Assertion: gas balloon | /r/ObjectUse | used for observation purposes
Facets:
value: in world war
type: TEMPORAL
value: to very limited extent
type: OTHER
value: by aviators
type: OTHER
Source sentences:
text: Tethered manned gas balloons were used for observation purposes in the Napoleonic Wars (to very limited extent), in the American Civil War (flown by Thaddeus Lowe) and in World War I by aviators wearing parachutes.