{TAIL ~ The hot water} in the tank is maintained at {HEAD ~ a constant level} so that the quantity of water discharged by the dipper is fixed 
{ TAIL ~ The hot water } in the tank is maintained at { HEAD ~ a constant level } so that the quantity of water discharged by the dipper is fixed
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH