NEW YORK 



BOSTON 



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Figure 48. — Western Union's first practical quadruplex 

 circuit, 1874. From G. B. Prescott, The Speaking Telephone, 

 New York, 1878, p. 311. 



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Figure 49. — Diagram of tlie Baudot multiplex system. From 

 La Lumiere ilectrique, 1882, \'ol. 6, p. 60. 



mounted on a resonator. The electromagnet made instrument, the sound heard by pressing the ear against 



the needle vibrate according to the rate at which the the cover of the receiver was said to be similar to that 



diaphragm in the transmitter vibrated, and the of a human voice as filtered through a toy trumpet, 



resonant box gave the vibrations a greater intensity. It is difficult to deterinine how well Reis' telephone 



This vibration probably was magnetostriction rather could reproduce articulate sounds. The American 



than the vibration of the ordinary telephone dia- courts involved in the telephone patent trials declared 



phragm. If one spoke into the transmitter of a good flatly that the instrument could not reproduce speech 



PAPER 29: DEVELOPMENT OF ELECTRICAL TECHNOLOGY IN THE 19TH CENTURY: II 



313 



