DEVELOPMENT OF THE TELEGRAPH 



The telegraph so perfected represents the practical 

 telegraph of to-day. Hundreds of minor modifications 

 have been made, of course, and are being made year by 

 year, but the principle involved remains the same in all 

 forms of the Morse telegraph, which represents at least 

 ninety-five per cent, of all telegraphs the world over. In 

 England for many years the needle telegraph, used by 

 certain railroads, rivaled the Morse telegraph in popu- 

 larity, particularly as the famous inventors, Cook and 

 Wheatstone, had given great attention to that form of 

 instrument. But for the last quarter of the century at 

 least, there has been no rival of the Morse instrument 

 that could be considered in any sense a competitor. 



MULTIPLE MESSAGES 



Early in the history of telegraphy the possibility of 

 sending messages in opposite directions at the same 

 time was conceived, and in 1853 an Austrian, Doctor 

 Gintl, invented an instrument by which this could be 

 accomplished. In this instrument a relay with coils 

 wound with two separate wires was made. In one of 

 these wires the current of the line batteries circulated, 

 and in the other flowed a current from what is called 

 an "equating" battery. These two coils, which were 

 wound in opposite directions on the soft-iron cores, 

 had opposite magnetic effects upon the relays when con- 

 nected in the proper circuits ; so that although the whole 

 circuit of one battery might pass through both relays, 

 only one of them would be affected by messages coming 

 from the instrument designed to affect that particular 



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