Assertion: thorium | /r/CapableOf | come into extensive demand
Facets:
value: in the 1880s
type: TEMPORAL
Source sentences:
text: After the development of the incandescent gas mantle by Carl Auer, Baron von Welsbach, in the 1880s, thorium came into extensive demand and use, but, when electric power became generally available after 1920, worldwide utilization of thorium gas mantles sharply declined.