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before you the bony blushing little rose-bud, and the respectable 'mediæval' full-blown rose.

This point settled, let it now be remarked, that Herschel's resources enabled him to unmask many of these nebula: stars they were, and stars he forced them to own themselves. Why should any decent world wear an alias? There was nothing, you know, to be ashamed of in being an honest cluster of stars. Indeed, they seemed to be sensible of this themselves, and they now yielded to the force of Herschel's arguments so far as to show themselves in the new character of nebula spangled with stars; these are the stellar nebulæ ; quite as much as you could expect in so short a time: Rome was not built in a day: and one must have some respect to stellar feelings. It was noticed, however, that where a bright haze, and not a weak milk-and-water haze, had revealed itself to the telescope, this, arising from a case of compression, (as previously explained,) required very little increase of telescopic power to force him into a fuller confes. sion. He made a clean breast of it. But at length came a dreadful anomaly. A nebula' in the constellation Andromeda turned restive: another in Orion, I grieve to say it, still more so. I confine myself to the latter. A very low power sufficed to bring him to a slight confession, which in fact amounted to nothing; the very highest would not persuade him to show a star. 'Just one,' said some coaxing person; 'we'll be satisfied with only one.' But no: he would not. He was hardened, 'he wouldn't split.' And Herschel was thus led, after waiting as long as flesh and blood could wait, to infer two classes of nebula; one

that were stars; and another that were not stars, nor ever were meant to be stars. Yet that was premature he found at last, that, though not raised to the peerage of stars, finally they would be so they were the matter of stars; and by gradual condensation would become suns, whose atmosphere, by a similar process of condensing, would become planets, capable of brilliant literati and philosophers, in several volumes octavo. So stood the case for a long time; it was settled to the satisfaction of Europe that there were two classes of nebula, one that were worlds, one that were not, but only the pabulum of future worlds. Silence arose. A voice was heard, Let there be Lord Rosse!' and immediately his telescope walked into Orion; destroyed the supposed matter of stars; but, in return, created immeasurable worlds.

As a hint for apprehending the delicacy and difficulty of the process in sidereal astronomy, let the inexperienced reader figure to himself these separate cases of perplexity: 1st, A perplexity where the dilemma arises from the collision between magnitude and distance : is the size less, or the distance greater? 2dly, Where the dilemma arises between motions, a motion in ourselves doubtfully confounded. with a motion in some external body; or, 3dly, Where it arises between possible positions of an object: is it a real proximity that we see between two stars, or simply an apparent proximity from lying in the same visual line, though in far other depths of space? As regards the first dilemma, we may suppose two laws, A and B, absolutely in contradiction, laid down at starting: A, that all fixed stars are precisely at the

same distance; in this case every difference in the apparent magnitude will indicate a corresponding difference in the real magnitude, and will measure that difference. B, that all the fixed stars are precisely of the same magnitude; in which case, every variety in the size will indicate a corresponding difference in the distance, and will measure that difference. Nor could we imagine any exception to these inferences from A or from B, whichever of the two were assumed, unless through optical laws that might not equally affect objects under different circumstances; I mean, for instance, that might suffer a disturbance as applied under hypoth. B, to different depths in space, or under hypoth. A, to different arrangements of structure in the star. But thirdly, it is certain, that neither A nor B is the abiding law and next it becomes an object by science and by instruments to distinguish more readily and more certainly between the cases where the distance has degraded the size, and the cases where the size being really less, has caused an exaggeration of the distance: or again, where the size being really less, yet co-operating with a distance really greater, may degrade the estimate, (though travelling in a right direction,) below the truth; or again where the size being really less, yet counteracted by a distance also less, may equally disturb the truth of human measurements, and so

on.

A second large order of equivocating appearances will arise, not as to magnitude, but as to motion. If it could be a safe assumption, that the system to which our planet is attached were absolutely fixed and

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motionless, except as regards its own internal rela tions of movement, then every change outside of us, every motion that the registers of astronomy had established, would be objective and not subjective. It would be safe to pronounce at once that it was a motion in the object contemplated, not in the subject、 contemplating. Or, reversely, if it were safe to assume as a universal law, that no motion was possible in the starry heavens, then every change of relations in space, between ourselves and them, would indicate and would measure a progress, or regress, on the part of our solar system, in certain known direc tions. But now, because it is not safe to rest in either assumption, the range of possibilities for which science has to provide, is enlarged; the immediate difficulties are multiplied; but with the result (as in the former case) of reversionally expanding the powers, and consequently the facilities, lodged both in the science and in the arts ministerial to the science. Thus, in the constellation Cygnus, there is a star gradually changing its relation to our system, whose distance from ourselves (as Dr. Nichol tells us) is ascertained to be about six hundred and seventy thousand times our own distance from the sun : that is, neglecting minute accuracy, about six hundred and seventy thousand stages of one hundred million miles each. This point being known, it falls within the arts of astronomy to translate this apparent angular motion into miles; and presuming this change of relation to be not in the star, but really in ourselves, we may deduce the velocity of our course, we may enter into our log daily the rate at which our whole solar system is

running. Bessel, it seems, the eminent astronomer who died lately, computed this velocity to be such (viz., three times that of our own earth in its proper orbit) as would carry us to the star in forty-one thousand years. But, in the mean time, the astronomer is to hold in reserve some small share of his attention, some trifle of a side-glance, now and then, to the possibility of an error, after all, in the main assumption he must watch the indications, if any such should arise, that not ourselves, but the star in Cygnus, is the real party concerned, in drifting at this shocking rate, with no prospect of coming to an anchorage.8

Another class, and a frequent one, of equivocal phenomena, phenomena that are reconcilable indifferently with either of two assumptions, though less plausibly reconciled with the one than with the other, concerns the position of stars that seem connected with each other by systematic relations, and which yet may lie in very different depths of space, being brought into seeming connection only by the human eye. There have been, and there are, cases where two stars dissemble an interconnection which they really have, and other cases where they simulate an interconnection which they have not. All these cases of simulation and dissimulation torment the astronomer by multiplying his perplexities, and deepening the difficulty of escaping them. He cannot get at the truth in many cases, magnitude and distance are in collusion with each other to deceive him: motion subjective is in collusion with motion objective; duplex systems are in collusion with fraudulent stars, having