Enfin, paroît du lieu le curé refpectable, On franchit les forêts, les taillis, les buiffons, O riant Chanonat! fortuné féjour ! Je croirai voir encor ces beaux lieux, ce beau jour, Enfant, je me mêlois aux enfans du village!' p. 125—9. Upon the whole, we think this poem decidedly inferior, in point of intereft and beauty, to either of M. de Lille's performances upon rural fubjects. His diction and verfification, indeed, are almost uniformly harmonious and elegant: but he wants fimplicity and force for the higher departments of poetry, and commonly falls into a ftyle of declamatory exaggeration and diforder, whenever he abandons his old and appropriate fubjects. Les Jardins,' we have no doubt, will long be admired over all Europe: but M. de Lille muft not expect to go down to pofterity as the poet of the Revolution. ART. III. Traité de Mineralogie. Par le Citoyen Haiiy, en Cinq Volumes, dont un contient 86 Planches. à Paris, an 10, (1801.) FROM ROM its intimate dependence on chemistry, mineralogy has profited extenfively by the recent difcoveries in that fcience. The compofition of minerals has been illuftrated by ingenious and delicate analyfes, and the number of fimple fubfiances has been increafed by the difcovery of new carths and new metals. The fame fame accuracy of refearch that has enlarged the number of com ponents, has diminished the estimated number of compounded bodies, by proving the frivolity of many fuperficial diftinctions. which had been regarded as fpecific, and by eftablishing precife criteria of effential differences. The advance and amplification of the fcience has neceffarily rendered every fyftematic work obfolere. The efforts by which the ftrenuous mind of Linnæus endeavoured to pierce the darknefs in which mineralogy was previoufly enveloped, now appear ill directed; and though the fagacity of Cronstedt, and the accutenefs of Wallerius, may continue to claim our admiration, he who would attempt to reconcile the modern discoveries with their fyftems or arrangement, would find himself involved in the most inextricable confufion. Yet, fince their time, almoft all the fyftems of mineralogy which have iffued from the prefs have concurred in retaining the greater part of their defects, and contributed to perpetuate error by vicious arrangement and inaccurate defcription. The Germans have, for the most part, contented themselves with pillaging and mutilating the lectures of Werner; and the other nations of Europe have generally been satisfied with doing into their refpective languages the Teutonic lucubrations. By this tranfmutation, we cannot fay that they have generally improved. Diffufion has become prolixity, obfcurity unintelligible, the old blunders have been religioufly retained, and. an innumerable hoft of new abfurdities has been engendered. A treatise on mineralogy, exhibiting a correct view of the prefent ftate of our knowledge, was therefore a moft important defideratum in this department of fcience; which the prefent pubdication of M. Haüy has done much to fupply. His theory of cryftallization has been in fome degree previously communicated to the public by his papers in the Journal des Mines; and its fingular ingenuity and utility must have been univerfally perceived. The fame theory is now prefented in the most complete form; enriched with every fubordinate illuftration; applied to the inveftigation and defcription of minerals with infinite dexterity; and combined with a judicious felection of all the mineralogical facts which have been previously published, or that may have occurred to his own obfervation, or to his colleagues in the Ecole des Mines; from whofe generous contributions, and industrious exertions, his volumes have derived additional value. From these extensive investigations has refulted a treatise, in which mineralogy is exhibited at least in a new form, and a fyttem is delivered, differing from all that have preceded it, in general arrangement, individual divifion, and nomenclature. Before we can determine, whether thefe extraordinary innovations are entitled entitled to our unqualified approbation, it is neceffary to inquire, whether they were actually called for by the errors of the prevailing fyftems, and whether they furnish proper remedies for acknowledged defects. From the uncertainty and obfcurity attending every infant fcience, the determination of the mineralogical fpecies has always been a subject of difpute. The operation of no general principle being recognised, varieties have been wantonly conftituted into species from the moft frivolous and fuperficial differences; and the moft oppofite and difcordant fubftances have been violently united from fancied fimilitudes. Though the prodigious improvements of analytic chemistry have thrown a strong and fteady light on fome of the moft obfcure branches of mineralogy, its affistance is not adequate to the determination of every ambiguous point; and chemistry itself is even yet too much in its infancy, for its decifions to be always confidered as an authority from which there is no appeal. By the means of analysis, the combinations of earths and acids have been fully disclosed; the mixtures of metals, and the refults of their union with acids, gafes, and fulphur, have been fatisfactorily developed: but the combinations of earths with earths, yield refults nearly fimilar from fubftances of the moft ftriking diffimilarity. In mineralogical character, and in the analysis of different fpecimens of the fame mineral, as far as other tefts can determine its identity, a variety of compofition has been detected no lefs mortifying than unexpected. Till the complicated operation of affinities is more perfectly understood, and we have learnt to correct by compenfation the errors they neceffarily create, we muft not implicitly rely on indications that may be fallacious. We must endeavour, therefore, to find fome other criteria that may confirm the authority of analysis where its march is affured, and its refults fatisfactory, and may ferve as guides where its fteps are faltering and irregular. The precifion of cryftalline forms has not escaped the attention of mineralogists; and they have not been wanting in their endeavours to avail themselves of it in diftinguishing fpecies. Linnæus, who firft engaged in this inquiry, was followed by Bergman, whofe labours tended greatly to its advancement; but it was referved for Romé de Lille to enlarge the hitherto narrow limits of this branch of fcience, by estimating angles with precifion, and deducing all crystals from the modification of a few primitive forms. Though often fuccessful in explaining the origin of the most complex fecondary forms, by means of the imaginary truncations and bevellings of a fimple folid, the immense duftry and great fagacity of this laft inquirer were frequently baffled, baffled, and he was reluctantly obliged to fuppofe that fome minerals poffeffed more than one original form, from which their modifications were deduced. However neceffary fuch a conclufion might appear, it was evidently inadmiffible, without fuppofing a deviation from that uniformity which is invariably found in the works of nature; and even if the fyftem of Romé de Lifle had been refcued from this mortifying conceffion, it would ftill have been wholly unfit for the determination of minerals by their cryftals, as a few fimple folids would have been efteemed the common origin of numerous fubftances moft effentially diftinct. It was first observed by the truly ingenious and scientific Mr Kier in his Chemical Dictionary, and afterwards repeated by Bergman in his Opufcula, that the fragments of calcareous Spar were invariably rhomboidal. Thefe philofophers, however, pushed their inquiry but little farther. About the fame time, though without being informed of their previous obfervations, the fame fact occurred to M. Haüy. Upon his inquiring mind, it feems to have made a more powerful impreffion, and he immediately extended the investigation. He found that every variety of calcareous fpar yielded, on breaking, rhomboidal fragments, and was only divifible in directions parallel to the fides of these rhomboids; and that, from whichever of the diverfified chryftals of this fubftance the rhomboid was derived, its angles were invariably the fame. He found that fluate of lime yielded, by mechanical divifion, a nucleus which was invariably a regular octohadron. That from fulphuret of lead, he always obtained a cube; from fulphuret of zinc, a dodecahadron; and that from every chryftal fufceptible of mechanical divifion, a folid might be extracted that was common to all the chryftallized varieties of that fubftance. In many cafes, the divifion was performed with accuracy and facility; the surfaces of the folid obtained were even, and fometimes brilliant; parallel to its fides, it was again divifible with equal eafe; and folids perfectly fimilar were generated, till they became fo fmall as to elude the obfervation of our fenses: but every attempt to divide, except in directions parallel to the fides originally obtained, was ineffectual, or produced only an irregular fracture. He alfo found, that in many inftances where the attraction of aggregation was fo powerful as to defy his efforts to extract this nucleus perfect on every fide, it was ftill capable of being developed, in certain directions, with fufficient accuracy to enable him to detect its form, and appreciate its angles. By a copious and direct induction, he was enabled at last to afcertain this important fact, that every mineral poffeffes a form, on which all its diverfities of cryftallization are dependent; fince this form, form, and this only, can be extracted with equal facility from them all, however they may be difguifed by apparent diffimilarity. The cryftals of minerals not unfrequently prefented this form; and all deviations from it appeared to have been produced by the operation of laws that regularly influenced the aggregation of the cryftalline particles: and fince, after pufhing divifion as far as our fenfes can follow its effects, we find the form of the folids obtained to be mathematically the fame, M. Haüy conceived himself authorised to confider this refult as final, or ultimate, in relation to our faculties; and bestowed on the nucleus the denomination of the integral molecule. When the form of the cryftal is the fame as that of the molecule, each crystal may be confidered as an accumulation of molecules, arranged by fome fpecies of polarity. But though the external form of the cryftal fometimes correfponds with that of the nucleus, it more frequently differs from it, and fometimes fo remarkably, that it appears impoffible to devife any laws by the operation of which it could be obtained. Though the nature of such laws may remain for ever unknown, yet it is important to trace their effects, and to devife fome mode of explaining their operation and refults, that may not be at variance with the first principles of the fcience it is intended to elucidate. Though the hypothefis of truncations readily explains almoft any appearance, accommodates itfelf with wonderful flexibility to difficulties, and introduces confiderable facility into the expreffion of even the more complicated cryftalline forms, it is obviously inadmiffible in any fyftem that aims at an approximation to truth; becaufe it involves an idea of diminution and fubtraction, directly contrary to the most established principle of cryftallization. It renders it neceffary to fuppofe, that the fecondary forms of cryftals are generated, by cutting large portions from the surface of a primitive folid. But cryftallization never recedes. It produces the fecondary forms, not by abftracting any portion of the nucleus, but by accumulating additional molecules on particular parts of it; and on this most important diftinction is founded the explication which M. Hauy has devifed. If their arrangement continue undisturbed, additional molecules can only increase the magnitude of the folid. Each one will be deposited in order by the fide of another, till their united numbers form a coat extending over one fide of the cryftal. But if the next coat of molecules, inftead of covering the whole plane, leave round the edges the breadth of one molecule uncovered, there will then be placed on the primitive cryftal a thin plane, fomewhat lefs in dimenfions than the one on which it is fuperimpofed. Let the fame law, which ordered this decreafe, continue to ope rate, |