The Progress of Invention in the Nineteenth Century.
CHAPTER VIII.
THE TELEPHONE.
Preliminary Suggestions and Experiments of Bourseul, Reis, and Drawbaugh. First Speaking Telephone by Prof. Bell. Differences between Reis’ and Bell’s Telephones. The Blake Transmitter. Berliner’s Variation of Resistance and Electric Undulations, by Variation of Pressure. Edison’s Carbon Microphone. The Telephone Exchange. Statistics.