classification

science

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Assorted References

  • study by Müller
    • In Johannes Müller

      …specimens; he devised an improved classification of fish and, based on an ingenious analysis of vocal organs, did the same for singing birds. For several years he concentrated on the lowest forms of marine vertebrates, the Cyclostomata and Chondrichthyes. He painstakingly described the structures and complex development of members of…

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application in

    • archaeology
      • Pachacamac, Peru
        In archaeology: Classification and analysis

        The first concern is the accurate and exact description of all the artifacts concerned. Classification and description are essential to all archaeological work, and, as in botany and zoology, the first requirement is a good and objective taxonomy. Second, there is a…

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    • asteroids
      • asteroid distribution between Mars and Jupiter
        In asteroid: Classification of asteroids

        In the mid-1970s astronomers using information gathered from studies of colour, spectral reflectance, and albedo recognized that asteroids could be grouped into three broad taxonomic classes, designated C, S, and M. At that time they estimated that about 75 percent belonged to…

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      • asteroid distribution between Mars and Jupiter
        In asteroid: Composition

        1 micrometres (μm)—is used to classify asteroids into various taxonomic classes. If sufficient spectral resolution is available, especially extending to wavelengths of about 2.5 μm, those measurements also can be used to infer the composition of the surface reflecting the light. That can be done by comparing the asteroid data…

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    • chemical compounds
      • methane molecule
        In chemical compound: Classification of compounds

        Chemical compounds may be classified according to several different criteria. One common method is based on the specific elements present. For example, oxides contain one or more oxygen atoms, hydrides contain one or more hydrogen atoms, and halides contain one or more…

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    • climatology
      • Map of climatic zones.
        In climate classification

        Such classification schemes rely on efforts that sort and group vast amounts of environmental data to uncover patterns between interacting climatic processes. All such classifications are limited since no two areas are subject to the same physical or biological forces in exactly the same way. The…

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    • concept formation
      • In concept formation

        …experiences into general rules or classes. With regard to action, a person picks up a particular stone or drives a specific car. With regard to thought, however, a person appears to deal with classes. For instance, one knows that stones (in general) sink and automobiles (as a class) are powered…

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    • religious studies
      • Charles Sprague Pearce: Religion
        In classification of religions: Conclusion

        The classification of religions that will withstand all criticism and serve all the purposes of a general science of religions has not been devised. Each classification presented above has been attacked for its inadequacies or distortions, yet each is useful in bringing to light certain aspects…

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    role in

      • periodic law
        • In periodic table: History of the periodic law

          …of chemical knowledge soon necessitated classification, for on the classification of chemical knowledge are based not only the systematized literature of chemistry but also the laboratory arts by which chemistry is passed on as a living science from one generation of chemists to another. Relationships were discerned more readily among…

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      • problem of universals
        Quick Facts
        (Latin), German:
        Georg Bauer
        Born:
        March 24, 1494, Glauchau, Saxony [Germany]
        Died:
        November 21, 1555, Chemnitz (aged 61)

        Georgius Agricola (born March 24, 1494, Glauchau, Saxony [Germany]—died November 21, 1555, Chemnitz) was a German scholar and scientist known as “the father of mineralogy.” While a highly educated classicist and humanist, well regarded by scholars of his own and later times, he was yet singularly independent of the theories of ancient authorities. He was indeed among the first to found a natural science upon observation, as opposed to speculation. His De re metallica dealt chiefly with the arts of mining and smelting, and his De natura fossilium, considered the first mineralogy textbook, presented the first scientific classification of minerals (based on their physical properties) and described many new minerals and their occurrence and mutual relationships.

        Life

        Agricola was born of obscure parentage. From 1514 to 1518 he studied classics, philosophy, and philology at the University of Leipzig, which had recently been exposed to the humanist revival. Following the custom of the times, he Latinized his name to Georgius Agricola. After teaching Latin and Greek from 1518 to 1522 in a school in Zwickau, he returned to Leipzig to begin the study of medicine but found the university in disarray because of theological quarrels. A lifelong Catholic, he left in 1523 for more congenial surroundings in Italy. He studied medicine, natural science, and philosophy in Bologna and Padua, finishing with clinical studies in Venice.

        For two years Agricola worked at the Aldine Press in Venice, principally in preparing an edition of Galen’s works on medicine (published in 1525). In this task he collaborated with John Clement, who had been Thomas More’s secretary during the writing of Utopia. More’s book may well have influenced Agricola to concern himself later with the laws and social customs of the Saxon mining district. In Italy he also met and won the friendship of the great scholar Erasmus, who encouraged him to write and later published several of his books. (Erasmus wrote an introduction to Agricola’s first book, the mineralogical treatise Bermannus. Agricola shared that honour only with More and three other scholars.)

        Pre-historic cave painting in the Lascaux cave in Montignac, France
        Britannica Quiz
        Quiz: Ancient Illustrations Showing Us the Way

        In 1526 Agricola returned to Saxony, and from 1527 to 1533 he was town physician in Joachimsthal, a mining town in the richest metal-mining district of Europe. Partly in the hope of finding new drugs among the ores and minerals of his adopted district (a hope eventually to be disappointed), he spent all his spare time visiting mines and smelting plants, talking to the better-educated miners, and reading Classical authors on mining. These years shaped the rest of his life and provided the subject matter for most of his books, beginning with Bermannus; sive, de re metallica (1530), a treatise on the Ore Mountains (Erzgebirge) mining district. There are indications that he owned a share in a silver mine.

        Agricola appears not to have been particularly distinguished as a physician, though in this pursuit he made use of direct observation rather than of received authority. He introduced the practice of quarantine into Germany, and his books make many references to miners’ occupational diseases. In 1533 he became town physician in Chemnitz, where he remained to the end of his life.

        In 1546 Duke Maurice, elector of Saxony, appointed Agricola burgomaster (mayor) of Chemnitz. He also served as an emissary in the Protestant ruler Maurice’s ambiguous negotiations with Charles V, the Holy Roman emperor. The religious wars of the period rapidly eroded the tolerance that had hitherto prevailed in the Protestant German states, a tolerance from which Agricola had benefited.

        Apart from his diplomatic role, Agricola took only limited interest in politics. His youthful “Turkish Speech” of 1529, a vigorous call to the Holy Roman emperor Ferdinand I to undertake a war against the Turks, was a patriotic hymn to Germany and a call to political and religious unity. It made a great impression on the public and was often reprinted.

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        Chief works

        Agricola’s magnum opus, for which the treatise Bermannus was a prelude, was De re metallica, published posthumously in 1556. In it, among other things, Agricola surveys historical and Classical allusions to metals and assesses the content and distribution of metal mines in antiquity. He treats the pattern of ownership and the system of law governing Saxon mines, together with the details of their day-to-day labour management. He was mainly concerned, however, with mining and metallurgy, and he discussed the geology of ore bodies, surveying, mine construction, pumping, and ventilation. There is much on the application of waterpower. He describes the assaying of ores, the methods used for enriching ores before smelting, and procedures for smelting and refining a number of metals, and he concludes with a discussion of the production of glass and of a variety of chemicals used in smelting operations.

        In De natura fossilium (the book on which rests his right to be regarded as the father of mineralogy), Agricola offers a classification of minerals (called “fossils” at that time) in terms of geometric form (spheres, cones, plates). He was probably the first to distinguish between “simple” substances and “compounds.” In Agricola’s day, chemical knowledge was almost nonexistent, and there was no proper chemical analysis (other than analysis of ores by the use of fire), so the classification of ores was necessarily crude.

        In several other books, notably De natura eorum quae effluunt ex terra (1546) and De ortu et causis subterraneorum (1546), Agricola describes his ideas on the origin of ore deposits in veins and correctly attributes them to deposition from aqueous solution. He also describes in detail the erosive action of rivers and its effect in the shaping of mountains. His readiness to discard received authority, even that of Classical authors such as Aristotle and Pliny, is impressive.

        Agricola’s scholarly contemporaries regarded him highly. Erasmus prophesied in 1531 that he would “shortly stand at the head of the princes of scholarship.” Later Goethe was to liken him to Francis Bacon. Melanchthon praised his “grace of presentation and unprecedented clarity.” The mining engineer Herbert Hoover (later U.S. president), who translated De re metallica into English in 1912, regarded Agricola as the originator of the experimental approach to science, “the first to found any of the natural sciences upon research and observation, as opposed to previous fruitless speculation.”

        Robert W. Cahn