=Lineman.= A workman whose business is the practical part of electrical construction in lines and conducting circuits. =Link-fuse.= A plate of fusible metal in the shape of a link. It is used as a safety-fuse in connection with copper terminals. =Liquefaction, Electric.= The conversion of a solid into a liquid by the sole agency of electricity in its heat action upon the solid. =Liquid Resistance.= (_See_ Resistance, Liquid.) =Lithanode.= A block of compressed lead binoxide, with platinum connections, for use in a storage battery. =Litharge.= Yellow-lead. A chemical form of metallic lead. =Load.= In a dynamo, the amperes of current delivered by it under given conditions of speed, etc. =Local Action.= In a battery, the loss of current due to impurities in the zinc. The currents may circulate in exceedingly minute circles, but they waste zinc and chemicals and contribute nothing to the efficiency of the battery. In a dynamo, the loss of energy through the formation of eddy currents in its core or armature, in the pole pieces, or in other conducting bodies. =Lodestone.= The scientific name is magnetite. Some samples possess polarity and attract iron; these are called lodestones. =Loop.= A portion of a circuit introduced in series into another circuit. =Low Frequency.= A frequency (in current vibrations) of comparatively few alternations per second. =Low Potential Current.= (_See_ Current, Low Potential.) =Luminescence.= The power or properties some bodies have of giving out light when their molecular mass is excited. For example, phosphorus and radium. =Luminous Heat.= The radiation of heat by electric current, which at the same time produces light. For example, the filament in an incandescent lamp. =Luminous Jar.= A Leyden-jar whose coatings are of lozenge-shaped pieces of tin-foil between which are very short spaces. When discharged, sparks appear all over the surface where the small plates of metal nearly join. M =Magnet.= A substance or metal having the power to attract iron and steel. =Magnet-bar.= A magnet in the shape of a straight bar. (_See_ Bar-magnet.) =Magnet-coil.= A coil of insulated wire enclosing a core of soft iron through which a current of electricity is passed to magnetize the iron. =Magnet-core.= An iron bar or mass of iron around which insulated wire is wound in order to create an electro-magnet. =Magnet, Electric.= A magnet consisting of a bar of iron, a bundle of iron wires, or an iron tube, around which a coil of insulated wire is wound. When a current is passing through the coil its influence magnetizes the iron core, but directly the current ceases the magnetism disappears. =Magnet, Field.= The electro or permanent magnet in a dynamo or motor, used to produce the area of electric energy.