Art. II. Review of an elementary Treatise on Mineralogy and Geology.
Art. II. Review of an elementary Treatise on Mineralogy and Geology, being an introduction to the study of these sciences, and designed for the use of pupils; for persons attending lectures on these subjects; and as a companion for travellers in the United States of America—Illustrated by six plates. By Parker Cleaveland, Professor of Mathematics and Natural Philosophy, and Lecturer on Chemistry and Mineralogy in Bowdoin College, Member of the American Academy, and Corresponding Member of the Linnæan Society of New England.
—— itum est in viscera terræ:
Quasque recondiderat, Stygiisque admoverat umbris,
Effodiuntur opes —— Ovid.
Boston, published by Cummings and Hilliard, No. 1, Cornhill. Printed by Hilliard & Metcalf, at the University Press, Cambridge, New England. 1816.
This work has been for some time before the public, and it has been more or less the subject of remark in our various journals. It is, however, so appropriate to the leading objects of this Journal, that we cannot consider ourselves as performing labours of supererogation while we consider the necessity, plan, and execution of the treatise of Professor Cleaveland.
An extensive cultivation of the physical sciences is peculiar to an advanced state of society, and evinces, in the country where they flourish, a highly improved state of the arts, and a great degree of intelligence in the community. To this state of things we are now fast approximating. The ardent curiosity regarding these subjects, already enkindled in the public mind, the very respectable attainments in science which we have already made, and our rapidly augmenting means of information in books, instruments, collections, and teachers, afford ground for the happiest anticipations.
Those sciences which require no means for their investigation beyond books, teachers, and study—those which demand no physical demonstrations, no instruments of research, no material specimens: we mean those sciences which relate only to the intellectual and moral character of man, were early fostered, and, in a good degree, matured in this country. Hence, in theology, in ethics, in jurisprudence, and in civil policy, our advances were much earlier, and more worthy of respect, than in the sciences relating to material things. In some of these, it is true, we have made very considerable advances, especially in natural philosophy and the mathematics, and their applications to the arts; and this has been true, in some good degree, for very nearly a century. Natural history has been the most tardy in its growth, and no branch of it was, till within a few years, involved in such darkness as mineralogy. Notwithstanding the laudable efforts of a few gentlemen to excite some taste for these subjects, so little had been effected in forming collections, in kindling curiosity, and diffusing information, that only fifteen years since, it was a matter of extreme difficulty to obtain, among ourselves, even the names of the most common stones and minerals; and one might inquire earnestly, and long, before he could find any one to identify even quartz, feldspar, or hornblende, among the simple minerals; or granite, porphyry, or trap, among the rocks. We speak from experience, and well remember with what impatient, but almost despairing curiosity, we eyed the bleak, naked ridges, which impended over the valleys and plains that were the scenes of our youthful excursions. In vain did we doubt whether the glittering spangles of mica, and the still more alluring brilliancy of pyrites, gave assurance of the existence of the precious metals in those substances; or whether the cutting of glass by the garnet, and by quartz, proved that these minerals were the diamond; but if they were not precious metals, and if they were not diamonds, we in vain inquired of our companions, and even of our teachers, what they were.
We do not forget that Dr. Adam Seybert, in Philadelphia; Dr. Samuel L. Mitchill, in New-York; and Dr. Benjamin Waterhouse, in Harvard University, began at an earlier period to enlighten the public on this subject; they began to form collections; Harvard received a select cabinet from France and England; and Mr. Smith, of Philadelphia, (although, returning from Europe fraught with scientific acquisitions, he perished tragically near his native shores,) left his collection to enrich the Museum of the American Philosophical Society.
Still, however, although individuals were enlightened, no serious impression was produced on the public mind; a few lights were indeed held out, but they were lights twinkling in an almost impervious gloom.
The return of the late Benjamin D. Perkins, and of the late Dr. A. Bruce, from Europe, in 1802 and 3, with their collections, then the most complete and beautiful that this country had ever seen; the return of Colonel Gibbs, in 1805, with his extensive and magnificent cabinet; his consequent excursions and researches into our mineralogy; the commencement, about this time, of courses of lectures on mineralogy, in several of our colleges, and of collections by them and by many individuals; the return of Mr. Maclure, in 1807; his Herculean labour in surveying the United States geologically, by personal examination; and the institution of the American Journal of Mineralogy, by Dr. Bruce, in 1810;—these are among the most prominent events, which, in the course of a few years, have totally changed the face of this science in the United States.
During the last ten years, it has been cultivated with great ardour, and with great success: many interesting discoveries in American mineralogy have been made; and this science, with its sister science, Geology, is fast arresting the public attention. In such a state of things, books relating to mineralogy would of course be eagerly sought for.
No work, anterior to Kirwan, could be consulted by the student with much advantage, on account of the wonderful progress, which, within forty or fifty years, has been made in mineralogy. Even Kirwan, who performed a most important service to the science, was become, in some considerable degree, imperfect and obsolete; the German treatises, the fruitful fountains from which the science had flowed over Europe, were not translated; neither were those of the French; and this was the more to be regretted, because they had mellowed down the harshness and enriched the sterility of the German method of description, besides adding many interesting discoveries of their own. It is true we possessed the truly valuable treatise of Professor Jameson, the most complete in our language. But the expense of the work made it unattainable by most of our students, and the undeviating strictness with which the highly respectable author has adhered to the German mode of description, gave it an aspect somewhat repulsive to the minds of novices, who consulted no other book. We are, however, well aware of the value of this work, especially in the improved edition. It must, without doubt, be in the hands of every one who would be master of the science; but it is much better adapted to the purposes of proficients than of beginners.
The mineralogical articles dispersed through Aikin's Dictionary are exceedingly valuable; but, from the high price of the work, they are inaccessible to most persons.
The most recent of the French systems, that by Brongniart, seemed to combine nearly all the requisites that could be desired in an elementary treatise; and a translation of it would probably, ere this, have been given to the American public, had we not been led to expect the work of Professor Cleaveland, which, it was anticipated, would at least possess one important advantage over the work of Brongniart, and every other; it would exhibit, more or less extensively, American localities, and give the leading features of our natural mineral associations.
Thus it appears[8] that the work of Professor Cleaveland was eminently needed; the science, at large, needed it; and to American mineralogists it was nearly indispensable. It appeared too at a very opportune moment. Had it come a few years sooner, it might not have found many readers. Now it is sustained by the prevailing curiosity, and diffused state of information regarding mineralogy; and, in turn, no cause could operate more effectually to cherish this curiosity, and to diffuse this information still more widely, than this book. Professor Cleaveland is therefore entitled to our thanks for undertaking this task; and, in this age of book-making, it is no small negative praise if an author be acquitted of unnecessarily adding to the already onerous mass of books.
With respect to the PLAN of this work, Professor Cleaveland has, with good judgment, availed himself of the excellencies of both the German and French schools.
Mr. Werner, of Fribourg, in some sense not only the founder of the modern German school of mineralogy, but almost of the science itself, is entitled to our lasting gratitude for his system of external characters, first published in 1774. In this admirable treatise he has combined precision and copiousness, so that exact ideas are attached to every part of the descriptive language, and every character is meant to be defined.
It is intended that a full description of a mineral upon this plan shall entirely exhaust the subject, and that although many properties may be found in common among different minerals, still every picture shall contain peculiar features, not to be found in any other. It would certainly appear, at first view, that this method must be perfect, and leave nothing farther to be desired. It has, however, been found in practice, that the full descriptions of the Wernerian writers are heavy and dry; they are redundant also, from the frequent repetition of similar properties; and from not giving due prominence to those which are peculiar, and therefore distinctive, they frequently fail to leave a distinct impression of any thing on the mind, and thus, in the midst of what is called by the writers of this school a full oryctognostic picture, a student is sometimes absolutely bewildered.
Some of the modern French writers, availing themselves of Mr. Werner's very able delineation of the external characters of minerals, have selected such as are most important, most striking, distinctive, and interesting; and drawing a spirited and bold sketch, have left the minuter parts untouched: such a picture, although less perfect, often presents a stronger likeness, and more effectually arrests the attention.
This is the method of description which has been, as we think, happily adopted, to a great extent by Mr. Cleaveland.
Mr. Werner, availing himself of the similarities in the external appearance of minerals, has (excepting the metals) arranged them also upon this plan, without regard to their constitution; that is, to their real nature, or, at least, making this wholly subservient to the other: this has caused him, in some instances, to bring together things which are totally unlike in their nature, and, in other instances, to separate those which were entirely similar. Whatever may be said in favour of such a course, considered as a provisional one, while chemical analysis was in its infancy, the mind can never rest satisfied with any arrangement which contradicts the real nature of things; in a word, the composition of minerals is the only correct foundation for their classification. This classification has been adopted by several of the ablest modern French writers.
"It is believed," (says Professor Cleaveland, Preface, p. 7.) "that the more valuable parts of the two systems may be incorporated, or, in other words, that the peculiar descriptive language of the one may, in a certain degree, be united to the accurate and scientific arrangement of the other.
"This union of descriptive language and scientific arrangement has been effected with good success, by Brongniart, in his System of Mineralogy—an elementary work, which seems better adapted both to interest and instruct, than any which has hitherto appeared. The author of this volume has, therefore, adopted the general plan of Brongniart, the more important parts of whose work are, of course, incorporated with this."
A happier model could not, in our opinion, be chosen; and we conceive that Professor Cleaveland is perfectly consistent, and perfectly perspicuous, when, adopting the chemical composition of minerals as the only proper foundation of arrangement, and, of course, rejecting the principle of Mr. Werner, which arranges them upon their external properties, he still adopts his descriptive language as far as it answers his purpose. For to elect a principle of arrangement, and to classify all the members of a system so as to give each its appropriate place, is obviously quite a different thing from describing each member, after its place in a system is ascertained. In doing the latter, characters may be drawn from any source which affords them.
In his "Introduction to the Study of Mineralogy," the author has given a view at once copious, condensed, and perspicuous, of all that is necessary to be learned previously to the study of particular minerals. He begins with definitions and general principles, which are laid down with clearness.
By way of engaging the attention to the study of this department of nature, he remarks:
"From a superficial view of minerals in their natural depositories, at or near the surface of the earth, it would hardly be expected that they could constitute the object of a distinct branch of science. Nothing appears farther removed from the influence of established principles and regular arrangement, than the mineral kingdom when observed in a cursory manner. But a closer inspection and more comprehensive view of the subject will convince us, that this portion of the works of nature is by no means destitute of the impress of the Deity. Indications of the same wisdom, power, and benevolence, which appear in the animal and vegetable kingdoms, are also clearly discernible in the mineral."
"It may also be remarked," continues the author, "that several arts and manufactures depend on mineralogy for their existence; and that improvements and discoveries in the latter cannot fail of extending their beneficial effects to the aforementioned employments. In fine, the study of mineralogy, whether it be viewed as tending to increase individual wealth, to improve and multiply arts and manufactures, and thus promote the public good; or as affording a pleasant subject for scientific research, recommends itself to the attention of the citizen and scholar."
This introductory view of the importance and interest of the science cannot be charged with the fault of exaggeration, since it is most evident that neither civilization, refinement in arts, nor comfort, can exist where the properties of mineral substances are but imperfectly understood.
As regards this country, the argument admits of much amplification. The more our mineral treasures are explored, the more abundantly do they repay the research; and we trust that the period is not far distant, when we shall no longer ignorantly tread under our feet minerals of great curiosity and value, and import from other countries, at a great expense, what we, in many instances, possess abundantly at home.[9]
But to return to the plan of the author's work. Few persons, unacquainted with the science of mineralogy, would suspect that mere brute matter could exhibit many strong marks, capable of discrimination.
It may, however, be confidently affirmed, that there is no mineral which, if carefully studied, may not be distinguished by characters sufficiently decisive from every other mineral; an account of these characters ought, therefore, to precede every system of mineralogy. Professor Cleaveland has, with entire propriety, included them under the heads of crystallography, physical and external characters, and chemical characters.
He has given a clear view of the Abbé Haüy's curious discoveries regarding the six primitive figures or solids which form the bases of all crystals—the three integrant particles or molecules which constitute the primitive forms, and of the theory by which it is shown how the immensely numerous and diversified secondary or actual forms arise out of these few elementary figures.
This is certainly one of the most singular and acute discoveries of our age. It is true, there is a difference of opinion among mineralogists as to the practical use of crystallography in the discrimination of minerals. Some dwell upon it with excessive minuteness, and others seem restless and impatient of its details. The truth seems to be, that those who understand it, derive from it (wherever it is applicable) the most satisfactory aid; and it requires only a moderate knowledge of geometry to understand its principal outlines. On the other hand, it is no doubt possible, in most instances, to dispense with its aid, and to discriminate minerals by their other properties.
Of the external and physical characters of Mr. Werner, Mr. Cleaveland has given a clear account, combining into the same view the fine discriminations of the French authors, particularly regarding refraction, phosphorescence, specific gravity, electricity, chatoyement, and magnetism. The same may be said of the chemical characters. We do not know a more satisfactory and able view of the characters of minerals than Professor Cleaveland has exhibited.
We would however ask, whether, in enumerating the kinds of lustre, the term adamantine should not be explained, as it is not understood by people in general, while the terms denoting the other kinds are generally intelligible; whether in the enumeration of imitative forms, lenticular and acicular should not rather be referred to the laws of crystallization; whether reniform and mamillary are synonymous; whether sandstone, as being a mere aggregate of fragments, is a good instance of the granular fracture; whether in its natural state (at least the common ore of nickel) is ever magnetic, till purified, and whether cobalt is ever magnetic unless impure.
Professor Cleaveland's remarks on fracture are uncommonly discriminating and instructive, and would lead a learner to a just comprehension of this important point in the characters of minerals.
The section relating to the chemical characters is concise, and professedly proceeds upon the principle of selection. It might perhaps have been, to some extent, advantageously enlarged; although, it is true, the author refers us to the particular minerals for individual instances; still it might have been well to have illustrated the general principles by a few well-chosen instances, e. g. how, by the blowpipe, galena is distinguished from sulphuret of antimony; carbonat of lead from sulphat of barytes, or carbonat of lime; garnet from titanium; plaster of Paris from soapstone, &c.; and, among trials in the moist way, how by nitric acid and ammonia, iron pyrites is distinguished from copper pyrites; and how, by acids, sulphat of lime is known from carbonat of lime. As the acids are used principally for trials on the effervescence of carbonats, most of which form with sulphuric acid, insoluble compounds, we should doubt whether sulphuric acid is so advantageously employed as the nitric or muriatic, in such cases, on account of the clogging of the effervescence by the thick magena, produced by a recently precipitated and insoluble sulphat.
According to our experience, the nitric or muriatic acid, diluted with two or three parts of water, is most eligible.
With respect to the blowpipe: it is a convenience to have a mouth-piece of wood, or ivory, joined to a tube of metal, as Mr. Cleaveland recommends; and some authors direct to have the tube attached to a hollow ball, for the sake of condensing the moisture of the breath; but every thing which adds to the expense and complication of the instrument will tend to discourage its use; we have never found any difficulty in performing every important experiment with the common goldsmith's brass blowpipe; and are confident, that, after the learner has acquired the art, or knack, of propelling a continued stream of air from his mouth, by means of the muscles of the lips and cheeks, while his respiration proceeds without embarrassment through the nostrils, he will need no other instrument than the common blowpipe. Indeed it is a truly admirable instrument, instantly giving us the effect of very powerful furnaces, the heat being entirely under command, the subject of operation and all the changes in full view, and the expense and bulk of the instrument being such that every one may possess it, and carry it about his person.
The chapter on the principles of arrangement is worthy of all praise. This difficult subject is here discussed with such clearness, comprehensiveness, and candour, as prove the author to be completely master of his subject; and we are persuaded, that, on this topic, no author can be studied with more advantage. We forbear to extract, because the whole should be attentively perused in connexion, and scarcely admits of abridgement. We entirely agree with Professor Cleaveland, as we have already said, that the chemical composition of minerals is the only just foundation of their arrangement; that next in importance is the crystalline structure, including a knowledge of the primitive form, and integrant molecule; and last and least important, in fixing the arrangement, are the external characters: these last should be only provisionally employed, where the two first are not ascertained, or the second is not applicable. When the arrangement is once made, we may, however, and we commonly shall, in describing minerals, pursue precisely the reverse order; the external characters will usually be mentioned first, the crystalline characters next, and the chemical last of all. In description, the external characters are often the most valuable; if judiciously selected and arranged, they will always prove of the most essential service, and can rarely be entirely dispensed with.
With regard to the NOMENCLATURE of minerals, we feelingly unite with Professor Cleaveland in deploring the oppressive redundancy of synonymes. Few minerals have only one name, and usually they have several. With Count Bournon we agree, that the discoverer of a mineral has the exclusive right of naming it, and that the name once given should not be changed without the most cogent reasons. What then shall we say of the Abbé Haüy, of whom, whether we speak of his genius, his learning, his acuteness, his discoveries, his candour, and love of truth, or his universally amiable and venerable character, we can never think without sentiments of the highest respect and admiration? More than any modern writer he has added to the list of synonymes, often exchanging a very good name, derived perhaps from the locality or discoverer of a mineral, for one professedly significant, but connected with its subject by a chain of thought so slight, that considerable knowledge of Greek etymology, and still more explanation, is necessary to comprehend the connexion; and thus, after all, it amounts, with respect to most readers, only to the exchange of one arbitrary name for another. What advantage, for instance, has grammatite, alluding to a line often obscure, and still oftener wholly invisible, over the good old name tremolite, which always reminds us of an interesting locality; how is pyroxene better than augite, amphibole than hornblende, amphigene than leucite, or disthene than sappar. Some of the Abbé Haüy's names are, however, very happily chosen, especially where new discriminations were to be established, or errors corrected, or even a redundant crop of synonymes to be superseded by a better name. Epidote is an instance of the latter, and the new divisions of the old zeolite family into four species, mesotype, stilbite, analcime, and chabasie, afford a happy instance of the former. It were much to be wished, that by the common consent of mineralogists, one nomenclature should be universally adopted: for its uniformity is of much more importance than its nature.
In expressing our approbation of the principles of arrangement adopted by Professor Cleaveland, we have of course espoused those of his TABULAR VIEW, which is perhaps as nearly as the state of science will admit, erected upon a chemical basis, like that of Brongniart, to which it bears a close resemblance. Some of the subordinate parts, we could have wished had been arranged in a manner somewhat different. In the genus lime, it appears to us better to describe the species carbonat first; because, being very abundant, and its characters clear, it forms a convenient point of departure and standard of comparison, in describing the other species which have lime for their basis, and some of which are comparatively rare. The same remark we would make upon quartz, and its concomitant, pure silicious stones. There appears to us a high advantage in making these minerals clearly known first, before we proceed to those which are much more rare, and especially which are much harder, and possess the characters of gems. For example, if a learner has become acquainted with quartz, chalcedony, flint, opal, chrysoprase, and jasper, he will much more easily comprehend the superior hardness, &c. and different composition of topaz, sapphire, spinelleruby, chrysoberyl, and zircon, which we should much prefer to see occupying a later, than the first place in a tabular arrangement; and, although topaz, by containing fluoric acid, appears to be in some measure assimilated to saline minerals, it is in its characters so very diverse from the earthy salts, that we have fair reason to conclude that the fluoric acid does not stamp the character; and, as it bears so close a resemblance to the ruby and sapphire, which evidently derive their principal characters from the argillaceous earth, we perhaps ought to infer that this (the topaz,) does so too. Indeed Professor Cleaveland has sufficiently implied his own opinion, by giving these minerals a juxtaposition in his table, although the same reasons which induced the placing of the topaz next to the earthy salts, could not have justified the placing of the sapphire there. On these points we are not, however, strenuous; they are of more importance if the work be used as a text-book for lectures, than as a private companion. With respect to the completeness of Professor Cleaveland's tabular view, we have carefully compared it with the third edition of Jameson's mineralogy; and although a few new species, or sub-species, and varieties have been added in this last edition, they are in general of so little importance, that Professor Cleaveland's work cannot be considered as materially deficient; and the few cases in which it is so, are much more than made up by his entirely new and instructive views of American mineralogy, to which no parallel is to be found in any other book, and which give it peculiar interest to the American, and even to the European, reader.
In another edition, (which we cannot doubt will speedily be called for,) he will of course add whatever is omitted in this, and we should be gratified to see a good article on the subject of the ærolites or stones which have fallen from the atmosphere. This subject is one, in our view, of high interest; and although in strictness it may not claim a place in a tabular view of minerals, (we must confess, however, that we see no important obstacle to its being treated of under the head of native iron,) there can be no objection to its being placed in an appendix. The fall of stones from the atmosphere is the most curious and mysterious fact in natural history.
It may seem perhaps too trivial to remark, that the annexation of numbers, referring to the pages, would be a serious addition to the utility of the tabular view. Very few inadvertencies have been observed—the following may be mentioned: Amenia, in the State of New-York, is printed (by a typographical error we presume) Armenia; and Menechan, where the menechanite is found, is mentioned as occurring in Scotland, but it is in Cornwall.
Authors seem agreed that the black-lead ore is an altered carbonat, but they seem not to have been so well agreed as to the nature of the blue-lead ore. In the cabinet of Colonel Gibbs, there are specimens which appear satisfactorily to illustrate both these subjects. The black-lead is by the blowpipe alone reducible to metallic lead; there is one specimen in the cabinet referred to, which is blackened on what appears to have been the under side, and seemingly by the contact of sulphuretted hydrogen gas; that which was probably the upper part remains unaltered, and is beautiful white carbonat of lead; this appearance is the more striking, because the piece is large and full of interstices, by which the gas appears to have passed through. The blue ore is in large six-sided prisms of a dark blue or almost black colour; where the prisms are broken across, they present an unequal appearance; sometimes they are invested; and sometimes slightly, and at other times deeply, penetrated by sulphuret of lead, having the usual brilliant foliated fracture. The part which looks like sulphuret of lead is easily reducible by the blowpipe, but not the whole crystal, as authors appear to imply; for if that part of the crystal which does not present the appearance of galena is heated by the blowpipe flame, it is not reduced, but congeals into the garnet dodecahedron, with its colour unaltered: these crystals are therefore phosphat of lead, and they appear to be either an original mixture of phosphat and sulphuret of lead, or the phosphat has somehow in part given up its phosphoric acid, and assumed in its stead sulphur, perhaps from the decomposition of sulphuretted hydrogen.
Professor Cleaveland will, of course, add new localities, even foreign ones, where they are interesting, and domestic ones, where they are well authenticated. Among the former, we trust he will mention the lake of sulphuric acid contained in the crater of Mount Idienne, in the Province of Bagnia Vangni, in the eastern part of Java, and also the river of sulphuric acid which flows from it and kills animals, scorches vegetation, and corrodes the stones.[10] Among American localities, we beg leave to mention violet fluor spar, abundant and very handsome, near Shawnee Town, on the Ohio, in the Illinois Territory, and galena, of which this fluor is the gangue;—sulphat of magnesia, perfectly crystallized, in masses composed of delicate white prisms, in a cave in the Indiana Territory, not very remote from Louisville, in Kentucky; it is said to be so abundant that the inhabitants carry it away by the wagon load;—pulverulent carbonat of magnesia, apparently pure, found by Mr. Pierce at Hoboken, in serpentine, where the hydrate of magnesia was found;—chabasie, agates, chalcedony, amethyst, and analcime, at Deerfield, by Mr. E. Hitchcock;—agates in abundance at East-Haven, near New-Haven, in secondary greenstone, like the above-named minerals at Deerfield;—saline springs, covered with petroleum, and emitting large volumes of inflammable gases, numerous in New-Connecticut, south of Lake Erie;—magnetical pyrites, abundant in the bismuth vein, at Trumbull, Connecticut:—very brilliant fine-grained micaceous iron, in large masses near Bellows' Falls; yellow foliated blende, in Berlin, Connecticut, and near Hamilton College—the latter discovered by Professor Noyes; it is in veins in compact limestone;—red oxid of titanium, often geniculated, at Leyden, in Massachusetts, discovered by Mr. E. Hitchcock;—red oxid of titanium, in very large crystals and geniculated, imbedded in micaceous schistus, at Oxford, 20 miles north from New-Haven;—silicious petrifactions of wood, abundant in the island of Antigua, recently brought by Mr. Pelatiah Perit, of New-York;—sulphuret of molybdena, at Pettipaug, and at East-Haddam, Connecticut;—prehnite abundant and beautiful, in secondary greenstone, at Woodbury, 24 miles north of New-Haven, discovered by Mr. Elijah Baldwin;—black oxid of manganese, in great abundance, and of an excellent quality, near Bennington, Vermont, and plumose mica, in a very fine graphic granite, in a hill two miles north of Watertown, Connecticut.
The introduction to the Study of Geology, deserves a more extended series of remarks than it would now be proper to make, after so full a consideration of the previous parts of the work.
Professor Jameson's elaborate exposition of the Wernerian system, is too full, and too much devoted to a particular system, for beginners: the sketches of geology contained in the systems of Chemistry by Murray and Thomson, and in Phillips's mineralogy, are too limited, although useful: the excellent account of the Wernerian system, contained in an Appendix to Brochant's Mineralogy, has, we believe, never been translated; and we need not say that Professor Playfair's illustrations of the Huttonian Theory, De Luc's Geology, and Cuvier's Geology, are not well adapted to the purposes of a beginner; neither is Delametherie's, nor has it been translated. An introduction to geology was, therefore, hardly less needed than one to mineralogy. Professor Cleaveland has performed this difficult duty with great ability, and has brought this interesting branch of science fairly within the reach of our students.
Although adhering substantially to the Wernerian arrangement of rocks, he has, so to speak, blended Werner's three classes of primitive, transition, and secondary rocks, into one class; and where the same rock occurs in all the three classes, or in two of them, he mentions it in giving the history of the particular rock. This method simplifies the subject very much to the apprehensions of a learner. A rigid Wernerian would probably revolt at it, but the distinctions of Mr. Werner may still be pointed out, and, we should think, ought to be, at least by all teachers.
In Mr. Cleaveland's account of the trap rocks, we should almost imagine that some typographical error had crept into the following paragraph:
"But in modern geological inquiries, the word trap is usually employed to designate a simple mineral, composed of hornblende nearly or quite pure, and also those aggregates in which hornblende predominates. Hence, the presence of hornblende, as a predominating ingredient, characterizes those MINERALS to which most geologists apply the name trap."
Now, it is not accordant with our apprehensions that trap is ever at the present time employed to designate a simple mineral, nor has Professor Cleaveland himself used it in his tabular view, or in his description of simple minerals. In our view, it is the classical word of modern geology, to designate that description of rocks in which hornblende predominates, and perhaps a few others of minor importance usually associated with them. It is true, a rock composed of pure hornblende may be called trap, but it is not true, vice versa, that this rock, considered in its character of a simple mineral, is called trap. If our views are correct, the section which is headed trap or hornblende, should be trap or hornblende rocks, and greenstone should come in as a subdivision, and not form a distinct section. With these alterations, and with the substitution of rock in the first, and rocks in the second instance, in the paragraph above quoted, instead of mineral and minerals, we apprehend the view of this family of rocks would be much more clear, and a degree of confusion, which learners now experience from the paragraph, would be prevented. If we are wrong, we are sure Professor Cleaveland will pardon us; if right, his candour will readily admit the correction.
As to the manner in which the work of Professor Cleaveland is executed, the remarks which we already made, have in a good degree anticipated this head.
We cannot, however, dismiss the subject without adding that, in our opinion, this work does honour to our country, and will greatly promote the knowledge of mineralogy and geology, besides aiding in the great work of disseminating a taste for science generally. Our views of the plan we have already detailed. The manner of execution is masterly. Discrimination, perspicuity, judicious selection of characters and facts, and a style chaste, manly, and comprehensive, are among the characteristics of Professor Cleaveland's performance. It has brought within the reach of the American student the excellencies of Kirwan, Jameson, Haüy, Brochant, Brongniart, and Werner; and we are not ashamed to have this work compared with their productions. In our opinion Professor Cleaveland's work ought to be introduced into all our schools of mineralogy, and to be the travelling companion of every American mineralogist.
We trust that all cultivators of mineralogy and geology in this country, will willingly aid Professor Cleaveland in enlarging his list of American localities for a second edition; and we hope that he will repay them, at a future day, by giving us a distinct treatise on geology, with as particular a delineation as possible of the geological relations of the great North American formations. Mr. Maclure has, with great ability, sketched the outline; but much labour is still needed in filling up the detail.