Lord Rayleigh (1842-1919) and William Ramsay (1852-1916) discover argon by spectroscopically analyzing the gas left over after nitrogen and oxygen are removed from air
Editors. "Argon discovered". The Literary Encyclopedia. First published 01 May 2009; last revised 30 November -1.
[http://www.litencyc.com/php/stopics.php?rec=true&UID=6373, accessed 27 April 2015.]