102 Address. [Feb, 



several thousands of miles away, but also a series of inland lines of 

 perhaps greater extent than any other country in the world, except 

 Russia and the United States, any means of increasing the carrying 

 power of the lines must be of special importance. It is satisfactory, 

 therefore, to be able to record that during the present year the system of 

 quadruples telegraphy has been perfected in India, so that four messages 

 can now be transmitted simultaneously over the same wire, two in one 

 direction and two in the other. Bombay and Madras work quadruples 

 direct; Calcutta works quadruples with Agra or Allahabad on one 

 line, and with Akyab or Rangoon on another ; and the results obtained 

 over these very long circuits have been most satisfactory. The system 

 m use is the same as that used in America and in England, with the 

 apparatus altered in certain important respects to suit the conditions 

 of Indian telegraphy. Four signallers are employed at each end of 

 the wire, two in despatching messages and two in receiving them, each 

 man working a separate instrument. One wire thus keeps eight men 

 fully employed, and it is easy to conceive the great saving in plant, 

 thus gained. The difficulties met with at first have now been all 

 overcome and the future extensiou of the system in India depends only 

 on traffic requirements. It will be within the memory of many of the 

 members present that our lamented fellow-member Louis Schwendler 

 took a very prominent part in the introduction of Duplex telegraphy 

 into India, and described the general theory of its working very f ally 

 in our Journal, Part II, for 1873-74-75. It would have been a great 

 pleasure to him could he have lived to see the perfection and exten- 

 sion of his labours. 



Another great advance in Indian telegraphy is the substitution of 

 hard copper wire for the ordinary galvanised iron wire. The trials of 

 the copper wire were so satisfactory, that it has now been put up for the 

 whole distance (800 miles) Bombay to Madras, also from Bombay 

 towards Nagpur, and on shorter sections. The great advantages of 

 copper wire lie in its high conductivity and virtual freedom from electro- 

 magnetic inertia, which tends to retard the flow of the electric current 

 through iron wire. This really means that within certain limits two 

 offices will work as well with one another through 1000 miles of copper 

 wire as they would through 500 miles of iron wire. It is on this copper 

 wire that Bombay and Madras work quadruples direct and work excel- 

 lently ; in fact, better than they formerly did on an iron wire, which 

 necessitated automatic repetition or translation at Bellary. 



Another improvement to be recorded is the introduction of mica 

 ' lightning-dischargers ' in telegraph offices. These lightning- dischargers 

 are placed at either end of a telegraph line where it enters an office in 



