Cavendish Laboratory : Aston's third mass spectrograph

Cavendish Laboratory

<p style='text-align: justify;'>Photograph of Aston's second mass spectrograph showing the large permanent magnet produced by the Pye Company of Cambridge. Aston devoted his scientific career to the perfection of the mass spectrograph. Following his pioneering discovery of non-radioactive isotopes with JJ Thomson in 1912, he developed a series of mass spectrographs. Among the many accurate mass and isotope determinations, were those of the complete set of rare earth elements, thanks to the gift of a presentation set of these by Carl Auer von Welsbach, who is credited with the discovery of three rare earth metals: lutetium, praseodymium, and neodymium.</p>