LIST OF ILLUSTRATIONS XV 



FIGURE PAGE 



62. A Weather Map of the United States 158 



63. The Same for the Succeeding Day 159 



64. A Blast Furnace 161 



65. A Line of Old-fashioned Charcoal Kilns 161 



CHAPTER VII 



66. Diagram of a Helium Atom 166 



67. (a) Diagram of a Sodium Atom . . . . . . . 169 



(b) Diagram of a Fluorine Atom 169 



68. An X-Ray Photograph . . 175 



CHAPTER VIII 



69. Diagram of Savery's Steam Pump 179 



70. Diagram of Newcomen's Engine 180 



71. Diagram of Watt's Engine 182 



72. Diagram of a Modern Steam Engine 184 



73. Diagram of the Governor of a Steam Engine .... 185 



74. Harvesting and Binding Done by Hand 187 



75. The Power Harvester and Binder 187 



76. An Early Power Loom 188 



77. The First Railroad Train in the United States . . . .190 



78. Two Diagrams of a Gasoline Engine 193 



79. Diagram of a Carburetor 195 



80. Diagram of an Automobile Chassis and the Gear Shift . . 197 



CHAPTER IX 



81. Magnet Holding a String of Nails 201 



82. Pattern of Iron Filings over a Magnet 202 



83. Volta's Crown of Cups 206 



84. A Simple Galvanoscope 208 



CHAPTER X 



85. Diagram of an Electric Telegraph 212 



86. Telegraph Sending Key and Receiving Sounder . . . .213 



87. Laying the Atlantic Cable (Copy of a Contemporary Print) . 214 



88. Diagram of a Telephone Receiver 218 



89. Diagram of a Microphone Transmitter 219 



90. A Modern Telephone Exchange Switchboard . . . .220 



91. Diagram of an Electric Bell 221 



92. Diagram of Buzzer, Push Button, and Batteries Properly Con- 



nected 222 



93. Several Types of Batteries 224 



