Wilhelm Ferdinand Fuhrmann (28 February 1833 – 11 June 1904) was a German mathematician. The

Fuhrmann circle __notoc__ In geometry, the Fuhrmann circle of a triangle, named after the German Wilhelm Fuhrmann (1833–1904), is the circle that has as a diameter the line segment between the orthocenter H and the Nagel point N. This circle is identical with ...

and the Fuhrmann triangle are named after him.Roger A. Johnson: ''Advanced Euclidean Geometry''. Dover 2007, , pp. 228–229, 300 (originally published 1929 with Houghton Mifflin Company (Boston) as ''Modern Geometry'').

Biography

Fuhrmann was born on 28 February 1833 in

Burg bei Magdeburg Burg (also known as Burg bei Magdeburg to distinguish from other places with the same name) is a town of about 22,400 inhabitants on the Elbe–Havel Canal in northeastern Germany, northeast of Magdeburg. It is the capital of the Jerichower Land ...

. Fuhrmann had shortly worked as sailor before he returned to school and attended the Altstadt Gymnasium in Königsberg, where his teachers noticed his interest and talent in mathematics and geography. He graduated in 1853 and went on to study mathematics and physics at the

University of Königsberg The University of Königsberg (german: Albertus-Universität Königsberg) was the university of Königsberg in East Prussia. It was founded in 1544 as the world's second Protestant academy (after the University of Marburg) by Duke Albert of Prussi ...

. One of his peers later remembered him as the most talented and diligent student of his class. Fuhrmann however despite his talent did not pursue a career at the university, instead he became a math and science teacher at the Burgschule in Königsberg after his graduation. He joined the school in 1860 and remained there until his death in 1904.L. Saalschütz: "Zur Erinnerung an Wilhelm Fuhrmann". In: ''Jahresbericht der Deutschen Mathematiker-Vereinigung'', Volume 14, 1905, pp. 56–60.
online copy
Fuhrmann authored several books and a number of papers on different mathematical subjects. Today he is best remembered for his interest in and contribution to elementary geometry. With ''Synthetische Beweise planimetrischer Sätze'' he wrote an influential book on the subject and in 1890 he published an article entitled ''Sur un nouveau cercle associé à un triangle'' in the Belgian math journal Mathesis. In this article Fuhrmann described the circle and the triangle that now carry his name.Jan Vonk, J. Chris Fisher
"Translation of Fuhrmann’s “Sur un nouveau cercle associe´ a un triangle”
In: ''Forum Geometricorum'', Volume 11 (2011), pp. 13–26

Publications

Papers

* ''Transformationen der Theta-Funktionen'' (1864) * ''Einige Untersuchungen über die Abhängigkeit geometrischer Gebilde'' (1869) * ''Einige Anmerkungen der projektiven Eigenschaften der Figuren'' (1875) * ''Aufgaben über Kegelschnitte'' (1879) * ''Aufgaben aus der niederen Analysis'' (1886) * ''Der Brocardsche Winkel'' (1889) * "Sur un nouveau cercle associé à un triangle". In: ''Mathesis'', 1890
English translation
* ''Sätze und Aufgaben aus der sphärischen Trigonometrie'' (1894) * ''Beiträge zur Transformation algebraisch-trigonometrischer Figuren Teil 1'' (1898) * ''Beiträge zur Transformation algebraisch-trigonometrischer Figuren Teil 2'' (1899) * ''Kollineare und orthologische Dreiecke'' (1902) * ''Aufgaben aus der analytischen Geometrie'' (1904, post mortem)

Books

* ''Synthetische Beweise planimetrischer Sätze''. Berlin: L. Simion, 1890. Heute: Wentworth Press, 2018,
online copy
in the

Internet Archive The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, ...

) * ''Kollineare und orthologische Dreiecke''. Königsberg: Hartung, 1902. * ''Wegweiser in der Arithmetik, Algebra und niedern Analysis''. Leipzig: Teubner, 1886.

References

{{DEFAULTSORT:Fuhrmann, Wilhelm Ferdinand 19th-century German mathematicians 1833 births 1904 deaths Mathematicians from the Kingdom of Prussia Mathematicians from the German Empire