The tubing member is then restricted, a combustion supporting atmosphere introduced therein, and {TAIL ~ the second open end} of the tubing member is sealed to define {HEAD ~ the finished envelope} 
The tubing member is then restricted , a combustion supporting atmosphere introduced therein , and { TAIL ~ the second open end } of the tubing member is sealed to define { HEAD ~ the finished envelope }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD