"And equally so, no doubt," returned Mr. Gubbins, "the idea which the name imports. The truth is, that in all this branch of astronomy to which the name belongs, the discoveries, for which we are originally indebted to Sir William Herschel and his sister, were lightly thought of (as is so commonly the case) during the lives of the discoverers, and are only now advancing in repute. I must therefore explain to you, both what is meant by this term nebula, or 'cloud' of stars, so far outstripping the idea of a constellation or group of stars; and to what a vast hypothesis, or general scheme, of astronomical natural history, the term essentially belongs." But, as he spoke these words, Mr. Gubbins put himself in order to deliver his knowledge with due solemnity; and all the company, at the same time, in silence, and with deep attention, looked alternately at the speaker, and at the chalk figure which he had drawn and superscribed, and to which he occasionally pointed,

I. THE NEBULE.

"The hypothesis advances," resumed Mr. Gubbins, "that the heavens are filled with stars, the whole of which are every where distributed into nebulæ or clouds; that is into masses or bodies with intervals between; and the idea of which nebulæ is to be confounded, neither with that of constellations nor that of systems; for a nebula contains many constellations, and a constellation many systems. These nebulæ, in short, are cloud or vapour-like appearances, of a brilliant whiteness, in this manner distinguished from the ground of the dark heavens; are seen with telescopes of moderate powers; are ascertained to be more distant from us than our constellations; are what, assisted

by telescopes of higher powers, the eye resolves into clouds of stars-as clouds of dust are resolvable into particles. These nebulæ are supposed to be millions in number; some near enough to display to us their individual stars, while others, at greater distances, betray, through the glasses of the best instruments yet made, only masses of unbroken light; the spaces between their systems and constellations escaping even all our most assisted powers of vision. But each nebula, it is said, must have, not only its own exclusive constellations, systems, or whole starry heaven, but its own milky way as well, exhibiting the projection of the nebula upon the body of the etherial space; and again, from each of the systems, and from each planet of each system, the appearance of the heaven of that nebula must vary; its several constellations changing their apparent forms to the view of every system, and distinguishing themselves by different degrees of lustre, both according to the position of the system in the nebula, and to its distance from the constellation. We subsist, it is argued, within the circumference of one of these nebulæ. Our sun, or fixed star, belongs to one of these nebulæ; and all the scattered or distinct stars which are visible, either to our naked eye, or through our telescopes, and make up our constellations, are luminaries of no more than our own nebula. It is behind our constellations, or beyond the limits of our nebula, and of the space surrounding it, that the foreign nebulæ are placed; and through the spaces between our stars, that we discover them. But, to convey to you some account of what these nebulæ are supposed 10 contain, I will now describe the nebula of the earth, or that cloud of stars among which is our sun, the star upon which we more immediately depend!

II. THE NEBULA OF THE EARTH.

" is now

"The nebula of the earth," continued he, taken to comprehend all and more than we see with the naked eye of the whole heaven; or, in other words, the whole portion, and even more, that we see, with the naked eye, of the whole heaven; or, that which we commonly call the whole heaven or heavens, is held to be included within the single nebula of the earth! This nebula includes every star, either commonly or only telescopically visible, but which is scattered, -separated from other stars,-or, in other words, distinguishable as a star; and within the circumference of this nebula are to be measured all those prodigious distances, the names and figures of which confound all our ideas of measure; for it is only beyond this nebula that begins the space containing other nebulæ, and those distances with respect to which we enter into no calculation! This nebula of the earth, then, contains all the fixed stars with which we are acquainted, or which we commonly so call; all the constellations to which we give names; and (minute in the estimate of things and bodies so vast and so transcendent) that particular fixed star which is our sun, with all its planets and its comets! Sir William Herschel ventured to think that he had ascertained the figure of the mundane nebula, or nebula of the earth; and also the position of our sun, or of our solar sytem, within the nebula.

III. THE GALAXY, OR MILKY WAY.

"The galaxy, or milky way," still continued Mr. Gubbins, "which, at one time, was thought only a meteoric light, and at another, a vast nebula, or bed,

or stratum of fixed stars, is now held to be the projec tion of our nebula, or of our cloud, or mass of light, in the heavens. It was through examining the milky way, that Sir William Herschel became encouraged to turn his telescope toward the nebulæ.

IV. THE FOREIGN NEBULE.

"The foreign nebulæ (for it is by this name that I venture to distinguish the other nebulæ of the heavens from our own nebula of the earth) may now be better understood. Their composition is held to resemble that of the nebula of the earth. They have their stars, their constellations, their planetary systems; but all apart from ours. We see our own portion of the heavens; the foreign nebulæ afford to their inhabitants the sight of other portions. We see none of their constellations, and much less their systems of suns and planets and comets, and they see none of our systems nor constellations. At what distances these foreign nebulæ are placed from the nebula of the earth; at what distances they are placed from each other; at what distances stand their constellations, and revolve their systems, their suns, their planets, and their comets, is only to be imagined from analogies that we possess nearer home. The nearest of the stars belonging to our nebula, to the earth our habitation, is sometimes said to be distant 32,000,000,000,000 miles; a space over which a cannon-ball, moving throughout the way with the velocity at which it leaves the cannon's mouth, could not travel in seven millions of years. Or, the distances of all (even the nearest) of the fixed stars of our nebula are considered as immeasurable; and yet all these distances, measur

able and immeasurable from the earth (which, supposing this latter to be placed in the centre of the nebula, would make the furthest of them no more than half of its diameter), are to be included within the magnitude of our single nebula! Go on, then, to imagine the universe comprising myriads of these nebulæ, separated from each other by spaces still more enormous, and possessing, within themselves, spaces of such magnitude, with their several stars or systems, and their several constellations or congregations of systems, as the comparison with our own may faintly help us to conceive; think of each of these nebulæ as of a brilliant dew-drop, or as one of those drops of water which the microscope discovers to us filled with millions of insects; think of these semblances to the microscopic insects, not as the men, or other living creatures of these nebulæ; not as their planets; not as their suns only; but as the mingled lustres of their systems, of their groups of suns and planets, and therefore only as the bodies upon which move their men, or other living creatures! Think of this (if it is possible for you to think of it; if it is possible for you to form any idea of the figure of such a spectacle); and then feel the sentiment (if the sentiment can be adequately entertained by the heart of man) of the immensity of space, of the magnitude and beauty of its forms, and of their prodigious and incalculable number-' in number numberless!' But you will scarcely believe what I am saying; you will fancy that I am giving you, not science, but romance;-listen, therfore, to a part of what Sir William Herschel has written upon the subject:

"The nebulæ,' says that distinguished astronomer, are arranged into strata, and run on to a great length;