THE ELECTRIC TELEGRAPH.
The Voltaic Pile. Daniell’s Battery. Use of Conducting Wire by Weber.
Steinheil Employs Earth as Return Circuit. Prof. Henry’s Electro-
Magnet, and First Telegraphic Experiment. Prof. Morse’s Telegraphic
Code and Register. First Line Between Washington and Baltimore. Bain’s
Chemical Telegraph. Gintl’s Duplex Telegraph. Edison’s Quadruplex.
House’s Printing Telegraph. Fac Simile Telegraphs. Channing and Farmer
Fire Alarm. Telegraphing by Induction. Wireless Telegraphy by Marconi.
Statistics.