The discharge vessel encloses a discharge space having {HEAD ~ an ionizable filling} which, in addition to Hg, contains {TAIL ~ a quantity} of iodide of Na, Tl, Ho and Ca 
contains
The discharge vessel encloses a discharge space having { HEAD ~ an ionizable filling } which , in addition to Hg , contains { TAIL ~ a quantity } of iodide of Na , Tl , Ho and Ca
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH