been mentioned. The colour of molybdena is described, p. 465, as fresh burning lead gray," probably meaning that it refembles newly melted lead. An equal, awkwardness is evident in the picture of red manganefe ore, where read, p. 463, colour light rofe red, by weathering becomes light yellowish brown.' It would fcarcely be proper to be fo critical in refpect to these minutiae of language if the common idiom of the country were ufed; but when that idiom is broken through, and the acknowledged intrufion attempted to be juftified by the pretence of fuperior accuracy, it be comes a matter of importance to determine how far this affertion is true.

The perfons who have adopted in English a bold literal tranflation of Werner's mode of defcribing foffils do not feem to difcriminate between the ufe of peculiar words as terms of art, and the abufe of expreffions in common use by giving them a new fignification. The adoption of terms of art from another language, or from the barbarous flang of the work fhop, does not caufe any confufion, but only enriches the language, at the fame time, however, that the trouble of youth and foreigners in learning, it is increased. On the other hand, the alteration of the fenfe of expreffions. in common ufe is not only a grofs offence against the purity of the language, but it renders the knowledge intended to be conveyed ridiculous to thofe accustomed only to the common meaning of the words, and who, of course, comprehend the far, nay very far greater number of readers. What in fact can be more ridiculous than a perfon affirming, that the diamond is " fnow white" inftead of colourlefs? that pumice is "fwimming" inftead of being fo light that it will fwim upon water? or when speaking of wacke, faying "it very characteristic of it that it falls in the open air?" Nor is it lefs abfurd to fpeak of the fracture of a foffil, when the grain or appearance of the broken part is meant to be defcribed.

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Since heliotrope, marle, loam, and fome other minerals are enumerated by Werner as oiyetognoftic fpecies, we cannot conceive why feveral kinds of rocks are denied a place in the Syftem, as it is allowed that the diffimilerity of their component parts cannot be perceived by the naked eye, and the ufe of a lens is prohibited in the Freyberg fchool. Among thefe omitted fpecies may be reckoned the bafis green porphyry, vol. ii. p. 131, already enumerated by Delametherie as two fpecies, under the names of ophitineand variolite, but which he fufpects to be in reality the fame

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foffil;

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foffil; the bafis of fienite porphyry, p. 140, which is the leucoftine of Delametherie; tranfition greenflone, p. 148; graywacke flate, p. 150; thofe kinds of fandftones which confift of quartz grains cemented by quartz, p. 155; fandftone flate, p. 157; falt clay, p. 174; peat, p. 208; nagel fluh, p. 210; moya, p. 354; and to these might perhaps be added fome kinds of graystone, p. 190.

We come at laít to the confideration of the third volume, which contains an explanation of Werner's Syftem of Geology, or, as he chufes to denominate it, Geognofy, This "he founds upon fucceffive depofitions from a watery folution, of which the fea is the remains. The chaotic fluid was of a very compound nature, and the firft depofitions from it are principally compofed of filica, alumina, and magnefia. The following metals, molybdena, menachan or titanium, tin, fcheele or tungften, cerium, tantalium, uran, chrome, and bifmuth are alfo inmates of thefe primitive depofitions. This chaotic fluid gradually diminished as thefe fediments were depofited, fo that the relative age of the fediments may, he fuppofes, be eftimated by the elevation of their outgoings on the prefent furface of the earth, the higheft being the oldest.

The feveral rocks are divided into five claffes, 1. The primitive, which were antecedent to the creation of organic beings, and were depofited while the earth was ftill covered with water; 2. The tranfition, or thofe contemporaneous with that creation, fo that the older inembers of this clafs contain fcarcely any remains of thofe beings, while in the newer rocks of this clafs they are numerous; 3. Floetz, or horizontally ftratified rocks, which not only contain petri. factions, but alfo bituminous fubftances, and thefe latter fubftances increase in quantity the newer the formation. 4. The alluvial, which comprehend the fubftances that are formed from previously exifting rocks, whofe materials have 'been worn down by water, and afterwards depofited in beds nearly horizontal on the furface of the land or at the bottom of the fea. 5. The volcanic, which arife from the fpontaneous combuftion of the bituminous depofitions of the third clafs of rocks.

As the combuftion of the bed of coal that fo often forms the bottom ftratum of the neweft floctz trap formation, and which is fometimes one hundred feet thick, is thought by Werner to be the caufe of volcanoes, it does not appear why volcanic rocks fhould be confidered not only as a formation, but even a feparate clafs of rocks, as they are

on this hypothefis only the floetz trap rocks in a state of decompofition. In p. 96 it is faid, that the volcanic ftatė appears foreign to the earth,-a circumflance that points out its great antiquity." This expreffion we do not underfland.

It is evident from the above flatement, that Mr. Jamefon, with the generality of thofe who have formed fyftems refpecting the formation of the globe, allows a confiderable period of time antecedent to the creation of organic beings. Nor is this the only particular in which he differs from the account given of the creation by the infpired pen of Mofes, as he propofes two separate rifings of the waters of the globe. The first, according to Werner, took place before the creation of vegetables or animals, while the folid part of the globe was ftill fubmerged beneath the fea; the depofition which took place in confequence of it, and which is called by the Freyberg fchool the fecond porphyry and fienite formation is, when complete, compofed, according to him, of four beds; the firft of confiderable magnitude, and formed from fragments of different primitive rocks; the fecond of clayftone, rather earthy in the lower part, but gradually be coming more compact, with included cryftals of felfpar, which increase in number, and at length cause the rock to poffefs the character of porphyry; this third bed of porphyry is covered with fienite, which forms the upper part of the depofition.

The fecond rifing of the water, to which the name of deluge may, as Mr. J. obferves, be more properly applied, as the dry land had appeared, and organic bodies been formed, is, according to Werner, the laft formation of the third clafs of rocks, and the peculiar beds which were then formed, that profeffor conceives to be bafalt wacke, green ftone, porphyry flate, and traptuff. An immenfe ftratum of coal, as has been already obferved, very often forms the lowermoft bed of this depofition, upon which reft several beds of coarfe fediments that had been merely fufpended by the violent motion of the water, as gravel, fand, bituminous wood, clay, and trap tuff. The coarfe chemical depofitions lie upon thefe, as bafalt, clay ftone, and wacke, and are covered by the fine chemical precipitates, as porphyry flate, grayftone, and greenstone. As thefe diluvial depofitions, to which Ma. J. gives the name of neweft floetz trap, are feldom fimilar to one another, but are compofed of rocks. agreeing only in the above circumftances of the coarfer depofitions lying lower than the finer, which is contrary to the

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ufual

ufual mode, it appears to us more probably that it is in fact a congeries of formations added together.

It is alfo to be obferved, that Mr. Jamefon follows Werner in claffing obfidian and pumice as members of this de pofition. His principal reafon is, that they contain water as one of their component ingredients, which is certainly plaufible enough; but the voice of ages has given a volcanic origin to fome varieties of thefe ftones. And how uncertain are the geological fpeculations of the Freyberg school is evidently fhown by the hesitation of Mr. Jamefon, whe ther the Caffle rock at Edinburgh (the place of his refidence) belongs to the neweft floetz trap formation. Indeed, we know that the difciples of Werner are fo obfervant of their mafter that they dare not form an opinion of their own, but wait implicitly for his determination on the minuteft points, and content themfelves with acquiring the faculty of recognizing at firft fight the minerals exhibited by him in his lectures.

In regard to the proper depofition of coals, called by Mr. J. the independent coal formation because it does not form a continuous depofition, but occurs in feveral feparate trough-fhaped hollows, and in bafins, fo that its frata are concave on their upper furface, we may remark, that this, circumftance feems to point its origin from the fediments of lakes.

Although the third volume is doubtlefs that to which the. principal attention of the author has been given, we ftill find in it the fame difregard to accuracy of expreffion as in his former productions. For after enumerating the twelve formations of floetz rocks, the three laft of which are thus quoted, p. 155,

10. Floetz trap formation,

1. Independent coal formation,

12. Newest floetz trap formation,"

he thus proceeds: "All thefe formations occur, in general, in a conformable pofition, but are covered with a great formation which we have already repeatedly mentioned, namely, the newest floetz trap." Here then we learn this curious fact, that the neweft floetz trap covers the newest floetz trap!

With an equal attention to propriety of expreffion we are informed, p. 216, that the loweft degree of activity "of a volcano is when it throws fmoke, and then it is faid to be in a ftate of reft." It is to be apprehended that the

neighbours

neighbours of these mountains are not perfectly pleafed with this ftate of reft, and would much rather have the volcano enjoy a rest undisturbed by the fymptoms of any activity whatever.

The heights of the mountains given in the beginning of the third volume, p. 17, are totally different from the lift at the end, p. 313 et feq. And in the like manner, the table of the ftructure of mountain rocks is in a different order from the text; neither do the feveral formations of floetz rocks fucceed in the fame order as that in which they are enumerated.

Although Mr. Jamefon promised in his firft volume, p. 123, to give a defcription of the fchorl rock of Cornwall, he has paffed it without any other notice than it is proba bly very intimately connected with topaz rock." He has alfo omitted to defcribe the conglomerate which is peculiar to the independent coal formation, and the foffil into which the flate clay in that formation fometimes paffes. Nor is it flated whether the white ftone is a diftinct or fubordinate formation, although this is a very important circumstance in the natural hiftory of a rock. It forms, we believe, fubordinate beds in the gneifs formation, and the garnet and cyanite that it contains may be regarded as effential conftituent parts, although Mr. Jamefon confiders them as only accidentally contained in it.

At the fame time that we thus condemn the execution of feveral parts of Profeffor Jamefon's Syftem, which is prefented to the public as a work that eclipfes all former writings upon mineralogy, and throws them completely into the fhade, we must candidly allow, that, if we except the horrid barbarisms which he has attempted, and we are afraid too fuccefsfully, to introduce into the English language, the faults in it are rather thofe of the fchool than of the individual. The fame inaccuracy of expreffion, the fame departure from the rules previously laid down, the fame uncertainty as to the real grounds upon which the fpecies are founded, which is indeed fo great that they appear to be formed only by fome inftinctive property in the obferver, and the truly ridiculous idea of the existence of paffages from one fpecies of fimple minerals to another, are to be found in the works of all the German mineralifts.

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