PLUCKER, JULIUS (]SO]-6S). A German mathematician and physicist, born at Elberfeld. After holding positions at the uni versities of Halle and Berlin he became pro fessor of mathematics at Bonn (1836). Plficker produced works of very great importance in the field of analytic geometry. In his Analy tisch-geometrische Entwickelungen (2 vols., 1828, 1831) he developed the dual relation between modern analysis and pure geometry. The System, dcr analytischen Geometric (1835) deals exten sively with the classification of cubic curves. His Theorie der algebraischen Curren (1839) contains the famous 'six equations' relating to the singularities of higher plane curves. (See CURVE.) This was followed by his System der Geometric des Raumes in never analytzscher Be handlungsweise (1846; 3d ed. 1852). From 1847 onward Pltieker devoted his attention to physics, and he became professor of this science at Bonn. He devoted his attention especially to the magnetic properties of gases and fluids, to the electric luminosity of rarefied space. and to the phenomena of the spectroscope and the Geissler tubes. In 1865 Plficker once more turned his at
tention to mathematics and invented what is now called line geometry. He died before he had finished the publication of a work on this subject. containing his theory of 'complexes' and 'congruences' (see CONGRUENCE ) . but it was com pleted by his pupil and assistant, Klein. under• the title Xeue Geometric des Raumes gegriindet ant die Betrachtung der geradcn Linie als Baum element ( 1868-69 ) . His scientific memoirs were published in the Proceedings of the Royal Society of Science at He was also a contributor to the Philosophical Transac tions of the Royal Society. Among the papers contributed are "On a New Geometry of Space" (1865. vol. 1551 : "On the Mag netic Induction of Crystals" (1858, vol. 148) ; "On the Spectra of Ignited Gases" ( ]S65. vol. 155). Consult: Clebseh. Zinn Gediichtnis an J. Plucker (G6ttingen. 1872) ; Dronke, Julius Pliicker (Bonn. 1871). His Gcsammelte Abhand Bingen have been published in two parts by the Royal Society of GiAtingen (Leipzig. 1895-96).