d) measuring {HEAD ~ the flow} of air from said second compartment through {TAIL ~ said outlet means}; and 
through
d ) measuring { HEAD ~ the flow } of air from said second compartment through { TAIL ~ said outlet means } ; and
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH