1913 - Science

Science

Physicist William H. Bragg uses an ionization chamber in January to detect reflected rays (see von Laue, 1912); by March he has constructed the first X-ray spectrometer and will use it to investigate the spectral distribution of the X-rays, relations between wave length and Planck's constant, etc.

A paper published by English physicist Henry (Gwyn Jeffreys) Moseley, 25, reports that the frequencies of corresponding lines in X-ray spectra are proportional to the squares of whole numbers that are equal to the atomic number plus a constant ("Moseley's Law"). Moseley has conducted a series of experiments in Ernest Rutherford's laboratory at the University of Manchester (see 1914).

A new model of the atom devised by Danish physicist Niels Bohr, 28, violates classical electromagnetic theory but successfully accounts for the spectrum of hydrogen (see Balmer, 1885). Applying Max Planck's quantum theory of 1900 to Ernest Rutherford's nuclear atom of 1911, Bohr proposes a planetary model of the atom in which electrons orbit the nucleus and actually jump between orbits as the atom absorbs or emits energy (see 1939; Schrödinger, 1926).

The Concept of a Riemann Surface (Die Idee der Riemannschen Fläche) by German mathematician Hermann Weyl, 27, pioneers a new branch of mathematics by uniting function theory and geometry, thus opening a synoptic view of analysis, geometry, and topology. Weyl has studied at the University of Göttingen under David Hilbert and is appointed to a professorship at Zürich's Technische Hochschule, where his colleagues include Albert Einstein.

Michigan-born Harvard mathematician George D. (David) Birkhoff, 29, gives proof of a geometric theorem in topology (the study of surfaces and spaces) first proposed by the late Jules-Henri Poincaré.

Illinois-born geneticist Alfred H. (Henry) Sturtevant, 21, develops a technique for mapping the location of the specific genes in the chromosomes of the fruit fly Drosophila (see Morgan, 1909; Lewis, 1978).

Zoologist Adam Sedgwick dies at London February 27 at age 58; naturalist Alfred Russel Wallace at Broadstone, Sussex, November 7 at age 90.