Chemistry, physics and vacuum technique · 1832–1919
William Crookes
Crookes was an independent investigator who edited a chemical trade journal, ran his own laboratory and moved freely between analytical chemistry and the physics of rarefied gases. His evacuated tubes were the working tool that others used to study cathode rays, and his radiometer and spinthariscope became standard demonstrations. He also engaged publicly in spiritualist investigations, which his contemporaries regarded with varying degrees of embarrassment and which did not stop the Royal Society from electing him president.
Explore the supporting references at the foot of this article.
Contribution & context
In 1861, examining the selenium-bearing residue from a sulfuric acid plant with a spectroscope, he saw an unfamiliar green line and named the element thallium after the green shoot it resembled. He established its properties over the following years while disputing priority with Lamy, who had isolated the metal independently.
USGS — ThalliumUSGS — ThalliumRSC Periodic Table — ThalliumRSC Periodic Table — CadmiumLANL Periodic Table — Cadmium
Discoveries in context
Elements found by their colors ↗
Once a flame’s light could be spread into sharp lines and matched against a catalog, an element could be detected before anyone had a weighable sample of it.
Sources & further reading
- USGS — Thallium ↗United States Geological SurveyReference explanation · Source checked
- USGS — Thallium ↗United States Geological SurveyReference explanation · Source checked
- RSC Periodic Table — Thallium ↗Royal Society of ChemistryReference explanation · Source checked
- RSC Periodic Table — Cadmium ↗Royal Society of ChemistryReference explanation · Source checked
- LANL Periodic Table — Cadmium ↗Los Alamos National LaboratoryReference explanation · Source checked
Sources and further reading. What the review labels mean