Furnace has {HEAD ~ a melting section} and a withdrawal section bounded by {TAIL ~ side walls} of refractory material which extend to a glass outlet formed by an overflow edge remote from the melting section 
Furnace has { HEAD ~ a melting section } and a withdrawal section bounded by { TAIL ~ side walls } of refractory material which extend to a glass outlet formed by an overflow edge remote from the melting section
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH