*Sparking.* The jumping of a spark from one conductor to another due to the high heat developed when the current leaps the gap. *Spark plug.* A plug which has in it two conductors which lead to its inner end, and have their ends in close proximity, across which the current leaps. *Structurally.* The manner in which a device is made of its various parts. *Straight line drive.* The system of transmitting power in an automobile, which consists in employing a train of shafting in a direct line from the engine shaft to the differential. *Stranded (cable).* A conductor, or wire rope, made up of a number of small wire strands. *Storage battery.* A container, or accumulator, of electricity, which is designed to receive a charge of electricity, and to give it forth as required. *Susceptible.* A condition in which the truth is considered probable from a knowledge of all the surroundings. *Superheated.* A substance, such as steam, heated above the normal temperature which is given to it when it is generated. *Surging.* The term applied to a high tension current, which, during the impulses, appears to move back and forth, as though it possessed elasticity. *Symptoms.* Appearances; the outward manifestations of a condition. *Systematic.* Done in regular order. *Technicalities.* The scientific and orderly terms and requirements. *Tension.* Voltage. The force of the current. Also the power applied on a spring, or the amount of force it will exert. *Terminal.* The end, or the starting point, as well as the last or final end of a wire or connection. *Threaded.* The spirally-formed ribs on a bolt or in a nut. *Throttle.* The device on an automobile which opens or closes the discharge port of a carbureter.