XI. APPLICATIONS. 3 1 1 



the Morse alphabet being read by sound from the clicking of the armature 

 lever instead of from the paper band of the recording instrument ; it possesses 

 the advantage of not fatiguing the eye of the operator, and allows him perfect 

 freedom for writing the message. 



1566. Double Current Sounder Translator. 



This is the usual form of apparatus used for relaying double current Morse 

 signals. 



The signals are relayed from the lever of the sounder, the latter being worked 

 by a polarized relay in the line circuit. The necessary alterations to the 

 connexions for restoring the apparatus to its normal condition when trans- 

 mission in either direction has ceased is accomplished by an automatic switch 

 called a " spacer," which consists of an electro-magnet, armature, lever, and 

 stops. The local circuit of this magnet is closed by the relay which works 

 the sounder when a marking current is sent, and by another relay placed in 

 the line circuit when a spacing current is sent, so that the armature is con- 

 tinually held down while a station is sending. 



The armature is prevented from rising during the short interval between the 

 reversals by an electric " shunt," which forms a path for the extra current 

 direct when the local circuit is broken, so that the attraction of the armature 

 is continued. 



1567. Duplex Translator for relaying the signals on long 

 circuits, worked on the duplex system. 



This apparatus really consists of two sets of duplex instruments, which are 

 combined for the purpose. 



1568. Fast Speed Double Current Translator. 



Apparatus used for relaying the signals on long wires, worked by Wheat- 

 stone's automatic system. The main feature of this arrangement is that the 

 tongue of the relay by which the currents (spacing and marking) are trans- 

 mitted is set neutral, so that both currents are sent on with the same facility. 



This, in addition to the currents being relayed from the tongues direct, with- 

 out the intervention of sounders, enables the arrangement to work at a much 

 higher speed than previous "translators" or "repeaters." 



The tongue is maintained in connexion with either " up " or " down " line 

 wires during transmission by a special piece of apparatus called an " automatic 

 switch," which consists of an electro-magnet, armature, and lever connexions, 

 etc. This electro-magnet is worked by two polarised relays in the line circuit, 

 free to move in opposite directions, so that one of these closes the local circuit 

 of the electro -magnet and keeps it down, any tendency to rise being prevented 

 by the use of an electric " shunt." 



When no transmission is taking place the tongues of the relays working the 

 automatic switch fall back into their " rest " stops, and restore the " trans- 

 lator " to its normal condition. 



1569. Testing-Box Galvanometer. 



Used for testing wires ; the requisite changes of connexions for receiving 

 and sending currents are made by a peg switch in front of the instrument. 



1570. Regulator Clock and Apparatus for the distri- 

 bution of Greenwich time current at provincial stations. 



The method by which the time signal is distributed may be summarised as 

 follows : 



The wire by which the signal is to be received from the central station, as 

 well as the wires on which the time signal is to be distributed, are connected to 

 he levers of the electro-magnetic switch. 



