A chemist who led the chemistry department at University College London from 1887 to 1913. His isolation of argon followed John William Strutt, 3rd Baron Rayleigh's observation that atmospheric nitrogen had greater density than chemically prepared nitrogen.[ref]
https://www.ucl.ac.uk/mathematical-physical-sciences/chemistry/about-us/history-department. History of the Department, Ramsay and the nobel gases: chemistry professorship, headship dates and argon isolation
Portrait of William Ramsay
. Portrait reproduced from The World's Work; photographer unidentified. Wikimedia Commons file description and provenance. Source.