said plate member and said floor further cooperating to allow {HEAD ~ gas} to seep from said compartment to said chamber for providing a substantially uniform gaseous environment in said {TAIL ~ chamber} 
said plate member and said floor further cooperating to allow { HEAD ~ gas } to seep from said compartment to said chamber for providing a substantially uniform gaseous environment in said { TAIL ~ chamber }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL