Abstract: An automatic, fluid actuated, external control system for a pile hammer or the like is provided that can vary the operating stroke length of a pile hammer and that can be used to operate the pile hammer in either a continuous or single stroke mode. A series of axially spaced orifices in the hammer housing exhaust pressurized fluid from the housing in a sequence controlled by the position of the hammer piston within the housing. The orifices are coupled by conduit to a series of pressure sensitive valves external of the pile hammer. The pressure sensitive valves control the delivery and exhaust of pressurized motive fluid to and from the pile hammer in response to the position of the hammer piston within the hammer housing.

Abstract: A froth-aid useful in frothing a carboxylated latex for use as an adhesive in the manufacture of carpets comprises in certain proportions urea, the sodium salt of condensed naphthalene sulfonic acid, a blend of about C.sub.8 to C.sub.18 fatty alcohols, ammonium or sodium lauryl sulfate and water.