Isolating the element thulium was a truly laborious process that took many years.
Charles James had to carry out 15,000 recrystallisations to prepare his sample when he was wanting to determine the atomic weight of thulium, says Professor Allan Blackman from the Auckland University of Technology, in episode 86 of Elemental.
The Elemental podcast is celebrating 150 years since the periodic table was first published by Russian chemist Dmitri Mendeleev.
Find out more about events during the United Nation’s International Year of the Periodic Table.
Professor Allan Blackman is at Auckland University of Technology.