HISTORY AND PROGRESS. 



149 



the working contact, close the local battery and work the 

 Morse. 



Fig. 82 shows the connections of the apparatus for two 

 stations with the Morse recorder. R and R' are the polarised 

 relays, the coils of which are connected with line and with 

 the levers of the keys T and T' respectively. To the back 



Station,! 



Stu.tion.JI. 



*-' 



Line 



Fig. 82. 



contacts of the keys are brought the opposite poles of the 

 two line batteries ; L B having the zinc and i/ B' the copper 

 pole to earth. The front contacts of the keys are used only 

 as stops or anvils without electrical connections. Between 

 the working contacts of the relays and their armatures, the 

 local batteries B B' and the Morse apparatus M M' are inserted. 

 Whilst the keys repose on the back contacts, as shown in the 

 figure, the currents of the two line batteries circulate, in the 

 same direction, through the line and coils of the relays : that 



