sense may be misled by systems. Seduced by his aquatic fyftem, and by the productive powers of water, he at laft feems to have really perfuaded him-self that men might have been originally fish. To fupport his fyftem Mr. de Buffon afferts, that all the highest chains of mountains are fituated towards the line, and in the direction of the equator, or at leaft deviating only 23 degrees from it; and, to confirm it, caufed maps to be drawn by Mr. Buache. These are made for the fyftem, and not for the globe. In fact, as the Abbé Rofier remarks, fo far from the highest eminences of the earth lying near the equator, the moft immenfe known plains are fituated either under it, or on each fide of it. In Africa the deferts of Nigritia and fuperior Ethiopia, the fandy plains of Caffreria, of Monemugi, and Zanguebar; from its eastern coafts to the Sunda Iflands, a fea of 1500 leagues; from the Moluccos and New Guinea to Peru, an ocean of 3000 leagues; and another from America to the western coafts of Africa, occupy the torrid zone. The two high mountains of Cimborafo and of Pitchinqua under the lineare only an exception without confequence, as the great chain of the Andes, instead of running in its direction, ftretch almost directly fouth. The immenfe plain between the Orinoco and the river of Amazons is a further contradiction to this affertion. All the great chains moreover diverge from the equator either to the north east or to the fouth-weft. If it is admitted that the axis of the globe was inclined at the deluge, many great chains will then appear to have been, at the first creation, either under the line then concen- trical with the zodiac, or not more than 25 degrees diverged from its direc-tion. In that cafe, the prefent formation of mountains would not fo greatly militate against the fuppofition of this great naturalift, that the centrifugal force muft not only have elevated towards the equator the general furface of the earth, but have occafioned its highest protuberances to run in that direction. According to my ideas, however, as the greatest part of the furface of the earth was overturned and dislocated at the deluge, very little of this former very probable arrangement can now be expected to appear. In fact, we must always force the real truth to bend it to this fuppofition. Even by changing the pofition of the poles 23 degrees, the Alps, mount Krapack, Krapack, the Caucafus would ftill be found too diftant; whilft the high mountains of Canada and Norway, the elevated platform of Siberia, and. of the defert of Chamo, would yet fwerve ftill more from the equator. In his first writings Mr. de Buffon, with much more ingenuity, has destined the highest mountains, whose greatest chains cut the equator obliquely in diverging 25 degrees, to be the counterpoifes which balance the two continents. Thus we fee does this philofopher forcibly bend all nature to his predetermined opinions. He is no lefs apt to suffer himself to be deluded by the obfervations favourable to his fyftem, fent to him by fubaltern candidates for the honour of being named in his writings. On fuch grounds he roundly afferts, that the whole chain of the Vofges is composed of granite, or of hard free-ftone. It may be fo on the fide of Lorrain; but I can answer for it that in Alface, in the part of the great chain from St. Odille to the Banc de la Roche, the whole of those mountains, from their feet to their fummits, are formed of a stone compofed of large and fmall pebbles cemented by a coarse fand. The Banc de la Roche is alone of granite; after which, in the principality of Salm, the same nature of rock begins again. In that branch which runs from Phalfburgh to Schirmeck, and to the Donau, including that mountain, the highest of all the Vofges, excepting a few quarries of purer and finer red, or reddish fand stone, and fome interfperfed of lime ftone, the fame remarkable kind of rock presents itself every where. From the like unfaithful reports, he affirms that the mines of St. Marie aux Mines have been worked to the depth of 200 toifes below the level of the Rhine: he fhould have faid, no doubt, 200 toifes below the entrance of their shafts on the high mountain of Giromani, far removed -from the Rhine. The levels or drains which have been made to draw off the waters from thofe mines are yet, as I was well informed in the country, far above the roots of that mountain. These mines are in great part abandoned, because the expence of making new drains, as yet very practicable, would exceed the probable profits. No fire engines have ever been employed; which, however, must have been neceffary, had the works been ever pushed a single inch below the level of the plain, or of the river many miles diftant diftant from the mountain. Many more inftances might be adduced of spurious or doubtful observations, boldly alleged as proofs of his fyftem. (c) Page 291. This affertion of Mr. de Buffon is not only not warranted, but feems contrary to the general fact. The famous mines of Potofi, in which, at their first discovery, fo much native filver, in great maffes, was found, are not fituated in the high mountains themselves, but in lower mountains, which may indeed be faid to belong to them; but are ifolated from the highest ridges of the Andes by intervening valleys. The mountain of Hartz, in Lower Saxony, and thofe in which filver mines are found in the duchy of Saxony, are not 400 toifes high. The mines of Hungary are not in the high ridges of mount Krapack. Though hilly, there are no high mountains in Cornwall, fo famous for its tin mines. The lead and copper mines of Derbyshire are in calcareous mountains, not 150 toifes in height; and this latter metal is found in many parts of England, in plain and level countries. Mr. de Buffon could not deny that no inconfiderable mines of gold and filver are worked in Siberia; but yet he affirms that gold and silver are almost the fole property of equatorial climates, for the single reason, that in these are found the highest mountains; yet it appears that in these fame fouthern regions native gold in great abundance is not only found in hilly or mountainous, but in plain and level countries. In 1771 the Spaniards, in an expedition against the Indians, found the richest mines of gold yet perhaps discovered, great quantities of which appeared even on the very furface of a plain of 14 leagues extent, at Cineguilla in the province of Sonora. So great was the harveft, that before the end of that fame year those hitherto defert and uninhabited plains had attracted 2000 workmen. Other rich mines of the fame metal were found in the province of Cinalao. VideRobertson's Notes to his Hiftory of America. The whole of thefe provinces, part of the kingdom of New Mexico, is, however, without mountains, and even diftant at least 200 leagues from any high mountain. The great veins of gold and filver ore are not always inchafed, as this author afferts, es afferts, in the perpendicular fiffures of mountains. Those of filver in the mines of Hartz are fo nearly horizontal as only to incline 10 or 12 degrees. The principal veins of lead or copper ore are, I apprehend, always either horizontal or very little inclined. They are fometimes fuddenly broken off by rocks, which have flipped down lower into fome deep cavern, and have carried down under them the hopes of the miner to unknown depths. To recover the loft vein, either shafts must be funk lower, if that part of the mountain with its various ftrata has funk down perpendicularly; or levels must be carried on either on one fide or on the other of this intervening wall of feparation, in cafe the bed of ore has only been shoved out of its direction by the lateral flip of the vein with its fuperincumbent ftrata in that particular part of the mountain. The fureft chance to recover the vein, is to feek for it at some distance, at the fame depth, and in the fame direction as it was found before the interruption. These are the occafions of great uncertainty in the profits of thefe mines. Owing to fimilar diflocations, great lumps or ifolated bodies of ore are fometimes found, which delude the miners with the hopes of finding a continued vein of equal richness. All these accidents prove the interior as well as exterior convulfion and diflocation, which almost all mountains have experienced since the creation of the earth, and for which the change of centre of gravity, and confequent fubverfion of great part of the earth, which I am perfuaded took place at the deluge, fufficiently account. (d) Page 305. This was contrary to the then established opinion, which was, that icy feas were fure indications of lands; and hence it was fuppofed, that a vait inacceffible continent lay under the antarctic pole. But from Captain Cook's obfervations it appears, that if northern fhores are frequently furrounded by ice, it is not on the account of the proximity of land, but on account of the fhallowness of the beach which environs it. Wherever the fhore is steep and the fea deep, there is no more folid ice than in open feas in the fame latitudes. The great depofits carried into the adjoining fea by thofe thofe mighty rivers the Oby, the Janifea and Irtifh, by rendering its coafts much shallower than formerly, are the probable caufes that the navigation, by coafting round to Kamchatzka, poffible according to fome accounts one hundred years ago, is now become impracticable by reason of ice perhaps now eternally fixed to the bottom of thefe fhallower coafts. There is probably no land under the antarctic pole, but the fea that furrounds it is fo fhallow, that in latitude 72 the ice is every where adherent to the bottom, and precludes all poffibility of further navigation. (e) Page 314. The whole difference, fays Mr. de Buffon, in the vitrification of vitreous and calcareous bodies is, that the first are capable of immediate vitrification, whereas the latter must first be calcined before they can be melted. Calcareous stones, fays he, may be finally reduced to glafs by the heat of burning glaffes. Mr. D'Arcet melted calcareous fpath without the addition of any other matter, in a fierce furnace, and by mixing vi treous matter with calcareous it may be melted in the more ordinary furnaces. Mr. de Buffon has appeared on many occafions fo very ready to admit the truth of every light experiment which has been offered to him when favourable to his fyftem, that we may reafonably require fuller proofs before we admit the certainty of these facts. Extraneous matters fo often imperceptibly alter the proceffes of chemistry, that we have a right to demand frequent and careful repetitions invariably offering the fame results. In the first case, what was melted was perhaps mixed with fome fubstance foreign to the calcareous matter; in the laft, where a distinct menftruum is added, the entire fufion may be very poffible. The different airs created by intense heats, the decompofition of falts or of particles of the veffel in which the experiment is made, may in both cafes have ferved as menftrua. (g) Page 322. The whole of the great chain of Mount Jura is calcareous. On its fummit, 3 D |