The Battery. 5. Spark Coil. 6. Key. 7. Spark-Gap. 8. Aerial Switch. 9. Loose Coupler. 10. Detector, 11. Fixed Condenser. 12. Code Chart. 13. Amateur License. 14. Aerial. 15. Telephone Receivers. .......................................... Fig. 242.—A Simple Electric Motor which may be made in Fifteen Minutes. .......................................................... Fig. 243.—Details of the Armature of the Simplex Motor. ........... Fig. 244.—The Armature. ........................................... Fig. 245.—The Field. .............................................. Fig. 246.—The Field and Commutator. ............................... Fig. 247.—The Bearings. ........................................... Fig. 248.—The Complete Motor. ..................................... Fig. 249.—Details of the Motor. ................................... Fig. 250.—Complete Motor. ......................................... Fig. 251—A Telephone Magneto. ..................................... Fig. 252.—The Principle of the Alternator and the Direct-Current Dynamo. ........................................................... Fig. 253.—Details of the Armature, Commutator, and Brushes. ....... Fig. 254.—The Complete Generator. ................................. Fig. 255.—Details of the Field Casting. ........................... Fig. 256.—Details of the Armature Casting. ........................ Fig. 257.—Details of the Commutator. .............................. Fig. 258.—Diagram showing how to connect the Armature Winding to the Commutator. ....................................................... Fig. 259.—Details of the Wooden Base. ............................. Fig. 260.—The Pulley and Bearings. ................................ Fig. 261.—The Brushes. ............................................ THE JUNIOR DYNAMO MOUNTED ON A LONG WOODEN BASE AND BELTED TO A GROOVED WHEEL FITTED WITH A CRANK SO THAT THE DYNAMO CAN BE RUN AT HIGH SPEED BY HAND POWER. THE ILLUSTRATION ALSO SHOWS A SMALL INCANDESCENT LAMP CONNECTED TO THE DYNAMO SO THAT WHEN THE CRANK IS TURNED THE LAMP WILL LIGHT. ....................................... Fig. 262.—Complete Dynamo. ........................................ Fig. 263.—Complete Electric Railway operated by Dry Cells. Note how the Wires from the Battery are connected to the Rails by means of the Wooden Conductors illustrated in Figure 277. .................. Fig. 264.—Details of the Floor of the Car. ........................ Fig. 265.—Details of the Bearing which supports the Wheel and Axle. Fig. 266.—The Wheels and Axle. .................................... Fig. 267.—The Motor. .............................................. Fig. 268.—The Complete Truck of the Car without the Body. ......... Fig. 269.—Pattern for the Sides and Ends of the Car. .............. Fig.