The force necessary to rotate {HEAD ~ the elongated tubular member} 30 and thus electrode 42 is provided by {TAIL ~ an electric motor} 68 disposed within framework 37 
The force necessary to rotate { HEAD ~ the elongated tubular member } 30 and thus electrode 42 is provided by { TAIL ~ an electric motor } 68 disposed within framework 37
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH