thofe of all who engage in theological controverfy, which is emimently useful in roufing men to the utmost exertion of their faculties, he is promoting his own excellent purposes, and providing for the prevalence of truth, in his own due time; and in this general profpect we ought all equally to rejoice.

"It becomes us, however, to confider, that they only will be entitled to praise, who join in carrying on the defigns of Providence with right views of their own; who are actuated by a real love of truth, and alfo by that candour and benevolence, which a fense of our common difficulties in the investigation of truth most effectually infpires. A man who has never changed an opinion, cannot have much feeling of this difficulty; and therefore cannot be expected to have much candour, unless his disposition be uncommonly excellent. I ought to have more candour than many others, because I have felt more than many can pretend to have done, the force of those obftacles which retard our progress in the fearch of truth.

With much tranquillity, a tranquillity acquired by habit, but more approaching to a pleafing alacrity, than to any unealy apprehenfion, I fhall wait the iffue of the prefent controverfy; freely res tracting whatever I fhall be found to have advanced with too little confideration; moderating any thing on which I fhall appear to have laid too much stress, and urging with the greatest freedom every new argument or illuftration that may occur to me, till I fhall have nothing of confequence to alledge. After this I fhall no longer reply to particular opponents, but content myself with making fuch corrections and improvements either in my Hiftory, or my intended View of the doctrine of the firft ages of the cbriftian church, concerning the perfon of Chrift, as I may fee neceffary; fubmitting every thing to the judgment of thofe who may think proper to give any attention to the fubject.'

It feldom happens, whether we chufe to afcribe the phenomenon to nature or to habit,that the fame mind, which has obtained important fuccefs in the purfuit of fpeculative science, is qualified to produce the beauties of the imagination. Accordingly, though, from the folidity of his judgment, we are fatisfied that our author is capable of exhibiting a much more polished and regular work, than any he has yet given to the public; yet certain it is, that in aiming at the height of fublimity, or the finer touches of paffion, he would fail in the attempt. But there is an interefting language, that comes from the heart, and with which the fancy of the writer has nothing to do; and of this the extract we have produced indifputably shows Dr. Priestley to be master.

M

FOREIGN

LITERATURE.

FOREIGN

ART. XIII. Hiftoire Naturelle des Mineraux. Par M. le Comte de Buffon, 2 tom. 4to. Paris, 1783.

THIS

Buffon's Natural History of Minerals.

Every

HIS work is well calculated to excite curiofity. one who has enquired, however fuperficially, concerning the productions of the material world, must be anxious. to learn how this venerable hiftorian of Nature has found the means of adapting his eloquence and his theories to the minutiæ of mineralogy; for in his former volumes he had treated most of the general topics which alone would feem to allow his talents for fine writings much fcope. Let us see how he has found or created space for the exertion of his genius. He begins with confidering the cause of cryftallization; or, as he denominates it, la figuration, a term new alike to the French and the English languages, and we think unneceffary, fince it is not more expreffive than the old one. And here, in the very front of his work, he again introduces to thy notice, be not startled, good reader! his organic molecules, or, as he now frequently chufes to call them, organic parts. He divides fofils into three claffes, one comprehending fuch products of the primitive fire as have not changed their nature, viz. roc vif, quartz, jafper, feld-fpath, fchoerl, mica, fandftone, porphyry, granite, with fuch fubftances of original or fecondary formation as are not calcinable; and befides these, vitrifiable fand, clay, fchift, flate, and whatever comes from the decompofition of primitive matters attenuated, diffolved, or any way altered by water: another containing bodies that have a fecond time undergone the action of fire: thefe two claffes belong to inorganic nature (la nature brute) as they feldom or never bear any marks of organization; and a third and laft clafs comprizing calcinable fubftances, vegetable earth, and every thing formed of the fpoils of animals and vegetables by means of water; thefe are, the feveral modifications of calcareous earth, that thin ftratum of mould which almost every where covers the furface of the globe; as alfo peat, foffil-wood, coal. In this clafs, obferves the author, may be perceived every gradation between brute matter and organized fubftances; this intermediate matter, partly brute and partly organic, ferves alike for the productions of Nature in her two empires of life and death, for vegetable mould and calcinable bodies contain far more organic particles than thofe fubftances which have been produced or changed by fire; thefe particles, ever active, have made Heep impreffions upon paffive matter; they have elabo

rated

rated all its furfaces, and fometimes penetrated into it. Wa ter developes, dilutes, tranfports and depofits these organic elements on brute matter: thus moft regular foffils owe their form to the combination of this active matter with the water, which conveys it. The productions of organized Nature, which, in the ftate of life and vegetation, reprefent her power and conftitute the ornament of the earth, continue after death to be the nobleft part of formlefs Nature; the spoils of animals and vegetables preferve their active organic molecules which impart to paffive matter the first rudiments of organization by bestowing on it an external figure. Every foffil form has been elaborated either by thefe molecules proceeding from decayed organized bodies, or by thofe which exifted before their formation. Thus minerals, with a regular shape, are more or lefs connected with organic Nature, and there exift no fubftances totally brute, except those which beat no mark of cryftallization, for like every other property of matter, organization has its fhades and degrees, of which the most general and moft diftinct characters, as well as the most evident refults, are life in animals, vegetation in plants, and figuration in minerals."

After having made fome remarks on the growth of organized bodies by intus-fufception, and the enlargement of foffils by the juxta-pofition of regularly-fhaped laminæ infinitely small and flender, he obferves that the formation of each thin lamina. is a true lineament of organization which cannot be traced on the conftituent parts of each mineral but by organic elements. Is it not likely, he continues, that Nature, which fo often works matter in its three dimenfions at once, fhould ftill more frequently labour it in two only, employing but a few organic molecules, which, being in this cafe overburthened with brute matter, can arrange the furface only, without being able to penetrate inter-> nally and elaborate the bafis, and confequently to inform the mafs either with vegetable or animal life. And although this tafk be fimpler than the former, fince it is more eafy to fineer (effleurer, how fhall we translate this word?) matter in two dimenfions than to work it in all at once, yet Nature employs the fame means and the fame agents. The penetrating power of attraction, combined with the expanfive force of heat, produces the organic molecules, and fets brute matter in motion, determining it to fuch or fuch a form, as well internally as externally, when it is wrought in all dimenfions at the fame time; and thus are formed the germs of animals and vegetables: but as in foffils every lamina is wrought but in two dimenfions by a certain pumber of molecules, its furface only can receive any regular thape, which ENG. REV. Jan. 1785. Vol. V.

E

elabo

elaboration of shape is undeniably a first line of organization, as it is the only one obfervable in foffils; now every atom having once received this figure, they all are brought together by dint of their refpective, affinity, which depends more on shape than on mafs; thefe atoms having all the fame form foon come to conftitute a fenfible body, ftill of like fhape as the prifms of cryftal, the rhombs of calcarious fpar, the cubes of fea falt, &c."

Such is this theory of cryftallization; and while we admire the author's addrefs in accommodating the notions, or rather the terms (for it may be doubted whether all his terms reprefent ideas) of his theories refpecting animals and vegetables to the foffil kingdom, we fhall not affect to examine his opinions logically; we fhall leave it to his readers to enquire what experimental proof he can adduce of the prefence of organic molecules in cryftals, and of their abfence from the fame body in a rude fhape: we need not take the trouble to remind them how experience has fhewn that almoft any substance may be obtained in a regular form by proper management. Such confiderations ought to be as far removed from the perufal of M. Buffon's theories as of poeti cal fictions.

After this view of the general theory, let us take a short furvey of the moft remarkable particulars. As the author proposes to confider foffils in the order of their antiquity, his notions concerning the formation of the earth lead him, as we have already ftated, to treat first of the products of the ori ginal fufion, and then of its various modifications in fucceffion. The glaffy fracture, hardnefs and infufibility of quartz fhew it to have been the primordial glass, and to be the matter of which the folid nucleus of the earth confists; but as it cooled it must have exfoliated in and become

cracked and tarnifhed on the furface, hence mica; iron the moft refractory of the metals, next was precipitated from the atmosphere, and occupied fome of thofe cavities which were formed on the furface of the cooling mafs; this metal, difcolouring the primitive quartz, formed jafper, as alfo feldfpath* fchoerls, which have in like manner quartz for their bafis, but were more modified by the condensed impurizies.

Quartz is found in three different ftates; firft, in large maffes, hard, and without moisture, produced by the primitive vitrification. Secondly, in fmall pieces that flew off in the first æra, during refrigeration; in this form it enters in

* See his Epoques de la Nature.

to the compofition of granit, &c.; and, thirdly, as altered by vapours of the earth, or the infiltration of water.. Primitive quartz is dry to the touch, that which is altered is fofter, and what ferves as a matrix for metals is generally un&tuous.

Jafper differs from quartz in being more opake, and having a fracture lefs fmooth is found more rarely, because metals exift in few places only. Account of a curious mountain in Lorrain, which exhibits jafper running in undulating veins among quartz; thefe veins reprefent the funnels through which the metallic exhalations arofe, for they are of various colours, and the quartz feems to pafs gradually into jafper.

1.

Mica is cotemporary with the two former primitive glaffes, but is never found in large maffes. Talc differs from it in being fofter to the touch, and in being found in larger laminæ, and fometimes in ftrata. All talc, however, was once mica; it has only been more expofed to the action of water, whence its unctuofity. Mica formed originally the external cruft of the globe, under which quartz and jafper were annealed, and which being itself fuddenly expofed to the influence of cold, was fplit into fpangles.

Feld-fpath and fchoerl, continuing longer in a state of fufion, received more heterogeneous fubftances, fome of which were faline, as they condenfed; whence their fufibility. The fracture of the former fpathaceous, it is no where found in great maffes. Schoerl is itfelf a feld-spath, in which quartz the common base is mixed with more extraneous matters.

We have, in the next place, an enumeration of the compounds formed by these original glaffes. Porphyry is faid to confift only of jafper, feld-fpath, and fchoerl. It is compared with granit; notice is taken of the fuperior duration of monuments of porphyry above thofe of granit. A defcrip. tion is given of the various forts, together with fevere ftrictures on Mr. Ferber's enumeration of thofe of Italy. A distinction is made between porphyries of primitive and secondary formation.

M. Buffon attempts to explain the formation of granit from the hypothefes already mentioned, together with the fufibility of felt-fpath and schoerl. When the fcales and fragments of the first glaffes had exfoliated, and lay loofe upon the furface in a folid, or nearly folid ftate, the two laft ran between their interftices, and bound them together like a cement. In this article a curious obfervation is brought forward, which, according to the author, has been entirely neglected by other mineralogifts, and which, it must be own-, E 2 ed,