A vent is formed in the flask in such manner as to prevent accidental spillage of liquid therefrom while also permitting entrance of air into the flask when {HEAD ~ negative internal pressure} is applied during {TAIL ~ removal} of liquid therefrom 
is applied during
A vent is formed in the flask in such manner as to prevent accidental spillage of liquid therefrom while also permitting entrance of air into the flask when { HEAD ~ negative internal pressure } is applied during { TAIL ~ removal } of liquid therefrom
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH