56 



THE ELECTRIC TELEGRAPH. 



ing parts of the wheels, by the action of a single electric 

 wave or impulse. 



A clockwork at each station turns, with a continuous and 

 uniform motion, an axle, at the extremity of which the type- 

 wheel is supported. The synchronism is attained by the aid 

 of a vibrating spring and anchor escapement. The rotation 

 of the type-wheel is transmitted to a vertical arbor, fur- 

 nished at its lower extremity with a horizontal arm tra- 

 velling over a circular disc, in which is arranged a series of 

 contact pins, in number corresponding to the types. Each 



: 



; 



4.. 



ft- 1 9 



Fig. 27. 



pin therefore represents a letter, and is raised when it is 

 wished to telegraph this letter along the line. The hori- 

 zontal arm, which travels round the disc with a motion 

 uniform with that of the type- wheel, comes in contact with 

 the pin just at the moment when the corresponding type is 



