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August Herman Pfund (December 28, 1879 – January 4, 1949) was an American-born physicist, spectroscopist, and inventor.

August Herman Pfund
Born(1879-12-28)December 28, 1879
DiedJanuary 4, 1949(1949-01-04) (aged 69)
Alma mater
Known for
Scientific career
InstitutionsJohns Hopkins University
Doctoral advisorRobert W. Wood


Early lifeEdit

Pfund was born in Madison, Wisconsin and attended Wisconsin public schools until his entry into the University of Wisconsin–Madison, where he earned a B.S. degree in physics and studied under Robert W. Wood.


Both Wood and Pfund left Wisconsin for Johns Hopkins University in 1903. From 1903 to 1905 Pfund was a Carnegie research assistant and continued to work under Wood. In 1906 Pfund earned his Ph.D. in physics and was a Johnston scholar from 1907 to 1909. He remained at Hopkins for the remainder of his career, eventually becoming a full professor and later chair of the physics department. From 1943 to 1944 Pfund served as the president of the Optical Society of America.

Within the hydrogen spectral series Pfund discovered the fifth series, where an electron jumps up from or drops down to the fifth fundamental level. This Series is known as the "Pfund series". He also invented the Pfund telescope, which is a method for achieving a fixed telescope focal point regardless of where the telescope line of sight is positioned, and the Pfund sky compass,[1] which arose from Pfund's studies of the polarization of scattered light from the sky in 1944, and which greatly helped transpolar flights by allowing the determination of the Sun's direction in twilight.[2] Pfund is also noted for his work into the area of infrared gas analysis.

See alsoEdit


  1. ^ Moody, Lieutenant Commander Alton B., "The Pfund Sky Compass", Navigation, Journal of The Institute of Navigation, Vol. 2, No. 7, 1950.
  2. ^ John Howard, "Presidents of the Late 1940s", Optics and Photonics News, June 2010.

Further readingEdit

  • Dr. John Andraos, Named Concepts in Chemistry (L-Z), York University, 2001
  • Pelletier, Paul A. (ed.), Prominent Scientists: An index to collective biographies, 2nd ed., Neal-Schuman Publishing, Inc.: New York, 1985 (citations only)
  • Cattell, J.M.; Cattell, J. American Men of Science, 6th ed., The Science Press: New York, 1938
  • Journal of the Optical Society of America, 39:4 (April, 1949) 325. Obit.

External linksEdit