By providing two movable members the dip rings carried thereby may be of different sizes and arranged oppositely in {TAIL ~ their first and second positions} to emit an essentially continuous stream of {HEAD ~ alternately large and small bubbles} 
By providing two movable members the dip rings carried thereby may be of different sizes and arranged oppositely in { TAIL ~ their first and second positions } to emit an essentially continuous stream of { HEAD ~ alternately large and small bubbles }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD