{TAIL ~ The amount} of {HEAD ~ gas} that escapes each time is measured and programmed into control means 60 
{ TAIL ~ The amount } of { HEAD ~ gas } that escapes each time is measured and programmed into control means 60
TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH