xvi LIST OF ILLUSTRATIONS 



FIGURE PAGE 



94. Diagram of Batteries Connected "in Series" and "Parallel" and 



of Water Tanks by Way of Analogy 226 



95. Diagram of an Ammeter 227 



96. Diagram of a Kilowatt-Hour Meter 229 



97. Diagram of a Dry Battery 230 



98. Diagram of a Storage Battery 232 



99. Diagram of an Electric Motor Reduced to Simple Terms . . 233 



100. Diagram of a Commercial Electric Motor 235 



101. Diagram of a Toy Motor 237 



102. The Electric Motor on a Sewing Machine 239 



103. Diagram of a Vacuum Cleaner 239 



104.' A Powerful Electric Engine 240 



105. Diagram of a Simple Dynamo 242 



106. A Dynamo with Cored Coils Set Like Cogs 243 



107. A High-Power Transmission Line 244 



108. Diagram of an Electric Light . 246 



109. Diagram of Wiring for Electric House Lights .... 248 

 no. (a) An Electric Heater; (6) An Electric Percolator; (c) An 



Electric Flatiron; (d) An Electric Toaster 249 



CHAPTER XI 



in. Diagram of the Wireless Telegraph Sending Outfit . . . 252 



112. A Spark Gap 253 



113. Diagram of a More Complex Sending Outfit 254 



114. A Train of Damped Waves 256 



115. Diagram of the Receiving Set 256 



116. A Crystal Detector .257 



117. The Radio Room, SS. "Leviathan" 258 



1 1 8. Diagram of a Receiving Circuit 259 



119. A Two-Slide Tuning Coil ... . 260 



120. A More Elaborate Receiving Set 266 



121. A Rotary Variable Condenser 267 



122. Discontinuous and Continuous Waves 267 



123. A Three-Electrode Vacuum Valve 268 



124. The Use of the Vacuum Tube as a Detector 269 



125. Power Tubes for Transmission. Radio tron Vacuum Tubes . 271 



126. The Heterodyne. Use of the Vacuum Tube as a Generator . 272 



127. Diagram of Voice Modulation of Continuous Waves . . . 275 



128. The Radio Telephone Transmitter 276 



129. The Operating Room of a Broadcasting Station .... 278 



130. A Modern Receiving Set 279 



