John David Main Smith

John David Main Smith was a British chemist.

Mostly cited by John D. Main Smith. Main Smith is the last name, which is why he is also quoted Main-Smith.

biography

He graduated from London with a bachelor's degree and received his PhD in chemistry from the University of Birmingham, where he was a research assistant with Gilbert Thomas Morgan . In 1924 he worked at the University of Birmingham .

As his biographer Eric Scerri wrote, Smith is still largely unknown today, but in 1924/25 he made interesting, if little noticed, contributions to atomic physics in Bohr's model. This was due to the fact that he published in the journal Chemistry & Industry, which physicists did not read, but it also received little response from chemists. His findings were also found again independently by Edmund Stoner (then a student at Cambridge), whose contribution was temporarily forgotten in the history of science, but at that time had an influence on Bohr, Arnold Sommerfeld and Wolfgang Pauli (principle of exclusion), for example . From the arrangement of the elements in the periodic table, Smith concluded that Niels Bohr's symmetrical image of the electron shells could not be correct. Instead, each Smith shell began with a subshell with 2 electrons (later called s orbitals) and the second shell had subshells with 2, 2 and 4 electrons instead of two with 4 electrons each, as Bohr assumed. Each subgroup of a shell had a maximum of electrons (with angular momentum). He published a book on atomic physics and chemistry and in 1924 corresponded with Arnold Sommerfeld about it. ${\displaystyle 2(2l+1)}$ ${\displaystyle l}$

He also knew the effect of the inert electron pair .

Elsewhere (in a 1927 publication) he was wrong, so he believed that in the 7th period, of which uranium, thorium, actinium, protactinium and radium were known, there were only 18 and not 32 elements as in the 6th period. Group (that only changed with Glenn Seaborg in the 1940s).

For Scerri, Main Smith is an example of the important role small, lesser-known scientists play in the development of science alongside that of the well-known luminaries.

Later he was a chemist ( Principal Scientific Officer ) at the Royal Aircraft Establishment in Farnborough and invented a method to remove fog and smog from airfields during World War II (FIDO, Fog Investigation and Dispersal Operation). For this purpose, gas was ignited along the runway, which leaked from small holes in pipes.

He was also an examiner at the University of London. Contributions to the Encyclopaedia Britannica come from him.

Fonts

• Chemistry and Atomic Structure , Ernest Benn, London, 1924, Archives
• Periodic classification and atomic structures of the elements from "Chemistry and atomic structure." Benn, London, 1925.
• together with Aeronautical Research Council (Great Britain): Chemical solids as diffusible coating films for visual indications of boundary-layer transition in air and water. HMSO, London, 1954.

literature

• Eric Scerri: A Tale of Seven Scientists, and a New Philosophy of Science, Oxford University Press, New York, 2016, p. 103.

Web links

• Eric Scerri: Who Was John David Main Smith? , Oxford University Blog, March 12, 2016.

Individual evidence

1. ^ Salvatore Califano: Pathways to Modern Chemical Physics. Springer Science & Business Media, 2012, ISBN 978-3-642-28180-8 , p. 128.
2. ^ John David Main Smith: Chemistry and Atomic Structure . Ernest Benn, London, 1924, Archives .
3. ↑ However, there is almost no biographical information in his book A tale of seven scientist . But he added a photo.
4. ^ Richard Rennie: A Dictionary of Chemistry. Oxford University Press, 2016, ISBN 978-0-191-05943-8 , p. 344.
5. ^ Richard Rennie: A Dictionary of Physics. Oxford University Press, 2019, ISBN 978-0-192-55461-1 , p. 646.
6. ^ Sommerfeld Correspondence, LMU Munich .
7. ^ Espacenet : Improvements in or relating to the dispersal of fog . Patent GB595907 (A), dated December 23, 1947.
8. ^ Entry among the authors of the Encyclopaedia Britannica from 1951.