PART V. GENERAL VIEWS RESPECTING THE SOLAR SYSTEM.

From the length to which these inquiries with regard to the nature and motions of Comets have extended, arrived at this point, I should be inclined to bring this Essay to a conclusion. But as, in an inquiry like the present, it would be improper to omit any consideration calculated to throw light either upon the extent or on the formation of the planetary system, of which the Comets form so important a part, I cannot forbear to notice the information which these bodies afford on this most interesting branch of Astronomy.

I. Buffon was the first who attempted, in a philosophical manner, to throw some light upon the origin of the Planets. Struck with the remarkable fact, that all of them move round the sun in one direction, and nearly in the same plane, he imagined that originally they were fragments, struck off from the body of the sun whilst in a fluid state, by the concussion of Comets; and that, by the mutual attraction of their particles, and the rotatory motion likewise given to them at the time of their detachment, they have gradually acquired the spherical forms which each is found now to possess. This theory, it has always been allowed, has the merit of at least being ingenious, and serves sufficiently well to explain the particular phenomenon which exclusively engrossed the attention of its author. But there are many other facts, equally characteristic of the planetary movements, totally irreconcileable with such an hypothesis. For, if these fragments set out upon their respective courses from the same point, it is demonstrable by the laws of central forces, that if, after one revolution, they did not relapse into the body of the sun, from which they were driven, their orbits ought at least to be extremely eccentric, and intersect at no great distances either from the sun or from one another. But our knowledge of the actual arrangement of the system gives results very different from these conclusions. The simple fact, that the orbits of the planets do not vary materially from circles of which the sun is the common centre, is sufficient at once to overturn Buffon’s theory. How, moreover, are we to explain the remarkable conformity of direction, by which all the satellites are characterized in their motion round their primaries,—a direction the same as that of the planets in their own course?—and how the equally remarkable concurrence of direction, in the diurnal rotation of all the bodies of our system, with that of the progressive movement in their orbits‍‍139?

These are questions which have exercised the genius and researches of astronomers more eminent and profound than Buffon; and many are the solutions which have been attempted. But whatever be the theory proposed, it is evident that it ought to embrace the explanation of all the above mentioned phenomena; and the causes will then most probably stand revealed, which have operated in the formation of the whole planetary system.

This accordingly was the safe ground on which La Place proceeded, when he applied the force of his profound and comprehensive genius to this difficult subject; and, as the theory which he advanced leaves out none of the conditions of the problem, it has been regarded by astronomers, if not developing the precise manner in which the Planets and Comets were actually generated, as at least shewing the general principles which characterize the formation of the system. La Place supposes, that the planets have been produced out of an extensive atmosphere or nebulous medium, which originally existed about the sun. The mass of the sun, having by some means (probably the decrease of its temperature) contracted in bulk, the velocity of its rotation thereby became augmented, and a portion of its atmosphere detached by reason of the centrifugal force. Thus a zone would be produced, which, though separated from the sun, would still continue to circulate round it in the same direction; and as the process of refrigeration and increased velocity simultaneously advanced, other zones would in like manner be successively formed, having the sun as the centre of their motion, and all situated in nearly the same plane. The nebulous particles composing these zones would then gradually acquire a tendency to coalesce with one another, and at length a spheroidal mass would be the result of the general attraction. In this manner, La Place ingeniously accounts for the origin of the planets, whose revolution is in the same direction with the sun’s rotation about its axis, and all of which move nearly in the plane of the ecliptic. The theory likewise accounts for the remarkable circumstance of their diurnal rotation being in the same direction as their progress in their orbits: because since in each of the zones above mentioned, the convex side must have possessed a greater velocity than the concave, whenever these zones had coalesced into the globular shape, a rotation would be communicated to all, in the same direction as their movement round the sun. If now we follow up the changes which would subsequently take place in those liquid or nebulous masses of which the planets originally consisted, it is evident, that, after some time, there would gradually be formed a nucleus in the centre of each. This nucleus would become surrounded with an atmosphere of the more attenuated matter, and in miniature, would exactly represent the sun, as above described, with its extensive nebulous medium round it. The gradual condensation of the particles must, in this case also, as the atmosphere contracted in size and increase in velocity, have been attended with similar phenomena; and thus solid rings, or Satellites, would at length be produced, coinciding in all the circumstances of their movements with the Planets themselves.

Such is the theory of La Place, respecting the origin of the planetary system, and which most satisfactorily accounts for all its observed peculiarities. But the Comets, on account of the striking peculiarities of their movements, could not possibly be reconciled to this hypothesis. The circumstance of their moving in every direction indiscriminately, sometimes nearly at right angles to the ecliptic‍‍140, sometimes in a manner quite opposite to the course of the planets, proved, that they could not possibly have had their origin, in common with them, in a solar atmosphere. The eccentricity of their orbits indicated that they come from, and probably originate in, a quarter of the heavens far beyond the limits of the solar atmosphere, or planetary spheres; while their highly attenuated nature, as shewn by various circumstances already noticed, rendered it probable that they must be formed by the local condensation of some medium diffused through celestial space. “Dans notre hypothèse,” says La Place, “les comètes sont étrangères au systême planétaire. En les considérant, ainsi que nous l’avons fait, comme de petites nébuleuses errantes de systèmes en systèmes solaires, et formées par la condensation de la matiere nébuleuse répandue avec tant de profusion dans l’univers; on voit que lorqu’elles parviennent dans la partie de l’espace où l’attraction du soleil est prédominante, il les force à décrire des orbes elliptiques ou hyperboliques‍‍141.” This idea respecting the nature and constitution of Comets, coincides, as we see, with the opinion of Herschel, derived from other considerations already mentioned; and it certainly accounts as satisfactorily for the striking peculiarities of cometary movements, as the other part of the theory does for the motion and constitution of the planets. That the physical cause, which has restricted the course of the planets to one direction, and the inclinations of their orbits to a narrow zone in the heavens, cannot have operated in the same manner upon Comets, is farther incontestibly proved by the fact, that, out of all the Comets, whose elements are known up to the year 1826, there are sixty-eight which have moved from west to east, and sixty-four which have moved from east to west; and that, moreover, if we calculate the average amount of the inclinations of their orbits, including both direct and retrograde Comets, the result will be found to be as nearly as possible 90°. These two curious coincidences, prove, first, that the causes to which the movements, as well as formation, of the Comets are to be ascribed, must be essentially different from those which have operated in the planetary arrangement; and, secondly, that a fortuitous condensation of different portions of the etherial medium, to which, consistently with the opinions of Herschel and La Place, we would refer the production of Comets, is a theory supported in the most striking manner by observation.

II. But, though the phenomena exhibited respectively by the Planets and Comets, when thus separately considered, agree well enough with the two hypotheses of La Place, concerning the origin and formation of both, this agreement is not sufficient of itself to establish the truth of these hypotheses. It is to be remembered, that they form together one theory, applicable to the whole solar system, of which the planets and comets are only the constituent members. These two hypotheses, therefore, have an essential and intimate connection with each other; and any discrepancy between them must render the theory objectionable, so long as the discrepancy remains unremoved. Now, it will be observed, that, in La Place’s hypothesis with respect to the origin of Comets, it follows, that the orbits of all of these bodies must extend, towards their aphelia, considerably beyond the limits of the planetary spheres. But though this circumstance may be predicated of Comets in general, recent observation has shewn, that it does not always hold true. Encke’s Comet, for instance, in its course through the heavens, never passes the orbit of Jupiter; and the Comet of 1826, discovered by Gambart, and shewn by him to have been observed in 1772 and 1805, does not, at its greatest distance from the sun, go much beyond the orbit of the same planet. These, therefore, are striking facts, which I venture to state as appearing to me quite inconsistent with La Place’s theory. The theory, however, accounts so satisfactorily for all the general phenomena, of both the planetary and cometary movements separately considered, and is so plausible from its very simplicity, that à priori we are disposed to consider the objection as one which, though grounded on indisputable facts, it may still be possible to remove.

Nor does it seem very difficult to accomplish this important object, and even to derive out of the apparent discrepancy, an additional argument in favour of La Place’s theory. For, if we reflect upon the extreme liability to which Comets are exposed, on account of their highly attenuated nature, to have their movements affected by reason not only of planetary attractions, but likewise of the resistance of the ethereal medium, we obtain a clew by which the anomaly may be at once explained. Gambart’s Comet, for example, is shown by him to have been very considerably affected by planetary attractions; and, with regard to Encke’s Comet, some investigations recently made respecting its movements, during a series of revolutions, indicate a gradual diminution of the greater axis of its orbit; a circumstance which we shall afterwards show (when we come to mention these investigations more particularly) can be attributed only to the resistance of the ethereal medium. It is therefore extremely probable, nay, almost demonstrated, that, after a great multitude of revolutions, those two Comets above mentioned, which did not perhaps go very far originally beyond the limits of the planetary system, have either, from the resistance of the ethereal medium, or the effect of planetary attractions, or from both causes combined, sustained such alterations in their course, as to have been at length brought within the orbits of the planets;—alterations which may still be slowly continuing, and will in process of time diminish yet farther the eccentricity of their paths. It is by no means impossible, that the orbits of these two Comets have experienced alterations similar to those that happened to the well-known Comet of 1770, owing to which, during a period of twelve years, it was prevented from following its accustomed course beyond all the planets, and constrained to move in a new orbit, never extending much beyond Jupiter: at the end of this period of twelve years, its orbit was altered again, by a second approach to Jupiter; and, in its present movements, it never goes beyond the orbit of Uranus; so that it affords, in addition to the Comet of Encke and Gambart, a third instance of the orbit of a Comet lying wholly within the limits of the planetary system. If it were possible to show, by actual calculation, in the same manner as has been done with regard to the Comet of 1770, that the Comets of Encke and Gambart on account, whether of planetary attractions, or the continued resistance of the ethereal medium, have also been deflected from their original paths, into the paths which they now follow, arguments of irresistible force would be gained in support of La Place’s theory. But, even in the absence of direct evidence respecting these two Comets, and resting solely on the remarkable instance of the Comet of 1770, the probabilities are so numerous for the opinion, that all those Comets whose orbits do not extend beyond the confines of the planetary system, have sustained some alteration in their course by disturbing causes, as to convert the above apparent anomaly, if not into a decisive argument, into at least a presumption of the strongest nature, in favour of La Place’s theory.

III. Not satisfied with having investigated the primitive causes which have operated in producing the planetary as well as the cometary bodies, astronomers have sought to determine, and without even having recourse to observation, the actual number of planets belonging to our System. Olbers attempted to determine this point by the movements of his own Comet and those of Halley’s. The remarkable inference which he deduced from his investigations was, that there are no more planets than what have been already discovered. But this result, though it seems to have been received by astronomers on the Continent‍‍142, as the correct and decisive answer to the above important inquiry, is completely refuted by a reference to the movements of other Comets; and, in fact, though with all deference to the authority of Olbers, deserves to be regarded rather as the fruit of a wild and overweaning philosophy, than as a sound and deliberate deduction of science. The grounds on which Olbers proceeded in this inquiry are these: Since all the known planets are found in their respective distances from the sun, to observe a common law of progression, he assumed at the outset, that, if any planet does exist beyond Uranus still undiscovered, it must be at a certain distance, which, as depending on the same law, may be at once determined. It follows, therefore, from this, that if there be a planet revolving beyond Uranus, it will be situated 38.8 times farther from the sun than the earth‍‍143. But, proceeding on La Place’s theory, which, as we have just seen, implies that the aphelia of all Comets lie considerably beyond the sphere of the planets, Olbers inferred, that if any Comet is known, whose orbit does not extend so far as the point at which this additional planet would revolve, then this single fact must at once refute the possibility that any such planet can exist. Now, Halley’s Comet, even at its greatest distance from the sun, as well as the Comet which Olbers himself had recently discovered, never removes farther from the sun than 36 times the earth’s distance; and he therefore thought himself entitled at once to conclude, that no planet can revolve beyond Uranus, and therefore that all the planets which belong to our system are already known. But, if the astonishing advancement which astronomy has effected within the few last years‍‍144, were not sufficient to cast strong doubts on the correctness of this bold assertion, the recent discovery of two Comets, the greater axes of whose orbits do not exceed one-half the distance of Uranus from the sun, completely demonstrates its absurdity. For, upon the same grounds, and with just as much semblance of truth, it might be maintained, from a consideration of the Comet of Encke, that no planet exists in a quarter of the heavens where the three largest bodies of the system, Jupiter, Saturn, and Uranus, do actually revolve. So far, indeed, from its being probable, that no other planets now remain to be discovered, there are various reasons which lead us to believe that many still exist beyond the known limits of the system; but whose prodigious distance and highly attenuated nature, place them perhaps altogether beyond the reach of human discernment. If any such bodies there are belonging to our system, a Comet will be the most likely means of giving us assurance or information of their existence, by means of the perturbations which it may sustain, on coming within the sphere of their attraction. Astronomers will thus be enabled, even though these planets should remain for ever invisible from the earth, not only to ascertain the peculiarities of their extensive orbits, but even to obtain some intelligence concerning their physical constitution.

IV. But though Astronomers may thus justly look forward to the most wonderful discoveries respecting the extent and constitution of the planetary system, which, at a future period, will be effected by the aid of Comets, these bodies have already added one very curious and important fact to our knowledge of the universe. From Newton down to La Place, the most celebrated philosophers have concurred in thinking, that an ethereal medium, or some material substance of a highly attenuated nature, must be diffused through the celestial regions. But they were unable to obtain any conclusive or positive evidence, in support of this opinion; and though it was hardly conceivable that the spaces in which the heavenly bodies revolve, should be absolutely empty, their reasoning on the subject was rather of a negative description, and not very dissimilar to the ancient doctrine, of Nature’s abhorrence of a vacuum. It was necessary that the fact should be established by the positive and satisfactory evidence of observation, to entitle it to rank as one of the most brilliant discoveries of astronomical science. Clairault was the first who attempted to estimate the influence which such a resisting medium was calculated to produce upon the motions of the heavenly bodies; and, in an appendix to his celebrated work, which announced the return of Halley’s Comet within so short a time of its actual arrival, he endeavoured to calculate the effect which this resistance would have upon its motions. It is obvious that the principal effect will be, to weaken the projectile and centrifugal force which the moving body originally possesses, and thus cause the sun’s attraction to exert a greater power in controlling its movements; so that, in general, the resistance of such a medium will continually be shortening the greater axis, and thus cause a diminution of the eccentricity, and a corresponding augmentation in the mean motion; while the nodes and inclination, which alone affect the plane of the orbit, will remain wholly exempt from alteration. Proceeding on these data, Clairault found, with respect to Halley’s Comet, that the change produced on its mean distance from the sun, would be nearly three times what a planet moving in a circular orbit would sustain, having the same period as the comet (or 75 years): and from this he inferred, that, in the course of each revolution, there would be an acceleration of 7 1/2 minutes in the periodic time. But Halley’s Comet, on account of the eccentricity and great extent of its orbit, is exposed to too many perturbations from planetary attractions, to afford any very certain evidence of such an effect having been actually produced: nor was it likely, when we consider the infancy of astronomical science in 1759, that so small an alteration could have been easily detected.

Encke’s Comet, whose period is much shorter, and has now been observed on its return to the perihelion six times, is better calculated for the prosecution of this delicate inquiry. In determining the elements of this Comet for every succeeding return, Encke has found that a small variation constantly prevails between his calculations and the result of observation, which the strictest regard to planetary perturbations is not sufficient to correct. Now, this variation corresponds exactly with the alterations, such as we have already described, which a resisting medium would produce upon the comet’s movements. The eccentricity of its orbit is found to be slowly but constantly, diminishing, its mean motion augmenting, and the period of its revolution becoming shorter; whilst the inclination and place of the nodes remain nearly uniform: and, in order to account for these changes, “the most natural of the causes which we can suppose,” says M. Encke, “is the resistance of an ether diffused in space.” Encke, proceeding on the supposition that such a medium does exist, computed the effects of its resistance upon the elements of the comet, as they should have been indicated by observation in 1795, 1805, and 1819; and in this manner he was able to reduce the errors for these three revolutions to less than half the amount. If we be not yet entitled, therefore, to conclude that some resisting ethereal medium has been fully proved, by means of the Comet of Encke, it will be admitted, that at least we have now the highest probability of its existence. But it is remarked by Olbers,‍‍145 that, “with respect to this comet, such a resistance seems to be almost demonstrable à priori; for it moves during a considerable portion of its period, in that part of the open space of the system, in which the visible substance of the zodiacal light, or solar atmosphere, is found. It is this same comet through the middle of which, Herschel, on the 9th November 1795, saw a small double star of the 12th or 13th magnitude, with very little diminution of its brightness. This fact seems to demonstrate, that the density of the comet bears some finite proportion to that of the zodiacal light, and that the substance causing this light may afford a sensible resistance to the motion of the comet. If, then, all the rest of the space surrounding us were to be considered as perfectly void, and free from resistance, which I do not believe, still the resistance of the zodiacal light, which certainly does exist, is sufficient to explain the phenomena of a diminution in the periodic time, and in the eccentricity of the orbit.”

It has, however, been objected to the supposition of an ethereal medium, that its existence should also have been made apparent by its influence on the movements of the planetary bodies, in like manner as upon those of comets. But it must be recollected, that this resistance is capable of affecting the planets in an infinitely less degree than the comets, which, possessing perhaps a volume of 1000 times as great, have a mass 1000 times smaller than the former; so that, though the resistance of the ethereal medium may affect the movements of the planets in too slight a degree to be detected, its effect upon comets, as it is so greatly superior, will be much more easily observed.‍‍146 It has also been suggested that the ethereal medium most probably possesses a motion of its own round the sun, in conformity with the solar atmosphere, out of which (according to La Place’s theory) the planets have been formed; so that its resistance to these bodies, moving in the same direction with itself, can, for this additional reason, be very little appreciable; whilst upon the comets, which in their movements have nothing at all in common with the planets, the effects of its resistance will entirely depend on the direction of the comet.

Nor ought we to forget in this place the farther proofs of the existence of this ethereal medium, which the form and direction of a comet’s tail so readily suggest. But as these phenomena have been already detailed in a former part of the Essay, and their production fully explained on the supposition of resistance arising from this cause, we need here only refer to what has been there stated.

V. Were not the period now long since past, in the history of philosophy, when the theory of universal gravitation, that principle which has served as the talisman of modern astronomy, required to be established on the basis of extensive observation, the movements of comets would afford the most effectual means. Wandering away into distant and invisible regions of space, we can follow them with this principle as our guide, and even anticipate the period when, after the lapse of centuries or of ages, they shall again return to the sun: and even when they have been deflected from their regular track, and suffered in their orbits the most extensive changes, the same principle at once suggests the cause, and enables us to compute their amount. Mankind have hitherto been accustomed to look upon the Solar System as if it were circumscribed by the orbit of the farthest planet;—but the paths of comets, which are determined by the same law that governs the movements of the planetary bodies, indicate an extent of power residing in the sun, of which astronomers as yet can form a very inadequate conception. Some comets, indeed, whose orbits have been computed, already shew that the solar attraction exerts its power in regions of space, above 700 times the Earth’s distance from the sun.‍‍147 But as our knowledge of these interesting bodies advances, astronomers in a future age of the world will be enabled to form more probable conjectures concerning the magnitude of the sphere, within which the sun’s attraction is confined. For it is evident, that some such limit must exist; and every orbit of a comet, found more distant than another, will facilitate a gradual approximation towards the discovery of this limit.‍‍148

VI. Such are a few of the leading views, with regard to the Solar System, which Comets, from the peculiarities of their movements and physical nature, serve to develope. But, besides these inquiries, which form of themselves so interesting a part of Physical Astronomy, there are other reflections which cannot be overlooked at the conclusion of an Essay like the present. When we contemplate the former opinions of mankind upon those general views respecting the universe, to which we have just been adverting, there is no circumstance in the history of the species so pregnant with moral instruction, as to witness how effectually Astronomy has removed the prejudices of preceding ages. The time once was, when the heavenly bodies were looked upon only as subservient to the affairs of this Earth. The stars were believed to be the abode of heroes and lawgivers, who, after having benefitted this world by their labours, were there translated for the enjoyment of eternal bliss. The benignant or baneful influence of the planets was conceived to determine the destinies of men at their birth, and to operate on their fortunes till the latest moment of life; while many an enterprise, on whose issue the fate of Empires depended, has failed or succeeded by the unlooked-for occurrence of an eclipse. The Comets, as we have had frequent occasion to notice in the course of this Essay, were beheld with feelings of peculiar terror. The heralds of war,—the precursors of plague and famine,—the abode of the damned,—ministers of the vengeance of heaven;—these were among the more important offices assigned to them. Every event and circumstance was viewed, only as it appeared to affect the concerns of mortals. The Earth was made the centre of the boundless universe; it was conceived to be endowed with a soul, emanating from the essence of the Deity; and the beings, to whom it had been given as a dwelling, were deemed to participate in the same celestial attributes.

Such doctrines as these, so revolting to reason and philosophy, evidently sprung from those haughty ideas respecting the nature and destinies of man, which were the offspring of his pride and selfishness. Wholly absorbed in the enjoyment of low desires, or engrossed with the pursuit of their puny interests, men carried not their view beyond the narrow spot, of which they found or fancied themselves the undoubted lords. Every reflection was banished which could offend the bold and arrogant pretensions of this creature of clay, and lower his lofty conception of the place which he held in the scale of existence. In his opinion, the welfare of the species occupied a large space in the vision of Providence,—formed an important object in the vast arrangements of Nature; and no phenomenon could take place, whether on the surface of the earth, or even in the wide expanse of the heavens, which was not believed to have a peculiar reference to the concerns of this nether world.

To loosen the hold of such prejudices on the mind, and promote juster conceptions of the various parts of creation, it was necessary that men should be accustomed to more extended and comprehensive views. Happily we may say, that, in the present enlightened period of the world, those prejudices exist no longer; and it is chiefly by the discoveries of Astronomy that the mighty change has been effected. No longer now do we find the character and fortune of individuals imputed to the Martial, Jovial, Saturnine, or other planetary influences, which happened to predominate at their natal hour. No longer do Comets “from their horrid hair shake pestilence and war;” or occasion any of the other thousand calamities which, by their dismal aspect, they were conceived to portend. Comets and Planets have long since been referred to their true places in the system: the movements of both, as well as their physical agency on one another, have become a matter of easy calculation; and those of them, in particular, which were formerly the objects of so much superstitious dread, have been stripped of all their terrors, and converted into objects of science. The globe which he inhabits, and for which, as the scene of his existence, man has ever been solicitous to claim an important situation in the universe, is found to be only one and one of the least among many worlds like itself; and even besides the Planets and Satellites, of which our System was once believed to be solely composed, Astronomy has shewn that there exist a multitude of other orbs, viz. the Comets, which likewise revolve about the sun, each forming a world by itself, fulfilling its own separate functions in the great economy of Nature.

When we thus carry our view over the vast and varied field of worlds and of systems which Astronomy unfolds, our own terrestrial habitation sinks into insignificance. How little, how insignificant, compared with the same standard, is Man! If the globe, on which he measures out the short thread of his existence, is no more than a mere speck in the immensity of the Universe, what simile can represent, or what imagination apprehend, the nothingness of the beings to whom that speck is a world! Have we not every reason, which the nature of the case admits, for supposing that the Comets are peopled with living creatures as well as the Earth?—and if so, what myriads of them, exceeding the possibility of computation, must there be diffused through every part of the universe! Moreover, from the peculiar situation which they occupy in our System, it is not unnatural to think that those beings are of an order far superior to the human species; if we only reflect upon the immense facilities they possess of acquiring that intimate and extended knowledge of Nature, on which their rank in the scale of intelligence must be admitted mainly to depend.

With how little reason, then, has man been accustomed to look upon the puny ball, on which his lot is cast, as the most distinguished among the multitude of worlds scattered over the expanse of the heavens! With how little right, does he presume to arrogate to himself the highest place in the scale of animated being, when the whole universe teems with life and with intelligence! The human species forms no more than a link in that chain of existence, which, without any visible termination, stretches over the boundless field of creation. Where, then, we may ask, are the proofs which philosophy can advance of the vaunted and exalted nature of Man? Formed of the like frail materials as the vilest worm which he treads on, Man for a while may exert his pigmy strength on the surface of his molehill, sacrificing the lives of millions to his merciless ambition, and subverting the order of all things within the narrow spot of his abode: but can he, by the might of his arm, avert the fatal stroke which levels him in the dust, or retard for one instant the globe, which hurries him onward through space? A few brief years, spent in the pursuit of vanities, make up the whole sum of the life of man; and then, like the plants, or the beasts of the field, he sinks down into his native earth. Thus it is that one generation makes way for another, in rapid and melancholy succession. The same characters are for ever flitting along the stage of the world: all are silently carried away by the stream of Time, and launched at length into the gulf of Oblivion.

And yet, if we compare the insignificance of Man, as thus forcibly evinced by the immensity of the Universe, with the powers of mind he can exert, and the knowledge he has acquired, the reflection serves to alleviate the impressions which these solemn, but philosophical, views of human nature have a tendency to excite. When we contemplate the astonishing discoveries which this same pitiful creature Man has effected, concerning the movements and origin of the heavenly bodies, as well as the extent and constitution of the planetary system, we are lost in wonder and admiration. Darting his feeble vision from the surface of his own globe, by means of the telescope he directs his inquiring eye to the farthest limits of creation, he examines other worlds moving in their various courses, at almost immeasurable distances from his own: he is able to discover the peculiarities of their orbits, and even to obtain intelligence respecting their physical structure. Those other bodies, the Comets, which withdraw themselves far beyond the reach of perception, are not for that reason altogether lost to him. With the penetrating eye of science he can follow them through their mazy and eccentric courses, and exactly anticipate the period, when, after ages have elapsed, they will again be witnessed by posterity returning to the centre of the system. These bodies may thus be regarded as the couriers of man, bringing information of various facts from the unexplored and unknown regions of space, which his own scanty and imperfect faculties could never directly obtain. By aid of the vast stores of knowledge which man by such means has acquired, he is able to predict the great phenomena of the heavens long before their actual occurrence; he delineates the tracks which the countless orbs rolling through space will pursue for thousands of years; and can predict those terrible catastrophes arising from the crush of worlds, which will not only cause the annihilation of his species, but disorganise or alter the whole fabric of the system. Thus winging his adventurous way upon the resources of science, and rising to an acquaintance with the designs of Providence itself concerning the destinies of the world, Man nobly vindicates the superiority of his lofty character! We behold the vigorous efforts of his soul, that vital principle in which his strength resides, struggling to free itself from this mortal coil,—elevating him far above his material nature; and even prolonging his existence to the remotest limits of time, by opening to his view a prospect of the future, as available and certain, as his experience of the past.