British mathematician, astronomer, geophysicist, and philosopher Sir Harold Jeffreys (1891-1989) was one of the great original applied-mathematical thinkers of the 20th century. He is noted for his wide variety of scientific contributions.

Harold Jeffreys was born on April 22, 1891, in Durham, England. He graduated from Durham University and then carried out research in chemistry and photography. He won major prizes at the University of Cambridge, from which he graduated in 1917, in mathematics, astronomy, and geophysics. At Cambridge he was a lecturer in mathematics, reader in geophysics, and Plumian professor of astronomy and experimental philosophy from 1946 to his retirement in 1958. In 1940 he married Bertha Swirles, a talented mathematician and a fellow of Girton College, Cambridge.

Scientific Contributions

The contributions for which Jeffreys is noted cover a wide range of fields. Much of his interest centered on the solar system and the theory of geophysics, fields in which progress demands the...