MAGNUS, LUDWIG IMMANUEL:
German mathematician; born in Berlin March 15, 1790; died there Sept. 25, 1861; cousin of Heinrich Gustav Magnus. His father died when he was young; and his mother induced him to enter his uncle's bank; after business hours he studied Euclid. In the Napoleonic wars he was a volunteer in the artillery, being soon promoted to the rank of gunner and serving from 1813 to 1815. On the conclusion of peace he again took up the business of banking in Berlin; in his leisure hours studying higher mathematics, and teaching that subject in the academy founded in 1816 by a brother of the sculptor Cauer. On the removal of the academy to Charlottenburg (1826) Magnus continued to be one of its regular staff of teachers; and he held that position until 1834, when Cauer died. Magnus then abandoned teaching, and spent the next nine years as head revenue officer in the recently founded Berliner Kassenverein, retiring in 1843 on a competency. Hard work had, however, broken his health, and he did nothing more for mathematics. During the latter part of his life he was an invalid, suffering from a disease of the eyes.
By 1834 Magnus' reputation as a mathematician had become established, and the University of Bonn conferred upon him the honorary degree of doctor. Magnus' mathematical writings appeared in Gergonne's "Annales des Mathématiques," vols. xi. and xvi. (1820-25); in Crelle's "Journal," vols. v., vii., viii., and ix. (1830-32); in the third part (1833) of Meier Hirsch's "Sammlung Geometrischer Aufgaben"; and in "Sammlung von Aufgaben und Lehrsätzen aus der Analytischen Geometrie des Raumes" (published in 1837, but written long before).
- Allg. Deutsche Biographie, xx. 91-92, Leipsic, 1884;
- Poggendorff, Biog.-Literarisch Handwörterb. Leipsic, 1863, s.v.