Assertion: clavichord's key | /r/HasProperty | extended to the back of the case
Facets:
value: beneath the sound-board
type: LOCATION
Source sentences:
text: The keys were in front, and extended beneath the sound-board to the back of the case, each being balanced upon a wire pin, and prevented from rattling against its neighbour by a small piece of whalebone projecting from the key and sheathed in a groove behind (Fig. 2).