Article 3

ART. III. Outlines of Mineralogy. By J. Kidd, M. D. Professor of Chemistry in the University of Oxford. Oxford. Printed for Parker and Bliss, and Longman and Co. 2 vols. 8vo. pp. 518. 1809.

[pp. 61-74] [original article in PDF format]

  1. NATURAL History was scarcely cultivated by the ancients: for though some of them, Aristotle for example, and Pliny, collected a considerable number of facts, yet no regular attempt was made to arrange these facts, and to mould them into the form of a science. When learning revived, in the 15th and [61] 16th centuries, several men of eminence devoted themselves to Natural History. At first they confined themselves in a good measure to the restoration of the knowledge possessed by the ancients, and infinite labour was bestowed in endeavouring to ascertain the plants, animals and minerals alluded to, or described by Aristotle, Theophrastus, Dioscorides, Pliny and other Greek and Roman authors. The success was so disproportionate to the labour of this investigation, that at last it was in a great measure relinquished in despair, and philosophers directed their principal efforts to the description and classification of the different objects of natural history. Much industry and ability was exhausted upon this subject. Botany made the first progress, zoology the next. Each of these had its peculiar difficulties and its peculiar advantages.

  2. In both of these branches of natural history, the species in general were easily defined. Individuals of the same species resembled each other so exactly in external form, and differed so strikingly from those belonging to other species, that they were characterised, even at an early period, with considerable exactness. Linnaeus and his followers, to whom these branches of natural history lie under such deep obligations, found it necessary to make considerable changes, both in the genera and the descriptions, but the species in general were sufficiently well marked, and the preceding descriptions, though imperfect, were still tolerably precise, and served well enough to distinguish the species from each other.

  3. The case was very different in mineralogy. It is true that minerals, when in their most perfect form, especially when crystallized, differ so much from each other, that they may be also arranged into well characterised species. But in most cases minerals may be found that possess characters intermediate between these species, and approaching each by very slight shades of difference, so that it becomes difficult to say to which of two species they belong. The characters of minerals besides are much more variable than those of vegetables. Hence it is more difficult to describe them in an accurate and intelligible manner. The fact is, that animals and vegetables, except in a few instances, are divided by nature into well characterised species; but minerals graduate imperceptibly into each other. Hence more skill and knowledge are requisite in arranging them.

  4. We do not mean to deny that many minerals possess exact [62] and well-marked specific characters; and that there are different species of minerals, as well as of plants and animals. Every person who has dipped into the science, knows that such species exist. Thus for example, felspar, quartz, mica, hornblende, and many other minerals which will present themselves at once to the mind of the mineralogist, are well characterised species, and in no danger of being confounded with each other. What we mean is, that in examining an individual mineral, the characters of the species are not always to be perceived in perfection, so that it comes to be a question of some difficulty, for example, whether a particular mineral presented belongs to the species of hornblende or actinolite, and sometimes it is impossible to determine to which it belongs.

  5. The science of mineralogy therefore was attended with difficulties which neither occurred in zoology nor botany. The first difficulty was the consequence of the graduation of minerals into each other: it was to divide minerals into species. The second was the consequence of the variation of the characters: it was to describe minerals in an intelligible and precise manner. The early zoologists and botanists were frequently diffuse and awkward in their descriptions, but it will be acknowledged that they describe with considerable precision, and in most cases it is possible to recognize the species which they mean to characterise. But the early mineralogists were unable to describe at all. They satisfied themselves with a bare catalogue of the different minerals with which they were acquainted; if we except a few crystals, the forms of which they noted, and a few colours which they occasionally mention. Even Linnaeus, who succeeded so well in the other two branches of natural history, was not fortunate in his attempt to describe minerals. Indeed if we except the account he gives of the shape of some crystallized minerals, we may say in general, without being too severe in our censure, that he either gives no description at all, or that what he does describe is scarcely intelligible. His attempts at classification were, if possible, still more preposterous. What, for example, could be more absurd than to place together nitre and quartz? We do not mean to deny that Linnaeus attempted to invent a mineralogical language; but he either does not adhere to his own definitions, or they are too short to be of much utility. His merit as a mineralogist consisted chiefly in bringing into view crystallization, and in pointing it out as one of the most important characters of minerals. [63]

  6. To Werner, the celebrated professor of Freyberg, we are much indebted for the first accurate language of mineralogy. He published the first account of it in 1774, since that time he has added many considerable and important improvements. He first pointed out the characters from which the minerals ought to be described, defined them with accuracy, and marked the limits of each. Before the appearance of this important work, minerals had not been described at all, but merely named: all who have since attempted to describe them, have borrowed freely from this illustrious mineralogist.

  7. One branch of description indeed has been brought to perfection in a different quarter, we mean crystallography. Romé de Lisle, who had devoted much attention to the figures of crystals, published a work on crystallography in 1783, in which all the different crystals which had been observed were described, figured, and classified in a much more complete and scientific manner than had been previously attempted. He reduced the crystalline shape of each species to a particular form, and shewed how all the other forms were derived by certain truncations of the edges or angles of the primitive crystal. This work was of great importance, not only on account of the vast number of accurate descriptions which it contained, but of the new views which it communicated. Since that time the Abbé Hauy has new-modelled, and greatly improved the whole doctrine of crystallography, reduced it to fixed mathematical principles, and founded on it a system of mineralogy which has gained numerous disciples, and indeed is in many respects entitled to much commendation.

  8. These two philosophers, Werner and Hauy, have thus laid the foundation of two distinct mineralogical schools, possessed each of their peculiar advantages, and distinguished each by their disciples and admirers. Werner excels in description, Hauy in his account of crystalline forms. Werner has excelled in his rules for determining species, and in his application of these rules; Hauy has laid down a single character, which appears at first sight sufficient and easily determined. Both of them have added considerably to the number of known minerals, and both have formed many new species which have been admitted by all mineralogists as proper and correct. The method of Hauy, however, labours under an imperfection, which, if it adds considerably to its elegance and simplicity, greatly diminishes its application and utility. It applies only to crystallized minerals. [64] All those minerals which have no crystallized form cannot be determined by it. Now as these minerals are numerous and important, it is obvious that Hauy's method cannot be considered as a system of mineralogy, but as embracing only a part of that system. To know the whole, we must have recourse to the method of Werner, whose descriptions apply equally to all minerals. His account of crystals is neither so scientific, nor so mathematically accurate as that of Hauy; but it is sufficiently precise to characterize all crystallized minerals by their form.

  9. Werner's method is of more difficult acquisition than Hauy's. It requires a longer study, and a careful comparison of the characters of minerals by specimens: but it is absolutely necessary to possess it, not only to be able to describe minerals with precision, but even to know them with accuracy. All other mineralogical writers have borrowed this method to a certain extent, even Hauy has availed himself of it in every description: but it may be said with truth, that no one has hitherto used it correctly except Werner and his disciples. The reason seems to be, that none else have bestowed the time and attention requisite to acquire a perfect knowledge of the characters.

  10. We thought the preceding introduction necessary before we entered upon the consideration of Dr. Kidd's work on mineralogy, in order to put the reader in the way of judging with more ease and accuracy of its merits and defects.

  11. Mineralogy has not till lately been a favourite study in this country. It is true, indeed, that we have had mineralogical writers of considerable celebrity, taking into account the period when they wrote. Thus Woodward was in all probability just as well acquainted with minerals as any in his time; and the same observation we should think applies to Sir John Hill. His attempts at arrangement indeed were unfortunate; and the tone of writing in which he chose to indulge, cannot be much approved of. Neither does he appear to have been acquainted with the chemical discoveries of his time: for in his treatise on Spars, published at least ten years after the great discovery of Dr. Black, he does not seem to know what constitutes the difference between quicklime and limestone. In latter times Dr. Withering appears to have paid considerable attention to minerals. He made us acquainted with Bergman's valuable chemical arrangement, by publishing it in an English dress: to him also we are indebted for the discovery of a new species, which in consequence bears his name. But Kirwan is by far the most eminent of our mineralogists [65] who has not imbibed his information by studying under some foreign master. His system of mineralogy indeed, the second edition at least, to which alone we allude, professes to adopt the Wernerian method; and no doubt much information was obtained from the German writers on the subject, as well as from the Leskean cabinet, which he had an opportunity of examining and studying: but as Mr. Kirwan did not himself study under Werner; and as no immediate pupil of Werner had published when he wrote, he must be considered in some respects as a British mineralogist. The object of Professor Jameson was to give a correct view of the system of Werner; an object which he has accomplished with much fidelity. His system is by far the most important which we have in our language; and indeed the only one by which the student can hope to investigate species.

  12. Dr. Kidd professes to copy the method of Hauy. But the essential part of Hauy's system has been omitted by him; we mean the accurate description of the crystallized forms of minerals: we cannot therefore consider his work as moulded upon Hauy's plan. All that Dr. Kidd can mean is, that he has borrowed from Hauy many names of species, and such descriptions as he has given. Let us now examine his work with some attention.

  13. He has adopted the common division of minerals into four classes; namely, earthy substances, salts, inflammable bodies, and metals. This is the classification of all modern mineralogists, and appears to us sufficiently proper.

  14. The earthy substances he divides into eight genera. In this particular he follows the plan laid down by Cronstedt and Bergman, and adopted by Werner. He professes to adopt the peculiar arrangement of Kirwan, except where subsequent discoveries have rendered it necessary to deviate from that arrangement. The names of the genera are, lime, strontian, baryt, magnesia, zircone, glucine, alumine, silex. These are the names of the different earths at present known, (yttria excepted, the minerals containing which Dr. Kidd omits); and the stony bodies placed under each genus are those which contain a greater proportion of the respective earth than of any other, or which, at least, are supposed to derive their peculiar qualities from that earth. This division was originally introduced into mineralogy by Cronstedt, and has been followed ever since by almost all mineralogical writers. It would be unfair to blame Dr. Kidd for adopting it. Yet it will be allowed [66] we presume, upon examination, to be a very defective, and, in not a few cases, a very absurd arrangement: the three first genera indeed answer pretty well; for most minerals contained in them consist chiefly, or entirely, of the earth which stands at the head of the genus, and to that earth of course they owe most of their properties. The case is very different with the other genera; the minerals arranged under them contain usually two or more earths, and in many cases it is impossible to say which of these earths gives the mineral its peculiar characters. The beryl, for example, is arranged under the genus glucine, though it does not contain above one seventh of its weight of the earth called glucina: as silica is the preponderating earth, the beryl, according to the system, ought to be arranged in the siliceous genus. The same observation applies to the emerald and the euclose, the only other minerals arranged under the glucine genus. In fact, no mineral known contains a preponderancy of glucina; so that the glucine genus, according to the system, ought not to exist at all. Again, chlorite is arranged under the magnesian genus, though it contains at most only one 12th of its weight of magnesia: indeed the proportion of oxide of iron in this mineral is usually double that of the magnesia, and that of silica at least triple. Similar observations might be applied to actinolite, asbestus, and indeed to almost all the minerals arranged by Dr. Kidd under the magnesian genus. In like manner mica, fuller's earth, felspar, and many other minerals arranged under the aluminous genus, contain a preponderancy of silica. The siliceous genus is in general better, most of the minerals placed under it containing an excess of silica: yet it cannot be said with propriety that they derive their peculiar characters from that earth.

  15. We have the following objections to these genera. 1. They are entirely chemical, and lay mineralogy too much under the trammels of chemistry: were they to be adopted rigidly, no mineral could be arranged in the system till it had been analysed, and an erroneous analysis would give it a wrong place in the system. Such erroneous analyses are very common, owing to the ignorance of many chemists of the real characters of minerals; thus Chenevix published an analysis of Mica, under the name of Talc: the place of minerals in the system ought to depend upon their external characters. 2. Minerals cannot always be arranged under these genera, even when their composition is known; because very often they contain nearly the same proportion of two or three earths, and their peculiar characters [67] cannot be ascribed to one, but to the joint effect of all. 3. Even if minerals could be arranged under them, still these genera are useless, because they have no peculiar character, and do not therefore facilitate the knowledge of minerals. When a mineral is presented to us, whatever may be the characters which it exhibits, it is impossible to say under what genus it is arranged in the system, without great risk of mistake.

  16. Hauy, in consequence of these or similar reasons, has discarded these genera altogether. In this we think he has acted right; though we do not so much approve of his conduct in abolishing genera altogether, and describing all the species in succession without any subdivision. Werner's arrangement of minerals into families, we consider as by far the most valuable which has yet been made. Those minerals whose characters approach, are grouped together, and considered as belonging to one family: this is a material arrangement, which considerably facilitates the investigation of mineral species. Were these families adopted, and the old genera discarded, we should consider it as the best division of stony bodies at present possible. This has been done by one English writer and by one only. To these families which constitute one of the peculiar advantages of the Wernerian system, Dr. Kidd has paid no attention whatever: thus the leucite and garnet, which both belong to the garnet family, and which have always been allowed to bear a considerable resemblance to each other, instead of being near each other in Dr. Kidd's work, are placed under different genera, and at a great distance. Many similar examples might be selected if it were necessary: indeed it would be difficult to assign any reason for the order in which the species occur. He deviates very far from Kirwan, and from all other writers: the order we should conceive to have been the result of accident, not of design.

  17. We have perused the whole of Dr. Kidd's work with a great deal of pleasure. It is by far the most entertaining book on the subject which we have had an opportunity of examining. The style is excellent: unaffected, distinct, and perspicuous; it is admirably fitted for a work of science. But here our commendations must terminate. The defects are striking, and cannot escape any person who is moderately acquainted with the subject. But as the study is only a new one in Britain, we think it necessary to enter somewhat into particulars, in order to prevent those who are entering upon mineralogy from being misled by these mistakes, or from forming a wrong notion of the nature of the science. [68]

  18. 1. The first defect is the total want of accurate descriptions. For example, serpentine, the first species of Dr. Kidd's magnesias genus, is thus described;

    'Infusible in the heat of the Berlin porcelain furnace. In hardness superior to carbonate of lime: but it may in general be scratched by a knife. Specific gravity varies from 2.26 to 3.'

    Now this is a description which (besides being incorrect) we venture to affirm would never enable a learner to discover whether any mineral he was examining was serpentine or not. Indeed it would apply equally well to many other minerals, besides serpentine. The same observation may be made of all the descriptions in the book: they do not discriminate the minerals from each other, and of course are nearly useless to the student; for whose service alone such a treatise as this can be supposed to be written. In this respect Dr. Kidd is inferior to Hauy. The French mineralogist does not indeed excel as a describer; but he contrives in general to characterise his minerals in such a way that they may be ascertained. He is also below Kirwan, who has indeed frequently fallen into mistakes in his descriptions, owing to the imperfect state of the science at the time, and to his not always understanding clearly the descriptive language of Werner: still, however, his descriptions are often very exact, as well as sufficiently minute. It is rather singular that Dr. Kidd should, in this most essential point, have come short of those whom he professes to copy; and can only be accounted for by his not being aware of the necessity of description. Indeed he does not appear to have much studied the characters of minerals, or to be very intimately acquainted with the language of description; hence the properties which he assigns are not always correct. Thus he says, (Vol. I. p. 95) that noble serpentine has sometimes a broad and flat foliated structure; though it be well known to mineralogists that serpentine never has that structure. To give another example, he says, (Vol. I. p. 2l7) that the fracture of chalcedony has a waxy appearance with a slight degree of transparency. Now this is quite inconsistent with the meaning attached to the word fracture by all mineralogists. It was incumbent on Dr. Kidd, either to use the term in its general acceptation, or to have given an explanation of the meaning which he affixed to it. Even according to the common English meaning of the word fracture, the description conveys nothing, and is of course reprehensible. [69]

  19. 2. Another defect in Dr. Kidd's work struck us not a little, as it relates to one of the most important points in mineralogy; a point upon which much attention has been bestowed by almost all preceding writers, and in which Hauy, Dr. Kidd's great model, has laboured with very considerable success. We allude to the distribution of minerals into species, which is of so much importance for their accurate discrimination and arrangement. From the beginning to the end of the work, this distribution has been entirely overlooked; so that it is impossible to know what minerals Dr. Kidd considers as species, and what as varieties. Thus he describes about 20 different kinds of marble in the same manner, and with the same distinctions as he does different species. Does he consider them as distinct species? If so, his notion of species is inaccurate; if not, his mode of arranging them is wrong. In like manner he describes seven varieties of fluate of lime as distinct species; though they altogether constitute but one species, and can at most be considered as varieties. In his account of felspar (Vol. I. p. 157) we have, first felspar, by which we presume is meant common felspar; then we have adularia, then argentine felspar, and green felspar, both of which are only varieties of common felspar; lastly we have compact felspar, said to be crystallized in granite, a situation in which it never occurs: all these varieties are considered as distinct species.

  20. It is needless to produce any more examples, though they might be brought in abundance from almost every part of the work. We shall satisfy ourselves, therefore, with referring to sulphate of barytes, to Jasper, (Vol. I. p. 206) to opal, (Vol. I. p. 227) to talc, (Vol. I. p. 106) and above all to chalcedony, (Vol. I. p. 217 to 227) where onyx, stratified onyx, cacholong, mocoa stone, all only varieties of chalcedony, figure as distinct. Cacholong is even said to be an agate; now cacholong is a simple stone, whereas agate is a compound. We every where find varieties exalted into species, and varieties and species jumbled together in the most inextricable confusion; this is the more remarkable, as it would have been so easy to avoid it.

  21. 3. A third defect, which is in some measure the consequence of the preceding, is, that many different species are confounded together, and described as the same. This defect injures the progress of the science much more than that of arranging varieties as distinct species, and could only have been fallen into by a writer imperfectly acquainted with the present state of mineralogy. For example, garnet, melanite, and pyrope, are [70] but one species according to Dr. Kidd, which he distinguishes by the name of garnet: this appears from the list of analyses which he quotes. Thus, also, touchstone (Vol. I. p. 215) is said to be a variety of primitive shistus. We should like much to hear the characters stated which shew that touchstone and primitive shistus (common slate) are varieties of each other: the two minerals have very little resemblance. The account of novaculite shews that our author has no adequate conception of the nature of the species. He calls it a remarkable compact siliceous shistus; terms not at all applicable to the true novaculite, or whetstone of Werner. Again, we have semiopal, pitch-stone, and woodopal, confounded together, (Vol. I. p. 231) though nothing can be more distinct: pitchstone, for example, is easily found, semiopal not. In the same page we are told that menilite is a variety of semiopal. The reader may consult the account given of beryl, lithomarge, ochres, for examples of similar mistakes.

  22. 4. The next defect which we have to point out, is, that a great many species are left out altogether. In the first class alone we counted at least fifty, which ought to have found a place, but are omitted: many of these are not recently discovered minerals, but minerals which have been long known, and which occur pretty frequently in this country: as for example, anclaluzite, chiastolite, zoizite. The account of the inflammable bodies is also defective. Here both Kirwan and Hauy, from whom our author copied, were very poor; but we have an excellent description of them in Professor Jameson's mineralogy, a work which Dr. Kidd appears to have seen, as he sometimes quotes it, but which he does not seem to have properly appreciated. We have not examined the class of metallic bodies so narrowly as to enumerate the species overlooked; though here, also, many remarkable omissions struck us; as for example, electrum, a new species of gold ore, sometime ago pointed out by Klaproth. We believe that not fewer than 50 species of well ascertained metallic substances have been omitted by our author.

  23. 5. A good many references are made in the volumes under our consideration to the writings of the ancients, especially to Pliny and Theophrastus, in order to explain the names of minerals which occur in them: we notice this with pleasure, as it forms a distinguishing feature of the work. In most of these Dr. Kidd is very successful; in one or two instances, however, we think that he has been misled: for example, he tells us [71] that the serpentine of the moderns is different from that of the ancients. Ancient serpentine he says, is green porphyry (Vol. I. p. 93): now, from specimens which remain, it is known that the antique serpentine is a very beautiful variety of the serpentine of the moderns. The term green porphyry is applied by the moderns to the same mineral that it was by the ancients. We can assure Dr. Kidd that the mineral cut into ornaments at Zöblitz, in Upper Saxony, is not potstone, as he supposes, (Vol. I. p. 95) but common serpentine. Dr. Kidd does not appear to be acquainted with true potstone. The Duke of Argyl's house, at Inverary, is not built of potstone, as he imagines, but of chlorite slate, which abounds in the neighbourhood of Lochfine.

  24. 6. It is very remarkable, that through the whole of this work not the least regard has been paid to the numerous natural relations of the species, even when it could have been done with the greatest propriety, and when it ought to have been done for the sake of perspicuity. The geognostic characters and relations are occasionally mentioned, but in such a manner as to shew that the author has no very precise ideas on Geognosy. One example or two is all which we have room to adduce. He says that the cavities of basaltic rocks are often lined with earthy chlorite, (Vol. I. p. 115). Now chlorite never occurs in basaltic rocks: the mineral which he considers as chlorite, is green earth. To confound these two minerals together, besides uniting substances that are very different, would be highly injurious to geognosy. Our author follows Dolomieu in considering the green earth of Verona as chlorite. We can assure him, notwithstanding the authority on which he relies, that the mineral in question is common green earth. In page 218 of Vol. I. he speaks of pseudo-crystals of chalcedony as frequent: the crystals alluded to are not pseudo-morphous, as he supposes, but true crystals, of which they possess all the characters. They belong, however, not to chalcedony, but to a variety of quartz, called by the Germans milk-quartz.

  25. We do not altogether approve of the work in a chemical point of view. The best and most accurate analyses of the different species are not always given: this is the more to be regretted, on the present occasion, as the author might have found them ready collected to his hand, together with the proper references, in the third edition of Thomson's Chemistry, vol. 4th; a work which Dr. Kidd does not appear to have consulted. We are very unwilling to suspect him of making his references to other [72] authors at second-hand, because this is a dangerous practice, and utterly unworthy of his acknowledged abilities; but we have occasionally found a discrepancy on turning to the originals.

  26. One topic still remains to be noticed; a topic of great importance, as the discovery of useful minerals, and the success of mining in some measure depend upon it. Minerals seldom occur simple; they are usually aggregated together under the name of rocks: indeed the whole of this globe, as far as we know, is composed of rocks. The nature, position, and formation of rocks, have formed a branch of investigation distinguished in this country by the name of geology; but which Werner and his pupils have called geognosy. Our author treats of rocks in an Appendix of 39 pages, which is by far the most imperfect part of the whole work: nothing whatever is said about their relative situation; even the names and composition of most of them seem to be unknown. The different species of rocks amount to about 45. Dr. Kidd has only mentioned about 12. This is the more remarkable, as two pretty detailed and accurate description of the different rocks, their situation and composition, had already appeared in an English dress: the first in the 4th Vol. of the 3d edition of Thomson's Chemistry, where it occupies about 45 pages; the second in the 3d Vol. of Professor Jameson's Mineralogy, consisting of 368 pages, and written expressly upon rocks. Had Dr. Kidd looked into either of these books he would have acquired much important information on the subject. Dr. Thomson confines himself to the description and situation of the rocks; Professor Jameson mixes the Neptunian theory of their formation: but his details are accurate, and his descriptions the fullest and most precise which have yet appeared.

  27. We have not room to enter into particulars. To Werner we are indebted for almost all that we know respecting rocks and their situation: Geognosy scarcely existed till he moulded it into the form of a science. Saussure, indeed, and Deluc, and some others, had devoted a good deal of attention to the subject; but their previous imperfect acquaintance with minerals occasioned a great number of mistakes, as Saussure himself has acknowledged. Almost every page of the appendix demonstrates that our author is below Saussure and Deluc, in his knowledge of rocks, and not much above Hauy, whose ignorance of geognostic subjects must have been felt by himself. Granite, he says, is sometimes so similar to whin, that they cannot [73] be distinguished. We have seen granite that might be mistaken for sandstone; but never any that had a resemblance to whin; that is, to greenstone. Clay slate he considers as a variety of micaceous shistus; though the one be a compound of mica and quartz, and the other a simple mineral. He makes the Giant's Causeway, the pillars of Staffa, and the castle rock of Edinburgh to be basalt: though none of them are composed of that mineral. Trap, according to him, is a variety of basalt: had he reversed the position, it would have been nearer the truth. Trap is the name given to a number of rocks distinguished by the great quantity of hornblende which they contain. Basalt is connected with some of these rocks, and therefore may, in a loose acceptation of the word, be called a variety of trap: but the trap rocks are mostly compounds, and basalt is a simple mineral. There is a set of rocks distinguished in Werner by the name of Floetz trap, and basalt is one of these rocks. Clinkstone our author confounds with basalt, and does not discriminate between clinkstone and porphyry slate, though the one be a simple mineral, and the other a compound. Amygdaloid he considers as synonimous with the roche de corne of French writers: but the last we consider as compact felspar, a very different mineral from amygdaloid.

  28. It is with reluctance, and from an anxious wish to promote the good of the science that we have been thus particular in pointing out the defects of the present work. We are far from entertaining a humble opinion of Dr. Kidd's talents, which, even from the specimen here presented, appear indeed very respectable. But we perceive that he has not attended minutely to the study of mineralogy, and suspect that he has drawn his information chiefly from the Mineralogical Lectures of the Chemical Professors in this country, who are in general too imperfectly acquainted with the subject to convey much useful information. [74]