Chapter XVI: Section III (10)

The number of these bones, accumulated in the same place, is matter of astonishment, when it is considered, that the animals to which they belonged were carnivorous, so that more than two can never have lived in the same cavern at the same time. The caves of Bayreuth seem to have been the den and the tomb of a whole dynasty of unknown monsters, that issued from this central spot to devour the feebler inhabitants of the woods, during a long succession of ages, before man had subdued the earth, and freed it from all domination but his own.

407. The fossil bones of the second and third class, but chiefly of the third, have now afforded matter of conjecture and discussion for more than a century. The facts with respect to them are very numerous and interesting, but can be considered here only very generally.

The remains of this kind, consist of the bones only of large animals, so that they have generally been compared with those of the elephant, the rhinoceros, the hippopotamus, or other animals of great size The bones of smaller animals have also been found, but much more rarely than the other. It is usually remarked, that the bones thus discovered in the earth are larger than those of the similar living animals.

Another general fact concerning these remains, is, that they are found in all countries whatsoever, but always in the loose or travelled earth, and never in the genuine strata. Since the year 1696, when the attention of the curious was called to this subject, by the skeleton of an elephant dug up in Thuringia, and described by Tentzelius,[212] there is hardly a country in Europe which has not afforded instances of the same kind. Fossil bones, particularly grinders and tusks of elephants, have been found in other places of Germany, in Poland, France, Italy, Britain, Ireland, and even Iceland.[213] Two countries, however, afford them in greater abundance by far than any other part of the known world; namely, the plains of Siberia in the old continent, and the flat grounds on the banks of the Ohio in the new.[214]

[Footnote 212: Phil. Trans. vol. xix. p. 757.]

[Footnote 213: A grinder of an elephant found in Iceland, is described by _Bartholinus_, Acta Hafniens. vol. i. p. 83.]

[Footnote 214: The fossil bones on the Ohio are described in two papers by Mr P. Collinson, Phil. Trans. vol. lvii. p. 464 and 468.]

408. When the bones in Siberia were first discovered, they were supposed to belong to an animal that lived under ground, to which they gave the name of the _mammouth_; and the credit bestowed on this absurd fiction, is a proof of the strong desire which all men feel of reconciling extraordinary appearances with the regular course of nature. Much skill, however, in natural history was not required to discover that many of the bones in question resembled those of the elephant, particularly the grinders and the tusks of that animal. Others resembled the bones of the rhinoceros; and a head of that kind, having the hide preserved upon it, was found in Siberia, and is still in the imperial cabinet at Petersburgh.

Pallas has described the fossil bones which he found in the museum at Petersburgh, on his being appointed to the superintendence of it, and enumerates, not only bones that belong, in his opinion, to the elephant and rhinoceros, but others that belong to a kind of buffalo, very different from any now known, and of a size vastly greater.[215] He has also described, in another very curious memoir, the bones of the same kind that he met with in his travels through the north-east parts of Asia.

[Footnote 215: Novi Comment Petrop. tom. xiii. (1768,) p. 436, and tom. xvii. p. 576, &c.]

The fossil bones found on the banks of the Ohio, resemble in many things those of Siberia; like them they are contained in the soil or alluvial earth, and never in the solid strata; like them too they are no otherwise changed from their natural state, than by being sometimes slightly calcined at the surface; they are also of great size, and in great numbers, being probably the remains of several different species.

409. Two inquiries concerning these bones have excited the curiosity of naturalists; first, to discover among the living tribes at present inhabiting the earth, those to which the fossil remains may with the greatest probability be referred; and, secondly, to find out the cause why these remains exist in such quantities, in countries where the animals to which they belong, whatever they be, are at present unknown. The solution of the first of these questions, is much more within our reach than the second, and at any rate must be first sought for.

On the authority of so eminent a naturalist as Pallas, the bones from Siberia may safely be referred to the elephant, the rhinoceros, and buffalo, as mentioned above, though perhaps to varieties of them with which we are not now acquainted. With respect to the bones of North America, the question is more doubtful, for they have this particular circumstance attending them, viz. that along with the thighbones, tusks, &c. which might be supposed to belong to the elephant, grinders are always found of a structure and form entirely different from the grinders of that animal.[216] Some naturalists, particularly M. DAUBENTON, referred these grinders to the hippopotamus; but Dr W. HUNTER appears to have proved, in a very satisfactory manner, that they cannot have belonged to either of the animals just mentioned, but to a _carnivorous_ animal of enormous size, the race of which, fortunately for the present inhabitants of the earth, seems now to be entirely extinct.[217] The foundation of Dr Hunter's opinion is, that in these grinders the enamel is merely an external covering; whereas, in the elephant, and other animals destined to live on vegetable food, the enamel is intermixed with the substance of the tooth.[218]

[Footnote 216: See Mr Collinson's papers, above referred to. Phil. Trans. vol. lvii.]

[Footnote 217: Phil. Trans. vol. lviii. p. 3, &c.]

[Footnote 218: A fossil grinder in the collection of JOHN MACGOWAN, Esq. of Edinburgh, answers nearly to Mr Collinson's description, and is very well represented by the figure which accompanies it. This grinder weighs four pounds one-fourth avoirdupois; the circumference of the _corona_ is eighteen inches; the coat of enamel is one-fourth of an inch thick; there are five double teeth; in Mr Collinson's specimen there are only four.]

410. Though this argument appears to be of considerable weight, yet CAMPER, who was greatly skilled in comparative anatomy, and who had studied this subject with particular attention, was of opinion, that these grinders belong to a species of elephant. This opinion he states in a letter to Pallas, who had found grinders and other bones of this same animal, on the western declivity of the Ural mountains.[219] Camper denies that the animal is carnivorous, because the _incisores_, or canine teeth, are wanting; and he argues farther, from the weight of the head, which may be inferred from the weight of the grinders, that the neck must have been short, and the animal must have been furnished with a _proboscis_. He afterwards abandoned the latter hypothesis, and gave it as his opinion that the _incognitum_ was neither carnivorous, nor a species of the elephant.[220]

[Footnote 219: Acta Acad. Petrop. tom. i. (1777,) pars posterior, p. 213, &c.]

[Footnote 220: _Ibid._ tom. ii. (1784,) p. 262.]

411. Nevertheless, CUVIER, in a _mémoire_ read before the National Institute of Paris, maintains, that the fossil bones of the new Continent, as well as most of those of the old, belong to certain species of the elephant; of which, at least, two do not now exist, and are only known from remains preserved in the ground. He distinguishes them thus:[221]

[Footnote 221: Mémoires de l'Institut National, Sciences Physiques, tom. ii. p. 19, &c.]

_Elephas mammonteus_,--_maxillâ obtusiore, lamellis molarium tenuibus, rectis_.

_Elephas Americanus_,--_molarities multicuspidibus, lamellis post detritionem quadric-lobatis_.

The latter species, which is meant to include the _animal incognitum_, is said to have lived, not only in America, but in many parts of the old Continent. Yet some late inquiries into the structure of the teeth of graminivorous animals, and particularly of the elephant, make it very improbable that the _incognitum_ has belonged to this genus.[222] The grinders of the elephant have been found to consist of three substances, enamel, bone, and what is called the _crusta petrosa_, applied in layers, or folds contiguous to one another; and no vestige of this structure appears in the grinders of the unknown animal of the Ohio.[223] At the same time, Dr Hunter's assertion, that this animal was carnivorous, is rendered doubtful, not only by the want of _canine_ teeth, but also from the resemblance between its grinders and those of the wild boar, which Mr Home has observed to be considerable.[224] The grinder of the boar is similar to that of the elephant, in the extent of the masticating surface, but not at all in the internal structure; and the same is true of the tooth of the _animal incognitum_, so that a considerable probability is established, that it and the boar are of the same genus, and both destined to live occasionally either on animal or vegetable food.

[Footnote 222: See Mr Home's Observations on the Teeth of Graminivorous Animals, Phil. Trans. 1799. Also, an Essay on the Structure of the Teeth, by Dr Blake.]

[Footnote 223: In a paper inserted in the fourth volume of the American Philosophical Transactions, an account is given of two different grinders that are found at the Salt Licks near the Ohio. One of them resembles the grinder of the elephant, and may have belonged to the _Elephas Americanus_ of Cuvier; the other agrees pretty nearly with the grinder of Dr Hunter's _animal incognitum_. The author of the paper thinks that the _animal incognitum_ was not wholly carnivorous, as the incisores, or canine teeth, are never found. At the Great Bone Lick, bones of smaller animals, particularly of the buffalo kind, have been discovered. The saline impregnation of the earth at these Licks must no doubt have contributed to the preservation of the bones. Trans. American Phil. Soc. vol. iv. (1799,) p. 510, &c.]

[Footnote 224: Observations on the Grinding Teeth of the wild boar and _animal incognitum_. Phil. Trans. 1801, p. 319.]

412. Another _animal incognitum_ found in South America has been described by Cuvier, and appears to be of a different genus from the _incognitum_ of the North. Thus, if we include the two _incognita_ of America, the _elephas mammonteus_, the unknown buffalo of Pallas, and the great animal of Bayreuth, we have at least five distinct genera, or species of the animal kingdom, which existed on our continents formerly, but do not exist on them now. The number is probably much greater: Pallas mentions fossil horns of a gazelle, of an unknown species; and horns of deer are often found, that cannot be referred to any species now existing. Those extinct races have been remarkable for their size: some of the ancient elephants appear to have been three times as large as any of the present.[225]

[Footnote 225: Camper, Nov. Acta Petrop. tom. ii. (1784) p. 257.]

413. The inhabitants of the globe, then, like all the other parts of it, are subject to change. It is not only the individual that perishes, but whole _species_, and even perhaps _genera_, are extinguished. It is not unnatural to consider some part of this change as the operation of man. The extension of his power would necessary subvert the balance that had before been established between the inhabitants of the earth, and the means of their subsistence. Some of the larger and fiercer animals might indeed dispute with him, for a long time, the empire of the globe; and it may have required the arm of a Hercules to subdue the monsters which lurked in the caves of Bayreuth, or roamed on the banks of the Ohio. But these, with others of the same character, were at length exterminated: the more innocent species fled to a distance from man; and being forced to retire into the most inaccessible parts, where their food was scanty, and their migration checked, they may have degenerated from, the size and strength of their ancestors, and some species may have been entirely extinguished.

But besides this, a change in the animal kingdom seems to be a part of the order of nature, and is visible in instances to which human power cannot have extended. If we look to the most ancient inhabitants of the globe, of which the remains are preserved in the strata themselves, we find in the shells and corals of a former world hardly any that resemble exactly those which exist in the present. The species, except in a few instances, ate the same, but subject to great varieties. The vegetable impressions on slate, and other argillaceous stones, can seldom be exactly recognised; and even the insects included in amber are different from those of the countries in which the amber is found.

414. Supposing, then, the changes which have taken place in the qualities and habits of the animal creation, to be as great as those in their structure and external form, we can have no reason to wonder if it should appear that some have formerly dwelt in countries from which the similar races are now entirely banished. The power of living in a different climate, of enduring greater degrees of cold or of heat, or of subsisting on different kinds of food, may very well have accompanied the other changes. Though one species of elephant may now be confined to the southern parts of Asia, another may have been able to endure the severer climates of the north; and the same may be true of the buffalo or the rhinoceros. In all this no physical impossibility is involved; though whether it is a probable solution of the difficulty concerning the origin of these animal remains, can only be judged of from other circumstances.

415. If we consider attentively the facts that respect the Siberian fossil bones, there will appear insurmountable objections to every theory that supposes them to be exotic, and to have been brought into their present situation from a distant country.

The extent of the tract through which these bones are scattered, is a circumstance truly wonderful. Pallas assures us,[226] that there is not a river of considerable size in all the north of Asia, from the Tanais, which runs into the Black Sea, to the Anadyr, which falls into the Gulf of Kamtchatka, in the sides or bottom of which bones of elephants and other large animals have not been found. This is especially the case where the rivers run in plains through gravel, sand, clay, &c.; among the mountains, the bones are rarely discovered. The extent of the tract just mentioned exceeds four thousand miles; and how the bones could be distributed over all that extent, by any means but by the animals having lived there, it seems impossible to conceive. No torrent nor inundation could have produced this effect, nor could the bones brought in that way have been laid together so as to form complete skeletons.

[Footnote 226: De Reliquiis Animalium exoticorum, per Asiam Borealem repertis.--"Nov. Comment Petrop. tom. xvii. (1772,) p. 576.]

416. One fact recorded by the same author, seems calculated to remove all uncertainty. It is that of the carcase of a rhinoceros, almost entire, and covered with the hide, found in the earth in the banks of the river Wilui, which falls into the Lena below Jakutsk.[227] Some of the muscles and tendons were actually adhering to the head when Pallas received it. The head, after being dried in an oven, is still preserved in the museum at Petersburgh. The preservation of the skin and muscles of this natural mummy, as Pallas calls it, was no doubt brought about by its being buried in earth that was in a state of perpetual congelation; for the place is in the parallel of 64°, where the ground is never thawed but to a very small depth below the surface.

[Footnote 227: Pallas _ubi supra_, p. 586. Also, Voyages de Pallas, tom. iv. p. 131.]

But by what means can we account for the carcase of a rhinoceros being buried in the earth, on the confines of the polar circle? Shall we ascribe it to some immense torrent, which, sweeping across the deserts of Tartary, and the mountains of Altai, transported the productions of India to the plains of Siberia, and interred in the mud of the Lena the animals that had fed on the banks of the Barampooter or the Ganges? Were all other objections to so extraordinary a supposition removed, the preservation of the hide and muscles of a dead animal, and the adhesion of the parts, while it was dragged for 2000 miles over some of the highest and most rugged mountains in the world, is too absurd to be for a moment admitted. Or shall we suppose that this carcase has been floated in by an inundation of the sea, from some tropical country now swallowed up, and of which the numerous islands of the Indian Archipelago are the remains? The heat of a tropical climate, and the putrescence naturally arising from it, would soon, independently of all other accidents, have stripped the bones of their covering. Indeed this _instantia singularis_, as in every sense it may properly be called, seems calculated for the express purpose of excluding every hypothesis but one from being employed to explain the origin of fossil bones. It not only excludes the two which have just been mentioned, but it excludes also that of Buffon, viz. that these bones are the remains of animals which lived in Siberia, when the arctic regions enjoyed a fine climate, and a temperature like that which southern Asia now possesses. From the preservation of the flesh and hide of this rhinoceros, it is plain, that when the body was buried in the earth, the climate was much the same that it is now, and the cold sufficient to resist the progress of putrefaction.

Pallas takes notice of the inconsistency of the state of this skeleton, with the hypothesis of Buffon; but he does not observe that the inconsistency is equally great between it and his own hypothesis, the importation of the fossil bones by an inundation of the sea, and that flesh or muscle must have been entirely consumed long before it could be carried by the waves to the parallel of 64°, from any climate which the rhinoceros at present inhabits.

417. The presence of petrified marine objects in places where some of the fossil bones are found, is no proof that the latter have come from the sea, though it is produced as such both by Pallas himself, and afterwards by Kirwan. These marine bodies are the shells and corals that have been parts of calcareous rocks, from which being detached by the ordinary progress of disintegration, they are now contained in the beds of sand or gravel where the animal remains are buried. They have nothing in common with these remains; they are real stones, and belong to another, and a far more remote epochs. Such objects being found in the same place where the bones lie, argues only that the strata in the higher grounds, from which the gravel has come, are calcareous; and nothing can show in a stronger light the necessity of distinguishing the different condition of fossil bodies, united by the mere circumstance of contiguity, before we draw any inference as to their having a common origin. If the marine remains were in the same condition with the bones; if they were in no respect mineralized; then the conclusion, that both had been imported by the sea, would have great probability; but without that, their present union must be held as casual, and can give no insight into the origin of either.

418. On the whole, therefore, no conclusion remains, but that these bones have belonged to species of elephants, rhinoceros, &c. which inhabited the very countries where their remains are now buried, and which could endure the severity of the Siberian climate. The rhinoceros of the Wilui certainly lived on the confines of the Polar Circle, and was exposed to the same cold while alive, by which, when dead, its body has been so long, and so curiously preserved.

These animals may also have lived occasionally farther to the south, among the valleys between the great ranges of mountains that bound Siberia on that side. Fossil bones are but rarely found in these valleys, probably because they have been washed down from thence into the plains. We must observe, too, that those animals may have migrated with the seasons, and by that means avoided the rigorous winter of the high latitudes. The dominion of man, by rendering such migration to the larger animals difficult or impossible, must have greatly changed the economy of all those tribes, and narrowed the circle of their enjoyments and existence. The heaps in which the fossil bones appear to be accumulated in particular places, especially in North America, have a great appearance of being connected with the migrations of animals, and the accidents that might bring multitudes of them into the same spot.

What holds of Siberia and of North America, is applicable, _a fortiori_, to all the other places where animal remains are found in the same condition. Thus we are carried back to a time when many larger species of animals, now entirely extinct, inhabited the earth, and when varieties of those that are at present confined to particular situations, were, either by the liberty of migration, or by their natural constitution, accommodated to all the diversities of climate. This period, though beyond the limits of ordinary chronology, is posterior to the great revolutions on the earth's surface, and the latest among geological epochs.

NOTE XXIII. § 128.

_Geology of_ KIRWAN _and_ DE LUC.

419. The two champions of the Neptunian system, who have distinguished themselves most by their hostility to Dr HUTTON, are DE LUC and KIRWAN. They have carried on their attack nearly on the same plan, and have employed against their antagonist the weapons both of theology and science. With a spirit as injurious to the dignity of religion, as to the freedom of philosophical inquiry, they have disregarded a maxim enforced by the authority of Bacon, and by all our experience of the past; "_Tanto magis hæc vanitas inhibenda venit et coërcenda, quia, ex divinorum et humanorum male-sana admixtione, non solum educitur philosophia phantastica, sed etiam religio hæretica. Itaque salutare admodum est, si mente sobriâ, fidei tantum dentur quæ fidei sunt_."[228]

[Footnote 228: The whole passage is deserving of attention, and it seems as if the prophetic spirit of Bacon had addressed it to the cosmologists of the present day. "_Pessima enim res errorem_ APOTHEOSIS, _et pro peste intellectús habenda est, si vanis accedat veneratio. Huic autan vanitati nonnulli ex modernis summâ levitate ita indulserunt, ut, in primo capitolo_ GENESEOS, _et aliis Scripturis Sacris, philosophiam naturalem fundari conati sunt:_ Inter VIVA quærentes MORTUA.--"Nov. Organum, lib. i. aphor. 65]

Proceeding, accordingly, in direct opposition to rules that, have never yet been violated with impunity, and mistaking the true object of a theory of the earth, they carry back their inquiries to a period prior to the present series of causes and effects, where, having neither experience nor analogy to direct them, they pretend to be guided by a superior light. They would have us to consider their geological speculations as a commentary on the text of MOSES; they endeavour to explain the action of creative power, and, with indiscreet curiosity, would tear off the veil which the hand of the prophet has so wisely respected. But the veil cannot be torn off, and all that is behind it must be to man as that which never has existed.

420. M. De Luc has nevertheless treated very diffusely of the history of the solar system, previous to the establishment of the present laws of nature, and has dwelt on it with great complacency, and singular minuteness of detail. His tenth letter to LA METHERIE has the following title:

"On the History of the Earth, from the time when that planet was penetrated by _light_, till the appearance of the sun; a portion of time which includes the origin of heat, and of the figure of the earth; of its primeval strata, of the ancient sea, of our continents, as the bottom of that sea, of the great chains of mountains, and of vegetation."[229]

[Footnote 229: Journal de Physique, tom. 37. (1790,) partie 2de, p. 332. As I may not have done justice to this extraordinary title, it may be right to present it in the original. "Sur l'Histoire de la TERRE, depuis que cette planette fut penetrée de LUMIERE, jusqu'à l'apparition du SOLEIL; espace de tems qui renferme les ORIGINES de la _chaleur_, et de la _figure_ de notre globe; de ses _couches primordiales_, de _l'ancienne mer_, de nos _continens_, comme fond de cette mer, de leurs grandes chaînes de _montagnes_, et de la _vegetation_."]

I must confess that I am unacquainted with every thing of this letter but the title; and could not easily be prevailed on to follow any man who professedly goes out of nature in search of knowledge; who pretends to give the history of our planetary system when there was no sun, and to enumerate the events which took place between the existence of that luminary, and the existence of light. The absurdity of such an undertaking admits of no apology; and the smile which it might excite, if addressed merely to the fancy, gives place to indignation when it assumes the air of philosophic investigation.

421. It sets, however, in a strong light, the inconsistencies that may be observed in the intellectual character of the same individual, to consider that the author of this strange and inconsistent reverie, is, nevertheless, an excellent observer, and well skilled in experimental inquiries. It will hardly be believed that he who writes the history of the earth before the formation of the sun, is versed in the principles of inductive reasoning; and that he has added much to the stock of geological knowledge, having observed accurately, and described with great perspicuity and candour. His _Lettres Physiques_ are full of valuable and just observations, though accompanied with reasonings that do not seem always entitled to the same praise; and in another work he has succeeded where many men of genius had failed, and has made considerable improvements in a branch of the mathematics, without borrowing almost any assistance from the principles of that science.[230]

[Footnote 230: Essai sur les Modifications de l'Atmosphere.]

422. Some of the same observations apply to Mr Kirwan. His Geological Essays have also for their object to explain the first origin of things; and to say that he has not succeeded, in an attempt where no man ever can succeed, implies no reproach on the execution of his work, whatever it may do on the design. We have indeed no criterion by which the execution of it can be estimated: what would in any other place be a blemish, may be here deserving of praise; and if the work is full of confusion and perplexity, these are qualities inherent in the subject which it is intended to describe. It were, no doubt, to be wished, that after emerging into the regions of day, Mr Kirwan had been as successful in copying the beauty and simplicity of nature, as in representing the disorder and inconsistency of the chaotic mass. But his cosmology is without unity in its principles, or consistency in its parts; the causes introduced, are, for the most part, such as will account for one set of appearances just as well as for another; or, if any of them is likely to prove inadequate to the effect ascribed to it, a new and arbitrary hypothesis is always ready to come to its assistance. The information given is seldom exact: a multitude of facts brought together, without the order and discussion essential to precise knowledge; and an infinity of quotations, amassed without criticism or comparison, afford proofs of extensive reading, but of the most hasty and superficial inquiry. Thus we have seen passages from ULLOA and FRISI, produced in support of opinions, which, when fairly stated, they had the most direct tendency to overthrow.

423. In one respect, the geological writings of Kirwan are far inferior to De Luc's: They are evidently the productions of a man who has not seen nature with his own eyes; who has studied mineralogy in cabinets, or in books only; but who has seldom beheld fossils in their native place. With the balance in his hand, and the external characters of WERNER in his view, he has examined minerals with diligence, and has discovered many of those marks which serve to ascertain their places, in a system of artificial arrangement. But to _reason_ and to _arrange_ are very different occupations of the mind; and a man may deserve praise as a mineralogist, who is but ill qualified for the researches of geology.

424. The same hurry and impatience are visible in the manner in which his argument against Dr Hutton is usually conducted. He has seldom been careful to make himself master of the opinions of his adversary; and what he gives as such, and directs his reasonings against, have often no resemblance to them whatsoever. Without any intention to deceive others, but deceived himself, he usually begins with misrepresenting Dr Hutton's notions, and then proceeds to the refutation of them. In this imaginary contest, it will readily be supposed, that he is in general successful: when a man has the framing both of his own argument, and that of his antagonist, he must be a very unskilful logician if he does not come off with the advantage.

425. It is but justice, however, to the Neptunists, to acknowledge, that they are not all liable to the censure of beginning their researches from a period antecedent to the existence of the laws of nature. This absurdity does not, so far as I know, infect the system of Werner. That mineralogist has not proposed to explain the first origin of things, though he has supposed, at some former period, a condition of the globe very unlike the present, viz. the entire submersion of the solid under the fluid part.

NOTE XXIV. § 129.

_System of_ BUFFON.

426. The affinity of Dr Hutton's theory to that of Buffon, is nothing more than what arises from their making use of the same agents, viz. fire and water, in producing the present condition of the earth's surface. In almost all other respects the two theories are extremely different. The order in which those agents are employed in them, is directly opposite, as has already been remarked; Buffon introducing the action of fire first, and of water only in the second place, to waste and destroy mineral bodies, and afterwards to dispose them anew, and arrange them into strata. He makes no provision for the consolidation of these strata, nor any for their angular elevation; he has no means of explaining the unstratified rocks; nor any, but one extremely imperfect, for explaining the inequalities of the earth's surface.

Again, Buffon mistook, in some degree, the true object of a theory of the earth; and though he did not go back, like the geologists just named, to a time when the laws of nature were not fully established, he begins from a condition of things too unlike the present to be the basis of any rational speculation. He does not, indeed, undertake to examine the state of our planetary system before the sun existed; for from such extravagance, even when most disposed to indulge his fancy, he would surely have revolted. But he treats of the world, when the earth and the planets had just ceased to be a part of the sun, and were newly detached from the body of that luminary.[231]

[Footnote 231: According to Buffon, the granite is the true solar matter, unchanged but by its congelation.]

This hypothesis concerning the origin of the planets, contrived chiefly to account for the circumstance of their motion being all in the same direction, and in other respects not only unsupported, but even inconsistent with the principle of gravitation, has nothing in common with a theory, confined as Dr Hutton's is, within the field which must for ever bound our inquiries, and not venturing to speculate about the earth, when in a condition totally different from the present.

427. In what relates to the future, the two systems are not more like than in what relates to the past Buffon represents the cooling of our planet, and its loss of heat, as a process continually advancing, and which has no limit, but the final extinction of life and motion over all the surface, and through all the interior, of the earth. The death of nature herself is the distant but gloomy object that terminates our view, and reminds us of the wild fictions of the Scandinavian mythology, according to which, _annihilation_ is at last to extend its empire even to the gods. This dismal and unphilosophic vision was unworthy of the genius of Buffon, and wonderfully ill suited to the elegance and extent of his understanding. It forms a complete contrast to the theory of Dr Hutton, where nothing is to be seen beyond the continuation of the present order; where no latent seed of evil threatens final destruction to the whole; and where the movements are so perfect, that they can never terminate of themselves. This is surely a view of the world more suited to the dignity of NATURE, and the wisdom of its AUTHOR, than has yet been offered by any other system of cosmology.

428. I have often quoted Buffon in, the course of these _Illustrations_, and most commonly for the purpose of combating his opinions; but I am very sensible, nevertheless, of the obligations under which he has laid all the sciences connected with the natural history of the earth.

The extent and variety of his knowledge, the justness of his reasonings, the greatness of his views, his correct taste, and manly eloquence, qualified him, better, perhaps, than any other individual, to compose the History of Nature. The errors into which he Has fallen, are almost all the unavoidable consequences of the circumstances in which he was placed; and if their amount is estimated by the proportion that they bear to the general excellence of the work, they will be reckoned but of small account. Buffon began to write when many parts of natural history had made but little progress; when the quantity of authentic information was small, and when scientific and correct description was hardly to be found. Many of the greatest and most important facts in geology were quite unknown, and scarcely any part of the mineral kingdom had been accurately surveyed; and, with such materials as this state of things afforded, it is not wonderful if some parts of the edifice he erected have not proved so solid and durable as the rest. Had he appeared somewhat later; had he been farther removed from the time when reasonings _a priori_ usurped the place of induction; and had he been as willing to correct the errors into which he had been betrayed by imperfect information, as he was ingenious in defending them, his work would probably have reached as great perfection, as it is given for any thing without the sphere of the accurate sciences to attain. If he had examined the natural history of the earth more with his own eyes, and been as careful to delineate it with fidelity as force; if he had listened with greater care to the philosophers around him; had he attended to the demonstrations of NEWTON more, and despised the arrangements of LINNÆUS less; he would have produced a work, as singular for its truth as for its beauty, and would have gone near to merit the eulogy pronounced by the enthusiasm of his countrymen, MAJESTATI NATURÆ PAR INGENIUM.

NOTE XXV. § 130.

_Figure of the Earth._

429. That the earth is a spheroidal body, compressed at the poles, or elevated at the equator, is a fact established by many accurate experiments; and though these experiments do not exactly coincide, as to the degree of oblateness which they give to that spheroid, they agree sufficiently to put it beyond all dispute, that the earth, though solid, has nearly the same figure which it would assume if fluid, in consequence of its rotation on its axis.

Now, it is not at all obvious, to what physical cause this phenomenon is to be ascribed. The earth, as it exists at present, has none of the conditions that render the assumption of the figure of equilibrium in any way necessary to it. Constituted as it is, its parts cohere with forces incomparably too great to obey the laws of statical pressure, or to assume any one figure rather than another, on account of the centrifugal tendency which results from its revolution on its axis. There is no necessity that its superficies should be every where level, or perpendicular to the direction of gravity, nor that every two columns, standing on the same base, any where within it, and reaching from thence to any two points of the surface, should be of such weights as precisely to balance one another. Neither of these, indeed, is at all conformable to fact. They are, however, the very suppositions on which the determination of the spheroid of equilibrium is founded; and as they certainly do in no degree belong to the earth, it seems strange that the result deduced from them should be in any way applicable to it. This coincidence remains, therefore, to be explained; and it must greatly enhance the merit of any geological system, if it can connect this great and enigmatical phenomenon with the other facts in the natural history of the earth.

430. To establish such a connection, has, accordingly, been a favourite object with geologists, whether they have embraced the Neptunian or Volcanic theory: both have thought that they were entitled to suppose the primeval fluidity of the globe, the one by water, and the other by fire; and in whatsoever way that fluidity was produced, the result of it could be no other than the spheroidal figure of the whole mass, agreeably to the laws of hydrostatics. If in this fluid state the earth was homogeneous, the spheroid would be accurately elliptical, and the compression at the poles would be 1/230 of the radius of the equator; if the fluid was denser toward the centre, the flattening would be less: and in either case, the body, as it acquired solidity, may be supposed to have retained its spheroidal figure with little variation. But though the fluidity of the earth will account for the phenomenon of its oblate figure, it may reasonably be questioned, whether this fluidity can be admitted, in consistency with other appearances. According to what is established above, none of the appearances in the mineral kingdom indicate more than a partial fluidity in any former condition of the earth. The present strata, made up as they are of the ruins of former strata, though softened by heat, have not been rendered fluid by it, and have even possessed their softness in parts, and in succession, not altogether, nor at the same time.

The unstratified, and more crystallized substances, were cast in the bosom of others, which were solid at the time when they were fluid. In all this, therefore, there is no indication of a fluidity prevailing through the whole mass, or even over the whole surface of the earth, and therefore nothing that can explain the spheroidal figure which it has acquired. The supposition, then, of the entire body of the earth, or even of its external crust, having been fluid, though it might account for the compression at the poles, does not connect that fact with the other facts in the natural history of the globe, and fails, therefore, in the point most essential to a theory. It is liable, also, to other objections, whether it be conceived to have proceeded from fire or from water; whether it has happened on the principles of Buffon or of Werner.

431. First, let us suppose that the fluidity of the earth, or of the external crust of it, at least to a certain depth, proceeded from a solution of the whole in the waters of the ocean; and, waving all the objections that have been stated to this hypothesis, on account of the absolute insolubility of many mineral substances in water, let us suppose them all soluble in a certain degree, and let us compute the quantity of the menstruum, which, on the suppositions most favourable to the system, must have been required to this great geologico-chemical operation.

The siliceous earth, though not soluble in water _per se_, yet, after being dissolved in that fluid by means of an alkali, was found by Dr Black, in his analysis of the Geyser water, to remain suspended in a quantity of water, between 500 and 1000 times its own weight. This is one of the facts most favourable to the Neptunian theory; and that every advantage may be given to that theory, we shall take the least of the numbers just mentioned, and suppose that siliceous earth may be dissolved or suspended in 500 times its weight of water.

Taking this for the extreme degree of insolubility of mineral substances, (though there are many of which the insolubility is absolute, or, to speak in the language of calculation, infinitely great,) we may suppose the insolubility of all the rest, or the quantities of water in which they are dissolved, to be ranged in a descending scale from 500 to 0, the extreme degree of deliquescence. Then, taking the arithmetical mean between these extremes, it will give us 250, as the proportion of water in which mineral substances may at an average be dissolved. But this average is much less than the truth; for the quantity of siliceous earth is great in comparison of any of the rest, and the mineral substances that are extremely soluble in water are but in a small quantity; therefore, when we suppose mineral bodies, at a medium, to be soluble in 250 times their own weight of water, we make a supposition extremely favourable to the Neptunian system.

432. This is the proportion between the _weight_ of the solvent, and of the substances held in solution: to have the proportion of their _bulks_, we may suppose the specific gravity of mineral bodies in general to be to that of water as 5 to 2, and then we have the ratio of bulks, that of 250 × 5 to 2 × 1, or of 625 to 1. It follows, then, that minerals in general cannot be supposed soluble in less than 625 times their bulk of water.

433. Again, it must be allowed to the Neptunists, that the fluidity of the whole earth is not necessary to account for its assuming the spheroidal figure. It is sufficient if the whole of that crust or shell of matter was fluid, which is contained between the actual surface of the terrestrial spheroid, and the surface of the sphere inscribed within it; that is, of the sphere which has for its diameter the polar axis of the earth. The whole of the minerals which compose this shell, must at least have been dissolved in water, and have formed the chaotic mass of Mr Kirwan. The volume of the water required for this was not less than 625 times the bulk of the spheroidal shell that has just been mentioned.

But, assuming the difference between the polar axis and the equatorial diameter to be 1/300 of the latter, which is the supposition most agreeable to the phenomena, it is easy to show that the magnitude of the above spheroidal shell, or the difference between the solid content of the earth, and the sphere inscribed in it, is greater than 1/151 and less than 1/150 of the whole earth; so that the earth is less than 151 times the spheroidal shell.

The volume of the water, therefore, necessary to hold in solution the materials of this shell, is to the volume of the whole earth as 625 to 151, or in a greater ratio than that of four to one: and such, therefore, at the very least, is the quantity of water which Mr Kirwan supposes, after it ceased to act in its chemical capacity, to have retired into caverns in the interior of the earth. Thus the Neptunists, in their account of the spheroidal figure of the earth, are reduced to a cruel dilemma, and are forced to choose between a physical and a mathematical impossibility.

If we would inquire whether the opinion of the igneous origin of minerals, as commonly received by the Vulcanists, is capable of affording a better solution of this difficulty, the theory of M. de Buffon is the first that presents itself.

434. That philosopher considers the existence of the spheroidal figure as a proof that the whole of the earth must have been originally fluid; and as the fluidity of the whole can only be ascribed to fusion, he has supposed that the earth was originally a mass of melted matter struck off from the sun by the collision of a comet; and that this mass, when made to revolve on its axis, put on a spheroidal figure, which it has retained, though now cooled down to congelation.

This system need not be considered in detail; the foundation of it is laid in such defiance of the principles of geometry and mechanics, that the architect, notwithstanding all the fertility of his invention, and all the resources of his genius, was never able to give any solidity to the structure.

But it will be said, that we may take a part of the system, without venturing on the whole, and may suppose that the earth, or at least the external crust of it, has been fluid by fire, though we do not inquire into the cause of this fire, or into the manner in which it was produced.

It is indeed true, that, when this is done, we have not the same sort of absurdity to encounter that we met with in the Neptunian system, and that the Volcanic theory does not, like it, come into direct collision with an axiom of geometry. There are, nevertheless, great objections to it; for though all the phenomena of the mineral kingdom attest a fluidity of igneous origin, yet it is a fluidity that was never more than partial; and though it has been over all the earth, has been over it in succession only. Besides, we are not entitled to assume the existence, and again the disappearance of such a great quantity of heat, without assigning some cause for the change.

435. Since, then, neither the hypothesis of the Neptunists or the Vulcanists, affords any good explanation of the figure of the earth, or such a one as can connect it with the other appearances in its natural history, it remains to inquire, whether the system that supposes a partial and successive fluidity, like Dr Hutton's, has any resource for explaining this great phenomenon.

Of this subject Dr Hutton has not treated; and when I was first made acquainted with his system, it appeared to me a very serious objection to it, that it did not profess to give an explanation of so important a fact as the oblate figure of the earth. On considering the matter more closely, however, I found that there were principles contained in it from which a very satisfactory solution (and, I think, the only satisfactory solution) of that difficulty might be deduced. This solution I shall endeavour to explain, in as far, at least, as is necessary for the purpose of general illustration.

It is laid down in Dr Hutton's theory, that the surface of the earth is perpetually changed by the _detritus_ of the land; and that from the materials thus afforded, new horizontal strata are perpetually formed at the bottom of the sea. If this be true, and if the alternations of decay and renovation have been often repeated, it is certain, that the figure of the earth, whatever it may have originally been, must be brought at length to coincide with the spheroid of equilibrium.

436. Here it is necessary to remark, that the expressions, _figure of the earth_, and _surface of the earth_ are each of them occasionally taken in two different senses.

The surface of the earth, in its most obvious sense, is that which bounds the whole earth, and includes all its inequalities; it is a surface extremely irregular, rising to the tops of the mountains, descending to the bottoms of the valleys, and having the continuity of its curvature often interrupted, or suddenly changed. This may be called the _actual_ surface, and the figure bounded by it, the _actual_ figure, of the earth.

The surface of the earth, in another sense, is one that is every where horizontal, and is the same which water assumes when at rest.

This superficies is determined by the circumstance of its being constantly perpendicular to the direction of gravity; it is the surface marked out by levelling, and may be supposed to be continued from the sea, through the interior of the land, till it meet the sea again. The figure bounded by this horizontal surface, may properly be called the _statical_ figure of the earth.

When it is said that the figure of the earth is an oblate spheroid, it is the statical, not the actual figure which is meant; and the degrees of the meridian which astronomers measure, are also referred to the superficies of the former.

437. Suppose now a body like the earth, but with its actual figure infinitely more irregular, having a sea circumfused around it, the water will descend into the lowest situations, and will so arrange itself, that its surface shall be perpendicular every where to the plumb-line, or to the direction of gravity, in which state only it can remain at rest. The figure of the superficies which the sea must thus take will be of a continuous curvature, and will return into itself; though it may, if the actual figure is very irregular, be far either from a sphere or a spheroid. If, however, we suppose the solid parts of this mass subject to be dissolved or worn away, and carried down to the ocean, there will be a tendency to give to the whole body the same figure that it would have assumed, if it had been entirely fluid, and subject to the laws of hydrostatics. This tendency is the result of two principles.

438. Let us suppose the body just described to have no rotation, so that the particles of it are actuated only by the forces of cohesion and of attraction.

It is then clear, that every particle taken away by attrition from the parts above the level of the sea, and deposited under the surface of it, makes the general figure more compact, bringing the remoter parts nearer to the centre of gravity of the whole; so that, in time, if the body is homogeneous, all the points of the surface will become equally distant from that centre. Thus the _actual_ figure changes continually, and approaches nearer to the _statical_.

While this change is going forward in the actual figure, there is another produced on the statical, that tends very much to accelerate the final coincidence, of the two.

The effect of the inequalities of the land, that rise above the horizontal surface, is, by their attraction, to render the parts of that surface immediately under them, more convex, _cæteris paribus_, than the rest. Again, where there are parts of extraordinary depth in the sea, that is, where the solid and denser parts are far removed from the surface of the ocean, the curvature of the superficies of the sea is thereby diminished, and that superficies is rendered less convex than it would be if the sea were shallower. These propositions are both capable of strict mathematical demonstration. Hence the taking away of any particle of matter from the top of a mountain tends to diminish the curvature of the horizontal surface under the mountain, where it is greatest; and the deposition of the same particle at the bottom of the sea, tends to increase the curvature of this superficies where it is least. The general tendency, therefore, being to increase the curvature where it is least, and to diminish it where it is greatest, must be to bring about an uniform curvature throughout, that is, a spherical figure. Thus, by the waste and subsequent stratification of the land, the direction of gravity is continually altered; it is more and more concentrated, and the figure brought nearer to that which a fluid would assume.