Had our author proved all he has assumed our faith would not be lessened, nor our wonder diminished. Whether matter or spirit has been the world's architect, the astounding miracle of its creation is not the less. What does it import whether it resulted direct from the fiat of Omnipotence, or intermediately from the properties He impressed, or the law of development He prescribed? He who gave the law, who infused the energies by which Chaos was transmuted into an organized universe, remains great and inscrutable as ever.
It is time, however, that we entered upon a more detailed and closer investigation of the Vestiges of Creation. Our purpose is not hastily, and without examination, to deprecate, deny, or controvert; but patiently, and without prejudice, to inquire, to submit faithfully and intelligibly the outlines of a remarkable treatise; describe briefly its scope and bearing, the arguments by which they are supported, and the counter reasons by which they appear to be wholly or partially impugned. Our readers will thus be enabled to appreciate the merits of a controversy, the most comprehensive and interesting that for a lengthened period has occupied the attention of the scientific and intellectual world.
For greater clearness of exposition we shall endeavour to follow the order observed by the author in the division and treatment of his subjects, commencing first with the
BODIES OF SPACE.
The author opens his subject with a brief but luminous outline of the arrangement and formation of the astral and planetary systems of the heavens. He first describes the solar system, of which our earth is a member, consisting of the sun, planets, and satellites with the less intelligible orbs termed comets, and taking as the uttermost bounds of this system the orbit of Uranus, it occupies a portion of space not less than three thousand six hundred millions of miles in diameter. The mind cannot form an exact notion of so vast an expanse, but an idea of it may be obtained from the fact, that, if the swiftest racehorse ever known had began to traverse it at full speed at the time of the birth of MOSES, he would only yet have accomplished half his journey. Vast as is the solar system, it is only one of an infinity of others which may be still more extensive. Our sun is supposed to be a star belonging to a constellation of stars, each of which has its accompaniment of revolving planets; and the constellation itself with similar constellations to form revolving clusters round some mightier centre of attraction; and so on, each astral combination increasing in number, magnitude, and complexity, till the mind is utterly lost in the vain effort to grasp the limitless arrangement.
Of the stars astronomers can hardly be said to know anything with certainty. Sirius, which is the most lustrous, was long supposed to be the nearest and most within the reach of observation, but all attempts to calculate the distance of that luminary have proved futile. Of its inconceivable remoteness some notion may be formed by the fact, that the diameter of the earth's annual orbit, if viewed from it, would dwindle into an invisible point. This is what is meant by the stars not having, like the planets, a parallax; that is, the earths' orbit, as seen from them, does not subtend a measurable angle. With two other stars, however, astronomers have unexpectedly and recently been more fortunate than with Sirius, and have been able to calculate their distances from the earth. The celebrated BESSEL, and soon afterwards, the late Mr. HENDERSON, astronomer royal for Scotland, were the first to surmount the difficulty that had baffled the telescopic resources of the HERSCHELS. BESSEL detected a parallax of one-third of a second in the star 61 Cygni, and in the constellation of the Centaur HENDERSON found another star whose parallax amounted to one second. Of the million of fixed glittering points that adorn the sky, these are the only two whose distances have been calculated, and to express them, miles, leagues, or orbits seems inadequate. Light, whose speed is known to be 192,000 miles per second, would be three years in reaching our earth from the star of HENDERSON; and starting from BESSEL'S star and moving at the same rate it could only reach us in ten years. These are the nearest stars, but there are others whose distances are immeasurably greater, and whose light, though starting from them at the beginning of creation, may not have reached our globe!
The stars visible to the eye are about 3,000, but the number increases with every increase of telescopic power, and may be said to be innumerable. They are not of uniform lustre or form, but vary in figure and brightness. Some of them have a nebulous or cloudy appearance; and there are entire clusters with this dusky aspect, mostly pervaded, however, with luminous points of more brilliant hue. In the outer fields of astral space Sir WILLIAM HERSCHEL observed a multitude of nebulæ, one or two of which may be seen by the naked eye. All of them, when seen by instruments of low power, look like masses of luminous vapour; but some of them had brighter spots, suggesting to Sir WILLIAM the idea of a condensation of the nebulous matter round one or more centres. But when these luminous masses are examined by more powerful instruments many of them lose their cloudy form, and are resolved into shining points, "like spangles of diamond dust." It is in this way several nebulæ have yielded to the gigantic reflector of Lord ROSSE, and others with still greater optical resources may follow. This brings us to the first questionable and controversial portion of the Vestiges; namely,—the
NEBULAR HYPOTHESIS.
It is among the gaseous bodies just described, in the outer boundary of Nature, which neither telescope nor geometry can well reach, that speculation has laid its venue, and commenced its aerial castles. LAPLACE was the first to suggest the nebular hypothesis, which he did with great diffidence, not as a theory proved, or hardly likely, but as a mathematical possibility or illustration. His range of creation, moreover, was not so vast as that of our author, which assumes to compass the entire universe, but was limited to the evolution of the solar system. The mode in which this might be evolved, LAPLACE thus explains:—
He conjectures that in the original condition of the solar system the sun revolved upon his axis, surrounded by an atmosphere which, in virtue of an excessive heat, extended far beyond the orbits of all the planets, the planets as yet having no existence. The heat gradually diminished, and as the solar atmosphere contracted by cooling, the rapidity of its rotation increased by the laws of rotatory motion, and an exterior zone of vapour was detached from the rest, the central attraction being no longer able to overcome the increased centrifugal force. The zone of vapour might in some cases retain its form, as we still see in Saturn's ring; but more usually the ring of vapour would break into several masses, and these would generally coalesce into one mass, which would revolve about the sun. Such portions of the solar atmosphere abandoned successively at different distances, would form planets in the state of vapour. These masses of vapour, it appears from mechanical laws, would have each its rotatory motion, and as the cooling of the vapour still went on, would each produce a planet that might have satellites and rings formed from the planet, in the same manner as the planets were formed from the atmosphere of the sun.