146 THE ELECTRIC TELEGRAPH. 



relay of the opposite station, the tongue of which is consequently 

 pressed firmly against the stone. 



2. APPARATUS I. AND IT. TRANSLATE. 



POSITION II. 



Both translation commutators in T. 



Both current commutators at 1, and both circuit breakers 

 stoppered. The self-releasing clockwork is in action in both in- 

 struments. In this case a positive current from the opposite station 

 would take the following direction : 



Z, (1, Bp 2) (C p T] i, i, (1, 2 , *p 4) n, n, 4, BI (1, P,, 3) 

 (1, Gp 2) (2, F p 4) Z, Mp JE, PL, and through the earth 

 to the opposite station battery. 



The relay G, completes the local circuit, and therefore both 

 magnets of the printing instrument, Hp become active ; the 

 releasing magnet allowing the clockwork to run, and the printing 

 magnet working the beam. When, in so doing, the printing lever 

 touches the contact, 3, the battery -f-K is put in circuit with 

 the line, Z 2 , and when it touches the contact, 2, the counteracting 

 battery K will be similarly put in circuit with the same line. 



3. APPARATUS I. INTERMEDIATE BETWEEN BOTH LINES. 

 POSITION III. 



a) For receiving legible signals from L l the commutators of Appa- 

 ratus Z must be respectively in S and 1. 



In Apparatus II. the translating commutator is in D, and com- 

 munication with the earth cut off at M l and M 2 . 



b) For receiving signals from Z 2 , on Apparatus Z, the com- 

 mutators are in /Sand 2 ; in Apparatus ZZ, translating commutator 

 in D, communication with the earth being cut off at M, and M 2 . 



When the commutator of the Apparatus ZZ is stoppered in Z>, 

 the latter instrument is entirely out of circuit, by the connection 

 (c 2 , D) Z ; while a current coming from Z, will pass through Z p 

 l (c,),!, 1, f y 4 of D, 1 and 3 of F lt Z, Z y D of <7 2 , and so on 

 toZ e . 



88. The Sounder. In America the method of reading by 

 sound has almost entirely superseded that of recording. The 

 apparatus used is called a sounder. In consists simply of an 

 electro-magnet erected on a wooden base board, with an 



