“_Sticking of valves._” Inability to work caused by the introduction into the valves of sand, soil, etc.; or it may be caused by too tight a fit of the moving parts, rust or corrosion. [Illustration: STREET ELBOW.] _Street elbow._ An elbow having an extension piece at one end. _“Stroke” of pump._ The distance traveled by the piston in one motion. [Illustration: STUD-BOLT.] _Stud-bolt._ A piece of round bar metal with a thread upon each end. A represents thread for nut; B body of bolt and C thread to fit in casting. [Illustration: STUB-END.] _Stub-end._ Either end of a connecting rod. [Illustration: STRAINER.] _Strainer._ A device for separating solid particles from the liquid which contains them. _Stuffing box._ A recess to receive the packing around piston rods, plungers and valve stems. _Submerged pump._ A pump which works under water. “_Sucking wind._” A leakage of air into the suction part of a pump. _Supplemental piston._ The piston which operates the main valve in the steam pump. [Illustration: SWING CHECK VALVE.] _Swing check valve._ One which swings upon a pivot or hinge in opening and closing. [Illustration: SWITCH COCK.] _Switch cock or valve._ A device for conducting exhaust steam into the smoke stack or atmosphere. A three-way cock. [Illustration: SYPHON COCK.] _Syphon Cock._ A cock having a combined chamber which is partially filled with water of condensation, attached to a steam gauge to keep steam from entering and damaging the works of the instrument. [Illustration: THUMB-NUT.] _Thumb-nut._ The same as a wing-nut, but a smaller size of the two, shown above, applied to hand-vice. _Tobin-bronze._ An alloy of copper, tin and zinc treated in a special manner; it is non-corrosive, has great tensile strength and can be forged at a cherry red heat. “_Trailing Water._” Water can be trailed, _i.e._, carried through pipes to pumps a very great distance so long as “the lift” is not over 25 to 33 feet. “_Trompe._” The term used to designate a water-blast—a form of pump. _Turbine._ A water wheel driven by the impact or reaction of streams of water flowing through it or by the impact and reaction combined; it is also distinguished by the manner in which it discharges the water, as _outward, vertical or central discharge_ turbine wheels. _Turbine-pump._ A pump in which water is raised by the action of a turbine wheel driven by exterior power in the opposite direction from that in which it is turned when used as a motor. [Illustration: TUBE-PLUG.] _Tube-plug._ A tube stopper to be used in case of a leak in a boiler tube; it consists of two wood pistons joined together so that the leak will come between them. Tube plugs are frequently made of turned tapered cast iron, one of which is to be driven into each end of a leaking tube. [Illustration: UNION.]