=Force, Electro-magnetic.= The force of attraction or repulsion exerted by the electro-magnet. It is also known as electric force in the electro-magnetic system. =Foucault Currents.= (_See_ Currents, Foucault.) =Fractional Distillation.= The process of evaporating liquids by heat, the most volatile being the first treated. When that has been evaporated and distilled the heat is raised and the next most volatile liquid is evaporated, and so on until all are evaporated, leaving as a residue the solids that were a part of the original mass of liquid. =Friction.= The effect of rubbing, or the resistance which a moving body encounters when in contact with another body. =Frictional Electric Machine.= An apparatus for the development or generation of high-tension frictional electricity. =Frictional Electricity.= Electricity produced by the friction of dissimilar substances. =Full Load.= A complete load. The greatest load a machine or secondary battery will carry permanently. The full capacity of a motor running at its registered speed for its horse-power. =Furnace, Electric.= A furnace in which the heat is produced by the electric arc. It is the hottest furnace known to man, and temperatures as high as 7500° Fahrenheit have been developed in it. =Fuse, Electric.= A fuse for igniting an explosive charge by electricity. It is made by bringing the terminals or ends of wires close together, so that they will spark when a current passes through them. Or a thin piece of highly resistant wire may be imbedded in an explosive and brought to white heat by current. =Fuse-block.= An insulator having a safety-fuse made fast to it. =Fuse-box.= A box containing a safety-fuse, generally of porcelain, enamelled iron, or some other non-conductor. =Fuse-links.= Links composed of strips or plates of fusible metal serving the purpose of safety-fuses. =Fusing-current.= A current of sufficient strength to cause the blowing or fusing of a metal. G =Galvanic.= Voltaic. Relating to current electricity or the electro-chemical relations of metals. =Galvanic Taste.= A salty taste in the mouth resulting from the passage of a light current from a voltaic battery, the ends of the wires being held to either side of the tongue. This has been called tasting electricity, but it is really the decomposition of saliva on the surface of the tongue, due to electrolysis or the passage of a current through a liquid. =Galvanism.= The science of voltaic, or current, electricity. =Galvanizing.= Coating iron with a thin layer of zinc by immersing the object in the molten metal. =Galvano-faradic.= In medical electricity the shocking-coil. The application of the voltaic current, induced by a secondary current (induction-coil), to any part of the body. =Galvanometer.= An instrument for measuring current strength. A magnetic needle influenced by the passage of a current through a wire or coil located near it.