In this way, the stream of {HEAD ~ bubbles} is essentially continuous since one dip ring is raised into {TAIL ~ the air stream} as the other is lowered 
In this way , the stream of { HEAD ~ bubbles } is essentially continuous since one dip ring is raised into { TAIL ~ the air stream } as the other is lowered
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH