{HEAD ~ The surface} of the crucible 10 is covered by {TAIL ~ a housing} 18 into which a reducing gas is introduced at an inlet 19 so as to flow generally contrary to the flow of metal in the crucible 10 which will thus be exposed to the reducing action of the gas 
is covered by
{ HEAD ~ The surface } of the crucible 10 is covered by { TAIL ~ a housing } 18 into which a reducing gas is introduced at an inlet 19 so as to flow generally contrary to the flow of metal in the crucible 10 which will thus be exposed to the reducing action of the gas
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH