be as visible near the border as the penum-stances have occurred in which the penumbra- it seems to blow hot and cold with bra appeared to be actually in rotation the same breath; for it is difficult to con- round the nucleus, and as the spots are ceive of a gaseous nucleus so highly heated evidently excavations or funnel-shaped cavthat the photosphere is comparatively cool, ities, the most natural inference seems to and yet so dark that the latter is infinitely be that they are due in the main to some more brilliant. descending force. 66 With our limited knowledge, however, But besides the maculæ, the sun's surface of the sun's constitution, it would be pre- sometimes exhibits shining spots known as mature to speak with any confidence as to faculæ. They are more brilliant even than the cause of these interesting phenomena. the surrounding luminous matter. That Much must of course depend upon the final there is some association between these decision (if finality can ever be reached on and the black specks is undeniable: fresuch a point), as to the nature of the solar quently they appear on the outer border of envelopes. In a globe so highly heated as the penumbra, and occasionally they take the sun's nucleus is presumed to be, and the form of resplendent ridges or ravines surrounded as it probably is by atmospheres converging towards a central gulf. When of such extent and complexity, it is certain the ordinary dark spots vanish they are that great disturbances must continually often succeeded by bright ones, and when arise. Whatever may be the mode in the faculæ present themselves alone, this which the wonderful expenditure of radiant circumstance probably indicates that they force is regularly balanced, the progress will shortly be followed by the appearance must unquestionably involve much energetic of some of the black brotherhood on the action, and may be accompanied by many same site. violent commotions. To a spectator, look- There are other curious features also on ing down upon our planet from a more the sun's countenance. Far from possesselevated point than balloon ever reached, a ing a smooth uniform surface, variegated hurricane or tornado, produced by some only with a few beauty-spots, like the ladies slight alteration of temperature, or a thun- of a past generation, his visage is mottled der-storm floating in the lower regions of all over in such a way that it has been comthe air whenever the electrical equilibrium pared to the dotting or graining of an enwas broken, would appear a very frequent graving. It looks," says Father Secchi, and inevitable exhibition. Even if the like a tissue strewn with white points most commonplace breezes could be inked more or less elongated in form and sepaor coloured, so as to become visible to such rated by a net-work, at the crossings of an observer, our atmosphere would seem to which little black holes appear." In the be the seat of incessant turmoil. But in an penumbra, these white bodies seem to arorb where gravity is twenty-eight times as range themselves in lines like filaments conpowerful at the surface as it is here, where verging towards the nucleus, as if striving the pressure of the aërial ocean must be so to shoot across the dark abyss, and then prodigious, and where yet the temperature interlacing with each other, as if eager to of the mass is so elevated, is it any wonder fill up some gash, or coat over some wound if that gaseous envelope should be the thea- in the photosphere. These peculiar aptre of extensive local perturbations? Now, pearances have been compared to riceassuming the existence of an outer atmos- grains by Mr. Stone, to chipped blades of phere encompassing the photosphere, and straw by Mr. Dawes, and to willow-leaves of colder quality than the latter, Messrs. by Mr. Nasmyth. The latter gentleman De la Rue, Stewart, and Loewy suggest that even hinted that they might consist of solid the spots may be produced by a descending bodies; and Sir W. Armstrong, in his adcurrent from the higher regions, which cur- dress to the British Association at Newrent breaking in upon the photosphere chills castle (1863), observed: "The forms are or disperses it, and by its absorbent powers so regular in size and shape as to have led drinks up the rays of light, and so presents to a suggestion from one of our profoundest the spectacle of a dark nucleus. It must philosophers of their being organisms, posbe enough simply to indicate this most sibly even partaking of the nature of life, probable of all explanations, and to point but at all events closely connected with the in confirmation to the spiral-shaped patches heating and vivifying influences of the sun." in which the luminous matter seems to be Upon the strength of this statement, it was sucked in and carried down into a gaping forthwith announced by some imaginative vortex, these formations looking pretty individuals that living beings had been desmuch like cross sections of a whirlpool or cried in the orb, floating like leviathans in water-spout, if viewed from above. In-a luminous sea, and measuring a thousand miles in length by a hundred in breadth!tions in the magnetism of the sun. The Most probably, the peculiarities in question are due in a great measure to the same causes which lead to the production of the spots. On all these points, however, much uncertainty must exist, for want of a clear knowledge of the sun's atmosphere. Sir William Herschel assumed the existence of two envelopes only; the lower consisting of gaseous matter in a non-luminous state; the upper composed of gaseous matter also, but in a flaming or resplendent condition. It is from this superior layer we derive our light and heat; the other was supposed to shield the surface of the sun from the scorching rays of the photosphere. But a third investing ocean at least must also be admitted. The corona which encompasses the body of the orb during total eclipses, like the glory round the head of old saints, shows that there is an exterior envelope mounted upon the photosphere. Mr. Norman Lockyer also concluded, from his spectroscopic researches, that the "red protuberances were due to the heaping up of hydrogen gas, which formed a continuous layer round the sun.* 66 mode in which that body affects the magnetic condition of the earth, says Mr. G. Chambers, "is not analogous to the action of a magnet upon a mass of soft iron placed at a great distance from it," but the influences proceeding from the great luminary do so in a form different from that of magnetic force, and are converted into the latter form of force probably by their action upon the matter of the earth or its atmosphere." And this conclusion is confirmed by Professor W. Thompson, who says that no effect of the sun's action as a magnet is sensible at the earth.* Upon another point connected with the central orb, a very valuable result may be noted. Until recently, if we had asked any school girl what was the distance of the earth from the sun, she would have answered, with the confidence of an itinerant lecturer on the universe, and with the promptitude of a flash of lightning, “95,000,000 of miles." This, in her case, would have been one of the principal fruits of the charge of so many guineas per annum for the use of the globes. If the same question had been propounded to a philosopher, he would have returned the same reply, with a hint as to some odd fractional miles, but with a caution that the calculation was only provisional, and must be taken, like a mer Amongst other interesting questions which have been propounded respecting the sun, it has been asked whether this body does not act as a huge magnet, and produce, in that capacity, all the various mag-chant's account, with a clause of "errors netic phenomena which are manifest upon our earth? excepted." Putting the matter in professional language, he would have intimated That the "king of day" plays the part that the sun's parallax (or the angle subof a great loadstone, and keeps all the tended by the earth's radius when seen from planets in charmed subjection to his author- the sun) was set down as something more ity, is of course a very poetical version of than eight seconds and a-half (8-57), but things, and many a fanciful mind has con- that there were grounds for supposing that jured up a vision of an orrery moved, or at it really amounted to nearly nine seconds least maintained, entirely by magnetism. (8"-95). The difference between these two But without displacing the power or princi- estimates would bring our globe between ple, whatever it may be, which we call at- three and four millions of miles nearer to traction, does the sun, by his direct action, the Giver of Light. Now, the peculiarity excite those magnetic currents which are of the case is, that astronomers have arrived perpetually streaming over our planet, or at this amended result by separate routes, stir up those magnetic storms which some- and for the most part without any definite times break out suddenly and rage over expectation of correcting the error in queswhole continents, though insensible to our tion. When experimenting, for instance, human organs except so far as they are dis-upon the velocity of light, Foucault found closed by the convulsive quiverings of the needle? This point has been carefully investigated, and the conclusion drawn that such terrestrial disturbances are not caused by varia In a paper in the "Philosophical Transactions" for 1869 (Part 159), Mr. Lockyer has very handsomely disclaimed the honour of being the first to announce the continuous character of the envelope known as the chromosphere, and has assigned to Professor Grant, Professor Swan, M. Liais, and others, their share in the merit of this discovery. that its accredited speed must be lowered, and this rendered it necessary to reduce the distance of the sun by the amount just mentioned. In studying the moon's motions, Hanssen showed that the disturbing influ * "Philosophical Transactions," vol. cliii. p. 503, Mr. G. Chambers on "The Nature of the Sun's Magnetic Action upon the Earth." The reader will doubtless perceive that the question here raised is not as to the influence which the orb exerts upon our magnetism by means of its heat or otherwise, but whether it operates as a great loadstone simply. run together into a cluster. Upon the supposition of the sun's motion there must, therefore, be some quarter in the heavens where the stars will seem to be opening out their ranks, and to this we must consequently be speeding; whilst in the opposite region the reverse effect will appear; for there the bright ones will seem to be closing up their array. Such a region was found. Out of fifty-six stars examined by Sir W. Herschel, forty-four showed an apparent proper motion, which could only be explained on the assumption that the sun was journeying towards a given point (y) in the constellation Hercules. Subsequent researches have placed the fact of a translatory movement beyond dispute. This splendid galop is conducted at the rate of nearly five miles per second, or 18,000 per hour! ence of the sun upon our satellite must be | These objects, as we approach them, appear revised to an extent which would involve an to recede from each other as we retire, to alteration to nearly the same amount. The planet Mars has been called upon to furnish further evidence, and Venus, on whose testimony philosophers long relied, has again been put into the witness-box, and agrees with the other deponents almost to the letter. It was, in fact, upon her depositions, taken on the occurrence of the celebrated transit of 1769, when commissioners were sent to examine her in the southern hemisphere, that the standard valuation of the sun's distance was based; and when Mr. Stone went over the calculations, the rectified result indicated a parallax of 8-9, instead of the old one of 8"-57. From this striking coincidence, it may be safely assumed that the distance of the sun from the earth is little more than ninety-one millions of miles (91,300,000, in reality); and when we consider how much astronomical science depends upon the accuracy of its data, it will be admitted that the elucidation of this point by methods so thoroughly independent is a curious as well as a creditable feature in the doings of the age. But to what end? This question involves another. Is the orb travelling in a straight line, or in a curve of prodigious sweep? Is his motion the result of some primitive impulse, or of the combined attraction of the celestial bodies, or of a resistless sumBut whilst the relative distance of the two mons from some distant master-masses; or globes is preserved, it must not be forgotten is the entire host of heaven in ceaseless cirthat the sun is ever in progressive motion cuit around some mysterious centre of through the heavens, as if he were bent gravity? For it is an obvious inference upon some errand of life or death. That that if our sun is thus in movement, the he-lord, as he is, of the system should be subject to the same law of axial rotation as his satellites, may excite no surprise; but that he should be posting headlong through space, encircled by a troop of worlds, some with their worldlings around them, and all engaged in performing their mazy evolutions, is a conception which the mind cannot readily realize. Still more, if all the orbs which we have been accustomed to regard as fixed in their everlasting seats," should partake of the same erratic habits, can we repress the thought that, wide as the celestial plains may be, and spacious as they may appear for purposes of parade merely, yet sooner or later, fearful collisions must ensue, if the whole starry host is perpetually on the wing? Now, theoretically, a movement of translation in space may be inferred from the fact that the sun possesses a movement of rotation. Practically, the question has been put upon a footing of reasonable certainty by Sir W. Herschel, Argelander, Struve, Mädler, and others. Broadly stated, the principle upon which the inquiry was based by the first of these philosophers is familiar to every town pedestrian in the lamps in the streets, and to every country traveller in the trees of an avenue, or the telegraph posts on a railway. VOL. XVII. 752 LIVING AGE. other stars may be nomadic as well. Indeed, the spectroscopic determination of the flight of Sirius by Mr. Huggins affords positive demonstration on this point. But to say whether the path of the sun is rectilineal or orbital surpasses the present powers of the astronomer. Not that it is necessary to assume in the latter case the existence of any central body of surpassing bulk and dignity. The exact point round which millions of stars may revolve may not only be destitute of all signs of imperial importance, but it may not even be indicated by a single handful of matter. Nature does not always set up a memorial to indicate the spots where the most momentous actions are performed: the earth's surface is not pierced by any visible object where the axle of rotation might be supposed to protrude; nor is there any external peculiarity to denote the places where the magnetic poles are to be found; and as little is there any furrow or ridge in the ocean to represent the equatorial belt which divides the two hemispheres. This focal point, however (if such it be), was considered by Struve to lie between the stars and in the group Hercules: Argelander fixed upon Perseus as the empire-constellation of our astral system, whilst Mädler hoisted the royal standard upon the most brilliant of the Pleiads, Alcyone. Here, then, is one of those stupendous facts which seem every now and then to drop down upon us from the firmament with such overpowering effect. Nothing can appear more placid and motionless than yonder silent stars. Let the astronomer gaze at them till he grows grey, and yet he can detect no symptom of disorder in their ranks. But this vast army of worlds is perpetually on the march, its shining battalions never bivouacking for a single night, but steadily pursuing their way across the celestial fields, without waking a single echo throughout the universe. But, figuratively speaking, there is a dark side as well as a bright side to the sun. The very properties which enable it to fill our planet with life appear to deprive it of the privilege of cherishing life upon its own surface. Since spectroscopic research has shown that the body of the orb may be charged with heat of extreme ferocity, it is impossible that organized creatures, even of the most salamandrine qualities, could breathe its scorching atmosphere, or tread its burning marl. It is precisely this hypothesis of an obscure and unheated nucleus, says Mr. Guillemin, which is no longer admissible. 66 L'interposition d'un ecran opaque ou doue d'un tres-faible pouvoir absorbant pour la lumiere et la chaleur, a supposer que l'existence en soit demontree ne prouverait qu'une chose, a savoir, que la noyau interieur ne s'echauffe point par rayonnement. Mais du moment que la photosphere est en contact avec la couche de nuages des penombres elle lui communique force ment sa chaleur par voie de conductibilite; l'enveloppant de toutes parts, elle l'echauffe a la fois par tous les points de sa surface et l'on comprend que le pouvoir de conductibilite fat-il tresfaible a la longue l'equilibre de temperature ne peut etre moindre que celle de la fusion. Les gaz sont de tres-mauvais conducteurs de la chaleur, il est vrai; mais leur conductibilite n'est pas nulle, et en accumulant les siecles on comprend qu'un certain equilibre s'etablisse, par cette seule voie, entre la photosphere et le noyau. N'oublions pas d'ailleurs que les masses gazeuses s'echauffent par convection ou transport, et qu'a moins de supposer l'immobilite dans les couches sous-jacentes la chaleur doit se propager avec rapidite. Or les phenomenes des taches, leurs transformations rapides, les mouvements que ces transformations supposent, soit dans les couches de la photosphere soit dans les couches plus profondes, mettent hors de doute, selon nous, la realite d'un melange incessant de ces couches diverses, et par suite d'un echange continuel de la chaleur dont elles sont douees. Il est donc tout a fait probable que le globe entier du soleil est a une tres haute temperature dans toute sa masse, a une temperature qui depasse celle de la fusion de la plupart des corps simples dont l'analyse spectrale a revele l'existence dans son atmosphere.” In the fact, therefore, of a glowing nucleus, many a fine philosophical dream has received its death-blow. More than one speculator has calculated the prodigious population which our sun could accommodate, and has pictured to himself the wonderful activities of which that globe must be the scene, if everything there were conducted upon a scale of metropolitan magnificence. And verily there are men to whom it will seem a discredit to the system that its noblest orb should be a desert, so far as life is concerned, that its central mass, surpassing in volume the entire troop of planets and satellites not less than 600 times, should be incapable of harbouring any manifestation of that great property which is the glory of our nether world. Let not such good souls despair, however. The sun's turn will doubtless come. Its first forms of life have yet to be born, but the birthday of organization will assuredly arrive; and when its little Oldhamia or Lingula, or whatever character its opening animal productions may assume, shall creep into existence, there will doubtless be great rejoiceing amongst the sons of the morning. Upon what premises, however, can we base such a presumptuous speculation? Chiefly upon the fact that the system exhibits bodies in different stages of development. Take our own globe, for example. It is clear, from the story told by its rocks, and in particular from the igneous character of those which have been ejected from below, that our earth was once in a state of intense heat, as its core may be to the present hour; that it was shrouded in a dense atmosphere of vapour and aërial fluids, and that consequently it was utterly unfit to accommodate the organisms which now swarm upon its surface. It was then, we may assume, what the sun is now. But having cooled down more rapidly than the latter, as it necessarily would having passed through fire and water, in its stormy apprenticeship, and eventually acquired a firm consolidated crust-it opened its doors to life, and creatures came tramping in as they did into the diluvial ark. So it may fare with the solar orb. Finding as we do the same elementary substances there as here, and compelled as we are to believe from the movements of the whole system in one plane and one direction, that there has been a unity of origin and of primitive experience, if we may so speak, it is difficult to suppose that pro cesses which have transpired, or are transpiring in one member of the family may not apply to the rest. The moon, so far as observation extends, is an untenanted orb. In all probability its inherited caloric has been mostly expended, or at least the superficial portion has been dissipated, and the residue lies hid in its interior. Consequently its day of life may have closed, and our beautiful satellite may be but a shining sepulchre and a worn-out world. Perhaps it was only an ephemeron amongst stars? Our turn, also, may come; and when life is waking up in the sun it may be dying out on the earth. Let us not, however, think dolefully of the universe, if we find proofs of change or even symptoms of "decay," for in nature nothing is lost, and life is ever born of death. True Science, like true Philosophy, always gives us more than she takes; and with the same breath that she tells us worlds may cease to palpitate, she tells us also that the forces which gave them all their vitality can never be crushed into nothingness except by the hand of Him from whom they emanated. There are several other points connected with this "soul of surrounding worlds" upon which it would have been pleasant to touch, but narrowing space warns us to conclude, particularly as we devoted some attention to solar phenomena in a recent article on the Language of Light. Before parting, however, from the great luminary, we cannot forbear to remind the reader that we are indebted to this generous orb for light by night as well as by day, for warmth within doors as well as without. We are accustomed to speak of the sun's light and heat as forces actually garnered up in the vegetation of ancient epochs. We look upon our coal strata as cellars in which sunbeams have been locked up for unnumbered ages, in order that they might ultimately be reissued for the benefit of the intelligent tenantry for whom the world was intended. In a certain qualified sense this is perfectly true: coal is unquestionably invested sunshine. The gentle warmth we draw from our domestic fires, the fiercer heat which cooks our food or melts our metals, are the product of the sun's energy exercised upon the earth during some of those silent centuries when the globe was in preparation for man. Strolling through a town lit up by innumerable lamps, or whirled along at the heels of a locomotive, it is a pleasant thought that the emanations of suns which rose and set millions of years ago which rose and set in seeming idleness, and to all appearance in wasted splendour- are now reproduced to enable us to cope with darkness, or to conquer space without moving a muscle. There is something captivating in the thought that the great rector mundi was working for us when as yet there was no sign of man-indeed, no promise of his coming, and with quiet patient labour laying up from day to day those treasures of light and heat which are infinitely more valuable to us than all the gold and diamonds we possess. No one who has studied geological processes can repress a feeling of surprise, perhaps of impatience, at the slow deliberate step with which Nature ever marches up to her goal; but when we think of the sun toiling in lonely splendour to store our planet with fuel-we had almost said with his own. embodied beams - it seems to reconcile us in some degree to the august and awful chronology of the universe. A passing analogy may not be unacceptable. If, in a modified sense, the light of ancient suns may be hoarded up for ages, so may the odour of ancient seas. Some years ago, a writer pointed out to the Academy of Sciences at Paris that the shells of the teredo found in the fossil-wood about Brussels gave out when scratched, or when newly extracted from the soil, a strong scent of the ocean. But of what ocean? Clearly of one on which no human sail had ever been spread, for it belonged to the distant cocene era. After countless centuries had elapsed, the subtle aroma of that prehistoric sea was released from its imprisonment, and played upon nostrils fashioned in this our nineteenth century, as if it were the perfume of a flower plucked yesterday. It brings the ages together to find that from a fossil comes forth fragrance which has been impounded for millions of years, and that from our coal measures we can draw matter which may be called the solidified sunshine of the world's youth. In conclusion, let us add that the greatest of physical paradoxes is the sunbeam. It is the most potent and versatile force we have, and yet it behaves itself like the gentlest and most accommodating. Nothing can fall more softly and more silently upon the earth than the rays of our great luminary - not even the feathery flakes of snow which thread their way through the atmosphere, as if they were too filmy to yield to the demands of gravity like grosser things. The most delicate slip of gold leaf, exposed as a target to the sun's shafts, is not stirred to the extent of a hair, though an infant's faintest sigh would set it into tremulous motion. The tenderest of human organs- the apple of the eye — though pierced and buffeted each day by thousands |