The method 1 further including the step of providing a protective, light transmitting coating on {HEAD ~ the external surface} of {TAIL ~ said defined envelope} 
of
The method 1 further including the step of providing a protective , light transmitting coating on { HEAD ~ the external surface } of { TAIL ~ said defined envelope }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL