KLEIN, FELIX (I849-1925), German mathematician, was born at Dusseldorf on April 25, 1849, and after studying at the universities of Bonn, Gottingen and Berlin was appointed pro fessor of mathematics at the University of Erlangen (1872-75). He later took up similar professorships at the Munich technical college (1875-8o), and at the universities of Leipzig (188o-86) and Gottingen (1886-1913), and finally became Professor Emeri tus at the latter university. He died at Giittingen on June 22, 1925.
Klein wanted to specialize in the application of mathematics and mechanics to physics, but was obliged to modify his plans owing to the breakdown of his health on two occasions. He limited himself to lectures and to the large number of books which he published. Most of these books were notes of lectures taken by Klein's students, revised and supervised by him. To further his idea of linking up mathematics with physics he founded the Encyklopddie for mathematics in 1895, he formed a committee from the German academies to accept responsibility for it and obtained contributors from many countries. Klein was the editor of the Mathematische Annalen from 1872. Klein's researches in mathematics were chiefly on geometry and the theory of functions, he supervised the collection and publication of his papers in three volumes (1921-23) and added an account of his mathematical development with many personal references. His well-known
treatise on the teaching of mathematics in Germany appeared in 1909. Klein was a member of many learned societies and was awarded the Copley Medal of the Royal Society in 1912. He travelled a good deal and lectured both in England and in America.