Barr's Buffon.

Buffon's Natural History.

CONTAINING
A THEORY OF THE EARTH,
A GENERAL
HISTORY OF MAN,
OF THE BRUTE CREATION, AND OF
VEGETABLES, MINERALS,
&c. &c.

FROM THE FRENCH.

WITH NOTES BY THE TRANSLATOR.

IN TEN VOLUMES.

VOL. I.

London:
PRINTED FOR THE PROPRIETOR,
AND SOLD BY H. D. SYMONDS, PATERNOSTER-ROW.
1797.

CONTENTS
OF
THE FIRST VOLUME.

PREFACE.

We should certainly be guilty of a gross absurdity if, in an age like the present, we were to enter into an elaborate discussion on the advantages to be derived from the study of Natural History; the ancients recommended it as useful, instructive, and entertaining; and the moderns have so far pursued and cultivated this first of sciences, that it is now admitted to be the source of universal instruction and knowledge; where every active mind may find subjects to amuse and delight, and the artist a never failing field to enrich his glowing imagination.

It would have been singular if, on such a subject, a number of authors had not submitted the produce of their observations and labour; many have written upon Natural Philosophy, but the Comte de Buffon stands eminently distinguished among them; he has entered into a minute investigation, and drawn numberless facts from unwearied observations far beyond any other, and this he has accomplished in a style fully accordant with the importance of his subject. Ray, Linnæus, Rheaumur, and other of his cotemporaries, deserve much credit for their classing of animals, vegetables, &c. but it was Buffon alone who entered into a description of their nature, habits, uses, and properties. In his Theory of the Earth he has displayed a wonderful ingenuity, and shewn the general order of Nature with a masterly hand, although he may be subject to some objections for preferring physical reasonings on general

causes, rather than allowing aught to have arisen from supernatural agency, or the will of the Almighty. In this he has followed the example of all great philosophers, who seem unwilling to admit that the formation of any part of the Universe is beyond their comprehension.

As the works of this Author will best speak for themselves, we shall avoid unnecessary panegyric, hoping they will have received no material injury in the following translation; we shall therefore content ourselves with observing, that in our plan we have followed that adopted by the Comte himself in a latter edition, from which he exploded his long and minute treatises on anatomy and mensuration; though elegant and highly finished in themselves, they appeared to us of too abstruse and confined a nature for general estimation, and which we could not have gone into without almost doubling

the expence; a circumstance we had to guard against, for the advantage of those of our readers to whom that part would have been totally uninteresting.

As to this edition, we presume it is no vain boast, that every exertion has been made to do justice to a work of such acknowledged merit. In the literary part, it has been the Proprietor's chief endeavour to preserve the spirit and accuracy of the Author, as far as could be done in translating from one language into another; and it is with gratitude he acknowledges, that those endeavours have been amply supported by the engraver; for the decorative executions of Milton will remain a lasting monument of his abilities, as long as delicacy in the arts is held in estimation.

BUFFON's
NATURAL HISTORY.

THE THEORY OF THE EARTH.

Neither the figure of the earth, its motion, nor its external connections with the rest of the universe, pertain to our present investigation. It is the internal structure of the globe, its composition, form, and manner of existence which we purpose to examine. The general history of the earth should doubtless precede that of its productions, as a necessary study for those who wish to be acquainted with Nature in her variety of shapes,

and the detail of facts relative to the life and manners of animals, or to the culture and vegetation of plants, belong not, perhaps, so much to Natural History, as to the general deductions drawn from the observations that have been made upon the different materials which compose the terrestrial globe: as the heights, depths, and inequalities of its form; the motion of the sea, the direction of mountains, the situation of rocks and quarries, the rapidity and effects of currents in the ocean, &c. This is the history of nature in its most ample extent, and these are the operations by which every other effect is influenced and produced. The theory of these effects constitutes what may be termed a primary science, upon which the exact knowledge of particular appearances as well as terrestrial substances entirely depends. This description of science may fairly be considered as appertaining to physics; but does not all physical knowledge, in which no system is admitted, form part of the History of Nature?

In a subject of great magnitude, whose relative connections are difficult to trace, and where some facts are but partially known, and others uncertain and obscure, it is more easy

to form a visionary system, than to establish a rational theory; thus it is that the Theory of the Earth has only hitherto been treated in a vague and hypothetical manner; I shall therefore but slightly mention the singular notions of some authors who have written upon the subject.

The first hypothesis I shall allude to, deserves to be mentioned more for its ingenuity than its reasonable solidity; it is that of an English astronomer, (Whiston) versed in the system of Newton, and an enthusiastic admirer of his philosophy; convinced that every event which happens on the terrestrial globe, depends upon the motions of the stars, he endeavours to prove, by the assistance of mathematical calculations, that the tail of a comet has produced every alteration the earth has ever undergone.

The next is the formation of an heterodox theologician, (Burnet) whose brain was so heated with poetical visions, that he imagined he had seen the creation of the universe. After explaining what the earth was in its primary state, when it sprung from nothing; what changes were occasioned by the deluge; what it has been and what it is, he then assumes a

prophetic style, and predicts what will be its state after the destruction of the human race.

The third comes from a writer (Woodward) certainly a better and more extensive observer of nature than the two former, though little less irregular and confused in his ideas; he explains the principal appearances of the globe, by an immense abyss in the bowels of the earth, which in his opinion is nothing more than a thin crust that serves as a covering to the fluid it incloses.

The whole of these hypotheses are raised on unstable foundations; have given no light upon the subject, the ideas being unconnected, the facts confused, and the whole confounded with a mixture of physic and fable; and consequently have been adopted only by those who implicitly believe opinions without investigation, and who, incapable of distinguishing probability, are more impressed with the wonders of the marvellous than the relation of truth.

What we shall say on this subject will doubtless be less extraordinary, and appear unimportant, if put in comparison with the grand systems just mentioned, but it should be remembered that it is an historian's business to describe, not

invent; that no suppositions should be admitted upon subjects that depend upon facts and observation; that his imagination ought only to be exercised for the purpose of combining observations, rendering facts more general, and forming one connected whole, so as to present to the mind a distinct arrangement of clear ideas and probable conjectures; I say probable, because we must not expect to give exact demonstration on this subject, that being confined to mathematical sciences, while our knowledge in physics and natural history depends solely upon experience, and is confined to reasoning upon inductions.

In the history of the Earth, we shall therefore begin with those facts that have been obtained from the experience of time, together with what we have collected by our own observations.

This immense globe exhibits upon its surface heights, depths, plains, seas, lakes, marshes, rivers, caverns, gulphs, and volcanos; and upon the first view of these objects we cannot discover in their dispositions either order or regularity. If we penetrate into its internal part, we shall there find metals, minerals, stones, bitumens, sands, earths, waters, and

matters of every kind, placed as it were by chance, and without the smallest apparent design. Examining with a more strict attention, we discover sunk mountains, caverns filled, rocks split and broken, countries swallowed up, and new islands rising from the ocean; we shall also perceive heavy substances placed above light ones, hard bodies surrounded with soft; in short, we shall there find matter in every form, wet and dry, hot and cold, solid and brittle, mixed in such a sort of confusion as to leave room to compare them only to a mass of rubbish and the ruins of a wrecked world.

We inhabit these ruins however with a perfect security. The various generations of men, animals, and plants, succeed each other without interruption; the earth produces fully sufficient for their subsistence; the sea has its limits; its motions and the currents of air are regulated by fixed laws: the returns of the seasons are certain and regular; the severity of the winter being constantly succeeded by the beauties of the spring: every thing appears in order, and the earth, formerly a CHAOS, is now a tranquil and delightful abode, where all is animated, and regulated by such an amazing display of power and intelligence as fills us

with admiration, and elevates our minds with the most sublime ideas of an all-potent and wonderful Creator.

Let us not then draw any hasty conclusions upon the irregularities of the surface of the earth, nor the apparent disorders in the interior parts, for we shall soon discover the utility, and even the necessity of them; and, by considering them with a little attention, we shall, perhaps, find an order of which we had no conception, and a general connection that we could neither perceive nor comprehend, by a slight examination: but in fact, our knowledge on this subject must always be confined. There are many parts of the surface of the globe with which we are entirely unacquainted, and have but partial ideas of the bottom of the sea, which in many places we have not been able to fathom. We can only penetrate into the coat of the earth; the greatest caverns and the deepest mines do not descend above the eight thousandth part of its diameter, we can therefore judge only of the external and mere superficial part; we know, indeed, that bulk for bulk the earth weighs four times heavier than the sun, and we also know the proportion its weight bears with other planets; but this

is merely a relative estimation; we have no certain standard nor proportion; we are so entirely ignorant of the real weight of the materials, that the internal part of the globe may be a void space, or composed of matter a thousand times heavier than gold; nor is there any method to make further discoveries on this subject; and it is with the greatest difficulty any rational conjectures can be formed thereon.

We must therefore confine ourselves to a correct examination and description of the surface of the earth, and to those trifling depths to which we have been enabled to penetrate. The first object which presents itself is that immense quantity of water which covers the greatest part of the globe; this water always occupies the lowest ground, its surface always level, and constantly tending to equilibrium and rest; nevertheless it is kept in perpetual agitation by a powerful agent, which opposing its natural tranquillity, impresses it with a regular periodical motion, alternately raising and depressing its waves, producing a vibration in the total mass, by disturbing the whole body to the greatest depths. This motion we know has existed from the commencement of time,

and will continue as long as the sun and moon, which are the causes of it.

By an examination of the bottom of the sea, we discover that to be fully as irregular as the surface of the earth; we there find hills and vallies, plains and cavities, rocks and soils of every kind: we there perceive that islands are only the summits of vast mountains, whose foundations are at the bottom of the Ocean; we also find other mountains whose tops are nearly on a level with the surface of the water, and rapid currents which run contrary to the general movement: they sometimes run in the same direction, at others, their motions are retrograde, but never exceeding their bounds, which appear to be as fixed and invariable as those which confine the rivers of the earth. In one part we meet with tempestuous regions, where the winds blow with irresistible fury, where the sea and the heavens equally agitated, join in contact with each other, are mixed and confounded in the general shock: in others, violent intestine motions, tumultuous swellings, water-spouts, and extraordinary agitations, caused by volcanos, whose mouths though a considerable depth under water, yet vomit fire from the

midst of the waves, and send up to the clouds a thick vapour, composed of water, sulphur, and bitumen. Further we perceive dreadful gulphs or whirlpools, which seem to attract vessels, merely to swallow them up. On the other hand, we discover immense regions, totally opposite in their natures, always calm and tranquil, yet equally dangerous; where the winds never exert their power, where the art of the mariner becomes useless, and where the becalmed voyager must remain until death relieves him from the horrors of despair. In conclusion, if we turn our eyes towards the northern or southern extremities of the globe, we there perceive enormous flakes of ice separating themselves from the polar regions, advancing like huge mountains into the more temperate climes, where they dissolve and are lost to the sight.

Exclusive of these principal objects the vast empire of the sea abounds with animated beings, almost innumerable in numbers and variety. Some of them, covered with light scales, move with astonishing celerity; others, loaded with thick shells, drag heavily along, leaving their track in the sand; on others Nature has bestowed fins, resembling wings, with which

they raise and support themselves in the air, and fly to considerable distances; while there are those to whom all motion has been denied, who live and die immoveably fixed to the same rock: every species, however, find abundance of food in this their native element. The bottom of the sea, and the shelving sides of the various rocks, produce great abundance of plants and mosses of different kinds; its soil is composed of sand, gravel, rocks, and shells; in some parts a fine clay, in others a solid earth, and in general it has a complete resemblance to the land which we inhabit.

Let us now take a view of the earth. What prodigious differences do we find in different climates? What a variety of soils? What inequalities in the surface? but upon a minute and attentive observation we shall find the greatest chain of mountains are nearer the equator than the poles; that in the Old Continent their direction is more from the east to west than from the north to south; and that, on the contrary, in the New World they extend more from north to south than from east to west; but what is still more remarkable, the form and direction of those mountains, whose appearance is so very irregular, correspond so precisely, that

the prominent angles of one mountain are always opposite to the concave angles of the neighbouring mountain, and are of equal dimensions, whether they are separated by a small valley or an extensive plain. I have also observed that opposite hills are nearly of the same height, and that, in general, mountains occupy the middle of continents, islands, and promontories, which they divide by the greatest lengths.

In following the courses of the principal rivers, I have likewise found that they are almost always perpendicular with those of the sea into which they empty themselves; and that in the greatest part of their courses they proceed nearly in the direction of the mountains from which they derive their source.

The sea shores are generally bounded with rocks, marble, and other hard stones, or by earth and sand which has accumulated by the waters from the sea, or been brought down by the rivers; and I observe that opposite coasts, separated only by an arm of the sea, are composed of similar materials, and the beds of the earth are exactly the same. Volcanos I find exist only in the highest mountains; that many of them are entirely extinct; that some

are connected with others by subterraneous passages, and that their explosions frequently happen at one and the same time. There are similar correspondences between certain lakes and neighbouring seas; some rivers suddenly disappear, and seem to precipitate themselves into the earth. We also find internal, or mediterranean seas, constantly receiving an enormous quantity of water from a number of rivers without ever extending their bounds, most probably discharging by subterraneous passages all their superfluous supplies. Lands which have been long inhabited are easily distinguished from those new countries where the soil appears in a rude state, where the rivers are full of cataracts, where the earth is either overflowed with water, or parched up with drought, and where every spot upon which a tree will grow is covered with uncultivated woods.

Pursuing our examination in a more extensive view, we find that the upper strata that surrounds the globe, is universally the same. That this substance which serves for the growth and nourishment of animals and vegetables, is nothing but a composition of decayed animal and vegetable bodies reduced into such small particles, that their former organization

is not distinguishable; or penetrating a little further, we find the real earth, beds of sand, lime-stone, argol, shells, marble, gravel, chalk, &c. These beds are always parallel to each other and of the same thickness throughout their whole extent. In neighbouring hills beds of the same materials are invariably found upon the same levels, though the hills are separated by deep and extensive intervals. All beds of earth, even the most solid strata, as rocks, quarries of marble, &c. are uniformly divided by perpendicular fissures; it is the same in the largest as well as smallest depths, and appears a rule which nature invariably pursues.

In the very bowels of the earth, on the tops of mountains, and even the most remote parts from the sea, shells, skeletons of fish, marine plants, &c. are frequently found, and these shells, fish, and plants, are exactly similar to those which exist in the Ocean. There are a prodigious quantity of petrified shells to be met with in an infinity of places, not only inclosed in rocks, masses of marble, lime-stone, as well as in earth and clays, but are actually incorporated and filled with the very substance which surrounds them. In short, I find myself convinced, by repeated observations,

that marbles, stones, chalks, marls, clay, sand, and almost all terrestrial substances, wherever they may be placed, are filled with shells and other substances, the productions of the sea.

These facts being enumerated, let us now see what reasonable conclusions are to be drawn from them.

The changes and alterations which have happened to the earth, in the space of the last two or three thousand years, are very inconsiderable indeed, when compared with those important revolutions which must have taken place in those ages which immediately followed the creation; for as all terrestrial substances could only acquire solidity by the continued action of gravity, it would be easy to demonstrate that the surface of the earth was much softer at first than it is at present, and consequently the same causes which now produce but slight and almost imperceptible changes during many ages, would then effect great revolutions in a very short space. It appears to be a certain fact, that the earth which we now inhabit, and even the tops of the highest mountains, were formerly covered with the sea, for shells and other marine productions are frequently found in almost every part; it appears also that the

water remained a considerable time on the surface of the earth, since in many places there have been discovered such prodigious banks of shells, that it is impossible so great a multitude of animals could exist at the same time: this fact seems likewise to prove, that although the materials which composed the surface of the earth were then in a state of softness, that rendered them easy to be disunited, moved and transported by the waters, yet that these removals were not made at once; they must indeed have been successive, gradual, and by degrees, because these kind of sea productions are frequently met with more than a thousand feet below the surface, and such a considerable thickness of earth and stone could not have accumulated but by the length of time. If we were to suppose that at the Deluge all the shell-fish were raised from the bottom of the sea, and transported over all the earth; besides the difficulty of establishing this supposition, it is evident, that as we find shells incorporated in marble and in the rocks of the highest mountains, we must likewise suppose that all these marbles and rocks were formed at the same time, and that too at the very instant of the Deluge; and besides, that previous to this

great revolution there were neither mountains, marble, nor rocks, nor clays, nor matters of any kind similar to those we are at present acquainted with, as they almost all contain shells and other productions of the sea. Besides, at the time of the Deluge, the earth must have acquired a considerable degree of solidity, from the action of gravity for more than sixteen centuries, and consequently it does not appear possible that the waters, during the short time the Deluge lasted, should have overturned and dissolved its surface to the greatest depths we have since been enabled to penetrate.

But without dwelling longer on this point, which shall hereafter be more amply discussed, I shall confine myself to well-known observations and established facts. There is no doubt but that the waters of the sea at some period covered and remained for ages upon that part of the globe which is now known to be dry land; and consequently the whole continents of Asia, Europe, Africa, and America, were then the bottom of an ocean abounding with similar productions to those which the sea at present contains: it is equally certain that the different strata which compose the earth are parallel and horizontal, and it is evident their

being in this situation is the operation of the waters which have collected and accumulated by degrees the different materials, and given them the same position as the water itself always assumes. We observe that the position of strata is almost universally horizontal: in plains it is exactly so, and it is only in the mountains that they are inclined to the horizon, from their having been originally formed by a sediment deposited upon an inclined base. Now I insist that these strata must have been formed by degrees, and not all at once, by any revolution whatever, because strata, composed of heavy materials, are very frequently found placed above light ones, which could not be, if, as some authors assert, the whole had been mixed with the waters at the time of the Deluge, and afterwards precipitated; in that case every thing must have had a very different appearance to that which now exists. The heaviest bodies would have descended first, and each particular stratum would have been arranged according to its weight and specific gravity, and we should not see solid rocks or metals placed above light sand any more than clay under coal.

We should also pay attention to another circumstance; it confirms what we have said on the formation of the strata; no other cause than the motions and sediments of water could possibly produce so regular a position of it, for the highest mountains are composed of parallel strata as well as the lowest plains, and therefore we cannot attribute the origin and formation of mountains to the shocks of earthquakes, or eruptions of volcanos. The small eminences which are sometimes raised by volcanos, or convulsive motions of the earth, are not by any means composed of parallel strata, they are a mere disordered heap of matters thrown confusedly together; but the horizontal and parallel position of the strata must necessarily proceed from the operations of a constant cause and motion, always regulated and directed in the same uniform manner.

From repeated observations, and these incontrovertible facts, we are convinced that the dry part of the globe, which is now habitable, has remained for a long time under the waters of the sea, and consequently this earth underwent the same fluctuations and changes which the bottom of the ocean is at present actually undergoing. To discover therefore what

formerly passed on the earth, let us examine what now passes at the bottom of the sea, and from thence we shall soon be enabled to draw rational conclusions with regard to the external form and internal composition of that which we inhabit.

From the Creation the sea has constantly been subject to a regular flux and reflux: this motion, which raises and falls the waters twice in every twenty-four hours, is principally occasioned by the action of the moon, and is much greater under the equator than in any other climates. The earth performs a rapid motion on its axis, and consequently has a centrifugal force, which is also the greatest at the equator; this latter, independent of actual observation, proves that the earth is not perfectly spherical, but that it must be more elevated under the equator then at the poles.

From these combined causes, the ebbing and flowing of the tides, and the motion of the earth, we may fairly conclude, that although the earth was a perfect sphere in its original form, yet its diurnal motion, together with the constant flux and reflux of the sea, must, by degrees, in the course of time, have raised the equatorial parts, by carrying mud, earth, sand,

shells, &c. from other climes, and there depositing of them. Agreeable to this idea the greatest irregularities must be found, and, in fact, are found near the equator. Besides, as this motion of the tides is made by diurnal alternatives, and been repeated, without interruption, from the commencement of time, is it not natural to imagine, that each time the tide flows the water carries a small quantity of matter from one place to another, which may fall to the bottom like a sediment, and form those parallel and horizontal strata which are every where to be met with? for the whole motion of the water, in the flux and reflux, being horizontal, the matters carried away with them will naturally be deposited in the same parallel direction.

But to this it may be said, that as the flux and reflux of the waters are equal and regularly succeed, two motions would counterpoise each other, and the matters brought by the flux would be returned by the reflux, and of course this cause for the formation of the strata must be chimerical; that the bottom of the sea could not experience any material alteration by two uniform motions, wherein the effects of the one would be regularly destroyed

by the other; much less could they change the original form by the production of heights and inequalities.

To which it may be answered, that the alternate motions of the waters are not equal, the sea having a constant motion from the east to the west, besides, the agitation, caused by the winds, opposes and prevents the equality of the tides. It will also be admitted, that by every motion of which the sea is susceptible, particles of earth and other matters will be carried from one place and deposited in another; and these collections will necessarily assume the form of horizontal and parallel strata, from the various combinations of the motions of the sea always tending to move the earth, and to level these materials wherever they fall, in the form of a sediment. But this objection is easily obviated by the well-known fact, that upon all coasts, bordering the sea, where the ebbing and flowing of the tide is observed, the flux constantly brings in a number of things which the reflux does not carry back. There are many places upon which the sea insensibly gains and gradually covers over, while there are others from which it recedes, narrowing as it were its limits, by depositing earth, sands,

shells, &c. which naturally take an horizontal position; these matters accumulate by degrees in the course of time, and being raised to a certain point gradually exclude the water, and so become part of the dry land for ever after.

But not to leave any doubt upon this important point, let us strictly examine into the possibility of a mountain's being formed at the bottom of the sea by the motions and sediments of the waters. It is certain that on a coast which the sea beats with violence during the agitation of its flow, that every wave must carry off some part of the earth; for wherever the sea is bounded by rocks, it is a plain fact that the water by degrees wears away those rocks, and consequently carries away small particles every time the waves retire; these particles of earth and stone will necessarily be transported to some distance, and being arrived where the agitation of the water is abated, and left to their own weight, they precipitate to the bottom in form of a sediment, and there form a first stratum, either horizontal or inclined, according to the position of the surface upon which they fall; this will shortly be covered by a similar stratum produced by the same cause, and thus will a considerable quantity of matter

be almost insensibly collected together, and the strata of which will be placed, parallel to each other.

This mass will continue to increase by new sediments, and by gradually accumulating, in the course of time become a mountain at the bottom of the sea, exactly similar to those we see on dry land, both as to outward form and internal composition. If there happen to be shells in this part of the sea, where we have supposed this deposit to be made, they will be filled and covered with the sediment, and incorporated in the deposited matter, making a part of the whole mass, and they will be found situated in the parts of the mountain according to the time they had been there deposited; those that lay at the bottom, previous to the formation of the first stratum, will be found in the lowest, and so according to the time of their being deposited, the latest in the most elevated parts.

So likewise, when the bottom of the sea, at particular places, is troubled by the agitation of the water, there will necessarily ensue, in the same manner, a removal of earth, shells, and other matters, from the troubled to other parts; for we are assumed by all divers, that at

the greatest depths they descend, i. e. twenty fathoms, the bottom of the sea is so troubled by the agitation of the waters, that the mud and shells are carried to considerable distances, consequently transportations of this kind are made in every part of the sea, and this matter falling must form eminences, composed like our mountains, and in every respect similar; therefore the flux and reflux, by the winds, the currents, and all the motions of the water, must inevitably create inequalities at the bottom of the sea.

Nor must we imagine that these matters cannot be transported to great distances, because we daily see grain, and other productions of the East and West Indies, arriving on our own coasts.[25:A] It is true these bodies are specifically lighter than water, whereas the substances of which we have been speaking are specifically heavier; but, however, being reduced to an impalpable powder, they may be sustained a long time in the water so as to be conveyed to considerable distances.

It has been supposed that the sea is not troubled at the bottom, especially if it is very

deep, by the agitations produced by the winds and tides; but it should be recollected that the whole mass, however deep, is put in motion by the tides, and that in a liquid globe this motion would be communicated to the very centre; that the power which produces the flux and reflux is a penetrating force, which acts proportionably upon every particle of its mass, so that we can determine by calculation the quantity of its force at different depths; but, in short, this point is so certain, that it cannot be contested but by refusing the evidence of reason.

Therefore, we cannot possibly have the least doubt that the tides, the winds, and every other cause which agitates the sea, must produce eminences and inequalities at the bottom, and those heights must ever be composed of horizontal or equally inclined strata. These eminences will gradually encrease until they become hills, which will rise in situations similar to the waves that produce them; and if there is a long extent of soil, they will continue to augment by degrees; so that in course of time they will form a vast chain of mountains. Being formed into mountains, they become an obstacle to and interrupt the common

motion of the sea, producing at the same time other motions, which are generally called currents. Between two neighbouring heights at the bottom of the sea a current will necessarily be formed, which will follow their common direction, and, like a river, form a channel, whose angles will be alternately opposite during the whole extent of its course. These heights will be continually increasing, being subject only to the motion of the flux, for the waters during the flow will leave the common sediment upon their ridges; and those waters which are impelled by the current will force along with them, to great distances, those matters which would be deposited between both, at the same time hollowing out a valley with corresponding angles at their foundation. By the effects of these motions and sediments the bottom of the sea, although originally smooth, must become unequal, and abounding with hills and chains of mountains, as we find it at present. The soft materials of which the eminences are originally composed will harden by degrees with their own weight; some forming parts, purely angular, produce hills of clay; others, consisting of sandy and crystalline particles, compose those enormous masses of

rock and flint from whence crystal and other precious stones are extracted; those formed with stony particles, mixed with shells, form those of lime-stone and marble, wherein we daily meet with shells incorporated; and others, compounded of matter more shelly, united with pure earth, compose all our beds of marle and chalk. All these substances are placed in regular beds, and all contain heterogeneous matter; marine productions are found among them in abundance, and nearly according to the relation of their specific weights; the lightest shells in chalk, and the heaviest in clay and lime-stone; these shells are invariably filled with the matter in which they have been inclosed, whether stones or earth; an incontestible proof that they have been transported with the matter that fills and surrounds them, and that this matter was at that time in an impalpable powder. In short, all those substances whose horizontal situations have been established by the level of the waters of the sea, will constantly preserve their original position.

But here it may be observed, that most hills, whose summits consist of solid rocks, stone, or marble, are formed upon small eminences of much lighter materials, such for instance as

clay, or strata of sand, which we commonly find extended over the neighbouring plains, upon which it may be asked, how, if the foregoing theory be just, this seemingly contradictory arrangement happens? To me this phenomenon appears to be very easy and naturally explained. The water at first acts upon the upper stratum of coasts, or bottom of the sea, which commonly consists of clay or sand, and having transported this, and deposited the sediment, it of course composes small eminences, which form a base for the more heavy particles to rest upon. Having removed the lighter substances, it operates upon the more heavy, and by constant attrition reduces them to an impalpable powder; which it conveys to the same spot, and where, being deposited, these stony particles, in the course of time, form those solid rocks and quarries which we now find upon the tops of hills and mountains. It is not unlikely that as these particles are much heavier than sand or clay, that they were formerly a considerable depth under a strata of that kind, and now owe their high situations to having been last raised up and transported by the motion of the water.

To confirm what we here assert, let us more closely investigate the situation of those materials which compose the superficial outer part of the globe, indeed the only part with which we have any knowledge. The different beds of strata in stone quarries are almost all horizontal, or regularly inclined; those whose foundations are on clays or other solid matters are clearly horizontal, especially in plains. The quarries wherein we find flint, or brownish grey free-stone, in detached portions, have a less regular position, but even in those the uniformity of nature plainly appears, for the horizontal or regularly inclined strata are apparent in quarries where these stones are found in great masses. This position is universal, except in quarries where flint and brown free-stone are found in small detached portions, the formation of which we shall prove to have been posterior to those we have just been treating of; for granite, vitrifiable sand, argol, marble, calcareous stone, chalk, and marles, are always deposited in parallel strata, horizontally or equally inclined; the original formation of these are easily discovered, for the strata are exactly horizontal and very thin, and are arranged above each other like the leaves

of a book. Beds of sand, soft and hard clay, chalk, and shells, are also either horizontal or regularly inclined. Strata of every kind preserves the same thickness throughout its whole extent, which often occupies the space of many miles, and may be traced still farther by close and exact observations. In a word, the materials of the globe, as far as mankind have been enabled to penetrate, are arranged in an uniform position, and are exactly similar.

The strata of sand and gravel which have been washed down from mountains must in some measure be excepted; in vallies they are sometimes of a considerable extent, and are generally placed under the first strata of the earth; in plains, they are as even as the most ancient and interior strata, but near the bottom and upon the ridges of hills they are inclined, and follow the inclination of the ground upon which they have flowed. These being formed by rivers and rivulets, which are constantly in vallies changing their beds, and dragging these sands and gravel with them, they are of course very numerous. A small rivulet flowing from the neighbouring heights, in the course of time will be sufficient to cover a very spacious valley with a strata of sand and gravel, and I

have often observed in hilly countries, whose base, as well as the upper stratum, was hard clay, that above the source of the rivulet the clay is found immediately under the vegetable soil, and below it there is the thickness of a foot of sand upon the clay, and which extends itself to a considerable distance. These strata formed by rivers are not very ancient, and are easily discovered by the inequality of their thickness, which is constantly varying, while the ancient strata preserves the same dimensions throughout; they are also to be known by the matter itself, which bears evident marks of having been smoothed and rounded by the motions of the water. The same may be said of the turf and perished vegetables which are found below the first stratum of earth in marshy grounds; they cannot be considered as ancient, but entirely produced by successive heaps of decayed trees and other plants. Nor are the strata of slime and mud, which are found in many countries, to be considered as ancient productions, having been formed by stagnated waters or inundations of rivers, and are neither so horizontal, nor equally inclined, as the strata anciently produced by the regular motions of the sea. In the strata formed by rivers we

constantly meet with river, but scarcely ever sea shells, and the few that are found are broken and irregularly placed; whereas in the ancient strata there are no river shells; the sea shells are in great quantities, well preserved, and all placed in the same manner, having been transported at the same time and by the same cause. How are we to account for this astonishing regularity? Instead of regular strata, why do we not meet with the matters that compose the earth jumbled together, without any kind of order? Why are not rocks, marbles, clays, marles, &c. variously dispersed, or joined by irregular or vertical strata? Why are not the heaviest bodies uniformly found placed beneath the lightest? It is easy to perceive that this uniformity of nature, this organization of earth, this connection of different materials, by parallel strata, without respect to their weights, could only be produced by a cause as powerful and constant as the motion of the sea, whether occasioned by the regular winds or by that of the flux and reflux, &c.

These causes act with greater force under the equator than in other climates, for there the winds are more regular and the tides run

higher; the most extensive chains of mountains are also near the equator. The mountains of Africa and Peru are the highest known, they frequently extend themselves through whole provinces, and stretch, to considerable distances under the ocean. The mountains of Europe and Asia, which extend from Spain to China, are not so high as those of South America and Africa. The mountains of the North, according to the relation of travellers, are only hills in comparison with those of the Southern countries. Besides, there are very few islands in the Northern Seas, whereas in the torrid zone they are almost innumerable, and as islands are only the summits of mountains, it is evident that the surface of the earth has many more inequalities towards the equator than in the northerly climes.

It is therefore evident that the prodigious chain of mountains which run from the West to the East in the old continent, and from the North to the South in the new, must have been produced by the general motion of the tides; but the origin of all the inferior mountains must be attributed to the particular motions of currents, occasioned by the winds and other irregular agitations of the sea: they

may probably have been produced by a combination of all those motions, which must be capable of infinite variations, since the winds and different positions of islands and coasts change the regular course of the tides, and compel them to flow in every possible direction: it is, therefore, not in the least astonishing that we should see considerable eminences, whose courses have no determined direction. But it is sufficient for our present purpose to have demonstrated that mountains are not the produce of earthquakes, or other accidental causes, but that they are the effects resulting from the general order of nature, both as to their organization and the position of the materials of which they are composed.

But how has it happened that this earth which we and our ancestors have inhabited for ages, which, from time immemorial, has been an immense continent, dry and removed from the reach of the waters, should, if formerly the bottom of the ocean, be actually larger than all the waters, and raised to such a height as to be distinctly separated from them? Having remained so long on the earth, why have the waters now abandoned it? What accident, what cause could produce

so great a change? Is it possible to conceive one possessed of sufficient power to produce such an amazing effect?

These questions are difficult to be resolved, but as the facts are certain and incontrovertible, the exact manner in which they happened may remain unknown, without prejudicing the conclusions that may be drawn from them; nevertheless, by a little reflection, we shall find at least plausible reasons for these changes. We daily observe the sea gaining ground on some coasts and losing it on others; we know that the ocean has a continued regular motion from East to West; that it makes loud and violent efforts against the low lands and rocks which confine it; that there are whole provinces which human industry can hardly secure from the rage of the sea; that there are instances of islands rising above, and others being sunk under the waters. History speaks of much greater deluges and inundations. Ought not this to incline us to believe that the surface of the earth has undergone great revolutions, and that the sea may have quitted the greatest part of the earth which it formerly covered? Let us but suppose that the old and new worlds were formerly but one continent, and that the

Atlantis of Plato was sunk by a violent earthquake; the natural consequence would be, that the sea would necessarily have flowed in from all sides, and formed what is now called the Atlantic Ocean, leaving vast continents dry, and possibly those which we now inhabit. This revolution, therefore, might be made of a sudden by the opening of some vast cavern in the interior part of the globe, which an universal deluge must inevitably succeed; or possibly this change was not effected at once, but required a length of time, which I am rather inclined to think; however these conjectures may be, it is certain the revolution has occurred, and in my opinion very naturally; for to judge of the future, as well as the past, we must carefully attend to what daily happens before our eyes. It is a fact clearly established by repeated observations of travellers, that the ocean has a constant motion from the East to West; this motion, like the trade winds, is not only felt between the tropics, but also throughout the temperate climates, and as near the poles as navigators have gone; of course the Pacific Ocean makes a continual effort against the coasts of Tartary, China, and India; the Indian Ocean acts

against the east coast of Africa; and the Atlantic in like manner against all the eastern coasts of America; therefore the sea must have always and still continues to gain land on the east and lose it on the west; and this alone is sufficient to prove the possibility of the change Of earth into sea, and sea into land. If, in fact, such are the effects of the sea's motion from east to west, may we not very reasonably suppose that Asia and the eastern continent is the oldest country in the world, and that Europe and part of Africa, especially the western coasts of these continents, as Great Britain, France, Spain, Muratania, &c. are of a more modern date? Both history and physics agree in confirming this conjecture.

There are, however, many other causes which concur with the continual motion of the sea from east to west, in producing these effects.

In many places there are lands lower than the level of the sea, and which are only defended from it by an isthmus of rocks, or by banks and dykes of still weaker materials; these barriers must gradually be destroyed by the constant action of the sea, when the lands

will be overflowed, and constantly make part of the ocean. Besides, are not mountains daily decreasing by the rains, which loosen the earth, and carry it down into the vallies? It is also well known that floods wash the earth from the plains and high grounds into the small brooks and rivers, which in their turn convey it into the sea. By these means the bottom of the sea is filling up by degrees, the surface of the earth lowering to a level, and nothing but time is necessary for the sea's successively changing places with the earth.

I speak not here of those remote causes which stand above our comprehension; of those convulsions of nature, whose least effects would be fatal to the world; the near approach of a comet, the absence of the moon, the introduction of a new planet, &c. are suppositions on which it is easy to give scope to the imagination. Such causes would produce any effects we chose, and from a single hypothesis of this nature, a thousand physical romances might be drawn, and which the authors might term, THE THEORY OF THE EARTH. As historians we reject these vain speculations; they are mere possibilities which suppose the destruction

of the universe, in which our globe, like a particle of forsaken matter, escapes our observation, and is no longer an object worthy regard; but to preserve consistency, we must take the earth as it is, closely observing every part, and by inductions judge of the future from what exists at present; in other respects we ought not to be affected by causes which seldom happen, and whose effects are always sudden and violent; they do not occur in the common course of nature; but effects which are daily repeated, motions which succeed each other without interruption, and operations that are constant, ought alone to be the ground of our reasoning.

We will add some examples thereto; we will combine particular effects with general causes, and give a detail of facts which will render apparent, and explain the different changes that the earth has undergone, whether by the eruption of the sea upon the land, or by retiring from that which it had formerly covered.

The greatest eruption was certainly that which gave rise to the Mediterranean sea. The ocean flows through a narrow channel

between two promontories with great rapidity, and then forms a vast sea, which, without including the Black sea, is about seven times larger than the kingdom of France. Its motion through the straits of Gibraltar is contrary to all other straits, for the general motion of the sea is from east to west, but in that alone it is from the west to the east, which proves that the Mediterranean sea is not an ancient gulph, but that it has been formed by an eruption, produced by some accidental cause; as an earthquake which might swallow up the earth in the strait, or by a violent effort of the ocean, caused by the wind, which might have forced its way through the banks between the promontories of Gibraltar and Ceuta. This opinion is authorised by the testimony of the ancients, who declare in their writings, that the Mediterranean sea did not formerly exist; and confirmed by natural history and observations made on the opposite coasts of Spain, where similar beds of stones and earth are found upon the same levels, in like manner as they are in two mountains, separated by a small valley.

The ocean having forced this passage, it ran at first through the straits with much greater

rapidity than at present, and overflowed the continent that joined Europe to Africa. The waters covered all the low countries, of which we can only now perceive the tops of some of the considerable mountains, such as parts of Italy, the islands of Sicily, Malta, Corsica, Sardinia, Cyprus, Rhodes, and those of the Archipelago.

In this eruption I have not included the Black sea, because the quantity of water it receives from the Danube, Nieper, Don, and various other rivers, is fully sufficient to form and support it; and besides, it flows with great rapidity through the Bosphorus into the Mediterranean. It might also be presumed that the Black and Caspian seas were formerly only two large lakes, joined by a narrow communication, or by a morass, or small lake, which united the Don and the Wolga near Tria, where these two rivers flow near each other; nor is it improbable that these two seas or lakes were then of much greater extent, for the immense rivers which fall into the Black and Caspian seas may have brought down a sufficient quantity of earth to shut up the communication, and form that neck of land by which they are now separated; for we know great

rivers, in the course of time, fill up seas and form new land, as the province at the mouth of the Yellow river in China; Louisania at the mouth of the Mississippi, and the northern part of Egypt, which owes its existence to the inundations of the Nile; the rapidity of which brings down such quantities of earth from the internal parts of Africa, as to deposit on the shores, during the inundations, a body of slime and mud of more than fifty feet in depth. The province of the Yellow river and Louisania have, in like manner, been formed by the soil from the rivers.

The Caspian sea is actually a real lake; having no communication with other seas, not even with the lake Aral, which seems to have been a part of it, being only separated from it by a large track of sand, in which neither rivers nor canals for communication the waters have as yet been found. This sea, therefore, has no external communication with any other; and I do not know that we are authorised to suspect that it has an internal one with the Black sea, or with the Gulph of Persia. It is true the Caspian sea receives the Wolga and many other rivers, which seem to furnish it

with more water than is lost by evaporation; but independent of the difficulty of such calculation, if it had a communication with any other sea, a constant and rapid current towards the opening would have marked its course, and I never heard of any such discovery being made; travellers of the best credit affirm to the contrary, and consequently the Caspian sea must lose by evaporation just as much water as it receives from the Wolga and other rivers.

Nor is it any improbable conjecture that the Black sea will at some period be separated from the Mediterranean; and that the Bosphorus will be shut up, whenever the great rivers shall have accumulated a sufficient quantity of earth to answer that effect; this may be the case in the course of time by the successive diminution of waters in rivers, in proportion as the mountains from whence they draw their sources are lowered by the rains, and those other causes we have just alluded to.

The Caspian and Black seas must therefore be looked upon rather as lakes than gulphs of the ocean, for they resemble other lakes which receive a number of rivers without any

apparent outlet, such as the Dead sea, many lakes in Africa and other places. These two seas are not near so salt as the Mediterranean or the ocean; and all voyagers affirm that the navigation in the Black and Caspian seas, upon account of its shallowness and quantity of rocks and quicksands, is so extremely dangerous, that only small vessels can be used with safety which farther proves they must not be looked upon as gulphs of the ocean, but as immense bodies of water collected from great rivers.

A considerable eruption of the sea would doubtless take place upon the earth, if the isthmus which separates Africa from Asia was divided, as the Kings of Egypt, and afterwards the Caliphs projected; and I do not know that the communication between the Red sea and Mediterranean is sufficiently established, as the former must be higher than the latter. The Red sea is a narrow branch of the ocean, and does not receive into it a single river on the side of Egypt, and very few on the opposite coast; it will not therefore be subject to diminution, like those seas and lakes which are constantly receiving slime and sand from those rivers that flow into them. The

ocean supplies the Red sea with all its water, and the motion of the tides is very evident in it, of course it must be affected by every movement of the ocean. But the Mediterranean must be lower than the ocean, because the current passes with great rapidity through the straits; besides, it receives the Nile, which flows parallel to the west coast of the Red sea, and which divides Egypt, a very low country; from all which it appears probable, that the Red sea is higher than the Mediterranean, and that if the isthmus of Suez was cut through, there Would be a great inundation, and a considerable augmentation of the Mediterranean would ensue; at least if the waters were not restrained by dykes and sluices placed at proper distances, and which was most likely the case if the ancient canal of communication ever had existence.

Without dwelling longer upon conjectures, which, although well founded, may appear hazardous and rash, we shall give some recent and certain examples of the change of the sea into land, and the land into sea. At Venice the bottom of the Adriatic is daily rising, and if great care had not been taken to clean and empty the canals, the whole would long since

have formed part of the continent; the same may be said of most ports, bays, and mouths of rivers. In Holland the bottom of the sea has risen in many places; the gulph of Zuyderzee and the strait of the Texel cannot receive such large vessels as formerly. At the mouth of all rivers we find small islands, and banks of sand and earth brought down by the waters, and it is certain the sea will be filled up in every part where great rivers empty themselves. The Rhine is lost in the sands which itself accumulated. The Danube and the Nile, and all great rivers, after bringing down much sand and earth, no longer come to the sea by a single channel; they divide into different branches, and the intervals are filled up by the materials they have themselves brought thither. Morasses daily dry up; lands forsaken by the sea are cultivated; we navigate countries now covered by waters; in short, we see so many instances of land changing into water, and water into land, that we must be convinced of these alterations having, and will continue to take place; so that in time gulphs will become continents; isthmusses, straits; morasses, dry lands; and

the tops of our mountains, the shoals of the sea.

Since then the waters have covered, and may successively cover, every part of the present dry land, our surprise must cease at finding every where marine productions and compositions, which could only be the works of the waters. We have already explained how the horizontal strata of the earth were formed, but the perpendicular divisions that are commonly found in rocks, clays, and all matters of which the globe is composed, still remain to be considered. These perpendicular stratas are, in fact, placed much farther from each other than the horizontal, and the softer the matter the greater the distance; in marble and hard earths they are frequently found only a few feet; but if the mass of rock be very extensive, then these fissures are at some fathoms distant; sometimes they descend from the top of the rock to the bottom, and sometimes terminate at an horizontal fissure. They are always perpendicular in the strata of calcinable matters, as chalk, marle, marble, &c. but are more oblique and irregularly placed in vitrifiable substances, brown freestone, and rocks of flint, where they are frequently adorned with

chrystals, and other minerals. In quarries of marble or calcinable stone, the divisions are filled with spar, gypsum, gravel, and an earthy sand, which contains a great quantity of chalk. In clay, marls, and every other kind of earth, excepting turf, these perpendicular divisions are either empty or filled with such matters as the water has transported thither.

We need seek very little farther for the cause and origin of those perpendicular cracks. The materials by which the different strata are composed being carried by the water, and deposited as a kind of sediment, must necessarily, at first, contain a considerable share of water, the which, as they began to harden, they would part with by degrees, and, as they must necessarily lessen in the course of drying, that decrease would occasion them to split at irregular distances. They naturally split in a perpendicular direction, because in that direction the action of gravity of one particle upon another has no actual effect, while, on the contrary, it is directly opposite in a horizontal situation; the diminution of bulk therefore could have no sensible effect but in a vertical line. I say it is the diminution of drying, and not the

contained water forcing a place to issue, is the cause of these perpendicular fissures, for I have often observed that the two sides of those fissures answer throughout their whole height, as exactly as two sides of a split piece of wood; their insides are rough and irregular, whereas if they had been made by the motion of the water, they would have been smooth and polished; therefore these cracks must be produced suddenly and at once or by degrees in drying, like the flaws in wood, and the greatest part of the water they contained evaporated through the pores. The divisions of these perpendicular cracks vary greatly as to the extent of their openings; some of them being not more than half an inch, others increasing to one or two feet; there are some many fathoms, and which form those precipices so often met with in the Alps and other high mountains. The small ones are produced by drying alone, but those which extend to several feet are the effects of other causes; for instance, the sinking of the foundation on one side while the other remains unmoved; if the base sinks but a line or two, it is sufficient to produce openings of many feet in a rock of considerable height. Sometimes rocks, which are founded on clay or

sand, incline to one side, by which motion the perpendicular cracks become extended.

I have not yet mentioned those large openings which are found in rocks and mountains; they must have been produced by great sinkings, as of immense caverns, unable longer to support the weight with which they were encumbered, but these intervals are very different from perpendicular fissures; they appear to be vacancies opened by the hand of Nature for the communication of nations. In this manner all vacancies in large mountains and divisions, by straits in the sea, seem to present themselves; such as the straits of Thermopylæ, the ports of Caucasus, the Cordeliers, the extremity of the straits of Gibraltar, the entrance of the Hellespont, &c. These could not have been occasioned by the simple separation by drying of matter, but by considerable parts of the lands themselves being sunk, swallowed up, or overturned.

These great sinkings, though produced by accidental causes, hold a first place in the principal circumstances in the History of the Earth, and not a little contributed to change the face of the Globe; the greatest part of them have been produced by subterraneous fires, whose

explosions cause earthquakes and volcanos; the force of these inflamed and confined matters in the bowels of the earth is beyond compare; by it cities have been swallowed up, provinces overturned, and mountains overthrown. But however great this force may be, and prodigious as the effects appear, we cannot assent to the opinion of those authors who suppose these subterraneous fires proceed from an immense abyss of flame in the centre of the earth, neither give we credit to the common notion that they proceed from a great depth below the surface of the earth, air being absolutely necessary for the support of inflammation. In examining the materials which issue from volcanos, even in the most violent eruptions, it appears very plain, that the furnace of the inflamed matters is not at any great depth, as they are similar to those found in mountains, disfigured only by the calcination, and the melting of the metallic parts which they contain; and to be convinced that the matters cast out by volcanos do not come from any great depth, we have only to consider of the height of the mountain, and judge of the immense force that would be necessary to cast up stones and minerals to the height of half a league; for Ætna, Hecla,

and many other volcanos have at least that elevation from the plains. Now it is perfectly well known that the action of fire is equal in every direction; it cannot therefore act upwards, with a force capable of throwing large stones half a league high, without an equal re-action downwards, and on the sides, and which re-action must very soon pierce and destroy the mountain on every side, because the materials which compose it are not more dense and firm than those thrown out; how then can it be imagined that the cavity, which must be considered as the type or cannon, could resist so great a force as would be necessary to raise those bodies to the mouth of the volcano? Besides, if this cavity was deeper, as the external orifice is not great, it would be impossible for so large a quantity of inflamed and liquid matter to issue out at once, without clashing against each other, and against the sides of the tube, and by passing through so long a space they would run the chance of being extinguished and hardened. We often see rivers of bitumen and melted sulphur, thrown out of the volcanos with stones and minerals, flow from the tops of the mountains into the plains; is it natural to imagine that matters so fluid, and so little able to resist

violent action, should be elevated from any great depth? All the observations that can be made on this subject will prove that the fire of the volcano is not far from the summit of the mountain, and that it never descends to the level of the plain.

This idea of volcanos does not, however, render it inconsistent that they are the cause of earthquakes, and that their shocks may be felt on the plains to very considerable distances; nor that one volcano may not communicate with another by means of subterraneous passages; but it is of the depth of the fire's confinement that we now speak, and which can only be at a small distance from the mouth of the volcano. It is not necessary to produce an earthquake on a plain, that the bottom of the volcano should be below the level of that plain; nor that there should be internal cavities filled with the same combustible matter, for a violent explosion, such as generally attends an eruption, may, like that of a powder magazine give so great a shock by its re-action, as to produce an earthquake that might be felt at a considerable distance.

I do not mean to say that there are no earthquakes produced by subterraneous fires, but

merely that there are some which proceed only from the explosion of volcanos. In confirmation of what has been advanced on this subject, it is certain that volcanos are seldom met with on plains; on the contrary, they are constantly found in the highest mountains, and their mouths at the very summit of them. If the internal fires of the volcanos extended below the plains, would not passages be opened in them during violent eruptions? In the first eruption would not these fires rather have pierced the plains, where, by comparison, the resistance must be infinitely weaker, than force their way through a mountain more than half a league in height.

The reason why volcanos appear alone in mountains, is, because much greater quantities of minerals, sulphur, and pyrites, are contained in mountains, and more exposed than in the plains; besides which, those high places are more subject to the impressions of air, and receive greater quantities of rain and damps, by which mineral substances are capable of being heated and fermented into an absolute state of inflammation.

In short, it has often been observed, that, after violent eruptions, the mountains have

shrunk and diminished in proportion to the quantity of matter which has been thrown out; another proof that the volcanos are not situated at the bottom of the mountain, but rather at no great distance from the summit itself.

In many places earthquakes have formed considerable hollows, and even separations in mountains; all other inequalities have been produced at the same time with the mountains themselves by the currents of the sea, for in every place where there has not been a violent convulsion, the strata of the mountains are parallel, and their angles exactly correspond. Those subterraneous caverns which have been produced by volcanos are easily to be distinguished from those formed by water; for the water, having washed away the sand and clay with which they are filled, leaves only the stones and rocks, and this is the origin of caverns upon hills; while those found upon the plains are commonly nothing but ancient pits and quarries, such as the salt quarries of Maestricht, the mines of Poland, &c. But natural caverns belong to mountains: they receive the water from the summit and its environs, from whence it issues over the surface wherever it can obtain a passage; and these are the sources of springs

and rivers, and whenever a cavern is filled by any part falling in, an inundation generally ensues.

From what we have related, it is easy to be seen how much subterraneous fires contribute to change the surface and internal part of the globe. This cause is sufficiently powerful to produce very great effects: but it is difficult to conceive how the winds should occasion any sensible alterations upon the earth. The sea appears to be their empire, and indeed, excepting the tides, nothing has so powerful an influence upon the ocean; even the flux and reflux move in an uniform manner, and their effects are regularly the same; but the action of the winds is capricious and violent; they sometimes rush on with such impetuosity, and agitate the sea with such violence, that from a calm, smooth, and tranquil plain, it becomes furrowed with waves rolling mountains high, and dashing themselves to pieces against the rocks and shores. The winds cause constant alterations on the surface of the sea, but the surface of the land, which has so solid an appearance, we should suppose would not be subject to similar effects; by experience, however, it is known that the winds raise mountains of

sand in Arabia and Africa; and that they cover plains with it; they frequently transport sand to great distances, and many miles into the sea, where they accumulate in such quantities as to form banks, downs, and even islands. It is also known that hurricanes are the scourge of the Antilles, Madagascar, and other countries, where they act with such fury, as to sweep away trees, plants, and animals, together with the soil which gave them subsistence: they cause rivers to ascend and descend, and produce new ones; they overthrow rocks and mountains; they make holes and gulphs on the earth, and entirely change the face of those unfortunate countries where they exist. Happily there are but few climates exposed to the impetuosity of those dreadful agitations of the air.

But the greatest and most general changes in the surface of the earth are produced by rains, floods, and torrents from the high lands. Their origins proceed from the vapours which the sun raises above the surface of the ocean, and which the wind transports through every climate. These vapours, which are sustained in the air, and conveyed at the will of the winds, are stopped in their progress by the tops of the hills which they encounter, where they

accumulate until they become clouds and fall in the form of rain, dew, or snow. These waters at first descend upon the plains without any fixed course, but by degrees hollow out a bed for themselves; by their natural bent they run to the bottom of mountains, and penetrating or dissolving the land easiest to divide, they carry earth and sand away with them, cut deep channels in the plains, form themselves into rivers, and open a passage into the sea, which constantly receives as much water from the land rivers as it loses by evaporation. The windings in the channels of rivers have sinuosities, whose angles are correspondent to each other, so that where the waves form a saliant angle on one side, the other has an exactly opposite one; and as hills and mountains, which may be considered as the banks of the vallies which separate them, have also sinuosities in corresponding angles, it seems to demonstrate that the vallies have been formed, by degrees, by the currents of the sea, in the same manner as the rivers have hollowed out their beds on the earth.

The waters which run on the surface of the earth, and support its verdure and fertility, are not perhaps one half of those which the vapours

produce; for there are many veins of water which sink to great depths in the internal part of the earth. In some places we are certain to meet with water by digging; in others, not any can be found. In almost all vallies and low grounds water is certain to be met with at moderate depths; but, on the contrary, in all high places it cannot be extracted from the bowels of the earth, but must be collected from the heavens. There are countries of great extent where a spring cannot be found, and where all the water which supplies the inhabitants and animals with drink is contained in pools and cisterns. In the east, especially in Arabia, Egypt, and Persia, wells are extremely scarce, and the people have been obliged to make reservoirs of a considerable extent to collect the waters as it falls from the heavens. These works, projected and executed from public necessity, are the most beautiful and magnificent monuments of the eastern nations; some of the reservoirs occupy a space of two square miles, and serve to fertilize whole provinces, by means of baths and small rivulets that let it out on every side. But in low countries, where the greatest rivers flow, we cannot dig far from the surface, without

meeting with water, and in fields situate in the environs of rivers it is often obtained by a few strokes with a pick-axe.

The water, found in such quantities in low grounds, comes principally from the neighbouring hills and eminences; at the time of great rains or sudden melting of snow, a part of the water flows on the surface, but most of it penetrates through the small cracks and crevices it finds in the earth and rocks. This water springs up again to the surface wherever it can find vent; but it often filters through the sand until it comes to a bottom of clay or solid earth, where it forms subterraneous lakes, rivulets, and perhaps rivers, whose courses are entirely unknown; they must, however, follow the general laws of nature, and constantly flow from the higher grounds to the lower, and consequently these subterraneous waters must, in the end, fall into the sea, or collect in some low place, either on the surface or in the interior part of the earth; for there are several lakes into which no rivers enter, nor from which there are not any issue; and a much greater number, which do not receive any considerable river, that are the sources of the greatest rivers

on earth; such as the lake of St. Laurence; the lake Chiamè, from whence spring two great rivers that water the kingdoms of Asam and Pegu; the lake of Assiniboil in America; those of Ozera in Muscovy, that give rise to the river Irtis, and a great number of others. These lakes, it is evident, must be produced by the waters from the high lands passing through subterraneous passages, and collecting in the lowest places. Some indeed have asserted that lakes are to be found on the summit of the highest mountains; but to this no credit can be given, for those found on the Alps, and other elevated places, are all surrounded by much more lofty mountains, and derive their origin from the waters which run down the sides, or are filtered through those eminences in the same manner as the lakes in the plains obtain their sources from the neighbouring hills which overtop them.

It is apparent, therefore, that lakes have existence in the bowels of the earth, especially under large plains and extensive vallies. Mountains, hills, and all eminences have either a perpendicular or inclined situation, and are exposed on all sides; the waters which fall on

their summits, after having penetrated into the earth, cannot fail, from the declivity of the ground, of finding issue in many places, and breaking in forms out of springs and fountains, and consequently there will be little, if any water, remain in the mountains. On the contrary, in plains, as the water which filters through the earth can find no vent, it must collect in subterraneous caverns, or be dispersed and divided among sand and gravel. It is these waters which are so universally diffused through low grounds. The bottom of a pit or well is nothing else but a kind of bason into which the waters that issue from the adjoining lands insinuate themselves, at first falling drop by drop, but afterwards, as the passages are opened, it receives supplies from greater distances, and then continually runs in little streams or rills; from which circumstance, although we can find water in any part of a plain, yet we can obtain a supply but for a certain number of wells, proportionate to the quantity of water dispersed, or rather to the extent of the higher lands from whence they come.

It is unnecessary to dig below the level of the river to find water; it is generally met with

at much less depths, and there is no appearance that waters of rivers filter far through the earth. The origin of waters found in the earth below the level of rivers is not to be attributed to them; for in rivers or torrents which are dried up, or whose courses have been turned, we find no greater quantity of water by digging in their beds than in the neighbouring lands at an equal depth.

A piece of land of five or six feet in thickness is sufficient to contain water, and prevent it from escaping; and I have often observed that the banks of brooks and pools are not sensibly wet at six inches distance from the water.

It is true that the extent of the filtration is in proportion as the soil is more or less penetrable; but if we examine the standing pools with sandy bottoms, we shall perceive the water confined in the small compass it had hollowed itself, and the moisture spread but a very few inches; even in vegetable earth it has no great extent, which must be more porous than sand or hard soil. It is a certain fact, that in a garden we may almost inundate one bed without those nearly adjoining feeling

any moisture from it[65:A]. I have examined pieces of garden ground, eight or ten feet thick, which had not been stirred for many years, and whose surface was nearly level, and found that the rain water never penetrated deeper than three or four feet; and on turning it up in the spring, after a wet winter, I found it as dry as when first heaped together.

I made the same observation on earth which had laid in ridges two hundred years; below three or four feet it was as dry as dust; from which it is plain that water does not extend so far by filtration as has been generally imagined.

By this means, therefore, the internal part of the earth can be supplied with a very small part; but water by its own weight descends from the surface to the greatest depths; it sinks through natural conduits, or penetrates small passages for itself; it follows the roots of trees, the cracks in rocks, the interstices in the earth, and divides and extends on all sides into an infinity of small branches and rills, always

descending until its passage is opposed by clay or some solid body, where it continues collecting, and at length breaks out in form of springs upon the surface.

It would be very difficult to make an exact calculation of the quantity of subterraneous waters which have no apparent vent. Many have pretended that it greatly surpasses all the waters that are on the surface of the earth.

Without mentioning those who have advanced that the interior part of the globe is entirely filled with water, there are some who believe there are an infinity of floods, rivulets, and lakes in the bowels of the earth. But this opinion does not seem to be properly founded, and it is more probable that the quantity of subterraneous water, which never appears on the surface, is not very considerable; for if these subterraneous rivers are so very numerous, why do we never see any of their mouths forcing their way through the surface? Besides, rivers, and all running waters, produce great alterations on the surface of the earth; they transport the soil, wear away the most solid rocks, and displace all matters which oppose

their passage. It would certainly be the same in subterraneous rivers; the same effects would be produced; but no such alterations have ever as yet been observed; the different strata remains parallel, and every where preserves its original position; and it is but in a very few places that any considerable subterraneous veins of water have been discovered. Thus water in the internal part of the earth, though great, acts but in a small degree, as it is divided in an infinity of little streams, and retained by a number of obstacles; and being so generally dispersed, it gives rise to many substances totally different from primitive matters, both in form and organization.

From all these observations we may fairly conclude, that it is the continual motion of the flux and reflux of the sea which has produced mountains, vallies, and other inequalities on the surface of the earth; that it is the currents of the ocean which have hollowed vallies, raised hills, and given them corresponding directions; that it is those waters of the sea which, by transporting earth, &c. and depositing them in horizontal layers, have formed the parallel strata; that it is the waters from heaven,

which by degrees destroy the effects of the sea, by continually lowering the summit of mountains, filling up vallies, and stopping the mouths of gulphs and rivers, and which, by bringing all to a level, will, in the course of time, return this earth to the sea, which, by its natural operations, will again form new continents, containing vallies and mountains exactly similar to those which we at present inhabit.

FOOTNOTES:

[25:A] Particularly Scotland and Ireland.

[65:A] These facts are so easily demonstrated, that the smallest observation will prove their veracity.

PROOF
OF
THE THEORY OF THE EARTH.

ARTICLE I.
ON THE FORMATION OF THE PLANETS.

Our subject being Natural History, we would willingly dispense with astronomical observations; but as the nature of the earth is so closely connected with the heavenly bodies, and such observations being calculated to illustrate more fully what has been said, it is necessary to give some general ideas of the formation, motion, figure of the earth and other planets.

The earth is a globe of about three thousand leagues diameter; it is situate one thousand millions of leagues from the sun, around which it makes its revolution in three hundred and sixty-five days. This revolution is the

result of two forces; the one may be considered as an impulse from right to left, or from left to right, and the other an attraction from above downwards, or beneath upwards, to a common centre. The direction of these two forces, and their quantities, are so nicely combined and proportioned, that they produce an almost uniform motion in an ellipse, very near to a circle. Like the other planets the earth is opaque, it throws out a shadow; it receives and reflects the light of the sun, round which it revolves in a space of time proportioned to its relative distance and density. It also turns round its own axis once in twenty-four hours, and its axis is inclined 66-1/4 degrees on the plane of the orbit. Its figure is spheroidical, the two axes of which differ about 160th part from each other, and the smallest axis is that round which the revolution is made.

These are the principal phenomena of the earth, the result of discoveries made by means of geometry, astronomy, and navigation. We shall not here enter into the detail of the proofs and observations by which those facts have been ascertained, but only make a few remarks to clear up what is still doubtful, and at the

same time give our ideas respecting the formation of the planets, and the different changes thro' which it is possible they have passed before they arrived at the state we at present see them.

There have been so many systems and hypotheses framed upon the formation of the terrestrial globe, and the changes which it has undergone, that we may presume to add our conjectures to those who have written upon the subject, especially as we mean to support them with a greater degree of probability than has hitherto been done: and we are the more inclined to deliver our opinion upon this subject, from the hope that we shall enable the reader to pronounce on the difference between an hypothesis drawn from possibilities, and a theory founded in facts; between a system, such as we are here about to present, on the formation and original state of the earth, and a physical history of its real condition, which has been given in the preceding discourse.

Galileo having found the laws of falling bodies, and Kepler having observed that the area described by the principal planets in moving round the sun, and those of the satellites round the planets to which they belong, are proportionable to the time of their revolutions,

and that such periods were also in proportion to the square roots of the cubes of their distances from the sun, or principal planets. Newton found that the force which caused heavy bodies to fall on the surface of the earth, extended to the moon, and retained it in its orbit; that this force diminished in the same proportion as the square of the distance increased, and consequently that the moon is attracted by the earth; that the earth and planets are attracted by the sun; and that in general all bodies which revolve round a centre, and describe areas proportioned to the times of their revolution, are attracted towards that point. This power, known by the name of GRAVITY, is therefore diffused throughout all matter; planets, comets, the sun, the earth, and all nature, is subject to its laws, and it serves as a basis to the general harmony which reigns in the universe. Nothing is better proved in physics than the actual existence of this power in every material substance. Observation has confirmed the effects of this power, and geometrical calculations have determined the quantity and relations of it.

This general cause being known, the effects would easily be deduced from it, if the action

of the powers which produce it were not too complicated. A single moment's reflection upon the solar system will fully demonstrate the difficulties that have attended this subject; the principal planets are attracted by the sun, and the sun by the planets; the satellites are also attracted by their principal planets, and each planet attracts all the rest, and is attracted by them. All these actions and reactions vary according to the quantities of matter and the distances, and produce great inequalities and irregularities. How is so great a number of connections to be combined and estimated? It appears almost impossible in such a crowd of objects to follow any particular one; nevertheless those difficulties have been surmounted, and calculation has confirmed the suppositions of them, each observation is become a new demonstration, and the systematic order of the universe is laid open to the eyes of all those who can distinguish truth from error.

We feel some little stop, by the force of impulsion remaining unknown; but this, however, does not by any means affect the general theory. We evidently see the force of attraction always draws the planets towards

the sun, they would fall in a perpendicular line, on that planet, if they were not repelled by some other power that obliges them to move in a straight line, and which impulsive force would compel them to fly off the tangents of their respective orbits, if the force of attraction ceased one moment. The force of impulsion was certainly communicated to the planets by the hand of the Almighty, when he gave motion to the universe; but we ought as much as possible to abstain in physics from having recourse to supernatural causes; and it appears that a probable reason may be given for this impulsive force, perfectly accordant with the law of mechanics, and not by any means more astonishing than the changes and revolutions which may and must happen in the universe.

The sphere of the sun's attraction does not confine itself to the orbs of the planets, but extends to a remote distance, always decreasing in the same ratio as the square of the distance increases; it is demonstrated that the comets which are lost to our sight, in the regions of the sky, obey this power, and by it their motions, like that of the planets, are regulated. All these stars, whose tracts are so different,

move round the sun, and describe areas proportioned to the time; the planets in ellipses more or less approaching a circle, and the comets in narrow ellipses of a great extent. Comets and planets move, therefore, by virtue of the force of attraction and impulsion, which continually acting at one time obliges them to describe these courses; but it must be remarked that comets pass over the solar system in all directions, and that the inclinations of their orbits are very different, insomuch that, although subject like the planets to the force of attraction, they have nothing in common with respect to their progressive or impulsive motions, but appear in this respect independent of each other: the planets, on the contrary, move round the sun in the same direction, and almost in the same plane, never exceeding 7-1/2 degrees of inclination in their planes, the most distant from their orbits. This conformity of position and direction in the motion of the planets, necessarily implies that their impulsive force has been communicated to them by one and the same cause.

May it not be imagined, with some degree of probability, that a comet falling into the body of the sun, will displace and separate some

parts from the surface, and communicate to them a motion of impulsion, insomuch that the planets may formerly have belonged to the body of the sun, and been detached therefrom by an impulsive force, and which they still preserve.

This supposition appears to be at least as well founded as the opinion of Leibnitz, who supposes that the earth and planets had formerly been suns; and his system, of which an account will be given in the fifth article, would have been more comprehensive and more agreeable to probability, if he had raised himself to this idea. We agree with him in thinking that this effect was produced at the time when Moses said that God divided light from darkness; for, according to Leibnitz, light was divided from darkness when the planets were extinguished; but in our supposition there was a real physical separation, since the opaque bodies of the planets were divided from the luminous matter which composes the sun.

This idea of the cause of the impulsive force of the planets will be found much less objectionable, when an estimation is made of the analogies and degrees of probability, by

which it may be supported. In the first place, the motion of the planets are in the same direction, from West to East, and therefore, according to calculation, it is sixty-four to one that such would not have been the case, if they had not been indebted to the same cause for their impulsive forces.

This, probably, will be considerably augmented by the second analogy, viz. that the inclination of the planes of the orbits do not exceed 7-1/2 degrees; for, by comparing the spaces, we shall find there is twenty-four to one, that two planets are found in their most distant places at the same time, and consequently ⁵, or 7,692,624 to one, that all six would by chance be thus placed; or, what amounts to the same, there is a great degree of probability that the planets have been impressed with one common moving force, and which has given them this position. But what can have bestowed this common impulsive motion, but the force and direction of the bodies by which it was originally communicated? It may therefore be concluded, with great probability, that the planets received their impulsive motion by one single stroke. This likelihood, which is almost equivalent to a

certainty, being established, I seek to know what moving bodies could produce this effect, and I find nothing but comets capable of communicating a motion to such vast bodies.

By examining the course of comets, we shall be easily persuaded, that it is almost necessary for some of them occasionally to fall into the sun. That of 1680 approached so near, that at its perihelium it was not more distant from the sun than a sixteenth part of its diameter, and if it returns, as there is every appearance it will, in 2255, it may then possibly fall into the sun; that must depend on the rencounters it will meet with in its road, and of the retardment it suffers in passing through the atmosphere of the sun[78:A].

We may, therefore, presume with the great Newton, that comets sometimes fall into the sun; but this fall may be made in different directions. If they fall perpendicular, or in a direction not very oblique, they will remain in the sun, and serve for food to the fire which that luminary consumes, and the motion of impulsion which they will have communicated to the sun, will produce no other effect than that of removing it more or less, according as the mass of the comet will be more or less

considerable; but if the fall of the comet is in a very oblique direction, which will most frequently happen, then the comet will only graze the surface of the sun, or slightly furrow it; and in this case it may drive out some parts of matter to which it will communicate a common motion of impulsion, and these parts so forced out of the body of the sun, and even the comet itself, may then become planets, and turn round this luminary in the same direction, and in almost the same plane. We might perhaps calculate what quantity of matter, velocity, and direction a comet should have, to impel from the sun an equal quantity of matter to that which the six planets and their satellites contain; but it will be sufficient to observe here, that all the planets, with their satellites, do not make the 650th part of the mass of the sun,[79:A] because the density of the large planets, Saturn and Jupiter, is less than that of the sun; and although the earth be four times, and the moon near five times more dense than the sun, they are nevertheless but as atoms in comparison with his extensive body.

However inconsiderable the 650th part may be, yet it certainly at first appears to require a very powerful comet to separate even that much

from the body of the sun; but if we reflect on the prodigious velocity of comets in their perihelion, a velocity so much the greater as they approach nearer the sun; if, besides, we pay attention to the density and solidity of the matter of which they must be composed, to suffer, without being destroyed, the inconceivable heat they endure; and consider the bright and solid light which shines through their dark and immense atmospheres, which surround, and must obscure them, it cannot be doubted that the comets are composed of extremely solid and dense matters, and that they contain a greater quantity of matter in a small compass; that consequently a comet of no extraordinary bulk may have sufficient weight and velocity to displace the sun, and give a projectile motion to a quantity of matter, equal to the 650th part of the mass of this luminary. This perfectly agrees with what is known concerning the density of planets, which always decreases as their distance from the sun is increased, they having less heat to support; so that Saturn is less dense than Jupiter, and Jupiter much less than the earth; therefore if the density of the planets be, as Newton asserts, proportionable to the quantity

of heat which they have to support, Mercury will be seven times more dense than the earth, and twenty-eight times denser than the sun; and the comet of 1680 would be 28,000 times denser than the earth, or 112,000 times denser than the sun, and by supposing it as large as the earth, it would contain nearly an equal quantity of matter to the ninth part of the sun, or by giving it only the 100th part of the size of the earth, its mass would still be equal to the 900th part of the sun. From whence it is easy to conclude, that such a body, though it would be but a small comet, might separate and drive off from the sun a 900th or a 650th part, particularly if we attend to the immense velocity with which comets move when they pass in the vicinity of the sun.

Besides this, the conformity between the density of the matter of the planets, that of the sun deserves some attention. It is well known, that, both on and near the surface of the earth, there are some matters 14 or 1500 times denser than others. The densities of gold and air are nearly in this relation. But the internal parts of the earth and planets are composed of a more uniform matter, whose

comparative density varies much less; and the conformity in the density of the planets and that of the sun is such, that of 650 parts which compose the whole of the matter of the planets, there are more than 640 of the same density as the matter of the sun, and only ten parts out of these 650 which are of a greater density, for Saturn and Jupiter are nearly of the same density as the sun, and the quantity of matter which these planets contain, is at least 64 times greater than that of the four inferior planets, Mars, the Earth, Venus, and Mercury. We must therefore admit, that the matter of which the planets are generally composed is nearly the same as that of the sun, and that consequently the one may have been separated from the other.

But it may be said, if the comet, by falling obliquely on the sun, drove off the matter which compose the planets, they, instead of describing circles of which the sun is the centre, would, on the contrary, at each revolution, have returned to the same point from whence they departed, as every projectile would which might be thrown off with sufficient force from the surface of the earth, to oblige it to turn perpetually: for it is easy to demonstrate that such,

in that instance, would be the case, and therefore that the projection of the planets from the sun cannot be attributed to the impulsion of a comet.

To this I reply, that the matter which composes the planets did not come from the sun, in ready formed globes, but in the form of torrents, the motion of the anterior parts of which were accelerated by that of the posterior; and that the attraction of the anterior parts also accelerated the motion of the posterior, and that this acceleration produced by one or other of these causes, or perhaps by both, might be so great as to change the original direction of the motion occasioned by the impulse of the comet, from which cause a motion has resulted, such as we at present observe in the planets; especially when it is considered the sun is displaced from its station by the shock of the comet. An example will render this more reasonable; let us suppose, that from the top of a mountain a musket ball is discharged, and that the strength of the powder was sufficient to send it beyond the semi-diameter of the earth, it is certain that this ball would pass round the earth, and at each revolution return to the spot from whence it had been discharged:

but, if instead of a musket-ball, we suppose a rocket had been discharged, wherein the action of the fire being durable, would greatly accelerate the motion of impulsion; this rocket, or rather the cartouch which contained it, would not return to the same place like the musket-ball, but would describe an orbit, whose perigee would be much farther distant from the earth, as the force of acceleration would be greater, and have changed the first direction.

Thus, provided there had been any acceleration in the motion of impulsion communicated to the torrent of matter by the fall of the comet, it is probable that the planets formed in this torrent, acquired the motion which we know they have in the circles and ellipsis of which the sun is the centre and focus.

The manner in which the great eruptions of volcanos are made, may afford us an idea of this acceleration of motion. It has been remarked that when Vesuvius begins to roar and eject the inflamed matter it contains, the first cloud has but a small degree of velocity, but which is soon accelerated by the impulse of the second; the second by the action of a third, and so on, until the heavy mass of bitumen,

sulphur, cinders, melted metal, and huge stones, appear like massive clouds, and although they succeed each other nearly in the same directions, yet they greatly change that of the first, and drive it far beyond what it would have reached of itself.

In answer to this objection, it may be further observed, that the sun having been struck by the comet, received a degree of motion by the impulse, which displaced it from its former situation; and that although this motion of the sun is at present too little sensible for the notice of astronomers, nevertheless it may still exist, and the sun describe a curve round the centre of gravity of the whole system and if this is so, as I presume it is, we see perfectly that the planets, instead of returning near the sun at each revolution, will, on the contrary, have described orbits, the points of the perihelion of which will be as far distant from the sun, as it is itself from the place it originally occupied.

It may also be said, that if this acceleration of motion is made in the same direction, no change in the perihelion will be produced: but can it be thought that in a torrent, the particles of which succeed each other, there has

been no change of direction; it is, on the contrary, very probable that a considerable change did take place, sufficient to cause the planets to move in the course they at present occupy.

It may be further urged, that if the sun had been displaced by the shock of a comet, it would move uniformly, and that hence this motion being common to the whole system, no alteration was necessary; but might not the sun before the shock have had a motion round the centre of the cometry system, to which primitive motion the stroke of the comet may have added or diminished? and would not that fully account for the actual motion of the planets?

If these suppositions are not admitted, may it not be presumed, that in the stroke of the comet against the sun, there was an elastic force which raised the torrent above the surface of the sun, instead of directly impelling it? which alone would be sufficient to remove the perihelion, and give the planets the motion they have retained. This supposition is not without probability, for the matter of the sun may possibly be very elastic, since light, the only part of it we are acquainted with, seems,

by its effects, to be perfectly so. I own that I cannot say whether it is by the one or the other of these reasons, that the direction of the first motion of the impulse of the planets has changed, but they suffice to shew that such an alteration is not only possible but even probable, and that is sufficient for my purpose.

But, without dwelling any longer on the objections which might be made, I shall pursue the subject, and draw the fair conclusions on the proofs which analogies might furnish in favour of my hypothesis: let us, therefore, first see what might happen when these planets, and particularly the earth, received their impulsive motion, and in what state they were after having been separated from the sun. The comet having, by a single stroke, communicated a projectile motion to a quantity of matter equal to the 650th part of the sun's mass, the light particles would of course separate from the dense, and form, by their mutual attraction, globes of different densities: Saturn being composed of the most gross and light parts, would be the most remote from the sun: Jupiter being more dense than Saturn, would be less distant, and so on. The larger and least solid planets are the most remote, because they

received an impulsive motion stronger than the smallest, and more dense: for, the force of impulsion communicating itself according to the surface, the same stroke would have moved the grosser and lighter parts of the matter of the sun with more velocity than the smallest and more weighty; a separation therefore will be made of the dense parts of different degrees, so that the density of the sun being equal to 100, that of Saturn will be equal to 67, that of Jupiter to 94-1/2, that of Mars to 200, that of the Earth to 400, that of Venus to 800, and that of Mercury to 2800. But the force of attraction not communicating like that of impulsion, according to the surface, but acting on the contrary on all parts of the mass, it will have checked the densest portions of matter; and it is for this reason that the densest planets are the nighest the sun, and turn round that planet with greater rapidity than the less dense planets, which are also the most remote.

Jupiter and Saturn, which are the largest and principal planets of the solar system, have retained the relation between their density and impulsive motions, in the most exact proportions; the density of Saturn is to that of Jupiter as 67 to 94-1/2 and their velocities are

nearly as 88-2/3 to 120-1/72, or as 67 to 90-11/16; it is seldom that pure conjectures can draw such exact relations. It is true, that by following this relation between the velocity and density of planets, the density of the earth ought to be only as 206-7/18, and not 400, which is its real density; from hence it may be conceived, that our globe was formerly less dense than it is at present. With respect to the other planets, Mars, Venus, and Mercury, as their densities are known only by conjecture, we cannot be certain whether this circumstance will destroy or confirm our hypothesis. The opinion of Newton is, that density is so much the greater, as the heat to which the planet is exposed is the stronger; and it is on this idea that we have just said that Mars is one time less dense than the Earth, Venus one time, Mercury seven times, and the comet in 1680, 28,000 times denser than the earth: but this proportion between the density of the planets and the heat which they sustain, seems not well founded, when we consider Saturn and Jupiter, which are the principal objects; for, according to this relation between the density and heat, the density of Saturn would be about 4-7/18, and that of Jupiter as 14-17/22, instead of 67 and

94-1/2, a difference too great to be admitted, and must destroy the principles upon which it was founded. Thus, notwithstanding the confidence which the conjectures of Newton merit, I can but think that the density of the planets has more relation with their velocity than with the degree of heat to which they are exposed. This is only a final cause, and the other a physical relation, the preciseness of which is remarkable in Jupiter and Saturn: it is nevertheless true, that the density of the earth, instead of being 206-7/8, is found to be 400, and that consequently the terrestrial globe must be condensed in this ratio of 206-7/8 to 400.

But have not the condensations of the planets some relation with the quantity of the heat of the sun which they sustain? If so, Saturn, which is the most distant from that luminary, will have suffered little or no condensation; and Jupiter will be condensed from 90-11/16 to 94-1/2. Now the heat of the sun in Jupiter being to that of the sun upon the earth as 14-17/22 are to 400, the condensations ought to be in the same proportion. For instance, if Jupiter be condensed, as 90-11/16 to 94-1/2, and the earth had been placed in his orbit, it would have been condensed from 206-7/8 to 215-990/1451, but the earth

being nearer the sun, and receiving a heat, whose relation to that which Jupiter receives is from 400 to 14-17/22, the quantity of condensation it would have experienced on the orbit of Jupiter by the proportion of 400 to 14-17/22, which gives nearly 234-1/3 for the quantity which the earth would be condensed. Its density was 206-7/8, by adding the quantity of its acquired condensation, we find 400-7/8 for its actual density, which nearly approaches the real density 400, determined to be so by the parallax of the moon. As to other planets, I do not here pretend to give exact proportions, but only approximations, to point out that their densities have a strong relation to their velocity in their respective orbits.

The comet, therefore, by its oblique fall upon the surface of the sun, having driven therefrom a quantity of matter equal to the 650th part of its whole mass; this matter, which must be considered in a liquid state, will at first have formed a torrent, the grosser and less dense parts of which will have been driven the farthest, and the smaller and more dense, having received only the like impulsion, will remain nearest its source; the force of the sun's attraction would inevitably act upon all the

parts detached from him, and constrain them to circulate around his body, and at the same time the mutual attraction of the particles of matter would form themselves into globes at different distances from the sun, the nearest of which necessarily moving with greater rapidity in their orbits than those at a distance.

But another objection may be started, and it may be said, if the matter which composes the planets had been separated from the sun, they, like him, would have been burning and luminous bodies, not cold and opaque, for nothing resembles a globe of fire less than a globe of earth and water; and by comparison, the matter of the earth and planets is perfectly different from that of the sun?

To this it may be answered, that in the separation the matter changed its form, and the light or fire was extinguished by the stroke which caused this motion of impulsion. Besides, may it not be supposed that if the sun, or a burning star, moved with such velocity as the planet, that the fire would soon be extinguished; and that is the reason why all luminous stars are fixed, and that those stars which are called new, and which have probably

changed places, are frequently extinguished and lost? This remark is somewhat confirmed by what has been observed in comets; they must burn to the centre when they pass to their perihelium: nevertheless they do not become luminous themselves, they only exhale burning vapours, of which they leave a considerable part behind them in their course.

I own, that in a medium where there is very little or no resistance, fire may subsist and suffer a very great motion without being extinguished: I also own, that what I have just said extends only to the stars which totally disappear, and not to those which have periodical returns, and appear and disappear alternately without changing place in the heavens. The phenomena of these stars has been explained in a very satisfactory manner by M. de Maupertuis, in his discourse on the figures of the planets. But the stars which appear and afterwards disappear entirely, must certainly have been extinguished, either by the velocity of their motion, or some other cause. We have not a single example of one luminous star revolving round another; and among the number of planets which compose our system, and

which move round the sun with more or less rapidity, there is not one luminous of itself.

It may also be added, that fire cannot subsist so long in the small as in large masses, and that the planets must have burnt for some time after they were separated from the sun, but were at length extinguished for want of combustible matter, as probably would be the sun itself, and for the same reason; but in a length of time as far beyond that which extinguished the planets, as it exceeds in quantity of matter. Be this as it may, the matter of which the planets are formed being separated from the sun, by the stroke of a comet, that appears a sufficient reason for the extinction of their fires.

The earth and planets at the time of their quitting the sun, were in a state of total liquid fire; in this state they remained only as long as the violence of the heat which had produced it; and which heat necessarily underwent a gradual decay: it was in this state of fluidity that they took their circular forms, and that their regular motions raised the parts of their equators, and lowered their poles. This figure, which agrees so perfectly with the laws of hydrostatics, I am of opinion with Leibnitz,

necessarily supposes that the earth and planets have been in a state of fluidity, caused by fire, and that the internal part of the earth must be a vitrifiable matter, of which sand, granite, &c. are the fragments and scoria.

It may, therefore, with some probability, be thought that the planets appertained to the sun, that they were separated by a single stroke, which gave to them a motion of impulsion, and that their position at different distances from the sun proceeds only from their different densities. It now only remains, to complete this theory, to explain the diurnal motion of the planets, and the formation or the satellites; but this, far from adding difficulties to my hypothesis, seems, on the contrary, to confirm it.

For the diurnal motion, or rotation, depends solely on the obliquity of the stroke, an oblique impulse therefore on the surface of a body will necessarily give it a rotative motion; this motion will be equal and always the same, if the body which receives it is homogeneous, and it will be unequal if the body is composed of heterogeneous parts, or of different densities; hence we may conclude that in all the planets the matter is homogeneous, since their diurnal

motions are equal, and regularly performed in the same period of time. Another proof that the separation of the dense or less dense parts were originally from the sun.

But the obliquity of the stroke might be such, as to separate from the body of the principal planet a small part of matter, which would of course continue to move in the same direction; these parts would be united, according to their densities, at different distances from the planet, by the force of their mutual attraction, and at the same time follow its course round the sun, by revolving about the body of the planet, nearly in the plane of its orbit. It is plain, that those small parts so separated are the satellites: thus the formation, position, and direction of the motions of the satellites perfectly agree with our theory; for they have all the same motion in concentrical circles round their principal planet; their motion is in the same direction, and that nearly in the plane of their orbits. All these effects, which are common to them, and which depend on an impulsive force, can proceed only from one common cause, which is, impulsive motion, communicated to them by one and the same oblique stroke.

What we have just said on the cause of the motion and formation of the satellites, will acquire more probability, if we consider all the circumstances of the phenomena. The planets which turn the swiftest on their axis, are those which have satellites. The earth turns quicker than Mars in the relation of about 24 to 15; the earth has a satellite, but Mars has none. Jupiter, whose rapidity round its axis is five to six hundred times greater than that of the earth, has four satellites, and there is a great appearance that Saturn, which has five, and a ring, turns still more quickly than Jupiter.

It may even be conjectured with some foundation, that the ring of Saturn is parallel to the equator of the planet, so that the plane of the equator of the ring, and that of Saturn, are nearly the same; for by supposing, according to the preceding theory, that the obliquity of the stroke by which Saturn has been set in motion was very great, the velocity around the axis will, at first, have been in proportion as the centrifugal force exceeds that of gravity, and there will be detached from its equator and neighbouring parts, a considerable quantity of

matter, which will necessarily have taken the figure of a ring, whose plane must be nearly the same as that of the equator of the planet; and this quantity of matter having been detached from the vicinity of the equator of Saturn, must have lowered the equator of that planet, which causes that, notwithstanding its rapidity, the diameters of Saturn cannot be so unequal as those of Jupiter, which differ from each other more than an eleventh part.

However great the probability of what I have advanced on the formation of the planets and their satellites may appear to me, yet, every man has his particular measurement, to estimate probabilities of this nature; and as this measurement depends on the strength of the understanding to combine more or less distant relations, I do not pretend to convince the incredulous. I have not only thought it my duty to offer these ideas, because they appear to me reasonable, and calculated to clear up a subject, on which, however important, nothing has hitherto been written, but because the impulsive motion in the planets enter at least as one half of the composition of the universe, which gravity alone cannot unfold. I

shall only add the following questions to those who are inclined to deny the possibility of my system.

1. Is it not natural to imagine, that a body in motion has received that motion by the stroke of another body?

2. Is it not very probable, that when many bodies move in the same direction, that they have received this direction by one single stroke, or by many strokes directed in the same manner?

3. Is it not more probable that when many bodies have the same direction in their motion, and are placed in the same plane, that they received this direction and this position by one and the same stroke, rather than by a number?

4. At the time a body is put in motion by the force of impulsion, is it not probable that it receives it obliquely, and, consequently, is obliged to turn on its axis so much the quicker, as the obliquity of the stroke will have been greater? If these questions should not appear unreasonable, the theory, of which we have presented the outlines, will cease to appear an absurdity.

Let us now pass on to something which more nearly concerns us, and examine the

figure of the earth, on which so many researches and such great observations have been made. The earth being, as it appears by the equality of its diurnal motion and the constancy of the inclination of its axis, composed of homogeneous parts, which attract each other in proportion to their quantity of matter, it would necessarily have taken the figure of a globe perfectly spherical, if the motion of impulsation had been given it in a perpendicular direction to the surface; but this stroke having been obliquely given, the earth turned on its axis at the moment it took its form; and from the combination of this impulsive force, the attraction of the parts, there has resulted a spheroid figure, more elevated under the great circle of rotation, and lower at the two extremities of the axis, and this because the action of the centrifugal force proceeding from the diurnal rotation must diminish the action of gravity. Thus, the earth being homogeneous, and having received a rotative motion, necessarily took a spheroidical figure, the two axes of which differ a 230th part from each other. This may be clearly demonstrated, and does not depend on any hypothesis whatever. The laws of gravity are perfectly

known, and we cannot doubt that bodies attract each other in a direct ratio of their masses, and in an inverted ratio, at the squares of their distances; so likewise we cannot doubt, that the general action of any body is not composed of all the particular actions of its parts. Thus each part of matter mutually attracts in a direct ratio of its mass and an inverted ratio of its distance, and from all these attractions there results a sphere when there is no rotatory motion, and a spheroid when there is one. This spheroid is longer or shorter at the two extremities of the axis of rotation, in proportion to the velocity of its diurnal motion, and the earth has then, by virtue of its rotative velocity, and of the mutual attraction of all its parts, the figure of a spheroid, the two axes of which are as 229 to 230 to one another.

Thus, by its original constituent, by its homogeneousness, and independent of every hypothesis from the direction of gravity, the earth has taken this figure of a spheroid at its formation, and agreeable to mechanical laws: its equatorial diameter was raised about 6-1/2 leagues higher than under the poles.

I shall dwell on this article, because there are still geometricians who think that the figure of the earth depends upon theory, and this from a system of philosophy they have embraced, and from a supposed direction of gravity. The first thing we have to demonstrate is, the mutual attraction of every part of matter, and the second the homogeneousness of the terrestrial globe; if we clearly prove, that these two circumstances are really so, there will no longer be any hypothesis to be made on the direction of gravity: the earth will necessarily have the figure Newton decided in favour of, and every other figure given to it by virtue of vortexes or other hypotheses, will not be able to subsist.

It cannot be doubted, that it is the force of gravity which retains the planets in their orbits; the satellites of Saturn gravitate towards Saturn, those of Jupiter towards Jupiter, the Moon gravitates towards the Earth: and Saturn, Jupiter, Mars, the Earth, Venus, and Mercury, gravitate towards the Sun: so likewise Saturn and Jupiter gravitate towards their satellites, the Earth gravitates towards the Moon, and the Sun towards the whole of the

planets. Gravitation is therefore general and mutual in all the planetary system, for action cannot be exercised without a re-action; all the planets, therefore, act mutually one on the other. This mutual attraction serves as a foundation to the laws of their motion, and is demonstrated to exist by its effects. When Saturn and Jupiter are in conjunction, they act one on the other, and this attraction produces an irregularity in their motion round the Sun. It is the same with the Earth and the Moon, they also mutually attract each other; but the irregularities of the motion of the Moon, proceeds from the attraction of the Sun, so that the Earth, the Sun, and the Moon, mutually act one on the other. Now this mutual attraction of the planets, when the distances are equal, is proportional to their quantity of matter, and the same force of gravity which causes heavy matter to fall on the surface of the Earth, and which extends to the Moon, is also proportional to the quantity of matter; therefore the total gravity of a planet is composed of the gravity of each of its parts; from whence all the parts of the matter, either in the Earth or in the planets, mutually attract each other and the Earth, by its rotation round its own

axis, has necessarily taken the figure of a spheroid, the axes of which are as 229 to 230. The direction of the weight must be perpendicular to the Earth's surface; consequently no hypothesis, drawn from the direction of gravity, can be sustained, unless the general attraction of the parts of matter be denied; but the existence of this mutual attraction is demonstrated by observations, and the experiment of pendulums prove, that its extension is general; therefore we cannot support an hypothesis on the direction of gravity without going against experience and reason.

Let us now proceed to examine whether the matter of which the terrestrial globe is composed be homogeneous. I admit, that if it is supposed the globe is more dense in some parts than in others, the direction of gravity must be different from what we have just assigned, and that the figure of the Earth would also differ agreeable to those suppositions. But what reason have we to make these suppositions? Why, for example, should we suppose that the parts near the centre are denser than those which are more remote? Are not all the particles which compose the globe collected together by their mutual attraction?

hence, each particle is a centre, and there is no reason to believe, that the parts which surround the centre are denser than those which are about any other point. Besides, if one considerable part of the globe was denser than another, the axis of rotation would be found near the dense parts, and an inequality would ensue in the diurnal revolution; we should remark an inequality in the apparent motion of the fixed stars; they would appear to move more quick or slow in the zenith, or horizon, according as we should be placed on the denser or lighter parts of the earth; and the axis of the globe no longer passing through the centre of gravity, would also very sensibly change its position: but nothing like this ever happens; on the contrary, the diurnal motion of the earth is equal and uniform. At all parts of the Earth's surface, the stars appear to move with the same velocity at all heights, and if there be any rotation in its axis, it is so trifling as to have escaped observation: it must therefore be concluded, that the globe is homogeneous, or nearly so in all its parts.

If the earth was a hollow and void globe, and the crust of which, for example, not more than two or three miles thick; it would

produce these effects. 1. The mountains would be such considerable parts of the whole thickness of the crust, that great irregularities in the motions of the Earth would be occasioned by the attraction of the Moon and Sun: for when the highest parts of the globe, as the Cordeliers, should have the Moon at noon, the attraction would be much stronger on the whole globe than when she was in the meridian of the lowest parts. 2. The attraction of mountains would be much more considerable than it is in comparison with the attraction of the whole globe, and experiments made at the mountain of Chimboraco, in Peru, would in this case give more degrees than they have given seconds for the deviation of the plumb line. 3. The weight of bodies would be greater on the tops of high mountains than on the planes; so that we should feel ourselves considerably heavier, and should walk with more difficulty in high than in low places. These observations, with many others that might be added, must convince us, that the inner parts of the globe is not void, but filled with a dense matter.

On the other hand, if below the depth of two or three miles, the earth was filled with

a matter much more dense than any known, it would necessarily occur, that every time we descended to moderate depths, we should weigh much more, and the motion of pendulums would be more accelerated than in fact they are when carried from an eminence into a plain: thus, we may presume that the internal part of the Earth is filled with a matter nearly similar to that which composes its surface. What may complete our determination in favour of this opinion is, that in the first formation of the globe, when it took its present spheroidical figure, the matter which composed it was in fusion, and, consequently, all its parts were homogeneous, and nearly equally dense. From that time the matter on the surface, although originally the same with the interior, has undergone a variety of changes by external causes, which has produced materials of such different densities; but it must be remarked, that the densest matters, as gold and metals, are also those the most seldom to be met with, and consequently the greatest part of the matter at the surface of the globe has not undergone any very great changes with relation to its density; the most common materials, as sand and clay, differ very little, insomuch, that we may conjecture,

with great probability, that the internal part of the earth is composed of a vitrified matter, the density of which is nearly the same as that of sand, and that consequently the terrestrial globe in general may be regarded as homogeneous.

Notwithstanding this, it may be urged, that although the globe was composed of concentrical strata of different densities, the diurnal motion might be equally certain, and the uniform inclination of the axis as constant and undisturbed as it could be, on the supposition of its being composed of homogeneous matter. I acknowledge it, but I ask at the same time, if there is any reason to believe that strata of different densities do exist? If these conclusions be not rather a desire to adjust the works of Nature to our own ideas? And whether in physics we ought to admit suppositions which are not founded on observations or analogy?

It appears, therefore, that the earth, by virtue of the mutual attraction of its parts and its diurnal motion, assumed the figure of a spheroid; that it necessarily took that form from being in a state of fluidity; that, agreeable to the laws of gravity and of a centrifugal force, it could have no other figure: that in the moment of its

formation as at present, there was a difference between the two diameters equal to a 230th part, and that, consequently, every hypothesis in which we find greater or less difference are fictions which merit no attention.

But it may be said, if this theory is true, and if 229 to 230 is the just relation of the axis, why did the mathematicians, sent to Lapland and Peru, agree to the relation of 174 to 175? From whence does this difference arise between theory and practice? And is it not more reasonable to give the preference to practice and measures, especially when we have been taken by the most able mathematicians of Europe[109:A], and with all necessary apparatus to establish the result.

To this I answer, that I have paid attention to the observations made at the equator and near the polar circle; that I have no doubt of their being exact, and that the earth may possibly be elevated an 175th part more at the equator than at the poles. But, at the same time, I maintain my theory, and I see clearly how the two conclusions may be reconciled. This difference is about four leagues in the two axes, so that the parts at the equator are raised two leagues more

than they ought to be, according to my theory; this height answers exactly to the greatest inequalities on the surface of the globe, produced by the motion of the sea, and the action of the fluids. I will explain; it appears that when the earth was formed, it must necessarily have taken, by virtue of the mutual attraction of its parts, and the action of the centrifugal force, a spheroidical figure, the axes of which differ a 230th part: the original earth must have had this figure, which it took when it was fluid, or rather liquified by the fire; but after its formation the vapours which were extended and rarefied, as in the atmosphere and tail of a comet, became condensed, and fell on the surface in form of air and water: and when these waters became agitated by the flux and reflux, the matters were, by degrees, carried from the poles towards the equatorial parts; so that the poles were lowered about a league, and those of the equator raised in the same proportion; this was not suddenly done, but by degrees in succession of time; the earth being also exposed to the action of the winds, air, and sun; all these irregular causes concurred with the flux and reflux to furrow its surface, hollow it into valleys, and raise it into mountains; and

producing other inequalities and irregularities, of which, nevertheless, the greatest thickness does not exceed one league at the equator; this inequality of two leagues, is, perhaps, the greatest which can be on the surface of the earth, for the highest mountains are scarce above one league in height, and there is much probability of the sea's not being more at its greatest depth. The theory is therefore true, and practice may be so likewise; the earth at first could not be raised above 6-1/2 leagues more at the equator than the poles, but the changes which have happened to its surface might afterwards raise it still more. Natural History wonderfully confirms this opinion, for we have proved in the preceding discourse that the flux and reflux, and other motions of the water, have produced mountains and all the inequalities on the surface of the globe, that this surface has undergone considerable changes, and that at the greatest depths, as well as on the greatest heights, bones, shells and other wrecks of animals, which inhabit the sea and earth, are met with.

It may be conjectured, from what has been said, that to find ancient earth, and matters which have never been removed from the spot

in which they were first placed, we must dig near the poles, where the bed of the earth must be thinner than in the Southern climates.

On the whole, if we strictly examine the measures by which the figure of the earth is determined, we shall perceive this hypothesis enters into such determination; for it supposes the earth to have the figure of a regular curve, whereas from the constant changes the earth is continually undergoing from a variety and combination of causes, it is almost impossible that it should have retained any regular figure, and hence the poles might, originally, only be flattened a 230th part, as Newton says, and as my theory requires. Besides, although we had exactly the length of the degree at the polar circle and equator, have we not also the length of the degree as exactly in France? And the measure of M. Picard, has it not been verified? Add to this that the augmentation and diminution in the motion of the pendulum, do not agree with the result drawn from measurement, and that, on the contrary, they differ very little from the theory of Newton. This is surely more than is requisite to convince us that the poles are not flattened more than a 230th part, and that if

there is any difference, it can proceed only from the inequalities, which the water and other external causes have produced on its surface; but these inequalities being more irregular than regular, we must not form any hypothesis thereon, nor suppose, that the meridians are ellipses, or any other regular curves. From whence we perceive, that if we should successively measure many degrees of the earth in all directions, we still should not be certain by that alone, of the exact situation of the poles, nor whether they were depressed more or less than the 230th part.

May it not also be conjectured, that if the inclination of the axis of the earth has changed, it can only be produced by the changes which have happened to the surface, since all the rest of the globe is homogeneous; that consequently this variation is too little sensible to be perceived by astronomers, and that if the earth is not encountered with a comet, or deranged, by any other external cause, its axis will remain perpetually inclined as it is at present, and as it has always been?

In order not to omit any conjecture which appears reasonable, may it not be said, that as the mountains and inequalities which are on the

surface of the earth have been formed by the flux and reflux of the sea, the mountains and inequalities which we remark on the surface of the moon, have been produced by a similar cause? they certainly are much higher than those of the earth, but then her tides are also much stronger, occasioned by the earth's being considerably larger than the moon, and consequently producing her tides with a superior force; and this effect would be much greater if the moon had, like the earth, a rapid rotation; but as the moon presents always the same surface to the earth, the tides cannot operate but in proportion to the motion arising from her libration, by which it alternatively discovers to us a segment of its other hemisphere; this, however, must produce a kind of flux and reflux, quite different from that of our sea, and the effects of which will be much less considerable than if the moon had from its course a revolution round its axis, as quick as the rotation of the terrestrial globe.

I should furnish a volume as large as that of Burnet or Whiston's, if I were to enlarge on the ideas which arise in support of the above; by giving them a geometrical air, in imitation of the last author, I might add considerably to

their weight; but, in my opinion, hypothesis, however probable, ought not to be treated with such pomposity; it being a dress which borders so much on quackery.

FOOTNOTES:

[78:A] Vide Newton, 2d edit. page 525.

[79:A] Vid. Newton, page 405.

[109:A] M. de Maupertuis' Figure of the Earth.

ARTICLE II.
FROM THE SYSTEM OF WHISTON[115:A].

This Author commences his treatise by a dissertation on the creation of the world; he says that the account of it given by Moses in the text of Genesis has not been rightly understood; that the translators have confined themselves too much to the letter and superficial views, without attending to nature, reason, and philosophy. The common notion of the world being made in six days, he says is absolutely false, and that the description given by Moses, is not an exact and philosophical narration of the creation and origin of the universe, but only an historical representation

of the terrestrial globe. The earth, according to him, existed in the chaos; and, at the time mentioned by Moses, received the form, situation and consistency necessary to be inhabited by the human race. I shall not enter into a detail of his proofs, nor undertake their refutation. The exposition we have just made, is sufficient to demonstrate the difference of his opinion with public facts, its contrariety with scripture, and consequently the insufficiency of his proofs. On the whole, he treats this matter as a theological controvertist, rather than as an enlightened philosopher.

Leaving these erroneous principles, he flies to ingenious suppositions, which, although extraordinary, yet have a degree of probability to those who, like him, incline to the enthusiasm of system. He says, that the ancient chaos, the origin of our earth, was the atmosphere of a comet: that the annual motion of the earth began at the time it took its new form, but that its diurnal motion began only when the first man fell. That the ecliptic cut the tropic of cancer, opposite to the terrestrial paradise, which was situated on the north-west side of the frontiers of Assyria: that before the deluge, the year began at the autumnal equinox:

that the orbits of the planets, and the earth were then perfect circles. That the deluge began the 18th of November, 2365 of the Julian period, or 2349 years before Christ. That the solar and lunar year were then the same, and that they exactly contained 360 days. That a comet descending in the plane of the ecliptic towards its perihelion, passed near the globe of the earth the same day as the deluge began: that there is a great heat in the internal part of the terrestrial globe, which constantly diffuses itself from the centre to the circumference; that the form of the earth is like that of an egg, the ancient emblem of the globe; that mountains are the lightest part of the earth, &c. He afterwards attributes all the alterations and changes which have happened to the earth, to the universal deluge; then blindly adopts the theory of Woodward, and indiscriminately makes use of all the observations of that author on the present state of the globe; but assumes originality when he speaks of its future state: according to him it will be consumed by fire, and its destruction will be preceded by terrible earthquakes, thunder, and frightful meteors; the Sun and Moon will have an hideous aspect, the heavens will appear to

fall, and the flames will be general over all the earth; but when the fire shall have devoured all the impurities it contains; when it shall be vitrified and rendered transparent as crystal, the saints and the blessed spirits will return and take possession of it, and there remain till the day of judgment.

These hypotheses, at the first glance, appear to be rash and extravagant assertions; nevertheless the author has managed them with such address, and treated them with such strength, that they cease to appear absolutely chimerical. He supports his subjects with much science, and it is surprising that, from a mixture of ideas so very absurd, a system could be formed with an air of probability. It has not affected vulgar minds so much as it has dazzled the eyes of the learned, because they are more easily deceived by the glare of erudition, and the power of novel ideas. Mr. Whiston was a celebrated astronomer, in the constant habit of considering the heavens, observing the stars, and contemplating the wonderful course of nature; he could never persuade himself that this small grain of sand, this Earth which we inhabit, occupied more the attention of the Creator than the universe, the vast extent of which

contains millions of other Suns and Earths. He pretends, that Moses has not given us the history of the first creation of this globe, but only a detail of the new form that it took when the Almighty turned it from the mass of a comet into a planet, and formed it into a proper habitation for men. Comets are, in fact, subjected to terrible vicissitudes by reason of the eccentricity of their orbits. Sometimes, like that in 1680, it is a thousand times hotter there than red-hot iron; and sometimes a thousand times colder than ice; if they are, therefore, inhabited it must be by strange creatures, of which we can have no conception.

The planets, on the contrary, are places of rest, where the distance of the sun not varying much, the temperature remains nearly the same, and permits different kinds of plants and animals to grow and multiply.

In the beginning God created the world; but, observes our author, the earth was then an uninhabitable comet, suffering alternatively the excess of heat and cold, its liquifying and freezing by turns formed a chaos, or an abyss, surrounded with thick darkness: "and darkness covered the face of the deep," & tenebræ erant superfaciam abissi. This chaos was the

atmosphere of the comet, a body composed of heterogeneous matters, the centre occupied by spherical, solid, and hot substances, of about two thousand leagues in diameter, round which a very great surface of a thick fluid extended, mixed with an unshapen and confused matter, like the chaos of the ancient rudis & indigestaque moles.

This vast atmosphere contained but very few dry, solid, or terrestrial particles, still less aqueous or aerial, but a great quantity of fluid, dense and heavy matters, mixed, agitated and jumbled together in the greatest disorder and confusion. Such was the earth before the six days, but on the first day of the creation, when the eccentrical orbit of the comet had been changed, every thing took its place, and bodies arranged themselves according to the law of gravity, the heavy fluid descended to the lowest places, and left the upper regions to the terrestrial, aqueous and aerial parts; those likewise descended according to their order of gravity; first the earth, then the water, and last of all the air. The immense volume of chaos was thus reduced to a globe of a moderate size, in the centre of which is the solid body that still retains the heat which the sun formerly communicated to it, when it belonged to a

comet. This heat may possibly endure six thousand years, since the comet of 1680 required fifty thousand years to cool. Around this solid and burning matter, which occupies the centre of the earth, the dense and heavy fluid which descended the first is to be found, and this is the fluid which forms the great abyss on which the earth is borne, like cork on quicksilver; but as the terrestrial parts were originally mixed with a large quantity of water, in descending they have dragged with them a part of this water, which, not being able to re-ascend after the earth was consolidated, formed a concentrical bed with the heavy fluid which surrounds this hot substance, insomuch that the great abyss is composed of two concentrical orbs, the most internal of which is a heavy fluid, and the other water; the last of which serves for a foundation to the earth. It is from this admirable arrangement, produced by the atmosphere of a comet, that the Theory of the Earth, and the explanation of all its phenomena are to depend.

When the atmosphere of the comet was once disembarrassed from all the solid and terrestrial matters, there remained only the lighter air, through which the rays of the

sun freely passed and instantly produced light: "Let there be light, and there was light." The columns which composed the orb of the Earth being formed with such great precipitation is the cause of their different densities: consequently the heaviest sunk deeper into this subterraneous fluid than the lightest; and it is this which has produced the vallies and mountains on the surface of the earth. These inequalities were, before the deluge, dispersed and situated otherwise than they are at present. Instead of the vast valley, which contains the ocean, there were many small divided cavities on the surface of the globe, each of which contained a part of this water; the mountains were also more divided, and did not form chains as at present: nevertheless, the earth contained a thousand times more people, and was a thousand times more fertile; and the life of man and other animals were ten times longer, all which was affected by the internal heat of the earth that proceeded from the centre, and gave birth to a great number of plants and animals, bestowing on them a degree of vigour necessary for them to subsist a long time, and multiply in great abundance. But this heat, by increasing the strength of