The analyzer being programmed to derive, from the velocity measurement made within the single chamber, information relating to {HEAD ~ the level} of {TAIL ~ the gaseous substance} to be monitored 
The analyzer being programmed to derive , from the velocity measurement made within the single chamber , information relating to { HEAD ~ the level } of { TAIL ~ the gaseous substance } to be monitored
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH