*Perspective.* A view of an object which shows all three dimensions from one side. *Pinion.* A small toothed wheel. *Planetary.* A system of gears where two or more mesh with and revolve around a central gear. *Plurality.* Numerous; more than one. *Plumbago.* Graphite; a form of carbon; a lubricant. *Potentiality.* The term applied to the volts and amperes in an electric current. *Positive.* One which deflects a needle to the left. *Pre-ignition.* Where the spark ignites the charge before the piston begins to descend, or ahead of its proper time. *Precision.* A system of oiling the machinery which depends on a pump that sends in a definite amount of lubricant at each turn of the engine. *Predeterminate.* Arranging beforehand. *Preferential.* A more satisfactory manner, or time; estimating one thing above another. *Primary.* The first. As applied to electrical devices it has reference to a battery which generates a current in contradistinction to the secondary or storage battery. *Proportionate.* The ratio to something else. This compared with that. *Properties.* The attributes of matter. *Protective.* That which shields; a covering, or an enclosure. *Progressive.* Proceeding in a direct line. *Propelling.* Moving; drawing; giving motive power. *Pneumatic.* Pertaining to air. *Push leg.* An old system of propelling mechanism for vehicles. Not used in that manner now. The pawl engaging a lever, is the only form in which the push leg is now employed. *Puncture.* A rupture; a hole; a tear. *Quadrant.* One-fourth of a circle. *Radiating.* Moving out in all directions from a common center. *Radiation.* Applied to the movement of heat from a body. *Radiator.* A device which cools water, by the application of air. *Raceway.* A track for the movement and guidance of anti-friction balls.