oats;
rule for proportioning paddle wheels;
benefits of large floats.
Paddle wheels, feathering, description of;
details of.
Paddles and screw combined.
Parallel motion, description of,
how to lay off centres of.
Pendulum,
cause of vibrations of;
relation of vibrations of pendulum to velocity of falling bodies;
conical pendulum or governor.
Penn, Messrs., engines of "Great Britain," by,
direct acting screw engines by;
trunk engines by.
Performance of locomotives.
Pillars, hollow, strength of,
law of strength varies with thickness of metal.
Pipe for receiving screw shaft.
Pipes of marine engines.
Piston, description of,
how to pack with hemp.
Pistons, metallic packing for.
Pistons for oscillating engines.
Pistons, how to fit and finish.
Pistons of locomotives.
Piston rod, description of,
strength proper for.
Piston rods of locomotives.
Piston rod of oscillating engine.
Piston rods of direct acting screw engine.
Pitch of the screw.
Pitch, increasing or expanding.
Pitching motion in locomotives.
Planometers, or face plates.
Plummer blocks of shafts and trunnions of oscillating engines.
Plummer blocks for receiving thrust of screw propeller.
Plunger of feed pump.
Portable engine, Hoadley's.
Porter's patent governor.
Ports of the cylinder, area of.
Pot-lid valves of air pump.
Powers, mechanical,
misconception respecting.
Power, horses, definition of,
nominal and actual power;
power of high pressure engines.
Power necessary for thrashing and grinding corn, working sugar mills,
spinning cotton, sawing timber, grossing cotton, blowing furnaces,
driving piles, and dredging earth out of rivers.
Pressing cotton, power necessary for.
Priming, nature and causes of.
Priming, if excessive, may occasion explosion.
Propeller, screw, description of.
Proportions of screws with, two, four, and six blades.
Proving of boilers.
Prussiate of potash for case hardening.
Pumping engines, mode of erecting,
mode of starting.
Pumps, loss of effect in, at high speed and with hot water,
causes of this loss;
remedy for.
Pumps used for mines.
Pump, air, description, of,
action of.
Pumps, air, proper proportions of,
single and double acting.
Pump, centrifugal, better than common pump.
Pump, cold water, description of.
Pump, feed, description of,
action of;
proper dimensions of;
rule for proportioning;
plunger of;
valves of;
independent.
Pump valves for mine