LIST OF ILLUSTRATIONS. xiii 
Fig. 
150 Single-needle Manipulator 
151 Keys and Connections. . 
152 Keys and Connections .... 
153 Thomson’s Mirror Galvanometer . 
154 The Distributor Key .... 
155 The Water Resistance .... 
156 Diagram of Connections .... 
157 Diagram of Connections . . 
158 The Siphon Recorder .... 
159 Smith’s Commutator .... 
160 Diagram of Connections .... 
161 The Siphon Connections 
162 Connections of the Morse Receiver (diagram 
163 The Morse Instrument (Siemens’) 
164 The Morse Instrument (Digney’s) 
164ft The Morse Instrument 
165 Relay Connections (diagram) . 
166 Siemens’ Polarized Relay 
167 Siemens’ Polarized Relay (contacts) . 
168 The Morse Key ..... 
169 The English Post-Office Key 
170 Wheatstone’s Perforator . . 
171 Wheatstone’s Perforator (diagram) . 
172 Wheatstone’s Perforator (diagram) 
173 Wheatstone’s Receiver .... 
174 Morse Printer ..... 
175 Diagram of Connections .... 
176 Hughes’Printing Telegraph 
177 Electro-Magnet ..... 
178 Diagram of Duplex Telegraphy . 
179 Illustration of Duplex Telegraphy 
180 Diagram of Duplex Connections . 
181 Diagram of Artificial Line 
182 Diagram of Artificial Line . 
183 Diagram of Duplexed Cable 
184 Distributor for Telegraph Offices . 
185 Lightning Conductor .... 
186 Bright’s Protective Apparatus 
187 Thomson’s Mirror Galvanometer 
188 Diagram of Connections for Faults 
• ♦ • • 
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210 
219* 
220 
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235 
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268 
