Assertion: trombone | /r/HasProperty | improved in 19th century
Facets:
value: further
type: DEGREE
Source sentences:
text: The trombone was further improved in the 19th century with the addition of "stockings" at the end of the inner slide to reduce friction, the development of the water key to expel condensation from the horn, and the occasional addition of a valve that, intentionally, only was to be set on or off but later was to become the regular F-valve.