The Southern Literary Messenger, Volume I., 1834-35

Hints to Students of Geology.

No. II.

BY PETER A. BROWNE, ESQ.

The most effectual way to guard against the dangerous tendency of theories is to collect and lay open to examination at one view some of the most celebrated of them, with which mankind have from time to time been furnished. Several of these will be found to be so obscure that astonishment is excited that they were ever dignified with the name of philosophy; others are so entirely inconsistent and at the same time have such equal claims to plausibility that they mutually confute each other; a few are so intimately connected with the truths that the study of geology and astronomy have displayed that it is difficult to escape the hazardous abyss into which they would lead—but the greater part are the effusions of fancy, and resemble more the emanations of a feverish or disordered brain than the cool dictates of reason and common sense. It is confidently believed that the student who will attentively read them all, will be very slow to adopt any one of the number.

The most ancient Indian and Egyptian philosophers agreed in rightly ascribing the creation of the world to an OMNIPOTENT and INFINITE BEING, and it is a curious fact that they represented him as having repeatedly destroyed and reproduced the world and its inhabitants. In "the Institutes of Menu," the sacred volume of the Hindoos, which were written eight hundred and eighty-eight years B.C., are the following verses:

"The Being whose powers are incomprehensible, having created me, (Menu,) and this universe, again became absorbed in the Supreme Spirit, changing the time of energy for the hour of repose."

"When this power awakes, then has this world its full expansion; but when he slumbers with a tranquil spirit, then the whole system fades away."

It is perfectly ascertained that the Greeks borrowed this idea of a former successive destruction and renovation of this world from the Egyptians. Plutarch tells us that it was the theme of one of the hymns of Orpheus; and it is well known that Orpheus, although a Greek poet, gained all his knowledge of astronomy, divinity, music and poetry in Egypt.

This most ancient Pagan theologist believed that all things were created by a Being whom he represents as invisible and incomprehensible, and to whom he has given the appellation of THE COUNSELLOR of LIGHT and SOURCE of LIFE; but he has degraded this sublime idea of the Almighty by supposing that from an egg, the progeny of chance, all mankind have been produced.

The philosopher Leucippus, who was also a Grecian, taught that "the universe was infinite; that it was in part a plenum and in part a vacuum—that the plenum contained innumerable corpuscles or atoms of various figures, which, falling into the vacuum, struck against each other; and hence arose a variety of curvilinear motions, which continued till at length atoms of similar forms met together, and bodies were produced. The primary atoms being specifically of equal weight, and not being able, on account of their multitude, to move in circles, the smaller rose to the exterior parts of the vacuum, whilst the larger (entangling themselves,) formed a spherical shell, which revolved about its centre and which included within it all kinds of bodies. This central mass was gradually increased by a perpetual accession of particles from the surrounding shell, till at last (says Leucippus) the EARTH was formed. In the mean time the spherical shell was continually supplied with new bodies, which, in its revolution, it gathered from without. Of the particles thus collected in the spherical shell, some in their combination formed humid masses, which, by their circular motion, gradually became dry and were at length ignited and became STARS. The SUN was formed in the same manner in the exterior surface of the shell; and the moon in its interior surface. In this manner the universe was formed."—Such a jargon of learned nonsense requires no comment; yet Leucippus had for a time the reputation of possessing superior wisdom!

Epicurus adopted the idea of Leucippus as to the atoms, and imagined that they moved obliquely, and Democritus bestowed on them animation. Gassendi contended for atoms and a void, and Descartes asserted a plenum and a subtle matter, which revolving in vortices was under the direction of an intelligent being.

Hippasus and Heraclitus maintained that the being who was the author of all things was fire.

Many of the ancient philosophers believed this world to be eternal—among these may perhaps be ranked Pythagoras, Aristotle, Socrates and Plato.

Zeno advocated with great zeal the theory of "two principles," spirit and matter, one active and the other passive.

Mahomet maintained that the world was created in two days, and the mountains were afterwards placed upon it; and that during these and two additional days the inhabitants were formed; and in two more the seven heavens were created.

The waters of the deluge are ridiculously represented by him as being poured out of an oven. The Alcoran says that all men were drowned except Noah and his family; and that at an appointed time God said, "O earth swallow up the waters!" "and thou, O heaven, withhold thy rain!" and immediately the waters abated. Is it not surprising that so many thousands should have adopted this theory.

Mr. Thomas Burnet was a man of genius and taste, a learned divine and a philosopher; but he suffered his imagination to take the lead of his judgment. He was the friend and object of admiration of Addison. His work is entitled, "The sacred theory of the earth, containing an account of the origin of the earth and of all the general changes which it hath already undergone or is to undergo till the consummation of all things." He taught that originally the earth was a fluid mass, composed of various materials; that of these the heaviest descended to the centre, and formed a hard and solid body—that the waters took their station round this body—and that all lighter fluids rose above the water, forming first a strata of oily matter and next a strata of air—that the air was then impure, containing great quantities of earthy particles, which gradually subsided and composed a crust of earth and oil—that this crust was the first habitable part of the earth and abode of man and other animals—that the surface was uniform, no mountains nor seas nor other inequalities were to be seen—that in this state it remained about sixteen centuries; by which time the heat of the sun gradually drying the crust, produced cracks or fissures, which gradually penetrating deeper and deeper, finally perforated the entire crust—that in an instant the whole split in pieces and fell into the great abyss of water. This (says Burnet) was the UNIVERSAL DELUGE!—That with these masses of earth were carried vast quantities of air, and the masses dashing violently against each other, accumulated and divided so irregularly, that great cavities filled with air were left between them—that the waters gradually opened passages into these cavities. In proportion as they were filled with water, the surface of the earth began to discover itself in the most elevated places, till at last the waters appeared no where but in those extensive valleys which now contain the ocean—that islands and sea rocks are small fragments, and continents are large masses of this ancient crust.

His theory was attacked and pretty roughly handled by his cotemporaries Erasmus Warren, John Keill and McFlamstead, the astronomer royal.

How Burnet could imagine that man and other land animals could have inhabited an earth which had a plane surface, it is difficult to conceive. If these animals resembled those that at present inhabit this planet, they could not have subsisted without water; and if this element was supplied by rain, and the earth had no inequalities of surface, the whole earth must have been covered by a sea or at least been a swamp. It was perhaps this reflection that generated the idea of Demailet, that man was originally a fish.

Mr. Robinson was a respectable clergyman of the English established church. In 1694 he wrote what he calls an anatomical description of the earth. He contends that matter at first consisted of innumerable particles of divers figures and different qualities; these he obliges to move about in a confused manner until the world was finally created, by the infusion of a vital spirit. He is of opinion that the earth is a great animal; that it has a skin, flesh, blood, &c. He lays it down as incontrovertible, that the centre contains a vast cavity of a multangular figure, containing crude and indigested matter, endued with contrary qualities, and causing much strife and contention. When the airy particles prevail, they cause hurricanes; when the fiery ones are uppermost, earthquakes and volcanoes are the result. The mountain chains he takes to be real ribs, and finally he seriously tells us, that this vast animal is subject to fevers, agues, and other distempers. Yet Robinson had his day, and all his readers did not appear to consider him a lunatic.

Mr. John Woodward was a classical scholar and an eminent physician. He was also a man of much observation; but he was infected with the disease of theory-making.

He agreed in part with Burnet, but refined upon him.

He contended that the waters of the ocean were aided by a supply from the central parts of the earth in effecting the general deluge. He also believed that the whole fabric was dissolved instead of the crust, as taught by Burnet. He said, that in order to assist in this general dissolution, the power of attraction, of cohesion, was suddenly suspended. Every thing being thus dissolved and jumbled in one common mass, a precipitation took place according to the laws of gravitation. Locke pronounced a panegyric upon this theory!

Mr. William Whiston, a celebrated astronomer and learned divine, also gave loose to his fancy in an extraordinary manner.

He was of opinion that the ancient chaos from which this earth originated, was the atmosphere of a comet; that the detail given by Moses is not of the creation of the world, but of its passage from the state of a comet to that of a planet, so as to make it habitable.

In the beginning, (says Mr. Whiston,) "God created the universe," but the earth was then an uninhabitable comet, surrounded by darkness; and hence, he says, we are told that, "darkness covered the face of the deep;" that it was composed of heterogeneous materials, having its centre occupied with a globular hot nucleus of about two thousand leagues in diameter, round which was an extensive mass of thick fluid; that this fluid contained few solid particles, and still less of water or air; that on the first day of the creation, the eccentric orbit of the comet was exchanged for an ellipsis nearly circular, and every thing instantly assumed its proper place. The different materials arranged themselves according to the laws of gravity, and the annual motion of the earth then began. That the centre of the earth is a solid body, still retaining the heat of the former comet; that round this is a heavy fluid and a body of water in concentric circles, upon the latter of which the earth is founded; that after the atmosphere of the earth had been thus freed from the earthy particles of that of the comet, a pure air remained, through which the rays of the sun instantly penetrated, when God said "let there be light." He ascribes to the precipitation with which the earth was formed, the great difference now found in the materials that compose its crust, and the mountains and vallies to the laws of gravity. He maintains that before the deluge the water of the present ocean was dispersed over the earth in small caverns, and that the mountains were at greater distances, and not so large as at present; but that the earth was a thousand times more fertile, and contained a great many more inhabitants, whose lives were ten times longer. All this he is of opinion was effected by the superior heat of the nucleus; but that this heat augmented the passions and destroyed the virtue of man and the sagacity of other animals, and caused the universal sentence of death which was inflicted by the deluge. He says, that that event was occasioned by a change in the inclination of the earth's axis, occasioned by the tail of a comet meeting with the earth, in returning from its perihelium, when "the cataracts of heaven were opened." Newton denied that there was any thing in astronomy wherefrom to presume this change of inclination. But the celebrated Count de Buffon left his predecessors far behind, after premising that the sphere of the sun's attraction is not limited by the orbits of the planets, but extends indefinitely, always decreasing according to the squares of the augmented distances: that the comets which escape our sight in the heavenly regions are, like the planets, subject to the attraction of the sun, and by it their motions are regulated: that all these bodies (the directions of which are so various,) move round the sun, and describe areas proportioned to their periods; the planets in ellipses, more or less circular, and the comets in narrow ellipses of vast extent.—He asserts, that comets run through the system in all directions; but that the inclinations of the planes of their orbits are so very different, that though, like the planets, they are subject to the laws of attraction, they have nothing in common with regard to their progressive or impulsive motions, but appear in this respect to be absolutely independent of each other.

He then conjectures that a comet, falling obliquely into the body of the sun, drove off a part from its surface, and communicated to it a violent impulsive force. This effect he supposes was produced at the time when God is said, by Moses, to have "separated the light from the darkness," by which Buffon understands a real, physical separation; the opaque bodies of the planets being detached from the luminous matter of which he supposed the sun to be composed, and he imagined that the part struck off was one six hundred and fiftieth part of the sun's body.

He informs us that this matter issued from the sun, not in the form of globes, but of liquid torrents of fire; and that a projectile motion having been communicated by the stroke of the comet, the light particles separated from the dense, which, by their mutual attractions, formed globes of different solidities; and that the projectile force being proportioned to the density of the particles, determined the respective distances from the sun to which they would be carried. Our author having thus (at one blow of a comet) created the planets out of the superabundant materials of the sun, and having driven them to the distances of their spheres from that body, was put to a great straight to prevent them from obeying the law of projectiles, in returning whence they issued, and in obliging them to revolve round a common centre. This part of his theory is very lame indeed. He first unphilosophically ascribes this change of direction to an acceleration of velocity; and secondly, the acceleration he very erroneously supposed would take place by the anterior particles attracting and hastening the posterior ones, and by the posterior ones pushing forward or hastening the anterior ones. But appearing to be unsatisfied himself with this explanation, he next makes the shock of the comet remove the sun from its former situation—so that when the planets, according to the law of projectiles, returned to the place from whence they had departed, they did not enter into the sun again, who had thus fortunately stepped out of their way, or Buffon's ingenious creation would have been entirely destroyed.

But to proceed. He supposes that the earth, having acquired its present shape by its motion while in a liquid state, the fire was eventually extinguished by its rapid passage through space, or after having consumed all the combustible matter it contained. Mr. Buffon acknowledges that the constituent parts of the earth's crust are now of very different densities; but he gives no satisfactory explanation for the change which must have taken place, if as he supposed, they were once homogeneous. Nor does he account for the separation of the land from the water. It is true he leaves us to infer that such a separation took place; for he says, that "the motion of the waters is coeval with time." He also says, that the waters occupy the lowest grounds, and that all the mountains have been formed at the bottom of the sea, by means of currents and tides. His primeval world must therefore have had cavities, in which the waters were preserved.

Such is the theory of the Count de Buffon, a gentleman of great ingenuity, taste and erudition; whose works, so long as he confined himself to facts and reasoning, have been universally admired; but whose theories have been as much ridiculed by others as he ridiculed those of Burnet and Whiston. Soon after the publication of this theory, Buffon was summoned before the Faculty of Theology at Paris, and there informed that fourteen propositions in his works were reprehensible and contrary to the creed of the church. One of these, which related to geology, was, "That the waters of the sea were concerned in producing the mountains and valleys of the land." And it is curious to remark that this, which was almost the only correct geological proposition in the whole work, Buffon publicly renounced! Upon this theory of Buffon I would take leave, upon the highest modern authority, further to observe, that "from a long series of observations, made with powerful telescopes, Herschel discovered that the solar light and heat do not emanate from the body or nucleus of the sun, but from certain phosphoric and pyrophoric clouds, which are produced and developed in its atmosphere. That this immense ocean of light is violently agitated over its whole surface, causing those corrugations of its disc which he has so well described,—and which indeed, may be observed through a telescope of moderate powers, by even an unpractised eye. When this superficial structure is broken through and widely separated, we may discern the black veil of subjacent solar clouds, or even the solid dark nucleus of the sun itself. Hence Herschel accounts for the dark spots which are frequently observed on the sun's disc, and for the shelving margins which surround them.—Across these excavations of the phosphoric film, bridges of luminous matter, are seen to stretch, which extending in breadth, finally cause the dark chasm to disappear, and restore to the sun all its original brightness. The area of one of these black spots is often much greater than the whole surface of the terrestrial globe. When the storm subsides in the solar atmosphere, the equilibrium of its clouds replaces the layer of light. It is well known that these spots, first observed by Gallileo, led to the discovery of the sun's motion round its axis, and showed that this motion is accomplished in twenty-five and a half days."

Had Buffon been acquainted with these great excavations of luminous matter, he would probably have ascribed them to a projection of the solar substance giving origin to some new planet or comet, and causing diminution of the sun's heat proportional to the darkened portion of its orb. But Herschel has shown, on the contrary, that the seasons in which the solar spots are most abundant, are characterized not by decreased light and heat to the earth, but apparently by an opposite result. He hence infers, that these spots correspond, and are owing to an increased activity in the vibratory motions, by which the sun excites the ether, diffused through space.

The new improvements in optics, afford a very unexpected means of determining whether it be true, as Herschel imagined, that the solar light does issue from an incandescent solid or fluid. When such a body, raised to a very high temperature, becomes luminous, the rays which fly off in all directions, do not come from the outer surface only, but also proceed, as the rays of heat do, from a multitude of material points placed beneath or within the surface, to a certain depth, extremely small indeed, but actually existing. Now, such of those rays as traverse the envelope of the heated mass obliquely, acquire and preserve a peculiar property, which can be rendered sensible by experiment; they are polarised. But if the same mass, instead of being rendered luminous by its proper temperature, be only covered with an exterior film of flame, which is the source of its light, the rays do not then possess this property.

Science has thus been enabled to submit to this singular test, the light which the sun sends to us. M. Arago, the author of this beautiful experiment, has in fact discovered that the rays of the sun, when transmitted even obliquely, are not polarised.

These results are fatal to the theory of Buffon. Those who belong to his school, if any remain, can no longer contend for the sun as the eternal furnace from which to make ignited spheres; but on the contrary, the nucleus of that luminary may possibly enjoy a habitable planetary temperature.

In 1788 Werner published, by his lectures, his famous theory of the earth. He supposed that at some former period this globe had, for a long time, been covered with water to a greater depth than the original altitude of the highest mountains. That this immense body of water was then tranquil, or nearly so, and contained in solution all the materials of all the rocks of which the present crust of the earth is composed. That in this state, chemical deposites, exhibiting more or less of a crystalline structure, were first gradually made, and invested the nucleus of the earth. That these chemical deposites constitute the primitive rocks, including the granite and trap, and are distinguished by their crystalline form, and by the total absence of organic remains. That during this period, most of the highest mountains were formed; but by a gradual subsidence of the waters the summits of these mountains were left naked, the tranquillity of the waters was disturbed, and currents were consequently produced. That by these currents the naked rocks were worn and partially disintegrated; and the grains or fragments thus produced, were diffused through the mass of water. That the rocks formed at this period would, of course, consist partly of chemical and partly of mechanical deposites. That they would also lie over the primitive rocks, but in consequence of the diminished altitude of the waters, they would appear at a lower level, often resting on the declivities of primitive mountains. That as organic remains make their first appearance in the rocks of this period, it is inferred that the rocky shores which had recently emerged from the great deep, were then passing into a habitable state. That the level of the great ocean continuing to sink, more extensive portions of the earth were left exposed to the increasing violence of the currents, and the solution, which was originally chemical, now became, in a great degree, composed of grains, or comminuted fragments, detached from the older rocks, and that hence the minerals of this period consist of mechanical deposites; that they lie over the two preceding classes and at a lower level, in consequence of the greater subsidence of the waters.

That extensive portions of the globe having now become dry, new species and genera inhabited the waters and dwelt upon the land, while numerous vegetables adorn the shores and other parts of the earth. Hence these rocks abound with organic remains, both animal and vegetable.

Doctor Hutton published his theory about the year 1795; he supposed that all the solid parts which form the crust of the present globe, have proceeded from the disintegration and destruction of former continents, by the gradual action of the atmosphere and water; that the ruins of those ancient continents were transported by water, and deposited at the bottom of ancient seas; and that these heterogeneous materials thus deposited, were consolidated by the action of subterraneous fires; and, by the same agents, were subsequently elevated to form the present continents. That gneiss and other stratified rocks were only softened, elevated, and sometimes variously inclined; while granite and other unstratified minerals were completely fused, and in many cases forced upwards by this powerful agent through the incumbent strata. That as this earth had arisen from the ruins of an anterior world, so that had originated from the ruins of a former one, and so ad infinitum.

Each of the two last theories obtained numerous advocates; and a flame of controversy respecting them was kindled, that for some years blazed throughout Europe with great fury. As usual, both parties claimed the victory; but impartial readers appear to think that while each party may lay some claims to correctness, yet as an entire theory both are in the wrong.

(To be continued.)

A great mind may change its objects, but it cannot relinquish them; it must have something to pursue: Variety is its relaxation, and amusement its repose.

For the Southern Literary Messenger.