Clutch Requirements, Frictional Contact. Cone Clutch. Compression Spring in Clutches. The Multiple Disk Clutch. Its Construction. Disadvantages of Multiple-Disk Clutches. Care of Multiple Disk Clutch. CHAPTER VIII. TRANSMISSION, OR CHANGE SPEED GEARS 69-89 Transmission Leverage. Economy of Transmission Gearing. Types of Transmission. The Progressive. Low Gear. Intermediate Gear. High Gear. Reverse. Selective Type. Low Gear. Intermediate Gear. High Gear. Reverse Gear. Control Lever for Progressive Transmission. Operation of the Selective Gear. Selector Bars. Shifting Lever. Speed Selectors. 3-speed Selectors. 4-Speed Selectors. An approved Type of Selector. Controlling the Selector. Using the Clutch and Selector. Planetary Transmission. Frictional Transmission. CHAPTER IX. THE MOTOR 90-108 Value of Fuel Utilized. The Waste. Water Absorption. Engine Types. The Four-Cycle Engine. The Two-Cycle. Compression. Economy of Four-Cycle Engine. Valve Movements. The Ignition point in the Cycle. The Fly-wheel. Impulses in Four-Cycle Engine. The Cylinder Case, and Connections. Piston and Crank Construction. Calculating the Efficiency. Pressures in Explosions. Expansion Line. Mean Effective Pressure. The Two-cycle Engine. Foot Pounds. Work or Energy. Cycle of Operation. The Crank Shaft. Special Metal. Engine Troubles. Difficulties pointed out. Starting the Engine. Carbureter. Low Compression. Mixtures. Spark Plugs. The Weather. Drainage. CHAPTER X. COOLING SYSTEMS 109-117 Air Cooling. Air-Cooling Devices. Water Cooling. Gravity System. Locating the Reservoir. Force System of Cooling. The Radiator Connections. Radiators. Construction of Radiator. Operation of Radiator. The Pump. Pump Construction. Action of Pump. CHAPTER XI. CARBURETERS 118-132 Carbureted Air. Composition of Gasoline. Gasoline Expansion. Requirements of a Carbureter. Evaporation. Air Saturation. Air Contact with Gasoline. Instantaneous Combustion. Compression. Compression as a Mixing Means. Carbureter Types. The Spraying Carbureter. Dissecting the Carbureter. The Mixing Chamber. The Float Chamber. The Venturi Tube. The Inlet Valve. The Throttle Valve. The Secondary Air Supply. Automatic Admission of Secondary Air. Carbureter Adjustments. Special Points Concerning Carbureters. Thin Mixtures. Speeds and Mixtures. Surface Carbureter. The Float. The Oil Inlet. Securing Surface for air Contact. CHAPTER XII. IGNITION SYSTEMS 133-158