ART. X.

Hiftoire Naturelle, Generale et Particuliere, contenant les Epoches de la Nature.-i. e. A Natural History, General and Particular; containing the Epochas of Nature. By the Count de Buffon, &c. Supplement, Vol. V. 4to. Paris. 1778.

T is well known, that this bold genius, who is certainly more adventurous than prudent in his philofophical flights, fent forth, many years ago, an hypothetical comet, to dafh out of the fun, as many portions of his fluid fiery fubftance, as compofe, at this day, the revolving planets in the folar fyftem. -It is alfo known, that he has lately ventured to follow these planets from their pretended original state of fluidity or liquefaction, through their decreafing degrees of heat; and thus to measure the time elapfed in their refpective approach to, or arrival at, a ftate of confiftence, and a capacity of producing and fupporting animal beings.-The calculations and fancies he has exhibited on this fubject, muft (if we are not much mistaken) have made him fmile inwardly at the liberty, which he fees, that a spoilt child of fame may take with the public.

In the work before us, the ingenious Author comes nearer home for the principles of his inveftigation. As the hiftorian examines scattered fragments of records, and unriddles ancient and half-decayed infcriptions and medals, in order to afcertain the epochas of civil revolutions, and fix the dates of moral actions, and political events,-fo does our Naturalift rummage in the archives of the phyfical world, and draw from the bowels of the earth, and the bottom of the ocean, proofs and indications of thofe phyfical changes and revolutions, that lead to a knowledge of the different ages, or epochas of nature. This vaft undertaking aims at nothing lefs than an hiftorical tablature of what nature has been in those remote and ancient times, when there were no fpectators to record her operations, and what fhe will be in those diftant periods of a dark futurity, when (according to the comfortable philofophy of our Author) there will be no witnesses of her dreary ftate, and difmal existence. A goodly undertaking for a being, placed on a point of infinite space, and in a moment of endless duration! However, let us hear him. Our readers will judge by a brief, but juft sketch, of his method of proceeding and deciding, whether his fame be owing to the folidity of his inveftigations and discoveries, or to those fublime flights, and that magic power, energy, and grace of ftyle, that have aftonished and bewitched a confiderable part of Europe.

The hiftory of nature, fays he, is that of all fubftances, places, and ages; and though it feems, at firft fight, that her ftupendous works undergo no alteration, and that, even in her M m 2

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most frail and transitory productions, the remains always the fame, becaufe, every moment, her primitive models are conftantly re-exhibited to our view, under new representations; yet, on a more attentive confideration of things, we shall find, that her courfe is not fo uniform, that it admits of ftriking variations, and fucceffive changes, and, that befides the modifications it has received from the labours of man, it yields, of itself, to new combinations, to various alterations, both of matter and form; and that its parts are as changeable, as the whole appears fixed, uniform, and conftant." Thefe changes our Author

calls the Epochas of Nature.

The earth then, according to his hypothefis, is, at prefent, different from what it was in the beginning, and alfo, from what it has been in fucceeding periods of time. To form an idea of its ancient ftate, we muft contemplate nature in those regions that have been newly difcovered, and have been always uninhabited; and even this ancient ftate may be confidered (we speak here, and throughout, the language of our Author) as modern, when compared with that, in which the earth was, when its continents were covered with water, when the finny race inhabited our plains, and our mountains were the fhoals of the

ocean.

In order to ascertain the epochas of nature, M. DE BUFFON deduces the knowledge of its paft and fucceffive aspects, from the materials that are furnished by its prefent ftate: his fources of information and evidence on this fubject, are facts, monuments, or remains, and traditions, connected by analogies. The facts he builds upon are the following: Firft, The earth is raised at the equator, and flatted towards the poles, in a proportion conformable to the laws of gravity, and of the centrifugal force.-Secondly, The earth has an internal heat, which is peculiar to it, and independent on that which it receives from the rays of the fun.-Thirdly, The heat, which the earth derives from the fun, is but small, when compared with its own inherent warmth; and the heat, communicated by the fun, would not be fufficient, alone, to fupport the principle of life in animal nature.-Fourthly, The fubftances, which enter into the compofition of the terreftrial globe are, in general, of a glaffy nature, and are all fufceptible of vitrification.-This fact is highly difputable, if not palpably falfe.-Fifthly, we find over the whole furface of the earth, and even upon mountains, at the height of 1502 fathoms, an immenfe quantity of fhells, and other fragments of marine productions.

The first of these facts, is fufficiently proved by the theory of gravitation, and the experiments made with the pendulum; and as this form of the earth is fuch, as a fluid globe would affume, by turning upon its axis, with a degree of velocity equal to

that

that of the earth's motion, our Author concludes, from hence, that the matter, of which our earth is compofed, was in a fluid ftate, the moment it received its form, and that this was the moment in which it began to turn upon its axis. He concludes alfo, that the fluidity of the earth was a liquefaction occafioned by fire, from this confideration, that the greateft part of the folid fubftances that compofe our globe, are not diffolveable by water.-This conclufion, according to our Author, derives a farther degree of probability from the fecond fact. The internal heat of the globe, which ftill fubfifts, proves, that the primitive fire, that produced its fluidity, is not yet entirely diffipated or extinguished. Undoubted and repeated experiments prove, that the furface of our globe is much cooler than its internal parts. The comparison of our winters with our fummers, demonftrates this internal heat, which, moreover, becomes palpable, when we defcend into the earth, is perceivable in all parts of the globe, and feems to increase in proportion as we descend beneath its furface. This internal heat is farther proved, by our Author, by the effects of electricity, and by the temperature of the water of the fea, which, at the fame depth, is nearly equal to that of the interior parts of the earth. M. BUFFON goes ftill farther: he pretends, that the limpidness of the water of the ocean cannot be owing to the influence of the fun, fince it is demonftrated by experience, that the folar rays pafs no farther thah 600 feet through the clearest water, and that of confequence, the heat of the fun does not extend to the fourth part of that mass, that is, to 150 feet: fo that the whole body of water, below that depth, would be entirely frozen, without the internal heat of the earth, which alone can maintain their fluidity-Our Author adds several other obfervations to confirm the third fact;-it feems, indeed, to be afcertained by experience; for this proves, that the heat of the folar rays does not go deeper into the earth than 15 or 20 feet, fince ice is preserved, at that depth, in the warmest fummers. Hence he concludes, that the temperature of the earth, and the fluidity of the ocean, are both produced by an internal heat peculiar to the earth, and entirely independent on the rays of the fun.

M. DE BUFFON refers us to his theory of the earth, for the arguments that prove all the fubftances, which compose our globe, to be of a glaffy nature, and fufceptible of vitrification : even thofe, which the chymifts look upon as refractory, and infufible, because they refift the action of the fire in their crucibles and furnaces. And thus he thinks the primitive liquefaction and fluidity of the earth amply proved.

But though this philofopher is of opinion, that all the ingredients of our globe were originally glaffy, and are still capable of vitrification, he, nevertheless, diftinguishes them in a

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manner conformable to the different modifications through which they pafs, before they return to their primitive ftate. He therefore divides them into two claffes, vitrifiable and calcinable: the fubftances of the firft clafs undergo no change from the action of fire, unlefs it be carried to a degree of heat capable of converting them into glafs; while thofe, on the contrary, of the fecond clafs, are reduced to calxes, by the action of a fire confiderably lefs violent. The calcinable fubftances, or matters, though confiderable in number throughout the globe, are yet few in comparison with those that are vitrifiable. The fifth fact above mentioned, proves, according to our Author, that the former owe their existence to another period, and a different element; and it appears evident to him, that all the matters, not immediately produced by the action of the primitive fire, were formed by the intervention of water; fince they are compofed of fhells and other fragments of marine productions.

After a particular enumeration of the different matters that are fufceptible of immediate vitrification, our Author obferves, that all the matters which are converted into calxes, exhibit, in this change, not their primitive, but a secondary nature, which they have contracted, by paffing through filters in which they have degenerated from their original character of glaffy fubftances; they are all compofed of madreporas, fhells, and of the caft fkins and carcaffes of thofe aquatic animals, which alone can convert liquids into folids, and transform the feawater into a ftony fubftance. All this, fays our Author, may be proved, by an attentive inspection of thefe fubftances, and by an obfervation of the remains and fragments of nature.

Thefe remains are, firft, The fhells and other marine productions, which are found at the furface, and in the interior parts, of the earth, and belonged to fpecies of animals that are not obferved in the adjacent feas:-fecondly, Skeletons, remains, and bones of elephants, hippopotamufes, and rhinocerofes, which are found in Siberia, and the other northern countries of Europe and Afia, in fufficient quantities, to convince us, that thofe animals which cannot now propagate their fpecies any where but in the fouthern parts of the globe, exifted and procreated, in former times, in the regions of the north. It has been obferved, that thefe remains of elephants, and other terreftrial animals, are not fituated far below the furface of the earth, while the remains of aquatic animals, and marine productions, are found at a much greater depth in the interior parts of the globe. The teeth and bones of the elephant, and the hippopotamus, are not only found in the northern parts of cur Continent, but alfo in North America, though in this latter region thofe animals are unknown.

By

By comparing thefe remains with the facts, our Author is led to conclude, that the formation of vitrifiable matters, takes its date from a much more remote antiquity than that of the compofition of calcareous fubftances; and on thefe data, he founds the first five of the Seven Epochas of Nature, contained in this volume.

The first epocha was, when the matter of this globe being in fufion, by the action of fire, the earth affumed its form, and, by its rotatory movement, fwelled under the equator, and flattened under the poles ;-the fecond,-When the matter of the globe, becoming folid, gave rife to the formation of the great maffes of vitrifiable fubftances; the third,-When the fea, covering our continents, nourished thofe fhell-fifh and aquatic animals, from whofe remains calcareous fubftances have been formed;-fourth,-When thofe feas that covered our continents retired, and the volcanos began to act; —and the fifth, (as clearly indicated, fays our Author, as the preceding,-which we may believe without any great ftretch of faith)-When the elephants, and other fouthern animals, inhabited the regions of the north,-a period much later than the four now mentioned as is concluded, from the fituation of the remains of these terrestrial animals, which are much nearer the furface of the earth, than thofe of marine animals.

Our Author was fenfible, that wags, hiftorians, and philofo phers, would all join in an outcry at this paradox; he, therefore, has collected materials to prove the fact; and then he makes use of the fact to confirm his favourite hypothefis. His reasoning amounts to this-there are great quantities of ivory, and bones of elephants, difcovered daily in the northern regions. of Europe, Afia, and America :-from hence it follows, that thefe animals (which can only fubfift, and, in effect, do only fubfift, at prefent, in warm countries) must have formerly exifted in the northern climates- and therefore, that the frigid zone must have been then as warm as our torrid zone is at this day.

M. DE BUFFON refutes the objections that may be made to his hypothefis, by those who maintain that the facts here alleged may be accounted for by other caufes, fuch as inundations in the fouthern parts of the globe, which drove the elephants towards the north, where they left their carcaffes, having perished by the intense cold of that climate;-he alfo endeavours to fortify his hypothefis against the reports of thofe travellers, who maintain, that the ivory found in Siberia is that of the Morfe, or fea-cow-he, finally, combats the reasonings of those, who, though difpofed to think that the northern cimates were much warmer, in days of yore, than they are at prefent, yet attribute this difference, not to his refrigerating fyftem, but to a change of

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