CHAPTER IV.

CHAPTER IV.THE SOURCE OF SOLAR ENERGY.The remarkable resemblance between the mode of operation and effects of these electrical induction machines and the vast rotating electrosphere of the earth must be at once apparent. The operation is precisely the same, and the results must,pari passu, be substantially similar. We need not seek for precise parallelism of structure, because these machines themselves, it has been shown, widely differ in structure among themselves. But the almost infinitely more vast terrestrial electrosphere, which cannot be less than ten thousand miles in diameter, and perhaps much more (if we may form an opinion from the relative magnitude of the field of action of the hydrogen envelope which constitutes the solar electrosphere), rotating in the attenuated vapors of space, among which vapors that of water plays a most important part, and which vapors constantly impinge with various disturbances of contact against the more and more attenuated layers of the terrestrial atmosphere, and which gradually, from within outward, less and less partakes of the earth’s rotation until, finally, its rotatory movement is lost in the vast ocean of space, establishes the certainty that enormous quantities of electricity must there be disengaged, preciselyas in the machines which we have described, and to learn the potential or active pressure of this electricity we have only to consider the fact that we find a rise so rapid, as we ascend through our atmosphere, that the potential increases by from twenty to forty volts for each foot. That these currents are transmitted to the sun without appreciable resistance we already know, and that they are there transformed into light and heat we can, from the previously cited experiments, see.But it may be urged that the resistance of such attenuated vapors in space, and the generation of electricity in such quantities, would inevitably retard and finally destroy planetary motion. The sufficient answer to this is found in the consideration that the same facts must exist under any possible mode of organization of our solar system, and that such interference, besides, must have absolutely prevented its formation at all, if such were the case. All the matter of our planetary system together is only one seven-hundred-and-fiftieth that of the sun; if this were added to the sun’s bulk it would but slightly enlarge it. But all this solar and planetary matter together, if distributed over the space occupied by our planetary system,—and, by the nebular hypothesis of the organization of our solar system, this is requisite,—and having an axial diameter one-half that of its equatorial (see Proctor’s “Familiar Essays on Scientific Subjects,”—“Oxygen in the Sun”), would have had a density of only about one four-hundred-thousandth that of hydrogen gas at atmospheric pressure. This nebular mass musthave had a diameter at least sixty times that of the distance of the earth from the sun and a depth of thirty times its distance. That this enormous mass of attenuated matter should ever have been made to rotate as a whole by any force of attraction, repulsion, or rotation, with a tenuity so great that, if measured by an equal volume of hydrogen gas,—the lightest substance known to us,—it would have furnished material for four hundred thousand such systems as ours, presupposes a resistance so slight that the planets themselves, when coagulated out of such a mass, could never in any conceivable time exhibit retardation from such a source; and we know to a certainty that such attenuated vapors do exist in space, for electricity cannot be transmitted through a vacuum, and it is transmitted with perfect freedom between the earth and the sun. But it may be said that the laws were then different. If they were different then, they are doubtless different now. If, on the other hand, we assume that the bodies of which our solar system is composed were simply aggregated into concrete masses from meteoric dust, the difficulty is not lessened; for if the resistances to their operation now are such as to perceptibly retard their motions, they must have operated still more powerfully to originally prevent them; while, if hurled forth by an almighty fiat, complete from the hand of creative energy, the same force which impelled them forward must have also established the laws under which they now move.It is calculated that our earth must be losingtime, by tidal retardation, at the rate of one-half the moon’s diameter in each twelve hundred years (see Proctor, “Light Science for Leisure Hours,”—“Our Chief Timepiece Losing Time”), and that “the length of a day is now more by about one eighty-fourth part of a second than it was two thousand years ago.” Perhaps, however, we may discover that these changes are themselves periodic and increase in cycles to a maximum, and then diminish, as is the case with magnetic, planetary, and stellar variations, and other similar changes, when sufficiently long observed; for while such changes may very well accompany a theory under which our system and all other systems are slowly running down to decay and death, it is entirely incompatible with the primal forces under which theymusthave been originally formed. In other words, if the tides are dragging back our earth without compensation, this dragging back can only come from the oceanic deposit of water on the earth from the aqueous vapors of space which do not partake of the planetary rotation and orbital movement of the earth. But if these can now retard the earth’s motion, they must have originally prevented it in the beginning. This loss of time is, moreover, merely inferential from mathematical computations, and its basis is found in the belief that all the operations of nature are in a slow process of degradation, and the calculated loss itself may be merely theoretical, and not true in fact. Professor Proctor himself concedes the uncertainty of this alleged retardation when he says in the samearticle, “At this rate of change our day would merge into a lunar month in the course of thirty-six thousand millions of years. But after a while the change will take place more slowly, andsome trillion or so of yearswill elapse before the full change is effected.”While the processes of nature are generally believed to be running down, everything is bent to that belief; but the forces of nature must, nevertheless, be uniform and supreme, for it is by these forces that the expected results are to be achieved. That changes occur constantly is inevitable, but the source of these must be looked for in the interaction of original forces, and not in the degradation of systems. There is reason to believe, in fact, that the repulsion of the terrestrial electrosphere by that of the moon may itself be sufficient to counteract such retarding force of lunar gravity, for the tides upon earth are not merely oceanic, but atmospheric, and on the latter the electrical repulsion of the moon must act very powerfully and with directly counteractive effect.Planetary generation and transmission of electrical energy.—A, the planet; B, electrosphere showing circles of gradually diminishing rotation; E, interplanetary space; D, curve of gradually diminishing rotation; F, F, currents of electricity flowing to the sun; S, direction of the sun.Let us now apply the preceding principles to the problem under review. All planetary space is pervaded with attenuated vapors or gases, among which aqueous vapor occupies a leading place. The planets and all planetary bodies, having opposite electrical polarity from the central and relatively fixed sun, by their orbital motions around and constant subjection thereto act as enormous induction machines, which generate electricity from the ocean of attenuated aqueous vapor, each planet being surroundedby an enormous electrosphere, carried with the planet in its axial and orbital movements, the successive atmospheric envelopes gradually diminishing in rotational velocity until merged into the outer ocean of space. As the planets advance in their orbits they plunge into new and fresh fields, and, as the whole solar system gradually movesonward through space, these fields are never re-occupied. These electrospheres, by their rotation, generate enormous quantities of electricity at an extremely high potential,—so high that we can scarcely even conceive it,—and this electricity flows in a constant current to the sun, where it disappears as electricity, to reappear in the form of solar light and heat. These planetary currents also flow towards such other negatively electrified bodies as may exist in space—the comets and fixed stars, for example—in proportion to their distance; for, since resistance is not appreciable between ourselves and the sun, as is also the case with light, so, like light, our electricity must pass outward as well as inward to take part in the harmonious operations of the whole universe. But it should be noted that the distribution of electric energy in the form of currents is quite different from that of light or other radiant energy; for while light is diffused from a center outward through space, electric currents, on the contrary, are concentrated and directed along lines of force to concrete centers of opposite polarity. As a consequence, the intensity of light decreases according to the squares of the distances traversed plus the resistance to the passage of the light itself, while the electric current is only diminished by the resistance of the medium through which it passes. As the light of the sun has a velocity of one hundred and eighty-eight thousand miles per second, and the electric current between the earth and the sun the same, it will be seen that the resistance is practically alike for these two formsof energy. Indeed, the striking resemblance between the ethereal vibrations which constitute light and heat and exceedingly rapid alternating currents of electricity through molecular media may suggest that the transformation of one force into the other is some sort of a “step-up” or “step-down” process, much higher in degree, but of the same character as the well-known analogous electrical transformations used in the arts. It should also be borne in mind that, while theintensityof light diminishes according to the above law, thequantityremains the same, less resistance, as the area covered increases precisely in the same proportion as the intensity diminishes,—that is, in the ratio of squares.Upper figure.—Gradual discharge between two conductors, in partial vacuum.Lower figure.—Sudden electric discharge through the atmosphere, from left to right.Around the earth and other planets gravity attracts the aqueous vapors in increased density, the same as around the sun; but the electric currents passing between the planets and the sun decompose this aqueous vapor into its constituent gases, hydrogen and oxygen. The oxygen is deposited within the positive electrospheres of the planetary bodies, where it mingles with nitrogen to form our atmosphereand those of the other planets. In this float the aqueous vapors condensed from space, which are lighter than air. (See Tyndall, “The Forms of Water:” “It also sends up a quantity of aqueous vapor which, being far lighter than air, helps the latter to rise.”) These aqueous vapors, condensed into clouds and precipitated upon the earth, form our oceans and their affluents. The hydrogen gas disengaged upon the sun’s surface forms a similar envelope, which is penetrated by the planetary electric currents, and is thus highly heated and rendered incandescent; the glowing hydrogen transmits its heat to the sun’s mass within, which is thus raised to, and permanently maintained in, a liquid or densely gaseous state, its metallic constituents being volatilized in part, and these metallic vapors mingle with the lower strata of hydrogen to form the sun’s photosphere, while, above, the glowing hydrogen grows more pure, and finally, at a distance of hundreds of thousands of miles, is merged into the corona, which is composed, in part at least, of cosmical dust rotating around and repelled by the sun, and which shines partly by reflected light, partly by that of the relatively cooler hydrogen, and partly, perhaps, by electrification of its constituents by the powerful currents passing through it. Each of the planetary bodies, large or small, takes its proportionate part in the generation and transmission of electricity, according to its volume, mass, and motion. As an adjunct to this electrical sequence we have learned that any interruption of such currents between the generatorand the receiver will cause the generating apparatus to glow with diffused electrical light, as is the case with the Wimshurst machine already described. When such connection is removed, it is said, “the whole apparatus bristles with electricity, and if viewed in the dark presents a most beautiful appearance, being literally bathed with luminousbrushdischarges.” Such a phenomenon recalls at once the aurora borealis; and when we find this as a sequence of the electrical storm of the first of September, 1859, before described (“at night great auroras were seen in both hemispheres”), and connect with this the persistence of electricity upon insulated surfaces (see “Electricity in the Service of Man,” page 53: “Glass being a bad conductor, the electricity does not spread all over the plate, but remains where it is produced”), we shall inevitably conclude that there was some partial interruption in the current flowing from the earth to the sun at that moment; and if we recall that at that very instant “suddenly a bright light was seen by each observer to break out on the sun’s surface and to travel across a part of the solar disk,” we shall learn that the processes connected with the production of such a bright light will interrupt in part the terrestrial current. We can readily understand that if this bright light exceeded in electrical intensity that due to the earth’s current, it might temporarily reverse the polarity of the afferent current or retard its flow, like the so-called “backwater” of a mill. It would be like attempting to discharge steam at sixty pounds’ pressure into a vessel filled withother steam at sixty-one pounds. Whence, then, came this bright light? Perhaps from the conjoint action of some other planet, perhaps from sudden chemical disassociation beneath the surface, perhaps by the abnormal piling up of depths of transparent glowing hydrogen or other local disturbance.Position of planets with reference to the generation of sun-spots.—S, the sun; S′, axis of sun’s rotation inclined 7° to plane of planetary rotation; A B, C, D, maximum intensity of planetary action; A′, B′, C′, D′, minimum intensity of same.And this leads to the consideration of the uniformity of solar action. The planetary electrospheres will be constant in their operation if the constitution of surrounding space remains uniform; but we shall find reason to believe that there are currents in the ocean of space, as there are currents in our own seas, and electrical generation will necessarily vary when such currents are encountered. The sun itself in such case, however, will become an automatic regulator, for his density being but one-fourth that of the earth, and the spectroscope having shown his chemical composition to a large extent, we know that his mass must be either liquid or vaporous, and perhaps in part both. Such masses readily respond to variations of temperature, expanding as it rises and contracting as it falls. Hence, if a portion of space were reached where the action of the planetary electrospheres was increased by relative increase of temperature in some interstellar “Gulf Stream,” the sun’s volume would expand and compensation be at once established, while, conversely, with diminution of such planetary action, the solar volume would contract and an increased supply from his reserve store be given out thereby. In this way the condensation relied upon to give us heat forseven or seventeen million years becomes a compensating mechanism, self-operative through the most distant cycles of time. We shall also find in such electric currents an explanation of sun-spots. It is not meant that a full knowledge can be obtained of their minute constitution, nor is it necessary; but the equatorial belt of six degrees, nearly free from sun-spots, we can readily understand to be caused—since sun-spots are depressions in the photosphere down to the deeper and denser cloud strata beneath—by the equatorial piling up of the sun’s atmosphere by its rotation. Any point on the sun’s equator travels at four times the rotational velocity of one on the earth’s equator, but the sun’s attraction of gravity is twenty-seven and one-tenth times that of the earth, so that the piling up of an atmosphere of hydrogen would be considerable, and such depressions would not ordinarily exist there. Similarly, near the sun’s poles we should find a gradual darkening, as is the case; but from five degrees to thirty degrees latitude, the sun, in its rotation, by reason of the inclination of its axis, passes at every point directly beneath the planets, or within their area of control, and here we find the solar spots in their greatest number, size, and intensity. These sun-spots cross the face of the sun in about fifteen days, and vary in development from year to year, having a cycle of 11.11 years from maximum to maximum. They also have a long cycle of about fifty-six years. (See article “The Sun,” in Appleton’s Cyclopædia.) “Wolf, in 1859, presented a formula by which the frequency of spotsis connected with the motions of the four bodies, Venus, the earth, Jupiter, and Saturn. Professor Loomis, of Yale College, has since advocated a theory (suggested by the present writer [Proctor] in 1865, in ‘Saturn and his System,’ page 168, note) that the long cycle of fifty-six years is related to the successive conjunctions of Saturn and Jupiter. But the association is as yet very far from being demonstrated, to say the least.” Should such fact be established, an explanation for it will be found in the direct impact of the condensed electric currents from several planets approaching conjunction, and raising a portion of the sun’s atmosphere suddenlyto a higher temperature and volatilizing an abnormal proportion of the semi-vaporous metallic core beneath. This would form an upburst piling the intensely heated faculæ up on the sides and revealing the relatively darker masses of cloud beneath, the cooler supernatant hydrogen pouring in from the upper layers to fill the returning void. This is precisely what is seen in such spots and their surrounding disturbances. In the article “The Sun,” above quoted, we read, “Mr. Huggins has found that several of the absorption bands belonging to the solar spectrum are wider in the spectrum of a spot, a circumstance indicative of increased absorption so far as the vapors corresponding to such lines are concerned …. Near the great spots or groups of spots there are often seen streaks more luminous than the neighboring surface, calledfaculæ. They are oftenest seen towards the borders of the disk.” This writer also describes “luminous bridges across spots which sink into the vortex and are replaced by others of the numberless cloud-like forms from one hundred to one thousand miles in diameter, the brilliancy of which so greatly exceeds that of the intervening spaces that they must be recognized as the principal radiators of the solar light and heat.” The apparent retardation of the spots most distant from the sun’s equator may also be partially, at least, explained by planetary currents of electricity, as the equatorial atmosphere is deeper and more likely to carry forward such vortices when formed, while the planets act more directly on the sun’s mass beneath their direct influence.Let us consider this retardation of sun-spots somewhat more in detail. Take, for example, the case of a large planet at such orbital position that its direct line of electrical impact will penetrate the photosphere at (say) seven degrees north solar latitude, which is about fifty-two thousand miles from his equator. During its annual revolution this planet will traverse, with its line of energy, every point of the sun’s surface down to seven degrees south latitude and back again to its initial point, thus tracing a close spiral around the sun for fourteen degrees, or about one hundred and four thousand miles in width. The centrifugal force of the solar rotation piles up the photosphere and the chromosphere around the sun’s equator, precisely as our atmosphere is piled up around our own equator. If the planet be a large one (for distance has but little to do with these electrical currents at planetary distances, in which they differ entirely from light, heat, and gravity), or if there be two planets nearly in conjunction, the body of the chromosphere and the surface of the photosphere will gradually become highly heated, for currents of electricity, of themselves, do not directly heat the solar core any more than a like current heats the under carbon of an arc lamp, the high temperature in both cases being altogether due to the incandescent heat of the interposed arc or envelope. Faculæ of intense brightness will then appear upon the photosphere, and these will be driven forward and also outward in the direction of the higher latitudes, producing an oblique forward movement from difference ofrotational speed at different portions of the sun’s surface. Similar phenomena are constantly observed on the surface of the earth in the generation and behavior of cyclones and other atmospheric disturbances. They may be compared to the wake of a vessel anchored in a strong tide-way. These faculæ will slowly raise the temperature of the surface of the sun’s core beneath to the point of eruptive volatilization, and particularly so if the planet is receding from, instead of advancing towards, the solar equator. At some point in advance of the line of planetary energy an eruption of volatilized metals will suddenly occur, first thrusting up a vast area of the photosphere and then bursting it asunder, which will drive these ruptured masses with enormous speed forward and obliquely outward from the equator. Such faculæ (see Proctor’s “Light Science”) sometimes reach a velocity of seven thousand miles per minute, while the sun’s rotational movement at the equator is less than seventy miles per minute. This sudden eruption will be almost immediately succeeded by great expansion and consequent fall of temperature, so that within a few hours the heavy volatile metals begin to condense and rapidly recede into their crater, and the faculæ in front and at the sides will now stream inward to occupy this vacuum with constantly accelerated velocity, pouring over the edges like the rush of waters at the Falls of Niagara. As they sweep downward over the inner rim of the funnel, these streams of faculæ will glow with increased whiteness, and appear tobe sharply cut off at their inner ends; but this is only apparently so, and is due to the position of the observer, who looks almost directly downward upon these descending streams. It is for the same reason that the faculæ appear more brilliant when near the borders of the solar disk (see page 109). Any good view of a sun-spot when analyzed will show the streams of faculæ thus pouring inward, and they are among the most peculiar and conspicuous phenomena to be observed. The drawings of Professor Langley, reproduced in thePopular Science Monthlyfor September, 1874, and July, 1885, are particularly striking in their illustration of these effects, though their significance and interpretation were not then at hand.Analysis of a typical sun-spot. Intersections of lines drawn between AA and MM, CC and MM, show state of active eruption; DD, inflowing faculæ pouring downward over the rim; PP, the same; OO and BB a floating bridge, partially completed, supported by the uprush, and along the line NN torn asunder, and upward into plumes and sprays. The general surface shows the mottlings and faculæ. The partial formation of a loop is shown at XX, YY. The line EQ represents the sun’s equator; fromreartofront, the direction of solar rotation. The line of planetary impact is in rear.But while these heavy metallic vapors so rapidly condense and subside in the forward or initial portion of the sun-spot under observation, new depths of intensely-heated faculæ are generated behind, and these operate with renewed energy upon the fresh surface of the solar core in rear of the original seat of eruption; so that each sun-spot, while in an active state, will exhibit two entirely distinct aspects, the forward portion of the crater in a state of rapid condensation and subsidence of the recently erupted metallic vapors, and with inflowing streams of incandescent hydrogen from the front and sides, and the rear portion of the crater up to its rearward wall, and even streaming forth from beneath it, in a state of violent eruption. The large volcanic craters of the Hawaiian Islands exhibit similar partial eruptions and subsidences progressingsimultaneously in the same depths. The sudden formation of the great incandescent loops and plumes to which Professor Langley calls especial attention, and which have hitherto been so perplexing, can now be readily understood and explained. If one of these inflowing streams be carried partially down into and across the crater, and then caught, in its advance, by the uprush in the central or rear portions of the cavity, it will be at once swept upward alongside the ascending eruption,and either scattered at its forward extremity into sprays and plumes, or else thrown forward bodily in the form of a more or less complete loop. In a sun-spot fifty thousand miles in diameter, such a loop, having a long diameter of twenty thousand miles, if we give a speed to the faculæ of seven thousand miles per minute, would be formed in about seven minutes, during which the sun-spot would itself have advanced less than five hundred miles across the face of the sun. The luminous bridges which form so suddenly across portions of the crater may be explained in a similar manner: they are streams of faculæ floated on the nearly balanced uprush of metallic vapors from beneath.Retardation of sun-spots by continuous development to the rear, and recession in front, as the sun rotates on its axis. The short arrows represent lines of planetary energy; the long arrows show the direction of the sun’s rotation.The dark inner disk represents the solar core, the white circle the photosphere, the mottled area the chromosphere and faculæ, and the dark outer ring the corona. Loops and tufted sprays are shown, caused by inflowing faculæ in front, caught by the uprush of active portions of the sun-spot towards rear.It will thus be seen that a sun-spot is not merely a fixed eruption, like a volcano, but rather a continuous series of eruptions, like a line of activity following, for example, the great terrestrial volcanic curve which extends up the western coast of America, across the Pacific Ocean and Asia, and into Central and Southern Europe, for during its progression its scene of action is constantly being shifted to the rear; it is like a furrow cut by a plough, in which the upturned sod is constantly falling in at one end of the furrow while the plough is cutting a new furrow at the other, except that in this case the plough is relatively fixed overhead, and the field itself passes along beneath it. Consequently, the center of activity of a sun-spot is only in its rear portions, generally considered, and the whole sun-spot is gradually retreating, by successive filling up in front and opening out behind, fartherand farther to the rear,—that is to say, to the east,—so that retardation relatively to the rotational advance of the photosphere necessarily ensues.But when the sun-spot is developed upon or near the equatorial line this retardation is not so considerable, for the deeper layers of the photosphere in those regions are slower to act and require greater energy to affect them, so that all except deep and violent eruptions fail to show themselves at the surface at all, and the heated faculæ are carried directly forward along the surface of the equatorial swell, so that the center of activity is driven forward more rapidly than in the higher latitudes, and the rate of progression is more nearly coincident with that of the photosphere. But if these facts are correctly stated and explained, we may have to revise our calculations of the sun’s rotational period, for retardation to some extent must occur in all cases, if in any.A sun-spot, we thus perceive, is an elongated wave or ridge of eruption along the rotational direction of the sun’s body. Why, then, it may be asked, is not this line of eruption continuous entirely around the sun? For the same reason, it may be answered, that our own cyclones are not continuous, though caused substantially in the same manner, and that volcanic eruptions only occur at long intervals, though the forces at work are continuous. Lowering of temperature follows swiftly after eruption, and as the deeper structures of the solar nucleus become gradually affected, instead of volatilization of the outer layers of the surface, we will have diffused gaseous expansion of large portions,and finally of the entire solar mass, which cannot as a whole be volatilized by any conceivable planetary energy. We see these operations exemplified in heating a bar of copper in a Bunsen flame; the latter first turns green from surface volatilization of the copper, but as the heat is communicated to the deeper structures the green flame disappears, and the whole additional heat goes to raise the temperature of the mass.These processes in the sun are thus seen to be self-compensatory in their nature. They are the means provided to distribute the restricted areas of abnormally heated photosphere over the solar surface, and finally to cause the absorption of the whole excess of heat in the sun’s central mass. The balance is so evenly maintained, however, that, were all the planets equally distributed with reference to the sun’s surface, such sun-spots would be the exception and not the rule, and their distribution would be equal and constant; but, as the planets continually change their positions with reference to the sun and to each other, only by some such provision of nature could the internal structure of the sun be maintained without serious derangement, or, indeed, final disruption. So nature distributes her stores of heat upon the earth. These beautiful self-compensations we shall find suddenly appearing, as we advance, in all parts of the field of astronomical research.It may seem like temerity to advance statements so positive and specific as to the cause, constitution, and progression of sun-spots, in the absenceof any considerable accumulation of observations to sustain them, but the few examples which we have noted are in accordance with these views, and when attention is once called to the basic principles on which they depend, observations will doubtless be made in abundance to prove or disprove what has been here stated. The mere fact of a differential rate of advance among sun-spots, as they pass across the solar face, of itself demonstrates that the active causes of these phenomena must be extra-solar, and if so, their only possible dynamic source must be looked for in the planets, and the remaining conclusions will of necessity follow as a corollary. We may even, by merely examining an accurate drawing of a sun-spot, determine its position and direction upon the solar sphere from which it was delineated by its lines of active eruption and influx of faculæ, and also whether it be a new spot or one which has passed entirely beyond its active stage and is about to finally disappear.As for the faculæ which striate the photosphere, the mottlings and so-called “willow-leaves,” any one who will quietly gaze downward upon the turbid surface of the Mississippi or other similar river, in mid-channel, will see plenty of such faculæ: the river is full of them. The heavier, intermingled clay, slowly subsiding, is caught up in the turmoil beneath the surface and swept upward in elongated ovals and eddies, the larger swells nearly colorless, and others of all shades of ochre and yellow, and the whole as richly mottled, sometimes, as the variegated pattern of a Persian carpet. If we substitutefor the subsiding clay the rapidly sinking heavy metallic vapors, and enlarge the scale from the dimensions of the river to those of the sun, we will have the mottled solar surface with its kaleidoscopic changes, the so-called “willow-leaves,” and the faculæ in all their glory. A careful study of the sun will show most clearly that only in some such explanation as the present view affords can a rational basis for its varied phenomena be found.Illustrating complex lines of planetary electrical energy produced by inclination of sun’s axis.—A B, A′ B′, plane of planetary orbits.Upper figure shows sun’s axis inclined laterally; lower figure, from front to rear, and at right angles to former.C, chromosphere; E E, solar equator; A B, A′ B′, lines of planetary electric currents; F, latitude covered by vertical position of planets, 14° in width; P P, sun’s axis.If the sun’s equator were coincident with the plane of the planetary orbits, it is obvious that all the planetary energies would be directed, whatever the position of the planets around the sun, immediately upon this equatorial great circle, and that, at each revolution upon his axis, corresponding nearly to our calendar month, the same part of his sphere would be exposed to these direct currents, so that the intensity would be, in its aggregate, nearly a constant quantity. But, by reason of the sun’s axial inclination of seven degrees to the plane of the planetary orbits, a far more complex and important condition of affairs ensues. It will be seen at once that the plane of the planetary orbits intersects the sun’s equator at opposite sides, and that, from a minimum of nothing, this line reaches a maximum, twice in each circumference, of seven degrees, one north and the other south of the equator, and that this arc of fourteen degrees, thus traversed by every planet in its orbital rotation around the sun, measures more than one hundred thousand miles from north to south upon the solar surface, nearly one-half the distance which separates theearth from the moon. If all the planets were in conjunction or nearly so, on one side of the sun, for example, and in the vertical plane of the sun’s axis, they would continue to deliver their electrical currents with their greatest intensity upon a single point of his surface fifty-two thousand miles north of his equator, while the opposite point, one hundred and four thousand miles distant, would be unaffected by any direct currents at all. Conversely,if in conjunction on the opposite side of the sun, they would continue to deliver these currents upon a corresponding point fifty-two thousand miles south of the equator; but if in conjunction in the vertical plane transverse to the sun’s axial inclination, these currents on either side of the sun would be delivered directly upon the solar equator. The importance of this will be understood when it is considered that for many of our years such planets as Jupiter and Saturn must continue to direct their currents upon a very slowly changing point of the sun’s surface, by reason of their vast annual rotational period, while with the earth and the interior planets these various points are struck with ever-increasing rapidity as the year decreases in length with the different planets, the earth, Venus, and Mercury. There is a solar equinoctial, so to speak, just as there is a terrestrial equinoctial in which the sun crosses the line twice each year, and the meteorological disturbances faintly shown on the earth at such times are vastly increased on the sun, and rendered far more complex by the interaction of many planets upon the sun, instead of a single sun upon each planet. While our equinoctial has to do with gravity and light and heat, and probably magnetism, the solar equinoctial deals with the vast electrical streams which feed its fires and set it boiling with furious energy, first at one point, then at another, until the increment has been absorbed and adjusted, and thus equalized throughout his mass. What a new interest this must arouse in our study of sun-spots, faculæ, prominences, sun-storms,and the vast panorama of solar action hung up before our astonished eyes! A new world here awaits its Columbus.But not only the planets thus gather, so to speak, electricity for the sun’s support from space; the moon also must do its part, as it rotates in the same manner, subject to the sun, and has its own motion through space. But an examination of the moon shows no atmosphere and no aqueous matter visible to us, and also the singular fact that it constantly presents one side only to the earth. R. Kalley Miller, in his “Romance of Astronomy,” article “The Moon,” says, “After an elaborate analysis, Professor Hausen, of Gotha, found that it could be accounted for only by supposing that the side of the moon nearest us was lighter than the other, and hence that its center of gravity was not at its center of figure, but considerably nearer the side of it which is always turned away from us. He calculates the distance between these centers to be nearly thirty-five miles, evidently a most important eccentricity, when we remember that the radius of the moon is little over a thousand miles. It must have been produced by some great internal convulsion after the moon assumed its solid state; but the forces required to produce this disruption are less than might at first sight appear necessary, owing to the fact that the force of gravitation and the weight of matter are six times less at the moon than with us.” Those who are fond of the so-called “Argument of Design” will be gratified to learn that, if the moon had a rotation upon its ownaxis similar to that of the earth, all life—past, present or future—would have been impossible on that satellite or planet; and that, on the contrary,—provided she always turns the same side of her surface to the earth,—it is quite possible that air, water, and life may exist, or may have existed, on the opposite side of the moon, but not otherwise. In fact, air and water must now exist on the opposite side; and, since her whole supply will thus be condensed upon half her surface or less, even with her small force of gravity, it may be quite sufficient in quantity and density for the support of animal, vegetable, or even human life. By reason of this difference in the lunar center of gravity, the side presented to the earth in physical position is similar to the summit of a mountain upon the earth’s surface two hundred miles high, and surely we would not expect to find much air or water or life at that altitude. But the opposite side would resemble a champagne country at the foot of this enormous mountain, and might be well fitted for human existence. Now, we know that similar electricities repel each other, and air or gases charged with similar electricities are equally self-repellent. Professor Tyndall, in his “Lessons in Electricity,” says, “The electricity escaping from a point or flame into the air renders the air self-repulsive. The consequence is, that when the hand is placed over a point mounted on the prime conductor of a good machine, a cold blast is distinctly felt …. The blast is called the ‘electric wind.’ Wilson moved bodies by its action; Faraday caused it to depressthe surface of a liquid; Hamilton employed the reaction of the electric wind to make pointed wires rotate. The wind was also found to promote evaporation.”Fig. 1, mutual repulsion of similarly electrified pith-balls; 2, the electrical windmill, atmospheric repulsion; 3, repulsion of a flame by electricity; 4, electrical distribution around an oval conductor; 5, mutual attraction of opposite electricities; 5a, mutual repulsion of similar electricities; 6, mutual repulsion of electrospheres of earth and moon; 7, mutual repulsion of electrospheres of sun and comet.While electrical repulsion is doubtless analogous to, and correlative with, the attraction of gravitation, this force, and even gravity itself, has been sometimes interpreted as derived from the mutually interacting molecules of space itself. We may even learn somewhat of how such repulsions of similar and attractions of opposite electrospheres might occur. We constantly speak of positive and negative electricity as though these were different fluids, but such expressions are employed only in the same manner as the analogous terms, heat and cold. We know, of course, that cold is the relative absence of heat, the dividing line being not a fixed, but a constantly changing one, so that one body is cold to another by reason of relative, and not absolute, deprivation of heat. It is well known, however, that cold, which is purely a negative state, manifests the same apparent radiant energy as heat. A vessel near an iceberg is exposed to a wave of cold, precisely as of heat from a heated body at the same distance. This, of course, is due to abstraction and not to increment. All space being occupied by attenuated matter in a state of unstable electrical equilibrium, as we say, which simply means a condition ready to be raised or lowered in tension by absorption from or into outside media, all concrete bodies floating in that space must have an electrical potentialeither equal to, or higher, or else lower than that of their surrounding space. A solitary body in space, if we can conceive of such, in either a higher or lower state of electrical tension, would be drawn upon from all sides to equalize the distribution and restore the general average. But if two bodies occupy the same field, and are widely different from each other in electrical potential, one higher and the other lower than that of space, this distribution will be towards each other, and must be manifested by mutual attraction. But if, on the contrary, these two bodies are both equally higher or lower than the spatial average, they have nothing to give to each other, but have this difference to give to or receive only from outer space, and hence they will be drawn apart or, as we say, mutually repelled. The case is similar to what we see in the case of bodies of water at various levels. Suppose there be a lake of a fixed level, and communicating with it and with each other, by open channels, two ponds of water occupying an island in the middle of the lake. If one of these ponds be higher in level and the other lower than the lake, their waters will rapidly converge, the higher flowing into the lower; but if both are at the same level, and higher than the lake, they will flow apart into the lake. Or, if both are at the same level, and lower than the lake, the water of the latter will equally flow from outside into both ponds, and their waters will still be held separate from each other. The analogies of these various levels may be pursued to any desired extent, as electrical tensionsfind their most exact analogies in the pressures of bodies of water at different levels and of different quantities, and these analogies are those most constantly used in the interpretation of such electrical phenomena.The great electrical activity of the electrospheres of the earth and moon, while they discharge their tremendous currents directly into the sun, at the same time must cause their similarly electrified atmospheres to mutually repel each other, while gravity continues to operate to maintain the earth and moon at their fixed distances from each other, and to retain their gaseous envelopes around their own bodies. The result must be that these similarly electrified atmospheres repel each other with a force proportioned to their masses of atmosphere and the intensity of the electricities of each. The moon’s axial rotation being completed but once in twenty-eight days, and that of the earth once in each day, and the moon’s mass and volume being so much less than those of the earth, whatever of electrified air or moisture she may have (and she must have both, proportionate to her attributes) would have been driven as by a cyclone to the opposite side of the moon and there retained. Now, with an atmosphere and water only on one side of the moon, and that the side opposite the earth, it is obvious that a rotation on her axis at all resembling that of the earth would carry every part of her surface, at each complete rotation, from a region of air and moisture into one deprived of both, and in such a condition she would of necessitybe deprived of both life and its possibility; hence, as the laws of nature compel the lunar atmosphere and moisture to reside permanently on the side always opposite the earth, a co-ordinate arrest of the moon’s axial motion with reference to the earth could alone compensate for such a state of things, and, curiously enough, we find as a solitary exception, compared with the planets, that such is the case. The moon unquestionably has both atmosphere and water on its opposite side. In his recent work, “In the High Heavens,” Professor Ball reviews the physical conditions of the other planets as possible abodes of life. He pronounces against the moon because night and day would each be a fortnight in length; but this is surely no objection, for even in Norway and Greenland such nights and days are not uncommon at different seasons, and thousands of human beings, even as at present constituted on earth, spend their lives there in content and happiness. That the moon also would be terribly scorched by the long day and frozen by the long night does not necessarily follow, for the atmosphere of Mars, that author says, “to a large extent mitigates the fierceness with which the sun’s rays would beat down on the globe if it were devoid of such protection.” As the moon’s opposite face must have a double quota both of atmosphere and clouds, the difficulty will be correspondingly less than on Mars; and as for the “lightness” of bodies on the moon, they would probably get along quite as well as mosquitoes and like “birds of prey” in the marshes along our coasts. The author refersconstantly toourbodies; for example, “Couldwelive on a planet like Neptune?” No, we could not; we would be dead before we got there. Nor couldwelive in the bark of a tree, or at the bottom of the ocean, or in a globule of serum; but living beings are found there nevertheless. The principle is that wherever life is possible there we may expect to find life; and surely life is, or has been, or will be possible, not only on the moon, so far as our knowledge of physical conditions can go, but also on some of the other planets. Of course each planet has its life stage, but this applies not only to the earth, but to all the other planets as well, and not only to the planets of our own system, but to those of all other solar systems. Each has had, or will have, its stage in which life is possible, and these planets may be like human habitations, in which whole races at times migrate from one home to another. There is no conceivable reason why this may not be the general law of creation, and every analogy leads us to believe that it is so.It has been recently announced that, from telescopic observations, the atmosphere of Mars must be at least as attenuated as that among the highest mountainous regions of the earth, if this planet has any atmosphere at all. That it must be far less dense than that of the earth at sea-level is obvious, for the mass and volume of Mars are very much less than those of our own planet; but that Mars is devoid of a gaseous envelope or atmosphere is contrary to what we know of all sidereal physics. The sun, the fixed stars, the comets, the nebulæ, andeven the meteorolithic fragments which fall upon the earth, all show the same elementary chemical constitution as the earth itself, and we cannot believe that Mars alone is differently constituted from every other body we have been able to examine. We have direct evidence, on this planet, of polar snows and their melting away under the sun’s heat; we see the apparent areas of sea and land; it has its moons as the earth has hers, and exhibits all the characteristic phenomena of the earth and other planets. All sidereal bodies that we know of, except, perhaps, our moon, which exception we have fully accounted for, are found to be surrounded by gaseous envelopes or atmospheres of some sort. The sun, the fixed stars, the nuclei of comets, the condensing nebulæ, the planets Jupiter and the earth, which are those under our most direct observation, and even the meteorites, when examined, reveal the presence of many times their own volumes of independent atmospheric gases; and whatever may be the theory of the origin or development of Mars, it must have been subjected to the same influences, the same environment, and the same processes of creation as those of our solar system generally; and that this body alone should possess no gaseous envelope—for the denial of atmosphere denies, at the same time, the presence of any or all surrounding gases—is quite incredible. Only the most positive, direct, and long-continued proofs of such fact could be accepted, and even then the history of all scientific progress shows that what are believed to be facts themselves fluctuate like fancies till, bytheir accumulated force, they solidify into universally accepted demonstration. The fact, moreover, that the atmospheres of the smaller planets are more attenuated than our own and those of the larger ones denser has no bearing, in itself, on the probability of the existence of life on these other planets, for in our own atmosphere oxygen, which is the efficient element, is diluted with four times its quantity of inert nitrogen. These proportions doubtless vary largely in other atmospheres, so that the oxygen may be much richer in some and far poorer, relatively, in others. The mere fact that the presence of nitrogen, probably, and aqueous vapor, certainly, depends on the gravity of the mass of each planet, while the oxygen is due to electrolytic decomposition induced by the combined volume, mass, and rotation, and other causes,—such as the axial inclination of such planets, for example,—renders these variations in the constitution of planetary atmospheres a certainty. As Mars has a diameter much more than one-half that of the earth, and a diurnal rotational period nearly the same, while his mass, which controls the action of gravity, is only about one-ninth that of the earth (see Appleton’s Cyclopædia), it is obvious that his oxygen-gathering power, compared with that for accumulating nitrogen and aqueous vapor, is much higher than that of the earth, and we should expect to find there an attenuated atmosphere very rich in oxygen, and with a relatively smaller proportion of aqueous vapor, or even water, on his surface. Such seem to be the facts as far as observed.In operating an electric machine the strength of the current is directly proportionate to the speed of rotation,—that is to say, to the velocity of the generating surface; for example, of the Wimshurst induction machine it is stated (page 63, “Electricity in the Service of Man”), “These four-and-one-half inch discharges take placein regular succession at every two and a half turnsof the handle.” It is also a well-established law of electrolysis that “The amount of decomposition effected by the current is in proportion to the current strength.” Professor Ferguson (“Electricity,” page 225) says of the voltameter, an instrument devised by Faraday, and used for testing the strength of currents by the proportionate decomposition of acidulated water, “Mixed gases rise into the tube, andthe quantity of gas given off in a given time measures the strength of the current.” Roughly estimating the diameter of Mars at five-eighths, the surface velocity at three-fifths, and the mass at one-ninth those of the earth, this planet should have an atmosphere containing about sixty per cent. of oxygen and forty of nitrogen, with a barometric pressure at sea-level of about six and one-half inches of mercury. This would be an excellent atmosphere,—about equal in its quota of oxygen for each respiration to that of the higher areas of Persia, a great country for roses. The aqueous vapors lying low and near the surface would serve as a vaporous screen to concentrate and retain the sun’s heat and retard radiation from that planet. Nothing in particular seems to be the matter with Mars.On the contrary, the mass of Jupiter is so great, and his attraction of gravity so powerful, that it is only by his exceedingly rapid diurnal rotation (once in less than ten hours) that it is possible for him to accumulate any effective percentage of oxygen at all. But there is certainly plenty of water there.We may approximately compute, in general terms, the proportion of oxygen in the atmospheres of the other planets in the same way. Neptune, it is true, is so far distant from the sun that the solar orb only “appears about the same magnitude as Venus when at its greatest brilliancy, as viewed from the earth,” but we must not forget that “theintensityof the sun’s light would be more than ten thousand times greater than that of Venus” (Professor Dunkin, in “The Midnight Sky”). Unless the moon gathers a portion of the earth’s oxygen (the planetary satellites, like Saturn’s rings, thus constituting in their rotations a constituent part of the planets themselves), the percentage of this gas in her atmosphere must be exceedingly small, for her axial rotation has a period of a whole lunar month, being the same as that of her revolution around the earth as a center.The absence of apparent atmosphere and moisture from thevisiblelunar surface has already been mentioned and explained. The means by which this fact has been approximately determined are described by Professor Dunkin, in “The Midnight Sky,” as follows: “Among the many proofs of the non-existence of a lunar atmosphere, it maybe mentioned that no water can be seen; at least there is not a sufficient quantity in any one spot so as to be visible from the earth. Again, there are no clouds; for if there were, we should immediately discover them by the variable light and shade which they would produce. But one great proof of the absence of any large amount of vapor being suspended over the lunar surface is the sudden extinction of a star when occulted by the moon. The author has been a constant observer of these phenomena, and, though his experience is of long standing, he has never observed an occultation of a star or planet,especially at the unilluminated edge of a young moon, without having his conviction confirmed that there is no appreciable lunar atmosphere …. Professor Challis has subjected the results of a large number of these observations to a severe mathematical test, but he has not been able to discover the slightest trace of any effect produced by a lunar atmosphere.”In Appleton’s Cyclopædia, article “The Moon,” it is stated that “Schröter (about 1800) claimed to have discovered indications of vegetation on the surface of the moon. These consist of certain traces of a greenish tint which appear and reappear periodically; much as the white spots covering the polar regions of Mars …. As we are able, under the most favorable conditions, to use upon the moon telescopic powers which have the effect of bringing the satellite to within one hundred and fifty to one hundred and twenty miles of us, we should doubtless notice any such markedchanges on her surface as the passage of the seasons produces, for example, on our own globe.” Very recently (August 12, 1894), it has been stated, Professor Gathmann has observed a peculiar green spot about forty by seventy miles in area near the crater of Tycho Brahe, “on thenorthwestern edgeof the satellite’s upper limb,” which had disappeared twenty-two hours afterwards.We understand, of course, that the moon’s librations, by the variation of position of the lunar body, enable us to see, at times, around the edge of this satellite somewhat, so that, instead of observing only one-half, we can in this way see nearly six-tenths of her surface, but not at the same time, of course. When the moon is dark it occupies a position between the earth and the sun, and only its opposite face is illuminated. In this position the attraction of solar gravity and the attraction of the electrically opposite solar electrosphere both accumulate their forces upon the moon’s atmosphere in the same line as the repulsion of the earth’s similar electricity, so that the lunar moisture and atmosphere are, at this part of her subordinate orbit, most powerfully forced away from the direction of the earth. As the moon now proceeds towards her first quarter, the terrestrial repulsion drives her atmosphere radially outward, while solar gravity and electrical attraction tend to hold it in the direction of the sun. The result will be an electrospheric libration, so to speak, and the moon’s atmosphere and moisture will be carried around towards its illuminated face and, to someextent, will overlap the area of terrestrial repulsion. But as the moon advances this will gradually diminish, soon cease, and finally be reversed as it again approaches darkness. We can now understand why the green surface, if it really was due to vegetation, appeared along thelunar marginat the time described above, and also that the observation of planetary occultations “at the unilluminated edge of the young moon” was the very worst part of the moon and its orbit in which to look for air or moisture; as the sun’s influence is then directlyaway fromthe unilluminated surface of the moon, and his “pull” would have, in fact, still further denuded the very portion most persistently examined, and where this absence of atmosphere wasespeciallynoted.When considering the transference of energy from the peripheral regions of the solar system to the center, its conversion there into a new form of molecular force, and its subsequent distribution, we find a curious and instructive parallel in the action of the reflex nervous system of animal life. This system is one in which the brain or other conscious center of nerve-energy takes no part. Tickle the foot of a child, for example, and its whole muscular system is thrown into uncontrollable convulsions of laughter. Here an exciting contact with the terminal filaments of the afferent or sensory nerves is rapidly carried into the local nerve-center of this part of the system,—that is, the sensory column of the spinal cord. This center of ganglionic nerve-matter lies directly against the correspondingmotor mass, both freely communicating with each other. The sensory current passing into its central ganglion undergoes some peculiar change of character, probably one of intensification, such as is observed in the action of the condenser of an electrical machine, through which sensory ganglion, thus raised in potential, it passes to the motor ganglion adjacent, where it is instantly transformed into an entirely different form of energy. The sensory character has now entirely disappeared, and it has been converted into and is flashed forth as motor energy to the different muscles of the body, which are immediately contracted, the violent molecular motion of the fibres being at once converted into muscular motion in mass. The changes are entirely analogous to those we see in the different conversions of energy in our solar system. Considering the surface of the body as a planetary electrosphere, it is acted upon by excitation from without; currents of energy are engendered, which are at once transmitted to the sensory ganglion, corresponding to the hydrogen atmosphere or electrosphere of the sun; intensification of action here ensues, the current passing through this ganglion or atmosphere into the solar body itself, which corresponds to the motor ganglion; both ganglia are now highly excited; the electrical force is converted into the radiant molecular motor energy of heat and light in the sun and muscular excitement in the body, and these are flashed forth and find scope for their action within the body of the subject or upon the surface of the planets, whichlie, like the muscular structure of the body, within the genetic electrosphere where, acted upon from without and by agencies entirely external, moving contact has induced the primary molecular action, which was then instantaneously transferred to the center, there converted into another form, that of motor energy, and thence sent forth to produce action in the muscles of the body in the one case, and in the other upon the planetary bodies and their satellites and other structures which occupy surrounding space.

CHAPTER IV.THE SOURCE OF SOLAR ENERGY.The remarkable resemblance between the mode of operation and effects of these electrical induction machines and the vast rotating electrosphere of the earth must be at once apparent. The operation is precisely the same, and the results must,pari passu, be substantially similar. We need not seek for precise parallelism of structure, because these machines themselves, it has been shown, widely differ in structure among themselves. But the almost infinitely more vast terrestrial electrosphere, which cannot be less than ten thousand miles in diameter, and perhaps much more (if we may form an opinion from the relative magnitude of the field of action of the hydrogen envelope which constitutes the solar electrosphere), rotating in the attenuated vapors of space, among which vapors that of water plays a most important part, and which vapors constantly impinge with various disturbances of contact against the more and more attenuated layers of the terrestrial atmosphere, and which gradually, from within outward, less and less partakes of the earth’s rotation until, finally, its rotatory movement is lost in the vast ocean of space, establishes the certainty that enormous quantities of electricity must there be disengaged, preciselyas in the machines which we have described, and to learn the potential or active pressure of this electricity we have only to consider the fact that we find a rise so rapid, as we ascend through our atmosphere, that the potential increases by from twenty to forty volts for each foot. That these currents are transmitted to the sun without appreciable resistance we already know, and that they are there transformed into light and heat we can, from the previously cited experiments, see.But it may be urged that the resistance of such attenuated vapors in space, and the generation of electricity in such quantities, would inevitably retard and finally destroy planetary motion. The sufficient answer to this is found in the consideration that the same facts must exist under any possible mode of organization of our solar system, and that such interference, besides, must have absolutely prevented its formation at all, if such were the case. All the matter of our planetary system together is only one seven-hundred-and-fiftieth that of the sun; if this were added to the sun’s bulk it would but slightly enlarge it. But all this solar and planetary matter together, if distributed over the space occupied by our planetary system,—and, by the nebular hypothesis of the organization of our solar system, this is requisite,—and having an axial diameter one-half that of its equatorial (see Proctor’s “Familiar Essays on Scientific Subjects,”—“Oxygen in the Sun”), would have had a density of only about one four-hundred-thousandth that of hydrogen gas at atmospheric pressure. This nebular mass musthave had a diameter at least sixty times that of the distance of the earth from the sun and a depth of thirty times its distance. That this enormous mass of attenuated matter should ever have been made to rotate as a whole by any force of attraction, repulsion, or rotation, with a tenuity so great that, if measured by an equal volume of hydrogen gas,—the lightest substance known to us,—it would have furnished material for four hundred thousand such systems as ours, presupposes a resistance so slight that the planets themselves, when coagulated out of such a mass, could never in any conceivable time exhibit retardation from such a source; and we know to a certainty that such attenuated vapors do exist in space, for electricity cannot be transmitted through a vacuum, and it is transmitted with perfect freedom between the earth and the sun. But it may be said that the laws were then different. If they were different then, they are doubtless different now. If, on the other hand, we assume that the bodies of which our solar system is composed were simply aggregated into concrete masses from meteoric dust, the difficulty is not lessened; for if the resistances to their operation now are such as to perceptibly retard their motions, they must have operated still more powerfully to originally prevent them; while, if hurled forth by an almighty fiat, complete from the hand of creative energy, the same force which impelled them forward must have also established the laws under which they now move.It is calculated that our earth must be losingtime, by tidal retardation, at the rate of one-half the moon’s diameter in each twelve hundred years (see Proctor, “Light Science for Leisure Hours,”—“Our Chief Timepiece Losing Time”), and that “the length of a day is now more by about one eighty-fourth part of a second than it was two thousand years ago.” Perhaps, however, we may discover that these changes are themselves periodic and increase in cycles to a maximum, and then diminish, as is the case with magnetic, planetary, and stellar variations, and other similar changes, when sufficiently long observed; for while such changes may very well accompany a theory under which our system and all other systems are slowly running down to decay and death, it is entirely incompatible with the primal forces under which theymusthave been originally formed. In other words, if the tides are dragging back our earth without compensation, this dragging back can only come from the oceanic deposit of water on the earth from the aqueous vapors of space which do not partake of the planetary rotation and orbital movement of the earth. But if these can now retard the earth’s motion, they must have originally prevented it in the beginning. This loss of time is, moreover, merely inferential from mathematical computations, and its basis is found in the belief that all the operations of nature are in a slow process of degradation, and the calculated loss itself may be merely theoretical, and not true in fact. Professor Proctor himself concedes the uncertainty of this alleged retardation when he says in the samearticle, “At this rate of change our day would merge into a lunar month in the course of thirty-six thousand millions of years. But after a while the change will take place more slowly, andsome trillion or so of yearswill elapse before the full change is effected.”While the processes of nature are generally believed to be running down, everything is bent to that belief; but the forces of nature must, nevertheless, be uniform and supreme, for it is by these forces that the expected results are to be achieved. That changes occur constantly is inevitable, but the source of these must be looked for in the interaction of original forces, and not in the degradation of systems. There is reason to believe, in fact, that the repulsion of the terrestrial electrosphere by that of the moon may itself be sufficient to counteract such retarding force of lunar gravity, for the tides upon earth are not merely oceanic, but atmospheric, and on the latter the electrical repulsion of the moon must act very powerfully and with directly counteractive effect.Planetary generation and transmission of electrical energy.—A, the planet; B, electrosphere showing circles of gradually diminishing rotation; E, interplanetary space; D, curve of gradually diminishing rotation; F, F, currents of electricity flowing to the sun; S, direction of the sun.Let us now apply the preceding principles to the problem under review. All planetary space is pervaded with attenuated vapors or gases, among which aqueous vapor occupies a leading place. The planets and all planetary bodies, having opposite electrical polarity from the central and relatively fixed sun, by their orbital motions around and constant subjection thereto act as enormous induction machines, which generate electricity from the ocean of attenuated aqueous vapor, each planet being surroundedby an enormous electrosphere, carried with the planet in its axial and orbital movements, the successive atmospheric envelopes gradually diminishing in rotational velocity until merged into the outer ocean of space. As the planets advance in their orbits they plunge into new and fresh fields, and, as the whole solar system gradually movesonward through space, these fields are never re-occupied. These electrospheres, by their rotation, generate enormous quantities of electricity at an extremely high potential,—so high that we can scarcely even conceive it,—and this electricity flows in a constant current to the sun, where it disappears as electricity, to reappear in the form of solar light and heat. These planetary currents also flow towards such other negatively electrified bodies as may exist in space—the comets and fixed stars, for example—in proportion to their distance; for, since resistance is not appreciable between ourselves and the sun, as is also the case with light, so, like light, our electricity must pass outward as well as inward to take part in the harmonious operations of the whole universe. But it should be noted that the distribution of electric energy in the form of currents is quite different from that of light or other radiant energy; for while light is diffused from a center outward through space, electric currents, on the contrary, are concentrated and directed along lines of force to concrete centers of opposite polarity. As a consequence, the intensity of light decreases according to the squares of the distances traversed plus the resistance to the passage of the light itself, while the electric current is only diminished by the resistance of the medium through which it passes. As the light of the sun has a velocity of one hundred and eighty-eight thousand miles per second, and the electric current between the earth and the sun the same, it will be seen that the resistance is practically alike for these two formsof energy. Indeed, the striking resemblance between the ethereal vibrations which constitute light and heat and exceedingly rapid alternating currents of electricity through molecular media may suggest that the transformation of one force into the other is some sort of a “step-up” or “step-down” process, much higher in degree, but of the same character as the well-known analogous electrical transformations used in the arts. It should also be borne in mind that, while theintensityof light diminishes according to the above law, thequantityremains the same, less resistance, as the area covered increases precisely in the same proportion as the intensity diminishes,—that is, in the ratio of squares.Upper figure.—Gradual discharge between two conductors, in partial vacuum.Lower figure.—Sudden electric discharge through the atmosphere, from left to right.Around the earth and other planets gravity attracts the aqueous vapors in increased density, the same as around the sun; but the electric currents passing between the planets and the sun decompose this aqueous vapor into its constituent gases, hydrogen and oxygen. The oxygen is deposited within the positive electrospheres of the planetary bodies, where it mingles with nitrogen to form our atmosphereand those of the other planets. In this float the aqueous vapors condensed from space, which are lighter than air. (See Tyndall, “The Forms of Water:” “It also sends up a quantity of aqueous vapor which, being far lighter than air, helps the latter to rise.”) These aqueous vapors, condensed into clouds and precipitated upon the earth, form our oceans and their affluents. The hydrogen gas disengaged upon the sun’s surface forms a similar envelope, which is penetrated by the planetary electric currents, and is thus highly heated and rendered incandescent; the glowing hydrogen transmits its heat to the sun’s mass within, which is thus raised to, and permanently maintained in, a liquid or densely gaseous state, its metallic constituents being volatilized in part, and these metallic vapors mingle with the lower strata of hydrogen to form the sun’s photosphere, while, above, the glowing hydrogen grows more pure, and finally, at a distance of hundreds of thousands of miles, is merged into the corona, which is composed, in part at least, of cosmical dust rotating around and repelled by the sun, and which shines partly by reflected light, partly by that of the relatively cooler hydrogen, and partly, perhaps, by electrification of its constituents by the powerful currents passing through it. Each of the planetary bodies, large or small, takes its proportionate part in the generation and transmission of electricity, according to its volume, mass, and motion. As an adjunct to this electrical sequence we have learned that any interruption of such currents between the generatorand the receiver will cause the generating apparatus to glow with diffused electrical light, as is the case with the Wimshurst machine already described. When such connection is removed, it is said, “the whole apparatus bristles with electricity, and if viewed in the dark presents a most beautiful appearance, being literally bathed with luminousbrushdischarges.” Such a phenomenon recalls at once the aurora borealis; and when we find this as a sequence of the electrical storm of the first of September, 1859, before described (“at night great auroras were seen in both hemispheres”), and connect with this the persistence of electricity upon insulated surfaces (see “Electricity in the Service of Man,” page 53: “Glass being a bad conductor, the electricity does not spread all over the plate, but remains where it is produced”), we shall inevitably conclude that there was some partial interruption in the current flowing from the earth to the sun at that moment; and if we recall that at that very instant “suddenly a bright light was seen by each observer to break out on the sun’s surface and to travel across a part of the solar disk,” we shall learn that the processes connected with the production of such a bright light will interrupt in part the terrestrial current. We can readily understand that if this bright light exceeded in electrical intensity that due to the earth’s current, it might temporarily reverse the polarity of the afferent current or retard its flow, like the so-called “backwater” of a mill. It would be like attempting to discharge steam at sixty pounds’ pressure into a vessel filled withother steam at sixty-one pounds. Whence, then, came this bright light? Perhaps from the conjoint action of some other planet, perhaps from sudden chemical disassociation beneath the surface, perhaps by the abnormal piling up of depths of transparent glowing hydrogen or other local disturbance.Position of planets with reference to the generation of sun-spots.—S, the sun; S′, axis of sun’s rotation inclined 7° to plane of planetary rotation; A B, C, D, maximum intensity of planetary action; A′, B′, C′, D′, minimum intensity of same.And this leads to the consideration of the uniformity of solar action. The planetary electrospheres will be constant in their operation if the constitution of surrounding space remains uniform; but we shall find reason to believe that there are currents in the ocean of space, as there are currents in our own seas, and electrical generation will necessarily vary when such currents are encountered. The sun itself in such case, however, will become an automatic regulator, for his density being but one-fourth that of the earth, and the spectroscope having shown his chemical composition to a large extent, we know that his mass must be either liquid or vaporous, and perhaps in part both. Such masses readily respond to variations of temperature, expanding as it rises and contracting as it falls. Hence, if a portion of space were reached where the action of the planetary electrospheres was increased by relative increase of temperature in some interstellar “Gulf Stream,” the sun’s volume would expand and compensation be at once established, while, conversely, with diminution of such planetary action, the solar volume would contract and an increased supply from his reserve store be given out thereby. In this way the condensation relied upon to give us heat forseven or seventeen million years becomes a compensating mechanism, self-operative through the most distant cycles of time. We shall also find in such electric currents an explanation of sun-spots. It is not meant that a full knowledge can be obtained of their minute constitution, nor is it necessary; but the equatorial belt of six degrees, nearly free from sun-spots, we can readily understand to be caused—since sun-spots are depressions in the photosphere down to the deeper and denser cloud strata beneath—by the equatorial piling up of the sun’s atmosphere by its rotation. Any point on the sun’s equator travels at four times the rotational velocity of one on the earth’s equator, but the sun’s attraction of gravity is twenty-seven and one-tenth times that of the earth, so that the piling up of an atmosphere of hydrogen would be considerable, and such depressions would not ordinarily exist there. Similarly, near the sun’s poles we should find a gradual darkening, as is the case; but from five degrees to thirty degrees latitude, the sun, in its rotation, by reason of the inclination of its axis, passes at every point directly beneath the planets, or within their area of control, and here we find the solar spots in their greatest number, size, and intensity. These sun-spots cross the face of the sun in about fifteen days, and vary in development from year to year, having a cycle of 11.11 years from maximum to maximum. They also have a long cycle of about fifty-six years. (See article “The Sun,” in Appleton’s Cyclopædia.) “Wolf, in 1859, presented a formula by which the frequency of spotsis connected with the motions of the four bodies, Venus, the earth, Jupiter, and Saturn. Professor Loomis, of Yale College, has since advocated a theory (suggested by the present writer [Proctor] in 1865, in ‘Saturn and his System,’ page 168, note) that the long cycle of fifty-six years is related to the successive conjunctions of Saturn and Jupiter. But the association is as yet very far from being demonstrated, to say the least.” Should such fact be established, an explanation for it will be found in the direct impact of the condensed electric currents from several planets approaching conjunction, and raising a portion of the sun’s atmosphere suddenlyto a higher temperature and volatilizing an abnormal proportion of the semi-vaporous metallic core beneath. This would form an upburst piling the intensely heated faculæ up on the sides and revealing the relatively darker masses of cloud beneath, the cooler supernatant hydrogen pouring in from the upper layers to fill the returning void. This is precisely what is seen in such spots and their surrounding disturbances. In the article “The Sun,” above quoted, we read, “Mr. Huggins has found that several of the absorption bands belonging to the solar spectrum are wider in the spectrum of a spot, a circumstance indicative of increased absorption so far as the vapors corresponding to such lines are concerned …. Near the great spots or groups of spots there are often seen streaks more luminous than the neighboring surface, calledfaculæ. They are oftenest seen towards the borders of the disk.” This writer also describes “luminous bridges across spots which sink into the vortex and are replaced by others of the numberless cloud-like forms from one hundred to one thousand miles in diameter, the brilliancy of which so greatly exceeds that of the intervening spaces that they must be recognized as the principal radiators of the solar light and heat.” The apparent retardation of the spots most distant from the sun’s equator may also be partially, at least, explained by planetary currents of electricity, as the equatorial atmosphere is deeper and more likely to carry forward such vortices when formed, while the planets act more directly on the sun’s mass beneath their direct influence.Let us consider this retardation of sun-spots somewhat more in detail. Take, for example, the case of a large planet at such orbital position that its direct line of electrical impact will penetrate the photosphere at (say) seven degrees north solar latitude, which is about fifty-two thousand miles from his equator. During its annual revolution this planet will traverse, with its line of energy, every point of the sun’s surface down to seven degrees south latitude and back again to its initial point, thus tracing a close spiral around the sun for fourteen degrees, or about one hundred and four thousand miles in width. The centrifugal force of the solar rotation piles up the photosphere and the chromosphere around the sun’s equator, precisely as our atmosphere is piled up around our own equator. If the planet be a large one (for distance has but little to do with these electrical currents at planetary distances, in which they differ entirely from light, heat, and gravity), or if there be two planets nearly in conjunction, the body of the chromosphere and the surface of the photosphere will gradually become highly heated, for currents of electricity, of themselves, do not directly heat the solar core any more than a like current heats the under carbon of an arc lamp, the high temperature in both cases being altogether due to the incandescent heat of the interposed arc or envelope. Faculæ of intense brightness will then appear upon the photosphere, and these will be driven forward and also outward in the direction of the higher latitudes, producing an oblique forward movement from difference ofrotational speed at different portions of the sun’s surface. Similar phenomena are constantly observed on the surface of the earth in the generation and behavior of cyclones and other atmospheric disturbances. They may be compared to the wake of a vessel anchored in a strong tide-way. These faculæ will slowly raise the temperature of the surface of the sun’s core beneath to the point of eruptive volatilization, and particularly so if the planet is receding from, instead of advancing towards, the solar equator. At some point in advance of the line of planetary energy an eruption of volatilized metals will suddenly occur, first thrusting up a vast area of the photosphere and then bursting it asunder, which will drive these ruptured masses with enormous speed forward and obliquely outward from the equator. Such faculæ (see Proctor’s “Light Science”) sometimes reach a velocity of seven thousand miles per minute, while the sun’s rotational movement at the equator is less than seventy miles per minute. This sudden eruption will be almost immediately succeeded by great expansion and consequent fall of temperature, so that within a few hours the heavy volatile metals begin to condense and rapidly recede into their crater, and the faculæ in front and at the sides will now stream inward to occupy this vacuum with constantly accelerated velocity, pouring over the edges like the rush of waters at the Falls of Niagara. As they sweep downward over the inner rim of the funnel, these streams of faculæ will glow with increased whiteness, and appear tobe sharply cut off at their inner ends; but this is only apparently so, and is due to the position of the observer, who looks almost directly downward upon these descending streams. It is for the same reason that the faculæ appear more brilliant when near the borders of the solar disk (see page 109). Any good view of a sun-spot when analyzed will show the streams of faculæ thus pouring inward, and they are among the most peculiar and conspicuous phenomena to be observed. The drawings of Professor Langley, reproduced in thePopular Science Monthlyfor September, 1874, and July, 1885, are particularly striking in their illustration of these effects, though their significance and interpretation were not then at hand.Analysis of a typical sun-spot. Intersections of lines drawn between AA and MM, CC and MM, show state of active eruption; DD, inflowing faculæ pouring downward over the rim; PP, the same; OO and BB a floating bridge, partially completed, supported by the uprush, and along the line NN torn asunder, and upward into plumes and sprays. The general surface shows the mottlings and faculæ. The partial formation of a loop is shown at XX, YY. The line EQ represents the sun’s equator; fromreartofront, the direction of solar rotation. The line of planetary impact is in rear.But while these heavy metallic vapors so rapidly condense and subside in the forward or initial portion of the sun-spot under observation, new depths of intensely-heated faculæ are generated behind, and these operate with renewed energy upon the fresh surface of the solar core in rear of the original seat of eruption; so that each sun-spot, while in an active state, will exhibit two entirely distinct aspects, the forward portion of the crater in a state of rapid condensation and subsidence of the recently erupted metallic vapors, and with inflowing streams of incandescent hydrogen from the front and sides, and the rear portion of the crater up to its rearward wall, and even streaming forth from beneath it, in a state of violent eruption. The large volcanic craters of the Hawaiian Islands exhibit similar partial eruptions and subsidences progressingsimultaneously in the same depths. The sudden formation of the great incandescent loops and plumes to which Professor Langley calls especial attention, and which have hitherto been so perplexing, can now be readily understood and explained. If one of these inflowing streams be carried partially down into and across the crater, and then caught, in its advance, by the uprush in the central or rear portions of the cavity, it will be at once swept upward alongside the ascending eruption,and either scattered at its forward extremity into sprays and plumes, or else thrown forward bodily in the form of a more or less complete loop. In a sun-spot fifty thousand miles in diameter, such a loop, having a long diameter of twenty thousand miles, if we give a speed to the faculæ of seven thousand miles per minute, would be formed in about seven minutes, during which the sun-spot would itself have advanced less than five hundred miles across the face of the sun. The luminous bridges which form so suddenly across portions of the crater may be explained in a similar manner: they are streams of faculæ floated on the nearly balanced uprush of metallic vapors from beneath.Retardation of sun-spots by continuous development to the rear, and recession in front, as the sun rotates on its axis. The short arrows represent lines of planetary energy; the long arrows show the direction of the sun’s rotation.The dark inner disk represents the solar core, the white circle the photosphere, the mottled area the chromosphere and faculæ, and the dark outer ring the corona. Loops and tufted sprays are shown, caused by inflowing faculæ in front, caught by the uprush of active portions of the sun-spot towards rear.It will thus be seen that a sun-spot is not merely a fixed eruption, like a volcano, but rather a continuous series of eruptions, like a line of activity following, for example, the great terrestrial volcanic curve which extends up the western coast of America, across the Pacific Ocean and Asia, and into Central and Southern Europe, for during its progression its scene of action is constantly being shifted to the rear; it is like a furrow cut by a plough, in which the upturned sod is constantly falling in at one end of the furrow while the plough is cutting a new furrow at the other, except that in this case the plough is relatively fixed overhead, and the field itself passes along beneath it. Consequently, the center of activity of a sun-spot is only in its rear portions, generally considered, and the whole sun-spot is gradually retreating, by successive filling up in front and opening out behind, fartherand farther to the rear,—that is to say, to the east,—so that retardation relatively to the rotational advance of the photosphere necessarily ensues.But when the sun-spot is developed upon or near the equatorial line this retardation is not so considerable, for the deeper layers of the photosphere in those regions are slower to act and require greater energy to affect them, so that all except deep and violent eruptions fail to show themselves at the surface at all, and the heated faculæ are carried directly forward along the surface of the equatorial swell, so that the center of activity is driven forward more rapidly than in the higher latitudes, and the rate of progression is more nearly coincident with that of the photosphere. But if these facts are correctly stated and explained, we may have to revise our calculations of the sun’s rotational period, for retardation to some extent must occur in all cases, if in any.A sun-spot, we thus perceive, is an elongated wave or ridge of eruption along the rotational direction of the sun’s body. Why, then, it may be asked, is not this line of eruption continuous entirely around the sun? For the same reason, it may be answered, that our own cyclones are not continuous, though caused substantially in the same manner, and that volcanic eruptions only occur at long intervals, though the forces at work are continuous. Lowering of temperature follows swiftly after eruption, and as the deeper structures of the solar nucleus become gradually affected, instead of volatilization of the outer layers of the surface, we will have diffused gaseous expansion of large portions,and finally of the entire solar mass, which cannot as a whole be volatilized by any conceivable planetary energy. We see these operations exemplified in heating a bar of copper in a Bunsen flame; the latter first turns green from surface volatilization of the copper, but as the heat is communicated to the deeper structures the green flame disappears, and the whole additional heat goes to raise the temperature of the mass.These processes in the sun are thus seen to be self-compensatory in their nature. They are the means provided to distribute the restricted areas of abnormally heated photosphere over the solar surface, and finally to cause the absorption of the whole excess of heat in the sun’s central mass. The balance is so evenly maintained, however, that, were all the planets equally distributed with reference to the sun’s surface, such sun-spots would be the exception and not the rule, and their distribution would be equal and constant; but, as the planets continually change their positions with reference to the sun and to each other, only by some such provision of nature could the internal structure of the sun be maintained without serious derangement, or, indeed, final disruption. So nature distributes her stores of heat upon the earth. These beautiful self-compensations we shall find suddenly appearing, as we advance, in all parts of the field of astronomical research.It may seem like temerity to advance statements so positive and specific as to the cause, constitution, and progression of sun-spots, in the absenceof any considerable accumulation of observations to sustain them, but the few examples which we have noted are in accordance with these views, and when attention is once called to the basic principles on which they depend, observations will doubtless be made in abundance to prove or disprove what has been here stated. The mere fact of a differential rate of advance among sun-spots, as they pass across the solar face, of itself demonstrates that the active causes of these phenomena must be extra-solar, and if so, their only possible dynamic source must be looked for in the planets, and the remaining conclusions will of necessity follow as a corollary. We may even, by merely examining an accurate drawing of a sun-spot, determine its position and direction upon the solar sphere from which it was delineated by its lines of active eruption and influx of faculæ, and also whether it be a new spot or one which has passed entirely beyond its active stage and is about to finally disappear.As for the faculæ which striate the photosphere, the mottlings and so-called “willow-leaves,” any one who will quietly gaze downward upon the turbid surface of the Mississippi or other similar river, in mid-channel, will see plenty of such faculæ: the river is full of them. The heavier, intermingled clay, slowly subsiding, is caught up in the turmoil beneath the surface and swept upward in elongated ovals and eddies, the larger swells nearly colorless, and others of all shades of ochre and yellow, and the whole as richly mottled, sometimes, as the variegated pattern of a Persian carpet. If we substitutefor the subsiding clay the rapidly sinking heavy metallic vapors, and enlarge the scale from the dimensions of the river to those of the sun, we will have the mottled solar surface with its kaleidoscopic changes, the so-called “willow-leaves,” and the faculæ in all their glory. A careful study of the sun will show most clearly that only in some such explanation as the present view affords can a rational basis for its varied phenomena be found.Illustrating complex lines of planetary electrical energy produced by inclination of sun’s axis.—A B, A′ B′, plane of planetary orbits.Upper figure shows sun’s axis inclined laterally; lower figure, from front to rear, and at right angles to former.C, chromosphere; E E, solar equator; A B, A′ B′, lines of planetary electric currents; F, latitude covered by vertical position of planets, 14° in width; P P, sun’s axis.If the sun’s equator were coincident with the plane of the planetary orbits, it is obvious that all the planetary energies would be directed, whatever the position of the planets around the sun, immediately upon this equatorial great circle, and that, at each revolution upon his axis, corresponding nearly to our calendar month, the same part of his sphere would be exposed to these direct currents, so that the intensity would be, in its aggregate, nearly a constant quantity. But, by reason of the sun’s axial inclination of seven degrees to the plane of the planetary orbits, a far more complex and important condition of affairs ensues. It will be seen at once that the plane of the planetary orbits intersects the sun’s equator at opposite sides, and that, from a minimum of nothing, this line reaches a maximum, twice in each circumference, of seven degrees, one north and the other south of the equator, and that this arc of fourteen degrees, thus traversed by every planet in its orbital rotation around the sun, measures more than one hundred thousand miles from north to south upon the solar surface, nearly one-half the distance which separates theearth from the moon. If all the planets were in conjunction or nearly so, on one side of the sun, for example, and in the vertical plane of the sun’s axis, they would continue to deliver their electrical currents with their greatest intensity upon a single point of his surface fifty-two thousand miles north of his equator, while the opposite point, one hundred and four thousand miles distant, would be unaffected by any direct currents at all. Conversely,if in conjunction on the opposite side of the sun, they would continue to deliver these currents upon a corresponding point fifty-two thousand miles south of the equator; but if in conjunction in the vertical plane transverse to the sun’s axial inclination, these currents on either side of the sun would be delivered directly upon the solar equator. The importance of this will be understood when it is considered that for many of our years such planets as Jupiter and Saturn must continue to direct their currents upon a very slowly changing point of the sun’s surface, by reason of their vast annual rotational period, while with the earth and the interior planets these various points are struck with ever-increasing rapidity as the year decreases in length with the different planets, the earth, Venus, and Mercury. There is a solar equinoctial, so to speak, just as there is a terrestrial equinoctial in which the sun crosses the line twice each year, and the meteorological disturbances faintly shown on the earth at such times are vastly increased on the sun, and rendered far more complex by the interaction of many planets upon the sun, instead of a single sun upon each planet. While our equinoctial has to do with gravity and light and heat, and probably magnetism, the solar equinoctial deals with the vast electrical streams which feed its fires and set it boiling with furious energy, first at one point, then at another, until the increment has been absorbed and adjusted, and thus equalized throughout his mass. What a new interest this must arouse in our study of sun-spots, faculæ, prominences, sun-storms,and the vast panorama of solar action hung up before our astonished eyes! A new world here awaits its Columbus.But not only the planets thus gather, so to speak, electricity for the sun’s support from space; the moon also must do its part, as it rotates in the same manner, subject to the sun, and has its own motion through space. But an examination of the moon shows no atmosphere and no aqueous matter visible to us, and also the singular fact that it constantly presents one side only to the earth. R. Kalley Miller, in his “Romance of Astronomy,” article “The Moon,” says, “After an elaborate analysis, Professor Hausen, of Gotha, found that it could be accounted for only by supposing that the side of the moon nearest us was lighter than the other, and hence that its center of gravity was not at its center of figure, but considerably nearer the side of it which is always turned away from us. He calculates the distance between these centers to be nearly thirty-five miles, evidently a most important eccentricity, when we remember that the radius of the moon is little over a thousand miles. It must have been produced by some great internal convulsion after the moon assumed its solid state; but the forces required to produce this disruption are less than might at first sight appear necessary, owing to the fact that the force of gravitation and the weight of matter are six times less at the moon than with us.” Those who are fond of the so-called “Argument of Design” will be gratified to learn that, if the moon had a rotation upon its ownaxis similar to that of the earth, all life—past, present or future—would have been impossible on that satellite or planet; and that, on the contrary,—provided she always turns the same side of her surface to the earth,—it is quite possible that air, water, and life may exist, or may have existed, on the opposite side of the moon, but not otherwise. In fact, air and water must now exist on the opposite side; and, since her whole supply will thus be condensed upon half her surface or less, even with her small force of gravity, it may be quite sufficient in quantity and density for the support of animal, vegetable, or even human life. By reason of this difference in the lunar center of gravity, the side presented to the earth in physical position is similar to the summit of a mountain upon the earth’s surface two hundred miles high, and surely we would not expect to find much air or water or life at that altitude. But the opposite side would resemble a champagne country at the foot of this enormous mountain, and might be well fitted for human existence. Now, we know that similar electricities repel each other, and air or gases charged with similar electricities are equally self-repellent. Professor Tyndall, in his “Lessons in Electricity,” says, “The electricity escaping from a point or flame into the air renders the air self-repulsive. The consequence is, that when the hand is placed over a point mounted on the prime conductor of a good machine, a cold blast is distinctly felt …. The blast is called the ‘electric wind.’ Wilson moved bodies by its action; Faraday caused it to depressthe surface of a liquid; Hamilton employed the reaction of the electric wind to make pointed wires rotate. The wind was also found to promote evaporation.”Fig. 1, mutual repulsion of similarly electrified pith-balls; 2, the electrical windmill, atmospheric repulsion; 3, repulsion of a flame by electricity; 4, electrical distribution around an oval conductor; 5, mutual attraction of opposite electricities; 5a, mutual repulsion of similar electricities; 6, mutual repulsion of electrospheres of earth and moon; 7, mutual repulsion of electrospheres of sun and comet.While electrical repulsion is doubtless analogous to, and correlative with, the attraction of gravitation, this force, and even gravity itself, has been sometimes interpreted as derived from the mutually interacting molecules of space itself. We may even learn somewhat of how such repulsions of similar and attractions of opposite electrospheres might occur. We constantly speak of positive and negative electricity as though these were different fluids, but such expressions are employed only in the same manner as the analogous terms, heat and cold. We know, of course, that cold is the relative absence of heat, the dividing line being not a fixed, but a constantly changing one, so that one body is cold to another by reason of relative, and not absolute, deprivation of heat. It is well known, however, that cold, which is purely a negative state, manifests the same apparent radiant energy as heat. A vessel near an iceberg is exposed to a wave of cold, precisely as of heat from a heated body at the same distance. This, of course, is due to abstraction and not to increment. All space being occupied by attenuated matter in a state of unstable electrical equilibrium, as we say, which simply means a condition ready to be raised or lowered in tension by absorption from or into outside media, all concrete bodies floating in that space must have an electrical potentialeither equal to, or higher, or else lower than that of their surrounding space. A solitary body in space, if we can conceive of such, in either a higher or lower state of electrical tension, would be drawn upon from all sides to equalize the distribution and restore the general average. But if two bodies occupy the same field, and are widely different from each other in electrical potential, one higher and the other lower than that of space, this distribution will be towards each other, and must be manifested by mutual attraction. But if, on the contrary, these two bodies are both equally higher or lower than the spatial average, they have nothing to give to each other, but have this difference to give to or receive only from outer space, and hence they will be drawn apart or, as we say, mutually repelled. The case is similar to what we see in the case of bodies of water at various levels. Suppose there be a lake of a fixed level, and communicating with it and with each other, by open channels, two ponds of water occupying an island in the middle of the lake. If one of these ponds be higher in level and the other lower than the lake, their waters will rapidly converge, the higher flowing into the lower; but if both are at the same level, and higher than the lake, they will flow apart into the lake. Or, if both are at the same level, and lower than the lake, the water of the latter will equally flow from outside into both ponds, and their waters will still be held separate from each other. The analogies of these various levels may be pursued to any desired extent, as electrical tensionsfind their most exact analogies in the pressures of bodies of water at different levels and of different quantities, and these analogies are those most constantly used in the interpretation of such electrical phenomena.The great electrical activity of the electrospheres of the earth and moon, while they discharge their tremendous currents directly into the sun, at the same time must cause their similarly electrified atmospheres to mutually repel each other, while gravity continues to operate to maintain the earth and moon at their fixed distances from each other, and to retain their gaseous envelopes around their own bodies. The result must be that these similarly electrified atmospheres repel each other with a force proportioned to their masses of atmosphere and the intensity of the electricities of each. The moon’s axial rotation being completed but once in twenty-eight days, and that of the earth once in each day, and the moon’s mass and volume being so much less than those of the earth, whatever of electrified air or moisture she may have (and she must have both, proportionate to her attributes) would have been driven as by a cyclone to the opposite side of the moon and there retained. Now, with an atmosphere and water only on one side of the moon, and that the side opposite the earth, it is obvious that a rotation on her axis at all resembling that of the earth would carry every part of her surface, at each complete rotation, from a region of air and moisture into one deprived of both, and in such a condition she would of necessitybe deprived of both life and its possibility; hence, as the laws of nature compel the lunar atmosphere and moisture to reside permanently on the side always opposite the earth, a co-ordinate arrest of the moon’s axial motion with reference to the earth could alone compensate for such a state of things, and, curiously enough, we find as a solitary exception, compared with the planets, that such is the case. The moon unquestionably has both atmosphere and water on its opposite side. In his recent work, “In the High Heavens,” Professor Ball reviews the physical conditions of the other planets as possible abodes of life. He pronounces against the moon because night and day would each be a fortnight in length; but this is surely no objection, for even in Norway and Greenland such nights and days are not uncommon at different seasons, and thousands of human beings, even as at present constituted on earth, spend their lives there in content and happiness. That the moon also would be terribly scorched by the long day and frozen by the long night does not necessarily follow, for the atmosphere of Mars, that author says, “to a large extent mitigates the fierceness with which the sun’s rays would beat down on the globe if it were devoid of such protection.” As the moon’s opposite face must have a double quota both of atmosphere and clouds, the difficulty will be correspondingly less than on Mars; and as for the “lightness” of bodies on the moon, they would probably get along quite as well as mosquitoes and like “birds of prey” in the marshes along our coasts. The author refersconstantly toourbodies; for example, “Couldwelive on a planet like Neptune?” No, we could not; we would be dead before we got there. Nor couldwelive in the bark of a tree, or at the bottom of the ocean, or in a globule of serum; but living beings are found there nevertheless. The principle is that wherever life is possible there we may expect to find life; and surely life is, or has been, or will be possible, not only on the moon, so far as our knowledge of physical conditions can go, but also on some of the other planets. Of course each planet has its life stage, but this applies not only to the earth, but to all the other planets as well, and not only to the planets of our own system, but to those of all other solar systems. Each has had, or will have, its stage in which life is possible, and these planets may be like human habitations, in which whole races at times migrate from one home to another. There is no conceivable reason why this may not be the general law of creation, and every analogy leads us to believe that it is so.It has been recently announced that, from telescopic observations, the atmosphere of Mars must be at least as attenuated as that among the highest mountainous regions of the earth, if this planet has any atmosphere at all. That it must be far less dense than that of the earth at sea-level is obvious, for the mass and volume of Mars are very much less than those of our own planet; but that Mars is devoid of a gaseous envelope or atmosphere is contrary to what we know of all sidereal physics. The sun, the fixed stars, the comets, the nebulæ, andeven the meteorolithic fragments which fall upon the earth, all show the same elementary chemical constitution as the earth itself, and we cannot believe that Mars alone is differently constituted from every other body we have been able to examine. We have direct evidence, on this planet, of polar snows and their melting away under the sun’s heat; we see the apparent areas of sea and land; it has its moons as the earth has hers, and exhibits all the characteristic phenomena of the earth and other planets. All sidereal bodies that we know of, except, perhaps, our moon, which exception we have fully accounted for, are found to be surrounded by gaseous envelopes or atmospheres of some sort. The sun, the fixed stars, the nuclei of comets, the condensing nebulæ, the planets Jupiter and the earth, which are those under our most direct observation, and even the meteorites, when examined, reveal the presence of many times their own volumes of independent atmospheric gases; and whatever may be the theory of the origin or development of Mars, it must have been subjected to the same influences, the same environment, and the same processes of creation as those of our solar system generally; and that this body alone should possess no gaseous envelope—for the denial of atmosphere denies, at the same time, the presence of any or all surrounding gases—is quite incredible. Only the most positive, direct, and long-continued proofs of such fact could be accepted, and even then the history of all scientific progress shows that what are believed to be facts themselves fluctuate like fancies till, bytheir accumulated force, they solidify into universally accepted demonstration. The fact, moreover, that the atmospheres of the smaller planets are more attenuated than our own and those of the larger ones denser has no bearing, in itself, on the probability of the existence of life on these other planets, for in our own atmosphere oxygen, which is the efficient element, is diluted with four times its quantity of inert nitrogen. These proportions doubtless vary largely in other atmospheres, so that the oxygen may be much richer in some and far poorer, relatively, in others. The mere fact that the presence of nitrogen, probably, and aqueous vapor, certainly, depends on the gravity of the mass of each planet, while the oxygen is due to electrolytic decomposition induced by the combined volume, mass, and rotation, and other causes,—such as the axial inclination of such planets, for example,—renders these variations in the constitution of planetary atmospheres a certainty. As Mars has a diameter much more than one-half that of the earth, and a diurnal rotational period nearly the same, while his mass, which controls the action of gravity, is only about one-ninth that of the earth (see Appleton’s Cyclopædia), it is obvious that his oxygen-gathering power, compared with that for accumulating nitrogen and aqueous vapor, is much higher than that of the earth, and we should expect to find there an attenuated atmosphere very rich in oxygen, and with a relatively smaller proportion of aqueous vapor, or even water, on his surface. Such seem to be the facts as far as observed.In operating an electric machine the strength of the current is directly proportionate to the speed of rotation,—that is to say, to the velocity of the generating surface; for example, of the Wimshurst induction machine it is stated (page 63, “Electricity in the Service of Man”), “These four-and-one-half inch discharges take placein regular succession at every two and a half turnsof the handle.” It is also a well-established law of electrolysis that “The amount of decomposition effected by the current is in proportion to the current strength.” Professor Ferguson (“Electricity,” page 225) says of the voltameter, an instrument devised by Faraday, and used for testing the strength of currents by the proportionate decomposition of acidulated water, “Mixed gases rise into the tube, andthe quantity of gas given off in a given time measures the strength of the current.” Roughly estimating the diameter of Mars at five-eighths, the surface velocity at three-fifths, and the mass at one-ninth those of the earth, this planet should have an atmosphere containing about sixty per cent. of oxygen and forty of nitrogen, with a barometric pressure at sea-level of about six and one-half inches of mercury. This would be an excellent atmosphere,—about equal in its quota of oxygen for each respiration to that of the higher areas of Persia, a great country for roses. The aqueous vapors lying low and near the surface would serve as a vaporous screen to concentrate and retain the sun’s heat and retard radiation from that planet. Nothing in particular seems to be the matter with Mars.On the contrary, the mass of Jupiter is so great, and his attraction of gravity so powerful, that it is only by his exceedingly rapid diurnal rotation (once in less than ten hours) that it is possible for him to accumulate any effective percentage of oxygen at all. But there is certainly plenty of water there.We may approximately compute, in general terms, the proportion of oxygen in the atmospheres of the other planets in the same way. Neptune, it is true, is so far distant from the sun that the solar orb only “appears about the same magnitude as Venus when at its greatest brilliancy, as viewed from the earth,” but we must not forget that “theintensityof the sun’s light would be more than ten thousand times greater than that of Venus” (Professor Dunkin, in “The Midnight Sky”). Unless the moon gathers a portion of the earth’s oxygen (the planetary satellites, like Saturn’s rings, thus constituting in their rotations a constituent part of the planets themselves), the percentage of this gas in her atmosphere must be exceedingly small, for her axial rotation has a period of a whole lunar month, being the same as that of her revolution around the earth as a center.The absence of apparent atmosphere and moisture from thevisiblelunar surface has already been mentioned and explained. The means by which this fact has been approximately determined are described by Professor Dunkin, in “The Midnight Sky,” as follows: “Among the many proofs of the non-existence of a lunar atmosphere, it maybe mentioned that no water can be seen; at least there is not a sufficient quantity in any one spot so as to be visible from the earth. Again, there are no clouds; for if there were, we should immediately discover them by the variable light and shade which they would produce. But one great proof of the absence of any large amount of vapor being suspended over the lunar surface is the sudden extinction of a star when occulted by the moon. The author has been a constant observer of these phenomena, and, though his experience is of long standing, he has never observed an occultation of a star or planet,especially at the unilluminated edge of a young moon, without having his conviction confirmed that there is no appreciable lunar atmosphere …. Professor Challis has subjected the results of a large number of these observations to a severe mathematical test, but he has not been able to discover the slightest trace of any effect produced by a lunar atmosphere.”In Appleton’s Cyclopædia, article “The Moon,” it is stated that “Schröter (about 1800) claimed to have discovered indications of vegetation on the surface of the moon. These consist of certain traces of a greenish tint which appear and reappear periodically; much as the white spots covering the polar regions of Mars …. As we are able, under the most favorable conditions, to use upon the moon telescopic powers which have the effect of bringing the satellite to within one hundred and fifty to one hundred and twenty miles of us, we should doubtless notice any such markedchanges on her surface as the passage of the seasons produces, for example, on our own globe.” Very recently (August 12, 1894), it has been stated, Professor Gathmann has observed a peculiar green spot about forty by seventy miles in area near the crater of Tycho Brahe, “on thenorthwestern edgeof the satellite’s upper limb,” which had disappeared twenty-two hours afterwards.We understand, of course, that the moon’s librations, by the variation of position of the lunar body, enable us to see, at times, around the edge of this satellite somewhat, so that, instead of observing only one-half, we can in this way see nearly six-tenths of her surface, but not at the same time, of course. When the moon is dark it occupies a position between the earth and the sun, and only its opposite face is illuminated. In this position the attraction of solar gravity and the attraction of the electrically opposite solar electrosphere both accumulate their forces upon the moon’s atmosphere in the same line as the repulsion of the earth’s similar electricity, so that the lunar moisture and atmosphere are, at this part of her subordinate orbit, most powerfully forced away from the direction of the earth. As the moon now proceeds towards her first quarter, the terrestrial repulsion drives her atmosphere radially outward, while solar gravity and electrical attraction tend to hold it in the direction of the sun. The result will be an electrospheric libration, so to speak, and the moon’s atmosphere and moisture will be carried around towards its illuminated face and, to someextent, will overlap the area of terrestrial repulsion. But as the moon advances this will gradually diminish, soon cease, and finally be reversed as it again approaches darkness. We can now understand why the green surface, if it really was due to vegetation, appeared along thelunar marginat the time described above, and also that the observation of planetary occultations “at the unilluminated edge of the young moon” was the very worst part of the moon and its orbit in which to look for air or moisture; as the sun’s influence is then directlyaway fromthe unilluminated surface of the moon, and his “pull” would have, in fact, still further denuded the very portion most persistently examined, and where this absence of atmosphere wasespeciallynoted.When considering the transference of energy from the peripheral regions of the solar system to the center, its conversion there into a new form of molecular force, and its subsequent distribution, we find a curious and instructive parallel in the action of the reflex nervous system of animal life. This system is one in which the brain or other conscious center of nerve-energy takes no part. Tickle the foot of a child, for example, and its whole muscular system is thrown into uncontrollable convulsions of laughter. Here an exciting contact with the terminal filaments of the afferent or sensory nerves is rapidly carried into the local nerve-center of this part of the system,—that is, the sensory column of the spinal cord. This center of ganglionic nerve-matter lies directly against the correspondingmotor mass, both freely communicating with each other. The sensory current passing into its central ganglion undergoes some peculiar change of character, probably one of intensification, such as is observed in the action of the condenser of an electrical machine, through which sensory ganglion, thus raised in potential, it passes to the motor ganglion adjacent, where it is instantly transformed into an entirely different form of energy. The sensory character has now entirely disappeared, and it has been converted into and is flashed forth as motor energy to the different muscles of the body, which are immediately contracted, the violent molecular motion of the fibres being at once converted into muscular motion in mass. The changes are entirely analogous to those we see in the different conversions of energy in our solar system. Considering the surface of the body as a planetary electrosphere, it is acted upon by excitation from without; currents of energy are engendered, which are at once transmitted to the sensory ganglion, corresponding to the hydrogen atmosphere or electrosphere of the sun; intensification of action here ensues, the current passing through this ganglion or atmosphere into the solar body itself, which corresponds to the motor ganglion; both ganglia are now highly excited; the electrical force is converted into the radiant molecular motor energy of heat and light in the sun and muscular excitement in the body, and these are flashed forth and find scope for their action within the body of the subject or upon the surface of the planets, whichlie, like the muscular structure of the body, within the genetic electrosphere where, acted upon from without and by agencies entirely external, moving contact has induced the primary molecular action, which was then instantaneously transferred to the center, there converted into another form, that of motor energy, and thence sent forth to produce action in the muscles of the body in the one case, and in the other upon the planetary bodies and their satellites and other structures which occupy surrounding space.

CHAPTER IV.THE SOURCE OF SOLAR ENERGY.

The remarkable resemblance between the mode of operation and effects of these electrical induction machines and the vast rotating electrosphere of the earth must be at once apparent. The operation is precisely the same, and the results must,pari passu, be substantially similar. We need not seek for precise parallelism of structure, because these machines themselves, it has been shown, widely differ in structure among themselves. But the almost infinitely more vast terrestrial electrosphere, which cannot be less than ten thousand miles in diameter, and perhaps much more (if we may form an opinion from the relative magnitude of the field of action of the hydrogen envelope which constitutes the solar electrosphere), rotating in the attenuated vapors of space, among which vapors that of water plays a most important part, and which vapors constantly impinge with various disturbances of contact against the more and more attenuated layers of the terrestrial atmosphere, and which gradually, from within outward, less and less partakes of the earth’s rotation until, finally, its rotatory movement is lost in the vast ocean of space, establishes the certainty that enormous quantities of electricity must there be disengaged, preciselyas in the machines which we have described, and to learn the potential or active pressure of this electricity we have only to consider the fact that we find a rise so rapid, as we ascend through our atmosphere, that the potential increases by from twenty to forty volts for each foot. That these currents are transmitted to the sun without appreciable resistance we already know, and that they are there transformed into light and heat we can, from the previously cited experiments, see.But it may be urged that the resistance of such attenuated vapors in space, and the generation of electricity in such quantities, would inevitably retard and finally destroy planetary motion. The sufficient answer to this is found in the consideration that the same facts must exist under any possible mode of organization of our solar system, and that such interference, besides, must have absolutely prevented its formation at all, if such were the case. All the matter of our planetary system together is only one seven-hundred-and-fiftieth that of the sun; if this were added to the sun’s bulk it would but slightly enlarge it. But all this solar and planetary matter together, if distributed over the space occupied by our planetary system,—and, by the nebular hypothesis of the organization of our solar system, this is requisite,—and having an axial diameter one-half that of its equatorial (see Proctor’s “Familiar Essays on Scientific Subjects,”—“Oxygen in the Sun”), would have had a density of only about one four-hundred-thousandth that of hydrogen gas at atmospheric pressure. This nebular mass musthave had a diameter at least sixty times that of the distance of the earth from the sun and a depth of thirty times its distance. That this enormous mass of attenuated matter should ever have been made to rotate as a whole by any force of attraction, repulsion, or rotation, with a tenuity so great that, if measured by an equal volume of hydrogen gas,—the lightest substance known to us,—it would have furnished material for four hundred thousand such systems as ours, presupposes a resistance so slight that the planets themselves, when coagulated out of such a mass, could never in any conceivable time exhibit retardation from such a source; and we know to a certainty that such attenuated vapors do exist in space, for electricity cannot be transmitted through a vacuum, and it is transmitted with perfect freedom between the earth and the sun. But it may be said that the laws were then different. If they were different then, they are doubtless different now. If, on the other hand, we assume that the bodies of which our solar system is composed were simply aggregated into concrete masses from meteoric dust, the difficulty is not lessened; for if the resistances to their operation now are such as to perceptibly retard their motions, they must have operated still more powerfully to originally prevent them; while, if hurled forth by an almighty fiat, complete from the hand of creative energy, the same force which impelled them forward must have also established the laws under which they now move.It is calculated that our earth must be losingtime, by tidal retardation, at the rate of one-half the moon’s diameter in each twelve hundred years (see Proctor, “Light Science for Leisure Hours,”—“Our Chief Timepiece Losing Time”), and that “the length of a day is now more by about one eighty-fourth part of a second than it was two thousand years ago.” Perhaps, however, we may discover that these changes are themselves periodic and increase in cycles to a maximum, and then diminish, as is the case with magnetic, planetary, and stellar variations, and other similar changes, when sufficiently long observed; for while such changes may very well accompany a theory under which our system and all other systems are slowly running down to decay and death, it is entirely incompatible with the primal forces under which theymusthave been originally formed. In other words, if the tides are dragging back our earth without compensation, this dragging back can only come from the oceanic deposit of water on the earth from the aqueous vapors of space which do not partake of the planetary rotation and orbital movement of the earth. But if these can now retard the earth’s motion, they must have originally prevented it in the beginning. This loss of time is, moreover, merely inferential from mathematical computations, and its basis is found in the belief that all the operations of nature are in a slow process of degradation, and the calculated loss itself may be merely theoretical, and not true in fact. Professor Proctor himself concedes the uncertainty of this alleged retardation when he says in the samearticle, “At this rate of change our day would merge into a lunar month in the course of thirty-six thousand millions of years. But after a while the change will take place more slowly, andsome trillion or so of yearswill elapse before the full change is effected.”While the processes of nature are generally believed to be running down, everything is bent to that belief; but the forces of nature must, nevertheless, be uniform and supreme, for it is by these forces that the expected results are to be achieved. That changes occur constantly is inevitable, but the source of these must be looked for in the interaction of original forces, and not in the degradation of systems. There is reason to believe, in fact, that the repulsion of the terrestrial electrosphere by that of the moon may itself be sufficient to counteract such retarding force of lunar gravity, for the tides upon earth are not merely oceanic, but atmospheric, and on the latter the electrical repulsion of the moon must act very powerfully and with directly counteractive effect.Planetary generation and transmission of electrical energy.—A, the planet; B, electrosphere showing circles of gradually diminishing rotation; E, interplanetary space; D, curve of gradually diminishing rotation; F, F, currents of electricity flowing to the sun; S, direction of the sun.Let us now apply the preceding principles to the problem under review. All planetary space is pervaded with attenuated vapors or gases, among which aqueous vapor occupies a leading place. The planets and all planetary bodies, having opposite electrical polarity from the central and relatively fixed sun, by their orbital motions around and constant subjection thereto act as enormous induction machines, which generate electricity from the ocean of attenuated aqueous vapor, each planet being surroundedby an enormous electrosphere, carried with the planet in its axial and orbital movements, the successive atmospheric envelopes gradually diminishing in rotational velocity until merged into the outer ocean of space. As the planets advance in their orbits they plunge into new and fresh fields, and, as the whole solar system gradually movesonward through space, these fields are never re-occupied. These electrospheres, by their rotation, generate enormous quantities of electricity at an extremely high potential,—so high that we can scarcely even conceive it,—and this electricity flows in a constant current to the sun, where it disappears as electricity, to reappear in the form of solar light and heat. These planetary currents also flow towards such other negatively electrified bodies as may exist in space—the comets and fixed stars, for example—in proportion to their distance; for, since resistance is not appreciable between ourselves and the sun, as is also the case with light, so, like light, our electricity must pass outward as well as inward to take part in the harmonious operations of the whole universe. But it should be noted that the distribution of electric energy in the form of currents is quite different from that of light or other radiant energy; for while light is diffused from a center outward through space, electric currents, on the contrary, are concentrated and directed along lines of force to concrete centers of opposite polarity. As a consequence, the intensity of light decreases according to the squares of the distances traversed plus the resistance to the passage of the light itself, while the electric current is only diminished by the resistance of the medium through which it passes. As the light of the sun has a velocity of one hundred and eighty-eight thousand miles per second, and the electric current between the earth and the sun the same, it will be seen that the resistance is practically alike for these two formsof energy. Indeed, the striking resemblance between the ethereal vibrations which constitute light and heat and exceedingly rapid alternating currents of electricity through molecular media may suggest that the transformation of one force into the other is some sort of a “step-up” or “step-down” process, much higher in degree, but of the same character as the well-known analogous electrical transformations used in the arts. It should also be borne in mind that, while theintensityof light diminishes according to the above law, thequantityremains the same, less resistance, as the area covered increases precisely in the same proportion as the intensity diminishes,—that is, in the ratio of squares.Upper figure.—Gradual discharge between two conductors, in partial vacuum.Lower figure.—Sudden electric discharge through the atmosphere, from left to right.Around the earth and other planets gravity attracts the aqueous vapors in increased density, the same as around the sun; but the electric currents passing between the planets and the sun decompose this aqueous vapor into its constituent gases, hydrogen and oxygen. The oxygen is deposited within the positive electrospheres of the planetary bodies, where it mingles with nitrogen to form our atmosphereand those of the other planets. In this float the aqueous vapors condensed from space, which are lighter than air. (See Tyndall, “The Forms of Water:” “It also sends up a quantity of aqueous vapor which, being far lighter than air, helps the latter to rise.”) These aqueous vapors, condensed into clouds and precipitated upon the earth, form our oceans and their affluents. The hydrogen gas disengaged upon the sun’s surface forms a similar envelope, which is penetrated by the planetary electric currents, and is thus highly heated and rendered incandescent; the glowing hydrogen transmits its heat to the sun’s mass within, which is thus raised to, and permanently maintained in, a liquid or densely gaseous state, its metallic constituents being volatilized in part, and these metallic vapors mingle with the lower strata of hydrogen to form the sun’s photosphere, while, above, the glowing hydrogen grows more pure, and finally, at a distance of hundreds of thousands of miles, is merged into the corona, which is composed, in part at least, of cosmical dust rotating around and repelled by the sun, and which shines partly by reflected light, partly by that of the relatively cooler hydrogen, and partly, perhaps, by electrification of its constituents by the powerful currents passing through it. Each of the planetary bodies, large or small, takes its proportionate part in the generation and transmission of electricity, according to its volume, mass, and motion. As an adjunct to this electrical sequence we have learned that any interruption of such currents between the generatorand the receiver will cause the generating apparatus to glow with diffused electrical light, as is the case with the Wimshurst machine already described. When such connection is removed, it is said, “the whole apparatus bristles with electricity, and if viewed in the dark presents a most beautiful appearance, being literally bathed with luminousbrushdischarges.” Such a phenomenon recalls at once the aurora borealis; and when we find this as a sequence of the electrical storm of the first of September, 1859, before described (“at night great auroras were seen in both hemispheres”), and connect with this the persistence of electricity upon insulated surfaces (see “Electricity in the Service of Man,” page 53: “Glass being a bad conductor, the electricity does not spread all over the plate, but remains where it is produced”), we shall inevitably conclude that there was some partial interruption in the current flowing from the earth to the sun at that moment; and if we recall that at that very instant “suddenly a bright light was seen by each observer to break out on the sun’s surface and to travel across a part of the solar disk,” we shall learn that the processes connected with the production of such a bright light will interrupt in part the terrestrial current. We can readily understand that if this bright light exceeded in electrical intensity that due to the earth’s current, it might temporarily reverse the polarity of the afferent current or retard its flow, like the so-called “backwater” of a mill. It would be like attempting to discharge steam at sixty pounds’ pressure into a vessel filled withother steam at sixty-one pounds. Whence, then, came this bright light? Perhaps from the conjoint action of some other planet, perhaps from sudden chemical disassociation beneath the surface, perhaps by the abnormal piling up of depths of transparent glowing hydrogen or other local disturbance.Position of planets with reference to the generation of sun-spots.—S, the sun; S′, axis of sun’s rotation inclined 7° to plane of planetary rotation; A B, C, D, maximum intensity of planetary action; A′, B′, C′, D′, minimum intensity of same.And this leads to the consideration of the uniformity of solar action. The planetary electrospheres will be constant in their operation if the constitution of surrounding space remains uniform; but we shall find reason to believe that there are currents in the ocean of space, as there are currents in our own seas, and electrical generation will necessarily vary when such currents are encountered. The sun itself in such case, however, will become an automatic regulator, for his density being but one-fourth that of the earth, and the spectroscope having shown his chemical composition to a large extent, we know that his mass must be either liquid or vaporous, and perhaps in part both. Such masses readily respond to variations of temperature, expanding as it rises and contracting as it falls. Hence, if a portion of space were reached where the action of the planetary electrospheres was increased by relative increase of temperature in some interstellar “Gulf Stream,” the sun’s volume would expand and compensation be at once established, while, conversely, with diminution of such planetary action, the solar volume would contract and an increased supply from his reserve store be given out thereby. In this way the condensation relied upon to give us heat forseven or seventeen million years becomes a compensating mechanism, self-operative through the most distant cycles of time. We shall also find in such electric currents an explanation of sun-spots. It is not meant that a full knowledge can be obtained of their minute constitution, nor is it necessary; but the equatorial belt of six degrees, nearly free from sun-spots, we can readily understand to be caused—since sun-spots are depressions in the photosphere down to the deeper and denser cloud strata beneath—by the equatorial piling up of the sun’s atmosphere by its rotation. Any point on the sun’s equator travels at four times the rotational velocity of one on the earth’s equator, but the sun’s attraction of gravity is twenty-seven and one-tenth times that of the earth, so that the piling up of an atmosphere of hydrogen would be considerable, and such depressions would not ordinarily exist there. Similarly, near the sun’s poles we should find a gradual darkening, as is the case; but from five degrees to thirty degrees latitude, the sun, in its rotation, by reason of the inclination of its axis, passes at every point directly beneath the planets, or within their area of control, and here we find the solar spots in their greatest number, size, and intensity. These sun-spots cross the face of the sun in about fifteen days, and vary in development from year to year, having a cycle of 11.11 years from maximum to maximum. They also have a long cycle of about fifty-six years. (See article “The Sun,” in Appleton’s Cyclopædia.) “Wolf, in 1859, presented a formula by which the frequency of spotsis connected with the motions of the four bodies, Venus, the earth, Jupiter, and Saturn. Professor Loomis, of Yale College, has since advocated a theory (suggested by the present writer [Proctor] in 1865, in ‘Saturn and his System,’ page 168, note) that the long cycle of fifty-six years is related to the successive conjunctions of Saturn and Jupiter. But the association is as yet very far from being demonstrated, to say the least.” Should such fact be established, an explanation for it will be found in the direct impact of the condensed electric currents from several planets approaching conjunction, and raising a portion of the sun’s atmosphere suddenlyto a higher temperature and volatilizing an abnormal proportion of the semi-vaporous metallic core beneath. This would form an upburst piling the intensely heated faculæ up on the sides and revealing the relatively darker masses of cloud beneath, the cooler supernatant hydrogen pouring in from the upper layers to fill the returning void. This is precisely what is seen in such spots and their surrounding disturbances. In the article “The Sun,” above quoted, we read, “Mr. Huggins has found that several of the absorption bands belonging to the solar spectrum are wider in the spectrum of a spot, a circumstance indicative of increased absorption so far as the vapors corresponding to such lines are concerned …. Near the great spots or groups of spots there are often seen streaks more luminous than the neighboring surface, calledfaculæ. They are oftenest seen towards the borders of the disk.” This writer also describes “luminous bridges across spots which sink into the vortex and are replaced by others of the numberless cloud-like forms from one hundred to one thousand miles in diameter, the brilliancy of which so greatly exceeds that of the intervening spaces that they must be recognized as the principal radiators of the solar light and heat.” The apparent retardation of the spots most distant from the sun’s equator may also be partially, at least, explained by planetary currents of electricity, as the equatorial atmosphere is deeper and more likely to carry forward such vortices when formed, while the planets act more directly on the sun’s mass beneath their direct influence.Let us consider this retardation of sun-spots somewhat more in detail. Take, for example, the case of a large planet at such orbital position that its direct line of electrical impact will penetrate the photosphere at (say) seven degrees north solar latitude, which is about fifty-two thousand miles from his equator. During its annual revolution this planet will traverse, with its line of energy, every point of the sun’s surface down to seven degrees south latitude and back again to its initial point, thus tracing a close spiral around the sun for fourteen degrees, or about one hundred and four thousand miles in width. The centrifugal force of the solar rotation piles up the photosphere and the chromosphere around the sun’s equator, precisely as our atmosphere is piled up around our own equator. If the planet be a large one (for distance has but little to do with these electrical currents at planetary distances, in which they differ entirely from light, heat, and gravity), or if there be two planets nearly in conjunction, the body of the chromosphere and the surface of the photosphere will gradually become highly heated, for currents of electricity, of themselves, do not directly heat the solar core any more than a like current heats the under carbon of an arc lamp, the high temperature in both cases being altogether due to the incandescent heat of the interposed arc or envelope. Faculæ of intense brightness will then appear upon the photosphere, and these will be driven forward and also outward in the direction of the higher latitudes, producing an oblique forward movement from difference ofrotational speed at different portions of the sun’s surface. Similar phenomena are constantly observed on the surface of the earth in the generation and behavior of cyclones and other atmospheric disturbances. They may be compared to the wake of a vessel anchored in a strong tide-way. These faculæ will slowly raise the temperature of the surface of the sun’s core beneath to the point of eruptive volatilization, and particularly so if the planet is receding from, instead of advancing towards, the solar equator. At some point in advance of the line of planetary energy an eruption of volatilized metals will suddenly occur, first thrusting up a vast area of the photosphere and then bursting it asunder, which will drive these ruptured masses with enormous speed forward and obliquely outward from the equator. Such faculæ (see Proctor’s “Light Science”) sometimes reach a velocity of seven thousand miles per minute, while the sun’s rotational movement at the equator is less than seventy miles per minute. This sudden eruption will be almost immediately succeeded by great expansion and consequent fall of temperature, so that within a few hours the heavy volatile metals begin to condense and rapidly recede into their crater, and the faculæ in front and at the sides will now stream inward to occupy this vacuum with constantly accelerated velocity, pouring over the edges like the rush of waters at the Falls of Niagara. As they sweep downward over the inner rim of the funnel, these streams of faculæ will glow with increased whiteness, and appear tobe sharply cut off at their inner ends; but this is only apparently so, and is due to the position of the observer, who looks almost directly downward upon these descending streams. It is for the same reason that the faculæ appear more brilliant when near the borders of the solar disk (see page 109). Any good view of a sun-spot when analyzed will show the streams of faculæ thus pouring inward, and they are among the most peculiar and conspicuous phenomena to be observed. The drawings of Professor Langley, reproduced in thePopular Science Monthlyfor September, 1874, and July, 1885, are particularly striking in their illustration of these effects, though their significance and interpretation were not then at hand.Analysis of a typical sun-spot. Intersections of lines drawn between AA and MM, CC and MM, show state of active eruption; DD, inflowing faculæ pouring downward over the rim; PP, the same; OO and BB a floating bridge, partially completed, supported by the uprush, and along the line NN torn asunder, and upward into plumes and sprays. The general surface shows the mottlings and faculæ. The partial formation of a loop is shown at XX, YY. The line EQ represents the sun’s equator; fromreartofront, the direction of solar rotation. The line of planetary impact is in rear.But while these heavy metallic vapors so rapidly condense and subside in the forward or initial portion of the sun-spot under observation, new depths of intensely-heated faculæ are generated behind, and these operate with renewed energy upon the fresh surface of the solar core in rear of the original seat of eruption; so that each sun-spot, while in an active state, will exhibit two entirely distinct aspects, the forward portion of the crater in a state of rapid condensation and subsidence of the recently erupted metallic vapors, and with inflowing streams of incandescent hydrogen from the front and sides, and the rear portion of the crater up to its rearward wall, and even streaming forth from beneath it, in a state of violent eruption. The large volcanic craters of the Hawaiian Islands exhibit similar partial eruptions and subsidences progressingsimultaneously in the same depths. The sudden formation of the great incandescent loops and plumes to which Professor Langley calls especial attention, and which have hitherto been so perplexing, can now be readily understood and explained. If one of these inflowing streams be carried partially down into and across the crater, and then caught, in its advance, by the uprush in the central or rear portions of the cavity, it will be at once swept upward alongside the ascending eruption,and either scattered at its forward extremity into sprays and plumes, or else thrown forward bodily in the form of a more or less complete loop. In a sun-spot fifty thousand miles in diameter, such a loop, having a long diameter of twenty thousand miles, if we give a speed to the faculæ of seven thousand miles per minute, would be formed in about seven minutes, during which the sun-spot would itself have advanced less than five hundred miles across the face of the sun. The luminous bridges which form so suddenly across portions of the crater may be explained in a similar manner: they are streams of faculæ floated on the nearly balanced uprush of metallic vapors from beneath.Retardation of sun-spots by continuous development to the rear, and recession in front, as the sun rotates on its axis. The short arrows represent lines of planetary energy; the long arrows show the direction of the sun’s rotation.The dark inner disk represents the solar core, the white circle the photosphere, the mottled area the chromosphere and faculæ, and the dark outer ring the corona. Loops and tufted sprays are shown, caused by inflowing faculæ in front, caught by the uprush of active portions of the sun-spot towards rear.It will thus be seen that a sun-spot is not merely a fixed eruption, like a volcano, but rather a continuous series of eruptions, like a line of activity following, for example, the great terrestrial volcanic curve which extends up the western coast of America, across the Pacific Ocean and Asia, and into Central and Southern Europe, for during its progression its scene of action is constantly being shifted to the rear; it is like a furrow cut by a plough, in which the upturned sod is constantly falling in at one end of the furrow while the plough is cutting a new furrow at the other, except that in this case the plough is relatively fixed overhead, and the field itself passes along beneath it. Consequently, the center of activity of a sun-spot is only in its rear portions, generally considered, and the whole sun-spot is gradually retreating, by successive filling up in front and opening out behind, fartherand farther to the rear,—that is to say, to the east,—so that retardation relatively to the rotational advance of the photosphere necessarily ensues.But when the sun-spot is developed upon or near the equatorial line this retardation is not so considerable, for the deeper layers of the photosphere in those regions are slower to act and require greater energy to affect them, so that all except deep and violent eruptions fail to show themselves at the surface at all, and the heated faculæ are carried directly forward along the surface of the equatorial swell, so that the center of activity is driven forward more rapidly than in the higher latitudes, and the rate of progression is more nearly coincident with that of the photosphere. But if these facts are correctly stated and explained, we may have to revise our calculations of the sun’s rotational period, for retardation to some extent must occur in all cases, if in any.A sun-spot, we thus perceive, is an elongated wave or ridge of eruption along the rotational direction of the sun’s body. Why, then, it may be asked, is not this line of eruption continuous entirely around the sun? For the same reason, it may be answered, that our own cyclones are not continuous, though caused substantially in the same manner, and that volcanic eruptions only occur at long intervals, though the forces at work are continuous. Lowering of temperature follows swiftly after eruption, and as the deeper structures of the solar nucleus become gradually affected, instead of volatilization of the outer layers of the surface, we will have diffused gaseous expansion of large portions,and finally of the entire solar mass, which cannot as a whole be volatilized by any conceivable planetary energy. We see these operations exemplified in heating a bar of copper in a Bunsen flame; the latter first turns green from surface volatilization of the copper, but as the heat is communicated to the deeper structures the green flame disappears, and the whole additional heat goes to raise the temperature of the mass.These processes in the sun are thus seen to be self-compensatory in their nature. They are the means provided to distribute the restricted areas of abnormally heated photosphere over the solar surface, and finally to cause the absorption of the whole excess of heat in the sun’s central mass. The balance is so evenly maintained, however, that, were all the planets equally distributed with reference to the sun’s surface, such sun-spots would be the exception and not the rule, and their distribution would be equal and constant; but, as the planets continually change their positions with reference to the sun and to each other, only by some such provision of nature could the internal structure of the sun be maintained without serious derangement, or, indeed, final disruption. So nature distributes her stores of heat upon the earth. These beautiful self-compensations we shall find suddenly appearing, as we advance, in all parts of the field of astronomical research.It may seem like temerity to advance statements so positive and specific as to the cause, constitution, and progression of sun-spots, in the absenceof any considerable accumulation of observations to sustain them, but the few examples which we have noted are in accordance with these views, and when attention is once called to the basic principles on which they depend, observations will doubtless be made in abundance to prove or disprove what has been here stated. The mere fact of a differential rate of advance among sun-spots, as they pass across the solar face, of itself demonstrates that the active causes of these phenomena must be extra-solar, and if so, their only possible dynamic source must be looked for in the planets, and the remaining conclusions will of necessity follow as a corollary. We may even, by merely examining an accurate drawing of a sun-spot, determine its position and direction upon the solar sphere from which it was delineated by its lines of active eruption and influx of faculæ, and also whether it be a new spot or one which has passed entirely beyond its active stage and is about to finally disappear.As for the faculæ which striate the photosphere, the mottlings and so-called “willow-leaves,” any one who will quietly gaze downward upon the turbid surface of the Mississippi or other similar river, in mid-channel, will see plenty of such faculæ: the river is full of them. The heavier, intermingled clay, slowly subsiding, is caught up in the turmoil beneath the surface and swept upward in elongated ovals and eddies, the larger swells nearly colorless, and others of all shades of ochre and yellow, and the whole as richly mottled, sometimes, as the variegated pattern of a Persian carpet. If we substitutefor the subsiding clay the rapidly sinking heavy metallic vapors, and enlarge the scale from the dimensions of the river to those of the sun, we will have the mottled solar surface with its kaleidoscopic changes, the so-called “willow-leaves,” and the faculæ in all their glory. A careful study of the sun will show most clearly that only in some such explanation as the present view affords can a rational basis for its varied phenomena be found.Illustrating complex lines of planetary electrical energy produced by inclination of sun’s axis.—A B, A′ B′, plane of planetary orbits.Upper figure shows sun’s axis inclined laterally; lower figure, from front to rear, and at right angles to former.C, chromosphere; E E, solar equator; A B, A′ B′, lines of planetary electric currents; F, latitude covered by vertical position of planets, 14° in width; P P, sun’s axis.If the sun’s equator were coincident with the plane of the planetary orbits, it is obvious that all the planetary energies would be directed, whatever the position of the planets around the sun, immediately upon this equatorial great circle, and that, at each revolution upon his axis, corresponding nearly to our calendar month, the same part of his sphere would be exposed to these direct currents, so that the intensity would be, in its aggregate, nearly a constant quantity. But, by reason of the sun’s axial inclination of seven degrees to the plane of the planetary orbits, a far more complex and important condition of affairs ensues. It will be seen at once that the plane of the planetary orbits intersects the sun’s equator at opposite sides, and that, from a minimum of nothing, this line reaches a maximum, twice in each circumference, of seven degrees, one north and the other south of the equator, and that this arc of fourteen degrees, thus traversed by every planet in its orbital rotation around the sun, measures more than one hundred thousand miles from north to south upon the solar surface, nearly one-half the distance which separates theearth from the moon. If all the planets were in conjunction or nearly so, on one side of the sun, for example, and in the vertical plane of the sun’s axis, they would continue to deliver their electrical currents with their greatest intensity upon a single point of his surface fifty-two thousand miles north of his equator, while the opposite point, one hundred and four thousand miles distant, would be unaffected by any direct currents at all. Conversely,if in conjunction on the opposite side of the sun, they would continue to deliver these currents upon a corresponding point fifty-two thousand miles south of the equator; but if in conjunction in the vertical plane transverse to the sun’s axial inclination, these currents on either side of the sun would be delivered directly upon the solar equator. The importance of this will be understood when it is considered that for many of our years such planets as Jupiter and Saturn must continue to direct their currents upon a very slowly changing point of the sun’s surface, by reason of their vast annual rotational period, while with the earth and the interior planets these various points are struck with ever-increasing rapidity as the year decreases in length with the different planets, the earth, Venus, and Mercury. There is a solar equinoctial, so to speak, just as there is a terrestrial equinoctial in which the sun crosses the line twice each year, and the meteorological disturbances faintly shown on the earth at such times are vastly increased on the sun, and rendered far more complex by the interaction of many planets upon the sun, instead of a single sun upon each planet. While our equinoctial has to do with gravity and light and heat, and probably magnetism, the solar equinoctial deals with the vast electrical streams which feed its fires and set it boiling with furious energy, first at one point, then at another, until the increment has been absorbed and adjusted, and thus equalized throughout his mass. What a new interest this must arouse in our study of sun-spots, faculæ, prominences, sun-storms,and the vast panorama of solar action hung up before our astonished eyes! A new world here awaits its Columbus.But not only the planets thus gather, so to speak, electricity for the sun’s support from space; the moon also must do its part, as it rotates in the same manner, subject to the sun, and has its own motion through space. But an examination of the moon shows no atmosphere and no aqueous matter visible to us, and also the singular fact that it constantly presents one side only to the earth. R. Kalley Miller, in his “Romance of Astronomy,” article “The Moon,” says, “After an elaborate analysis, Professor Hausen, of Gotha, found that it could be accounted for only by supposing that the side of the moon nearest us was lighter than the other, and hence that its center of gravity was not at its center of figure, but considerably nearer the side of it which is always turned away from us. He calculates the distance between these centers to be nearly thirty-five miles, evidently a most important eccentricity, when we remember that the radius of the moon is little over a thousand miles. It must have been produced by some great internal convulsion after the moon assumed its solid state; but the forces required to produce this disruption are less than might at first sight appear necessary, owing to the fact that the force of gravitation and the weight of matter are six times less at the moon than with us.” Those who are fond of the so-called “Argument of Design” will be gratified to learn that, if the moon had a rotation upon its ownaxis similar to that of the earth, all life—past, present or future—would have been impossible on that satellite or planet; and that, on the contrary,—provided she always turns the same side of her surface to the earth,—it is quite possible that air, water, and life may exist, or may have existed, on the opposite side of the moon, but not otherwise. In fact, air and water must now exist on the opposite side; and, since her whole supply will thus be condensed upon half her surface or less, even with her small force of gravity, it may be quite sufficient in quantity and density for the support of animal, vegetable, or even human life. By reason of this difference in the lunar center of gravity, the side presented to the earth in physical position is similar to the summit of a mountain upon the earth’s surface two hundred miles high, and surely we would not expect to find much air or water or life at that altitude. But the opposite side would resemble a champagne country at the foot of this enormous mountain, and might be well fitted for human existence. Now, we know that similar electricities repel each other, and air or gases charged with similar electricities are equally self-repellent. Professor Tyndall, in his “Lessons in Electricity,” says, “The electricity escaping from a point or flame into the air renders the air self-repulsive. The consequence is, that when the hand is placed over a point mounted on the prime conductor of a good machine, a cold blast is distinctly felt …. The blast is called the ‘electric wind.’ Wilson moved bodies by its action; Faraday caused it to depressthe surface of a liquid; Hamilton employed the reaction of the electric wind to make pointed wires rotate. The wind was also found to promote evaporation.”Fig. 1, mutual repulsion of similarly electrified pith-balls; 2, the electrical windmill, atmospheric repulsion; 3, repulsion of a flame by electricity; 4, electrical distribution around an oval conductor; 5, mutual attraction of opposite electricities; 5a, mutual repulsion of similar electricities; 6, mutual repulsion of electrospheres of earth and moon; 7, mutual repulsion of electrospheres of sun and comet.While electrical repulsion is doubtless analogous to, and correlative with, the attraction of gravitation, this force, and even gravity itself, has been sometimes interpreted as derived from the mutually interacting molecules of space itself. We may even learn somewhat of how such repulsions of similar and attractions of opposite electrospheres might occur. We constantly speak of positive and negative electricity as though these were different fluids, but such expressions are employed only in the same manner as the analogous terms, heat and cold. We know, of course, that cold is the relative absence of heat, the dividing line being not a fixed, but a constantly changing one, so that one body is cold to another by reason of relative, and not absolute, deprivation of heat. It is well known, however, that cold, which is purely a negative state, manifests the same apparent radiant energy as heat. A vessel near an iceberg is exposed to a wave of cold, precisely as of heat from a heated body at the same distance. This, of course, is due to abstraction and not to increment. All space being occupied by attenuated matter in a state of unstable electrical equilibrium, as we say, which simply means a condition ready to be raised or lowered in tension by absorption from or into outside media, all concrete bodies floating in that space must have an electrical potentialeither equal to, or higher, or else lower than that of their surrounding space. A solitary body in space, if we can conceive of such, in either a higher or lower state of electrical tension, would be drawn upon from all sides to equalize the distribution and restore the general average. But if two bodies occupy the same field, and are widely different from each other in electrical potential, one higher and the other lower than that of space, this distribution will be towards each other, and must be manifested by mutual attraction. But if, on the contrary, these two bodies are both equally higher or lower than the spatial average, they have nothing to give to each other, but have this difference to give to or receive only from outer space, and hence they will be drawn apart or, as we say, mutually repelled. The case is similar to what we see in the case of bodies of water at various levels. Suppose there be a lake of a fixed level, and communicating with it and with each other, by open channels, two ponds of water occupying an island in the middle of the lake. If one of these ponds be higher in level and the other lower than the lake, their waters will rapidly converge, the higher flowing into the lower; but if both are at the same level, and higher than the lake, they will flow apart into the lake. Or, if both are at the same level, and lower than the lake, the water of the latter will equally flow from outside into both ponds, and their waters will still be held separate from each other. The analogies of these various levels may be pursued to any desired extent, as electrical tensionsfind their most exact analogies in the pressures of bodies of water at different levels and of different quantities, and these analogies are those most constantly used in the interpretation of such electrical phenomena.The great electrical activity of the electrospheres of the earth and moon, while they discharge their tremendous currents directly into the sun, at the same time must cause their similarly electrified atmospheres to mutually repel each other, while gravity continues to operate to maintain the earth and moon at their fixed distances from each other, and to retain their gaseous envelopes around their own bodies. The result must be that these similarly electrified atmospheres repel each other with a force proportioned to their masses of atmosphere and the intensity of the electricities of each. The moon’s axial rotation being completed but once in twenty-eight days, and that of the earth once in each day, and the moon’s mass and volume being so much less than those of the earth, whatever of electrified air or moisture she may have (and she must have both, proportionate to her attributes) would have been driven as by a cyclone to the opposite side of the moon and there retained. Now, with an atmosphere and water only on one side of the moon, and that the side opposite the earth, it is obvious that a rotation on her axis at all resembling that of the earth would carry every part of her surface, at each complete rotation, from a region of air and moisture into one deprived of both, and in such a condition she would of necessitybe deprived of both life and its possibility; hence, as the laws of nature compel the lunar atmosphere and moisture to reside permanently on the side always opposite the earth, a co-ordinate arrest of the moon’s axial motion with reference to the earth could alone compensate for such a state of things, and, curiously enough, we find as a solitary exception, compared with the planets, that such is the case. The moon unquestionably has both atmosphere and water on its opposite side. In his recent work, “In the High Heavens,” Professor Ball reviews the physical conditions of the other planets as possible abodes of life. He pronounces against the moon because night and day would each be a fortnight in length; but this is surely no objection, for even in Norway and Greenland such nights and days are not uncommon at different seasons, and thousands of human beings, even as at present constituted on earth, spend their lives there in content and happiness. That the moon also would be terribly scorched by the long day and frozen by the long night does not necessarily follow, for the atmosphere of Mars, that author says, “to a large extent mitigates the fierceness with which the sun’s rays would beat down on the globe if it were devoid of such protection.” As the moon’s opposite face must have a double quota both of atmosphere and clouds, the difficulty will be correspondingly less than on Mars; and as for the “lightness” of bodies on the moon, they would probably get along quite as well as mosquitoes and like “birds of prey” in the marshes along our coasts. The author refersconstantly toourbodies; for example, “Couldwelive on a planet like Neptune?” No, we could not; we would be dead before we got there. Nor couldwelive in the bark of a tree, or at the bottom of the ocean, or in a globule of serum; but living beings are found there nevertheless. The principle is that wherever life is possible there we may expect to find life; and surely life is, or has been, or will be possible, not only on the moon, so far as our knowledge of physical conditions can go, but also on some of the other planets. Of course each planet has its life stage, but this applies not only to the earth, but to all the other planets as well, and not only to the planets of our own system, but to those of all other solar systems. Each has had, or will have, its stage in which life is possible, and these planets may be like human habitations, in which whole races at times migrate from one home to another. There is no conceivable reason why this may not be the general law of creation, and every analogy leads us to believe that it is so.It has been recently announced that, from telescopic observations, the atmosphere of Mars must be at least as attenuated as that among the highest mountainous regions of the earth, if this planet has any atmosphere at all. That it must be far less dense than that of the earth at sea-level is obvious, for the mass and volume of Mars are very much less than those of our own planet; but that Mars is devoid of a gaseous envelope or atmosphere is contrary to what we know of all sidereal physics. The sun, the fixed stars, the comets, the nebulæ, andeven the meteorolithic fragments which fall upon the earth, all show the same elementary chemical constitution as the earth itself, and we cannot believe that Mars alone is differently constituted from every other body we have been able to examine. We have direct evidence, on this planet, of polar snows and their melting away under the sun’s heat; we see the apparent areas of sea and land; it has its moons as the earth has hers, and exhibits all the characteristic phenomena of the earth and other planets. All sidereal bodies that we know of, except, perhaps, our moon, which exception we have fully accounted for, are found to be surrounded by gaseous envelopes or atmospheres of some sort. The sun, the fixed stars, the nuclei of comets, the condensing nebulæ, the planets Jupiter and the earth, which are those under our most direct observation, and even the meteorites, when examined, reveal the presence of many times their own volumes of independent atmospheric gases; and whatever may be the theory of the origin or development of Mars, it must have been subjected to the same influences, the same environment, and the same processes of creation as those of our solar system generally; and that this body alone should possess no gaseous envelope—for the denial of atmosphere denies, at the same time, the presence of any or all surrounding gases—is quite incredible. Only the most positive, direct, and long-continued proofs of such fact could be accepted, and even then the history of all scientific progress shows that what are believed to be facts themselves fluctuate like fancies till, bytheir accumulated force, they solidify into universally accepted demonstration. The fact, moreover, that the atmospheres of the smaller planets are more attenuated than our own and those of the larger ones denser has no bearing, in itself, on the probability of the existence of life on these other planets, for in our own atmosphere oxygen, which is the efficient element, is diluted with four times its quantity of inert nitrogen. These proportions doubtless vary largely in other atmospheres, so that the oxygen may be much richer in some and far poorer, relatively, in others. The mere fact that the presence of nitrogen, probably, and aqueous vapor, certainly, depends on the gravity of the mass of each planet, while the oxygen is due to electrolytic decomposition induced by the combined volume, mass, and rotation, and other causes,—such as the axial inclination of such planets, for example,—renders these variations in the constitution of planetary atmospheres a certainty. As Mars has a diameter much more than one-half that of the earth, and a diurnal rotational period nearly the same, while his mass, which controls the action of gravity, is only about one-ninth that of the earth (see Appleton’s Cyclopædia), it is obvious that his oxygen-gathering power, compared with that for accumulating nitrogen and aqueous vapor, is much higher than that of the earth, and we should expect to find there an attenuated atmosphere very rich in oxygen, and with a relatively smaller proportion of aqueous vapor, or even water, on his surface. Such seem to be the facts as far as observed.In operating an electric machine the strength of the current is directly proportionate to the speed of rotation,—that is to say, to the velocity of the generating surface; for example, of the Wimshurst induction machine it is stated (page 63, “Electricity in the Service of Man”), “These four-and-one-half inch discharges take placein regular succession at every two and a half turnsof the handle.” It is also a well-established law of electrolysis that “The amount of decomposition effected by the current is in proportion to the current strength.” Professor Ferguson (“Electricity,” page 225) says of the voltameter, an instrument devised by Faraday, and used for testing the strength of currents by the proportionate decomposition of acidulated water, “Mixed gases rise into the tube, andthe quantity of gas given off in a given time measures the strength of the current.” Roughly estimating the diameter of Mars at five-eighths, the surface velocity at three-fifths, and the mass at one-ninth those of the earth, this planet should have an atmosphere containing about sixty per cent. of oxygen and forty of nitrogen, with a barometric pressure at sea-level of about six and one-half inches of mercury. This would be an excellent atmosphere,—about equal in its quota of oxygen for each respiration to that of the higher areas of Persia, a great country for roses. The aqueous vapors lying low and near the surface would serve as a vaporous screen to concentrate and retain the sun’s heat and retard radiation from that planet. Nothing in particular seems to be the matter with Mars.On the contrary, the mass of Jupiter is so great, and his attraction of gravity so powerful, that it is only by his exceedingly rapid diurnal rotation (once in less than ten hours) that it is possible for him to accumulate any effective percentage of oxygen at all. But there is certainly plenty of water there.We may approximately compute, in general terms, the proportion of oxygen in the atmospheres of the other planets in the same way. Neptune, it is true, is so far distant from the sun that the solar orb only “appears about the same magnitude as Venus when at its greatest brilliancy, as viewed from the earth,” but we must not forget that “theintensityof the sun’s light would be more than ten thousand times greater than that of Venus” (Professor Dunkin, in “The Midnight Sky”). Unless the moon gathers a portion of the earth’s oxygen (the planetary satellites, like Saturn’s rings, thus constituting in their rotations a constituent part of the planets themselves), the percentage of this gas in her atmosphere must be exceedingly small, for her axial rotation has a period of a whole lunar month, being the same as that of her revolution around the earth as a center.The absence of apparent atmosphere and moisture from thevisiblelunar surface has already been mentioned and explained. The means by which this fact has been approximately determined are described by Professor Dunkin, in “The Midnight Sky,” as follows: “Among the many proofs of the non-existence of a lunar atmosphere, it maybe mentioned that no water can be seen; at least there is not a sufficient quantity in any one spot so as to be visible from the earth. Again, there are no clouds; for if there were, we should immediately discover them by the variable light and shade which they would produce. But one great proof of the absence of any large amount of vapor being suspended over the lunar surface is the sudden extinction of a star when occulted by the moon. The author has been a constant observer of these phenomena, and, though his experience is of long standing, he has never observed an occultation of a star or planet,especially at the unilluminated edge of a young moon, without having his conviction confirmed that there is no appreciable lunar atmosphere …. Professor Challis has subjected the results of a large number of these observations to a severe mathematical test, but he has not been able to discover the slightest trace of any effect produced by a lunar atmosphere.”In Appleton’s Cyclopædia, article “The Moon,” it is stated that “Schröter (about 1800) claimed to have discovered indications of vegetation on the surface of the moon. These consist of certain traces of a greenish tint which appear and reappear periodically; much as the white spots covering the polar regions of Mars …. As we are able, under the most favorable conditions, to use upon the moon telescopic powers which have the effect of bringing the satellite to within one hundred and fifty to one hundred and twenty miles of us, we should doubtless notice any such markedchanges on her surface as the passage of the seasons produces, for example, on our own globe.” Very recently (August 12, 1894), it has been stated, Professor Gathmann has observed a peculiar green spot about forty by seventy miles in area near the crater of Tycho Brahe, “on thenorthwestern edgeof the satellite’s upper limb,” which had disappeared twenty-two hours afterwards.We understand, of course, that the moon’s librations, by the variation of position of the lunar body, enable us to see, at times, around the edge of this satellite somewhat, so that, instead of observing only one-half, we can in this way see nearly six-tenths of her surface, but not at the same time, of course. When the moon is dark it occupies a position between the earth and the sun, and only its opposite face is illuminated. In this position the attraction of solar gravity and the attraction of the electrically opposite solar electrosphere both accumulate their forces upon the moon’s atmosphere in the same line as the repulsion of the earth’s similar electricity, so that the lunar moisture and atmosphere are, at this part of her subordinate orbit, most powerfully forced away from the direction of the earth. As the moon now proceeds towards her first quarter, the terrestrial repulsion drives her atmosphere radially outward, while solar gravity and electrical attraction tend to hold it in the direction of the sun. The result will be an electrospheric libration, so to speak, and the moon’s atmosphere and moisture will be carried around towards its illuminated face and, to someextent, will overlap the area of terrestrial repulsion. But as the moon advances this will gradually diminish, soon cease, and finally be reversed as it again approaches darkness. We can now understand why the green surface, if it really was due to vegetation, appeared along thelunar marginat the time described above, and also that the observation of planetary occultations “at the unilluminated edge of the young moon” was the very worst part of the moon and its orbit in which to look for air or moisture; as the sun’s influence is then directlyaway fromthe unilluminated surface of the moon, and his “pull” would have, in fact, still further denuded the very portion most persistently examined, and where this absence of atmosphere wasespeciallynoted.When considering the transference of energy from the peripheral regions of the solar system to the center, its conversion there into a new form of molecular force, and its subsequent distribution, we find a curious and instructive parallel in the action of the reflex nervous system of animal life. This system is one in which the brain or other conscious center of nerve-energy takes no part. Tickle the foot of a child, for example, and its whole muscular system is thrown into uncontrollable convulsions of laughter. Here an exciting contact with the terminal filaments of the afferent or sensory nerves is rapidly carried into the local nerve-center of this part of the system,—that is, the sensory column of the spinal cord. This center of ganglionic nerve-matter lies directly against the correspondingmotor mass, both freely communicating with each other. The sensory current passing into its central ganglion undergoes some peculiar change of character, probably one of intensification, such as is observed in the action of the condenser of an electrical machine, through which sensory ganglion, thus raised in potential, it passes to the motor ganglion adjacent, where it is instantly transformed into an entirely different form of energy. The sensory character has now entirely disappeared, and it has been converted into and is flashed forth as motor energy to the different muscles of the body, which are immediately contracted, the violent molecular motion of the fibres being at once converted into muscular motion in mass. The changes are entirely analogous to those we see in the different conversions of energy in our solar system. Considering the surface of the body as a planetary electrosphere, it is acted upon by excitation from without; currents of energy are engendered, which are at once transmitted to the sensory ganglion, corresponding to the hydrogen atmosphere or electrosphere of the sun; intensification of action here ensues, the current passing through this ganglion or atmosphere into the solar body itself, which corresponds to the motor ganglion; both ganglia are now highly excited; the electrical force is converted into the radiant molecular motor energy of heat and light in the sun and muscular excitement in the body, and these are flashed forth and find scope for their action within the body of the subject or upon the surface of the planets, whichlie, like the muscular structure of the body, within the genetic electrosphere where, acted upon from without and by agencies entirely external, moving contact has induced the primary molecular action, which was then instantaneously transferred to the center, there converted into another form, that of motor energy, and thence sent forth to produce action in the muscles of the body in the one case, and in the other upon the planetary bodies and their satellites and other structures which occupy surrounding space.

The remarkable resemblance between the mode of operation and effects of these electrical induction machines and the vast rotating electrosphere of the earth must be at once apparent. The operation is precisely the same, and the results must,pari passu, be substantially similar. We need not seek for precise parallelism of structure, because these machines themselves, it has been shown, widely differ in structure among themselves. But the almost infinitely more vast terrestrial electrosphere, which cannot be less than ten thousand miles in diameter, and perhaps much more (if we may form an opinion from the relative magnitude of the field of action of the hydrogen envelope which constitutes the solar electrosphere), rotating in the attenuated vapors of space, among which vapors that of water plays a most important part, and which vapors constantly impinge with various disturbances of contact against the more and more attenuated layers of the terrestrial atmosphere, and which gradually, from within outward, less and less partakes of the earth’s rotation until, finally, its rotatory movement is lost in the vast ocean of space, establishes the certainty that enormous quantities of electricity must there be disengaged, preciselyas in the machines which we have described, and to learn the potential or active pressure of this electricity we have only to consider the fact that we find a rise so rapid, as we ascend through our atmosphere, that the potential increases by from twenty to forty volts for each foot. That these currents are transmitted to the sun without appreciable resistance we already know, and that they are there transformed into light and heat we can, from the previously cited experiments, see.

But it may be urged that the resistance of such attenuated vapors in space, and the generation of electricity in such quantities, would inevitably retard and finally destroy planetary motion. The sufficient answer to this is found in the consideration that the same facts must exist under any possible mode of organization of our solar system, and that such interference, besides, must have absolutely prevented its formation at all, if such were the case. All the matter of our planetary system together is only one seven-hundred-and-fiftieth that of the sun; if this were added to the sun’s bulk it would but slightly enlarge it. But all this solar and planetary matter together, if distributed over the space occupied by our planetary system,—and, by the nebular hypothesis of the organization of our solar system, this is requisite,—and having an axial diameter one-half that of its equatorial (see Proctor’s “Familiar Essays on Scientific Subjects,”—“Oxygen in the Sun”), would have had a density of only about one four-hundred-thousandth that of hydrogen gas at atmospheric pressure. This nebular mass musthave had a diameter at least sixty times that of the distance of the earth from the sun and a depth of thirty times its distance. That this enormous mass of attenuated matter should ever have been made to rotate as a whole by any force of attraction, repulsion, or rotation, with a tenuity so great that, if measured by an equal volume of hydrogen gas,—the lightest substance known to us,—it would have furnished material for four hundred thousand such systems as ours, presupposes a resistance so slight that the planets themselves, when coagulated out of such a mass, could never in any conceivable time exhibit retardation from such a source; and we know to a certainty that such attenuated vapors do exist in space, for electricity cannot be transmitted through a vacuum, and it is transmitted with perfect freedom between the earth and the sun. But it may be said that the laws were then different. If they were different then, they are doubtless different now. If, on the other hand, we assume that the bodies of which our solar system is composed were simply aggregated into concrete masses from meteoric dust, the difficulty is not lessened; for if the resistances to their operation now are such as to perceptibly retard their motions, they must have operated still more powerfully to originally prevent them; while, if hurled forth by an almighty fiat, complete from the hand of creative energy, the same force which impelled them forward must have also established the laws under which they now move.

It is calculated that our earth must be losingtime, by tidal retardation, at the rate of one-half the moon’s diameter in each twelve hundred years (see Proctor, “Light Science for Leisure Hours,”—“Our Chief Timepiece Losing Time”), and that “the length of a day is now more by about one eighty-fourth part of a second than it was two thousand years ago.” Perhaps, however, we may discover that these changes are themselves periodic and increase in cycles to a maximum, and then diminish, as is the case with magnetic, planetary, and stellar variations, and other similar changes, when sufficiently long observed; for while such changes may very well accompany a theory under which our system and all other systems are slowly running down to decay and death, it is entirely incompatible with the primal forces under which theymusthave been originally formed. In other words, if the tides are dragging back our earth without compensation, this dragging back can only come from the oceanic deposit of water on the earth from the aqueous vapors of space which do not partake of the planetary rotation and orbital movement of the earth. But if these can now retard the earth’s motion, they must have originally prevented it in the beginning. This loss of time is, moreover, merely inferential from mathematical computations, and its basis is found in the belief that all the operations of nature are in a slow process of degradation, and the calculated loss itself may be merely theoretical, and not true in fact. Professor Proctor himself concedes the uncertainty of this alleged retardation when he says in the samearticle, “At this rate of change our day would merge into a lunar month in the course of thirty-six thousand millions of years. But after a while the change will take place more slowly, andsome trillion or so of yearswill elapse before the full change is effected.”

While the processes of nature are generally believed to be running down, everything is bent to that belief; but the forces of nature must, nevertheless, be uniform and supreme, for it is by these forces that the expected results are to be achieved. That changes occur constantly is inevitable, but the source of these must be looked for in the interaction of original forces, and not in the degradation of systems. There is reason to believe, in fact, that the repulsion of the terrestrial electrosphere by that of the moon may itself be sufficient to counteract such retarding force of lunar gravity, for the tides upon earth are not merely oceanic, but atmospheric, and on the latter the electrical repulsion of the moon must act very powerfully and with directly counteractive effect.

Planetary generation and transmission of electrical energy.—A, the planet; B, electrosphere showing circles of gradually diminishing rotation; E, interplanetary space; D, curve of gradually diminishing rotation; F, F, currents of electricity flowing to the sun; S, direction of the sun.

Planetary generation and transmission of electrical energy.—A, the planet; B, electrosphere showing circles of gradually diminishing rotation; E, interplanetary space; D, curve of gradually diminishing rotation; F, F, currents of electricity flowing to the sun; S, direction of the sun.

Let us now apply the preceding principles to the problem under review. All planetary space is pervaded with attenuated vapors or gases, among which aqueous vapor occupies a leading place. The planets and all planetary bodies, having opposite electrical polarity from the central and relatively fixed sun, by their orbital motions around and constant subjection thereto act as enormous induction machines, which generate electricity from the ocean of attenuated aqueous vapor, each planet being surroundedby an enormous electrosphere, carried with the planet in its axial and orbital movements, the successive atmospheric envelopes gradually diminishing in rotational velocity until merged into the outer ocean of space. As the planets advance in their orbits they plunge into new and fresh fields, and, as the whole solar system gradually movesonward through space, these fields are never re-occupied. These electrospheres, by their rotation, generate enormous quantities of electricity at an extremely high potential,—so high that we can scarcely even conceive it,—and this electricity flows in a constant current to the sun, where it disappears as electricity, to reappear in the form of solar light and heat. These planetary currents also flow towards such other negatively electrified bodies as may exist in space—the comets and fixed stars, for example—in proportion to their distance; for, since resistance is not appreciable between ourselves and the sun, as is also the case with light, so, like light, our electricity must pass outward as well as inward to take part in the harmonious operations of the whole universe. But it should be noted that the distribution of electric energy in the form of currents is quite different from that of light or other radiant energy; for while light is diffused from a center outward through space, electric currents, on the contrary, are concentrated and directed along lines of force to concrete centers of opposite polarity. As a consequence, the intensity of light decreases according to the squares of the distances traversed plus the resistance to the passage of the light itself, while the electric current is only diminished by the resistance of the medium through which it passes. As the light of the sun has a velocity of one hundred and eighty-eight thousand miles per second, and the electric current between the earth and the sun the same, it will be seen that the resistance is practically alike for these two formsof energy. Indeed, the striking resemblance between the ethereal vibrations which constitute light and heat and exceedingly rapid alternating currents of electricity through molecular media may suggest that the transformation of one force into the other is some sort of a “step-up” or “step-down” process, much higher in degree, but of the same character as the well-known analogous electrical transformations used in the arts. It should also be borne in mind that, while theintensityof light diminishes according to the above law, thequantityremains the same, less resistance, as the area covered increases precisely in the same proportion as the intensity diminishes,—that is, in the ratio of squares.

Upper figure.—Gradual discharge between two conductors, in partial vacuum.Lower figure.—Sudden electric discharge through the atmosphere, from left to right.

Upper figure.—Gradual discharge between two conductors, in partial vacuum.

Lower figure.—Sudden electric discharge through the atmosphere, from left to right.

Around the earth and other planets gravity attracts the aqueous vapors in increased density, the same as around the sun; but the electric currents passing between the planets and the sun decompose this aqueous vapor into its constituent gases, hydrogen and oxygen. The oxygen is deposited within the positive electrospheres of the planetary bodies, where it mingles with nitrogen to form our atmosphereand those of the other planets. In this float the aqueous vapors condensed from space, which are lighter than air. (See Tyndall, “The Forms of Water:” “It also sends up a quantity of aqueous vapor which, being far lighter than air, helps the latter to rise.”) These aqueous vapors, condensed into clouds and precipitated upon the earth, form our oceans and their affluents. The hydrogen gas disengaged upon the sun’s surface forms a similar envelope, which is penetrated by the planetary electric currents, and is thus highly heated and rendered incandescent; the glowing hydrogen transmits its heat to the sun’s mass within, which is thus raised to, and permanently maintained in, a liquid or densely gaseous state, its metallic constituents being volatilized in part, and these metallic vapors mingle with the lower strata of hydrogen to form the sun’s photosphere, while, above, the glowing hydrogen grows more pure, and finally, at a distance of hundreds of thousands of miles, is merged into the corona, which is composed, in part at least, of cosmical dust rotating around and repelled by the sun, and which shines partly by reflected light, partly by that of the relatively cooler hydrogen, and partly, perhaps, by electrification of its constituents by the powerful currents passing through it. Each of the planetary bodies, large or small, takes its proportionate part in the generation and transmission of electricity, according to its volume, mass, and motion. As an adjunct to this electrical sequence we have learned that any interruption of such currents between the generatorand the receiver will cause the generating apparatus to glow with diffused electrical light, as is the case with the Wimshurst machine already described. When such connection is removed, it is said, “the whole apparatus bristles with electricity, and if viewed in the dark presents a most beautiful appearance, being literally bathed with luminousbrushdischarges.” Such a phenomenon recalls at once the aurora borealis; and when we find this as a sequence of the electrical storm of the first of September, 1859, before described (“at night great auroras were seen in both hemispheres”), and connect with this the persistence of electricity upon insulated surfaces (see “Electricity in the Service of Man,” page 53: “Glass being a bad conductor, the electricity does not spread all over the plate, but remains where it is produced”), we shall inevitably conclude that there was some partial interruption in the current flowing from the earth to the sun at that moment; and if we recall that at that very instant “suddenly a bright light was seen by each observer to break out on the sun’s surface and to travel across a part of the solar disk,” we shall learn that the processes connected with the production of such a bright light will interrupt in part the terrestrial current. We can readily understand that if this bright light exceeded in electrical intensity that due to the earth’s current, it might temporarily reverse the polarity of the afferent current or retard its flow, like the so-called “backwater” of a mill. It would be like attempting to discharge steam at sixty pounds’ pressure into a vessel filled withother steam at sixty-one pounds. Whence, then, came this bright light? Perhaps from the conjoint action of some other planet, perhaps from sudden chemical disassociation beneath the surface, perhaps by the abnormal piling up of depths of transparent glowing hydrogen or other local disturbance.

Position of planets with reference to the generation of sun-spots.—S, the sun; S′, axis of sun’s rotation inclined 7° to plane of planetary rotation; A B, C, D, maximum intensity of planetary action; A′, B′, C′, D′, minimum intensity of same.

Position of planets with reference to the generation of sun-spots.—S, the sun; S′, axis of sun’s rotation inclined 7° to plane of planetary rotation; A B, C, D, maximum intensity of planetary action; A′, B′, C′, D′, minimum intensity of same.

And this leads to the consideration of the uniformity of solar action. The planetary electrospheres will be constant in their operation if the constitution of surrounding space remains uniform; but we shall find reason to believe that there are currents in the ocean of space, as there are currents in our own seas, and electrical generation will necessarily vary when such currents are encountered. The sun itself in such case, however, will become an automatic regulator, for his density being but one-fourth that of the earth, and the spectroscope having shown his chemical composition to a large extent, we know that his mass must be either liquid or vaporous, and perhaps in part both. Such masses readily respond to variations of temperature, expanding as it rises and contracting as it falls. Hence, if a portion of space were reached where the action of the planetary electrospheres was increased by relative increase of temperature in some interstellar “Gulf Stream,” the sun’s volume would expand and compensation be at once established, while, conversely, with diminution of such planetary action, the solar volume would contract and an increased supply from his reserve store be given out thereby. In this way the condensation relied upon to give us heat forseven or seventeen million years becomes a compensating mechanism, self-operative through the most distant cycles of time. We shall also find in such electric currents an explanation of sun-spots. It is not meant that a full knowledge can be obtained of their minute constitution, nor is it necessary; but the equatorial belt of six degrees, nearly free from sun-spots, we can readily understand to be caused—since sun-spots are depressions in the photosphere down to the deeper and denser cloud strata beneath—by the equatorial piling up of the sun’s atmosphere by its rotation. Any point on the sun’s equator travels at four times the rotational velocity of one on the earth’s equator, but the sun’s attraction of gravity is twenty-seven and one-tenth times that of the earth, so that the piling up of an atmosphere of hydrogen would be considerable, and such depressions would not ordinarily exist there. Similarly, near the sun’s poles we should find a gradual darkening, as is the case; but from five degrees to thirty degrees latitude, the sun, in its rotation, by reason of the inclination of its axis, passes at every point directly beneath the planets, or within their area of control, and here we find the solar spots in their greatest number, size, and intensity. These sun-spots cross the face of the sun in about fifteen days, and vary in development from year to year, having a cycle of 11.11 years from maximum to maximum. They also have a long cycle of about fifty-six years. (See article “The Sun,” in Appleton’s Cyclopædia.) “Wolf, in 1859, presented a formula by which the frequency of spotsis connected with the motions of the four bodies, Venus, the earth, Jupiter, and Saturn. Professor Loomis, of Yale College, has since advocated a theory (suggested by the present writer [Proctor] in 1865, in ‘Saturn and his System,’ page 168, note) that the long cycle of fifty-six years is related to the successive conjunctions of Saturn and Jupiter. But the association is as yet very far from being demonstrated, to say the least.” Should such fact be established, an explanation for it will be found in the direct impact of the condensed electric currents from several planets approaching conjunction, and raising a portion of the sun’s atmosphere suddenlyto a higher temperature and volatilizing an abnormal proportion of the semi-vaporous metallic core beneath. This would form an upburst piling the intensely heated faculæ up on the sides and revealing the relatively darker masses of cloud beneath, the cooler supernatant hydrogen pouring in from the upper layers to fill the returning void. This is precisely what is seen in such spots and their surrounding disturbances. In the article “The Sun,” above quoted, we read, “Mr. Huggins has found that several of the absorption bands belonging to the solar spectrum are wider in the spectrum of a spot, a circumstance indicative of increased absorption so far as the vapors corresponding to such lines are concerned …. Near the great spots or groups of spots there are often seen streaks more luminous than the neighboring surface, calledfaculæ. They are oftenest seen towards the borders of the disk.” This writer also describes “luminous bridges across spots which sink into the vortex and are replaced by others of the numberless cloud-like forms from one hundred to one thousand miles in diameter, the brilliancy of which so greatly exceeds that of the intervening spaces that they must be recognized as the principal radiators of the solar light and heat.” The apparent retardation of the spots most distant from the sun’s equator may also be partially, at least, explained by planetary currents of electricity, as the equatorial atmosphere is deeper and more likely to carry forward such vortices when formed, while the planets act more directly on the sun’s mass beneath their direct influence.

Let us consider this retardation of sun-spots somewhat more in detail. Take, for example, the case of a large planet at such orbital position that its direct line of electrical impact will penetrate the photosphere at (say) seven degrees north solar latitude, which is about fifty-two thousand miles from his equator. During its annual revolution this planet will traverse, with its line of energy, every point of the sun’s surface down to seven degrees south latitude and back again to its initial point, thus tracing a close spiral around the sun for fourteen degrees, or about one hundred and four thousand miles in width. The centrifugal force of the solar rotation piles up the photosphere and the chromosphere around the sun’s equator, precisely as our atmosphere is piled up around our own equator. If the planet be a large one (for distance has but little to do with these electrical currents at planetary distances, in which they differ entirely from light, heat, and gravity), or if there be two planets nearly in conjunction, the body of the chromosphere and the surface of the photosphere will gradually become highly heated, for currents of electricity, of themselves, do not directly heat the solar core any more than a like current heats the under carbon of an arc lamp, the high temperature in both cases being altogether due to the incandescent heat of the interposed arc or envelope. Faculæ of intense brightness will then appear upon the photosphere, and these will be driven forward and also outward in the direction of the higher latitudes, producing an oblique forward movement from difference ofrotational speed at different portions of the sun’s surface. Similar phenomena are constantly observed on the surface of the earth in the generation and behavior of cyclones and other atmospheric disturbances. They may be compared to the wake of a vessel anchored in a strong tide-way. These faculæ will slowly raise the temperature of the surface of the sun’s core beneath to the point of eruptive volatilization, and particularly so if the planet is receding from, instead of advancing towards, the solar equator. At some point in advance of the line of planetary energy an eruption of volatilized metals will suddenly occur, first thrusting up a vast area of the photosphere and then bursting it asunder, which will drive these ruptured masses with enormous speed forward and obliquely outward from the equator. Such faculæ (see Proctor’s “Light Science”) sometimes reach a velocity of seven thousand miles per minute, while the sun’s rotational movement at the equator is less than seventy miles per minute. This sudden eruption will be almost immediately succeeded by great expansion and consequent fall of temperature, so that within a few hours the heavy volatile metals begin to condense and rapidly recede into their crater, and the faculæ in front and at the sides will now stream inward to occupy this vacuum with constantly accelerated velocity, pouring over the edges like the rush of waters at the Falls of Niagara. As they sweep downward over the inner rim of the funnel, these streams of faculæ will glow with increased whiteness, and appear tobe sharply cut off at their inner ends; but this is only apparently so, and is due to the position of the observer, who looks almost directly downward upon these descending streams. It is for the same reason that the faculæ appear more brilliant when near the borders of the solar disk (see page 109). Any good view of a sun-spot when analyzed will show the streams of faculæ thus pouring inward, and they are among the most peculiar and conspicuous phenomena to be observed. The drawings of Professor Langley, reproduced in thePopular Science Monthlyfor September, 1874, and July, 1885, are particularly striking in their illustration of these effects, though their significance and interpretation were not then at hand.

Analysis of a typical sun-spot. Intersections of lines drawn between AA and MM, CC and MM, show state of active eruption; DD, inflowing faculæ pouring downward over the rim; PP, the same; OO and BB a floating bridge, partially completed, supported by the uprush, and along the line NN torn asunder, and upward into plumes and sprays. The general surface shows the mottlings and faculæ. The partial formation of a loop is shown at XX, YY. The line EQ represents the sun’s equator; fromreartofront, the direction of solar rotation. The line of planetary impact is in rear.

Analysis of a typical sun-spot. Intersections of lines drawn between AA and MM, CC and MM, show state of active eruption; DD, inflowing faculæ pouring downward over the rim; PP, the same; OO and BB a floating bridge, partially completed, supported by the uprush, and along the line NN torn asunder, and upward into plumes and sprays. The general surface shows the mottlings and faculæ. The partial formation of a loop is shown at XX, YY. The line EQ represents the sun’s equator; fromreartofront, the direction of solar rotation. The line of planetary impact is in rear.

But while these heavy metallic vapors so rapidly condense and subside in the forward or initial portion of the sun-spot under observation, new depths of intensely-heated faculæ are generated behind, and these operate with renewed energy upon the fresh surface of the solar core in rear of the original seat of eruption; so that each sun-spot, while in an active state, will exhibit two entirely distinct aspects, the forward portion of the crater in a state of rapid condensation and subsidence of the recently erupted metallic vapors, and with inflowing streams of incandescent hydrogen from the front and sides, and the rear portion of the crater up to its rearward wall, and even streaming forth from beneath it, in a state of violent eruption. The large volcanic craters of the Hawaiian Islands exhibit similar partial eruptions and subsidences progressingsimultaneously in the same depths. The sudden formation of the great incandescent loops and plumes to which Professor Langley calls especial attention, and which have hitherto been so perplexing, can now be readily understood and explained. If one of these inflowing streams be carried partially down into and across the crater, and then caught, in its advance, by the uprush in the central or rear portions of the cavity, it will be at once swept upward alongside the ascending eruption,and either scattered at its forward extremity into sprays and plumes, or else thrown forward bodily in the form of a more or less complete loop. In a sun-spot fifty thousand miles in diameter, such a loop, having a long diameter of twenty thousand miles, if we give a speed to the faculæ of seven thousand miles per minute, would be formed in about seven minutes, during which the sun-spot would itself have advanced less than five hundred miles across the face of the sun. The luminous bridges which form so suddenly across portions of the crater may be explained in a similar manner: they are streams of faculæ floated on the nearly balanced uprush of metallic vapors from beneath.

Retardation of sun-spots by continuous development to the rear, and recession in front, as the sun rotates on its axis. The short arrows represent lines of planetary energy; the long arrows show the direction of the sun’s rotation.The dark inner disk represents the solar core, the white circle the photosphere, the mottled area the chromosphere and faculæ, and the dark outer ring the corona. Loops and tufted sprays are shown, caused by inflowing faculæ in front, caught by the uprush of active portions of the sun-spot towards rear.

Retardation of sun-spots by continuous development to the rear, and recession in front, as the sun rotates on its axis. The short arrows represent lines of planetary energy; the long arrows show the direction of the sun’s rotation.

The dark inner disk represents the solar core, the white circle the photosphere, the mottled area the chromosphere and faculæ, and the dark outer ring the corona. Loops and tufted sprays are shown, caused by inflowing faculæ in front, caught by the uprush of active portions of the sun-spot towards rear.

It will thus be seen that a sun-spot is not merely a fixed eruption, like a volcano, but rather a continuous series of eruptions, like a line of activity following, for example, the great terrestrial volcanic curve which extends up the western coast of America, across the Pacific Ocean and Asia, and into Central and Southern Europe, for during its progression its scene of action is constantly being shifted to the rear; it is like a furrow cut by a plough, in which the upturned sod is constantly falling in at one end of the furrow while the plough is cutting a new furrow at the other, except that in this case the plough is relatively fixed overhead, and the field itself passes along beneath it. Consequently, the center of activity of a sun-spot is only in its rear portions, generally considered, and the whole sun-spot is gradually retreating, by successive filling up in front and opening out behind, fartherand farther to the rear,—that is to say, to the east,—so that retardation relatively to the rotational advance of the photosphere necessarily ensues.

But when the sun-spot is developed upon or near the equatorial line this retardation is not so considerable, for the deeper layers of the photosphere in those regions are slower to act and require greater energy to affect them, so that all except deep and violent eruptions fail to show themselves at the surface at all, and the heated faculæ are carried directly forward along the surface of the equatorial swell, so that the center of activity is driven forward more rapidly than in the higher latitudes, and the rate of progression is more nearly coincident with that of the photosphere. But if these facts are correctly stated and explained, we may have to revise our calculations of the sun’s rotational period, for retardation to some extent must occur in all cases, if in any.

A sun-spot, we thus perceive, is an elongated wave or ridge of eruption along the rotational direction of the sun’s body. Why, then, it may be asked, is not this line of eruption continuous entirely around the sun? For the same reason, it may be answered, that our own cyclones are not continuous, though caused substantially in the same manner, and that volcanic eruptions only occur at long intervals, though the forces at work are continuous. Lowering of temperature follows swiftly after eruption, and as the deeper structures of the solar nucleus become gradually affected, instead of volatilization of the outer layers of the surface, we will have diffused gaseous expansion of large portions,and finally of the entire solar mass, which cannot as a whole be volatilized by any conceivable planetary energy. We see these operations exemplified in heating a bar of copper in a Bunsen flame; the latter first turns green from surface volatilization of the copper, but as the heat is communicated to the deeper structures the green flame disappears, and the whole additional heat goes to raise the temperature of the mass.

These processes in the sun are thus seen to be self-compensatory in their nature. They are the means provided to distribute the restricted areas of abnormally heated photosphere over the solar surface, and finally to cause the absorption of the whole excess of heat in the sun’s central mass. The balance is so evenly maintained, however, that, were all the planets equally distributed with reference to the sun’s surface, such sun-spots would be the exception and not the rule, and their distribution would be equal and constant; but, as the planets continually change their positions with reference to the sun and to each other, only by some such provision of nature could the internal structure of the sun be maintained without serious derangement, or, indeed, final disruption. So nature distributes her stores of heat upon the earth. These beautiful self-compensations we shall find suddenly appearing, as we advance, in all parts of the field of astronomical research.

It may seem like temerity to advance statements so positive and specific as to the cause, constitution, and progression of sun-spots, in the absenceof any considerable accumulation of observations to sustain them, but the few examples which we have noted are in accordance with these views, and when attention is once called to the basic principles on which they depend, observations will doubtless be made in abundance to prove or disprove what has been here stated. The mere fact of a differential rate of advance among sun-spots, as they pass across the solar face, of itself demonstrates that the active causes of these phenomena must be extra-solar, and if so, their only possible dynamic source must be looked for in the planets, and the remaining conclusions will of necessity follow as a corollary. We may even, by merely examining an accurate drawing of a sun-spot, determine its position and direction upon the solar sphere from which it was delineated by its lines of active eruption and influx of faculæ, and also whether it be a new spot or one which has passed entirely beyond its active stage and is about to finally disappear.

As for the faculæ which striate the photosphere, the mottlings and so-called “willow-leaves,” any one who will quietly gaze downward upon the turbid surface of the Mississippi or other similar river, in mid-channel, will see plenty of such faculæ: the river is full of them. The heavier, intermingled clay, slowly subsiding, is caught up in the turmoil beneath the surface and swept upward in elongated ovals and eddies, the larger swells nearly colorless, and others of all shades of ochre and yellow, and the whole as richly mottled, sometimes, as the variegated pattern of a Persian carpet. If we substitutefor the subsiding clay the rapidly sinking heavy metallic vapors, and enlarge the scale from the dimensions of the river to those of the sun, we will have the mottled solar surface with its kaleidoscopic changes, the so-called “willow-leaves,” and the faculæ in all their glory. A careful study of the sun will show most clearly that only in some such explanation as the present view affords can a rational basis for its varied phenomena be found.

Illustrating complex lines of planetary electrical energy produced by inclination of sun’s axis.—A B, A′ B′, plane of planetary orbits.Upper figure shows sun’s axis inclined laterally; lower figure, from front to rear, and at right angles to former.C, chromosphere; E E, solar equator; A B, A′ B′, lines of planetary electric currents; F, latitude covered by vertical position of planets, 14° in width; P P, sun’s axis.

Illustrating complex lines of planetary electrical energy produced by inclination of sun’s axis.—A B, A′ B′, plane of planetary orbits.

Upper figure shows sun’s axis inclined laterally; lower figure, from front to rear, and at right angles to former.

C, chromosphere; E E, solar equator; A B, A′ B′, lines of planetary electric currents; F, latitude covered by vertical position of planets, 14° in width; P P, sun’s axis.

If the sun’s equator were coincident with the plane of the planetary orbits, it is obvious that all the planetary energies would be directed, whatever the position of the planets around the sun, immediately upon this equatorial great circle, and that, at each revolution upon his axis, corresponding nearly to our calendar month, the same part of his sphere would be exposed to these direct currents, so that the intensity would be, in its aggregate, nearly a constant quantity. But, by reason of the sun’s axial inclination of seven degrees to the plane of the planetary orbits, a far more complex and important condition of affairs ensues. It will be seen at once that the plane of the planetary orbits intersects the sun’s equator at opposite sides, and that, from a minimum of nothing, this line reaches a maximum, twice in each circumference, of seven degrees, one north and the other south of the equator, and that this arc of fourteen degrees, thus traversed by every planet in its orbital rotation around the sun, measures more than one hundred thousand miles from north to south upon the solar surface, nearly one-half the distance which separates theearth from the moon. If all the planets were in conjunction or nearly so, on one side of the sun, for example, and in the vertical plane of the sun’s axis, they would continue to deliver their electrical currents with their greatest intensity upon a single point of his surface fifty-two thousand miles north of his equator, while the opposite point, one hundred and four thousand miles distant, would be unaffected by any direct currents at all. Conversely,if in conjunction on the opposite side of the sun, they would continue to deliver these currents upon a corresponding point fifty-two thousand miles south of the equator; but if in conjunction in the vertical plane transverse to the sun’s axial inclination, these currents on either side of the sun would be delivered directly upon the solar equator. The importance of this will be understood when it is considered that for many of our years such planets as Jupiter and Saturn must continue to direct their currents upon a very slowly changing point of the sun’s surface, by reason of their vast annual rotational period, while with the earth and the interior planets these various points are struck with ever-increasing rapidity as the year decreases in length with the different planets, the earth, Venus, and Mercury. There is a solar equinoctial, so to speak, just as there is a terrestrial equinoctial in which the sun crosses the line twice each year, and the meteorological disturbances faintly shown on the earth at such times are vastly increased on the sun, and rendered far more complex by the interaction of many planets upon the sun, instead of a single sun upon each planet. While our equinoctial has to do with gravity and light and heat, and probably magnetism, the solar equinoctial deals with the vast electrical streams which feed its fires and set it boiling with furious energy, first at one point, then at another, until the increment has been absorbed and adjusted, and thus equalized throughout his mass. What a new interest this must arouse in our study of sun-spots, faculæ, prominences, sun-storms,and the vast panorama of solar action hung up before our astonished eyes! A new world here awaits its Columbus.

But not only the planets thus gather, so to speak, electricity for the sun’s support from space; the moon also must do its part, as it rotates in the same manner, subject to the sun, and has its own motion through space. But an examination of the moon shows no atmosphere and no aqueous matter visible to us, and also the singular fact that it constantly presents one side only to the earth. R. Kalley Miller, in his “Romance of Astronomy,” article “The Moon,” says, “After an elaborate analysis, Professor Hausen, of Gotha, found that it could be accounted for only by supposing that the side of the moon nearest us was lighter than the other, and hence that its center of gravity was not at its center of figure, but considerably nearer the side of it which is always turned away from us. He calculates the distance between these centers to be nearly thirty-five miles, evidently a most important eccentricity, when we remember that the radius of the moon is little over a thousand miles. It must have been produced by some great internal convulsion after the moon assumed its solid state; but the forces required to produce this disruption are less than might at first sight appear necessary, owing to the fact that the force of gravitation and the weight of matter are six times less at the moon than with us.” Those who are fond of the so-called “Argument of Design” will be gratified to learn that, if the moon had a rotation upon its ownaxis similar to that of the earth, all life—past, present or future—would have been impossible on that satellite or planet; and that, on the contrary,—provided she always turns the same side of her surface to the earth,—it is quite possible that air, water, and life may exist, or may have existed, on the opposite side of the moon, but not otherwise. In fact, air and water must now exist on the opposite side; and, since her whole supply will thus be condensed upon half her surface or less, even with her small force of gravity, it may be quite sufficient in quantity and density for the support of animal, vegetable, or even human life. By reason of this difference in the lunar center of gravity, the side presented to the earth in physical position is similar to the summit of a mountain upon the earth’s surface two hundred miles high, and surely we would not expect to find much air or water or life at that altitude. But the opposite side would resemble a champagne country at the foot of this enormous mountain, and might be well fitted for human existence. Now, we know that similar electricities repel each other, and air or gases charged with similar electricities are equally self-repellent. Professor Tyndall, in his “Lessons in Electricity,” says, “The electricity escaping from a point or flame into the air renders the air self-repulsive. The consequence is, that when the hand is placed over a point mounted on the prime conductor of a good machine, a cold blast is distinctly felt …. The blast is called the ‘electric wind.’ Wilson moved bodies by its action; Faraday caused it to depressthe surface of a liquid; Hamilton employed the reaction of the electric wind to make pointed wires rotate. The wind was also found to promote evaporation.”

Fig. 1, mutual repulsion of similarly electrified pith-balls; 2, the electrical windmill, atmospheric repulsion; 3, repulsion of a flame by electricity; 4, electrical distribution around an oval conductor; 5, mutual attraction of opposite electricities; 5a, mutual repulsion of similar electricities; 6, mutual repulsion of electrospheres of earth and moon; 7, mutual repulsion of electrospheres of sun and comet.

Fig. 1, mutual repulsion of similarly electrified pith-balls; 2, the electrical windmill, atmospheric repulsion; 3, repulsion of a flame by electricity; 4, electrical distribution around an oval conductor; 5, mutual attraction of opposite electricities; 5a, mutual repulsion of similar electricities; 6, mutual repulsion of electrospheres of earth and moon; 7, mutual repulsion of electrospheres of sun and comet.

While electrical repulsion is doubtless analogous to, and correlative with, the attraction of gravitation, this force, and even gravity itself, has been sometimes interpreted as derived from the mutually interacting molecules of space itself. We may even learn somewhat of how such repulsions of similar and attractions of opposite electrospheres might occur. We constantly speak of positive and negative electricity as though these were different fluids, but such expressions are employed only in the same manner as the analogous terms, heat and cold. We know, of course, that cold is the relative absence of heat, the dividing line being not a fixed, but a constantly changing one, so that one body is cold to another by reason of relative, and not absolute, deprivation of heat. It is well known, however, that cold, which is purely a negative state, manifests the same apparent radiant energy as heat. A vessel near an iceberg is exposed to a wave of cold, precisely as of heat from a heated body at the same distance. This, of course, is due to abstraction and not to increment. All space being occupied by attenuated matter in a state of unstable electrical equilibrium, as we say, which simply means a condition ready to be raised or lowered in tension by absorption from or into outside media, all concrete bodies floating in that space must have an electrical potentialeither equal to, or higher, or else lower than that of their surrounding space. A solitary body in space, if we can conceive of such, in either a higher or lower state of electrical tension, would be drawn upon from all sides to equalize the distribution and restore the general average. But if two bodies occupy the same field, and are widely different from each other in electrical potential, one higher and the other lower than that of space, this distribution will be towards each other, and must be manifested by mutual attraction. But if, on the contrary, these two bodies are both equally higher or lower than the spatial average, they have nothing to give to each other, but have this difference to give to or receive only from outer space, and hence they will be drawn apart or, as we say, mutually repelled. The case is similar to what we see in the case of bodies of water at various levels. Suppose there be a lake of a fixed level, and communicating with it and with each other, by open channels, two ponds of water occupying an island in the middle of the lake. If one of these ponds be higher in level and the other lower than the lake, their waters will rapidly converge, the higher flowing into the lower; but if both are at the same level, and higher than the lake, they will flow apart into the lake. Or, if both are at the same level, and lower than the lake, the water of the latter will equally flow from outside into both ponds, and their waters will still be held separate from each other. The analogies of these various levels may be pursued to any desired extent, as electrical tensionsfind their most exact analogies in the pressures of bodies of water at different levels and of different quantities, and these analogies are those most constantly used in the interpretation of such electrical phenomena.

The great electrical activity of the electrospheres of the earth and moon, while they discharge their tremendous currents directly into the sun, at the same time must cause their similarly electrified atmospheres to mutually repel each other, while gravity continues to operate to maintain the earth and moon at their fixed distances from each other, and to retain their gaseous envelopes around their own bodies. The result must be that these similarly electrified atmospheres repel each other with a force proportioned to their masses of atmosphere and the intensity of the electricities of each. The moon’s axial rotation being completed but once in twenty-eight days, and that of the earth once in each day, and the moon’s mass and volume being so much less than those of the earth, whatever of electrified air or moisture she may have (and she must have both, proportionate to her attributes) would have been driven as by a cyclone to the opposite side of the moon and there retained. Now, with an atmosphere and water only on one side of the moon, and that the side opposite the earth, it is obvious that a rotation on her axis at all resembling that of the earth would carry every part of her surface, at each complete rotation, from a region of air and moisture into one deprived of both, and in such a condition she would of necessitybe deprived of both life and its possibility; hence, as the laws of nature compel the lunar atmosphere and moisture to reside permanently on the side always opposite the earth, a co-ordinate arrest of the moon’s axial motion with reference to the earth could alone compensate for such a state of things, and, curiously enough, we find as a solitary exception, compared with the planets, that such is the case. The moon unquestionably has both atmosphere and water on its opposite side. In his recent work, “In the High Heavens,” Professor Ball reviews the physical conditions of the other planets as possible abodes of life. He pronounces against the moon because night and day would each be a fortnight in length; but this is surely no objection, for even in Norway and Greenland such nights and days are not uncommon at different seasons, and thousands of human beings, even as at present constituted on earth, spend their lives there in content and happiness. That the moon also would be terribly scorched by the long day and frozen by the long night does not necessarily follow, for the atmosphere of Mars, that author says, “to a large extent mitigates the fierceness with which the sun’s rays would beat down on the globe if it were devoid of such protection.” As the moon’s opposite face must have a double quota both of atmosphere and clouds, the difficulty will be correspondingly less than on Mars; and as for the “lightness” of bodies on the moon, they would probably get along quite as well as mosquitoes and like “birds of prey” in the marshes along our coasts. The author refersconstantly toourbodies; for example, “Couldwelive on a planet like Neptune?” No, we could not; we would be dead before we got there. Nor couldwelive in the bark of a tree, or at the bottom of the ocean, or in a globule of serum; but living beings are found there nevertheless. The principle is that wherever life is possible there we may expect to find life; and surely life is, or has been, or will be possible, not only on the moon, so far as our knowledge of physical conditions can go, but also on some of the other planets. Of course each planet has its life stage, but this applies not only to the earth, but to all the other planets as well, and not only to the planets of our own system, but to those of all other solar systems. Each has had, or will have, its stage in which life is possible, and these planets may be like human habitations, in which whole races at times migrate from one home to another. There is no conceivable reason why this may not be the general law of creation, and every analogy leads us to believe that it is so.

It has been recently announced that, from telescopic observations, the atmosphere of Mars must be at least as attenuated as that among the highest mountainous regions of the earth, if this planet has any atmosphere at all. That it must be far less dense than that of the earth at sea-level is obvious, for the mass and volume of Mars are very much less than those of our own planet; but that Mars is devoid of a gaseous envelope or atmosphere is contrary to what we know of all sidereal physics. The sun, the fixed stars, the comets, the nebulæ, andeven the meteorolithic fragments which fall upon the earth, all show the same elementary chemical constitution as the earth itself, and we cannot believe that Mars alone is differently constituted from every other body we have been able to examine. We have direct evidence, on this planet, of polar snows and their melting away under the sun’s heat; we see the apparent areas of sea and land; it has its moons as the earth has hers, and exhibits all the characteristic phenomena of the earth and other planets. All sidereal bodies that we know of, except, perhaps, our moon, which exception we have fully accounted for, are found to be surrounded by gaseous envelopes or atmospheres of some sort. The sun, the fixed stars, the nuclei of comets, the condensing nebulæ, the planets Jupiter and the earth, which are those under our most direct observation, and even the meteorites, when examined, reveal the presence of many times their own volumes of independent atmospheric gases; and whatever may be the theory of the origin or development of Mars, it must have been subjected to the same influences, the same environment, and the same processes of creation as those of our solar system generally; and that this body alone should possess no gaseous envelope—for the denial of atmosphere denies, at the same time, the presence of any or all surrounding gases—is quite incredible. Only the most positive, direct, and long-continued proofs of such fact could be accepted, and even then the history of all scientific progress shows that what are believed to be facts themselves fluctuate like fancies till, bytheir accumulated force, they solidify into universally accepted demonstration. The fact, moreover, that the atmospheres of the smaller planets are more attenuated than our own and those of the larger ones denser has no bearing, in itself, on the probability of the existence of life on these other planets, for in our own atmosphere oxygen, which is the efficient element, is diluted with four times its quantity of inert nitrogen. These proportions doubtless vary largely in other atmospheres, so that the oxygen may be much richer in some and far poorer, relatively, in others. The mere fact that the presence of nitrogen, probably, and aqueous vapor, certainly, depends on the gravity of the mass of each planet, while the oxygen is due to electrolytic decomposition induced by the combined volume, mass, and rotation, and other causes,—such as the axial inclination of such planets, for example,—renders these variations in the constitution of planetary atmospheres a certainty. As Mars has a diameter much more than one-half that of the earth, and a diurnal rotational period nearly the same, while his mass, which controls the action of gravity, is only about one-ninth that of the earth (see Appleton’s Cyclopædia), it is obvious that his oxygen-gathering power, compared with that for accumulating nitrogen and aqueous vapor, is much higher than that of the earth, and we should expect to find there an attenuated atmosphere very rich in oxygen, and with a relatively smaller proportion of aqueous vapor, or even water, on his surface. Such seem to be the facts as far as observed.

In operating an electric machine the strength of the current is directly proportionate to the speed of rotation,—that is to say, to the velocity of the generating surface; for example, of the Wimshurst induction machine it is stated (page 63, “Electricity in the Service of Man”), “These four-and-one-half inch discharges take placein regular succession at every two and a half turnsof the handle.” It is also a well-established law of electrolysis that “The amount of decomposition effected by the current is in proportion to the current strength.” Professor Ferguson (“Electricity,” page 225) says of the voltameter, an instrument devised by Faraday, and used for testing the strength of currents by the proportionate decomposition of acidulated water, “Mixed gases rise into the tube, andthe quantity of gas given off in a given time measures the strength of the current.” Roughly estimating the diameter of Mars at five-eighths, the surface velocity at three-fifths, and the mass at one-ninth those of the earth, this planet should have an atmosphere containing about sixty per cent. of oxygen and forty of nitrogen, with a barometric pressure at sea-level of about six and one-half inches of mercury. This would be an excellent atmosphere,—about equal in its quota of oxygen for each respiration to that of the higher areas of Persia, a great country for roses. The aqueous vapors lying low and near the surface would serve as a vaporous screen to concentrate and retain the sun’s heat and retard radiation from that planet. Nothing in particular seems to be the matter with Mars.

On the contrary, the mass of Jupiter is so great, and his attraction of gravity so powerful, that it is only by his exceedingly rapid diurnal rotation (once in less than ten hours) that it is possible for him to accumulate any effective percentage of oxygen at all. But there is certainly plenty of water there.

We may approximately compute, in general terms, the proportion of oxygen in the atmospheres of the other planets in the same way. Neptune, it is true, is so far distant from the sun that the solar orb only “appears about the same magnitude as Venus when at its greatest brilliancy, as viewed from the earth,” but we must not forget that “theintensityof the sun’s light would be more than ten thousand times greater than that of Venus” (Professor Dunkin, in “The Midnight Sky”). Unless the moon gathers a portion of the earth’s oxygen (the planetary satellites, like Saturn’s rings, thus constituting in their rotations a constituent part of the planets themselves), the percentage of this gas in her atmosphere must be exceedingly small, for her axial rotation has a period of a whole lunar month, being the same as that of her revolution around the earth as a center.

The absence of apparent atmosphere and moisture from thevisiblelunar surface has already been mentioned and explained. The means by which this fact has been approximately determined are described by Professor Dunkin, in “The Midnight Sky,” as follows: “Among the many proofs of the non-existence of a lunar atmosphere, it maybe mentioned that no water can be seen; at least there is not a sufficient quantity in any one spot so as to be visible from the earth. Again, there are no clouds; for if there were, we should immediately discover them by the variable light and shade which they would produce. But one great proof of the absence of any large amount of vapor being suspended over the lunar surface is the sudden extinction of a star when occulted by the moon. The author has been a constant observer of these phenomena, and, though his experience is of long standing, he has never observed an occultation of a star or planet,especially at the unilluminated edge of a young moon, without having his conviction confirmed that there is no appreciable lunar atmosphere …. Professor Challis has subjected the results of a large number of these observations to a severe mathematical test, but he has not been able to discover the slightest trace of any effect produced by a lunar atmosphere.”

In Appleton’s Cyclopædia, article “The Moon,” it is stated that “Schröter (about 1800) claimed to have discovered indications of vegetation on the surface of the moon. These consist of certain traces of a greenish tint which appear and reappear periodically; much as the white spots covering the polar regions of Mars …. As we are able, under the most favorable conditions, to use upon the moon telescopic powers which have the effect of bringing the satellite to within one hundred and fifty to one hundred and twenty miles of us, we should doubtless notice any such markedchanges on her surface as the passage of the seasons produces, for example, on our own globe.” Very recently (August 12, 1894), it has been stated, Professor Gathmann has observed a peculiar green spot about forty by seventy miles in area near the crater of Tycho Brahe, “on thenorthwestern edgeof the satellite’s upper limb,” which had disappeared twenty-two hours afterwards.

We understand, of course, that the moon’s librations, by the variation of position of the lunar body, enable us to see, at times, around the edge of this satellite somewhat, so that, instead of observing only one-half, we can in this way see nearly six-tenths of her surface, but not at the same time, of course. When the moon is dark it occupies a position between the earth and the sun, and only its opposite face is illuminated. In this position the attraction of solar gravity and the attraction of the electrically opposite solar electrosphere both accumulate their forces upon the moon’s atmosphere in the same line as the repulsion of the earth’s similar electricity, so that the lunar moisture and atmosphere are, at this part of her subordinate orbit, most powerfully forced away from the direction of the earth. As the moon now proceeds towards her first quarter, the terrestrial repulsion drives her atmosphere radially outward, while solar gravity and electrical attraction tend to hold it in the direction of the sun. The result will be an electrospheric libration, so to speak, and the moon’s atmosphere and moisture will be carried around towards its illuminated face and, to someextent, will overlap the area of terrestrial repulsion. But as the moon advances this will gradually diminish, soon cease, and finally be reversed as it again approaches darkness. We can now understand why the green surface, if it really was due to vegetation, appeared along thelunar marginat the time described above, and also that the observation of planetary occultations “at the unilluminated edge of the young moon” was the very worst part of the moon and its orbit in which to look for air or moisture; as the sun’s influence is then directlyaway fromthe unilluminated surface of the moon, and his “pull” would have, in fact, still further denuded the very portion most persistently examined, and where this absence of atmosphere wasespeciallynoted.

When considering the transference of energy from the peripheral regions of the solar system to the center, its conversion there into a new form of molecular force, and its subsequent distribution, we find a curious and instructive parallel in the action of the reflex nervous system of animal life. This system is one in which the brain or other conscious center of nerve-energy takes no part. Tickle the foot of a child, for example, and its whole muscular system is thrown into uncontrollable convulsions of laughter. Here an exciting contact with the terminal filaments of the afferent or sensory nerves is rapidly carried into the local nerve-center of this part of the system,—that is, the sensory column of the spinal cord. This center of ganglionic nerve-matter lies directly against the correspondingmotor mass, both freely communicating with each other. The sensory current passing into its central ganglion undergoes some peculiar change of character, probably one of intensification, such as is observed in the action of the condenser of an electrical machine, through which sensory ganglion, thus raised in potential, it passes to the motor ganglion adjacent, where it is instantly transformed into an entirely different form of energy. The sensory character has now entirely disappeared, and it has been converted into and is flashed forth as motor energy to the different muscles of the body, which are immediately contracted, the violent molecular motion of the fibres being at once converted into muscular motion in mass. The changes are entirely analogous to those we see in the different conversions of energy in our solar system. Considering the surface of the body as a planetary electrosphere, it is acted upon by excitation from without; currents of energy are engendered, which are at once transmitted to the sensory ganglion, corresponding to the hydrogen atmosphere or electrosphere of the sun; intensification of action here ensues, the current passing through this ganglion or atmosphere into the solar body itself, which corresponds to the motor ganglion; both ganglia are now highly excited; the electrical force is converted into the radiant molecular motor energy of heat and light in the sun and muscular excitement in the body, and these are flashed forth and find scope for their action within the body of the subject or upon the surface of the planets, whichlie, like the muscular structure of the body, within the genetic electrosphere where, acted upon from without and by agencies entirely external, moving contact has induced the primary molecular action, which was then instantaneously transferred to the center, there converted into another form, that of motor energy, and thence sent forth to produce action in the muscles of the body in the one case, and in the other upon the planetary bodies and their satellites and other structures which occupy surrounding space.

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