DEBYE, P. [PETER JOSEPH WILLIAM DEBYE].

Näherungsformeln für die Zylinderfunktionen für große Werte des Arguments und unbeschränkt veränderliche Werte des Index.

Leipzig, B.G. Teubner, 1909. 8vo. Original printed wrappers, no backstrip and a small nick to front wrapper. In "Mathematische Annalen. Begründet durch Rudolf Friedrich Alfred Clebsch. 67 Band. 4. Heft." Entire issue offered. Internally very fine and clean. [Debye:] Pp. 535-58. [Entire issue: Pp. 433-575].

First printing of Debye's early paper on the method of the steepest descent. Debye used it to estimate Bessel functions.
In mathematics, the method of steepest descent is an extension of Laplace's method for approximating an integral, where one deforms a contour integral in the complex plane to pass near a stationary point in roughly the direction of steepest descent or stationary phase.

"Debye was not only a brilliant and original scientist but also a wise and shrewd man of the world. In the performance of administrative duties in Berlin, he had to spend a great deal of time dealing with Nazi bureaucrats. He had retained his Dutch citizenship when he came to Berlin, having been told by the minister of education that he would not be required to become a German citizen. However, not long after World War II broke out, he was informed that he could not enter his laboratory if he did not become a German citizen. He refused to do so and soon succeeded in getting to the United States, where he became a citizen in 1946. He had lectured many times in the United States and had declined offers of professorships at many leading universities; but he now gave the Baker Lectures at Cornell University and was appointed professor of chemistry and head of the chemistry department there, positions which he held from 1940 to 1950, when he became professor emeritus. He continued active in research and consultation until the end of his life. The first ten years at Ithaca produced the work on light scattering, his last great contribution. Debye's many achievements were recognized by his election to membership in some twenty-two academies throughout the world and the award of twelve medals and eighteen honorary degrees." (DSB).

The issue also contains:
Klein, Felix. Über Selbstspannungen ebener Diagramme. Pp. 433-444.

Order-nr.: 44527