Dumb-vent
A vent from a hollow core led to some distance by means of an underground flue, where there will be no possibility of sparks igniting the gas and causing an explosion. See VENTING.
Twelve hundred entries from the golden age of cast metal — how bells are founded, why brass is not bronze, what a cupola melts and a core withstands — by Simpson Bolland, the trade's great teacher.
A vent from a hollow core led to some distance by means of an underground flue, where there will be no possibility of sparks igniting the gas and causing an explosion. See VENTING.