Francis William Aston

Francis William Aston
Born (1877-09-01)1 September 1877
Harborne, Birmingham, England, U.K.
Died 20 November 1945(1945-11-20) (aged 68)
Cambridge, England, U.K.
Citizenship British
Nationality English
Fields Chemistry, physics
Institutions Trinity College, Cambridge
Alma mater Mason College
Trinity College, Cambridge
Academic advisors J. J. Thomson
Known for Mass spectrograph
Whole Number Rule
Notable awards Nobel Prize for Chemistry (1922)
Hughes Medal (1922)
Royal Medal (1938)
Duddell Medal and Prize (1944)
External video
Michael A. Grayson, Discovery of Isotopes of Elements (Part II: Francis William Aston), Profiles in Chemistry, Chemical Heritage Foundation

Francis William Aston FRS[1] (1 September 1877 – 20 November 1945) was an English chemist and physicist who won the 1922 Nobel Prize in Chemistry for his discovery, by means of his mass spectrograph, of isotopes, in a large number of non-radioactive elements, and for his enunciation of the whole number rule.[2][3] He was a fellow of the Royal Society[1] and Fellow of Trinity College, Cambridge.[4]

Early life

Francis Aston was born in Harborne, now part of Birmingham, on 1 September 1877.[5] He was the third child and second son of William Aston and Fanny Charlotte Hollis. He was educated at the Harborne Vicarage School and later Malvern College in Worcestershire where he was a boarder. In 1893 Francis William Aston began his university studies at Mason College (which later became Mason University College and then the University of Birmingham) where he was taught physics by John Henry Poynting and chemistry by Frankland and Tilden. From 1896 on he conducted additional research on organic chemistry in a private laboratory at his father’s house. In 1898 he started as a student of Frankland financed by a Forster Scholarship; his work concerned optical properties of tartaric acid compounds. He started to work on fermentation chemistry at the school of brewing in Birmingham and was employed by W. Butler & Co. Brewery in 1900. This period of employment ended in 1903 when he returned to the University of Birmingham under Poynting as an Associate.


With a scholarship from the University of Birmingham he pursued research in physics following the discovery of X-rays and radioactivity in the mid-1890s. Aston studied the current through a gas-filled tube. The research, conducted with self-made discharge tubes, led him to investigate the volume of the Aston dark space.[6][7][8]

After the death of his father, and a trip around the world in 1908, he was appointed lecturer at the University of Birmingham in 1909 but moved to the Cavendish Laboratory in Cambridge on the invitation of J. J. Thomson in 1910.

Birmingham University awarded him a BSc in Applied/Pure Science in 1910 and a DSc in Applied/Pure Science in 1914.[9]

Joseph John Thomson revealed the nature of the cathode ray and then discovered the electron and he was now doing research on the positively charged "Kanalstrahlen" discovered by Eugen Goldstein in 1886. The method of deflecting particles in the "Kanalstrahlen" by magnetic fields was discovered by Wilhelm Wien in 1908; combining magnetic and electric fields allowed the separation of different ions by their ratio of charge and mass. Ions of a particular charge/mass ratio would leave a characteristic parabolic trace on a photographic plate, demonstrating for the first time that atoms of a single element could have different masses. The first sector field mass spectrometer was the result of these experiments.

It was speculations about isotopy that directly gave rise to the building of a mass spectrometer capable of separating the isotopes of the chemical elements. Aston initially worked on the identification of isotopes of the element neon and later chlorine and mercury. First World War stalled and delayed his research on providing experimental proof for the existence of isotopes by mass spectroscopy and during the war Aston worked at the Royal Airforce Establishment in Farnborough as a Technical Assistant working on aeronautical coatings.

After the war he returned to research at the Cavendish Laboratory in Cambridge, and completed building his first mass spectrograph that he reported on in 1919. Subsequent improvements in the instrument led to the development of a second and third instrument of improved mass resolving power and mass accuracy. These instruments employing electromagnetic focusing allowed him to identify 212 naturally occurring isotopes. In 1921, Aston became a member of the International Committee on Atomic Weights,[10] a fellow of the Royal Society[1] and received the Nobel Prize in Chemistry the following year.

His work on isotopes also led to his formulation of the whole number rule which states that "the mass of the oxygen isotope being defined [as 16], all the other isotopes have masses that are very nearly whole numbers," a rule that was used extensively in the development of nuclear energy. The exact mass of many isotopes was measured leading to the result that hydrogen has a 1% higher mass than expected by the average mass of the other elements. Aston speculated about the subatomic energy and the use of it in 1936.

Isotopes[11] and Mass-spectra and Isotopes[12] are his most well-known books.

Private life

In his private life he was a sportsman, cross-country skiing and skating in winter time, during his regular visits to Switzerland and Norway; deprived of these winter sports during the First World War he started climbing. Between the ages of 20 and 25 he spent a large part of his spare time cycling. With the invention of motorized vehicles he constructed a combustion engine of his own in 1902 and participated in the Gordon Bennett auto race in Ireland in 1903. Not content with these sports he also engaged in swimming, golf, especially with Rutherford and other colleagues in Cambridge,[13] tennis, winning some prizes at open tournaments in England Wales and Ireland and learning surfing in Honolulu in 1909. Coming from a musical family, he was capable of playing the piano, violin and cello at a level such that he regularly played in concerts at Cambridge. He visited many places around the globe on extensive travel tours starting from 1908 when he visited and ending with a trip to Australia and New Zealand in 1938–1939.[1][14]

Aston was a skilled photographer and interested in astronomy. He joined several expeditions to study solar eclipses in Benkoeben in 1925, Sumatra in 1932, Magog in Canada on August 31, 1932 and Kamishri[?] in Japan. He also planned to attend expeditions to South Africa in 1940 and Brazil in 1945 in later life. He never married.


Aston died in Cambridge on 20 November 1945. He was 68 years old.[4]


The lunar crater Aston was named in his honor.

The British Mass Spectrometry Society awards the Aston Medal in his honor.


  1. 1 2 3 4 Hevesy, G. (1948). "Francis William Aston. 1877-1945". Obituary Notices of Fellows of the Royal Society. 5 (16): 634–626. doi:10.1098/rsbm.1948.0002. JSTOR 768761.
  2. "The Nobel Prize in Chemistry 1922". Nobel Foundation. Retrieved 2008-04-14.
  3. Squires, Gordon (1998). "Francis Aston and the mass spectrograph". Dalton Transactions (23): 3893–3900. doi:10.1039/a804629h. Retrieved 2007-12-06.
  4. 1 2 "Dr. F.W. Aston Dies. Winner of the Nobel Prize in Chemistry in 1922. Noted for His Work With Isotopes. In Tour of This Country 23 Years Ago, He Foresaw the Releasing of New Energy. Developed Isotopes. Headed Atom Committee. Lectured in This Country". New York Times. November 22, 1945. Retrieved 2010-08-06. The death of Dr. Francis William Aston, fellow of the Royal Society and Fellow of Trinity College, Cambridge, was announced today. He was 68 years old.
  5. Plaque #1616 on Open Plaques.
  6. Francis William Aston (1907). "Experiments on a New Cathode Dark Space in Helium and Hydrogen". Proceedings of the Royal Society A. 80 (535): 45–49. Bibcode:1907RSPSA..80...45A. doi:10.1098/rspa.1907.0072. JSTOR 92589.
  7. Francis William Aston (1907). "Experiments on the Length of the Cathode Dark Space with Varying Current Densities and Pressures in Different Gases". Proceedings of the Royal Society A. 79 (528): 80–95. Bibcode:1907RSPSA..79...80A. doi:10.1098/rspa.1907.0016. JSTOR 92573.
  8. Francis William Aston (1911). "The Distribution of Electric Force in the Crookes Dark Space". Proceedings of the Royal Society A. 84 (573): 526–535. Bibcode:1911RSPSA..84..526A. doi:10.1098/rspa.1911.0005. JSTOR 93257.
  10. F.W. Aston; et al. (1923). "Report of the International Committee on Chemical Elements: 1923". J. Am. Chem. Soc. 45 (4): 867–874. doi:10.1021/ja01657a001.
  11. Aston, Francis William (1922). Isotopes. London: E. Arnold. p. 152.
  12. Aston, Francis William (1933). Mass-Spectra and Isotopes. London: Edward Arnold.
  13. KM Downard (2007). "Cavendish's Crocodile and Dark Horse – The Lives of Rutherford and Aston in Parallel". Mass Spectrometry Reviews. 26 (5): 713–723. doi:10.1002/mas.20145. PMID 17546675.
  14. KM Downard (2007). "Francis William Aston – the man behind the mass spectrograph". European Journal of Mass Spectrometry. 13 (3): 177–190. doi:10.1255/ejms.878. PMID 17881785.

External links

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