And now we have reached a point at which the intellect is forced, again, to struggle against its propensity for analogical inference against its monomaniac grasping at the infinite. Moons have been seen revolving about planets; planets about stars; and the poetical instinct of humanity-its instinct of the symmetrical, if the symmetry be but a symmetry of surface:-this instinct, which the Soul, not only of Man but of all created beings, took up, in the beginning, from the geometrical basis of the Universal irradiation--impels us to the fancy of an endless extension of this system of cycles. Closing our eyes equally to deduction and induction, we insist upon imagining a revolution of all the orbs of the Galaxy about some gigantic globe which we take to be the central pivot of the whole. Each cluster in the great cluster of clusters is imagined, of course, to be similarly supplied and constructed; while, that the "analogy" may be wanting at no point, we go on to conceive these clusters themselves, again, as revolving about some still more august sphere;-this latter, still again, with its encircling clusters, as but one of a yet more magnificent series of agglomerations, gyrating about yet another orb central to them -some orb still more unspeakably sublime-some orb, let us rather say, of infinite sublimity endlessly multiplied by the infinitely sublime. Such are the conditions, continued in perpetuity, which the voice of what some people term "analogy" calls upon the Fancy to depict and the Reason to contemplate, if possible, without becoming dissatisfied with the picture. Such, in general, are the interminable gyrations beyond gyration which we have been instructed by Philosophy to comprehend and to account for, at least in the best manner we can. Now and then, however, a philosopher proper--one whose frenzy takes a very determinate turn--whose genius, to speak more reverentially, has a stronglypronounced washer-womanish bias, doing every thing up by the dozen-enables us to see precisely that point out of sight, at which the revolutionary processes in question do, and of right ought to, come to an end.

It is hardly worth while, perhaps, even to sneer at the reveries of Fourrier :--but much has been said, latterly, of the hypothesis of Mädler--that there exists, in the centre of the Galaxy, a stupendous globe about which all the systems of the cluster revolve.

The period of our own, indeed, has been stated--117 millions of years.

That our Sun has a motion in space, independently of its rotation, and revolution about the system's centre of gravity, has long been suspected. This motion, granting it to exist, would be manifested perspectively. The stars in that firmamental region which we were leaving behind us, would, in a very long series of years, become crowded; those in the opposite quarter, scattered. Now, by means of astronomical History, we ascertain, cloudily, that some such phænomena have occurred. On this ground it has been declared that our system is moving to a point in the heavens diametrically opposite the star Zeta Herculis:-but this inference is, perhaps, the maximum to which we have any logical right. Mädler, however, has gone so far as to designate a particular star, Alcyone in the Pleiades, as being at or about the very spot around which a general revolution is performed.

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Now, since by "analogy" we are led, in the first instance, to these dreams, it is no more than proper that we should abide by analogy, at least in some measure, during their development; and that analogy which suggests the revolution, suggests at the same time a central orb about which it should be performed :astronomer was consistent. This central orb, however, should, dynamically, be greater than all the orbs, taken together, which surround it. Of these there are about 100 millions. "Why, then," it was of course demanded, "do we not see this vast central sunleast equal in mass to 100 millions of such suns as ours-why do we not see it—we, especially, who occupy the mid region of the cluster-the very locality near which, at all events, must be situated this incomparable star?" The reply was ready-" It must be nonluminous, as are our planets." Here, then, to suit a purpose, analogy is suddenly let fall. "Not so," it may be said "we know that non-luminous suns actually exist." It is true that we have reason at least for supposing so; but we have certainly no reason whatever for supposing that the non-luminous suns in question are encircled by luminous suns, while these again are surrounded by non-luminous planets:-and it is precisely all this with which Mädler is called upon to find any thing analogous in the heavens-for it is precisely all this which he imagines in the case of the Galaxy.

Admitting the thing to be so, we cannot help here picturing to ourselves how sad a puzzle the why is it so must prove to all à priori philosophers.

But granting, in the very teeth of analogy and of every thing else, the non-luminosity of the vast central orb, we may still inquire how this orb, so enormous, could fail of being rendered visible by the flood of light thrown upon it from the 100 million of glorious suns glaring in all directions about it. Upon the urg ing of this question, the idea of an actually solid central sur appears, in some measure, to have been abandoned; and speculation proceeded to assert that the systems of the cluster perform their revolutions merely about an immaterial centre of gravity common to all. Here again then, to suit a purpose, analogy is let fall. The planets of our system revolve, it is true, about a common centre of gravity; but they do this in connexion with, and in consequence of, a material sun whose mass more than counterbalances the rest of the system.

The mathematical circle is a curve composed of an infinity of straight lines. But this idea of the circle—an idea which, in view of all ordinary geometry, is merely the mathematical, as contradistinguished from the practical, idea-is, in sober fact, the practical conception which alone we have any right to entertain in regard to the majestic circle with which we have to deal, at least in fancy, when we suppose our system revolving about a point in the centre of the Galaxy. Let the most vigorous of human imaginations attempt but to take a single step towards the comprehension of a sweep so ineffable! It would scarcely be paradoxical to say that a flash of lightning itself, travelling forever upon the circumference of this unutterable circle, would still, forever, be travelling in a straight line. That the path of our Sun in such an orbit would, to any human perception, deviate in the slightest degree from a straight line, even in a million of years, is a proposition not to be entertained :--yet we are required to believe that a curvature has become apparent during the brief period of our astronomical history-during a mere point--during the utter nothingness of two or three thousand years.

It may be said that Mädler has really ascertained a curvature in the direction of our system's now well established progress

through Space. Admitting, if necessary, this fact to be in reality such, I maintain that nothing is thereby shown except the reality of this fact-the fact of a curvature. For its thorough determination, ages will be required; and, when determined, it will be found indicative of some binary or other multiple relation between our Sun and some one or more of the proximate stars. I hazard nothing however, in predicting, that, after the lapse of many centuries, all efforts at determining the path of our Sun through Space, will be abandoned as fruitless. This is easily conceivable when we look at the infinity of perturbation it must experience, from its perpetually-shifting relations with other orbs, in the common approach of all to the nucleus of the Galaxy.

But in examining other "nebula" than that of the Milky Way -in surveying, generally, the clusters which overspread the heavens—do we or do we not find confirmation of Mädler's hypothesis? We do not. The forms of the clusters are exceedingly diverse when casually viewed; but on close inspection, through powerful telescopes, we recognise the sphere, very distinctly, as at least the proximate form of all-their constitution, in general, being at variance with the idea of revolution about a common centre.

"It is difficult," says Sir John Herschel, "to form any conception of the dynamical state of such systems. On one hand, without a rotary motion and a centrifugal force, it is hardly possible not to regard them as in a state of progressive collapse. On the other, granting such a motion and such a force, we find it no less difficult to reconcile their forms with the rotation of the whole system [meaning cluster] around any single axis, without which internal collision would appear to be inevitable."

Some remarks lately made about the "nebula" by Dr. Nichol, in taking quite a different view of the cosmical conditions from taken in this Discourse-have a very peculiar applicability to the point now at issue. He says:

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"When our greatest telescopes are brought to bear upon them, we find that those which were thought to be irregular, are not so; they approach nearer to a globe. Here is one that looked oval; but Lord Rosse's telescope brought it into a circle . . . . Now there occurs a very remarkable circumstance in reference to these comparatively sweeping circular masses of nebulæ. We find they

are not entirely circular, but the reverse; and that all around them, on every side, there are volumes of stars, stretching out apparently as if they were rushing towards a great central mass in consequence of the action of some great power."

Were I to describe, in my own words, what must necessarily be the existing condition of each nebula on the hypothesis that all matter is, as I suggest, now returning to its original Unity, I should simply be going over, nearly verbatim, the language here employed by Dr. Nichol, without the faintest suspicion of that stupendous truth which is the key to these nebular phænomena.

And here let me fortify my position still farther, by the voice of a greater than Mädler-of one, moreover, to whom all the data of Mädler have long been familiar things, carefully and thoroughly considered. Referring to the elaborate calculations of Argelander-the very researches which form Mädler's basisHumboldt, whose generalizing powers have never, perhaps, been equalled, has the following observation :

"When we regard the real, proper, or non-perspective motions of the stars, we find many groups of them moving in opposite directions; and the data as yet in hand render it not necessary, at least, to conceive that the systems composing the Milky Way, or the clusters, generally, composing the Universe, are revolving about any particular centre unknown, whether luminous or nonluminous. It is but Man's longing for a fundamental First Cause, that impels both his intellect and fancy to the adoption of such an hypothesis."

*I must be understood as denying, especially, only the revolutionary portion of Mädler's hypothesis. Of course, if no great central orb exists now in our cluster, such will exist hereafter. Whenever existing, it will be merely the nucleus of the consolidation.

Betrachtet man die nicht perspectivischen eigenen Bewegungen der Sterne, so scheinen viele gruppenweise in ihrer Richtung entgegengesetzt; und die bisher gesammelten Thatsachen machen es auf's wenigste nicht nothwendig, anzunehmen, dass alle Theile unserer Sternenschicht oder gar de! gesammten Sterneninseln, welche den Weltraum füllen, sich um einen grossen, unbekannten, leuchtenden oder, dunkeln Centralkörper bewegen. Das Streben nach den letzten und höchsten Grundursachen macht freilich die reflectirende Thätigkeit des Menschen, wie seine Phantasie, zu einer solchen