Xll CONTENTS. 



VI. ELECTRO-CHEMICAL TELEGRAPHS. 



Page 



99. Bain's Chemical Telegraph 176 



100. Pouget-Maisonneuve's Chemical Telegraph 179 



101. Bonelli's Printing Telegraph 182 



VII. OVERLAND LINES. 



102. Posts . . . . . ...... 185 



1 03. Line Insulators . . . .._... 189 



104. Stretching Insulators . . . . . ^. ........ . 193 



VIII. ATMOSPHERIC ELECTRICITY. 



105. Lightning Guards Steinheil's 206 



106. ,, Meissner's . 207 



107. ,, Siemens' 208 



108. ,, Breguet's. . , ;.-...;. . . 209 



109. Fardley's . ........ . . 210 



110. ,, Nottebohm's 210 



111. Siemens and Halske's Point . . . 211 



112. Breguet's Improved 211 



113. ,, German . . . . . . .... 212 



114. Kirchhoff's . . . ,. 213 



115. Bianchi's Vacuum . 213 



SECOND PART. 



ELEMENTS OF THE SCIENCE AND PRACTICE OF ELECTRIC 

 TELEGRAPHY. 



I. ORIGIN OF THE GALVANIC CURRENT. 



11. Polarisation of Metals in Liquids . . . . . .\. . . 215 



2. Effects of the Galvanic Current , , '. . . . . . . 218 



3. Batteries . . .' 220 



4. Daniell's Constant Battery 221 



5. Kramer's Modification of ditto 224 



6. Meidinger's ,, 224 



7. Siemens' ,, ,, .......... 226 



8. Varley's ,, .'.-.-.-..- 227 



