Assertion: hydrogen | /r/ObjectUse | used as lifting agent
Facets:
value: originally
type: OTHER
value: in balloons
type: LOCATION
value: in zeppelins
type: LOCATION
Source sentences:
text: It was originally used as a lifting agent in balloons and zeppelins because it was so light, but the explosive nature of the gas led to the proposal of helium as a more stable and safe replacement.