of gold, a considerable quantity of tin and iron, also diamonds and most of the other precious stones, are concealed in sand, clay, &c.,and obtained by washing.(q.v.) (Forthe mineral wealth of the U. States, see that article; also the articles on the separate states, particularly Illinois, Michigan,and Missouri, for lead, and Pennsylvania for coal, &c.) Mining. The science of mining includes the scientific knowledge requisite for opening and working mines, as well as for preparing ores for use. It requires a knowledge of mineralogy and geology (q. v.), and of the different processes requisite in mine working, for searching after useful minerals, bringing them to the surface, mechanically and chemically separating them, and removing all difficulties that occur in the course of the work, the sinking of shafts, propping up the superincumbent earth, so as to give security to the miners, &c. This security is obtained partly by the form of the pits, by propping with stones, by suffering pillars of stone to remain standing, by supports of timber or masonry. Mining also includes the building of machinery, the preparation of the ore for smelting, or the mechanical separation of the useless minerals from the useful, as well as of the different kinds of the latter from each other. The preparation of the ore consists, in the first place, in breaking asunder the larger pieces, and then purifying them, by means of water, from the earth which adheres to them; in the separation of the coarser substances from the finer, by means of a sieve, that moves up and down in water; in the breaking of the ore in stamping-mills, which consist either of hammers or iron cylinders, driven up and down, and in the separation of the finely interspersed metal from the stone or earth, with which it is surrounded, by washing the broken ore in troughs or on inclined tables crossed by a current of water; the heavier ore remains, while the lighter earthy and stony substances are carried away by the water. Mining also includes the final purification of the ore, by means of acids, by amalgamation, by fusion, &c.

Mining Academies. In Germany, where the science of mining had its origin, acad-emies exist, in which young men are instructed in the science of mining, and educated as superintendents of mines, founderies or salt-works. These institutions have been imitated in other countries. Such academies exist at Freiberg in Saxony, at Schemnitz in Hungary, at Petersburg, at Paris, at St. Etienne, &c.

MINERAL CAOUTCHOUC.

men.)

(See Bitu

MINERALOGY, or the NATURAL HISTORY of the Mineral KINGDOM, considered as a pure science, is of very recent date. The observations made at first related simply to the usefulness of minerals to the purposes of society, and it was not before the lapse of many ages that they came to be investigated on account of their great variety and the beautiful arrangements of which they are susceptible. The Oputa and μeraλλeura of Aristotle evince no valuable observations on the part of that philosopher concerning minerals, and are chiefly mentioned by him because he believed the former to be derived from the earth, and the latter from water. The allusions to mineral substances found in the writings of Theophrastus, Pliny, Dioscorides and Galen are of more interest to the antiquarian and philologist than to the natural historian. No attempt to classify these bodies was made previous to the introduction of alchemy into Europe by the Arabians; and to Avicenna belongs the merit of the first arrangement. He divided minerals into stones, metals, sulphureous fossils and salts-a division which was generally adopted by the chemists of those times, though opposed by the naturalists, who confined their investigations to the characters derived from the external forms of minerals and their supposed medicinal virtues, but without deriving from them any just grounds of classification. According to one or the other of these vicious methods was the science of mineralogy treated, down to the 16th century, its cultivators either implicitly adopting the ideas of the chemists, or announcing themselves as little better than mere empirical collectors of curiosities. Agric ola (who was born in 1490, and died in 1555) directed his views to the uniting these two classes, though he inclined more strongly to the side of the scholiasts than to that of the chemists. All minerals (corpora subterranea) are divided by him into simple, or such as consist of homogeneous particles, and compounded, or such as are formed of heterogeneous parts, taken in a mineralogical acceptation of the terms. The minerals belonging to the former of these divisions are found in four different forms, viz. 1. terra; 2. succus concretus; 3. lapis; 4. metallum. Terra he defines as corpus fossile quod potest manu subigi, cum fuerit aspersum humore, aut ex quo cum fuerit madefactum, fit lutum. These earths he divides partly according to some external characters, partly after their localities,

in cases where their names are derived from the countries or places in which they are found:-Succus concretus est corpus fossile siccum et subdurum, quod aquis aspersum aut non mollitur, sed liquescit, aut, si mollitur, multum vel pinguitudine differt a terra, vel materia ex qua constat. The fossils of this class Agricola divided into macra and pinguia. The former consists of a juice, partly mixed with earth (sal nitrum), partly with metal (chrysocolla, arugo, ferrugo, cæruleum), partly mixed both with earth and metal (atramentum, sutorium, alumen, &c.); to the latter he refers sulphur, bitumen, sandarach, and auripigmentum. The stones are the third class of Agricola's system. Lapis est corpus fossile siccum et durum, quod vel aqua longinquo tempore vix mollit, ignis vehemens redigit in pulverem; vel non mollit aqua, sed maximo ignis liquescit calore. The stones are subdivided into lapis, gemma, marmor, and saxum. His definition of metals, being his fourth class, is corpus fossile natura vel liquidum vel durum quidem, sed quod ignis liquescit calore. He enumerates 10 metals. The last class of Agricola's system comprehends mixed and compound fossils:-1. Mixtures of stones and juices (succi); 2. of earth and metal; 3. of stone and metal; 4. of juice, stone and metal. To the second and third divisions he refers the various ores. (A translation of Agricola's system into German was published, with considerable additions, by Lehmann, at Freyberg, in 1809.) Most of the writers on mineralogy who succeeded Agricola until the middle of the following century adopted his system, occasionally making some trifling alterations, in conformity to the slow progress of chemistry. Becher (whose Physica Subterranea was published in 1667) made the first important innovation upon the classification of Agricola. He considered water and earth as the remote, and vitreous, inflammable and mineral earths (sal, sulphur, mercurius) as the proximate constituent parts of all minerals, which he accordingly arranged under three classes; the first comprehending those stones in which the vitreous earth constitutes the principal ingredient; the second and third class containing the substances in which the two remaining earths predominate. Bromelius, who published a book entitled Catalogus Rerum Curiosarum (Gothenburg, 1698), referred sulphur and the bituminous substances to the same class, which he called sulphurea and pinguia. Magnus von Bromel, a Swede, who was the pupil of Boerhaave, published a system

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of mineralogy-Inledring til Kunscah om Mineralier, &c. (Stockholm, 1730), in which he not only availed himself of all the improvements made by his predecessors, but also proposed a new chemical division of stony substances into such as are refractory (apyri), or calcinable, or vitrescible in the fire, to which were added the figured stones (figurati). After Von Bromel, the great Swedish reformer in natural history appeared, whose admirable views respecting the philosophy of the natural sciences have contributed more to the perfection of our science than the labors of all who preceded him; and yet Linnæus appears to have possessed but very little knowledge of minerals, but the complete success with which he applied the method of natural history to the vegetable kingdom rendered it easy for subsequent naturalists to apply his principles to the mineral kingdom. Linnæus, too, has the merit of calling the attention of naturalists to the important characters derived from the diversity of crystallization. Mineralogy, however, remained, from the time of Linnæus to that of Werner, almost exclusively in the hands of chemists, who appear to have regarded the science in no other light than as an appendage of chemistry, and who, while they degraded all regard to the natural properties of minerals, believed that chemical knowledge was alone capable of affording the basis of the classification, nomenclature and diagnosis of the mineral kingdom. To this class of the cultivators of mineralogy bolonged Henkel, Pott, Wallerius and Cronstedt. In 1774, Werner published his work On the external Properties of Minorals (Von den äussern Kennzeichen der Fossilien) a work of great merit and value at that juncture, as it served to call the attention of naturalists to the only correct method of arriving at a knowledge of this department of nature. The external characters of minerals had before been almost wholly neglected; in this work they were described with uncommon minuteness, though they were employed by him in his system without a just regard to their relative importance. The greatest defect, however, in the views of Werner arose from his reluctance to ascertain the properties of minerals through the aid of instruments. He scarcely availed himself of any other means than such as were derived directly through the eye, the hand, and the tongue. Hence those characters, depending upon the value of angles and different degrees of hardness and specific gravity, and which are now acknowledged

to be of the highest value in mineralogy, were turned to comparatively little account. For a knowledge of Werner's system of mineralogy, we are indebted to his translation of Cronstedt's mineralogy (to which he subjoined notes), to his catalogue of the mineral collection of M. Pabst von Ohain, and to several memoirs in the Bergmannische Journal. In addition to these sources, several expositions of his system have been made by his pupils, the best of which is that published by professor Jameson. The fundamental principle laid down by Werner in the classification of minerals, is their natural affinity, which he allows to be founded on the chemical nature of their component parts. These he distinguishes into essential and accidental component parts, of the former of which only does he take notice in his arrangement. The essential component parts are subdivided into predominant and characteristic ones, and generally the characteristic happen to be, at the same time, the predominant constituents. His classes are four, which are founded on what he calls the fundamental constituent parts, viz. the earthy, saline, inflammable and metallic, each class being named after that fundamental constituent part which predominates in and characterizes it. Thus he derives his classes of earths, salts, inflammables and metals. These classes are subdivided into genera, which are founded upon the variety in the component parts of the minerals comprehended in each class, there being as many genera as there are predominating, or, at least, characteristic constituent parts discovered in their mixture. But neither Werner nor his pupils have been very strict in adhering to this rule for the formation of the genera, these, as well as the species, having more frequently been established by them upon the natural instead of the chemical properties. Werner's system was essentially deficient in respect to unity, in consequence of the regard which he allowed to the chemical relations of minerals, and, like those which preceded his time, it was rather a mixture of chemistry and mineralogy than the representation of a pure science, an objection which applies with scarcely undiminished force to the next great system, which was presented to the mineralogical world by Hauy at the commencement of the present century. Mineralogy, however, is under immense obligations to the abbé Haiy for his researches respecting the geometrical character of minerals. His labors, connected with crystallography, gave an

entirely new aspect to the science, and communicated to its results a degree of that precision and certainty which belong to geometry. Still his want of knowledge of the principles of natural history prevented him from remedying the faults of his predecessors. His system, like that of Werner, is founded upon two sciences, and consequently wants the order, the connexion and consistency of parts which belong to the idea of a science. He defines a species in mineralogy to be "an assemblage of bodies,the integrant molecules of which are similar to each other, and have the same composition." The following outline of Hauy's system is taken from his Traité de Minéralogie (Paris, 1822):— Class I. Free acids. Class II. Metallic substances, but destitute of a metallic appearance. This class contains eight genera, viz. lime, barytes, strontites, magnesia, alumine, potash, soda, and ammonia; and to it is subjoined an appendix, consisting of one order characterized by the presence of silex in all its compounds, and which embraces a larger number of species than the whole class to which it is appended. Class III. True metallic substances. This class contains 18 genera, characterized by the different metals. Class IV. Unmetallic, combustible substances.-In proceeding to notice the labors of professor Mohs, we come to an era in the history of mineralogical science. This eminent philosopher, no less distinguished as a cultivator of the mathematics than of mineralogy, published at Dresden, in 1822, bis Grundriss der Mineralogie, a work replete with new and philosophical views of our science. His first object is to fix the exact limits of mineralogy, and to exclude from it a variety of foreign matter belonging to other sciences, which had before rendered it a heterogeneous mass of information, incapable of derivation from constant principles by any regular process of reasoning. He then proceeds to develope the science under the following heads:-1. terminology; 2. theory of the system; 3. nomenclature; 4. characteristic; 5. physiography. Under the first of these he explains those properties of minerals which manifest no change, either in the properties themselves, or in the substances which possess them during their observation or examination, and which properties alone form the object of consideration in mineralogy, viewed as a pure science. They had before been treated of under the denomination of external or physical characters, though, from the stress which had been laid upon chem

ical characters, the greater part of them had been but very imperfectly determined; and this part of the subject is called terminology, because, besides the general investigation of those properties, it embraces also the explanations of the expressions which, for the sake of precision, are used in a determinate and peculiar sense. Decomposed and imperfectly formed minerals, or those which are destitute of several of the properties peculiar to these bodies, are not regarded as suitable objects for the consideration of the science; in which respect they are treated like mutilated, defective or monstrous plants or animals in botany and zoology. And in order to study the productions of the mineral kingdom in their purest state, Mohs takes notice of those properties which belong to minerals occurring in single individuals, separately from those which belong to several individuals of the same quality, formed in a common space, one being the support of, or at least contiguous to, the other,-of the former of which only does he make use in the determination of the species, while he pays no attention to the properties of minerals composed of individuals belonging to different species (mixed minerals), these last falling within the province of geology. This is a distinction of the highest importance and utility, in rendering all the departments of mineralogy mutually consistent, though one which had been almost wholly disregarded by all his predecessors. According to this system, the individual of the mineral kingdom, or the simple mineral, is the sole object of mineralogy, and the natural properties of the simple mineral are the only ones to which, in this science, we ought to direct our attention. It will be obvious, therefore, that all information thus derived must be of one kind, and consequently its aggregate conformable to the logical idea of a science. Mohs has particularly distinguished himself in treating of that part of terminology which relates to the regular forms of minerals. The fundamental forms, from which he derives all the occurring forms among minerals, are but four in number, viz. the scalene four-sided pyramid, the isosceles four-sided pyramid, the rhombohedron, and the hexahedron; and the geometrical constructions by which he illustrates the simple forms capable of appearing in the individuals of one and the same species, or which may produce combinations with one another, entitle him to the first rank as a crystallographer. The natural-historical properties of compound minerals are

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treated of in the most precise manner, the previous neglect of which had involved the science in numerous important errors. But one of the greatest improvements under this head was the establishment of an accurate scale for the degrees of hardness. This was effected by choosing a certain number of suitable minerals, of which every preceding one is scratched by that which follows it, while the former does not scratch the latter; and the degrees of hardness are expressed by means of numbers prefixed to the different individuals of the scale. Thus

1 expresses the hardness of tale;

2

3

4

5

corundum; diamond.

10 The second general head under which mineralogy is developed, according to Mohs, is the theory of the system, which contains the reasoning or philosophical part of the science. It determines the idea of the species; fixes the principle of classification; and upon the idea of the species it founds, according to this principle, the ideas of the genus, the order, and the class; and lastly, by applying all these ideas to nature, the outline of the system thus constructed is furnished with its contents, in conformity to our knowledge of the productions of nature, as obtained from immediate inspection. The idea of the species is here, for the first time, scientifically obtained, and is founded upon all the series of natural properties without the introduction of any considerations foreign to natural history, which had proved the source of the contamination that the science had before suffered from heterogeneous principles. The principle of classification consists in the resemblance of natural properties, since in every science the classification must rest upon such relations as are objects of the science. On the different degrees of resemblance are founded the higher ideas of the theory of the system. An assemblage of species connected by the highest degree of natural-historical resemblance is termed a genus; an assemblage of similar genera an order; of similar orders a class; and the collection of these ideas conformably to the degree of their generality, and applied to the productions of the mineral king

dom, constitutes the mineral system. The mineral system is therefore the systematic exhibition of the natural resemblance as observable in the mineral kingdom, or of the connexion established by nature among its products by means of this resemblance. For this reason it is called the natural system, because, in fact, it expresses nature in this very remarkable relation. The third idea of the science, as developed by Mohs, is its nomenclature, which relates to the connexion of its unities with certain words, through which the ideas and representations may be so expressed as to be conveniently applied in writing and speaking. Nothing is better calculated to furnish us with an idea of the situation in which mineralogy had before been placed, than the consideration of its former nomenclature, and of the method employed in giving new names. Those were regarded as the best which had no signification, as is obvious from the frequency with which designations were adopted derived from colors, persons, localities, and other accidental circumstances; and, as respects those names which referred to the connexion of the different minerals in regard to their resemblance, these were still more objectionable, since the connexion expressed by them was either entirely incorrect, or without reference to the system in which the names were applied. The nomenclature therefore required to be wholly remodelled, none deserving of the name having before existed, the reason of which appears to have been that mineralogy had not before been treated as a science, but as an aggregate of various kinds of information, a sort of mixture which would admit every kind of knowledge to be introduced, and in which nothing could be placed wrong, because in such a disposition there could be no order. The order is the highest idea expressed in the nomenclature of Mohs, and in the selection of the names of the orders he has invented but two which are entirely new, having employed as many designations from ancient mineralogy as would answer the purpose. The names receive their signification in agreement with the ideas of the orders; thus pyrites embraces the minerals hitherto called by that name. A mineral which may with propriety bear the name of a metal must really be a metal, or it must present the properties peculiar to metals. Mica signifies a mineral which may be cleaved with facility into thin, shining lamine; the order mica therefore contains only such species as present cleavage in a

high degree of perfection. The name of the genus is a compound name, formed by connecting another word with the name of the order. Thus we have lead glance, augite spar, iron pyrites. The generic name also refers to the properties of the genus, and expresses, as much as possible, some striking feature of its resemblance with other bodies. Such is the name garnet-blende. The genus designated by this name belongs to the order blende; the individuals which it contains very often look like garnet. The denomination of the species is produced by the nearer restriction of the generic name by an adjective. The adjective with which the species is designated within its genus is taken from its natural properties, and in general refers to one of those properties of the species which is most useful in distinguishing it from other species of the same genus; hence the systems of crystallization and the relation of cleavage are the most frequently employed,-examples of which are hexahedral, prismatic, rhombohedral iron pyrites; rhombohedral, octahedral, dodecahedral, prismatic iron ore, &c.— The great advantage of the systematic nomenclature is, that the names produce an image of the objects to which they refer, which the trivial nomenclature can never do; for example, if we hear the name peritomous titanium ore, and have only an idea of the order ore, this at once will produce a general image of the species, which will be still more restricted if we have some idea of the genus titanium ore; but, on the other hand, if we hear the name rutile, and do not know the species itself to which it belongs, we never can imagine any thing like a representation of the object, though, for the rest, our knowledge of mineralogy may be very extensive. The terminology, the theory of the system, and the nomenclature, form the constituents of theoretical mineralogy. Practice, or the application of it to nature, requires the characteristic, the object of which is, to furnish us with the peculiar terms or marks, by which we are able to distinguish objects from each other, so far as they are comprehended in the ideas established by the theory of the system. In order to find the name of a mineral when its properties are ascertained, we make use of the characteristic, which consists of an assemblage of general ideas, corresponding to the system, and expressed by single distinctive marks. With these ideas are connected the names and denominations as far as the nomenclature extends and requires, not above the order,