144.—The Engine Base. ........................................ FIG. 145.—Details of the Electromagnet Bobbin. .................... FIG. 146.—Details of the Engine Frame. ............................ FIG. 147—The Bearings. ............................................ FIG. 148.—Details of the Shaft. ................................... FIG. 149.—The Armature, Armature Bearing and Connecting Rod. ...... FIG. 150.—The Brushes. ............................................ FIG. 151.—A Flywheel may be cut from sheet iron. .................. FIG. 152.—Small Tungsten Battery Lamps. ........................... FIG. 153.—A Simple Lighting Arrangement. .......................... FIG. 154.—Showing the differences between the Candelabra, Single Ediswan and Double Ediswan Types of Lamp Bases. ................... FIG. 155.—Miniature Sockets of the types known as "Flat Base Porcelain," "Pin" and "Weatherproof." ............................. FIG. 156.—Connections for a 2.8 Volt Lamp. ........................ FIG. 157.—A Miniature Base Tungsten Filament Battery Lamp for small lighting. ......................................................... FIG. 158.—A Tungsten Automobile Lamp with Ediswan Base. ........... FIG. 159.—Lamps Controlled by One Switch. ......................... FIG. 160.—Lamps Controlled by Separate switches. .................. FIG. 161.—Double Control System. .................................. FIG. 162.—The Coherer Details. .................................... FIG. 163.—The Complete Coherer. ................................... FIG. 164.—Pony Type Relay. ........................................ FIG. 165.—Connections for the Receiving Set. ...................... FIG. 166.—Coherer, Decoherer and Relay Connections. ............... FIG. 167.—How the Transmitter is Connected. ....................... FIG. 168.—The Complete Spark Gap. ................................. FIG. 169.—Details of Spark Gap. ................................... FIG. 170.—Tesla Coil Circuits. .................................... FIG. 171.—Secondary Tube. ......................................... FIG. 172.—Details of the Secondary Heads. ......................... FIG. 173.—Details of the Primary Head. ............................ FIG. 174.—Primary Cross Bar. ...................................... FIG. 175.—Front View of the completed Tesla Coil. ................. FIG. 176—Side View of the completed Tesla Coil. ................... FIG. 177.—Diagram of connections for operating the Coil. .......... FIG. 178.—Plate Glass Condenser. .................................. FIG. 179.—When a Bar Magnet is plunged into a Hollow Coil of Wire, a Momentary Current of Electricity is Generated. .................... FIG. 180.—Magnetic Phantom showing the Lines of Force about a Bar Magnet.