UNIVERSITY OF IllWOtS 
 
 JUL 1 4 1915 
 
 SPECULATIONS. 
 
 SOLAR HEAT, GRAVITATION, 
 
 AND 
 
 SUN SPOTS. 
 
 By J. H. KEDZIE, Ph. D. 
 
 Whence are thy beams, O, Sun! thy everlasting light?— O ssian. 
 
 Some are much surprised that I should, as they think, venture to oppose 
 the conclusions of Newton; but here there is a mistake. I do not oppose 
 Newton on any point; it is rather those who sustain the idea of action at a 
 distance that contradict him.— Dr. Faraday. 
 
 The very source and font of day 
 Is dashed with wandering isles of night.— Belgravia. 
 
 SECOND EDITION. 
 
 CHICAGO: 
 
 S. C. GRIGGS AND COMPANY. 
 
 1891. 
 
Copyright, 1886, 
 
 By S. C. GRIGGS AND COMPANY. 
 
 KNIGHT £ LEONARD. 
 

 s 2/5. T 
 
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 «f? 
 
 To the Members and Fellows of the A. A. A. S. : 
 
 The maximum sun spot period is again approaching, 
 and so is the perihelion of Jupiter. These two grand 
 celestial phenomena have probably run their cycles in 
 equal times since the birth of our system, and will un- 
 doubtedly continue to do so while our system endures. 
 
 The period of Jupiter's perihelia is exactly 11 T 8 ¥ 6 F years, 
 that of the sun spot maximum is approximately the same, 
 though, from its nature, it cannot be sharply defined. 
 From this fact and all the other facts in relation to these 
 wonderful phenomena, which I need not here rehearse, I 
 cannot avoid the conviction that there is a physical con- 
 nection between the perihelia of Jupiter and the periods 
 of maximum solar maculation, though modified by the 
 action of all the other planets and satellites. The strong 
 interest excited by the reappearance of large spots on the 
 sun makes the present an appropriate occasion for again 
 calling the attention of scientists to the subject, and is 
 my excuse for presenting to the members and fellows of 
 this Society Part III of my work on Solar Heat, Gravita- 
 tion and Sun Spots. 
 
 The only favor I ask in return from those who have the 
 facilities and leisure for observations, especially by photo- 
 graphy, as well as from all others who may do me the 
 honor to read the pamphlet, is that they will immediately 
 communicate to me briefly their impressions, whether 
 from the book or from their own observations. 
 
 Very truly yours, 
 
 August 1, 1891. 
 
 J. H. Kedzie, 
 
 Evanston, 111. 
 
PREFACE. 
 
 HE author’s task is done, and it only remains for 
 
 him to apologize to the public for inflicting one 
 more book on a book-ridden world. 
 
 The public, however, cannot complain of a surfeit 
 of literature on the subject I have chosen. Probably 
 not one work has been written on the Sun — to us the 
 grandest and most beneficent object in nature — to one 
 million of fiction. 
 
 As will be ' seen from the title, the themes here 
 treated are three apparently disconnected subjects, but 
 if I am correct, they form a closely connected trinity, 
 depending upon a common principle. 
 
 The positions advanced in this work may seem bold 
 and, at first glance, revolutionary. But a closer view, 
 I trust, will convince the reader that not a single well 
 settled principle of science has been assailed. Thus : 
 On the subject of solar heat there are not less than five 
 or six different theories advanced by eminent scientists. 
 A new theory cannot, therefore, be considered as con- 
 flicting with any settled doctrine on this subject. 
 
 In regard to gravitation, the field is still more com- 
 pletely unpreoccupied. There is no settled doctrine as 
 to the cause of gravitation, and not even a plausible 
 
IV 
 
 PREFACE. 
 
 theory that I am aware of. It is equally true that there 
 is no settled doctrine among scientists in regard to the 
 cause of sun spots. A number of ingenious theories 
 have been advanced, but none have met with general 
 acceptance, and there is not one which even professes 
 to account for all the phases of those wonderful phe- 
 nomena. 
 
 The writer thought at one time that he would be 
 obliged to dissent from a generally accepted doctrine in 
 regard to “ potential energy ” ; but subsequent reading 
 showed him that he had been anticipated, in the views 
 advanced by at least two scholars of eminence — Judge 
 J. B. Stallo and S. To! ver Preston. 
 
 The writer, therefore, though a debtor to all scholars, 
 from the times of Copernicus to the present, has im- 
 pugned the accepted work of none. On the contrary, 
 he has addressed himself wholly to unsolved problems 
 in science. Since astronomers have swept the vault of 
 heaven with their magic tubes, and calculated the paths 
 of planets and satellites by the laws of projection and 
 gravitation, it cannot be considered presumptuous to 
 inquire reverently into the source of gravitation itself; 
 and if in so doing the suspicion arises, and will not 
 down, that gravitation is connected on one hand with 
 solar heat, and on the other with sun spots, by a single 
 well known principle, what is the w r riter to do but to 
 announce his suspicion, and give his reasons therefor ? 
 
 Though the writer has chosen to apply the term 
 
PREFACE. 
 
 V 
 
 “ speculations ” to tlie views herein advanced until in- 
 dorsed by higher authority, still he must confess that 
 not without some misgivings he has finally become a 
 convert to his own opinions. He has, therefore, no 
 apology to offer for advocating what he believes to be 
 true with all the earnestness and zeal which truth de- 
 mands of her votaries. 
 
 For all the facts and principles of value in the fol- 
 lowing pages, though not always for the use made of 
 them, the writer is indebted, as all the world is, first to 
 Sir Isaac Newton; and scarcely less to the great minds 
 of the present day. Though illustrious all, they are too 
 numerous to be mentioned by name. I desire to ac- 
 knowledge my indebtedness to all as fully as if I could 
 thank each one in person. 
 
 These chapters are most deferentially submitted by 
 the author to the candid judgment of the learned public. 
 He cannot expect, and would not desire, the acceptance 
 of the views here presented until it is found on the full- 
 est examination, that they conform to all the conditions 
 of truth, and conflict with no settled fact or principle of 
 science. 
 
 J. H. KEDZIE. 
 
 Evanston, III., May, 1886 . 
 
Digitized by the Internet Archive 
 in 2017 with funding from 
 
 University of Illinois Urbana-Champaign Alternates 
 
 https://archive.org/details/speculationssolaOOkedz 
 
PART III.- SUN SPOTS. 
 
 CHAPTER I. 
 
 GENERAL DESCRIPTION AND HISTORY. 
 
 The very source and font of day 
 Is dashed with wandering isles of night. 
 
 — Belgravia. 
 
 OR nearly three hundred years the scientific world 
 
 JL has been familiar with spots on the sun, discovered 
 almost simultaneously by Galileo, Fabricius, and Schei- 
 ner. An amusing incident is related of the latter, who 
 was a Jesuit brother. On informing his superior of 
 his discovery, and asking to be allowed to publish the 
 same, the superior replied : “ Go, my son ; tranquillize 
 yourself, and rest assured that what you take for spots 
 in the sun are the faults of your glasses or of your 
 eyes. I have read Aristotle's writings from end to end 
 many times, and I can assure you that I have nowhere 
 found in them anything similar to what you mention.” 
 
 To be more specific : The Jionored name of Galileo 
 is credited with the first discovery by telescope of sun 
 spots, in October, 1610. Fabricius followed closely 
 after, in December of the same year, and only a few 
 months later, in March, 1611, Scheiner made the same 
 discovery. All were original discoveries, as each worked 
 in entire ignorance of the labors of the others. As 
 Fabricius was the first to publish his discovery, in June, 
 
 219 
 
220 
 
 SUN SPOTS. 
 
 1611 , the discovery is credited to him, though the 
 others are entitled to equal honors. 
 
 As large sun spots are visible to the naked eye, many 
 were no doubt seen before the invention of the tele- 
 scope. The records of that curious people, the Chinese, 
 curious in two senses, afford evidence of such observa- 
 tions. Dark spots had also been observed by Kepler 
 and other European scholars before the invention of 
 the telescope ; but as they could not be examined in 
 detail, they attracted but little attention. 
 
 These spots are often of enormous extent, covering 
 sometimes millions and even billions of square miles. 
 They generally open as small points, enlarge rapidly 
 till they attain their maximum, and after a period of 
 comparative stability, varying from a few days to sev- 
 eral months, fill up and disappear. 
 
 They are mostly confined to that part of the sun’s 
 surface corresponding to our torrid zone, or rather to 
 two zones, one on each side of the equator, bounded by 
 parallels about thirty degrees north and south of the 
 equator. These zones of maximum sun spots shade 
 out each way, so that very few are found within ten 
 degrees of the equator,, or beyond thirty degrees north 
 and south of the same. 
 
 These spots are dark at the bottom and partially 
 lighted on the penumbral edges, which extend to the 
 depths of thousands of miles. 
 
 They increase and diminish in numbers at nearly 
 regular periods of about eleven years. The upland or 
 plain in which these crater-like openings appear is of 
 the substance denominated the sun’s photosphere ; that 
 is, the incandescent surface which sends forth the light 
 and heat of the sun. This, as I venture to conjecture, 
 
GENERAL DESCRIPTION AND HISTORY. 
 
 221 
 
 is composed of the sublimated vapors of carbon float- 
 ing in an atmosphere of metallic gases. Immediately 
 below the surface of the photosphere is the stratum of 
 penumbral clouds, no doubt composed of the same ma- 
 terials, but at a lower temperature. Still lower is the 
 nucleus or body of the sun, sometimes called the 
 umbra. The nucleus is generally believed to be liquid 
 in form, but by some to be composed of viscid gases. 
 The spectroscope seems to pronounce in favor of a 
 liquid, composed of the most refractory elementary 
 substances, reduced to that form by intense heat. 
 These spots often pass entirely across the sun’s disc 
 by virtue of his revolution, and have sometimes been 
 mistaken for the transits of inferior planets. The sur- 
 face of the nucleus is overlaid by transparent absorbing 
 gases, by the action of which the Frauenhofer lines 
 of the spectrum are produced. 
 
 The appearance of these spots in perspective at the 
 edges of the sun’s disc clearly shows that they are im- 
 mense chasms in the strata of the photospheric and 
 penumbral clouds, laying bare for the time the inner, 
 darker and cooler nucleus of the sun. 
 
 They are exceedingly variable in size and duration. 
 One has been seen almost two hundred thousand miles 
 in diameter, and covering an area of twenty-five billions 
 of square miles. Their duration also varies from a few 
 hours to whole days, weeks, and months. They form a 
 puzzle to philosophers. While the facts are obscure, not 
 for the want, but rather the excess, of light, and also the 
 immense distance of the sun, these philosophers have 
 not hesitated to draw largely upon their imaginations 
 for hypothetical explanations. There is no harm in 
 this, so long as they are given merely as hypotheses, 
 
222 
 
 SUN SPOTS. 
 
 and kept strictly within the limits of known facts. A 
 hypothesis, to be of any value, must conform strictly to 
 the known telescopic and spectroscopic conditions under 
 which these spots have been observed. 
 
 It is entirely unnecessary, even if I possessed the 
 time and qualifications for the task, to examine critically 
 all the theories advanced in explanation of these phe- 
 nomena. A number of them are peremptorily excluded 
 by telescopic and spectroscopic observations. Of those 
 remaining, no one is satisfactory to all students of solar 
 physics. Anticipating possibly a similar fate for my 
 own theory, I proceed to unfold it for what it is worth. 
 
 Fig. 12.— Spot of July 1G, 18G6. 
 
 We here call attention to a very symmetrical illus- 
 tration of a sun spot, from u The Sun,” by Prof. Young. 
 We quote from page 115, on which this figure occurs, 
 as follows: 
 
 “A well formed solar spot consists, generally speaking, of two 
 portions — a very dark, irregular, central portion, called the umbra, 
 
GENERAL DESCRIPTION AND HISTORY. 
 
 223 
 
 surrounded by a shade or fringe called the penumbra, less dark, and 
 for the most part made up of filaments directed radially inward. 
 The appearance of things, under ordinary circumstances of seeing, 
 is as if the umbra were a hole, and the penumbral filaments overhung 
 and partly shaded it from our view, like bushes at the mouth of a 
 cavern. I say as if, and very possibly this is the actual case, the 
 central portion being a real cavity filled with less luminous matter, 
 and depressed below the general level of the photosphere, while the 
 penumbra overhangs the edge.” 
 
 To my eye the penumbra resembles more nearly the 
 shelving banks of a deep excavation. This figure also 
 represents beautifully the bright points called “ gran- 
 ules,” and the dark reticulation called “ pores’ 5 in the 
 general surface of the photosphere. It also exhibits to 
 advantage the bright fringe, often club-shaped, at the 
 inner edge of the penumbra hereafter mentioned. 
 
CHAPTER II. 
 
 A NEW THEORY OF SUN SPOTS — THE PHOTOSPHERE 
 THE HOTTEST PART OF THE SUN. 
 
 And now the sun — 
 
 Insufferably brilliant, and his blaze 
 
 Tinges with flowing gold the icy head - 
 
 Of peaks which rise above the clouds, and gaze 
 
 On budding landscape, hills, woods, meadows, lakes, 
 
 Rivers, and winding rivulets, where plays 
 
 The wave in lines of silver. — Percival. 
 
 IIEN we find a rule to which there is no excep- 
 
 V V tion, it rises to the dignity of a law ; and one 
 law thoroughly understood and applied will often throw 
 a flood of light on many problems. The law to which 
 I wish to direct attention is, that the more highly an 
 elementary body is heated, the more brilliantly white it 
 becomes. Applied to the sun, we find the facute, which 
 are the crests of the photosphere, or the sun’s Hima- 
 layan mountains of light, are the most dazzlingly white. 
 The general surface of the photosphere is of a milder 
 intensity, and the brightness continues to decrease 
 through the penumbral strata to the nucleus, which 
 appears to be entirely black, of course by contrast. 
 The conclusion seems inevitable, that the outer envelope 
 of the sun, next to its purely gaseous atmosphere, is by 
 far the hottest portion. I regard the photosphere, with 
 its umbral and penumbral strata lying in immediate 
 contact with the nucleus, as a part of the sun rather 
 
 224 
 
A NEW THEORY OF SUN SPOTS. 
 
 225 
 
 than of his atmosphere, though of a vaporous or cloud- 
 like texture. 
 
 It has been demonstrated by actual experiments that 
 the photosphere is much hotter than either the pen- 
 umbra or nucleus. The spots themselves, as Henry, 
 Secchi, Langley, and others have shown, certainly 
 radiate to us less heat than the general surface of the 
 sun. According to the elaborate determinations of 
 Langley, the umbra of a spot emits about fifty-four per 
 cent, and the penumbra about eighty per cent as much 
 heat as a corresponding area of the photosphere.* 
 This shows that the heat of the photosphere is not pro- 
 duced by conduction or convection from the cooler 
 regions below, and consecpiently must come from with- 
 out. This photosphere is the fountain of all the sun’s 
 radiations, and must of necessity be the portion cooled 
 most rapidly. It must, therefore, have an ample source 
 of supply independent of the internal heat of the sun. 
 
 There seems but one conclusion possible, and that is 
 that the sun’s loss by radiation is supplied from without. 
 Whence can it come ? Only from other suns in a per- 
 petual round. The universal ether is proved to be cap- 
 able of conveying impulses of light and heat not only 
 in opposite, but in all possible directions at the same 
 time. The sun’s light and heat leave that luminary by 
 means of this ether. Can we doubt that they return 
 by the same medium? 
 
 That the planets are a family group and the sun their 
 father is not so much a figure of rhetoric as a literal fact. 
 There are many things looking toward a common origin 
 and of course a common nature for the whole solar sys- 
 tem, but not a common condition at the present time. 
 
 15 
 
 * “ The Sun,” by Young, page 159. 
 
226 
 
 SUN SPOTS. 
 
 Now the earth and all the other planets have this 
 property in common ; all the heat lost by them is radi- 
 ated from their outer surfaces, and all the heat received 
 by them to supply the loss and keep up the equilibrium 
 is received .at the surface from the sun and other celes- 
 tial bodies. Analogy would teach us the same thing is 
 true of the sun, if only we could find any adequate 
 source from which this heat could come. However 
 great may be the difficulty in finding such a source out- 
 side of the sun, the difficulty is augmented to an im- 
 possibility, if we look for such a source in the sun’s in- 
 terior. I have discussed this subject fully in another 
 place and have endeavored to show that there is no lack 
 of abundant supplies of light and heat accessible to the 
 sun to supply all his loss by radiation. 
 
 It is universally conceded, in view of the immense 
 amount of heat given off, that the sun, if unsupplied 
 from within or from without, would cool down with a 
 rapidity proportioned to the loss. It would only be a 
 question of time and, according to the best authorities, 
 a brief time at that, when the sun would be so far cooled 
 down as to render the earth uninhabitable. * 
 
 We will endeavor to gain an idea of the condition of 
 things in the sun by transferring the scene for a few 
 minutes to the earth. Let us imagine the earth to be 
 surrounded on all sides by a hollow sphere thickly 
 studded with suns as hot as ours and capable of raising 
 the whole body of the earth to an equal temperature. 
 What would take place ? 
 
 In the first place all organic substances, including 
 mineral coal and oils, would flash into one vast confla- 
 gration, equal in grandeur to the apocalyptic vision. 
 
 * Newcomb’s “Popular Astronomy,” page 518. 
 
A NEW THEORY OF SUN SPOTS. 
 
 227 
 
 The resulting forms would be mainly carbon dioxide, or 
 carbonic acid gas, and water in the form of steam. As 
 the heat continued to increase, this steam, together with 
 all the water in all the rivers, lakes and oceans also con- 
 verted into steam, would be decomposed; and the im- 
 mense volumes of hydrogen and oxygen, thus liberated, 
 would mount skyward, increasing our atmosphere to an 
 enormous extent. Not only this, but all the oxidized 
 earths and metals would be decomposed and the liber- 
 ated oxygen, heated to a degree far beyond the point of 
 chemical dissociation, would be added to the atmosphere, 
 still farther increasing its enormous volume. As if there 
 were not already gases enough in this atmosphere, the 
 ever increasing heat would first fuse and then volatilize 
 the iron, copper, zinc, and probably all the metals, un- 
 less we except platinum. The most refractory substances, 
 such as silicon and platinum would probably be fused, 
 and lastly would come the cataclysmic change in the de- 
 composition of the whole volume of carbon dioxide into 
 its elements, the oxygen joining the vast volume of the 
 gases, and the carbon, in the form of incandescent vapor 
 or of impalpable atomic dust, descending gently in 
 flocculent clouds of fire throughout the whole expanded 
 atmosphere. When these fiery vapors had settled down 
 to loose contact with the molten nucleus still remaining, 
 they would form a photosphere to the earth entirely 
 similar to that of the sun. 
 
 This carbon vapor, or impalpable white-hot atomic 
 dust, would at once know and assume its proper place, 
 intermediate between the pure transparent gases above 
 and the liquid silicon and more refractory metals com- 
 posing the core, as the receiver and radiator of the in- 
 tense heat of these surrounding suns. The transforma- 
 
228 
 
 SUN SPOTS. 
 
 tion would now be complete. The earth would be, in 
 all respects, a little sun. 
 
 This was probably once the condition of our earth, 
 but it has now cooled down so as to become the lit 
 abode of plants and animals, and even of frost and 
 snow. And yet not a particle of its heat has ever been 
 lost. While our earth has been cooling, some other 
 world or worlds have been warmed into fruitfulness as 
 the theatres for animal and vegetable life ; or if suns 
 were needed in the grand economy, the heat given off by 
 our earth has helped to kindle other suns, or still more 
 probably, the heat given out by our earth in cooling 
 has been replaced by tangential, rotary and gravitative 
 forces with other forms of energy at work on the sur- 
 face and in the interior of our globe. Whatever dispo- 
 sition has been made of the intense heat which at one 
 time lkpiefied, if it did not volatilize, the substance of 
 our earth, two things may be affirmed with absolute 
 certainty : One is that all this heat is somewhere and 
 in some form conserved, and the other is that it is all in 
 active operation, which is merely reaffirming its contin- 
 ued existence, for energy without action we have seen 
 to be impossible. 
 
CHAPTER III. 
 
 THE SUN’S HEAT DERIVED FROM THE ETHER, AND 
 
 NOT FROM HIS INTERIOR — CAUSE OF SUN SPOTS. 
 
 A golden axle did the work uphold, 
 
 Gold was the beam, the wheels were orbed with gold, 
 
 The spokes in rows of silver pleased the sight, 
 
 The seat with parti-colored gems was bright ; 
 
 Apollo shined amid the glare of light. — Ovid. 
 
 "TTTHAT we have imagined in the earth is exactly 
 V V what we find to be the existing state of things in 
 the sun. As the carbon vapors composing the photo- 
 sphere radiate all the heat which leaves the sun, it must 
 be cooled the most rapidly of any part; and, as it is 
 always the hottest part of the sun, it certainly cannot 
 derive its heat from the interior and cooler portions. 
 Consequently it must come from without ; from the sur- 
 rounding ether. 
 
 If this be true, then the sun will receive his heat on 
 all sides, and the poles will be as hot at least as at 
 the equator, if not hotter. This we find to be the case. 
 
 It maybe asked — in fact has been asked, “If the 
 photosphere is the hottest part of the sun, why does it not 
 by conduction raise the whole interior to the same tem- 
 perature ? ” I reply : The photosphere has other uses for 
 its surplus head in warming the earth and other worlds 
 and suns. Being in contact with the ether, it is much 
 easier to part with its heat by radiation than by the 
 slower process of conduction through gaseous media to 
 
 229 
 
230 
 
 SUN SPOTS. 
 
 the sun’s interior. At all events, fact is fact, whether 
 it suits our ideas or not. 
 
 Affirmatively, it appears to me highly probable that 
 the sun s])ots are produced by a relative lowering of the 
 temperature of the photosphere in the zones where the 
 spots occur. As it is held by all the best authorities 
 that the photosphere is composed of intensely heated 
 vapors (I think carbon vapors), in the form of clouds, 
 it would seem most natural that these clouds when 
 slightly cooled, should first be converted into a line 
 incandescent mist, then to fiery rain, hail or snow (if we 
 may use old words with new meanings), according to 
 the nature of the element or elements composing the 
 sun’s photosphere. In this way large regions of the 
 photosphere, if sufficiently cooled, would fall to the sun 
 in the form of solar rain, hail or snow, or, as I think, in 
 the form of impalpable carbon dust, leaving the inner, 
 cooler and darker surface of the sun uncovered, just as 
 clouds in our atmosphere, when condensed, descend in 
 the form of rain and snow, and leave the surface of the 
 earth previously covered with clouds open to the inspec- 
 tion of the inhabitants of other worlds. 
 
 The extent and duration of these spots would be as 
 variable as our “ spells” of weather, being produced by 
 similar causes, viz.: variations of temperature in the 
 enveloping atmospheres and clouds of the earth and 
 sun respectively. If our earth, like Jupiter, were 
 always covered by silver-lined clouds, with the lining 
 on the outside, and if only occasional rifts occurred, 
 exposing the earth’s surface, the inhabitants of other 
 planets would call them earth * spots, and the fleecy 
 
 * Unless the inhabitants of other worlds have other names for our planet. 
 
CAUSE OF SUN SPOTS. 
 
 231 
 
 clouds would form a mild kind of mundane photo- 
 sphere. 
 
 The variations in the temperature of our atmosphere 
 are easily accounted for by the extremely diversified 
 aspects in which the earth presents herself to the sun, 
 the source of her heat, owing to the variety in her mo- 
 tions and the inclination of her axis. But in the case 
 of the sun, if the theory that he receives his heat equally 
 from all parts of the celestial concave is correct, then 
 his cloudy envelope at least ought to be in a state 
 of comparative rest. Such we find to be the case. 
 Only two narrow belts, one on each side of the sun’s 
 equator, are affected by sun spots. Of course so unsta- 
 ble a thing as an ocean of incandescent hydrogen, 
 mingled with other gases, which occupy the higher 
 regions of the sun’s atmosphere, could hardly be ex- 
 pected to be entirely quiescent under any circumstances. 
 On the contrary, the most violent convulsions may be 
 expected in the upper regions of the sun’s atmosphere. 
 That this restful condition prevails in the sun’s photo- 
 sphere (not in his chromosphere and corona), seems 
 probable from the following considerations : 
 
 I believe every writer without exception considers 
 'the photosphere to be of vaporous or cloud-like texture. 
 Consequently it would yield with the greatest readiness 
 to any disturbing force affecting it or the gaseous 
 medium in which it floats. But the sun spots, which all 
 admit to be cavities in the photosphere, remain not only 
 for days and weeks, but often for months without being 
 obliterated. The comparatively restful condition of 
 the sun’s cloudy envelope forms no slight corroboration 
 of the truth of this theory. 
 
232 
 
 SUN SPOTS. 
 
 CAUSE OF SUN SPOTS. 
 
 We will now address ourselves to an attempt to 
 ascertain the cause of sun spots. 
 
 I attribute the cooling of the portions of the sun’s 
 photosphere, comprised in the maculated belts (by 
 which large fields of fiery clouds are precipitated, and 
 the sun’s .surface uncovered), to the shadows cast upon 
 the sun by Jupiter and the other planets. If the source 
 of the sun’s heat is the whole celestial concave, then 
 these planetary bodies and their satellites, mainly lo- 
 cated within the limits of the zodiac, are the only 
 bodies that could intercept any portion of the waves 
 inundant on the sun. 
 
 Of course, the shadows cast by the heavenly bodies 
 are very different from those we are familiar with on the 
 earth. The former are dynamic, or rather anti-dynamic. 
 They are simply the aggregate of the shadows of the 
 particles composing these bodies. I hope no one will 
 decide authoritatively that the effect of these shadows 
 combined must of necessity be infinitesimal, while he 
 admits that a force which we call gravitation is exerted 
 between the sun and these same bodies, which is by no 
 means infinitesimal. In fact, we claim that the energy 
 intercepted from the sun by these bodies is identical 
 with gravitation. It consists, as we conceive, of waves 
 of mechanical force, turning to heat when intercepted, 
 coming from the celestial concave, which would, if un- 
 intercepted, make the equatorial regions of the sun 
 equally hot with his poles, but being intercepted, ex- 
 pends itself in bending the tangential motion of the 
 planets into the curved lines of their orbits. In conse- 
 quence of the diversion of this intercepted energy to 
 
CAUSE OF SUN SPOTS. 
 
 233 
 
 the purposes of gravitation, the sun experiences a defi- 
 ciency, greatest near his equator, where the intercepted 
 rays woulj have been vertical, and shading out toward 
 the poles. 
 
CHAPTER IV. 
 
 ARGUMENT FROM THE UNEQUAL ROTATION OF THE 
 SUN SPOTS. 
 
 Thou chief star, 
 
 Centre of many stars which mak’st our earth 
 
 Endurable and temperest the hues 
 
 And hearts of all who walk within thy rays! 
 
 Sire of the seasons! Monarch of the climes, 
 
 And those who dwell in them ! for near or far, 
 
 Our inborn spirits have a tint of thee, 
 
 Even as our outward aspects : thou dost rise, 
 
 And shine, and set in glory. — Byron. 
 
 IIE sun at his equator revolves on his axis in about 
 
 -L twenty-five days. At twenty degrees north and 
 south latitude he appears to revolve in twenty-five 
 and three-fourths days; at thirty degrees in twenty- 
 six and a half days, and at forty-five degrees in 
 about twenty-seven and a half days. IIow does this 
 accord with the theory here advanced? If the fiery 
 clouds composing the photosphere are relatively cooler 
 at and near the equator, then a circulation will be 
 set up, analogous to the circulation of the cloud-bearing 
 winds on the earth. But as the zones are reversed 
 so will be the circulation. The cooler portions of 
 the photosphere will sink down and how out as the 
 under currents from the equatorial regions of the sun 
 toward his poles. These out-flowing currents will leave 
 the equatorial regions with the rotary velocity of the 
 nucleus, but will be continuously retarded by friction 
 
 234 
 
UNEQUAL ROTATION OF THE SUN SPOTS. 
 
 235 
 
 till they reach the polar regions, by which time they 
 will have accommodated themselves to the slower mo- 
 tion of the nucleus at the poles. By intermingling and 
 coming to the surface, these currents will also by this 
 time have acquired the higher temperature of the polar 
 regions where no shadows are cast upon the sun. They 
 will then start on their return toward the equator as 
 the upper and hotter currents, but with the compara- 
 tively slow rotary motion of the polar regions. As 
 these currents appoach the equator, they will lag be- 
 hind the motion of the body of the sun most at first, 
 but will become gradually accelerated as they approach 
 the equator, till, on arriving in the equatorial regions, 
 they will have regained the rotary velocity of the nu- 
 cleus at the equator, precisely as the cloud-bearing 
 winds on the earth are alternately accelerated and 
 retarded in their rotary motion in accommodating them- 
 selves in turn, now to the swift motion of the equato- 
 rial, and then to the slow motion of the polar regions 
 of the earth, only in a reversed order. This circulation, 
 on the supposition of a relatively cooler zone extending 
 for some distance north and south of the equator, is 
 inevitable. The result will be that the photosphere in 
 the equatorial regions will keep pace with the body of 
 the sun. But north and south of the equator the upper 
 and visible portion of the photosphere, in which the 
 spots are seen, will lag behind in its rotary motion in- 
 creasingly from the equator toward the poles. 
 
 The result of these currents must inevitably be that 
 the photospheric envelope of the sun will keep pace 
 with his body at the equator, performing a revolution 
 in twenty-five days, while those portions north and 
 south of the equator, with their included spots, will be 
 
236 
 
 SUN SPOTS. 
 
 retarded, and will take longer time to perform a revo- 
 lution, just in proportion to their solar latitude. This 
 is exactly what has been found to be the case by the 
 patient and careful observations of Carrington from 
 1853 to 1861 * 
 
 I can see no probable, nor even possible, explanation 
 of the slower motion of the sun spots north and south 
 of the equator, except on the supposition of such a cir- 
 culation as I have described ; and such a circulation can 
 only be produced by a cooler zone at and near the 
 equator. 
 
 We call these grand movements of the photospheric 
 and penumbral clouds currents , for want of a better 
 term. If I am correct, they constitute very slow mass 
 movements of the whole vast volume of the sun’s 
 cloudy envelope. 
 
 I have elsewhere shown that owing to the fact that 
 the sun receives his heat almost equally on all sides, 
 there are no great inequalities in the temperature of 
 different parts of the solar surface, and consequently no 
 violent currents, as upon the earth. This is proved by 
 the somewhat permanent character of the spots. These 
 generally remain for some days, and often for weeks 
 and months, with but slight alterations in form. If 
 violent winds were sweeping over the face of the sun, 
 the spots, being of a cloudy nature, would be swept 
 away as soon as formed. The flashes and streamers 
 sometimes observed are generally considered to be 
 auroral, and not a transference of actual matter. 
 
 Still, there are undoubtedly the slow currents of cir- 
 culation I have described. In general, they are divided 
 into upper and lower currents, as in our atmosphere, 
 
 See “The Sun,” by Young, pages 133 and 134. 
 
UNEQUAL ROTATION OF THE SUN SPOTS. 
 
 237 
 
 only reversed, as the cooler and hotter zones are re- 
 versed. But, as in onr atmosphere, so in the sun, these 
 currents sometimes clash and become mixed. 
 
 In the sun’s northern hemisphere, the currents, both 
 upper and lower, relatively to the solar surface as seen 
 by us, are northwest and southeast. It will be remem- 
 
 s 
 
 Fig. 13 . 
 
 bered that the sun’s apparent rotary motion, as seen by 
 us , is from east to west. These upper and lower cur- 
 rents will be parallel with each other, but in opposite 
 directions. 
 
 If the arrows represent different intermingling cur- 
 rents, it is plain that, should a sun spot be located 
 
238 
 
 SUN SPOTS. 
 
 between the currents a b and c d , their edges would 
 revolve from left to right, like the hands of a watch ; 
 the same between e f and g h ; but between the cur- 
 rents c d and e f, and also between g h and i j , they 
 would revolve from right to left. This we find to be 
 the case, exhibiting occasionally the appearance of 
 cyclones, but revolving sometimes in one direction, and 
 at others in an opposite one. Can this be accounted 
 for on any other hypothesis ? 
 
 Fig. 14.— Cyclonic Sun Spot, by Secchi. 
 
 The only writer, so far as I am aware, who lias 
 attempted to account for the cyclonic character of the 
 spots is the ingenious French writer, Faye. But his 
 theory would require, not some only, but all , the spots 
 to lie vortical, and would further require all spots north 
 of the sun’s equator to rotate from right to left, and 
 all south of the equator, from left to right ; whereas, it 
 is well known that only a small proportion of the spots 
 rotate at all ; and of those which do, some rotate in one 
 
UNEQUAL ROTATION OF THE SUN SPOTS. 
 
 239 
 
 direction, and some in the other, in the same hemi- 
 sphere. Still, the theory is a good one, and all that is 
 necessary is to make the spots conform to it. 
 
CHAPTER Y. 
 
 DISTRIBUTION OF SUN SPOTS. 
 
 Alcyone shines with a force of twelve thousand suns. And then 
 we have suns themselves combined into systems of all sizes and 
 shapes — systems of two, of three, of many, of millions — firma- 
 ments which, under the name of nebulae, are the last generalization 
 and most stupendous variety of modern discovery; sometimes rolled 
 up into spheres; sometimes gathered into circular or elliptic rings: 
 now fan shaped ; now like an hour glass ; now broad wheels of com- 
 pacted suns, large, glittering, and sublime enough to under-roll the 
 chariot of Omnipotence. — Pater Mundi. 
 
 S UCH is a glowing description, not altogether ima- 
 ginative, of the suns of space by one of the most 
 eloquent writers of modern times. There is but one of 
 this innumerable host that we can examine with any- 
 thing like exactness. But from this one we can learn 
 more than from all the rest combined. 
 
 One of the most interesting facts in regard to the 
 “wandering isles of night,” called sun spots, is their 
 peculiar and permanent manner of distribution upon 
 the solar surface. 
 
 We have seen that they are confined almost entirely 
 within two parallels, thirty degrees north and south of 
 the sun’s equator, diminishing in frequency toward the 
 northern and southern boundaries of these belts, and 
 also toward the equator. 
 
 Figure 15 on the opposite page represents the sun 
 with the plane of his equator inclined to that of the 
 
 240 
 
Fig. 15. 
 
 DISTRIBUTION OF SUN SPOTS. 
 
 241 
 
 S ty 
 
 | 
 
 iMil I 
 
 s/ h ■# 
 
242 
 
 SUN SPOTS. 
 
 ecliptic, or plane of the earth’s orbit, at an angle of 
 seven and one-quarter degrees, together with the planes 
 of the four other planets nearest the sun. 
 
 The planes of the three exterior planets are omitted 
 for the triple reason : 1, because from their great dis- 
 tance they can have but very little influence upon sun 
 spots; 2, in a small figure the planes would be so 
 crowded as nearly to obliterate each other ; and, 3, be- 
 cause the principle can be as well illustrated by the five 
 nearer planets as by all. It will be seen that during 
 one-half of the years respectively of each of the planets, 
 their orbits are above, and during the other half below, 
 the sun’s equator. As the planetary years differ greatly 
 in length, the planets, at a rough average, will at all 
 times be distributed in nearly equal proportions north 
 and south of the sun’s equator, as well as in their direc- 
 tions from the sun. The dotted lines will represent 
 those parallels on the sun to which Mercury, Jupiter, 
 and Venus respectively will be vertical at their extreme 
 northern and southern limits. They, of course, repre- 
 sent the lines on which these planets respectively would 
 be most influential in producing sun spots at these 
 times. But the planets remain at their extremes of 
 north and south latitude for a short time only, and 
 during each revolution become in turn twice vertical to 
 the equator and every parallel on the sun between these 
 extremes. 
 
 One only of the planets, Mercury, but a very influ- 
 ential one on account of his proximity, ever extends 
 his north and south latitude sufficiently to make his 
 shadow vertical to the centres of the maculated belts, 
 and, of course, only for a short time at each revolution. 
 All the other planets, including those omitted from the 
 
DISTRIBUTION OF SUN SPOTS. 
 
 243 
 
 figure, oscillate from one side of the sun’s equator to 
 the other within much narrower limits. 
 
 This would indicate that the average of all the 
 shadows cast by all the planets must be densest at and 
 near the equator, fading out in both directions; and 
 the sun spots, if they knew how to behave themselves, 
 would be most numerous at and near the equator, and 
 would shade out each way to about their present boun- 
 daries. 
 
 But as the spots will not conform to our theories, let 
 us see if our theory can be accommodated to the spots. 
 
 It matters not at what point we start in to accom- 
 pany the currents in the pliotospheric and umbral 
 clouds, which, as we believe, circulate from the equator 
 to the poles and back again. We will therefore join 
 them in imagination at the poles, or (confining ourselves 
 for the present to the sun’s northern hemisphere) at the 
 north pole. Here the photosphere is exposed to the 
 hottest of the solar skies, and becomes heated to the 
 highest temperature which these clouds ever attain. 
 Thus heated they start toward the equator, but with 
 the very slow rotary motion of the circumpolar regions 
 of the sun. The result is that they will lag behind the 
 body of the sun during their whole progress from the 
 pole to the equator, and when the currents reach the 
 maculated belts, the spots will also lag behind just in 
 proportion to their solar latitude. When these cur- 
 rents reach the northern boundary of the maculated 
 belt, to the centre of which Mercury is vertical once in 
 every eighty-eight days, they begin to feel the cooling 
 influence of the planetary shadows, and the spots com- 
 mence to appear, though sparsely at first. 
 
 I believe there is no dissent among scholars as to the 
 
244 
 
 SUN SPOTS. 
 
 belief that even what are called the pores on the sun’s 
 surface are intensely hot and brilliantly white, and that 
 they only appear dark by contrast with the still hotter 
 and more brilliant granules and faculse of the sun. 
 
 It is well known that almost the whole surface of 
 the sun is made up of these granules and pores — the 
 pores being in the proportion of four to one of the 
 granules and much cooler than the latter. If the mat- 
 ter of both is the same, as can hardly be doubted, then 
 the whole surface of the sun is nicely balanced on the 
 dividing line between the granular and porous condi- 
 tions. A slight increase in temperature would convert 
 the pores into granules and a slight lowering would 
 convert the granules into pores. 
 
 To continue our imaginary journey : When these 
 currents in their southward progress have reached the 
 parallel of twenty degrees, the spots become most nu- 
 merous. As they approach the equator, the spots again 
 decrease, till at about ten degrees they almost entirely 
 disappear. 
 
 On approaching the equator the currents, being now 
 considerably cooled, dive down to the sun’s nucleus and 
 commence the return voyage as the undercurrent 
 toward the pole. This journey is without incident, ex- 
 cept that the upper and lower currents sometimes clash 
 and intermingle to a certain degree, as in the cloud- 
 bearing atmospheric currents on the earth, and thus 
 cause occasional cyclonic action in the spots. These 
 lower currents are but slightly cooler than the upper 
 ones, but sufficiently so to make their substance, like 
 the pores, appear black by contrast. 
 
 This is the place to state that, according to the 
 theory here advanced, the sun spots do not extend 
 
DISTRIBUTION OF SUN SPOTS. 
 
 245 
 
 downward to the nucleus of the sun, hut only to this 
 blackened undercurrent of umbral clouds. We are 
 now prepared to consider the question : Since the 
 shadows of the combined planetary system are densest 
 on and near the equator, why should not the spots be 
 most numerous in this part of the sun ? 
 
 We reply that, at the solar equator, and for some dis- 
 tance north and south of the same, this celestial Niagara 
 of glowing carbon clouds, inconceivably hot, notwith- 
 standing their slight comparative cooling by the plane- 
 tary interceptions, dives down to an unknown depth 
 and then turns northward and southward toward the 
 poles. Now suppose an ambitious pore on the upper 
 surface of this perpendicular downward current should 
 attempt to expand itself into a magnificent sun spot, the 
 downward current would swallow it up before it could 
 be formed. Besides this; if a sun-spot opening could 
 be formed in the upper surface of this downward cur- 
 rent, it would not be based, as in the other cases, upon 
 the blackened surface of the under current, which is not 
 yet fully formed. Thus a spot, if it existed on or near 
 the equator, would seldom be visible for want of a 
 darker background. 
 
 It seems certain that the edges of some of the sun 
 spots, under the influence of some mysterious process, 
 take on forms of grace and beauty somewhat resem- 
 bling arborescent frost w r ork on glass, finely depicted in 
 Prof. S. P. Langley’s illustrations, Figs. 18 and 21, and 
 also in Figs. 16 and IT. 
 
 We may well believe that between the parallels of 
 ten degrees and thirty degrees the restful condition 
 of the photosphere, under the cooling influence of the 
 planetary shadows, is highly favorable to the formation 
 
246 
 
 SUN SPOTS. 
 
 first of enlarged {lores developing into the large areas 
 of precipitation known to us as sun spots, and that the 
 tumult and rush of the downpour at and near the 
 equator are equally unfavorable, so that spots here will 
 be correspondingly rare; 
 
 Thus we see that, though the planets do not, and, in 
 the nature of things, cannot, cast their shadows in two 
 zones corresponding to the maculated belts, still, ow- 
 
 Fig. 16.— Sun Spot of July 31, 1869. 
 
 ing to the peculiar nature of the circulation in the plio- 
 tospheric and urnhral clouds, in connection with the 
 planetary shadows, the double-belted distribution is 
 effected. 
 
 It may be replied : What proof have wc of the ex- 
 istence of this circulation ? We answer: Two undenia- 
 ble facts. One is the lagging motion of the sun spots, 
 and the other, their occasional cyclonic action. I know 
 
DISTRIBUTION OF SUN SPOTS. 
 
 247 
 
 of no possible way of accounting for either of these 
 phenomena except by such a circulation. 
 
 Another fact is equally convincing. If it be con- 
 ceded, or has been proved, that the sun receives his sup- 
 ply of heat from the stellar concave through the ether, 
 then it is as certain that the planets must intercept a 
 portion of the energy which supplies this heat, as that a 
 screen held between a lighted candle and a wall must in- 
 tercept a portion of the light of the former from the latter. 
 It is just as certain that, if motion, or energy convertible 
 into heat, be intercepted from the equatorial region of 
 the sun, a circulation in the fleecy clouds of the photo- 
 sphere and umbra must be produced. 
 
 We confess that it seems presumptuous for man with 
 his limited powers to intrude “ where angels might fear 
 to tread.” We stand awe-struck in the presence of 
 this king of day, and hardly dare admit to ourselves 
 that we are able to penetrate the profound secrets of 
 his being. But, if we are not to study the sun, why is 
 he allowed to exhibit himself to us in all his glorious 
 pomp, and why were we endowed with the powers and 
 the desire to investigate his awful mysteries ? 
 
CHAPTER VI. 
 
 PERIODICITY OF SUN SPOTS. 
 
 Nature is one eternal circle. — Percival. 
 
 T HE sun spots increase and diminish in fairly, but 
 not sharply, defined periods of about 11.111 years, 
 according to Wolf. 
 
 How, all the planets move in orbits more or less 
 elliptical. It is manifest that the nearer any planet is 
 to the sun — that is, the nearer it is to its perihelion — 
 the denser will be the shadow cast by it upon the sun. 
 The mass of each planet, divided by the square of its 
 distance, will express its relative cooling influence upon 
 the sun. Jupiter, from his immense mass (being three 
 hundred and thirty-eight times that of the earth, and 
 more than double that of all the other planets com- 
 bined), as well as from his relative distance and eccen- 
 tricity of orbit, would necessarily dominate in the mat- 
 ter of sun spots. Still, he will sometimes be assisted, 
 and at others antagonized, by the influence of the other 
 planets, so far as hastening or delaying the maximum 
 periods is concerned. 
 
 For example, every forty-ninth perihelion of Mer- 
 cury, every nineteenth of Venus, every twelfth of the 
 Earth, and every sixth of Mars, will very nearly syn- 
 chronize with those of Jupiter. At these times the 
 maxima will probably be more marked ; at others, less 
 so. A. Guillimin, in his work, u The Sun,” page 209, 
 
PERIODICITY OF SUN SPOTS. 
 
 24:9 
 
 in a note, speaking of Warren De La Rue, Balfour 
 Stewart, and Loewy’s studies in relation to the influ- 
 ence of Jupiter, says : 
 
 “They appear to have observed that when one of these planets 
 passes across the plane of the sun’s equator, it drags, as it were, the 
 spots into the equatorial region of the disc; they spread toward the 
 poles, on the contrary, when the planets pass away from the equatorial 
 plane.” 
 
 This negative cause of sun spots, through cooling by 
 planetary shadows, as well as their distribution, is won- 
 derfully confirmed by a writer in Belgravia, No. 13, 
 page 51, without knowing or intending it, thus : 
 
 “But it was reserved for the patient, day-by-day watchers and 
 draughtsmen of our time to discover that, as Venus rolls in her 
 inclined orbit around the luminary, the spots retreat farther from 
 the equator as the planet increases her solar latitude; in other 
 words, that there is a tendency in the spots to locate themselves per- 
 pendicularly under the planet. 
 
 “Another curious fact evolved from the daily chronicling is that 
 when Mercury passes between Venus and the sun, the spots come 
 forth in the fullest splendor, and there is more than a suspicion that 
 Mars, in conjunction with one of the inferior planets, is influential 
 in increasing the area of the spottiness.” 
 
 This writer might have added that Jupiter, and all 
 the other planets, in proportion to their respective 
 masses and proximity to the sun, aid in producing this 
 “ spottiness,” and that their solar latitude influences, if 
 not absolutely determines, the latitude of the spots. 
 
 After reading these extracts, how is it possible to 
 doubt that the spots are produced by the shadows of 
 these and the other planets projected on the sun ? 
 
 Adopting Wolf ’s periods of sun-spot maxima from 
 1015 to 1870, a period of two hundred and fifty-five 
 years,* I have copied the following table, exhibiting 
 
 *See “ The Sun,” by Young, page 148. 
 
250 
 
 SUN SPOTS. 
 
 in parallel columns, first, the dates of Jupiter’s peri- 
 helia ; second, the dates of the corresponding sun-spot 
 maxima ; third, the intervals between successive sun- 
 spot maxima. 
 
 Jupiter’s 
 
 Perihelia. 
 
 Sun Spot. 
 Maxima. 
 
 Sun Spot. 
 Interval. 
 
 Jupiter’s 
 
 Perihelia. 
 
 Sun Spot. 
 Maxima. 
 
 Sun Spot. 
 Interval. 
 
 1607.95 
 
 1615.50 
 
 
 1762.13 
 
 1761.50 
 
 11.20 
 
 1619.81 
 
 1626. 
 
 10.50 
 
 1773 99 
 
 1769.70 
 
 8.20 
 
 1681.67 
 
 1639.50 
 
 13.50 
 
 1785.85 
 
 1778.40 
 
 8.70 
 
 1643.53 
 
 1649. 
 
 9.50 
 
 1797.71 
 
 1788.10 
 
 9.70 
 
 1655.39 
 
 1660. 
 
 11. 
 
 1809.57 
 
 1804.20 
 
 16.10 
 
 1667.25 
 
 1675. 
 
 15. 
 
 1821.43 
 
 1816.40 
 
 12.20 
 
 1679.11 
 
 1685. 
 
 10. 
 
 1833.29 
 
 1829.90 
 
 13.5) 
 
 1690.97 
 
 1693. 
 
 8. 
 
 1845.15 
 
 1837.20 
 
 7.30 
 
 1702.83 
 
 1705.50 
 
 12.50 
 
 1857.01 
 
 1848.10 
 
 10.90 
 
 1714.69 
 
 1718.20 
 
 12.70 
 
 1868.87 
 
 1860.10 
 
 12. 
 
 1726.55 
 
 1727.50 
 
 9.30 
 
 1880.73 
 
 1870.60 
 
 10.50 
 
 1738.41 
 
 1750.27 
 
 1738.70 
 
 1750.30 
 
 11.20 
 
 11.60 
 
 
 1881.70 
 
 11.10 
 
 The average interval, according to Wolf, is 11.111 
 years, while the Jovian period is 11.86. This resem- 
 blance between the two periods has been sufficient to 
 attract the attention of every writer on the subject. Still 
 there is sufficient discrepancy, coupled with the irregular- 
 ity in the intervals of the maximum periods, to puzzle 
 the philosophers and baffle all attempts to bring them 
 into any certain relation to the perihelion periods of 
 Jupiter. Much less lias anyone attempted to point out 
 any relation of cause and effect between the two, and 
 still less, the nature of that cause. 
 
 Though the Jupiter of astronomy is not chargeable 
 with the fickleness and follies of the Jupiter of mythol- 
 ogy, there certainly seems to be a perverse refusal on 
 the part of the former to scpiare his conduct with the 
 periods of sun-spot maxima. Still, rather than throw 
 aside as worthless so interesting, though imperfect, a cor- 
 
PERIODICITY OF SUN SPOTS. 
 
 251 
 
 respondence, as all writers on the subject, so far as I 
 know, have done, I would prefer to see if some plan of 
 reconciliation cannot be discovered. 
 
 A preliminary observation, in which all will agree 
 with the writer, is, that the investigation of this subject 
 properly belongs to astronomers only. But anyone may 
 offer suggestions to be taken only for what they are 
 worth. 
 
 My first observation then is that sun spots per- 
 tain wholly to what may be called solar weather, or 
 changes in solar temperature. The weather in the sun, 
 though far less complicated than that of the earth, par- 
 takes, to some extent, of the same nature, and that na- 
 ture precludes the possibility of that exactness in calcu- 
 lation, which the sublime science of astronomy has 
 attained in regard to the motions of the heavenly bodies. 
 
 It is manifest from the table that the first ten sun- 
 spot maximum periods, as compared with the corre- 
 sponding perihelia of Jupiter, all occurred after Jupiter 
 had circled through the whole, or nearly the whole, of 
 the perihelion half of his orbit and had retired to the 
 neighborhood of his aphelion, or even beyond, leaving 
 in his wake, according to the theory here advocated, a 
 cold streak encircling the sun once every twenty-five 
 days. If “ coming events cast their shadows before,” it 
 is no less true that departing events leave their shadows 
 behind. 
 
 Though, in these cases, Jupiter has, for about six 
 years on an average, been streaking the body of the sun 
 like the cylinder of the phonograph, with lines of 
 lower temperature, he certainly has enjoyed the aid of 
 the perihelion periods of other planets in bringing out 
 the sun-spot maxima. In the cases where the maxima 
 
252 
 
 SUN SPOTS. 
 
 lag behind the perihelia of Jupiter, the other perihelia 
 which have supplemented his work have followed at a 
 respectful distance behind those of the former. 
 
 From 1769 to the end of the series included in this 
 table nearly the same process is repeated as from 1615 
 to 1718. The sun-spot maxima occur after Jupiter has 
 swept through the perihelion half of his orbit in most of 
 the cases, and in some has passed on to and even beyond 
 his aphelion. In this latter series, as in the first, it is 
 undoubtedly true that the sun-spot maxima have in part 
 been produced by the perihelia of other planets follow- 
 ing at considerable distances behind those of Jupiter. 
 
 Between 1615 and 1881, or in two hundred and six- 
 ty-six years, twenty-four sun-spot maxima have occurred, 
 as generally reckoned, but only twenty-three Jovian pe- 
 riods. In other words, there seems to be a slow, though 
 somewhat irregular precession of the sun-spot maxima 
 over the Jovian periods, gaining one sun-spot cycle in 
 about two hundred and sixty-six years. 
 
 Observers are not fully agreed as to the number of 
 maximum periods between 1615 and 1881. If we were 
 allowed to deduct one, it would make the number of 
 sun-spot maxima correspond exactly with the number of 
 Jovian periods. Will the reader have the goodness to 
 recur to the table and observe that between 1761.50 and 
 1788.10 — an interval of 26.60 years — three successive 
 maximum periods are included, averaging only 8.86 
 years each. Whereas, the general average is 11.11, or, 
 allowing the deduction, 11.86. If these three could be 
 reduced to two, without doing violence to the facts of 
 observation, it would show such a close correspondence 
 between the average of the sun-spot cycles and the pe- 
 riods of Jupiter as would, I believe, convince every can- 
 
PERIODICITY OF SUN SPOTS. 
 
 253 
 
 did reader that the latter are responsible for the former. 
 We could hardly refrain from crying, “ Eureka!” 
 
 In the few cases between 1718 and 1769 where the 
 sun-spot maxima and the Jovian perihelia were nearly 
 contemporaneous, the perihelia of other planets which 
 did the preliminary work, leaving the finishing strokes 
 only to Jupiter, evidently preceded those of Jupiter. 
 
 That there were such preceding and following peri- 
 helia of other planets goes without saying. Mercury 
 is in perihelion every eighty-eight days. Venus follows 
 once in every two hundred and twenty-five days, while 
 Earth and Mars are in perihelion every three hundred 
 and sixty-five days and six hundred and eighty-seven 
 days respectively. As to their exact positions while 
 rendering to Jupiter their aid, we prefer to leave them 
 to the exact calculations of the practical astronomer, 
 rather than to the bungling figures of an inexpert. 
 
 I shall not be surprised to learn from those compe- 
 tent to make the calculations that every variation 
 between the Jovian periods and the sun-spot cycles can 
 be accounted for by intervening planetary perihelia. 
 
 The general law, I apprehend, might be expressed 
 thus : Let the mass of each of the planets, including its 
 satellites and each of the planetoids be divided by the 
 square of its distance from the sun ; then the sun spots, 
 in number and magnitude, will vary directly as the 
 sum of these quotients. 
 
 This expresses the order only of the changes. The 
 time that will elapse between the occurrence of the 
 cause and the exhibition of the effect will always be 
 considerable, just as our coldest weather occurs some 
 time after the winter solstice, and our hottest after the 
 summer solstice. The length of these intervals is not 
 
254 
 
 SUN SPOTS. 
 
 only unknown beforehand, but is subject to considera- 
 ble variations in different Jovian years. 
 
 This law might be more loosely and popularly ex- 
 pressed thus : The nearer the whole aggregate mass of 
 planetary matter is to the sun, the more effective, nega- 
 tively, will be the penumbral shadows or negations of 
 energy, or the greater will be the number of rays of 
 mechanical motion convertible into heat, intercepted 
 from the sun, and the more will his photosphere between 
 the limits of the zodiac and for some distance beyond, 
 be cooled and condensed, and the greater will be the 
 number and size of the openings through the photo- 
 spheric clouds called sun spots. But the intervals 
 between these periods of greatest average proximity 
 and the occurrence of the sun-spot maxima are variable 
 within certain limits. 
 
 But with these small concessions to Mercury, Venus 
 and the other inferior deities, Jupiter, as might be 
 expected, has no doubt ruled in the heavens for ages 
 before his worship was celebrated on Mount Olympus. 
 He dominates in the matter of sun spots, but he is 
 obliged to share his sovereignty with every planet, 
 every satellite, and every asteroid, that circles round the 
 sun. Every body, large or small, situate between the 
 celestial concave and the maculated belts of the sun, 
 helps to cast shadows, or negations, upon the latter, and 
 by so doing deprives these portions of the sun of a cer- 
 tain amount of mechanical motion convertible into 
 heat, which all other portions of the sun receive in un- 
 diminished plenitude and intensity. 
 
 These shadows of intercepted energy cause a relative 
 cooling of the photosphere of the spotted belts and a 
 condensation of the photospheric clouds in “ spots,” thus 
 
PERIODICITY OF SUN SPOTS. 
 
 255 
 
 opening rifts through which we catch glimpses of the 
 interior of the sun. 
 
 The relation between sun spots and terrestrial mag- 
 netism is well established and highly interesting, but all 
 that is known on the subject can easily be found in the 
 works of more learned writers. It is highly probable, 
 though not yet fully demonstrated, that the years of sun- 
 spot maxima are slightly cooler than the average. If 
 so, though I have not investigated the subject, it may 
 be found that in these years the grasses and cereals, 
 except maize, have been abundant, while during the 
 minimum periods, the reverse has been the case. 
 
CHAPTER VII. 
 
 TIIE PHOTOSPHERE PROBABLY COMPOSED OF INCAN- 
 DESCENT CARBON VAPOR. 
 
 The sun’s high palace, on high columns raised, 
 
 With burnished gold and flaming jewels blazed. 
 
 —Ovid. 
 
 I T is the almost universally received opinion that the 
 sun and planets have a common origin. It is not 
 simply suspected, hut fully demonstrated, that a major- 
 ity of the best known elementary substances which 
 compose the earth exist also in the sun. As to the 
 mundane elements that have not been discovered in the 
 sun, we may well believe that their presence has not 
 been detected, through the imperfections of our means 
 of observation. 
 
 As the sun has only one-fourth the density of the 
 earth, these materials must be in forms much more 
 expanded than in the earth. 
 
 This need not, however, be gaseous, so far as the 
 nucleus or inner core is concerned. It is much more 
 probable, in my opinion, though I cannot stop here to 
 give the reasons, that the inner portion of the nucleus 
 is liquid, or possibly composed of the most refractory 
 solids, held in this form by enormous pressure. The 
 outer portions, being subjected to the action of greater 
 heat and less pressure, are known to exist in the gas- 
 eous form. 
 
 As the elements of the earth and sun are mainly, if 
 
 256 
 
INCANDESCENT CARBON VAPOR. 
 
 257 
 
 not entirely, tlie same, it is highly probable that they 
 exist in the two bodies in similar proportions. As 
 about one-half the mass of the earth is composed of 
 oxidized silicon or silex, we may presume that the 
 great mass of the sun consists of silicon and oxygen 
 uncombined, because all substances in the sun are heated 
 up to and beyond the point of chemical dissociation. 
 
 This elementary substance has never been fused by 
 any heat that can be produced on the earth or concen- 
 trated from the sun ; and if any substance could remain 
 unmelted in the sun, it would probably be silicon. 
 
 We tind the earth to be finished off with an irregu- 
 lar veneering of carbon on or near its surface. This 
 location of the carbon on the earth is not accidental, 
 but results from the operation of natural laws. 
 
 All the carbon of the earth, probably not excepting 
 even the small portion existing in the form of the dia- 
 mond, has been drawn from the atmosphere by the 
 decomposition of carbon dioxide, or carbonic acid gas, 
 by the agency of sunlight acting through the vegetable 
 kingdom.* Of course, this carbon must be deposited on 
 or near the surface of the earth. For other reasons, 
 we may expect to find the carbon of the sun at his sur- 
 face as the dividing stratum between his nucleus and his 
 atmosphere proper. Though we meet with pure carbon 
 on the earth in several allotropic forms, we find it in 
 two conditions only as affected by heat, viz. : the solid 
 and the vaporous or volatilized ; never as a liquid nor 
 as a gas, unless volatilized carbon be gaseous. 
 
 One thing seems certain, that is, that the visible sub- 
 stance of the photosphere is apparently opaque, and 
 appears to us simply as the radiator of intense light 
 
 * Newton, for optical reasons, suspected the diamond to be of vegetable origin. 
 
 17 
 
258 
 
 SUN SPOTS. 
 
 and heat. Speaking of tilings of which we know little, 
 it may be said that probably all bodies must exist in a 
 gaseous or ultra gaseous form before separation can take 
 place into the ultimate particles. Also, that all particles, 
 even those of the most transparent gases, are solid 
 bodies, and that, in a highly incandescent condition, 
 they appear opaque, but glitteringly bright. Carbon in 
 this condition might appropriately be called diamond 
 dust, if we can conceive of dust of the fineness of the 
 ultimate particles of matter. 
 
 Still, it is not necessary for our purpose to suppose 
 that carbon exists in the photosphere in the form of gas. 
 It is more probable that it exists in the finely divided 
 form which we see in fames or in the electric arc. 
 
 I have seen in the cabinet of Prof. H. S. Carhart, in 
 the Northwestern University, and I presume there are 
 many such cases, an Edison lamp in which one arm of 
 the carbonized bamboo was ruptured and a portion of 
 the carbon volatilized. The carbon was deposited as a 
 fine dust all over the inner surface of the bulb, except 
 on a fine, straight, perpendicular line, exactly opposite 
 the remaining arm of the bamboo, showing conclu- 
 sively that the volatilized carbon radiated out in all 
 directions in straight lines, like light, except where it 
 was intercepted by an intervening obstacle. 
 
 This tends to show that volatilized carbon in a vacu- 
 um is not gaseous. If it were, it would have filled the 
 glass bulb and pressed equally on every part until 
 condensed by cooling. The same would have been 
 true if the carbon was in the form of vapor, as com- 
 monly understood. Therefore I incline to the opinion 
 that carbon, when not an ordinary solid, is in the form 
 of impalpable dust, and in that condition forms the 
 
INCANDESCENT CARBON VAPOR. 
 
 259 
 
 photosphere of the sun. However, as the photosphere 
 more nearly resembles the clouds of our sky than any 
 other form of matter we are familiar with, I shall con- 
 tinue to speak of it as composed of vapor, that is, car- 
 bon vapor. This impalpable dust is slightly denser 
 than the gases in which it floats, and dances in them 
 as freely as the motes in our atmosphere. Being slightly 
 denser, this carbon dust will seek the lower levels of the 
 sun’s atmosphere. 
 
 Like nearly all other forms of matter, the cooler por- 
 tions will be the densest and will form the lowest strata, 
 or rest upon the nucleus of the sun. In fact, it may 
 cover this nucleus for thousands of miles in depth, as 
 loosely deposited masses of incandescent impalpable 
 powder. If the sun receives and parts with his heat 
 at the surface, as I have supposed, the outer surface of 
 this jfliotosphere will always be the hottest and brightest 
 part of the sun, and the lower we descend in imagina- 
 tion through this vast enveloping cloud, the less highly 
 heated and the less brilliant it will be found. Although 
 it is not probable that the lowest and coolest part of 
 these clouds falls below a white heat, yet, in contrast 
 with the intensely heated and glittering brightness of 
 the surface, the lowest stratum of the photosphere will 
 appear entirely black. Whether or not this carbon 
 vapor or atomic dust assumes the liquid form on cooling 
 we may never know to a certainty. But even if it 
 does not, it doubtless undergoes changes analogous to 
 the condensation and falling to the earth of aqueous 
 vapors. When, therefore, sun spots occur, large areas, 
 sometimes amounting to millions and billions of square 
 miles, of this photosphere are cooled, condensed and 
 precipitated on the nucleus of the sun. These precipi- 
 
260 
 
 SUN SPOTS. 
 
 tated vapors at the nucleus will now be exposed to the 
 concentrated rays of the sunny concave. The revola- 
 tilization of the precipitated carbon will be resumed 
 and the cavity will ultimately be refilled with photo- 
 spheric carbon clouds. 
 
 The atmosphere in which these carbon vapors float 
 is composed largely of the gases of iron and other 
 metals. As in our atmosphere there is a certain 
 stratum in which the clouds float, so in the sun’s atmos- 
 phere there is a certain stratum whose density is ex- 
 actly adapted to the clouds forming the photosphere. 
 
 PROOFS. 
 
 As it has never yet been proved that carbon exists at 
 all in the sun, much less that his entire photosphere is 
 composed of this element, it is not to be expected that 
 this theory will meet with ready acceptance without 
 some considerations tending to show its probability at 
 least. I present the following : 
 
 1. Carbon exists in large quantities and in various 
 forms in the crust, on the surface and in the atmos- 
 phere of the earth, and in many of the meteorites 
 falling on the earth. Analogy would lead us to expect 
 its presence in some form in the sun. 
 
 2. Carbon is the source of nearly all the artificial 
 light and heat that exists on the face of the earth. It 
 warms and lights our dwellings, cooks our food, reduces 
 our ores, drives our factories and transports us from place 
 to place on sea and land. It figures at both ends of the. 
 electric light. At one end it drives the engine that 
 generates the electricity, and at the other gives out the 
 light by means of the carbon points. 
 
 3. In this last respect it most resembles the function 
 
PROOFS.' 
 
 261 
 
 of carbon in’ the sun. The electric light is by far the 
 nearest approach that has been produced on the earth 
 to the dazzling light of the sun, which it much resem- 
 bles. The particles of carbon as it may be supposed to 
 exist in the vapor or atomic dust of the photosphere, 
 certainly possess the peculiar quality of radiating light 
 and heat to a wonderful degree, and seem precisely 
 adapted to produce the effects which we observe in the 
 photosphere. 
 
 4. If we reject carbon from this position and func- 
 tion, with what material will we supply its place? 
 Neither the vapor of iron nor any other metal is avail- 
 able, because these metals are proved to be transpar- 
 ent gases in the stratum overlaying the photosphere, 
 whereas the latter is an aggregation of opaque fiery 
 clouds. Probably the only remaining substance that is 
 not volatilized and sent to the upper regions of the sun’s 
 atmosphere is silicon. But this has never exhibited any 
 of the light and heat producing properties of carbon, 
 and hence there is no reason for assigning it to this 
 place. 
 
 5. Nature always employs the means best adapted 
 to secure her ends. The photosphere ought to be and 
 is, above all other forms of matter, the greatest radiator 
 of light and heat. But a good radiator of heat must of 
 necessity be an equally good absorber. In both of 
 these respects, carbon is unequalled. But the sun can 
 only receive heat from without by radiation from other 
 suns. If the sun’s radiant heat came from within its 
 own body, not only would it speedily be exhausted, but 
 the photosphere, by means of which this heat is radi- 
 ated into sjrnce, would be the coldest and darkest part 
 
262 
 
 SUN SPOTS. 
 
 of the sun, instead of being the seat of his most intense 
 heat and light. 
 
 6. It may be inquired : If the whole photosphere is 
 glorified incandescent carbon, in fact, literal diamond 
 dust, why does it not show itself by means of the spec- 
 troscope ? I reply that the spectroscope gives but three 
 kinds of spectra : the continuous spectrum of incandes- 
 cent solids and liquids ; the bright-lined spectra of 
 incandescent gases, and the dark-lined spectra of absorb- 
 ing gases. The condition of carbon in the photosphere 
 being an opaque cloud, is such as to give out only the 
 continuous spectrum. This it does, but marked by the 
 absorption lines of the overlying gases of iron, sodium, 
 hydrogen, etc. Silicon is invisible in the sun for the 
 same reason. In tine, it is not a matter of reasoning, 
 but of fact, that the most refractory substance or sub- 
 stances, the last to fuse and vaporize, must form the 
 core of the sun. This, from the analogy of the earth, 
 we should infer to be mainly silicon. 
 
 But it may be said that as carbon volatilized in the 
 electric arc, and even in the Bessemer furnace, does 
 give out bright-lined spectra, why not in the sun, if it 
 exists there ? 
 
 It is a familiar fact that the more a gas is compressed 
 the more nearly its spectrum approaches the continu- 
 ous form. Hydrogen, the rarest of gases, may be so 
 compressed as to yield a continuous spectrum. 
 
 The compression under which carbon exists in the 
 photosphere may well be amply sufficient to overcome its 
 reluctant tendency to exhibit bright-lined spectra in the 
 spectroscope. If it be an argument against the carbonic 
 constitution of the photosphere that it gives no bright 
 lines in the spectroscope, it is an equally good objection 
 
TROOFS. 
 
 263 
 
 to every other known substance, as the photosphere, 
 whatever be its constitution, gives out no bright-lined 
 spectra, but the continuous spectrum only. 
 
 7. Carbon is sui generis among the elements. It 
 sparkles with an inherent light in the diamond. In the 
 forms of wood, charcoal, mineral coal and the hydro- 
 carbons, it burns readily and often with uncontrollable 
 intensity ; while in the form of graphite, it is one of 
 the most incombustible of the elements, and in all its 
 forms it is infusible at any degree of terrestrial heat. 
 But while infusible, it can readily be volatilized in the 
 electric arc. It seems to ignore the liquid state and 
 leap at one bound from the solid to a state nearly re- 
 sembling the gaseous. And still we cannot say that in 
 this condition it is a gas. On the contrary, it seems to 
 be simply fixed carbon, only infinitely subdivided and 
 shining with unutterable brightness. It is in this form, 
 as I conceive, that it forms the photosplieric clouds, 
 brightest and most rarefied at the surface, where it is 
 exposed to the concentrated starshine of all the suns, 
 and decreasing in brightness, but increasing in density 
 for thousands of miles downward to the nucleus of the 
 sun. 
 
 8. I need spend no time in proving that the photo- 
 sphere is not a transparent gas. Although it floats in an 
 atmosphere of metallic gases, its cloud-like character is 
 conceded by all. What element, except carbon, is capa- 
 ble of preserving a finely divided or even vaporous 
 form under a temperature that converts iron and other 
 metals into transparent gases ? 
 
 Lastly, in the economy of nature, the peculiar func- 
 tion of carbon seems to be the reception and radiation 
 of heat, while that of ether seems to be its rapid con- 
 
264 
 
 SUN SPOTS. 
 
 veyance from sun to sun and from world to world. On 
 the earth heat creeps, walks or runs according to the 
 conducting capacity of the different substances on 
 which it is dependent for transmission, but it flies 
 through space on ethereal wings at the rate of one hun- 
 dred and eighty-five thousand miles per second. 
 
CHAPTER YIII. 
 
 APPEARANCE OF SUN SPOTS. 
 
 Plicebi tristis imago 
 
 Lurida solicitis prcebebat lumina terris. 
 
 — Ovid. 
 
 W E will here introduce another figure from Schel- 
 len’s “ Spectrum Analysis,” illustrating the ap- 
 pearance of the sun spots : 
 
 Fig. 17.— Sun Spot of July 30, 1869. 
 
 This figure is most instructive. We can almost read 
 in it the whole history of a large sun spot. It has evi- 
 
 265 
 
266 
 
 SUN SPOTS. 
 
 dently been a spot of the size of the outer periphery of 
 the penumbra, but now in the process of healing up. 
 Granulations from all sides are pushing in toward the 
 centre, as if to close up a wound inflicted on the sun by 
 his own ungrateful children. 
 
 The enormous size of many of the sun spots is incon- 
 sistent with the idea that they are produced by the splash- 
 ing of falling meteors. Our earth, if dropped into some 
 of these cavities, would be like a pebble dropped into the 
 crater of a volcano. Bodies of that size could easily be 
 observed if such were falling into the sun. Besides, 
 their absence from the Armament would quickly ‘be 
 noted by our eagle-eyed astronomers. Still less can we 
 conceive of eruptions covering millions of square miles. 
 In fact the appearance of the spots resembles nothing 
 we can conceive of so much as the condensation and 
 precipitation of large areas of solar clouds in conse- 
 quence of changes in the solar weather, quite analogous 
 to what we see on the earth, where clouds covering large 
 districts frequently condense and disappear in a few 
 hours. The edges of these precipitated clouds would 
 naturally be grandly jagged like those of the silver- 
 capped thunder heads that sometimes adorn our sum- 
 mer skies, only incomparably vaster and brighter ; in 
 one word, like the edges of a sun cloud. 
 
 But a change of weather in the sun, as upon the 
 earth, means a change in temperature. Our changes 
 come from the sun. The sun’s changes must come from 
 other heavenly bodies. The sun, vast as is his mass, can 
 no more originate changes in his own temperature or 
 weather than the earth. If he were wholly isolated 
 from all extra-solar influences, his own heat would very 
 soon be equally diffused throughout his entire mass, and 
 
APPEARANCE OF SUN SPOTS. 
 
 267 
 
 all activity would cease. It is only by interaction and 
 interchange among celestial bodies that the eternal 
 round is kept up, which forms the life of the world. 
 
 The edges of these sun spots, thousands of miles in 
 depth, sometimes take on the appearance of cyclones 
 produced by the clashing currents in the photospheric 
 clouds, as elsewhere explained. Generally, however, as 
 the sun’s heat arrives and departs from all parts of his 
 surface almost equally, the clouds will be comparatively 
 calm, and a sun spot, once formed, will be likely to 
 remain for a considerable time. The wreathen vapors 
 around the edges and projecting into the abyss seem to 
 take on the fantastic forms of beauty with which nature 
 delights to amuse herself in her idle hours, more akin 
 to cumulus clouds, lazily sunning themselves in our calm 
 summer skies, than to the rude shocks of storm and 
 tempest. The fringes, plumes and sprays that charac 1 
 acterize some of the sun spots, resembling the arbores- 
 cent and fern-like tracings of frost work upon glass, are 
 finely delineated in another of Prof. S. P. Langley’s illus- 
 trations. This, on account of its size, we are obliged to 
 divide. The other half will be introduced as Fig. 21. 
 
 Another peculiar appearance in the sun spots may 
 perhaps be explained upon this theory. I refer to the 
 grandly corrugated or channelled appearance of the 
 sides, as if raked downward by Neptune’s trident. If 
 the body of the spots, so to speak, is produced by con- 
 densations of great areas of fiery clouds, then we may 
 suppose that the edges of these spots are in a condition 
 of partial condensation, and therefore denser than the 
 surrounding photospheric clouds. These partially con- 
 densed bordering clouds might be expected to roll or 
 glide down the declivities of the sun spots, and the pe- 
 
268 
 
 SUN SPOTS. 
 
 culiar manner in which the snn is supposed to receive 
 his light, not in parallel rays as from one sun, but in all 
 directions, would show these avalanches as bright at the 
 bottom as at the top. 
 
 Again ; these vast descending avalanches of partially 
 
 Fig. 18.— Sun Spot of March 5, 1873.— By Prof. S. P. Langley. 
 
 cooled solar clouds would, on reaching the nucleus, be 
 arrested and swell out or bulge into those club-shaped 
 forms observed at the bottom of the sun spots; and, 
 moving horizontally toward the centre, they would ulti- 
 mately cover the bottom and completely fill up the cav- 
 
BOILING APPEARANCE OF SUN SPOTS. 
 
 269 
 
 ity. Owing to the rounded or club form of these ava- 
 lanches at the bottom, and the cross fire of the light by 
 which they are seen, they will appear highly luminous, 
 especially so by contrast, so long as any portion of the 
 floor remains uncovered. 
 
 BOILING APPEARANCE OF SUN SPOTS. 
 
 Anyone who has watched what is called the boiling 
 action at the bottom of these spots must have the most 
 intense interest and curiosity awakened to know the 
 cause of this most interesting phenomenon. 
 
 The boiling appearance harmonizes admirably with 
 the theory here advanced. If the photosphere is com- 
 posed of intensely heated carbon dust or mist, and the 
 spots are immense openings in the same, caused by the 
 partial cooling and condensation of this substance, then 
 this condensed and precipitated material will be much 
 darker, .as well as cooler, than the surrounding photo- 
 sphere. In fact, in comparison with the photosphere, 
 the spots appear perfectly black. This darker precijDi- 
 tated matter covering the umbra or nucleus, is immedi- 
 ately exposed to the starshine of the heavens. It will 
 gradually reabsorb heat, and w T ill almost literally boil 
 up from the bottom. This process will continue till this 
 matter has attained the temperature of the surrounding 
 photosphere and filled the cavity with the newly formed 
 clouds. The process is slightly analogous to what we 
 sometimes witness upon the earth when the whole heav- 
 ens are covered by thick layers of cloud. These, by 
 cooling, condense to rain and fall to the ground, cover- 
 ing its surface with a plentiful moisture. Then comes 
 out a hot sun and vaporizes this moisture, and in a short 
 time the sky is again covered with fleecy clouds. This 
 
270 
 
 SUN SPOTS. 
 
 boiling action of the sun spots, like a boiling pot, com- 
 mences at the edges or penumbra where the photo- 
 spheric clouds have been only partially cooled, and there- 
 fore soonest recover the normal temperature of the 
 photosphere. 
 
 FACUL^E. 
 
 I desire to notice only one more of the phenomena 
 attending sun spots, and that is the faculae or bright 
 ridges that frequently surround the spots. These, by 
 some of the advocates of the eruptive theory are 
 ascribed to the splashing upward of the photospheric 
 material by the downpour of the cool eruptions. 
 
 There are at least three objections to this view. One 
 is, that it is inconceivable that a single eruption could 
 be of such enormous dimensions as some of these spots 
 present. Another is, that explosive eruptions of such 
 extent and violence, if they existed, would tear up the 
 photosphere in the wildest and most disordered forms, 
 instead of the gently sloping and channelled edges of 
 the penumbra, with its arborescent sprays and fern-like 
 fringes. Lastly, and most conclusively, if these spots 
 were caused by explosive eruptions, the ejected matter 
 would fall back almost as soon as expelled, and the sea 
 of fire would close over the crater as quickly as if it 
 were water on the earth. If, on the contrary, these 
 spots, continental in their dimensions, are caused by 
 climatic changes, which even on the earth often extend 
 through many days, we may reasonably expect the same 
 to occur in the sun. Such we find to be the fact. 
 
 Now, on this hypothesis, we should expect the upper 
 edges, or the margins of the sun spots, to be much 
 brighter than the general surface of the photosphere, 
 
FACULAS. 
 
 271 
 
 just as the umbo or highest point of a rounded gilt 
 button is always dazzlingly bright, while the rest is 
 relatively dull. So the edges of the deep cavity caused 
 by cooling, condensation, and precipitation, must neces- 
 sarily stand out more prominently in consequence of 
 the caving in, so to speak, of the sun spot. These 
 edges, thus left prominent, may account for the faculee 
 around the spots. This is grandly illustrated in the 
 edges of the magnificent summer clouds that form the 
 rocky mountains of our western skies. This feature is 
 well illustrated by Fig. 19. 
 
 Fig. 19 .— From Schellen's “Spectrum Analysis.” 
 
 But not infrequently spots appear surrounded by 
 literal mountains of light. This is just what might be 
 expected on the theory here advocated. A valley in 
 an Alpine region of the sun is unlike a valley similarly 
 situated on the earth. In the latter case the valley will 
 be hotter than the surrounding mountains. It will 
 receive just the same amount of heat by radiation, both 
 the mountain and the valley being shaded on one side 
 when the sun’s rays are oblique, and both receiving his 
 full radiance when the rays are vertical. But in the 
 case of the terrestrial mountain, the beat is reflected 
 
272 
 
 SUN SPOTS. 
 
 away, while in the case of the valley, it is reflected from 
 side to side, and nearly all retained. 
 
 In the sun the valleys are coolest, because the star- 
 shine comes in all directions, and much of it being 
 received on the sides and summits of the towering 
 faculae, is cut off from the valleys between, which are 
 therefore relatively cooler than the rest of the photo- 
 sphere, and therefore more likely to become the thea- 
 tres of sun-spot action. 
 
 Fig. 20.— Faculae and Sun Spots, by Chacernce. 
 
 This is illustrated by Fig. 20, from Scliellen’s “ Spec- 
 trum Analysis.” 
 
 GRANULES AND PORES. 
 
 One of the most convincing arguments of the truth 
 of this theory of sun spots to the mind of the writer, 
 may be stated thus : 
 
 Those who have examined the solar surface most 
 
GRANULES AND PORES. 
 
 273 
 
 carefully, with the best facilities, and under the most 
 favorable circumstances, find that the surface, though 
 we seek in vain for words to express its intensity of 
 light and heat, is not of uniform brightness. It is 
 mainly made up of what are called granules and pores, 
 or alternate specks of light and shade, though even 
 these granules are often 100 miles in diameter, and the 
 pores much larger. These granules and pores resemble 
 rice grains floating in a lake of ink ; or, perhaps, a 
 better illustration would be a western landscape, seen 
 at a little distance, at the moment when the first snow 
 flakes of winter have scarcely half covered the black 
 soil of our prairies. According to the law which makes 
 brightness proportioned to heat in a radiant body, the 
 granules represent the most highly heated, and the 
 pores the relatively cooler, portions of the photosphere. 
 In other words, the granules are little faculse, and the 
 pores little sun spots. These granules and pores are 
 coextensive with the sun’s surface, and are not confined 
 to the maculated zones. These pores are caused, as I 
 believe, by the enormous amount of heat constantly 
 radiated by the sun, which cannot fail to lower rapidly 
 the temperature of the solar surface. If the sun re- 
 ceived no increments of heat at his surface, his whole 
 face would speedily turn to blackness. He could not 
 wait for heat to be supplied by the slow processes of 
 conduction or convection from an inexhaustible foun- 
 tain at his centre, even if we conceded its existence. 
 But it would be just as impossible to manufacture heat 
 from nothing at the centre of the sun as to manufacture 
 matter in the same way. Instantaneous radiation 
 requires an instantaneous supply. An infinite amount 
 sent forth demands an infinite amount returned, and 
 18 
 
274 
 
 SUN SPOTS. 
 
 the rapidity of one operation precisely measures that 
 of the other. 
 
 If these pores are little sun spots caused by cooling 
 and precipitation by radiation from small areas of the 
 photosphere, we have only to suppose this cooling to be 
 slightly increased from any cause in the maculated 
 belts to account for the enlarged areas of cooling and 
 precipitation called sun spots. 
 
 I need not say where I would look for this cause, 
 to- wit : to the shadows cast by Jupiter and the lesser 
 planets upon the sun. 
 
 This theory also accords beautifully with the small 
 beginnings, slow growth, and long duration of sun 
 spots. Janies Carpenter says: “The first symptom of 
 a spot appearing is a tiny speck upon the photosphere. 
 This goes on enlarging,” etc. Such a beginning and 
 evolution are compatible with neither a meteoric nor 
 an eruptive cause. If they were produced by the 
 splashing of bodies of the size of the earth, or even 
 Jupiter (for the diameters of some of these spots far 
 exceed that of Jupiter), they would not commence at 
 a point and gradually enlarge. Neither would they 
 continue for weeks and months with only slight changes 
 in form and size. 
 
 This argument is equally good as against the erup- 
 tive theory, and seems to be conclusive against both. 
 A gaseous eruption would burst forth with suddenness 
 and violence, of full dimensions, and the displaced pho- 
 tosphere would fall back to its place as soon as the 
 eruption ceased. 
 
 The writer would not, of course, deny the existence 
 of immense eruptions in the sun. But these are mainly 
 in the chromosphere, corona, and upper atmosphere. 
 
GRANULES AND PORES. 
 
 275 
 
 Eruptions in the photosphere, so far as he can learn, are 
 hypothetical only. 
 
 The point to which the writer desires to call the atten- 
 tion of those who are in search of truth for its own 
 sake, is this, that the spots commence in points, and 
 open out more or less gradually, often to continental 
 dimensions, which they sometimes retain for months. 
 
 Fig. 21.— Sun Spot of March 5, 1873.— By Prof. S. P. Langley. 
 
 We here introduce the other half of one of Prof. 
 Langley’s illustrations, both for the purpose of showing 
 the club-shaped projections into the cavity and the 
 
276 
 
 SUN SPOTS. 
 
 relative size of one of these spots compared with the 
 Western Hemisphere of the earth, shown in the upper 
 left-hand corner. If the original spot, as seems to me 
 probable, was co-extensive with the outer edge of the 
 penumbra, it will be seen at a glance how improbable 
 it would be that the spot could be caused by either a 
 meteor or an eruption. If the meteor were of the size 
 of the earth, it would be lost in the cavernous depth of 
 one of these spots. 
 
 Neither a meteor of sufficient size, nor an eruption 
 of sufficient extent, to produce such a spot, could com- 
 mence with a point and enlarge to billions or even mill- 
 ions of scpiare miles. But if the photosphere through- 
 out its whole extent and in its normal condition is 
 honeycombed with little sun spots, caused by the cool- 
 ing from radiation, then it needs but a slight additional 
 cooling in the maculated belts to cause first the coales- 
 cence of a few neighboring spots and then their exten- 
 sion to large areas. 
 
 The theory of sun spots here advanced also harmon- 
 izes with one of nature’s sublimities ; the sublimity of 
 the minute. Nature is sublime in the smallness of her 
 atoms ; in the minuteness of her microscopic and ultra 
 microscopic organisms, and often in the feebleness of 
 her forces. The force of gravitation acting on the 
 earth is so weak that it only pushes the earth about one- 
 tenth of an inch toward the sun, while the tangential 
 force carries it nearly nineteen miles forward. But 
 the cooling shadows that cause the sun spots are the 
 exact counterpart of gravitation on the earth. This 
 shows how small a change is required to enlarge the 
 small spots or pores into the larger ones. It also shows 
 why the maculated belts are almost never free from 
 
GRANULES AND PORES. 
 
 277 
 
 spots, because the planets even at their aphelia cast 
 slightly cooling shadows on the sun. If the breaking out 
 of these spots be attributable to a lowering of the tem- 
 perature in the maculated belts, and I do not see how it 
 is possible to doubt it, in view of their darker color and 
 lower temperature, then it is manifest that the photo- 
 sphere within those belts, notwithstanding its intense 
 heat, is at the turning point, so to speak, between the 
 condition of the bright granules and the darker pores, 
 with the advantage rather on the side of the pores. 
 These, according to Prof. Langley, occupy four-fifths of 
 the sun’s surface, but emit only one-fourth of his light 
 and heat. 
 
CHAPTEK IX. 
 
 RECAPITULATION. 
 
 Line upon line, precept upon precept. — Bible. 
 
 ^IRST. It is a matter of fact and not of conjecture 
 
 J-J that Jupiter and the other planets intercept and 
 shut off from the sun a portion of the light from a large 
 field of the starry concave. If the stars send forth rays 
 of energy capable of being turned to heat at the sur- 
 face of the sun, then the sun will be deprived of so 
 much heat as represents the intercepted rays of me- 
 chanical motion convertible into heat. 
 
 2. The sun’s photosphere is generally believed to 
 be composed of incandescent metallic vapors (I have 
 suggested carbon vapors), floating in an atmosphere of 
 metallic gases. 
 
 3. It is by much the hottest portion of the sun. This 
 is shown first, by actual experiment by Prof. Langley 
 and others ; second, by its surpassing brilliancy, the tem- 
 perature of elementary substances being invariably in 
 proportion to their brightness or capacity for emitting 
 light ; and third, by analogy of other celestial bodies ; 
 e.y ., the Earth and other planets, especially Jupiter, 
 exhibit unmistakable evidence of a common origin and 
 nature with the sun.' These all receive and part with 
 their commercial or exchangeable heat at their ports of 
 entry. These ports embrace their whole exterior sur- 
 face in contact with the ethereal ocean, by means of 
 
 278 
 
RECAPITULATION. 
 
 279 
 
 which the imports and exports of their foreign com- 
 merce in the different forms of energy are exchanged. 
 The sun is the great entrepot of this commerce in our 
 system where, as I think, mechanical motion is ex- 
 changed for liglit and heat, the fixed capital or internal 
 heat of all these bodies remaining unchanged from age 
 to age. 
 
 4. As the sun’s photosphere is hotter than the nu- 
 cleus, it cannot, either by conduction or convection, 
 receive this excess from the interior, and consequently 
 must receive it through the ether from the starry con- 
 cave. 
 
 5. Jupiter and the other planets are the only bodies 
 which can possibly intercept the energy convertible 
 into heat, coming from the celestial concave. 
 
 6. These shadows are wholly penumbra! and exceed- 
 ingly thin, as the light and heat from almost the entire 
 starry concave shines over, under and around the 
 planets. Still these shadows are not infinitesimal in 
 their influence. It is easy to see without a diagram 
 that a portion of the wave motion, or energy converti- 
 ble into heat, from a large circle in the starry vault is 
 intercepted from the sun by each of the planets. 
 
 7. The inclination of the sun’s equator to the 
 ecliptic, by increasing the extreme solar latitude north 
 and south, of all the planets, widens the shaded or 
 maculated zones. This can be readily seen from Fig. 
 15. The central part part of this zone on both sides of 
 the equator is given up as the arena for the perpetual 
 battle of the giants in the form of photospheric clouds 
 from both the north and south, where they meet in con- 
 flict, and the ranks of both sink vanquished to unknown 
 depths below. In the melee of this conflict the clouds 
 
280 
 
 SUN SPOTS. 
 
 are too much agitated to admit of the formation of sun 
 spots, as these require a comparatively undisturbed con- 
 dition of the photosphere in which they can slowly 
 develop and retain their forms, sometimes for months, 
 with only slight changes. The necessary result will he 
 two u spotty ” belts, which we might almost predict a 
 priori would be found mainly between the parallels of 
 ten degrees and thirty degrees of north and south lati- 
 tude. 
 
 This corresponds wonderfully with the distribution of 
 the sun spots. 
 
 8. Sun spots must of necessity be produced by some 
 dynamic change, and doubtless of that form which we 
 call heat. In other words, by an excess or deficiency of 
 heat. If it were an excess, the photospheric clouds in 
 these belts would become brighter, if that were possible. 
 But, as the spots appear to dissolve and turn to black- 
 ness, it must be a deficiency, instead of a redundancy, 
 of heat which produces the spots. 
 
 9. To the shadows of the planets alone can we 
 look for this cooling influence upon the maculated zones 
 of the sun. There are no other intervening bodies. 
 
 10. As all the forms of cosmic energy are correlated 
 and interchangeable ; and as a portion of this energy, 
 exactly proportioned to the mass of each planet 
 divided by the square of its distance, is intercepted from 
 the sun and expends itself upon the planets themselves, 
 and as this is the exact expression for gravitation, who 
 can doubt that the intercepted energy is identical with 
 gravitation and constitutes the centripetal forces of all 
 the planets ? 
 
 11. The sun spots appear to have a certain degree 
 of periodicity, but not sharply defined, either as to the 
 
RECAPITULATION. 
 
 281 
 
 amount of variation or the times of the apparent max- 
 imum and minimum periods. The variations in these 
 spots are much like the vicissitudes of the weather on 
 our earth, and produced by similar causes. The seasons 
 return with certainty, but variable as to the degrees of 
 heat and cold, and also in being earlier or later within 
 certain limits. The grand average, however, is always 
 the same. It is the same with the sun spots. The aver- 
 age for a long series is very nearly uniform, being 
 nearly, if not exactly, 11.86 years, which is the period 
 of Jupiter’s annual revolution from perihelion to 
 perihelion. Now Jupiter’s mass is three hundred and 
 thirty-eight times that of the earth, and more than 
 double that of all the other planets combined. His 
 mean distance from the sun is much less than the mean 
 of the other major planets. His eccentricity is such that, 
 at his perihelion, he is forty-five million miles nearer to 
 the sun than at his aphelion. The effect of this combi- 
 nation of facts is such that the planet Jupiter, if the 
 theory of sun spots here advanced is correct, must dom- 
 inate both as to the amount and the periodicity of the 
 spots, although the other planets sometimes co-operate 
 with, and at others antagonize, his influence, so far as 
 the dates of the maximum and minimum periods are 
 concerned ; and this fact contributes to the aj:>parent 
 irregularity in the periodicity of the sun spots. 
 
 12. The heating of the air at the equator and cool- 
 ing it at the poles of the earth cause a constant circula- 
 tion of currents from the equator toward the poles and 
 back. These currents, however, are regular only in 
 their irregularity. The exceptions almost constitute the 
 rule in the case of the terrestrial currents, owing to the 
 variations in isothermal lines upon the earth, the differ- 
 
282 
 
 SUN SPOTS. 
 
 ence in temperature of continents and oceans, the differ- 
 ence in friction between land and water, and other 
 causes existing on the earth which do not exist in the 
 sun. 
 
 If the sun’s photosphere is slightly cooler at or near 
 the equator than at his poles, it will cause a correspond- 
 ing system of slow and gentle currents toward the poles 
 and back again, but in reverse order, compared with the 
 terrestrial currents. The lower currents will be the 
 cooler and the upper ones the hotter. The lower ones 
 will be accelerated relatively to the sun’s surface in pro- 
 portion as they recede from the equator. The upper 
 ones, on the contrary, will be retarded relatively to the 
 sun’s surface in proportion to their distance north and 
 south of the equator. The inevitable result of this will 
 be that spots or openings in the upper photosphere will 
 keep pace with the rotary motion of the sun at his 
 equator, but will drag behind more and more as they 
 increase in latitude, precisely as we find the fact to be. 
 
 It is due to the writer also to remember that no claim 
 is here set up to anything like absolute regularity of 
 operation in these hypothetical photospheric currents. 
 A resemblance in the principle is all that is claimed. 
 
 13. In analogy with our seasons, the maximum of 
 sun spots almost always occurs after the sun has been 
 for some time exposed to the cooling influence of Jupi- 
 ter’s most effective shadows. 
 
 The planet Jupiter has been mentioned in connec- 
 tion with sun spots by almost every writer on the 
 subject, but only to discredit the idea that he could 
 exert any agency in producing them ; and the idea 
 that he, with the other planets, produces these spots by 
 
RECAPITULATION. 
 
 283 
 
 casting cooling shadows upon the sun is, so far as I am 
 aware, a novel one. 
 
 From all these facts and coincidences and the rea- 
 soning by which they are connected, I trust I have 
 made a case worthy of consideration of the distin- 
 guished men * of our day who hold the keys of knowl- 
 edge. That they will give it a candid and impartial 
 consideration I know, and to the decisions of exact sci- 
 ence I will bow with submission. 
 
CHAPTER X. 
 
 UNITY OF THE PROPOSITIONS CONCERNING SOLAR 
 HEAT, GRAVITATION, AND SUN SPOTS. 
 
 Have you not heard it said full oft’?— Shakespeare. 
 
 I DESIRE to repeat for the sake of emphasis, the 
 proposition that the photosphere is by far the hot- 
 test part of the sun. This proposition, if my argument 
 is sound, is sustained by two infallible proofs. 
 
 1. The ineffable and incomparable brightness of the 
 photosphere, which is the unfailing index of ineffable 
 and incomparable heat. 
 
 2. The actual and accurate determinations of Prof. 
 Langley and others, which no one questions, showing 
 that the photosphere is nearly twice as hot as the 
 umbra or nucleus of the sun. 
 
 This being conceded, all the main conclusions herein 
 advocated follow almost inevitably. For example : 
 
 1. The celestial source of solar heat seems absolutely 
 certain. The photosphere, notwithstanding its cooling 
 by radiation, being nearly twice as hot as the interior, 
 certainly cannot derive its heat from this interior. It 
 must therefore come from without, that is, from the 
 celestial concave. 
 
 2. It is almost equally certain that gravitation is 
 cosmic in its source, having its origin in propulsive 
 mechanical vibrations from the stellar concave. The 
 mutual interception of such rays is apparently the only 
 
 284 
 
UNITY OF THE PROPOSITIONS. 
 
 285 
 
 possible mode in which lines of least resistance can be 
 established and maintained in the heavens. The sun 
 shuts off a part of these rays from the earth and the 
 earth from the sun, making a line of least resistance for 
 both, in which each seeks to approach the other. But 
 all forces with which we are familiar, manifest them- 
 selves by motion in the direction of the least resistance, 
 and doubtless gravitation does the same. The motions 
 of the earth, both rotary and translatory, date back to 
 the eddies and swirls of primeval nebular matter. The 
 sun and earth are not tied together by a strong cable 
 attached to each, but rather, speaking figuratively, by 
 two invisible * hands, gently pressing them together. 
 These invisible hands are the invisible pulsations of the 
 invisible ether, with which the whole heavens are tilled, 
 coming from opposite points of the starry dome. The 
 sun intercepts from each molecule in the earth as many 
 of these pulsations or rays of mechanical force as there 
 are molecules in the sun, not one more nor less. The 
 earth does the same thing by the sun, so that in each 
 case gravitation is represented by the product of the 
 masses of each divided by the scpiare of the distance, 
 and the two bodies present, each to the other, a line of 
 motion in the direction of the least resistance in which 
 they will seek to approach each other, but balanced and 
 modified by other motions in other lines. 
 
 3. Lastly, sun spots being cooler than the photo- 
 sphere, and the heat of the latter coming down from the 
 solar sky in all directions, it would seem that the spots 
 must certainly result from the interception from the 
 maculated belts of a part of this fiery downpour.* But 
 
 * It must always be borne in mind that, according to the theory here advo- 
 cated, the incoming waves are, as Prof. Daniels shows, in the form of mechan- 
 ical force until they are arrested by the sun and turn to waves of heat. 
 
286 
 
 SUN SPOTS. 
 
 the only screens interposed between these belts and the 
 celestial sources of solar heat, are the planets and satel- 
 lites of the solar system. Each of these three grand 
 propositions throws light upon and confirms the others. 
 
CHAPTER XI. 
 
 IF. 
 
 Much virtue in an if . — Shakespeare. 
 
 I F the photosphere, which is the only portion of the sun 
 ordinarily visible to us, except the glimpses of the 
 nucleus which we sometimes catch through the sun-spot 
 openings, were simply a luminous, cloud-like envelope, 
 without proper motion of its own, it would most cer- 
 tainly accommodate itself to the motion of the nucleus 
 and move with it throughout its entire surface, and all 
 the sun spots would just as certainly keep pace with the 
 motion of the nucleus. 
 
 If there is a continual downpour of the upper sur- 
 face of the photospheric envelope from the poles toward 
 the equator, this upper surface, having the slow rotary 
 motion of the poles at its commencement, will inevita- 
 bly drag behind just in proportion to its distance from 
 the equator. 
 
 If such currents are actually approaching the equator 
 from the poles in the upper portion of the sun’s cloudy 
 envelope, then of necessity there must be counter-cur- 
 rents of the under portion correspondingly accelerated 
 on leaving the equatorial regions. 
 
 If this circulation exists, and I do not see how it can 
 be doubted, in view of the lagging motion of the sun 
 spots, then there certainly is a cooling process going on 
 in the equatorial regions of the photosphere. On no 
 other supposition can we account for this circulation. 
 
288 
 
 SUN SPOTS. 
 
 If there is such a cooling process going on in this 
 region, it must have a cause. 
 
 If the heat radiated by the sun is received, as ours 
 is, by ethereal undulations, and I have endeavored to 
 show that there is no other possible source, then this 
 cooling of the photosphere can only be effected by inter- 
 cepting a portion of these undulations. But certainly 
 there are no heavenly bodies interposed between our 
 sun and the stellar concave, except the planets and sat- 
 ellites of our system. What a wonderful confirmation 
 of this view we find in the fact that this cooling pro- 
 cess takes place right under the belt of the heavens in 
 which all the planets revolve! 
 
 I have introduced each of these propositions by an if. 
 But they are all facts, with many more, tending to the 
 same result, and I believe they all fit and dovetail to- 
 gether in such a manner as will, on full examination, 
 carry conviction to every candid mind. For example: 
 The sun spots are facts ; their periodicity corresponding 
 closely, if not exactly, to the Jovian period is a fact; 
 their location under a belt in the heavens including the 
 zodiac is a fact ; their lagging motion as they recede 
 from the equator is a fact ; their occasional cyclonic 
 action is a fact; their cavernous form and blackened 
 floor, indicating lower temperature, are facts, as well as 
 Langley’s actual measurements confirming the same ; 
 the location of all the planets and satellites in, or near, 
 the belt of the zodiac, is a fact; the inclination of the 
 sun’s axis to the plane of the ecliptic, bringing the mac- 
 ulated belts of the sun more directly under the planets, 
 is a fact ; the circulation in the upper and lower strata 
 of the photospheric and umbral clouds I fully believe I 
 am justified in pronouncing to be a fact, in view of the 
 
IF. 
 
 289 
 
 lagging motion of the spots, which cannot otherwise be 
 explained. It follows that the maculated belts are and 
 must be relatively cooler than the rest of the photo- 
 sphere. 
 
 Again, it follows with the certainty, as it seems to 
 me, of demonstration, that the sun spots are caused by 
 the condensation and precipitation of the photospheric 
 clouds. And lastly, if I am right, it follows with the 
 cumulative force of all these facts combined, that the 
 sun receives his unwasting supplies of light and heat 
 by ethereal undulations at his surface from the hollow 
 sphere of suns by which he is surrounded. 
 
 No imagination can possibly form a conception of 
 the Tophet of fire and flame that encircles the sun. It 
 has no resemblance to the lurid flames of Tartarus, as 
 painted by heathen poets. It is simply brightness and 
 heat in their most intensified forms. The energy or 
 ethereal motion, which causes the sun’s heat, may, and 
 probably does, come down as calmly and noiselessly as 
 our sunshine, or even starshine. It is not until these 
 ethereal vibrations bury themselves, so to speak, in the 
 sun’s photosphere that they turn to heat and are radi- 
 ated in that form. 
 
 19 
 
 
 t 
 
CHAPTER XII. 
 
 CONCLUSION. 
 
 Let us hear the conclusion of the whole matter. — Solomon. 
 
 ITHOUT intending it, and in spite of myself, 
 
 V V my thoughts have taken the form of a scheme 
 or system. I started out to commit to writing a few 
 thoughts in regard to solar heat. But I found that 
 this was but a single link in an endless chain, and that 
 I could neither comprehend the subject myself nor 
 make it intelligible to others without following this 
 mysterious energy under all its Protean forms and 
 through the entire circle of its manifestations. 
 
 Notwithstanding the feeble and halting steps by 
 which I have endeavored to trace the exhibitions of 
 this energy in nature, the system itself is grand beyond 
 the powers of thought or expression. 
 
 Of course the fundamental principle of the only true 
 system is the “ conservation of energy.” But many 
 writers, with whom I would not for a moment presume 
 to compare myself, at least for research in special 
 departments, seem to understand this principle in an 
 exceedingly limited sense. For example, it is not 
 uncommon for them to speak of all the heat of the sun, 
 except the two hundred and thirty millionth part, inter- 
 cepted and utilized by the planets, as wandering off 
 into the depths of space and being lost, forgetting that 
 heat and all forms of energy are motion, or at least 
 
 290 
 
CONCLUSION. 
 
 291 
 
 manifest themselves by motion. In the case of intense 
 heat, it is a rapid vibratory motion of incandescent 
 matter. But certainly there can be no motion where 
 there is no matter. If the ethereal waves should ever 
 arrive at a point where there is no ether to carry them 
 farther and no material bodies to arrest them, it is not 
 pretended that they could longer exist in any form. 
 This would certainly be their Tarpeian rock, from which 
 they would leap from existence into annihilation. The 
 same fate would await the doctrine of the conservation 
 of energy. Again, this two hundred and thirty mill- 
 ionth part of the heat of the sun received by the earth 
 and other planets is again radiated into space as fast as 
 it is received, as the earth is not growing hotter. This 
 is surely not inconsiderable in amount. But it is wholly 
 disregarded by many, I may almost say, by all. Again, 
 the starry concave is studded with millions of millions, 
 yea billions of billions, of suns beyond the power of the 
 imagination to grasp or of figures to express. Appar- 
 ently only an infinitesimal quantity of heat reaches us 
 from these suns. Consequently all the heat of the stars 
 is ignored so far as our system is concerned. Again, 
 gravitation is as universal as light and heat ; is as really 
 a form of working energy as the former ; is expended 
 and renewed as incessantly ; must have a source and a 
 destination, as much as light, heat or any other form of 
 energy; in other words, must form a link in an end- 
 less chain or an arc of a circle. In fact, it is not 
 expressing the truth too broadly to say that energy 
 never stands still. Yet so far as I know, no writer has 
 seriously undertaken to bring this great force in nature 
 into correlation with other forms of energy. 
 
292 
 
 SUN SPOTS. 
 
 The main propositions herein advanced and de- 
 fended are three : 
 
 1. That the universal ether is still the abode, though 
 in diversified forms, of the whole sum total of all the 
 energy with which it was replete in the nebular state, 
 when the heavens were aglow and “the elements dis- 
 solved with fervent heat.” This energy in varied 
 forms, however insensible, is to the last iota still extant, 
 or else conservation has failed to conserve. It leaves 
 the suns as heat, but during long progresses through 
 space turns to mechanical force and other forms of 
 energy, only to reappear as heat in the solar orbs ad 
 eternum ; perhaps by electrical vibrations of atomic 
 diamond dust in the photosphere ; perhaps simply by 
 arrested mechanical motion ; perhaps by a change in 
 vibration analogous to the sympathetic motion which 
 one vibrating body awakens in another. In fact, every 
 metamorphosis of energy is the arrest of one kind of 
 motion and the inauguration of another. 
 
 2. That this same energy in the form of mechanical 
 motion pervades all space, moving in right lines and 
 attacking every molecule and every mass equally on 
 every side, except where intercepted by one molecule 
 or mass from others. The nearer the intercepting 
 bodies are to each other, the more rays of force they 
 will intercept from each other in the proportion of the 
 inverse squares of the distances, thus marking lines of 
 least resistance in which all the bodies will infallibly 
 seek to approach each other. All will recognize this as 
 gravitation. 
 
 3. The planets, satellites and planetoids, revolving 
 around the sun within or near the belt of the Zodiac, 
 must and do intercept from the sun’s equatorial regions 
 
CONCLUSION'. 
 
 293 
 
 a portion of the emanations of a wide belt of the 
 heavens. All will admit that these emanations, how- 
 ever feeble, or however puissant, are in the form of 
 motion or energy convertible into heat. These inter- 
 ceptions or shadows must lower, however slightly, the 
 temperature of the equatorial regions of the sun, and 
 hence condensation and precipitation of portions of the 
 photospheric clouds, exhibiting the phenomena of sun 
 spots. 
 
 This trinity, inexpressibly grand, infinitely compre- 
 hensive, comprises a cycle so vast as to include the 
 light and heat of every sun and every known form of 
 energy. 
 

 4 
 
 *