5D10  Resistance Characteristics
            .20 Resistance Wires
            .40 Electron Motion Model
5D20  Resistivity and Temperature
            .10 Cooled Wire
            .20 Heated Wire
            .30 Carbon and Tungsten Lamps
            .50 Thermistor
5D30  Conduction in Solution
            .10 Conductivity of Solutions
5D40  Conduction in Gases
            .10 Jacob's Ladder
            .42 Thermionic Emission
            .50 Neon Bulb Resistivity
            .80 X-Ray Ionization