nevertheless exists in the sun. -For according to the nebular hypothesis of the origin of our -solar system, the sun might be expected to contain all the<span class="pagenum"><a id="Page_5">5</a></span> -elements which exist in our earth. Some of these elements -might indeed escape discovery, because existing only in -small quantities; and others (as platinum, gold, and lead, -for example), because but a small portion of their vaporous -substance rose above the level of that glowing surface which -is called the photosphere. But that oxygen, which constitutes -so large a portion of the solid, liquid, and vaporous -mass of our earth, should not exist in enormous quantities, -and its presence be very readily discernable, seemed amazing -indeed. Nitrogen, also, might well be expected to be -recognizable in the sun. Carbon, again, is so important a -constituent of the earth, that we should expect to discover -clear traces of its existence in the sun. In less degree, -similar considerations apply to sulphur, boron, silicon, and -the other non-metallic elements.</p> - -<p>It was not supposed, however, by any one at all competent -to form an opinion on the subject, that oxygen, nitrogen, -and carbon are absent from the sun. It was perceived -that an element might exist in enormous quantities in the -substance of the sun, and yet fail to give any evidence of its -presence, or only give such evidence as might readily escape -recognition. If we remember how the dark lines are really -caused, we shall perceive that this is so. A glowing vapour -in the atmosphere of the sun absorbs rays of the same colour -as it emits. If then, it is cooler than the glowing mass of -the sun which it enwraps, and if, notwithstanding the heat -received from this mass, it remains cooler, then it suffers -none of those rays to pass earthwards.<a id="FNanchor_1" href="#Footnote_1" class="fnanchor">1</a> It emits rays of the -same kind (that is, of the same <em>colour</em>) itself, but, being cooler, -the rays thus coming from it are feebler; or, to speak more<span class="pagenum"><a id="Page_6">6</a></span> -correctly, the ethereal waves thus originated are feebler than -those of the same order which <em>would</em> have travelled earthwards -from the sun but for the interposed screen of vapour. -Hence the corresponding parts of the solar spectrum are less -brilliant, and contrasted with the rainbow-tinted streak of -light, on which they lie as on a background, they appear dark.</p> - -<p>In order, then, that any element may be detected by its -dark lines, it is necessary that it should lie as a vaporous -screen between the more intensely heated mass of the sun -and the eye of the observer on earth. It must then form an -enclosing envelope cooler than the sun within it. Or rather, -some part of the vapour must be thus situated. For enormous -masses of the vapour might be within the photospheric -surface of the sun at a much higher temperature, which yet, -being enclosed in the cooler vaporous shell of the same -substance, would not be able to send its light rays earthwards. -One may compare the state of things, so far as that particular -element is concerned, to what is presented in the case of -a metallic globe cooled on the outside but intensely hot -within. The cool outside of such a globe is what determines -the light and heat received from it, so long as the more -heated mass within has not yet (by conduction) warmed the -exterior shell. So in the case of a vapour permeating the -entire mass, perhaps, of the sun, and at as high a temperature -as the sun everywhere except on the outside: it is the -temperature of the outermost part of such a vaporous mass -which determines the intensity of the rays received from it—or -in other words, determines whether the corresponding -parts of the spectrum shall be darker or not than the rest of -the spectrum. If the vapour does not rise above the photosphere -of the sun in sufficient quantity to exercise a recognizable -absorptive effect, its presence in the sun will not be -indicated by any dark lines.</p> - -<p>I dwell here on the question of quantity, which is sometimes -overlooked in considering the spectroscopic evidence -of the sun’s condition, but is in reality a very important -factor in determining the nature of the evidence relating to<span class="pagenum"><a id="Page_7">7</a></span> -each element in the solar mass. In some cases, the quantity -of a material necessary to give unmistakable spectroscopic -evidence is singularly small; insomuch that new elements, -as thallium, cæsium, rubidium, and gallium, have been actually -first recognized by their spectral lines when existing in -such minute quantities in the substances examined as to give -no other trace whatever of their existence. But it would be -altogether a mistake to suppose that some element existing -in exceedingly small quantities, or, more correctly, existing in -the form of an exceedingly rare vapour in the sun’s atmosphere, -would be detected by means of its dark lines, or <em>by any other -method depending on the study of the solar spectrum</em>. When we -place a small portion of some substance in the space between -the carbon points of an electric lamp, and volatilize that -substance in the voltaic arc, we obtain a spectrum including -all the bright lines of the various elements contained in the -substance; and if some element is contained in it in exceedingly -small quantity, we may yet perceive its distinctive -bright lines among the others (many of them far brighter) -belonging to the elements present in greater quantities. But -if we have (for example) a great mass of molten iron, the -rainbow-tinted spectrum of whose light we examine from a -great distance, and if a small quantity of sodium, or other substance -which vaporizes at moderate temperatures, be cast into -the molten iron so that the vapour of the added element -presently rises above the glowing surface of the iron, no trace -of the presence of this vapour would be shown in the spectrum -observed from a distance. The part of the spectrum -where the dark lines of sodium usually appear would, undoubtedly, -be less brilliant than before, in the same sense -that the sun may be said to be less brilliant when the air is -in the least degree moist than when it is perfectly dry; but -the loss of brilliancy is as utterly imperceptible in the one -case as it is in the other. In like manner, a vapour might -exist in the atmosphere of the sun (above the photosphere, -that is), of whose presence not a trace would be afforded in -the spectroscope, for the simple reason that the absorptive<span class="pagenum"><a id="Page_8">8</a></span> -action of the vapour, though exerted to reduce the brightness -of particular solar rays or tints, would not affect those rays -sufficiently for the spectroscopist to recognize any diminution -of their lustre.</p> - -<p>There is another consideration, which, so far as I know, -has not hitherto received much attention, but should certainly -be taken into account in the attempt to interpret the -real meaning of the solar spectrum. Some of the metals -which are vaporized by the sun’s heat below the photosphere -may become liquid or even solid at or near the level of the -photosphere. Even though the heat at the level of the -photosphere may be such that, under ordinary conditions of -pressure and so forth, such metals would be vaporous, the -enormous pressure which must exist not far below the level -of the photosphere may make the heat necessary for complete -vaporization far greater than the actual heat at that -level. In that case the vapour will in part condense into -liquid globules, or, if the heat is considerably less than is -necessary to keep the substance in the form of vapour, then -it may in part be solidified, the tiny globules of liquid metal -becoming tiny crystals of solid metal. We see both conditions -fulfilled within the limits of our own air in the case of -the vapour of water. Low down the water is present in the -air (ordinarily) in the form of pure vapour; at a higher level -the vapour is condensed by cold into liquid drops forming -visible clouds (cumulus clouds), and yet higher, where the -cold is still greater, the minute water-drops turn into ice-crystals, -forming those light fleecy clouds called cirrus clouds -by the meteorologist. Now true clouds of either sort may -exist in the solar atmosphere even above that photospheric -level which forms the boundary of the sun we see. It may -be said that the spectroscope, applied to examine matter -outside the photosphere, has given evidence only of vaporous -cloud masses. The ruddy prominences which tower tens of -thousands of miles above the surface of the sun, and the sierra -(or as it is sometimes unclassically called, the chromosphere) -which covers usually the whole of the photosphere to a<span class="pagenum"><a id="Page_9">9</a></span> -depth of about eight thousand miles, show only, under spectroscopic -scrutiny, the bright lines indicating gaseity. But -though this is perfectly true, it is also true that we have not -here a particle of evidence to show that clouds of liquid -particles, and of tiny crystals, may not float over the sun’s -surface, or even that the ruddy clouds shown by the spectroscope -to shine with light indicative of gaseity may not also -contain liquid and crystalline particles. For in point of fact, -the very principle on which our recognition of the bright -lines depends involves the inference that matter whose light -would <em>not</em> be resolved into bright lines would not be recognizable -at all. The bright lines are seen, because by means -of a spectroscope we can throw them far apart, without -reducing their lustre, while the background of rainbow-tinted -spectrum has its various portions similarly thrown further -apart and correspondingly weakened. One may compare -the process (the comparison, I believe, has not hitherto been -employed) to the dilution of a dense liquid in which solid -masses have been floating: the more we increase the quantity -of the liquid in diluting it with water, the more transparent -it becomes, but the solid masses in it are not changed, -so that we only have to dilute the liquid sufficiently to see -these masses. <em>But</em> if there were in the interstices of the -solid masses particles of some substance which dissolved in -the water, we should not recognize the presence of this substance -by any increase in its visibility; for the very same -process which thinned the liquid would thin this soluble -substance in the same degree. In like manner, by dispersing -and correspondingly weakening the sun’s light more and -more, we can recognize the light of the gaseous matter in the -prominences, for this is not weakened; but if the prominences -also contain matter in the solid or liquid form (that is, drops -or crystals), the spectroscopic method will not indicate the -presence of such matter, for the spectrum of matter of this -sort will be weakened by dispersion in precisely the same -degree that the solar spectrum itself is weakened.</p> - -<p>It is easy to see how the evidence of the presence of any<span class="pagenum"><a id="Page_10">10</a></span> -element which behaved in this way would be weakened, if -we consider what would happen in the case of our own -earth, according as the air were simply moist but without -clouds, or loaded with cumulus masses but without cirrus -clouds, or loaded with cirrus clouds. For although there is -not in the case of the earth a central glowing mass like the -sun’s, on whose rainbow-tinted spectrum the dark lines -caused by the absorptive action of our atmosphere could -be seen by the inhabitant of some distant planet studying -the earth from without, yet the sun’s light reflected from -the surface of the earth plays in reality a similar part. -It does not give a simple rainbow-tinted spectrum; for, being -sunlight, it shows all the dark lines of the solar spectrum: -but the addition of new dark lines to these, in consequence -of the absorptive action of the earth’s atmosphere, could -very readily be determined. In fact, we do thus recognize -in the spectra of Mars, Venus, and other planets, the -presence of aqueous vapour in their atmosphere, despite -the fact that our own air, containing also aqueous vapour, -naturally renders so much the more difficult the detection -of that vapour in the atmosphere of remote planets necessarily -seen through our own air. Now, a distant observer -examining the light of our own earth on a day when, though -the air was moist, there were no clouds, would have ample -evidence of the presence of the vapour of water; for the -light which he examined would have gone twice through our -earth’s atmosphere, from its outermost thinnest parts to the -densest layers close to the surface, then back again through -the entire thickness of the air. But if the air were heavily -laden with cumulus clouds (without any cirrus clouds at -a higher layer), although <em>we</em> should know that there was -abundant moisture in the air, and indeed much more moisture -then there had been when there had been no clouds, our -imagined observer would either perceive no traces at all of -this moisture, or he would perceive traces so much fainter -than when the air was clear that he would be apt to infer that -the air was either quite dry, or at least very much drier than<span class="pagenum"><a id="Page_11">11</a></span> -it had been in that case. For the light which he would -receive from the earth would not in this case have passed -through the entire depth of moisture-laden air twice, but -twice only through that portion of the air which lay above -the clouds, at whose surface the sun’s light would be reflected. -The whole of the moisture-laden layer of the air would be -snugly concealed under the cloud-layer, and would exercise -no absorptive action whatever on the light which the remote -observer would examine. If from the upper surface of the -layer of cumulus clouds aqueous vapour rose still higher, -and were converted in the cold upper regions of the -atmosphere into clouds of ice-crystals, the distant observer -would have still less chance of recognizing the presence of -moisture in our atmosphere. For the layer of air between -the cumulus clouds and the cirrus clouds would be unable to -exert any absorptive action on the light which reached the -observer. All such light would come to him after reflection -from the layer of cirrus clouds. He would be apt to infer -that there was no moisture at all in the air of our planet, at -the very time when in fact there was so much moisture that -not one layer only, but two layers of clouds enveloped the -earth, the innermost layer consisting of particles of liquid -water, the outermost of particles of frozen water. Using the -words ice, water, and steam, to represent the solid, liquid, -and vaporous states of water, we may fairly say that ice and -water, by hiding steam, would persuade the remote observer -that there was no water at all on the earth—at least if he -trusted solely to the spectroscopic evidence then obtained.<a id="FNanchor_2" href="#Footnote_2" class="fnanchor">2</a></p> - -<p><span class="pagenum"><a id="Page_12">12</a></span> -We might in like manner fail to obtain any spectroscopic -evidence of the presence of particular elements in the -sun, because they do not exist in sufficient quantity in the -vaporous form in those outer layers which the spectroscope -can alone deal with.</p> - -<p>In passing, I must note a circumstance in which some of -those who have dealt with this special part of the spectroscopic -evidence have erred. It is true in one sense that -some elements may be of such a nature that their vapours -cannot rise so high in the solar atmosphere as those of -other elements. But it must not be supposed that the -denser vapours seek a lower level, the lighter vapours -rising higher. According to the known laws of gaseous -diffusion, a gas or vapour diffuses itself throughout a space -occupied by another gas or several other gases, in the same -way as though the space were not occupied at all. If we -introduce into a vessel full of common air a quantity of -carbonic acid gas (I follow the older and more familiar -nomenclature), this gas, although of much higher specific -gravity than either oxygen or nitrogen, does not take its -place at the bottom of the vessel, but so diffuses itself that -the air of the upper part of the vessel contains exactly the -same quantity of carbonic acid gas as the air of the lower<span class="pagenum"><a id="Page_13">13</a></span> -part. Similarly, if hydrogen is introduced, it does not seek -the upper part of the vessel, but diffuses itself uniformly -throughout the vessel. If we enclose the carbonic acid gas -in a light silken covering, and the hydrogen in another (at -the same pressure as the air in the vessel) one little balloon -will sink and the other will rise; but this is simply because -diffusion is prevented. It may be asked how this agrees -with what I have said above, that some elements may not -exist in sufficient quantity or in suitable condition above the -sun’s photospheric level to give any spectroscope evidence -of their nature. As to quantity, indeed, the answer is -obvious: if there is only a small quantity of any given element -in the entire mass of the sun, only a very small quantity can -under any circumstances exist outside the photosphere. As -regards condition, it must be remembered that the vessel of -my illustrative case was supposed to contain air at a given -temperature and pressure throughout. If the vessel was so -large that in different parts of it the temperature and pressure -were different, the diffusion would, indeed, still be perfect, -because at all ordinary temperatures and pressures hydrogen -and carbonic acid gas remain gaseous. But if the vapour -introduced is of such a nature that at moderate temperatures -and pressures it condenses, wholly or in part, or liquefies, -the diffusion will not take place with the same uniformity. -We need not go further for illustration than to the case of -our own atmosphere as it actually exists. The vapour of -water spreads uniformly through each layer of the atmosphere -which is at such a temperature and pressure as to -permit of such diffusion; but where the temperature is too -low for complete diffusion (at the actual pressure) the -aqueous vapour is condensed into visible cloud, diffusion -being checked at this point as at an impassable boundary. -In the case of the sun, as in the case of our own earth, it is -not the density of an element when in a vaporous form -which limits its diffusion, but the value of the temperature -at which its vapour at given pressure condenses into liquid -particles. It is in this way only that any separation can be<span class="pagenum"><a id="Page_14">14</a></span> -effected between the various elements which exist in the -sun’s substance. A separation of this sort is unquestionably -competent to modify the spectroscopic evidence respecting -different elements. But it would be a mistake to -suppose that any such separation could occur as has been -imagined by some—a separation causing in remote times the -planets supposed to have been thrown off by the sun to be -rarest on the outskirts of the solar system and densest close -to the sun. The small densities of the outer family of -planets, as compared with the densities of the so-called -terrestrial planets, must certainly be otherwise explained.</p> - -<p>But undoubtedly the chief circumstance likely to operate -in veiling the existence of important constituents of the -solar mass must be that which has so long prevented spectroscopists -from detecting the presence of oxygen in the -sun. An element may exist in such a condition, either over -particular parts of the photosphere, or over the entire surface -of the sun, that instead of causing dark lines in the -solar spectrum it may produce bright lines. Such lines may -be conspicuous, or they may be so little brighter than the -background of the spectrum as to be scarcely perceptible -or quite imperceptible.</p> - -<p>In passing, I would notice that this interpretation of the -want of all spectroscopic evidence of the presence of oxygen, -carbon, and other elements in the sun, is not an <i xml:lang="la" lang="la">ex post -facto</i> explanation. As will presently appear, it is now absolutely -certain that oxygen, though really existing, and -doubtless, in enormous quantities, in the sun, has been concealed -from recognition in this way. But that this might -be so was perceived long ago. I myself, in the first edition -of my treatise on “The Sun,” pointed out, in 1870, with -special reference to nitrogen and oxygen, that an element -“may be in a condition enabling it to radiate as much light -as it absorbs, or else very little more or very little less; so -that it either obliterates all signs of its existence, or else -gives lines so little brighter or darker than the surrounding -parts of the spectrum that we can detect no trace of its<span class="pagenum"><a id="Page_15">15</a></span> -existence.” I had still earlier given a similar explanation -of the absence of all spectroscopic evidence of hydrogen in -the case of the bright star Betelgeux.<a id="FNanchor_3" href="#Footnote_3" class="fnanchor">3</a></p> - -<p>Let us more closely consider the significance of what we -learn from the spectral evidence respecting the gas hydrogen. -We know that when the total light of the sun is dealt -with, the presence of hydrogen is constantly indicated by -dark lines. In other words, regarding the sun as a whole, -hydrogen constantly reduces the emission of rays of those -special tints which correspond to the light of this element. -When we examine the light of other suns than ours, we find -that in many cases, probably in by far the greater number -of cases, hydrogen acts a similar part. But not in every -case. In the spectra of some stars, notably in those of -Betelgeux and Alpha Herculis, the lines of hydrogen are -not visible at all; while in yet others, as Gamma Cassiopeiæ, -the middle star of the five which form the straggling -W of this constellation, the lines of hydrogen show bright -upon the relatively dark background of the spectrum. When -we examine closely the sun himself, we find that although -his light as a whole gives a spectrum in which the lines of -hydrogen appear dark, the light of particular parts of his -surface, if separately examined, occasionally shows the -hydrogen lines bright as in the spectrum of Gamma Cassiopeiæ, -while sometimes the light of particular parts gives,<span class="pagenum"><a id="Page_16">16</a></span> -like the light of Betelgeux, no spectroscopic evidence whatever -of the presence of hydrogen. Manifestly, if the whole -surface of the sun were in the condition of the portions -which give bright hydrogen lines, the spectrum of the sun -would resemble that of Gamma Cassiopeiæ; while if the -whole surface were in the condition of those parts which -show no lines of hydrogen, the spectrum of the sun would -resemble that of Betelgeux. Now if there were any reason -for supposing that the parts of the sun which give no lines -of hydrogen are those from which the hydrogen has been -temporarily removed in some way, we might reasonably -infer that in the stars whose spectra show no hydrogen lines -there is no hydrogen. But the fact that the hydrogen lines -are sometimes seen bright renders this supposition untenable. -For we cannot suppose that the lines of hydrogen -change from dark to bright or from bright to dark (both -which changes certainly take place) without passing through -a stage in which they are neither bright nor dark; in other -words, we are compelled to assume that there is an intermediate -condition in which the hydrogen lines, though -really existent, are invisible because they are of precisely -the same lustre as the adjacent parts of the spectrum. -Hence the evanescence of the hydrogen lines affords no -reason for supposing that hydrogen has become even reduced -in quantity where the lines are not seen. And therefore -it follows that the invisibility of the hydrogen lines in -the spectrum of Betelgeux is no proof that hydrogen does -not exist in that star in quantities resembling those in which -it is present in the sun. And this, being demonstrated in -the case of one gas, must be regarded as at least probable -in the case of other gases. Wherefore the absence of the -lines of oxygen from the spectrum of any star affords no -sufficient reason for believing that oxygen is not present in -that star, or that it may not be as plentifully present as -hydrogen, or even far more plentifully present.</p> - -<p>There are other considerations which have to be taken -into account, as well in dealing with the difficulty arising<span class="pagenum"><a id="Page_17">17</a></span> -from the absence of the lines of particular elements from -the solar spectrum as in weighing the extremely important -discovery which has just been effected by Dr. H. Draper.</p> - -<p>I would specially call attention now to a point which I -thus presented seven years ago:—“The great difficulty of -interpreting the results of the spectroscopic analysis of the -sun arises from the circumstance that we have no means of -learning whence that part of the light comes which gives -the continuous spectrum. When we recognize certain dark -lines, we know certainly that the corresponding element -exists in the gaseous form at a lower temperature than the -substance which gives the continuous spectrum. But as -regards that continuous spectrum itself we can form no such -exact opinion.” It might, for instance, have its origin in -glowing liquid or solid matter; but it might also be compounded -of many spectra, each containing a large number -of bands, the bands of one spectrum filling up the spaces -which would be left dark between the bands of another -spectrum, and so on until the entire range from the extreme -visible red to the extreme visible violet were occupied by -what appeared as a continuous rainbow-tinted streak. “We -have, in fact, in the sun,” as I pointed out, “a vast agglomeration -of elements, subject to two giant influences, producing -in some sort opposing effects—viz., a temperature -far surpassing any we can form any conception of, and a -pressure (throughout nearly the whole of the sun’s globe) -which is perhaps even more disproportionate to the phenomena -of our experience. Each known element would -be vaporized by the solar temperature at known pressures; -each (there can be little question) would be solidified by the -vast pressures, did these arise at known temperatures. Now -whether, under these circumstances, the laws of gaseous -diffusion prevail where the elements <em>are</em> gaseous in the solar -globe; whether, where liquid matter exists it is in general -bounded in a definite manner from the neighbouring gaseous -matter; whether any elements at all are solid, and if so -under what conditions their solidity is maintained and the<span class="pagenum"><a id="Page_18">18</a></span> -limits of the solid matter defined—all these are questions -which <em>must</em> be answered before we can form a satisfactory -idea of the solar constitution; yet they are questions which -we have at present no means of answering.” Again, we -require to know whether any process resembling combustion -can under any circumstances take place in the sun’s globe. -If we could assume that some general resemblance exists -between the processes at work upon the sun and those we -are acquainted with, we might imagine that the various elements -ordinarily exist in the sun’s globe in the gaseous form -(chiefly) to certain levels, to others chiefly in the liquid -form, and to yet others chiefly in the solid form. But even -then that part of each element which is gaseous may exist -in two forms, having widely different spectra (in reality in -five, but I consider only the extreme forms). The light -of one part is capable of giving characteristic spectra of -lines or bands (which will be different according to pressure -and may appear either dark or bright); that of the other -is capable of giving a spectrum nearly or quite continuous.</p> - -<p>It will be seen that Dr. H. Draper’s discovery supplies -an answer to one of the questions, or rather to one of the -sets of questions, thus indicated. I give his discovery as -far as possible in his own words.</p> - -<p>“<em>Oxygen discloses itself</em>,” he says, “<em>by bright lines or -bands in the solar spectrum</em>, and does not give dark absorption-lines -like the metals. We must therefore change our -theory of the solar spectrum, and no longer regard it merely -as a continuous spectrum with certain rays absorbed by a -layer of ignited metallic vapours, but as having also bright -lines and bands superposed on the background of continuous -spectrum. Such a conception not only opens the way -to the discovery of others of the non-metals, sulphur, phosphorus, -selenium, chlorine, bromine, iodine, fluorine, carbon, -etc., but also may account for some of the so-called dark -lines, by regarding them as intervals between bright lines. -It must be distinctly understood that in speaking of the -solar spectrum here, I do not mean the spectrum of any<span class="pagenum"><a id="Page_19">19</a></span> -limited area upon the disc or margin of the sun, but the -spectrum of light from the whole disc.”</p> - -<p>In support of the important statement here advanced, -Dr. Draper submits a photograph of part of the solar spectrum -with a comparison spectrum of air, and also with some -of the lines of iron and aluminium. The photograph itself, -a copy of which, kindly sent to me by Dr. Draper, lies before -me as I write, fully bears out Dr. Draper’s statement. It is -absolutely free from handwork or retouching, except that -reference letters have been added in the negative. It shows -the part of the solar spectrum between the well-known -Fraunhofer lines G and H, of which G (an iron line) lies in -the indigo, and H (a line of hydrogen) in the violet, so that -the portion photographed belongs to that region of the -spectrum whose chemical or actinic energy is strongest. -Adjacent to this lies the photograph of the air lines, showing -nine or ten well-defined oxygen lines or groups of lines, and -two nitrogen bands. The exact agreement of the two -spectra in position is indicated by the coincidence of bright -lines of iron and aluminium included in the air spectrum -with the dark lines of the same elements in the solar spectrum. -“No close observation,” as Dr. Draper truly remarks, -“is needed to demonstrate to even the most casual observer” -(of this photograph) “that the oxygen lines are found in the -sun as bright lines.” There is in particular one quadruple -group of oxygen lines in the air spectrum, the coincidence -of which with a group of bright lines in the solar spectrum -is unmistakable.</p> - -<p>“This oxygen group alone is almost sufficient,” says Dr. -Draper, “to prove the presence of oxygen in the sun, for not -only does each of the four components have a representative -in the solar group, but the relative strength and the general -aspect of the lines in each case is similar.<a id="FNanchor_4" href="#Footnote_4" class="fnanchor">4</a> I shall not<span class="pagenum"><a id="Page_20">20</a></span> -attempt at this time,” he proceeds, “to give a complete list -of the oxygen lines, ... and it will be noticed that some -lines in the air spectrum which have bright anologues in the -sun are not marked with the symbol of oxygen. This is -because there has not yet been an opportunity to make the -necessary detailed comparisons. In order to be certain that -a line belongs to oxygen, I have compared, under various -pressures, the spectra of air, oxygen, nitrogen, carbonic acid, -carburetted hydrogen, hydrogen, and cyanogen.</p> - -<p>“As to the spectrum of nitrogen and the existence of -this element in the sun there is not yet certainty. Nevertheless, -even by comparing the diffused nitrogen lines of this -particular photograph, in which nitrogen has been sacrificed -to get the best effect for oxygen, the character of the evidence -appears. There is a triple band somewhat diffused in the -photograph belonging to nitrogen, which has its appropriate -representative in the solar spectrum, and another band of -nitrogen is similarly represented.” Dr. Draper states that -“in another photograph a heavy nitrogen line which in the -present one lies opposite an insufficiently exposed part of -the solar spectrum, corresponds to a comparison band in the -sun.”</p> - -<p>But one of the most remarkable points in Dr. Draper’s -paper is what he tells us respecting the visibility of these -lines in the spectrum itself. They fall, as I have mentioned, -in a part of the spectrum where the actinic energy is great -but the luminosity small; in fact, while this part of the -spectrum is the very strongest for photography, it is close to -the region of the visible spectrum,</p> - -<div class="poem-container"> -<div class="poem"><div class="stanza"> -<span class="iq">“Where the last gleamings of refracted light<br /></span> -<span class="i0">Die in the fainting violet away.”<br /></span> -</div></div> -</div> - -<p class="in0">It is therefore to be expected that those, if any, of the bright -lines of oxygen, will be least favourably shown for direct -vision, and most favourably for what might almost be called -photographic vision, where we see what photography records -for us. Yet Dr. Draper states that these bright lines of<span class="pagenum"><a id="Page_21">21</a></span> -oxygen can be readily seen. “The bright lines of oxygen -in the spectrum of the solar disc have not been hitherto perceived, -probably from the fact that in eye-observation bright -lines on a less bright background do not make the impression -on the mind that dark lines do. When attention is called -to their presence they are readily enough seen, even without -the aid of a reference spectrum. The photograph, however, -brings them into greater prominence.” As the lines of -oxygen are not confined to the indigo and violet, we may -fairly hope that the bright lines in other parts of the spectrum -of oxygen may be detected in the spectrum of the sun, now -that spectroscopists know that bright lines and not dark -lines are to be looked for.</p> - -<p>Dr. Draper remarks that from purely theoretic considerations -derived from terrestrial chemistry, and the nebular -hypothesis, the presence of oxygen in the sun might have -been strongly suspected; for this element is currently stated -to form eight-ninths of the water of the globe, one-third of -the crust of the earth, and one-fifth of the air, and should -therefore probably be a large constituent of every member -of the solar system. On the other hand, the discovery of -oxygen, and probably other non-metals, in the sun gives -increased strength to the nebular hypothesis, because to -many persons the absence of this important group has presented -a considerable difficulty. I have already remarked -on the circumstance that we cannot, according to the known -laws of gaseous diffusion, accept the reasoning of those who -have endeavoured to explain the small density of the outer -planets by the supposition that the lighter gases were left -behind by the great contracting nebulous mass, out of which, -on the nebular hypothesis, the solar system is supposed to -have been formed. It is important to notice, now, that if -on the one hand we find in the community of structure -between the sun and our earth, as confirmed by the discovery -of oxygen and nitrogen in the sun, evidence favouring -the theory according to which all the members of that system -were formed out of what was originally a single mass, we do<span class="pagenum"><a id="Page_22">22</a></span> -not find evidence against the theory (as those who have -advanced the explanation above referred to may be disposed -to imagine) in the recognition in the sun’s mass of enormous -quantities of one of these elements which, according to their -view, ought to be found chiefly in the outer members of the -solar system. If those who believe in the nebular hypothesis -(generally, that is, for many of the details of the hypothesis -as advanced by Laplace are entirely untenable in the present -position of physical science) had accepted the attempted -explanation of the supposed absence of the non-metallic -elements in the sun, they would now find themselves in a -somewhat awkward position. They would, in fact, be almost -bound logically to reject the nebular hypothesis, seeing that -one of the asserted results of the formation of our system, -according to that hypothesis, would have been disproved. -But so far as I know no supporter of the nebular hypothesis -possessing sufficient knowledge of astronomical facts and -physical laws to render his opinion of any weight, has ever -given in his adhesion to the unsatisfactory explanation -referred to.</p> - -<p>The view which I have long entertained respecting the -growth of the solar system—viz., that it had its origin, not -in contraction only or chiefly, but in combined processes of -contraction and accretion—seems to me to be very strongly -confirmed by Dr. Draper’s discovery. This would not be -the place for a full discussion of the reasons on which this -opinion is based. But I may remark that I believe no one who -applies the laws of physics, <em>as at present known</em>, to the theory -of the simple contraction of a great nebulous mass formerly -extending far beyond the orbit of Neptune, till, when planet -after planet had been thrown off, the sun was left in his -present form and condition in the centre, will fail to perceive -enormous difficulties in the hypothesis, or to recognize in -Dr. Draper’s discovery a difficulty added to those affecting -the hypothesis <em>so presented</em>. Has it ever occurred, I often -wonder, to those who glibly quote the nebular theory as -originally propounded, to inquire how far some of the processes<span class="pagenum"><a id="Page_23">23</a></span> -suggested by Laplace are in accordance with the now -known laws of physics? To begin with, the original nebulous -mass extending to a distance exceeding the earth’s distance -from the sun more than thirty times (this being only the -distance of Neptune), if we assign to it a degree of compression -making its axial diameter half its equatorial diameter, -would have had a volume exceeding the sun’s (roughly) -about 120,000,000,000 times, and in this degree its mean -density would have been less than the sun’s. This would -correspond to a density equal (roughly) to about one-400,000th -part of the density of hydrogen gas at atmospheric -pressure. To suppose that a great mass of matter, having -this exceedingly small mean density, and extending to a -distance of three or four thousand millions of miles from its -centre, could under any circumstances rotate as a whole, -or behave in other respects after the fashion attributed to the -gaseous embryon of the solar system in ordinary descriptions -of the nebular hypothesis, is altogether inconsistent with -correct ideas of physical and dynamical laws. It is absolutely -a necessity of any nebular hypothesis of the solar -system, that from the very beginning a central nucleus and -subordinate nuclei should form in it, and grow according to -the results of the motions (at first to all intents and purposes -independent) of its various parts. Granting this state of -things, we arrive, by considering the combined effects of -accretion and contraction, at a process of development -according fully as well as that ordinarily described with the -general relations described by Laplace, and accounting also -(in a general way) for certain peculiarities which are in no -degree explained by the ordinary theory. Amongst these -may specially be noted the arrangement and distribution of -the masses within the solar system, and the fact that so far -as spectroscopic evidence enables us to judge, a general -similarity of structure exists throughout the whole of the -system.</p> - -<p>Inquiring as to the significance of his discovery, Dr. -Draper remarks that it seems rather difficult “at first sight<span class="pagenum"><a id="Page_24">24</a></span> -to believe that an ignited<a id="FNanchor_5" href="#Footnote_5" class="fnanchor">5</a> gas in the solar atmosphere -should not be indicated by dark lines in the solar spectrum, -and should appear not to act under the law, ‘a gas when -ignited absorbs rays of the same refrangibility as those it -emits.’ But, in fact, the substances hitherto investigated -in the sun are really metallic vapours, hydrogen probably -coming under that rule. The non-metals obviously may -behave differently. It is easy to speculate on the causes of -such behaviour; and it may be suggested that the reason of -the non-appearance of a dark line may be that the intensity -of the light from a great thickness of ignited oxygen overpowers -the effect of the photosphere, just as, if a person -were to look at a candle-flame through a yard thickness of -sodium vapour, he would only see bright sodium lines, and -no dark absorption.”</p> - -<p>The reasoning here is not altogether satisfactory (or -else is not quite correctly expressed). In the first place, -the difficulty dealt with has no real existence. The law -that a gas when glowing absorbs rays of the same refrangibility -as it emits, does not imply that a gas between a -source of light and the observer will show its presence by -spectroscopic dark lines. A gas so placed <em>does</em> receive from -the source of light rays corresponding to those which it -emits itself, if it is cooler than the source of light; and it -absorbs them, being in fact heated by means of them, though -the gain of temperature may be dissipated as fast as received; -but if the gas is hotter, it emits more of those rays than it -absorbs, and will make its presence known by its bright lines. -This is not a matter of speculation, but of experiment. On<span class="pagenum"><a id="Page_25">25</a></span> -the other hand, the experiment suggested by Dr. Draper -would not have the effect he supposes, if it were correctly -made. Doubtless, if the light from a considerable area of -dully glowing sodium vapour were received by the spectroscope -at the same time as the light of a candle-flame seen -through the sodium vapour, the light of the sodium vapour -overcoming that of the candle-flame would indicate its -presence by bright lines; but if light were received only -from that portion of the sodium vapour which lay between -the eye and the candle-flame, then I apprehend that the dark -lines of sodium would not only be seen, but would be conspicuous -by their darkness.</p> - -<p>It is in no cavilling spirit that I indicate what appears to -me erroneous in a portion of Dr. Draper’s reasoning on his -great discovery. The entire significance of the discovery -depends on the meaning attached to it, and therefore it is -most desirable to ascertain what this meaning really is. -There can be no doubt, I think, that we are to look for the -true interpretation of the brightness of the oxygen lines in -the higher temperature of the oxygen, not in the great depth -of oxygen above the photospheric level. The oxygen which -produces these bright lines need not necessarily be above -the photosphere at all. (In fact, I may remark here that -Dr. Draper, in a communication addressed to myself, mentions -that he has found no traces at present of oxygen above -the photosphere, though I had not this circumstance in my -thoughts in reasoning down to the conclusion that the part -of the oxygen effective in showing these bright lines lies -probably below the visible photosphere.) Of course, if the -photosphere were really composed of glowing solid and -liquid matter, or of masses of gas so compressed and so -intensely heated as to give a continuous spectrum, no gas -existing below the photosphere could send its light through, -nor could its presence, therefore, be indicated in any spectroscopic -manner. But the investigations which have been -made into the structure of the photosphere as revealed by -the telescope, and in particular the observations made by<span class="pagenum"><a id="Page_26">26</a></span> -Professor Langley, of the Alleghany Observatory, show that -we have not in the photosphere a definite bounding envelope -of the sun, but receive light from many different depths -below that spherical surface, 425,000 miles from the sun’s -centre, which we call the photospheric level. We receive -more light from the centre of the solar disc, I feel satisfied, -not solely because the absorptive layer through which we -there see the sun is shallower, but partly, and perhaps chiefly, -because we there receive light from some of the interior and -more intensely heated parts of the sun.<a id="FNanchor_6" href="#Footnote_6" class="fnanchor">6</a> Should this prove -to be the case, it may be found possible to do what heretofore -astronomers have supposed to be impossible—to ascertain -in some degree how far and in what way the constitution -of the sun varies below the photosphere, which, so far as -ordinary telescopic observation is concerned, seems to present -a limit below which researches cannot be pursued.</p> - -<p>I hope we shall soon obtain news from Dr. Huggins’s -Observatory that the oxygen lines have been photographed, -and possibly the bright lines of other elements recognized in -the solar spectrum. Mr. Lockyer also, we may hope, will -exercise that observing skill which enabled him early to -recognize the presence of bright hydrogen lines in the spectrum -of portions of the sun’s surface, to examine that -spectrum for other bright lines.</p> - -<p>I do not remember any time within the last twenty years -when the prospects of fresh solar discoveries seemed more -hopeful than they do at present. The interest which has of -late years been drawn to the subject has had the effect of<span class="pagenum"><a id="Page_27">27</a></span> -enlisting fresh recruits in the work of observation, and many -of these may before long be heard of as among those who -have employed Dr. Draper’s method successfully.</p> - -<p>But I would specially call attention to the interest which -attaches to Dr. Draper’s discovery and to the researches -likely to follow from it, in connection with a branch of research -which is becoming more and more closely connected -year by year with solar investigations—I mean stellar spectroscopy. -We have seen the stars divided into orders -according to their constitution. We recognize evidence -tending to show that these various orders depend in part -upon age—not absolute but relative age. There are among -the suns which people space some younger by far than our -sun, others far older, and some in a late stage of stellar -decrepitude. Whether as yet spectroscopists have perfectly -succeeded in classifying these stellar orders in such sort that -the connection between a star’s spectrum and the star’s age -can be at once determined, may be doubtful. But certainly -there are reasons for hoping that before long this will be -done. Amongst the stars, and (strange to say) among -celestial objects which are not stars, there are suns in every -conceivable stage of development, from embryon masses -not as yet justly to be regarded as suns, to masses which -have ceased to fulfil the duties of suns. Among the more -pressing duties of spectroscopic analysis at the present time -is the proper classification of these various orders of stars. -Whensoever that task shall have been accomplished, strong -light, I venture to predict, will be thrown on our sun’s present -condition, as well as on his past history, and on that future -fate upon which depends the future of our earth.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_28">28</a></span></p> - -<div class="chapter"> -<h2><a id="SUN-SPOT_STORM_AND_FAMINE"></a><i>SUN-SPOT, STORM, AND FAMINE.</i></h2> -</div> - -<p class="in0">During the last five or six years a section of the scientific -world has been exercised with the question how far the condition -of the sun’s surface with regard to spots affects our -earth’s condition as to weather, and therefore as to those -circumstances which are more or less dependent on weather. -Unfortunately, the question thus raised has not presented -itself alone, but in company with another not so strictly -scientific, in fact, regarded by most men of science as closely -related to personal considerations—the question, namely, -whether certain indicated persons should or should not be -commissioned to undertake the inquiry into the scientific -problem. But the scientific question itself ought not to be -less interesting to us because it has been associated, correctly -or not, with the wants and wishes of those who advocate -the endowment of science. I propose here to consider the -subject in its scientific aspect only, and apart from any bias -suggested by the appeals which have been addressed to the -administrators of the public funds.</p> - -<p>It is hardly necessary to point out, in the first place, that -all the phenomena of weather are directly referable to the -sun as their governing cause. His rays poured upon our air -cause the more important atmospheric currents directly. Indirectly -they cause modifications of these currents, because -where they fall on water or on moist surfaces they raise -aqueous vapour into the air, which, when it returns to the -liquid form as cloud, gives up to the surrounding air the -heat which had originally vaporized the water. In these<span class="pagenum"><a id="Page_29">29</a></span> -ways, directly or indirectly, various degrees of pressure and -temperature are brought about in the atmospheric envelope -of the earth, and, speaking generally, all air currents, from the -gentlest zephyr to the fiercest tornado, are the movements -by which the equilibrium of the air is restored. Like other -movements tending to restore equilibrium, the atmospheric -motions are oscillatory. Precisely as when a spring has been -bent one way, it flies not back only, but beyond the mean -position, till it is almost equally bent the other way, so the -current of air which rushes in towards a place of unduly -diminished pressure does more than restore the mean -pressure, so that presently a return current carries off the -excess of air thus carried in. We may say, indeed, that the -mean pressure at any place scarcely ever exists, and when it -exists for a time the resulting calm is of short duration. Just -as the usual condition of the sea surface is one of disturbance, -greater or less, so the usual condition of the air at every spot -on the earth’s surface is one of motion not of quiescence. -Every movement of the air, thus almost constantly perturbed, -is due directly or indirectly to the sun.</p> - -<p>So also every drop of rain or snow, every particle of -liquid or of frozen water in mist or in cloud, owes its birth -to the sun. The questions addressed of old to Job, “Hath -the rain a father? or who hath begotten the drops of dew? -out of whose womb came the ice? and the hoary frost of -heaven, who hath gendered it?” have been answered by -modern science, and to every question the answer is, The -Sun. He is parent of the snow and hail, as he is of the -moist warm rains of summer, of the ice which crowns the -everlasting hills, and of the mist which rises from the valleys -beneath his morning rays.</p> - -<p>Since, then, the snow that clothes the earth in winter as -with a garment, and the clouds that in due season drop -fatness on the earth, are alike gendered by the sun; since -every movement in our air, from the health-bringing breeze -to the most destructive hurricane, owns him as its parent; -we must at the outset admit, that if there is any body<span class="pagenum"><a id="Page_30">30</a></span> -external to the earth whose varying aspect or condition can -inform us beforehand of changes which the weather is to -undergo, the sun is that body. That for countless ages the -moon should have been regarded as the great weather-breeder, -shows only how prone men are to recognize in -apparent changes the true cause of real changes, and how -slight the evidence is on which they will base laws of association -which have no real foundation in fact. Every one can -see when the moon is full, or horned, or gibbous, or half-full; -when her horns are directed upwards, or downwards, or -sideways. And as the weather is always changing, even -as the moon is always changing, it must needs happen that -from time to time changes of weather so closely follow -changes of the moon as to suggest that the two orders of -change stand to each other in the relation of cause and -effect. Thus rough rules (such as those which Aratus has -handed down to us) came to be formed, and as (to use -Bacon’s expression) men mark when such rules hit, and -never mark when they miss, a system of weather lore -gradually comes into being, which, while in one sense based -on facts, has not in reality a particle of true evidence in its -favour—every single fact noted for each relation having -been contradicted by several unnoted facts opposed to the -relation. There could be no more instructive illustration of -men’s habits in such matters than the system of lunar -weather wisdom in vogue to this day among seamen, though -long since utterly disproved by science. But let it be remarked -in passing, that in leaving the moon, which has no -direct influence, and scarcely any indirect influence, on the -weather, for the sun, which is all-powerful, we have not got -rid of the mental habits which led men so far astray in -former times. We shall have to be specially careful lest it -lead us astray yet once more, perhaps all the more readily -because of the confidence with which we feel that, at the -outset anyway, we are on the right road.</p> - -<p>I suppose there must have been a time when men were -not altogether certain whether the varying apparent path of<span class="pagenum"><a id="Page_31">31</a></span> -the sun, as he travels from east to west every day, has any -special effect on the weather. It seems so natural to us to -recognize in the sun’s greater mid-day elevation and longer -continuance above the horizon in summer, the cause of the -greater warmth which then commonly prevails, that we find it -difficult to believe that men could ever have been in doubt -on this subject. Yet it is probable that a long time passed -after the position of the sun as ruler of the day had been -noticed, before his power as ruler of the seasons was recognized. -I cannot at this moment recall any passage in the -Bible, for example, in which direct reference is made to the -sun’s special influence in bringing about the seasons, or -any passage in very ancient writings referring definitely to -the fact that the weather changes with the changing position -of the sun in the skies (as distinguished from the star-sphere), -and with the changing length of the day. “While -the earth remaineth,” we are told in Genesis, “seed-time -and harvest, and cold and heat, and summer and winter, -and day and night, shall not cease;” but there is no reference -to the sun’s aspect as determining summer and winter. -We find no mention of any of the celestial signs of the -seasons anywhere in the Bible, I think, but such signs as -are mentioned in the parable of the fig tree—“When his -branch is yet tender, and putteth forth leaves, ye know that -summer is nigh.” Whether this indicates or not that the -terrestrial, rather than the celestial signs of the progress of -the year were chiefly noted by men in those times, it is -tolerably certain that in the beginning a long interval must -have elapsed between the recognition of the seasons themselves, -and the recognition of their origin in the changes of -the sun’s apparent motions.</p> - -<p>When this discovery was effected, men made the most -important and, I think, the most satisfactory step towards the -determination of cyclic associations between solar and terrestrial -phenomena. It is for that reason that I refer specially -to the point. In reality, it does not appertain to my subject, -for seasons and sun-spots are not associated. But it admirably<span class="pagenum"><a id="Page_32">32</a></span> -illustrates the value of cyclic relations. Men might -have gone on for centuries, we may conceive, noting the -recurrence of seed-time and harvest-time, summer and -winter, recognizing the periodical returns of heat and cold, -and (in some regions) of dry seasons and wet seasons, of -calm and storm, and so forth, without perceiving that the -sun runs through his changes of diurnal motion in the same -cyclic period. We can imagine that some few who might -notice the connection between the two orders of celestial -phenomena would be anxious to spread their faith in the -association among their less observant brethren. They -might maintain that observatories for watching the motions -of the sun would demonstrate either that their belief was -just or that it was not so, would in fact dispose finally of -the question. It is giving the most advantageous possible -position to those who now advocate the erection of solar -observatories for determining what connection, if any, may -exist between sun-spots and terrestrial phenomena, thus to -compare them to observers who had noted a relation which -unquestionably exists. But it is worthy of notice that if -those whom I have imagined thus urging the erection of an -observatory for solving the question whether the sun rules -the seasons, and to some degree regulates the recurrence -of dry or rainy, and of calm or stormy weather, had promised -results of material value from their observations, they -would have promised more than they could possibly have -performed. Even in this most favourable case, where the -sun is, beyond all question, the efficient ruling body, where -the nature of the cyclic change is most exactly determinable, -and where even the way in which the sun acts can be -exactly ascertained, no direct benefit accrues from the -knowledge. The exact determination of the sun’s apparent -motions has its value, and this value is great, but it is most -certainly not derived from any power of predicting the recurrence -of those phenomena which nevertheless depend -directly on the sun’s action. The farmer who in any -given year knows from the almanac the exact duration of<span class="pagenum"><a id="Page_33">33</a></span> -daylight, and the exact mid-day elevation of the sun for every -day in the year, is not one whit better able to protect his -crops or his herds against storm or flood than the tiller of -the soil or the tender of flocks a hundred thousand years or -so ago, who knew only when seed-time and summer and -harvest-time and winter were at hand or in progress.</p> - -<p>The evidence thus afforded is by no means promising, -then, so far as the prediction of special storms, or floods, -or droughts is concerned. It would seem that if past experience -can afford any evidence in such matters, men may -expect to recognize cycles of weather change long before -they recognize corresponding solar cycles (presuming always -that such cycles exist), and that they may expect to find -the recognition of such association utterly barren, so far as -the possibility of predicting definite weather changes is -concerned. It would seem that there is no likelihood of -anything better than what Sir J. Herschel said <em>might</em> be -hoped for hereafter. “A lucky hit may be made; nay, -some rude approach to the perception of a ‘cycle of -seasons’ may <em>possibly</em> be obtainable. But no person in his -senses would alter his plans of conduct for six months in -advance in the most trifling particular on the faith of any -special prediction of a warm or a cold, a wet or a dry, a -calm or a stormy, summer or winter”—far less of a great -storm or flood announced for any special day.</p> - -<p>But let us see what the cycle association between solar -spots and terrestrial weather actually is, or rather of what -nature it promises to be, for as yet the true nature of the -association has not been made out.</p> - -<p>It has been found that in a period of about eleven years -the sun’s surface is affected by what may be described as a -wave of sun-spots. There is a short time—a year or so—during -which scarce any spots are seen; they become more -and more numerous during the next four or five years, until -they attain a maximum of frequency and size; after this they -wane in number and dimensions, until at length, about eleven -years from the time when he had before been freest from<span class="pagenum"><a id="Page_34">34</a></span> -spots, he attains again a similar condition. After this the -spots begin to return, gradually attain to a maximum, then -gradually diminish, until after eleven more years have -elapsed few or none are seen. It must not be supposed -that the sun is always free from spots at the time of minimum -spot frequency, or that he always shows many and large -spots at the time of maximum spot frequency. Occasionally -several very large spots, and sometimes singularly large spots, -have been seen in the very heart of the minimum spot season, -and again there have been occasions when scarcely any spots -have been seen for several days in the very heart of the -maximum spot season. But, taking the average of each -year, the progression of the spots in number and frequency -from minimum to maximum, and their decline from maximum -to minimum, are quite unmistakeable.</p> - -<p>Now there are some terrestrial phenomena which we -might expect to respond in greater or less degree to the -sun’s changes of condition with respect to spots. We cannot -doubt that the emission both of light and of heat is -affected by the presence of spots. It is not altogether clear -in what way the emission is affected. We cannot at once -assume that because the spots are dark the quantity of sunlight -must be less when the spots are numerous; for it may -well be that the rest of the sun’s surface may at such times be -notably brighter than usual, and the total emission of light -may be greater on the whole instead of less. Similarly of -the emission of heat. It is certain that when there are many -spots the surface of the sun is far less uniform in brightness -than at other times. The increase of brightness all round -the spots is obvious to the eye when the sun’s image, duly -enlarged, is received upon a screen in a darkened room. -Whether the total emission of light is increased or diminished -has not yet been put to the test. Professor Langley, of the -Alleghany Observatory, near Pittsburg, U.S., has carefully -measured the diminution of the sun’s emission of light and -heat on the assumption that the portion of the surface not -marked by spots remains unchanged in lustre. But until<span class="pagenum"><a id="Page_35">35</a></span> -the total emission of light and heat at the times of maximum -and minimum has been measured, without any assumption of -the kind, we cannot decide the question.</p> - -<p>More satisfactory would seem to be the measurements -which have been made by Professor Piazzi Smyth, at -Edinburgh, and later by the Astronomer Royal at Greenwich, -into the underground temperature of the earth. By -examining the temperature deep down below the surface, all -local and temporary causes of change are eliminated, and -causes external to the earth can alone be regarded as -effective in producing systematic changes. “The effect -is very slight,” I wrote a few years ago, “indeed barely -recognizable. I have before me as I write Professor Smyth’s -sheet of the quarterly temperatures from 1837 to 1869 at -depths of 3, 6, 12, and 24 French feet. Of course the most -remarkable feature, even at the depth of 24 feet, is the -alternate rise and fall with the seasons. But it is seen that, -while the range of rise and fall remains very nearly constant, -the crests and troughs of the waves lie at varying levels.” -After describing in the essay above referred to, which appears -in my “Science Byways,” the actual configuration of the -curves of temperature both for seasons and for years, and -the chart in which the sun-spot waves and the temperature -waves are brought into comparison, I was obliged to admit -that the alleged association between the sun-spot period and -the changes of underground temperature did not seem to -me very clearly made out. It appears, however, there is a -slight increase of temperature at the time when the sun-spots -are least numerous.</p> - -<p>That the earth’s magnetism is affected by the sun’s -condition with respect to spots, seems to have been more -clearly made out, though it must be noted that the -Astronomer Royal considers the Greenwich magnetic observations -inconsistent with this theory. It seems to have -been rendered at least extremely probable that the daily -oscillation of the magnetic needle is greater when spots are -numerous than when there are few spots or none. Magnetic<span class="pagenum"><a id="Page_36">36</a></span> -storms are also more numerous at the time of maximum -spot-frequency, and auroras are then more common. (The -reader will not fall into the mistake of supposing that -magnetic storms have the remotest resemblance to hurricanes, -or rainstorms, or hailstorms, or even to thunderstorms, -though the thunderstorm is an electrical phenomenon. -What is meant by a magnetic storm is simply such a condition -of the earth’s frame that the magnetic currents traversing -it are unusually strong.)</p> - -<p>Thus far, however, we have merely considered relations -which we might fairly expect to find affected by the sun’s -condition as to spots. A slight change in his total brightness -and in the total amount of heat emitted by him may -naturally be looked for under circumstances which visibly -affect the emission of light, and presumably affect the -emission of heat also, from portions of his surface. Nor -can we wonder if terrestrial magnetism, which is directly -dependent on the sun’s emission of heat, should be affected -by the existence of spots upon his surface.</p> - -<p>It is otherwise with the effects which have recently been -associated with the sun’s condition. It may or may not -prove actually to be the case that wind and rain vary in -quantity as the sun-spots vary in number (at least when we -take in both cases the average for a year, or for two or three -years), but it cannot be said that any such relation was antecedently -to be expected. When we consider what the sun -actually does for our earth, it seems unlikely that special -effects such as these should depend on relatively minute -peculiarities of the sun’s surface. There is our earth, with -her oceans and continents, turning around swiftly on her -axis, and exposed to his rays as a whole. Or, inverting the -way of viewing matters, there is the sun riding high in the -heavens of any region of the earth, pouring down his rays -upon that region. We can understand how in the one case -that rotating orb of the earth may receive rather more or -rather less heat from the sun when he is spotted than when -he is not, or how in the other way of viewing matters, that<span class="pagenum"><a id="Page_37">37</a></span> -orb of the sun may give to any region rather more or rather -less heat according as his surface is more or less spotted. -But that in special regions of that rotating earth storms -should be more or less frequent or rainfall heavier or lighter, -as the sun’s condition changes through the exceedingly small -range of variation due to the formation of spots, seems antecedently -altogether unlikely; and equally unlikely the idea -that peculiarities affecting limited regions of the sun’s surface -should affect appreciably the general condition of the earth. -If a somewhat homely comparison may be permitted, we can -well understand how a piece of meat roasting before a fire -may receive a greater or less supply of heat on the whole as -the fire undergoes slight local changes (very slight indeed -they must be, that the illustration may be accurate); but it -would be extremely surprising if, in consequence of such -slight changes in the fire, the roasting of particular portions -of the joint were markedly accelerated or delayed, or affected -in any other special manner.</p> - -<p>But of course all such considerations as to antecedent -probabilities must give way before the actual evidence of -observed facts. Utterly inconsistent with all that is yet -known of the sun’s physical action, as it may seem, on <i xml:lang="la" lang="la">à -priori</i> grounds, to suppose that spots, currents, or other local -disturbances of the sun’s surface could produce any but -general effects on the earth as a whole, yet if we shall find that -particular effects are produced in special regions of the earth’s -surface in cycles unmistakably synchronizing with the solar-spot-cycle, -we must accept the fact, whether we can explain -it or not. Only let it be remembered at the outset that the -earth is a large place, and the variations of wind and calm, -rain and drought, are many and various in different regions. -Whatever place we select for examining the rainfall, for -example, we are likely to find, in running over the records -of the last thirty years or so, some seemingly oscillatory -changes; in the records of the winds, again, we are likely to -find other seemingly oscillatory changes; if none of these -records provide anything which seems in any way to correspond<span class="pagenum"><a id="Page_38">38</a></span> -with the solar spot-cycle, we may perchance find some -such cycle in the relative rainfall of particular months, or in -the varying wetness or dryness of particular winds, and so -forth. Or, if we utterly fail to find any such relation in one -place we may find it in another, or not improbably in half-a-dozen -places among the hundreds which are available for the -search. If we are content with imperfect correspondence -between some meteorological process or another and the -solar-spot cycle, we shall be exceedingly unfortunate indeed -if we fail to find a score of illustrative instances. And if we -only record these, without noticing any of the cases where -we fail to find any association whatever—in other words, as -Bacon puts it, if “we note when we hit and never note when -we miss,” we shall be able to make what will seem a very -strong case indeed. But this is not exactly the scientific -method in such cases. By following such a course, indeed, -we might prove almost anything. If we take, for instance, -a pack of cards, and regard the cards in order as corresponding -to the years 1825 to 1877, and note their colours as -dealt <em>once</em>, we shall find it very difficult to show that there is -any connection whatever between the colours of the cards -corresponding to particular years and the number of spots -on the sun’s face. But if we repeat the process a thousand -times, we shall find certain instances among the number, in -which red suits correspond to all the years when there are -many spots on the sun, and black suits to all the years when -there are few spots on the sun. If now we were to publish -all such deals, without mentioning anything at all about the -others which showed no such association, we should go far -to convince a certain section of the public that the condition -of the sun as to spots might hereafter be foretold by the -cards; whence, if the public were already satisfied that the -condition of the sun specially affects the weather of particular -places, it would follow that the future weather of these places -might also be foretold by the cards.</p> - -<p>I mention this matter at the outset, because many who -are anxious to find some such cycle of seasons as Sir John<span class="pagenum"><a id="Page_39">39</a></span> -Herschel thought might be discovered, have somewhat overlooked -the fact that we must not hunt down such a cycle -<i xml:lang="la" lang="la">per fas et nefas</i>. “Surely in meteorology as in astronomy,” -Mr. Lockyer writes, for instance, “the thing to hunt down -is a cycle, and if that is not to be found in the temperate -zone, then go to the frigid zones or the torrid zone to look -for it; and if found, then above all things and in whatever -manner, lay hold of, study, and read it, and see what it -means.” There can be no doubt that this is the way to find -a cycle, or at least to find what looks like a cycle, but the -worth of a cycle found in this way will be very questionable.<a id="FNanchor_7" href="#Footnote_7" class="fnanchor">7</a></p> - -<p>I would not have it understood, however, that I consider -all the cycles now to be referred to as unreal, or even that -the supposed connection between them and the solar cycle -has no existence. I only note that there are thousands, if -not tens of thousands, of relations among which cycles may -be looked for, and that there are perhaps twenty or thirty -cases in which some sort of cyclic association between certain -meteorological relations and the period of the solar spots -presents itself. According to the recognized laws of probability, -some at least amongst these cases must be regarded -as accidental. Some, however, may still remain which are -not accidental.</p> - -<p>Among the earliest published instances may be mentioned -Mr. Baxendell’s recognition of the fact that during a certain -series of years, about thirty, I think, the amount of rainfall -at Oxford was greater under west and south-west winds than -under south and south-east winds when sun-spots were most -numerous, whereas the reverse held in years when there were -no spots or few. Examining the meteorological records of<span class="pagenum"><a id="Page_40">40</a></span> -St. Petersburg, he found that a contrary state of things prevailed -there.</p> - -<p>The Rev. Mr. Main, Director of the Radcliffe Observatory -at Oxford, found that westerly winds were slightly -more common (as compared with other winds) when sun-spots -were numerous than when they were few.</p> - -<p>Mr. Meldrum, of Mauritius, has made a series of statistical -inquiries into the records of cyclones which have -traversed the Indian Ocean between the equator and 34 -degrees south latitude, in each year from 1856 to 1877, -noting the total distances traversed by each, the sums of -their radii and areas, their duration in days, the sums of -their total areas, and their relative areas. His researches, be -it marked in passing, are of extreme interest and value, -whether the suggested connection between sun-spots and -cyclones (in the region specified) be eventually found to be -a real one or not. The following are his results, as described -in <cite>Nature</cite> by a writer who manifestly favours very strongly -the doctrine that an intimate association exists between -solar maculation (or spottiness) and terrestrial meteorological -phenomena:—</p> - -<p>“The period embraces two complete, or all but complete, -sun-spot periods, the former beginning with 1856 and ending -in 1867, and the latter extending from 1867 to about the -present time [1877]. The broad result is that the number of -cyclones, the length and duration of their courses, and the -extent of the earth’s surface covered by them all, reach the -maximum in each sun-spot period during the years of -maximum maculation, and fall to the minimum during the -years of minimum maculation. The peculiar value of these -results lies in the fact that the portion of the earth’s surface -over which this investigation extends, is, from its geographical -position and what may be termed its meteorological homogeneity, -singularly well fitted to bring out prominently any -connection that may exist between the condition of the sun’s -surface and atmospheric phenomena.”</p> - -<p>The writer proceeds to describe an instance in which<span class="pagenum"><a id="Page_41">41</a></span> -Mr. Meldrum predicted future meteorological phenomena, -though without specifying the exact extent to which Mr. -Meldrum’s anticipations were fulfilled or the reverse. “A -drought commenced in Mauritius early in November,” he -says, “and Mr. Meldrum ventured (on December 21) to -express publicly his opinion that probably the drought would -not break up till towards the end of January, and that it -might last till the middle of February, adding that up to -these dates the rainfall of the island would probably not -exceed 50 per cent. of the mean fall. This opinion was an -inference grounded on past observations, which show that -former droughts have lasted from about three to three and -a half months, and that these droughts have occurred in the -years of minimum sun-spots, or, at all events, in years when -the spots were far below the average, such as 1842, 1843, -1855, 1856, 1864, 1866, and 1867, and that now we are -near the minimum epoch of sun-spots. It was further stated -that the probability of rains being brought earlier by a -cyclone was but slight, seeing that the season for cyclones -is not till February or March, and that no cyclone whatever -visited Mauritius during 1853–56 and 1864–67, the years of -minimum sun-spots. From the immense practical importance -of this application of the connection between sun-spots and -weather to the prediction of the character of the weather of -the ensuing season, we shall look forward with the liveliest -interest to a detailed statement of the weather which actually -occurred in that part of the Indian Ocean from November -to March last [1876].”</p> - -<p>It was natural that the great Indian famine, occurring at -a time when sun-spots were nearly at a minimum, should by -some be directly associated with a deficiency of sun-spots. -In this country, indeed, we have had little reason, during -the last two or three years of few sun-spots, to consider that -drought is one of the special consequences to be attributed -to deficient solar maculation. But in India it may be -different, or at least it may be different in Madras, for it has -been satisfactorily proved that in some parts of India the<span class="pagenum"><a id="Page_42">42</a></span> -rainfall increases in inverse, not in direct proportion, to -the extent of solar maculation. Dr. Hunter has shown to -the satisfaction of many that at Madras there is “a cycle -of rainfall corresponding with the period of solar maculation.” -But Mr. E. D. Archibald, who is also thoroughly -satisfied that the sun-spots affect the weather, remarks that -Dr. Hunter has been somewhat hasty in arguing that the -same conditions apply throughout the whole of Southern -India. “This hasty generalization from the results of one -station situated in a vast continent, the rainfall of which -varies completely, both in amount and the season in which -it falls, according to locality, has been strongly contested -by Mr. Blanford, the Government Meteorologist, who, in -making a careful comparison of the rainfalls of seven -stations, three of which (Madras, Bangalore, and Mysore) -are in Southern India, the others being Bombay, Najpore, -Jubbulpore, and Calcutta, finds that, with the exception of -Najpore in Central India, which shows some slight approach -to the same cyclical variation which is so distinctly marked -in the Madras registers, the rest of the stations form complete -exceptions to the rule adduced for Madras, in many -of them the hypothetical order of relation being reversed. -Mr. Blanford, however, shows that, underlying the above -irregularities, a certain cyclical variation exists on the -average at all the stations, the amount, nevertheless, being -so insignificant (not more than 9 per cent. of the total falls) -that it could not be considered of sufficient magnitude to -become a direct factor in the production of famine. It thus -appears that the cycle of rainfall which is considered to be -the most important element in causing periodic famines has -only been proved satisfactorily for the town of Madras. It -may perhaps hold for the Carnatic and Northern Siccars, -the country immediately surrounding Madras, though perhaps, -owing to the want of rainfall registers in these districts, -evidence with regard to this part is still wanting.” -On this Mr. Archibald proceeds to remark that, though Dr. -Hunter has been only partially successful, the value of his<span class="pagenum"><a id="Page_43">43</a></span> -able pamphlet is not diminished in any way, “an indirect -effect of which has been to stimulate meteorological inquiry -and research in the same direction throughout India. The -meteorology of this country (India), from its peculiar and -tropical position, is in such complete unison with any -changes that may arise from oscillations in the amount of -solar radiation, and their effects upon the velocity and direction -of the vapour-bearing winds, that a careful study of -it cannot fail to discover meteorological periodicities in close -connection with corresponding periods of solar disturbance.” -So, indeed, it would seem.</p> - -<p>The hope that famines may be abated, or, at least, some -of their most grievous consequences forestalled by means of -solar observatories, does not appear very clearly made out. -Rather it would seem that the proper thing to do is to -investigate the meteorological records of different Indian -regions, and consider the resulting evidence of cyclic -changes without any special reference to sun-spots; for if -sun-spots may cause drought in one place, heavy rainfall in -another, winds here and calms there, it seems conceivable -that the effects of sun-spots may differ at different times, as -they manifestly do in different places.</p> - -<p>Let us turn, however, from famines to shipwrecks. Perhaps, -if we admit that cyclones are more numerous, and -blow more fiercely, and range more widely, even though it -be over one large oceanic region only, in the sun-spot -seasons than at other times, we may be assured, without -further research, that shipwrecks will, on the whole, be more -numerous near the time of sun-spot maxima than near the -time of sun-spot minima.</p> - -<p>The idea that this may be so was vaguely shadowed -forth in a poem of many stanzas, called “The Meteorology -of the Future: a Vision,” which appeared in <cite>Nature</cite> for -July 5, 1877. I do not profess to understand precisely -what the object of this poem may have been—I mean, -whether it is intended to support or not the theory that -sun-spots influence the weather. Several stanzas are very<span class="pagenum"><a id="Page_44">44</a></span> -humorous, but the object of the humour is not manifest. -The part referred to above is as follows:—Poor Jack lies -at the bottom of the sea in 1881, and is asked in a spiritual -way various questions as to the cause of his thus coming -to grief. This he attributed to the rottenness of the ship -in which he sailed, to the jobbery of the inspector, to the -failure of the system of weather telegraphing, and so forth. -But, says the questioner, there was one</p> - -<div class="poem-container"> -<div class="poem"><div class="stanza"> -<span class="iq">“In fame to none will yield,<br /></span> -<span class="i0">He led the band who reaped renown<br /></span> -<span class="i0">On India’s famine field.<br /></span> -</div><div class="stanza"> -<span class="iq">“Was he the man to see thee die?<br /></span> -<span class="i0">Thou wilt not tax him—come?<br /></span> -<span class="i0">The dead man groaned—‘<em>I met my death</em><br /></span> -<span class="i0"><em>Through a sun-spot maximum</em>.’”<br /></span> -</div></div> -</div> - -<p>The first definite enunciation, however, of a relation -between sun-spots and shipwrecks appeared in September, -1876. Mr. Henry Jeula, in the <cite>Times</cite> for September 19, -stated that Dr. Hunter’s researches into the Madras rainfall -had led him to throw together the scanty materials available -relating to losses posted on Lloyd’s loss book, to ascertain -if any coincidences existed between the varying number of -such losses and Dr. Hunter’s results. “For,” he proceeds, -“since the cycle of rainfall at Madras coincides, I am -informed, with the periodicity of the cyclones in the adjoining -Bay of Bengal” (a relation which is more than doubtful) -“as worked out by the Government Astronomer at Mauritius” -(whose researches, however, as we have seen, related -to a region remote from the Bay of Bengal), “some coincidence -between maritime casualties, rainfalls, and sun-spots -appeared at least possible.” In passing, I may note that -if any such relation were established, it would be only an -extension of the significance of the cycle of cyclones, and -could have no independent value. It would certainly follow, -if the cycle of cyclones is made out, that shipwrecks being -more numerous, merchants would suffer, and we should<span class="pagenum"><a id="Page_45">45</a></span> -have the influence of the solar spots asserting itself in the -<cite>Gazette</cite>. From the cyclic derangement of monetary and -mercantile matters, again, other relations also cyclic in -character would arise. But as all these may be inferred -from the cycle of cyclones once this is established, we could -scarcely find in their occurrence fresh evidence of the necessity -of that much begged-for solar observatory. The last -great monetary panic in this country, by the way, occurred -in 1866, at a time of minimum solar maculation. Have we -here a decisive proof that the sun rules the money market, -the bank rate of discount rising to a maximum as the sun-spots -sink to a minimum, and <i xml:lang="la" lang="la">vice versâ</i>? The idea is -strengthened by the fact that the American panic in 1873 -occurred when spots were very numerous, and its effects -have steadily subsided as the spots have diminished in -number; for this shows that the sun rules the money market -in America on a principle diametrically opposed to that on -which he (manifestly) rules the money market in England, -precisely as the spots cause drought in Calcutta and -plenteous rainfall at Madras, wet south-westers and dry -south-westers at Oxford, and wet south-easters and dry -south-easters at St. Petersburg. Surely it would be unreasonable -to refuse to recognize the weight of evidence which -thus tells on both sides at once.</p> - -<p>To return, however, to the sun’s influence upon shipwrecks.</p> - -<p>Mr. Jeula was “only able to obtain data for two complete -cycles of eleven years, namely, from 1855 to 1876 -inclusive, while the period investigated by Dr. Hunter extended -from 1813 to 1876, and his observations related to -Madras and its neighbourhood only, while the losses posted -at Lloyd’s occurred to vessels of various countries, and -happened in different parts of the world. It was necessary -to bring these losses to some common basis of comparison, -and the only available one was the number of ‘British -registered vessels of the United Kingdom and Channel -Islands’—manifestly an arbitrary one. I consequently cast<span class="pagenum"><a id="Page_46">46</a></span> -out the percentage of losses posted each year upon the -number of registered vessels for the same year, and also -the percentage of losses posted in each of the eleven years -of the two cycles upon the total posted in each complete -cycle, thus obtaining two bases of comparison independent -of each other.”</p> - -<p>The results may be thus presented:—</p> - -<p>Taking the four years of each cycle when sun-spots were -least in number, Mr. Jeula found the mean percentage of -losses in registered vessels of the United Kingdom and -Channel Islands to be 11·13, and the mean percentage of -losses in the total posted in the entire cycle of eleven years -to be 8·64.</p> - -<p>In the four years when sun-spots were intermediate in -number, that is in two years following the minimum and in -two years preceding the minimum, the respective percentages -were 11·91 and 9·21.</p> - -<p>Lastly, in the three years when sun-spots were most -numerous, these percentages were, respectively, 12·49 and -9·53.</p> - -<p>That the reader may more clearly understand what is -meant here by percentages, I explain that while the numbers -11·13, 11·91 and 12·49 simply indicate the average number -of wrecks (per hundred of all the ships registered) which -occurred in the several years of the eleven-years cycle, the -other numbers, 8·64, 19·21, and 9·53, indicate the average -number of wrecks (per hundred of wrecks recorded) during -eleven successive years, which occurred in the several years -of the cycle. The latter numbers seem more directly to the -purpose; and as the two sets agree pretty closely, we may -limit our attention to them.</p> - -<p>Now I would in the first place point out that it would -have been well if the actual number or percentage had been -indicated for each year of the cycle, instead of for periods of -four years, four years, and three years. Two eleven-year -cycles give in any case but meagre evidence, and it would -have been well if the evidence had been given as fully as<span class="pagenum"><a id="Page_47">47</a></span> -possible. If we had a hundred eleven-yearly cycles, and -took the averages of wrecks for the four years of minimum -solar maculation, the four intermediate years, and the three -years of maximum maculation, we might rely with considerable -confidence on the result, because accidental peculiarities -one way or the other could be eliminated. But in two -cycles only, such peculiarities may entirely mask any cyclic -relation really existing, and appear to indicate a relation -which has no real existence. If the percentages had been -given for each year, the effect of such peculiarities would -doubtless still remain, and the final result would not be more -trustworthy than before; but we should have a chance of -deciding whether such peculiarities really exist or not, -and also of determining what their nature may be. As an -instance in point, let me cite a case where, having only the -results of a single cycle, we can so arrange them as to appear -to indicate a cyclic association between sun-spots and rainfall, -while, when we give them year by year, such an association -is discredited, to say the least.</p> - -<p>The total rainfall at Port Louis, between the years 1855 -and 1868 inclusive, is as follows:—</p> - -<table class="p1" summary="Rainfall at Port Louis in 1855" style="max-width: 25em; margin: auto;"> - <tr> - <td class="tdc rpad">In</td> - <td class="tdc" colspan="2"><i>Rainfall.</i></td> - <td class="tdc"><i>Condition of Sun.</i></td></tr> - <tr> - <td class="tdc rpad">1855</td> - <td class="tdc">42·665</td> - <td class="tdc">inches</td> - <td class="tdl lpad">Sun-spot minimum.</td></tr> - <tr> - <td class="tdc rpad">1856</td> - <td class="tdc">46·230</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1857</td> - <td class="tdc">43·445</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1858</td> - <td class="tdc">35·506</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1859</td> - <td class="tdc">56·875</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1860</td> - <td class="tdc">45·166</td> - <td class="tdc">„</td> - <td class="tdl lpad">Sun-spot maximum.</td></tr> - <tr> - <td class="tdc rpad">1861</td> - <td class="tdc">68·733</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1862</td> - <td class="tdc">28·397</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1863</td> - <td class="tdc">33·420</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1864</td> - <td class="tdc">24·147</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1865</td> - <td class="tdc">44·730</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1866</td> - <td class="tdc">20·571</td> - <td class="tdc">„</td> - <td class="tdl lpad">Sun-spot minimum.</td></tr> - <tr> - <td class="tdc rpad">1867</td> - <td class="tdc">35·970</td> - <td class="tdc">„</td></tr> - <tr> - <td class="tdc rpad">1868</td> - <td class="tdc">64·180</td> - <td class="tdc">„</td></tr> -</table> - -<div id="ip_47" class="figcenter" style="max-width: 31.5em;"> - <img src="images/i_048.jpg" width="504" height="365" alt="" /></div> - -<p>I think no one, looking at these numbers as they stand, -can recognize any evidence of a cyclic tendency. If we -represent the rainfall by ordinates we get the accompanying<span class="pagenum"><a id="Page_48">48</a></span> -figure, which shows the rainfall for eighteen years, and again -I think it may be said that a very lively imagination is -required to recognize anything resembling that wave-like -undulation which the fundamental law of statistics requires -where a cycle is to be made out from a single oscillation. -Certainly the agreement between the broken curve of rainfall -and the sun-spot curve indicated by the waved dotted line is -not glaringly obvious. But when we strike an average for -the rainfall, in the way adopted by Mr. Jeula for shipwrecks, -how pleasantly is the theory of sun-spot influence illustrated -by the Port Louis rainfall! Here is the result, as quoted by -the high-priest of the new order of diviners, from the papers -by Mr. Meldrum:—</p> - -<table summary="Rainfall" style="max-width: 25em; margin: auto;"> - <tr> - <td class="tdl">Three minimum years—total rainfall</td> - <td class="tdl">133·340</td></tr> - <tr> - <td class="tdl">Three maximum years—total rainfall</td> - <td class="tdl">170·774</td></tr> - <tr> - <td class="tdl">Three minimum years—total rainfall</td> - <td class="tdl">120·721</td></tr> -</table> - -<p>Nothing could be more satisfactory, but nothing, I venture to -assert, more thoroughly inconsistent with the true method of -statistical research.</p> - -<p><span class="pagenum"><a id="Page_49">49</a></span> -May it not be that, underlying the broad results presented -by Mr. Jeula, there are similar irregularities?</p> - -<p>When we consider that the loss of ships depends, not only -on a cause so irregularly variable (to all seeming) as wind-storms, -but also on other matters liable to constant change, -as the variations in the state of trade, the occurrence of wars -and rumours of wars, special events, such as international -exhibitions, and so forth, we perceive that an even wider -range of survey is required to remove the effects of accidental -peculiarities in their case, than in the case of rainfall, -cyclones, or the like. I cannot but think, for instance, that -the total number of ships lost in divers ways during the -American war, and especially in its earlier years (corresponding -with two of the three maximum years of sun-spots) may -have been greater, not merely absolutely but relatively, than -in other years. I think it conceivable, again, that during -the depression following the great commercial panic of 1866 -(occurring at a time of minimum solar maculation, as already -noticed) the loss of ships may have been to some degree -reduced, relatively as well as absolutely. We know that -when trade is unusually active many ships have sailed, and -perhaps may still be allowed to sail (despite Mr. Plimsoll’s -endeavours), which should have been broken up; whereas -in times of trade depression the ships actually afloat are -likely to be, <em>on the average</em>, of a better class. So also, when, -for some special reason, passenger traffic at sea is abnormally -increased. I merely mention these as illustrative cases of -causes not (probably) dependent on sun-spots, which may -(not improbably) have affected the results examined by Mr. -Jeula. I think it possible that those results, if presented for -each year, would have indicated the operation of such -causes, naturally masked when sets of four years, four years, -and three years are taken instead of single years.</p> - -<p>I imagine that considerations such as these will have to -be taken into account and disposed of before it will be -unhesitatingly admitted that sun-spots have any great effect -in increasing the number of shipwrecks.</p> - -<p><span class="pagenum"><a id="Page_50">50</a></span> -The advocates of the doctrine of sun-spot influence—or, -perhaps it would be more correct to say, the advocates of -the endowment of sun-spot research—think differently on -these and other points. Each one of the somewhat doubtful -relations discussed above is constantly referred to by them -as a demonstrated fact, and a demonstrative proof of the -theory they advocate. For instance, Mr. Lockyer, in referring -to Meldrum’s statistical researches into the frequency of -cyclones, does not hesitate to assert that according to these -researches “the whole question of cyclones is merely a -question of solar activity, and that if we wrote down in one -column the number of cyclones in any given year, and in -another column the number of sun-spots in any given year, -there will be a strict relation between them—many sun-spots, -many hurricanes; few sun-spots, few hurricanes.” ... And -again, “Mr. Meldrum has since found” (not merely “has -since found reason to believe,” but definitely, “has since -found”) “that what is true of the storms which devastate the -Indian Ocean is true of the storms which devastate the West -Indies; and on referring to the storms of the Indian Ocean, -Mr. Meldrum points out that at those years where we have -been quietly mapping the sun-spot maxima, the harbours -were filled with wrecks, and vessels coming in disabled -from every part of the Indian Ocean.” Again, Mr. Balfour -Stewart accepts Mr. Jeula’s statistics confidently as demonstrating -that there are most shipwrecks during periods of -maximum solar activity. Nor are the advocates of the new -method of prediction at all doubtful as to the value of these -relations in affording the basis of a system of prediction. -They do not tell us precisely <em>how</em> we are to profit by the -fact, if fact it is, that cyclones and shipwrecks mark the time -of maximum solar maculation, and droughts and famine the -time of minimum. “If we can manage to get at these -things,” says Mr. Lockyer, “the power of prediction, that -power which would be the most useful one in meteorology, if -we could only get at it, would be within our grasp.” And Mr. -Balfour Stewart, in a letter to the <cite>Times</cite>, says, “If we are on<span class="pagenum"><a id="Page_51">51</a></span> -the track of a discovery which will in time enable us to foretell -the cycle of droughts, public opinion should demand -that the investigation be prosecuted with redoubled vigour -and under better conditions. If forewarned be forearmed, -then such research will ultimately conduce to the saving of -life both at times of maximum and minimum sun-spot -frequency.”</p> - -<p>If these hopes are really justified by the facts of the -case, it would be well that the matter should be as quickly -as possible put to the test. No one would be so heartless, -I think, as to reject, through an excess of scientific caution, -a scheme which might issue in the saving of many lives from -famine or from shipwreck. And on the other hand, no one, -I think, would believe so ill of his fellow-men as to suppose -for one moment that advantage could be taken of the sympathies -which have been aroused by the Indian famine, or -which may from time to time be excited by the record of -great disasters by sea and land, to advocate bottomless -schemes merely for purposes of personal advancement. We -must now, perforce, believe that those who advocate the -erection of new observatories and laboratories for studying -the physics of the sun, have the most thorough faith in the -scheme which they proffer to save our Indian population -from famine and our seamen from shipwreck.</p> - -<p>But they, on the other hand, should now also believe that -those who have described the scheme as entirely hopeless, do -really so regard it. If we exonerate them from the charge of -responding to an appeal for food by offering spectroscopes, -they in turn should exonerate us from the charge of denying -spectroscopes to the starving millions of India though -knowing well that the spectroscopic track leads straight to -safety.</p> - -<p>I must acknowledge I cannot for my own part see even -that small modicum of hope in the course suggested which -would suffice to justify its being followed. In my opinion, -one ounce of rice would be worth more (simply because it -would be worth something) than ten thousand tons of spectroscopes.<span class="pagenum"><a id="Page_52">52</a></span> -For what, in the first place, has been shown as to -the connection between meteorological phenomena and sun-spots? -Supposing we grant, and it is granting a great deal, -that all the cycles referred to have been made out. They -one and all affect averages only. The most marked among -them can so little be trusted in detail that while the maximum -of sun-spots agrees <em>in the main</em> with an excess or defect of -rain or wind, or of special rains with special winds, or the like, -the actual year of maximum may present the exact reverse.</p> - -<p>Of what use can it be to know, for instance, that the three -years of least solar maculation will probably give a rainfall -less than that for the preceding or following three years, if the -middle year of the three, when the spots are most numerous -of all, <em>may</em> haply show plenteous rainfall? Or it may be -the first of the three, or the last, which is thus well supplied, -while a defect in the other two, or in one of the others, -brings the total triennial rainfall below the average. What -provision could possibly be made under such circumstances -to meet a contingency which may occur in any one of three -years? or, at least, what provision could be made which would -prove nearly so effective as an arrangement which could -readily be made for keeping sufficient Government stores at -suitable stations (that is, never allowing such stores to fall at -the critical season in each year below a certain minimum), -and sending early telegraphic information of unfavourable -weather? Does any one suppose that the solar rice-grains are -better worth watching for such a purpose than the terrestrial -rice-grains, or that it is not well within the resources of -modern science and modern means of communication and -transport, to make sufficient preparation each year for a -calamity always possible in India? And be it noticed that -if, on the one hand, believers in solar safety from famine may -urge that, in thus objecting to their scheme, I am opposing -what might, in some year of great famine and small sun-spots, -save the lives of a greater number than would be saved by -any system of terrestrial watchfulness, I would point out, on -the other, that the solar scheme, if it means anything at all,<span class="pagenum"><a id="Page_53">53</a></span> -means special watchfulness at the minimum sun-spot season, -and general confidence (so far as famine is concerned) at the -season of maximum solar maculation; and that while as yet -nothing has been really proved about the connection between -sun-spots and famine, such confidence might prove to be a -very dangerous mistake.</p> - -<p>Supposing even it were not only proved that sun-spots -exert such and such effects, but that this knowledge can avail -to help us to measures of special precaution, how is the study -of the sun going to advance our knowledge? In passing, let -it be remarked that already an enormous number of workers -are engaged in studying the sun in every part of the world. -The sun is watched on every fine day, in every quarter of -the earth, with the telescope, analyzed with the spectroscope, -his prominences counted and measured, his surface photographed, -and so forth. What more ought to be or could be -done? But that is not the main point. If more could be -done, what could be added to our knowledge which would -avail in the way of prediction? “At present,” says Mr. -Balfour Stewart, “the problem has not been pursued on a -sufficiently large scale or in a sufficient number of places. If -the attack is to be continued, the skirmishers should give -way to heavy guns, and these should be brought to bear -without delay now that the point of attack is known.” In -other words, now that we know, according to the advocates -of these views, that meteorological phenomena follow roughly -the great solar-spot period, we should prosecute the attack -in this direction, in order to find out—what? Minor -periods, perhaps, with which meteorological phenomena may -still more roughly synchronize. Other such periods are -already known with which meteorological phenomena have -never yet been associated. New details of the sun’s surface? -No one has yet pretended that any of the details already -known, except the spots, affect terrestrial weather, and the -idea that peculiarities so minute as hitherto to have escaped -detection can do so, is as absurd, on the face of it, as the -supposition that minute details in the structure of a burning<span class="pagenum"><a id="Page_54">54</a></span> -coal, such details as could only be detected by close scrutiny, -can affect the general quality and effects of the heat transmitted -by the coal, as part of a large fire, to the further side -of a large room.</p> - -<p>Lastly, I would urge this general argument against a -theory which seems to me to have even less to recommend -it to acceptance than the faith in astrology.<a id="FNanchor_8" href="#Footnote_8" class="fnanchor">8</a> <em>If it requires,<span class="pagenum"><a id="Page_55">55</a></span> -as we are so strongly assured, the most costly observations, the -employment of the heaviest guns (and “great guns” are generally -expensive), twenty or thirty years of time, and the closest -scrutiny and research, to prove that sun-spots affect terrestrial -relations in a definite manner, effects so extremely difficult to -demonstrate cannot possibly be important enough to be worth -predicting.</em></p> - -<hr /> - -<p><span class="pagenum"><a id="Page_56">56</a></span></p> - -<div class="chapter"> -<h2><a id="NEW_WAYS_OF_MEASURING_THE_SUNS_DISTANCE"></a><i>NEW WAYS OF MEASURING THE SUN’S DISTANCE.</i></h2> -</div> - -<p class="in0">It is strange that the problem of determining the sun’s distance, -which for many ages was regarded as altogether -insoluble, and which even during later years had seemed -fairly solvable in but one or two ways, should be found, -on closer investigation, to admit of many methods of solution. -If astronomers should only be as fortunate hereafter -in dealing with the problem of determining the distances of -the stars, as they have been with the question of the sun’s -distance, we may hope for knowledge respecting the structure -of the universe such as even the Herschels despaired of our -ever gaining. Yet this problem of determining star-distances -does not seem more intractable, now, than the problem of -measuring the sun’s distance appeared only two centuries -ago. If we rightly view the many methods devised for dealing -with the easier task, we must admit that the more difficult—which, -by the way, is in reality infinitely the more interesting—cannot -be regarded as so utterly hopeless as, with -our present methods and appliances, it appears to be. True, -we know only the distances of two or three stars, approximately, -and have means of forming a vague opinion about the -distances of only a dozen others, or thereabouts, while at -distances now immeasurable lie six thousand stars visible to -the eye, and twenty millions within range of the telescope. -Yet, in Galileo’s time, men might have argued similarly -against all hope of measuring the proportions of the solar<span class="pagenum"><a id="Page_57">57</a></span> -system. “We know only,” they might have urged, “the -distance of the moon, our immediate neighbour,—beyond -her, at distances so great that hers, so far as we can judge, -is by comparison almost as nothing, lie the Sun and Mercury, -Venus and Mars; further away yet lie Jupiter and -Saturn, and possibly other planets, not visible to the naked -eye, but within range of that wonderful instrument, the -telescope, which our Galileo and others are using so successfully. -What hope can there be, when the exact measurement -of the moon’s distance has so fully taxed our powers of -celestial measurement, that we can ever obtain exact information -respecting the distances of the sun and planets? By -what method is a problem so stupendous to be attacked?” -Yet, within a few years of that time, Kepler had formed -already a rough estimate of the distance of the sun; in 1639, -young Horrocks pointed to a method which has since been -successfully applied. Before the end of the seventeenth -century Cassini and Flamsteed had approached the solution -of the problem more nearly, while Hailey had definitely formulated -the method which bears his name. Long before -the end of the eighteenth century it was certainly known -that the sun’s distance lies between 85 millions of miles and -98 millions (Kepler, Cassini, and Flamsteed had been unable -to indicate any superior limit). And lastly, in our own time, -half a score of methods, each subdivisible into several forms, -have been applied to the solution of this fundamental problem -of observational astronomy.</p> - -<p>I propose now to sketch some new and very promising -methods, which have been applied already with a degree of -success arguing well for the prospects of future applications -of the methods under more favourable conditions.</p> - -<p>In the first place, let us very briefly consider the methods -which had been before employed, in order that the proper -position of the new methods may be more clearly recognized.</p> - -<p>The plan obviously suggested at the outset for the solution -of the problem was simply to deal with it as a problem -of surveying. It was in such a manner that the moon’s<span class="pagenum"><a id="Page_58">58</a></span> -distance had been found, and the only difficulty in applying -the method to the sun or to any planet consisted in the -delicacy of the observations required. The earth being the -only surveying-ground available to astronomers in dealing -with this problem (in dealing with the problem of the stars’ -distances they have a very much wider field of operations), -it was necessary that a base-line should be measured on this -globe of ours,—large enough compared with our small selves, -but utterly insignificant compared with the dimensions of the -solar system. The diameter of the earth being less than -8000 miles, the longest line which the observers could take -for base scarcely exceeded 6000 miles; since observations -of the same celestial object at opposite ends of a diameter -necessarily imply that the object is in the horizon of <em>both</em> the -observing stations (for precisely the same reason that two -cords stretched from the ends of any diameter of a ball to a -distant point touch the ball at those ends). But the sun’s -distance being some 92 millions of miles, a base of 6000 -miles amounts to less than the 15,000th part of the distance -to be measured. Conceive a surveyor endeavouring to determine -the distance of a steeple or rock 15,000 feet, or nearly -three miles, from him, with a base-line <em>one foot</em> in length, -and you can conceive the task of astronomers who should -attempt to apply the direct surveying method to determine -the sun’s distance,—at least, you have one of their difficulties -strikingly illustrated, though a number of others remain -which the illustration does not indicate. For, after all, a -base one foot in length, though far too short, is a convenient -one in many respects: the observer can pass from one end -to the other without trouble—he looks at the distant object -under almost exactly the same conditions from each end, -and so forth. A base 6000 miles long for determining the -sun’s distance is too short in precisely the same degree, but -it is assuredly not so convenient a base for the observer. A -giant 36,000 miles high would find it as convenient as a surveyor -six feet high would find a one foot base-line; but -astronomers, as a rule, are less than 36,000 miles in height.<span class="pagenum"><a id="Page_59">59</a></span> -Accordingly the same observer cannot work at both ends of -the base-line, and they have to send out expeditions to -occupy each station. All the circumstances of temperature, -atmosphere, personal observing qualities, etc., are unlike at -the two ends of the base-line. The task of measuring the -sun’s distance directly is, in fact, at present beyond the -power of observational astronomy, wonderfully though its -methods have developed in accuracy.</p> - -<p>We all know how, by observations of Venus in transit, -the difficulty has been so far reduced that trustworthy results -have been obtained. Such observations belong to the -surveying method, only Venus’s distance is made the object -of measurement instead of the sun’s. The sun serves simply -as a sort of dial-plate, Venus’s position while in transit across -this celestial dial-plate being more easily measured than -when she is at large upon the sky. The devices by which -Halley and Delisle severally caused <em>time</em> to be the relation -observed, instead of position, do not affect the general -principle of the transit method. It remains dependent on -the determination of position. Precisely as by the change -of the <em>position</em> of the hands of a clock on the face we measure -<em>time</em>, so by the transit method, as Halley and Delisle respectively -suggested its use, we determine Venus’s position on -the sun’s face, by observing the difference of the time she -takes in crossing, or the difference of the time at which she -begins to cross, or passes off, his face.</p> - -<p>Besides the advantage of having a dial-face like the sun’s -on which thus to determine positions, the transit method -deals with Venus when at her nearest, or about 25 million -miles from us, instead of the sun at his greater distance of -from 90½ to 93½ millions of miles. Yet we do not get the -entire advantage of this relative proximity of Venus. For -the dial-face—the sun, that is—changes its position too—in -less degree than Venus changes hers, but still so much as -largely to reduce her seeming displacement. The sun being -further away as 92 to 25, is less displaced as 25 to 92. -Venus’s displacement is thus diminished by 25/92nds of its full<span class="pagenum"><a id="Page_60">60</a></span> -amount, leaving only 67/92nds. Practically, then, the advantage -of observing Venus, so far as distance is concerned, is the -same as though, instead of being at a distance of only 25 -million miles, her distance were greater as 92 to 67, giving -as her effective distance when in transit some 34,300,000 -miles.</p> - -<p>All the methods of observing Venus in transit are affected -in <em>this</em> respect. Astronomers were not content during the -recent transit to use Halley’s and Delisle’s two time methods -(which may be conveniently called the duration method and -the epoch method), but endeavoured to determine the -position of Venus on the sun’s face directly, both by observation -and by photography. The heliometer was the instrument -specially used for the former purpose; and as, in one -of the new methods to be presently described, this is the -most effective of all available instruments, a few words as to -its construction will not be out of place.</p> - -<p>The heliometer, then, is a telescope whose object-glass -(that is, the large glass at the end towards the object -observed) is divided into two halves along a diameter. -When these two halves are exactly together—that is, in the -position they had before the glass was divided—of course -they show any object to which they may be directed precisely -as they would have done before the glass was cut. But if, -without separating the straight edges of the two semicircular -glasses, one be made to slide along the other, the images -formed by the two no longer coincide.<a id="FNanchor_9" href="#Footnote_9" class="fnanchor">9</a> Thus, if we are -looking at the sun we see two overlapping discs, and by -continuing to turn the screw or other mechanism which -carries our half-circular glass past the other, the disc-images<span class="pagenum"><a id="Page_61">61</a></span> -of the sun may be brought entirely clear of each other. -Then we have two suns in the same field of view, seemingly -in contact, or nearly so. Now, if we have some means of -determining how far the movable half-glass has been carried -past the other to bring the two discs into apparently exact -contact, we have, in point of fact, a measure of the sun’s -apparent diameter. We can improve this estimate by carrying -back the movable glass till the images coincide again, -then further back till they separate the other way and finally -are brought into contact on that side. The entire range, -from contact on one side to contact on the other side, gives -twice the entire angular span of the sun’s diameter; and the -half of this is more likely to be the true measure of the -diameter, than the range from coincident images to contact -either way, simply because instrumental errors are likely to -be more evenly distributed over the double motion than over -the movement on either side of the central position. The -heliometer derived its name—which signifies sun-measurer—from -this particular application of the instrument.</p> - -<p>It is easily seen how the heliometer was made available -in determining the position of Venus at any instant during -transit. The observer could note what displacement of the -two half-glasses was necessary to bring the black disc of -Venus on one image of the sun to the edge of the other -image, first touching on the inside and then on the outside. -Then, reversing the motion, he could carry her disc to the -opposite edge of the other image of the sun, first touching -on the inside and then on the outside. Lord Lindsay’s -private expedition—one of the most munificent and also one -of the most laborious contributions to astronomy ever made—was -the only English expedition which employed the -heliometer, none of our public observatories possessing such -an instrument, and official astronomers being unwilling to ask -Government to provide instruments so costly. The Germans, -however, and the Russians employed the heliometer very -effectively.</p> - -<p>Next in order of proximity, for the employment of the<span class="pagenum"><a id="Page_62">62</a></span> -direct surveying method, is the planet Mars when he comes -into opposition (or on the same line as the earth and sun) in -the order</p> - -<p class="center"> -Sun____________________________Earth__________Mars, -</p> - -<p class="in0 p1">at a favourable part of his considerably eccentric orbit. His -distance then may be as small as 34½ millions of miles; and -we have in his case to make no reduction for the displacement -of the background on which his place is to be determined. -That background is the star sphere, his place being -measured from that of stars near which his apparent path on -the heavens carries him; and the stars are so remote that the -displacement due to a distance of six or seven thousand -miles between two observers on the earth is to all intents -and purposes nothing. The entire span of the earth’s orbit -round the sun, though amounting to 184 millions of miles, -is a mere point as seen from all save ten or twelve stars; -how utterly evanescent, then, the span of the earth’s globe—less -than the 23,000th part of her orbital range! Thus the -entire displacement of Mars due to the distance separating -the terrestrial observers comes into effect. So that, in comparing -the observation of Mars in a favourable opposition -with that of Venus in transit, we may fairly say that, so far -as surveying considerations are concerned, the two planets -are equally well suited for the astronomer’s purpose. -Venus’s less distance of 25 millions of miles is effectively -increased to 34⅓ millions by the displacement of the solar -background on which we see her when in transit; while -Mars’s distance of about 34½ millions of miles remains -effectively the same when we measure his displacement from -neighbouring fixed stars.</p> - -<p>But in many respects Mars is superior to Venus for the -purpose of determining the sun’s distance. Venus can only -be observed at her nearest when in transit, and transit lasts -but a few hours. Mars can be observed night after night -for a fortnight or so, during which his distance still remains -near enough to the least or opposition distance. Again,<span class="pagenum"><a id="Page_63">63</a></span> -Venus being observed on the sun, all the disturbing influences -due to the sun’s heat are at work in rendering the -observation difficult. The air between us and the sun at -such a time is disturbed by undulations due in no small -degree to the sun’s action. It is true that we have not, in -the case of Mars, any means of substituting time measures -or time determinations for measures of position, as we have -in Venus’s case, both with Halley’s and Delisle’s methods. -But to say the truth, the advantage of substituting these time -observations has not proved so great as was expected. -Venus’s unfortunate deformity of figure when crossing the -sun’s edge renders the determination of the exact moments of -her entry on the sun’s face and of her departure from it by no -means so trustworthy as astronomers could wish. On the -whole, Mars would probably have the advantage even without -that point in his favour which has now to be indicated.</p> - -<p>Two methods of observing Mars for determining the -sun’s distance are available, both of which, as they can be -employed in applying one of the new methods, may -conveniently be described at this point.</p> - -<p>An observer far to the north of the earth’s equator sees -Mars at midnight, when the planet is in opposition, displaced -somewhat to the south of his true position—that is, of the -position he would have as supposed to be seen from the -centre of the earth. On the other hand, an observer far to -the south of the equator sees Mars displaced somewhat to -the north of his true position. The difference may be compared -to different views of a distant steeple (projected, let -us suppose, against a much more remote hill), from the -uppermost and lowermost windows of a house corresponding -to the northerly and southerly stations on the earth, and -from a window on the middle story corresponding to a view -of Mars from the earth’s centre. By ascertaining the displacement -of the two views of Mars obtained from a station -far to the north and another station far to the south, the -astronomer can infer the distance of the planet, and thence -the dimensions of the solar system. The displacement is<span class="pagenum"><a id="Page_64">64</a></span> -determinable by noticing Mars’s position with respect to -stars which chance to be close to him. For this purpose the -heliometer is specially suitable, because, having first a view -of Mars and some companion stars as they actually are -placed, the observer can, by suitably displacing the movable -half-glass, bring the star into apparent contact with the -planet, first on one side of its disc, and then on the other -side—the mean of the two resulting measures giving, of -course, the distance between the star and the centre of the -disc.</p> - -<p>This method requires that there shall be two observers, -one at a northern station, as Greenwich, or Paris, or Washington, -the other at a southern station, as Cape Town, -Cordoba, or Melbourne. The base-line is practically a -north-and-south line; for though the two stations may not -lie in the same, or nearly the same, longitude, the displacement -determined is in reality that due to their difference of -latitude only, a correction being made for their difference -of longitude.</p> - -<p>The other method depends, not on displacement of -two observers north and south, or difference of latitude, but -on displacement east and west. Moreover, it does not -require that there shall be two observers at stations far -apart, but uses the observations made at one and the same -stations at different times. The earth, by turning on her -axis, carries the observer from the west to the east of an -imaginary line joining the earth’s centre and the centre of -Mars. When on the west of that line, or in the early evening, -he sees Mars displaced towards the east of the planet’s true -position. After nine or ten hours the observer is carried as -far to the east of that line, and sees Mars displaced towards -the west of his true position. Of course Mars has moved in -the interval. He is, in fact, in the midst of his retrograde -career. But the astronomer knows perfectly well how to -take that motion into account. Thus, by observing the two -displacements, or the total displacement of Mars from east -to west on account of the earth’s rotation, one and the same<span class="pagenum"><a id="Page_65">65</a></span> -observer can, in the course of a single favourable night, -determine the sun’s distance. And in passing, it may be -remarked that this is the only general method of which so -much can be said. By some of the others an astronomer -can, indeed, estimate the sun’s distance without leaving his -observatory—at least, theoretically he can do so. But many -years of observation would be required before he would have -materials for achieving this result. On the other hand, one -good pair of observations of Mars, in the evening and in the -morning, from a station near the equator, would give a very -fair measure of the sun’s distance. The reason why the -station should be near the equator will be manifest, if we -consider that at the poles there would be no displacement -due to rotation; at the equator the observer would be carried -round a circle some twenty-five thousand miles in circumference; -and the nearer his place to the equator the larger the -circle in which he would be carried, and (<i xml:lang="la" lang="la">cæteris paribus</i>) the -greater the evening and morning displacement of the planet.</p> - -<p>Both these methods have been successfully applied to -the problem of determining the sun’s distance, and both have -recently been applied afresh under circumstances affording -exceptionally good prospects of success, though as yet the -results are not known.</p> - -<p>It is, however, when we leave the direct surveying method -to which both the observations of Venus in transit and Mars -in opposition belong (in all their varieties), that the most -remarkable, and, one may say, unexpected methods of determining -the sun’s distance present themselves. Were not my -subject a wide one, I would willingly descant at length on the -marvellous ingenuity with which astronomers have availed -themselves of every point of vantage whence they might -measure the solar system. But, as matters actually stand, I -must be content to sketch these other methods very roughly, -only indicating their characteristic features.</p> - -<p>One of them is in some sense related to the method by -actual survey, only it takes advantage, not of the earth’s -dimensions, but of the dimensions of her orbit round the<span class="pagenum"><a id="Page_66">66</a></span> -common centre of gravity of herself and the moon. This -orbit has a diameter of about six thousand miles; and as -the earth travels round it, speeding swiftly onwards all the -time in her path round the sun, the effect is the same as -though the sun, in his apparent circuit round the earth, were -constantly circling once in a lunar month around a small -subordinate orbit of precisely the same size and shape as -that small orbit in which the earth circuits round the moon’s -centre of gravity. He appears then sometimes displaced -about 3000 miles on one side, sometimes about 3000 miles -on the other side of the place which he would have if our -earth were not thus perturbed by the moon. But astronomers -can note each day where he is, and thus learn by how -much he seems displaced from his mean position. Knowing -that his greatest displacement corresponds to so many miles -exactly, and noting what it seems to be, they learn, in fact, -how large a span of so many miles (about 3000) looks at the -sun’s distance. Thus they learn the sun’s distance precisely as -a rifleman learns the distance of a line of soldiers when he has -ascertained their apparent size—for only at a certain distance -can an object of known size have a certain apparent size.</p> - -<p>The moon comes in, in another way, to determine the -sun’s distance for us. We know how far away she is from -the earth, and how much, therefore, she approaches the sun -when new, and recedes from him when full. Calling this -distance, roughly, a 390th part of the sun’s, her distance -from him when new, her mean distance, and her distance -from him when full, are as the numbers 389, 390, 391. Now, -these numbers do not quite form a continued proportion, -though they do so very nearly (for 389 is to 390 as 390 to -391-1/400). If they were in exact proportion, the sun’s disturbing -influence on the moon when she is at her nearest would -be exactly equal to his disturbing influence on the moon -when at her furthest from him—or generally, the moon would -be exactly as much disturbed (on the average) in that half of -her path which lies nearer to the sun as in that half which -lies further from him. As matters are, there is a slight<span class="pagenum"><a id="Page_67">67</a></span> -difference. Astronomers can measure this difference; and -measuring it, they can ascertain what the actual numbers are -for which I have roughly given the numbers 389, 390, and -391; in other words, they can ascertain in what degree the -sun’s distance exceeds the moon’s. This is equivalent to -determining the sun’s distance, since the moon’s is already -known.</p> - -<p>Another way of measuring the sun’s distance has been -“favoured” by Jupiter and his family of satellites. Few -would have thought, when Römer first explained the delay -which occurs in the eclipse of these moons while Jupiter is -further from us than his mean distance, that that explanation -would lead up to a determination of the sun’s distance. But -so it happened. Römer showed that the delay is not in the -recurrence of the eclipses, but in the arrival of the news of -these events. From the observed time required by light to -traverse the extra distance when Jupiter is nearly at his -furthest from us, the time in which light crosses the distance -separating us from the sun is deduced; whence, if that distance -has been rightly determined, the velocity of light can be inferred. -If this velocity is directly measured in any way, and -found not to be what had been deduced from the adopted -measure of the sun’s distance, the inference is that the sun’s -distance has been incorrectly determined. Or, to put the -matter in another way, we know exactly how many minutes -and seconds light takes in travelling to us from the sun; if, -therefore, we can find out how fast light travels we know -how far away the sun is.</p> - -<p>But who could hope to measure a velocity approaching -200,000 miles in a second? At a first view the task seems -hopeless. Wheatstone, however, showed how it might be -accomplished, measuring by his method the yet greater -velocity of freely conducted electricity. Foucault and Fizeau -measured the velocity of light; and recently Cornu has made -more exact measurements. Knowing, then, how many miles -light travels in a second, and in how many seconds it comes -to us from the sun, we know the sun’s distance.</p> - -<p><span class="pagenum"><a id="Page_68">68</a></span> -The first of the methods which I here describe as -new methods must next be considered. It is one which -Leverrier regards as the method of the future. In fact, so -highly does he esteem it, that, on its account, he may almost -be said to have refused to sanction in any way the French -expeditions for observing the transit of Venus in 1874.</p> - -<p>The members of the sun’s family perturb each other’s -motions in a degree corresponding with their relative mass, -compared with each other and with the sun. Now, it can be -shown (the proof would be unsuitable to these pages,<a id="FNanchor_10" href="#Footnote_10" class="fnanchor">10</a> but -I have given it in my treatise on “The Sun”) that no change -in our estimate of the sun’s distance affects our estimate of -his mean density as compared with the earth’s. His substance -has a mean density equal to one-fourth of the earth’s, whether -he be 90 millions or 95 millions of miles from us, or indeed -whether he were ten millions or a million million miles from -us (supposing for a moment our measures did not indicate -his real distance more closely). We should still deduce from<span class="pagenum"><a id="Page_69">69</a></span> -calculation the same unvarying estimate of his mean density. -It follows that the nearer any estimate of his distance places -him, and therefore the smaller it makes his estimated -volume, the smaller also it makes his estimated mass, and -in precisely the same degree. The same is true of the -planets also. We determine Jupiter’s mass, for example (at -least, this is the simplest way), by noting how he swerves -his moons at their respective (estimated) distances. If we -diminish our estimate of their distances, we diminish at the -same time our estimate of Jupiter’s attractive power, and in -such degree, it may be shown (see note), as precisely to -correspond with our changed estimate of his size, leaving our -estimate of his mean density unaltered. And the same is -true for all methods of determining Jupiter’s mass. Suppose, -then, that, adopting a certain estimate of the scale of the -solar system, we find that the resulting estimate of the masses -of the planets and of the sun, <em>as compared with the earth’s -mass</em>, from their observed attractive influences on bodies -circling around them or passing near them, accords with -their estimated perturbing action as compared with the -earth’s,—then we should infer that our estimate of the sun’s -distance or of the scale of the solar system was correct. -But suppose it appeared, on the contrary, that the earth took -a larger or a smaller part in perturbing the planetary system -than, according to our estimate of her relative mass, she -should do,—then we should infer that the masses of the -other members of the system had been overrated or underrated; -or, in other words, that the scale of the solar system -had been overrated or underrated respectively. Thus we -should be able to introduce a correction into our estimate of -the sun’s distance.</p> - -<p>Such is the principle of the method by which Leverrier -showed that in the astronomy of the future the scale of the -solar system may be very exactly determined. Of course, the -problem is a most delicate one. The earth plays, in truth, -but a small part in perturbing the planetary system, and her -influence can only be distinguished satisfactorily (at present,<span class="pagenum"><a id="Page_70">70</a></span> -at any rate) in the case of the nearer members of the solar -family. Yet the method is one which, unlike others, will have -an accumulative accuracy, the discrepancies which are to test -the result growing larger as time proceeds. The method has -already been to some extent successful. It was, in fact, by -observing that the motions of Mercury are not such as can -be satisfactorily explained by the perturbations of the earth -and Venus according to the estimate of relative masses -deducible from the lately discarded value of the sun’s distance, -that Leverrier first set astronomers on the track of -the error affecting that value. He was certainly justified in -entertaining a strong hope that hereafter this method will -be exceedingly effective.</p> - -<p>We come next to a method which promises to be more -quickly if not more effectively available.</p> - -<p>Venus and Mars approach the orbit of our earth more -closely than any other planets, Venus being our nearest -neighbour on the one side, and Mars on the other. Looking -beyond Venus, we find only Mercury (and the mythical Vulcan), -and Mercury can give no useful information respecting -the sun’s distance. He could scarcely do so even if we -could measure his position among the stars when he is at -his nearest, as we can that of Mars; but as he can only then -be fairly seen when he transits the sun’s face, and as the sun -is nearly as much displaced as Mercury by change in the -observer’s station, the difference between the two displacements -is utterly insufficient for accurate measurement. But, -when we look beyond the orbit of Mars, we find certain -bodies which are well worth considering in connection with -the problem of determining the sun’s distance. I refer to -the asteroids, the ring of small planets travelling between -the paths of Mars and Jupiter, but nearer (on the whole<a id="FNanchor_11" href="#Footnote_11" class="fnanchor">11</a>) -to the path of Mars than to that of Jupiter.</p> - -<p><span class="pagenum"><a id="Page_71">71</a></span> -The asteroids present several important advantages over -even Mars and Venus.</p> - -<p>Of course, none of the asteroids approach so near to the -earth as Mars at his nearest. His least distance from the sun -being about 127 million miles, and the earth’s mean distance -about 92 millions, with a range of about a million and -a half on either side, owing to the eccentricity of her orbit, it -follows that he <em>may</em> be as near as some 35 million miles -(rather less in reality) from the earth when the sun, earth, -and Mars are nearly in a straight line and in that order. -The least distance of any asteroid from the sun amounts to -about 167 million miles, so that their least distance from the -earth cannot at any time be less than about 73,500,000 -miles, even if the earth’s greatest distance from the sun -corresponded with the least distance of one of these closely -approaching asteroids. This, by the way, is not very far from -being the case with the asteroid Ariadne, which comes within -about 169 million miles of the sun at her nearest, her place -of nearest approach being almost exactly in the same direction -from the sun as the earth’s place of greatest recession, -reached about the end of June. So that, whenever it so -chances that Ariadne comes into opposition in June, or that -the sun, earth, and Ariadne are thus placed—</p> - -<p class="center"> -Sun________Earth________Ariadne, -</p> - -<p class="p1 in0">Ariadne will be but about 75,500,000 miles from the earth. -Probably no asteroid will ever be discovered which approaches -the earth much more nearly than this; and this -approach, be it noticed, is not one which can occur in the -case of Ariadne except at very long intervals.</p> - -<p>But though we may consider 80 millions of miles as a -fair average distance at which a few of the most closely -approaching asteroids may be observed, and though this<span class="pagenum"><a id="Page_72">72</a></span> -distance seems very great by comparison with Mars’s occasional -opposition distance of 35 million miles, yet there are -two points in which asteroids have the advantage over -Mars. First, they are many, and several among them can -be observed under favourable circumstances; and in the -multitude of observations there is safety. In the second -place, which is the great and characteristic good quality of -this method of determining the sun’s distance, they do not -present a disc, like the planet Mars, but a small star-like -point. When we consider the qualities of the heliometric -method of measuring the apparent distance between -celestial objects, the advantage of points of light over discs -will be obvious. If we are measuring the apparent distance -between Mars and a star, we must, by shifting the movable -object-glass, bring the star’s image into apparent contact -with the disc-image of Mars, first on one side and then on -the other, taking the mean for the distance between the -centres. Whereas, when we determine the distance between -a star and an asteroid, we have to bring two star-like points -(one a star, the other the asteroid) into apparent coincidence. -We can do this in two ways, making the result so much the -more accurate. For consider what we have in the field of -view when the two halves of the object-glass coincide. -There is the asteroid and close by there is the star whose -distance we seek to determine in order to ascertain the -position of the asteroid on the celestial sphere. When the -movable half is shifted, the two images of star and asteroid -separate; and by an adjustment they can be made to -separate along the line connecting them. Suppose, then, -we first make the movable image of the asteroid travel away -from the fixed image (meaning by movable and fixed images, -respectively, those given by the movable and fixed halves of -the object-glass), towards the fixed image of the star—the -two points, like images, being brought into coincidence, we -have the measure of the distance between star and asteroid. -Now reverse the movement, carrying back the movable images -of the asteroid and star till they coincide again with their<span class="pagenum"><a id="Page_73">73</a></span> -fixed images. This movement gives us a second measure -of the distance, which, however, may be regarded as only a -reversed repetition of the preceding. But now, carrying on -the reverse motion, the moving images of star and asteroid -separate from their respective fixed images, the moving -image of the star drawing near to the fixed image of the -asteroid and eventually coinciding with it. Here we have a -third measure of the distance, which is independent of the -two former. Reversing the motion, and carrying the moving -images to coincidence with the fixed images, we have a -fourth measure, which is simply the third reversed. These -four measures will give a far more satisfactory determination -of the true apparent distance between the star and the -asteroid than can, under any circumstances, be obtained in -the case of Mars and a star. Of course, a much more exact -determination is required to give satisfactory measures of the -asteroid’s real distance from the earth in miles, for a much -smaller error would vitiate the estimate of the asteroid’s -distance than would vitiate to the same degree the estimate -of Mars’s distance: for the apparent displacements of the -asteroid as seen either from Northern and Southern stations, -or from stations east and west of the meridian, are very much -less than in the case of Mars, owing to his great proximity. -But, on the whole, there are reasons for believing that the advantage -derived from the nearness of Mars is almost entirely -counterbalanced by the advantage derived from the neatness -of the asteroid’s image. And the number of asteroids, with -the consequent power of repeating such measurements many -times for each occasion on which Mars has been thus observed, -seem to make the asteroids—so long regarded as -very unimportant members of the solar system—the bodies -from which, after all, we shall gain our best estimate of the -sun’s distance; that is, of the scale of the solar system.</p> - -<div class="tb">* <span class="in2">* </span><span class="in2">* </span><span class="in2">* </span><span class="in2">*</span></div> - -<p>Since the above pages were written, the results deduced -from the observations made by the British expeditions for<span class="pagenum"><a id="Page_74">74</a></span> -observing the transit of December 9, 1874, have been announced -by the Astronomer Royal. It should be premised -that they are not the results deducible from the entire series -of British observations, for many of them can only be used -effectively in combination with observations made by other -nations. For instance, the British observations of the duration -of the transit as seen from Southern stations are only -useful when compared with observations of the duration of -the transit as seen from Northern stations, and no British -observations of this kind were taken at Northern stations, or -could be taken at any of the British Northern stations -except one, where chief reliance was placed on photographic -methods. The only British results as yet “worked up” are -those which are of themselves sufficient, theoretically, to indicate -the sun’s distance, viz., those which indicated the epochs -of the commencement of transit as seen from Northern and -Southern stations, and those which indicated the epochs of -the end of transit as seen from such stations. The Northern -and Southern epochs of commencement compared together -suffice <em>of themselves</em> to indicate the sun’s distance; so also -do the epochs of the end of transit suffice <em>of themselves</em> for -that purpose. Such observations belong to the Delislean -method, which was the subject of so much controversy -for two or three years before the transit took place. -Originally it had been supposed that only observations by -that method were available, and the British plans were -formed upon that assumption. When it was shown that this -assumption was altogether erroneous, there was scarcely time -to modify the British plans so that of themselves they -might provide for the other or Halleyan method. But the -Southern stations which were suitable for that method were -strengthened; and as other nations, especially America and -Russia, occupied large numbers of Northern stations, the -Halleyan method was, in point of fact, effectually provided -for—a fortunate circumstance, as will presently be seen.</p> - -<p>The British operations, then, thus far dealt with, were -based on Delisle’s method; and as they were carried out<span class="pagenum"><a id="Page_75">75</a></span> -with great zeal and completeness, we may consider that -the result affords an excellent test of the qualities of this -method, and may supply a satisfactory answer to the questions -which were under discussion in 1872–74. Sir George -Airy, indeed, considers that the zeal and completeness with -which the British operations were carried out suffice to set -the result obtained from them above all others. But this -opinion is based rather on personal than on strictly scientific -grounds. It appears to me that the questions to be -primarily decided are whether the results are in satisfactory -agreement (i) <i xml:lang="la" lang="la">inter se</i> and (ii) with the general tenor of former -researches. In other words, while the Astronomer Royal -considers that the method and the manner of its application -must be considered so satisfactory that the results are to be -accepted unquestionably, it appears to me that the results -must be carefully questioned (as it were) to see whether the -method, and the observations by it, are satisfactory. In -the first place, the result obtained from Northern and -Southern observations of the commencement ought to agree -closely with the result obtained from Northern and Southern -observations of the end of transit. Unfortunately, they -differ rather widely. The sun’s distance by the former -observations comes out about one million miles greater -than the distance determined by the latter observations.</p> - -<p>This should be decisive, one would suppose. But it is -not all. The mean of the entire series of observations by -Delisle’s method comes out nearly one million miles greater -than the mean deduced by Professor Newcomb from many -entire series of observations by six different methods, all of -which may fairly be regarded as equal in value to Delisle’s, -while three are regarded by most astronomers as unquestionably -superior to it. Newcomb considers the probable -limits of error in his evaluation from so many combined -series of observations to be about 100,000 miles. Sir G. -Airy will allow no wider limits of error for the result of the -one series his observers have obtained than 200,000 miles. -Thus the greatest value admitted by Newcomb falls short<span class="pagenum"><a id="Page_76">76</a></span> -of the least value admitted by Sir G. Airy, by nearly 700,000 -miles.</p> - -<p>The obvious significance of this result should be, one -would suppose, that Delisle’s method is not quite so effective -as Sir G. Airy supposed; and the wide discordance between -the several results, of which the result thus deduced is the -mean, should prove this, one would imagine, beyond all -possibility of question. The Astronomer Royal thinks -differently, however. In his opinion, the wide difference -between his result and the mean of all the most valued -results by other astronomers, indicates the superiority of -Delisle’s method, not its inadequacy to the purpose for -which it has been employed.</p> - -<p>Time will shortly decide which of these views is correct; -but, for my own part, I do not hesitate to express my own -conviction that the sun’s distance lies very near the limits -indicated by Newcomb, and therefore is several hundred -thousand miles less than the minimum distance allowed by -the recently announced results.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_77">77</a></span></p> - -<div class="chapter"> -<h2><a id="DRIFTING_LIGHT-WAVES"></a>DRIFTING LIGHT-WAVES.</h2> -</div> - -<p class="in0">The method of measuring the motion of very swiftly -travelling bodies by noting changes in the light-waves which -reach us from them—one of the most remarkable methods -of observation ever yet devised by man—has recently been -placed upon its trial, so to speak; with results exceedingly -satisfactory to the students of science who had accepted the -facts established by it. The method will not be unfamiliar -to many of my readers. The principle involved was first -noted by M. Doppler, but not in a form which promised -any useful results. The method actually applied appears -to have occurred simultaneously to several persons, as well -theorists as observers. Thus Secchi claimed in March, -1868, to have applied it though unsuccessfully; Huggins -in April, 1868, described his successful use of the method. -I myself, wholly unaware that either of these observers was -endeavouring to measure celestial motions by its means, -described the method, in words which I shall presently -quote, in the number of <cite>Fraser’s Magazine</cite> for January, -1868, two months before the earliest enunciation of its -nature by the physicists just named.</p> - -<p>It will be well briefly to describe the principle of this -interesting method, before considering the attack to which it -has been recently subjected, and its triumphant acquittal -from defects charged against it. This brief description will -not only be useful to those readers who chance not to -be acquainted with the method, but may serve to remove -objections which suggest themselves, I notice, to many who<span class="pagenum"><a id="Page_78">78</a></span> -have had the principle of the method imperfectly explained -to them.</p> - -<p>Light travels from every self-luminous body in waves -which sweep through the ether of space at the rate of -185,000 miles per second. The whole of that region of -space over which astronomers have extended their survey, -and doubtless a region many millions of millions of times -more extended, may be compared to a wave-tossed sea, only -that instead of a wave-tossed surface, there is wave-tossed -space. At every point, through every point, along every -line, athwart every line, myriads of light-waves are at all -times rushing with the inconceivable velocity just mentioned.</p> - -<p>It is from such waves that we have learned all we know -about the universe outside our own earth. They bring to -our shores news from other worlds, though the news is not -always easy to decipher.</p> - -<p>Now, seeing that we are thus immersed in an ocean, -athwart which infinite series of waves are continually -rushing, and moreover that we ourselves, and every one of -the bodies whence the waves proceed either directly or after -reflection, are travelling with enormous velocity through this -ocean, the idea naturally presents itself that we may learn -something about these motions (as well as about the bodies -themselves whence they proceed), by studying the aspect of -the waves which flow in upon us in all directions.</p> - -<p>Suppose a strong swimmer who knew that, were he at -rest, a certain series of waves would cross him at a particular -rate—ten, for instance, in a minute—were to notice that -when he was swimming directly facing them, eleven passed -him in a minute: he would be able at once to compare -his rate of swimming with the rate of the waves’ motion. -He would know that while ten waves had passed him on -account of the waves’ motion, he had by his own motion -caused yet another wave to pass him, or in other words, had -traversed the distance from one wave-crest to the next -Thus he would know that his rate was one-tenth that of -the waves. Similarly if, travelling the same way as the waves,<span class="pagenum"><a id="Page_79">79</a></span> -he found that only nine passed him in a minute, instead -of ten.</p> - -<p>Again, it is not difficult to see that if an observer were at -rest, and a body in the water, which by certain motions -produced waves, were approaching or receding from the -observer, the waves would come in faster in the former case, -slower in the latter, than if the body were at rest. Suppose, -for instance, that some machinery at the bows of a ship -raised waves which, if the ship were at rest, would travel -along at the rate of ten a minute past the observer’s station. -Then clearly, if the ship approached him, each successive -wave would have a shorter distance to travel, and so would -reach him sooner than it otherwise would have done. -Suppose, for instance, the ship travelled one-tenth as fast as -the waves, and consider ten waves proceeding from her -bows—the first would have to travel a certain distance -before reaching the observer; the tenth, starting a minute -later, instead of having to travel the same distance, would -have to travel this distance diminished by the space over -which the ship had passed in one minute (which the -wave itself passes over in the tenth of a minute); instead, -then, of reaching the observer one minute after the other, it -would reach him nine-tenths of a minute after the first. -Thus it would seem to him as though the waves were -coming in faster than when the ship was at rest, in the -proportion of ten to nine, though in reality they would -be travelling at the same rate as before, only arriving in -quicker succession, because of the continual shortening of -the distance they had to travel, on account of the ship’s -approach. If he knew precisely how fast they <em>would</em> arrive -if the ship were at rest, and determined precisely how fast -they <em>did</em> arrive, he would be able to determine at once -the rate of the ship’s approach, at least the proportion -between her rate and the rate of the waves’ motion. -Similarly if, owing to the ship’s recession, the apparent rate -of the waves’ motion were reduced, it is obvious that the -actual change in the wave motion would not be a difference<span class="pagenum"><a id="Page_80">80</a></span> -of rate; but, in the case of the approaching ship, the -breadth from crest to crest would be reduced, while in -the case of a receding ship the distance from crest to crest -would be increased.</p> - -<p>If the above explanation should still seem to require -closer attention than the general reader may be disposed to -give, the following, suggested by a friend of mine—a very -skilful mathematician—will be found still simpler: Suppose -a stream to flow quite uniformly, and that at one place -on its banks an observer is stationed, while at another higher -up a person throws corks into the water at regular intervals, -say ten corks per minute; then these will float down and -pass the other observer, wherever he may be, at the rate of -ten per minute, <em>if</em> the cork-thrower is at rest. But if he -saunters either up-stream or down-stream, the corks will no -longer float past the other at the exact rate of ten per minute. -If the thrower is sauntering down-stream, then, between -throwing any cork and the next, he has walked a certain -way down, and the tenth cork, instead of having to travel -the same distance as the first before reaching the observer, -has a shorter distance to travel, and so reaches that observer -sooner. Or in fact, which some may find easier to see, this -cork will be nearer to the first cork than it would have been -if the thrower had remained still. The corks will lie at -equal distances from each other, but these equal distances -will be less than they would have been if the observer had -been at rest. If, on the contrary, the cork-thrower saunters -up-stream, the corks will be somewhat further apart than if -he had remained at rest. And supposing the observer to -know beforehand that the corks would be thrown in at the -rate of ten a minute, he would know, if they passed him at a -greater rate than ten a minute (or, in other words, at a less -distance from each other than the stream traversed in the -tenth of a minute), that the cork-thrower was travelling -down-stream or approaching him; whereas, if fewer than ten -a minute passed him, he would know that the cork-thrower -was travelling away from him, or up-stream. But also, if the<span class="pagenum"><a id="Page_81">81</a></span> -cork-thrower were at rest, and the observer moved up-stream—that -is, towards him—the corks would pass him at a -greater rate than ten a minute; whereas, if the observer were -travelling down-stream, or from the thrower, they would -pass him at a slower rate. If both were moving, it is easily -seen that if their movement brought them nearer together, -the number of corks passing the observer per minute would -be increased, whereas if their movements set them further -apart, the number passing him per minute would be -diminished.</p> - -<p>These illustrations, derived from the motions of water, -suffice in reality for our purpose. The waves which are -emitted by luminous bodies in space travel onwards like the -water-waves or the corks of the preceding illustrations. If -the body which emits them is rapidly approaching us, the -waves are set closer together or narrowed; whereas, if the -body is receding, they are thrown further apart or broadened. -And if we can in any way recognize such narrowing or -broadening of the light-waves, we know just as certainly that -the source of light is approaching us or receding from us (as -the case may be) as our observer in the second illustration -would know from the distance between the corks whether -his friend, the cork-thrower, was drawing near to him or -travelling away from him.</p> - -<p>But it may be convenient to give another illustration, -drawn from waves, which, like those of light, are not themselves -discernible by our senses—I refer to those aerial -waves of compression and rarefaction which produce what -we call sound. These waves are not only in this respect -better suited than water-waves to illustrate our subject, but -also because they travel in all directions through aerial space, -not merely along a surface. The waves which produce a -certain note, that is, which excite in our minds, through the -auditory nerve, the impression corresponding to a certain -tone, have a definite length. So long as the observer, and a -source of sound vibrating in one particular period, remain -both in the same place, the note is unchanged in tone, though<span class="pagenum"><a id="Page_82">82</a></span> -it may grow louder or fainter according as the vibrations -increase or diminish in amplitude. But if the source of -sound is approaching the hearer, the waves are thrown closer -together and the sound is rendered more acute (the longer -waves giving the deeper sound); and, on the other hand, if -the source of sound is receding from the hearer, the waves -are thrown further apart and the sound is rendered graver. -The <em>rationale</em> of these changes is precisely the same as that -of the changes described in the preceding illustrations. It -might, perhaps, appear that in so saying we were dismissing -the illustration from sound, at least as an independent one, -because we are explaining the illustration by preceding illustrations. -But in reality, while there is absolutely nothing -new to be said respecting the increase and diminution of -distances (as between the waves and corks of the preceding -illustration), the illustration from sound has the immense -advantage of admitting readily of experimental tests. It is -necessary only that the rate of approach or recession should -bear an appreciable proportion to the rate at which sound -travels. For waves are shortened or lengthened by approach -or recession by an amount which bears to the entire length -of the wave the same proportion which the rate of approach -or recession bears to the rate of the wave’s advance. Now -it is not very difficult to obtain rates of approach or recession -fairly comparable with the velocity of sound—about 364 -yards per second. An express train at full speed travels, let -us say, about 1800 yards per minute, or 30 yards per second. -Such a velocity would suffice to reduce all the sound-waves -proceeding from a bell or whistle upon the engine, by about -one-twelfth part, for an observer at rest on a station platform -approached by the engine. On the contrary, after the engine -had passed him, the sound-waves proceeding from the same -bell or whistle would be lengthened by one-twelfth. The -difference between the two tones would be almost exactly -three semitones. If the hearer, instead of being on a platform, -were in a train carried past the other at the same rate, -the difference between the tone of the bell in approaching<span class="pagenum"><a id="Page_83">83</a></span> -and its tone in receding would be about three tones. It -would not be at all difficult so to arrange matters, that while -two bells were sounding the same note—<i>Mi</i>, let us say—one -bell on one engine the other on the other, a traveller by one -should hear his own engine’s bell, the bell of the approaching -engine, and the bell of the same engine receding, as the -three notes—<i>Do</i>—<i>Mi</i>—<i>Sol</i>, whose wave-lengths are as the -numbers 15, 12, and 10. We have here differences very -easily to be recognized even by those who are not musicians. -Every one who travels much by train must have noticed how -the tone of a whistle changes as the engine sounding it travels -past. The change is not quite sharp, but very rapid, because -the other engine does not approach with a certain velocity -up to a definite moment and then recede with the same -velocity. It could only do this by rushing through the hearer, -which would render the experiment theoretically more exact -but practically unsatisfactory. As it rushes past instead of -through him, there is a brief time during which the rate of -approach is rapidly being reduced to nothing, followed by -a similarly brief time during which the rate of recession -gradually increases from nothing up to the actual rate of the -engines’ velocities added together.<a id="FNanchor_12" href="#Footnote_12" class="fnanchor">12</a> The change of tone -may be thus illustrated:—</p> - -<div id="ip_83" class="figcenter" style="max-width: 31.25em;"> - <img src="images/i_083.jpg" width="500" height="54" alt="" /></div> - -<p>A B representing the sound of the approaching whistle, B C -representing the rapid degradation of sound as the engine -rushes close past the hearer, and C D representing the sound -of the receding whistle. When a bell is sounded on the<span class="pagenum"><a id="Page_84">84</a></span> -engine, as in America, the effect is better recognized, as I -had repeated occasion to notice during my travels in that -country. Probably this is because the tone of a bell is in -any case much more clearly recognized than the tone of a -railway whistle. The change of tone as a clanging bell is -carried swiftly past (by the combined motions of both trains) -is not at all of such a nature as to require close attention for -its detection.</p> - -<p>However, the apparent variation of sound produced by -rapid approach or recession has been tested by exact experiments. -On a railway uniting Utrecht and Maarsen “were -placed,” the late Professor Nichol wrote, “at intervals of -something upwards of a thousand yards, three groups of -musicians, who remained motionless during the requisite -period. Another musician on the railway sounded at intervals -one uniform note; and its effects on the ears of the -stationary musicians have been fully published. From these, -certainly—from the recorded changes between grave and the -more acute, and <i xml:lang="la" lang="la">vice versâ</i>,—confirming, even <em>numerically</em>, -what the relative velocities might have enabled one to predict, -it appears justifiable to conclude that the general theory -is correct; and that the note of any sound may be greatly -modified, if not wholly changed, by the velocity of the individual -hearing it,” or, he should have added, by the velocity -of the source of sound: perhaps more correct than either, is -the statement that the note may be altered by the approach -or recession of the source of sound, whether that be caused -by the motion of the sounding body, or of the hearer himself, -or of both.</p> - -<p>It is difficult, indeed, to understand how doubt can exist -in the mind of any one competent to form an opinion on -the matter, though, as we shall presently see, some students -of science and one or two mathematicians have raised doubts -as to the validity of the reasoning by which it is shown that -a change should occur. That the reasoning is sound cannot, -in reality, be questioned, and after careful examination of -the arguments urged against it by one or two mathematicians,<span class="pagenum"><a id="Page_85">85</a></span> -I can form no other opinion than that these arguments -amount really but to an expression of inability to understand -the matter. This may seem astonishing, but is explained -when we remember that some mathematicians, by devoting -their attention too particularly to special departments, lose, -to a surprising degree, the power of dealing with subjects -(even mathematical ones) outside their department. Apart -from the soundness of the reasoning, the facts are unmistakably -in accordance with the conclusion to which the -reasoning points. Yet some few still entertain doubts, a -circumstance which may prove a source of consolation to -any who find themselves unable to follow the reasoning on -which the effects of approach and recession on wave-lengths -depend. Let such remember, however, that experiment in -the case of the aerial waves producing sound, accords perfectly -with theory, and that the waves which produce light -are perfectly analogous (so far as this particular point is concerned) -with the waves producing sound.</p> - -<p>Ordinary white light, and many kinds of coloured light, -may be compared with <em>noise</em>—that is, with a multitude of -intermixed sounds. But light of one pure colour may be -compared to sound of one determinate note. As the aerial -waves producing the effect of one definite tone are all of one -length, so the ethereal waves producing light of one definite -colour are all of one length. Therefore if we approach or -recede from a source of light emitting such waves, effects -will result corresponding with what has been described above -for the case of water-waves and sound-waves. If we approach -the source of light, or if it approaches us, the waves -will be shortened; if we recede from it, or if it recedes from -us, the waves will be lengthened. But the colour of light -depends on its wave-length, precisely as the tone of sound -depends on its wave-length. The waves producing red -light are longer than those producing orange light, these are -longer than the waves producing yellow light; and so the -wave-lengths shorten down from yellow to green, thence to -blue, to indigo, and finally to violet. Thus if a body shining<span class="pagenum"><a id="Page_86">86</a></span> -in reality with a pure green colour, approached the observer -with a velocity comparable with that of light, it would seem -blue, indigo, or violet, according to the rate of approach; -whereas if it rapidly receded, it would seem yellow, orange, -or red, according to the rate of recession.</p> - -<p>Unfortunately in one sense, though very fortunately in -many much more important respects, the rates of motion -among the celestial bodies are <em>not</em> comparable with the -velocity of light, but are always so much less as to be almost -rest by comparison. The velocity of light is about 187,000 -miles per second, or, according to the measures of the solar -system at present in vogue (which will shortly have to give -place to somewhat larger measures, the result of observations -made upon the recent transit of Venus), about 185,000 -miles per second. The swiftest celestial motion of which we -have ever had direct evidence was that of the comet of the -year 1843, which, at the time of its nearest approach to the -sun, was travelling at the rate of about 350 miles per second. -This, compared with the velocity of light, is as the motion -of a person taking six steps a minute, each less than half a -yard long, to the rush of the swiftest express train. No -body within our solar system can travel faster than this, the -motion of a body falling upon the sun from an infinite distance -being only about 370 miles per second when it reaches -his surface. And though swifter motions probably exist -among the bodies travelling around more massive suns than -ours, yet of such motions we can never become cognizant. -All the motions taking place among the stars themselves -would appear to be very much less in amount. The most -swiftly moving sun seems to travel but at the rate of about -50 or 60 miles per second.</p> - -<p>Now let us consider how far a motion of 100 miles per -second might be expected to modify the colour of pure -green light—selecting green as the middle colour of the -spectrum. The waves producing green light are of such a -length, that 47,000 of them scarcely equal in length a single -inch. Draw on paper an inch and divide it carefully into<span class="pagenum"><a id="Page_87">87</a></span> -ten equal parts, or take such parts from a well-divided rule; -divide one of these tenths into ten equal parts, as nearly as -the eye will permit you to judge; then one of these parts, or -about half the thickness of an average pin, would contain -475 of the waves of pure green light. The same length -would equal the length of 440 waves of pure yellow light, -and of 511 waves of pure blue light. (The green, yellow, -and blue, here spoken of, are understood to be of the -precise colour of the middle of the green, yellow, and blue -parts of the spectrum.) Thus the green waves must be -increased in the proportion of 475 to 440 to give yellow -light, or reduced in the proportion of 511 to 475 to give -blue light. For the first purpose, the velocity of recession -must bear to the velocity of light the proportion which 30 -bears to 475, or must be equal to rather more than one-sixteenth -part of the velocity of light—say 11,600 miles per -second. For the second purpose, the velocity of approach -must bear to the velocity of light the proportion which -36 bears to 475, or must be nearly equal to one-thirteenth -part of the velocity of light—say 14,300 miles per second. -But the motions of the stars and other celestial bodies, and -also the motions of matter in the sun, and so forth, are very -much less than these. Except in the case of one or two -comets (and always dismissing from consideration the -amazing apparent velocities with which comets’ tails <em>seem</em> to -be formed), we may take 100 miles per second as the -extreme limit of velocity with which we have to deal, in -considering the application of our theory to the motions of -recession and approach of celestial bodies. Thus in the -case of recession the greatest possible change of colour in -pure green light would be equivalent to the difference -between the medium green of the spectrum, and the colour -1-116th part of the way from medium green to medium -yellow; and in the case of approach, the change would correspond -to the difference between the medium green and -the colour 1-143rd part of the way from medium green to -medium blue. Let any one look at a spectrum of fair<span class="pagenum"><a id="Page_88">88</a></span> -length, or even at a correctly tinted painting of the solar -spectrum, and note how utterly unrecognizable to ordinary -vision is the difference of tint for even the twentieth part of -the distance between medium green and medium yellow on -one side or medium blue on the other, and he will recognize -how utterly hopeless it would be to attempt to appreciate -the change of colour due to the approach or recession -of a luminous body shining with pure green light and -moving at the tremendous rate of 100 miles per second. -It would be hopeless, even though we had the medium green -colour and the changed colour, either towards yellow or -towards blue, placed side by side for comparison—how -much more when the changed colour would have to be -compared with the observer’s recollection of the medium -colour, as seen on some other occasion!</p> - -<p>But this is the least important of the difficulties affecting -the application of this method by noting change of colour, -as Doppler originally proposed. Another difficulty, which -seems somehow to have wholly escaped Doppler’s attention, -renders the colour test altogether unavailable. We do not -get <em>pure</em> light from any of the celestial bodies except certain -gaseous clouds or nebulæ. From every sun we get, as from -our own sun, all the colours of the rainbow. There may be -an excess of some colours and a deficiency of others in any -star, so as to give the star a tint, or even a very decided -colour. But even a blood-red star, or a deep-blue or violet -star, does not shine with pure light, for the spectroscope -shows that the star has other colours than those producing -the prevailing tint, and it is only the great <em>excess</em> of red -rays (all kinds of red, too) or of blue rays (of all kinds), and -so on, which makes the star appear red, or blue, and so on, -to the eye. By far the greater number of stars or suns -show all the colours of the rainbow nearly equally distributed, -as in the case of our own sun. Now imagine for a -moment a white sun, which had been at rest, to begin suddenly -to approach us so rapidly (travelling more than 10,000 -miles per second) that the red rays became orange, the<span class="pagenum"><a id="Page_89">89</a></span> -orange became yellow, the yellow green, the green blue, -the blue indigo, the indigo violet, while the violet waves -became too short to affect the sense of sight. Then, <em>if that -were all</em>, that sun, being deprived of the red part of its -light, would shine with a slightly bluish tinge, owing to the -relative superabundance of rays from the violet end of the -spectrum. We should be able to recognize such a change, -yet not nearly so distinctly as if that sun had been shining -with a pure green light, and suddenly beginning to approach -us at the enormous rate just mentioned, changed in colour -to full blue. <em>Though</em>, if that sun were all the time approaching -us at the enormous rate imagined, we should be quite -unable to tell whether its slightly bluish tinge were due to -such motion of approach or to some inherent blueness in -the light emitted by the star. Similarly, if a white sun -suddenly began to recede so rapidly that its violet rays were -turned to indigo, the indigo to blue, and so on, the orange -rays turning to red, and the red rays disappearing altogether, -then, <em>if that were all</em>, its light would become slightly reddish, -owing to the relative superabundance of light from the -red end of the spectrum; and we might distinguish the -change, yet not so readily as if a sun shining with pure green -light began to recede at the same enormous rate, and so -shone with pure yellow light. <em>Though</em>, if that sun were all -the time receding at that enormous rate, we should be quite -unable to tell whether its slightly reddish hue were due to -such motion of recession or to some inherent redness in its -own lustre. <em>But in neither case would that be all.</em> In the -former, the red rays would indeed become orange; but the -rays beyond the red, which produce no effect upon vision, -would be converted into red rays, and fill up the part of the -spectrum deserted by the rays originally red. In the latter, -the violet rays would indeed become indigo; but the rays -beyond the violet, ordinarily producing no visible effect, -would be converted into violet rays, and fill up the part of -the spectrum deserted by the rays originally violet. Thus, -despite the enormous velocity of approach in one case and<span class="pagenum"><a id="Page_90">90</a></span> -of recession in the other, there would be no change whatever -in the colour of the sun in either case. All the colours of -the rainbow would still be present in the sun’s light, and it -would therefore still be a white sun.</p> - -<p>Doppler’s method would thus fail utterly, even though -the stars were travelling hither and thither with motions -a hundred times greater than the greatest known stellar -motions.</p> - -<p>This objection to Doppler’s theory, as originally proposed, -was considered by me in an article on “Coloured Suns” in -<cite>Fraser’s Magazine</cite> for January, 1868. His theory, indeed, -was originally promulgated not as affording a means of -measuring stellar motions, but as a way of accounting for -the colours of double stars. It was thus presented by -Professor Nichol, in a chapter of his “Architecture of the -Heavens,” on this special subject:—“The rapid motion of -light reaches indeed one of those numbers which reason -owns, while imagination ceases to comprehend them; but it -is also true that the swiftness with which certain individuals -of the double stars sweep past their perihelias, or rather -their periasters, is amazing; and in this matter of colours, it -must be recollected that the question solely regards the -difference between the velocities of the waves constituent of -colours, at those different stellar positions. Still it is a bold—even -a magnificent idea; and if it can be reconciled with -the permanent colours of the multitude of stars surrounding -us—stars which too are moving in great orbits with immense -velocities—it may be hailed almost as a positive discovery. -It must obtain confirmation, or otherwise, so soon as we can -compare with certainty the observed colorific changes of -separate systems with the known fluctuations of their orbital -motions.”</p> - -<p>That was written a quarter of a century ago, when spectroscopic -analysis, as we now know it, had no existence. -Accordingly, while the fatal objection to Doppler’s original -theory is overlooked on the one hand, the means of applying -the principle underlying the theory, in a much more exact<span class="pagenum"><a id="Page_91">91</a></span> -manner than Doppler could have hoped for, is overlooked -on the other. Both points are noted in the article above -referred to, in the same paragraph. “We may dismiss,” I -there stated, “the theory started some years ago by the -French astronomer, M. Doppler.” But, I presently added, -“It is quite clear that the effects of a motion rapid enough -to produce such a change” (<i>i.e.</i> a change of tint in a pure -colour) “would shift the position of the whole spectrum—and -this change would be readily detected by a reference to -the spectral lines.” This is true, even to the word “readily.” -Velocities which would produce an appreciable change of -tint would produce “readily” detectible changes in the position -of the spectral lines; the velocities actually existing -among the star-motions would produce changes in the position -of these lines detectible only with extreme difficulty, or -perhaps in the majority of instances not detectible at all.</p> - -<p>It has been in this way that the spectroscopic method -has actually been applied.</p> - -<p>It is easy to perceive the essential difference between this -way of applying the method and that depending on the -attempted recognition of changes of colour. A dark line in -the spectrum marks in reality the place of a missing tint. -The tints next to it on either side are present, but the tint -between them is wanting. They are changed in colour—very -slightly, in fact quite inappreciably—by motions of recession -or approach, or, in other words, they are shifted in -position along the spectrum, towards the red end for recession, -towards the violet end for approach; and of course the -dark space between is shifted along with them. One may -say that the missing tint is changed. For in reality that is -precisely what would happen. If the light of a star at rest -gave every tint of the spectrum, for instance, except mid-green -alone, and that star approached or receded so swiftly -that its motion would change pure green light to pure yellow -in one case, or pure blue in the other, then the effect on the -spectrum of such a star would be to throw the dark line -from the middle of the green part of the spectrum to the<span class="pagenum"><a id="Page_92">92</a></span> -middle of the yellow part in one case, or to the middle of -the blue part in the other. The dark line would be quite -notably shifted in either case. With the actual stellar -motions, though all the lines are more or less shifted, the -displacement is always exceedingly minute, and it becomes -a task of extreme difficulty to recognize, and still more to -measure, such displacement.</p> - -<p>When I first indicated publicly (January, 1868) the way -in which Doppler’s principle could alone be applied, two -physicists, Huggins in England and Secchi in Italy, were -actually endeavouring, with the excellent spectroscopes in -their possession, to apply this method. In March, 1868, -Secchi gave up the effort as useless, publicly announcing the -plan on which he had proceeded and his failure to obtain -any results except negative ones. A month later Huggins -also publicly announced the plan on which he had been -working, but was also able to state that in one case, that of -the bright star Sirius, he had succeeded in measuring a motion -in the line of sight, having discovered that Sirius was receding -from the earth at the rate of 41·4 miles per second. I say -was receding, because a part of the recession at the time of -observation was due to the earth’s orbital motion around the -sun. I had, at his request, supplied Huggins with the -formula for calculating the correction due to this cause, and, -applying it, he found that Sirius is receding from the sun at -the rate of about 29½ miles per second, or some 930 millions -of miles per annum.</p> - -<p>I am not here specially concerned to consider the actual -results of the application of this method since the time of -Huggins’s first success; but the next chapter of the history -of the method is one so interesting to myself personally that -I feel tempted briefly to refer to details. So soon as I had -heard of Huggins’s success with Sirius, and that an instrument -was being prepared for him wherewith he might hope to -extend the method to other stars, I ventured to make a -prediction as to the result which he would obtain whensoever -he should apply it to five stars of the seven forming the so-<span class="pagenum"><a id="Page_93">93</a></span>called -Plough. I had found reason to feel assured that these -five form a system drifting all together amid stellar space. -Satisfied for my own part as to the validity of the evidence, -I submitted it to Sir J. Herschel, who was struck by its force. -The apparent drift of those stars was, of course, a thwart -drift; but if they really were drifting in space, then their -motions in the line of sight must of necessity be alike. My -prediction, then, was that whensoever Huggins applied to -those stars the new method he would find them either all -receding at the same rate, or all approaching at the same rate, -or else that all <em>alike</em> failed to give any evidence at all either -of recession or approach. I had indicated the five in the -first edition of my “Other Worlds”—to wit, the stars of the -Plough, omitting the nearest “pointer” to the pole and the -star marking the third horse (or the tip of the Great Bear’s -tail). So soon as Huggins’s new telescope and its spectroscopic -adjuncts were in working order, he re-examined Sirius, -determined the motions of other stars; and at last on one -suitable evening he tested the stars of the Plough. He -began with the nearest pointer, and found that star swiftly -approaching the earth. He turned to the other pointer, and -found it rapidly receding from the earth. Being under the -impression that my five included both pointers, he concluded -that my prediction had utterly failed, and so went on with -his observations, altogether unprejudiced in its favour, to say -the least. The next star of the seven he found to be receding -at the same rate as the second pointer; the next at the -same rate, the next, and the next receding still at the same -rate, and lastly the seventh receding at a different rate. -Here, then, were five stars all receding at a common rate, -and of the other two one receding at a different rate, the -other swiftly approaching. Turning next to the work containing -my prediction, Huggins found that the five stars thus -receding at a common rate were the five whose community -of motion I had indicated two years before. Thus the first -prediction ever made respecting the motions of the so-called -fixed stars was not wanting in success. I would venture to<span class="pagenum"><a id="Page_94">94</a></span> -add that the theory of star-drift, on the strength of which -the prediction was made, was in effect demonstrated by the -result.</p> - -<p>The next application of the new method was one of -singular interest. I believe it was Mr. Lockyer who first -thought of applying the method to measure the rate of solar -hurricanes as well as the velocities of the uprush and downrush -of vaporous matter in the atmosphere of the sun. -Another spectroscopic method had enabled astronomers to -watch the rush of glowing matter from the edge of the sun, -by observing the coloured flames and their motions; but by -the new method it was possible to determine whether the -flames at the edge were swept by solar cyclones carrying -them from or towards the eye of the terrestrial observer, -and also to determine whether glowing vapours over the -middle of the visible disc were subject to motion of uprush, -which of course would carry them towards the eye, or of -downrush, which would carry them from the eye. The -result of observations directed to this end was to show -that at least during the time when the sun is most spotted, -solar hurricanes of tremendous violence take place, while -the uprushing and downrushing motions of solar matter -sometimes attain a velocity of more than 100 miles per -second.</p> - -<p>It was this success on the part of an English spectroscopist -which caused that attack on the new method against -which it has but recently been successfully defended, at -least in the eyes of those who are satisfied only by experimental -tests of the validity of a process. The Padre -Secchi had failed, as we have seen, to recognize motions -of recession and approach among the stars by the new -method. But he had taken solar observation by spectroscopic -methods under his special charge, and therefore -when the new results reached his ears he felt bound to -confirm or invalidate them. He believed that the apparent -displacement of dark lines in the solar spectrum might be -due to the heat of the sun causing changes in the delicate<span class="pagenum"><a id="Page_95">95</a></span> -adjustments of the instrument—a cause of error against -which precautions are certainly very necessary. He satisfied -himself that when sufficient precautions are taken no displacements -take place such as Lockyer, Young, and others -claimed to have seen. But he submitted the matter to a -further test. As the sun is spinning swiftly on his axis, -his mighty equator, more than two and a half millions of -miles in girth, circling once round in about twenty-four -days, it is clear that on one side the sun’s surface is swiftly -moving <em>towards</em>, and on the other side as swiftly moving -<em>from</em>, the observer. By some amazing miscalculation, Secchi -made the rate of this motion 20 miles per second, so that -the sum of the two motions in opposite directions would -equal 40 miles per second. He considered that he ought -to be able by the new method, if the new method is -trustworthy at all, to recognize this marked difference -between the state of the sun’s eastern and western edges; -he found on trial that he could not do so; and accordingly -he expressed his opinion that the new method is not trustworthy, -and that the arguments urged in its favour are -invalid.</p> - -<p>The weak point in his reasoning resided in the circumstance -that the solar equator is only moving at the -rate of about 1¼ miles per second, so that instead of a -difference of 40 miles per second between the two edges, -which should be appreciable, the actual difference (that is, -the sum of the two equal motions in opposite directions) -amounts only to 2½ miles per second, which certainly -Secchi could not hope to recognize with the spectroscopic -power at his disposal. Nevertheless, when the error in his -reasoning was pointed out, though he admitted that error, -he maintained the justice of his conclusion; just as Cassini, -having mistakenly reasoned that the degrees of latitude -should diminish towards the pole instead of increasing, and -having next mistakenly found, as he supposed, that they do -diminish, acknowledged the error of his reasoning, but -insisted on the validity of his observations,—maintaining<span class="pagenum"><a id="Page_96">96</a></span> -thenceforth, as all the world knows, that the earth is extended -instead of flattened at the poles.</p> - -<p>Huggins tried to recognize by the new method the -effects of the sun’s rotation, using a much more powerful -spectroscope than Secchi’s. The history of the particular -spectroscope he employed is in one respect specially interesting -to myself, as the extension of spectroscopic power -was of my own devising before I had ever used or even -seen a powerful spectroscope. The reader is aware that -spectroscopes derive their light-sifting power from the prisms -forming them. The number of prisms was gradually increased, -from Newton’s single prism to Fraunhofer’s pair, -and to Kirchhoff’s battery of four, till six were used, -which bent the light round as far as it would go. Then -the idea occurred of carrying the light to a higher level -(by reflections) and sending it back through the same -battery of prisms, doubling the dispersion. Such a battery, -if of six prisms, would spread the spectral colours twice -as widely apart as six used in the ordinary way, and would -thus have a dispersive power of twelve prisms. It occurred -to me that after taking the rays through six prisms, arranged -in a curve like the letter C, an intermediate four-cornered -prism of a particular shape (which I determined) might be -made to send the rays into another battery of six prisms, the -entire set forming a double curve like the letter S, the rays -being then carried to a higher level and back through the -double battery. In this way a dispersive power of nineteen -prisms could be secured. My friend, Mr. Browning, the -eminent optician, made a double battery of this kind,<a id="FNanchor_13" href="#Footnote_13" class="fnanchor">13</a><span class="pagenum"><a id="Page_97">97</a></span> -which was purchased by Mr. W. Spottiswoode, and by him -lent to Mr. Huggins for the express purpose of dealing with -the task Secchi had set spectroscopists. It did not, however, -afford the required evidence. Huggins considered the -displacement of dark lines due to the sun’s rotation to be -recognizable, but so barely that he could not speak confidently -on the point.</p> - -<p>There for a while the matter rested. Vögel made observations -confirming Huggins’s results relative to stellar -motions; but Vögel’s instrumental means were not sufficiently -powerful to render his results of much weight.</p> - -<p>But recently two well-directed attacks have been made -upon this problem, one in England, the other in America, -and in both cases with success. Rather, perhaps, seeing -that the method had been attacked and was supposed to -require defence, we may say that two well-directed assaults -have been made upon the attacking party, which has been -completely routed.</p> - -<p>Arrangements were made not very long ago, by which -the astronomical work of Greenwich Observatory, for a long -time directed almost exclusively to time observations, should -include the study of the sun, stars, planets, and so forth. -Amongst other work which was considered suited to the -National Observatory was the application of spectroscopic -analysis to determine motions of recession and approach -among the celestial bodies. Some of these observations, -by the way, were made, we are told, “to test the truth -of Doppler’s principle,” though it seems difficult to suppose -for an instant that mathematicians so skilful as the chief -of the Observatory and some of his assistants could entertain -any doubt on that point. Probably it was intended -by the words just quoted to imply simply that some of -the observations were made for the purpose of illustrating -the principle of the method. We are not to suppose that -on a point so simple the Greenwich observers have been in -any sort of doubt.</p> - -<p>At first their results were not very satisfactory. The<span class="pagenum"><a id="Page_98">98</a></span> -difficulties which had for a long time foiled Huggins, and -which Secchi was never able to master, rendered the first -Greenwich measures of stellar motions in the line of sight -wildly inconsistent, not only with Huggins’s results, but with -each other.</p> - -<p>Secchi was not slow to note this. He renewed his objections -to the new method of observation, pointing and illustrating -them by referring to the discrepancies among the -Greenwich results. But recently a fresh series of results has -been published, showing that the observers at Greenwich -have succeeded in mastering some at least among the difficulties -which they had before experienced. The measurements -of star-motions showed now a satisfactory agreement -with Huggins’s results, and their range of divergence among -themselves was greatly reduced. The chief interest of the -new results, however, lay in the observations made upon -bodies known to be in motion in the line of sight at rates -already measured. These observations, though not wanted -as tests of the accuracy of the principle, were very necessary -as tests of the qualities of the instruments used in applying -it. It is here and thus that Secchi’s objections alone required -to be met, and here and thus they have been -thoroughly disposed of. Let us consider what means exist -within the solar system for thus testing the new method.</p> - -<p>The earth travels along in her orbit at the rate of about -18⅓ miles in every second of time. Not to enter into niceties -which could only properly be dealt with mathematically, -it may be said that with this full velocity she is at times -approaching the remoter planets of the system, and at times -receding from them; so that here at once is a range of difference -amounting to about 37 miles per second, and fairly -within the power of the new method of observation. For -it matters nothing, so far as the new method is concerned, -whether the earth is approaching another orb by her motion, -or that orb approaching by its own motion. Again, the -plant Venus travels at the rate of about 21½ miles per -second, but as the earth travels only 3 miles a second less<span class="pagenum"><a id="Page_99">99</a></span> -swiftly, and the same way round, only a small portion of -Venus’s motion ever appears as a motion of approach towards -or recession from the earth. Still, Venus is sometimes -approaching and sometimes receding from the earth, -at a rate of more than 8 miles per second. Her light is -much brighter than that of Jupiter or Saturn, and accordingly -this smaller rate of motion would be probably more -easily recognized than the greater rate at which the giant -planets are sometimes approaching and at other times -receding from the earth. At least, the Greenwich observers -seem to have confined their attention to Venus, -so far as motions of planets in the line of sight are concerned. -The moon, as a body which keeps always at -nearly the same distance from us, would of course be the -last in the world to be selected to give positive evidence -in favour of the new method; but she serves to afford a -useful test of the qualities of the instruments employed. -If when these were applied to her they gave evidence of -motions of recession or approach at the rate of several miles -per second, when we know as a matter of fact that the -moon’s distance never<a id="FNanchor_14" href="#Footnote_14" class="fnanchor">14</a> varies by more than 30,000 miles -during the lunar month, her rate of approach or recession -thus averaging about one-fiftieth part of a mile per second, -discredit would be thrown on the new method—not, indeed, -as regards its principle, which no competent reasoner can -for a moment question, but as regards the possibility of -practically applying it with our present instrumental means.</p> - -<p>Observations have been made at Greenwich, both on -Venus and on the moon, by the new method, with results -entirely satisfactory. The method shows that Venus is -receding when she is known to be receding, and that she -is approaching when she is known to be approaching. Again, -the method shows no signs of approach or recession in the -moon’s case. It is thus in satisfactory agreement with the<span class="pagenum"><a id="Page_100">100</a></span> -known facts. Of course these results are open to the objection -that the observers have known beforehand what to -expect, and that expectation often deceives the mind, -especially in cases where the thing to be observed is not -at all easy to recognize. It will presently be seen that the -new method has been more satisfactorily tested, in this -respect, in other ways. It may be partly due to the effect -of expectation that in the case of Venus the motions of -approach and recession, tested by the new method, have -always been somewhat too great. A part of the excess -may be due to the use of the measure of the sun’s distance, -and therefore the measures of the dimensions of the solar -system, in vogue before the recent transit. These measures -fall short to some degree of those which result from the -observations made in December, 1874, on Venus in transit, -the sun’s distance being estimated at about 91,400,000 miles -instead of 92,000,000 miles, which would seem to be nearer -the real distance. Of course all the motions within the -solar system would be correspondingly under-estimated. On -the other hand, the new method would give all velocities -with absolute correctness if instrumental difficulties could -be overcome. The difference between the real velocities -of Venus approaching and receding, and those calculated -according to the present inexact estimate of the sun’s distance, -is however much less than the observed discrepancy, -doubtless due to the difficulties involved in the application -of this most difficult method. I note the point, chiefly for -the sake of mentioning the circumstance that theoretically -the method affords a new means of measuring the dimensions -of the solar system. Whensoever the practical application -of the method has been so far improved that the -rate of approach or recession of Venus, or Mercury, or -Jupiter, or Saturn (any one of these planets), can be -determined on any occasion, with great nicety, we can at -once infer the sun’s distance with corresponding exactness. -Considering that the method has only been invented -ten years (setting aside Doppler’s first vague ideas respecting -it), and that spectroscopic analysis as a method of exact<span class="pagenum"><a id="Page_101">101</a></span> -observation is as yet little more than a quarter of a century -old, we may fairly hope that in the years to come the new -method, already successfully applied to measure motions of -recession and approach at the rate of 20 or 30 miles per -second, will be employed successfully in measuring much -smaller velocities. Then will it give us a new method of -measuring the great base-line of astronomical surveying—the -distance of our world from the centre of the solar -system.</p> - -<p>That this will one day happen is rendered highly probable, -in my opinion, by the successes next to be related.</p> - -<p>Besides the motions of the planets around the sun, there -are their motions of rotation, and the rotation of the sun -himself upon his axis. Some among these turning motions -are sufficiently rapid to be dealt with by the new method. -The most rapid rotational motion with which we are -acquainted from actual observation is that of the planet -Jupiter. The circuit of his equator amounts to about -267,000 miles, and he turns once on his axis in a few minutes -less than ten hours, so that his equatorial surface travels at -the rate of about 26,700 miles an hour, or nearly 7½ miles -per second. Thus between the advancing and retreating -sides of the equator there is a difference of motion in the -line of sight amounting to nearly 15 miles. But this is not -all. Jupiter shines by reflecting sunlight. Now it is easily -seen that where his turning equator <em>meets</em> the waves of light -from the sun, these are shortened, in the same sense that -waves are shortened for a swimmer travelling to meet them, -while these waves, already shortened in this way, are further -shortened when starting from the same advancing surface -of Jupiter, on their journey to us after reflection. In this -way the shortening of the waves is doubled, at least when -the earth is so placed that Jupiter lies in the same direction -from us as from the sun, the very time, in fact, when Jupiter -is most favourably placed for ordinary observation, or is at his -highest due south, when the sun is at his lowest below the -northern horizon—that is, at midnight. The lengthening<span class="pagenum"><a id="Page_102">102</a></span> -of the waves is similarly doubled at this most favourable -time for observation; and the actual difference between the -motion of the two sides of Jupiter’s equator being nearly -15 miles per second, the effect on the light-waves is -equivalent to that due to a difference of nearly 30 miles -per second. Thus the new method may fairly be expected -to indicate Jupiter’s motion of rotation. The Greenwich -observers have succeeded in applying it, though Jupiter has -not been favourably situated for observation. Only on one -occasion, says Sir G. Airy, was the spectrum of Jupiter -“seen fairly well,” and on that occasion “measures were -obtained which gave a result in remarkable agreement with -the calculated value.” It may well be hoped that when in -the course of a few years Jupiter returns to that part of his -course where he rises high above the horizon, shining more -brightly and through a less perturbed air, the new method -will be still more successfully applied. We may even hope -to see it extended to Saturn, not merely to confirm the -measures already made of Saturn’s rotation, but to resolve -the doubts which exist as to the rotation of Saturn’s ring-system.</p> - -<p>Lastly, there remains the rotation of the sun, a movement -much more difficult to detect by the new method, -because the actual rate of motion even at the sun’s equator -amounts only to about 1 mile per second.</p> - -<p>In dealing with this very difficult task, the hardest which -spectroscopists have yet attempted, the Greenwich observers -have achieved an undoubted success; but unfortunately for -them, though fortunately for science, another observatory, -far smaller and of much less celebrity, has at the critical -moment achieved success still more complete.</p> - -<p>The astronomers at our National Observatory have been -able to recognize by the new method the turning motion of -the sun upon his axis. And here we have not, as in the -case of Venus, to record merely that the observers have -seen what they expected to see because of the known -motion of the sun. “Particular care was taken,” says<span class="pagenum"><a id="Page_103">103</a></span> -Airy, “to avoid any bias from previous knowledge of the -direction in which a displacement” (of the spectral lines) -“was to be expected,” the side of the sun under observation -not being known by the observer until after the -observation was completed.</p> - -<p>But Professor Young, at Dartmouth College, Hanover, -N.H., has done much more than merely obtain evidence by -the new method that the sun is rotating as we already knew. -He has succeeded so perfectly in mastering the instrumental -and observational difficulties, as absolutely to be -able to rely on his <em>measurement</em> (as distinguished from the -mere recognition) of the sun’s motion of rotation. The -manner in which he has extended the powers of ordinary -spectroscopic analysis, cannot very readily be described in -these pages, simply because the principles on which the -extension depends require for their complete description -a reference to mathematical considerations of some complexity. -Let it be simply noted that what is called the -diffraction spectrum, obtained by using a finely lined plate, -results from the dispersive action of such a plate, or <em>grating</em> -as it is technically called, and this dispersive power can be -readily combined with that of a spectroscope of the ordinary -kind. Now Dr. Rutherfurd, of New York, has succeeded -in ruling so many thousand lines on glass within the breadth -of a single inch as to produce a grating of high dispersive -power. Availing himself of this beautiful extension of -spectroscopic powers, Professor Young has succeeded in -recognizing effects of much smaller motions of recession -and approach than had before been observable by the -new method. He has thus been able to measure the -rotation-rate of the sun’s equatorial regions. His result -exceeds considerably that inferred from the telescopic observation -of the solar spots. For whereas from the motion of -the spots a rotation-rate of about 1¼ mile per second has -been calculated for the sun’s equator, Professor Young -obtains from his spectroscopic observations a rate of rather -more than 1⅖ mile, or about 300 yards per second more -than the telescopic rate.</p> - -<p><span class="pagenum"><a id="Page_104">104</a></span> -If Young had been measuring the motion of the same -matter which is observed with the telescope, there could of -course be no doubt that the telescope was right and the -spectroscope wrong. We might add a few yards per second -for the probably greater distance of the sun resulting from -recent transit observations. For of course with an increase -in our estimate of the sun’s distance there comes an increase -in our estimate of the sun’s dimensions, and of the velocity -of the rotational motion of his surface. But only about -12 yards per second could be allowed on this account; -the rest would have to be regarded as an error due to the -difficulties involved in the spectroscopic method. In reality, -however, the telescopist and the spectroscopist observe -different things in determining by their respective methods -the sun’s motion of rotation. The former observes the -motion of the spots belonging to the sun’s visible surface; -the latter observes the motion of the glowing vapours outside -that surface, for it is from these vapours, not from the -surface of the sun, that the dark lines of the spectrum -proceed. Now so confident is Professor Young of the -accuracy of his spectroscopic observations, that he is -prepared to regard the seeming difference of velocity -between the atmosphere and surface of the sun as real. -He believes that “the solar atmosphere really sweeps -forward over the underlying surface, in the same way that -the equatorial regions outstrip the other parts of the sun’s -surface.” This inference, important and interesting in itself, -is far more important in what it involves. For if we can -accept it, it follows that the spectroscopic method of -measuring the velocity of motions in the line of sight -is competent, under favourable conditions, to obtain results -accurate within a few hundred yards per second, or 10 or -12 miles per minute. If this shall really prove to be -true for the method now, less than ten years after it -was first successfully applied, what may we not hope from -the method in future years? Spectroscopic analysis itself -is in its infancy, and this method is but a recent application<span class="pagenum"><a id="Page_105">105</a></span> -of spectroscopy. A century or so hence astronomers will -smile (though not disdainfully) at these feeble efforts, much -as we smile now in contemplating the puny telescopes -with which Galileo and his contemporaries studied the -star-depths. And we may well believe that largely as the -knowledge gained by telescopists in our own time surpasses -that which Galileo obtained, so will spectroscopists a few -generations hence have gained a far wider and deeper -insight into the constitution and movements of the stellar -universe than the spectroscopists of our own day dare even -hope to attain.</p> - -<p>I venture confidently to predict that, in that day, astronomers -will recognize in the universe of stars a variety -of structure, a complexity of arrangement, an abundance -of every form of cosmical vitality, such as I have been led -by other considerations to suggest, not the mere cloven -lamina of uniformly scattered stars more or less resembling -our sun, and all in nearly the same stage of cosmical development, -which the books of astronomy not many years -since agreed in describing. The history of astronomical progress -does not render it probable that the reasoning already -advanced, though in reality demonstrative, will convince the -generality of science students until direct and easily understood -observations have shown the real nature of the constitution -of that part of the universe over which astronomical -survey extends. But the evidence already obtained, though -its thorough analysis may be “<i xml:lang="fr" lang="fr">caviare</i> to the general,” suffices -to show the real nature of the relations which one day will -come within the direct scope of astronomical observation.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_106">106</a></span></p> - -<div class="chapter"> -<h2><a id="THE_NEW_STAR_WHICH_FADED_INTO_STAR-MIST"></a><i>THE NEW STAR WHICH FADED INTO STAR-MIST.</i></h2> -</div> - -<p class="in0">The appearance of a new star in the constellation of the -Swan in the autumn of 1876 promises to throw even more -light than was expected on some of the most interesting -problems with which modern astronomy has to deal. It -was justly regarded as a circumstance of extreme interest -that so soon after the outburst of the star which formed -a new gem in the Northern Crown in May, 1866, another -should have shone forth under seemingly similar conditions. -And when, as time went on, it appeared that in several -respects the new star in the Swan differed from the new star -in the Crown, astronomers found fresh interest in studying, -as closely as possible, the changes presented by the former -as it gradually faded from view. But they were not prepared -to expect what has actually taken place, or to recognize so -great a difference of character between these two new stars, -that whereas one seemed throughout its visibility to ordinary -eyesight, and even until the present time, to be justly called -a star, the other should so change as to render it extremely -doubtful whether at any time it deserved to be regarded as a -star or sun.</p> - -<p>Few astronomical phenomena, even of those observed -during this century (so fruitful in great astronomical discoveries), -seem better worthy of thorough investigation and -study than those presented by the two stars which appeared -in the Crown and in the Swan, in 1866 and 1876 respectively.<span class="pagenum"><a id="Page_107">107</a></span> -A new era seems indeed to be beginning for those -departments of astronomy which deal with stars and star-cloudlets -on the one hand, and with the evolution of solar -systems and stellar systems on the other.</p> - -<p>Let us briefly consider the history of the star of 1866 in -the first place, and then turn our thoughts to the more -surprising and probably more instructive history of the star -which shone out in November, 1876.</p> - -<p>In the first place, however, I would desire to make a few -remarks on the objections which have been expressed by an -observer to whom astronomy is indebted for very useful -work, against the endeavour to interpret the facts ascertained -respecting these so-called new stars. M. Cornu, who made -some among the earliest spectroscopic observations of the -star in Cygnus, after describing his results, proceeded as -follows:—“Grand and seductive though the task may be -of endeavouring to draw from observed facts inductions -respecting the physical state of this new star, respecting its -temperature, and the chemical reactions of which it may be -the scene, I shall abstain from all commentary and all hypothesis -on this subject. I think that we do not yet possess -the data necessary for arriving at useful conclusions, or at -least at conclusions capable of being tested: however -attractive hypotheses may be, we must not forget that -they are outside the bounds of science, and that, far from -serving science, they seriously endanger its progress.” This, -as I ventured to point out at the time, is utterly inconsistent -with all experience. M. Cornu’s objection to theorizing -when he did not see his way to theorizing justly, is sound -enough; but his general objection to theorizing is, with all -deference be it said, sheerly absurd. It will be noticed that -I say theorizing, not hypothesis-framing; for though he -speaks of hypotheses, he in reality is describing theories. -The word hypothesis is too frequently used in this incorrect -sense—perhaps so frequently that we may almost prefer -sanctioning the use to substituting the correct word. But -the fact really is, that many, even among scientific writers,<span class="pagenum"><a id="Page_108">108</a></span> -when they hear the word hypothesis, think immediately of -Newton’s famous “hypotheses non fingo,” a dictum relating -to real hypotheses, not to theories. It would, in fact, be -absurd to suppose that Newton, who had advanced, advocated, -and eventually established, the noblest scientific -theory the world has known, would ever have expressed an -objection to theorizing, as he is commonly understood to -have done by those who interpret his “hypotheses non -fingo” in the sense which finds favour with M. Cornu. But -apart from this, Newton definitely indicates what he means -by hypotheses. “I frame no hypotheses,” he says, “<em>for -whatever is not deduced from phenomena is to be called an -hypothesis</em>.” M. Cornu, it will be seen, rejects the idea of -deducing from phenomena what he calls an hypothesis, but -what would not be an hypothesis according to Newton’s -definition: “Malgré tout ce qu’il y aurait de séduisant et de -grandiose à tirer de ce fait des inductions, etc., je m’abstiendrai -de tout commentaire et de toute hypothèse à ce sujet.” -It is not thus that observed scientific facts are to be made -fruitful, nor thus that the points to which closer attention -must be given are to be ascertained.</p> - -<p>Since the preceding paragraph was written, my attention -has been attracted to the words of another observer more -experienced than M. Cornu, who has not only expressed the -same opinion which I entertain respecting M. Cornu’s ill-advised -remark, but has illustrated in a very practical way, -and in this very case, how science gains from commentary -and theory upon observed facts. Herr Vögel considers “that -the fear that an hypothesis” (he, also, means a theory here) -“might do harm to science is only justifiable in very rare -cases: in most cases it will further science. In the first -place, it draws the attention of the observer to things -which but for the hypothesis might have been neglected. -Of course if the observer is so strongly influenced that in -favour of an hypothesis he sees things which do not exist—and -this may happen sometimes—science may for a while -be arrested in its progress, but in that case the observer is<span class="pagenum"><a id="Page_109">109</a></span> -far more to blame than the author of the hypothesis. On -the other hand, it is very possible that an observer may, -involuntarily, arrest the progress of science, even without -originating an hypothesis, by pronouncing and publishing -sentences which have a tendency to diminish the general -interest in a question, and which do not place its high significance -in the proper light.” (This is very neatly put.) He -is “almost inclined to think that such an effect might follow -from the reading of M. Cornu’s remark, and that nowhere -better than in the present case, where in short periods -colossal changes showed themselves occurring upon a -heavenly body, might the necessary data be obtained for -drawing useful conclusions, and tests be applied to those -hypotheses which have been ventured with regard to the -condition of heavenly bodies.” It was, as we shall presently -see, in thus collecting data and applying tests, that Vögel -practically illustrated the justice of his views.</p> - -<p>The star which shone out in the Northern Crown in -May, 1866, would seem to have grown to its full brightness -very quickly. It is not necessary that I should here consider -the history of the star’s discovery; but I think all who -have examined that history agree in considering that whereas -on the evening of May 12, 1866, a new star was shining in -the Northern Crown with second-magnitude brightness, none -had been visible in the same spot with brightness above -that of a fifth-magnitude star twenty-four hours earlier. On -ascertaining, however, the place of the new star, astronomers -found that there had been recorded in Argelander’s -charts and catalogue a star of between the ninth and tenth -magnitude in this spot. The star declined very rapidly in -brightness. On May 13th it appeared of the third magnitude; -on May 16th it had sunk to the fourth magnitude; -on the 17th to the fifth; on the 19th to the seventh; and -by the end of the month it shone only as a telescopic star -of the ninth magnitude. It is now certainly not above the -tenth magnitude.</p> - -<p>Examined with the spectroscope, this star was found to<span class="pagenum"><a id="Page_110">110</a></span> -be in an abnormal condition. It gave the rainbow-tinted -streak crossed by dark lines, which is usually given by stars -(with minor variations, which enable astronomers to classify -the stars into several distinct orders). But superposed upon -this spectrum, or perhaps we should rather say shining -through this spectrum, were seen four brilliant lines, two -of which certainly belonged to glowing hydrogen. These -lines were so bright as to show that the greater part of the -light of the star at the time came from the glowing gas or -gases giving these lines. It appeared, however, that the -rainbow-tinted spectrum on which these lines were seen was -considerably brighter than it would otherwise have been, in -consequence of the accession of heat indicated by and -probably derived from the glowing hydrogen.</p> - -<p>Unfortunately, we have not accordant accounts of the -changes which the spectrum of this star underwent as the -star faded out of view. Wolf and Rayet, of the Paris -Observatory, assert that when there remained scarcely any -trace of the continuous spectrum, the four bright lines were -still quite brilliant. But Huggins affirms that this was not -the case in his observations; he was “able to see the continuous -spectrum when the bright lines could be scarcely -distinguished.” As the bright lines certainly faded out of -view eventually, we may reasonably assume that the French -observers were prevented by the brightness of the lines from -recognizing the continuous spectrum at that particular stage -of the diminution of the star’s light when the continuous -spectrum had faded considerably but the hydrogen lines -little. Later, the continuous spectrum ceased to diminish in -brightness, while the hydrogen lines rapidly faded. Thereafter -the continuous spectrum could be discerned, and with greater -and greater distinctness as the hydrogen lines faded out.</p> - -<p>Now, in considering the meaning of the observed changes -in the so-called “new star,” we have two general theories to -consider.</p> - -<p>One of these theories is that to which Dr. Huggins -would seem to have inclined, though he did not definitely<span class="pagenum"><a id="Page_111">111</a></span> -adopt it—the theory, namely, that in consequence of some -internal convulsion enormous quantities of hydrogen and -other gases were evolved, which in combining with some -other elements ignited on the surface of the star, and thus -enveloped the whole body suddenly in a sheet of flame.</p> - -<p>“The ignited hydrogen gas in burning produced the -light corresponding to the two bright bands in the red and -green; the remaining bright lines were not, however, coincident -with those of oxygen, as might have been expected. -According to this theory, the burning hydrogen must have -greatly increased the heat of the solid matter of the photosphere -and brought it into a state of more intense incandescence -and luminosity, which may explain how the formerly -faint star could so suddenly assume such remarkable brilliance; -the liberated hydrogen became exhausted, the -flame gradually abated, and with the consequent cooling the -photosphere became less vivid, and the star returned to its -original condition.”</p> - -<p>According to the other theory, advanced by Meyer and -Klein, the blazing forth of this new star may have been -occasioned by the violent precipitation of some great mass, -perhaps a planet, upon a fixed star, “by which the -momentum of the falling mass would be changed into -molecular motion,” and result in the emission of light and -heat.</p> - -<p>“It might even be supposed that the new star, through -its rapid motion, may have come in contact with one of the -nebulæ which traverse in great numbers the realms of space -in every direction, and which from their gaseous condition -must possess a high temperature; such a collision would -necessarily set the star in a blaze, and occasion the most -vehement ignition of its hydrogen.”</p> - -<p>If we regard these two theories in their more general -aspect, considering one as the theory that the origin of disturbance -was within the star, and the other as the theory -that the origin of disturbance was outside the star, they -seem to include all possible interpretations of the observed<span class="pagenum"><a id="Page_112">112</a></span> -phenomena. But, as actually advanced, neither seems -satisfactory. The sudden pouring forth of hydrogen from -the interior, in quantities sufficient to explain the outburst, -seems altogether improbable. On the other hand, as I -have pointed out elsewhere, there are reasons for rejecting -the theory that the cause of the heat which suddenly affected -this star was either the downfall of a planet on the star or -the collision of the star with a star-cloudlet or nebula, -traversing space in one direction, while the star rushed -onwards in another.</p> - -<p>A planet could not very well come into final conflict -with its sun at one fell swoop. It would gradually draw -nearer and nearer, not by the narrowing of its path, but by -the change of the path’s shape. The path would, in fact, -become more and more eccentric; until at length, at its -point of nearest approach, the planet would graze its -primary, exciting an intense heat where it struck, but -escaping actual destruction that time. The planet would -make another circuit, and again graze the sun, at or near -the same part of the planet’s path. For several circuits this -would continue, the grazes not becoming more and more -effective each time, but rather less. The interval between -them, however, would grow continually less and less; at last -the time would come when the planet’s path would be -reduced to the circular form, its globe touching the sun’s -all the way round, and then the planet would very quickly -be reduced to vapour and partly burned up, its substance -being absorbed by its sun. But all successive grazes would -be indicated to us by accessions of lustre, the period between -each seeming outburst being only a few months at first, and -gradually becoming less and less (during a long course of -years, perhaps even of centuries) until the planet was -finally destroyed. Nothing of this sort has happened in the -case of any so-called new star. As for the rush of a star -through a nebulous mass, that is a theory which would -scarcely be entertained by any one acquainted with the -enormous distances separating the gaseous star-clouds<span class="pagenum"><a id="Page_113">113</a></span> -properly called nebulæ. There may be small clouds of -the same sort scattered much more freely through space; -but we have not a particle of evidence that this is actually -the case. All we certainly <em>know</em> about star-cloudlets suggests -that the distances separating them from each other are -comparable with those which separate star from star, in -which case the idea of a star coming into collision with a -star-cloudlet, and still more the idea of this occurring several -times in a century, is wild in the extreme.</p> - -<p>But while thus advancing objections, which seem to me -irrefragable, against the theory that either a planet or a -nebula (still less another small star) had come into collision -with the orb in Corona which shone out so splendidly for a -while, I advanced another view which seemed to me then -and seems now to correspond well with phenomena, and to -render the theory of action from without on the whole -preferable to the theory of outburst from within. I suggested -that, far more probably, an enormous flight of large -meteoric masses travelling around the star had come into -partial collision with it in the same way that the flight of -November meteors comes into collision with our earth -thrice in each century, and that other meteoric flights may -occasionally come into collision with our sun, producing the -disturbances which occasion the sun-spots. As I pointed -out, in conceiving this we are imagining nothing new. A -meteoric flight capable of producing the suggested effects -would differ only in kind from meteoric flights which are -known to circle around our own sun. The meteors which -produce the November displays of falling stars follow in the -track of a comet barely visible to the naked eye.</p> - -<p>“May we not reasonably assume that those glorious -comets which have not only been visible but conspicuous, -shining even in the day-time, and brandishing around tails, -which like that of the ‘wonder in heaven, the great dragon,’ -seemed to ‘draw the third part of the stars of heaven,’ are -followed by much denser flights of much more massive -meteors? Some of these giant comets have paths which<span class="pagenum"><a id="Page_114">114</a></span> -carry them very close to our sun. Newton’s comet, with its -tail a hundred millions of miles in length, all but grazed the -sun’s globe. The comet of 1843, whose tail, says Sir John -Herschel, ‘stretched half-way across the sky,’ must actually -have grazed the sun, though but lightly, for its nucleus was -within 80,000 miles of his surface, and its head was more -than 160,000 miles in diameter. And these are only two -among the few comets whose paths are known. At any -time we might be visited by a comet mightier than either, -travelling in an orbit intersecting the sun’s surface, followed -by flights of meteoric masses enormous in size and many in -number, which, falling on the sun’s globe with enormous -velocity corresponding to their vast orbital range and their -near approach to the sun—a velocity of some 360 miles per -second—would, beyond all doubt, excite his whole frame, -and especially his surface regions, to a degree of heat far -exceeding what he now emits.”</p> - -<p>This theory corresponds far better also with observed -facts than the theory of Meyer and Klein, in other respects -than simply in antecedent probability. It can easily be -shown that if a planet fell upon a sun in such sort as to -become part of his mass, or if a nebula in a state of intense -heat excited the whole frame of a star to a similar degree -of heat, the effects would be of longer duration than the -observed accession of heat and light in the case of all the -so-called “new stars.” It has been calculated by Mr. Croll -(the well-known mathematician to whom we owe the most -complete investigations yet made into the effect of the -varying eccentricity of the earth’s orbit on the climate of the -earth) that if two suns, each equal in mass to one-half of -our sun, came into collision with a velocity of 476 miles per -second, light and heat would be produced which would -cover the present rate of the sun’s radiation for fifty million -years. Now although it certainly does not follow from this -that such a collision would result in the steady emission of -so much light and heat as our sun gives out, for a period of -fifty million years, but is, on the contrary, certain that there<span class="pagenum"><a id="Page_115">115</a></span> -would be a far greater emission at first and a far smaller -emission afterwards, yet it manifestly must be admitted that -such a collision could not possibly produce so short-lived an -effect as we see in the case of every one of the so-called new -stars. The diminution in the emission of light and heat -from the maximum to one-half the maximum would not -occupy fifty millions of years, or perhaps even five million or -five hundred thousand years; but it would certainly require -thousands of years; whereas we have seen that the new stars -in the Crown and in the Swan have lost not one-half but -ninety-nine hundredths of their maximum lustre in a few -months.</p> - -<p>This has been urged as an objection even to the term -star as applied to these suddenly appearing orbs. But the -objection is not valid; because there is no reason whatever -for supposing that even our own sun might not be excited -by the downfall of meteoric or cometic matter upon it to -a sudden and short-lasting intensity of splendour and of -heat. Mr. Lockyer remarks that, if any star, properly so -called, were to become a “a world on fire,” or “burst into -flames,” or, in less poetical language, were to be driven -either into a condition of incandescence absolutely, or to -have its incandescence increased, there can be little doubt -that thousands or millions of years would be necessary for -the reduction of its light to its original intensity. This -must, however, have been written in forgetfulness of some -facts which have been ascertained respecting our sun, and -which indicate pretty clearly that the sun’s surface might be -roused to a temporary intensity of splendour and heat without -any corresponding increase in the internal heat, or in -the activity of the causes, whatever they may be, to which -the sun’s <em>steady</em> emissions of light and heat are due.</p> - -<p>For instance, most of my readers are doubtless familiar -with the account (an oft-told tale, at any rate) of the sudden -increase in the splendour of a small portion of the sun’s -surface on September 1, 1859, observed by two astronomers -independently. The appearances described corresponded<span class="pagenum"><a id="Page_116">116</a></span> -exactly with what we should expect if two large meteoric -masses travelling side by side had rushed, with a velocity -originally amounting to two or three hundred miles per -second, through the portions of the solar atmosphere lying -just above, at, and just below the visible photosphere. The -actual rate of motion was measured at 120 miles per second -as the minimum, but may, if the direction of motion was -considerably inclined to the line of sight, have amounted -to more than 200 miles per second. The effect was such, -that the parts of the sun thus suddenly excited to an -increased emission of light and heat appeared like bright -stars upon the background of the glowing photosphere -itself. One of the observers, Carrington, supposed for a -moment that the dark glass screen used to protect the eye -had broken. The increase of splendour was exceedingly -limited in area, and lasted only for a few minutes—fortunately -for the inhabitants of earth. As it was, the whole -frame of the earth sympathized with the sun. Vivid auroras -were seen, not only in both hemispheres, but in latitudes -where auroras are seldom seen. They were accompanied -by unusually great electro-magnetic disturbances.</p> - -<p>“In many places,” says Sir J. Herschel, “the telegraph -wires struck work. At 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, in North America, a flame of fire followed -the pen of Bain’s electric telegraph, which writes down the -message upon chemically prepared paper.”</p> - -<p>We see, then, that most certainly the sun can be locally -excited to increased emission of light and heat, which nevertheless -may last but for a very short time; and we have -good reason for believing that the actual cause of the sudden -change in his condition was the downfall of meteoric matter -upon a portion of his surface. We may well believe that, -whatever the cause may have been, it was one which might -in the case of other suns, or even in our sun’s own case, -affect a much larger portion of the photosphere. If this happened<span class="pagenum"><a id="Page_117">117</a></span> -there would be just such an accession of splendour as -we recognize in the case of the new stars. And as the small -local accession of brilliancy lasted only a few minutes, we can -well believe that an increase of surface brilliancy affecting a -much larger portion of the photosphere, or even the entire -photosphere, might last but for a few days or weeks.</p> - -<p>All that can be said in the way of negative evidence, so -far as our own sun is concerned, is that we have no reason -for believing that our sun has, at any time within many -thousands of years, been excited to emit even for a few hours -a much greater amount of light and heat than usual; so that -it has afforded no direct evidence in favour of the belief that -other suns may be roused to many times their normal splendour, -and yet very quickly resume that usual lustre. But we -know that our sun, whether because of his situation in space, -or of his position in time (that is, the stage of solar development -to which he has at present attained), belongs to the -class of stars which shine with steady lustre. He does not -vary like Betelgeux, for example, which is not only a sun like -him as to general character, but notably a larger and more -massive orb. Still less is he like Mira, the Wonderful Star; -or like that more wonderful variable star, Eta Argûs, which -at one time shines with a lustre nearly equalling that of the -bright Sirius, and anon fades away almost into utter invisibility. -He <em>is</em> a variable sun, for we cannot suppose that the -waxing and waning of the sun-spot period leaves his lustre, -as a whole, altogether unaffected. But his variation is so -slight that, with all ordinary methods of photometric measurement -by observers stationed on worlds which circle around -other suns, it must be absolutely undiscernible. We do not, -however, reject Betelgeux, or Mira, or even Eta Argûs, -from among stars because they vary in lustre. We recognize -the fact that, as in glory, so in condition and in changes of -condition, one star differeth from another.</p> - -<p>Doubtless there are excellent reasons for rejecting the -theory that a massive body like a planet, or a nebulous mass -like those which are found among the star-depths (the least<span class="pagenum"><a id="Page_118">118</a></span> -of which would exceed many times in volume a sphere filling -the entire space of the orbit of Neptune), fell on some remote -sun in the Northern Crown. But there are no sufficient -reasons for rejecting or even doubting the theory that a comet, -bearing in its train a flight of many millions of meteoric masses, -falling directly upon such a sun, might cause it to shine with -many times its ordinary lustre, but only for a short time, a few -months or weeks, or a few days, or even hours. In the article -entitled “Suns in Flames,” in my “Myths and Marvels of -Astronomy,” before the startling evidence recently obtained -from the star in Cygnus had been thought of, I thus indicated -the probable effects of such an event:—“When the earth has -passed through the richer portions (not the actual nuclei be it -remembered) of meteor systems, the meteors visible from even -a single station have been counted by tens of thousands, and -it has been computed that millions must have fallen upon -the whole earth. These were meteors following in the trains -of very small comets. If a very large comet followed by no -denser a flight of meteors, but each meteoric mass much -larger, fell directly upon the sun, it would not be the outskirts -but the nucleus of the meteoric train which would -impinge upon him. They would number thousands of -millions. The velocity of downfall of each mass would be -more than 360 miles per second. And they would continue -to pour in upon him for several days in succession, millions -falling every hour. It seems not improbable that under this -tremendous and long-continued meteoric hail, his whole surface -would be caused to glow as intensely as that small part -whose brilliancy was so surprising in the observation made -by Carrington and Hodgson. In that case our sun, seen -from some remote star whence ordinarily he is invisible, -would shine out as a new sun for a few days, while all things -living, on our earth and whatever other members of the solar -system are the abodes of life, would inevitably be destroyed.”</p> - -<p>There are, indeed, reasons for believing, not only, as I -have already indicated, that the outburst in the sun was -caused by the downfall of meteoric masses, but that those<span class="pagenum"><a id="Page_119">119</a></span> -masses were following in the train of a known comet, precisely -as the November meteors follow in the train of -Tempel’s comet (II., 1866). For we know that November -meteoric displays have been witnessed for five or six years -after the passage of Tempel’s comet, in its thirty-three year -orbit, while the August meteoric displays have been witnessed -fully one hundred and twenty years after the passage of their -comet (II., 1862).<a id="FNanchor_15" href="#Footnote_15" class="fnanchor">15</a> Now only sixteen years before the solar -outburst witnessed by Carrington and Hodgson, a magnificent -comet had passed even closer to the sun than either Tempel’s -comet or the second comet of 1862 approached the earth’s -orbit. That was the famous comet of the year 1843. Many -of us remember that wonderful object. I was but a child -myself when it appeared, but I can well remember its -amazing tail, which in March, 1843, stretched half-way across -the sky.</p> - -<p>“Of all the comets on record,” says Sir J. Herschel, -“that approached nearest the sun; indeed, it was at first -supposed that it had actually grazed the sun’s surface, but it -proved to have just missed by an interval of not more than -80,000 miles—about a third of the distance of the moon -from the earth, which (in such a matter) is a very close shave -indeed to get clear off.”</p> - -<p>We can well believe that the two meteors which produced -the remarkable outburst of 1859 may have been stragglers -from the main body following after that glorious comet. I -do not insist upon the connection. In fact, I rather incline -to the belief that the disturbance in 1859, occurring as it did -about the time of maximum sun-spot frequency, was caused -by meteors following in the train of some as yet undiscovered -comet, circuiting the sun in about eleven years, the spots<span class="pagenum"><a id="Page_120">120</a></span> -themselves being, I believe, due in the main to meteoric -downfalls. There is greater reason for believing that the -great sun-spot which appeared in June, 1843, was caused by -the comet which three months before had grazed the sun’s -surface. As Professor Kirkwood, of Bloomington, Indiana, -justly remarks, had this comet approached a little nearer, the -resistance of the solar atmosphere would probably have -brought the comet’s entire mass to the solar surface. Even -at its actual distance, it must have produced considerable -atmospheric disturbance. But the recent discovery that a -number of comets are associated with meteoric matter travelling -in nearly the same orbits, suggests the inquiry whether -an enormous meteorite following in the comet’s train, and -having a somewhat less perihelion distance, may not have been -precipitated upon the sun, thus producing the great disturbance -observed so shortly after the comet’s perihelion passage.</p> - -<p>Let us consider now the evidence obtained from the star -in Cygnus, noting especially in what points it resembles, and -in what points it differs from, the evidence afforded by the -star in the Crown.</p> - -<p>The new star was first seen by Professor Schmidt at a -quarter to six on the evening of November 24. It was then -shining as a star of the third magnitude, in the constellation -of the Swan, not very far from the famous but faint star 61 -Cygni—which first of all the stars in the northern heavens -had its distance determined by astronomers. The three -previous nights had unfortunately been dark; but Schmidt -is certain that on November 20 the star was not visible. At -midnight, November 24, its light was very yellow, and it was -somewhat brighter than the well-known star Eta Pegasi, -which marks the forearm of the Flying Horse. Schmidt -sent news of the discovery to Leverrier, at Paris; but neither -he nor Leverrier telegraphed the news, as they should have -done, to Greenwich, Berlin, or the United States. Many -precious opportunities for observing the spectrum of the -new-comer at the time of its greatest brilliancy were thus -lost.</p> - -<p><span class="pagenum"><a id="Page_121">121</a></span> -The observers at Paris did their best to observe the -spectrum of the star and the all-important changes in the -spectrum. But they had unfavourable weather. It was not -till December 2 that the star was observed at Paris, by which -time the colour, which had been very yellow on November -24, had become “greenish, almost blue.” The star had also -then sunk from the third to far below the fourth magnitude. -It is seldom that science has to regret a more important loss -of opportunity than this. What we want specially to know -is the nature of the spectrum given by this star when its -light was yellow; and this we can now never know. Nor -are the outbursts of new stars so common that we may -quickly expect another similar opportunity, even if any -number of other new stars should present the same series of -phenomena as the star in Cygnus.</p> - -<p>On December 2, the spectrum, as observed by M. -Cornu, consisted almost entirely of bright lines. On December -5, he determined the position of these lines, though -clouds still greatly interfered with his labours. He found -three bright lines of hydrogen, the strong double sodium -line in the orange-yellow, the triple magnesium line in the -yellow-green, and two other lines—one of which seemed to -agree exactly in position with a bright line belonging to the -solar corona. All these lines were shining upon the rainbow-tinted -background of the spectrum, which was relatively faint. -He drew the conclusion that in chemical constitution the -atmosphere of the new star was constituted exactly like the -solar sierra.</p> - -<p>Herr Vögel’s observations commenced on December 5, -and were continued at intervals until March 10, when the -star had sunk to below the eighth magnitude.</p> - -<p>Vögel’s earlier observations agreed well with Cornu’s. -He remarks, however, that Cornu’s opinion as to the exact -resemblance of the chemical constitution of the star’s atmosphere -with that of the sierra is not just, for both Cornu -and himself noticed one line which did not correspond -with any line belonging to the solar sierra; and this line<span class="pagenum"><a id="Page_122">122</a></span> -eventually became the brightest line of the whole spectrum. -Comparing his own observations with those of Cornu, -Vögel points out that they agree perfectly with regard to -the presence of the three hydrogen lines, and that of the -brightest line of the air spectrum (belonging to nitrogen),—which -is the principal line of the spectrum of nebulæ. -This is the line which has no analogue in the spectrum -of the sierra.</p> - -<p>We have also observations by F. Secchi, at Rome, Mr. -Copeland, at Dunecht, and Mr. Backhouse, of Sunderland, -all agreeing in the main with the observations made by -Vögel and Cornu. In particular, Mr. Backhouse observed, -as Vögel had done, that whereas in December the greenish-blue -line of hydrogen, F, was brighter than the nitrogen -line (also in the green-blue, but nearer the red end than -F), on January 6 the nitrogen line was the brightest of -all the lines in the spectrum of the new star.</p> - -<p>Vögel, commenting on the results of his observations up -to March 10, makes the following interesting remarks (I -quote, with slight verbal alterations, from a paraphrase in a -weekly scientific journal):—“A stellar spectrum with <em>bright</em> -lines is always a highly interesting phenomenon for any -one acquainted with stellar spectrum analysis, and well -worthy of deep consideration. Although in the chromosphere -(sierra) of our sun, near the limb, we see numerous -bright lines, yet only dark lines appear in the spectrum -whenever we produce a small star-like image of the sun, -and examine it through the spectroscope. It is generally -believed that the bright lines in some few star-spectra -result from gases which break forth from the interior of -the luminous body, the temperature of which is higher than -that of the surface of the body—that is, the phenomenon -is the same sometimes observed in the spectra of solar -spots, where incandescent hydrogen rushing out of the -hot interior becomes visible above the cooler spots through -the hydrogen lines turning bright. But this is not the only -possible explanation. We may also suppose that the atmosphere<span class="pagenum"><a id="Page_123">123</a></span> -of a star, consisting of incandescent gases, as is -the case with our own sun, is on the whole cooler than the -nucleus, but with regard to the latter is extremely large. -I cannot well imagine how the phenomenon can last for -any long period of time if the former hypothesis be correct. -The gas breaking forth from the hot interior of the body -will impart a portion of its heat to the surface of the body, -and thus raise the temperature of the latter; consequently, -the difference of temperature between the incandescent -gas and the surface of the body will soon be insufficient -to produce bright lines; and these will disappear from -the spectrum. This view applies perfectly to stars which -suddenly appear and soon disappear again, or at least -increase considerably in intensity—that is, it applies perfectly -to so-called new stars in the spectra of which bright -lines are apparent, <em>if</em> the hypothesis presently to be -mentioned is admitted for their explanation. For a more -stable state of things the second hypothesis seems to be -far better adapted. Stars like Beta Lyræ, Gamma Cassiopeiæ, -and others, which show the hydrogen lines and the -sierra D line bright on a continuous spectrum, with only -slight changes of intensity, possess, according to this theory, -atmospheres very large relatively to their own volume—the -atmospheres consisting of hydrogen and that unknown -element which produces the D line.<a id="FNanchor_16" href="#Footnote_16" class="fnanchor">16</a> With regard to the -new star, Zöllner, long before the progress lately made in -stellar physics by means of spectrum analysis, deduced from -Tycho’s observations of the star called after him, that on -the surface of a star, through the constant emission of heat, -the products of cooling, which in the case of our sun we call -sun-spots, accumulate: so that finally the whole surface of -the body is covered with a colder stratum, which gives<span class="pagenum"><a id="Page_124">124</a></span> -much less light or none at all. Through a sudden and -violent tearing up of this stratum, the interior incandescent -materials which it encloses must naturally break forth, and -must in consequence, according to the extent of their eruption, -cause larger or smaller patches of the dark envelope -of the body to become luminous again. To a distant observer -such an eruption from the hot and still incandescent -interior of a heavenly body must appear as the sudden -flashing-up of a new star. That this evolution of light -may under certain conditions be an extremely powerful -one, could be explained by the circumstance that all the -chemical compounds which, under the influence of a lower -temperature, had already formed upon the surface, are again -decomposed through the sudden eruption of these hot -materials; and that this decomposition, as in the case of -terrestrial substances, takes place under evolution of light -and heat. Thus the bright flashing-up is not only ascribed -to the parts of the surface which through the eruption of the -incandescent matter have again become luminous, but also -to a simultaneous process of combustion, which is initiated -through the colder compounds coming into contact with the -incandescent matter.”</p> - -<p>Vögel considers that Zöllner’s hypothesis has been confirmed -in its essential points by the application of spectrum -analysis to the stars. We can recognize from the spectrum -different stages in the process of cooling, and in some of the -fainter stars we perceive indeed that chemical compounds -have already formed, and still exist. As to new stars, again, -says Vögel, Zöllner’s theory seems in nowise contradicted -“by the spectral observations made on the two new stars of -1866 and 1876. The bright continuous spectrum, and the -bright lines only slightly exceeding it at first” (a description, -however, applying correctly only to the star of 1876), “could -not be well explained if we only suppose a violent eruption -from the interior, which again rendered the surface wholly -or partially luminous; but are easily explained if we suppose -that the quantity of light is considerably augmented through<span class="pagenum"><a id="Page_125">125</a></span> -a simultaneous process of combustion. If this process is of -short duration, then the continuous spectrum, as was the -case with the new star of 1876, will very quickly decrease in -intensity down to a certain limit, while the bright lines in the -spectrum, which result from the incandescent gases that -have emanated in enormous quantities from the interior, will -continue for some time.”</p> - -<p>It thus appears that Herr Vögel regarded the observations -which had been made on this remarkable star up to -March 10 as indicating that first there had been an outburst -of glowing gaseous matter from the interior, producing the -part of the light which gave the bright lines indicative of -gaseity, and that then there had followed, as a consequence, -the combustion of a portion of the solid and relatively cool -crust, causing the continuous part of the spectrum. We -may compare what had taken place, on this hypothesis, with -the outburst of intensely hot gases from the interior of a -volcanic crater, and the incandescence of the lips of the -crater in consequence of the intense heat of the out-rushing -gases. Any one viewing such a crater from a distance, with -a spectroscope, would see the bright lines belonging to the -out-rushing gases superposed upon the continuous spectrum -due to the crater’s burning lips. Vögel further supposes -that the burning parts of the star soon cooled, the majority -of the remaining light (or at any rate the part of the remaining -light spectroscopically most effective) being that -which came from the glowing gases which had emanated in -vast quantities from the star’s interior.</p> - -<p>“The observations of the spectrum show, beyond doubt,” -he says, “that the decrease in the light of the star corresponds -with the cooling of its surface. The violet and blue -parts decreased more rapidly in intensity than the other -parts; and the absorption-bands which crossed the spectrum -have gradually become darker and darker.”</p> - -<p>The reasoning, however, if not altogether unsatisfactory, -is by no means so conclusive as Herr Vögel appears to think. -It is not clear how the incandescent portion of the surface<span class="pagenum"><a id="Page_126">126</a></span> -could possibly cool in any great degree while enormous -quantities of gas more intensely heated (by the hypothesis) -remained around the star. The more rapid decrease in the -violet and blue parts of the spectrum than in the red and -orange is explicable as an effect of absorption, at least as -readily as by the hypothesis that burning solid or liquid -matter had cooled. Vögel himself could only regard the -other bands which crossed the spectrum as absorption-bands. -And the absorption of light from the continuous spectrum -in these parts (that is, not where the bright lines belonging -to the gaseous matter lay) could not possibly result from -absorption produced by those gases. If other gases were -in question, gases which, by cooling with the cooling surface, -had become capable of thus absorbing light from special -parts of the spectrum, how is it that before, when these -gases were presumably intensely heated, they did not indicate -their presence by bright bands? Bright bands, indeed, -were seen, which eventually faded out of view, but -these bright bands did not occupy the position where, later -on, absorption-bands appeared.</p> - -<p>The natural explanation of what had thus far been observed -is different from that advanced by Vögel, though we -must not assume that because it is the natural, it is necessarily -the true explanation. It is this—that the source of that -part of the star’s light which gave the bright-line spectrum, -or the spectrum indicative of gaseity, belongs to the normal -condition of the star, and not to gases poured forth, in consequence -of some abnormal state of things, from the sun’s -interior. We should infer naturally, though again I say not -<em>therefore</em> correctly, that if a star spectroscope had been -directed upon the place occupied by the new star before -it began to shine with unusual splendour, the bright-line -spectrum would have been observed. Some exceptional -cause would then seem to have aroused the entire surface -of the star to shine with a more intense brightness, the -matter thus (presumably) more intensely heated being such -as would give out the combined continuous and bright-line<span class="pagenum"><a id="Page_127">127</a></span> -spectrum, including the bright lines which, instead of fading -out, shone with at least relatively superior brightness as the -star faded from view. The theory that, on the contrary, -the matter giving these more persistent lines was that whose -emission caused the star’s increase of lustre, seems at least -not proven, and I would go so far as to say that it accords -ill with the evidence.</p> - -<p>The question, be it noted, is simply whether we should -regard the kind of light which lasts longest in this star as it -fades out of view as more probably belonging to the star’s -abnormal brightness or to its normal luminosity. It seems -to me there can be little doubt that the persistence of this -part of the star’s light points to the latter rather than to the -former view.</p> - -<p>Let it also be noticed that the changes which had been -observed thus far were altogether unlike those which had -been observed in the case of the star in the Northern Crown, -and therefore cannot justly be regarded as pointing to the -same explanation. As the star in the Crown faded from -view, the bright lines indicative of glowing hydrogen died -out, and only the ordinary stellar spectrum remained. In the -case of the star in the Swan, the part of the spectrum corresponding -to stellar light faded gradually from view, and bright -lines only were left, at least as conspicuous parts of the star’s -spectrum. So that whereas one orb seemed to have faded -into a faint star, the other seemed fading out into a nebula—not -merely passing into such a condition as to shine with -light indicative of gaseity, but actually so changing as to -shine with light of the very tints (or, more strictly, of the -very wave-lengths) observed in all the gaseous nebulæ.</p> - -<p>The strange eventful history of the new star in Cygnus -did not end here, however. We may even say, indeed, -that it has not ended yet. But another chapter can already -be written.</p> - -<p>Vögel ceased from observing the star in March, precisely -when observation seemed to promise the most interesting -results. At most other observatories, also, no observations<span class="pagenum"><a id="Page_128">128</a></span> -were made for about half a year. At the Dunecht Observatory<a id="FNanchor_17" href="#Footnote_17" class="fnanchor">17</a> -pressure of work relating to Mars interfered with the -prosecution of those observations which had been commenced -early in the year. But on September 3, Lord -Lindsay’s 15-inch reflector was directed upon the star. A -star was still shining where the new star’s yellow lustre had -been displayed in November, 1876; but now the star shone -with a faint blue colour. Under spectroscopic examination, -however, the light from this seeming blue star was -found not to be starlight, properly speaking, at all. It -formed no rainbow-tinted spectrum, but gave light of only -a single colour. The single line now seen was that which -at the time of Vögel’s latest observation had become the -strongest of the bright lines of the originally complex -spectrum of the so-called new star. It is the brightest of -the lines given by the gaseous nebulæ. In fact, if nothing -had been known about this body before the spectroscopic -observation of September 3 was made, the inference from -the spectrum given by the blue star would undoubtedly have -been that the object is in reality a small nebula of the -planetary sort, very similar to that one close by the pole of -the ecliptic, which gave Huggins the first evidence of the -gaseity of nebulæ, but very much smaller. I would specially -direct the reader’s attention, in fact, to Huggins’s account -of his observation of that planetary nebula in the Dragon. -“On August 19, 1864,” he says, “I directed the telescope -armed with the spectrum apparatus to this nebula. At first -I suspected some derangement of the instrument had taken -place, for no spectrum was seen, but only” a single line of -light. “I then found that the light of this nebula, unlike -any other extra-terrestrial light which had yet been subjected -by me to prismatic analysis, was not composed of -light of different refrangibilities, and therefore could not -form a spectrum. A great part of the light from this nebula<span class="pagenum"><a id="Page_129">129</a></span> -is monochromatic, and after passing through the prisms -remains concentrated in a bright line.” A more careful -examination showed that not far from the bright line was -a much fainter line; and beyond this, again, a third exceedingly -faint line was seen. The brightest of the three -lines was a line of nitrogen corresponding in position with -the brightest of the lines in the spectrum of our own air. -The faintest corresponded in position with a line of hydrogen. -The other has not yet been associated with a known line -of any element. Besides the faint lines, Dr. Huggins perceived -an exceedingly faint continuous spectrum on both -sides of the group of bright lines; he suspected, however, -that this faint spectrum was not continuous, but crossed by -dark spaces. Later observations on other nebulæ induced -him to regard this faint continuous spectrum as due to the -solid or liquid matter of the nucleus, and as quite distinct -from the bright lines into which nearly the whole of the -light from the nebula is concentrated. The fainter parts of -the spectrum of the gaseous nebulæ, in fact, correspond to -those parts of the spectrum of the “new star” in Cygnus -which last remained visible, before the light assumed its -present monochromatic colour.</p> - -<p>Now let us consider the significance of the evidence -afforded by this discovery—not perhaps hoping at once -to perceive the full meaning of the discovery, but endeavouring -to advance as far as we safely can in the direction -in which it seems to point.</p> - -<p>We have, then, these broad facts: where no star had -been known, an object has for a while shone with stellar -lustre, in this sense, that its light gave a rainbow-tinted -spectrum not unlike that which is given by a certain -order of stars; this object has gradually parted with its -new lustre, and in so doing the character of its spectrum -has slowly altered, the continuous portion becoming fainter, -and the chief lustre of the bright-line portion shifting from -the hydrogen lines to a line which, there is every reason to -believe, is absolutely identical with the nebula nitrogen line:<span class="pagenum"><a id="Page_130">130</a></span> -and lastly, the object has ceased to give any perceptible -light, other than that belonging to this nitrogen line.</p> - -<p>Now it cannot, I think, be doubted that, accompanying -the loss of lustre in this orb, there has been a corresponding -loss of heat. The theory that all the solid and liquid -materials of the orb have been vaporized by intense heat, -and that this vaporization has caused the loss of the star’s -light (as a lime-light might die out with the consumption -of the lime, though the flame remained as hot as ever), -is opposed by many considerations. It seems sufficient to -mention this, that if a mass of solid matter, like a dead -sun or planet, were exposed to an intense heat, first raising -it to incandescence, and eventually altogether vaporizing -its materials, although quite possibly the time of its intensest -lustre might precede the completion of the vaporization, -yet certainly so soon as the vaporization was complete, -the spectrum of the newly vaporized mass would show -multitudinous bright lines corresponding to the variety of -material existing in the body. No known fact of spectroscopic -analysis lends countenance to the belief that a -solid or liquid mass, vaporized by intense heat, would shine -thenceforth with monochromatic light.</p> - -<p>Again, I think we are definitely compelled to abandon -Vögel’s explanation of the phenomena by Zöllner’s theory. -The reasons which I have urged above are not only -strengthened severally by the change which has taken place -in the spectrum of the new star since Vögel observed it, but -an additional argument of overwhelming force has been -introduced. If any one of the suns died out, a crust forming -over its surface and this crust being either absolutely -dark or only shining with very feeble lustre, the sun would -still in one respect resemble all the suns which are spread -over the heavens—it would show no visible disc, however -great the telescopic power used in observing it. If the -nearest of all the stars were as large, or even a hundred -times as large, as Sirius, and were observed with a telescope -of ten times greater magnifying power than any yet<span class="pagenum"><a id="Page_131">131</a></span> -directed to the heavens, it would appear only as a point of -light. If it lost the best part of its lustre, it would appear -only as a dull point of light. Now the planetary -nebulæ show discs, sometimes of considerable breadth. -Sir J. Herschel, to whom and to Sir W. Herschel we owe -the discovery and observation of nearly all these objects, -remarks that “the planetary nebulæ have, as their name -imports, a near, in some instances a perfect, resemblance -to planets, presenting discs round, or slightly oval, in -some quite sharply terminated, in others a little hazy or -softened at the borders....” Among the most remarkable -may be specified one near the Cross, whose light is -about equal to that of a star just visible to the naked eye, -“its diameter about twelve seconds, its disc circular or very -slightly elliptic, and with a clear, sharp, well-defined outline, -having exactly the appearance of a planet, with the exception -of its colour, which is a fine and full blue, verging -somewhat upon green.” But the largest of these planetary -nebulæ, not far from the southernmost of the two stars called -the Pointers, has a diameter of 2⅔ minutes of arc, “which, -supposing it placed at a distance from us not greater than -that of the nearest known star of our northern heavens, -would imply a linear diameter seven times greater than that -of the orbit of Neptune.” The actual volume of this -object, on this assumption, would exceed our sun’s ten -million million times. No one supposes that this planetary -nebula, shining with a light indicative of gaseity, has a mass -exceeding our sun’s in this enormous degree. It probably -has so small a mean density as not greatly to exceed, or -perhaps barely to equal, our sun in mass. Now though the -“new star” in Cygnus presented no measurable disc, and -still shines as a mere blue point in the largest telescope, yet -inasmuch as its spectrum associated it with the planetary and -gaseous nebulæ, which we know to be much larger bodies -than the stars, it must be regarded, in its present condition, -as a planetary nebula, though a small one; and since we -cannot for a moment imagine that the monstrous planetary<span class="pagenum"><a id="Page_132">132</a></span> -nebulæ just described are bodies which once were suns, but -whose crust has now become non-luminous, while around -the crust masses of gas shine with a faint luminosity, so -are we precluded from believing that this smaller member -of the same family is in that condition.</p> - -<p>It <em>is</em> conceivable (and the possibility must be taken into -account in any attempt to interpret the phenomena of the -new star) that when shining as a star, the new orb, so far as -this unusual lustre was concerned, was of sunlike dimensions. -For we cannot tell whether the surface which gave the strong -light was less or greater than, or equal to, that which is now -shining with monochromatic light. Very likely, if we had -been placed where we could have seen the full dimensions of -the planetary nebula as it at present exists, we should have -found only its nuclear part glowing suddenly with increased -lustre, which, after very rapidly attaining its maximum, -gradually died out again, leaving the nebula as it had been -before. But that the mass now shining with monochromatic -light is, I will not say enormously large, but of exceedingly -small mean density, so that it is enormously large compared -with the dimensions it would have if its entire substance -were compressed till it had the same mean density as our -own sun, must be regarded as, to all intents and purposes, -certain.</p> - -<p>We certainly have not here, then, the case of a sun -which has grown old and dead and dark save at the surface, -but within whose interior fire has still remained, only waiting -some disturbing cause to enable it for a while to rush forth. -If we could suppose that in such a case there <em>could</em> be such -changes as the spectroscope has indicated—that the bright -lines of the gaseous outbursting matter would, during the -earlier period of the outburst, show on a bright continuous -background, due to the glowing lips of the opening through -which the matter had rushed, but later would shine alone, -becoming also fewer in number, till at last only one was left,—we -should find ourselves confronted with the stupendous -difficulty that that single remaining line is the bright line of<span class="pagenum"><a id="Page_133">133</a></span> -the planetary and other gaseous nebulæ. Any hypothesis -accounting for its existence in the spectrum of the faint blue -starlike object into which the star in Cygnus has faded ought -to be competent to explain its existence in the spectrum of -those nebulæ. But <em>this</em> hypothesis certainly does not so -explain its existence in the nebular spectrum. The nebulæ -cannot be suns which have died out save for the light of -gaseous matter surrounding them, for they are millions, or -rather millions of millions, of times too large. If, for instance, -a nebula, like the one above described as lying near -the southernmost Pointer, were a mass of this kind, having -the same mean density as the sun, and lying only at the -distance of the nearest of the stars from us, then not only -would it have the utterly monstrous dimensions stated by Sir -J. Herschel, but it would in the most effective way perturb the -whole solar system. With a diameter exceeding seven times -that of the orbit of Neptune, it would have a volume, and -therefore a mass, exceeding our sun’s volume and mass -more than eleven millions of millions of times. But its distance -on this assumption would be only about two hundred -thousand times the sun’s, and its attraction reduced, as -compared with his, on this account only forty thousand -millions of times. So that its attraction on the sun and -on the earth would be greater than his attraction on the -earth, in the same degree that eleven millions are greater -than forty thousand—or two hundred and seventy-five times. -The sun, despite his enormous distance from such a mass, -would be compelled to fall very quickly into it, unless he -circuited (with all his family) around it in about one-sixteenth -of a year, which most certainly he does not do. Nor -would increasing the distance at which we assume the star -to lie have any effect to save the sun from being thus perturbed, -but the reverse. If we double for instance our estimate -of the nebula’s distance, we increase eightfold our -estimate of its mass, while we only diminish its attraction on -our sun fourfold on account of increased distance; so that -now its attraction on our sun would be one-fourth its former<span class="pagenum"><a id="Page_134">134</a></span> -attraction multiplied by eight, or twice our former estimate. -We cannot suppose the nebula to be much nearer than -the nearest star. Again, we cannot suppose that the light -of these gaseous nebulæ comes from some bright orb within -them of only starlike apparent dimensions, for in that case -we should constantly recognize such starlike nucleus, which -is not the case. Moreover, the bright-line spectrum from -one of these nebulæ comes from the whole nebula, as is -proved by the fact that if the slit of the spectroscope be -opened it becomes possible to see three spectroscopic -images of the nebula itself, not merely the three bright lines.</p> - -<p>So that, if we assume the so-called star in Cygnus to -be now like other objects giving the same monochromatic -spectrum—and this seems the only legitimate assumption—we -are compelled to believe that the light now reaching us -comes from a nebulous mass, not from the faintly luminous -envelope of a dead sun. Yet, remembering that when at its -brightest this orb gave a spectrum resembling in general -characteristics that of other stars or suns, and closely resembling -even in details that of stars like Gamma Cassiopeiæ, -we are compelled by parity of reasoning to infer that -when the so-called new star was so shining, the greater -part of its light came from a sunlike mass. Thus, then, -we are led to the conclusion that in the case of this body -we have a nucleus or central mass, and that around this -central mass there is a quantity of gaseous matter, -resembling in constitution that which forms the bulk of the -other gaseous nebulæ. The denser nucleus ordinarily shines -with so faint a lustre that the continuous spectrum from its -light is too faint to be discerned with the same spectroscopic -means by which the bright lines of the gaseous portion are -shown; and the gaseous portion ordinarily shines with so -faint a lustre that its bright lines would not be discernible -on the continuous background of a stellar spectrum. -Through some cause unknown—possibly (as suggested in -an article on the earlier history of this same star in my -“Myths and Marvels of Astronomy”) the rush of a rich<span class="pagenum"><a id="Page_135">135</a></span> -and dense flight of meteors upon the central mass—the -nucleus was roused to a degree of heat far surpassing its -ordinary temperature. Thus for a time it glowed as a sun. -At the same time the denser central portions of the nebulous -matter were also aroused to intenser heat, and the bright -lines which ordinarily (and certainly at present) would not -stand out bright against the rainbow-tinted background of a -stellar spectrum, showed brightly upon the continuous spectrum -of the new star. Then as the rush of meteors upon -the nucleus and on the surrounding nebulous matter ceased—if -that be the true explanation of the orb’s accession of -lustre—or as the cause of the increase of brightness, whatever -that cause may have been, ceased to act, the central -orb slowly returned to its usual temperature, the nebulous -matter also cooling, the continuous spectrum slowly fading -out, the denser parts of the nebulous matter exercising also -a selective absorption (explaining the bands seen in the -spectrum at this stage) which gradually became a continuous -absorption—that is, affected the entire spectrum. Those -component gases, also, of the nebulous portion which had -for a while been excited to sufficient heat to show their -bright lines, cooled until their lines disappeared, and none -remained visible except for a while the three usual nebular -lines, and latterly (owing to still further cooling) only the -single line corresponding to the monochromatic light of the -fainter gaseous nebulæ.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_136">136</a></span></p> - -<div class="chapter"> -<h2><a id="STAR-GROUPING_STAR-DRIFT_AND_STAR-MIST"></a><i>STAR-GROUPING, STAR-DRIFT, AND STAR-MIST.</i><br /> - -<span class="subhead"><i>A Lecture delivered at the Royal Institution on May 6, 1870.</i></span></h2> -</div> - -<p class="in0">Nearly a century has passed since the greatest astronomer -the world has ever known—the Newton of observational -astronomy, as he has justly been called by Arago—conceived -the daring thought that he would gauge the -celestial depths. And because in his day, as indeed in our -own, very little was certainly known respecting the distribution -of the stars, he was forced to found his researches upon -a guess. He supposed that the stars, not only those visible -to the naked eye, but all that are seen in the most powerful -telescopes, are suns, distributed with a certain general -uniformity throughout space. It is my purpose to attempt -to prove that—as Sir Wm. Herschel was himself led to -suspect during the progress of his researches—this guess was -a mistaken one; that but a small proportion of the stars can -be regarded as real suns; and that in place of the uniformity -of distribution conceived by Sir Wm. Herschel, the chief -characteristic of the sidereal system is <em>infinite variety</em>.</p> - -<p>In order that the arguments on which these views are -based may be clearly apprehended, it will be necessary to -recall the main results of Sir Wm. Herschel’s system of -star-grouping.</p> - -<p>Directing one of his 20-feet reflectors to different parts of<span class="pagenum"><a id="Page_137">137</a></span> -the heavens, he counted the stars seen in the field of view. -Assuming that the telescope really reached the limits of the -sidereal system, it is clear that the number of stars seen -in any direction affords a means of estimating the relative -extension of the system in that direction, provided always -that the stars are really distributed throughout the system -with a certain approach to uniformity. Where many stars -are seen, there the system has its greatest extension; where -few, there the limits of the system must be nearest to us.</p> - -<p>Sir Wm. Herschel was led by this process of star-grouping -to the conclusion that the sidereal system has the figure -of a cloven disc. The stars visible to the naked eye lie far -within the limits of this disc. Stars outside the relatively -narrow limits of the sphere including all the visible stars, are -separately invisible. But where the system has its greatest -extension these orbs produce collectively the diffused light -which forms the Milky Way.</p> - -<p>Sir John Herschel, applying a similar series of researches -to the southern heavens, was led to a very similar conclusion. -His view of the sidereal system differs chiefly in this respect -from his father’s, that he considered the stars within certain -limits of distance from the sun to be spread less richly -through space than those whose united lustre produces -the milky light of the galaxy.</p> - -<p>Now it is clear that if the supposition on which these -views are based is just, the three following results are to be -looked for.</p> - -<p>In the first place, the stars visible to the naked eye would -be distributed with a certain general uniformity over the -celestial sphere; so that if on the contrary we find certain -extensive regions over which such stars are strewn much -more richly than over the rest of the heavens, we must -abandon Sir Wm. Herschel’s fundamental hypothesis and all -the conclusions which have been based upon it.</p> - -<p>In the second place, we ought to find no signs of the -aggregation of lucid stars into streams or clustering groups. -If we should find such associated groups, we must abandon<span class="pagenum"><a id="Page_138">138</a></span> -the hypothesis of uniform distribution and all the conclusions -founded on it.</p> - -<p>Thirdly, and most obviously of all, the lucid stars ought -not to be associated in a marked manner with the figure of -the Milky Way. To take an illustrative instance. When -we look through a glass window at a distant landscape we do -not find that the specks in the substance of the glass seem -to follow the outline of valleys, hills, trees, or whatever -features the landscape may present. In like manner, regarding -the sphere of the lucid stars as in a sense the window -through which we view the Milky Way, we ought not to find -these stars, which are so near to us, associated with the -figure of the Milky Way, whose light comes from distances -so enormously exceeding those which separate us from the -lucid stars. Here again, then, if there should appear signs -of such association, we must abandon the theory that the -sidereal system is constituted as Sir Wm. Herschel supposed.</p> - -<p>It should further be remarked that the three arguments -derived from these relations are independent of each other. -They are not as three links of a chain, any one of which -being broken the chain is broken. They are as three strands -of a triple cord. If one strand holds, the cord holds. It -may be shown that all three are to be trusted.</p> - -<p>It is not to be expected, however, that the stars as -actually seen should exhibit these relations, since far the -larger number are but faintly visible; so that the eye would -look in vain for the signs of law among them, even though -law may be there. What is necessary is that maps should -be constructed on a uniform and intelligible plan, and that -in these maps the faint stars should be made bright, and the -bright stars brighter.</p> - -<p>The maps exhibited during this discourse [since published -as my “Library Atlas”] have been devised for this -purpose amongst others. There are twelve of them, but -they overlap, so that in effect each covers a tenth part of -the heavens. There is first a north-polar map, then five -maps symmetrically placed around it; again, there is a<span class="pagenum"><a id="Page_139">139</a></span> -south-polar map, and five maps symmetrically placed round -that map; and these five so fit in with the first five as -to complete the enclosure of the whole sphere. In effect, -every map of the twelve has five maps symmetrically placed -around it and overlapping it.</p> - -<p>Since the whole heavens contain but 5932 stars visible -to the naked eye, each of the maps should contain on the -average about 593 stars. But instead of this being the case, -some of the maps contain many more than their just proportion -of stars, while in others the number as greatly falls -short of the average. One recognizes, by combining these -indications, the existence of a roughly circular region, rich -in stars, in the northern heavens, and of another, larger and -richer, in the southern hemisphere.</p> - -<p>To show the influence of these rich regions, it is only -necessary to exhibit the numerical relations presented by the -maps.</p> - -<p>The north-polar map, in which the largest part of the -northern rich region falls, contains no less than 693 lucid -stars, of which upwards of 400 fall within the half corresponding -to the rich region. Of the adjacent maps, two -contain upwards of 500 stars, while the remaining three -contain about 400 each. Passing to the southern hemisphere, -we find that the south-polar map, which falls wholly -within a rich region, contains no less than 1132 stars! One -of the adjacent maps contains 834 stars, and the four -others exhibit numbers ranging from 527 to 595.</p> - -<p>It is wholly impossible not to recognize so unequal a -distribution as exhibiting the existence of special laws of -stellar aggregation.</p> - -<p>It is noteworthy, too, that the greater Magellanic cloud -falls in the heart of the southern rich region. Were there -not other signs that this wonderful object is really associated -with the sidereal system, it might be rash to recognize this -relation as indicating the existence of a physical connection -between the Nubecula Major and the southern region rich -in stars. Astronomers have indeed so long regarded the<span class="pagenum"><a id="Page_140">140</a></span> -Nubeculæ as belonging neither to the sidereal nor to the -nebular systems, that they are not likely to recognize very -readily the existence of any such connection. Yet how -strangely perverse is the reasoning which has led astronomers -so to regard these amazing objects. Presented fairly, -that reasoning amounts simply to this: The Magellanic -clouds contain stars and they contain nebulæ; therefore -they are neither nebular nor stellar. Can perversity of -reasoning be pushed further? Is not the obvious conclusion -this, that since nebulæ and stars are <em>seen</em> to be intermixed -in the Nubeculæ, the nebular and stellar systems form in -reality but one complex system?</p> - -<p>As to the existence of star-streams and clustering aggregations, -we have also evidence of a decisive character. -There is a well-marked stream of stars running from near -Capella towards Monoceros. Beyond this lies a long dark -rift altogether bare of lucid orbs, beyond which again lies an -extensive range of stars, covering Gemini, Cancer, and the -southern parts of Leo. This vast system of stars resembles -a gigantic sidereal billow flowing towards the Milky Way as -towards some mighty shore-line. Nor is this description -altogether fanciful; since one of the most marked instances -of star-drift presently to be adduced refers to this very -region. These associated stars <em>are</em> urging their way towards -the galaxy, and that at a rate which, though seemingly slow -when viewed from beyond so enormous a gap as separates us -from this system, must in reality be estimated by millions of -miles in every year.</p> - -<p>Other streams and clustering aggregations there are -which need not here be specially described. But it is -worth noticing that all the well-marked streams recognized -by the ancients seem closely associated with the southern -rich region already referred to. This is true of the stars -forming the River Eridanus, the serpent Hydra, and the -streams from the water-can of Aquarius. It is also noteworthy -that in each instance a portion of the stream lies -outside the rich region, the rest within it; while all the<span class="pagenum"><a id="Page_141">141</a></span> -streams which lie on the same side of the galaxy tend -towards the two Magellanic clouds.</p> - -<p>Most intimate signs of association between lucid stars -and the galaxy can be recognized—(i.) in the part extending -from Cygnus to Aquila; (ii.) in the part from Perseus to -Monoceros; (iii.) over the ship Argo; and (iv.) near Crux -and the feet of Centaurus.</p> - -<p>Before proceeding to the subject of Star-drift, three -broad facts may be stated. They are, I believe, now -recognized for the first time, and seem decisive of the -existence of special laws of distribution among the stars:—</p> - -<p>First, the rich southern region, though covering but a -sixth part of the heavens, contains one-third of all the lucid -stars, leaving only two-thirds for the remaining five-sixths of -the heavens.</p> - -<p>Secondly, if the two rich regions and the Milky Way be -considered as one part of the heavens, the rest as another, -then the former part is three times as richly strewn with lucid -stars as the second.</p> - -<p>Thirdly, the southern hemisphere contains one thousand -more lucid stars than the northern, a fact which cannot but -be regarded as most striking when it is remembered that the -total number of stars visible to ordinary eyesight in both -hemispheres falls short of 6000.</p> - -<p>Two or three years ago, the idea suggested itself to me -that if the proper motions of the stars were examined, they -would be found to convey clear information respecting the -existence of variety of structure, and special laws of distribution -within the sidereal system.</p> - -<p>In the first place, the mere amount of a star’s apparent -motion must be regarded as affording a means of estimating -the star’s distance. The nearer a moving object is, the -faster it will seem to move, and <i xml:lang="la" lang="la">vice versâ</i>. Of course in -individual instances little reliance can be placed on this -indication; but by taking the average proper motions of a -set of stars, a trustworthy measure may be obtained of their -average distance, as compared with the average distance of -another set.</p> - -<p><span class="pagenum"><a id="Page_142">142</a></span> -For example, we have in this process the means of -settling the question whether the apparent brightness of a -star is indeed a test of relative nearness. According to -accepted theories the sixth-magnitude stars are ten or twelve -times as far off as those of the first magnitude. Hence their -motions should, on the average, be correspondingly small. -Now, to make assurance doubly sure, I divided the stars into -two sets, the first including the stars of the 1st, 2nd, and 3rd, -the second including those of the 4th, 5th, and 6th magnitude. -According to accepted views, the average proper motion for -the first set should be about five times as great as that for -the second. I was prepared to find it about three times as -great; that is, not so much greater as the accepted theories -require, but still considerably greater. To my surprise, I -found that the average proper motion of the brighter orders -of stars is barely equal to that of the three lower orders.</p> - -<p>This proves beyond all possibility of question that by far -the greater number of the fainter orders of stars (I refer here -throughout to lucid stars) owe their faintness not to vastness -of distance, but to real relative minuteness.</p> - -<p>To pass over a number of other modes of research, the -actual mapping of the stellar motions, and the discovery of -the peculiarity to which I have given the name of star-drift, -remain to be considered.</p> - -<p>In catalogues it is not easy to recognize any instances of -community of motion which may exist among the stars, -owing to the method in which the stars are arranged. What -is wanted in this case (as in many others which yet remain to -be dealt with) is the adoption of a plan by which such -relations may be rendered obvious to the eye. The plan I -adopted was to attach to each star in my maps a small arrow, -indicating the amount and direction of that star’s apparent -motion in 36,000 years (the time-interval being purposely -lengthened, as otherwise most of the arrows would have -been too small to be recognized). When this was done, -several well-marked instances of community of motion could -immediately be recognized.</p> - -<p><span class="pagenum"><a id="Page_143">143</a></span> -It is necessary to premise, however, that before the experiment -was tried, there were reasons for feeling very -doubtful whether it would succeed. A system of stars -might really be drifting athwart the heavens, and yet the -drift might be rendered unrecognizable through the intermixture -of more distant or nearer systems having motions of -another sort and seen accidentally in the same general -direction.</p> - -<p>This was found to be the case, indeed, in several -instances. Thus the stars in the constellation Ursa Major, -and neighbouring stars in Draco, exhibit two well-marked -directions of drift. The stars β, γ, δ, ε, and ζ of the Great -Bear, besides two companions of the last-named star, are -travelling in one direction, with equal velocity, and clearly -form one system. The remaining stars in the neighbourhood -are travelling in a direction almost exactly the reverse. But -even this relation, thus recognized in a region of diverse -motions, is full of interest. Baron Mädler, the well-known -German astronomer, recognizing the community of motion -between ζ Ursæ and its companions, calculated the cyclic -revolution of the system to be certainly not less than 7000 -years. But when the complete system of stars showing this -motion is considered, we get a cyclic period so enormous, -that not only the life of man, but the life of the human race, -the existence of our earth, nay, even the existence of the -solar system, must be regarded as a mere day in comparison -with that tremendous cycle.</p> - -<p>Then there are other instances of star-drift where, though -two directions of motion are not intermixed, the drifting -nature of the motion is not at once recognized, because -of the various distances at which the associated stars lie -from the eye.</p> - -<p>A case of this kind is to be met with in the stars -forming the constellation Taurus. It was here that Mädler -recognized a community of motion among the stars, but he -did not interpret this as I do. He had formed the idea -that the whole of the sidereal system must be in motion<span class="pagenum"><a id="Page_144">144</a></span> -around some central point; and for reasons which need -not here be considered, he was led to believe that in -whatever direction the centre of motion may lie, the stars -seen in that general direction would exhibit a community -of motion. Then, that he might not have to examine the -proper motions all over the heavens, he inquired in what -direction (in all probability) the centre of motion may be -supposed to lie. Coming to the conclusion that it must -lie towards Taurus, he examined the proper motions in that -constellation, and found a community of motion which led -him to regard Alcyone, the chief star of the Pleiades, as the -centre around which the sidereal system is moving. Had -he examined further he would have found more marked -instances of community of motion in other parts of the -heavens, a circumstance which would have at once compelled -him to abandon his hypothesis of a central sun in the -Pleiades, or at least to lay no stress on the evidence -derivable from the community of motion in Taurus.</p> - -<p>Perhaps the most remarkable instance of star-drift is that -observed in the constellations Gemini and Cancer. Here -the stars seem to set bodily towards the neighbouring part of -the Milky Way. The general drift in that direction is too -marked, and affects too many stars, to be regarded as by -any possibility referable to accidental coincidence.</p> - -<p>It is worthy of note that if the community of star-drift -should be recognized (or I prefer to say, <em>when</em> it is recognized), -astronomers will have the means of determining the -relative distances of the stars of a drifting system. For -differences in the apparent direction and amount of motion -can be due but to differences of distance and position, and -the determination of these differences becomes merely a -question of perspective.<a id="FNanchor_18" href="#Footnote_18" class="fnanchor">18</a></p> - -<p>Before long it is likely that the theory of star-drift will -be subjected to a crucial test, since spectroscopic analysis -affords the means of determining the stellar motions of<span class="pagenum"><a id="Page_145">145</a></span> -recess or approach. The task is a very difficult one, but -astronomers have full confidence that in the able hands of -Mr. Huggins it will be successfully accomplished. I await -the result with full confidence that it will confirm my views. -(See pages <a href="#Page_92">92–94</a> for the result.)</p> - -<div class="tb">* <span class="in2">* </span><span class="in2">* </span><span class="in2">* </span><span class="in2">*</span></div> - -<p>Turning to the subject of Star-mist, under which head I -include all orders of nebulæ, I propose to deal with but a -small proportion of the evidence I have collected to prove -that none of the nebulæ are external galaxies. That evidence -has indeed become exceedingly voluminous.</p> - -<p>I shall dwell, therefore, on three points only.</p> - -<p>First, as to the distribution of the nebulæ:—They are -not spread with any approach to uniformity over the heavens, -but are gathered into streams and clusters. The one great -law which characterizes their distribution is an avoidance of -the Milky Way and its neighbourhood. This peculiarity has, -strangely enough, been regarded by astronomers as showing -that there is no association between the nebulæ and the -sidereal system. They have forgotten that marked contrast -is as clear a sign of association as marked resemblance, and -has always been so regarded by logicians.</p> - -<p>Secondly, there are in the southern heavens two well-marked -streams of nebulæ. Each of these streams is associated -with an equally well-marked stream of stars. Each -intermixed stream directs its course towards a Magellanic -Cloud, one towards the Nubecula Minor, the other towards -the Nubecula Major. To these great clusters they flow, -like rivers towards some mighty lake. And within these -clusters, which are doubtless roughly spherical in form, there -are found intermixed in wonderful profusion, stars, star-clusters, -and all the orders of nebulæ. Can these coincidences -be regarded as accidental? And if not accidental, -is not the lesson they clearly teach us this, that nebulæ form -but portions of the sidereal system, associating themselves -with stars on terms of equality (if one may so speak), even if -single stars be not more important objects in the scale of<span class="pagenum"><a id="Page_146">146</a></span> -creation than these nebulous masses, which have been so -long regarded as equalling, if not outvying, the sidereal -system itself in extent?</p> - -<p>The third point to which I wish to invite attention is the -way in which in many nebulæ stars of considerable relative -brightness, and belonging obviously to the sidereal system, -are so associated with nebulous masses as to leave no doubt -whatever that these masses really cling around them. The -association is in many instances far too marked to be regarded -as the effect of accident.</p> - -<p>Among other instances<a id="FNanchor_19" href="#Footnote_19" class="fnanchor">19</a> may be cited the nebula round -the stars <i>c</i>¹ and <i>c</i>² in Orion. In this object two remarkable -nebulous nodules centrally surround two double stars. -Admitting the association here to be real (and no other -explanation can reasonably be admitted), we are led to interesting -conclusions respecting the whole of that wonderful -nebulous region which surrounds the sword of Orion. We -are led to believe that the other nebulæ in that region are -really associated with the fixed stars there; that it is not a -mere coincidence, for instance, that the middle star in the -belt of Orion is involved in nebula, or that the lowest star -of the sword is similarly circumstanced. It is a legitimate -inference from the evidence that all the nebulæ in this region -belong to one great nebulous group, which extends its -branches to these stars. As a mighty hand, this nebulous -region seems to gather the stars here into close association, -showing us, in a way there is no misinterpreting, that these -stars form one system.</p> - -<p>The nebula around the strange variable star, Eta Argûs, -is another remarkable instance of this sort. More than two -years ago I ventured to make two predictions about this -object. The first was a tolerably safe one. I expressed my -belief that the nebula would be found to be gaseous. After -Mr. Huggins’s discovery that the great Orion nebula is -gaseous, it was not difficult to see that the Argo nebula must<span class="pagenum"><a id="Page_147">147</a></span> -be so too. At any rate, this has been established by -Captain Herschel’s spectroscopic researches. The other -prediction was more venturesome. Sir John Herschel, -whose opinion on such points one would always prefer to -share, had expressed his belief that the nebula lies far out in -space beyond the stars seen in the same field of view. I -ventured to express the opinion that those stars are involved -in the nebula. Lately there came news from Australia that -Mr. Le Sueur, with the great reflector erected at Melbourne, -has found that the nebula has changed largely in shape -since Sir John Herschel observed it. Mr. Le Sueur accordingly -expressed his belief that the nebula lies <em>nearer</em> to us -than the fixed stars seen in the same field of view. More -lately, however, he has found that the star Eta Argûs is -shining with the light of burning hydrogen, and he expresses -his belief that the star has consumed the nebulous matter -near it. Without agreeing with this view, I recognize in it a -proof that Mr. Le Sueur now considers the nebula to be -really associated with the stars around it. My belief is that -as the star recovers its brilliancy observation will show that -the nebula in its immediate neighbourhood becomes brighter -(<em>not</em> fainter through being consumed as fuel). In fact, I am -disposed to regard the variations of the nebula as systematic, -and due to orbital motions among its various portions around -neighbouring stars.</p> - -<p>As indicative of other laws of association bearing on the -relations I have been dealing with, I may mention the circumstance -that red stars and variable stars affect the neighbourhood -of the Milky Way or of well-marked star-streams. -The constellation Orion is singularly rich in objects of this -class. It is here that the strange “variable” Betelgeux lies. -At present this star shows no sign of variation, but a few -years ago it exhibited remarkable changes. One is invited -to believe that the star may have been carried by its proper -motion into regions where there is a more uniform distribution -of the material whence this orb recruits its fires. It may be -that in the consideration of such causes of variation affecting<span class="pagenum"><a id="Page_148">148</a></span> -our sun in long past ages a more satisfactory explanation -than any yet obtained may be found of the problem -geologists find so perplexing—the former existence of a -tropical climate in places within the temperate zone, or even -near the Arctic regions.<a id="FNanchor_20" href="#Footnote_20" class="fnanchor">20</a></p> - -<div class="tb">* <span class="in2">* </span><span class="in2">* </span><span class="in2">* </span><span class="in2">*</span></div> - -<p>It remains that I should exhibit the general results to -which I have been led. It has seemed to many that my -views tend largely to diminish our estimate of the extent -of the sidereal system. The exact reverse is the case. -According to accepted views there lie within the range of -our most powerful telescopes millions of millions of suns. -According to mine the primary suns within the range of our -telescopes must be counted by tens of thousands, or by -hundreds of thousands at the outside. What does this -diminution of numbers imply but that the space separating -sun from sun is enormously greater than accepted theories -would permit? And this increase implies an enormous -increase in the estimate we are to form of the vital energies -of individual suns. For the vitality of a sun, if one may -be permitted the expression, is measured not merely by the -amount of matter over which it exercises control, but by -the extent of space within which that matter is distributed. -Take an orb a thousand times vaster than our sun, and -spread over its surface an amount of matter exceeding a -thousandfold the combined mass of all the planets of the -solar system:—So far as living force is concerned, the result -is—<em>nil</em>. But distribute that matter throughout a vast space -all round the orb:—That orb becomes at once fit to be the -centre of a host of dependent worlds. Again, according -to accepted theories, when the astronomer has succeeded -in resolving the milky light of a portion of the galaxy into -stars, he has in that direction, at any rate, reached the limits -of the sidereal system. According to my views, what he<span class="pagenum"><a id="Page_149">149</a></span> -has really done has been but to analyze a definite aggregation -of stars, a mere corner of that great system. Yet once -more, according to accepted views, thousands and thousands -of galaxies, external to the sidereal system, can be seen -with powerful telescopes. If I am right, the external star-systems -lie far beyond the reach of the most powerful -telescope man has yet been able to construct, insomuch -that perchance the nearest of the outlying galaxies may lie -a million times beyond the range even of the mighty mirror -of the great Rosse telescope.</p> - -<p>But this is little. Wonderful as is the extent of the -sidereal system as thus viewed, even more wonderful is its -infinite variety. We know how largely modern discoveries -have increased our estimate of the complexity of the planetary -system. Where the ancients recognized but a few -planets, we now see, besides the planets, the families of -satellites; we see the rings of Saturn, in which minute -satellites must be as the sands on the sea-shore for multitude; -the wonderful zone of asteroids; myriads on myriads -of comets; millions on millions of meteor-systems, gathering -more and more richly around the sun, until in his neighbourhood -they form the crown of glory which bursts into view -when he is totally eclipsed. But wonderful as is the variety -seen within the planetary system, the variety within the -sidereal system is infinitely more amazing. Besides the -single suns, there are groups and systems and streams of -primary suns; there are whole galaxies of minor orbs; -there are clustering stellar aggregations, showing every -variety of richness, of figure, and of distribution; there are -all the various forms of nebulæ, resolvable and irresolvable, -circular, elliptical, and spiral; and lastly, there are irregular masses -of luminous gas, clinging in fantastic convolutions -around stars and star-systems. Nor is it unsafe to assert -that other forms and variety of structure will yet be discovered, -or that hundreds more exist which we may never -hope to recognize.</p> - -<p>But lastly, even more wonderful than the infinite variety<span class="pagenum"><a id="Page_150">150</a></span> -of the sidereal system, is its amazing vitality. Instead of -millions of inert masses, we see the whole heavens instinct -with energy—astir with busy life. The great masses of -luminous vapour, though occupying countless millions of -cubic miles of space, are moved by unknown forces like -clouds before the summer breeze; star-mist is condensing -into clusters; star-clusters are forming into suns; streams -and clusters of minor orbs are swayed by unknown attractive -energies; and primary suns singly or in systems are pursuing -their stately path through space, rejoicing as giants to run -their course, extending on all sides the mighty arm of their -attraction, gathering from ever-new regions of space supplies -of motive energy, to be transformed into the various forms -of force—light and heat and electricity—and distributed -in lavish abundance to the worlds which circle round them.</p> - -<p>Truly may I say, in conclusion, that whether we regard -its vast extent, its infinite variety, or the amazing vitality -which pervades its every portion, the sidereal system is, of -all the subjects man can study, the most imposing and the -most stupendous. It is as a book full of mighty problems—of -problems which are as yet almost untouched by man, -of problems which it might seem hopeless for him to attempt -to solve. But those problems are given to him for solution, -and he <em>will</em> solve them, whenever he dares attempt to decipher -aright the records of that wondrous volume.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_151">151</a></span></p> - -<div class="chapter"> -<h2><a id="MALLETS_THEORY_OF_VOLCANOES"></a><i>MALLET’S THEORY OF VOLCANOES.</i></h2> -</div> - -<p class="in0">There are few subjects less satisfactorily treated in scientific -treatises than that which Humboldt calls the Reaction -of the Earth’s Interior. We find, not merely in the configuration -of the earth’s crust, but in actual and very -remarkable phenomena, evidence of subterranean forces of -great activity; and the problems suggested seem in no sense -impracticable: yet no theory of the earth’s volcanic energy -has yet gained general acceptance. While the astronomer -tells us of the constitution of orbs millions of times further -away than our own sun, the geologist has hitherto been -unable to give an account of the forces which agitate the -crust of the orb on which we live.</p> - -<p>The theory put forward respecting volcanic energy, however, -by the eminent seismologist Mallet, promises not -merely to take the place of all others, but to gain a degree -of acceptance which has not been accorded to any theory -previously enunciated. It is, in principle, exceedingly -simple, though many of the details (into which I do not -propose to enter) involve questions of considerable difficulty.</p> - -<p>Let us, in the first place, consider briefly the various -explanations which had been already advanced.</p> - -<p>There was first the chemical theory of volcanic energy, the -favourite theory of Sir Humphry Davy. It is possible to -produce on a small scale nearly all the phenomena due to -subterranean activity, by simply bringing together certain<span class="pagenum"><a id="Page_152">152</a></span> -substances, and leaving them to undergo the chemical changes -due to their association. As a familiar instance of explosive -action thus occasioned, we need only mention the results -experienced when any one unfamiliar with the methods of -treating lime endeavours over hastily to “slake” or “slack” -it with water. Indeed, one of the strong points of the -chemical theory consisted in the circumstance that volcanoes -only occur where water can reach the subterranean -regions—or, as Mallet expresses it, that “without water -there is no volcano.” But the theory is disposed of by the -fact, now generally admitted, that the chemical energies of -our earth’s materials were almost wholly exhausted before -the surface was consolidated.</p> - -<p>Another inviting theory is that according to which the -earth is regarded as a mere shell of solid matter surrounding -a molten nucleus. There is every reason to believe -that the whole interior of the earth is in a state of intense -heat; and if the increase of heat with depth (as shown in -our mines) is supposed to continue uniformly, we find that -at very moderate depths a degree of heat must prevail -sufficient to liquefy any known solids under ordinary conditions. -But the conditions under which matter exists a -few miles only below the surface of the earth are not -ordinary. The pressure enormously exceeds any which our -physicists can obtain experimentally. The ordinary distinction -between solids and liquids cannot exist at that -enormous pressure. A mass of cold steel could be as plastic -as any of the glutinous liquids, while the structural change -which a solid undergoes in the process of liquefying could -not take place under such pressure even at an enormously -high temperature. It is now generally admitted that if the -earth really has a molten nucleus, the solid crust must, -nevertheless, be far too thick to be in any way disturbed -by changes affecting the liquid matter beneath.</p> - -<p>Yet another theory has found advocates. The mathematician -Hopkins, whose analysis of the molten-nucleus -theory was mainly effective in showing that theory to be untenable,<span class="pagenum"><a id="Page_153">153</a></span> -suggested that there may be isolated subterranean -lakes of fiery matter, and that these may be the true seat of -volcanic energy. But such lakes could not maintain their -heat for ages, if surrounded (as the theory requires) by -cooler solid matter, especially as the theory also requires -that water should have access to them. It will be observed -also that none of the theories just described affords any -direct account of those various features of the earth’s surface—mountain -ranges, table-lands, volcanic regions, and so -on—which are undoubtedly due to the action of subterranean -forces. The theory advanced by Mr. Mallet is open -to none of these objections. It seems, indeed, competent -to explain all the facts which have hitherto appeared most -perplexing.</p> - -<p>It is recognized by physicists that our earth is gradually -parting with its heat. As it cools it contracts. Now if this -process of contraction took place uniformly, no subterranean -action would result. But if the interior contracts more -quickly than the crust, the latter must in some way or other -force its way down to the retreating nucleus. Mr. Mallet -shows that the hotter internal portion must contract faster -than the relatively cool crust; and then he shows that the -shrinkage of the crust is competent to occasion all the -known phenomena of volcanic action. In the distant ages -when the earth was still fashioning, the shrinkage produced -the <em>irregularities of level</em> which we recognize in the elevation -of the land and the depression of the ocean-bed. Then -came the period when as the crust shrank it formed <em>corrugations</em>, -in other words, when the foldings and elevations -of the somewhat thickened crust gave rise to the mountain-ranges -of the earth. Lastly, as the globe gradually lost its -extremely high temperature, the continuance of the same -process of shrinkage led no longer to the formation of ridges -and table-lands, but to local crushing-down and dislocation. -This process is still going on, and Mr. Mallet not only -recognizes here the origin of earthquakes, and of the -changes of level now in progress, but the true cause of<span class="pagenum"><a id="Page_154">154</a></span> -volcanic heat. The modern theory of heat as a form of -motion here comes into play. As the solid crust closes in -upon the shrinking nucleus, the work expended in crushing -down and dislocating the parts of the crust is transformed -into heat, by which, at the places where the process goes -on with greatest energy, “the materials of the rock so -crushed and of that adjacent to it are heated even to fusion. -The access of water to such points determines volcanic -eruption.”</p> - -<p>Now all this is not mere theorising. Mr. Mallet does -not come before the scientific world with an ingenious -speculation, which may or may not be confirmed by observation -and experiment. He has measured and weighed -the forces of which he speaks. He is able to tell precisely -what proportion of the actual energy which must be developed -as the earth contracts is necessary for the production -of observed volcanic phenomena. It is probable -that nine-tenths of those who have read these lines would -be disposed to think that the contraction of the earth must -be far too slow to produce effects so stupendous as those -which we recognize in the volcano and the earthquake. -But Mr. Mallet is able to show, by calculations which cannot -be disputed, that less than one-fourth of the heat at -present annually lost by the earth is sufficient to account for -the total annual volcanic action, according to the best data -at present in our possession.</p> - -<p>As I have said, I do not propose to follow out Mr. -Mallet’s admirable theory into all its details. I content -myself with pointing out how excellently it accounts for -certain peculiarities of the earth’s surface configuration. -Few that have studied carefully drawn charts of the chief -mountain-ranges can have failed to notice that the arrangement -of these ranges does not accord with the idea of -upheaval through the action of internal forces. But it -will be at once recognized that the aspect of the mountain-ranges -accords exactly with what would be expected -to result from such a process of contraction as Mr. Mallet<span class="pagenum"><a id="Page_155">155</a></span> -has indicated. The shrivelled skin of an apple affords no -inapt representation of the corrugated surface of our earth, -and according to the new theory, the shrivelling of such -a skin is precisely analogous to the processes at work upon -the earth when mountain-ranges were being formed. Again, -there are few students of geology who have not found a -source of perplexity in the foldings and overlappings of -strata in mountainous regions. No forces of upheaval seem -competent to produce this arrangement. But by the new -theory this feature of the earth’s surface is at once explained; -indeed, no other arrangement could be looked for.</p> - -<p>It is worthy of notice that Mr. Mallet’s theory of Volcanic -energy is completely opposed to ordinary ideas -respecting earthquakes and volcanoes. We have been -accustomed vaguely to regard these phenomena as due to -the eruptive outbursting power of the earth’s interior; we -shall now have to consider them as due to the subsidence -and shrinkage of the earth’s exterior. Mountains have not -been upheaved, but valleys have sunk down. And in -another respect the new theory tends to modify views which -have been generally entertained in recent times. Our most -eminent geologists have taught that the earth’s internal -forces may be as active now as in the epochs when the -mountain-ranges were formed. But Mr. Mallet’s theory -tends to show that the volcanic energy of the earth is a -declining force. Its chief action had already been exerted -when mountains began to be formed; what remains now -is but the minutest fraction of the volcanic energy of the -mountain-forming era; and each year, as the earth parts -with more and more of its internal heat, the sources of her -subterranean energy are more and more exhausted. The -thought once entertained by astronomers that the earth -might explode like a bomb, her scattered fragments producing -a ring of bodies resembling the zone of asteroids, -seems further than ever from probability; if ever there was -any danger of such a catastrophe, the danger has long since -passed away.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_156">156</a></span></p> - -<div class="chapter"> -<h2><a id="TOWARDS_THE_NORTH_POLE"></a><i>TOWARDS THE NORTH POLE.</i></h2> -</div> - -<p class="in0">The Arctic Expedition which returned to our shores in the -autumn of 1876 may be regarded as having finally decided -the question whether the North Pole of the earth is accessible -by the route through Smith’s Sound—a route which -may conveniently and properly be called the American route. -Attacks may hereafter be made on the Polar fastness from -other directions; but it is exceedingly unlikely that this -country, at any rate, will again attempt to reach the Pole -along the line of attack followed by Captain Nares’s expedition. -I may be forgiven, perhaps, for regarding Arctic -voyages made by the seamen of other nations as less likely -to be successful than those made by my own countrymen. -It is not mere national prejudice which suggests this opinion. -It is the simple fact that hitherto the most successful approaches -towards both the Northern and the Southern -Poles have been made by British sailors. Nearly a quarter -of a century has passed since Sir E. Parry made the nearest -approach to the North Pole recorded up to that time; and -although, in the interval between Parry’s expedition and -Nares’s, no expedition had been sent out from our shores -with the object of advancing towards the Pole, while -America, Sweden, Russia, and Germany sent out several, -Parry’s attempt still remained unsurpassed and unequalled. -At length it has been surpassed, but it has been by his own -countrymen. In like manner, no nation has yet succeeded -in approaching the Antarctic Pole so nearly, within many -miles, as did Captain Sir J. C. Ross in 1844. Considering<span class="pagenum"><a id="Page_157">157</a></span> -these circumstances, and remembering the success which -rewarded the efforts of Great Britain in the search for the -North-West Passage, it cannot be regarded as national prejudice -to assert that events indicate the seamen of this -country as exceptionally fitted to contend successfully -against the difficulties and the dangers of Arctic exploration. -Should England, then, give up the attempt to reach -the North Pole by way of Smith’s Sound and its northerly -prolongation, it may fairly be considered unlikely that the -Pole will ever be reached in that direction.</p> - -<p>It may be well to examine the relative probable chances -of success along other routes which have either not been so -thoroughly tried, or have been tried under less favourable -conditions.</p> - -<p>Passing over the unfortunate expedition under Hugh -Willoughby in 1553, the first attempt to penetrate within the -Polar domain was made by Henry Hudson in 1607. The -route selected was one which many regard (and I believe -correctly) as the one on which there is the best chance of -success; namely, the route across the sea lying to the west -of Spitzbergen. That Hudson, in the clumsy galleons of -Elizabeth’s time, should have penetrated to within eight -degrees and a half of the Pole, or to a distance only exceeding -Nares’s nearest approach by about 130 miles, proves -conclusively, we think, that with modern ships, and especially -with the aid of steam, this route might be followed with -much better prospect of success than that which was adopted -for Nares’s expedition. If the reader will examine a map of -the Arctic regions he will find that the western shores of -Spitzbergen and the north-eastern shores of Greenland, as -far as they have been yet explored, are separated by about -33 degrees of longitude, equivalent on the 80th parallel of -latitude to about 335 miles. Across the whole breadth of -this sea Arctic voyagers have attempted to sail northwards -beyond the 80th parallel, but no one has yet succeeded in -the attempt except on the eastern side of that sea. It was -here that Hudson—fortunately for him—directed his attack;<span class="pagenum"><a id="Page_158">158</a></span> -and he passed a hundred miles to the north of the 80th -parallel, being impeded and finally stopped by the packed -ice around the north-western shores of Spitzbergen.</p> - -<p>Let us consider the fortunes of other attempts which -have been made to approach the Pole in this direction.</p> - -<p>In 1827 Captain (afterwards Sir Edward) Parry, who had -already four times passed beyond the Arctic Circle—viz., in -1818, 1819, 1821–23, and 1824–25—made an attempt to -reach the North Pole by way of Spitzbergen. His plan was -to follow Hudson’s route until stopped by ice; then to leave -his ship, and cross the ice-field with sledges drawn by Esquimaux -dogs, and, taking boats along with the party, to cross -whatever open water they might find. In this way he succeeded -in reaching latitude 82° 45´ north, the highest ever -attained until Nares’s expedition succeeded in crossing the -83rd parallel. Parry found that the whole of the ice-field -over which his party were laboriously travelling northwards -was being carried bodily southwards, and that at length the -distance they were able to travel in a day was equalled by -the southerly daily drift of the ice-field, so that they made -no real progress. He gave up further contest, and returned -to his ship the <i>Hecla</i>.</p> - -<p>It is important to inquire whether the southerly drift -which stopped Parry was due to northerly winds or to a -southerly current; and if to the latter cause, whether this -current probably affects the whole extent of the sea in which -Parry’s ice-field was drifting. We know that his party were -exposed, during the greater part of their advance from Spitzbergen, -to northerly winds. Now the real velocity of these -winds must have been greater than their apparent velocity, -because the ice-field was moving southwards. Had this not -been the case, or had the ice-field been suddenly stopped, -the wind would have seemed stronger; precisely as it seems -stronger to passengers on board a sailing vessel when, after -being before the wind for a time, she is brought across the -wind. The ice-field was clearly travelling before the wind, -but not nearly so fast as the wind; and therefore there is<span class="pagenum"><a id="Page_159">159</a></span> -good reason for believing that the motion of the ice-field -was due to the wind alone. If we suppose this to have been -really the case, then, as there is no reason for believing that -northerly winds prevail uniformly in the Arctic regions, we -must regard Parry’s defeat as due to mischance. Another -explorer might have southerly instead of northerly winds, -and so might be assisted instead of impeded in his advance -towards the Pole. Had this been Parry’s fortune, or even if -the winds had proved neutral, he would have approached -nearer to the Pole than Nares. For Parry reckoned that he -had lost more than a hundred miles by the southerly drift of -the ice-field, by which amount at least he would have advanced -further north. But that was not all; for there can be -little doubt that he would have continued his efforts longer -but for the Sisyphæan nature of the struggle. It is true he -was nearer home when he turned back than he would have -been but for the drift, and one of his reasons for turning -back was the consideration of the distance which his men -had to travel in returning. But he was chiefly influenced (so -far as the return journey was concerned) by the danger caused -by the movable nature of the ice-field, which might at any -time begin to travel northwards, or eastwards, or westwards.</p> - -<p>If we suppose that not the wind but Arctic currents -carried the ice-field southwards, we must yet admit the probability—nay, -almost the certainty—that such currents are -only local, and occupy but a part of the breadth of the -North Atlantic seas in those high latitudes. The general -drift of the North Atlantic surface-water is unquestionably -not towards the south but towards the north; and whatever -part we suppose the Arctic ice to perform in regulating the -system of oceanic circulation—whether, with Carpenter, we -consider the descent of the cooled water as the great moving -cause of the entire system of circulation, or assign to that -motion a less important office (which seems to me the juster -opinion)—we must in any case regard the Arctic seas as a -region of surface indraught. The current flowing from those -seas, which caused (on the hypothesis we are for the moment<span class="pagenum"><a id="Page_160">160</a></span> -adopting) the southwardly motion of Parry’s ice-field, must -therefore be regarded as in all probability an exceptional -phenomenon of those seas. By making the advance from a -more eastwardly or more westwardly part of Spitzbergen, -a northerly current would probably be met with; or rather, -the motion of the ice-field would indicate the presence of -such a current, for I question very much whether open -water would anywhere be found north of the 83rd parallel. -In that case, a party might advance in one longitude and -return in another, selecting for their return the longitude in -which (always according to our present hypothesis that -currents caused the drift) Parry found that a southerly current -underlay his route across the ice. On the whole, however, -it appears to me more probable that winds, not currents, -caused the southerly drift of Parry’s ice-field.</p> - -<p>In 1868, a German expedition, under Captain Koldewey, -made the first visit to the seas west of Spitzbergen in a steamship, -the small but powerful screw steamer <i>Germania</i> (126 -tons), advancing northwards a little beyond the 81st parallel. -But this voyage can scarcely be regarded as an attempt to -approach the Pole on that course; for Koldewey’s instructions -were, “to explore the eastern coast of Greenland -northwards; and, if he found success in that direction impossible, -to make for the mysterious Island of Gilles on the -east of Spitzbergen.”</p> - -<p>Scoresby in 1806 had made thus far the most northerly -voyage in a ship on Hudson’s route, but in 1868 a Swedish -expedition attained higher latitudes than had ever or have -ever been reached by a ship in that direction. The steamship -<i>Sofia</i>, strongly built of Swedish iron, and originally -intended for winter voyages in the Baltic, was selected for -the voyage. Owing to a number of unfortunate delays, it -was not until September, 1868, that the <i>Sofia</i> reached the -most northerly part of her journey, attaining a point nearly -fifteen miles further north than Hudson had reached. To -the north broken ice was still found, but it was so closely -packed that not even a boat could pass through. Two<span class="pagenum"><a id="Page_161">161</a></span> -months earlier in the season the voyagers might have waited -for a change of wind and the breaking up of the ice; but -in the middle of September this would have been very -dangerous. The temperature was already sixteen degrees -below the freezing-point, and there was every prospect that -in a few weeks, or even days, the seas over which they had -reached their present position would be icebound. They -turned back from that advanced position; but, with courage -worthy of the old Vikings, they made another attack a -fortnight later. They were foiled again, as was to be expected, -for by this time the sun was already on the wintry -side of the equator. They had, indeed, a narrow escape -from destruction. “An ice-block with which they came -into collision opened a large leak in the ship’s side, and -when, after great exertions, they reached the land, the water -already stood two feet over the cabin floor.”<a id="FNanchor_21" href="#Footnote_21" class="fnanchor">21</a></p> - -<p>On the western side of the North Atlantic Channel—so -to term the part lying between Greenland and Spitzbergen—the -nearest approach towards the Pole was made -by the Dutch in 1670, nearly all the more recent attempts -to reach high northern latitudes in this direction having -hitherto ended in failure more or less complete.</p> - -<p>We have already seen that Captain Koldewey was -charged to explore the eastern coast of Greenland in the -<i>Germania</i> in 1868. In 1869 the <i>Germania</i> was again -despatched under his command from Bremerhaven, in -company with the <i>Hansa</i>, a sailing vessel. Lieutenant -Payer and other Austrian <i xml:lang="fr" lang="fr">savants</i> accompanied Captain -Koldewey. The attack was again made along the eastern -shores of Greenland. As far as the 74th degree the two -vessels kept company; but at this stage it happened unfortunately -that a signal from the <i>Germania</i> was misinterpreted,<span class="pagenum"><a id="Page_162">162</a></span> -and the <i>Hansa</i> left her. Soon after, the <i>Hansa</i> was crushed -by masses of drifting ice, and her crew and passengers -took refuge on an immense ice-floe seven miles in circumference. -Here they built a hut, which was in its turn -crushed. Winds and currents carried their icy home about, -and at length broke it up. Fortunately they had saved -their boats, and were able to reach Friedrichsthal, a missionary -station in the south of Greenland, whence they were -conveyed to Copenhagen in September, 1870. Returning -to the <i>Germania</i>, we find that she had a less unfortunate -experience. She entered the labyrinth of sinuous fjords, -separated by lofty promontories, and girt round by gigantic -glaciers, which characterize the eastern coast of Greenland -to the north of Scoresby Sound. In August the channels -by which she had entered were closed, and the <i>Germania</i> -was imprisoned. So soon as the ice would bear them, -Koldewey and his companions made sledging excursions -to various points around their ship. But in November -the darkness of the polar winter settled down upon them, -and these excursions ceased. The polar winter of 1869–70 -was “characterized by a series of violent northerly tempests, -one of which continued more than 100 hours, with a -velocity (measured by the anemometer) of no less than -sixty miles an hour”—a velocity often surpassed, indeed, -but which must have caused intense suffering to all who -left the shelter of the ship; for it is to be remembered -that the air which thus swept along at the rate of a mile -a minute was the bitter air of the Arctic regions. The -thermometer did not, however, descend lower than 26° -below zero, or 58° below the freezing-point—a cold often -surpassed in parts of the United States. I have myself -experienced a cold of more than 30° below zero, at -Niagara. “With proper precautions as regards shelter and -clothing,” proceeds the narrative, “even extreme cold need -not cause great suffering to those who winter in such -regions. One of the worst things to be endured is the -physical and moral weariness of being cut off from external<span class="pagenum"><a id="Page_163">163</a></span> -observations during the long night of some ninety -days, relieved only by the strange Northern Lights. The -ice accumulates all round with pressure, and assumes peculiar -and fantastic forms, emitting ever and anon ominous -noises. Fortunately, the <i>Germania</i> lay well sheltered in a -harbour opening southwards, and, being protected by a -rampart of hills on the north, was able to resist the shock -of the elements. The sun appearing once more about the -beginning of February, the scientific work of exploration -began.... The pioneers of the <i>Germania</i> advanced -as far as the 77th degree of latitude, in longitude 18° 50´ -west from Greenwich. There was no sign of an open sea -towards the Pole. <em>Had it not been for want of provisions, -the party could have prolonged their sledge journey indefinitely.</em> -The bank of ice, without remarkable protuberances, extends -to about two leagues from the shore, which from -this extreme point seems to trend towards the north-west, -where the view was bounded by lofty mountains.” As the -expedition was only equipped for one winter, it returned -to Europe in September, 1870, without having crossed the -78th parallel of north latitude.</p> - -<p>Captain Koldewey was convinced, by the results of his -exploration, that there is no continuous channel northwards -along the eastern coast of Greenland. It does not seem to -me that his expedition proved this beyond all possibility of -question. Still, it seems clear that the eastern side of the -North Atlantic is less suited than the western for the attempt -to reach the North Pole. The prevailing ocean-currents are -southerly on that side, just as they are northerly on the -western side. The cold also is greater, the lines of equal -temperature lying almost exactly in the direction of the -channel itself—that is, nearly north and south—and the cold -increasing athwart that direction, towards the west. The -nearer to Greenland the greater is the cold.<a id="FNanchor_22" href="#Footnote_22" class="fnanchor">22</a></p> - -<p><span class="pagenum"><a id="Page_164">164</a></span> -The next route to be considered in order of time would -be the American route; but I prefer to leave this to the -last, as the latest results relate to that route. I take next, -therefore, a route which some regard as the most promising -of all—that, namely, which passes between Spitzbergen and -the Scandinavian peninsula.</p> - -<p>It will be remembered that Lieutenant Payer, of the -Austrian navy, had accompanied Captain Koldewey’s first -expedition. When driven back from the attempt to advance -along the eastern shores of Greenland, that commander -crossed over to Spitzbergen, and tried to find the Land of -Gilles. He also accompanied Koldewey’s later expedition, -and shared his belief that there is no continuous channel -northwards on the western side of the North Atlantic channel. -Believing still, however, with Dr. Petermann, the geographer, -that there is an open Polar sea beyond the ice-barrier, Payer -set out in 1871, in company with Weyprecht, towards the -Land of Gilles. They did not find this mysterious land, but -succeeded in passing 150 miles further north, after rounding -the south-eastern shores of Spitzbergen, than any Arctic -voyagers who had before penetrated into the region lying -between Spitzbergen and Novaia Zemlia. Here they found, -beyond the 76th parallel, and between 42° and 60° east -longitude, an open sea, and a temperature of between 5° -and 7° above the freezing-point. Unfortunately, they had -not enough provisions with them to be able safely to travel -further north, and were thus compelled to return. The -season seems to have been an unusually open one; and it -is much to be regretted that the expedition was not better<span class="pagenum"><a id="Page_165">165</a></span> -supplied with provisions—a defect which appears to be -not uncommon with German expeditions.</p> - -<p>Soon after their return, Payer and Weyprecht began to -prepare for a new expedition; and this time their preparations -were thorough, and adapted for a long stay in Arctic -regions. “The chief aim of this expedition,” says the <cite xml:lang="fr" lang="fr">Revue -des Deux Mondes</cite>, in an interesting account of recent Polar -researches, “was to investigate the unknown regions of the -Polar seas to the north of Siberia, and to try to reach -Behring’s Straits by this route.” It was only if after two -winters and three summers they failed to double the extreme -promontory of Asia, that they were to direct their course -towards the Pole. The voyagers, numbering twenty-four -persons, left the Norwegian port of Tromsoë, in the steamer -<i>Tegethoff</i>, on July 14, 1872. Count Wilczek followed shortly -after in a yacht, which was to convey coals and provisions to -an eastern point of the Arctic Ocean, for the benefit of the -<i>Tegethoff</i>. At a point between Novaia Zemlia and the -mouth of the Petschora, the yacht lost sight of the steamer, -and nothing was heard of the latter for twenty-five months. -General anxiety was felt for the fate of the expedition, and -various efforts were made by Austria, England, and Russia -to obtain news of it. In September, 1874, the voyagers -suddenly turned up at another port, and soon after entered -Vienna amid great enthusiasm. Their story was a strange -one.</p> - -<p>It appears that when the <i>Tegethoff</i> was lost sight of -(August 21, 1872), she had been surrounded by vast masses -of ice, which crushed her hull. For nearly half a year the -deadly embrace of the ice continued; and when at length -pressure ceased, the ship remained fixed in the ice, several -miles from open water. During the whole summer the -voyagers tried to release their ship, but in vain. They had -not, however, remained motionless all this time. The yacht -had lost sight of them at a spot between Novaia Zemlia and -Malaia Zemlia (in North Russia) in about 71° north latitude, -and they were imprisoned not far north of this spot. But<span class="pagenum"><a id="Page_166">166</a></span> -the ice-field was driven hither and thither by the winds, -until they found themselves, on the last day of August, 1873, -only 6´ or about seven miles south of the 80th parallel of latitude. -Only fourteen miles from them, on the north, they saw -“a mass of mountainous land, with numerous glaciers.” They -could not reach it until the end of October, however, and then -they had to house themselves in preparation for the long -winter night. This land they called Francis Joseph Land. -It lies north of Novaia Zemlia, and on the Polar side of the -80th parallel of latitude. The winter was stormy and bitterly -cold, the thermometer descending on one occasion to 72° -below zero—very nearly as low as during the greatest cold -experienced by Nares’s party. In February, 1874, “the -sun having reappeared, Lieutenant Payer began to prepare -sledge excursions to ascertain the configuration of the land.... -In the second excursion the voyagers entered Austria -Sound, which bounds Francis Joseph Island on the east and -north, and found themselves, after emerging from it, in the -midst of a large basin, surrounded by several large islands. -The extreme northern point reached by the expedition was -a cape on one of these islands, which they named Prince -Rodolph’s Land, calling the point Cape Fligely. It lies -a little beyond the 81st parallel. They saw land further -north beyond the 83rd degree of latitude, and named it -Petermann’s Land. The archipelago thus discovered is -comparable in extent to that of which Spitzbergen is the -chief island.” The voyagers were compelled now to return, -as the firm ice did not extend further north. They had -a long, difficult, and dangerous journey southwards—sometimes -on open water, in small boats, sometimes on ice, with -sledges—impeded part of the time by contrary winds, and -with starvation staring them in the face during the last -fortnight of their journey. Fortunately, they reached Novaia -Zemlia before their provisions quite failed them, and were -thence conveyed to Wardhoë by a Russian trading ship.</p> - -<p>We have now only to consider the attempts which have -been made to approach the North Pole by the American<span class="pagenum"><a id="Page_167">167</a></span> -route. For, though Collinson in 1850 reached high latitudes -to the north of Behring’s Straits, while Wrangel and -other Russian voyagers have attempted to travel northwards -across the ice which bounds the northern shores of Siberia, -it can hardly be said that either route has been followed -with the definite purpose of reaching the North Pole. I -shall presently, however, have occasion to consider the probable -value of the Behring’s Straits route, which about twelve -years ago was advocated by the Frenchman Lambert.</p> - -<p>Dr. Kane’s expedition in 1853–55 was one of those sent -out in search of Sir John Franklin. It was fitted out at -the expense of the United States Government, and the route -selected was that along Smith’s Sound, the northerly prolongation -of Baffin’s Bay. Kane wintered in 1853 and -1854 in Van Reusselaer’s Inlet, on the western coast of -Greenland, in latitude 78° 43´ north. Leaving his ship, the -<i>Advance</i>, he made a boat-journey to Upernavik, 6° further -south. He next traced Kennedy Channel, the northerly -prolongation of Smith’s Sound, reaching latitude 81° 22´ -north. He named heights visible yet further to the north, -Parry Mountains; and at the time—that is, twenty-two years -ago—the land so named was the highest northerly land yet -seen. Hayes, who had accompanied Kane in this voyage, -succeeded in reaching a still higher latitude in sledges -drawn by Esquimaux dogs. Both Kane and Hayes agreed -in announcing that where the shores of Greenland trend -off eastwards from Kennedy Channel, there is an open -sea, “rolling,” as Captain Maury magniloquently says, “with -the swell of a boundless ocean.” It was in particular -noticed that the tides ebbed and flowed in this sea. On -this circumstance Captain Maury based his conclusion that -there is an open sea to the north of Greenland. After -showing that the tidal wave could not well have travelled -along the narrow and icebound straits between Baffin’s Bay -and the region reached by Kane and Hayes, Maury says: -“Those tides must have been born in that cold sea, having -their cradle about the North Pole.” The context shows,<span class="pagenum"><a id="Page_168">168</a></span> -however, that he really intended to signify that the waves -were formed in seas around the North Pole, and thence -reached the place where they were seen; so that, as birth -usually precedes cradling, Maury would more correctly have -said that these tides are cradled in that cold sea, having their -birth about the North Pole.</p> - -<p>The observations of Kane and Hayes afford no reason, -however, for supposing that there is open water around -the North Pole. They have been rendered somewhat doubtful, -be it remarked in passing, by the results of Captain -Nares’s expedition; and it has been proved beyond -all question that there is not an open sea directly communicating -with the place where Kane and Hayes observed -tidal changes. But, apart from direct evidence of this kind, -two serious errors affect Maury’s reasoning, as I pointed -out eleven years since. In the first place, a tidal wave -would be propagated quite freely along an ice-covered -sea, no matter how thick the ice might be, so long as the -sea was not absolutely icebound. Even if the latter condition -could exist for a time, the tidal wave would burst -the icy fetters that bound the sea, unless the sea were frozen -to the very bottom; which, of course, can never happen -with any sea properly so called. It must be remembered -that, even in the coldest winter of the coldest Polar regions, -ice of only a moderate thickness can form in open sea in -a single day; but the tidal wave does not allow ice to form -for a single hour in such sort as to bind the great ice-fields -and the shore-ice into one mighty mass. At low tide, for a -very short time, ice may form in the spaces between the -shore-ice and the floating ice, and again between the various -masses of floating ice, small or large (up to many square -miles in extent); but as the tidal wave returns it breaks -through these bonds as easily as the Jewish Hercules burst -the withes with which the Philistines had bound his mighty -limbs. It is probable that if solid ice as thick as the -thickest which Nares’s party found floating in the Palæocrystic -Sea—ice 200 feet thick—reached from shore to shore<span class="pagenum"><a id="Page_169">169</a></span> -of the North Atlantic channel, the tidal wave would burst -the barrier as easily as a rivulet rising but a few inches bursts -the thin coating which has formed over it on the first cold -night of autumn. But no such massive barriers have to be -broken through, for the tidal wave never gives the ice an -hour’s rest Maury reasons that “the tidal wave from the -Atlantic can no more pass under the icy barrier to be propagated -in the seas beyond, than the vibrations of a musical -string can pass with its notes a fret on which the musician -has placed his finger.” But the circumstances are totally -different. The ice shares the motion of the tidal wave, -which has not to pass under the ice, but to lift it. This, -of course, it does quite as readily as though there were -no ice, but only the same weight of water. The mere -weight of the ice counts simply for nothing. The tidal wave -would rise as easily in the British Channel if a million Great -Easterns were floating there as if there was not even a -cock-boat; and the weight of ice, no matter how thick or -extensive, would be similarly ineffective to restrain the great -wave which the sun and moon send coursing twice a day -athwart our oceans. Maury’s other mistake was even more -important so far as this question of an open sea is concerned. -“No one,” as I wrote in 1867, “who is familiar -with the astronomical doctrine of the tides, can believe for -a moment that tides could be generated in a land-locked -ocean, so limited in extent as the North Polar sea (assuming -its existence) must necessarily be.” To raise a tidal wave -the sun and moon require not merely an ocean of wide -extent to act upon, but an ocean so placed that there is -a great diversity in their pull on various parts of it; for it -is the difference between the pull exerted on various parts, -and not the pull itself, which creates the tidal wave. Now -the Polar sea has not the required extent, and is not in -the proper position, for this diversity of pull to exist in -sufficient degree to produce a tidal wave which could be -recognized. It is certain, in fact, that, whether there is -open water or not near the Pole, the tides observed by<span class="pagenum"><a id="Page_170">170</a></span> -Kane and Hayes must have come from the Atlantic, and -most probably by the North Atlantic channel.</p> - -<p>Captain Hall’s expedition in the <i>Polaris</i> (really under -the command of Buddington), in 1871–72, will be probably -in the recollection of most of my readers. Leaving Newfoundland -on June 29, 1871, it sailed up Smith’s Sound, -and by the end of August had reached the 80th parallel. -Thence it proceeded up Kennedy Channel, and penetrated -into Robeson Channel, the northerly prolongation -of Kennedy Channel, and only 13 miles wide. Captain -Hall followed this passage as far as 82° 16´ north latitude, -reaching his extreme northerly point on September 3. -From it he saw “a vast expanse of open sea, which he -called Lincoln Sea, and beyond that another ocean or gulf; -while on the west there appeared, as far as the eye could -reach, the contours of coast. This region he called Grant -Land.” So far as appears, there was no reason at that time -why the expedition should not have gone still further north, -the season apparently having been exceptionally open. -But the naval commander of the expedition, Captain Buddington, -does not seem to have had his heart in the work, -and, to the disappointment of Hall, the <i>Polaris</i> returned -to winter in Robeson Channel, a little beyond the 81st -degree. In the same month, September, 1871, Captain -Hall died, under circumstances which suggested to many -of the crew and officers the suspicion that he had been -poisoned.<a id="FNanchor_23" href="#Footnote_23" class="fnanchor">23</a> In the spring of 1870 the <i>Polaris</i> resumed -her course homewards. They were greatly impeded by the -ice. A party which got separated from those on board -were unfortunately unable to regain the ship, and remained -on an ice-field for 240 days, suffering fearfully. The ice-field, -like that on which the crew of the <i>Hansa</i> had to -take up their abode, drifted southwards, and was gradually -diminishing, when fortunately a passing steamer observed<span class="pagenum"><a id="Page_171">171</a></span> -the prisoners (April 30, 1872) and rescued them. The -<i>Polaris</i> herself was so injured by the ice that her crew had -to leave her, wintering on Lyttelton Island. They left this -spot in the early summer of 1872, in two boats, and were -eventually picked up by a Scotch whaler.</p> - -<p>Captain Nares’s expedition followed Hall’s route. I -do not propose to enter here into any of the details of the -voyage, with which my readers are no doubt familiar. -The general history of the expedition must be sketched, -however, in order to bring it duly into its place here. -The <i>Alert</i> and <i>Discovery</i> sailed under Captains Nares and -Stephenson, in May, 1875. Their struggle with the ice -did not fairly commence until they were nearing the 79th -parallel, where Baffin’s Bay merges into Smith’s Sound. -Thence, through Smith’s Sound, Kennedy Channel, and -Robeson Channel, they had a constant and sometimes -almost desperate struggle with the ice, until they had -reached the north end of Robeson Channel. Here the -<i>Discovery</i> took up her winter quarters, in north latitude -81° 44´, a few miles north of Captain Hall’s wintering-place, -but on the opposite (or westerly) side of Robeson Channel. -The <i>Alert</i> still struggled northwards, rounding the north-east -point of Grant Land, and there finding, not, as was -expected, a continuous coast-line on the west, but a vast -icebound sea. No harbour could be found, and the ship -was secured on the inside of a barrier of grounded ice, -in latitude 82° 31´, in the most northerly wintering-place -ever yet occupied by man. The ice met with on this sea -is described as “of most unusual age and thickness, resembling -in a marked degree, both in appearance and -formation, low floating icebergs rather than ordinary salt-water -ice. Whereas ordinary ice is from 2 feet to 10 feet -in thickness, that in this Polar sea has gradually increased -in age and thickness until it measures from 80 feet to 120 -feet, floating with its surface at the lower part 15 feet above -the water-line. In some places the ice reaches a thickness -of from 150 to 200 feet, and the general impression among<span class="pagenum"><a id="Page_172">172</a></span> -the officers of the expedition seems to have been that the -ice of this Palæocrystic Sea is the accumulation of many -years, if not of centuries; “that the sea is never free of -it and never open; and that progress to the Pole through -it or over it is impossible with our present resources.”</p> - -<p>The winter which followed was the bitterest ever known -by man. For 142 days the sun was not seen; the mercury -was frozen during nearly nine weeks. On one occasion the -thermometer showed 104° below the freezing-point, and -during one terrible fortnight the mean temperature was 91° -below freezing!</p> - -<p>As soon as the sun reappeared sledge-exploration began, -each ship being left with only half-a-dozen men and officers -on board. Expeditions were sent east and west, one to -explore the northern coast of Greenland, the other to -explore the coast of Grant Land. Captain Stephenson -crossed over from the <i>Discovery’s</i> wintering-place to Polaris -Bay, and there placed over Hall’s grave a tablet, prepared -in England, bearing the following inscription: “Sacred -to the memory of Captain C. F. Hall, of U.S. <i>Polaris</i>, -who sacrificed his life in the advancement of science, on -November 8, 1871. This tablet has been erected by the -British Polar Expedition of 1875, who, following in his -footsteps, have profited by his experience”—a graceful -acknowledgment (which might, however, have been better -expressed). The party which travelled westwards traced -the shores of Grant Land as far as west longitude 86° 30´, -the most northerly cape being in latitude 83° 7´, and longitude -70° 30´ west. This cape they named Cape Columbia.</p> - -<p>The coast of Greenland was explored as far east as -longitude 50° 40´ (west), land being seen as far as 82° 54´ -north, longitude 48° 33´ west. Lastly, a party under Commander -Markham and Lieutenant Parr pushed northwards. -They were absent ten weeks, but had not travelled so far -north in the time as was expected, having encountered -great difficulties. On May 12, 1876, they reached their -most northerly point, planting the British flag in latitude<span class="pagenum"><a id="Page_173">173</a></span> -83° 20´ 26´´ north. “Owing to the extraordinary nature of -the pressed-up ice, a roadway had to be formed by pickaxes -for nearly half the distance travelled, before any advance -could be safely made, even with light loads; this rendered -it always necessary to drag the sledge-loads forward by -instalments, and therefore to journey over the same road -several times. The advance was consequently very slow, -and only averaged about a mile and a quarter daily—much -the same rate as was attained by Sir Edward Parry during -the summer of 1827. The greatest journey made in any one -day amounted only to two miles and three quarters. Although -the distance made good was only 73 miles from the ship, 276 -miles were travelled over to accomplish it.” It is justly -remarked, in the narrative from which I have made this -extract, that no body of men could have surpassed in praiseworthy -perseverance this gallant party, whose arduous -struggle over the roughest and most monotonous road -imaginable, may fairly be regarded as surpassing all former -exploits of the kind. (The narrator says that it has -“eclipsed” all former ones, which can scarcely be intended -to be taken <i xml:lang="fr" lang="fr">au pied de la lettre</i>.) The expedition reached -the highest latitude ever yet attained under any conditions, -carried a ship to higher latitudes than any ship had before -reached, and wintered in higher latitudes than had -ever before been dwelt in during the darkness of a Polar -winter. They explored the most northerly coast-line yet -traversed, and this both on the east and west of their route -northwards. They have ascertained the limits of human -habitation upon this earth, and have even passed beyond the -regions which animals occupy, though nearly to the most -northerly limit of the voyage they found signs of the -occasional visits of warm-blooded animals. Last, but not -least, they have demonstrated, as it appears to me (though -possibly Americans will adopt a different opinion), that by -whatever route the Pole is to be reached, it is not by that -which I have here called the American route, at least with -the present means of transit over icebound seas. The<span class="pagenum"><a id="Page_174">174</a></span> -country may well be satisfied with such results (apart -altogether from the scientific observations, which are the best -fruits of the expedition), even though the Pole has not yet -been reached.</p> - -<p>Must we conclude, however, that the North Pole is -really inaccessible? It appears to me that the annals of -Arctic research justify no such conclusion. The attempt -which has just been made, although supposed at the outset -to have been directed along the most promising of all the -routes heretofore tried, turned out to be one of the most -difficult and dangerous. Had there been land extending -northwards (as Sherard Osborn and others opined), on the -western side of the sea into which Robeson Channel opens, -a successful advance might have been made along its shore -by sledging. M’Clintock, in 1853, travelled 1220 miles in -105 days; Richards 1012 miles in 102 days; Mecham -1203 miles; Richards and Osborn 1093 miles; Hamilton -1150 miles with a dog-sledge and one man. In 1854 Mecham -travelled 1157 miles in only 70 days; Young travelled -1150 miles and M’Clintock 1330 miles. But these journeys -were made either over land or over unmoving ice close to a -shore-line. Over an icebound sea journeys of the kind are -quite impracticable. But the conditions, while not more -favourable in respect of the existence of land, were in other -respects altogether less favourable along the American route -than along any of the others I have considered in this brief -sketch of the attempts hitherto made to reach the Pole.</p> - -<p>The recent expedition wintered as near as possible to the -region of maximum winter cold in the western hemisphere, -and pushed their journey northwards athwart the region of -maximum summer cold. Along the course pursued by -Parry’s route the cold is far less intense, in corresponding -latitudes, than along the American route; and cold is the -real enemy which bars the way towards the Pole. All the -difficulties and dangers of the journey either have their -origin (as directly as the ice itself) in the bitter Arctic cold, -or are rendered effective and intensified by the cold. The<span class="pagenum"><a id="Page_175">175</a></span> -course to be pursued, therefore, is that indicated by the -temperature. Where the July isotherms, or lines of equal -summer heat, run northwards, a weak place is indicated in -the Arctic barrier; where they trend southwards, that barrier -is strongest. Now there are two longitudes in which the -July Arctic isotherms run far northward of their average -latitude. One passes through the Parry Islands, and -indicates the sea north-east of Behring’s Straits as a suitable -region for attack; the other passes through Spitzbergen, and -indicates the course along which Sir E. Parry’s attack was -made. The latter is slightly the more promising line of the -two, so far as temperature is concerned, the isotherm of 36° -Fahrenheit (in July) running here as far north as the 77th -parallel, whereas its highest northerly range in the longitude -of the Parry Islands is but about 76°. The difference, however, -is neither great nor altogether certain; and the fact -that Parry found the ice drifting southwards, suggests the -possibility that that <em>may</em> be the usual course of oceanic -currents in that region. North of the Parry Islands the drift -may be northwardly, like that which Payer and Weyprecht -experienced to the north of Novaia Zemlia.</p> - -<p>There is one great attraction for men of science in the -route by the Parry Islands. The magnetic pole has almost -certainly travelled into that region. Sir J. Ross found it, -indeed, to be near Boothia Gulf, far to the east of the -Parry Islands, in 1837. But the variations of the needle all -over the world since then, indicate unmistakably that the -magnetic poles have been travelling round towards the west, -and at such a rate that the northern magnetic pole has probably -nearly reached by this time the longitude of Behring’s -Straits. The determination of the exact present position of -the Pole would be a much more important achievement, so -far as science is concerned, than a voyage to the pole of -rotation.</p> - -<p>There is one point which suggests itself very forcibly -in reading the account of the sledging expedition from the -<i>Alert</i> towards the north. In his official report, Captain<span class="pagenum"><a id="Page_176">176</a></span> -Nares says that “half of each day was spent in dragging -the sledges in that painful fashion—face toward the boat—in -which the sailors drag a boat from the sea on to the -sand;” and again he speaks of the “toilsome dragging of -the sledges over ice-ridges which resembled a stormy sea -suddenly frozen.” In doing this “276 miles were toiled -over in travelling only 73 miles.” Is it altogether clear -that the sledges were worth the trouble? One usually regards -a sledge as intended to carry travellers and their -provisions, etc., over ice and snow, and as useful when so -employed; but when the travellers have to take along the -sledge, going four times as far and working ten times as -hard as if they were without it, the question suggests itself -whether all necessary shelter, provisions, and utensils might -not have been much more readily conveyed by using a -much smaller and lighter sledge, and by distributing a large -part of the luggage among the members of the expedition. -The parts of a small hut could, with a little ingenuity, be -so constructed as to admit of being used as levers, crowbars, -carrying-poles, and so forth, and a large portion of the -luggage absolutely necessary for the expedition could be -carried by their help; while a small, light sledge for the -rest could be helped along and occasionally lifted bodily -over obstructions by levers and beams forming part of the -very material which by the usual arrangement forms part -of the load. I am not suggesting, be it noticed, that by -any devices of this sort a journey over the rough ice of -Arctic regions could be made easy. But it does seem to me -that if a party could go back and forth over 276 miles, -pickaxing a way for a sledge, and eventually dragging it -along over the path thus pioneered for it, and making only -an average of 1¼ mile of real progress per day, or 73 miles -in all, the same men could with less labour (though still, -doubtless, with great toil and trouble) make six or seven -miles a day by reducing their <i xml:lang="la" lang="la">impedimenta</i> to what could -be carried directly along with them. Whether use might not -be made of the lifting power of buoyant gas, is a question<span class="pagenum"><a id="Page_177">177</a></span> -which only experienced aëronauts and Arctic voyagers could -answer. I believe that the employment of imprisoned -balloon-power for many purposes, especially in time of war, -has received as yet much less attention than it deserves. -Of course I am aware that in Arctic regions many difficulties -would present themselves; and the idea of ordinary -ballooning over the Arctic ice-fields may be regarded as -altogether wild in the present condition of the science of -aëronautics. But the use of balloon-power as an auxiliary, -however impracticable at present, is by no means to be -despaired of as science advances.</p> - -<p>After all, however, the advance upon the Pole itself, -however interesting to the general public, is far less important -to science than other objects which Arctic travellers -have had in view. The inquiry into the phenomena of -terrestrial magnetism within the Arctic regions; the investigation -of oceanic movements there; of the laws according -to which low temperatures are related to latitude and -geographical conditions; the study of aerial phenomena; -of the limits of plant life and animal life; the examination -of the mysterious phenomena of the Aurora Borealis—these -and many other interesting subjects of investigation have -been as yet but incompletely dealt with. In the Polar -regions, as Maury well remarked, “the icebergs are framed -and glaciers launched; there the tides have their cradle, -the whales their nursery; there the winds complete their -circuit, and the currents of the sea their round, in the wonderful -system of oceanic circulation; there the Aurora is -lighted up, and the trembling needle brought to rest; and -there, too, in the mazes of that mystic circle, terrestrial -forces of occult power and of vast influence upon the well-being -of man are continually at work. It is a circle of -mysteries; and the desire to enter it, to explore its untrodden -wastes and secret chambers, and to study its -physical aspects, has grown into a longing. Noble daring -has made Arctic ice and snow-clad seas classic ground.”</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_178">178</a></span></p> - -<div class="chapter"> -<h2><a id="A_MIGHTY_SEA-WAVE"></a><i>A MIGHTY SEA-WAVE.</i></h2> -</div> - -<p class="in0">On May 10th, 1876, a tremendous wave swept the Pacific -Ocean from Peru northwards, westwards, and southwards, -travelling at a rate many times greater than that of the -swiftest express train. For reasons best known to themselves, -writers in the newspapers have by almost common -consent called this phenomenon a tidal-wave. But the -tides had nothing to do with it. Unquestionably the -wave resulted from the upheaval of the bed of the ocean -in some part of that angle of the Pacific Ocean which is -bounded by the shores of Peru and Chili. This region -has long been celebrated for tremendous submarine and -subterranean upheavals. The opinions of geologists and -geographers have been divided as to the real origin of the -disturbances by which at one time the land, at another -time the sea, and at yet other times (oftener, in fact, than -either of the others) both land and sea have been shaken -as by some mighty imprisoned giant, struggling, like -Prometheus, to cast from his limbs the mountain masses -which hold them down. Some consider that the seat of -the Vulcanian forces lies deep below that part of the chain -of the Andes which lies at the apex of the angle just -mentioned, and that the direction of their action varies -according to the varying conditions under which the imprisoned -gases find vent. Others consider that there are -two if not several seats of subterranean activity. Yet -others suppose that the real seat of disturbance lies beneath<span class="pagenum"><a id="Page_179">179</a></span> -the ocean itself, a view which seems to find support in -several phenomena of recent Peruvian earthquakes.</p> - -<p>Although we have not full information concerning the -great wave which in May, 1876, swept across the Pacific, -and northwards and southwards along the shores of the -two Americas, it may be interesting to consider some of -the more striking features of this great disturbance of the -so-called peaceful ocean, and to compare them with those -which have characterized former disturbances of a similar -kind. We may thus, perhaps, find some evidence by which -an opinion may be formed as to the real seat of subterranean -activity in this region.</p> - -<p>At the outset it may be necessary to explain why I -have asserted somewhat confidently that the tides have -nothing whatever to do with this great oceanic wave. It -is of course well known to every reader that the highest -or spring tides occur always two or three days after new -moon and after full moon, the lowest (or rather the tides -having least range above and below the mean level) occurring -two or three days after the first and third quarters of -the lunar month. The sun and moon combine, indeed, -to sway the ocean most strongly at full and new, while they -pull contrariwise at the first and third quarters; but the -full effect of their combined effort is only felt a few days -later than when it is made, while the full effect of their -opposition to each other, in diminishing the range of the -oceanic oscillation, is also only felt after two or three -days. Thus in May, 1876, the tidal wave had its greatest -range on or about May 16, new moon occurring at half-past -five on the morning of May 13; and the tidal wave -had its least range on or about May 8, the moon passing -her third quarter a little after eleven on the morning of -May 4. Accordingly the disturbance which affected the -waters of the Pacific so mightily on May 10, occurred two -days after the lowest or neap tides, and five days before -the highest or spring tides. Manifestly that was not a time -when a tidal wave of exceptional height could be expected,<span class="pagenum"><a id="Page_180">180</a></span> -or, indeed, could possibly occur. Such a wave as actually -disturbed the Pacific on that day could not in any case -have been produced by tidal action, even though the winds -had assisted to their utmost, and all the circumstances -which help to make high tides had combined—as the -greatest proximity of moon to earth, the conjunction of -moon and sun near the celestial equator, and (of course) -the exact coincidence of the time of the tidal disturbance -with that when the combined pull of the sun and moon is -strongest. As, instead, the sun was nearly eighteen degrees -from the equator, the moon more than nine, and as the -moon was a full week’s motion from the part of her path -where she is nearest to the earth, while, as we have seen, -only two days had passed from the time of absolutely lowest -tides, it will be seen how utterly unable the tidal-wave -must have been on the day of the great disturbance to produce -the effects presently to be described.</p> - -<p>It may seem strange, in dealing with the case of a wave -which apparently had its origin in or near Peru on May 9, -to consider the behaviour of a volcano, distant 5000 miles -from this region, a week before the disturbance took place. -But although the coincidence may possibly have been -accidental, yet in endeavouring to ascertain the true seat of -disturbance we must overlook no evidence, however seemingly -remote, which may throw light on that point; and -as the sea-wave generated by the disturbance reached very -quickly the distant region referred to, it is by no means -unlikely that the subterranean excitement which the disturbance -relieved may have manifested its effects beforehand -at the same remote volcanic region. Be this as it -may, it is certain that on May 1 the great crater of Kilauea, -in the island of Hawaii, became active, and on the 4th -severe shocks of earthquake were felt at the Volcano -House. At three in the afternoon a jet of lava was thrown -up to a height of about 100 feet, and afterwards some fifty -jets came into action. Subsequently jets of steam issued -along the line formed by a fissure four miles in length<span class="pagenum"><a id="Page_181">181</a></span> -down the mountain-side. The disturbance lessened considerably -on the 5th, and an observing party examined the -crater. They found that a rounded hill, 700 feet in height, -and 1400 feet in diameter, had been thrown up on the -plain which forms the floor of the crater. Fire and scoria -spouted up in various places.</p> - -<p>Before rejecting utterly the belief that the activity thus -exhibited in the Hawaii volcano had its origin in the same -subterrene or submarine region as the Peruvian earthquake, -we should remember that other regions scarcely less remote -have been regarded as forming part of the same Vulcanian -district. The violent earthquakes which occurred at New -Madrid, in Missouri, in 1812, took place at the same time -as the earthquake of Caraccas, the West Indian volcanoes -being simultaneously active; and earthquakes had been -felt in South Carolina for several months before the destruction -of Caraccas and La Guayra. Now we have abundant -evidence to show that the West Indian volcanoes are -connected with the Peruvian and Chilian regions of Vulcanian -energy, and the Chilian region is about as far from -New Madrid as Arica in Peru from the Sandwich Isles.</p> - -<p>It was not, however, until about half-past eight on the -evening of May 9 that the Peruvian earthquake began. A -severe shock, lasting from four to five minutes, was felt -along the entire southern coast, even reaching Antofagasta. -The shock was so severe that it was impossible, in many -places, to stand upright. It was succeeded by several others -of less intensity.</p> - -<p>While the land was thus disturbed, the sea was observed -to be gradually receding, a movement which former experiences -have taught the Peruvians to regard with even -more terror than the disturbance of the earth itself. The -waters which had thus withdrawn, as if concentrating their -energies to leap more fiercely on their prey, presently -returned in a mighty wave, which swept past Callao, travelling -southwards with fearful velocity, while in its train -followed wave after wave, until no less than eight had taken<span class="pagenum"><a id="Page_182">182</a></span> -their part in the work of destruction. At Mollendo the -railway was torn up by the sea for a distance of 300 feet. -A violent hurricane which set in afterwards from the south -prevented all vessels from approaching, and unroofed most -of the houses in the town. At Arica the people were busily -engaged in preparing temporary fortifications to repel a -threatened assault of the rebel ram <i>Huiscar</i>, at the moment -when the roar of the earthquake was heard. The shocks -here were very numerous, and caused immense damage in -the town, the people flying to the Morro for safety. The -sea was suddenly perceived to recede from the beach, and -a wave from ten feet to fifteen feet in height rolled in upon -the shore, carrying before it all that it met. Eight times was -this assault of the ocean repeated. The earthquake had -levelled to the ground a portion of the custom-house, the -railway station, the submarine cable office, the hotel, the -British Consulate, the steamship agency, and many private -dwellings. Owing to the early hour of the evening, and -the excitement attendant on the proposed attack of the -<i>Huiscar</i>, every one was out and stirring; but the only loss of -life which was reported was that of three little children who -were overtaken by the water. The progress of the wave -was only stopped at the foot of the hill on which the church -stands, which point is further inland than that reached in -August, 1868. Four miles of the embankment of the railway -were swept away like sand before the wind. Locomotives, -cars, and rails, were hurled about by the sea like -so many playthings, and left in a tumbled mass of rubbish.</p> - -<p>The account proceeds to say that the United States -steamer <i>Waters</i>, stranded by the bore of 1868, was lifted -up bodily by the wave at Arica, and floated two miles north -of her former position. The reference is no doubt to the -double-ender <i>Watertree</i>, not stranded by a bore (a term -utterly inapplicable to any kind of sea-wave at Arica, where -there is no large river), but carried in by the great wave -which followed the earthquake of August 13. The description -of the wave at Arica on that occasion should be<span class="pagenum"><a id="Page_183">183</a></span> -compared with that of the wave of May, 1876. About twenty -minutes after the first earth shock, the sea was seen to retire, -as if about to leave the shores wholly dry; but presently -its waters returned with tremendous force. A mighty wave, -whose length seemed immeasurable, was seen advancing -like a dark wall upon the unfortunate town, a large part -of which was overwhelmed by it. Two ships, the Peruvian -corvette <i>America</i>, and the American double-ender <i>Watertree</i>, -were carried nearly half a mile to the north of Arica, -beyond the railroad which runs to Tacna, and there left -stranded high and dry. As the English vice-consul at Arica -estimated the height of this enormous wave at fully fifty -feet, it would not seem that the account of the wave of May, -1876, has been exaggerated, for a much less height is, as -we have seen, attributed to it, though, as it carried the -<i>Watertree</i> still further inland, it must have been higher. -The small loss of life can be easily understood when we -consider that the earthquake was not followed instantly by -the sea-wave. Warned by the experience of the earthquake -of 1868, which most of them must have remembered, the -inhabitants sought safety on the higher grounds until the -great wave and its successors had flowed in. We read that -the damage done was greater than that caused by the previous -calamity, the new buildings erected since 1868 being -of a more costly and substantial class. Merchandise from -the custom-house and stores was carried by the water to a -point on the beach five miles distant.</p> - -<p>At Iquique, in 1868, the great wave was estimated at -fifty feet in height. We are told that it was black with -the mud and slime of the sea bottom. “Those who witnessed -its progress from the upper balconies of their houses, -and presently saw its black mass rushing close beneath their -feet, looked on their safety as a miracle. Many buildings -were, indeed, washed away, and in the low-lying parts of -the town there was a terrible loss of life.” In May, 1876, -the greatest mischief at Iquique would seem to have been -caused by the earthquake, not by the sea-wave, though<span class="pagenum"><a id="Page_184">184</a></span> -this also was destructive in its own way. “Iquique,” we -are told, “is in ruins. The movement was experienced -there at the same time and with the same force [as at -Arica]. Its duration was exactly four minutes and a third. -It proceeded from the south-east, exactly from the direction -of Ilaga.” The houses built of wood and cane tumbled down -at the first attacks, lamps were broken, and the burning oil -spread over and set fire to the ruins. Three companies of -firemen, German, Italian, and Peruvian, were instantly at -their posts, although it was difficult to maintain an upright -position, shock following shock with dreadful rapidity. -Nearly 400,000 quintals of nitrate in the stores at Iquique -and the adjacent ports of Molle and Pisagua were destroyed. -The British barque <i>Caprera</i> and a German barque sank, and -all the coasting craft and small boats in the harbour were -broken to pieces and drifted about in every direction.</p> - -<p>At Chanavaya, a small town at the guano-loading dépôt -known as Pabellon de Pica, only two houses were left -standing out of four hundred. Here the earthquake shock -was specially severe. In some places the earth opened in -crevices seventeen yards deep and the whole surface of the -ground was changed.</p> - -<p>At Punta de Eobos two vessels were lost, and fourteen -ships more or less damaged, by the wave. Antofagasta, Mexillones, -Tocopilla, and Cobigo, on the Bolivian coast, suffered -simultaneously from the earthquake and the sea-wave. The -sea completely swept the business portion of Antofagasta -during four hours. Here a singular phenomenon was -noticed. For some time the atmosphere was illuminated -with a ruddy glow. It was supposed that this light came -from the volcano of San Pedro de Atacama, a few leagues -inland from Antofagasta. A somewhat similar phenomenon -was noticed at Tacna during the earthquake of August, 1868. -About three hours after the earthquake an intensely brilliant -light made its appearance above the neighbouring mountains. -It lasted fully half an hour, and was ascribed to the eruption -of some as yet unknown volcano.</p> - -<p><span class="pagenum"><a id="Page_185">185</a></span> -As to the height of the great wave along this part of the -shore-line of South America, the accounts vary. According -to those which are best authenticated, it would seem as -though the wave exceeded considerably in height that which -flowed along the Peruvian, Bolivian, and Chilian shores in -August, 1868. At Huaniles the wave was estimated at sixty -feet in height, at Mexillones, where the wave, as it passed -southwards, ran into Mexillones Bay, it reached a height of -sixty-five feet. Two-thirds of the town were completely -obliterated, wharves, railway stations, distilleries, etc., all -swallowed up by the sea.</p> - -<p>The shipping along the Peruvian and Bolivian coast -suffered terribly. The list of vessels lost or badly injured at -Pabellon de Pica alone, reads like the list of a fleet.</p> - -<p>I have been particular in thus describing the effects -produced by the earthquake and sea-wave on the shores of -South America, in order that the reader may recognize in -the disturbance produced there the real origin of the great -wave which a few hours later reached the Sandwich Isles, -5000 miles away. Doubt has been entertained respecting -the possibility of a wave, other than the tidal-wave, being -transmitted right across the Pacific. Although in August, -1868, the course of the great wave which swept from -some region near Peru, not only across the Pacific, but in -all directions over the entire ocean, could be clearly traced, -there were some who considered the connection between the -oceanic phenomena and the Peruvian earthquake a mere -coincidence. It is on this account perhaps chiefly that the -evidence obtained in May, 1876, is most important. It is -interesting, indeed, as showing how tremendous was the disturbance -which the earth’s frame must then have undergone. -It would have been possible, however, had we no other -evidence, for some to have maintained that the wave which -came in upon the shores of the Sandwich Isles a few hours -after the earthquake and sea disturbance in South America -was in reality an entirely independent phenomenon. But -when we compare the events which happened in May, 1876,<span class="pagenum"><a id="Page_186">186</a></span> -with those of August, 1868, and perceive their exact similarity, -we can no longer reasonably entertain any doubt of the -really stupendous fact that <em>the throes of the earth in and near -Peru are of sufficient energy to send oceanic waves right across -the Pacific</em>,—waves, too, of such enormous height at starting, -that, after travelling with necessarily diminishing height the -whole way to Hawaii, they still rose and fell through thirty-six -feet The real significance of this amazing oceanic disturbance -is exemplified by the wave circles which spread around -the spot where a stone has fallen into a smooth lake. We -know how, as the circles widen, the height of the wave grows -less and less, until, at no great distance from the centre of -disturbance, the wave can no longer be discerned, so slight -is the slope of its advancing and following faces. How -tremendous, then, must have been the upheaval of the bed -of ocean by which wave-circles were sent across the Pacific, -retaining, after travelling 5000 miles from the centre of disturbance, -the height of a two-storied house! In 1868, indeed, -we know that the wave travelled very much further, reaching -the shores of Japan, of New Zealand, and of Australia, even -if it did not make its way through the East Indian Archipelago -to the Indian Ocean, as some observations seem to -show. Although no news has been received which would -justify us in believing that the wave of May, 1876, produced -corresponding effects at such great distances from the centre -of disturbance, it must be remembered that the dimensions -of the wave when it reached the Sandwich Isles fell far -short of those of the great wave of August 13–14, 1868.</p> - -<p>It will be well to make a direct comparison between the -waves of May, 1876, and August, 1868, in this respect, as -also with regard to the rate at which they would seem to have -traversed the distance between Peru and Hawaii. On this -last point, however, it must be noted that we cannot form an -exact opinion until we have ascertained the real region of -Vulcanian disturbance on each occasion. It is possible that -a careful comparison of times, and of the direction in which -the wave front advanced upon different shores, might serve<span class="pagenum"><a id="Page_187">187</a></span> -to show where this region lay. I should not be greatly -surprised to learn that it was far from the continent of South -America.</p> - -<p>The great wave reached the Sandwich Isles between four -and five on the morning of May 10, corresponding to about -five hours later of Peruvian time. An oscillation only was -first observed at Hilo, on the east coast of the great southern -island of Hawaii, the wave itself not reaching the village till -about a quarter before five. The greatest difference between -the crest and trough of the wave was found to be thirty-six -feet here; but at the opposite side of the island, in Kealakekua -Bay (where Captain Cook was killed), amounted only -to thirty feet. In other places the difference was much less, -being in some only three feet, a circumstance doubtless due -to interference, waves which have reached the same spot -along different courses chancing so to arrive that the crest of -one corresponded with the trough of the other, so that the -resulting wave was only the difference of the two. We must -explain, however, in the same way, the highest waves of -thirty-six to forty feet, which were doubtless due to similar -interference, crest agreeing with crest and trough with trough, -so that the resulting wave was the sum of the two which had -been divided, and had reached the same spot along different -courses. It would follow that the higher of the two waves -was about twenty-one feet high, the lower about eighteen -feet high; but as some height would be lost in the encounter -with the shore-line, wherever it lay, on which the waves -divided, we may fairly assume that in the open ocean, before -reaching the Sandwich group, the wave had a height of -nearly thirty feet from trough to crest. We read, in accordance -with this explanation, that “the regurgitations of the -sea were violent and complex, and continued through the -day.”</p> - -<p>The wave, regarded as a whole, seems to have reached -all the islands at the same time. Since this has not been -contradicted by later accounts, we are compelled to conclude -that the wave reached the group with its front parallel to the<span class="pagenum"><a id="Page_188">188</a></span> -length of the group, so that it must have come (arriving as it -did from the side towards which Hilo lies) from the north-east -It was, then, not the direct wave from Peru, but the -wave reflected from the shores of California, which produced -the most marked effects. We can understand well, this being -so, that the regurgitations of the sea were complex. Any -one who has watched the inflow of waves on a beach so -lying within an angle of the line that while one set of waves -comes straight in from the sea, another thwart set comes -from the shore forming the other side of the angle, will -understand how such waves differ from a set of ordinary -rollers. The crests of the two sets form a sort of network, -ever changing as each set rolls on; and considering any one -of the four-cornered meshes of this wave-net, the observer -will notice that while the middle of the raised sides rises -little above the surrounding level, because here the crests of -one set cross the troughs of the other, the corners of each -quadrangle are higher than they would be in either set taken -separately, while the middle of the four-cornered space is -correspondingly depressed. The reason is that at the -corners of the wave-net crests join with crests to raise the -water surface, while in the middle of the net (not the middle -of the sides, but the middle of the space enclosed by the -four sides) trough joins with trough to depress the water -surface.<a id="FNanchor_24" href="#Footnote_24" class="fnanchor">24</a></p> - -<p>We must take into account the circumstance that the wave -which reached Hawaii in May, 1876, was probably reflected -from the Californian coast, when we endeavour to determine -the rate at which the sea disturbance was propagated across<span class="pagenum"><a id="Page_189">189</a></span> -the Atlantic. The direct wave would have come sooner, -and may have escaped notice because arriving in the night-time, -as it would necessarily have done if a wave which -travelled to California, and thence, after reflection, to the -Sandwich group arrived there at a quarter before five in the -morning following the Peruvian earthquake. We shall be -better able to form an opinion on this point after considering -what happened in August, 1868.</p> - -<p>The earth-throe on that occasion was felt in Peru about -five minutes past five on the evening of August 13. Twelve -hours later, or shortly before midnight, August 13, Sandwich -Island time (corresponding to 5 p.m., August 14, Peruvian -time), the sea round the group of the Sandwich Isles rose in -a surprising manner, “insomuch that many thought the -islands were sinking, and would shortly subside altogether -beneath the waves. Some of the smaller islands were for a -time completely submerged. Before long, however, the sea -fell again, and as it did so the observers found it impossible -to resist the impression that the islands were rising bodily -out of the water. For no less than three days this strange -oscillation of the sea continued to be experienced, the most -remarkable ebbs and floods being noticed at Honolulu, on -the island of Woahoo.”</p> - -<p>The distance between Honolulu and Arica is about 6300 -statute miles; so that, if the wave travelled directly from the -shores of Peru to the Sandwich Isles, it must have advanced -at an average rate of about 525 miles an hour (about 450 -knots an hour). This is nearly half the rate at which the -earth’s surface near the equator is carried round by the -earth’s rotation, or is about the rate at which parts in latitude -62 or 63 degrees north are carried round by rotation; so -that the motion of the great wave in 1868 was fairly comparable -with one of the movements which we are accustomed -to regard as cosmical. I shall presently have something -more to say on this point.</p> - -<p>Now in May, 1876, as we have seen, the wave reached -Hawaii at about a quarter to five in the morning, corresponding<span class="pagenum"><a id="Page_190">190</a></span> -to about ten, Peruvian time. Since, then, the earthquake -was felt in Peru at half-past eight on the previous evening, -it follows that the wave, if it travelled directly from Peru, -must have taken about 13½ hours—or an hour and a half -longer, in travelling from Peru to the Sandwich Isles, than -it took in August, 1868. This is unlikely, because ocean-waves -travel nearly at the same rate in the same parts of the -ocean, whatever their dimensions, so only that they are large. -We have, then, in the difference of time occupied by the -wave in May, 1876, and in August, 1868, in reaching Hawaii, -some confirmation of the result to which we were led by the -arrival of the wave simultaneously at all the islands of the -Sandwich group—the inference, namely, that the observed -wave had reached these islands after reflection from the -Californian shore-line. As the hour when the direct wave -probably reached Hawaii was about a quarter past three in -the morning, when not only was it night-time but also a -time when few would be awake to notice the rise and fall of -the sea, it seems not at all improbable that the direct wave -escaped notice, and that the wave actually observed was the -reflected wave from California. The direction, also, in which -the oscillation was first observed corresponds well with this -explanation.</p> - -<p>It is clear that the wave which traversed the Pacific in -May, 1876, was somewhat inferior in size to that of August, -1868, which therefore still deserves to be called (as I then -called it) the greatest sea-wave ever known. The earthquake, -indeed, which preceded the oceanic disturbance of -1868 was far more destructive than that of May, 1876, and -the waves which came in upon the Peruvian and Bolivian -shores were larger. Nevertheless, the wave of May, 1876, -was not so far inferior to that of August, 1868, but that its -course could be traced athwart the entire extent of the -Pacific Ocean.</p> - -<p>When we consider the characteristic features of the -Peruvian and Chilian earthquakes, and especially when we -note how wide is the extent of the region over which their<span class="pagenum"><a id="Page_191">191</a></span> -action is felt in one way or another, it can scarcely be -doubted that the earth’s Vulcanian energies are at present -more actively at work throughout that region than in any -other. There is nothing so remarkable, one may even say -so stupendous, in the history of subterranean disturbance as -the alternation of mighty earth-throes by which, at one time, -the whole of the Chilian Andes seem disturbed and anon -the whole of the Peruvian Andes. In Chili scarcely a year -ever passes without earthquakes, and the same may be said -of Peru; but so far as great earthquakes are concerned the -activity of the Peruvian region seems to synchronize with the -comparative quiescence of the Chilian region, and <i xml:lang="la" lang="la">vice versâ</i>. -Thus, in 1797, the terrible earthquake occurred which is -known as the earthquake of Riobamba, which affected the -entire Peruvian earthquake region. Thirty years later a -series of tremendous throes shook the whole of Chili, permanently -elevating its long line of coast to the height of -several feet. During the last twelve years the Peruvian region -has in turn been disturbed by great earthquakes. It should -be added that between Chili and Peru there is a region about -five hundred miles in length in which scarcely any volcanic -action has been observed. And singularly enough, “this -very portion of the Andes, to which one would imagine that -the Peruvians and Chilians would fly as to a region of safety, -is the part most thinly inhabited; insomuch that, as Von -Buch observes, it is in some places entirely deserted.”</p> - -<p>One can readily understand that this enormous double -region of earthquakes, whose oscillations on either side of -the central region of comparative rest may be compared to -the swaying of a mighty see-saw on either side of its point -of support, should be capable of giving birth to throes propelling -sea-waves across the Pacific Ocean. The throe -actually experienced at any given place is relatively but an -insignificant phenomenon: it is the disturbance of the entire -region over which the throe is felt which must be considered -in attempting to estimate the energy of the disturbing cause. -The region shaken by the earthquake of 1868, for instance,<span class="pagenum"><a id="Page_192">192</a></span> -was equal to at least a fourth of Europe, and probably to -fully one-half. From Quito southwards as far as Iquique—or -along a full third part of the length of the South American -Andes—the shock produced destructive effects. It was also -distinctly felt far to the north of Quito, far to the south of -Iquique, and inland to enormous distances. The disturbing -forces which thus shook 1,000,000 square miles of the earth’s -surface must have been of almost inconceivable energy. If -directed entirely to the upheaval of a land region no larger -than England, those forces would have sufficed to have -destroyed utterly every city, town, and village within such a -region; if directed entirely to the upheaval of an oceanic -region, they would have been capable of raising a wave which -would have been felt on every shore-line of the whole earth. -Divided even between the ocean on the one side and a land -region larger than Russia in Europe on the other, those -Vulcanian forces shook the whole of the land region, and sent -athwart the largest of our earth’s oceans a wave which ran -in upon shores 10,000 miles from the centre of disturbance -with a crest thirty feet high. Forces such as these may fairly -be regarded as cosmical; they show unmistakably that the -earth has by no means settled down into that condition of -repose in which some geologists still believe. We may ask -with the late Sir Charles Lyell whether, after contemplating -the tremendous energy thus displayed by the earth, any -geologist will continue to assert that the changes of relative -level of land and sea, so common in former ages of the world, -have now ceased? and agree with him that if, in the face of -such evidence, a geologist persists in maintaining this -favourite dogma, it would be vain to hope, by accumulating -proofs of similar convulsions during a series of ages, to shake -the tenacity of his conviction—</p> - -<div class="poem-container"> -<div class="poem"><div class="stanza"> -<span class="iq">“Si fractus illabatur orbis,<br /></span> -<span class="i0">Impavidum ferient ruinæ.”<br /></span> -</div></div> -</div> - -<p>But there is one aspect in which such mighty sea-waves -as, in 1868 and again in May, 1876, have swept over the surface -of our terrestrial oceans, remains yet to be considered.</p> - -<p><span class="pagenum"><a id="Page_193">193</a></span> -The oceans and continents of our earth must be clearly -discernible from her nearer neighbours among the planets—from -Venus and Mercury on the inner side of her path -around the sun, and from Mars (though under less favourable -conditions) from the outer side. When we consider, -indeed, that the lands and seas of Mars can be clearly -discerned with telescopic aid from our earth at a distance of -forty millions of miles, we perceive that our earth, seen from -Venus at little more than half this distance, must present -a very interesting appearance. Enlarged, owing to greater -proximity, nearly fourfold, having a diameter nearly twice as -great as that of Mars, so that at the same distance her disc -would seem more than three times as large, more brightly -illuminated by the sun in the proportion of about five to two, -she would shine with a lustre exceeding that of Mars, when in -full brightness in the midnight sky, about thirty times; and all -her features would of course be seen with correspondingly -increased distinctness. Moreover, the oceans of our earth -are so much larger in relative extent than those of Mars, -covering nearly three-fourths instead of barely one-half of the -surface of the world they belong to, that they would appeal -as far more marked and characteristic features than the seas -and lakes of Mars. When the Pacific Ocean, indeed, occupies -centrally the disc of the earth which at the moment is -turned towards any planet, nearly the whole of that disc -must appear to be covered by the ocean. Under such -circumstances the passage of a wide-spreading series of waves -over the Pacific, at the rate of about 500 miles an hour, is a -phenomenon which could scarcely fail to be discernible from -Venus or Mercury, if either planet chanced to be favourably -placed for the observation of the earth—always supposing -there were observers in Mercury or Venus, and that these -observers were provided with powerful telescopes.</p> - -<p>It must be remembered that the waves which spread -over the Pacific on August 13–14, 1868, and again on May -9–10, 1876, were not only of enormous range in length -(measured along crest or trough), but also of enormous<span class="pagenum"><a id="Page_194">194</a></span> -breadth (measured from crest to crest, or from trough to -trough). Were it otherwise, indeed, the progress of a wave -forty or fifty feet high (at starting, and thirty-five feet high -after travelling 6000 miles), at the rate of 500 miles per -hour, must have proved destructive to ships in the open -ocean as well as along the shore-line. Suppose, for instance, -the breadth of the wave from crest to crest one mile, then, in -passing under a ship at the rate of 500 miles per hour, the -wave would raise the ship from trough to crest—that is, -through a height of forty feet—in one-thousandth part of an -hour (for the distance from trough to crest is but half the -breadth of the wave), or in less than four seconds, lowering it -again in the same short interval of time, lifting and lowering it -at the same rate several successive times. The velocity with -which the ship would travel upwards and downwards would -be greatest when she was midway in her ascent and descent, -and would then be equal to about the velocity with which a -body strikes the ground after falling from a height of four -yards. It is hardly necessary to say that small vessels subjected -to such tossing as this would inevitably be swamped. -On even the largest ships the effect of such motion would be -most unpleasantly obvious. Now, as a matter of fact, the -passage of the great sea-wave in 1868 was not noticed at all -on board ships in open sea. Even within sight of the shore -of Peru, where the oscillation of the sea was most marked, -the motion was such that its effects were referred to the -shore. We are told that observers on the deck of a United -States’ war steamer distinctly saw the “peaks of the mountains -in the chain of the Cordilleras wave to and fro like reeds in -a storm;” the fact really being that the deck on which they -stood was swayed to and fro. This, too, was in a part of -the sea where the great wave had not attained its open sea -form, but was a rolling wave, because of the shallowness of -the water. In the open sea, we read that the passage of the -great sea-wave was no more noticed than is the passage of -the tidal-wave itself. “Among the hundreds of ships which -were sailing upon the Pacific when its length and breadth<span class="pagenum"><a id="Page_195">195</a></span> -were traversed by the great sea-wave, there was not one in -which any unusual motion was perceived.” The inference -is clear, that the slope of the advancing and following faces -of the great wave was very much less than in the case above -imagined; in other words, that the breadth of the wave -greatly exceeded one mile—amounting, in fact, to many -miles.</p> - -<p>Where the interval between the passage of successive -wave-crests was noted, we can tell the actual breadth of the -wave. Thus, at the Samoan Isles, in 1868, the crests succeeded -each other at intervals of sixteen minutes, corresponding -to eight minutes between crest and trough. But we have -seen, that if the waves were one mile in breadth, the corresponding -interval would be only four seconds, or only one -120th part of eight minutes: it follows, then, that the breadth -of the great wave, where it reached the Samoan Isles in -1868, was about 120 miles.</p> - -<p>Now a wave extending right athwart the Pacific Ocean, -and having a cross breadth of more than 120 miles, would -be discernible as a marked feature of the disc of our earth, -seen under the conditions described above, either from Mercury -or Venus. It is true that the slope of the wave’s -advancing and following surfaces would be but slight, yet -the difference of the illumination under the sun’s rays would -be recognizable. Then, also, it is to be remembered that -there was not merely a single wave, but a succession of many -waves. These travelled also with enormous velocity; and -though at the distance of even the nearest planet, the apparent -motion of the great wave, swift though it was in reality, -would be so far reduced that it would have to be estimated -rather than actually seen, yet there would be no difficulty in -thus perceiving it with the mind’s eye. The rate of motion -indeed would almost be exactly the same as that of the -equatorial part of the surface of Mars, in consequence of the -planet’s rotation; and this (as is well known to telescopists), -though not discernible directly, produces, even in a few -minutes, changes which a good eye can clearly recognize.<span class="pagenum"><a id="Page_196">196</a></span> -We can scarcely doubt then that if our earth were so situated -at any time when one of the great waves generated by Peruvian -earthquakes in traversing the Pacific, that the hemisphere -containing this ocean were turned fully illuminated -towards Venus (favourably placed for observing her), the -disturbance of the Pacific could be observed and measured -by telescopists on that planet.</p> - -<p>Unfortunately there is little chance that terrestrial observers -will ever be able to watch the progress of great waves -athwart the oceans of Mars, and still less that any disturbance -of the frame of Venus should become discernible to us -by its effects. We can scarce even be assured that there -are lands and seas on Venus, so far as direct observation is -concerned, so unfavourably is she always placed for observation; -and though we see Mars under much more favourable -conditions, his seas are too small and would seem to -be too shallow (compared with our own) for great waves to -traverse them such as could be discerned from the earth.</p> - -<p>Yet it is well to remember the possibility that changes -may at times take place in the nearer planets—the terrestrial -planets, as they are commonly called, Mars, Venus, -and Mercury—such as telescopic observation under favourable -conditions might detect. Telescopists have, indeed, -described apparent changes, lasting only for a short time, in -the appearance of one of these planets, Mars, which may -fairly be attributed to disturbances affecting its surface in no -greater degree than the great Peruvian earthquakes have -affected for a time the surface of our earth. For instance, -the American astronomer Mitchel says that on the night of -July 12, 1845, bright polar snows of Mars exhibited an -appearance never noticed at any preceding or succeeding -observation. In the very centre of the white surface appeared -a dark spot, which retained its position during several hours: -on the following evening not a trace of the spot could be -seen. Again the same observer says that on the evening of -August 30, 1845, he observed for the first time a small -bright spot, nearly or quite round, projecting out of the<span class="pagenum"><a id="Page_197">197</a></span> -lower side of the polar spot. “In the early part of the -evening,” he says, “the small bright spot seemed to be partly -buried in the large one. After the lapse of an hour or more -my attention was again directed to the planet, when I was -astonished to find a manifest change in the position of the -small bright spot. It had apparently separated from the -large spot, and the edges alone of the two were now in contact, -whereas when first seen they overlapped by an amount -quite equal to one-third of the diameter of the small one. -This, however, was merely an optical phenomenon, for on -the next evening the spots went through the same apparent -changes as the planet went through the corresponding part -of its rotation. But it showed the spots to be real ice -masses. The strange part of the story is that in the course -of a few days the smaller spot, which must have been a mass -of snow and ice as large as Novaia Zemlia, gradually disappeared. -Probably some great shock had separated an -enormous field of ice from the polar snows, and it had -eventually been broken up and its fragments carried away -from the Arctic regions by currents in the Martian oceans. It -appears to me that the study of our own earth, and of the -changes and occasional convulsions which affect its surface, -gives to the observation of such phenomena as I have just -described a new interest. Or rather, perhaps, it is not too -much to say that the telescopic observations of the planets -derive their only real interest from such considerations.</p> - -<p>I may note in conclusion, that while on the one hand -we cannot doubt that the earth is slowly parting with its -internal heat, and thus losing century by century a portion -of its Vulcanian energy, such phenomena as the Peruvian -earthquakes show that the loss of energy is taking place so -slowly that the diminution during many ages is almost imperceptible. -As I have elsewhere remarked, “When we see -that while mountain ranges were being upheaved or valleys -depressed to their present position, race after race and type -after type lived out on the earth the long lives which belong -to races and to types, we recognize the great work which the<span class="pagenum"><a id="Page_198">198</a></span> -earth’s subterranean forces are still engaged upon. Even -now continents are being slowly depressed or upheaved, -even now mountain ranges are being raised to a different -level, table-lands are being formed, great valleys are being -gradually scooped out; old shore-lines shift their place, old -soundings vary; the sea advances in one place and retires -in another; on every side nature’s plastic hand is still at -work, modelling and remodelling the earth, and making it -constantly a fit abode for those who dwell upon it.”</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_199">199</a></span></p> - -<div class="chapter"> -<h2><a id="STRANGE_SEA_CREATURES"></a><i>STRANGE SEA CREATURES.</i></h2> -</div> - -<blockquote> - -<p>“We ought to make up our minds to dismiss as idle prejudices, or, -at least, suspend as premature, any preconceived notion of what <em>might</em>, -or what <em>ought to</em>, <em>be</em> the order of nature, and content ourselves with -observing, as a plain matter of fact, what <em>is</em>.”—Sir <span class="smcap">J. Herschel</span>, -“Prelim. Disc.” page 79.</p></blockquote> - -<p class="p2 in0">The fancies of men have peopled three of the four so-called -elements, earth, air, water, and fire, with strange forms of -life, and have even found in the salamander an inhabitant -for the fourth. On land the centaur and the unicorn, in the -air the dragon and the roc, in the water tritons and mermaids, -may be named as instances among many of the -fabulous creatures which have been not only imagined but -believed in by men of old times. Although it may be -doubted whether men have ever invented any absolutely -imaginary forms of life, yet the possibility of combining -known forms into imaginary, and even impossible, forms, -must be admitted as an important element in any inquiry -into the origin of ideas respecting such creatures as I have -named. One need only look through an illuminated manuscript -of the Middle Ages to recognize the readiness with -which imaginary creatures can be formed by combining, or -by exaggerating, the characteristics of known animals. -Probably the combined knowledge and genius of all the -greatest zoologists of our time would not suffice for the -invention of an entirely new form of animal which yet should -be zoologically possible; but to combine the qualities of -several existent animals in a single one, or to conceive an<span class="pagenum"><a id="Page_200">200</a></span> -animal with some peculiarity abnormally developed, is within -the capacity of persons very little acquainted with zoology, -nay, is perhaps far easier to such persons than it would be -to an Owen, a Huxley, or a Darwin. In nearly every case, -however, the purely imaginary being is to be recognized by -the utter impossibility of its actual existence. If it be a -winged man, arms and wings are both provided, but the -pectoral muscles are left unchanged. A winged horse, in -like manner, is provided with wings, without any means of -working them. A centaur, as in the noble sculptures of -Phidias, has the upper part of the trunk of a man superadded, -not to the hind quarters of a horse or other quadruped, but -to the entire trunk of such an animal, so that the abdomen -of the human figure lies <em>between</em> the upper half of the human -trunk and the corresponding part of the horse’s trunk, an -arrangement anatomically preposterous. Without saying -that every fabulous animal which was anatomically and -zoologically possible, had a real antitype, exaggerated though -the fabulous form may have been, we must yet admit that -errors so gross marked the conception of all the really -imaginary animals of antiquity, that any fabulous animal -found to accord fairly well with zoological possibilities may -be regarded, with extreme probability, as simply the exaggerated -presentation of some really existent animal. The -inventors of centaurs, winged and man-faced bulls, many-headed -dogs, harpies, and so forth, were utterly unable to -invent a possible new animal, save by the merest chance, -the probability of which was so small that it may fairly be -disregarded.</p> - -<p>This view of the so-called fabulous animals of antiquity -has been confirmed by the results of modern zoological -research. The merman, zoologically possible (not in all -details, of course, but generally), has found its antitype in -the dugong and the manatee; the roc in the condor, or -perhaps in those extinct species whose bones attest their -monstrous proportions; the unicorn in the rhinoceros; even -the dragon in the pterodactyl of the green-sand; while the<span class="pagenum"><a id="Page_201">201</a></span> -centaur, the minotaur, the winged horse, and so forth, have -become recognized as purely imaginary creatures, which had -their origin simply in the fanciful combination of known -forms, no existent creatures having even suggested these -monstrosities.</p> - -<p>It is not to be wondered at that the sea should have -been more prolific in monstrosities and in forms whose real -nature has been misunderstood. Land animals cannot long -escape close observation. Even the most powerful and -ferocious beasts must succumb in the long run to man, and -in former ages, when the struggle was still undecided between -some race of animals and savage man, individual -specimens of the race must often have been killed, and the -true appearance of the animal determined. Powerful winged -animals might for a longer time remain comparatively -mysterious creatures even to those whom they attacked, or -whose flocks they ravaged. A mighty bird, or a pterodactylian -creature (a late survivor of a race then fast dying -out), might swoop down on his prey and disappear with it -too swiftly to be made the subject of close scrutiny, still less -of exact scientific observation. Yet the general characteristics -even of such creatures would before long be known. From -time to time the strange winged monster would be seen -hovering over the places where his prey was to be found. -Occasionally it would be possible to pierce one of the race -with an arrow or a javelin; and thus, even in those remote -periods when the savage progenitors of the present races of -man had to carry on a difficult contest with animals now -extinct or greatly reduced in power, it would become possible -to determine accurately the nature of the winged enemy. -But with sea creatures, monstrous, or otherwise, the case -would be very different. To this day we remain ignorant -of much that is hidden beneath the waves of the “hollow-sounding -and mysterious main.” Of far the greater number -of sea creatures, it may truly be said that we never see any -specimens except by accident, and never obtain the body of -any except by very rare accident. Those creatures of the<span class="pagenum"><a id="Page_202">202</a></span> -deep sea which we are best acquainted with, are either those -which are at once very numerous and very useful as food or -in some other way, or else those which are very rapacious -and thus expose themselves, by their attacks on men, to -counter-attack and capture or destruction. In remote times, -when men were less able to traverse the wide seas, when, -on the one hand, attacks from great sea creatures were more -apt to be successful, while, on the other, counter-attack was -much more dangerous, still less would be known about the -monsters of the deep. Seen only for a few moments as he -seized his prey, and then sinking back into the depths, a -sea monster would probably remain a mystery even to those -who had witnessed his attack, while their imperfect account -of what they had seen would be modified at each repetition -of the story, until there would remain little by which the -creature could be identified, even if at some subsequent -period its true nature were recognized. We can readily -understand, then, that among the fabulous creatures of -antiquity, even of those which represented actually existent -races incorrectly described, the most remarkable, and those -zoologically the least intelligible, would be the monsters of -the deep sea. We can also understand that even the -accounts which originally corresponded best with the truth -would have undergone modifications much more noteworthy -than those affecting descriptions of land animals or winged -creatures—simply because there would be small chance of -any errors thus introduced being corrected by the study of -freshly discovered specimens.</p> - -<p>We may, perhaps, explain in this way the strange account -given by Berosus of the creature which came up from the -Red Sea, having the body of a fish but the front and head of -a man. We may well believe that this animal was no other -than a dugong, or halicore (a word signifying sea-maiden), -a creature inhabiting the Indian Ocean to this day, and which -might readily find its way into the Red Sea. But the account -of the creature has been strangely altered from the original -narrative, if at least the original narrative was correct. For,<span class="pagenum"><a id="Page_203">203</a></span> -according to Berosus, the animal had two human feet which -projected from each side of the tail; and, still stranger, it -had a human voice and human language. “This strange -monster sojourned among the rude people during the day, -taking no food, but retiring to the sea again at night, and -continued for some time teaching them the arts of civilized -life.” A picture of this stranger is said to have been preserved -at Babylon for many centuries. With a probable -substratum of truth, the story in its latest form is as fabulous -as Autolycus’s “ballad of a fish that appeared upon the -coast, on Wednesday the fourscore of April, forty thousand -fathoms above water, and sang a ballad against the hard -hearts of maids.”</p> - -<p>It is singular, by the way, how commonly the power of -speech, or at least of producing sounds resembling speech -or musical notes, was attributed to the creature which -imagination converted into a man-fish or woman-fish. -Dugongs and manatees make a kind of lowing noise, which -could scarcely be mistaken under ordinary conditions for the -sound of the human voice. Yet, not only is this peculiarity -ascribed to the mermaid and siren (the merman and triton -having even the supposed power of blowing on conch-shells), -but in more recent accounts of encounters with creatures -presumably of the seal tribe and allied races, the same -feature is to be noticed. The following account, quoted by -Mr. Gosse from a narrative by Captain Weddell, the well-known -geographer, is interesting for this reason amongst -others. It also illustrates well the mixture of erroneous details -(the offspring, doubtless, of an excited imagination) with the -correct description of a sea creature actually seen:—“A -boat’s crew were employed on Hall’s Island, when one of -the crew, left to take care of some produce, saw an animal -whose voice was musical. The sailor had lain down, and at -ten o’clock he heard a noise resembling human cries, and as -daylight in these latitudes never disappears at this season” -(the Antarctic summer), “he rose and looked around, but, -on seeing no person, returned to bed. Presently he heard<span class="pagenum"><a id="Page_204">204</a></span> -the noise again; he rose a second time, but still saw nothing. -Conceiving, however, the possibility of a boat being upset, -and that some of the crew might be clinging to detached -rocks, he walked along the beach a few steps and heard the -noise more distinctly but in a musical strain. Upon searching -around, he saw an object lying on a rock a dozen yards -from the shore, at which he was somewhat frightened. The -face and shoulders appeared of human form and of a reddish -colour; over the shoulders hung long green hair; the tail -resembled that of the seal, but the extremities of the arms -he could not see distinctly. The creature continued to -make a musical noise while he gazed about two minutes, and -on perceiving him it disappeared in an instant. Immediately, -when the man saw his officer, he told this wild tale, -and to add weight to his testimony (being a Romanist) he -made a cross on the sand, which he kissed, as making oath -to the truth of his statement. When I saw him he told the -story in so clear and positive a manner, making oath to its -truth, that I concluded he must really have seen the animal -he described, or that it must have been the effects of a disturbed -imagination.”</p> - -<p>In this story all is consistent with the belief that the -sailor saw an animal belonging to the seal family (of a -species unknown to him), except the green hair. But the -hour was not very favourable to the discerning of colour, -though daylight had not quite passed away, and as Gosse -points out, since golden-yellow fur and black fur are found -among Antarctic seals, the colours may be intermingled in -some individuals, producing an olive-green tint, which, by -contrast with the reddish skin, might be mistaken for a full -green. Considering that the man had been roused from -sleep and was somewhat frightened, he would not be likely -to make very exact observations. It will be noticed that it -was only at first that he mistook the sounds made by the -creature for human cries; afterwards he heard only the same -<em>noise</em>, but in a musical strain. Now with regard to the -musical sounds said to have been uttered by this creature,<span class="pagenum"><a id="Page_205">205</a></span> -and commonly attributed to creatures belonging to families -closely allied to the seals, I do not know that any attempt -has yet been made to show that these families possess the -power of emitting sounds which can properly be described -as musical. It is quite possible that the Romanist sailor’s -ears were not very nice, and that any sound softer than a -bellow seemed musical to him. Still, the idea suggests itself -that possibly seals, like some other animals, possess a note -not commonly used, but only as a signal to their mates, and -never uttered when men or other animals are known to be -near. It appears to me that this is rendered probable by -the circumstance that seals are fond of music. Darwin -refers to this in his treatise on Sexual Selection (published -with his “Descent of Man”), and quotes a statement to the -effect that the fondness of seals for music “was well known -to the ancients, and is often taken advantage of by hunters -to the present day.” The significance of this will be understood -from Darwin’s remark immediately following, that -“with all these animals, the males of which during the season -of courtship incessantly produce musical notes or mere -rhythmical sounds, we must believe that the females are -able to appreciate them.”</p> - -<p>The remark about the creature’s arms seems strongly to -favour the belief that the sailor intended his narrative to be -strictly truthful. Had he wished to excite the interest of his -comrades by a marvellous story, he certainly would have -described the creature as having well-developed human -hands.</p> - -<p>Less trustworthy by far seem some of the stories which -have been told of animals resembling the mermaid of antiquity. -It must always be remembered, however, that in all -probability we know very few among the species of seals and -allied races, and that some of these species may present, in -certain respects and perhaps at a certain age, much closer -resemblance to the human form than the sea-lion, seal, -manatee, or dugong.</p> - -<p>We cannot, for instance, attach much weight to the following<span class="pagenum"><a id="Page_206">206</a></span> -story related by Hudson, the famous navigator:—“One -of our company, looking overboard, saw a mermaid -and calling up some of the company to see her, one more -came up, and by that time she was come close to the ship’s -side, looking earnestly on the men. A little after a sea -came and overturned her. From the navel upward her back -and breasts were like a woman’s, as they say that saw her; -her body as big as one of us; her skin very white; and long -hair hanging down behind, of colour black. In her going -down they saw her tail, which was like the tail of a porpoise -and speckled like a mackerel.” If Hudson himself had seen -and thus described the creature it would have been possible -to regard the story with some degree of credence; but his -account of what Thomas Hilles and Robert Rayner, men -about whose character for veracity we know nothing, <em>said</em> -they saw, is of little weight. The skin very white, and long -hair hanging down behind, are especially suspicious features -of the narrative; and were probably introduced to dispose -of the idea, which others of the crew may have advanced, -that the creature was only some kind of seal after all. The -female seal (<i>Phoca Greenlandica</i> is the pretty name of the -animal) is not, however, like the male, tawny grey, but -dusky white, or yellowish straw-colour, with a tawny tint on -the back. The young alone could be called “very white.” -They are so white in fact as scarcely to be distinguishable -when lying on ice and snow, a circumstance which, as -Darwin considers, serves as a protection for these little -fellows.</p> - -<p>The following story, quoted by Gosse from Dr. Robert -Hamilton’s able “History of the Whales and Seals,” compares -favourably in some respects with the last narrative:—“It -was reported that a fishing-boat off the island of Yell, one of -the Shetland group, had captured a mermaid by its getting -entangled in the lines! The statement is, that the animal -is about three feet long, the upper part of the body resembling -the human, with protuberant mammæ like a woman; -the face, the forehead, and neck, were short, and resembling<span class="pagenum"><a id="Page_207">207</a></span> -those of a monkey; the arms, which were small, were kept -folded across the breast; the fingers were distinct, not -webbed; a few stiff long bristles were on the top of the head, -extending down to the shoulders, and these it could erect -and depress at pleasure, something like a crest. The inferior -part of the body was like a fish. The skin was smooth and -of a grey colour. It offered no resistance, nor attempted to -bite, but uttered a low, plaintive sound. The crew, six in -number, took it within their boat; but superstition getting -the better of curiosity, they carefully disentangled it from the -lines and a hook which had accidentally fastened in the -body, and returned it to its native element. It instantly -dived, descending in a perpendicular direction.” “They -had the animal for three hours within the boat; the body -was without scales or hair; of a silvery grey colour above, -and white below, like the human skin; no gills were observed, -nor fins on the back or belly. The tail was like -that of the dog-fish; the mammæ were about as large as those -of a woman; the mouth and lips were very distinct, and -resembled the human.”</p> - -<p>This account, if accepted in all its details, would certainly -indicate that an animal of some species before unknown had -been captured. But it is doubtful how much reliance can -be placed on the description of the animal. Mr. Gosse, -commenting upon the case, says that the fishermen cannot -have been affected by fear in such sort that their imagination -exaggerated the resemblance of the creature to the -human form. “For the mermaid,” he says, “is not an -object of terror to the fishermen; it is rather a welcome -guest, and danger is to be apprehended only from its experiencing -bad treatment.” But then this creature had not -been treated as a specially welcome guest. The crew had captured -it; and probably not without some degree of violence; -for though it offered no resistance it uttered a plaintive cry. -And that hook which “had accidentally fastened in the -body” has a very suspicious look. If the animal could have -given its own account of the capture, probably the hook<span class="pagenum"><a id="Page_208">208</a></span> -would not have been found to have fastened in the body -altogether by accident. Be this as it may, the fishermen -were so far frightened that superstition got the better of -curiosity; so that, as they were evidently very foolish fellows, -their evidence is scarcely worth much. There are, however, -only two points in their narrative which do not seem easily -reconciled with the belief that they had captured a rather -young female of a species closely allied to the common seal—the -distinct unwebbed fingers and the small arms folded -across the breast. Other points in their description suggest -marked differences in degree from the usual characteristics -of the female seal; but these two alone seem to differ absolutely -in kind. Considering all the circumstances of the -narrative, we may perhaps agree with Mr. Gosse to this -extent, that, combined with other statements, the story induces -a strong suspicion that the northern seas may hold -forms of life as yet uncatalogued by science.</p> - -<p>The stories which have been related about monstrous -cuttle-fish have only been fabulous in regard to the dimensions -which they have attributed to these creatures. Even -in this respect it has been shown, quite recently, that some -of the accounts formerly regarded as fabulous fell even short -of the truth. Pliny relates, for instance, that the body of a -monstrous cuttle-fish, of a kind known on the Spanish coast, -weighed, when captured, 700 lbs., the head the same, the -arms being 30 feet in length. The entire weight would probably -have amounted to about 2000 lbs. But we shall presently -see that this weight has been largely exceeded by -modern specimens. It was, however, in the Middle Ages -that the really fabulous cuttle-fish flourished—the gigantic -kraken, “liker an island than an animal,” according to credulous -Bishop Pontoppidan, and able to destroy in its -mighty arms the largest galleons and war ships of the fourteenth -and fifteenth centuries.</p> - -<p>It is natural that animals really monstrous should be -magnified by the fears of those who have seen or encountered -them, and still further magnified afterwards by tradition.<span class="pagenum"><a id="Page_209">209</a></span> -Some specimens of cuttle-fish which have been -captured wholly, or in part, indicate that this creature sometimes -attains such dimensions that but little magnifying -would be needed to suggest even the tremendous proportions -of the fabulous kraken. In 1861, the French war-steamer -<i>Alecton</i> encountered a monstrous cuttle, on the -surface of the sea, about 120 miles north-east of Teneriffe. -The crew succeeded in slipping a noose round the body, but -unfortunately the rope slipped, and, being arrested by the -tail fin, pulled off the tail. This was hauled on board, and -found to weigh over 40 lbs. From a drawing of the animal, -the total length without the arms was estimated at 50 feet, -and the weight at 4000 lbs., nearly twice the weight of -Pliny’s monstrous cuttle-fish, long regarded as fabulous. In -one respect this creature seems to have been imperfect, the -two long arms usually possessed by cuttle-fish of the kind -being wanting. Probably it had lost these long tentacles in -a recent encounter with some sea enemy, perhaps one of its -own species. Quite possibly it may have been such recent -mutilation which exposed this cuttle-fish to successful -attack by the crew of the <i>Alecton</i>.</p> - -<p>A cuttle-fish of about the same dimensions was encountered -by two fishermen in 1873, in Conception Bay, -Newfoundland. When they attacked it, the creature threw -its long arms across the boat, but the fishermen with an axe -cut off these tentacles, on which the cephalopod withdrew in -some haste. One of the arms was preserved, after it had -lost about 6 feet of its length. Even thus reduced it -measured 19 feet; and as the fishermen estimate that the arm -was struck off about 10 feet from the body, it follows that the -entire length of the limb must have been about 35 feet. -They estimated the body at 60 feet in length and 5 feet in -diameter—a monstrous creature! It was fortunate for these -fishermen that they had an axe handy for its obtrusive tentacles, -as with so great a mass and the great propulsive -power possessed by all cephalopods, it might readily have -upset their small boat. Once in the water, they would have<span class="pagenum"><a id="Page_210">210</a></span> -been at the creature’s mercy—a quality which, by all accounts, -the cuttle-fish does not possess to any remarkable -extent.</p> - -<p>Turn we, however, from the half fabulous woman-fish, -and the exaggeratedly monstrous cuttle-fish, to the famous -sea-serpent, held by many to be the most utterly fabulous of -all fabled creatures, while a few, including some naturalists -of distinction, stoutly maintain that the creature has a real -existence, though whether it be rightly called a sea-serpent -or not is a point about which even believers are extremely -doubtful.</p> - -<p>It may be well, in the first place, to remark that in -weighing the evidence for and against the existence of this -creature, and bearing on the question of its nature (if its -existence be admitted), we ought not to be influenced by -the manifest falsity of a number of stories relating to supposed -encounters with this animal. It is probable that, but -for these absurd stories, the well-authenticated narratives -relating to the creature, whatever it may be, which has been -called the sea-serpent, would have received much more -attention than has heretofore been given to them. It is also -possible that some narratives would have been published -which have been kept back from the fear lest a truthful -(though possibly mistaken) account should be classed with -the undoubted untruths which have been told respecting the -great sea-serpent. It cannot be denied that in the main the -inventions and hoaxes about the sea-serpent have come -chiefly from American sources. It is unfortunately supposed -by too many of the less cultured sons of America that (to use -Mr. Gosse’s expression) “there is somewhat of wit in gross -exaggerations or hoaxing inventions.” Of course an -American gentleman—using the word “in that sense in which -every man may be a gentleman,” as Twemlow hath it—would -as soon think of uttering a base coin as a deliberate untruth -or foolish hoax. But it is thought clever, by not a few in -America who know no better, to take any one in by an -invention. Some, perhaps but a small number, of the newspapers<span class="pagenum"><a id="Page_211">211</a></span> -set a specially bad example in this respect, giving -room in their columns for pretended discoveries in various -departments of science, elaborate accounts of newly discovered -animals, living or extinct, and other untruths which -would be regarded as very disgraceful indeed by English -editors. Such was the famous “lunar hoax,” published in -the New York <cite>Sun</cite> some forty years ago; such the narrative, -in 1873, of a monstrous fissure which had been discerned in -the body of the moon, and threatened to increase until the -moon should be cloven into two unequal parts; such the -fables which have from time to time appeared respecting -the sea-serpent. But it would be as unreasonable to reject, -because of these last-named fables, the narratives which have -been related by quiet, truth-loving folk, and have borne close -and careful scrutiny, as it would be to reject the evidence -given by the spectroscope respecting the existence of iron -and other metals in the sun because an absurd story had -told how creatures in the moon had been observed to make -use of metal utensils or to adorn the roofs of their temples -with metallic imitations of wreathed flames.</p> - -<p>The oldest accounts on record of the appearance of a -great sea creature resembling a serpent are those quoted by -Bishop Pontoppidan, in his description of the natural history -of his native country, Norway. Amongst these was one confirmed -by oath taken before a magistrate by two of the crew -of a ship commanded by Captain de Ferry, of the Norwegian -navy. The captain and eight men saw the animal, near -Molde, in August, 1747. They described it as of the general -form of a serpent, stretched on the surface in receding coils -(meaning, probably, the shape assumed by the neck of a -swan when the head is drawn back). The head, which resembled -that of a horse, was raised two feet above the -water.</p> - -<p>In August, 1817, a large marine animal, supposed to be -a serpent, was seen near Cape Ann, Massachusetts. Eleven -witnesses of good reputation gave evidence on oath before -magistrates. One of these magistrates had himself seen the<span class="pagenum"><a id="Page_212">212</a></span> -creature, and corroborated the most important points of the -evidence given by the eleven witnesses. The creature had -the appearance of a serpent, dark brown in colour (some -said mottled), with white under the head and neck. Its -length was estimated at from 50 to 100 feet. The head was -in shape like a serpent’s, but as large as a horse’s. No mane -was noticed. Five of the witnesses deposed to protuberances -on the back; four said the back was straight; the -other two gave no opinion on this point. The magistrate -who had seen the animal considered the appearance of protuberances -was due to the bendings of the body while in -rapid motion.</p> - -<p>In 1848, when the captain of the British frigate <i>Dædalus</i> -had published an account of a similar animal seen by him -and several of his officers and crew, the Hon. Colonel T. H. -Perkins, of Boston, who had seen the animal on the occasion -just mentioned in 1817, gave an account (copied from a -letter written in 1820) of what he had witnessed. It is -needless to quote those points which correspond with what -has been already stated. Colonel Perkins noticed “an -appearance in the front of the head like a single horn, about -nine inches to a foot in length, shaped like a marlinspike, -which will presently be explained. I left the place,” he -proceeds, “fully satisfied that the reports in circulation, -though differing in details, were essentially correct.” He -relates how a person named Mansfield, “one of the most -respectable inhabitants of the town, who had been such an -unbeliever in the existence of this monster that he had not -given himself the trouble to go from his house to the harbour -when the report was first made,” saw the animal from a bank -overlooking the harbour. Mr. Mansfield and his wife agreed -in estimating the creature’s length at 100 feet. Several -crews of coasting vessels saw the animal, <em>in some instances -within a few yards</em>. “Captain Tappan,” proceeds Colonel -Perkins, “a person well known to me, saw him with his head -above water two or three feet, at times moving with great -rapidity, at others slowly. He also saw what explained the<span class="pagenum"><a id="Page_213">213</a></span> -appearance which I have described of a horn on the front of -the head. This was doubtless what was observed by Captain -Tappan to be the tongue, thrown in an upright position -from the mouth, and having the appearance which I have -given to it. One of the revenue cutters, whilst in the -neighbourhood of Cape Ann, had an excellent view of him -at a few yards’ distance; he moved slowly, and upon the -appearance of the vessel sank and was seen no more.”</p> - -<p>Fifteen years later, in May 1833, five British officers—Captain -Sullivan, Lieutenants Maclachlan and Malcolm of -the Rifle Brigade, Lieutenant Lyster of the Artillery, and -Mr. Snee of the Ordnance—when cruising in a small yacht -off Margaret’s Bay, not far from Halifax, “saw the head and -neck of some denizen of the deep, precisely like those of a -common snake, in the act of swimming, the head so elevated -and thrown forward by the curve of the neck as to enable us -to see the water under and beyond it.” They judged its -length to exceed 80 feet. “There could be no mistake nor -delusion, and we were all perfectly satisfied that we had -been favoured with a view of the ‘true and veritable sea-serpent,’ -which had been generally considered to have -existed only in the brain of some Yankee skipper, and -treated as a tale not entitled to belief.” Dowling, a man-of-war’s -man they had along with them, made the following -unscientific but noteworthy comment: “Well, I’ve sailed in -all parts of the world, and have seen rum sights too in my -time, but this is the queerest thing I ever see.” “And -surely,” adds Captain Sullivan, “Jack Dowling was right.” -The description of the animal agrees in all essential respects -with previous accounts, but the head was estimated at about -six feet in length—considerably larger, therefore, than a -horse’s head.</p> - -<p>But unquestionably the account of the sea-serpent which -has commanded most attention was that given by the captain, -officers, and crew of the British frigate <i>Dædalus</i>, Captain -M’Quhæ, in 1848. The <cite>Times</cite> published on October 9, -1848, a paragraph stating that the sea-serpent had been seen<span class="pagenum"><a id="Page_214">214</a></span> -by the captain and most of the officers and crew of this ship, -on her passage home from the East Indies. The Admiralty -inquired at once into the truth of the statement, and the -following is abridged from Captain M’Quhæ’s official reply, -addressed to Admiral Sir W. H. Gage.</p> - -<p>“Sir,—In reply to your letter, requiring information as to -the truth of a statement published in the <cite>Times</cite> newspaper, -of a sea-serpent of extraordinary dimensions having been -seen from the <i>Dædalus</i>, I have the honour to inform you -that at 5 p.m., August 6 last, in latitude 24° 44´ S., longitude -9° 22´ E., the weather dark and cloudy, wind fresh from -N.W., with long ocean swell from S.W., the ship on the -port tack, heading N.E. by N., Mr. Sartoris, midshipman, -reported to Lieutenant E. Drummond (with whom, and Mr. -W. Barrett, the master, I was walking the quarter-deck) -something very unusual rapidly approaching the ship from -before the beam. The object was seen to be an enormous -serpent, with head and shoulders kept about four feet -constantly above the surface of the sea, as nearly as we -could judge; at least 60 feet of the animal was on the -surface, no part of which length was used, so far as we -could see, in propelling the animal either by vertical or -horizontal undulation. It passed quietly, <em>but so closely -under our lee quarter that, had it been a man of my acquaintance, -I should easily have recognized his features with -the naked eye</em>. It did not, while visible, deviate from its -course to the S.W., which it held on at the pace of from 12 -to 15 miles per hour, as if on some determined purpose. -The diameter of the serpent was from 15 to 16 inches -behind the head, which was, without any doubt, that of a -snake. Its colour was a dark brown, with yellowish white -about the throat. It did not once, while within the range -of view from our glasses, sink below the surface. It had no -fins, but something like the mane of a horse, or rather a -bunch of sea-weed, washed about its back. It was seen by -the quarter-master, the boatswain’s mate, and the man at -the wheel, in addition to myself and the officers above-<span class="pagenum"><a id="Page_215">215</a></span>mentioned. -I am having a drawing of the serpent made -from a sketch taken immediately after it was seen, which I -hope to have ready for my Lords Commissioners of the -Admiralty by to-morrow’s post.—Peter M’Quhæ, Captain.”</p> - -<p>The drawing here mentioned was published in the <cite>Illustrated -London News</cite> for October 28, 1848, being there -described as made “under the supervision of Captain -M’Quhæ, and his approval of the authenticity of the details -as to position and form.”</p> - -<p>The correspondence and controversy elicited by the -statement of Captain M’Quhæ were exceedingly interesting. -It is noteworthy, at the outset, that few, perhaps none, who -had read the original statement, suggested the idea of illusion, -while it need hardly perhaps be said that no one -expressed the slightest doubt as to the <i xml:lang="la" lang="la">bona fides</i> of Captain -M’Quhæ and his fellow-witnesses. These points deserve -attention, because, in recent times, the subject of the sea-serpent -has been frequently mentioned in public journals -and elsewhere as though no accounts of the creature had -ever been given which had been entitled to credence. I -proceed to summarise the correspondence which followed -M’Quhæ’s announcement. The full particulars will be -found in Mr. Gosse’s interesting work, the “Romance of -Natural History,” where, however, as it seems to me, the -full force of the evidence is a little weakened, for all save -naturalists, by the introduction of particulars not bearing -directly on the questions at issue.</p> - -<p>Among the earliest communications was one from Mr. J. -D. M. Stirling, a gentleman who, during a long residence in -Norway, had heard repeated accounts of the sea-serpent in -Norwegian seas, and had himself seen a fish or reptile at a -distance of a quarter of a mile, which, examined through -a telescope, corresponded in appearance with the sea-serpent -as usually described. This communication was chiefly interesting, -however, as advancing the theory that the supposed -sea-serpent is not a serpent at all, but a long-necked plesiosaurian. -This idea had been advanced earlier, but without<span class="pagenum"><a id="Page_216">216</a></span> -his knowledge, by Mr. E. Newman, the editor of the -<cite>Zoologist</cite>. Let us briefly inquire into the circumstances -which suggest the belief.</p> - -<p>If we consider the usual account of the sea-serpent, we -find one constant feature, which seems entirely inconsistent -with the belief that the creature can be a serpent. The -animal has always shown a large portion of its length, from -20 to 60 feet, above the surface of the water, and without any -evident signs of undulation, either vertically or horizontally. -Now, apart from all zoological evidence, our knowledge of -physical laws will not permit us to believe that the portion -thus visible above the surface was propelled by the undulations -of a portion concealed below the surface, unless this -latter portion largely exceeded the former in bulk. A true -fish does not swim for any length of time with any but a very -small portion of its body above water; probably large eels -never show even a head or fin above water for more than a -few seconds when not at rest. Cetaceans, owing to the -layers of blubber which float them up, remain often for a -long time with a portion of their bulk out of the water, and -the larger sort often swim long distances with the head and -fore-part out of water. But, even then, the greater part of -the creature’s bulk is under water, and the driving apparatus, -the anterior fins and the mighty tail, are constantly under -water (when the animal is urging its way horizontally, be it -understood). A sea creature, in fact, whatever its nature, -which keeps any considerable volume of its body out of -water constantly, while travelling a long distance, must of -necessity have a much greater volume all the time under -water, and must have its propelling apparatus under water. -Moreover, if the propulsion is not effected by fins, paddles, -a great flat tail, or these combined, but by the undulations -of the animal’s own body, then the part out of water must of -necessity be affected by these undulations, unless it is very -small in volume and length compared with the part under -water. I assert both these points as matters depending on -physical laws, and without fear that the best-informed<span class="pagenum"><a id="Page_217">217</a></span> -zoologist can adduce any instances to the contrary. It is in -fact physically impossible that such instances should exist.</p> - -<p>It would not be saying too much to assert that if the so-called -sea-serpent were really a serpent, its entire length -must be nearer 1000 than 100 feet. This, of course, is -utterly incredible. We are, therefore, forced to the belief -that the creature is not a serpent. If it were a long-necked -reptile, with a concealed body much bulkier than the neck, -the requirements of floatation would be satisfied; if to that -body there were attached powerful paddles, the requirements -of propulsion would be satisfied. The theory, then, suggested, -first by Mr. Newman, later but independently by Mr. -Stirling, and advocated since by several naturalists of repute, -is simply that the so-called sea-serpent is a modern representative -of the long-necked plesiosaurian reptile to which has -been given the name of the <i>enaliosaurus</i>. Creatures of this -kind prevailed in that era when what is called the lias was -formed, a fossiliferous stratum belonging to the secondary or -mesozoic rocks. They are not found in the later or tertiary -rocks, and thereon an argument might be deduced against -their possible existence in the present, or post-tertiary, -period; but, as will presently be shown, this argument is far -from being conclusive. The enaliosaurian reptiles were -“extraordinary,” says Lyell, “for their number, size, and -structure.” Like the ichthyosauri, or fish-lizards, the enaliosauri -(or serpent-turtles, as they might almost be called) -were carnivorous, their skeletons often enclosing the fossilized -remains of half-digested fishes. They had extremely long -necks, with heads very small compared with the body. They -are supposed to have lived chiefly in narrow seas and -estuaries, and to have breathed air like the modern whales -and other aquatic mammals. Some of them were of formidable -dimensions, though none of the skeletons yet discovered -indicate a length of more than 35 feet. It is not, however, -at all likely that the few skeletons known indicate the full -size attained by these creatures. Probably, indeed, we have -the remains of only a few out of many species, and some<span class="pagenum"><a id="Page_218">218</a></span> -species existing in the mesozoic period may have as largely -exceeded those whose skeletons have been found, as the boa-constrictor -exceeds the common ringed snake. It is also -altogether probable that in the struggle for existence during -which the enaliosaurian reptiles have become <em>almost</em> extinct -(according to the hypothesis we are considering), none but -the largest and strongest had any chance, in which case the -present representatives of the family would largely exceed in -bulk their progenitors of the mesozoic period.</p> - -<p>A writer in the <cite>Times</cite> of November 2, 1848, under the -signature F. G. S., pointed out how many of the external -characters of the creature seen from the <i>Dædalus</i> corresponded -with the belief that it was a long-necked plesiosaurus. -“Geologists,” he said, “are agreed in the inference that the -plesiosauri carried their necks, which must have resembled -the bodies of serpents, above the water, while their propulsion -was effected by large paddles working beneath, the -short but stout tail acting the part of a rudder.... In the -letter and drawing of Captain M’Quhæ ... we have ... -the short head, the serpent-like neck, carried several feet -above the water. Even the bristly mane in certain parts -of the back, so unlike anything found in serpents, has its -analogue in the iguana, to which animal the plesiosaurus -has been compared by some geologists. But I would most -of all insist upon the peculiarity of the animal’s progression, -which could only have been effected with the evenness and -at the rate described by an apparatus of fins or paddles, not -possessed by serpents, but existing in the highest perfection -in the plesiosaurus.”</p> - -<p>At this stage a very eminent naturalist entered the field—Professor -Owen. He dwelt first on a certain characteristic -of Captain M’Quhæ’s letter which no student of science -could fail to notice—the definite statement that the creature -<em>was</em> so and so, where a scientific observer would simply -have said that the creature presented such and such characteristics. -“No sooner was the captain’s attention called to -the object,” says Professor Owen, “than ‘it was discovered<span class="pagenum"><a id="Page_219">219</a></span> -to be an enormous serpent,’” though in reality the true -nature of the creature could not be determined even from -the observations made during the whole time that it remained -visible. Taking, however, “the more certain characters,” -the “head with a convex, moderately capacious cranium, -short, obtuse muzzle, gape not extending further than to beneath -the eye, which (the eye) is rather small, round, filling -closely the palpebral aperture” (that is, the eyelids fit -closely<a id="FNanchor_25" href="#Footnote_25" class="fnanchor">25</a>); “colour and surface as stated; nostrils indicated -in the drawing by a crescentic mark at the end of the nose -or muzzle. All these,” proceeds Owen, “are the characters -of the head of a warm-blooded mammal, none of them those -of a cold-blooded reptile or fish. Body long, dark brown, -not undulating, without dorsal or other apparent fins, ‘but -something like the mane of a horse, or rather a bunch of -sea-weed, washed about its back.’” He infers that the -creature had hair, showing only where longest on the back, -and therefore that the animal was not a mammal of the -whale species but rather a great seal. He then shows that -the sea-elephant, or <i>Phoca proboscidea</i>, which attains the -length of from 20 to 30 feet, was the most probable member -of the seal family to be found about 300 miles from the -western shore of the southern end of Africa, in latitude -24° 44´. Such a creature, accidentally carried from its -natural domain by a floating iceberg, would have (after its -iceberg had melted) to urge its way steadily southwards, as -the supposed sea-serpent was doing; and probably the creature -approached the <i>Dædalus</i> to scan her “capabilities as a -resting-place, as it paddled its long, stiff body past the ship.” -“In so doing it would raise a head of the form and colour -described and delineated by Captain M’Quhæ”—its head -only, be it remarked, corresponding with the captain’s description. -The neck also would be of the right diameter.<span class="pagenum"><a id="Page_220">220</a></span> -The thick neck, passing into an inflexible trunk, the longer -and coarser hair on the upper part of which would give rise -to the idea “explained by the similes above cited” (of a -mane or bunch of sea-weed), the paddles would be out of -sight; and the long eddy and wake created by the propelling -action of the tail would account for the idea of a long -serpentine body, at least for this idea occurring to one -“looking at the strange phenomenon with a sea-serpent in his -mind’s eye.” “It is very probable that not one on board -the <i>Dædalus</i> ever before beheld a gigantic seal freely swimming -in the open ocean.” The excitement produced by the -strange spectacle, and the recollection of “old Pontoppidan’s -sea-serpent with the mane,” would suffice, Professor Owen -considered, to account for the metamorphosis of a sea-elephant -into a maned sea-serpent.</p> - -<p>This was not the whole of Professor Owen’s argument; -but it may be well to pause here, to consider the corrections -immediately made by Captain M’Quhæ; it may be noticed, -first, that Professor Owen’s argument seems sufficiently to -dispose of the belief that the creature really was a sea-serpent, -or any cold-blooded reptile. And this view of the -matter has been confirmed by later observations. But few, -I imagine, can readily accept the belief that Captain M’Quhæ -and his officers had mistaken a sea-elephant for a creature -such as they describe and picture. To begin with, although -it might be probable enough that no one on board the -<i>Dædalus</i> had ever seen a gigantic seal freely swimming in -the open ocean—a sight which Professor Owen himself had -certainly never seen—yet we can hardly suppose they would -not have known a sea-elephant under such circumstances. -Even if they had never seen a sea-elephant at all, they would -surely know what such an animal is like. No one could -mistake a sea-elephant for any other living creature, even -though his acquaintance with the animal were limited to -museum specimens or pictures in books. The supposition -that the entire animal, that is, its entire length, should be -mistaken for 30 or 40 feet of the length of a serpentine neck,<span class="pagenum"><a id="Page_221">221</a></span> -seems, in my judgment, as startling as the ingenious theory -thrown out by some naturalists when they first heard of the -giraffe—to the effect that some one of lively imagination -had mistaken the entire body of a short-horned antelope for -the neck of a much larger animal!</p> - -<p>Captain M’Quhæ immediately replied:—“I assert that -neither was it a common seal nor a sea-elephant; its great -length and its totally different physiognomy precluding the -possibility of its being a <i>Phoca</i> of any species. The head -was flat, and not a capacious vaulted cranium; nor had it a -stiff, inflexible trunk—a conclusion to which Professor Owen -has jumped, most certainly not justified by my simple statement, -that ‘no portion of the 60 feet seen by us was used -in propelling it through the water, either by vertical or horizontal -undulation.’” He explained that the calculation of -the creature’s length was made before, not after, the idea -had been entertained that the animal was a serpent, and that -he and his officers were “too well accustomed to judge of -lengths and breadths of objects in the sea to mistake a real -substance and an actual living body, coolly and dispassionately -contemplated, at so short a distance too, for the ‘eddy -caused by the action of the deeply immersed fins and tail of -a rapidly moving, gigantic seal raising its head above the -water,’ as Professor Owen imagines, in quest of its lost iceberg.” -He next disposed of Owen’s assertion that the idea -of clothing the serpent with a mane had been suggested by -old Pontoppidan’s story, simply because he had never seen -Pontoppidan’s account or heard of Pontoppidan’s sea-serpent, -until he had told his own tale in London. Finally, he -added, “I deny the existence of excitement, or the possibility -of optical illusion. I adhere to the statement as to -form, colour, and dimensions, contained in my report to the -Admiralty.”</p> - -<p>A narrative which appeared in the <cite>Times</cite> early in 1849 -must be referred to in this place, as not being readily -explicable by Professor Owen’s hypothesis. It was written by -Mr. R. Davidson, superintending surgeon, Najpore Subsidiary<span class="pagenum"><a id="Page_222">222</a></span> -Force Kamptee, and was to the following effect (I abridge -it considerably):—When at a considerable distance south-west -of the Cape of Good Hope, Mr. Davidson, Captain -Petrie, of the <i>Royal Saxon</i>, a steerage passenger, and the -man at the wheel, saw “an animal of which no more correct -description could be given than that by Captain M’Quhæ. -It passed within 35 yards of the ship, without altering its -course in the least; but as it came right abreast of us it -slowly turned its head towards us.” About one-third of the -upper part of its body was above water, “in nearly its whole -length; and we could see the water curling up on its breast -as it moved along, but by what means it moved we could -not perceive.” They <em>saw this creature in its whole length</em> -with the exception of a small portion of the tail which was -under water; and by comparing its length with that of the -<i>Royal Saxon</i>, 600 feet, when exactly alongside in passing, -they calculated it to be in length as well as in other dimensions -greater than the animal described by Captain M’Quhæ.</p> - -<p>In the year 1852 two statements were made, one by -Captain Steele, 9th Lancers, the other by one of the officers -of the ship <i>Barham</i> (India merchantman), to the effect that -an animal of a serpentine appearance had been seen about -500 yards from that ship (in longitude 40° E. and 37° 16´ S., -that is, east of the south-eastern corner of Africa). “We -saw him,” said the former, “about 16 or 20 feet out of the -water, and he <em>spouted</em> a long way from his head”—that is, -I suppose, he spouted to some distance, not, as the words -really imply, at a part of his neck far removed from the head. -“Down his back he had a crest like a cock’s comb, and was -going very slowly through the water, but left a wake of about -50 or 60 feet, as if dragging a long body after him. The -captain put the ship off her course to run down to him, but -as we approached him he went down. His colour was green -with light spots. He was seen by every one on board.” -The other witness gives a similar account, adding that the -creature kept moving his head up and down, and was -surrounded by hundreds of birds. “We at first thought it<span class="pagenum"><a id="Page_223">223</a></span> -was a dead whale.... When we were within 100 -yards he slowly sank into the depths of the sea; while we -were at dinner he was seen again.” Mr. Alfred Newton, -the well-known naturalist, guarantees his personal acquaintance -with one of the recipients of the letters just quoted -from. But such a guarantee is, of course, no sufficient -guarantee of the authenticity of the narrative. Even if the -narrative be accepted, the case seems a very doubtful one. -The birds form a suspicious element in the story. Why -should birds cluster around a living sea creature? It seems -to me probable that the sea-weed theory, presently to be -noticed, gives the best explanation of this case. Possibly -some great aggregation of sea-weed was there, in which were -entangled divers objects desirable to birds and to fishes. -These last may have dragged the mass under water when -the ship approached, being perhaps more or less entangled -in it—and it floated up again afterwards. The spouting -may have been simply the play of water over the part mistaken -for the head.</p> - -<p>The sea-weed theory of the sea-serpent was broached in -February, 1849, and supported by a narrative not unlike the -last. When the British ship <i>Brazilian</i> was becalmed almost -exactly in the spot where M’Quhæ had seen his monster, -Mr. Herriman, the commander, perceived something right -abeam, about half a mile to the westward, “stretched along -the water to the length of about 25 or 30 feet, and perceptibly -moving from the ship with a steady, sinuous motion. -The head, which seemed to be lifted several feet above the -waters, had something resembling a mane, running down to -the floating portion, and within about 6 feet of the tail it -forked out into a sort of double fin.” Mr. Herriman, his -first mate, Mr. Long, and several of the passengers, after -surveying the object for some time, came to the unanimous -conclusion that it must be the sea-serpent seen by Captain -M’Quhæ. “As the <i>Brazilian</i> was making no headway, Mr. -Herriman, determining to bring all doubts to an issue, had -a boat lowered down, and taking two hands on board,<span class="pagenum"><a id="Page_224">224</a></span> -together with Mr. Boyd, of Peterhead, near Aberdeen, one -of the passengers, who acted as steersman under the direction -of the captain, they approached the monster, Captain Herriman -standing on the bow of the boat, armed with a harpoon -to commence the onslaught. The combat, however, was -not attended with the danger which those on board apprehended; -for on coming close to the object it was found to -be nothing more than an immense piece of sea-weed, -evidently detached from a coral reef and drifting with the -current, which sets constantly to the westward in this latitude, -and which, together with the swell left by the subsidence of -the gale, gave it the sinuous, snake-like motion.”</p> - -<p>A statement was published by Captain Harrington in the -<cite>Times</cite> of February, 1858, to the effect that from his ship -<i>Castilian</i>, then distant ten miles from the north-east end of -St. Helena, he and his officers had seen a huge marine -animal within 20 yards of the ship; that it disappeared for -about half a minute, and then made its appearance in the -same manner again, showing distinctly its neck and head -about 10 or 12 feet out of the water. “Its head was shaped -like a long nun-buoy,” proceeds Captain Harrington, “and -I suppose the diameter to have been 7 or 8 feet in the -largest part, with a kind of scroll, or tuft, of loose skin -encircling it about 2 feet from the top; the water was discoloured -for several hundred feet from its head.... -From what we saw from the deck, we conclude that it must -have been over 200 feet long. The boatswain and several -of the crew who observed it from the top-gallant forecastle,<a id="FNanchor_26" href="#Footnote_26" class="fnanchor">26</a> -(query, cross-trees?) state that it was more than double the -length of the ship, in which case it must have been 500 feet. -Be that as it may, I am convinced that it belonged to the -serpent tribe; it was of a dark colour about the head, and -was covered with several white spots.”</p> - -<p>This immediately called out a statement from Captain F.<span class="pagenum"><a id="Page_225">225</a></span> -Smith, of the ship <i>Pekin</i>, that on December 28, not far from -the place where the <i>Dædalus</i> had encountered the supposed -sea-serpent, he had seen, at a distance of about half a mile, -a creature which was declared by all hands to be the great -sea-serpent, but proved eventually to be a piece of gigantic -sea-weed. “I have no doubt,” he says, that the great sea-serpent -seen from the <i>Dædalus</i> “was a piece of the same -weed.”</p> - -<p>It will have been noticed that the sea-weed sea-serpents, -seen by Captain F. Smith and by Captain Herriman, were -both at a distance of half a mile, at which distance one can -readily understand that a piece of sea-weed might be mistaken -for a living creature. This is rather different from the -case of the <i>Dædalus</i> sea-serpent, which passed so near that -had it been a man of the captain’s acquaintance he could -have recognized that man’s features with the naked eye. -The case, too, of Captain Harrington’s sea-serpent, seen -within 20 yards of the <i>Castilian</i>, can hardly be compared -to those cases in which sea-weed, more than 800 yards from -the ship, was mistaken for a living animal. An officer of the -<i>Dædalus</i> thus disposed of Captain Smith’s imputation:—“The -object seen from the ship was beyond all question a -living animal, moving rapidly through the water against a -cross sea, and within five points of a fresh breeze, with such -velocity that the water was surging against its chest as it -passed along at a rate probably of ten miles per hour. -Captain M’Quhæ’s first impulse was to tack in pursuit, but -he reflected that we could neither lay up for it nor overhaul -it in speed. There was nothing to be done, therefore, but -to observe it as accurately as we could with our glasses as it -came up under our lee quarter and passed away to windward, -being at its nearest position not more than 200 yards -from us; <em>the eye, the mouth, the nostril, the colour, and the -form, all being most distinctly visible to us</em>.... My impression -was that it was rather of a lizard than a serpentine -character, as its movement was steady and uniform, <em>as if -propelled by fins</em>, not by any undulatory power.”</p> - -<p><span class="pagenum"><a id="Page_226">226</a></span> -But all the evidence heretofore obtained respecting the -sea-serpent, although regarded by many naturalists, Gosse, -Newman, Wilson, and others, as demonstrating the existence -of some as yet unclassified monster of the deep, seems altogether -indecisive by comparison with that which has recently -been given by the captain, mates, and crew of the ship -<i>Pauline</i>. In this case, assuredly, we have not to deal with -a mass of sea-weed, the floating trunk of a tree, a sea-elephant -hastening to his home amid the icebergs, or with any of the -other more or less ingenious explanations of observations -previously made. We have either the case of an actual -living animal, monstrous, fierce, and carnivorous, or else -the five men who deposed on oath to the stated facts devised -the story between them, and wilfully perjured themselves for -no conceivable purpose—that, too, not as men have been -known to perjure themselves under the belief that none -could know of their infamy, but with the certainty on the -part of each that four others (any one of whom might one -day shame him and the rest by confessing) knew the real -facts of the case.</p> - -<p>The story of the <i>Pauline</i> sea-serpent ran simply as follows, -as attested at the Liverpool police-court:—“We, the undersigned, -captain, officers, and crew of the bark <i>Pauline</i>, of -London, do solemnly and sincerely declare, that on July 8, -1875, in latitude 5° 13´ S., longitude 35° W., we observed -three large sperm whales, and one of them was gripped -round the body with two turns of what appeared to be a huge -serpent. The head and tail appeared to have a length -beyond the coils of about 30 feet, and its girth 8 or 9 feet. -The serpent whirled its victim round and round for about -fifteen minutes, and then suddenly dragged the whale to the -bottom, head first.—George Drevat, master; Horatio -Thompson, chief mate; John H. Landells, second mate; -William Lewarn, steward; Owen Baker, A.B. Again on the -13th July a similar serpent was seen about 200 yards off, -shooting itself along the surface, head and neck being out of -the water several feet. This was seen only by the captain<span class="pagenum"><a id="Page_227">227</a></span> -and an ordinary seaman.—George Drevat. A few moments -afterwards it was seen elevated some 60 feet perpendicularly -in the air by the chief officer and two seamen, whose signatures -are affixed.—Horatio Thompson, Owen Baker, -William Lewarn.”</p> - -<p>The usual length of the cachalot or sperm whale is about -70 feet, and its girth about 50 feet. If we assign to the -unfortunate whale which was captured on this occasion, a -length of only 50 feet, and a girth of only 35 feet, we should -still have for the entire length of the supposed serpent about -100 feet. This can hardly exceed the truth, since the three -whales are called large sperm whales. With a length of 100 -feet and a girth of about 9 feet, however, a serpent would -have no chance in an attempt to capture a sperm whale 50 -feet long and 35 feet in girth, for the simple reason that the -whale would be a good deal heavier than its opponent. In -a contest in open sea, where one animal seeks to capture -another bodily, weight is all-important. We can hardly -suppose the whale could be so compassed by the coils of -his enemy as to be rendered powerless; in fact, the contest -lasted fifteen minutes, during the whole of which time the -so-called serpent was whirling its victim round, though more -massive than itself, through the water. On the whole, it -seems reasonable to conclude—in fact, the opinion is almost -forced upon us—that besides the serpentine portion of its -bulk, which was revealed to view, the creature, thus whirling -round a large sperm whale, had a massive concealed body, -provided with propelling paddles of enormous power. <em>These</em> -were at work all the time the struggle went on, enabling the -creature to whirl round its enemy easily, whereas a serpentine -form, with two-thirds of its length, at least, coiled close round -another body, would have had no propulsive power left, or -very little, in the remaining 30 feet of its length, including -both the head and tail ends beyond the coils. Such a -creature as an enaliosaurus <em>could</em> no doubt have done what -a serpent of twice the supposed length would have attempted -in vain—viz., dragged down into the depths of the sea the -mighty bulk of a cachalot whale.</p> - -<p><span class="pagenum"><a id="Page_228">228</a></span> -When all the evidence is carefully weighed, we appear -led to the conclusion that at least one large marine animal -exists which has not as yet been classified among the known -species of the present era. It would appear that this -animal has certainly a serpentine neck, and a head small -compared with its body, but large compared with the -diameter of the neck. It is probably an air-breather and -warm-blooded, and certainly carnivorous. Its propulsive -power is great and apparently independent of undulations -of its body, wherefore it presumably has powerful concealed -paddles. All these circumstances correspond with the -belief that it is a modern representative of the long-neck -plesiosaurians of the great secondary or mesozoic era, a -member of that strange family of animals whose figure has -been compared to that which would be formed by drawing a -serpent through the body of a sea-turtle.</p> - -<p>Against this view sundry objections have been raised, -which must now be briefly considered.</p> - -<p>In the first place, Professor Owen pointed out that the -sea-saurians of the secondary period have been replaced in -the tertiary and present seas by the whales and allied races. -No whales are found in the secondary strata, no saurians -in the tertiary. “It seems to me less probable,” he says, -“that no part of the carcase of such reptiles should have -ever been discovered in a recent unfossilized state, than -that men should have been deceived by a cursory view of -a partly submerged and rapidly moving animal which might -only be strange to themselves. In other words, I regard -the negative evidence from the utter absence of any of the -recent remains of great sea-serpents, krakens, or enaliosauria, -as stronger against their actual existence, than the positive -statements which have hitherto weighed with the public -mind in favour of their existence. A larger body of evidence -from eye-witnesses might be got together in proof of -ghosts than of the sea-serpent.”</p> - -<p>To this it has been replied that genera are now known -to exist, as the <i>Chimæra</i>, the long-necked river tortoise, and<span class="pagenum"><a id="Page_229">229</a></span> -the iguana, which are closely related to forms which existed -in the secondary era, while no traces have been found of -them in any of the intermediate or tertiary strata. The -chimæra is a case precisely analogous to the supposed case -of the enaliosaurus, for the chimæra is but rarely seen, like -the supposed enaliosaurus, is found in the same and absent -from the same fossiliferous strata. Agassiz is quoted in the -<cite>Zoologist</cite>, page 2395, as saying that it would be in precise conformity -with analogy that such an animal as the enaliosaurus -should exist in the American seas, as he had found numerous -instances in which the fossil forms of the Old World were -represented by living types in the New. In close conformity -with this opinion is a statement made by Captain -the Hon. George Hope, that when in the British ship <i>Fly</i>, -in the Gulf of California, the sea being perfectly calm and -transparent, he saw at the bottom a large marine animal, -with the head and general figure of an alligator, but the -neck much longer, and with four large paddles instead of -legs. Here, then, unless this officer was altogether deceived, -which seems quite unlikely under the circumstances, -was a veritable enaliosaurus, though of a far smaller species, -probably, than the creature mistaken for a sea-serpent.</p> - -<p>As for the absence of remains, Mr. Darwin has pointed -out that the fossils we possess are but fragments accidentally -preserved by favouring circumstances in an almost total -wreck. We have many instances of existent creatures, even -such as would have a far better chance of floating after -death, and so getting stranded where their bones might be -found, which have left no trace of their existence. A whale -possessing two dorsal fins was said to have been seen by -Smaltz, a Sicilian naturalist; but the statement was rejected, -until a shoal of these whales were seen by two eminent -French zoologists, MM. Quoy and Gaimard. No carcase, -skeleton, or bone of this whale has ever been discovered. -For seventeen hours a ship, in which Mr. Gosse was travelling -to Jamaica, was surrounded by a species of whale -never before noticed—30 feet long, black above and<span class="pagenum"><a id="Page_230">230</a></span> -white beneath, with swimming paws white on the upper -surface. Here, he says, was “a whale of large size, occurring -in great numbers in the North Atlantic, which on no -other occasion has fallen under scientific observation. The -toothless whale of Havre, a species actually inhabiting the -British Channel, is only known from a single specimen -accidentally stranded on the French coast; and another -whale, also British, is known only from a single specimen -cast ashore on the Elgin roast, and there seen and described -by the naturalist Sowerby.</p> - -<p>Dr. Andrew Wilson, in an interesting paper, in which he -maintains that sea-serpent tales are not to be treated with -derision, but are worthy of serious consideration, “supported -as they are by zoological science, and in the actual details -of the case by evidence as trustworthy in many cases as that -received in our courts of law,” expresses the opinion that plesiosauri -and ichthyosauri have been unnecessarily disinterred -to do duty for the sea-serpents. But he offers as an alternative -only the ribbon-fish; and though some of these may -attain enormous dimensions, yet we have seen that some of -the accounts of the supposed sea-serpent, and especially -the latest narrative by the captain and crew of the <i>Pauline</i>, -cannot possibly be explained by any creature so flat and -relatively so feeble as the ribbon-fish.</p> - -<p>On the whole, it appears to me that a very strong case -has been made out for the enaliosaurian, or serpent-turtle, -theory of the so-called sea-serpent.</p> - -<p>One of the ribbon-fish mentioned by Dr. Wilson, which -was captured, and measured more than 60 feet in length, -might however fairly take its place among strange sea creatures. -I scarcely know whether to add to the number a -monstrous animal like a tadpole, or even more perhaps like a -gigantic skate, 200 feet in length, said to have been seen in -the Malacca Straits by Captain Webster and Surgeon Anderson, -of the ship <i>Nestor</i>. Perhaps, indeed, this monster, mistaken -in the first instance for a shoal, but presently found -to be travelling along at the rate of about ten knots an hour,<span class="pagenum"><a id="Page_231">231</a></span> -better deserves to be called a strange sea creature even than -any of those which have been dealt with in the preceding -pages. But the only account I have yet seen of Captain -Webster’s statement, and Mr. Anderson’s corroboration, -appeared in an American newspaper; and though the story -is exceedingly well authenticated if the newspaper account -of the matter is true, it would not be at all a new feature in -American journalism if not only the story itself, but all the -alleged circumstances of its narration, should in the long -run prove to be pure invention.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_232">232</a></span></p> - -<div class="chapter"> -<h2><a id="ON_SOME_MARVELS_IN_TELEGRAPHY"></a><i>ON SOME MARVELS IN TELEGRAPHY.</i></h2> -</div> - -<p class="in0">Within the last few years Electric Telegraphy has received -some developments which seem wonderful even by comparison -with those other wonders which had before been -achieved by this method of communication. In reality, all -the marvels of electric telegraphy are involved, so to speak, -in the great marvel of electricity itself, a phenomenon as yet -utterly beyond the interpretation of physicists, though not -more so than its fellow marvels, light and heat. We may, -indeed, draw a comparison between some of the most -wonderful results which have recently been achieved by the -study of heat and light and those effected in the application -of electricity to telegraphy. It is as startling to those -unfamiliar with the characteristics of light, or rather with -certain peculiarities resulting from these characteristics, to be -told that an astronomer can tell whether there is water in the -air of Mars or Venus, or iron vapour in the atmosphere of -Aldebaran or Betelgeux, as it is to those unfamiliar with the -characteristics of electricity, or with the results obtained in -consequence of these characteristics, to be told that a written -message can be copied by telegraph, a map or diagram -reproduced, or, most wonderful of all, a musical air correctly -repeated, or a verbal message made verbally audible. -Telegraphic marvels such as these bear to the original<span class="pagenum"><a id="Page_233">233</a></span> -marvel of mere telegraphic communication, somewhat the -same relation which the marvels of spectroscopic analysis as -applied to the celestial orbs bear to that older marvel, the -telescopic scrutiny of those bodies. In each case, also, -there lies at the back of all these marvels a greater marvel -yet—electricity in the one case, light in the other.</p> - -<p>I propose in this essay to sketch the principles on which -some of the more recent wonders of telegraphic communication -depend. I do not intend to describe at any length the -actual details or construction of the various instruments -employed. Precisely as the principles of spectroscopic -analysis can be made clear to the general reader without the -examination of the peculiarities of spectroscopic instruments, -so can the methods and principles of telegraphic communication -be understood without examining instrumental details. -In fact, it may be questioned whether general -explanations are not in such cases more useful than more -detailed ones, seeing that these must of necessity be insufficient -for a student who requires to know the subject -practically in all its details, while they deter the general -reader by technicalities in which he cannot be expected to -take any interest. If it be asked, whether I myself, who -undertake to explain the principles of certain methods of -telegraphic communication, have examined <em>practically</em> the -actual instrumental working of these methods, I answer -frankly that I have not done so. As some sort of proof, -however, that without such practical familiarity with working -details the principles of the construction of instruments may -be thoroughly understood, I may remind the reader (see p. <a href="#Page_96">96</a>) -that the first spectroscopic battery I ever looked through—one -in which the dispersive power before obtained in such -instruments had been practically doubled—was of my own -invention, constructed (with a slight mechanical modification) -by Mr. Browning, and applied at once successfully to the -study of the sun by Mr. Huggins, in whose observatory I saw -through this instrument the solar spectrum extended to a -length which, could it all have been seen at once, would have<span class="pagenum"><a id="Page_234">234</a></span> -equalled many feet.<a id="FNanchor_27" href="#Footnote_27" class="fnanchor">27</a> On the other hand, it is possible to -have a considerable practical experience of scientific instruments -without sound knowledge of the principles of their -construction; insomuch that instances have been known in -which men who have effected important discoveries by the -use of some scientific instrument, have afterwards obtained -their first clear conception of the principles of its construction -from a popular description.</p> - -<p>It may be well to consider, though briefly, some of the -methods of communication which were employed before -the electric telegraph was invented. Some of the methods -of electric telegraphy have their antitypes, so to speak, in -methods of telegraphy used ages before the application of -electricity. The earliest employment of telegraphy was probably -in signalling the approach of invading armies by -beacon fires. The use of this method must have been well -known in the time of Jeremiah, since he warns the Benjamites -“to set up a sign of fire in Beth-haccerem,” because -“evil appeareth out of the north and great destruction.” -Later, instead of the simple beacon fire, combinations were -used. Thus, by an Act of the Scottish Parliament in 1455, -the blazing of one bale indicated the probable approach -of the English, two bales that they were coming indeed, -and four bales blazing beside each other that they were in -great force. The smoke of beacon fires served as signals -by day, but not so effectively, except under very favourable -atmospheric conditions.</p> - -<p>Torches held in the hand, waved, depressed, and so -forth, were anciently used in military signalling at night; -while in the day-time boards of various figures in different -positions indicated either different messages or different -letters, as might be pre-arranged.</p> - -<p>Hooke communicated to the Royal Society in 1684 a -paper describing a method of “communicating one’s mind<span class="pagenum"><a id="Page_235">235</a></span> -at great distances.” The letters were represented by various -combinations of straight lines, which might be agreed upon -previously if secrecy were desired, otherwise the same forms -might represent constantly the same letters. With four -straight planks any letter of this alphabet could be formed -as wanted, and being then run out on a framework (resembling -a gallows in Hooke’s picture), could be seen from a -distant station. Two curved beams, combined in various -ways, served for arbitrary signals.</p> - -<p>Chappe, in 1793, devised an improvement on this in -what was called the T telegraph. An upright post supported -a cross-bar (the top of the T), at each end of which -were the short dependent beams, making the figure a complete -Roman capital T. The horizontal bar as first used -could be worked by ropes within the telegraph-house, so as -to be inclined either to right or left. It thus had three -positions. Each dependent beam could be worked (also -from within the house) so as to turn upwards, horizontally, -or downwards (regarding the top bar of the T as horizontal), -thus having also three positions. It is easily seen that, -since each position of one short beam could be combined -with each position of the other, the two together would -present three times three arrangements, or nine in all; and -as these nine could be given with the cross-bar in any one -of its three positions, there were in all twenty-seven possible -positions. M. Chappe used an alphabet of only sixteen -letters, so that all messages could readily be communicated -by this telegraph. For shorter distances, indeed, and in all -later uses of Chappe’s telegraph, the short beams could be -used in intermediate positions, by which 256 different signals -could be formed. Such telegraphs were employed on a -line beginning at the Louvre and proceeding by Montmartre -to Lisle, by which communications were conveyed from the -Committee of Public Welfare to the armies in the Low -Countries. Telescopes were used at each station. Barrère -stated, in an address to the Convention on August 17, 1794, -that the news of the recapture of Lisle had been sent by<span class="pagenum"><a id="Page_236">236</a></span> -this line of communication to Paris in one hour after the -French troops had entered that city. Thus the message -was conveyed at the rate of more than 120 miles per hour.</p> - -<p>Various other devices were suggested and employed -during the first half of the present century. The semaphores -still used in railway signalling illustrate the general -form which most of these methods assumed. An upright, -with two arms, each capable of assuming six distinct positions -(excluding the upright position), would give forty-eight -different signals; thus each would give six signals alone, -or twelve for the pair, and each of the six signals of one -combined with each of the six signals of the other, would -give thirty-six signals, making forty-eight in all. This number -suffices to express the letters of the alphabet (twenty-five -only are needed), the Arabic numerals, and thirteen -arbitrary signals.</p> - -<p>The progress of improvement in such methods of signalling -promised to be rapid, before the invention of the -electric telegraph, or rather, before it was shown how the -principle of the electric telegraph could be put practically -into operation. We have seen that they were capable of -transmitting messages with considerable rapidity, more than -twice as fast as we could now send a written message by -express train. But they were rough and imperfect. They -were all, also, exposed to one serious defect. In thick -weather they became useless. Sometimes, at the very time -when it was most important that messages should be quickly -transmitted, fog interrupted the signalling. Sir J. Barrow -relates that during the Peninsular War grave anxiety was -occasioned for several hours by the interruption of a message -from Plymouth, really intended to convey news of a -victory. The words transmitted were, “Wellington defeated;” -the message of which these words formed the -beginning was: “Wellington defeated the French at,” etc. -As Barrow remarks, if the message had run, “French defeated -at,” etc., the interruption of the message would have -been of less consequence.</p> - -<p><span class="pagenum"><a id="Page_237">237</a></span> -Although the employment of electricity as a means of -communicating at a distance was suggested before the end -of the last century, in fact, so far back as 1774, the idea -has only been worked out during the last forty-two years. It -is curious indeed to note that until the middle of the present -century the word “telegraph,” which is now always understood -as equivalent to electric telegraph, unless the contrary -is expressed, was commonly understood to refer to semaphore -signalling,<a id="FNanchor_28" href="#Footnote_28" class="fnanchor">28</a> unless the word “electric” were added.</p> - -<p>The general principle underlying all systems of telegraphic -communication by electricity is very commonly -misunderstood. The idea seems to prevail that electricity -can be sent out along a wire to any place where some suitable -arrangement has been made to receive it. In one sense -this is correct. But the fact that the electricity has to make -a circuit, returning to the place from which it is transmitted, -seems not generally understood. Yet, unless this is understood, -the principle, even the possibility, of electric communication -is not recognized.</p> - -<p>Let us, at the outset, clearly understand the nature of -electric communication.</p> - -<p>In a variety of ways, a certain property called electricity -can be excited in all bodies, but more readily in some than -in others. This property presents itself in two forms, which -are called positive and negative electricity, words which we -may conveniently use, but which must not be regarded as -representing any real knowledge of the distinction between -these two kinds of electricity. In fact, let it be remembered -throughout, that we do not in the least know what electricity<span class="pagenum"><a id="Page_238">238</a></span> -is; we only know certain of the phenomena which -it produces. Any body which has become charged with -electricity, either positive or negative, will part with its -charge to bodies in a neutral condition, or charged with the -opposite electricity (negative or positive). But the transference -is made much more readily to some substances than -to others—so slowly, indeed, to some, that in ordinary -experiments the transference may be regarded as not taking -place at all. Substances of the former kind are called good -conductors of electricity; those which receive the transfer -of electricity less readily are said to be bad conductors; -and those which scarcely receive it at all are called insulating -substances. The reader must not confound the -quality I am here speaking of with readiness to become -charged with electricity. On the contrary, the bodies which -most freely receive and transmit electricity are least readily -charged with electricity, while insulating substances are -readily electrified. Glass is an insulator, but if glass is -briskly rubbed with silk it becomes charged (or rather, the -part rubbed becomes charged) with positive electricity, -formerly called <em>vitreous</em> electricity for this reason; and -again, if wax or resin, which are both good insulators, be -rubbed with cloth or flannel, the part rubbed becomes -charged with negative, formerly called <em>resinous</em>, electricity.</p> - -<p>Electricity, then, positive or negative, however generated, -passes freely along conducting substances, but is stopped -by an insulating body, just as light passes through transparent -substances, but is stopped by an opaque body. -Moreover, electricity may be made to pass to any distance -along conducting bodies suitably insulated. Thus, it might -seem that we have here the problem of distant communication -solved. In fact, the first suggestion of the use of electricity -in telegraphy was based on this property. When a -charge of electricity has been obtained by the use of an -ordinary electrical machine, this charge can be drawn off at -a distant point, if a conducting channel properly insulated -connects that point with the bodies (of whatever nature)<span class="pagenum"><a id="Page_239">239</a></span> -which have been charged with electricity. In 1747, Dr. -Watson exhibited electrical effects from the discharges of -Leyden jars (vessels suitably constructed to receive and -retain electricity) at a distance of two miles from the electrical -machine. In 1774, Le Sage proposed that by means -of wires the electricity developed by an electrical machine -should be transmitted by insulated wires to a point where -an electroscope, or instrument for indicating the presence of -electricity, should, by its movements, mark the letters of the -alphabet, one wire being provided for each letter. In 1798 -Béthencourt repeated Watson’s experiment, increasing the distance -to twenty-seven miles, the extremities of his line of communication -being at Madrid and Aranjuez. (Guillemin, by -the way, in his “Applications of the Physical Forces,” passes -over Watson’s experiment; in fact, throughout his chapters -on the electric telegraph, the steam-engine, and other subjects, -he seems desirous of conveying as far as possible the -impression that all the great advances of modern science -had their origin in Paris and its neighbourhood.)</p> - -<p>From Watson’s time until 1823 attempts were made in -this country and on the Continent to make the electrical -machine serve as the means of telegraphic communication. -All the familiar phenomena of the lecture-room have been -suggested as signals. The motion of pith balls, the electric -spark, the perforation of paper by the spark, the discharge of -sparks on a fulminating pane (a glass sheet on which pieces -of tinfoil are suitably arranged, so that sparks passing from -one to another form various figures or devices), and other -phenomena, were proposed and employed experimentally. -But practically these methods were not effectual. The -familiar phenomenon of the electric spark explains the cause -of failure. The spark indicates the passage of electricity -across an insulating medium—dry air—when a good conductor -approaches within a certain distance of the charged -body. The greater the charge of electricity, the greater is -the distance over which the electricity will thus make its -escape. Insulation, then, for many miles of wire, and still<span class="pagenum"><a id="Page_240">240</a></span> -more for a complete system of communication such as we -now have, was hopeless, so long as frictional electricity was -employed, or considerable electrical intensity required.</p> - -<p>We have now to consider how galvanic electricity, discovered -in 1790, was rendered available for telegraphic -communication. In the first place, let us consider what -galvanic or voltaic electricity is.</p> - -<p>I have said that electricity can be generated in many -ways. It may be said, indeed, that every change in the -condition of a substance, whether from mechanical causes, -as, for instance, a blow, a series of small blows, friction, and -so forth, or from change of temperature, moisture, and the -like, or from the action of light, or from chemical processes, -results in the development of more or less electricity.</p> - -<p>When a plate of metal is placed in a vessel containing -some acid (diluted) which acts chemically on the metal, this -action generates negative electricity, which passes away as -it is generated. But if a plate of a different metal, either -not chemically affected by the acid or less affected than the -former, be placed in the dilute acid, the two plates being -only partially immersed and not in contact, then, when a -wire is carried from one plate to the other, the excess of -positive electricity in the plate least affected by the acid is -conveyed to the other, or, in effect, discharged; the chemical -action, however, continues, or rather is markedly increased, -fresh electricity is generated, and the excess of positive -electricity in the plate least affected is constantly discharged. -Thus, along the wire connecting the two metals a current of -electricity passes from the metal least affected to the metal -most affected; a current of negative electricity passes in a -contrary direction in the dilute acid.</p> - -<p>I have spoken here of currents passing along the wire -and in the acid, and shall have occasion hereafter to speak -of the plate of metal least affected as the positive pole, this -plate being regarded, in this case, as a source whence a -current of positive electricity flows along the wire connection -to the other plate, which is called the negative pole. But I<span class="pagenum"><a id="Page_241">241</a></span> -must remind the reader that this is only a convenient way -of expressing the fact that the wire assumes a certain condition -when it connects two such plates, and is capable of -producing certain effects. Whether in reality any process is -taking place which can be justly compared to the flow of a -current one way or the other, or whether a negative current -flows along the circuit one way, while the positive current -flows the other way, are questions still unanswered. We -need not here enter into them, however. In fact, very little -is known about these points. Nor need we consider here -the various ways in which many pairs of plates such as I -have described can be combined in many vessels of dilute -acid to strengthen the current. Let it simply be noted that -such a combination is called a battery; that when the extreme -plates of opposite kinds are connected by a wire, a -current of electricity passes along the wire from the extreme -plate of that metal which is least affected, forming the positive -pole, to the other extreme plate of that metal which is -most affected and forms the negative pole. The metals -commonly employed are zinc and copper, the former being -the one most affected by the action of the dilute acid, usually -sulphuric acid. But it must here be mentioned that the -chemical process, affecting both metals, but one chiefly, -would soon render a battery of the kind described useless; -wherefore arrangements are made in various ways for maintaining -the efficiency of the dilute acid and of the metallic -plates, especially the copper: for the action of the acid on -the zinc tends, otherwise, to form on the copper a deposit of -zinc. I need not describe the various arrangements for -forming what are called constant batteries, as Daniell’s, -Grove’s, Bunsen’s, and others. Let it be understood that, -instead of a current which would rapidly grow weaker and -weaker, these batteries give a steady current for a considerable -time. Without this, as will presently be seen, telegraphic -communication would be impossible.</p> - -<p>We have, then, in a galvanic battery a steady source of -electricity. This electricity is of low intensity, incompetent<span class="pagenum"><a id="Page_242">242</a></span> -to produce the more striking phenomena of frictional electricity. -Let us, however, consider how it would operate at -a distance.</p> - -<p>The current will pass along any length of conducting -substance properly insulated. Suppose, then, an insulated -wire passes from the positive pole of a battery at a station -<span class="smcap smaller">A</span> to a station <span class="smcap smaller">B</span>, and thence back to the negative pole at -the station <span class="smcap smaller">A</span>. Then the current passes along it, and this -can be indicated at <span class="smcap smaller">B</span> by some action such as electricity of -low intensity can produce. If now the continuity of the -wire be interrupted close by the positive pole at <span class="smcap smaller">A</span>, the current -ceases and the action is no longer produced. The -observer at <span class="smcap smaller">B</span> knows then that the continuity of the wire has -been interrupted; he has been, in fact, signalled to that -effect.</p> - -<p>But, as I have said, the electrical phenomena which can -be produced by the current along a wire connecting the -positive and negative poles of a galvanic battery are not -striking. They do not afford effective signals when the -distance traversed is very great and the battery not exceptionally -strong. Thus, at first, galvanic electricity was not -more successful in practice than frictional electricity.</p> - -<p>It was not until the effect of the galvanic current on the -magnetic needle had been discovered that electricity became -practically available in telegraphy.</p> - -<p>Oersted discovered in 1820 that a magnetic needle poised -horizontally is deflected when the galvanic current passes -above it (parallel to the needle’s length) or below it. If the -current passes above it, the north end of the needle turns -towards the east when the current travels from north to -south, but towards the west when the current travels from -south to north; on the other hand, if the current passes -below the needle, the north end turns towards the west when -the current travels from south to north, and towards the east -when the current travels from north to south. The deflection -will be greater or less according to the power of the current. It -would be very slight indeed in the case of a needle, however<span class="pagenum"><a id="Page_243">243</a></span> -delicately poised, above or below which passed a wire conveying -a galvanic current from a distant station. But the -effect can be intensified, as follows:—</p> - -<div id="ip_243" class="figcenter" style="max-width: 25.9375em;"> - <img src="images/i_243.jpg" width="415" height="77" alt="" /> - <div class="caption"><span class="smcap">Fig. 1.</span></div></div> - -<p>Suppose <i>a b c d e f</i> to be a part of the wire from <span class="smcap smaller">A</span> to <span class="smcap smaller">B</span>, -passing above a delicately poised magnetic needle <span class="smcap">N S</span>, along -<i>a b</i> and then below the needle along <i>c d</i>, and then above -again along <i>e f</i> and so to the station <span class="smcap smaller">B</span>. Let a current -traverse the wire in the direction shown by the arrows. Then -<span class="smcap smaller">N</span>, the north end of the needle, is deflected towards the east -by the current passing along <i>a b</i>. But it is also deflected -to the east by the current passing along <i>c d</i>; for this -produces a deflection the reverse of that which would be -produced by a current in the same direction above the -needle—that is, in direction <i>b a</i>, and therefore the same as -that produced by the current along <i>a b</i>. The current along -<i>e f</i> also, of course, produces a deflection of the end <span class="smcap smaller">N</span> towards -the east. All three parts, then, <i>a b</i>, <i>c d</i>, <i>e f</i>, conspire -to increase the deflection of the end <span class="smcap smaller">N</span> towards the east. -If the wire were twisted once again round <span class="smcap">N S</span>, the deflection -would be further increased; and finally, if the wire be coiled -in the way shown in <a href="#ip_243">Fig. 1</a>, but with a great number of -coils, the deflection of the north end towards the east, -almost imperceptible without such coils, will become sufficiently -obvious. If the direction of the current be changed, -the end <span class="smcap smaller">N</span> will be correspondingly deflected towards the -west.</p> - -<p>The needle need not be suspended horizontally. If it -hang vertically, that is, turn freely on a horizontal axis, and -the coil be carried round it as above described, the deflection -of the upper end will be to the right or to the left, -according to the direction of the current. The needle -actually seen, moreover, is not the one acted upon by the<span class="pagenum"><a id="Page_244">244</a></span> -current. This needle is inside the coil; the needle seen turns -on the same axis, which projects through the coil.</p> - -<p>If, then, the observer at the station <span class="smcap smaller">B</span> have a magnetic -needle suitably suspended, round which the wire from the -battery at <span class="smcap smaller">A</span> has been coiled, he can tell by the movement of -the needle whether a current is passing along the wire in -one direction or in the other; while if the needle is at rest he -knows that no current is passing.</p> - -<div id="ip_244" class="figcenter" style="max-width: 30.1875em;"> - <img src="images/i_244.jpg" width="483" height="129" alt="" /> - <div class="caption"><span class="smcap">Fig. 2.</span></div></div> - -<div id="ip_244b" class="figcenter" style="max-width: 30.1875em;"> - <img src="images/i_244a.jpg" width="483" height="127" alt="" /> - <div class="caption"><span class="smcap">Fig. 3.</span></div></div> - -<p>Now suppose that <span class="smcap smaller">P</span> and <span class="smcap smaller">N</span>, <a href="#ip_244">Fig. 2</a>, are the positive and -negative poles of a galvanic battery at <span class="smcap smaller">A</span>, and that a wire passes -from <span class="smcap smaller">P</span> to the station <span class="smcap smaller">B</span>, where it is coiled round a needle -suspended vertically at <i>n</i>, and thence passes to the negative -pole <span class="smcap smaller">N</span>. Let the wire be interrupted at <i>a b</i> and also at <i>c d</i>. -Then no current passes along the wire, and the needle <i>n</i> -remains at rest in a vertical position. Now suppose the -points <i>a b</i> connected by the wire <i>a b</i>, and at the same moment -the points <i>c d</i> connected by the wire <i>c d</i>, then a current -flows along <span class="smcap smaller">P</span> <i>a b</i> to <span class="smcap smaller">B</span>, as shown in <a href="#ip_244">Fig. 2</a>, circuiting the coil -round the needle <i>n</i> and returning by <i>d c</i> to <span class="smcap smaller">N</span>. The upper -end of the needle is deflected to the right while this current -continues to flow; returning to rest when the connection is -broken at <i>a b</i> and <i>c d</i>. Next, let <i>c b</i> and <i>a d</i> be simultaneously<span class="pagenum"><a id="Page_245">245</a></span> -connected as shown by the cross-lines in <a href="#ip_244b">Fig. 3</a>. (It -will be understood that <i>a d</i> and <i>b c</i> do not touch each other -where they cross.) The current will now flow from <span class="smcap smaller">P</span> along -<i>a d</i> to <span class="smcap smaller">B</span>, circuiting round the needle <i>n</i> in a contrary direction -to that in which it flowed in the former case, returning by -<i>b c</i> to <span class="smcap smaller">N</span>. The upper end of the needle is deflected then to -the left while the current continues to flow along this course.</p> - -<p>I need not here describe the mechanical devices by -which the connection at <i>a b</i> and <i>c d</i> can be instantly changed -so that the current may flow either along <i>a b</i> and <i>d c</i>, as in -<a href="#ip_244">Fig. 2</a>, circuiting the needle in one direction, or along <i>a d</i> -and <i>b c</i>, as in <a href="#ip_244b">Fig. 3</a>, circuiting the needle in the other direction. -As I said at the outset, this paper is not intended to -deal with details of construction, only to describe the general -principles of telegraphic communication, and especially those -points which have to be explained in order that recent inventions -may be understood. The reader will see that nothing -can be easier than so to arrange matters that, by turning a -handle, either (1), <i>a b</i> and <i>c d</i> may be connected, or, (2), <i>a d</i> -and <i>c b</i>, or, (3), both lines of communication interrupted. -The mechanism for effecting this is called a <em>commutator</em>.</p> - -<p>Two points remain, however, to be explained: First, <span class="smcap smaller">A</span> -must be a receiving station as well as a transmitting station; -secondly, the wire connecting <span class="smcap smaller">B</span> with <span class="smcap smaller">N</span>, in Figs. 2 and 3, can -be dispensed with, for it is found that if at <span class="smcap smaller">B</span> the wire is -carried down to a large metal plate placed some depth -underground, while the wire at <i>c</i> is carried down to another -plate similarly buried underground, the circuit is completed -even better than along such a return wire as is shown in the -figures. The earth either acts the part of a return wire, or -else, by continually carrying off the electricity, allows the -current to flow continuously along the single wire. We -may compare the current carried along the complete wire -circuit, to water circulating in a pipe extending continuously -from a reservoir to a distance and back again to -the reservoir. Water sucked up continuously at one end -could be carried through the pipe so long as it was continuously<span class="pagenum"><a id="Page_246">246</a></span> -returned to the reservoir at the other; but it could -equally be carried through a pipe extending from that reservoir -to some place where it could communicate with the -open sea—the reservoir itself communicating with the open -sea—an arrangement corresponding to that by which the -return wire is dispensed with, and the current from the wire -received into the earth.</p> - -<p>The discovery that the return wire may be dispensed -with was made by Steinheil in 1837.</p> - -<p>The actual arrangement, then, is in essentials that represented -in <a href="#ip_246">Fig. 4</a>.</p> - -<div id="ip_246" class="figcenter" style="max-width: 35.0625em;"> - <img src="images/i_246.jpg" width="561" height="206" alt="" /> - <div class="caption"><span class="smcap">Fig. 4.</span></div></div> - -<p><span class="smcap smaller">A</span> and <span class="smcap smaller">B</span> are the two stations; <span class="smcap">P N</span> is the battery at <span class="smcap smaller">A</span>, <span class="smcap">P´ N´</span> -the battery at <span class="smcap smaller">B</span>; <span class="smcap">P´ P´</span> are the positive poles, <span class="smcap">N´ N´</span>, the negative -poles. At <i>n</i> is the needle of station <span class="smcap smaller">A</span>, at <i>n´</i> the needle of -station <span class="smcap smaller">B</span>. When the handle of the commutator is in its -mean position—which is supposed to be the case at station -<span class="smcap smaller">B</span>—the points <i>b´ d´</i> are connected with each other, but -neither with <i>a´</i> nor <i>c´</i>; no current, then, passes from <span class="smcap smaller">B</span> to <span class="smcap smaller">A</span>, -but station <span class="smcap smaller">B</span> is in a condition to receive messages. (If <i>b´</i> -and <i>d´</i> were not connected, of course no messages could be -received, since the current from <span class="smcap smaller">A</span> would be stopped at <i>b´</i>—which -does not mean that it would pass round <i>n´</i> to <i>b´</i>, but -that, the passage being stopped at <i>b´</i>, the current would not -flow at all.) When (the commutator at <span class="smcap smaller">B</span> being in its mean -position, or <i>d´ b´</i> connected, and communication with <i>c´</i> and -<i>a´</i> interrupted) the handle of the commutator at <span class="smcap smaller">A</span> is turned<span class="pagenum"><a id="Page_247">247</a></span> -from its mean position in <em>one</em> direction, <i>a</i> and <i>b</i> are connected, -as are <i>c</i> and <i>d</i>—as shown in the figure—while the connection -between <i>b</i> and <i>d</i> is broken. Thus the current passes from <span class="smcap smaller">P</span> -by <i>a</i> and <i>b</i>, round the needle <i>n</i>; thence to station <span class="smcap smaller">B</span>, round -needle <i>n´</i>, and by <i>b´</i> and <i>d´</i>, to the earth plate <span class="smcap">G´</span>; and so -along the earth to <span class="smcap smaller">G</span>, and by <i>d c</i>, to the negative pole <span class="smcap smaller">N</span>. -The upper end of the needle of both stations is deflected to -the right by the passage of the current in this direction. -When the handle of the commutator at <span class="smcap smaller">A</span> is turned in the -other direction, <i>b</i> and <i>c</i> are connected, as also <i>a</i> and <i>d</i>; the -current from <span class="smcap smaller">P</span> passes along <i>a d</i> to the ground plate <span class="smcap smaller">G</span>, thence -to <span class="smcap">G´</span>, along <i>d´ b´</i>, round the needle <i>n´</i>, back by the wire to -the station <span class="smcap smaller">A</span>, where, after circuiting the needle <i>n</i> in the same -direction as the needle <i>n´</i>, it travels by <i>b</i> and <i>c</i> to the negative -pole <span class="smcap smaller">N</span>. The upper end of the needle, at both stations, -is deflected to the left by the passage of the current in this -direction.</p> - -<p>It is easily seen that, with two wires and one battery, -two needles can be worked at both stations, either one -moving alone, or the other alone, or both together; but for -the two to move differently, two batteries must be used. -The systems by which either the movements of a single -needle, or of a pair of needles, may be made to indicate the -various letters of the alphabet, numerals, and so on, need -not here be described. They are of course altogether -arbitrary, except only that the more frequent occurrence of -certain letters, as <i>e</i>, <i>t</i>, <i>a</i>, renders it desirable that these -should be represented by the simplest symbols (as by a -single deflection to right or left), while letters which occur -seldom may require several deflections.</p> - -<p>One of the inventions to which the title of this paper -relates can now be understood.</p> - -<div class="figdummyl"> </div> -<div id="ip_247" class="figleft" style="max-width: 12em;"> - <img src="images/i_248.jpg" width="192" height="185" class="dummy" alt="" /> - <div class="caption"><span class="smcap">Fig. 5.</span></div></div> - -<p>In the arrangement described, when a message is transmitted, -the needle of the sender vibrates synchronously with -the needle at the station to which the message is sent. -Therefore, till that message is finished, none can be received -at the transmitting station. In what is called duplex telegraphy,<span class="pagenum"><a id="Page_248">248</a></span> -this state of things is altered, the needle at the -sending station being left unaffected by the transmitted -current, so as to be able to receive messages, and in self-recording -systems to record them. This is done by dividing -the current from the battery into two parts of equal -efficiency, acting on the needle at the transmitting station in -contrary directions, so that this needle remains unaffected, -and ready to indicate signals from -the distant station. The principle -of this arrangement is indicated in -<a href="#ip_247">Fig. 5</a>. Here <i>a b n</i> represents the -main wire of communication with -the distant station, coiled round -the needle of the transmitting -station in one direction; the dotted -lines indicate a finer short wire, -coiled round the needle in a contrary -direction. When a message -is transmitted, the current along the main wire tends to -deflect the needle at <i>n</i> in one direction, while the current -along the auxiliary wire tends to deflect it in the other -direction. If the thickness and length of the short wire are -such as to make these two tendencies equal, the needle -remains at rest, while a message is transmitted to the distant -station along the main wire. In this state of things, if a -current is sent from the distant station along the wire in the -direction indicated by the dotted arrow, this current also -circuits the auxiliary wire, but in the direction indicated by -the arrows on the dotted curve, which is the same direction -in which it circuits the main wire. Thus the needle is -deflected, and a signal received. When the direction of the -chief current at the transmitting station is reversed, so also -is the direction of the artificial current, so that again the -needle is balanced. Similarly, if the direction of the current -from the distant station is reversed, so also is the direction -in which this current traverses the auxiliary wire, so that -again both effects conspire to deflect the needle.</p> - -<p><span class="pagenum"><a id="Page_249">249</a></span> -There is, however, another way in which an auxiliary wire -may be made to work. It may be so arranged that, when a -message is transmitted, the divided current flowing equally -in opposite directions, the instrument at the sending station -is not affected; but that when the operator at the distant -station sends a current along the main wire, this neutralizes -the current coming towards him, which current had before -balanced the artificial current. The latter, being no longer -counterbalanced, deflects the needle; so that, in point of -fact, by this arrangement, the signal received at a station is -produced by the artificial current at that station, though of -course the real cause of the signal is the transmission of the -neutralizing current from the distant station.</p> - -<p>The great value of duplex telegraphy is manifest. Not -only can messages be sent simultaneously in both directions -along the wire—a circumstance which of itself would double -the work which the wire is capable of doing—but all loss -of time in arranging about the order of outward and homeward -messages is prevented. The saving of time is especially -important on long lines, and in submarine telegraphy. -It is also here that the chief difficulties of duplex telegraphy -have been encountered. The chief current and the artificial -current must exactly balance each other. For this purpose -the flow along each must be equal. In passing through -the long wire, the current has to encounter a greater resistance -than in traversing the short wire; to compensate -for this difference, the short wire must be much finer than -the long one. The longer the main wire, the more delicate -is the task of effecting an exact balance. But in the case -of submarine wires, another and a much more serious difficulty -has to be overcome. A land wire is well insulated. -A submarine wire is separated by but a relatively moderate -thickness of gutta-percha from water, an excellent conductor, -communicating directly with the earth, and is, moreover, -surrounded by a protecting sheathing of iron wires, -laid spirally round the core, within which lies the copper -conductor. Such a cable, as Faraday long since showed,<span class="pagenum"><a id="Page_250">250</a></span> -acts precisely as an enormous Leyden jar; or rather, Faraday -showed that such a cable, without the wire sheathing, -would act when submerged as a Leyden jar, the conducting -wire acting as the interior metallic coating of such a jar, -the gutta-percha as the glass of the jar (the insulating -medium), and the water acting as the exterior metallic -coating. Wheatstone showed further that such a cable, -with a wire sheathing, would act as a Leyden jar, even -though not submerged, the metal sheathing taking the part -of the exterior coating of the jar. Now, regarding the cable -thus as a condenser, we see that the transmission of a -current along it may in effect be compared with the passage -of a fluid along a pipe of considerable capacity, into which -and from which it is conveyed by pipes of small capacity. -There will be a retardation of the flow of water corresponding -to the time necessary to fill up the large part of the -pipe; the water may indeed begin to flow through as -quickly as though there were no enlargement of the bore of -the pipe, but the full flow from the further end will be -delayed. Just so it is with a current transmitted through a -submarine cable. The current travels instantly (or with the -velocity of freest electrical transmission) along the entire -line; but it does not attain a sufficient intensity to be -recognized for some time, nor its full intensity till a still -longer interval has elapsed. The more delicate the means -of recognizing its flow, the more quickly is the signal received. -The time intervals in question are not, indeed, -very great. With Thomson’s mirror galvanometer, in which -the slightest motion of the needle is indicated by a beam -of light (reflected from a small mirror moving with the -needle), the Atlantic cable conveys its signal from Valentia -to Newfoundland in about one second, while with the less -sensitive galvanometer before used the time would be rather -more than two seconds.</p> - -<p>Now, in duplex telegraphy the artificial current must be -equal to the chief current in intensity all the time; so that, -since in submarine telegraphy the current rises gradually to<span class="pagenum"><a id="Page_251">251</a></span> -its full strength and as gradually subsides, the artificial -current must do the same. Reverting to the illustration -derived from the flow of water, if we had a small pipe the -rapid flow through which was to carry as much water one -way as the slow flow through a large pipe was to carry water -the other way, then if the large pipe had a widening along -one part of its long course the short pipe would require -to have a similar widening along the corresponding part of -its short course. And to make the illustration perfect, the -widenings along the large pipe should be unequal in different -parts of the pipe’s length; for the capacity of a submarine -cable, regarded as a condenser, is different along different -parts of its length. What is wanted, then, for a satisfactory -system of duplex telegraphy in the case of submarine cables, -is an artificial circuit which shall not only correspond as -a whole to the long circuit, but shall reproduce at the -corresponding parts of its own length all the varieties of -capacity existing along various parts of the length of the -submarine cable.</p> - -<p>Several attempts have been made by electricians to -accomplish this result. Let it be noticed that two points -have to be considered: the intensity of the current’s action, -which depends on the resistance it has to overcome in -traversing the circuit; and the velocity of transmission, depending -on the capacity of various parts of the circuit to -condense or collect electricity. Varley, Stearn, and others -have endeavoured by various combinations of condensers -with resistance coils to meet these two requisites. But the -action of artificial circuits thus arranged was not sufficiently -uniform. Recently Mr. J. Muirhead, jun., has met the -difficulty in the following way (I follow partially the account -given in the <cite>Times</cite> of February 3, 1877, which the reader will -now have no difficulty in understanding):—He has formed -his second circuit by sheets of paper prepared with paraffin, -and having upon one side a strip of tinfoil, wound to and -fro to represent resistance. Through this the artificial -current is conducted. On the other side is a sheet of tinfoil<span class="pagenum"><a id="Page_252">252</a></span> -to represent the sheathing,<a id="FNanchor_29" href="#Footnote_29" class="fnanchor">29</a> and to correspond to the -capacity of the wire. Each sheet of paper thus prepared -may be made to represent precisely a given length of cable, -having enough tinfoil on one side to furnish the resistance, -and on the other to furnish the capacity. A sufficient -number of such sheets would exactly represent the cable, -and thus the artificial or non-signalling part of the current -would be precisely equivalent to the signalling part, so far -as its action on the needle at the transmitting station was -concerned. “The new plan was first tried on a working -scale,” says the <cite>Times</cite>, “on the line between Marseilles and -Bona; but it has since been brought into operation from -Marseilles to Malta, from Suez to Aden, and lastly, from -Aden to Bombay. On a recent occasion when there was -a break-down upon the Indo-European line, the duplex -system rendered essential service, and maintained telegraphic -communication which would otherwise have been most -seriously interfered with.” The invention, we may well -believe, “cannot fail to be highly profitable to the proprietors -of submarine cables,” or to bring about “before -long a material reduction in the cost of messages from -places beyond the seas.”</p> - -<div class="tb">* <span class="in2">* </span><span class="in2">* </span><span class="in2">* </span><span class="in2">*</span></div> - -<p>The next marvel of telegraphy to be described is the -transmission of actual facsimiles of writings or drawings. So -far as strict sequence of subject-matter is concerned, I ought, -perhaps, at this point, to show how duplex telegraphy has -been surpassed by a recent invention, enabling three or four -or more messages to be simultaneously transmitted telegraphically. -But it will be more convenient to consider this -wonderful advance after I have described the methods by -which facsimiles of handwriting, etc., are transmitted.</p> - -<p><span class="pagenum"><a id="Page_253">253</a></span> -Hitherto we have considered the action of the electric -current in deflecting a magnetic needle to right or left, a -method of communication leaving no trace of its transmission. -We have now to consider a method at once simpler in -principle and affording means whereby a permanent record -can be left of each message transmitted.</p> - -<div class="figdummyr"> </div> -<div id="ip_253" class="figright" style="max-width: 13.125em;"> - <img src="images/i_253.jpg" width="210" height="169" class="dummy" alt="" /> - <div class="caption"><span class="smcap">Fig. 6.</span></div></div> - -<p>If the insulated wire is twisted in the form of a helix or -coil round a bar of soft iron, the -bar becomes magnetized while -the current is passing. If the -bar be bent into the horse-shoe -form, as in <a href="#ip_253">Fig. 6</a>, where <span class="smcap">A C B</span> -represents the bar, <i>a b c d e f</i> -the coil of insulated wire, the -bar acts as a magnet while the -current is passing along the coil, -but ceases to do so as soon as -the current is interrupted.<a id="FNanchor_30" href="#Footnote_30" class="fnanchor">30</a> If, -then, we have a telegraphic wire from a distant station in -electric connection with the wire <i>a b c</i>, the part <i>e f</i> descending -to an earth-plate, then, according as the operator at that -distant station transmits or stops the current, the iron <span class="smcap">A C B</span> -is magnetized or demagnetized. The part <span class="smcap smaller">C</span> is commonly -replaced by a flat piece of iron, as is supposed to be the -case with the temporary magnets shown in <a href="#ip_254">Fig. 7</a>, where this -flat piece is below the coils.</p> - -<p>So far back as 1838 this property was applied by Morse -in America in the recording instrument which bears his -name, and is now (with slight modifications) in general use -not only in America but on the Continent. The principle<span class="pagenum"><a id="Page_254">254</a></span> -of this instrument is exceedingly simple. Its essential parts -are shown in <a href="#ip_254">Fig. 7</a>; <span class="smcap smaller">H</span> is the handle, <span class="smcap smaller">H</span> <i>b</i> the lever of the -manipulator at the station <span class="smcap smaller">A</span>. The manipulator is shown in -the position for receiving a message from the station <span class="smcap smaller">B</span> along -the wire <span class="smcap smaller">W</span>. The handle <span class="smcap">H´</span> of the manipulator at the station -<span class="smcap smaller">B</span> is shown depressed, making connection at <i>a´</i> with the wire -from the battery <span class="smcap">N´ P´</span>. Thus a current passes through the -handle to <i>c´</i>, along the wire to <i>c</i> and through <i>b</i> to the coil of -the temporary magnet <span class="smcap smaller">M</span>, after circling which it passes to the -earth at <i>e</i> and so by <span class="smcap">E´</span> to the negative pole <span class="smcap">N´</span>. The passage -of this current magnetizes <span class="smcap smaller">M</span>, which draws down the armature -<i>m</i>. Thus the lever <i>l</i>, pulled down on this side, presses upwards -the pointed style <i>s</i> against a strip of paper <i>p</i> which is -steadily rolled off from the wheel <span class="smcap smaller">W</span> so long as a message is -being received. (The mechanism for this purpose is not -indicated in <a href="#ip_254">Fig. 7</a>.) Thus, so long as the operator at <span class="smcap smaller">B</span> -holds down the handle <span class="smcap">H´</span>, the style <i>s</i> marks the moving -strip of paper, the spring <i>r</i>, under the lever <i>s l</i>, drawing the -style away so soon as the current ceases to flow and the -magnet to act. If he simply depresses the handle for an -instant, a dot is marked; if longer, a dash; and by various -combinations of dots and dashes all the letters, numerals, etc., -are indicated. When the operator at <span class="smcap smaller">B</span> has completed his -message, the handle <span class="smcap">H´</span> being raised by the spring under it -(to the position in which <span class="smcap smaller">H</span> is shown), a message can be -received at <span class="smcap smaller">B</span>.</p> - -<div id="ip_254" class="figcenter" style="max-width: 36.4375em;"> - <img src="images/i_254.jpg" width="583" height="194" alt="" /> - <div class="caption"><span class="smcap">Fig. 7.</span></div></div> - -<p><span class="pagenum"><a id="Page_255">255</a></span> -I have in the figure and description assumed that the -current from either station acts directly on the magnet -which works the recording style. Usually, in long-distance -telegraphy, the current is too weak for this, and the magnet -on which it acts is used only to complete the circuit of a -local battery, the current from which does the real work of -magnetizing <span class="smcap smaller">M</span> at <span class="smcap smaller">A</span> or <span class="smcap">M´</span> at <span class="smcap smaller">B</span>, as the case may be. A local -battery thus employed is called a <em>relay</em>.</p> - -<p>The Morse instrument will serve to illustrate the <em>principle</em> -of the methods by which facsimiles are obtained. The -details of construction are altogether different from those -of the Morse instrument; they also vary greatly in different -instruments, and are too complex to be conveniently described -here. But the principle, which is the essential point, -can be readily understood.</p> - -<p>In working the Morse instrument, the operator at <span class="smcap smaller">B</span> -depresses the handle <span class="smcap">H´</span>. Suppose that this handle is kept -depressed by a spring, and that a long strip of paper passing -uniformly between the two points at <i>a</i> prevents contact. -Then no current can pass. But if there is a hole in this -paper, then when the hole reaches <i>a</i> the two metal points -at <i>a</i> meet and the current passes. We have here the -principle of the Bain telegraph. A long strip of paper is -punched with round and long holes, corresponding to the -dots and marks of a message by the Morse alphabet. As -it passes between a metal wheel and a spring, both forming -part of the circuit, it breaks the circuit until a hole allows -the spring to touch the wheel, either for a short or longer -time-interval, during which the current passes to the other -station, where it sets a relay at work. In Bain’s system -the message is received on a chemically prepared strip of -paper, moving uniformly at the receiving station, and connected -with the negative pole of the relay battery. When -contact is made, the face of the paper is touched by a -steel pointer connected with the positive pole, and the -current which passes from the end of the pointer through<span class="pagenum"><a id="Page_256">256</a></span> -the paper to the negative pole produces a blue mark on the -chemically prepared paper.<a id="FNanchor_31" href="#Footnote_31" class="fnanchor">31</a></p> - -<p>We see that by Bain’s arrangement a paper is marked -with dots and lines, corresponding to round and elongated -holes, in a ribbon of paper. It is only a step from this to -the production of facsimiles of writings or drawings.</p> - -<p>Suppose a sheet of paper so prepared as to be a conductor -of electricity, and that a message is written on the -paper with some non-conducting substance for ink. If that -sheet were passed between the knobs at <i>a</i> (the handle <span class="smcap smaller">H</span> -being pressed down by a spring), whilst simultaneously a -sheet of Bain’s chemically prepared paper were passed -athwart the steel pointer at the receiving station, there -would be traced across the last-named paper a blue line, -which would be broken at parts corresponding to those on -the other paper where the non-conducting ink interrupted -the current. Suppose the process repeated, each paper -being slightly shifted so that the line traced across either -would be parallel and very close to the former, but precisely -corresponding as respects the position of its length. Then -this line, also, on the recording paper will be broken at -parts corresponding to those in which the line across the -transmitting paper meets the writing. If line after line be -drawn in this way till the entire breadth of the transmitting -paper has been crossed by close parallel lines, the -entire breadth of the receiving paper will be covered by -closely marked blue lines except where the writing has -broken the contact. Thus a negative facsimile of the -writing will be found in the manner indicated in Figs. 8 -and 9.<a id="FNanchor_32" href="#Footnote_32" class="fnanchor">32</a> In reality, in processes of this kind, the papers -(unlike the ribbons on Bain’s telegraph) are not carried -across in the way I have imagined, but are swept by<span class="pagenum"><a id="Page_257">257</a></span> -successive strokes of a movable pointer, along which the -current flows; but the principle is the same.</p> - -<div id="ip_257" class="figcenter" style="max-width: 37.6875em;"> - <img src="images/i_257.jpg" width="603" height="263" alt="" /> - <div class="caption floatl"><span class="smcap">Fig. 8.</span></div> - <div class="caption floatr"><span class="smcap">Fig. 9.</span></div></div> - -<p>It is essential, in such a process as I have described, -first, that the recording sheet should be carried athwart the -pointer which conveys the marking current (or the pointer -carried across the recording sheet) in precise accordance -with the motion of the transmitting sheet athwart the wire -or style which conveys the current to the long wire between -the stations (or of this style across the transmitting sheet). -The recording sheet and the transmitting sheet must also -be shifted between each stroke by an equal amount. The -latter point, is easily secured; the former is secured by -causing the mechanism which gives the transmitting style -its successive strokes to make and break circuit, by which -a temporary magnet at the receiving station is magnetized -and demagnetized; by the action of this magnet the recording -pointer is caused to start on its motion athwart the -receiving sheet, and moving uniformly it completes its -thwart stroke at the same instant as the transmitting style.</p> - -<p>Caselli’s pantelegraph admirably effects the transmission -of facsimiles. The transmitting style is carried by the -motion of a heavy pendulum in an arc of constant range -over a cylindrical surface on which the paper containing the<span class="pagenum"><a id="Page_258">258</a></span> -message, writing, or picture, is spread. As the swing of the -pendulum begins, a similar pendulum at the receiving station -begins its swing; the same break of circuit which (by demagnetizing -a temporary magnet) releases one, releases the -other also. The latter swings in an arc of precisely the -same range, and carries a precisely similar style over a -similar cylindrical surface on which is placed the prepared -receiving paper. In fact, the same pendulum at either -station is used for transmitting and for receiving facsimiles. -Nay, not only so, but each pendulum, as it swings, serves in -the work both of transmitting and recording facsimiles. As -it swings one way, it travels along a line over each of two -messages or drawings, while the other pendulum in its -synchronous swing traces a corresponding line over each of -two receiving sheets; and as it swings the other way, it -traces a line on each of two receiving sheets, corresponding -to the lines along which the transmitting style of the other -is passing along two messages or drawings. Such, at least, -is the way in which the instrument works in busy times. It -can, of course, send a message, or two messages, without -receiving any.<a id="FNanchor_33" href="#Footnote_33" class="fnanchor">33</a></p> - -<p>In Caselli’s pantelegraph matters are so arranged that -instead of a negative facsimile, like <a href="#ip_257">Fig. 9</a>, a true facsimile is -obtained in all respects except that the letters and figures -are made by closely set dark lines instead of being dark -throughout as in the message. The transmitting paper is -conducting and the ink non-conducting, as in Bakewell’s -original arrangement; but instead of the conducting paper -completing the circuit for the distant station, it completes a -short home circuit (so to speak) along which the current -travels without entering on the distant circuit When the -non-conducting ink breaks the short circuit, the current<span class="pagenum"><a id="Page_259">259</a></span> -travels in the long circuit through the recording pointer at -the receiving station; and a mark is thus made corresponding -to the inked part of the transmitting sheet instead of the -blank part, as in the older plan.</p> - -<p>The following passage from Guillemin’s “Application -of the Physical Forces” indicates the effectiveness of -Caselli’s pantelegraph not only as respects the character of -the message it conveys, but as to rapidity of transmission. -(I alter the measures from the metric to our usual system of -notation.<a id="FNanchor_34" href="#Footnote_34" class="fnanchor">34</a>) “Nothing is simpler than the writing of the -pantelegraph. The message when written is placed on the -surface of the transmitting cylinder. The clerk makes the -warning signals, and then sets the pendulum going. The -transmission of the message is accomplished automatically, -without the clerk having any work to do, and consequently -without [his] being obliged to acquire any special knowledge. -Since two despatches may be sent at the same time—and -since shorthand may be used—the rapidity of transmission -may be considerable.” “The long pendulum of Caselli’s -telegraph,” says M. Quet, “generally performs about forty -oscillations a minute, and the styles trace forty broken lines, -separated from each other by less than the hundredth part -of an inch. In one minute the lines described by the style -have ranged over a breadth of more than half an inch, and -in twenty minutes of nearly 10½ inches. As we can give the -lines a length of 4¼ inches, it follows that in twenty minutes -Caselli’s apparatus furnishes the facsimile of the writing or -drawing traced on a metallized plate 4¼ inches broad by 10½ -inches long. For clearness of reproduction, the original -writing must be very legible and in large characters.” -“Since 1865 the line from Paris to Lyons and Marseilles has -been open to the public for the transmission of messages by -this truly marvellous system.”</p> - -<p><span class="pagenum"><a id="Page_260">260</a></span> -It will easily be seen that Caselli’s method is capable of -many important uses besides the transmission of facsimiles -of handwriting. For instance, by means of it a portrait of -some person who is to be identified—whether fraudulent -absconder, or escaped prisoner or lunatic, or wife who has -eloped from her husband, or husband who has deserted his -wife, or missing child, and so on—can be sent in a few -minutes to a distant city where the missing person is likely -to be. All that is necessary is that from a photograph or -other portrait an artist employed for the purpose at the -transmitting station should, in bold and heavy lines, sketch -the lineaments of the missing person on one of the prepared -sheets, as in <a href="#ip_260">Fig. 10</a>. The portrait at the receiving station -will appear as in <a href="#ip_260">Fig. 11</a>, and if necessary an artist at this -station can darken the lines or in other ways improve the -picture without altering the likeness.</p> - -<div id="ip_260" class="figcenter" style="max-width: 32.6875em;"> - <img src="images/i_260.jpg" width="523" height="422" alt="" /> - <div class="caption floatl"><span class="smcap">Fig. 10.</span></div> - <div class="caption floatr"><span class="smcap">Fig. 11.</span></div></div> - -<p><span class="pagenum"><a id="Page_261">261</a></span> -But now we must turn to the greatest marvel of all—the -transmission of tones, tunes, and words by the electric wire.</p> - -<p>The transmission of the rhythm of an air is of course a -very simple matter. I have seen the following passage from -“Lardner’s Museum of Science and Art,” 1859, quoted as -describing an anticipation of the telephone, though in reality -it only shows what every one who has heard a telegraphic -indicator at work must have noticed, that the click of the -instrument may be made to keep time with an air. “We -were in the Hanover Street Office, when there was a pause -in the business operations. Mr. M. Porter, of the office at -Boston—the writer being at New York—asked what tune -we would have? We replied, ‘Yankee Doodle,’ and to our -surprise he immediately complied with our request. The -instrument, a Morse one, commenced drumming the notes -of the tune as perfectly and distinctly as a skilful drummer -could have made them at the head of a regiment, and many -will be astonished to hear that ‘Yankee Doodle’ can travel -by lightning.... So perfectly and distinctly were the -sounds of the tunes transmitted, that good instrumental -performers could have no difficulty in keeping time with the -instruments at this end of the wires.... That a pianist -in London should execute a fantasia at Paris, Brussels, -Berlin, and Vienna, at the same moment, and with the same -spirit, expression, and precision as if the instruments at these -distant places were under his fingers, is not only within the -limits of practicability, but really presents no other difficulty -than may arise from the expense of the performances. From -what has just been stated, it is clear that the time of music -has been already transmitted, and the production of the -sounds does not offer any more difficulty than the printing -of the letters of a despatch.” Unfortunately, Lardner -omitted to describe how this easy task was to be achieved.</p> - -<p>Reuss first in 1861 showed how a sound can be transmitted. -At the sending station, according to his method, -there is a box, into which, through a pipe in the side, the -note to be transmitted is sounded. The box is open at the<span class="pagenum"><a id="Page_262">262</a></span> -top, and across it, near the top, is stretched a membrane -which vibrates synchronously with the aerial vibrations corresponding -to the note. At the middle of the membrane, -on its upper surface, is a small disc of metal, connected by -a thin strip of copper with the positive pole of the battery at -the transmitting station. The disc also, when the machine -is about to be put in use, lightly touches a point on a metallic -arm, along which (while this contact continues) the electric -current passes to the wire communicating with the distant -station. At that station the wire is carried in a coil round -a straight rod of soft iron suspended horizontally in such a -way as to be free to vibrate between two sounding-boards. -After forming this coil, the wire which conveys the current -passes to the earth-plate and so home. As already explained, -while the current passes, the rod of iron is magnetized, but -the rod loses its magnetization when the current ceases.</p> - -<p>Now, when a note is sounded in the box at the transmitting -station, the membrane vibrates, and at each vibration -the metal disc is separated from the point which it lightly -touches when at rest. Thus contact is broken at regular -intervals, corresponding to the rate of vibration due to the -note. Suppose, for instance, the note <i>C</i> is sounded; then -there are 256 complete vibrations in a second, the electric -current is therefore interrupted and renewed, and the bar of -soft iron magnetized and demagnetized, 256 times in a second. -Now, it had been discovered by Page and Henry that when -a bar of iron is rapidly magnetized and demagnetized, it is -put into vibrations synchronizing with the interruptions of -the current, and therefore emits a note of the same tone as -that which has been sounded into the transmitting box.</p> - -<p>Professor Heisler, in his “Lehrbuch der technischen -Physik,” 1866, wrote of Reuss’s telephone: “The instrument -is still in its infancy; however, by the use of batteries of proper -strength, it already transmits not only single musical tones, -but even the most intricate melodies, sung at one end of the -line, to the other, situated at a great distance, and makes -them perceptible there with all desirable distinctness.” Dr.<span class="pagenum"><a id="Page_263">263</a></span> -Van der Weyde, of New York, states that, after reading an -account of Reuss’s telephone, he had two such instruments -constructed, and exhibited them at the meeting of the Polytechnic -Club of the American Institute. “The original -sounds were produced at the furthest extremity of the large -building (the Cooper Institute), totally out of hearing of the -Association; and the receiving instrument, standing on the -table in the lecture-room, produced, with a peculiar and -rather nasal twang, the different tunes sung into the box at -the other end of the line; not powerfully, it is true, but very -distinctly and correctly. In the succeeding summer I -improved the form of the box, so as to produce a more -powerful vibration of the membrane. I also improved the -receiving instrument by introducing several iron wires into -the coil, so as to produce a stronger vibration. I submitted -these, with some other improvements, to the meeting of the -American Association for the Advancement of Science, and -on that occasion (now seven years ago) expressed the opinion -that the instrument contained the germ of a new method of -working the electric telegraph, and would undoubtedly lead -to further improvements in this branch of science.”</p> - -<p>The telephonic successes recently achieved by Mr. Gray -were in part anticipated by La Cour, of Copenhagen, whose -method may be thus described: At the transmitting station -a tuning-fork is set in vibration. At each vibration one of -the prongs touches a fine strip of metal completing a circuit. -At the receiving station the wire conveying the electric current -is coiled round the prongs of another tuning-fork of the -same tone, but without touching them. The intermittent -current, corresponding as it does with the rate of vibration -proper to the receiving fork, sets this fork in vibration; and -in La Cour’s instrument the vibrations of the receiving fork -were used to complete the circuit of a local battery. His -object was not so much the production of tones as the use -of the vibrations corresponding to different tones, to act on -different receiving instruments. For only a fork corresponding -to the sending fork could be set in vibration by the<span class="pagenum"><a id="Page_264">264</a></span> -intermittent current resulting from the latter’s vibrations. -So that, if there were several transmitting forks, each could -send its own message at the same time, each receiving fork -responding only to the vibrations of the corresponding transmitting -fork. La Cour proposed, in fact, that his instrument -should be used in combination with other methods of telegraphic -communication. Thus, since the transmitting fork, -whenever put in vibration, sets the local battery of the -receiving station at work, it can be used to work a Morse -instrument, or it could work an ordinary Wheatstone and -Cook instrument, or it could be used for a pantelegraph. -The same wire, when different forks are used, could work -simultaneously several instruments at the receiving station. -One special use indicated by La Cour was the adaptation of -his system to the Caselli pantelegraph, whereby, instead of -one style, a comb of styles might be carried over the transmitting -and recording plates. It would be necessary, in all -such applications of his method (though, strangely enough, -La Cour’s description makes no mention of the point), that -the vibrations of the transmitting fork should admit of being -instantly stopped or “damped.”</p> - -<p>Mr. Gray’s system is more directly telephonic, as aiming -rather at the development of sound itself than at the transmission -of messages by the vibrations corresponding to -sound. A series of tuning-forks are used, which are set in -separate vibration by fingering the notes of a key-board. -The vibrations are transmitted to a receiving instrument -consisting of a series of reeds, corresponding in note to the -series of transmitting forks, each reed being enclosed in a -sounding-box. These boxes vary in length from two feet to -six inches, and are connected by two wooden bars, one of -which carries an electro-magnet, round the coils of which -pass the currents from the transmitting instrument. When -a tuning-fork is set in vibration by the performer at the -transmitting key-board, the electro-magnet is magnetized -and demagnetized synchronously with the vibrations of the -fork. Not only are vibrations thus imparted to the reed of<span class="pagenum"><a id="Page_265">265</a></span> -corresponding note, but these are synchronously strengthened -by thuds resulting from the lengthening of the iron when -magnetized.</p> - -<p>So far as its musical capabilities are concerned, Gray’s -telephone can hardly be regarded as fulfilling all the hopes -that have been expressed concerning telephonic music. -“Dreaming enthusiasts of a prophetic turn of mind foretold,” -we learn, “that a time would come when future Pattis -would sing on a London stage to audiences in New York, -Berlin, St. Petersburg, Shanghai, San Francisco, and Constantinople -all at once.” But the account of the first concert -given at a distance scarcely realizes these fond expectations. -When “Home, Sweet Home,” played at Philadelphia, came -floating through the air at the Steinway Hall, New York, -“the sound was like that of a distant organ, rather faint, for -a hard storm was in progress, and there was consequently a -great leakage of the electric current, but quite clear and -musical. The lower notes were the best, the higher being -sometimes almost inaudible. ‘The Last Rose of Summer,’ -‘Com’ è gentil,’ and other melodies, followed, with more or -less success. There was no attempt to play chords,” though -three or four notes can be sounded together. It must be -confessed that the rosy predictions of M. Strakosch (the -<i xml:lang="it" lang="it">impresario</i>) “as to the future of this instrument seem rather -exalted, and we are not likely as yet to lay on our music -from a central reservoir as we lay on gas and water, though -the experiment was certainly a very curious one.”</p> - -<p>The importance of Mr. Gray’s, as of La Cour’s inventions, -depends, however, far more on the way in which they -increase the message-bearing capacity of telegraphy than on -their power of conveying airs to a distance. At the Philadelphia -Exhibition, Sir W. Thomson heard four messages -sounded simultaneously by the Gray telephone. The Morse -alphabet was used. I have mentioned that in that alphabet -various combinations of dots and dashes are used to represent -different letters; it is only necessary to substitute the -short and long duration of a note for dots and dashes to have a<span class="pagenum"><a id="Page_266">266</a></span> -similar sound alphabet. Suppose, now, four tuning-forks at -the transmitting station, whose notes are <i>Do</i> <img class="inline" src="images/i_266.jpg" width="60" height="34" alt="Do" />, <i>Mi</i>, -<i>Sol</i>, and <i>Do</i> <img class="inline" src="images/i_266a.jpg" width="60" height="33" alt="Do" />, or say <i>C</i>, <i>E</i>, <i>G</i>, and <i>C</i>´, then by each -of these forks a separate message may be transmitted, all the -messages being carried simultaneously by the same line to -separate sounding reeds (or forks, if preferred), and received -by different clerks. With a suitable key-board, a single -clerk could send the four messages simultaneously, striking -chords instead of single notes, though considerable practice -would be necessary to transform four verbal messages at -once into the proper telephonic music, and some skill in -fingering to give the proper duration to each note.</p> - -<p>Lastly, we come to the greatest achievement of all, Professor -Graham Bell’s vocal telephone. In the autumn of -1875 I had the pleasure of hearing from Professor Bell in the -course of a ride—all too short—from Boston to Salem, Mass., -an account of his instrument as then devised, and of his -hopes as to future developments. These hopes have since -been in great part fulfilled, but I venture to predict that we -do not yet know all, or nearly all, that the vocal telephone, -in Bell’s hands, is to achieve.</p> - -<p>It ought to be mentioned at the outset that Bell claims -to have demonstrated in 1873 (a year before La Cour) the -possibility of transmitting several messages simultaneously -by means of the Morse alphabet.</p> - -<p>Bell’s original arrangement for vocal telephony was as -follows:—At one station a drumhead of goldbeaters’ skin, -about 2¾ inches in diameter, was placed in front of an -electro-magnet. To the middle of the drumhead, on the -side towards the magnet, was glued a circular piece of clockspring. -A similar electro-magnet, drumhead, etc., were -placed at the other station. When notes were sung or -words spoken before one drumhead, the vibrations of the -goldbeaters’ skin carried the small piece of clockspring<span class="pagenum"><a id="Page_267">267</a></span> -vibratingly towards and from the electro-magnet, without -producing actual contact. Now, the current which was -passing along the coil round the electro-magnet changed in -strength with each change of position of this small piece of -metal. The more rapid the vibrations, and the greater -their amplitude, the more rapid and the more intense were -the changes in the power of the electric current. Thus, the -electro-magnet at the other station underwent changes of -power which were synchronous with, and proportionate to, -those changes of power in the current which were produced -by the changes of position of the vibrating piece of clockspring. -Accordingly, the piece of clockspring at the receiving -station, and with it the drumhead there, was caused by -the electro-magnet to vibrate with the same rapidity and -energy as the piece at the transmitting station. Therefore, -as the drumhead at one station varied its vibrations in response -to the sounds uttered in its neighbourhood, so the -drumhead at the other station, varying its vibrations, emitted -similar sounds. Later, the receiving drumhead was made -unlike the transmitting one. Instead of a membrane carrying -a small piece of metal, a thin and very flexible disc of -sheet-iron, held in position by a screw, was used. This disc, -set in vibration by the varying action of an electro-magnet, -as in the older arrangement, uttered articulate sounds corresponding -to those which, setting in motion the membrane -at the transmitting station, caused the changes in the power -of the electric current and in the action of the electro-magnet.</p> - -<p>At the meeting of the British Association in 1876 -Sir W. Thomson gave the following account of the performance -of this instrument at the Philadelphia Exhibition:—“In -the Canadian department” (for Professor Bell was not at -the time an American citizen) “I heard ‘To be or not to be—there’s -the rub,’ through the electric wire; but, scorning -monosyllables, the electric articulation rose to higher flights, -and gave me passages taken at random from the New York -newspapers:—‘S. S. Cox has arrived’ (I failed to make out<span class="pagenum"><a id="Page_268">268</a></span> -the ‘S. S. Cox’), ‘the City of New York,’ ‘Senator Morton,’ -‘the Senate has resolved to print a thousand extra copies,’ -‘the Americans in London have resolved to celebrate the -coming Fourth of July.’ All this my own ears heard spoken -to me with unmistakable distinctness by the thin circular -disc armature of just such another little electro-magnet as -this which I hold in my hand. The words were shouted -with a clear and loud voice by my colleague judge, Professor -Watson, at the far end of the line, holding his mouth close -to a stretched membrane, carrying a piece of soft iron, which -was thus made to perform in the neighbourhood of an -electro-magnet, in circuit with the line, motions proportional -to the sonorific motions of the air. This, the greatest by -far of all the marvels of the electric telegraph, is due to a -young countryman of our own, Mr. Graham Bell, of Edinburgh, -and Montreal, and Boston, now about to become a -naturalized citizen of the United States. Who can but -admire the hardihood of invention which devised such very -slight means to realize the mathematical conception that, if -electricity is to convey all the delicacies of quality which -distinguish articulate speech, the strength of its current must -vary continuously, and as nearly as may be in simple proportion -to the velocity of a particle of air engaged in constituting -the sound?”</p> - -<p>Since these words were spoken by one of the highest -authorities in matters telegraphic, Professor Bell has introduced -some important modifications in his apparatus. He -now employs, not an electro-magnet, but a permanent -magnet. That is to say, instead of using at each station -such a bar of soft iron as is shown in <a href="#ip_253">Fig. 6</a>, which becomes -a magnet while the electric current is passing through the -coil surrounding it, he uses at each station a bar of iron -permanently magnetized (or preferably a powerful magnet -made of several horse-shoe bars—that is, a compound -magnet), surrounded similarly by coils of wire. No battery -is needed. Instead of a current through the coils magnetizing -the iron, the iron already magnetized causes a current<span class="pagenum"><a id="Page_269">269</a></span> -to traverse the coils whenever it acts, or rather whenever its -action changes. If an armature were placed across its ends -or poles, at the moment when it drew that armature to the -poles by virtue of its magnetic power, a current would -traverse the coils; but afterwards, so long as the armature -remained there, there would be no current. If an armature -placed near the poles were shifted rapidly in front of the -poles, currents would traverse the coils, or be induced, their -intensity depending on the strength of the magnet, the length -of the coil, and the rapidity and range of the motions. In -front of the poles of the magnet is a diaphragm of very -flexible iron (or else some other flexible material bearing a -small piece of iron on the surface nearest the poles). A -mouthpiece to converge the sound upon this diaphragm -substantially completes the apparatus at each station. Professor -Bell thus describes the operation of the instrument:—“The -motion of steel or iron in front of the poles of a -magnet creates a current of electricity in coils surrounding -the poles of the magnet, and the duration of this current of -electricity coincides with the duration of the motion of the -steel or iron moved or vibrated in the proximity of the -magnet. When the human voice causes the diaphragm to -vibrate, electrical undulations are induced in the coils around -the magnets precisely similar to the undulations of the air -produced by the voice. The coils are connected with the -line wire, and the undulations induced in them travel through -the wire, and, passing through the coils of another instrument -of similar construction at the other end of the line, are -again resolved into air undulations by the diaphragm of this -(other) instrument.”</p> - -<p>So perfectly are the sound undulations repeated—though -the instrument has not yet assumed its final form—that not -only has the lightest whisper uttered at one end of a line of -140 miles been distinctly heard at the other, but the speaker -can be distinguished by his voice when he is known to the -listener. So far as can be seen, there is every room to -believe that before long Professor Bell’s grand invention will<span class="pagenum"><a id="Page_270">270</a></span> -be perfected to such a degree that words uttered on the -American side of the Atlantic will be heard distinctly after -traversing 2000 miles under the Atlantic, at the European -end of the submarine cable—so that Sir W. Thomson -at Valentia could tell by the voice whether Graham Bell, -or Cyrus Field, or his late colleague Professor Watson, -were speaking to him from Newfoundland. Yet a single -wave of those which toss in millions on the Atlantic, rolling -in on the Irish strand, would utterly drown the voices -thus made audible after passing beneath two thousand -miles of ocean.</p> - -<p>Here surely is the greatest of telegraphic achievements. -Of all the marvels of telegraphy—and they are many—none -are equal to, none seem even comparable with, this one. -Strange truly is the history of the progress of research -which has culminated in this noble triumph, wonderful the -thought that from the study of the convulsive twitchings of -a dead frog by Galvani, and of the quivering of delicately -poised magnetic needles by Ampère, should gradually have -arisen through successive developments a system of communication -so perfect and so wonderful as telegraphy has -already become, and promising yet greater marvels in the -future.</p> - -<p>The last paragraph had barely been written when news -arrived of another form of telephone, surpassing Gray’s and -La Cour’s in some respects as a conveyor of musical tones, -but as yet unable to speak like Bell’s. It is the invention -of Mr. Edison, an American electrician. He calls it the -motograph. He discovered about six years ago the curious -property on which the construction of the instrument -depends. If a piece of paper moistened with certain -chemical solutions is laid upon a metallic plate connected -with the positive pole of a galvanic battery, and a platinum -wire connected with the negative pole is dragged over the -moistened paper, the wire slides over the paper like smooth -iron over ice—the usual friction disappearing so long as -the current is passing from the wire to the plate through<span class="pagenum"><a id="Page_271">271</a></span> -the paper. At the receiving station of Mr. Edison’s motograph -there is a resonating box, from one face of which -extends a spring bearing a platinum point, which is pressed -by the spring upon a tape of chemically prepared paper. -This tape is steadily unwound, drawing by its friction the -platinum point, and with it the face of the resonator, outwards. -This slight strain on the face of the resonator -continues so long as no current passes from the platinum -point to the metallic drum over which the moistened tape -is rolling. But so soon as a current passes, the friction -immediately ceases, and the face of the resonator resumes -its normal position. If then at the transmitting station -there is a membrane or a very fine diaphragm (as in -Reuss’s or Bell’s arrangement) which is set vibrating by -a note of any given tone, the current, as in those arrangements, -is transmitted and stopped at intervals corresponding -to the tone, and the face of the resonating box is freed -and pulled at the same intervals. Hence, it speaks the -corresponding tone. The instrument appears to have the -advantage over Gray’s in range. In telegraphic communication -Gray’s telephone is limited to about one octave. -Edison’s extends from the deepest bass notes to the highest -notes of the human voice, which, when magnets are employed, -are almost inaudible. But Edison’s motograph has -yet to learn to speak.</p> - -<p>Other telegraphic marvels might well find a place here. -I might speak of the wonders of submarine telegraphy, -and of the marvellous delicacy of the arrangements by -which messages by the Atlantic Cable are read, and not -only read, but made to record themselves. I might dwell, -again, on the ingenious printing telegraph of Mr. Hughes, -which sets up its own types, inks them, and prints them, or -on the still more elaborate plan of the Chevalier Bonelli -“for converting the telegraph stations into so many type-setting -workshops.” But space would altogether fail me -to deal properly with these and kindred marvels. There -is, however, one application of telegraphy, especially interesting<span class="pagenum"><a id="Page_272">272</a></span> -to the astronomer, about which I must say a few words: -I mean, the employment of electricity as a regulator of time. -Here again it is the principle of the system, rather than -details of construction, which I propose to describe. Suppose -we have a clock not only of excellent construction, -but under astronomical surveillance, so that when it is a -second or so in error it is set right again by the stars. Let -the pendulum of this clock beat seconds; and at each beat -let a galvanic current be made and broken. This may be -done in many ways—thus the pendulum may at each swing -tilt up a very light metallic hammer, which forms part of -the circuit when down; or the end of the pendulum may -be covered with some non-conducting substance which -comes at each swing between two metallic springs in very -light contact, separating them and so breaking circuit; or -in many other ways the circuit may be broken. When the -circuit is made, let the current travel along a wire which -passes through a number of stations near or remote, traversing -at each the coils of a temporary magnet. Then, at -each swing of the pendulum of the regulating clock, each -magnet is magnetized and demagnetized. Thus each, once -in a second, draws to itself, and then releases its armature, -which is thereupon pulled back by a spring. Let the armature, -when drawn to the magnet, move a lever by which -one tooth of a wheel is carried forward. Then the wheel -is turned at the rate of one tooth per second. This wheel -communicates motion to others in the usual way. In fact, -we have at each station a clock driven, <em>not</em> by a weight -or spring and with a pendulum which allows one tooth of -an escapement wheel to pass at each swing, but by the -distant regulating clock which turns a driving wheel at the -rate of one tooth per second, that is, one tooth for each -swing of the regulating clock’s pendulum. Each clock, -then, keeps perfect time with the regulating clock. In -astronomy, where it is often of the utmost importance to -secure perfect synchronism of observation, or the power of -noting the exact difference of time between observations<span class="pagenum"><a id="Page_273">273</a></span> -made at distant stations, not only can the same clock thus -keep time for two observers hundreds of miles apart, but -each observer can record by the same arrangement the -moment of the occurrence of some phenomenon. For if -a tape be unwound automatically, as in the Morse instrument, -it is easy so to arrange matters that every second’s -beat of the pendulum records itself by a dot or short line -on the tape, and that the observer can with a touch make -(or break) contact at the instant of observation, and so a -mark be made properly placed between two seconds’ marks—thus -giving the precise time when the observation was -made. Such applications, however, though exceedingly -interesting to astronomers, are not among those in which -the general public take chief interest. There was one -occasion, however, when astronomical time-relations were -connected in the most interesting manner with one of the -greatest of all the marvels of telegraphy: I mean, when -the <i>Great Eastern</i> in mid-ocean was supplied regularly -with Greenwich time, and this so perfectly (and therefore -with such perfect indication of her place in the Atlantic), -that when it was calculated from the time-signals that the -buoy left in open ocean to mark the place of the cut cable -had been reached, and the captain was coming on deck -with several officers to look for it, the buoy announced its -presence by thumping the side of the great ship.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_274">274</a></span></p> - -<div class="chapter"> -<h2><a id="THE_PHONOGRAPH_OR_VOICE-RECORDER"></a><i>THE PHONOGRAPH, OR VOICE-RECORDER.</i></h2> -</div> - -<p class="in0">In the preceding essay I have described the wonderful instrument -called the telephone, which has recently become -as widely known in this country as in America, the country -of its first development. I propose now briefly to describe -another instrument—the phonograph—which, though not a -telegraphic instrument, is related in some degree to the -telephone. In passing, I may remark that some, who as -telegraphic specialists might be expected to know better, -have described the phonograph as a telegraphic invention. -A writer in the <cite>Telegraphic Journal</cite>, for instance, who had -mistaken for mine a paper on the phonograph in one of -our daily newspapers, denounced me (as the supposed -author of that paper) for speaking of the possibility of -crystallizing sound by means of this instrument; and then -went on to speak of the mistake I (that is, said author) had -made in leaving my own proper subject of study to speak of -telegraphic instruments and to expatiate on the powers of -electricity. In reality the phonograph has no relation to -telegraphy whatever, and its powers do not in the slightest -degree depend on electricity. If the case had been otherwise, -it may be questioned whether the student of astronomy, -or of any other department of science, should be considered -incompetent of necessity to describe a telegraphic instrument, -or to discuss the principles of telegraphic or electrical science. -What should unquestionably be left to the specialist, is the<span class="pagenum"><a id="Page_275">275</a></span> -description of the practical effect of details of instrumental -construction, and the like—for only he who is in the habit -of using special instruments or classes of instrument can be -expected to be competent adequately to discuss such matters.</p> - -<p>Although, however, the phonograph is not an instrument -depending, like the telephone, on the action of electricity -(in some form or other), yet it is related closely enough to -the telephone to make the mistake of the <cite>Telegraphic</cite> -journalist a natural one. At least, the mistake would be -natural enough for any one but a telegraphic specialist; the -more so that Mr. Edison is a telegraphist, and that he has -effected several important and interesting inventions in telegraphic -and electrical science. For instance, in the previous -article, pp. 270, 271, I had occasion to describe at -some length the principles of his “Motograph.” I spoke -of it as “another form of telephone, surpassing Gray’s -and La Cour’s in some respects as a conveyer of musical -tones, but as yet unable to speak like Bell’s ... in -telegraphic communication.” I proceeded: “Gray’s telephone -is limited to about one octave. Edison’s extends -from the deepest bass notes to the highest notes of the -human voice, which, when magnets are employed, are almost -inaudible; but it has yet to learn to speak.”</p> - -<p>The phonograph is an instrument which <em>has</em> learned to -speak, though it does not speak at a distance like the telephone -or the motograph. Yet there seems no special reason -why it should not combine both qualities—the power of -repeating messages at considerable intervals of time after -they were originally spoken, and the power of transmitting -them to great distances.</p> - -<p>I have said that the phonograph is an instrument closely -related to the telephone. If we consider this feature of the -instrument attentively, we shall be led to the clearer recognition -of the acoustical principles on which its properties -depend, and also of the nature of some of the interesting -acoustical problems on which light seems likely to be thrown -by means of experiments with this instrument.</p> - -<p><span class="pagenum"><a id="Page_276">276</a></span> -In the telephone a stretched membrane, or a diaphragm -of very flexible iron, vibrates when words are uttered in its -neighbourhood. When a stretched membrane is used, with -a small piece of iron at the centre, this small piece of iron, -as swayed by the vibrations of the membrane, causes electrical -undulations to be induced in the coils round the poles -of a magnet placed in front of the membrane. These undulations -travel along the wire and pass through the coils of -another instrument of similar construction at the other end -of the wire, where, accordingly, a stretched membrane -vibrates precisely as the first had done. The vibrations of -this membrane excite atmospheric vibrations identical in -character with those which fell upon the first membrane -when the words were uttered in its neighbourhood; and -therefore the same words appear to be uttered in the neighbourhood -of the second membrane, however far it may be -from the transmitting membrane, so only that the electrical -undulations are effectually transmitted from the sending to -the receiving instrument.</p> - -<p>I have here described what happened in the case of that -earlier form of the telephone in which a stretched membrane -of some such substance as goldbeater’s skin was employed, -at the centre of which only was placed a small piece of iron. -For in its bearing on the subject of the phonograph, this -particular form of telephonic diaphragm is more suggestive -than the later form in which very flexible iron was employed. -We see that the vibrations of a small piece of iron at the -centre of a membrane are competent to reproduce all the -peculiarities of the atmospheric waves which fall upon the -membrane when words are uttered in its neighbourhood. -This must be regarded, I conceive, as a remarkable acoustical -discovery. Most students of acoustics would have -surmised that to reproduce the motions merely of the central -parts of a stretched diaphragm would be altogether insufficient -for the reproduction of the complicated series of -sound-waves corresponding to the utterance of words. I -apprehend that if the problem had originally been suggested<span class="pagenum"><a id="Page_277">277</a></span> -simply as an acoustical one, the idea entertained would have -been this—that though the motions of a diaphragm receiving -vocal sound-waves <em>might</em> be generated artificially in such -sort as to produce the same vocal sounds, yet this could only -be done by first determining what particular points of the -diaphragm were centres of motion, so to speak, and then -adopting some mechanical arrangements for giving to small -portions of the membrane at these points the necessary -oscillating motions. It would not, I think, have been -supposed that motions communicated to the centre of the -diaphragm would suffice to make the whole diaphragm -vibrate properly in all its different parts.</p> - -<p>Let us briefly consider what was before known about the -vibrations of plates, discs, and diaphragms, when particular -tones were sounded in their neighbourhood; and also what -was known respecting the requirements for vocal sounds -and speech as distinguished from simple tones. I need -hardly say that I propose only to consider these points in a -general, not in a special, manner.</p> - -<p>We must first carefully draw a distinction between the -vibrations of a plate or disc which is itself the source of -sound, and those vibrations which are excited in a plate or -disc by sound-waves otherwise originated. If a disc or -plate of given size be set in vibration by a blow or other -impulse it will give forth a special sound, according to the -place where it is struck, or it will give forth combinations of -the several tones which it is capable of emitting. On the -other hand, experiment shows that a diaphragm like that -used in the telephone—not only the electric telephone, but -such common telephones as have been sold of late in large -quantities in toy shops, etc.—will respond to any sounds -which are properly directed towards it, not merely reproducing -sounds of different tones, but all the peculiarities -which characterize vocal sounds. In the former case, the -size of a disc and the conditions under which it is struck -determine the nature of its vibrations, and the air responds -to the vibrations thus excited; in the latter, the air is set<span class="pagenum"><a id="Page_278">278</a></span> -moving in vibrations of a special kind by the sounds or -words uttered, and the disc or diaphragm responds to these -vibrations. Nevertheless, though it is important that this distinction -be recognized, we can still learn, from the behaviour -of discs and plates set in vibration by a blow or other impulse, -the laws according to which the actual motions of the -various parts of a vibrating disc or plate take place. We -owe to Chladni the invention of a method for rendering -visible the nature of such motions.</p> - -<p>Certain electrical experiments of Lichtenberg suggested -to Chladni the idea of scattering fine sand over the plate or -disc whose motions he wished to examine. If a horizontal -plate covered with fine sand is set in vibration, those parts -which move upwards and downwards scatter the sand from -their neighbourhood, while on those points which undergo -no change of position the sand will remain. Such points are -called <em>nodes</em>; and rows of such points are called <em>nodal lines</em>, -which may be either straight or curved, according to circumstances.</p> - -<p>If a square plate of glass is held by a suitable clamp at -its centre, and the middle point of a side is touched while -a bow is drawn across the edge near a corner, the sand is -seen to gather in the form of a cross dividing the square into -four equal squares—like a cross of St George. If the -finger touches a corner, and the bow is drawn across the -middle of a side, the sand forms a cross dividing the square -along its diagonals—like a cross of St Andrew. Touching -two points equidistant from two corners, and drawing the -bow along the middle of the opposite edge, we get the -diagonal cross and also certain curved lines of sand -systematically placed in each of the four quarters into which -the diagonals divide the square. We also have, in this case, -a far shriller note from the vibrating plate. And so, by -various changes in the position of the points clamped by the -finger and of the part of the edge along which the bow is -drawn, we can obtain innumerable varieties of nodal lines -and curves along which the sand gathers upon the surface of -the vibrating plate.</p> - -<p><span class="pagenum"><a id="Page_279">279</a></span> -When we take a circular plate of glass, clamped at the -middle, and touching one part of its edge with the finger, -draw the bow across a point of the edge half a quadrant from -the finger, we see the sand arrange itself along two diameters -intersecting at right angles. If the bow is drawn at a point -one-third a quadrant from the finger-clamped point, we get -a six-pointed star. If the bow is drawn at a point a fourth -of a quadrant from the finger-clamped point, we get an eight-pointed -star. And so we can get the sand to arrange itself -into a star of any even number of points; that is, we can get -a star of four, six, eight, ten, twelve, etc., points, but not of -three, five, seven, etc.</p> - -<p>In these cases the centre of the plate or disc has been -fixed. If, instead, the plate or disc be fixed by a clip at the -edge, or clamped elsewhere than at the centre, we find the -sand arranging itself into other forms, in which the centre -may or may not appear; that is, the centre may or may not -be nodal, according to circumstances.</p> - -<p>A curious effect is produced if very fine powder be strewn -along with the sand over the plate. For it is found that the -dust gathers, not where the nodes or places of no vibration -lie, but where the motion is greatest. Faraday assigns as the -cause of this peculiarity the circumstance that “the light -powder is entangled by the little whirlwinds of air produced -by the vibrations of the plate; it cannot escape from the -little cyclones, though the heavier sand particles are readily -driven through them; when, therefore, the motion ceases, -the light powder settles down in heaps at the places where -the vibration was a maximum.” In proof of this theory we -have the fact that “in vacuo no such effect is produced; all -powders light and heavy move to the nodal lines.” (Tyndall -on “Sound.”)</p> - -<p>Now if we consider the meaning of such results as these, -we shall begin to recognize the perplexing but also instructive -character of the evidence derived from the telephone, and -applied to the construction of the phonograph. It appears -that when a disc is vibrating under such special conditions<span class="pagenum"><a id="Page_280">280</a></span> -as to give forth a particular series of tones (the so-called -fundamental tone of the disc and other tones combined -with it which belong to its series of overtones), the various -parts of the disc are vibrating to and fro in a direction square -to the face of the disc, except certain points at which there -is no vibration, these points together forming curves of -special forms along the substance of the disc.</p> - -<p>When, on the other hand, tones of various kinds are -sounded in the neighbourhood of a disc or of a stretched -circular membrane, we may assume that the different parts of -the disc are set in vibration after a manner at least equally -complicated. If the tones belong to the series which could -be emitted by the diaphragm when struck, we can understand -that the vibrations of the diaphragm would resemble those -which would result from a blow struck under special conditions. -When other tones are sounded, it may be assumed -that the sound-waves which reach the diaphragm cause it to -vibrate as though not the circumference (only) but a circle -in the substance of the diaphragm—concentric, of course, -with the circumference, and corresponding in dimensions -with the tone of the sounds—were fixed. If a drum of given -size is struck, we hear a note of particular tone. If we heard, -as the result of a blow on the same drum, a much higher -tone, we should know that in some way or other the effective -dimensions of the drum-skin had been reduced—as for -instance, by a ring firmly pressed against the inside of the -skin. So when a diaphragm is responding to tones other -than those corresponding to its size, tension, etc., we infer -that the sound-waves reaching it cause it to behave, so far as -its effective vibrating portion is concerned, as though its -conformation had altered. When several tones are responded -to by such a diaphragm, we may infer that the vibrations of -the diaphragm are remarkably complicated.</p> - -<p>Now the varieties of vibratory motion to which the -diaphragm of the telephone has been made to respond have -been multitudinous. Not only have all orders of sound singly -and together been responded to, but vocal sounds which in<span class="pagenum"><a id="Page_281">281</a></span> -many respects differ widely from ordinary tones are repeated, -and the peculiarities of intonation which distinguish one -voice from another have been faithfully reproduced.</p> - -<p>Let us consider in what respects vocal sounds, and -especially the sounds employed in speech, differ from mere -combinations of ordinary tones.</p> - -<p>It has been said, and with some justice, that the organ -of voice is of the nature of a reed instrument. A reed -instrument, as most persons know, is one in which musical -sounds are produced by the action of a vibrating reed in -breaking up a current of air into a series of short puffs. -The harmonium, accordion, concertina, etc., are reed instruments, -the reed for each note being a fine strip of metal -vibrating in a slit. The vocal organ of man is at the top of -the windpipe, along which a continuous current of air can be -forced by the lungs. Certain elastic bands are attached to the -head of the windpipe, almost closing the aperture. These vocal -chords are thrown into vibration by the current of air from -the lungs; and as the rate of their vibration is made to vary -by varying their tension, the sound changes in tone. So far, -we have what corresponds to a reed instrument admitting of -being altered in pitch so as to emit different notes. The -mouth, however, affects the character of the sound uttered -from the throat. The character of a <em>tone</em> emitted by the -throat cannot be altered by any change in the configuration -of the mouth; so that if a single tone were in reality produced -by the vocal chords, the resonance of the mouth -would only strengthen that tone more or less according to -the figure given to the cavity of the mouth at the will of the -singer or speaker. But in reality, besides the fundamental -tone uttered by the vocal chords, a series of overtones are -produced. Overtones are tones corresponding to vibration -at twice, three times, four times, etc., the rate of the vibration -producing the fundamental tone. Now the cavity of the -mouth can be so modified in shape as to strengthen either -the fundamental tone or any one of these overtones. And -according as special tones are strengthened in this way<span class="pagenum"><a id="Page_282">282</a></span> -various vocal sounds are produced, without changing the -pitch or intensity of the sound actually uttered. Calling the -fundamental tone the first tone, the overtones just mentioned -the second, third, fourth, etc., tones respectively (after Tyndall), -we find that the following relations exist between the -combinations of these tones and the various vowel sounds:—</p> - -<p>If the lips are pushed forward so as to make the cavity -of the mouth deep and the orifice of the mouth small, we -get the deepest resonance of which the mouth is capable, -the fundamental tone is reinforced, while the higher tones -are as far as possible thrown into the shade. The resulting -vowel sound is that of deep U (“oo” in “hoop”).</p> - -<p>If the mouth is so far opened that the fundamental tone -is accompanied by a strong second tone (the next higher -octave to the fundamental tone), we get the vowel sound O -(as in “hole”). The third and fourth tones feebly accompanying -the first and second make the sound more perfect, -but are not necessary.</p> - -<p>If the orifice of the mouth is so widened, and the volume -of the cavity so reduced, that the fundamental tone is lost, -the second somewhat weakened, and the third given as the -chief tone, with very weak fourth and fifth tones, we have -the vowel sound A.</p> - -<p>To produce the vowel sound E, the resonant cavity of -the mouth must be considerably reduced. The fourth tone -is the characteristic of this vowel. Yet the second tone also -must be given with moderate strength. The first and third -tones must be weak, and the fifth tone should be added with -moderate strength.</p> - -<p>To produce the vowel sound A, as in “far,” the higher -overtones are chiefly used, the second is wanting altogether, -the third feeble, the higher tones—especially the fifth and -seventh—strong.</p> - -<p>The vowel sound I, as in “fine,” it should be added, is -not a simple sound, but diphthongal. The two sounds whose -succession gives the sound we represent (erroneously) by a -single letter I (long), are not very different from “a” as in<span class="pagenum"><a id="Page_283">283</a></span> -“far,” and “ee” (or “i” as in “ravine”); they, lie, however, -in reality, respectively between “a” in “far” and -“fat,” and “i” in “ravine” and “pin.” Thus the tones and -overtones necessary for sounding “I” long, do not require -a separate description, any more than those necessary for -sounding other diphthongs, as “oi,” “oe,” and so forth.</p> - -<p>We see, then, that the sound-waves necessary to reproduce -accurately the various vowel sounds, are more -complicated than those which would correspond to the -fundamental tones simply in which any sound may be uttered. -There must not only be in each case certain overtones, but -each overtone must be sounded with its due degree of -strength.</p> - -<p>But this is not all, even as regards the vowel sounds, the -most readily reproducible peculiarities of ordinary speech. -Spoken sounds differ from musical sounds properly so called, -in varying in pitch throughout their continuance. So far as -tone is concerned, apart from vowel quality, the speech note -may be imitated by sliding a finger up the finger-board -of a violin while the bow is being drawn. A familiar -illustration of the varying pitch of a speech note is found -in the utterance of Hamlet’s question, “Pale, or red?” with -intense anxiety of inquiry, if one may so speak. “The -speech note on the word ‘pale’ will consist of an upward -movement of the voice, while that on ‘red’ will be a downward -movement, and in both words the voice will traverse -an interval of pitch so wide as to be conspicuous to ordinary -ears; while the cultivated perception of the musician will -detect the voice moving through a less interval of pitch -while he is uttering the word ‘or’ of the same sentence. -And he who can record in musical notation the sounds -which he hears, will perceive the musical interval traversed -in these vocal movements, and the place also of these -speech notes on the musical staff.” Variations of this kind, -only not so great in amount, occur in ordinary speech; and -no telephonic or phonographic instrument could be regarded -as perfect, or even satisfactory, which did not reproduce them.</p> - -<p><span class="pagenum"><a id="Page_284">284</a></span> -But the vowel sounds are, after all, combinations and -modifications of musical tones. It is otherwise with consonantal -sounds, which, in reality, result from various ways -in which vowel sounds are commenced, interrupted (wholly -or partially), and resumed. In one respect this statement -requires, perhaps, some modification—a point which has not -been much noticed by writers on vocal sounds. In the case -of liquids, vowel sounds are not partially interrupted only, as -is commonly stated. They cease entirely as vowel sounds, -though the utterance of a vocal sound is continued when a -liquid consonant is uttered. Let the reader utter any word -in which a liquid occurs, and he will find that while the -liquid itself is sounded the vowel sounds preceding or -following the liquid cease entirely. Repeating slowly, for -example, the word “remain,” dwelling on all the liquids, we -find that while the “r” is being sounded the “ē” sound -cannot be given, and this sound ceases so soon as the “m” -is sounded; similarly the long “a” sound can only be -uttered when the “m” sound ceases, and cannot be carried -on into the sound of the final liquid “n.” The liquids are, -in fact, improperly called semi-vowels, since no vowel sound -can accompany their utterance. The tone, however, with -which they are sounded can be modified during their -utterance. In sounding labials the emission of air is not -stopped completely at any moment. The same is true of -the sibilants s, z, sh, zh, and of the consonants g, j, f, v, th -(hard and soft). These are called, on this account, <em>continuous</em> -consonants. The only consonants in pronouncing which -the emission of air is for a moment entirely stopped, are the -true mutes, sometimes called the six <em>explosive</em> consonants, -b, p, t, d, k, and g.</p> - -<p>To reproduce artificially sounds resembling those of the -consonants in speech, we must for a moment interrupt, -wholly for explosive and partially for continuous consonant -sounds, the passage of air through a reed pipe. Tyndall -thus describes an experiment of this kind in which an -imperfect imitation of the sound of the letter “m” was<span class="pagenum"><a id="Page_285">285</a></span> -obtained—an imitation only requiring, to render it perfect, -as I have myself experimentally verified, attention to the -consideration respecting liquids pointed out in the preceding -paragraph. “Here,” says Tyndall, describing the experiment -as conducted during a lecture, “is a free reed fixed in a -frame, but without any pipe associated with it, mounted on -the acoustic bellows. When air is urged through the orifice, -it speaks in this forcible manner. I now fix upon the frame -of the reed a pyramidal pipe; you notice a change in the -clang, and, by pushing my flat hand over the open end of -the pipe, the similarity between the sounds produced and -those of the human voice is unmistakable. Holding the -palm of my hand over the end of the pipe, so as to close it -altogether, and then raising my hand twice in quick succession, -the word ‘mamma’ is heard as plainly as if it were -uttered by an infant. For this pyramidal tube I now -substitute a shorter one, and with it make the same -experiment. The ‘mamma’ now heard is exactly such as -would be uttered by a child with a stopped nose. Thus, by -associating with a vibrating reed a suitable pipe, we can -impart to the sound of the reed the qualities of the human -voice.” The “m” obtained in these experiments was, however, -imperfect. To produce an “m” sound such as an -adult would utter without a “stopped nose,” all that is -necessary is to make a small opening (experiment readily -determines the proper size and position) in the side of the -pyramidal pipe, so that, as in the natural utterance of this -liquid, the emission of air is not altogether interrupted.</p> - -<p>I witnessed in 1874 some curious illustrations of the -artificial production of vocal sounds, at the Stevens Institute, -Hoboken, N.J., where the ingenious Professor Mayer (who -will have, I trust, a good deal to say about the scientific -significance of telephonic and phonographic experiments -before long) has acoustic apparatus, including several -talking-pipes. By suitably moving his hand on the top of -some of these pipes, he could make them speak certain words -with tolerable distinctness, and even utter short sentences.<span class="pagenum"><a id="Page_286">286</a></span> -I remember the performance closed with the remarkably -distinct utterance, by one profane pipe, of the words -euphemistically rendered by Mark Twain (in his story of the -Seven Sleepers, I think), “Go thou to Hades!”</p> - -<p>Now, the speaking diaphragm in the telephone, as in -the phonograph, presently to be described, must reproduce -not only all the varieties of sound-wave corresponding to -vowel sounds, with their intermixtures of the fundamental -tone and its overtones and their inflexions or sliding -changes of pitch, but also all the effects produced on the -receiving diaphragm by those interruptions, complete or -partial, of aerial emission which correspond to the pronunciation -of the various consonant sounds. It might certainly -have seemed hopeless, from all that had been before known -or surmised respecting the effects of aerial vibrations on -flexible diaphragms, to attempt to make a diaphragm speak -artificially—in other words, to make the movements of all -parts of it correspond with those of a diaphragm set in -vibration by spoken words—by movements affecting only -its central part. It is in the recognition of the possibility -of this, or rather in the discovery of the fact that the movements -of a minute portion of the middle of a diaphragm -regulate the vibratory and other movements of the entire -diaphragm, that the great scientific interest of Professor -Graham Bell’s researches appears to me to reside.</p> - -<p>It may be well, in illustration of the difficulties with -which formerly the subject appeared to be surrounded, to -describe the results of experiments which preceded, though -they can scarcely be said to have led up to, the invention -of artificial ways of reproducing speech. I do not now -refer to experiments like those of Kratzenstein of St. -Petersburg, and Von Kempelen of Vienna, in 1779, and -the more successful experiments by Willis in later years, -but to attempts which have been made to obtain material -records of the aerial motions accompanying the utterance -of spoken words. The most successful of these attempts -was that made by Mr. W. H. Barlow. His purpose was<span class="pagenum"><a id="Page_287">287</a></span> -“to construct an instrument which should record the pneumatic -actions” accompanying the utterance of articulated -sounds “by diagrams, in a manner analogous to that in -which the indicator-diagram of a steam-engine records the -action of the engine.” He perceived that the actual aerial -pressures involved being very small and very variable, and -the succession of impulses and changes of pressure being -very rapid, it was necessary that the moving parts should -be very light, and that the movement and marking should -be accomplished with as little friction as possible. The -instrument he constructed consisted of a small speaking-trumpet -about four inches long, having an ordinary mouthpiece -connected to a tube half an inch in diameter, the -thin end of which widened out so as to form an aperture -of 2¼ inches diameter. This aperture was covered with -a membrane of goldbeater’s skin, or thin gutta-percha. A -spring carrying a marker was made to press against the -membrane with a slight initial pressure, to prevent as far as -possible the effects of jarring and consequent vibratory -action. A light arm of aluminium was connected with the -spring, and held the marker; and a continuous strip of -paper was made to pass under the marker in the manner -employed in telegraphy. The marker consisted of a small, -fine sable brush, placed in a light tube of glass one-tenth of -an inch in diameter, the tube being rounded at the lower -end, and pierced with a hole about one-twentieth of an inch -in diameter. Through this hole the tip of the brush projected, -and was fed by colour put into the glass tube by -which it was held. It should be added that, to provide -for the escape of air passing through the speaking-trumpet, -a small opening was made in the side, so that the pressure -exerted upon the membrane was that due to the excess -of air forced into the trumpet over that expelled through -the orifice. The strength of the spring which carried the -marker was so adjusted to the size of the orifice that, while -the lightest pressures arising under articulation could be -recorded, the greatest pressures should not produce a movement -exceeding the width of the paper.</p> - -<p><span class="pagenum"><a id="Page_288">288</a></span> -“It will be seen,” says Mr. Barlow, “that in this construction -of the instrument the sudden application of -pressure is as suddenly recorded, subject only to the modifications -occasioned by the inertia, momentum, and friction -of the parts moved. But the record of the sudden cessation -of pressure is further affected by the time required to discharge -the air through the escape-orifice. Inasmuch, however, -as these several effects are similar under similar -circumstances, the same diagram should always be obtained -from the same pneumatic action when the instrument is -in proper adjustment; and this result is fairly borne out by -the experiments.”</p> - -<p>The defect of the instrument consisted in the fact that -it recorded changes of pressure only; and in point of -fact it seems to result, from the experiments made with it, -that it could only indicate the order in which explosive, -continuant, and liquid consonants succeeded each other in -spoken words, the vowels being all expressed in the same -way, and only one letter—the rough R, or R with a burr—being -always unmistakably indicated. The explosives were -represented by a sudden sharp rise and fall in the recorded -curve; the height of the rise depending on the strength -with which the explosive is uttered, not on the nature of the -consonant itself. Thus the word “tick” is represented -by a higher elevation for the “t” than for the “k,” but the -word “kite” by a higher elevation for the “k” than for -the “t.” It is noteworthy that there is always a second -smaller rise and fall after the first chief one, in the case -of each of the explosives. This shows that the membrane, -having first been forcibly distended by the small aerial explosion -accompanying the utterance of such a consonant, -sways back beyond the position where the pressure and -the elasticity of the membrane would (for the moment) -exactly balance, and then oscillates back again over that -position before returning to its undistended condition. -Sometimes a third small elevation can be recognized, and -when an explosive is followed by a rolling “r” several<span class="pagenum"><a id="Page_289">289</a></span> -small elevations are seen. The continuous consonants produce -elevations less steep and less high; aspirates and -sibilants give rounded hills. But the results vary greatly -according to the position of a consonant; and, so far as I -can make out from a careful study of the very interesting -diagrams accompanying Mr. Barlow’s paper, it would be -quite impossible to define precisely the characteristic records -even of each order of consonantal sounds, far less of each -separate sound.</p> - -<p>We could readily understand that the movement of the -central part of the diaphragm in the telephone should give -much more characteristic differences for the various sounds -than Barlow’s logograph. For if we imagine a small pointer -attached to the centre of the face of the receiving diaphragm -while words are uttered in its neighbourhood, the end of -that pointer would not only move to and fro in a direction -square to the face of the diaphragm, as was the case with -Barlow’s marker, but it would also sway round its mean -position in various small circles or ovals, varying in size, -shape, and position, according to the various sounds uttered. -We might expect, then, that if in any way a record of the -actual motions of the extremity of that small pointer could -be obtained, in such sort that its displacement in directions -square to the face of the diaphragm, as well as its swayings -around its mean position, would be indicated in some -pictorial manner, the study of such records would indicate -the exact words spoken near the diaphragm, and even, -perhaps, the precise tones in which they were uttered. For -Barlow’s logograph, dealing with one only of the orders -of motion (really triple in character), gives diagrams in -which the general character of the sounds uttered is clearly -indicated, and the supposed records would show much -more.</p> - -<p>But although this might, from <i xml:lang="la" lang="la">à priori</i> considerations, -have been reasonably looked for, it by no means follows -that the actual results of Bell’s telephonic experiments could -have been anticipated. That the movement of the central<span class="pagenum"><a id="Page_290">290</a></span> -part of the diaphragm should suffice to show that such and -such words had been uttered, is one thing; but that these -movements should of themselves suffice, if artificially reproduced, -to cause the diaphragm to reproduce these words, -is another and a very different one. I venture to express -my conviction that at the beginning of his researches Professor -Bell can have had very little hope that any such -result would be obtained, notwithstanding some remarkable -experiments respecting the transmission of sound which we -can <em>now</em> very clearly perceive to point in that direction.</p> - -<p>When, however, he had invented the telephone, this -point was in effect demonstrated; for in that instrument, as -we have seen, the movements of the minute piece of metal -attached (at least in the earlier forms of the instrument) to -the centre of the receiving membrane, suffice, when precisely -copied by the similar central piece of metal in the transmitting -membrane, to cause the words which produced the -motions of the receiving or hearing membrane to be uttered -(or seem to be uttered) by the transmitting or speaking -membrane.</p> - -<p>It was reserved, however, for Edison (of New Jersey, -U.S.A., Electrical Adviser to the Western Union Telegraph -Company) to show how advantage might be taken of this -discovery to make a diaphragm speak, not directly through -the action of the movements of a diaphragm affected by -spoken words or other sounds, and therefore either simultaneously -with these or in such quick succession after them -as corresponds with the transmission of their effects along -some line of electrical or other communication, but by -the mechanical reproduction of similar movements at any -subsequent time (within certain limits at present, but probably -hereafter with practically unlimited extension as to -time).</p> - -<p>The following is slightly modified from Edison’s own -description of the phonograph:—</p> - -<p>The instrument is composed of three parts mainly; -namely, a receiving, a recording, and a transmitting apparatus.<span class="pagenum"><a id="Page_291">291</a></span> -The receiving apparatus consists of a curved tube, -one end of which is fitted with a mouthpiece. The other -end is about two inches in diameter, and is closed with a -disc or diaphragm of exceedingly thin metal, capable of -being thrust slightly outwards or vibrated upon gentle -pressure being applied to it from within the tube. To the -centre of this diaphragm (which is vertical) is fixed a small -blunt steel pin, which shares the vibratory motion of the -diaphragm. This arrangement is set on a table, and can be -adjusted suitably with respect to the second part of the -instrument—the recorder. This is a brass cylinder, about -four inches in length and four in diameter, cut with a continuous -V-groove from one end to the other, so that in effect -it represents a large screw. There are forty of these grooves -in the entire length of the cylinder. The cylinder turns -steadily, when the instrument is in operation, upon a vertical -axis, its face being presented to the steel point of the receiving -apparatus. The shaft on which it turns is provided with -a screw-thread and works in a screwed bearing, so that as -the shaft is turned (by a handle) it not only turns the -cylinder, but steadily carries it upwards. The rate of this -vertical motion is such that the cylinder behaves precisely -as if its groove worked in a screw-bearing. Thus, if the -pointer be set opposite the middle of the uppermost part of -the continuous groove at the beginning of this turning motion, -it will traverse the groove continuously to its lowest -part, which it will reach after forty turnings of the handle. -(More correctly, perhaps, we might say that the groove continuously -traverses past the pointer.) Now, suppose that a -piece of some such substance as tinfoil is wrapped round -the cylinder. Then the pointer, when at rest, just touches -the tinfoil. But when the diaphragm is vibrating under the -action of aerial waves resulting from various sounds, the -pointer vibrates in such a way as to indent the tinfoil—not -only to a greater or less depth according to the play of the -pointer to and fro in a direction square to the face of the -diaphragm, but also over a range all round its mean position,<span class="pagenum"><a id="Page_292">292</a></span> -corresponding to the play of the end of the pointer around -<em>its</em> mean position. The groove allows the pressure of the -pointer against the tinfoil free action. If the cylinder had -no groove the dead resistance of the tinfoil, thus backed up -by an unyielding surface, would stop the play of the pointer. -Under the actual conditions, the tinfoil is only kept taut -enough to receive the impressions, while yielding sufficiently -to let the play of the pointer continue unrestrained. If now -a person speaks into the receiving tube, and the handle of -the cylinder be turned, the vibrations of the pointer are impressed -upon the portion of the tinfoil lying over the hollow -groove, and are retained by it. They will be more or less -deeply marked according to the quality of the sounds -emitted, and according also, of course, to the strength with -which the speaker utters the sounds, and to the nature of -the modulations and inflexions of his voice. The result is -a message verbally imprinted upon a strip of metal. It -differs from the result in the case of Barlow’s logograph, in -being virtually a record in three dimensions instead of one -only. The varying depth of the impressions corresponds to -the varying height of the curve in Barlow’s diagrams; but -there the resemblance ceases; for that was the single feature -which Barlow’s logographs could present. Edison’s imprinted -words show, besides varying depth of impression, a -varying range on either side of the mean track of the pointer, -and also—though the eye is not able to detect this effect—there -is a varying rate of progression according as the end -of the pointer has been swayed towards or from the direction -in which, owing to the motion of the cylinder, the pointer is -virtually travelling.</p> - -<p>We may say of the record thus obtained that it is sound -presented in a visible form. A journalist who has written -on the phonograph has spoken of this record as corresponding -to the crystallization of sound. And another who, like -the former, has been (erroneously, but that is a detail) -identified with myself, has said, in like fanciful vein, that the -story of Baron Münchausen hearing words which had been<span class="pagenum"><a id="Page_293">293</a></span> -frozen during severe cold melting into speech again, so that -all the babble of a past day came floating about his ears, -has been realized by Edison’s invention. Although such -expressions may not be, and in point of fact are not, strictly -scientific, I am not disposed, for my own part, to cavil with -them. If they could by any possibility be taken <i xml:lang="fr" lang="fr">au pied de -la lettre</i> (and, by the way, we find quite a new meaning for -this expression in the light of what is now known about -vowels and consonants), there would be valid objection to -their use. But, as no one supposes that Edison’s phonograph -really crystallizes words or freezes sounds, it seems -hypercritical to denounce such expressions as the critic -of the <cite>Telegraphic Journal</cite> has denounced them.</p> - -<p>To return to Edison’s instrument.</p> - -<p>Having obtained a material record of sounds, vocal or -otherwise, it remains that a contrivance should be adopted -for making this record reproduce the sounds by which it was -itself formed. This is effected by a third portion of the -apparatus, the transmitter. This is a conical drum, or rather -a drum shaped like a frustum of a cone, having its larger -end open, the smaller—which is about two inches in -diameter—being covered with paper stretched tight like the -parchment of a drumhead. In front of this diaphragm is a -light flat steel spring, held vertically, and ending in a blunt -steel point, which projects from it and corresponds precisely -with that on the diaphragm of the receiver. The spring is -connected with the paper diaphragm by a silken thread, just -sufficiently in tension to cause the outer face of the -diaphragm to be slightly convex. Having removed the -receiving apparatus from the cylinder and set the cylinder -back to its original position, the transmitting apparatus is -brought up to the cylinder until the steel point just rests, -without pressure, in the first indentation made in the tinfoil -by the point of the receiver. If now the handle is turned at -the same speed as when the message was being recorded, -the steel point will follow the line of impression, and will -vibrate in periods corresponding to the impressions which<span class="pagenum"><a id="Page_294">294</a></span> -were produced by the point of the receiving apparatus. The -paper diaphragm being thus set into vibrations of the requisite -kind in number, depth, and side-range, there are produced -precisely the same sounds that set the diaphragm of -the receiver into vibration originally. Thus the words of -the speaker are heard issuing from the conical drum in his -own voice, tinged with a slightly metallic or mechanical tone. -If the cylinder be more slowly turned when transmitting than -it had been when receiving the message, the voice assumes -a base tone; if more quickly, the message is given with a -more treble voice. “In the present machine,” says the -account, “when a long message is to be recorded, so soon -as one strip of tinfoil is filled, it is removed and replaced by -others, until the communication has been completed. In -using the machine for the purpose of correspondence, the -metal strips are removed from the cylinder and sent to the -person with whom the speaker desires to correspond, who -must possess a machine similar to that used by the sender. -The person receiving the strips places them in turn on the -cylinder of his apparatus, applies the transmitter, and puts -the cylinder in motion, when he hears his friend’s voice -speaking to him from the indented metal. And he can repeat -the contents of the missive as often as he pleases, until -he has worn the metal through. The sender can make an -infinite number of copies of his communication by taking a -plaster-of-Paris cast of the original, and rubbing off impressions -from it on a clean sheet of foil.”</p> - -<p>I forbear from dwelling further on the interest and value -of this noble invention, or of considering some of the -developments which it will probably receive before long, -for already I have occupied more space than I had intended. -I have no doubt that in these days it will bring its inventor -less credit, and far less material gain, than would be acquired -from the invention of some ingenious contrivance for destroying -many lives at a blow, bursting a hole as large as a church -door in the bottom of an ironclad, or in some other way -helping men to carry out those destructive instincts which<span class="pagenum"><a id="Page_295">295</a></span> -they inherit from savage and brutal ancestors. But hereafter, -when the representatives of the brutality and savagery -of our nature are held in proper disesteem, and those who -have added new enjoyments to life are justly valued, a high -place in the esteem of men will be accorded to him who has -answered one-half of the poet’s aspiration,</p> - -<div class="poem-container"> -<div class="poem"><div class="stanza"> -<span class="iq">“Oh for the touch of a vanished hand,<br /></span> -<span class="i0">And the sound of a voice that is still!”<br /></span> -</div></div> -</div> - -<div class="tb">* <span class="in2">* </span><span class="in2">* </span><span class="in2">* </span><span class="in2">*</span></div> - -<p><span class="smcap">Note.</span>—Since the present paper was written, M. Aurel de Ratti has -made some experiments which he regards as tending to show that there -is no mechanical vibration. Thus, “when the cavities above and below -the iron disc of an ordinary telephone are filled with wadding, the -instrument will transmit and speak with undiminished clearness. On -placing a finger on the iron disc opposite the magnet, the instrument -will transmit and speak distinctly, only ceasing to act when sufficient -pressure is applied to bring plate and magnet into contact. Connecting -the centre of the disc by means of a short thread with an extremely -sensitive membrane, no sound is given out by the latter when a message -is transmitted. Bringing the iron cores of the double telephone in contact -with the disc, and pressing with the fingers against the plate on the -other side, a weak current from a Daniell cell produced a distinct click -in the plate, and on drawing a wire from the cell over a file which -formed part of the circuit, a rattling noise was produced in the instrument.” -If these experiments had been made before the phonograph -was invented, they would have suggested the impracticability of constructing -any instrument which would do what the phonograph actually -does, viz., cause sounds to be repeated by exciting a merely mechanical -vibration of the central part of a thin metallic disc. But as the phonograph -proves that this can actually be done, we must conclude that M. -Aurel de Ratti’s experiments will not bear the interpretation he places -upon them. They show, nevertheless, that exceedingly minute vibrations -of probably a very small portion of the telephonic disc suffice for -the distinct transmission of vocal sounds. This might indeed be inferred -from the experiments of M. Demozet, of Nantes, who finds that the -vibrations of the transmitting telephone are in amplitude little more than -1-2000th those of the receiving telephone.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_296">296</a></span></p> - -<div class="chapter"> -<h2><a id="THE_GORILLA_AND_OTHER_APES"></a><i>THE GORILLA AND OTHER APES.</i></h2> -</div> - -<p class="in0">About twenty-five centuries ago, a voyager called Hanno is -said to have sailed from Carthage, between the Pillars of -Hercules—that is, through the Straits of Gibraltar—along -the shores of Africa. “Passing the Streams of Fire,” says -the narrator, “we came to a bay called the Horn of the -South. In the recess there was an island, like the first, -having a lake, and in this there was another island full of -wild men. But much the greater part of them were women, -with hairy bodies, whom the interpreters called ‘Gorillas.’ -Pursuing them, we were not able to take the men; -they all escaped, being able to climb the precipices; -and defended themselves with pieces of rock. But three -women, who bit and scratched those who led them, were -not willing to follow. However, having killed them, we -flayed them, and conveyed the skins to Carthage; for we -did not sail any further, as provisions began to fail.”<a id="FNanchor_35" href="#Footnote_35" class="fnanchor">35</a></p> - -<p>In the opinion of many naturalists, the wild men of -this story were the anthropoid or manlike apes which are -now called gorillas, rediscovered recently by Du Chaillu. -The region inhabited by the gorillas is a well-wooded -country, “extending about a thousand miles from the Gulf -of Guinea southward,” says Gosse; “and as the gorilla is -not found beyond these limits, so we may pretty conclusively -infer that the extreme point of Hanno was somewhere<span class="pagenum"><a id="Page_297">297</a></span> -in this region.” I must confess these inferences seem -to me somewhat open to question, and the account of -Hanno’s voyage only interesting in its relation to the gorilla, -as having suggested the name now given to this race of -apes. It is not probable that Hanno sailed much further -than Sierra Leone; according to Rennell, the island where -the “wild men” were seen, was the small island lying -close to Sherbro, some seventy miles south of Sierra Leone. -To have reached the gorilla district after doubling Cape -Verd—which is itself a point considerably south of the -most southerly city founded by Hanno—he would have had -to voyage a distance exceeding that of Cape Verd from -Carthage. Nothing in the account suggests that the portion -of the voyage, after the colonizing was completed, had so -great a range. The behaviour of the “wild men,” again, -does not correspond with the known habits of the gorilla. -The idea suggested is that of a species of anthropoid ape -far inferior to the gorilla in strength, courage, and ferocity.</p> - -<p>The next accounts which have been regarded as relating -to the gorilla are those given by Portuguese voyagers. -These narratives have been received with considerable -doubt, because in some parts they seem manifestly fabulous. -Thus the pictures representing apes show also huge flying -dragons with a crocodile’s head; and we have no reason -for believing that batlike creatures like the pterodactyls of -the greensand existed in Africa or elsewhere so late as the -time of the Portuguese voyages of discovery. Purchas, in -his history of Andrew Battell, speaks of “a kinde of great -apes, if they might so bee termed, of the height of a man, -but twice as bigge in feature of their limmes, with strength -proportionable, hairie all over, otherwise altogether like men -and women in their whole bodily shape, except that their -legges had no calves.” This description accords well with -the peculiarities of gorillas, and may be regarded as the -first genuine account of these animals. Battell’s contemporaries -called the apes so described Pongoes. It is probable -that in selecting the name Pongo for the young<span class="pagenum"><a id="Page_298">298</a></span> -gorilla lately at the Westminster Aquarium, the proprietors -of this interesting creature showed a more accurate -judgment of the meaning of Purchas’s narrative than Du -Chaillu showed of Hanno’s account, in calling the great -anthropoid ape of the Gulf of Guinea a gorilla.</p> - -<p>I propose here briefly to sketch the peculiarities of the -four apes which approach nearest in form to man—the -gorilla, the chimpanzee, the orang-outang, and the gibbon; -and then, though not dealing generally with the question -of our relationship to these non-speaking (and, in some -respects, perhaps, “unspeakable”) animals, to touch on -some points connected with this question, and to point out -some errors which are very commonly entertained on the -subject.</p> - -<p>It may be well, in the first place, to point out that the -terms “ape,” “baboon,” and “monkey” are no longer -used as they were by the older naturalists. Formerly the -term “ape” was limited to tailless simians having no cheek-pouches, -and the same number of teeth as man; the term -“baboon” to short-tailed simians with dog-shaped heads; -and the term “monkey,” unless used generically, to the -long-tailed species. This was the usage suggested by Ray, -and adopted systematically thirty or forty years ago. But -it is no longer followed, though no uniform classification -has been substituted for the old arrangement. Thus Mivart -divides the apes into two classes—calling the first the -<i>Simiadæ</i>, or Old World apes; and the second the <i>Cebidæ</i>, -or New World apes. He subdivides the <i>Simiadæ</i> into (1) -the <i>Siminæ</i>, including the gorilla, chimpanzee, orang, and -gibbon; (2) the <i>Semnopithecinæ</i>; and (3) the <i>Cynopithecinæ</i>; -neither of which subdivisions will occupy much of our -attention here, save as respects the third subdivision of -the <i>Cynopithecinæ</i>, viz., the <i>Cynocephali</i>, which includes the -baboons. The other great division, the <i>Cebidæ</i>, or New -World apes, are for the most part very unlike the Old -World apes. None of them approach the gorilla or orang-outang -in size; most of them are long-tailed; and the<span class="pagenum"><a id="Page_299">299</a></span> -number and arrangement of the teeth is different. The -feature, however, which most naturalists have selected as -the characteristic distinction between the apes of the Old -World and of the New World is the position of the nostrils. -The former are called Catarhine, a word signifying that the -nostrils are directed downwards; the latter are called -Platyrhine, or broad-nosed. The nostrils of all the Old -World apes are separated by a narrow cartilaginous plate -or septum, whereas the septum of the New World apes is -broad. After the apes come, according to Mivart’s classification, -the half-apes or lemuroids.</p> - -<p>I ought, perhaps, to have mentioned that Mivart, in -describing the lemuroids as the second sub-order of a great -order of animals, the Primates, speaks of a man as (zoologically -speaking) belonging to the first sub-order. So that, -in point of fact, the two sub-orders are the Anthropoids, -including the Anthropos (man) and the Lemuroids, including -the lemur.</p> - -<p>The classification here indicated will serve our present -purpose very well. But the reader is reminded that, as -already mentioned, naturalists do not adopt at present any -uniform system of classification. Moreover, the term -<i>Simiadæ</i> is usually employed—and will be employed here—to -represent the entire simian race, <i>i.e.</i>, both the Simiadæ -and the Cebidæ of Mivart’s classification.</p> - -<p>And now, turning to the Anthropoid apes, we find ourselves -at the outset confronted by the question, Which of -the four apes, the gorilla, the orang-outang, the chimpanzee, -or the gibbon, is to be regarded as nearest to man in intelligence? -So far as bodily configuration is concerned, our -opinion would vary according to the particular feature which -we selected for consideration. But it will probably be -admitted that intelligence should be the characteristic by -which our opinions should be guided.</p> - -<p>The gibbon may be dismissed at once, though, as will -presently appear, there are some features in which this ape -resembles man more closely than either the gorilla, the orang-outang, -or the chimpanzee.</p> - -<p><span class="pagenum"><a id="Page_300">300</a></span> -The gorilla must, I fear, be summarily ejected from the -position of honour to which he has been raised by many -naturalists. Though the gorilla is a much larger animal -than the chimpanzee, his brain barely equals the chimpanzee’s -in mass. It is also less fully developed in front. -In fact Gratiolet asserts that of all the broad-chested apes, -the gorilla is—so far as brain character is concerned—the -lowest and most degraded. He regards the gorilla’s brain -as only a more advanced form of that of the brutal baboons, -while the orang’s brain is the culminating form of the gibbon -type, and the chimpanzee’s the culminating form of the -macaque type. This does not dispose of the difficulty very -satisfactorily, however, because it remains to be shown -whether the gibbon type and the macaque type are superior -as types to the baboon types. But it may suffice to remark -that the baboons are all brutal and ferocious, whereas the -gibbons are comparatively gentle animals, and the macaques -docile and even playful. It may be questioned whether -brutality and ferocity should be regarded as necessarily -removing the gorilla further from man; because it is certain -that the races of man which approach nearest to the anthropoid -apes, with which races the comparison should -assuredly be made, are characterized by these very qualities, -brutality and ferocity. Intelligence must be otherwise -gauged. Probably the average proportion of the brain’s -weight to that of the entire body, and the complexity of -the structure of the brain, would afford the best means of -deciding the question. But, unfortunately, we have very -unsatisfactory evidence on these points. The naturalists -who have based opinions on such evidence as has been -obtained, seem to overlook the poverty of the evidence. -Knowing as we do how greatly the human brain varies in -size and complexity, not only in different races, but in -different individuals of the same race, it appears unsatisfactory -in the extreme to regard the average of the -brains of each simian species hitherto examined as presenting -the true average cerebral capacity for each species.</p> - -<p><span class="pagenum"><a id="Page_301">301</a></span> -Still it seems tolerably clear that the choice as to the race -of apes which must be regarded as first in intelligence, and -therefore as on the whole the most manlike, rests between -the orang-outang and the chimpanzee. “In the world of -science, as in that of politics,” said Professor Rolleston in -1862, “France and England have occasionally differed as to -their choice between rival candidates for royalty. If either -hereditary claims or personal merits affect at all the right of -succession, beyond a question the gorilla is but a pretender, -and one or other of the two (other) candidates the true -prince. There is a graceful as well as an ungraceful way of -withdrawing from a false position, and the British public will -adopt the graceful course by accepting forthwith and henceforth -the French candidate”—the orang-outang. If this -were intended as prophecy, it has not been fulfilled by the -event, for the gorilla is still regarded by most British naturalists -as the ape which comes on the whole nearest to man; -but probably, in saying “the British public will adopt the -graceful course” in accepting the orang-outang as “the king -of the Simiadæ,” Professor Rolleston meant only that that -course would be graceful if adopted.</p> - -<p>Before the discovery of the gorilla, the chimpanzee was -usually regarded as next to man in the scale of the animal -creation. It was Cuvier who first maintained the claim of -the orang-outang to this position. Cuvier’s opinion was -based on the greater development of the orang-outang’s -brain, and the height of its forehead. But these marks of -superiority belong to the orang only when young. The -adult orang seems to be inferior, or at least not superior, to -the chimpanzee as respects cerebral formation, and in other -respects seems less to resemble man. The proportions of -his body, his long arms, high shoulders, deformed neck, and -imperfect ears are opposed to its claims to be regarded as -manlike. In all these respects, save one, the chimpanzee -seems to be greatly its superior. (The ear of the chimpanzee -is large, and not placed as with us: that of the gorilla is -much more like man’s.)</p> - -<p><span class="pagenum"><a id="Page_302">302</a></span> -As to the intelligence exhibited in the conduct of the -chimpanzee and orang-outang, various opinions may be -formed according to the various circumstances under which -the animals are observed. The following has been quoted -in evidence of the superiority of the chimpanzee in this -respect:—“About fifty years ago, a young chimpanzee and -an orang-outang of about the same age were exhibited -together at the Egyptian Hall. The chimpanzee, though in -a declining state of health, and rendered peevish and -irritable by bodily suffering, exhibited much superior marks -of intelligence to his companion; he was active, quick, and -observant of everything that passed around him; no new -visitor entered the apartment in which he was kept, and no -one left it, without attracting his attention. The orang-outang, -on the contrary, exhibited a melancholy and a disregard -of passing occurrences almost amounting to apathy; -and though in the enjoyment of better health, was evidently -much inferior to his companion in quickness and observation. -On one occasion, when the animals were dining on -potatoes and boiled chicken, and surrounded as usual with -a large party of visitors, the orang-outang allowed her plate -to be taken without exhibiting the least apparent concern. -Not so, however, the chimpanzee. We took advantage of -an opportunity when his head was turned (to observe a -person coming in) to secrete his plate also. For a few -seconds he looked round to see what had become of it, but, -not finding it, began to pout and fret exactly like a spoiled -child, and perceiving a young lady, who happened to be -standing near him, laughing, perhaps suspecting her to be the -delinquent, he flew at her in the greatest rage, and would -probably have bitten her had she not got beyond his reach. -Upon having his plate restored, he took care to prevent the -repetition of the joke by holding it firmly with one hand, -while he fed himself with the other.”</p> - -<p>This story can hardly be regarded as deciding the question -in favour of the chimpanzee. Many animals, admittedly -far inferior to the lowest order of monkeys in intelligence,<span class="pagenum"><a id="Page_303">303</a></span> -show watchfulness over their food, and as much ill-temper -when deprived of it, and as much anxiety to recover it, as -this chimpanzee did. A hundred cases in point might -readily be cited.<a id="FNanchor_36" href="#Footnote_36" class="fnanchor">36</a></p> - -<p>Perhaps the soundest opinion respecting the relative -position of the gorilla, chimpanzee, and orang-outang with -reference to man, is that which places the gorilla nearest to -the lower tribes of man now inhabiting Africa, the chimpanzee -approximating, but not so closely, to higher African -tribes, and the orang-outang approximating, but still less -closely, to Asiatic tribes. It appears to me that, whatever -weight naturalists may attach to those details in which the -gorilla and the chimpanzee are more removed from man -than the orang, no one who takes a <em>general</em> view of these -three races of anthropoid apes can hesitate to regard the -gorilla as that which, on the whole, approaches nearest to -man; but it is to a much lower race of man that the gorilla -approximates, so that the chimpanzee and the orang-outang -may fairly be regarded as higher in the scale of animal life.</p> - -<p>If we consider young specimens of the three animals, -which is, on the whole, the safest way of forming an opinion, -we are unmistakably led, in my judgment, to such a conclusion. -I have seen three or four young chimpanzees, two -young orangs, and the young gorilla lately exhibited at the -Aquarium (where he could be directly compared with the -chimpanzee), and I cannot hesitate to pronounce Pongo<span class="pagenum"><a id="Page_304">304</a></span> -altogether the most human of the three. A young chimpanzee -reminds one rather of an old man than of a child, -and the same may be said of young orangs; but the young -gorilla unmistakably reminds one of the young negro. -Repeatedly, while watching Pongo, I was reminded of the -looks and behaviour of young negroes whom I had seen in -America, though not able in every case to fix definitely -on the feature of resemblance which recalled the negro to -my mind. (The reader is, doubtless, familiar with half-remembered -traits such as those I refer to—traits, for -instance, such as assure you that a person belongs to some -county or district, though you may be unable to say what -feature, expression, or gesture suggests the idea.) One circumstance -may be specially noted, not only as frequently recurring, -but as illustrating the traits on which the resemblance -of the gorilla (when young, at any rate) to the negro depends. -A negro turns his eyes where a Caucasian would turn his -head. The peculiarity is probably a relic of savage life; for -the savage, whether engaged in war or in the chase, avoids, -as far as possible, every movement of body or limb. Pongo -looked in this way. When he thus cast his black eyes -sideways at an object I found myself reminded irresistibly -of the ways of the watchful negro waiters at an American -hotel. Certainly there is little in the movements of the -chimpanzee to remind one of any kind of human child. He -is impish; but not the most impish child of any race or tribe -ever had ways, I should suppose, resembling his.</p> - -<p>The four anthropoid apes, full grown and in their native -wilds, differ greatly from each other in character. It may -be well to consider their various traits, endeavouring to -ascertain how far diversities existing among them may be -traced to the conditions under which the four orders subsist.</p> - -<p>The gorilla occupies a well-wooded country extending -along the coast of Africa from the Gulf of Guinea southwards -across the equator. When full grown he is equal to a man -in height, but much more powerfully built. “Of specimens -shot by Du Chaillu,” says Rymer Jones, “the largest male<span class="pagenum"><a id="Page_305">305</a></span> -seems to have been at least six feet two in height; so that, -making allowance for the shortness of the lower limbs, the -dimensions of a full-grown male may be said to equal those -of a man of eight or nine feet high, and it is only in their -length that the lower limbs are disproportionate to the -gigantic trunk. In the thickness and solidity of their bones, -and in the strength of their muscles, these limbs are quite in -keeping with the rest of the body. When upright, the -gorilla’s arms reach to his knees; the hind hands are wide, -and of amazing size and power; the great toe or thumb -measures six inches in circumference; the palms and soles, -and the naked part of the face, are of an intense black -colour, as is also the breast. The other parts are thickly -clothed with hair of an iron grey, except the head, on which -it is reddish brown, and the arms, where it is long and nearly -black. The female is wholly tinged with red.”</p> - -<p>Du Chaillu gives the following account of the aspect of -the gorilla in his native woods:—“Suddenly, as we were yet -creeping along in a silence which made even a heavy breath -seem loud and distinct, the woods were at once filled with a -tremendous barking roar; then the underbrush swayed -rapidly just ahead, and presently stood before us an immense -gorilla. He had gone through the jungle on all-fours; but -when he saw our party he erected himself and looked us -boldly in the face. He stood about a dozen yards from us, -and was a sight I think I shall never forget. Nearly six feet -high (he proved four inches shorter), with immense body, -huge chest, and great muscular arms, with fiercely glaring, -large, deep-grey eyes, and a hellish expression of face, which -seemed to me some night-mare vision; thus stood before us -the king of the African forest. He was not afraid of us; he -stood there and beat his breasts with his large fists till it -resounded like an immense bass drum (which is their mode -of bidding defiance), meantime giving vent to roar after roar.”</p> - -<p>The gorilla is a fruit-eater, but as fierce as the most -carnivorous animals. He is said to show an enraged enmity -against men, probably because he has found them not only<span class="pagenum"><a id="Page_306">306</a></span> -hostile to himself, but successful in securing the fruits which -the gorilla loves, for he shows a similar hatred to the -elephant, which also seeks these fruits. We are told that -when the gorilla “sees the elephant busy with his trunk -among the twigs, he instantly regards this as an infraction of -the laws of property, and, dropping silently down to the -bough, he suddenly brings his club smartly down on the -sensitive finger of the elephant’s proboscis, and drives off -the alarmed animal trumpeting shrilly with rage and pain.” -His enmity to man is more terribly manifested. “The -young athletic negroes in their ivory-haunts,” says Gosse, -“well know the prowess of the gorilla. He does not, like -the lion, sullenly retreat on seeing them, but swings himself -rapidly down to the lower branches, courting the conflict, -and clutches the nearest of his enemies. The hideous -aspect of his visage (his green eyes flashing with rage) is -heightened by the thick and prominent brows being drawn -spasmodically up and down, with the hair erect, causing a -horrible and fiendish scowl. Weapons are torn from their -possessor’s grasp, gun-barrels bent and crushed in by the -powerful hands and vice-like teeth of the enraged brute. -More horrid still, however, is the sudden and unexpected -fate which is often inflicted by him. Two negroes will be -walking through one of the woodland paths unsuspicious of -evil, when in an instant one misses his companion, or turns -to see him drawn up in the air with a convulsed choking -cry, and in a few minutes dropped to the ground, a strangled -corpse. The terrified survivor gazes up, and meets the grin -and glare of the fiendish giant, who, watching his opportunity, -had suddenly put down his immense hind hand, -caught the wretch by the neck with resistless power, and -dropped him only when he ceased to struggle.”</p> - -<p>The chimpanzee inhabits the region from Sierra Leone -to the southern confines of Angola, possibly as far as Cape -Negro, so that his domain includes within it that of the -gorilla. He attains almost the same height as the gorilla -when full grown, but is far less powerfully built. In fact, in<span class="pagenum"><a id="Page_307">307</a></span> -general proportions the chimpanzee approaches man more -nearly than does any other animal. His body is covered -with long black coarse hair, thickest on the head, shoulders, -and back, and rather thin on the breast and belly. The -face is dark brown and naked, as are the ears, except that -long black whiskers adorn the animal’s cheeks. The hair -on the forearms is directed towards the elbows, as is the case -with all the anthropoid apes, and with man himself. This -hair forms, where it meets the hair from the upper arm, a -small ruff about the elbow joint. The chimpanzees live in -society in the woods, constructing huts from the branches -and foliage of trees to protect themselves against the sun -and heavy rains. It is said by some travellers that the -chimpanzee walks upright in its native woods, but this is -doubtful; though certainly the formation of the toes better -fits them to stand upright than either the gorilla or the orang. -They arm themselves with clubs, and unite to defend themselves -against the attacks of wild beasts, “compelling,” it is -said, “even the elephant himself to abandon the districts in -which they reside.” We learn that “it is dangerous for men -to enter their forests, unless in companies and well armed; -women in particular are often said to be carried away by -these animals, and one negress is reported to have lived -among them for the space of three years, during which time -they treated her with uniform kindness, but always prevented -any attempt on her part to escape. When the negroes -leave a fire in the woods, it is said that the chimpanzees will -gather round and warm themselves at the blaze, but they -have not sufficient intelligence to keep it alive by fresh -supplies of fuel.”</p> - -<p>The orang-outang inhabits Borneo, Java, Sumatra, and -other islands of the Indian coast. He attains a greater -height than the gorilla, but, though very powerful and active, -would probably not be a match for the gorilla in a single -combat. His arms are by comparison as well as actually -much longer. Whereas the gorilla’s reach only to the knees, -the arms of the orang-outang almost reach the ground when<span class="pagenum"><a id="Page_308">308</a></span> -the animal is standing upright. The orang does not often -assume an upright attitude, however. “It seldom attempts -to walk on the hind feet alone, and when it does the hands -are invariably employed for the purpose of steadying its -tottering equilibrium, touching the ground lightly on each -side as it proceeds, and by this means recovering the lost -balance of the body.” The gorilla uses his hands differently. -He can scarcely be said to walk on all-fours, because he -does not place the inside of the hand on the ground, but -walks on the knuckles, evidently trying to keep the fore part -of the body as high as possible. “The muzzle is somewhat -long, the mouth ill-shaped, the lips thin and protuberant; -the ears are very small, the chin scarcely recognizable, and -the nose only to be recognized by the nostrils. The face, -ears, and inside of the hands of the orang are naked and of -a brick-red colour; the fore parts are also but thinly covered -with hair; but the head, shoulders, back, and extremities -are thickly clothed with long hair of dark wine-red colour, -directed forwards on the crown of the head and upwards -towards the elbows on the forearms.”</p> - -<p>The orang-outang changes remarkably in character and -appearance as he approaches full growth. “Though exhibiting -in early youth a rotundity of the cranium and a height of -forehead altogether peculiar, and accompanied at the same -time with a gentleness of disposition and a gravity of -manners which contrast strongly with the petulant and -irascible temper of the lower orders of quadrumanous mammals, -the orang-outang in its adult state is even remarkable -for the flatness of its retiring forehead, the great development -of the superorbital and occipital crests, the prominence -of its jaws, the remarkable size of its canine teeth, and the -whole form of the skull, which from the globular shape of -the human head, as in the young specimen, assumes all the -forms and characters belonging to that of a large carnivorous -animal. The extraordinary contrasts thus presented in the -form of the skull at different epochs of the same animal’s -life were long considered as the characters of distinct species;<span class="pagenum"><a id="Page_309">309</a></span> -nor was it till intermediate forms were obtained, exhibiting -in some degree the peculiarities of both extremes, that they -were finally recognized as distinguishing different periods of -growth only.”</p> - -<p>Unlike the gorilla, which attacks man with peculiar -malignity, and the chimpanzee, which when in large troops -assails those who approach its retreats, the orang, even in -its adult state, seems not to be dangerous unless attacked. -Even then he does not always show great ferocity. The -two following anecdotes illustrate well its character. The -first is from the pen of Dr. Abel Clarke (fifth volume of the -“Asiatic Researches”); the other is from Wallace’s interesting -work, “The Malay Archipelago.” An orang-outang -fully seven feet high was discovered by the company of a -merchant ship, at a place called Ramboon, on the north-west -coast of Sumatra, on a spot where there were few trees -and little cultivated ground. “It was evident that he had -come from a distance, for his legs were covered with mud up -to the knees, and the natives were unacquainted with him. -On the approach of the boat’s crew he came down from the -tree in which he was discovered, and made for a clump at -some distance; exhibiting, as he moved, the appearance of -a tall man-like figure, covered with shining brown hair, -walking erect, with a waddling gait, but sometimes accelerating -his motion with his hands, and occasionally impelling -himself forward with the bough of a tree. His motion on -the ground was evidently not his natural mode of progression, -for, even when assisted by his hands and the bough, it was -slow and vacillating; it was necessary to see him among the -trees to estimate his strength and agility. On being driven -to a small clump, he gained by one spring a very lofty -branch and bounded from one branch to another with the -swiftness of a common monkey, his progress being as rapid -as that of a swift horse. After receiving five balls his exertions -relaxed, and, reclining exhausted against a branch, -he vomited a quantity of blood. The ammunition of the -hunters being by this time exhausted, they were obliged to<span class="pagenum"><a id="Page_310">310</a></span> -fell the tree in order to obtain him; but what was their surprise -to see him, as the tree was falling, effect his retreat to -another, with seemingly undiminished vigour! In fact, they -were obliged to cut down all the trees before they could -force him to combat his enemies on the ground, and when -finally overpowered by numbers, and nearly in a dying state, -he seized a spear made of supple wood, which would have -withstood the strength of the stoutest man, and broke it like -a reed. It was stated, by those who aided in his death, that -the human-like expression of his countenance and his piteous -manner of placing his hands over his wounds, distressed -their feelings so as almost to make them question the nature -of the act they were committing. He was seven feet high, -with a broad expanded chest and narrow waist. His chin -was fringed with a beard that curled neatly on each side, -and formed an ornamental rather than a frightful appendage -to his visage. His arms were long even in proportion to his -height, but his legs were much shorter. Upon the whole, he -was a wonderful beast to behold, and there was more about -him to excite amazement than fear. His hair was smooth -and glossy, and his whole appearance showed him to be in -the full vigour of his youth and strength.” On the whole, -the narrative seems to suggest a remark similar to one -applied by Washington Irving to the followers of Ojeda and -their treatment of the (so-called) Indians of South America, -“we confess we feel a momentary doubt whether the arbitrary -appellation of ‘brute’ is always applied to the right party.”</p> - -<p>The other story also presents man as at least as brutal as -the orang concerned in the event. “A few miles down the -river,” says Wallace, “there is a Dyak house, and the inhabitants -saw a large orang feeding on the young shoots of a -palm by the river-side. On being alarmed he retreated -towards the jungle which was close by, and a number of the -men, armed with spears and choppers, ran out to intercept -him. The man who was in front tried to run his spear -through the animal’s body; but the orang seized it in his -hands, and in an instant got hold of the man’s arm, which<span class="pagenum"><a id="Page_311">311</a></span> -he seized in his mouth, making his teeth meet in the flesh -above the elbow, which he tore and lacerated in a dreadful -manner. Had not the others been close behind, the man -would have been more seriously injured, if not killed, as he -was quite powerless; but they soon destroyed the creature -with their spears and choppers. The man remained ill for -a long time, and never fully recovered the use of his arm.”</p> - -<p>The term gibbon includes several varieties of tail-less, -long-armed, catarhine apes. The largest variety, called the -siamang, need alone be described here.</p> - -<p>The siamang inhabits Sumatra. It presents several points -of resemblance to the orang-outang, but is also in several -respects strongly distinguished from that animal. The arms -are longer even than the orang’s, and the peculiar use which -the orang makes of his long arms is more strikingly shown -in the progression of the long-armed siamang, for the body -inclining slightly forward, when the animal is on level ground -the long arms are used somewhat like crutches, and they -advance by jerks resembling the hobbling of a lame man -whom fear compels to make an extraordinary effort. The -skull is small, and much more depressed than that of the -orang or chimpanzee. The face is naked and black, straggling -red hairs marking the eyebrows. The eyes are deeply -sunk, a peculiarity which, by the way, seems characteristic -of arboreal creatures generally;<a id="FNanchor_37" href="#Footnote_37" class="fnanchor">37</a> the nose broad and flat,<span class="pagenum"><a id="Page_312">312</a></span> -with wide-open nostrils; the cheeks sunk under high cheekbones; -the chin almost rudimentary. “The hair over the -whole body is thick, long, and of a glossy black colour, -much closer on the shoulders, back, and limbs than on the -belly, which, particularly in the females, is nearly naked. -The ears are entirely concealed by the hair of the head; -they are naked, and, like all the other naked parts, of a deep -black colour. Beneath the chin there is a large, bare sac, -of a lax and oily appearance, which is distended with air -when the animal cries, and in that state resembles an enormous -goitre. It is similar to that possessed by the orang-outang, -and undoubtedly assists in swelling the volume of the voice, -and producing those astounding cries which, according to -Duvancelle’s account, may be heard at the distance of several -miles.” This, however, may be doubted, for M. Duvancelle -himself remarks of the wouwou, that, “though deprived of -the guttural sac so remarkable in the siamang, its cry is -very nearly the same; so that it would appear that this organ -does not produce the effect of increasing the sound usually -attributed to it, or else that it must be replaced in the wouwou -by some analogous formation.”</p> - -<p>The habits of the siamang are interesting, especially in -their bearing on the relationship between the various orders -of anthropoid apes and man; for, though the gibbon is -unquestionably the lowest of the four orders of the anthropoid -apes in intelligence, it possesses some characteristics -which bring it nearer to man (so far as they are concerned) -than any of its congeners. The chief authorities respecting -the ways of the siamang are the French naturalists Diard -and Duvancelle, and the late Sir Stamford Raffles.</p> - -<p>The siamangs generally assemble in large troops, -“conducted, it is said, by a chief, whom the Malays believe -to be invulnerable, probably because he is more agile, -powerful, and difficult to capture than the rest.” “Thus -united,” proceeds M. Duvancelle (in a letter addressed to -Cuvier), “the siamangs salute the rising and the setting sun -with the most terrific cries” (like sun-worshippers), “which<span class="pagenum"><a id="Page_313">313</a></span> -may be heard at the distance of many miles, and which, -when near, stun when they do not frighten. This is the -morning call of the mountain Malays; but to the inhabitants -of the town, who are unaccustomed to it, it is an unsupportable -annoyance. By way of compensation, the siamangs -keep a profound silence during the day, unless when interrupted -in their repose or their sleep. They are slow and -heavy in their gait, wanting confidence when they climb -and agility when they leap, so that they may be easily -caught when they can be surprised. But nature, in depriving -them of the means of readily escaping danger, has -endowed them with a vigilance which rarely fails them; -and if they hear a noise which is unusual to them, even at -the distance of a mile, fright seizes them and they immediately -take flight. When surprised on the ground, however, -they may be captured without resistance, either overwhelmed -with fear or conscious of their weakness and the impossibility -of escaping. At first, indeed, they endeavour to avoid -their pursuers by flight, and it is then that their want of skill -in this exercise becomes most apparent.”</p> - -<p>“However numerous the troop may be, if one is -wounded it is immediately abandoned by the rest, unless, -indeed, it happen to be a young one. Then the mother, -who either carries it or follows close behind, stops, falls -with it, and, uttering the most frightful cries, precipitates -herself upon the common enemy with open mouth and arms -extended. But it is manifest that these animals are not -made for combat; they neither know how to deal nor to -shun a blow. Nor is their maternal affection displayed -only in moments of danger. The care which the females -bestow upon their offspring is so tender and even refined, -that one would be almost tempted to attribute the sentiment -to a rational rather than an instinctive process. It is a -curious and interesting spectacle, which a little precaution -has sometimes enabled me to witness, to see these females -carry their young to the river, wash their faces in spite of -their outcries, wipe and dry them, and altogether bestow<span class="pagenum"><a id="Page_314">314</a></span> -upon their cleanliness a time and attention that in many -cases the children of our own species might well envy. The -Malays related a fact to me, which I doubted at first, but -which I consider to be in a great measure confirmed by my -own subsequent observations. It is that the young siamangs, -whilst yet too weak to go alone, are always carried by -individuals of their own sex, by their fathers if they are -males, and by their mothers if females. I have also been -assured that these animals frequently become the prey of -the tiger, from the same species of fascination which serpents -are said to exercise over birds, squirrels, and other small -animals. Servitude, however long, seems to have no effect -in modifying the characteristic defects of this ape—his -stupidity, sluggishness, and awkwardness. It is true that a -few days suffice to make him as gentle and contented as he -was before wild and distrustful; but, constitutionally timid, -he never acquires the familiarity of other apes, and even his -submission appears to be rather the result of extreme apathy -than of any degree of confidence or affection. He is almost -equally insensible to good or bad treatment; gratitude and -revenge are equally strange to him.”</p> - -<p>We have next to consider certain points connected with -the theory of the relationship between man and the anthropoid -apes. It is hardly necessary for me to say, perhaps, -that in thus dealing with a subject requiring for its -independent investigation the life-long study of departments -of science which are outside those in which I have -taken special interest, I am not pretending to advance my -opinion as of weight in matters as yet undetermined by -zoologists. But it has always seemed to me, that when -those who have made special study of a subject collect and -publish the result of their researches, and a body of evidence -is thus made available for the general body scientific, the -facts can be advantageously considered by students of other -branches of science, so only that, in leaving for a while -their own subject, they do not depart from the true scientific -method, and that they are specially careful to distinguish<span class="pagenum"><a id="Page_315">315</a></span> -what has been really ascertained from what is only surmised -with a greater or less degree of probability.</p> - -<p>In the first place, then, I would call attention to some -very common mistakes respecting the Darwinian theory of -the Descent of Man. I do not refer here to ordinary -misconceptions respecting the theory of natural selection. -To say the truth, those who have not passed beyond <em>this</em> -stage of error,—those who still confound the theory of natural -selection with the Lamarckian and other theories (or rather -hypotheses<a id="FNanchor_38" href="#Footnote_38" class="fnanchor">38</a>) of evolution,—are not as yet in a position to -deal with our present subject, and may be left out of consideration.</p> - -<p>The errors to which I refer are in the main included in -the following statement. It is supposed by many, perhaps -by most, that according to Darwin man is descended from -one or other of the races of anthropoid apes; and that the -various orders and sub-orders of apes and monkeys at -present existing can be arranged in a series gradually -approaching more and more nearly to man, and indicating -the various steps (or some of them, for gaps exist in the -series) by which man was developed. Nothing can be -plainer, however, than Darwin’s contradiction of this -genealogy for the human races. Not only does he not for -a moment countenance the belief that the present races of -monkeys and apes can be arranged in a series gradually -approximating more and more nearly to man, not only does -he reject the belief that man is descended from any present -existing anthropoid ape, but he even denies that the progenitor -of man resembled any known ape. “We must not -fall into the error of supposing,” he says, “that the early<span class="pagenum"><a id="Page_316">316</a></span> -progenitor of the whole simian stock, including man, was -identical with, or even closely resembled, any existing ape -or monkey.”</p> - -<p>It appears to me, though it may seem somewhat bold to -express this opinion of the views of a naturalist so deservedly -eminent as Mr. Mivart, that in his interesting little treatise, -“Man and Apes,”—a treatise which may be described as -opposed to Darwin’s special views but not generally -opposed to the theory of evolution,—he misapprehends -Darwin’s position in this respect. For he arrives at the -conclusion that if the Darwinian theory is sound, then “low -down” (<i>i.e.</i>, far remote) “in the scale of Primates” (tri-syllabic) -“was an ancestral form so like man that it might -well be called an <em>homunculus</em>; and we have the virtual pre-existence -of man’s body supposed, in order to account for -the actual first appearance of that body as we know it—a -supposition manifestly absurd if put forward as an explanation.”<a id="FNanchor_39" href="#Footnote_39" class="fnanchor">39</a></p> - -<p>How, then, according to the Darwinian theory, is man -related to the monkey? The answer to this question is -simply that the relationship is the same in kind, though not -the same in degree, as that by which the most perfect -Caucasian race is related to the lowest race of Australian, -or Papuan, or Bosjesman savages. No one supposes that -one of these races of savages could by any process of evolution, -however long-continued, be developed into a race -resembling the Caucasian in bodily and mental attributes.<span class="pagenum"><a id="Page_317">317</a></span> -Nor does any one suppose that the savage progenitor of the -Caucasian races was identical with, or even closely -resembled, any existing race of savages. Yet we recognize -in the lowest forms of savage man our blood relations. In -other words, it is generally believed that if our genealogy, -and that of any existing race of savages, could be traced -back through all its reticulations, we should at length reach -a race whose blood we share with that race. It is also -generally believed (though for my own part I think the -logical consequences of the principle underlying all theories -of evolution is in reality opposed to the belief) that, by -tracing the genealogical reticulations still further back, we -should at length arrive at a single race from which all the -present races of man and no other animals have descended. -The Darwinian faith with respect to men and monkeys is -precisely analogous. It is believed that the genealogy of -every existent race of monkeys, if traced back, would lead -us to a race whose blood we share with that race of monkeys; -and—which is at once a wider and a more precise proposition—that, -as Darwin puts it, “the two main divisions of -the Simiadæ, namely, the catarhine and platyrhine monkeys, -with their sub-groups, have all proceeded from some one -extremely ancient progenitor.” This proposition is manifestly -wider. I call it also more precise, because it implies, -and is evidently intended by Darwin to signify, that from -that extremely ancient progenitor no race outside the two -great orders of Simiadæ have even partially <em>descended</em>, though -other races share with the Simiadæ descent from some still -more remote race of progenitors.</p> - -<p>This latter point, however, is not related specially to the -common errors respecting the Darwinian theory which I -have indicated above, except in so far as it is a detail of the -actual Darwinian theory. I would, in passing, point out -that, like the detail referred to in connection with the relationship -of the various races of man, this one is not logically -deducible from the theory of evolution. In fact, I have -sometimes thought that the principal difficulties of that<span class="pagenum"><a id="Page_318">318</a></span> -theory arise from this unnecessary and not logically sound -doctrine. I pointed out, rather more than three years ago, -in an article “On some of our Blood Relations,” in a weekly -scientific journal, that the analogy between the descent of -races and the descent of individual members of any race, -requires us rather to believe that the remote progenitor of -the human race and the Simiadæ has had its share—though -a less share—in the generation of other races related to these -in more or less remote degrees. I may perhaps most conveniently -present the considerations on which I based this -conclusion, by means of a somewhat familiar illustration:—</p> - -<p>Let us take two persons, brother and sister (whom let -us call the pair A), as analogues of the human race. Then -these two have four great-grandparents on the father’s side, -and four on the mother’s side. All these may be regarded -as equally related to the pair A. Now, let us suppose that -the descendants of the four families of great-grandparents -intermarry, no marriages being in any case made outside -these families, and that the descendants in the same generation -as the pair A are regarded as corresponding to the -entire order of the Simiadæ, the pair A representing, as -already agreed, the race of man, and all families outside the -descendants of the four great-grandparental families corresponding -to orders of animals more distantly related than -the Simiadæ to man. Then we have what corresponds (so -far as our illustration is concerned) to Darwin’s views respecting -man and the Simiadæ, and animals lower in the -scale of life. The first cousins of the pair A may be taken -as representing the anthropoid apes; the second cousins as -representing the lemurs or half-apes; the third cousins as -representing the platyrhine or American apes. The entire -family—including the pair A, representing man—is descended -also, in accordance with the Darwinian view, from a single -family of progenitors, no outside families sharing <em>descent</em>, -though all share <em>blood</em>, with that family.</p> - -<p>But manifestly, this is an entirely artificial and improbable -arrangement in the case of families. The eight grandparents<span class="pagenum"><a id="Page_319">319</a></span> -<em>might</em> be so removed in circumstances from surrounding -families—so much superior to them, let us say—that -neither they nor any of their descendants would intermarry -with these inferior families: and thus none of their -great-grandchildren would share descent from some other -stock contemporary with the great-grandparents; or—which -is the same thing, but seen in another light—none of the -contemporaries of the great-grandchildren would share descent -from the eight grandparents. But so complete a -separation of the family from surrounding families would be -altogether exceptional and unlikely. For, even assuming -the eight families to be originally very markedly distinguished -from all surrounding families, yet families rise and -fall, marry unequally, and within the range of a few generations -a wide disparity of blood and condition appears among -the descendants of any group of families. So that, in point -of fact, the relations assumed to subsist between man, the -Simiadæ, and lower animal forms, corresponds to an unusual -and improbable set of relations among families of several -persons. Either, then, the relations of families must be regarded -as not truly analogous to the relations of races, which -no evolutionist would assert, or else we must adopt a somewhat -different view of the relationship between man, the -Simiadæ, and inferior animals.</p> - -<p>One other illustration may serve not only to make my -argument clearer, but also, by presenting an actual case, to -enforce the conclusion to which it points.</p> - -<p>We know that the various races of man are related together -more or less closely, that some are purer than others, -and that one or two claim almost absolute purity. Now, if -we take one of these last, as, for instance, the Jewish race, -and trace the race backwards to its origin, we find it, according -to tradition, carried back to twelve families, the twelve -sons of Jacob and their respective wives. (We cannot go -further back because the wives of Jacob’s sons must be -taken into account, and they were not descended from -Abraham or Isaac and their wives only,—in fact, could not<span class="pagenum"><a id="Page_320">320</a></span> -have been.) If the descendants of those twelve families -had never intermarried with outside families in such sort -that the descendants of such mixed families came to be -regarded as true Hebrews, we should have in the Hebrews a -race corresponding to the Simiadæ as regarded by Darwin, -<i>i.e.</i>, a race entirely descended from one set of families, and -so constituting, in fact, a single family. But we know that, -despite the objections entertained by the Hebrews against -the intermixture of their race with other races, this did not -happen. Not only did many of those regarded as true -Hebrews share descent from nations outside their own, but -many of those regarded as truly belonging to nations outside -the Jewish race shared descent from the twelve sons of -Jacob.</p> - -<p>The case corresponding, then, to that of the purest of all -human races, and the case therefore most favourable to the -view presented by Darwin (though very far from essential to -the Darwinian theory), is simply this, that, in the first place, -many animals regarded as truly Simiadæ share descent from -animals outside that family which Darwin regards as the ape -progenitor of man; and, in the second place, many animals -regarded as outside the Simiadæ share descent from that -ape-like progenitor. This involves the important inference -that the ape-like progenitor of man was not so markedly -differentiated from other families of animals then existing, -that fertile intercourse was impossible. A little consideration -will show that this inference accords well with, if it might -not almost have been directly deduced from, the Darwinian -doctrine that all orders of mammals were, in turn, descended -from a still more remote progenitor race. The same considerations -may manifestly be applied also to that more -remote race, to the still more remote race from which all the -vertebrates have descended, and so on to the source itself -from which all forms of living creatures are supposed to -have descended. A difficulty meets us at that remotest end -of the chain analogous to the difficulty of understanding how -life began at all; but we should profit little by extending<span class="pagenum"><a id="Page_321">321</a></span> -the inquiry to these difficulties, which remain, and are likely -long to remain, insuperable.</p> - -<p>So far, however, are the considerations above urged from -introducing any new or insuperable objection to the Darwinian -theory, that, rightly understood, they indicate the -true answer to an objection which has been urged by Mivart -and others against the belief that man has descended from -some ape-like progenitor.</p> - -<p>Mivart shows that no existing ape or monkey approaches -man more nearly in all respects than other races, but that -one resembles man more closely in some respects, another -in others, a third in yet others, and so forth. “The ear -lobule of the gorilla makes him our cousin,” he says, “but -his tongue is eloquent in his own dispraise.” If the “bridging -convolutions of the orang[’s brain] go to sustain his -claim to supremacy, they also go far to sustain a similar -claim on the part of the long-tailed thumbless spider-monkeys. -If the obliquely ridged teeth of <i>Simia</i> and <i>Troglodytes</i> -(the chimpanzee) point to community of origin, how -can we deny a similar community of origin, as thus estimated, -to the howling monkeys and galagos? The liver of -the gibbons proclaims them almost human; that of the -gorilla declares him comparatively brutal. The lower -American apes meet us with what seems the ‘front of Jove -himself,’ compared with the gigantic but low-browed denizens -of tropical Western Africa.”</p> - -<p>He concludes that the existence of these wide-spread -signs of affinity and the associated signs of divergence, disprove -the theory that the structural characters existing in -the human frame have had their origin in the influence of -inheritance and “natural selection.” “In the words of the -illustrious Dutch naturalists, Messrs. Schroeder, Van der -Kolk and Vrolik,” he says, “the lines of affinity existing -between different Primates construct rather a network than -a ladder. It is indeed a tangled web, the meshes of which -no naturalist has as yet unravelled by the aid of natural -selection. Nay, more, these complex affinities form such a<span class="pagenum"><a id="Page_322">322</a></span> -net for the use of the teleological <i xml:lang="la" lang="la">retiarius</i> as it will be -difficult for his Lucretian antagonist to evade, even with the -countless turns and doublings of Darwinian evolutions.”</p> - -<p>It appears to me that when we observe the analogy between -the relationships of individuals, families, and races of -man, and the relationships of the various species of animals, -the difficulty indicated by Mr. Mivart disappears. Take, for -instance, the case of the eight allied families above considered. -Suppose, instead of the continual intermarriages -before imagined—an exceptional order of events, be it remembered—that -the more usual order of things prevails, -viz., that alliances take place with other families. For simplicity, -however, imagine that each married pair has two -children, male and female, and that each person marries -once and only once. Then it will be found that the pair A -have ten families of cousins, two first-cousin families, and -eight second-cousin families; these are all the families which -share descent from the eight great-grandparents of the pair. -(To have third-cousin families we should have to go back to -the fourth generation.) Thus there are eleven families in -all. Now, in the case first imagined of constant intermarrying, -there would still have been eleven families, but they -would all have descended from eight great-grandparents, -and we should then expect to find among the eleven families -various combinations, so to speak, of the special characteristics -of the eight families from which they had descended. -On the other hand, eleven families, in <em>no</em> way connected, -have descended from eighty-eight great-grandparents, and -would present a corresponding variety of characteristics. -But in the case actually supposed, in which the eleven -families are so related that each one (for what applies to the -pair A applies to the others) has two first-cousin families, -and eight second-cousin families, it will be found that instead -of 88 they have only 56 great-grandparents, or ancestors, in -the third generation above them. The two families related -as first cousins to the pair A have, like these, eight great-grandparents, -four out of these eight for one family, being<span class="pagenum"><a id="Page_323">323</a></span> -the four grandparents of the father of the pair A, the other -four being outsiders; while four of the eight great-grandparents -of the other family of first cousins are the four -grandparents of the mother of the pair A, the other four -being outsiders. The other eight families each have eight -great-grandparents; two of the families having among their -great-grandparents the parents of one of the grandfathers of -the pair A, but no other great-grandparent in common with -the pair A; other two of the eight families having among -their great-grandparents the parents of the other grandfather -of the pair A; other two having among their great-grandparents -the parents of one of the grandmothers of the -pair A; the remaining two families having among their -great-grandparents the parents of the other grandmother of -the pair A; while in all cases the six remaining great-grandparents -of each family are outsiders, in no way related, on -our assumption, either to the eight great-grandparents of the -pair A or to each other, except as connected in pairs by -marriage.</p> - -<p>Now manifestly in such a case, which, save for the -symmetry introduced to simplify its details, represents fairly -the usual relationships between any family, its first cousins, -and its second cousins, we should not expect to find any one -of the ten other families resembling the pair A more closely -in <em>all</em> respects than would any other of the ten. The two -first-cousin families would <em>on the whole</em> resemble the pair A -more nearly than would any of the other eight, but we should -expect to find <em>some</em> features or circumstances in which one or -other or all of the second-cousin families would show a -closer resemblance to one or other or both of the pair A. -This is found often, perhaps generally, to be the case, even -as respects the ordinary characteristics in which resemblance -is looked for, as complexion, height, features, manner, disposition, -and so forth. Much more would it be recognized, -if such close investigation could be made among the various -families as the naturalist can make into the characteristics of -men and animals. The fact, then, that features of resemblance<span class="pagenum"><a id="Page_324">324</a></span> -to man are found, not all in one order of the -Simiadæ, but scattered among the various orders, is perfectly -analogous with the laws of resemblance recognized among -the various members of more or less closely related families.</p> - -<p>The same result follows if we consider the analogy between -various different species of animals on the one hand -and between various races of the human family on the other. -No one thinks of urging against the ordinary theory that -men form only a single species, the objection that none of -the other families of the human race can be regarded as the -progenitor of the Caucasian family, seeing that though the -Mongolian type is nearer in some respects, the Ethiopian is -nearer in others, the American in others, the Malay in yet -others. We find in this the perfect analogue of what is recognized -in the relationships between families all belonging to -one nation, or even to one small branch of a nation. Is it -not reasonable, then, to find in the corresponding features -of scattered resemblance observed among the various -branches of the great Simian family, not the objection which -Mivart finds against the theory of relationship, but rather -what should be expected if that theory is sound, and therefore, -<i xml:lang="la" lang="la">pro tanto</i>, a confirmation of the theory?</p> - -<p>But now, in conclusion, let us briefly consider the great -difficulty of the theory that man is descended from some -ape-like, arboreal, speechless animal,—the difficulty of bridging -over the wide gap which confessedly separates the lowest -race of savages from the highest existing race of apes. After -all that has been done to diminish the difficulty, it remains -a very great one. It is quite true that what is going on at -this present time shows how the gap has been widened, and -therefore indicates how it may once have been comparatively -small. The more savage races of man are gradually disappearing -on the one hand, the most man-like apes are being -destroyed on the other,—so that on both sides of the great -gap a widening process is at work. Ten thousand years -hence the least civilized human race will probably be little -inferior to the average Caucasian races of the present day,<span class="pagenum"><a id="Page_325">325</a></span> -the most civilized being far in advance of the most advanced -European races of our time. On the other hand, the gorilla, -the chimpanzee, the orang-outang, and the gibbon will probably -be extinct or nearly so. True, the men of those days -will probably have very exact records of the characteristics -not only of the present savage races of man, but of the present -races of apes. Nay, they will probably know of intermediate -races, long since extinct even now, whose fossil -remains geologists hope to discover before long as they have -already discovered the remains of an ape as large as man -(the <i>Dryopithecus</i>) which existed in Europe during the -Miocene period;<a id="FNanchor_40" href="#Footnote_40" class="fnanchor">40</a> and more recently the remains of a race -of monkeys akin to Macacus, which once inhabited Attica. -But although our remote descendants will thus possess -means which we do not possess of bridging the gap between -the highest races of apes and the lowest races of man, the -gap will nevertheless be wider in their time. And tracing -backwards the process, which, thus traced forward, shows a -widened gap, we see that once the gap must have been much -narrower than it is. Lower races of man than any now -known once existed on the earth, and also races of apes -nearer akin to man than any now existing, even if the present -races of apes are not the degraded descendants of races -which, living under more favourable conditions, were better -developed after their kind than the gorilla, chimpanzee, -orang, and gibbon of the present time.</p> - -<p>It may be, indeed, that in the consideration last suggested -we may find some assistance in dealing with our difficult -problem. It is commonly assumed that the man-like -apes are the most advanced members of the Simian family -save man alone, and so far as their present condition is concerned -this may be true. But it is not necessarily the case<span class="pagenum"><a id="Page_326">326</a></span> -that the anthropoid apes have advanced to their present -condition. Judging from the appearance of the young of -these races, we may infer with some degree of probability -that these apes are the degraded representatives of more intelligent -and less savage creatures. Whereas the young of -man is decidedly more savage in character than the well-nurtured -and carefully trained adult, the young of apes are decidedly -less savage than the adult. The same reasoning which -leads us to regard the wildness, the natural cruelty, the destructiveness, -the love of noise, and many other little ways -of young children, as reminders of a more or less remote -savage ancestry, should lead us to regard the comparative -tameness and quiet of the young gorilla, for example, as -evidence that in remote times the progenitors of the race -were not so wild and fierce as the present race of gorillas.</p> - -<p>But even when all such considerations, whether based on -the known or the possible, have been taken into account, -the gap between the lowest savage and the highest ape is not -easily bridged. It is easier to see how man <em>may</em> have -developed from an arboreal, unspeaking animal to his present -state, than to ascertain how any part of the development -was actually effected; in other words, it is easier to suggest -a general hypothesis than to establish an even partial -theory.</p> - -<p>That the progenitor of man was arboreal in his habits -seems altogether probable. Darwin recognizes in the -arrangement of the hair on the human forearm the strongest -evidence on this point, so far as the actual body of man is -concerned; the remaining and perhaps stronger evidence -being derived from appearances recognized in the unborn -child. He, who usually seems as though he could overlook -nothing, seems to me to have overlooked a peculiarity which -is even more strikingly suggestive of original arboreal habits. -There is one set of muscles, and, so far as I know, one -only, which the infant uses freely, while the adult scarcely -uses them at all. I mean the muscles which separate the -toes, and those, especially, which work the big toe. Very<span class="pagenum"><a id="Page_327">327</a></span> -young children not only move the toes apart, so that the -great toe and the little toe will be inclined to each other (in -the plane of the sole) nearly ninety degrees, but also distinctly -clutch with the toes. The habit has no relation to -the child’s actual means of satisfying its wants. I have -often thought that the child’s manner of clutching with its -fingers is indicative of the former arboreal habits of the -race, but it is not difficult to explain the action otherwise. -The clutching movement of the toes, however, cannot be so -explained. The child can neither bring food to its mouth -in this way nor save itself from falling; and as the adult -does not use the toes in this way the habit cannot be regarded -as the first imperfect effort towards movements subsequently -useful. In fact, the very circumstance that the -movement is gradually disused shows that it is useless to the -human child in the present condition of the race. In the -very young gorilla the clutching motion of the toes is -scarcely more marked than it is in a very young child; only -in the gorilla the movement, being of use, is continued by -the young, and is developed into that effective clutch with -the feet which has been already described. Here we have -another illustration of that divergency which, rather than -either simple descent or ascent, characterizes the relationship -between man and the anthropoid ape. In the growing -gorilla a habit is more and more freely used, which is more -and more completely given up by the child as he progresses -towards maturity.</p> - -<p>Probably the arboreal progenitor of man was originally -compelled to abandon his arboreal habits by some slow -change in the flora of his habitat, resulting in the diminution -and eventual disappearance of trees suited for his movements. -He would thus be compelled to adopt, at first, -some such course as the chimpanzee—making huts of such -branches and foliage as he could conveniently use for the -purpose. The habit of living in large companies would (as -in the case of the chimpanzee) become before long necessary, -especially if the race or races thus driven from their former<span class="pagenum"><a id="Page_328">328</a></span> -abode in the trees were, like the gibbons, unapt when alone -both in attack and in defence. One can imagine how the -use of vocal signals of various kinds would be of service to -the members of these troops, not only in their excursions, -but during the work of erecting huts or defences against -their enemies. If in two generations the silent wild dog -acquires, when brought into the company of domestic dogs, -no less than five distinct barking signals, we can well believe -that a race much superior in intelligence, and forced by -necessity to associate in large bodies, would—in many -hundreds of generations, perhaps—acquire a great number -of vocal symbols. These at first would express various -emotions, as of affection, fear, anxiety, sympathy, and so -forth. Other signals would be used to indicate the approach -of enemies, or as battle-cries. I can see no reason why -gradually the use of particular vocal signs to indicate various -objects, animate or inanimate, and various actions, should -not follow after a while. And though the possession and -use of many, even of many hundreds, of such signs would be -very far from even the most imperfect of the languages now -employed by savage races, one can perceive the possibility—which -is all that at present we can expect to recognize—that -out of such systems of vocal signalling a form of language -might arise, which, undergoing slow and gradual development, -should, in the course of many generations, approach -in character the language of the lowest savage races. That -from such a beginning language should attain its higher and -highest developments is not more wonderful in kind, though -much more wonderful, perhaps, in degree, than that from -the first imperfect methods of printing should have arisen -the highest known developments of the typographic art. -The real difficulty lies in conceiving how mere vocal signalling -became developed into what can properly be regarded -as spoken language.</p> - -<p>Of the difficulties related to the origin of, or rather the -development of, man’s moral consciousness, space will not -permit me to speak, even though there were much to be said<span class="pagenum"><a id="Page_329">329</a></span> -beyond the admission that these difficulties have not as yet -been overcome. It must be remembered, however, that -races of men still exist whose moral consciousness can hardly -be regarded as very fully developed. Not only so, but, -through a form of reversion to savage types, the highest -and most cultivated races of man bring forth from time to -time (as our police reports too plainly testify) beings utterly -savage, brutal, and even (“which is else”) bestial. Nay, the -man is fortunate who has never had occasion to control innate -tendencies to evil which are at least strongly significant of -the origin of our race. To most minds it must be pleasanter -as certainly it seems more reasonable, to believe that the -evil tendencies of our race are manifestations of qualities -undergoing gradual extinction, than to regard them as the -consequences of one past offence, and so to have no reason -for trusting in their gradual eradication hereafter. But, as -Darwin says, in the true scientific spirit, “We are not here -concerned with hopes or fears, only with the truth as far as -our reason allows us to discover it. We must acknowledge -that man, with all his noble qualities, with sympathy which -feels for the most debased, with benevolence which extends -not only to other men but to the humblest living creature, -with his God-like intellect which has penetrated into the -movements and constitution of the solar system,—with all -these exalted powers, man still bears in his bodily frame the -indelible stamp of his lowly origin.” As it seems to me, -man’s moral nature teaches the same lesson with equal, if -not greater, significance.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_330">330</a></span></p> - -<div class="chapter"> -<h2><a id="THE_USE_AND_ABUSE_OF_FOOD"></a><i>THE USE AND ABUSE OF FOOD.</i></h2> -</div> - -<p class="in0">Francis Bacon has laid it down as an axiom that experiment -is the foundation of all real progress in knowledge. “Man,” -he said, “as the minister and interpreter of nature, does and -understands as much as his observations on the order of -nature permit him, and neither knows nor is capable of -more.”<a id="FNanchor_41" href="#Footnote_41" class="fnanchor">41</a> It would seem, then, as if there could be no -subject on which man should be better informed than on the -value of various articles of food, and the quantity in which -each should be used. On most branches of experimental -inquiry, a few men in each age—perhaps but for a few ages -in succession—have pursued for a longer or shorter portion -of their life, a system of experiment and observation. But -on the subject of food or diet all men in all ages have been -practical experimenters, and not for a few years only, but -during their entire life. One would expect, then, that no -questions could be more decisively settled than those which -relate to the use or the abuse of food. Every one ought to -know, it might be supposed, what kinds of food are good for -the health, in what quantity each should be taken, what -changes of diet tend to correct this or that kind of ill-health, -and how long each change should be continued.</p> - -<p>Unfortunately, as we know, this is far from being the -case. We all eat many things which are bad for us, and -omit to eat many things which would be good for us. We<span class="pagenum"><a id="Page_331">331</a></span> -change our diet, too often, without any consideration, or -from false considerations, of the wants of the body. When -we have derived benefit from some change of diet, we are -apt to continue the new diet after the necessity for it has -passed away. As to quantity, also, we seldom follow well-judged -rules. Some take less nutriment (or less of some -particular form of nutriment) than is needed to supply the -absolute requirements of the system; others persistently -overload the system, despite all the warnings which their -own experience and that of others should afford of the mischief -likely to follow that course.</p> - -<p>It is only of late years that systematic efforts have been -made to throw light on the subject of the proper use of food, -to distinguish between its various forms, and to analyze the -special office of each form. I propose to exhibit, in a -popular manner, some of the more important practical conclusions -to which men of science have been led by their -investigations into these questions.</p> - -<p>The human body has been compared to a lamp in which -a flame is burning. In some respects the comparison is a -most apt one, as we shall see presently. But man does -more than <em>live</em>; he <em>works</em>,—with his brain or with his -muscles. And therefore the human frame may be more -justly compared to a steam-engine than to the flame of a -lamp. Of mere life, the latter illustration is sufficiently apt, -but it leaves unillustrated man’s capacity for work; and -since food is taken with two principal objects—the maintenance -of life and the renewal of material used up in brain -work and muscular work—we shall find that the comparison -of man to a machine affords a far better illustration of our -subject than the more common comparisons of the life of man -to a burning flame, and of food to the fuel which serves to -maintain combustion.</p> - -<p>There is, however, one class of food, and, perhaps, on -the whole, the most important, the operation of which is -equally well illustrated by either comparison. The sort of -food to which I refer may be termed <em>heat-maintaining</em> food.<span class="pagenum"><a id="Page_332">332</a></span> -I distinguish it thus from food which serves other ends, but -of course it is not to be understood that any article of diet -serves <em>solely</em> the end of maintaining heat. Accordingly, we -find that heat-maintaining substance exists in nearly all the -ordinary articles of food. Of these there are two—sugar -and fat—which may be looked on as special “heat-givers.” -Starch, also, which appears in all vegetables, and thus comes -to form a large proportion of our daily food, is a heat-giver. -In fact, this substance only enters the system in the form of -sugar, the saliva having the power of converting starch -(which is insoluble in water) into sugar, and thus rendering -it soluble and digestible.</p> - -<p>Starch, as I have said, appears in all vegetables. But it -is found more freely in some than in others. It constitutes -nearly the whole substance of arrowroot, sago, and tapioca, -and appears more or less freely in potatoes, rice, wheat, -barley, and oats. In the process of vegetation it is converted -into sugar; and thus it happens that vegetable diet—whether -presenting starch in its natural form to be converted into -sugar by the consumer, or containing sugar which has -resulted from a process of change undergone by starch—is -in general heat-maintaining. Sugar is used as a convenient -means of maintaining the heat-supply; for in eating sugar -we are saved the trouble of converting starch into sugar. A -love for sweet things is the instinctive expression of the -necessity for heat-maintaining food. We see this liking -strongly developed in children, whose rapid growth is continually -drawing upon their heat-supply. So far as adults -are concerned, the taste for sweet food is found to prevail -more in temperate than in tropical climes, as might be -expected; but, contrary to what we might at first expect, -we do not find any increase in the liking for sweet food in -very cold climates. Another and a more effective way of -securing the required heat-supply prevails in such countries.</p> - -<p>As starch is converted into sugar, so by a further process -sugar is converted into fat. It is by the conversion of sugar -into fat that its heat-supplying power is made available.<span class="pagenum"><a id="Page_333">333</a></span> -This conversion takes place in the vegetable as well as in -the animal system, and thus fat appears in a variety of forms—as -butter, suet, oil, and so forth. Now, precisely as sugar -is a more convenient heat-supplier than starch, so fat -exceeds sugar in its power of maintaining animal heat. It -has been calculated that one pound of fat—whether in the -form of suet, butter, or oil—will go as far towards the -maintenance of animal heat as two pounds of sugar, or as -two pounds and a half of starch. Thus it happens that in -very cold countries there is developed a taste for such -articles of food as contain most fat, or even for pure fat and -its analogues—oil, butter, tallow, dripping, and other forms -of <em>grease</em>.</p> - -<p>I have spoken of starch, sugar, and fat as heat-forming -articles of food; but I must note their influence in the -development of muscles and nerves. Without a certain -proportion of fat in the food a wasting of the tissues will -always take place; for muscles and nerves cannot form -without fat. And conversely, the best remedy for wasting -diseases is to be found in the supply of some easily digestible -form of fatty food. Well-fatted meat, and especially meat in -which the fat is to be seen distributed through the flesh, may -be taken under such circumstances. Butter and salad oil -are then also proper articles of food. Cream is still better, -and cream cheeses may be used with advantage. It is on -account of its heat-supplying and fat-forming qualities that -cod-liver oil has taken its place as one of the most valuable -remedies for scrofulous and consumptive patients.</p> - -<p>But it must be noted that the formation of fat is not the -object with which heat-supplying food is taken. It is an -indication of derangement of the system when heat-giving -food is too readily converted into fat. And in so far as this -process of conversion takes place beyond what is required -for the formation of muscles and nerves, the body suffers in -the loss of its just proportion of heat-supply. Of course, if -too large an amount of heat-giving food is taken into the -system, we may expect that the surplus will be deposited in<span class="pagenum"><a id="Page_334">334</a></span> -the form of adipose tissue. The deposition of fat in such a -case will be far less injurious to the system than an excessive -heat-supply would be. But when only a just amount of -heat-giving food is taken, and in place of fulfilling its just -office this food is converted into adipose tissue, it becomes -necessary to inquire into the cause of the mischief. -Technically, the evil may be described as resulting from the -deficient oxygenation of the heat-supplying food. This -generally arises from defective circulation, and may often be -cured by a very moderate but <em>systematic</em> increase in the -amount of daily exercise, or by the use of the sponge-bath, -or, lastly, by such changes in the dress—and especially in -the articles of attire worn next to the skin—as tend to -encourage a freer circulation of the blood. The tendency -to accumulate fat may sometimes be traced to the use of -over-warm coverings at night, and especially to the use of -woollen night-clothes. By attending to considerations of -this sort, more readily and safely than by an undue diminution -of the amount of heat-supplying food, the tendency to -obesity may frequently be corrected.</p> - -<p>In warm weather we should diminish the supply of heat-giving -food. In such weather the system does not require -the same daily addition to its animal heat, and the excess is -converted into fat. Experiments have shown that despite the -increased rate at which perspiration proceeds during the -summer months, men uniformly fed throughout the year increase -in weight in summer and lose weight in winter.</p> - -<p>So far as mere existence is concerned, heat-forming food -may be looked upon as the real fuel on which the lamp of -life is sustained. But man, considered as a working being, -cannot exist without <em>energy-forming</em> food. All work, whether -of the brain or of the limbs, involves the exhaustion of -nervous and muscular matter; and unless the exhausted -matter be renewed, the work must come to an end. The -supply of heat-giving food may be compared to the supply -of fuel for the fire of a steam-engine. By means of this -supply the <em>fire</em> is kept alive; but if the fire have nothing to<span class="pagenum"><a id="Page_335">335</a></span> -work upon, its energies are wasted or used to the injury of -the machine itself. The supply of water, and its continual -use (in the form of steam) in the propulsion of the engine, -are the processes corresponding to the continual exhaustion -and renewal of the muscles and nerves of the human frame. -And the comparison may be carried yet further. We see -that in the case of the engine the amount of smoke, or -rather of carbonic acid, thrown out by the blast-pipe is a -measure of the vital energy (so to speak) within the engine; -but the amount of work done by the engine is measured -rather by the quantity of steam which is thrown out, because -the elastic force of every particle of steam has been exerted -in the propulsion of the engine before being thrown out -through the blast-pipe. In a manner precisely corresponding -to this, the amount of carbonic acid gas exhaled by a -man is a measure of the rate at which mere existence is proceeding; -but the amount of work, mental or muscular, -which the man achieves, is measured by the amount of used-up -brain-material and muscle-material which is daily thrown -off by the body. I shall presently show in what way this -amount is estimated.</p> - -<p>In the composition of the muscles there is a material -called <em>fibrine</em>, and in the composition of the nerves there is -a material called <em>albumen</em>. These are the substances<a id="FNanchor_42" href="#Footnote_42" class="fnanchor">42</a> which -are exhausted during mental and bodily labour, and which -have to be renewed if we are to continue working with our -head or with our hands. Nay more, life itself involves -work; the heart, the lungs, the liver, each internal organ of -the body, performs its share of work, just as a certain proportion -of the power of a steam-engine is expended in merely -moving the machinery which sets it in action. If the waste -of material involved in this form of work is not compensated<span class="pagenum"><a id="Page_336">336</a></span> -by a continual and sufficient supply of fibrine and albumen -the result will be a gradual lowering of all the powers of the -system, until some one or other gives way,—the heart ceases -to beat, or the stomach to digest, or the liver to secrete bile,—and -so death ensues.</p> - -<p>The fibrine and albumen in the animal frame are derived -exclusively from vegetables. For although we seem to -derive a portion of the supply from animal food, yet the -fibrine and albumen thus supplied have been derived in the -beginning from the vegetable kingdom. “It is the peculiar -property of the plant,” says Dr. Lankester, “to be able, in -the minute cells of which it is composed, to convert the carbonic -acid and ammonia which it gets from the atmosphere -into fibrine and albumen, and by easy chemical processes -we can separate these substances from our vegetable food. -Wheat, barley, oats, rye, rice, all contain fibrine, and some -of them also albumen. Potatoes, cabbage, and asparagus -contain albumen. It is a well-ascertained fact that those -substances which contain most of these ‘nutritious secretions,’ -as they have been called, support life the longest.” -They change little during the process of digestion, entering -the blood in a pure state, and being directly employed to -renew the nervous and muscular matter which has been -used up during work, either mental or muscular. Thus the -supply of these substances is continually being drawn upon. -The carbon, which forms their principal constituent, is converted -into carbonic acid; and the nitrogen, which forms -about a sixth part of their substance, re-appears in the nitrogen -of urea, a substance which forms the principal solid -constituent of the matter daily thrown from the system -through the action of the kidneys. Thus the amount of -urea which daily passes from the body affords a measure of -the work done during the day. “This is not,” says Dr. -Lankester, “the mere dream of the theorist; it has been -practically demonstrated that increased stress upon the -nervous system, viz., brain work, emotion, or excitement -from disease, increases the quantity of urea and the demand<span class="pagenum"><a id="Page_337">337</a></span> -for nitrogenous food. In the same manner the amount of -urea is the representative of the amount of muscular work -done.”</p> - -<p>It has been calculated that the average amount of urea -daily formed in the body of a healthy man is about 470 -grains. To supply this daily consumption of nitrogenous -matter, it is necessary that about four ounces of flesh-forming -substance should be consumed daily. It is important, -therefore, to inquire how this substance may be obtained. -The requisite quantity of albuminous and fibrinous matter -“is contained,” says Dr. Lankester, “in a pound of beef; in -two pounds of eggs; in two quarts of milk; in a pound of -peas; in five pounds of rice; in sixteen pounds of potatoes; -in two pounds of Indian meal; in a pound and a half of -oatmeal; and in a pound and three-quarters of flour.” A -consideration of this list will show the importance of attending -to the quality as well as the quantity of our food. A -man of ordinary appetite might satisfy his hunger on potatoes -or on rice, without by any means supplying his system with -a sufficient amount of flesh-forming food. On the other -hand, if a man were to live on bread and beef alone, he -would load his system with an amount of nitrogenous food, -although not taking what could be considered an excessive -amount of daily nourishment. We see, also, how it is -possible to continually vary the form in which we take the -required supply of nitrogenous food, without varying the -amount of that supply from day to day.</p> - -<p>The supply itself should of course also vary from day to -day as the amount of daily work may vary. What would be -ample for a person performing a moderate amount of work -would be insufficient for one who underwent daily great -bodily or mental exertions, and would be too much for one -who was taking holiday. It would appear, from the researches -of Dr. Haughton, that the amount of urea daily -formed in the body of a healthy man of average weight varies -from 400 to 630 grains. Of this weight it appears that 300 -grains results from the action of the internal organs. It<span class="pagenum"><a id="Page_338">338</a></span> -would seem, therefore, that the amount of flesh-forming food -indicated in the preceding paragraph may be diminished in -the proportion of 47 to 40 in the case of a person taking the -minimum of exercise—that is, avoiding all movements save -those absolutely necessary for comfort or convenience. On -the other hand, that amount must be increased in the proportion -of 74 to 63 in the case of a person (of average weight) -working up to his full powers. It will be seen at once, -therefore, that a hardworking man, whether labourer or -thinker, must make good flesh-forming food constitute a considerable -portion of his diet; otherwise he would require to -take an amount of food which would seriously interfere with -his comfort and the due action of his digestive organs. For -instance, if he lived on rice alone, he would require to ingest -nearly seven pounds of food daily; if on potatoes, he would -require upwards of twenty-one pounds; whereas one pound -and a third of meat would suffice to supply the same amount -of flesh-forming food.</p> - -<p>Men who have to work, quickly find out what they -require in the way of food. The Irishman who, while doing -little work, will live contentedly on potatoes, asks for better -flesh-forming food when engaged in heavy labour. In fact, -the employer of the working man, so far from feeling aggrieved -when his men require an improvement in their diet, -either as respects quality or quantity, ought to look on the -want as evidence that they are really working hard in his -service, and also that they have a capacity for continuous -work. The man who lives on less than the average share of -flesh-forming food is doing less than an average amount of -work; the man who is unable to eat an average quantity -of flesh-forming food, is <em>unable</em> to do an average amount of -work. “‘On what principle do you discharge your men?’ -I once said,” relates Dr. Lankester, “to a railway contractor. -‘Oh,’ he said, ‘it’s according to their appetites.’ ‘But,’ I -said, ‘how do you judge of that?’ ‘Why,’ he said, ‘I send a -clerk round when they are getting their dinners, and those -who can’t eat he marks with a bit of chalk, and we send -them about their business.’”</p> - -<p><span class="pagenum"><a id="Page_339">339</a></span> -At a lecture delivered at the Royal Museum of Physics -and Natural History at Florence, by Professor Mantegazza, -a few years since, the Professor dwelt on the insufficient food -which Italians are in the habit of taking, as among the most -important causes of the weakness of the nation. “Italians,” -he said, “you should follow as closely as you can the -example of the English in your eating and in your drinking, -in the choice of flesh-meat (in tossing off bumpers of your -rich wines),<a id="FNanchor_43" href="#Footnote_43" class="fnanchor">43</a> in the quality of your coffee, your tea, and your -tobacco. I give you this advice, dear countrymen, not only -as a medical man, but also as a patriot. It is quite evident, -from the way millions of you perform the process which you -call eating and drinking, that you have not the most elementary -notions of the laws of physiology. You imagine -that you are living. You are barely prolonging existence on -maccaroni and water-melons. You neither know how to eat -nor how to drink. You have no muscular energy; and, -therefore, you have no continuous mental energy. The -weakness of the individual, multiplied many millions of times, -results in the collective weakness of the nation. Hence results -insufficient work, and thence insufficient production. Thus -the returns of the tax-collector and the custom-house officer -are scanty, and the national exchequer suffers accordingly.” -Nor is all this, strange as it may sound, the mere gossip of -the lecture-room. “The question of good feeding,” says -Dr. Lankester, “is one of national importance. It is vain -to expect either brain or muscles to do efficient work when -they are not provided with the proper material. Neither -intellectual nor physical work can be done without good -food.”</p> - -<p>We have now considered the two principal forms of -food, the heat-forming—sometimes called the <em>amylaceous</em>—constituents, -and the flesh-forming or <em>nitrogenous</em> constituents. -But there are other substances which, although forming a -smaller proportion of the daily food, are yet scarcely less<span class="pagenum"><a id="Page_340">340</a></span> -important. Returning to our comparison of the human -system to a steam-engine—we have seen how the heat-forming -and flesh-forming constituents of food correspond to the -supply of fuel and water; but an engine would quickly fall -into a useless state if the wear and tear of the material of -which it is constructed were not attended to and repaired. -Now, in the human frame there are materials which are continually -being used up, and which require to be continually -restored, if the system is to continue free from disease. -These materials are the mineral constituents of the system. -Amongst them we must include <em>water</em>, which composes a -much larger portion of our bodies than might be supposed. -Seven-ninths of our weight consists simply of water. Every -day there is a loss of about one-thirtieth part of this constituent -of our system. The daily repair of this important -waste of material is not effected by imbibing a corresponding -supply of water. A large proportion of the weight of water -daily lost is renewed in the solid food. Many vegetables -consist principally of water. This is notably the case with -potatoes. Where the water supplied to a district is bad, so -that little water is consumed by the inhabitants—at least, -without the addition of some other substance—it becomes -important to notice the varying proportion of water present -in different articles of food. As an instance of this, I may -call attention to a remarkable circumstance observed during -the failure of the potato crops in Ireland. Notwithstanding -the great losses which the people sustained at that time, it -was noticed that the amount of tea imported into Ireland -exhibited a remarkable increase. This seemed at first sight -a somewhat perplexing phenomenon. The explanation was -recognized in the circumstance that the potato—a watery -vegetable, as we have said—no longer formed the chief -portion of the people’s diet. Thus the deficiency in the -supply of water had to be made up by the use of a larger -quantity of fluid food; and as simple water was not palatable -to the people, they drank tea in much larger quantities than -they had been in the habit of taking before the famine.</p> - -<p><span class="pagenum"><a id="Page_341">341</a></span> -But we have to consider the other mineral constituents of -the system.</p> - -<p>If I were to run through the list of all the minerals which -exist within the body, I should weary the patience of the -reader, and perhaps not add very much to the clearness of -his ideas respecting the constitution of the human frame. -Let it suffice to state generally that, according to the calculations -of physiologists, a human body weighing 154 pounds -contains about 17½ pounds of mineral matter; and that the -most important mineral compounds existing within the body -are those which contain lime, soda, and potash. Without -pretending to any strictly scientific accuracy in the classification, -we may say that the lime is principally found in the -bones, the soda in the blood, the potash in the muscles; and -according as one or other of these important constituents is -wanting in our food, so will the corresponding portions of the -frame be found to suffer.</p> - -<p>We have a familiar illustration of the effects of unduly -diminishing the supply of the mineral constituents of the -body in the ravages which scurvy has worked amongst the -crews of ships which have remained for a long period ill-supplied -with fresh vegetables. Here it is chiefly the want -of potash in the food which causes the mischief. An interesting -instance of the rapid—almost startling—effects of food -containing potash, in the cure of men stricken by scurvy, -is related by Dana. The crew of a ship which had been -several months at sea, but was now nearing the land, were -prostrated by the ravages of scurvy. Nearly all seemed hopelessly -ill. One young lad was apparently dying, the livid -spots which were spreading over his limbs seeming to betoken -his rapidly approaching end. At this moment a ship appeared -in view which had but lately left the land, and was -laden with fresh vegetables. Before long large quantities of -the life-bearing food had been transferred to the decks of the -other ship. The instincts of life taught the poor scurvy-stricken -wretches to choose the vegetable which of all others -was best suited to supply the want under which their frames<span class="pagenum"><a id="Page_342">342</a></span> -were wasting. They also were led by the same truthful -instincts to prefer the raw to cooked vegetables. Thus the -sick were to be seen eating raw onions with a greater relish -than the gourmand shows for the most appetising viands. -But the poor lad who was the worse of the sufferers had -already lost the power of eating; and it was without a hope -of saving his life that some of his companions squeezed the -juice of onions between his lips, already quivering with the -tremor of approaching death. He swallowed a few drops, -and presently asked for more. Shortly he began to revive, -and to the amazement of all those who had seen the state of -prostration to which he had been reduced, he regained in a -few days his usual health and strength.</p> - -<p>The elements which we require in order to supply the -daily waste of the mineral constituents of the body are contained -in greater or less quantities in nearly all the articles -which man uses for food. But it may readily happen that, -by adopting an ill-regulated diet, a man may not take a -sufficient quantity of these important elements. It must -also be noticed that articles of food, both animal and -vegetable, may be deprived of a large proportion of their -mineral elements by boiling; and if, as often happens, the -water in which the food has been boiled is thrown away, -injurious effects can scarcely fail to result from the free use -of food which has lost so important a portion of its constituent -elements. Accordingly, when persons partake much -of boiled meat, they should either consume the broth with -the meat, or use it as soup on the alternate days. Vegetables -steamed in small quantities of water (this water being taken -with them), also afford a valuable addition to boiled meat. -In fact, experience seems to have suggested the advantage -of mixing carrots, parsnips, turnips, and greens with boiled -meat; but unfortunately the addition is not always made in -a proper manner. If the vegetables are boiled separately -in large quantities of water, and served up after this water -has been thrown away, more harm than good is done by the -addition; since the appetite is satisfied with comparatively<span class="pagenum"><a id="Page_343">343</a></span> -useless food, instead of being left free to choose, as it might -otherwise do, such forms of food as would best supply the -requirements of the system. Salads and uncooked fruits, -for instance, contain saline ingredients in large proportion, -and could be used advantageously after a meal of boiled -meat. Potatoes are likewise a valuable article of food on -account of the mineral elements contained in them. And -there can be no doubt that the value of potatoes as an article -of food is largely increased when they are cooked in their -skins, after the Irish fashion.</p> - -<p>Lastly, we must consider those articles of food which -promote the natural vital changes, but do not themselves -come to form part of the frame, or, at least, not in any large -proportion of their bulk. Such are tea, coffee, and cocoa: -alchoholic drinks; narcotics; and lastly, spices and condiments. -We may compare the use of these articles of food -to that of oil in lubricating various parts of a steam-engine. -For, as the oil neither forms part of the heat-supply nor of -the force-supply of the steam-engine, nor is used to replace -the worn material of its structure, yet serves to render the -movements of the machine more equable and effective, so -the forms of food we are considering are neither heat-producing -nor flesh-forming, nor do they serve to replace, to -any great extent, the mineral constituents of the body, yet -they produce a sense of refreshment accompanied with renewed -vigour. It is difficult to determine in what precise -way these effects are produced, but no doubt can exist as to -the fact that they are really attributable to the forms of food -to which we have assigned them.</p> - -<p>Tea, coffee, and cocoa owe their influence on the nervous -system to the presence of a substance which has received the -various names of <em>theine</em>, <em>caffeine</em>, and <em>theobromine</em>. It is -identical in composition with <em>piperine</em>, the most important -ingredient in pepper. It may be separated in the form of -delicate white, silky crystals, which have a bitter taste. In -its concentrated form this substance is poisonous, and to -this circumstance must be ascribed the ill effects which follow<span class="pagenum"><a id="Page_344">344</a></span> -from the too free use of strong tea or coffee. However, the -instances of bad effects resulting from the use of “the cup -which cheers but not inebriates” are few and far between, -while the benefits derived from it are recognized by all. -It has, indeed, been stated that no nation which has begun -to make use of tea, coffee, or cocoa, has ever given up the -practice; and no stronger evidence can be required of the -value of those articles of food.</p> - -<p>Of alcoholic liquors it is impossible to speak so favourably. -They are made use of, indeed, almost as extensively -as tea or coffee; they have been made the theme of the -poet, and hailed as the emblems of all that is genial and -convivial. Yet there can be little doubt that, when a -balance is struck between the good and evil which have -resulted to man from their use, the latter is found largely to -preponderate. The consideration of these evils belongs, -however, rather to the moralist than to the physiologist. I -have here simply to consider alcoholic liquors as articles of -food. There can be little doubt that, when used with -caution and judgment, they afford in certain cases an important -adjunct to those articles which are directly applied -to the reparation of bodily waste. Without absolutely -nourishing the frame, they ultimately lead to this end by -encouraging the digestive processes which result in the -assimilation of nutritive articles of food. But the quantity -of alcohol necessary to effect this is far less than is usually -taken even by persons who are termed temperate. It is -also certain that hundreds make use of alcoholic liquors -who have no necessity for them, and who would be better -without them. Those who require them most are men who -lead a studious sedentary life; and it is such men, also, -who suffer most from excess in the use of alcoholic liquors.</p> - -<p>It remains that I should make a few remarks on mistakes -respecting the quantity of food.</p> - -<p>Some persons fall into the habit of taking an excessive -quantity of food, not from greediness, but from the idea -that a large amount of food is necessary for the maintenance<span class="pagenum"><a id="Page_345">345</a></span> -of their strength. They thus overtax the digestive organs, -and not only fail of their purpose, but weaken instead of -strengthening the system. Especially serious is the mistake -often made by persons in delicate health of swallowing—no -other word can be used, for the digestive organs altogether -refuse to respond to the action of the mouth—large -quantities of some concentrated form of food, such as even -the strongest stomach could not deal with in that form. I -knew a person who, though suffering from weakness such -as should have suggested the blandest and simplest forms -of food, adopted as a suitable breakfast mutton-chops and -bottled stout, arguing, when remonstrated with, that he required -more support than persons in stronger health. He -was simply requiring his weak digestive organs to accomplish -work which would have taxed the digestive energies -of the most stalwart labourer working daily in the open air -for many hours.</p> - -<p>On the other hand, a too abstemious diet is as erroneous -in principle as a diet in excess of the natural requirements -of the system. A diet which is simply too abstemious is -perhaps less dangerous than persistent abstinence from the -use of certain necessary forms of food. Nature generally -prevents us from injuring ourselves by unwisely diminishing -the quantity of food we take; but unfortunately she -is not always equally decided in her admonitions respecting -the quality of our food. A man may be injuring -his health through a deficiency in the amount either of the -heat-forming or of the flesh-forming food which he consumes, -and yet know nothing of the origin of the mischief. It may -also be noted that systematic abstinence, either as respects -quantity or quality of food, is much more dangerous than -an occasional fast. Indeed, it is not generally injurious -either to abstain for several days from particular articles or -forms of food, or to remain, for several hours beyond the -usual interval between meals, without food of any sort. On -the contrary, benefit often arises from each practice. The -Emperor Aurelian used to attribute the good health he<span class="pagenum"><a id="Page_346">346</a></span> -enjoyed to his habit of abstaining for a whole day, once a -month, from food of all sorts; and many have found the -Lenten rules of abstinence beneficial. As a rule, however, -change of diet is a safer measure than periodical fasting or -abstinence from either heat-producing or flesh-forming food. -It must be noticed, in conclusion, that young persons ought -not, without medical advice, to fast or abstain for any length -of time from the more important forms of food, as serious -mischief to the digestive organs frequently follows from -either course.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_347">347</a></span></p> - -<div class="chapter"> -<h2><a id="OZONE"></a><i>OZONE.</i></h2> -</div> - -<p class="in0">The singular gas termed ozone has attracted a large amount -of attention from chemists and meteorologists. The vague -ideas which were formed as to its nature when as yet it had -been but newly discovered, have given place gradually to -more definite views; and though we cannot be said to have -thoroughly mastered all the difficulties which this strange -element presents, yet we know already much that is interesting -and instructive.</p> - -<p>Let us briefly consider the history of ozone.</p> - -<p>Nine years after Priestley had discovered oxygen, Van -Marum, the electrician, noticed that when electric sparks -are taken through that gas, a peculiar odour is evolved. -Most people know this odour, since it is always to be -recognized in the neighbourhood of an electrical machine -in action. In reality, it indicates the presence of ozone in -the air. But for more than half a century after Van Marum -had noticed it, it was supposed to be the “smell of electricity.”</p> - -<p>In 1840, Schönbein began to inquire into the cause of -this peculiar odour. He presently found that it is due to -some change in the oxygen; and that it can be produced -in many ways. Of these, the simplest, and, in some respects, -the most interesting, is the following:—“Take sticks of -common phosphorus, scrape them until they have a metallic -lustre, place them in this condition under a large bell-jar, -and half-cover them with water. The air in the bell-jar is<span class="pagenum"><a id="Page_348">348</a></span> -soon charged with ozone, and a large room can readily be -supplied with ozonized air by this process.”</p> - -<p>Schönbein set himself to inquire into the properties of -this new gas, and very interesting results rewarded his researches. -It became quite clear, to begin with, that whatever -ozone may be, its properties are perfectly distinct from -those of oxygen. Its power of oxidizing or rusting metals, -for example, is much greater than that which oxygen possesses. -Many metals which oxygen will not oxidize at all, -even when they are at a high temperature, submit at once -to the influence of ozone. But the power of ozone on other -substances than metals is equally remarkable. Dr. Richardson -states that, when air is so ozonized as to be only -respirable for a short time, its destructive power is such that -gutta-percha and india-rubber tubings are destroyed by -merely conveying it.</p> - -<p>The bleaching and disinfecting powers of ozone are very -striking. Schönbein was at first led to associate them with -the qualities of chlorine gas; but he soon found that they -are perfectly distinct.</p> - -<p>It had not yet been shown whether ozone was a simple -or a compound gas. If simple, of course it could be but -another form of oxygen. At first, however, the chances -seemed against this view; and there were not wanting skilful -chemists who asserted that ozone was a compound of -the oxygen of the air with the hydrogen which forms an -element of the aqueous vapour nearly always present in the -atmosphere.</p> - -<p>It was important to set this question at rest. This was -accomplished by the labours of De la Rive and Marignac, -who proved that ozone is simply another form of oxygen.</p> - -<p>Here we touch on a difficult branch of modern chemical -research. The chemical elements being recognized as the -simplest forms of matter, it might be supposed that each -element would be unchangeable in its nature. That a compound -should admit of change, is of course a thing to be -expected. If we decompose water, for instance, into its<span class="pagenum"><a id="Page_349">349</a></span> -component elements, oxygen and hydrogen, we may look -on these gases as exhibiting water to us in another form. -And a hundred instances of the sort might be adduced, in -which, either by separating the elements of a compound, or -by re-arranging them, we obtain new forms of matter without -any real change of substance. But with an element, -the case, one would suppose, should be different.</p> - -<p>However, the physicist must take facts as he finds them; -and amongst the most thoroughly recognized chemical facts -we have this one, that elementary substances may assume -different forms. Chemists call the phenomenon allotropy. -A well-known instance of allotropy is seen in red phosphorus. -Phosphorus is one of the chemical elements; and, -as every one knows, the form in which it is usually obtained -is that of a soft, yellow, semi-transparent solid, somewhat -resembling bees’ wax in consistence, poisonous, and readily -taking fire. Red phosphorus is the same element, yet differs -wholly in its properties. It is a powder, it does not readily -take fire, and it is not poisonous.</p> - -<p>Ozone, then, is another form of oxygen. It is the only -instance yet discovered of gaseous allotropy.</p> - -<p>And now we have to deal with the difficult and still-vexed -questions of the way in which the change from oxygen -is brought about, and the actual distinction between the -two forms of the same gas. Schönbein held that common -oxygen is produced by the combination of two special forms -of oxygen—the positive and the negative, or, as he called -them, ozone and antozone. He showed that, in certain -conditions of the air, the atmospheric oxygen exhibits qualities -which are the direct reverse of those which ozone -exhibits, and are distinct from those of ordinary oxygen. -In oxygen thus negatived or antozonized, animals cannot -live any more than they can in nitrogen. The products of -decomposition are not only not destroyed as by ozone, but -seem subject to preservative influences, and speedily become -singularly offensive; dead animal matter rapidly putrefies, -and wounds show a tendency to mortification.</p> - -<p><span class="pagenum"><a id="Page_350">350</a></span> -But the theory of positive and negative forms of oxygen, -though still held by a few physicists, has gradually given -way before the advance of new and sounder modes of inquiry. -It has been proved, in the first place, that ozone is -denser than ordinary oxygen. The production of ozone is -always followed by a contraction of the gas’s volume, the -contraction being greater or less according to the amount of -oxygen which has been ozonized. Regularly as the observers—Messrs. -Andrews and Tait—converted a definite -proportion of oxygen into ozone, the corresponding contraction -followed, and as regularly was the original volume -of the gas restored when, by the action of heat, the ozone -was reconverted into oxygen.</p> - -<p>And now a very singular experiment was made by the -observers, with results which proved utterly perplexing to -them. Mercury has the power of absorbing ozone; and -the experimenters thought that if, after producing a definite -contraction by the formation of ozone, they could absorb -the ozone by means of mercury, the quantity of oxygen -which remained would serve to show them how much ozone -had been formed, and thence, of course, they could determine -the density of ozone.</p> - -<p>Suppose, for instance, that we have one hundred cubic -inches of oxygen, and that by any process we reduce it to -a combination of oxygen and ozone occupying ninety-five -cubic inches. Now, if the mercury absorbed the ozone, -and we found, say, that there only remained eighty-five -cubic inches of oxygen, we could reason in this way:—Ten -cubic inches were occupied by the ozone before the mercury -absorbed it; but these correspond to fifteen cubic inches -of oxygen; hence, ozone must be denser than oxygen in -the proportion of fifteen to ten, or three to two. And whatever -result might have followed, a real absorption of the -ozone by the mercury would have satisfactorily solved the -problem.</p> - -<p>But the result actually obtained did not admit of interpretation -in this way. The apparent absorption of the<span class="pagenum"><a id="Page_351">351</a></span> -ozone by the mercury, that is, the disappearance of the -ozone from the mixture, was accompanied by <em>no diminution -of volume at all</em>. In other words, returning to our illustrative -case, after the absorption of the ozone from the ninety-five -cubic inches occupied by the mixture, there still remained -ninety-five cubic inches of oxygen; so that it seemed as -though an evanescent volume of ozone corresponded in -weight to five cubic inches of oxygen. This solution, of -course, could not be admitted, since it made the density of -ozone <em>infinite</em>.</p> - -<p>The explanation of this perplexing experiment is full of -interest and instruction. The following is the account given -by Mr. C. W. Heaton (Professor of Chemistry at Charing -Cross Hospital), slightly modified, however, so that it may -be more readily understood.</p> - -<p>Modern chemists adopt, as a convenient mode of representing -the phenomena which gases exhibit, the theory that -every gas, whether elementary or compound, consists of -minute molecules. They suppose that these molecules are -of equal size, and are separated by equal intervals so long as -the gas remains unchanged in heat and density. This view -serves to account for the features of resemblance presented -by all gases. The features in which gases vary are accounted -for by the theory that the molecules are differently -constituted. The molecules are supposed to be clusters of -atoms, and the qualities of a gas are assumed to depend on -the nature and arrangement of these ultimate atoms. The -molecules of some elements consist but of a single atom; -the molecules of others are formed by pairs of atoms; those -of others by triplets; and so on. Again, the molecules of -compound gases are supposed to consist of combinations -of different <em>kinds</em> of atoms.</p> - -<p>Now, Dr. Odling, to whom we owe the solution of the -perplexing problem described above, thus interpreted the -observed phenomena. A molecule of oxygen contains two -atoms, one of ozone contains three, <em>and the oxidizing power -of ozone depends on the ease with which it parts with its third<span class="pagenum"><a id="Page_352">352</a></span> -atom of oxygen</em>. Thus, in the experiment which perplexed -Messrs. Andrews and Tait, the mercury only <em>seemed</em> to -absorb the ozone; in reality it converted the ozone into -oxygen by removing its third atom. And now we see how -to interpret such a result as we considered in our illustrative -case. Five cubic inches of oxygen gave up their atoms, -each atom combining with one of the remaining oxygen -doublets, so as to form a set of ozone triplets. Clearly, -then, fifteen cubic inches of oxygen were transformed into -ozone. They now occupied but ten cubic inches; so that -the mixture, or ozonized oxygen, contained eighty-five cubic -inches of oxygen and ten of ozone. When the mercury was -introduced, it simply transformed all the ozone triplets into -oxygen doublets, by taking away the odd atom from each. -It thus left ten cubic inches of oxygen, which, with the remaining -eighty-five, constituted the ninety-five cubic inches -observed to remain after the supposed absorption of the -ozone.</p> - -<p>It follows, of course, that ozone is half as heavy again as -oxygen.</p> - -<p>But, as Mr. Heaton remarked, “this beautiful hypothesis, -although accounting perfectly for all known facts, was -yet but a probability. One link was lacking in the chain of -evidence, and that link M. Soret has supplied by a happily -devised experiment.” Although mercury and most substances -are only capable of converting ozone into oxygen, -oil of turpentine has the power of absorbing ozone in its -entirety. Thus, when the experiment was repeated, with oil -of turpentine in place of the mercury, the ozone was -absorbed, and the remaining oxygen, instead of occupying -ninety-five inches, occupied but eighty-five. After this, no -doubt could remain that Dr. Odling’s ingeniously conceived -hypothesis was the correct explanation of Messrs. Andrews -and Tait’s experiment.</p> - -<p>We recognize, then, in ozone a sort of concentrated -oxygen, with this peculiar property, that it possesses an extraordinary -readiness to part with its characteristic third<span class="pagenum"><a id="Page_353">353</a></span> -atom, and so disappear <em>as ozone</em>, two-thirds of its weight -remaining as oxygen.</p> - -<p>It is to this peculiarity that ozone owes the properties -which render it so important to our welfare. We are indeed, -as yet, in no position to theorize respecting this element, -our knowledge of its very existence being so recent, and our -information respecting its presence in our atmosphere being -of still more recent acquisition.</p> - -<p>Indeed, it is well remarked by Mr. Heaton, that we -had, until quite lately, no reason for confidently adopting -Schönbein’s view that ozone exists in our atmosphere. The -test-papers which Schönbein made use of turned blue under -the influence of ozone, it is true, but they were similarly influenced -by other elements which are known to exist in our -atmosphere, and even the sun’s rays turned them blue. -However, Dr. Andrews has shown how the character of the -air producing the change can be further tested, so as to -render it certain that ozone only has been at work. If -air which colours the test-papers be found to lose the property -after being heated, the change can only be due to -ozone, because nitrous and nitric acids (which have the -power of colouring the test-papers) would not be removed by -the heat, whereas ozone is changed by heat into oxygen.</p> - -<p>Once we are certain that ozone exists in the air, we -must recognize the fact that its presence cannot fail to have -an important bearing on our health and comfort; for ozone -is an exceedingly active agent, and cannot exist anywhere -without setting busily to its own proper work. What that -work is, and whether it is beneficial or deleterious to ourselves, -remains to be considered.</p> - -<p>In the first place, ozone has immense power as a disinfectant. -It decomposes the products emanating from putrefying -matter more effectually than any other known element. -Perhaps the most striking proof ever given of its qualities in -this respect is that afforded by an experiment conducted by -Dr. Richardson a few years ago.</p> - -<p>He placed a pint of blood taken from an ox in a large<span class="pagenum"><a id="Page_354">354</a></span> -wide-mouthed bottle. The blood had then coagulated, and -it was left exposed to the air until it had become entirely -redissolved by the effects of decomposition. At the end of -a year the blood was put into a stoppered bottle, and set -aside for seven years. “The bottle was then taken from its -hiding-place,” says Dr. Richardson, “and an ounce of the -blood was withdrawn. The fluid was so offensive as to produce -nausea when the gases evolved from it were inhaled. -It was subjected by Dr. Wood and myself to a current of -ozone. For a few minutes the odour of ozone was destroyed -by the odour of the gases from the blood; gradually the -offensive smell passed away; then the fluid mass became -quite sweet, and at last a faint odour of ozone was detected, -whereupon the current was stopped. The blood was thus -entirely deodorized; but another and most singular phenomenon -was observed. The dead blood coagulated as the -products of decomposition were removed, and this so perfectly, -that from the new clot that was formed serum exuded. -Before the experiment commenced, I had predicted on -theoretical grounds that secondary coagulation would follow -on purification; and this experiment, as well as several -others afterwards performed, verified the truth of the prediction.”</p> - -<p>It will of course be understood that ozone, in thus acting -as a disinfectant, is transformed into oxygen. It parts with -its third atom as in the mercury experiment, and so loses -its distinctive peculiarity. Thus we might be led to anticipate -the results which come next to be considered.</p> - -<p>Ozone has certain work to do, and in doing that work -is transmuted into oxygen. It follows, then, that where -there has been much work for ozone to do, there we shall -find little ozone left in the air. Hence, in open spaces where -there is little decomposing matter, we should expect to find -more ozone than in towns or cities. This accords with what -is actually observed. And not only is it found that country -air contains more ozone than town air, but it is found that -air which has come from the sea has more ozone than even<span class="pagenum"><a id="Page_355">355</a></span> -the country air, while air in the crowded parts of large cities -has no ozone at all, nor has the air of inhabited rooms.</p> - -<p>So far as we have gone, we might be disposed to speak -unhesitatingly in favour of the effects produced by ozone. -We see it purifying the air which would otherwise be loaded -by the products of decomposing matter, we find it present in -the sea air and the country air which we know to be so -bracing and health-restoring after a long residence in town, -and we find it absent just in those places which we look -upon as most unhealthy.</p> - -<p>Again, we find further evidence of the good effects of -ozone in the fact that cholera and other epidemics never -make their dreaded appearance in the land when the air is -well supplied with ozone—or in what the meteorologists call -“the ozone-periods.” And though we cannot yet explain -the circumstance quite satisfactorily, we yet seem justified -in ascribing to the purifying and disinfecting qualities of -ozone our freedom at those times from epidemics to which -cleanliness and good sanitary regulations are notedly -inimical.</p> - -<p>But there is a reverse side to the picture. And as we -described an experiment illustrating the disinfecting qualities -of ozone before describing the good effects of the element, -we shall describe an experiment illustrating certain less -pleasing qualities of ozone, before discussing the deleterious -influences which it seems capable of exerting.</p> - -<p>Dr. Richardson found that when the air of a room was -so loaded with ozone as to be only respirable with difficulty, -animals placed in the room were affected in a very singular -manner. “In the first place,” he says, “all the symptoms -of nasal catarrh and of irritation of the mucous membranes -of the nose, the mouth, and the throat were rapidly induced. -Then followed free secretion of saliva and profuse action -of the skin—perspiration. The breathing was greatly -quickened, and the action of the heart increased in proportion.” -When the animals were suffered to remain yet -longer within the room, congestion of the lungs followed,<span class="pagenum"><a id="Page_356">356</a></span> -and the disease called by physicians “congestive bronchitis” -was set up.</p> - -<p>A very singular circumstance was noticed also as to the -effects of ozone on the different orders of animals. The -above-mentioned effects, and others which accompanied -them, the description of which would be out of place in -these pages, were developed more freely in carnivorous than -in herbivorous animals. Rats, for example, were much -more easily influenced by ozone than rabbits were.</p> - -<p>The results of Dr. Richardson’s experiments prepare us -to hear that ozone-periods, though characterized by the -absence of certain diseases, bring with them their own forms -of disease. Apoplexy, epilepsy, and other similar diseases -seem peculiarly associated with the ozone-periods, insomuch -that eighty per cent. of the deaths occurring from them take -place on days when ozone is present in the air in larger -quantities than usual. Catarrh, influenza, and affections of -the bronchial tubes, also affect the ozone-periods.</p> - -<p>We see, then, that we have much yet to learn respecting -ozone before we can pronounce definitively whether it is more -to be welcomed or dreaded. We must wait until the researches -which are in progress have been carried out to their -conclusion, and perhaps even then further modes of inquiry -will have to be pursued before we can form a definite -opinion.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_357">357</a></span></p> - -<div class="chapter"> -<h2><a id="DEW"></a><i>DEW.</i></h2> -</div> - -<p class="in0">There are few phenomena of common occurrence which -have proved more perplexing to philosophers than those -which attend the deposition of dew. Every one is familiar -with these phenomena, and in very early times observant -men had noticed them; yet it is but quite recently that the -true theory of dew has been put forward and established. -This theory affords a striking evidence of the value of careful -and systematic observation applied even to the simplest -phenomena of nature.</p> - -<p>It was observed, in very early times, that dew is only -formed on clear nights, when, therefore, the stars are shining. -It was natural, perhaps, though hardly philosophical, to conclude -that dew is directly shed down upon the earth from -the stars; accordingly, we find the reference of dew to stellar -influences among the earliest theories propounded in explanation -of the phenomenon.</p> - -<p>A theory somewhat less fanciful, but still depending on -supposed stellar influences, was shortly put forward. It -was observed that dew is only formed when the atmosphere -is at a low temperature; or, more correctly, when the air -is at a much lower temperature than has prevailed during -the daytime. Combining this peculiarity with the former -ancient philosophers reasoned in the following manner: -Cold generates dew, and dew appears only when the skies -are clear—that is, when the stars are shining; hence it -follows that the stars generate cold, and thus lead indirectly<span class="pagenum"><a id="Page_358">358</a></span> -to the formation of dew. Hence arose the singular theory, -that as the sun pours down heat upon the earth, so the stars -(and also the moon and planets) pour down cold.</p> - -<p>Nothing is more common—we may note in passing—than -this method of philosophizing, especially in all that -concerns weather-changes; and perhaps it would be impossible -to find a more signal instance of the mistakes into -which men are likely to fall when they adopt this false -method of reasoning; for, so far is it from being true that -the stars shed cold upon the earth, that the exact reverse -is the case. It has been established by astronomers and -physicists that an important portion of the earth’s heat-supply -is derived from the stars.</p> - -<p>Following on these fanciful speculations came Aristotle’s -theory of dew—celebrated as one of the most remarkable -instances of the approximation which may sometimes be -made to the truth by clever reasoning on insufficient observations. -For we must not fall into the mistake of supposing, -as many have done, that Aristotle framed hypotheses -without making observations; indeed, there has seldom -lived a philosopher who has made more observations than -he did. His mistake was that he extended his observations -too widely, not making enough on each subject. He -imagined that, by a string of syllogisms, he could make -a few supply the place of many observations.</p> - -<p>Aristotle added two important facts to our knowledge -respecting dew—namely, first, that dew is only formed in -serene weather; and secondly, that it is not formed on the -summits of mountains. Modern observations show the -more correct statement of the case to be that dew is -<em>seldom</em> formed either in windy weather or on the tops of -mountains. Now, Aristotle reasoned in a subtle and able -manner on these two observations. He saw that dew must -be the result of processes which are interfered with when -the air is agitated, and which do not extend high above -the earth’s surface; he conjectured, therefore, that dew is -simply caused by the discharge of vapour from the air.<span class="pagenum"><a id="Page_359">359</a></span> -“Vapour is a mixture,” he said, “of water and heat, and as -long as water can get a supply of heat, vapour rises. But -vapour cannot rise high, or the heat would get detached -from it; and vapour cannot exist in windy weather, but -becomes dissipated. Hence, in high places, and in windy -weather, dew cannot be formed for want of vapour.” He -derided the notion that the stars and moon cause the precipitation -of dew. “On the contrary, the sun,” he said, -“is the cause; since its heat raises the vapour, from which -the dew is formed when that heat is no longer present to -keep up the vapour.”</p> - -<p>Amidst much that is false, there is here a good deal that -is sound. The notion that heat is some substance which -floats up the vapour, and may become detached from it in -high or windy places, is of course incorrect. So also is the -supposition that the dew is produced by the <em>fall</em> of condensed -vapour as the heat passes away. Nor is it correct -to say that the absence of the sun causes the condensation -of vapour, since, as we shall presently see, the cold which -causes the deposition of dew results from more than the -mere absence of the sun. But, in pointing out that the -discharge of vapour from the air, owing to loss of heat, is -the true cause of the deposition of dew, Aristotle expressed -an important truth. It was when he attempted to account -for the discharge that he failed. It will be observed, also, -that his explanation does not account for the observed fact -that dew is only formed in clear weather.</p> - -<p>Aristotle’s views did not find acceptance among the -Greeks or Romans; they preferred to look on the moon, -stars, and planets as the agents which cause the deposition -of dew. “This notion,” says a modern author, “was too -beautiful for a Greek to give up, and the Romans could not -do better than follow the example of their masters.”</p> - -<p>In the middle ages, despite the credit attached to -Aristotle’s name, those who cultivated the physical sciences -were unwilling to accept his views; for the alchemists (who -alone may be said to have been students of nature) founded<span class="pagenum"><a id="Page_360">360</a></span> -their hopes of success in the search for the philosopher’s -stone, the <i xml:lang="la" lang="la">elixir vitæ</i>, and the other objects of their pursuit, -on occult influences supposed to be exercised by the celestial -bodies. It was unlikely, therefore, that they would willingly -reject the ancient theory which ascribed dew to lunar and -stellar radiations.</p> - -<p>But at length Baptista Porta adduced evidence which -justified him in denying positively that the moon or stars -exercise any influence on the formation of dew. He discovered -that dew is sometimes deposited on the inside of -glass panes; and again, that a bell-glass placed over a plant -in cold weather is more copiously covered with dew within -than without; nay, he observed that even some opaque -substances show dew on their <em>under</em> surface when none -appears on the upper. Yet, singularly enough, Baptista -Porta rejected that part of Aristotle’s theory which was -alone correct. He thought his observations justified him in -looking on dew as condensed—not from vapour, as Aristotle -thought—but from the air itself.</p> - -<p>But now a new theory of dew began to be supported. -We have seen that not only the believers in stellar influence, -but Aristotle also, looked on dew as falling from above. -Porta’s experiments were opposed to this view. It seemed -rather as if dew rose from the earth. Observation also -showed that the amount of dew obtained at different heights -from the ground diminishes with the height. Hence, the -new theorists looked upon dew as an exhalation from the -ground and from plants—a fine steam, as it were, rising -upwards, and settling principally on the under surfaces of -objects.</p> - -<p>But this view, like the others, was destined to be overthrown. -Muschenbroek, when engaged in a series of observations -intended to establish the new view, made a -discovery which has a very important bearing on the theory of -dew: he found that, instead of being deposited with tolerable -uniformity upon different substances,—as falling rain is, -for instance, and as the rising rain imagined by the new<span class="pagenum"><a id="Page_361">361</a></span> -theorists ought to be,—dew forms very much more freely on -some substances than on others.</p> - -<p>Here was a difficulty which long perplexed physicists. -It appeared that dew neither fell from the sky nor arose -from the earth. The object itself on which the dew was -formed seemed to play an important part in determining the -amount of deposition.</p> - -<p>At length it was suggested that Aristotle’s long-neglected -explanation might, with a slight change, account for the -observed phenomena. The formation of dew was now -looked upon as a discharge of vapour from the air, this discharge -not taking place necessarily upwards or downwards, -but always from the air next to the object. But it was easy -to test this view. It was understood that the coldness of the -object, as compared with the air, was a necessary element -in the phenomenon. It followed, that if a cold object is -suddenly brought into warm air, there ought to be a deposition -of moisture upon the object. This was found to be the -case. Any one can readily repeat the experiment. If a -decanter of ice-cold water is brought into a warm room, in -which the air is not dry—a crowded room, for example—the -deposition of moisture is immediately detected by the -clouding of the glass. But there is, in fact, a much simpler -experiment. When we breathe, the moisture in the breath -generally continues in the form of vapour. But if we breathe -upon a window-pane, the vapour is immediately condensed, -because the glass is considerably colder than the exhaled air.</p> - -<p>But although this is the correct view, and though physicists -had made a noteworthy advance in getting rid of -erroneous notions, yet a theory of dew still remained to be -formed; for it was not yet shown how the cold, which causes -the deposition of dew, is itself occasioned. The remarkable -effects of a clear sky and serene weather in encouraging the -formation of dew, were also still unaccounted for. On the -explanation of these and similar points, the chief interest of -the subject depends. Science owes the elucidation of these -difficulties to Dr. Wells, a London physician, who studied<span class="pagenum"><a id="Page_362">362</a></span> -the subject of dew in the commencement of the present century. -His observations were made in a garden three miles -from Blackfriars Bridge.</p> - -<p>Wells exposed little bundles of wool, weighing, when -dry, ten grains each, and determined by their increase in -weight the amount of moisture which had been deposited -upon them. At first, he confined himself to comparing the -amount of moisture collected on different nights. He found -that although it was an invariable rule that cloudy nights -were unfavourable to the deposition of dew, yet that on some -of the very clearest and most serene nights, less dew was -collected than on other occasions. Hence it became evident -that mere clearness was not the only circumstance which -favoured the deposition of dew. In making these experiments, -he was struck by results which appeared to be -anomalous. He soon found that these anomalies were -caused by any obstructions which hid the heavens from his -wool-packs: such obstructions hindered the deposition of -dew. He tried a crucial experiment. Having placed a -board on four props, he laid a piece of wool <em>on</em> the board, -and another <em>under</em> it. During a clear night, he found that -the difference in the amount of dew deposited on the two -pieces of wool was remarkable: the upper one gained fourteen -grains in weight, the lower one gained only four grains. -He made a little roof over one piece of wool, with a sheet of -pasteboard; and the increase of weight was reduced to two -grains, while a piece of wool outside the roof gained no less -than sixteen grains in weight.</p> - -<p>Leaving these singular results unexplained for a while, -Dr. Wells next proceeded to test the temperature near his -wool-packs. He found that where dew is most copiously -produced, there the temperature is lowest. Now, since it is -quite clear that the deposition of dew was not the cause of -the increased cold—for the condensation of vapour is a process -<em>producing heat</em>—it became quite clear that the formation -of dew is dependent on and proportional to the loss of -heat.</p> - -<p><span class="pagenum"><a id="Page_363">363</a></span> -And now Wells was approaching the solution of the -problem he had set himself; for it followed from his observations, -that such obstructions as the propped board and the -pasteboard roof <em>kept in the heat</em>. It followed also, from the -observed effects of clear skies, that clouds <em>keep in the heat</em>. -Now, what sort of heat is that which is prevented from -escaping by the interference of screens, whether material or -vaporous? There are three processes by which heat is -transmitted from one body to another,—these are, conduction, -convection, and radiation. The first is the process by -which objects in contact communicate their heat to each -other, or by which the heat in one part of a body is gradually -transmitted to another part. The second is the process by -which heat is carried from one place to another by the absolute -transmission of heated matter. The third is that process -by which heat is spread out in all directions, in the -same manner as light. A little consideration will show that -the last process is that with which we are alone concerned; -and this important result flows from Dr. Wells’ experiments, -that <em>the rate of the deposition of dew depends on the rate at -which bodies part with their heat by radiation</em>. If the process -of radiation is checked, dew is less copiously deposited, and -<i xml:lang="la" lang="la">vice versâ</i>.</p> - -<p>When we consider the case of heat accompanied by -light, we understand readily enough that a screen may interfere -with the emission of radiant heat. We use a fire-screen, -for instance, with the object of producing just such an interference. -But we are apt to forget that what is true of -luminous heat is true also of that heat which every substance -possesses. In fact, we do not meet with many instances in -which the effect of screens in preventing the loss of obscure -heat is very noteworthy. There are some, as the warmth of -a green-house at night, and so on; but they pass unnoticed, -or are misunderstood. It was in this way that the explanation -of dew-phenomena had been so long delayed. The -very law on which it is founded had been <em>practically</em> applied, -while its meaning had not been recognized. “I had often<span class="pagenum"><a id="Page_364">364</a></span> -in the pride of half-knowledge,” says Wells, “smiled at the -means frequently employed by gardeners to protect tender -plants from cold, as it appeared to me impossible that a thin -mat, or any such flimsy substance, could prevent them from -attaining the temperature of the atmosphere, by which alone -I thought them liable to be injured. But when I had seen -that bodies on the surface of the earth become, during a still -and serene night, colder than the atmosphere, by radiating -their heat to the heavens, I perceived immediately a just -reason for the practice which I had before deemed useless.”</p> - -<p>And now all the facts which had before seemed obscure -were accounted for. It had been noticed that metallic plates -were often dry when grass or wood was copiously moistened. -Now, we know that metals part unwillingly with their heat -by radiation, and therefore the temperature of a metal plate -exposed in the open air is considerably higher than that of -a neighbouring piece of wood. For a similar reason, dew is -more freely deposited on grass than on gravel. Glass, again, -is a good radiator, so that dew is freely deposited on glass -objects,—a circumstance which is very annoying to the telescopist. -The remedy employed is founded on Wells’ observations—a -cylinder of tin or card, called a dew-cap, is made -to project beyond the glass, and thus to act as a screen, and -prevent radiation.</p> - -<p>We can now also interpret the effects of a clear sky. -Clouds act the part of screens, and check the emission of -radiant heat from the earth. This fact has been noticed -before, but misinterpreted, by Gilbert White of Selborne. -“I have often observed,” he says, “that cold seems to descend -from above; for when a thermometer hangs abroad on a -frosty night, the intervention of a cloud shall immediately raise -the mercury ten degrees, and a clear sky shall again compel -it to descend to its former gauge.” Another singular mistake -had been made with reference to the power which clouds -possess of checking the emission of radiant heat. It had -been observed that on moonlit nights the eyes are apt to -suffer in a peculiar way, which has occasionally brought on<span class="pagenum"><a id="Page_365">365</a></span> -temporary blindness. This had been ascribed to the moon’s -influence, and the term moon-blindness had therefore been -given to the affection. In reality, the moon has no more to -do with this form of blindness than the stars have to do with -the formation of dew. The absence of clouds from the air -is the true cause of the mischief. There is no sufficient -check to the radiation of heat from the eyeballs, and the -consequent chill results in temporary loss of sight, and sometimes -even in permanent injury.</p> - -<p>Since clouds possess this important power, it is clear that -while they are present in the air there can never be a copious -formation of dew, which requires, as we have seen, a considerable -fall in the temperature of the air around the place -of deposition. When the air is clear, however, radiation -proceeds rapidly, and therefore dew is freely formed.</p> - -<p>But it might seem that since objects in the upper regions -of the air part with their radiant heat more freely than -objects on the ground, the former should be more copiously -moistened with dew than the latter. That the fact is exactly -the reverse is thus explained. The cold which is produced -by the radiation of heat from objects high in the air is communicated -to the surrounding air, which, growing heavier, -descends towards the ground, its place being supplied by -warmer air. Thus the object is prevented from reducing the -air in its immediate neighbourhood to so low a temperature -as would be attained if this process of circulation were -checked. Hence, a concave vessel placed below an object -high in air, would serve to increase the deposition of dew by -preventing the transfer of the refrigerated air. We are not -aware that the experiment has ever been tried, but undoubtedly -it would have the effect we have described. An object -on the ground grows cold more rapidly, because the neighbouring -air cannot descend after being chilled, but continues -in contact with the object; also cold air is continually -descending from the neighbourhood of objects higher in air -which are parting with their radiant heat, and the cold air -thus descending takes the place of warmer air, whose neighbourhood<span class="pagenum"><a id="Page_366">366</a></span> -might otherwise tend to check the loss of heat in -objects on the ground.</p> - -<p>Here, also, we recognize the cause of the second peculiarity -detected by Aristotle—namely, that dew is only -formed copiously in serene weather. When there is wind, -it is impossible that the refrigerated air around an object -which is parting with its radiant heat, can remain long in -contact with the object. Fresh air is continually supplying -the place of the refrigerated air, and thus the object is prevented -from growing so cold as it otherwise would.</p> - -<p>In conclusion, we should wish to point out the important -preservative influence exercised during the formation of dew. -If the heat which is radiated from the earth, or from objects -upon it, during a clear night, were not repaired in any way, -the most serious injury would result to vegetation. For -instance, if the sun raised no vapour during the day, so that -when night came on the air was perfectly dry, and thus the -radiant heat passed away into celestial space without compensation, -not a single form of vegetation could retain its -life during the bitter cold which would result. But consider -what happens. The sun’s heat, which has been partly used -up during the day in supplying the air with aqueous vapour, -is gradually given out as this vapour returns to the form -of water. Thus the process of refrigeration is effectually -checked, and vegetation is saved from destruction. There -is something very beautiful in this. During the day, the -sun seems to pour forth his heat with reckless profusion, -yet all the while it is being silently stored up; during the -night, again, the earth seems to be radiating her heat too -rapidly into space, yet all the while a process is going on by -which the loss of heat is adequately compensated. Every -particle of dew which we brush from the blades of grass, as -we take our morning rambles, is an evidence of the preservative -action of nature.</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_367">367</a></span></p> - -<div class="chapter"> -<h2><a id="THE_LEVELLING_POWER_OF_RAIN"></a><i>THE LEVELLING POWER OF RAIN.</i></h2> -</div> - -<p class="in0">It has been recognized, ever since geology has become truly -a science, that the two chief powers at work in remodelling -the earth’s surface, are fire and water. Of these powers one -is in the main destructive, and the other preservative. Were -it not for the earth’s vulcanian energies, there can be no -question that this world would long since have been rendered -unfit for life,—at least of higher types than we recognize -among sea creatures. For at all times igneous causes -are at work, levelling the land, however slowly; and this not -only by the action of sea-waves at the border-line between -land and water, but by the action of rain and flood over -inland regions. Measuring the destructive action of water -by what goes on in the lifetime of a man, or even during -many successive generations, we might consider its effects -very slight, even as on the other hand we might underrate -the effects of the earth’s internal fires, were we to limit our -attention to the effects of upheaval and of depression (not -less preservative in the long run) during a few hundreds or -thousands of years. As Lyell has remarked in his “Principles -of Geology,” “our position as observers is essentially unfavourable -when we endeavour to estimate the nature and -magnitude of the changes now in progress. As dwellers on -the land, we inhabit about a fourth part of the surface; and -that portion is almost exclusively a theatre of decay, and not -of reproduction. We know, indeed, that new deposits are -annually formed in seas and lakes, and that every year some<span class="pagenum"><a id="Page_368">368</a></span> -new igneous rocks are produced in the bowels of the earth, -but we cannot watch the progress of their formation; and as -they are only present to our minds by the aid of reflection, -it requires an effort both of the reason and the imagination -to appreciate duly their importance.” But that they are -actually of extreme importance, that in fact all the most -characteristic features of our earth at present are due to the -steady action of these two causes, no geologist now doubts.</p> - -<p>I propose now to consider one form in which the earth’s -aqueous energies effect the disintegration and destruction of -the land. The sea destroys the land slowly but surely, by -beating upon its shores and by washing away the fragments -shaken down from cliffs and rocks, or the more finely divided -matter abstracted from softer strata. In this work the sea is -sometimes assisted by the other form of aqueous energy—the -action of rain. But in the main, the sea is the destructive -agent by which shore-lines are changed. The other way in -which water works the destruction of the land affects the -interior of land regions, or only affects the shore-line by -removing earthy matter from the interior of continents to the -mouths of great rivers, whence perhaps the action of the sea -may carry it away to form shoals and sandbanks. I refer to -the direct and indirect effects of the downfall of rain. All -these effects, without a single exception, tend to level the -surface of the earth. The mountain torrent whose colour -betrays the admixture of earthy fragments is carrying those -fragments from a higher to a lower level. The river owes its -colour in like manner to earth which it is carrying down to -the sea level. The flood deposits in valleys matter which -has been withdrawn from hill slopes. Rainfall, acts, however, -in other ways, and sometimes still more effectively. -The soaked slopes of great hills give way, and great landslips -occur. In winter the water which has drenched the land -freezes, in freezing expands, and then the earth crumbles -and is ready to be carried away by fresh rains; or when dry, -by the action even of the wind alone. Landslips, too, are -brought about frequently in the way, which are even more<span class="pagenum"><a id="Page_369">369</a></span> -remarkable than those which are caused by the unaided -action of heavy rainfalls.</p> - -<p>The most energetic action of aqueous destructive forces -is seen when water which has accumulated in the higher -regions of some mountain district breaks its way through -barriers which have long restrained it, and rushes through -such channels as it can find or make for itself into valleys -and plains at lower levels. Such catastrophes are fortunately -not often witnessed in this country, nor when seen do they -attain the same magnitude as in more mountainous countries. -It would seem, indeed, as though they could attain very -great proportions only in regions where a large extent of -mountain surface lies above the snow-line. The reason why -in such regions floods are much more destructive than elsewhere -will readily be perceived if we consider the phenomena -of one of these terrible catastrophes.</p> - -<p>Take, for instance, the floods which inundated the plains -of Martigny in 1818. Early in that year it was found that -the entire valley of the Bagnes, one of the largest side-valleys -of the great valley of the Rhône, above Geneva, had been -converted into a lake through the damming up of a narrow -outlet by avalanches of snow and ice from a loftier glacier -overhanging the bed of the river Dranse. The temporary -lake thus formed was no less than half a league in length, -and more than 200 yards wide, its greatest depth exceeding -200 feet. The inhabitants perceived the terrible effects which -must follow when the barrier burst, which it could not fail to -do in the spring. They, therefore, cut a gallery 700 feet long -through the ice, while as yet the water was at a moderate -height. When the waters began to flow through this channel, -their action widened and deepened it considerably. At length -nearly half the contents of the lake were poured off. Unfortunately, -as the heat of the weather increased, the middle -of the barrier slowly melted away, until it became too weak to -withstand the pressure of the vast mass of water. Suddenly -it gave way; and so completely that all the water in the lake -rushed out in half an hour. The effects of this tremendous<span class="pagenum"><a id="Page_370">370</a></span> -outrush of the imprisoned water were fearful. “In the course -of their descent,” says one account of the catastrophe, “the -waters encountered several narrow gorges, and at each of -these they rose to a great height, and then burst with new -violence into the next basin, sweeping along forests, houses, -bridges, and cultivated land.” It is said by those who witnessed -the passage of the flood at various parts of its course, -that it resembled rather a moving mass of rock and mud -than a stream of water. “Enormous masses of granite were -torn out of the sides of the valleys, and whirled for hundreds -of yards along the course of the flood.” M. Escher the -engineer tells us that a fragment thus whirled along was -afterwards found to have a circumference of no less than -sixty yards. “At first the water rushed on at a rate of more -than a mile in three minutes, and the whole distance (forty-five -miles) which separates the Valley of Bagnes from the Lake -of Geneva was traversed in little more than six hours. The -bodies of persons who had been drowned in Martigny were -found floating on the further side of the Lake of Geneva, near -Vevey. Thousands of trees were torn up by the roots, and -the ruins of buildings which had been overthrown by the -flood were carried down beyond Martigny. In fact, the -flood at this point was so high, that some of the houses in -Martigny were filled with mud up to the second story.”</p> - -<p>It is to be noted respecting this remarkable flood, that -its effects were greatly reduced in consequence of the efforts -made by the inhabitants of the lower valleys to make an -outlet for the imprisoned waters. It was calculated by M. -Escher that the flood carried down 300,000 cubic feet of -water every second, an outflow five times as great as that of -the Rhine below Basle. But for the drawing off of the -temporary lake, the flood, as Lyell remarks, would have -approached in volume some of the largest rivers in Europe. -“For several months after the <i xml:lang="fr" lang="fr">débâcle</i> of 1818,” says Lyell, -“the Dranse, having no settled channel, shifted its position -continually from one side to the other of the valley, carrying -away newly erected bridges, undermining houses, and<span class="pagenum"><a id="Page_371">371</a></span> -continuing to be charged with as large a quantity of earthy -matter as the fluid could hold in suspension. I visited this -valley four months after the flood, and was witness to the -sweeping away of a bridge and the undermining of part of a -house. The greater part of the ice-barrier was then standing, -presenting vertical cliffs 150 feet high, like ravines in the -lava-currents of Etna, or Auvergne, where they are intersected -by rivers.” It is worthy of special notice that inundations -of similar or even greater destructiveness have occurred in -the same region at former periods.</p> - -<p>It is not, however, necessary for the destructive action of -floods in mountain districts that ice and snow should assist, -as in the Martigny flood. In October, 1868, the cantons of -Tessin, Grisons, Uri, Valois, and St. Gall, suffered terribly -from the direct effects of heavy rainfall. The St. Gothard, -Splugen, and St. Bernhardin routes were rendered impassable. -In the former pass twenty-seven lives were lost, -besides many horses and waggons of merchandise. On the -three routes more than eighty persons in all perished. In -the small village of Loderio alone, no less than fifty deaths -occurred. The damage in Tessin was estimated at £40,000. -In Uri and Valois large bridges were destroyed and carried -away. Everything attested the levelling power of rain; a -power which, when the rain is falling steadily on regions -whence it as steadily flows away, we are apt to overlook.</p> - -<p>It is not, however, necessary to go beyond our own country -for evidence of the destructive action of water. We have -had during the past few years very striking evidence in this -respect, which need scarcely be referred to more particularly -here, because it will be in the recollection of all our readers. -Looking over the annals of the last half-century only, we -find several cases in which the power of running water in -carrying away heavy masses of matter has been strikingly -shown. Consider, for instance, the effects of the flood in -Aberdeenshire and the neighbouring counties, early in -August, 1829. In the course of two days a great flood -extended itself over “that part of the north-east of Scotland<span class="pagenum"><a id="Page_372">372</a></span> -which would be cut off by two lines drawn from the head of -Loch Rannoch, one towards Inverness and the other to -Stonehaven.” The total length of various rivers in this -region which were flooded amounted to between 500 and 600 -miles. Their courses were marked everywhere by destroyed -bridges, roads, buildings, and crops. Sir T. D. Lauder -records “the destruction of thirty-eight bridges, and the -entire obliteration of a great number of farms and hamlets. -On the Nairn, a fragment of sandstone fourteen feet long -by three feet wide and one foot thick, was carried about 200 -yards down the river. Some new ravines were formed on -the sides of mountains where no streams had previously -flowed, and ancient river channels, which had never been -filled from time immemorial, gave passage to a copious -flood.” But perhaps the most remarkable effect of these -inundations was the entire destruction of the bridge over the -Dee at Ballater. It consisted of five arches, spanning a -waterway of 260 feet. The bridge was built of granite, -the pier, resting on rolled pieces of granite and gneiss. -We read that the different parts of this bridge were -swept away in succession by the flood, the whole mass of -masonry disappearing in the bed of the river. Mr. Farquharson -states that on his own premises the river Don forced -a mass of 400 or 500 tons of stones, many of them of 200 or -300 pounds’ weight, up an inclined plane, rising six feet in -eight or ten yards, and left them in a rectangular heap about -three feet deep on a flat ground, the heap ending abruptly at -its lower extremity.” At first sight this looks like an action -the reverse of that levelling action which we have here -attributed to water. But in reality it indicates the intense -energy of this action; which drawing heavy masses down -along with swiftly flowing water, communicates to them so -great a momentum, that on encountering in their course a -rising slope, they are carried up its face and there left by the -retreating flood. The rising of these masses no more -indicates an inherent uplifting power in running water, than -the ascent of a gently rising slope by a mass which has rolled<span class="pagenum"><a id="Page_373">373</a></span> -headlong down the steep side of a hill indicates an upward -action exerted by the force of gravity.</p> - -<p>Even small rivers, when greatly swollen by rain, exhibit -great energy in removing heavy masses. Thus Lyell -mentions that in August, 1827, the College, a small river -which flows down a slight declivity from the eastern watershed -of the Cheviot Hills, carried down several thousand -tons’ weight of gravel and sand to the plain of the Till. This -little river also carried away a bridge then in process of -building, “some of the arch stones of which, weighing from -half to three-quarters of a ton each, were propelled two miles -down the rivulet.” “On the same occasion the current tore -away from the abutment of a mill-dam a large block of greenstone -porphyry, weighing nearly two tons, and transported it -to a distance of nearly a quarter of a mile. Instances are -related as occurring repeatedly, in which from 1000 to 3000 -tons of gravel are in like manner removed by this streamlet -to still greater distances in one day.”</p> - -<p>It may appear, however, to the reader that we have in -such instances as these the illustration of destructive agencies -which are of their very nature limited within very narrow -areas. The torrent, or even the river, may wear out its bed -or widen it, but nevertheless can hardly be regarded as -modifying the aspect of the region through which it flows. -Even in this respect, however, the destructive action of water -is not nearly so limited as it might appear to be. Taking a -few centuries or a few thousand years, no doubt, we can -attribute to the action of rivers, whether in ordinary flow or -in flood, little power of modifying the region which they -drain. But taking that wider survey (in time) of fluviatile -work which modern science requires, dealing with this form -of aqueous energy as we deal with the earth’s vulcanian -energies, we perceive that the effects of river action in the -course of long periods of time are not limited to the course -which at any given time a river may pursue. In carrying -down material along its course to the sea, a river is not -merely wearing down its own bed, but is so changing it that<span class="pagenum"><a id="Page_374">374</a></span> -in the course of time it will become unfit to drain the region -through which it flows. Its bottom must of necessity become -less inclined. Now although it will then be lower than at -present, and therefore be then even more than now the place -to which the water falling upon the region traversed by the -river will naturally tend, it will no longer carry off that water -with sufficient velocity. Three consequences will follow -from this state of things. In the first place there will be -great destruction in the surrounding region through floods -because of inadequate outflow; in the second place, the -overflowing waters will in the course of time find new -channels, or in other words new rivers will be formed in -this region; thirdly, owing to the constant presence of large -quantities of water in the depressed bed of the old river, the -banks on either side will suffer, great landslips occurring and -choking up its now useless channel. Several rivers are -undergoing these changes at the present time, and others, -which are manifestly unfit for the work of draining the region -through which they flow (a circumstance attested by the -occurrence of floods in every wet season), must before long -be modified in a similar way.</p> - -<p>We are thus led to the consideration of the second form -in which the destructive action of inland waters, or we may -truly say, the destructive action of <em>rain</em>, is manifested,—viz., -in landslips. These, of course, are also caused not -unfrequently by vulcanian action, but equally of course landslips -so caused do not belong to our present subject. Landslips -caused directly or indirectly by rain, are often quite -as extensive as those occasioned by vulcanian energy, and -they are a great deal more common. We may cite as a -remarkable instance a landslip of nearly half a mile in -breadth, now in progress, in a district of the city of Bath -called Hedgmead, which forms a portion of the slope of -Beacon Hill. It is attributed to the action of a subterranean -stream on a bed of gravel, the continued washing away of -which causes the shifting; but the heavy rains of 1876–77 -caused the landslip to become much more marked.</p> - -<p><span class="pagenum"><a id="Page_375">375</a></span> -Besides slow landslips, however, rain not unfrequently -causes great masses of earth to be precipitated suddenly, -and where such masses fall into the bed of a river, local -deluges of great extent and of the most destructive character -often follow. The following instances, cited in an abridged -form from the pages of Lyell’s “Principles of Geology,” attest -the terrible nature of catastrophes such as these.</p> - -<p>Two dry seasons in the White Mountains of New Hampshire -were followed by heavy rains on August 28, 1826. -From the steep and lofty slopes of the River Saco great -masses of rock and stone were detached, and descending -carried along with them “in one promiscuous and frightful -ruin, forests, shrubs, and the earth which sustained them.” -“Although there are numerous indications on the steep -sides of these hills of former slides of the same kind, yet no -tradition had been handed down of any similar catastrophe -within the memory of man, and the growth of the forest on -the very spots now devastated clearly showed that for a -long interval nothing similar had occurred. One of these -moving masses was afterwards found to have slid three -miles, with an average breadth of a quarter of a mile.” At -the base of the vast chasms formed by these natural excavations, -a confused mass of ruins was seen, consisting of transported -earth, gravel, rocks, and trees. Forests were prostrated -with as much ease as if they had been mere fields of grain; -if they resisted for a while, “the torrent of mud and rock -accumulated behind till it gathered sufficient force to burst -the temporary barrier.” “The valleys of the Amonoosuck -and Saco presented, for many miles, an uninterrupted scene -of desolation, all the bridges being carried away, as well -as those over the tributary streams. In some places -the road was excavated to the depth of from fifteen to -twenty feet; in others it was covered with earth, rocks, and -trees to as great a height. The water flowed for many weeks -after the flood, as densely charged with earth as it could be -without being changed into mud, and marks were seen in -various localities of its having risen on either side of the<span class="pagenum"><a id="Page_376">376</a></span> -valley to more than twenty-five feet above the ordinary -level.” But perhaps the most remarkable evidence of the -tremendous nature of this cataclysm is to be found in Lyell’s -statements respecting the condition of the region nineteen -years later. “I found the signs of devastation still very -striking,” he says; “I also particularly remarked that the -surface of the bare granite rocks had been smoothed by -the passage over them of so much mud and stone.” Professor -Hubbard mentions in <cite>Silliman’s Journal</cite> that “in -1838 the deep channels worn by the avalanches of mud -and stone, and the immense heaps of boulders and blocks of -granite in the river channel, still formed a picturesque feature -in the scenery.”</p> - -<p>It will readily be understood that when destruction such -as this follows from landslips along the borders of insignificant -rivers, those occurring on the banks of the mighty -rivers which drain whole continents are still more terrible. -The following account from the pen of Mr. Bates the -naturalist, indicates the nature of the landslips which occur -on the banks of the Amazon. “I was awoke before sunrise, -one morning,” he says, “by an unusual sound resembling -the roar of artillery; the noise came from a considerable -distance, one crash succeeding another. I supposed it to -be an earthquake, for, although the night was breathlessly -calm, the broad river was much agitated, and the vessel -rolled heavily. Soon afterwards another loud explosion -took place, followed by others which lasted for an hour till -the day dawned, and we then saw the work of destruction -going forward on the other side of the river, about three -miles off. Large masses of forest, including trees of colossal -size, probably 200 feet in height, were rocking to and fro, -and falling headlong one after another into the water. After -each avalanche the wave which it caused returned on the -crumbly bank with tremendous force, and caused the fall -of other masses by undermining. The line of coast over -which the landslip extended was a mile or two in length; -the end of it, however, was hid from our view by an intervening<span class="pagenum"><a id="Page_377">377</a></span> -island. It was a grand sight; each downfall created a -cloud of spray; the concussion in one place causing other -masses to give way a long distance from it, and thus the -crashes continued, swaying to and fro, with little prospect of -termination. When we glided out of sight two hours after -sunrise the destruction was still going on.”</p> - -<p>We might consider here the action of glaciers in gradually -grinding down the mountain slopes, the destructive action -of avalanches, and a number of other forms in which snow -and ice break down by slow degrees the upraised portions -of the earth. For in reality all these forms of destructive -action take their origin in the same process whence running -waters and heavy rainfalls derive their power. All these -destructive agencies are derived from the vapour of water -in the air. But it seems better to limit the reader’s attention -in this place to the action of water in the liquid form; and -therefore we proceed to consider the other ways in which -rain wears down the land.</p> - -<p>Hitherto we have considered effects which are produced -chiefly along the courses of rivers, or in their neighbourhood. -But heavy rainfall acts, and perhaps in the long run as -effectively (when we remember the far wider region affected) -over wide tracts of nearly level ground, as along the banks -of torrents and rivers.</p> - -<p>The rain which falls on plains or gently undulating -surfaces, although after a while it dries up, yet to some -degree aids in levelling the land, partly by washing down -particles of earth, however slowly, to lower levels, partly by -soaking the earth and preparing a thin stratum of its upper -surface to be converted into dust, and blown away by the -wind. But it is when very heavy storms occur that the -levelling action of rain over widely extending regions can -be most readily recognized. Of this fact observant travellers -cannot fail to have had occasional evidence. Sir Charles -Lyell mentions one instance observed by him, which is -specially interesting. “During a tour in Spain,” he says, -“I was surprised to see a district of gently undulating<span class="pagenum"><a id="Page_378">378</a></span> -ground in Catalonia, consisting of red and grey sandstone, -and in some parts of red marl, almost entirely denuded of -herbage, while the roots of the pines, holm oaks, and some -other trees, were half exposed, as if the soil had been -washed away by a flood. Such is the state of the forests, -for example, between Oristo and Vich, and near San -Lorenzo. But being overtaken by a violent thunderstorm, -in the month of August, I saw the whole surface, even the -highest levels of some flat-topped hills, streaming with mud, -while on every declivity the devastation of torrents was -terrific. The peculiarities in the physiognomy of the -district were at once explained, and I was taught that, in -speculating on the greater effects which the direct action of -rain may once have produced on the surface of certain parts -of England, we need not revert to periods when the heat of -the climate was tropical.” He might have cited instances -of such storms occurring in England. For example, White, -in his delightful “Natural History of Selborne,” describes -thus the effects of a storm which occurred on June 5, 1784: -“At about a quarter after two the storm began in the parish -of Harpley, moving slowly from north to south, and from -thence it came over Norton Farm and so to Grange Farm, -both in this parish. Had it been as extensive as it was -violent (for it was very short) it must have ravaged all the -neighbourhood. The extent of the storm was about two -miles in length and one in breadth. There fell prodigious -torrents of rain on the farms above mentioned, which -occasioned a flood as violent as it was sudden, doing great -damage to the meadows and fallows by deluging the one -and washing away the soil of the other. The hollow lane -towards Alton was so torn and disordered as not to be -passable till mended, rocks being removed which weighed -two hundredweight.”</p> - -<p>We have mentioned the formation of dust, and the -action of wind upon it, as a cause tending to level the surface -of the land. It may appear to many that this cause is too insignificant -to be noticed among those which modify the earth’s<span class="pagenum"><a id="Page_379">379</a></span> -surface. In reality, however, owing to its continuous action, -and to its always acting (in the main) in one direction, this -cause is much more important than might be supposed. -We overlook its action as actually going on around us, -because in a few years, or in a few generations, it produces -no change that can be readily noticed. But in long periods -of time it changes very markedly the level of lower lands, -and that too even in cities, where means exist for removing -the accumulations of dust which are continually collecting on -the surface of the earth. We know that the remains of old -Roman roads, walls, houses, and so forth, in this country, are -found, not at the present level of the surface, but several -feet—in some cases many yards—below this level. The -same holds elsewhere, under the same conditions—that is, -where we know quite certainly that the substances thus found -underground were originally on the surface, and that there -has been neither any disturbance causing them to be -engulfed, nor any deposition of scoriæ, volcanic dust, or -other products of subterranean disturbance. We cannot -hesitate to regard this burying of old buildings as due to the -continual deposition of dust, which eventually becomes compacted -into solid earth. We know, moreover, that the -formation of dust is in the main due to rain converting -the surface layers of the earth into mud, which on drying -requires but the frictional action of heavy winds to rise in -clouds of dust. In some soils this process goes on more -rapidly than in others, as every one who has travelled much -afoot is aware. There are parts of England, for instance, -where, even in the driest summer, the daily deposition of -dust on dry and breezy days is but slight, others where in -such weather a dust layer at least a quarter of an inch in -thickness is deposited in the course of a day. If we assumed, -which would scarcely seem an exaggerated estimate, that in -the course of a single year a layer of dust averaging an inch -in thickness is deposited over the lower levels of the surface -of the land, we should find that the average depth of the -layer formed in the last thousand years would amount to no<span class="pagenum"><a id="Page_380">380</a></span> -less than eighty-three feet. Of course in inhabited places -the deposition of dust is checked, though not so much as -most persons imagine. There is not probably in this -country a single building five hundred years old, originally -built at a moderately low level, the position of whose foundation -does not attest the constant gathering of matter upon -the surface. The actual amount by which the lower levels -are raised and the higher levels diminished in the course of -a thousand years may be very much less, but that it must -amount to many feet can scarcely be questioned.</p> - -<p>And as in considering the action of rain falling over a -wide range of country, we have to distinguish between the -slow but steady action of ordinary rains and the occasional -violent action of great storms of rain, so in considering the -effects of drought following after rain which has well saturated -the land we have to distinguish between ordinarily dusty -times and occasions when in a very short time, owing to the -intensity of the heat and the violence of the wind large quantities -of dust are spread over a wide area. Darwin thus describes -the effect of such exceptional drought, as experienced in the -years 1827–1832 in Buenos Ayres:—“So little rain fell that -the vegetation, even to the thistles, failed; the brooks were -dried up, and the whole country assumed the appearance of -a dusty high road. This was especially the case in the -northern part of the province of Buenos Ayres, and the -southern part of Santa Fé.” He describes the loss of life -caused by the want of water, and many remarkable circumstances -of the drought which do not here specially concern -us. He then goes on to speak of the dust which gathered -over the open country. “Sir Woodbine Parish,” he says, -“informed me of a very curious source of dispute. The -ground being so long dry, such quantities of dust were -blown about that in this open country the landmarks became -obliterated, and people could not tell the limits of their -estates.” The dust thus scattered over the land, whether -left or removed, necessarily formed part of the solid material -brought from higher to lower levels, indirectly (in this case)<span class="pagenum"><a id="Page_381">381</a></span> -through the action of rain; for a drought can only convert -into friable matter earth which has before been thoroughly -soaked. But the action of rain, which had originally led -to the formation of these enormous masses of dust, presently -took part in carrying the dust in the form of mud to yet -lower levels. “Subsequently to the drought of 1827 to -1832,” proceeds Darwin, “a very rainy season followed, which -caused great floods. Hence it is almost certain that some -thousands of the skeletons” (of creatures whose deaths he -had described before) “were buried by the deposits of the -very next year. What could be the opinion of a geologist, -viewing such an enormous collection of bones, of all kinds of -animals and of all ages, thus embedded in one thick earthy -mass? Would he not attribute it to a flood having swept -over the surface of the land, rather than to the common -order of things?” In fact, a single great drought, followed -by a very rainy season, must in this instance, which was -however altogether exceptional, have produced a layer or -stratum such as geologists would ordinarily regard as the -work of a much longer time and much more potent disturbing -causes.</p> - -<p>It may be well to consider in this place the question -whether in reality the quantity of rain which falls now during -our winter months does not greatly exceed that which formerly -fell in that part of the year. The idea is very prevalent -that our winters have changed entirely in character in -recent times, and the fear (or the hope?) is entertained that -the change may continue in the same direction until wet and -mild winters replace altogether the cold which prevailed in -former years. There is no sufficient reason, however, for -supposing that any such change is taking place. It is, indeed, -not difficult to find in the meteorological annals of the -first half of the present century, instances of the occurrence -of several successive winters very unlike the greater number -of those which we have experienced during the last ten or -twelve years. But if we take any considerable series of -years in the last century we find the alternations of the<span class="pagenum"><a id="Page_382">382</a></span> -weather very similar to those we at present recognize. -Consider, for instance, Gilbert White’s brief summary of the -weather from 1768 onwards:—</p> - -<p>For the winter of 1768–69 we have October and the first -part of November rainy; thence to the end of 1768 alternate -rains and frosts; January and February frosty and rainy, -with gleams of fine weather; to the middle of March, wind -and rain.</p> - -<p>For the winter of 1769–70 we have October frosty, the -next fortnight rainy, the next dry and frosty. December -windy, with rain and intervals of frost (the first fortnight -very foggy); the first half of January frosty, thence to the -end of February mild hazy weather. March frosty and -brighter.</p> - -<p>For 1770–71, from the middle of October to the end of -the year, almost incessant rains; January severe frosts till -the last week, the next fortnight rain and snow, and spring -weather to the end of February. March frosty.</p> - -<p>For 1771–72, October rainy, November frost with intervals -of fog and rain, December bright mild weather with -hoar frosts; then six weeks of frost and snow, followed by -six of frost, sleet, hail, and snow.</p> - -<p>For 1772–73, October, November, and to December 22, -rain, with mild weather; to the end of 1772, cold foggy -weather; then a week of frost, followed by three of dark -rainy weather. First fortnight of February frost; thence to -the end of March misty showery weather.</p> - -<p>Passing over the winter of 1773–74, which was half -rainy, half frosty, what could more closely resemble the -winter weather we have had so much of during the last -few years, than that experienced in the winter of 1774–75? -From August 24 to the third week of November, there was -rain, with frequent intervals of sunny weather; to the end of -December, dark dripping fogs; to the end of the first fortnight -in March, rain almost every day.</p> - -<p>And so on, with no remarkable changes, until the year -1792, the last of Gilbert White’s records.</p> - -<p><span class="pagenum"><a id="Page_383">383</a></span> -If we limit our attention to any given month of winter, -we find the same mixture of cold and dry with wet and -open weather as we are familiar with at present. Take, for -instance, the month usually the most wintry of all, viz., -January. Passing over the years already considered, we -have January, 1776, dark and frosty with much snow till the -26th (at this time the Thames was frozen over), then foggy -with hoar frost; January, 1777, frosty till the 10th, then foggy -and showery; 1778, frosty till the 13th, then rainy to the -24th, then hard frost; 1779, frost and showers throughout -January; 1780, frost throughout; 1781, frost and snow to -the 25th, then rain and snow; 1782, open and mild; 1783, -rainy with heavy winds; 1784, hard frost; 1785, a thaw on -the 2nd, then rainy weather to the 28th, the rest of the -month frosty; 1786, frost and snow till January 7, then a -week mild with much rain, the next week heavy snow, and -the rest mild with frequent rain; 1787, first twenty-four -days dark moist mild weather, then four days frost, the rest -mild and showery; 1788, thirteen days mild and wet, five -days of frost, and from January 18 to the end of the month -dry windy weather; 1789, thirteen days hard frost, the rest -of the month mild with showers; 1790, sixteen days of -mild foggy weather with occasional rain, to the 21st frost, -to the 28th dark with driving rains, and the rest mild dry -weather; 1791, the whole of January mild with heavy rains; -and lastly 1792, “some hard frost in January, but mostly -wet and mild.”</p> - -<p>There is nothing certainly in this record to suggest that -any material change has taken place in our January weather -during the last eight years. And if we had given the record -of the entire winter for each of the years above dealt with -the result would have been the same.</p> - -<p>We have, in fact, very striking evidence in Gilbert -White’s account of the cold weather of December, 1784, -which he specially describes as “very extraordinary,” to -show that neither our severe nor our average winter weather -can differ materially from that which people experienced<span class="pagenum"><a id="Page_384">384</a></span> -in the eighteenth century. “In the evening of December -9,” he says, “the air began to be so very sharp that we -thought it would be curious to attend to the motions of a -thermometer; we therefore hung out two, one made by -Martin and one by Dolland” (<i xml:lang="la" lang="la">sic</i>, presumably Dollond), -“which soon began to show us what we were to expect; -for by ten o’clock they fell to twenty-one, and at eleven to -four, when we went to bed. On the 10th, in the morning -the quicksilver in Dolland’s glass was down to half a degree -below zero, and that of Martin’s, which was absurdly -graduated only to four degrees above zero, sank quite into -the brass guard of the ball, so that when the weather became -most interesting this was useless. On the 10th, at -eleven at night, though the air was perfectly still, Dolland’s -glass went down to one degree below zero!” The note of -exclamation is White’s. He goes on to speak of “this -strange severity of the weather,” which was not exceeded -that winter, or at any time during the twenty-four years of -White’s observations. Within the last quarter of a century, -the thermometer, on more than one occasion, has shown -two or three degrees below zero. Certainly the winters -cannot be supposed to have been ordinarily severer than -ours in the latter half of the last century, when we find that -thermometers, by well-known instrument makers, were so -constructed as to indicate no lower temperature than four -degrees above zero.</p> - -<p>Let us return, after this somewhat long digression, to the -levelling action of rain and rivers.</p> - -<p>If we consider this action alone, we cannot but recognize -in it a cause sufficient to effect the removal of all the higher -parts of the land to low levels, and eventually of all the -low-lying land to the sea, in the course of such periods as -geology makes us acquainted with. The mud-banks at the -mouths of rivers show only a part of what rain and river -action is doing, yet consider how enormous is the mass -which is thus carried into the sea. It has been calculated -that in a single week the Ganges alone carries away from the<span class="pagenum"><a id="Page_385">385</a></span> -soil of India and delivers into the sea twice as much solid -substance as is contained in the great pyramid of Egypt. -“The Irrawaddy,” says Sir J. Herschel, “sweeps off from -Burmah 62 cubit feet of earth in every second of time on -an average, and there are 86,400 seconds in every day, and -365 days in every year; and so on for other rivers. Nor is -there any reason to fear or hope that the rains will cease, -and this destructive process come to an end. For though -the quantity of water on the surface of the earth is probably -undergoing a slow process of diminution, small -portions of it year by year taking their place as waters under -the earth,<a id="FNanchor_44" href="#Footnote_44" class="fnanchor">44</a> yet these processes are far too slow to appreciably -affect the supply of water till a far longer period has elapsed -than that during which (in all probability) life can continue -upon the earth.</p> - -<p>When we consider the force really represented by the -downfall of rain, we need not greatly wonder that the<span class="pagenum"><a id="Page_386">386</a></span> -levelling power of rain is so effective. The sun’s heat is -the true agent in thus levelling the earth, and if we regard, -as we justly may, the action of water, whether in the form -of rain or river, or of sea-wave raised by wind or tide, as -the chief levelling and therefore destructive force at work -upon the earth, and the action of the earth’s vulcanian -energies as the chief restorative agent, then we may fairly -consider the contest as lying between the sun’s heat and the -earth’s internal heat. There can be little question as to -what would be the ultimate issue of the contest if land and -sea and air all endured or were only so far modified as they -were affected by these causes. Sun-heat would inevitably -prevail in the long run over earth-heat. But we see from -the condition of our moon how the withdrawal of water -and air from the scene must diminish the sun’s power of -levelling the irregularities of the earth’s surface. We say -advisedly <em>diminish</em>, not <em>destroy</em>; for there can be no question -that the solar heat alternating with the cold of the long -lunar night is still at work levelling, however slowly, the -moon’s surface; and the same will be the case with our -earth when her oceans and atmosphere have disappeared by -slow processes of absorption.</p> - -<p>The power actually at work at present in producing rain, -and so, indirectly, in levelling the earth’s surface, is enormous. -I have shown that the amount of heat required -to evaporate a quantity of water which would cover an area -of 100 square miles to a depth of one inch would be equal -to the heat which would be produced by the combustion -of half a million tons of coals, and that the amount of force -of which this consumption of heat would be the equivalent -corresponds to that which would be required to raise a -weight of upwards of one thousand millions of tons to a -height of one mile.<a id="FNanchor_45" href="#Footnote_45" class="fnanchor">45</a> When we remember that the land -surface of the earth amounts to about fifty millions of square -miles, we perceive how enormous must be the force-equivalent -of the annual rainfall of our earth. We are apt to<span class="pagenum"><a id="Page_387">387</a></span> -overlook when contemplating the silent and seemingly quiet -processes of nature—such as the formation of the rain-cloud -or the precipitation of rain—the tremendous energy of the -forces really causing these processes. “I have seen,” says -Professor Tyndall, “the wild stone-avalanches of the Alps, -which smoke and thunder down the declivities with a -vehemence almost sufficient to stun the observer. I have -also seen snow-flakes descending so softly as not to hurt the -fragile spangles of which they were composed; yet to produce -from aqueous vapour a quantity which a child could -carry of that tender material demands an exertion of energy -competent to gather up the shattered blocks of the largest -stone-avalanche I have ever seen, and pitch them to twice -the height from which they fell.”</p> - -<hr /> - -<p><span class="pagenum"><a id="Page_388">388</a></span></p> - -<div class="chapter"> -<h2><a id="ANCIENT_BABYLONIAN_ASTROGONY"></a><i>ANCIENT BABYLONIAN ASTROGONY.</i></h2> -</div> - -<p class="in0">It is singular to consider how short a time elapsed, after -writings in the arrow-headed or cuneiform letters (the Keilschriften -of the Germans) were discovered, before, first, the -power of interpreting them was obtained, and, secondly, the -range of the cuneiform literature (so to speak) was recognized. -Not more than ninety years have passed since the first specimens -of arrow-headed inscriptions reached Europe. They -had been known for a considerable time before this. -Indeed, it has been supposed that the Assyrian letters -referred to by Herodotus, Thucydides, and Pliny, were in this -character. Della Valle and Figueroa, early in the seventeenth -century, described inscriptions in arrow-headed letters, -and hazarded the idea that they are to be read from left to -right. But no very satisfactory evidence was advanced to -show whether the inscriptions were to be so read, or from -right to left, or, as Chardin suggested, in vertical lines. The -celebrated Olaus Gerhard Tychsen, of Rostock, and other -German philologists, endeavoured to decipher the specimens -which reached Europe towards the end of the last century; -but their efforts, though ingenious and zealous, were not -rewarded with success. In 1801 Dr. Hager advanced the -suggestion that the combinations formed by the arrow-heads -did not represent letters but words, if not entire sentences. -Lichtenstein, on the other hand, maintained that the letters -belonged to an old form of the Arabic or Coptic character;<span class="pagenum"><a id="Page_389">389</a></span> -and he succeeded to his own satisfaction in finding various -passages from the Koran in the cuneiform inscriptions. Dr. -Grotefend was the first to achieve any real success in this -line of research. It is said that he was led to take up the -subject by a slight dispute with one of his friends, which led -to a wager that he would decipher one of the cuneiform -inscriptions. The results of his investigations were that -cuneiform inscriptions are alphabetical, not hieroglyphical; -that the language employed is the basis of most of the -Eastern languages; and that it is written from right to left. -Since his time, through the labours of Rich, Botta, Rawlinson, -Hincks, De Saulcy, Layard, Sayce, George Smith, and -others, the collection and interpretation of the arrow-headed -inscriptions have been carried out with great success. We -find reason to believe that, though the original literature of -Babylon was lost, the tablet libraries of Assyria contained -copies of most of the writings of the more ancient nation. -Amongst these have been found the now celebrated descriptions -of the Creation, the Fall of Man, the Deluge, the Tower -of Babel, and other matters found in an abridged and -expurgated form in the book of Genesis. It is to that -portion of the Babylonian account which relates to the -creation of the sun and moon and stars that I wish here to -call attention. It is not only curious in itself, but throws -light, in my opinion, on questions of considerable interest -connected with the views of ancient Eastern nations respecting -the heavenly bodies.</p> - -<p>It may be well, before considering the passage in question, -to consider briefly—though we may not be able definitely -to determine—the real antiquity of the Babylonian -account.</p> - -<p>In Smith’s interesting work on the Chaldæan account of -Genesis, the question whether the Babylonian account preceded -the writing of the book of Genesis, or <i xml:lang="la" lang="la">vice versâ</i>, is -not definitely dealt with. Probably this part of his subject -was included among the “important comparisons and conclusions -with respect to Genesis” which he preferred to<span class="pagenum"><a id="Page_390">390</a></span> -avoid, as his “desire was first to obtain the recognition of the -evidence without prejudice.” It might certainly have interfered -to some degree with the unprejudiced recognition of -the evidence of the tablets if it had been maintained by him, -and still more if he had demonstrated, that the Babylonian -is the earlier version. For the account in the book of -Genesis, coming thus to be regarded as merely an expurgated -version of a narrative originally containing much fabulous -matter, and not a little that is monstrous and preposterous, -would certainly not have been presented to us in quite that -aspect in which it had long been regarded by theologians.</p> - -<p>But although Mr. Smith states that he placed the various -dates as low as he fairly could, considering the evidence,—nay, -that he “aimed to do this rather than to establish any -system of chronology,”—there can be no mistake about the -relative antiquity which he in reality assigns to the Babylonian -inscriptions. He states, indeed, that every copy of the -Genesis legends belongs to the reign of Assurbanipal, who -reigned over Assyria <span class="smcap smaller">B.C.</span> 670. But it is “acknowledged on -all hands that the tablets are not the originals, but are only -copies from earlier texts.” The Assyrians acknowledge -themselves that this literature was borrowed from Babylonian -sources, and of course it is to Babylonia we have to look to -ascertain the approximate dates of the original documents. -“The difficulty,” he proceeds, “is increased by the following -considerations: it appears that at an early period in Babylonian -history a great literary development took place, and -numerous works were produced which embodied the prevailing -myths, religion, and science of that day. Written, -many of them, in a noble style of poetry on one side, or -registering the highest efforts of their science on the other, -these texts became the standards for Babylonian literature, -and later generations were content to copy these writings -instead of making new works for themselves. Clay, the -material on which they were written, was everywhere -abundant, copies were multiplied, and by the veneration in -which they were held these texts fixed and stereotyped the<span class="pagenum"><a id="Page_391">391</a></span> -style of Babylonian literature, and the language in which -they were written remained the classical style in the country -down to the Persian conquest. Thus it happens that texts -of Rim-agu, Sargon, and Hammurabi, who were 1000 years -before Nebuchadnezzar and Nabonidus, show the same -language as the texts of these later kings, there being no -sensible difference in style to match the long interval -between them,”—precisely as a certain devotional style of -writing of our own day closely resembles the style of the -sixteenth century.</p> - -<p>We cannot, then, from the style, determine the age of the -original writings from which the Assyrian tablets were copied. -But there are certain facts which enable us to form an opinion -on this point. Babylonia was conquered about <span class="smcap smaller">B.C.</span> 1300, -by Tugultininip, king of Assyria. For 250 years before that -date a foreign race (called by Berosus, Arabs) had ruled in -Babylonia. There is no evidence of any of the original -Babylonian Genesis tablets being written after the date of -Hammurabi, under whom it is supposed that this race -obtained dominion in Babylonia. Many scholars, indeed, -regard Hammurabi as much more ancient; but none set -him later than 1550 <span class="smcap smaller">B.C.</span></p> - -<p>Now, before the time of Hammurabi several races of -kings reigned, their reigns ranging over a period of 500 -years. They were called chiefly Kings of Sumir and Akkad—that -is, Kings of Upper and Lower Babylonia. It is believed -that before this period,—ranging, say, from about -2000 <span class="smcap smaller">B.C.</span> to 1550 <span class="smcap smaller">B.C.</span> (at least not later, though possibly, and -according to many scholars, probably, far earlier),—the two -divisions of Babylonia were separate monarchies. Thus, -evidence whether any literature was written before or after -<span class="smcap smaller">B.C.</span> 2000, may be found in the presence or absence of -mention, or traces, of this division of the Babylonian kingdom. -Mr. Smith considers, for example, that two works,—the -great Chaldæan work on astrology, and a legend which -he calls “The Exploits of Lubara,”—certainly belong to the -period preceding <span class="smcap smaller">B.C.</span> 2000. In the former work, the subject<span class="pagenum"><a id="Page_392">392</a></span> -of which specially connects it, as will presently be seen, -with the tablet relating to the creation of the heavenly -bodies, Akkad is always referred to as a separate state.</p> - -<p>Now Mr. Smith finds that the story of the Creation and -Fall belongs to the upper or Akkad division of the country. -The Izdubar legends, containing the story of the Flood, and -what Mr. Smith regards as probably the history of Nimrod, -seem to belong to Sumir, the southern division of Babylonia. -He considers the Izdubar legends to have been written at -least as early as <span class="smcap smaller">B.C.</span> 2000. The story of the Creation “may -not have been committed to writing so early;” but it also is -of great antiquity. And these legends “were traditions -before they were committed to writing, and were common, -in some form, to all the country.” Remembering Mr. -Smith’s expressed intention of setting all dates as late as -possible, his endeavour to do this rather than to establish -any system of chronology, we cannot misunderstand the real -drift of his arguments, or the real significance of his conclusion -that the period when the Genesis tablets were -originally written extended from <span class="smcap smaller">B.C.</span> 2000 to <span class="smcap smaller">B.C.</span> 1550, or -roughly synchronized with the period from Abraham to -Moses, according to the ordinary chronology of our Bibles. -“During this period it appears that traditions of the creation -of the universe, and human history down to the time of -Nimrod, existed parallel to, and in some points identical -with, those given in the book of Genesis.”</p> - -<p>Thus viewing the matter, we recognize the interest of -that passage in the Babylonian Genesis tablets which corresponds -with the account in the book of Genesis respecting the -creation of the heavenly bodies. We find in it the earliest -existent record of the origin of astrological superstitions. It -does not express merely the vague belief, which might be -variously interpreted, that the sun and moon and stars were -specially created (after light had been created, after the firmament -had been formed separating the waters above from -the waters below, and after the land had been separated -from the water) to be for signs and for seasons for the inhabitants<span class="pagenum"><a id="Page_393">393</a></span> -of the world—that is, of our earth. It definitely -states that those other suns, the stars, were set into constellation -figures for man’s benefit; the planets and the moon -next formed for his use; and the sun set thereafter in the -heavens as the chief among the celestial bodies.</p> - -<p>It runs thus, so far as the fragments have yet been -gathered together:—</p> - -<p class="p2 center newpage"><span class="smcap">Fifth Tablet of Creation Legend.</span></p> - -<blockquote class="hang2"> - -<p> 1. It was delightful all that was fixed by the great gods.</p> - -<p> 2. Stars, their appearance [in figures] of animals he arranged,</p> - -<p> 3. To fix the year through the observation of their constellations,</p> - -<p> 4. Twelve months (or signs) of stars in three rows he arranged,</p> - -<p> 5. From the day when the year commences unto the close.</p> - -<p> 6. He marked the positions of the wandering stars (planets) to shine -in their courses,</p> - -<p> 7. That they may not do injury, and may not trouble any one.</p> - -<p> 8. The positions of the gods Bel and Hea he fixed with him.</p> - -<p> 9. And he opened the great gates in the darkness shrouded,</p> - -<p>10. The fastenings were strong on the left and right.</p> - -<p>11. In its mass (<i>i.e.</i> the lower chaos) he made a boiling.</p> - -<p>12. The god Uru (the moon) he caused to rise out, the night he over -shadowed,</p> - -<p>13. To fix it also for the light of the night until the shining of the day,</p> - -<p>14. That the month might not be broken, and in its amount be regular.</p> - -<p>15. At the beginning of the month, at the rising of the night,</p> - -<p>16. His horns are breaking through to shine on the heaven.</p> - -<p>17. On the seventh day to a circle he begins to swell,</p> - -<p>18. And stretches towards the dawn further.</p> - -<p>19. When the god Shamas (the sun) in the horizon of heaven, in the -east,</p> - -<p>20. . . . formed beautifully and . . .</p> - -<p>21. . . . . . . to the orbit Shamas was perfected</p> - -<p>22. . . . . . . . . . the dawn Shamas should change</p> - -<p>23. . . . . . . . . . . . . going on its path</p> - -<p>24. . . . . . . . . . . . . . . . giving judgment</p> - -<p>25. . . . . . . . . . . . . . . . . . . to tame</p> - -<p>26. . . . . . . . . . . . . . . . . . . . . . a second time</p> - -<p>27. . . .</p></blockquote> - -<p>Of this tablet Smith remarks that it is a typical specimen -of the style of the series, and shows a marked stage in the<span class="pagenum"><a id="Page_394">394</a></span> -Creation, the appointment of the heavenly orbs running -parallel to the biblical account of the fourth day of Creation. -It is important to notice its significance in this respect. -We can understand now the meaning underlying the words, -“God said, Let there be lights in the firmament of the -heavens, to divide the day from the night; and let them be -for signs and for seasons, and for days and years.” The -order, indeed, in which the bodies are formed according to -the biblical account is inverted. The greater light—the -sun—is made first, to rule the day: then the lesser light—the -moon—to rule the night. These are the heavenly -bodies which in this description rule the day of 24 hours. -The sun may be regarded also as ruling (according to the -ancient view, as according to nature) the seasons and the -year. The stars remain as set in the heaven for signs. -“He made the stars also.” “And God set them”—that is, -the sun, moon, and stars—“in the firmament of the heaven -to give light upon the earth, and to rule over the day and -over the night,” and so forth.</p> - -<p>No one can doubt, I conceive, that the biblical account -is superior to the other, both in a scientific and in a literary -sense. It states much less as actually known, and what it -does state accords better with the facts known in the writer’s -day. Then, the Babylonian narrative, though impressive in -certain passages, is overloaded with detail. In both accounts -we find the heavenly bodies set in the firmament by a -special creative act, and specially designed for the benefit -of man. And in passing I would observe that the discovery -of these Babylonian inscriptions, however they may be -interpreted, and whether they be regarded as somewhat -earlier or somewhat later than the Bible narrative, appears -to dispose finally of the fantastic interpretation assigned by -Hugh Miller and others to the biblical cosmogony, as -corresponding to a series of visions in which the varying -aspects of the world were presented. It has long seemed -to me an utterly untenable proposition that a narrative -seemingly intended to describe definitely a certain series of<span class="pagenum"><a id="Page_395">395</a></span> -events should, after being for ages so interpreted, require now -for its correct interpretation to be regarded as an account of -a series of visions. If the explanation were reconcilable in -any way with the words of Genesis, there yet seems something -of profanity in imagining that men’s minds had thus -been played with by a narrative purporting to be of one -sort yet in reality of quite a different character. But whatever -possibility there may be (and it can be but the barest -possibility) that the Genesis narrative admits of the vision -interpretation, no one can reasonably attempt to extend -that interpretation to the Babylonian account. So that -either a narrative from which the Genesis account was presumably -derived was certainly intended to describe a series -of events, or else a narrative very nearly as early as the -Genesis account, and presumably derived from it at a time -when its true meaning must have been known, presents the -sun, moon, and stars as objects expressly created and set -in the sky after the earth had been formed, and for the -special benefit of man as yet uncreated.</p> - -<p>I am not concerned, however, either to dwell upon this -point, or to insist on any of its consequences. Let us return -to the consideration of the Babylonian narrative as it stands.</p> - -<p>We find twelve constellations or signs of the zodiac are -mentioned as set to fix the year. I am inclined to consider -that the preceding words, “stars, their appearance in figures -of animals he arranged,” relate specially to the stars of the -zodiac. The inventor of this astrogony probably regarded -the stars as originally scattered in an irregular manner over -the heavens,—rather as chaotic material from which constellations -might be formed, than as objects separately and -expressly created. Then they were taken and formed into -figures of animals, set in such a way as to fix the year -through the observation of these constellations. It is hardly -necessary, perhaps, to remind the reader that the word -zodiac is derived from a Greek word signifying an animal, -the original name of the zone being the zodiacal way, or -the pathway of the animals. Our older navigators called it<span class="pagenum"><a id="Page_396">396</a></span> -the Bestiary.<a id="FNanchor_46" href="#Footnote_46" class="fnanchor">46</a> “Twelve months or signs in three rows.” -Smith takes the three rows to mean (i.) the zodiacal signs, -(ii.) the constellations north of the zodiac, and (iii.) the -constellations south of the zodiac. But this does not agree -with the words “twelve signs in three rows.” Possibly the -reference is to three circles, two bounding the zodiac on the -north and south respectively, the third central, the ecliptic, -or track of the sun; or the two tropics and the equator may -have been signified. Instead of “twelve signs in three rows,” -we should, probably, read “twelve signs along a triple band.” -The description was written long after astronomical temples -were first erected, and as the designer of a zodiacal dome -like that (far more recently) erected at Denderah would set -the twelve zodiacal signs along a band formed by three -parallel circles, marking its central line and its northern and -southern limits, so we can understand the writer of the -tablet presenting the celestial architect as working in the -same lines, on a grander scale; setting the twelve zodiacal -signs on the corresponding triple band in the heavens themselves.</p> - -<p>The next point to be noticed in the Babylonian astrology<span class="pagenum"><a id="Page_397">397</a></span> -is the reference to “wandering stars.” Mr. Smith remarks -that the word <i>nibir</i>, thus translated, “is not the usual word -for planet, and there is a star called <i>Nibir</i> near the place -where the sun crossed the boundary between the old and -new years, and this star was one of twelve supposed to -be favourable to Babylonia.” “It is evident,” he proceeds, -“from the opening of the inscription on the first tablet of -the Chaldæan astrology and astronomy, that the functions -of the stars were, according to the Babylonians, to act not -only as regulators of the seasons and the year, but also to -be used as signs, as in Genesis i. 14; for in those ages it -was generally believed that the heavenly bodies gave, by -their appearance and positions, signs of events which were -coming on the earth.” The two verses relating to Nibir -seem to correspond to no other celestial bodies but planets -(unless, perhaps, to comets). If we regard Nibir as signifying -any fixed star, we can find no significance in the marking -of the course of the star Nibir, that it may do no injury -and may not trouble any one. Moreover, as the fixed stars, -the sun, and the moon, are separately described, it seems -unlikely that the planets would be left unnoticed. In the -biblical narrative the reference to the celestial bodies is so -short that we can understand the planets being included in -the words, “He made the stars also.” But in an account -so full of detail as that presented in the Babylonian tablet, -the omission of the planets would be very remarkable. It -is also worthy of notice that in Polyhistor’s Babylonian -traditions, recorded by Berosus, we read that “Belus formed -the stars, the sun, the moon, and the five planets.”</p> - -<p>In the tablet narrative the creator of the heavenly bodies -is supposed to be Anu, god of the heavens. This is inferred -by Mr. Smith from the fact “that the God who created the -stars, fixed places or habitations for Bel and Hea with himself -in the heavens.” For according to the Babylonian -theogony, the three gods Anu, Bel, and Hea share between -them the divisions of the face of the sky.</p> - -<p>The account of the creation of the moon is perhaps the<span class="pagenum"><a id="Page_398">398</a></span> -most interesting part of the narrative. We see that, according -to the Babylonian philosophy, the earth is regarded as -formed from the waters and resting after its creation above -a vast abyss of chaotic water. We find traces of this old -hypothesis in several biblical passages, as, for instance, in -the words of the Third Commandment, “the heaven above, -the earth beneath, and the waters under the earth;” and -again in Proverbs xxx. 4, “Who hath bound the waters in -a garment? who hath established all the ends of the earth?” -“The great gates in the darkness shrouded, the fastenings -strong on the left and right,” in the Babylonian account, -refer to the enclosure of the great infernal lake, so that the -waters under the earth might not overwhelm the world. It -is from out the dark ocean beneath the earth that the god -Anu calls the moon into being. He opens the mighty gates -shrouded in the nether darkness, and creates a vast whirlpool -in the gloomy ocean; then “at his bidding, from the -turmoil arose the moon like a giant bubble, and passing -through the open gates mounted on its destined way across -the vaults of heaven.” It is strange to reflect that in quite -recent times, at least 4000 years after the Babylonian tablet -was written, and who shall tell how many years after the -tradition was first invented?—a theory of the moon’s origin -not unlike the Babylonian hypothesis has been advanced, -despite overwhelming dynamical objections; and a modern -paradoxist has even pointed to the spot beneath the ocean -where a sudden increase of depth indicates that matter was -suddenly extruded long ago, and driven forcibly away from -the earth to the orbit along which that expelled mass—our -moon—is now travelling.</p> - -<p>It would have been interesting to have known how the -Babylonian tablet described the creation of Shamas, the -sun; though, so far as can be judged from the fragments -above quoted, there was not the same fulness of detail in -this part of the description as in that relating to the moon. -Mr. Smith infers that the Babylonians considered the moon -the more important body, unlike the writer or compiler of<span class="pagenum"><a id="Page_399">399</a></span> -the book of Genesis, who describes the sun as the greater -light. It does not seem to follow very clearly, however, -from the tablet record, that the sun was considered inferior -to the moon in importance, and certainly we cannot imagine -that the Babylonians considered the moon a greater light. -The creation of the stars precedes that of the moon, though -manifestly the moon was judged to be more important than -the stars. Not improbably, therefore, the sun, though -following the moon in order of creation, was regarded as -the more important orb of the two. In fact, in the Babylonian -as in the (so-called) Mosaic legend of Creation, the -more important members of a series of created bodies are, -in some cases, created last—man last of all orders of animated -beings, for instance.</p> - -<p>If we turn now from the consideration of the Babylonian -tradition of the creation of the heavenly bodies to note how -the biblical account differs from it, not only or chiefly in -details, but in general character, we seem to recognize in -the latter a determination to detach from the celestial orbs -the individuality, so to speak, which the older tradition had -given to them. The account in Genesis is not only simpler, -and, in a literary sense, more effective, but it is in another -sense purified. The celestial bodies do not appear in it as -celestial beings. The Babylonian legend is followed only so -far as it can be followed consistently with the avoidance of -all that might tempt to the worship of the sun, moon, and -stars. The writer of the book of Genesis, whether Moses -or not, seems certainly to have shared the views of Moses as -to the Sabæanism of the nation from which the children of -Abraham had separated. Moses warned the Israelite,—“Take -good heed unto thyself, lest thou lift up thine eyes -unto heaven; and when thou seest the sun, and the moon, -and the stars, even all the host of heaven, shouldest be -driven to worship them, and serve them, which the Lord thy -God hath divided unto all nations under the whole heaven.” -So the writer of Genesis is careful to remove from the tradition -which he follows all that might suggest the individual<span class="pagenum"><a id="Page_400">400</a></span> -power and influence of the heavenly bodies. The stars are -to be for signs, but we read nothing of the power of the -wandering stars “to do injury or trouble any one.” (That is, -not in the book of Genesis. In the song of Deborah we -find, though perhaps only in a poetic fashion, the old influences -assigned to the planets, when the singer says that -the “stars in their courses fought against Sisera.” Deborah, -however, was a woman, and women have always been loth -and late to give up ancient superstitions.) Again, the sun -and the moon in Genesis are the greater and the lesser -lights, not, as in the Babylonian narrative, the god Shamas -and the god Uru.</p> - -<p>We may find a parallel to this treatment of the Babylonian -myth in the treatment by Moses of the observance of -the Sabbath, a day of rest which the Babylonian tablets show -to have had, as for other reasons had been before suspected, -an astrological significance. The Jewish lawgiver does not -do away with the observance; in fact, he was probably -powerless to do away with it. At any rate, he suffers the -observance to remain, precisely as the writer of the book of -Genesis retains the Babylonian tradition of the creation of -the celestial bodies. But he is careful to expurgate the -Chaldæan observance, just as the writer of Genesis is careful -to expurgate the Babylonian tradition. The week as a -period is no longer associated with astrological superstitions, -nor the Sabbath rest enjoined as a fetish. Both ideas are -directly associated with the monotheistic principle which -primarily led to the separation of the family of Abraham -from the rest of the Chaldæan race. In Babylonia, the -method of associating the names of the sun, moon, and stars -with the days, doubtless had its origin. Saturn was the -Sabbath star, as it is still called (Sabbatai) in the Talmud. -But, as Professor Tischendorf told Humboldt, in answer to -a question specially addressed to him on the subject, “there -is an entire absence in both the Old and New Testaments, -of any traces of names of week-days taken from the planets.” -The lunar festivals, again, though unquestionably Sabaistic<span class="pagenum"><a id="Page_401">401</a></span> -in their origin, were apparently too thoroughly established -to be discarded by Moses; nay, he was even obliged to -permit the continuance of many observances which suspiciously -resembled the old offerings of sacrifice to the moon as -a deity. He had also to continue the sacrifice of the passover, -the origin of which was unmistakably astronomical,—corresponding -in time to the sun’s passage across the -equator, or rather to the first lunar month following and -including that event. But he carefully dissociates both the -lunar and the lunisolar sacrifices from their primary Sabaistic -significance. In fact, the history of early Hebrew legislation, -so far as it related to religion, is the history of a struggle -on the part of the lawgivers and the leaders of opinion against -the tendency of the people to revert to the idolatrous worship -of their ancestors and of races closely akin to them—especially -against the tendency to the worship of the sun and moon -and all the host of heaven.</p> - -<p>In the very fact, however, that this contest was maintained, -while yet the Hebrew cosmogony, and in particular -the Hebrew astrogony, contains indubitable evidence of its -origin in the poetical myths of older Babylonia, we find one -of the strongest proofs of the influence which the literature -of Babylon, when at the fulness of its development, exerted -upon surrounding nations. This influence is not more -clearly shown even by the fact that nearly 2000 years after -the decay of Babylonian literature, science, and art, a nation -like the Assyrians, engaged in establishing empire rather -than in literary and scientific pursuits, should have been at -the pains to obtain copies of many thousands of the tablet -records which formed the libraries of older Babylonia. In -both circumstances we find good reason for hoping that -careful search among Assyrian and Babylonian ruins may -not only be rewarded by the discovery of many other portions -of the later Assyrian library (which was also in some sense a -museum), but that other and earlier copies of the original -Babylonian records may be obtained. For it seems unlikely -that works so valuable as to be thought worth recopying after<span class="pagenum"><a id="Page_402">402</a></span> -1500 or 2000 years, in Assyria, had not been more than -once copied during the interval in Babylonia. “Search in -Babylonia,” says Mr. Smith, “would no doubt yield earlier -copies of all these works, but that search has not yet been -instituted, and for the present we have to be contented with -our Assyrian copies. Looking, however, at the world-wide -interest of the subjects, and at the important evidence which -perfect copies of these works would undoubtedly give, there -can be no doubt,” Mr. Smith adds, “that the subject of -further search and discovery will not slumber, and that all as -yet known will one day be superseded by newer texts and -fuller and more perfect light.”</p> - -<p class="p4 center smaller vspace"> -Printed by <span class="smcap">Ballantyne, Hanson & Co.</span><br /> -Edinburgh & London -</p> - -<div class="chapter"><div class="footnotes"> -<h2 class="nobreak p1"><a id="FOOTNOTES"></a>FOOTNOTES</h2> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_1" href="#FNanchor_1" class="fnanchor">1</a> More strictly, it plays the same part as a glass screen before a -glowing fire. When the heat of the fire falls on such a screen (through -which light passes readily enough), it is received by the glass, warming -the glass up to a certain point, and the warmed glass emits in all directions -the heat so received; thus scattering over a large space the rays -which, but for the glass, would have fallen directly upon the objects -which the screen is intended to protect.</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_2" href="#FNanchor_2" class="fnanchor">2</a> The case here imagined is not entirely hypothetical. We examine -Mercury and Venus very nearly under the conditions here imagined; -for we can obtain only spectroscopic evidence respecting the existence of -water on either planet. In the case of Mars we have telescopic evidence, -and no one now doubts that the greenish parts of the planet are seas -and oceans. But Venus and Mercury are never seen under conditions -enabling the observer to determine the colour of various parts of their -discs. -</p> -<p> -I may add that a mistake, somewhat analogous to that which I have -described in the cases of an imagined observer of our earth, has been -made by some spectroscopists in the case of the planets Jupiter and -Saturn. In considering the spectroscopic evidence respecting the condition -of these planets’ atmospheres, they have overlooked the circumstance -that we can judge only of the condition of the outermost and -coolest layers, for the lower layers are concealed from view by the -enormous cloud masses, floating, as the telescope shows, in the atmospheric -envelopes of the giant planets. Thus the German spectroscopist -Vögel argues that because in the spectrum of Jupiter dark lines are seen -which are known to belong to the absorption-spectrum of aqueous -vapour, the planet’s surface cannot be intensely hot. But Jupiter’s -absorption-spectrum belongs to layers of his atmosphere lying far above -his surface. We can no more infer the actual temperature of Jupiter’s -surface from the temperature of the layers which produce his absorption-spectrum, -than a visitor who should view our earth from outer space, -observing the low temperature of the air ten or twelve miles above the -sea-level, could infer thence the actual temperature of the earth’s surface.</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_3" href="#FNanchor_3" class="fnanchor">3</a> In “Other Worlds than Ours,” I wrote as follows:—“The lines -of hydrogen, which are so well marked in the solar spectrum, are not -seen in the spectrum of Betelgeux. We are not to conclude from this -that hydrogen does not exist in the composition of the star. We know -that certain parts of the solar disc, when examined with the spectroscope, -do not at all times exhibit the hydrogen lines, or may even present them -as bright instead of dark lines. It may well be that in Betelgeux -hydrogen exists under such conditions that the amount of light it sends -forth is nearly equivalent to the amount it absorbs, in which case its -characteristic lines would not be easily discernible. In fact, it is important -to notice generally, that while there can be no mistaking the -positive evidence afforded by the spectroscope as to the existence of -any element in sun or star, the negative evidence supplied by the absence -of particular lines is not to be certainly relied upon.”</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_4" href="#FNanchor_4" class="fnanchor">4</a> Dr. Draper remarks here in passing, “I do not think that, in -comparisons of the spectra of the elements and sun, enough stress has -been laid on the general appearance of lines apart from their mere -position; in photographic representations this point is very prominent.”</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_5" href="#FNanchor_5" class="fnanchor">5</a> The word “ignited” may mislead, and indeed is not correctly -used here. The oxygen in the solar atmosphere, like the hydrogen, is -simply glowing with intensity of heat. No process of combustion is -taking place. Ignition, strictly speaking, means the initiation of the -process of combustion, and a substance can only be said to be ignited -when it has been set burning. The word <em>glowing</em> is preferable; or if -reference is made to heat and light combined, then “glowing with intensity -of heat” seems the description most likely to be correctly understood.</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_6" href="#FNanchor_6" class="fnanchor">6</a> It would be an interesting experiment, which I would specially -recommend to those who, like Dr. Draper, possess instrumental means -specially adapted to the inquiry, to ascertain what variations, if any, -occur in the solar spectrum when (i.) the central part of the disc alone, -and (ii.) the outer part alone, is allowed to transmit light to the spectroscope. -The inquiry seems specially suited to the methods of spectral -photography pursued by Dr. Draper, and by Dr. Huggins, in this -country. Still, I believe interesting results can be obtained even without -these special appliances; and I hope before long to employ my own -telescope in this department of research.</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_7" href="#FNanchor_7" class="fnanchor">7</a> In 1860, a year of maximum sun-spot frequency, Cambridge won -the University boat-race; the year 1865, of minimum sun-spot frequency, -marked the middle of a long array of Oxford victories; 1872, the next -maximum, marked the middle of a Cambridge series of victories. May -we not anticipate that in 1878, the year of minimum spot frequency, -Oxford will win? [This prediction made in autumn, 1877, was fulfilled.] -I doubt not similar evidence might be obtained about cricket.</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_8" href="#FNanchor_8" class="fnanchor">8</a> It must be understood that this remark relates only to the theory -that by close scrutiny of the sun a power of predicting weather peculiarities -can be obtained, not to the theory that there may be a cyclic -association between sun-spots and the weather. If this association -exists, yet no scrutiny of the sun can tell us more than we already know, -and it will scarcely be pretended that new solar observatories could -give us any better general idea of the progress of the great sun-spot -period than we obtain from observatories already in existence, or, -indeed, might obtain from the observations of a single amateur telescopist. -</p> -<p> -I think it quite possible that, from the systematic study of terrestrial -relations, the existence of a cyclic association between the great spot -period and terrestrial phenomena may be demonstrated, instead of being -merely surmised, as at present. By the way, it may be worth noting -that a prediction relative to the coming winter [that of 1877–78] has -been made on the faith of such association by Professor Piazzi Smyth. -It runs as follows:— -</p> -<p> -“Having recently computed the remaining observations of our -earth-thermometers here, and prepared a new projection of all the observations -from their beginning in 1837 to their calamitous close last -year [1876]—results generally confirmatory of those arrived at in 1870 -have been obtained, but with more pointed and immediate bearing on -the weather now before us. -</p> -<p> -“The chief features undoubtedly deducible for the past thirty-nine -years, after eliminating the more seasonal effects of ordinary summer -and winter, are:— -</p> -<p> -“1. Between 1837 and 1876 three great heat-waves, from without, -struck this part of the earth, viz., the first in 1846·5, the second in -1858·0, and the third in 1868·7. And unless some very complete alteration -in the weather is to take place, the next such visitation may be -looked for in 1879·5, within limits of half a year each way. -</p> -<p> -“2. The next feature in magnitude and certainty is that the periods -of minimum temperature, or cold, are not either in, or anywhere near, -the middle time between the crests of those three chronologically -identified heat-waves, but are comparatively close up to them <em>on either -side</em>, at a distance of about a year and a half, so that the next such cold-wave -is due at the end of the present year [1877]. -</p> -<p> -“This is, perhaps, not an agreeable prospect, especially if political -agitators are at this time moving amongst the colliers, striving to persuade -them to decrease the out-put of coal at every pit’s mouth. Being, -therefore, quite willing, for the general good, to suppose myself mistaken, -I beg to send you a first impression of plate 17 of the forthcoming -volume of observations of this Royal Observatory, and shall be -very happy if you can bring out from the measures recorded there any -more comfortable view for the public at large. -</p> -<p class="sigright"> -<span class="l4">“<span class="smcap">Piazzi Smyth</span>,</span><br /> -“Astronomer-Royal for Scotland.” -</p> -<p> -If this prediction shall be confirmed [this was written in autumn, -1877], it will afford an argument in favour of the existence of the cyclic -relation suggested, but no argument for the endowment of solar research. -Professor Smyth’s observations were not solar but terrestrial. -</p> -<p> -[The prediction was not confirmed, the winter of 1877–78 being, on -the contrary, exceptionally mild.]</p></div> - -<div class="footnote"> - -<p class="fn1"><a id="Footnote_9" href="#FNanchor_9" class="fnanchor">9</a> The reader unfamiliar with the principles of the telescope may -require to be told that in the ordinary telescope each part of the object-glass -forms a complete image of the object examined. If, when using -an opera-glass (one barrel), a portion of the large glass be covered, a -portion of what had before been visible is concealed. But this is not -the case with a telescope of the ordinary construction. All that happens -when a portion of the object-glass is covered is that the object appears -in some degree less fully illuminated.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_10" href="#FNanchor_10" class="fnanchor">10</a> It may be briefly sketched, perhaps, in a note. The force necessary -to draw the earth inwards in such sort as to make her follow her -actual course is proportional to (i) the square of her velocity directly, -and (ii) her distance from the sun inversely. If we increase our estimate -of the earth’s distance from the sun, we, in the same degree, -increase our estimate of her orbital velocity. The square of this velocity -then increases as the square of the estimated distance; and therefore, -the estimated force sunwards is increased as the square of the distance -on account of (i), and diminished as the distance on account of (ii), and -is, therefore, on the whole, increased as the distance. That is, we now -regard the sun’s action as greater at this greater distance, and in the -same degree that the distance is greater; whereas, if it had been what -we before supposed it, it would be less at the greater distance as the -square of the distance (attraction varying inversely as the square of the -distance). Being greater as the distance, instead of less as the square -of the distance, it follows that our estimate of the sun’s absolute force is -now greater as the cube of the distance. Similarly, if we had diminished -our estimate of the sun’s distance, we should have diminished our estimate -of his absolute power (or mass) as the cube of the distance. But -our estimate of the sun’s volume is also proportional to the cube of his -estimated distance. Hence our estimate of his mass varies as our -estimate of his volume; or, our estimate of his mean density is constant.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_11" href="#FNanchor_11" class="fnanchor">11</a> Only very recently an asteroid, Hilda (153rd in order of detection), -has been discovered which travels very much nearer to the path of -Jupiter than to that of Mars—a solitary instance in that respect. Its -distance (the earth’s distance being represented by unity), is 3·95, -Jupiter’s being 5·20, and Mars’s 1·52; its period falls short of 8 years -by only two months, the average period of the asteroidal family being -only about 4½ years. Five others, Cybele, Freia, Sylvia, Camilla, and -Hermione, travel rather nearer to Jupiter than to Mars; but the remaining -166 travel nearer to Mars, and most of them much nearer.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_12" href="#FNanchor_12" class="fnanchor">12</a> Even this statement is not mathematically exact. If the rails are -straight and parallel, the ratio of approach and recession of an engine -on one line, towards or from an engine on the other, is never quite -equal to the engines’ velocities added together; but the difference -amounts practically to nothing, except when the engines are near each -other.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_13" href="#FNanchor_13" class="fnanchor">13</a> I have omitted all reference to details; but in reality the double -battery was automatic, the motion of the observing telescope, as -different colours of the spectrum were brought into view, setting all the -prisms of the double battery into that precise position which causes them -to show best each particular part of the spectrum thus brought into -view. It is rather singular that the first view I ever had of the solar -prominences, was obtained (at Dr. Huggins’s observatory) with this -instrument of my own invention, which also was the first powerful -spectroscope I had ever used or even seen.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_14" href="#FNanchor_14" class="fnanchor">14</a> It varies more in some months than in others, as the moon’s orbit -changes in shape under the various perturbing influences to which she is -subject.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_15" href="#FNanchor_15" class="fnanchor">15</a> It may seem strange to say that one hundred and twenty years after -the passage of a comet which last passed in 1862, and was then first -discovered, August meteors have been seen. But in reality, as we know -the period of that comet to be about one hundred and thirty years, we -know that the displays of the years 1840, 1841, etc., to 1850, must -have followed the preceding passage by about that interval of time.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_16" href="#FNanchor_16" class="fnanchor">16</a> The D line, properly speaking, as originally named by Fraunhofer, -belongs to sodium. The line spoken of above as the sierra -D line is one close by the sodium line, and mistaken for it when -first seen in the spectrum of the coloured prominences as a bright -line. It does not appear as a dark line in the solar spectrum.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_17" href="#FNanchor_17" class="fnanchor">17</a> Since this was written, I have learned that Mr. Backhouse, of -Sunderland, announced similar results to those obtained at Dunecht, as -seen a fortnight or so earlier.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_18" href="#FNanchor_18" class="fnanchor">18</a> Here no account is taken of the motions of the stars within the -system; such motions must ordinarily be minute compared with the -common motion of the system.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_19" href="#FNanchor_19" class="fnanchor">19</a> Eight pictures of nebulæ were exhibited in illustration of this -peculiarity.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_20" href="#FNanchor_20" class="fnanchor">20</a> Sir John Herschel long since pointed to the variation of our sun as -a possible cause of such changes of terrestrial climate.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_21" href="#FNanchor_21" class="fnanchor">21</a> During these journeys the Atlantic was sounded, and Scoresby’s -estimate of the enormous depth of the Atlantic to the north-west of -Spitzbergen was fully confirmed, the line indicating a depth of more -than two miles. It was found also that Spitzbergen is connected with -Norway by a submarine bank.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_22" href="#FNanchor_22" class="fnanchor">22</a> It is far from improbable that a change has taken place in the -climate of the part of the Arctic regions traversed by Koldewey; for -the Dutch seem readily to have found their way much further north two -centuries ago. Indeed, among Captain Koldewey’s results is one which -seems to indicate the occurrence of such a change. The country he -explored was found to have been inhabited. “Numerous huts of -Esquimaux were seen, and various instruments and utensils of primitive -form; but for some reason or other the region seems to have been finally -deserted. The Polar bear reigns supreme on the glaciers, as the walrus -does among the icebergs.” Not improbably the former inhabitants were -forced to leave this region by the gradually increasing cold.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_23" href="#FNanchor_23" class="fnanchor">23</a> Dr. Emile Bessels was tried at New York in 1872, on the charge -of having poisoned Captain Hall, but was acquitted.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_24" href="#FNanchor_24" class="fnanchor">24</a> The phenomena here described are well worth observing on their -own account, as affording a very instructive and at the same time very -beautiful illustration of wave motions. They can be well seen at many -of our watering-places. The same laws of wave motion can be readily -illustrated also by throwing two stones into a large smooth pool, at -points a few yards apart. The crossing of the two sets of circular waves -produces a wave-net, the meshes of which vary in shape according to their -position.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_25" href="#FNanchor_25" class="fnanchor">25</a> It is a pity that men of science so often forget, when addressing -those who are not men of science, or who study other departments than -theirs, that technical terms are out of place. Most people, I take it -are more familiar, on the whole, with eyelids than with <i xml:lang="la" lang="la">palpebræ</i>.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_26" href="#FNanchor_26" class="fnanchor">26</a> This nautical expression is new to me. Top-gallants—fore, main, -and mizen—I know, and forecastle I know, but the top-gallant forecastle -I do not know.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_27" href="#FNanchor_27" class="fnanchor">27</a> The instrument was lent to Mr. Huggins by Mr. W. Spottiswoode. -It has been recently employed successfully at Greenwich.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_28" href="#FNanchor_28" class="fnanchor">28</a> Thus in <cite>Christie Johnstone</cite>, written in 1853, when Flucker Johnstone -tells Christie the story of the widow’s sorrows, giving it word for -word, and even throwing in what dramatists call “the business,” he -says, “‘Here ye’ll play your hand like a geraffe.’ ‘Geraffe?’ she -says; ‘that’s a beast, I’m thinking.’ ‘Na; it’s the thing on the hill -that makes signals.’ ‘Telegraph, ye fulish goloshen!’ ‘Oo, ay, telegraph! -geraffe’s sunnest said for a’.’” “Playing the hand like a -telegraph” would now be as unmeaning as Flucker Johnstone’s original -description.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_29" href="#FNanchor_29" class="fnanchor">29</a> Not “to represent the gutta-percha,” as stated in the <cite>Times</cite> -account of Mr. Muirhead’s invention. The gutta-percha corresponds -to the insulating material of the artificial circuit; viz., the prepared -paper through which the current along the tinfoil strips acts inductively -on the coating of tinfoil.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_30" href="#FNanchor_30" class="fnanchor">30</a> I must caution the reader against Fig. 348 in Guillemin’s <cite>Application -of the Physical Forces</cite>, in which the part <i>c d</i> of the wire is not shown. -The two coils are in reality part of a single coil, divided into two to -permit of the bar being bent; and to remove the part <i>c d</i> is to divide -the wire, and, of course, break the current. It will be seen that <i>c d</i> -passes from the remote side of coil <i>b c</i>, <a href="#ip_253">Fig. 6</a>, to the near side of coil <i>d e</i>. -If it were taken round the remote side of the latter coil, the current -along this would neutralize the effect of the current along the other.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_31" href="#FNanchor_31" class="fnanchor">31</a> The paper is soaked in dilute ferrocyanide of potassium, and the -passage of the current forms a Prussian blue.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_32" href="#FNanchor_32" class="fnanchor">32</a> Sir W. Thomson states, in his altogether excellent article on the -electric telegraph, in Nichol’s <cite>Cyclopædia</cite>, that the invention of this -process is due to Mr. Bakewell.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_33" href="#FNanchor_33" class="fnanchor">33</a> It is to be noticed, however, that the recording pointer must -always mark its lines in the same direction, so that, unless a message is -being transmitted at the same time that one is being received (in which -case the oscillations both ways are utilized), the instrument works only -during one-half of each complete double oscillation.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_34" href="#FNanchor_34" class="fnanchor">34</a> It seems to me a pity that in the English edition of this work the -usual measures have not been substituted throughout. The book is not -intended or indeed suitable for scientific readers, who alone are accustomed -to the metric system. Other readers do not care to have a little -sum in reduction to go through at each numerical statement.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_35" href="#FNanchor_35" class="fnanchor">35</a> Hanno’s <cite>Periplus</cite>—the voyage of Hanno, chief of the Carthaginians, -round the parts of Libya, beyond the Pillars of Hercules, the -narrative of which he posted up in the Temple of Kronos.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_36" href="#FNanchor_36" class="fnanchor">36</a> I may mention one which occurred within my own experience. -A mastiff of mine, some years ago, was eating from a plate full of broken -meat. It was his custom to bury the large pieces when there was more -than he could get through. While he was burying a large piece, a cat -ran off with a small fragment. The moment he returned to the plate he -missed this, and, seeing no one else near the plate, he, in his own way, -accused a little daughter of mine (some two or three years old) of the -theft. Looking fiercely at her, he growled his suspicions, and would not -suffer her to escape from the corner where his plate stood until I dragged -him away by his chain. Nor did he for some time forget the wrong -which he supposed she had done him, but always growled when she -came near his house.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_37" href="#FNanchor_37" class="fnanchor">37</a> It may be suggested, in passing, that the association which has -been commonly noticed between prominent eyeballs and command of -language (phrenologists place the organ of language, in their unscientific -phraseology, behind the eyeballs) may be related in some degree to the -circumstance that in gradually emerging from the condition of an arboreal -creature the anthropoid ape would not only cease to derive advantage -from sunken eyes, but would be benefited by the possession of more -prominent eyeballs. The increasing prominence of the eyeballs would -thus be a change directly associated with the gradual advance of the -animal to a condition in which, associating into larger and larger companies -and becoming more and more dependent on mutual assistance -and discipline, they would require the use of a gradually extending -series of vocal signs to indicate their wants and wishes to each other.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_38" href="#FNanchor_38" class="fnanchor">38</a> The word hypothesis is too often used as though it were synonymous -with theory, so that Newton’s famous saying, “Hypotheses non -fingo” has come to be regarded by many as though it expressed an -objection on Newton’s part against the formation of theories. This -would have been strange indeed in the author of the noblest theory yet -propounded by man in matters scientific. Newton indicates his meaning -plainly enough, in the very paragraph in which the above expression -occurs, defining an hypothesis as an opinion not based on phenomena.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_39" href="#FNanchor_39" class="fnanchor">39</a> I find it somewhat difficult to understand clearly Mr. Mivart’s -own position with reference to the general theory of evolution. He -certainly is an evolutionist, and as certainly he considers natural selection -combined with the tendency to variation (as ordinarily understood) -insufficient to account for the existence of the various forms of animal -and vegetable existence. He supplies the missing factor in “an innate -law imposed on nature, by which new and definite species, under -definite conditions, emerged from a latent and potential being into -actual and manifest existence;” and, so far as can be judged, he considers -that the origin of man himself is an instance of the operation of -this law.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_40" href="#FNanchor_40" class="fnanchor">40</a> The Middle Tertiary period—the Tertiary, which includes the -Eocene, Miocene, and Pliocene periods, being the latest of the three -great periods recognized by geologists as preceding the present era, -which includes the entire history of man as at present known geologically.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_41" href="#FNanchor_41" class="fnanchor">41</a> Closely following in this respect his illustrious namesake Roger, -who writes, in the sixth chapter of his <cite>Opus Majus</cite>, “<cite>Sine experientia -nihil sufficienter sciri potest.</cite>”</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_42" href="#FNanchor_42" class="fnanchor">42</a> Fibrine and albumen are identical in composition. <em>Caseine</em>, -which is the coagulable portion of milk, is composed in the same manner. -The chief distinction between the three substances consists in -their mode of coagulation; fibrine coagulating spontaneously, albumen -under the action of heat, and caseine by the action of acetic acid.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_43" href="#FNanchor_43" class="fnanchor">43</a> To this article of the Professor’s faith decided objection must be -taken, however.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_44" href="#FNanchor_44" class="fnanchor">44</a> Those whose custom it is to regard all theorizing respecting the -circumstances revealed by observation as unscientific, may read with -profit an extremely speculative passage in Newton’s <cite>Principia</cite> relating -to the probable drying up of the earth in future ages. “As the seas,” -he says, “are absolutely necessary to the constitution of our earth, -that from them the sun, by its heat, may exhale a sufficient quantity of -vapours, which, being gathered together into clouds, may drop down in -rain, for watering of the earth, and for the production and nourishment -of vegetables; or being condensed with cold on the tops of mountains -(as some philosophers with reason judge), may run down in springs -and rivers; so for the conservation of the seas and fluids of the planets, -comets seem to be required, that, from their exhalations and vapours -condensed, the wastes of the planetary fluids spent upon vegetation -and putrefaction, and converted into dry earth, may be ultimately -supplied and made up; for all vegetables entirely derive their growths -from fluids, and afterwards, in great measure, are turned into dry earth -by putrefaction; and a sort of slime is always found to settle at the -bottom of putrefied fluids; and hence it is that the bulk of the solid -earth is continually increased; and the fluids, if they are not supplied -from without, must be in a continual decrease, and quite fail at last. -I suspect, moreover, that it is chiefly from the comets that spirit comes -which is indeed the smallest but the most subtle and useful part of our -air, and so much required to sustain the life of all things with us.”</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_45" href="#FNanchor_45" class="fnanchor">45</a> See my “Science Byways,” pp. 244, 245.</p></div> - -<div class="footnote"> - -<p class="fn2"><a id="Footnote_46" href="#FNanchor_46" class="fnanchor">46</a> The following passage from Admiral Smyth’s Bedford Catalogue -is worth noticing in this connection:—“We find that both the Chinese -and the Japanese had a zodiac consisting of animals, as <em>zodiacs</em> needs -must, among which they placed a tiger, a peacock, a cat, an alligator, -a duck, an ape, a hog, a rat, and what not. Animals also formed the -<i xml:lang="la" lang="la">Via Solis</i> of the Kirghis, the Mongols, the Persians, the Mantshus, and -the ancient Turks; and the Spanish monks in the army of Cortes found -that the Mexicans had a zodiac with strange creatures in the departments. -Such a striking similitude is assuredly indicative of a common -origin, since the coincidences are too exact in most instances to be the -effect of chance; but where this origin is to be fixed has been the -subject of interminable discussions, and learning, ignorance, sagacity, -and prejudice have long been in battle array against each other. -Diodorus Siculus considers it to be Babylonian, but Bishop Warburton, -somewhat dogmatically tells us, ‘Brute worship gave rise to the -Egyptian asterisms prior to the time of Moses.’” There is now, of -course, very little reason for questioning that Egyptian astronomy was -borrowed from Babylon.</p></div> -</div></div> - -<div class="chapter"><div class="transnote"> -<h2 class="nobreak p1"><a id="Transcribers_Notes"></a>Transcriber’s Notes</h2> - -<p>Cover created by Transcriber and placed in the Public Domain.</p> - -<p>Punctuation, hyphenation, and spelling were made consistent when a predominant -preference was found in this book; otherwise they were not changed.</p> - -<p>Simple typographical errors were corrected; occasional unbalanced -quotation marks retained.</p> - -<p>Ambiguous hyphens at the ends of lines were retained.</p> - -<p>Some ditto marks have been replaced by the actual text.</p> - -<p>Page <a href="#ip_83">83</a>: In the illustration, “O” should be “C”.</p> - -<p>Page <a href="#Page_171">171</a>: There is no obvious closing quotation mark to match -the opening mark at “of most unusual age and thickness”.</p> - -<p>Page <a href="#Page_192">192</a>: “Divided even between the ocean” may be a misprint -for “evenly”.</p> - -<p>Page <a href="#Page_197">197</a>: No matching closing quotation mark for the opening -mark at “the small bright spot”.</p> - -<p>Page <a href="#Page_222">222</a>: Transcriber added an opening quotation mark at -“Down his back” to match the closing mark after -“He was seen by every one on board.”</p> - -<p>Page <a href="#Page_230">230</a>: No matching closing quotation mark for the opening -mark at “a whale of large size”.</p> - -<p>Page <a href="#Page_302">302</a>: Transcriber added an opening quotation mark at -“About fifty years ago” to match the closing mark after -“fed himself with the other.”</p> - -<p>Page <a href="#Page_372">372</a>: No matching opening quotation mark for the closing -mark after “its lower extremity.”</p> - -<p>Page <a href="#Page_385">385</a>: No matching closing quotation mark for the opening -mark at “sweeps off from”.</p> -</div></div> - - - - - - - - -<pre> - - - - - -End of Project Gutenberg's Pleasant Ways in Science, by Richard A. 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