Assertion: fountain pen's reservoir | /r/HasProperty | met by the influx of air
Facets:
Source sentences:
text: He explains that the basic mechanism involves a careful balance between ink leaving the pen and air entering: "The downward flow of the ink by gravity and through the action of capillary attraction in the act of writing causes it to pass through [a] groove, and tends to create a vacuum within the reservoir, which is met by the influx of air passing upward through the groove.