1940 - Science

Science

A Columbia University research team isolates the rare isotope uranium 235 from its more abundant chemical twin uranium-238 by means of a gaseous diffusion process developed by J. R. Dunning and his colleagues (see 1939; Dempster, 1935). Dunning shows that the isotope is the form of uranium that readily undergoes fission into two atoms of nearly equal size, thus releasing prodigious amounts of energy (the gaseous diffusion process will be the major source of uranium 235 used for fueling atomic reactors).

German-born British physicist Rudolph E. (Ernst) Peierls, 33, and his University of Birmingham colleague Otto Frisch issue a three-page memorandum theorizing (correctly) that a highly explosive but compact bomb could be made from small amounts of the isotope uranium 235 separated from uranium 238. Scientists have heretofore believed that several tons of uranium would be needed for an effective bomb.

University of California, Berkeley, physicist Edwin M. (Mattison) McMillan, 32, and his Tacoma, Wash.-born colleague Philip (Hauge) Abelson, 26, at the Lawrence Radiation Laboratory discover the first transuranium chemical element. It is a radioactive element heavier than uranium, they classify it as radioactive element 93 (it will later be called neptunium), and they suggest the existence of another, still heavier, transuranium isotope with a mass of 239 that will be called plutonium (see Seaborg, Segrè, 1941).

The world's first electron microscope is demonstrated April 1 at the RCA Laboratories at Camden, N.J. RCA engineers supervised by Russian-born researcher Vladimir (Kosma) Zworykin, 50, have developed the microscope, which is 10 feet high, weighs 700 pounds, can magnify up to 100,000 diameters, and will permit scientific studies impossible with conventional microscopes.

German-born U.S. biologist Max Delbrück, 34, Italian-born U.S. biologist Salvador Edward Luria, 28, and Michigan-born chemist A. D. (Alfred Day) Hershey, 31, advance knowledge of molecular biology, making basic discoveries in bacterial and viral reproduction and mutation involving nucleic acid in cells (see Watson, Crick, 1953).

The Lascaux caves discovered by French schoolboy Jacques Marsal near Périgueux have wall drawings that show how man lived at least 16,000 years ago.

Archaeologist Wilhelm Dörpfeld dies on the Greek island of Leukas April 25 at age 86, having excavated the Mycenaean palace at Tiryns (later Tirins) and continued the excavations of ancent Troy by the late Heinrich Schliemann in Turkey; anatomist-geologist Eugène Dubois of Java Man fame dies at de Bedlaer in the Netherlands December 16 at age 82.

The carbon-14 isotope discovered by Canadian-born U.S. biochemist Martin D. (David) Kamen, 27, will be a basic tool in biochemical and archaeological research (see Libby, 1947).

Nobel industrial chemist Carl Bosch dies at Heidelberg April 26 at age 65; Nobel biochemist Sir Arthur Harden of a progressive nervous disease at Bourne End, Buckinghamshire, June 17 at age 74; Nobel physicist Sir Joseph John Thomson at Cambridge, Cambridgeshire, August 30 at age 83; biochemist Phoebus A. T. Levene at New York September 6 at age 71; physicist Heinrich Kayser at Bonn October 14 at age 87.