Assertion: fountain pen's reservoir | /r/HasProperty | squeezed flat
Facets:
value: by an internal plate
type: CAUSE
Source sentences:
text: By 1915, most pens had switched to self-filling soft and flexible rubber sacs -- to refill these pens, the reservoirs were squeezed flat by an internal plate, then the pen's nib was inserted into a bottle of ink and the pressure on the internal plate was released so the ink sac would fill up, drawing in a fresh supply of ink.