Assertion: mortar | /r/ObjectUse | used as the launching mechanism
Facets:
value: for test-firing aerial bombs
type: PURPOSE
value: originally
type: MANNER
value: at aberdeen proving ground
type: LOCATION
Source sentences:
text: The mortar was originally used as the launching mechanism for test-firing aerial bombs at Aberdeen Proving Ground (during the war, bombs became larger and larger, necessitating the construction of such a large-calibre gun).