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unlikely than the existence of a flat ring round the globe of Saturn, or of a group of thirty-five minute planetoid bodies within the precincts of the solar system. Under these circumstances, it is clear that the beam inclines very considerably from the side of the essayist to that of the plurality of firmamental star schemes. But there is yet another consideration, so weighty in itself, that we think it entirely sets the question at rest, and decides it against the essayist, although it does not seem to have occurred to any of the controversialists who have answered the author of the Essay.

In this reasoning we fully concur. There can be no doubt whatever that if the ring of Saturn had never been seen, and if the thirty-four planetoids had never been detected between Mars and Jupiter, the assumption, that either such a ring or such a group of miniature planets could exist in the universe, would have been deemed so improbable as to be rash and fantastic in the highest degree. Yet there the ring and planetoids are, and each instance stands alone, so far as observation allows us to The light of the filmy transparent comet judge, in the vast realms of space. There is so faint, that as the cometic luminosity really could be nothing more extraordi- travels away from the earth, it is lost to nary in such a distribution of remote star-sight long before its dimensions have been clusters, as the appearance of the Magel- dwindled down to an unappreciable mealanic clouds indicates, than there is in these sure. It disappears as a perceptible body, unquestionable instances of unique and ex- or "goes out" from the failure of its light, ceptional arrangement. We think, there- and not from the loss of its size. Yet the fore, that the difficulty sagaciously sug- greatest distance at which the cometic gested by Sir John Herschel is fairly met; wanderers are ever seen, as Sir David and that Captain Jacob has shown, in the Brewster strikingly puts it, "falls short first place, that the essayist has conside- of the distance of the nearest fixed star by rably exaggerated the points upon which nine million of millions of miles." The he mainly rests his cause in this particular nearest nebulæ, on the other hand, at the phase of his arguments; and, in the second lowest estimate are considerably further place, that the improbability, if admitted off than the nearest fixed star, and at that in its strongest form, is far from being distance not only retain their brightness, conclusive in regard to the point the es- but even become more brilliant in proporsayist contends for. In our apprehension, tion as larger telescopes are directed tothe matter stands thus: on the one side wards them, instead of getting paler and there is Sir John Herschel, holding the more diffuse, às cometic luminosity does doctrine that nebulæ are remote firma- under the same circumstances. Is it conments in a general sense, but suggesting ceivable, then, that a filmy luminosity that caution upon the exceptional evidence of vanishes from faintness within the realms the Magellanic clouds. On the other side, of the planetary scheme, remains visible there are the facts that more and more nine million of millions of times further off, nebulæ, before deemed irresolvable, are when "ten thousand times more thin and constantly being resolved into distinct star- rare?" Earnestly, but with all due regroups, with every fresh increase of opti- spect for the opinions and authority of cal power brought to bear in the examin- the essayist, we submit that nothing but tion; that this exceptional instance, which "a conviction that has gradually grown "gives" Sir John Herschel "pause," has from various trains of speculation" could never been subjected to the scrutiny of the maintain such a theory. There is quite great cloud-resolver, Lord Rosse's magni- enough in this peculiarity of nebulous ficent instrument; that Lord Rosse's own light, apart from the fact of its resolvabilexperience, he having really the best prac-ity into stars, incontrovertibly to establish tical right of any living man to be admit- its entire distinctness from the nature of ted as an authority in the case, induces comets. Whatever it may be, this at least him to believe that, with sufficient optical is clear, it is not cometic luminosity ten power, all the nebule of the sky would thousand times refined. be converted into stars; and that if the exceptional instance of the Magellanic clouds were proved, it still allows the possibility of an alternative which is not more

VOL. XXXVII.-NO. I.

Having thus carefully and fairly weighed the geological and nebular evidence adduced by the essayist, and found it wanting, we proceed to listen to what he has

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in them and in their contemporaries. Nor are we yet called upon to withdraw from them our sympathy, or entitled to contradict their conjectimes have given us, the extreme tenuity of much ture. But all the knowledge that the succeeding of the luminous matter in the skies, the existence of gyratory motion among the stars, quite different from planetary systems; the appearance of changes in stars quite inconsistent with such permanent systems; the disclosures of the history of our own planet, as one in which changes have constantly been going on; the certainty that by far it has been tenanted by creatures entirely differthe greater part of the duration of its existence

a persuasiveness, to the belief of inhabitants in worlds appended to each star; the impossibility which appears, on the gravest consideration, of transferring to other worlds such interests as belong to our own race in this world; all these conthat old and arbitrary conjecture from growing siderations should, it would seem, have prevented up, among a generation professing philosophical caution and scientific discipline, into a settled belief." (Plurality &c., p. 266.)

to urge in regard to the fixed stars. The tenor of his remarks in this direction is that amongst the sidereal host there are individuals in which changes have occurred, or continue to recur periodically, in the intrinsic brilliancy or in the color of their light; this implies to him that those stars are not in the permanent condition in which the sun is, and which alone is compatible with the necessities of a system of worlds, but that they are in an unsettled state and in the transition of progress. The fixed stars are, it is true, self-ent from those which give an interest, and thence luminous, like the sun, but the nebulæ and comets are also self-luminous, and it is with them the true analogy lies. The stars are simply nebulæ in forward stages of maturation, advancing perhaps towards the condition of planetary systems, of which the solar one is the only perfected specimen. Periodical variations of brilliancy, such as are illustrated in Algol, suggest, not that there are large opaque bodies of a planetary nature revolving round the central source of light, but that the light itself has not yet assumed the spherical form, and is an oblong revolving nebular mass, of which some parts are cooled down, and have become opaque, and therefore intercept the rays emitted from the rest when they pass before them. In the case of Algol, it is known that the period of the intermissions of brilliancy is growing gradually shorter. This is not a cosmical irregularity of elliptical movement, as Herschel supposed, carrying its own compensation with it, and promising, after a time, a return to some original measure, but it is a yet further indication that the star is a crude nebular mass in process of condensation. Even the facts that have been ascertained in relation to the relative distances and movements of the binary stars point to the impossibility of their having any connection with worlds. Some of them confessedly have their constituents nearer together than the breadths of space included in the dimensions of the solar system, and if there were planetary orbs circling round either constituent, they would of necessity pass so near to the attracting mass of the other as to render it impossible to be sustained in any regular and orderly course.

"That Copernicus, that Galileo, that Kepler,

should believe the stars to be suns in
every sense
of the term, was a natural result of the expansion
of thought which their great discoveries produced

But again we submit that "succeeding times have also given us" two or three particulars in the way of knowledge, which are strictly relevant to the matter under consideration, but which nevertheless the essayist has altogether omitted from his enumeration. We know that the sun would appear to get smaller and smaller, if we were further and further removed from it, and that at last, on account of its intensity of brilliancy, it would seem a shining point of inappreciable dimensions. Its size would of necessity escape from the perceptive abilities of the organ of vision long before the light emitted from it became too faint to excite sensation in its nerves. We know that the stars are at distances so remote, that if the sun were there too, it would be sufficiently far to have lost its size, and to have been converted into a shining point, and consequently we know that if the stars are like the sun, they would present just the appearance they do, at the distance at which they are placed. On the other hand, if the stars be not like the sun, then we do not know what they can be, for there is nothing in this "train of speculation" of the essayist that furnishes any positive information upon the matter which can in the slightest degree pretend to take the place of the notion he endeavors to sweep away. For ourselves, we confess that these common-sense considerations appear to us to possess immeasurably more weight than all his remarks. The variable and

thing but water. Its oblate form is just such a figure as a huge drop of water would assume if in very rapid rotation. The belts of cloud, which sweep transversely across its broad face, prove that it has water about it in abundance. So that taking into account the "bottomless waters" of this planet, the great force with which its vast mass must gravitatingly draw down whatever is placed near its surface, and the small amount of solar influence which, at its remote distance, it receives, it becomes clear that any inhabitants that belong to it, must possess only the very lowest forms of organization and life. As there are no solid substances, like bone, in the planet, they must be devoid of skeletons. As the temperature is very depressed, they must be very sluggish and inactive in all their functions and operations. Jupiter comes out, therefore, a mere spherical mass of water, with a few cinders in the midst, and a damp drapery of cloud and mist drawn around it; and with, at the best, a population of boneless, pulpy, glutinous monsters rolling about in its watery recesses; or, it is an oblately spherical lump of ice, with a few shallow pools of water here and there upon its surface, and entirely devoid even of pulpy monstrous life.

unsettled condition of certain stars really | ter, and therefore most probably is noproves nothing more than that those few exceptional luminaries are unlike to their neighbors. It does not afford even a shadow of a reason for the assumption that fixed stars in general are unlike the sun. Obviously the irregularities of a few individuals in any community cannot be laid to the account of the greater number that are of a staid and orderly character. The essayist finds the comparatively close neighborhood of the constituents of the binary stars incompatible with the supposition that there are planetary orbs revolving about them in safety. Sir John Herschel, however, holds a different opinion in this matter; for while considering the probability of such a supposition being in accordance with fact, he writes, "unless closely nestled under the protecting wing of their immediate superior, the sweep of their other sun, in its perihelion passage round their own, might carry them off, or whirl them into orbits utterly incompatible with the conditions necessary for the existence of their inhabitants." Captain Jacob, too, points out how very possible it is that planetary spheres may revolve in orbits so large that they inclose within them both the constituents of a binary star, whose common centre of gravitation would thus become the general gravitation-centre of the system. Under such an arrangement there would be irregularities of elliptical movement running in cycles, and returning through compensatory influences upon themselves, but there would be no such dangerous interferences as those which are particularised by the essayist as incidental to the other case. In fine, we are constrained to decide against the essayist upon his sidereal argument.

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Saturn, with its liquid and vaporous rings, with its cork-like lightness, and its illumination ninety times less than the Earth's, is in the same category with Jupiter, except only that it is in every respect worse off; so that its pulpy monsters, in its icy waters, are too sluggish to be even "deemed alive." The asteroids contained in the spaces between Jupiter and Mars, are avowedly too small to be peopled with living things. But they are We now at length come to that portion nevertheless highly important to the arguof the Essay which really most closely ment in one sense. There are thirty-four concerns the question at issue, although of them, and therefore at least the " its author does not seem to have viewed it jority of the planets are uninhabited.” in this light,—namely, the consideration of Mars, a comparatively near neigbor to the the condition of the planets which are as- Earth, certainly does approach in a degree sociated with the Earth in its subordina- to its state of physical existence. It is of tion to the solar mass. Here the essayist nearly the same size, and is composed of finds warranty no less strong for rejecting substance of analogous density. It has, entirely the existence of other worlds. too, its clouds and snow, and possibly it Neptune has not light enough to be of may have inhabitants to boot. But it has any available use in the service of organi- longer years and a colder climate than the zation. Its sun-derived light and heat are Earth. It has, too, really a smaller mass, 900 times less than the Earth's. Jupiter and "perhaps no atmospheric investment;" has a density not greater than it would therefore, after all, its inhabitants can only have if it were entirely composed of wa-be of the rudimentary nature of corallines

or molluscs, or possibly of saurians and iguanodons; or, as it is smaller than the Earth, like the Moon, and also like it, near the Earth, it is also possibly, like it, without inhabitants. The moon has neither atmosphere nor water, therefore it is not inhabited. This, however, has great significance. It is the only orb which is near enough to be fairly within the reach of human observation. As therefore the only celestial sphere that can be scrutinized is uninhabited, the high probability is, that neither are any of the rest. Venus, almost as large, and almost as heavy as the Earth, presents no trace of any gaseous atmosphere; neither can any indications of irregularity of surface be discovered. It seems to be a smooth glassy sphere, annealed by slow cooling" in its close propinquity to the Sun, and could not possibly be peopled by any forms of living creatures, unless by microscopic animalcules armed with siliceous coverings that are indestructible by heat. Nothing can be discerned regarding Mercury, but of course it can not be the home of any thing but salamanders.

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Having thus completed his detailed examination of the several constituents of the planetary scheme, the essayist proceeds to the construction of his own the

is placed, and life is developed. At this distance from the Sun, the worldmaking powers are efficacious. Farther out they have ceased to be so, and have only been able to "roll up into neat balls" the vapors and liquids that would otherwise have wandered about in the way, or to form the smaller planetoids, the satellites, and the congeners of these, the meteoric stones. At this distance from the solar focus, there was not heat enough to melt these smaller fragments together into one larger sphere, or to keep them in a gaseous state until the mutual attraction of the several parts had drawn them together into a mass, which was ultimately capable of solidifying into a sphere.

"And thus all these phenomena coucur in making it appear probable that the Earth is placed in that region of the solar system in which the planet-forming powers are most vigorous and potent; between the region of permanent nebulous shreds and specks of planetary matter, such as are vapor within its orbit and the region of mere the satellites and the planetoidal group in the outer region. And from these views, finally, it follows, that the Earth is really the largest planetary body in the solar system. The vast globes of Jupiter and Saturn, Uranus and Neptune, which roll far above her, are still only huge masses of cloud pro-and vapor, water and air, which from their enormous size are ponderous enough to retain round ory of the solar system, which is succinctly them a body of small satellites, perhaps, in some this. Originally its material formed one degree at least, solid; and which have, perhaps, confused and blended mass, but when this a small similar lump, or a few similar lumps, of confusion was reduced to order, the vapors planetary matter at the centre of their watery and water were principally driven off to glope. The Earth is really the domestic hearth the outer boundary of the system, and of the solar system, adjusted between the hot and the solids were principally retained near fiery haze on one side, the cold and watery vapor the focus of the solar heat. The Earth, mestic hearth, a seat of habitation; and in this on the other. The region is only fit to be a doin the mean time, was moulded in mid-re-region is placed the largest solid globe of our gion between these extremes, and consequently combined in itself the attributes of both. This made it at once fit to become the residence of living creatures. It had solid ground for them to stand on,air for them to breathe,-water to nourish their vegetables,-condensed substance to furnish the textures of their bodies,-a due supply of light, heat, and force of gravity, for their service. The Earth is the temperate zone of the solar system. Mercury and Venus are still immersed in mother-light and mother-fire in which their first crystallization was effected. They are in the nebular region indicated by the presence of the zodiacal light, which is uninhabitable in virtue of its chaotic nebulosity. But where this zodiacal nebulosity ends, the largest real orb of the system

system; and on this globe, by a series of creative operations, entirely different from any of those which separated the solid from the vaporous, the cold from the hot, the moist from the dry, have been established in succession plants, and animals, and man. So that the habitation has been occupied, the domestic hearth has been surrounded by its family, the fitnesses so wonderfully combined have been employed, and the Earth alone, of all the parts of the frame which revolves round the sun, has become a world." (P. 308.)

Such are the conclusions at which a mind, evidently of a high intellectual order, and well versed in the discipline of philosophy, professes itself to have arrived. The cautious inquirer, who is surprised that the "old and arbitrary conjecture" regarding the existence of a plurality of worlds should have grown into a

settled belief amongst a scientific generation, nevertheless finds sufficient scientific evidence for the opinion that nebulæ, which upon the lowest possible estimate, are more than 200,000 times one hundred and ninety millions of miles distant, and which are still visible as luminous objects at that enormous distance, are nevertheless whiffs of mist thousands of times rarer than a comet's tail; that the fixed stars are masses of like luminosity a little more condensed; that Jupiter is a great drop of water, and Venus a ball of annealed glass; and that, in general terms, the planets, stars, and nebulæ are waste lumps and vapors which have flown off from the wheel of the Great Workman when he turned the single round world of the universe, which he has accorded to man for his dwelling-place. We confess that the so-called scientific evidence appears to us to be such a mass of gratuitous and unsupported assumption, that we should find it difficult in the extreme to reconcile it with the subtle power and information which are unquestionably displayed in other pages of this book, did we not bear in mind that the work is avowedly, as we have already pointed out, a peculiar view of modern science, adopted for the support of a preconceived notion entertained upon distinct grounds; that, in other words, it is not an exposition of the way in which the author has been led through the successive stages of philosothrough the successive stages of philosophic induction to certain opinions and views, but a one-sided defence of opinions and views that have been formed upon different considerations.

Neptune, according to the essayist, can not be inhabited, because it receives nine hundred times less light and heat from the sun than the Earth does. Upon this Captain Jacob remarks:

"Neptune, then, is not quite so badly off as is represented; his daylight is probably superior to that of a dull day in London, and his moonlight not much inferior to that of a young moon with us. As to his heat, as above remarked, we do not know by what causes it may be modified; some heat he must receive from the Sun, and his specific heat may be greater than ours. We know from geological evidence that the Earth in former eras enjoyed a warmer climate than at present; and the greater bulk of the four outer planets renders it probable that they may have cooled more slowly, and may therefore, at the present time, be considerably warmer than the Earth. As regards Jupiter and Saturn, this is something more than mere conjecture; for the former appears to be en

tirely enveloped in clouds, with the exception of a few spaces near his equator, through which alone his dark body is visible, and which constitute his there being no perceptible opening in his envelope. belts; while Saturn is even more closely covered, This state of things would indicate a high temperature as well as a dense atmosphere." (Jacob, p. 27.)

Professor Baden Powell also writes:

"On this point there is one consideration often not sufficiently attended to. The solar heat is entirely of a peculiar nature, unlike that which emanates from a terrestrial hot body simply cooling or radiating its heat. The solar heat is not derived from the mere cooling of the sun, but is conveyed, as it were, in the rays of light, as a vehicle, and never becomes sensible as heat till the light is absorbed. It is, therefore, probable that these rays may owe their extrication from the sun to some other cause than elevation of temperature. It is an effect elicited or produced by the action of certain rays which are no more properly rays of heat than a galvanic current can be callexcites heat." (Baden Powell, p. 212.) ed a current of heat, because, when stopped, it

We can have no doubt that London

might be inhabited even if it were for ber fog, and that the Arctic regions might ever enveloped in the gloom of a Novembe the residence of vital organization,

even if they never caught a gleam of sunlight at all, under a very slight modification of material arrangements; consequently we think that the argument of the essayist with regard to the most remote known planet of the solar system is met and disposed of by his opponents. A slightly higher internal temperature in climate as genial as that of many of the the sphere of Neptune, might render its temperate regions of the Earth; and, as an eye with a pupil sufficiently enlarged, Sir David Brewster has well remarked,

or with a nerve whose sensibilities were

sufficiently exalted, would make the Neptunian sunshine practically as bright as the terrestrial sunshine is.

The essayist holds that Jupiter is a sphere of water because its specific density is about the same with water, and because it wears the form wich a rotating sphere of water would have.

"It is tolerably certain that the density of Jupiter is not greater than it would be if his entire globe were composed of water; making allowance for the compression which the interior parts would suffer by the pressure of the parts superincumbent upon them. We might, there

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