Assertion: harpsichord's octave | /r/CapableOf | originate as an extension of keyboards
Facets:
Source sentences:
text: The 18th-century author Quirinus van Blankenburg suggested that the C/E short octave originated as an extension of keyboards that went down only to F; the addition of just one key (nominal E) and the reassignment of the F♯ and G♯ added three new notes to the bass range.