Page:The American Cyclopædia (1879) Volume XI.djvu/608

590 MINERALOGY Berzelius some time before 1816 (French edi- tion, 1819) its first decisive impetus. That chemist looked upon mineralogy as properly a mere branch of his own favorite science. He explained mineral as he explained other com- pounds on the dualistic theory, according to which they were made up of an electro-posi- tive and an electro-negative element or radical. His classification included two great groups, the first composed of native metals and bina- ries, not containing oxygen; and the second of electro-positive and electro-negative oxides, hydrates, silicates, alumina-silicates, tungstates, borates, carbonates, &c. ; each acid, or each plectro-negative element, having its own divi- sion as now. He introduced into the science the exact methods of chemistry, and urged the necessity of constant analysis, so that the ex- isting mode of mineralogical study is known as the Berzelian, improved by the addition of crystallography and the special study of ex- ternal marks. "While the science was thus re- ceiving constant accessions in Germany and Sweden, the French mineralogists were also working out various schemes of classification. Unable to produce a harmonious arrangement on any simple plan, they adopted a mixed system. Brongniart, in his Traite elemen- taire (1807) and Tableau des especes mine- rales (1833), classified the earthy minerals ac- cording to the negative element, and the me- tallic ones according to the positive element. He had two grand divisions, the inorganic and organic. In the first were included 20 " min- eralizers," such as oxygen, hydrogen, and sul- phur ; the second class, metaux autopsides, con- tains true metals and their compounds ; while the third class, metaux heteropsides, contains other bases and forms two orders, one of com- pounds without, and one of those with an acid. Beudant, in his Traite de mineralogie (1824), endeavored to restrict the classification of min- erals to their chemical reactions. He formed three grand genera, based upon the character- istic negative element. Gazolytes contained a negative element capable of forming stable gaseous compounds with oxygen, hydrogen, or fluoric acid, and included carbon, silicon, chlo- rine, &c. Leucolytes contained a negative ele- ment which does not form such stable gaseous compounds, but gives colorless solutions with acids. Chroi'colytes, on the other hand, give colored solutions with acids. Though this ar- rangement supplanted that of Haiiy, the group- ings of minerals formed under it were of the most heterogeneous character. Dufre"noy in 1844 published the first edition of a treatise in which a mixed system was again presented. He recognized natural groups in some of which the bases bore the important part, and in others the acids. In these mixed systems the bases are the real ground of classification, but the importance and number of the silicates, and the fact that the base plays a secondary part in most of them, compel an exception to be made in their favor in any scheme where the bases are made the characteristic elements. The French school has always been distinguished for eminence in crystallographic and physical researches, the latest development of which is to be seen in Descloizeaux's admirable investiga- tions into the optical properties of minerals, by which the recognition of many obscure species has been greatly aided. The mixed classifica- tion of the French, however, has been rejected, partly for its incongruity and partly because the new chemical methods have been altogeth- er in favor of the Berzelian mode. In 1840 Gustav Rose of Berlin published a work on crystallography, in which the six crystalline systems formed the general divisions, in each of which the minerals were arranged in genera and species, according to their chemical com- position. In 1852 he published his Krystallo- ckemisches Miner alsy stem, in which the chem- ical composition is used both to determine the general arrangement and to fix the individ- ual species, which are grouped into genera by their crystallographic characters. His method of arrangement was: 1, simple bodies; 2, com- pounds of sulphur, selenium, tellurium, arse- nic, and antimony ; 3, compounds of chlorine, fluorine, iodine, and bromine ; 4, oxygen com- pounds. Raminelsberg, in several works, and especially in his Handbuch der Mineralchemie, has paid great attention to the constitution of minerals, their relationships, the laws regula- ting their formation, and similar questions. K. G. Bischof, in his Lelirbuch der chemischen und physikalischen Geologie, entered into the genesis of minerals, and, though his views have been frequently rebutted, he exerted a marked influence upon the progress of the science. Germany continues to be one of the most ac- tive fields for the advancement of this science. Tschermach, Leonhardt, Hessenberg, and oth- ers issue periodical reviews of progress, miner- alogical magazines are published, and a great number of works on the science in all its branches are constantly issued. The German school now probably includes a greater num- ber of distinguished names than any other, though the science is rapidly advancing in all countries. In the United States mineralogy had been but little cultivated before the begin- ning of the present century. A few collections of minerals had been brought from Europe, but the treatises of Kirwan and Jameson were almost the only works that could be consulted with reference to them, and very few were acquainted with these. In 1816 Prof. Parker Cleaveland of Bowdoin college published "An Elementary Treatise on Mineralogy and Geol- ogy," which was well received both in Ameri- ca and in Europe as a work of scientific impor- tance, and particularly useful for the informa- tion it afforded respecting American miner- als. The author, following the general plan of Brongniart at that time, sought to unite with the precise descriptive language of the system of Werner the chemical classification of the French mineralogists. His work was