1897 - Science

Science

"Commentary on Numbers" ("Zahlbericht") by German mathematician David Hilbert, 35, at the University of Göttingen consolidates what is known on the subject of invariants (entities that remain unchanged during geometric alterations such as dilation, reflection, and rotation). Hilbert has earlier proved that all invariants can be expressed in terms of a finite number (see 1900).

The atom that ancient Greeks believed to be indivisible turns out to have a nucleus orbited by one or more electrons (see Democritus, 330 B.C.; Stoney, 1874; Perrin, 1895). Modifying the idea formulated by John Dalton in 1803 and tabularized by Dmitri Mendeléev in 1870, English physicist Joseph John Thomson, 41, shows that the structure of each element is characterized not merely by a different atomic weight but also by an atomic number, and shows that this number is the number of electrons orbiting the nuclei of the element's atoms (see Wien, 1898; Bragg, 1904; Rutherford, 1911; neutron, 1932). Thomson's finding has no known practical application, but it will lead within 20 years to the start of an electronics industry that will change many people's lives (see 1904). Thomson's Irish-born research assistant John S. E. (Sealy Edward) Townsend, 29, devises a falling-drop procedure for measuring the unit electrical charge (e) in the electrical conduction of gases, using saturated clouds of water (see Millikan, 1917; Townsend, 1901).

Physicist Galileo Ferraris dies at Turin February 7 at age 49; botanist Julius von Sachs at Würzburg May 29 at age 64; analytical chemist Carl Remigius Fresenius at Wiesbaden June 11 at age 78.