Francis Aston

Francis William Aston was born in September 1877 at Harborne, Birmingham, England, the third of seven children, and studied chemistry and physics at Mason College, Birmingham. After working for three years as a chemist in a brewery he turned to gas discharge in evacuated tubes, and in 1909 he joined Sir J. J. Thomson at the Cavendish Laboratory in Cambridge, where he obtained definite evidence for two isotopes of neon. Returning to the Cavendish Laboratory in 1919, he quickly succeeded in separating them with his invention of the mass spectrograph, an apparatus in which electromagnetic focusing exploits the slight differences in mass of the isotopes. With it he discovered no fewer than 212 naturally occurring isotopes and formulated the Whole Number Rule. He was made a Fellow of the Royal Society in 1921 and received the Nobel Prize in Chemistry in 1922.