MAGNETIC TELEGRAPH. 33 



distances so great that the voice cannot be heard, 

 had been well known to organized societies from 

 remote antiquity. Visible signals, made by mov- 

 ing vanes by day, and lighted torches by night, 

 were known to Greeks and Eomans alike; and 

 more recently the alphabet was associated with 

 these movements, so that alphabetical messages 

 were freely communicated. 



Even barbarous nations and tribes possessed this 

 art in a high degree of perfection; and the arrival 

 and progress of Cortes in Mexico were communi- 

 cated by telegraphic signals, corresponding with 

 the sign language of the Aztecs, to the capital of 

 the doomed Montezuma. 



When atmospheric electricity came to be artifi- 

 cially generated, it occurred at once to ingenious 

 men that it might be used for telegraphy; and, in 

 1774, the first electric telegraph ever constructed 

 was established at Geneva by Lesage. He used 

 twenty -four wires, each connected with an electro- 

 scope, whose function it is to move when the wire 

 is charged with electricity, and by means of 

 which any of the letters of the alphabet could 

 be transmitted, by simply discharging a prime 

 conductor of an electrical machine into the 

 wire corresponding to that letter. This com- 

 plicated apparatus was subsequently improved 

 by using only one wire, and causing lettered 

 wheels to revolve synchronously at the two sta- 



