{HEAD ~ Apparatus} 36 includes {TAIL ~ a tube} 37, having a pump 38 at one end and gas entry pipes 39 and 40 shown for convenience as being at the other end 
includes
{ HEAD ~ Apparatus } 36 includes { TAIL ~ a tube } 37 , having a pump 38 at one end and gas entry pipes 39 and 40 shown for convenience as being at the other end
HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH