Aston, Francis William (1877–1945)
Francis Aston was a British physicist who was awarded the 1922 Nobel Prize in
Chemistry for his work on isotopes. Aston
developed the mass spectrograph (see mass
spectrometry) that separates isotopes, and he used it to identify 212
naturally occurring isotopes. His work led to the formulation of the whole-number
rule for isotopic weights.