tbe Electric Celegrapb. 99 



instrument, key and battery in Boston, the 

 same as at the New York end, and into the 

 Around, leaving the earth to complete one-half 

 of the circuit. When the keys at both ends are 

 closed the batteries are active and the arma- 

 tures or " keepers " are attracted so that the 

 a mint ure levers rest on the forward stops. 

 (See diagram Fig. 2.) If either one of the 



NCW HAVCM 

 C 



A gives a diagram view of a Morse telegraph-line with three 

 stations. B is the battery; C C C, the transmitting keys in 

 the three offices; D D D, the relay magnets; E E E, the arma- 

 tures that are actuated by the magnets. 



keys is opened the current stops flowing and 

 the magnetism vanishes from all the electro- 

 magnets on the line, and a spring or retractile 

 of some kind pulls the armatures away from 

 the magnets and the levers rest on their back 

 stops. In this way all the levers of all the 

 magnets are made to follow the motions of 

 any key. If there are moro than two magnets 

 in circuit (and there may be twenty or more) 

 they all respond in unison to the working of 

 one key, so that whrn :my on<- station is send- 

 ing a dispatch all the other stations get it. 



