Albert Johannsen

Background

Albert Johannsen was born on December 3, 1871, in Belle Plaine, Iowa, United States.

Education

Johannsen was educated at the universities of Illinois (Bachelor of Science, 1894), Utah (Bachelor of Arts, 1898), and Johns Hopkins (Ph.D., 1903).

Career

Johannsen worked for the Maryland Geological Survey in 1901-1903 and for the U.S. Geological Survey in 1903-1925, during which time he served as acting chief of the petrology section from 1907 to 1910.

In 1910 Johannsen went to the University of Chicago where he rose in eight years to the rank of full professor. Principally a petrographer, his early contributions were mainly improvements of the polarizing microscope and methods of optical analysis of minerals (1918). About this time Johannsen began work on a quantitative mineralogical classification of the igneous rocks primarily because of “errors introduced by loose usage of petrologic terms.” His classification is “strictly mineralogical, quantitative and modal” and used as its base the “double tetrahedron” with quartz, potassium feldspar, sodium feldspar, calcium feldspar, and the feldspathoids as end members. It is this classification that is used in his major scientific work, the four-volume Descriptive Petrography of the Igneous Rocks. It includes complete petrographic descriptions, chemical and modal analyses, and the historical background of virtually all known igneous rocks, as well as biographical sketches of the early petrologists responsible for identifying and studying many of those rocks.

Johannsen retired in 1937. The remaining twenty-five years of his life were spent in nonscientific pursuits, yet the two works produced during this period are indicative of his scientific approach. From his keen interest in the “dime and nickel novels” of the late nineteenth century came the history and biographies of the House of Beadle and Adams. His collection of the first editions of the works of Charles Dickens provided the source for a detailed examination of the plates in Dickens’ novels and the publication of Hablot Knight Browne (1815-1822): PhizIllustrations From the Novels of Charles Dickens.

Achievements

• Albert Johannsen went down in history as a noted geologist and mineralogist who contributed greatly to the development of petrology and petrography. He is probably best known for his quantitative mineralogical classification of the igneous rocks. Although Johannsen’s classification is not in use today, the information contained in this work serves as a standard reference in the field of petrography and as a monument to the thoroughness and meticulous attention to detail so characteristic of his scientific work.
  
  

Works

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  • Manual of petrographic methods 1918
  • Essentials for the Microscopical Determination of Rock-forming Minerals and Rocks, in Thin Sections 1922
  • The Fundamental Principles of Petrology 1916
  • The House of Beadle and Adams and Its Dime and Nickel Novels: The Authors and Their Novels, Volume 2, Part 4 1950
  • A key for the determination of rock-forming minerals in thin sections 1908

Personality

Johannsen was noted for his unwavering eye for detail, a trait revealed throughout his entire career.

References

• Dictionary of Scientific Biography, Volume 7
  1973