<p style='text-align: justify;'>Colour photograph of Aston's 3rd (1937) mass spectrograph. Aston devoted his scientific career to the perfection of the mass spectrograph. Following his pioneering discovery of isotopes with Thomson in 1912, he developed a series of mass spectrographs, the third version shown here of 1937 having mass resolution approaching one part in 100,000.</p>