For example: gla.s.s and rubber are dielectrics.

Discharge. The current flowing from an acc.u.mulator.

Disintegration. The breaking up of the plate or active material.

Disruptive. A static discharge pa.s.sing through a dielectric.

Duplex Wire. A pair of wires usually twisted together and insulated from each other to form the conducting circuit of a system.

Dynamic Electricity. The term applied to a current flowing through a wire.

Dynamo. An apparatus, consisting of core and field magnets, which, when the core is turned, will develop a current of electricity.

Earth Returns. Instead of using two wires to carry a circuit, the earth is used for what is called the _return_ circuit.

Efficiency. The total electrical energy produced, in which that wasted, as well as that used, is calculated.

Elasticity. That property of any matter which, after a stress, will cause the substance to return to its original form or condition. Electricity has elasticity, which is utilized in condensers, as an instance.

Electricity, Lightning, and, in short, any current or electrical Atmospheric. impulse, like wireless telegraphic waves, is called _atmospheric_.

Electricity, Electricity with a low potentiality and large current Voltaic. density.

Electrification. The process of imparting a charge of electricity to any body.

Electro-chemistry. The study of which treats of electric and chemical forces, such as electric plating, electric fusing, electrolysis, and the like.

Electrode. The terminals of a battery, or of any circuit; as, for instance, an arc light.

Electrolyte. Any material which is capable of being decomposed by an electric current.

Electro-magnetism. Magnetism which is created by an electric current.

Electrometer. An instrument for measuring static electricity, differing from a galvanometer, which measures a current in a wire that acts on the magnetic needle of the galvanometer.

Electro-motive Voltage, which is the measure or unit of e. m. f.

Force. (E. M. F.)

Electroscope. A device for indicating not only the presence of electricity, but whether it is positive or negative.

Electro-static Surfaces separated by a dielectric for opposite Acc.u.mulator. charging of the surface.

Element. In electricity a form of matter, as, for instance, gold, or silver, that has no other matter or compound. Original elements cannot be separated, because they are not made up of two or more elements, like bra.s.s, for instance.

Excessive Charge. A storage battery charged at too high a rate.

Excessive Discharge. A storage battery discharged at too high a rate.

Excessive Overcharge. Charging for too long a time.

Exciter. A generator, either a dynamo or a battery, for exciting the field of a dynamo.

Exhaustive Discharge. An excessive over-discharge of an acc.u.mulator.

F. The sign used to indicate the heat term Fahrenheit.

Fall of Voltage. The difference between the initial and the final voltage in a current.

Field. The s.p.a.ce or region near a magnet or charged wire.

Also the electro-magnets in a dynamo or motor.

Flow. The volume of a current going through a conductor.

Force, Electro-magnetic. The pull developed by an electro-magnet.

Frictional A current produced by rubbing dissimilar Electricity. substances together.

Full Load. The greatest load a battery, acc.u.mulator or dynamo will sustain.

Galvanic. Pertaining to the electro-chemical relations of metals toward each other.

Galvanizing. The art of coating one metal with another, such, for instance, as immersing iron in molten zinc.

Galvanometry. An instrument having a permanently magnetized needle, which is influenced by a coil or a wire in close proximity to it.

Galvanoscope. An instrument, like a galvanometer, which determines whether or not a current is present in a tested wire.

Generator. A term used to generally indicate any device which originates a current.

German Silver. An alloy of copper, nickel and zinc.

Graphite. One form of carbon. It is made artificially by the electric current.

Grid. The metallic frame of a plate used to hold the active material of an acc.u.mulator.

Gravity. The attraction of ma.s.s for ma.s.s. Weight. The accelerating tendency of material to move toward the earth.

Gutta Percha. Caoutchouc, which has been treated with sulphur, to harden it. It is produced from the sap of tropical trees, and is a good insulator.

Harmonic Receiver. A vibrating reed acted on by an electro-magnet, when tuned to its pitch.

High E. M. F. A term to indicate currents which have a high voltage, and usually low amperage.

Igniter. Mechanism composed of a battery, induction coil and a vibrator, for making a jump spark, to ignite gas, powder, etc.

I. H. P. Abbreviation, which means Indicated Horse Power.

Impulse. A sudden motion of one body acting against another.